KR20070054221A - Cellulose acylate film, method of producing the same, stretched cellulose acylate film and method of producing the same - Google Patents

Abstract

An unstretched cellulose acylate film which hardly breaks upon stretching can be produced by the melt film forming method, and thus a highly oriented stretched cellulose acylate film can be obtained. By using an extruder having a screw compression ratio of 2.5 to 4.5 and an L / D of 20 to 50, the cellulose acylate resin is extruded into a sheet shape from a die into a cooling drum at an extrusion temperature of 190 ° C to 240 ° C, fixed by cooling and solidified. After the cellulose acylate film 16 is produced, the cellulose acylate film is stretched to produce a stretched cellulose acylate film.

Description

CELLULOSE ACYLATE FILM, METHOD OF PRODUCING THE SAME, STRETCHED CELLULOSE ACYLATE FILM AND METHOD OF PRODUCING THE SAME}

TECHNICAL FIELD The present invention relates to a cellulose acylate film, a method for producing the same, a stretched cellulose acylate film, and a method for producing the same, and in particular, an unstretched cellulose acyl by a melt agent film for producing a stretched cellulose acylate film having a suitable quality for a liquid crystal display device. It relates to a method for producing a late film.

DESCRIPTION OF RELATED ART Conventionally, extending | stretching a cellulose acylate film | membrane, expressing in-plane retardation (Re) and retardation (Rtte) in the thickness direction, and using this film as a phase difference film of a liquid crystal display element, expanding the viewing angle has been performed.

As a method of stretching a cellulose acylate film, a method of stretching in the longitudinal (length) direction (vertical stretching), a method of stretching in the horizontal (width) direction (horizontal stretching), and a method of simultaneously performing longitudinal stretching and transverse stretching (simultaneous stretching) Axial stretching). Among them, longitudinal stretching has been largely used in the past because of its small equipment. In general, longitudinal stretching is carried out in the longitudinal direction by heating the film to a glass transition temperature (Tg) or more between two or more nip rolls, and setting the conveying speed of the outlet side faster than the conveying speed of the nip roll on the inlet side. That's how.

Japanese Patent Laid-Open No. 2002-311240 discloses a method of longitudinally stretching a cellulose ester. Japanese Patent Laid-Open No. 2002-311240 improves the angular nonuniformity of the slow axis by performing longitudinal stretching in the opposite direction to the film direction of the softener. Japanese Laid-Open Patent Publication No. 2003-315551 discloses a method in which an nip roll located between short spans having an aspect ratio (L / W) of 0.3 to 2 or less is provided in the stretching zone and stretched. According to Unexamined-Japanese-Patent No. 2003-315551, the orientation (R in the thickness direction) can be improved. An aspect ratio here means the value obtained by dividing the space | interval L of the nip roll used for extending | stretching by the width W of the cellulose acylate film to extend | stretch.

However, when the stretched cellulose acylate film prepared by the method described in JP-A-2002-311240 and JP-A-2003-315551 is used as a phase difference film of a liquid crystal display element, fine display unevenness can be expressed. As a phase difference film of a liquid crystal display element, it does not yet have sufficient quality.

The cellulose acylate film produced by the conventional melt film forming method tends to be destroyed at the time of stretching when the draw ratio is increased, and when used as a retardation film, a desired in-plane retardation and a retardation in thickness direction Since the draw ratio cannot be increased at a level sufficient to obtain a), there is a drawback that a stretched cellulose acylate film of a high orientation cannot be produced.

The present invention has been made in view of the above circumstances, and since the unstretched cellulose acylate membrane which does not cause stretch breakage when the cellulose acylate film is stretched can be produced by the melt film forming method, a stretched cellulose acylate film with high orientation can be obtained. An object of the present invention is to provide a cellulose acylate membrane, a method for producing the same, a stretched cellulose acylate membrane, and a method for producing the same.

In the manufacturing method of the cellulose acylate film of the 1st aspect of this invention, in order to achieve the said objective, in the manufacturing method of the cellulose acylate film | membrane by a melt film forming method, a screw compression ratio is 2.5-4.5 and L / D. It is a method of extruding a cellulose acylate resin into a sheet form on a cooling support body through a die at the extrusion temperature of 190 degreeC-240 degreeC using the extruder of 20-50, and fixing it by cooling.

When the cellulose acylate film is produced by the melt film forming method, the produced cellulose acylate film tends to become yellow, and the extrusion temperature of the extruder has usually been set low. However, the present inventors have studied the extrusion conditions in consideration of the improvement of the fracture during stretching, which is the problem to be solved above. As a result, when the extrusion temperature is too low, fine crystals remain in the cellulose acylate film, and the crystals are stretched. It was found that when the cellulose acylate film thus prepared was inhibited, film breakage was likely to occur. It has also been found that it is important to set the screw compression ratio and the L / D of the extruder at an appropriate level in order not to leave fine crystals in the cellulose acylate film after production. The present invention is made based on these findings.

According to the first aspect, the cellulose acylate resin is cooled through a die at an extrusion temperature (extruder exit temperature) of 190 ° C to 240 ° C by using an extruder having a screw compression ratio of 2.5 to 4.5 and a L / D of 20 to 50. Since it extrudes to a sheet form and cools and solidifies, a cellulose acylate film | membrane which is hard to turn yellow and which has a low possibility of extending | stretching breakdown when extending | stretching can be manufactured. Here, simply used, "cellulose acylate membrane" means an unstretched cellulose acylate membrane, and the cellulose acylate membrane after stretching is referred to as "stretched cellulose acylate membrane". In addition, a screw compression ratio is a volume ratio of a supply part and a metering part in an extruder, and L / D is ratio of the cylinder length L with respect to the cylinder internal diameter D of an extruder.

In order to achieve the above object, the cellulose acylate film of the second aspect of the present invention has an elongation at break of 50% or more when uniaxially stretched at a glass transition temperature of Tg + 10 ° C.

The 2nd aspect prescribes the breaking elongation of the cellulose acylate film suitable for functional films, such as a phase difference film of a liquid crystal display element, and needs to be 50% or more of the breaking elongation at the time of uniaxial stretching at glass transition temperature Tg + 10 degreeC. Do.

Herein, the elongation at break of 50% or more means that the film can be stretched by 50% or more on the basis of the original size before stretching before the film is destroyed, that is, when the value before stretching is 1, it is 1.5 times or more.

A cellulose acylate film having such a breaking elongation of 50% or more can be produced by the method of the first aspect. The breaking elongation method was preheated for 1 minute in an oven heated to Tg + 10 ° C. using a tensioning device attached to a heating means, for example, “Heated Tensilon” manufactured by Toyo Seiki Co., Ltd. Thereafter, the fracture elongation (difference between stretching after stretching and before stretching) was measured under conditions of 100 mm and a tensile speed of 100 mm / minute between chucks.

In the second aspect, the cellulose acylate film of the third aspect of the present invention has a haze of 2.0% or less, a yellowing degree of 10 or less, and a peak in a region of glass transition temperature Tg or more in a differential scanning calorimeter (DSC) measurement. The value of the endothermic peak at which is represented is 4.0 J / g or less.

The third aspect defines characteristic values of acylate films other than the above-described breaking elongation suitable for functional films such as retardation films of liquid crystal display elements, haze of 2.0% or less, yellowing degree of 10 or less, In the DSC (differential scanning calorimeter), it is necessary that the magnitude of the endothermic peak appearing in the region of the glass transition temperature Tg or more is 4.0 J / g or less.

The cellulose acylate film which has such an optical characteristic can be manufactured by the method of a 1st aspect.

The cellulose acylate membrane according to the fourth aspect of the present invention is the second or third aspect, wherein the cellulose acylate membrane includes A as the degree of substitution of the acetyl group, B as the propionyl group, butyryl group, pentanoyl group, and hexanoyl group. When it is said that the sum total of substitution degree of acylate group, the following substitution degree,

2.5 ≦ A + B <3.0, and

It is a film that satisfies 1.25 ≦ B <3.0.

The cellulose acylate film that satisfies such a degree of substitution has a low melting point, is easy to stretch, has excellent moisture resistance, and, in addition to the above characteristic values, an excellent stretched cellulose acylate film as a functional film such as a phase difference film of a liquid crystal display device. Can be.

The cellulose acylate membrane of the fifth aspect of the present invention is a membrane having a molecular weight of 20,000 to 100,000 in any of the second to fourth aspects. When the molecular weight is 100,000 or more, the melt viscosity is increased, the extrusion temperature is increased, and yellowing is easily caused by thermal deterioration. If the molecular weight is less than 20,000, the mechanical strength when formed into a film decreases.

In order to achieve the above object, the method for producing the stretched cellulose acylate membrane of the sixth aspect of the present invention comprises the prepared unstretched cellulose acylate membrane according to the first aspect at least once in at least one of the longitudinal and transverse directions of the membrane. Stretching at 2.5 times.

A 6th aspect is a manufacturing method of the stretched cellulose acylate membrane which extended | stretched the cellulose acylate membrane manufactured by the method of a 1st aspect. By using the cellulose acylate membrane of the present invention, stretching of 1 to 2.5 times becomes possible. Therefore, the stretched cellulose acylate film which is excellent as a functional film, such as a phase difference film of a liquid crystal display element, can be obtained.

In order to achieve the above object, the stretched cellulose acylate membrane of the seventh aspect of the present invention is one of the unstretched cellulose acylate membrane according to any one of the second to fifth aspects in at least one of the longitudinal and transverse directions of the membrane. It is obtained by extending | stretching by 2 times-2.5 times.

The stretched cellulose acylate film of the seventh aspect can be stretched 1 to 2.5 times by stretching the cellulose acylate film having the characteristic value according to any one of the second to fifth aspects. Therefore, the stretched cellulose acylate film which is excellent as a functional film, such as a phase difference film of a liquid crystal display element, can be obtained.

The said cellulose acylate film of the 8th aspect of this invention is 30-300 micrometers in thickness, 0 nm-500 nm of in-plane retardation, and 30 nm-500 nm of retardation in thickness direction.

The cellulose acylate film of the eighth aspect is stretched from 1 to 2.5 times in at least one direction of the longitudinal and transverse directions of the film, and thus has a thickness of 30 to 300 µm, in-plane retardation, suitable for functional films such as retardation films of liquid crystal display elements. A stretched cellulose acylate film having a (R) of 0 nm to 500 nm and a retardation in the thickness direction of 30 nm to 500 nm is obtained.

In the cellulose acylate film of the ninth aspect of the present invention, in the eighth aspect, the variation of R e and R t is 5% or less in both the width direction and the longitudinal direction.

In the cellulose acylate membrane of the ninth aspect, the cellulose acylate membrane having the characteristic value according to any one of the second to fifth aspects is stretched, whereby the variation of R e and Rt is small to 5% or less in both the width direction and the longitudinal direction. can do.

The 10th aspect of this invention is a polarizing plate which laminated | stacked at least 1 layer of the unstretched cellulose acylate membranes in any one of 1st aspect-5th aspect. An eleventh aspect is a compensation film for a liquid crystal display element panel using the unstretched cellulose acylate film according to any one of the first to fifth aspects as a substrate. A twelfth aspect is an antireflection film containing the unstretched cellulose acylate film according to any one of the first to fifth aspects.

A thirteenth aspect of the present invention is a polarizing plate in which at least one layer of the stretched cellulose acylate film according to any one of the seventh to ninth aspects is laminated. A 14th aspect is a compensation film for liquid crystal display element panels which contained the stretched cellulose acylate film in any one of 7th-9th form as a base material. A fifteenth aspect is an antireflection film containing the stretched cellulose acylate film according to any one of the seventh to ninth aspects as a substrate.

According to the present invention, a highly-oriented stretched cellulose acylate film can be obtained by producing an unstretched cellulose acylate film which is less likely to cause stretching breakage when the cellulose acylate film is stretched.

Therefore, when the stretched cellulose acylate film which has favorable optical characteristic is used in combination with a liquid crystal display element, functional films, such as retardation film which shows high orientation, can be obtained.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to an accompanying drawing, the cellulose acylate film | membrane of this invention, its manufacturing method, the stretched cellulose acylate film | membrane, and the preferable Example of its manufacturing method are demonstrated.

1 illustrates an example of a schematic configuration of an apparatus for producing a stretched cellulose acylate film.

As shown in FIG. 1, the manufacturing apparatus mainly includes a longitudinal stretching step that vertically stretches the uncoated cellulose acylate film produced in the membrane forming step 10 and the membrane forming step 10 for producing the cellulose acylate film before stretching ( 20), the horizontal stretching step portion 30, and the winding step portion 40 to the horizontal stretching.

In the film forming step 10, the cellulose acylate resin melted by the extruder 11 is extruded into a sheet shape through the die 12, and the cellulose acylate film which is quenched and solidified onto the rotating cooling drum 14 ( 16) is prepared. The cellulose acylate film 16 is peeled off from the cooling drum 14 and sequentially sent to the longitudinal stretching step 20 and the horizontal stretching step 30 to be stretched, and then rolled up to the winding step 40. Wind up into shape. Thus, a stretched cellulose acylate film is produced.

In FIG. 2, the extruder 11 of a single screw is shown. As shown in FIG. 2, a single screw 32 having a flight 31 is provided in the screw shaft 28 in the cylinder 26. A cellulose acylate resin is supplied into the cylinder 26 through the supply port 34 from the hopper which is not shown in figure. The cylinder 26 is sequentially supplied from the supply part 34 side, a supply part (area indicated by A) for quantitatively transporting the cellulose acylate resin supplied from the supply part 34, and a compression part B for kneading and compressing the cellulose acylate resin. Area), and a metering unit (area indicated by C) for measuring the kneaded and compressed cellulose acylate resin. The cellulose acylate resin melted in the extruder 11 is continuously supplied from the discharge port 36 to the die.

The screw compression ratio of the extruder 11 is set to 2.5-4.5, and L / D is set to 20-50. Here, the screw compression ratio is the volume ratio of the supply part and the metering part, i.e. (volume per unit length of the supply part A / volume per unit length of the metering part C), the outer diameter d1 of the screw shaft 28 of the supply part A, and the screw of the metering part C. It is computed using the outer diameter d2 of the shaft 28, the groove diameter a1 of the supply part A, and the groove diameter a2 of the metering part C. L / D is the ratio of the cylinder mounting L to the cylinder inner diameter D. Moreover, extrusion temperature is set to 190-240 degreeC. When the temperature in the extruder 11 exceeds 240 degreeC, a cooler (not shown) may be provided between the extruder 11 and the die 12.

The cellulose acylate resin melt | dissolved using the extruder 11 comprised as mentioned above is supplied continuously to the die 12, is extruded in the sheet form on the cooling drum 14, and it is fixed by cooling. Thus, an unstretched cellulose acylate film to be stretched to the longitudinal stretching step 20 and the horizontal stretching step 30 is produced. On the other hand, it is also possible to use a cooling band instead of the cooling drum 14.

According to the method for producing a cellulose acylate film of the present invention, an extruder 11 having a screw compression ratio of 2.5 to 4.5 and a L / D of 20 to 50 is used to die the cellulose acylate resin at an extrusion temperature of 190 ° C to 240 ° C. Since the sheet 12 was extruded in the form of a sheet onto the cooling drum 14 through cooling (12) for cooling, the cellulose acylate film can be produced that is difficult to achieve yellow color and hard to break when stretched. The cellulose acylate membrane produced by the production method of the present invention can be used not only as a raw material membrane for producing the stretched cellulose acylate membrane, but also as a cellulose acylate membrane product.

In the present invention, the extruder 11 may be a single screw extruder or a twin screw extruder. However, if the screw compression ratio is too smaller than 2.5, the extruder 11 is not sufficiently kneaded, an undissolved portion is generated, and the shear heat generation is small. Melting becomes insufficient, and fine crystals remain in the produced cellulose acylate film. In addition, it becomes easy to mix bubbles. Therefore, when extending | stretching a cellulose acylate film | membrane, the remaining crystal | crystallization inhibits elongation and it cannot fully increase an orientation. On the contrary, when the screw compression ratio is larger than 4.5, the shear stress is too high and the resin is easily deteriorated by heat, so that the produced cellulose acylate film becomes yellow easily. In addition, if the shear stress is too high, the molecular breakage occurs, the molecular weight decreases, and the mechanical strength of the film decreases. Therefore, in order to suppress the yellowing of the produced cellulose acylate film and to prevent the stretching breakage, the screw compression ratio is preferably in the range of 2.5 to 4.5, more preferably in the range of 2.8 to 4.2, particularly preferably of 3.0 to 4.0 Range.

In addition, when the L / D is less than 20, fine crystals may remain in the produced cellulose acylate film as in the case where melting and kneading are insufficient and the compression ratio is small. On the other hand, when L / D is too large than 50, the residence time of the cellulose acylate resin in the extruder 11 becomes too long, and resin tends to deteriorate. In addition, the longer the residence time, the more likely the cleavage of the molecules, the lower the molecular weight, the lower the mechanical strength of the membrane. Therefore, in order to suppress the yellowing of the produced cellulose acylate film and to prevent breakage, L / D is preferably in the range of 20 to 50, preferably in the range of 22 to 45, particularly preferably in the range of 24 to 40. to be.

If the extrusion temperature is too lower than 190 ° C, melting of the crystal becomes insufficient, and there is a tendency for fine crystals to remain in the produced cellulose acylate film. When extending | stretching a cellulose acylate film | membrane, elongation is inhibited and orientation cannot fully increase. On the contrary, when extrusion temperature is too high than 240 degreeC, a cellulose acylate resin will deteriorate and the grade of yellowing degree (VII value) will deteriorate. Therefore, in order to suppress yellowing of the produced cellulose acylate film and to prevent stretching breakage, the extrusion temperature is preferably 190 ° C to 240 ° C, preferably 195 ° C to 235 ° C, particularly preferably 200 ° C to It is the range of 230 degreeC.

As described above, the cellulose acylate film of the present invention formed using the extruder 11 having the extrusion conditions set has a fracture elongation of 50% or more (1.5 times before stretching) when uniaxially stretched at a glass transition temperature of Tg + 10 ° C. At the same time, the haze is 2.0% or less, the yellowing degree is 10 or less, and the magnitude of the endothermic peak appearing in the region of the glass transition temperature Tg or more in the differential scanning calorimetry (DSC) measurement is 4.0 J. It has a characteristic value less than / g.

Here, the haze is an index of whether or not the extrusion temperature is too low, that is, an index of the crystal amount remaining in the produced cellulose acylate film. When the haze exceeds 2.0%, the fine crystals remaining in the produced cellulose acylate film increase, and the cellulose acylate film tends to be stretched and broken. The yellowing degree (VI) is an indicator of whether or not the extrusion temperature is too high, and there is no problem in the yellow color point if the yellowing degree (VI) is 10 or less. In the DSC (differential scanning calorimetry) measurement, the endothermic peak appearing in the region above the glass transition temperature Tg is an index of whether or not the extrusion temperature is too low, like haze. When an endothermic peak value exceeds 4.0 J / g, the fine crystal | crystallization which remain | survives in the produced cellulose acylate film | membrane increases, and a cellulose acylate film | membrane becomes easy to extend | stretch and break.

The cellulose acylate film having these stretchability and characteristic values is stretched in the longitudinal stretching step 20 and the transverse stretching step 30.

Below, the extending | stretching process for extending | stretching the cellulose acylate film manufactured by the film forming process part 10 and manufacturing an extending | stretching cellulose acylate film is demonstrated.

Stretching of the cellulose acylate film 16 is performed in order to orient the molecules in the cellulose acylate film 16 to express the in-plane retardation and the retardation in the thickness direction. Here, the delays R e and R t are calculated by the following equation.

R (n) = | n (MD) -n (TD) | × T (ｎ)

Rth (ｎｍ) = | {(n (MD) + n (TD)) / 2} -n (TH) | × T (ｎ)

In the formula, n (MD), n (TD), and n (TH) represent refractive indexes in the longitudinal direction, the width direction, and the thickness direction, and T represents the thickness in nm.

As shown in FIG. 1, the cellulose acylate film 16 is first longitudinally stretched in the longitudinal direction by the longitudinal stretching step 20. In the longitudinal stretching step 20, after the cellulose acylate film 16 is preheated, the heated cellulose acylate film 16 is wound around two nip rolls 22, 24. The nip roll 24 on the outlet side conveys the cellulose acylate membrane 16 at a higher conveying speed than the nip roll 22 on the inlet side, whereby the cellulose acylate membrane 16 moves in the longitudinal direction. Stretched.

As for the preheating temperature in the longitudinal drawing process part 20, Tg-40 degreeC-Tg + 60 degreeC is preferable, Tg-20 degreeC-Tg + 40 degreeC is more preferable, and Tg-Tg + 30 degreeC is still more preferable. . As for the extending | stretching temperature of the longitudinal stretch process part 20, Tg-Tg + 60 degreeC is preferable, Tg + 2 degreeC-Tg + 40 degreeC is more preferable, and Tg + 5 degreeC-Tg + 30 degreeC is still more preferable. 1.01 times-3 times are preferable, as for the longitudinal stretch ratio, 1.05 times-2.5 times are more preferable, 1.1 times-2 times are more preferable.

The cellulose acylate film 16 stretched in the longitudinal direction is sent to the transverse stretching step 30 and transversely stretched in the width direction. In the horizontal stretching step 30, a tenter is suitably used, and both ends of the width direction of the cellulose acylate film 16 are gripped with a clip and stretched in the horizontal direction. By this transverse stretching, the delay rate can be further increased.

It is preferable to perform a lateral stretch using a tenter. As for a preferable extending | stretching temperature, Tg-Tg + 60 degreeC is preferable, More preferably, Tg + 2 degreeC-Tg + 40 degreeC, More preferably, Tg + 4 degreeC-Tg + 30 degreeC. Preferable draw ratio is 1.01 times-3 times, More preferably, they are 1.05 times-2.5 times, More preferably, they are 1.1 times-2 times. It is also preferable to relax to either or both of the length and the width after the horizontal stretching. Therefore, the distribution of the slow axis in the width direction can be made small.

By such stretching, R is preferably 0 nm to 500 nm, more preferably 10 nm to 400 nm, and more preferably 15 nm to 300 nm. RFT is 30 nm-500 nm, More preferably, it is 50 nm-400 nm, More preferably, it is 70 nm-350 nm.

Among these, it is preferable to satisfy R <= R <t> tele, More preferably, it satisfies [R <e> x <2> <= R <t> l. In order to realize such a high R and a low R, it is preferable to extend | stretch the film extended | stretched in the vertical (length) direction as mentioned above in the horizontal (width) direction. In other words, the difference in orientation in the longitudinal direction and in the transverse direction is the difference in in-plane retardation, R e, but also in the transverse direction in the orthogonal direction as well as in the longitudinal direction. can do. On the other hand, since the area magnification increases by stretching in the width direction along with the longitudinal direction, the orientation in the thickness direction increases as the thickness decreases, and the Rt is increased.

Moreover, all the fluctuation | variation by the place of the width | variety and the longitudinal direction of R e and R t is 5% or less, More preferably, it is 4% or less, More preferably, it is 3% or less.

As described above, according to this embodiment, by producing a stretched cellulose acylate film using the cellulose acylate film produced by the production method of the present invention, the drawing is hardly broken and a high draw ratio can be obtained, and at the same time, The fluctuation | variation by the place of the width direction and the longitudinal direction of Rt is small. Therefore, a stretched cellulose acylate film excellent in optical characteristics can be produced.

EMBODIMENT OF THE INVENTION Below, the film forming method of the cellulose acylate resin suitable for this invention, the unstretched cellulose acylate film, and the processing method of a cellulose acylate film are demonstrated in detail in order.

(Cellulose acylate resin)

It is preferable that the cellulose acylate used by this invention has the following characteristics.

A cellulose acylate film in which the acylate group satisfies the following degree of substitution (A represents the total substitution degree of the acetyl group, B represents the propionyl group, the butyryl group, the pentanoyl group, and the hexanoyl group).

2.5≤A + B <3.0

1.25≤B <3

More preferred substitution degree is that when at least 1/2 of B is a propionyl group,

2.6≤A + B≤ 2.95

2.0≤B≤ 2.95

If less than 1/2 of B is propionyl group,

2.6≤A + B≤ 2.95

1.3 ≦ B ≦ 2.5.

More preferred substitution degree is

If at least half of B is a propionyl group,

2.7≤A + B≤ 2.95

2.4≤B≤ 2.9

If less than 1/2 of B is propionyl group,

2.7≤A + B≤ 2.95

1.3? B? 2.0.

A feature of the present invention is that the degree of substitution of the acetyl group in the acyl group is reduced and the sum of the degree of substitution of propionyl group, butyryl group, pentanoyl group and hexanoyl group is increased. Therefore, it is possible to reduce the change of R e and R e T e in the elapsed time after stretching. This increases the flexibility of the membrane and increases the stretchability by increasing the number of these groups longer than the acetyl group. Therefore, the orientation of the cellulose acylate molecules is not easily disturbed by the stretching, and thus the time of the expression of R and R The change accordingly is reduced. However, when the acyl group is longer than the above, the glass transition temperature (Tg) and the elastic modulus are considerably reduced, which is undesirable. For this reason, the propionyl group, butyryl group, pentanoyl group, and hexanoyl group larger than an acetyl group are preferable, More preferably, they are propionyl group and butyryl group, More preferably, they are butyryl group.

The basic principle of the synthesis method of these cellulose acylates is described in Migita et al., Pp. 180-190 (public publication, 1968). A typical synthetic method is a liquid acetylation method using a carboxylic anhydride / acetic acid / sulfuric acid catalyst. Specifically, the raw material of cellulose such as cotton linter or wood pulp is pretreated with an appropriate amount of acetic acid, and then added to a pre-cooled carboxylic acid mixture, followed by esterification to complete cellulose acylate (2-position, 3-position and 6). The sum of the acyl substitution degree of a position synthesize | combines nearly 3.00). The carboxylic acid mixed solution generally contains acetic acid as a solvent, anhydrous carboxylic acid as an esterifying agent and sulfuric acid as a catalyst. Anhydrous carboxylic acid is usually used in an excess amount stoichiometrically than the sum total of the cellulose which reacts with this, and the water which exists in a system. After completion of the acylation reaction, a neutralizing agent (e.g., carbonate, acetate or carbonate of calcium, magnesium, iron, aluminum or zinc) is used to hydrolyze the excess anhydrous carboxylic acid remaining in the system and to neutralize some of the esterification catalyst. An aqueous solution of oxide) is added. The complete cellulose acylate obtained is then sensitized by holding at 50-90 ° C. in the presence of a small amount of acetylation catalyst, generally remaining sulfuric acid, and converted to cellulose acylate having the desired degree of acyl substitution and polymerization. do. The cellulose acylate solution is introduced into water or lean acid without neutralizing the desired cellulose acylate remaining in the system using the neutralizing agent as described above or neutralizing (or, in the cellulose acylate solution, water Or dilute acid) to separate cellulose acylate, and to obtain cellulose acylate by washing and stabilizing treatment.

The degree of polymerization of the cellulose acylate used preferably in the present invention is 200 to 700, preferably 250 to 550, more preferably 250 to 400, and particularly preferably 250 to 350. The average degree of polymerization of the viscosity can be measured by an intrinsic viscosity method other than Uda (Kazao Uda, Hideo Saito, Textile Society, Japan, Vol. 18, No. 1, pp. 105 to 120, 1962). It is further described in detail in Japanese Patent Laid-Open No. 9-95538.

Adjustment of the said viscosity average polymerization degree can be achieved by removing a low molecular weight component. If such a low molecular weight component is removed, the average molecular weight (polymerization degree) is increased, but the viscosity is useful because it is lower than the general cellulose acylate. The low molecular weight component can be removed by washing the cellulose acylate with a suitable organic solvent. The molecular weight can also be adjusted by the polymerization method. For example, when manufacturing the cellulose acylate with few low molecular weight components, it is preferable to adjust the amount of sulfuric acid catalysts of an acetylation reaction with respect to 0.5-25 mass parts with respect to 100 weight of cellulose. When the amount of sulfuric acid catalyst is in the above range, cellulose acylate which is preferable (even in molecular weight distribution) can be synthesized in terms of molecular weight distribution.

As for the cellulose acylate which can be used by this invention, it is preferable that weight average molecular weight Mk / number average molecular weight Mn ratio is 1.5-5.5, More preferably, it is 2.0-5.0, Especially preferably, it is 2.5-5.0, Most preferably Is 3.0 to 5.0.

These cellulose acylates may use only one type and may mix 2 or more types. You may use the mixture which mixed suitably polymeric components other than cellulose acylate. It is preferable that the polymeric component to be mixed is excellent in compatibility with a cellulose ester, and when it is set as a film | membrane, it is preferable that the transmittance | permeability is 80% or more, More preferably, it is 90% or more, More preferably, it is 92% or more.

In this invention, the crystal melting temperature (Tm) of a cellulose acylate can be reduced by adding a plasticizer to a cellulose acylate. The molecular weight of the plasticizer used for this invention is not specifically limited, A low quantity or a high molecular weight may be sufficient. Examples of the plasticizer include phosphoric acid esters, alkylphthalyl alkylglycolates, carboxylic acid esters, and fatty acid esters of polyhydric alcohols. The shape of the plasticizer may be solid or may be an oily substance. That is, the melting point and boiling point are not specifically limited. In the case of performing a melt film forming, a nonvolatile plasticizer is particularly preferably used.

Specific examples of the phosphate esters include, for example, triphenyl phosphate, tributyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, trioctyl phosphate, trinaphthyl phosphate, trixylyl phosphate, tris o-biphenyl phosphate, crease Silphenyl phosphate, octyldiphenyl phosphate, biphenyldiphenyl phosphate, 1,4-phenylenetetraphenyl phosphate and the like. Moreover, you may use the phosphate ester plasticizer of Claims 3-7 of Unexamined-Japanese-Patent No. 6-501040.

Examples of the alkylphthalyl alkylglycolates include methylphthalylmethylglycolate, ethylphthalylethylglycolate, propylphthalylpropylglycolate, butylphthalylbutylbutylglycolate, octylphthalyloctylglycolate and methylphthalyl. Ethylglycolate, ethylphthalylmethylglycolate, ethylphthalylpropylglycolate, methylphthalylbutylglycolate, ethylphthalylbutylglycolate, butylphthalylmethylglycolate, butylphthalylethylglycolate, propylphthalylbutyl Glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, an octyl phthalyl ethyl glycolate, etc. are mentioned.

Examples of the carboxylic acid esters include phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate and diethylhexyl phthalate, acetyl trimethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate. Adipic acid, such as citric acid ester, dimethyl adipate, dibutyl adipate, diisobutyl adipate, bis (2-ethylhexyl) adipate, diisodecyl adipate, and bis (butyl diglycol) adipate Aromatic polyhydric carboxylic acid esters such as esters, tetraoctyl pyromellitate, and trioctyl trimellitate, dibutyl adipate, dioctyl adipate, dibutyl sebacate, dioctyl sebacate, diethyl azelate Aliphatic polycarboxylic acid esters such as dibutyl azelate and dioctyl azelate , There may be mentioned glycerol triacetate, diglycerol tetraacetate, acetylated glyceride, monoglycerides, di-and polyhydric alcohol fatty acid esters such as glyceride or the like. In addition, you may use butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, triacetin, etc. individually or in combination.

In addition, aliphatic polyesters composed of glycols such as polyethylene adipate, polybutylene adipate, polyethylene succinate, and polybutylene succinate and dibasic acids, and aliphatic polyesters composed of oxy carboxylic acids such as polylactic acid and polyglycolic acid And high molecular weight plasticizers such as aliphatic polyesters composed of lactones such as polycaprolactone, polypropiolactone, and polyvalerolactone, and vinyl polymers such as polyvinylpyrrolidone. A plasticizer can be used individually or in combination with a low quantity plasticizer.

The polyhydric alcohol-based plasticizer has compatibility with cellulose fatty acid esters, and exhibits a remarkable thermal plasticizing effect. Polyalkylene glycols such as glycerol ester compounds such as glycerol esters and diglycerol esters, polyethylene glycols, and polypropylene glycols And a compound in which an acyl group is bonded to a hydroxyl group of polyalkylene glycol.

As specific glycerol esters, glycerol diacetate stearate, glycerol diacetate palmitate, glycerol diacetate myristate, glycerol diacetate laurate, glycerol diacetate caprate, glycerol diacetate nonanoate, glycerol diacetate octanoate, glycerol diacetate Diacetate heptanoate, glycerol diacetate hexanoate, glycerol diacetate pentanoate, glycerol diacetate oleate, glycerol acetate dicaprate, glycerol acetate dinonanoate, glycerol acetate dioctanoate, glycerol acetate diheptanoate, Glycerol Acetate Dicaproate, Glycerol Acetate Divalorate, Glycerol Acetate Dibutylate, Glycerol Dipropionate Carr Glycerol dipropionate laurate, glycerol dipropionate myristate, glycerol dipropionate palmitate, glycerol dipropionate stearate, glycerol dipropionate oleate, glycerol tributylate, glycerol tripenta Noate, glycerol monopalmitate, glycerol monostearate, glycerol distearate, glycerol propionate laurate, and glycerol oleate propionate, but are not limited thereto. These can be used alone or in combination.

Among these, glycerol diacetate caprylate, glycerol diacetate pelaronate, glycerol diacetate caprate, glycerol diacetate laurate, glycerol diacetate myristate, glycerol diacetate palmate, glycerol diacetate stearate, and glycerol diacetate Acetate oleate is preferred.

Specific examples of the diglycerol esters include diglycerol tetraacetate, diglycerol tetrapropionate, diglycerol tetrabutyrate, diglycerol tetravalerate, diglycerol tetrahexanoate, diglycerol tetraheptanoate and diglycerol tetracaprylate , Diglycerol tetrapelanate, diglycerol tetracaprate, diglycerol tetralaurate, diglycerol tetramyristate, diglycerol tetrapalmitate, diglycerol triacetate propionate, diglycerol triacetate butyrate, diglycerol triacetate Valerate, diglycerol triacetate hexanoate, diglycerol triacetate heptanoate, diglycerol triacetate caprylate, diglycerol triacetate pelaronate, diglycerol Acetate caprate, diglycerol triacetate laurate, diglycerol triacetate myristate, diglycerol triacetate palmitate, diglycerol triacetate stearate, diglycerol triacetate oleate, diglycerol diacetate dipropionate, diglycerol Diacetate dibutyrate, diglycerol diacetate devalorate, diglycerol diacetate dihexanoate, diglycerol diacetate diheptanoate, diglycerol diacetate dicaprylate, diglycerol diacetate dipellonate, diglycerol diacetate Dicaprate, Diglycerol Diacetate Dilaurate, Diglycerol Diacetate Dimyristate, Diglycerol Diacetate Dipalmitate, Diglycerol Diacetate Distearate, Di Glycerol Diacetate Dioleate, Diglycerol Acetate Tripropionate, Diglycerol Acetate Tributyrate, Diglycerol Acetate Trivalate, Diglycerol Acetate Trihexanoate, Diglycerol Acetate Triheptanoate, Diglycerol Acetate Tricaprylate , Diglycerol acetate tripelonate, diglycerol acetate tricaprate, diglycerol acetate trilaurate, diglycerol acetate trimyristate, diglycerol acetate tripalmitate, diglycerol acetate tristearate, diglycerol acetate trioleate Mixed esters of diglycerols such as diglycerol laurate, diglycerol stearate, diglycerol caprylate, diglycerol myristate, and diglycerol oleate Although these etc. are mentioned, it is not limited to these. These can be used alone or in combination.

Among these, diglycerol tetraacetate, diglycerol tetrapropionate, diglycerol tetrabutyrate, diglycerol tetracaprylate, and diglycerol tetralaurate are preferable.

Specific examples of the polyalkylene glycols include polyethylene glycols having an average molecular weight of 200 to 1000, polypropylene glycols, and the like, but are not limited to these, and these may be used alone or in combination.

As a specific example of the compound which the acyl group couple | bonded with the hydroxyl group of polyalkylene glycol, Polyoxyethylene acetate, polyoxyethylene propionate, polyoxyethylene butyrate, polyoxyethylene valerate, polyoxyethylene caproate, polyoxyethylene heptano Eight, polyoxyethylene octanoate, polyoxyethylene nonanoate, polyoxyethylene caprate, polyoxyethylene laurate, polyoxyethylene myristate, polyoxyethylene palmitate, polyoxyethylene stearate, polyoxyethylene oleate , Polyoxyethylene linoleate, polyoxypropylene acetate, polyoxypropylene propionate, polyoxypropylene butyrate, polyoxypropylene valerate, polyoxypropylene caproate, polyoxypropylene heptanoate, polyoxypropylene octanoate , Polyoxypropylene nonanoate, polyoxypropylene caprate, polyoxypropylene laurate, polyoxypropylene myristate, polyoxypropylene palmitate, polyoxypropylene stearate, polyoxypropylene oleate, and polyoxypropylene linoleate Although it may be mentioned, it is not limited. These can be used alone or in combination.

It is preferable that the addition amount of a plasticizer is 0-20 weight%, More preferably, it is 2-18 weight%, Most preferably, it is 4-15 weight%. When the content of the plasticizer is more than 20% by weight, the thermal fluidity of the cellulose acylate becomes good, but the plasticizer flows out onto the surface of the film of the melted agent, and the glass transition temperature Tg that is heat resistant is lowered.

Moreover, the cellulose acylate in this invention can add the stabilizer for heat deterioration prevention and coloring prevention as needed, within the range which does not impair the performance required.

As a stabilizer, you may add a phosphite type compound, a phosphite ester compound, a phosphate, a thiophosphate, a weak organic acid, an epoxy compound, etc. individually or in mixture of 2 or more types. As a specific example of a phosphite stabilizer, the compound of Paragraph [0023]-[0039] of Unexamined-Japanese-Patent No. 2004-182979 can be used preferably. Specific examples of the phosphorous acid ester compound include Japanese Patent Application Laid-Open No. 51-70316, Japanese Patent Application Laid-Open No. 10-306175, Japanese Patent Publication No. 57-78431, Japanese Patent Publication No. 54-157159, and Japanese Patent Publication No. 55- The compound described in 13765 can be used.

It is preferable that the addition amount of the stabilizer in this invention is 0.005-0.5 weight% with respect to cellulose acylate, More preferably, it is 0.01-0.4 weight%, More preferably, it is 0.05-0.3 weight%. When the added amount is less than 0.005% by weight, the effects of preventing deterioration and coloring at the time of melt film forming are insufficient, which is not preferable. On the other hand, when it is 0.5 weight% or more, it flows out into the surface of the cellulose acylate film | membrane formed into a film, and it is unpreferable.

Moreover, you may add deterioration inhibitor and antioxidant. By adding a phenolic compound, a thioether compound, or a phosphorus compound as a deterioration inhibitor or antioxidant, the synergistic effect of deterioration and antioxidant can be obtained. As other stabilizers, the materials described in detail on pages 17 to 22 of the Invention Association Publication (Publication No. 2001-1745, published March 15, 2001, Invention Association) can be preferably used.

Moreover, the cellulose acylate in this invention can contain a sunscreen, and may add 1 type, or 2 or more types of ultraviolet absorbers. It is preferable that the ultraviolet absorber for liquid crystals is excellent in the absorption ability of the ultraviolet-ray below wavelength 380nm from the viewpoint of the prevention of the deterioration of a liquid crystal, and the absorption of the visible light of wavelength 400nm or more is preferable from a viewpoint of liquid crystal display property. For example, an oxy benzophenone type compound, a benzotriazole type compound, a salicylic acid ester type compound, a benzophenone type compound, a cyano acrylate type compound, a nickel complex salt type compound, etc. are mentioned. Especially preferable ultraviolet absorbers are benzotriazole type compounds and benzophenone type compounds. Especially, a benzotriazole type compound is preferable because there is little undesired coloring with respect to a cellulose ester cellulose acylate, for example.

Preferred sunscreens include 2,6-di-ethret-butyl-p-cresol, pentaerythryl-tetrakis [3- (3,5-di-ethethyl-butyl-4-hydroxyphenyl) propionate], Triethyleneglycol-bis [3- (3- (telethan-butyl-5-methyl-4-hydroxyphenyl) propionate]], 1,6-hexanediol-bis [3- (3,5-di- (ethleitol)- Butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-pentethol-butyl anilino) -1,3 , 5-triazine, 2,2-thio-diethylene bis [3- (3,5-di-ethethyl-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5- Di- (eth) -butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di- (eth) -butyl-4-hydroxy-hydrocinnamid), 1,3,5 -Trimethyl-2,4,6-tris (3,5-di-pentethyl-butyl-4-hydroxybenzyl) benzene, and tris- (3,5-di-ethethyl-butyl-4-hydroxybenzyl)- Isocia There may be mentioned acrylate and the like.

In addition, 2,6-di-ethret-butyl-p-cresol, pentaerythryl-tetrakis [3- (3,5-di-ethethyl-butyl-4-hydroxyphenyl) propionate], and triethylene glycol -Bis [3- (3-tetrebutyl-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. In addition, hydrazine-based metal deactivators or tris (2,4-di-pentethyl), such as N, N'-bis [3- (3,5-di-ethethyl-butyl-4-hydroxyphenyl) propionyl] hydrazine You may use together phosphorus process stabilizers, such as butyl phenyl) phosphite. As for the addition amount of these compounds, 1-20 mass% is preferable at a mass ratio with respect to a cellulose ester, for example, a cellulose acylate, 10-10 mass% is more preferable.

The following commercially available things can be used for these ultraviolet absorbers.

The benzotriazole UV absorbers include TINUBIN P (Ciba Specialty Chemicals KK), TINUBIN 234 (Ciba Specialty Chemicals KK), TINUBIN 320 (Ciba Specialty Chemicals KK), TINUBIN 326 (Ciba Specialty Chemicals KK), and TINUBIN 327 (Ciba Specialty Chemicals KK) , TINUBIN 328 (Ciba Specialty Chemicals KK), and Sumisorb 340 (Sumitomo Chemical Co., Ltd.). As a benzophenone ultraviolet absorber, Seesorb 100 (SHIPRO KASEI KAISHA LTD.), Seesorb 101 (SHIPRO KASEI KAISHA LTD.), Seesorb 101S (SHIPRO KASEI KAISHA LTD.), Seesorb 102 (SHIPRO KASEI KAISHA LTD.), Seesorb 103 ( SHIPRO KASEI KAISHA LTD.), ADK STAB LA-51 (ASAHI DENKA CO., LTD.), Chemisorp 111 (CHEMIPRO KASEI KAISHA LTD.), And UVINUL D-49 (BASF). Oxalic acid anilide-based ultraviolet absorbers include TINUBIN 312 (Ciba Specialty Chemicals K.K) and TINUBIN 315 (Ciba Specialty Chemicals K.K). As the salicylic acid ultraviolet absorber, Seesorb 201 (SHIPRO KASEI KAISHA LTD.) And Seesorb 202 (SHIPRO KASEI KAISHA LTD.) Are commercially available, and as a cyano acrylate UV absorber, Seesorb 501 (SHIPRO KASEI KAISHA LTD.), And UVINUL N-539 (BASF).

It is preferable that the unstretched cellulose acylate film | membrane and stretched cellulose acylate film | membrane in this invention have the following R e and R e tether.

That is, it is preferable that the unstretched cellulose acylate membrane of the present invention satisfies R and R in the formula:

0≤Ｒｅ≤20

0≤Ｒｔｈ≤80

More preferably

0≤Ｒｅ≤15

0≤Ｒｔｈ≤70

More preferably

0≤Ｒｅ≤10

0≤Rｔｈ≤60.

The stretched cellulose acylate membrane of the present invention preferably satisfies R and R in the formula:

0≤Ｒｅ≤500

30≤Ｒｔｈ≤500

More preferably

10≤Ｒｅ≤400

50≤Ｒｔｈ≤400

More preferably

15≤Ｒｅ≤300

70≤Ｒｔｈ≤350

(Melt film)

(1) drying

Although cellulose acylate resin may be used as powder, it is more preferable to use pelletized resin in order to reduce the thickness variation of the film forming.

The cellulose acylate resin has a water content of 1% or less, more preferably 0.5% or less, more preferably 0.1% or less, and then is introduced into a hopper of the extruder. At this time, the temperature of the hopper is set to Tg-50 deg. C to Tg + 30 deg. C or less, more preferably Tg-40 deg. C to Tg + 10 deg. C, and more preferably Tg-30 deg. This suppresses the resorption of moisture in the hopper and can easily achieve the drying efficiency. In addition, dehydrated air or an inert gas (for example, nitrogen) may be introduced.

(2) kneading extrusion

190 degreeC-240 degreeC, More preferably, it is knead | mixed and fuse | melted at 195 degreeC-235 degreeC, More preferably, 200 degreeC-230 degreeC. At this time, the melting temperature may be performed at a constant temperature or may be divided into several zones and controlled. Preferable kneading time is 2 minutes-60 minutes, More preferably, they are 3 minutes-40 minutes, More preferably, they are 4 minutes-30 minutes. In addition, it is also preferable to carry out the inside of an extruder under inert (nitrogen etc.) airflow, or to vacuum-exhaust using the extruder with a vent.

(3) cast

The molten cellulose acylate resin is passed through the gear pump, the pulsation of the extruder 11 is removed, followed by filtration with a metal mesh filter or the like, and the cooling drum 14 through the T-shaped die 12 attached behind the filter. Extrude into sheet form. The resin may be extruded in a single layer, or may be extruded in a plurality of layers using a multi-manifold or a feed block die. At this time, the thickness nonuniformity of the width direction can be adjusted by adjusting the space | interval of the rib of the die 12. As shown in FIG.

Next, the resin is extruded onto the cooling drum 14. At this time, the adhesion between the cooling drum 14 and the melt-extruded sheet may be increased using a method such as an electrostatic application method, an air knife method, an air chamber method, a vacuum nozzle method, or a touch roll method. Such an adhesion improving method may be performed on the entire surface of the melt-extruded sheet, or may be performed on a part (for example, only at both ends).

As for the cooling drum 14, 60 to 160 degreeC is preferable, More preferably, it is 70 to 150 degreeC, More preferably, it is 80 to 140 degreeC. Next, the sheet is peeled off from the cooling drum 14 and wound up through the nip rolls 22 and 24 and the tenter. The winding speed is preferably 10 m / min to 100 m / min, more preferably 15 m / min to 80 m / min, more preferably 20 m / min to 70 m / min.

The film forming width is 1 m to 5 m, more preferably 1.2 m to 4 m, and more preferably 1.3 m to 3 m. 30 micrometers-400 micrometers are preferable, as for the thickness of the unstretched cellulose acylate film obtained in this way, More preferably, they are 40 micrometers-300 micrometers, More preferably, they are 50 micrometers-200 micrometers.

It is preferable that the cellulose acylate film 16 thus obtained is trimmed at both ends and wound up by the winder 40 once. The part prepared after trimming may be reused as a raw material for cellulose acylate membranes of the same or different varieties after being pulverized or subjected to granulation treatment, depolymerization or repolymerization as necessary. Moreover, it is also preferable from a viewpoint of a scratch prevention to stick a laminated film on at least one surface before winding up.

The glass transition temperature (Tg) of the cellulose acylate film thus obtained is preferably 70 ° C to 180 ° C, more preferably 80 ° C to 160 ° C, and more preferably 90 ° C to 150 ° C.

(Processing of Cellulose Acylate Film)

The cellulose acylate membrane formed into a film by the said method is extended | stretched uniaxially or biaxially by the said method, and an oriented cellulose acylate membrane is manufactured. These may be used independently, may be used combining these and a polarizing plate, and may form and use the liquid crystal layer and the layer (low reflection layer) which controlled the refractive index, and the hard-coat layer on these. These can be achieved by the following steps.

(1) surface treatment

By surface-treating a cellulose acylate film, adhesion | attachment with each functional layer (for example, a lower coating layer and a white layer) can be improved. For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, and acid or alkali treatment can be used. In this case, the glow discharge treatment may be a low-temperature plasma generated under a low pressure gas of 10 ^-3 to 10 ^-20 Tare or a plasma treatment under atmospheric pressure. The plasma excited gas means a gas that is plasma excited under the above conditions, and examples thereof include argon, helium, neon, krypton, xeon, nitrogen, carbon dioxide, chlorofluorocarbons such as tetrafluoromethane, and mixtures thereof. have. These details are described in detail on pages 30 to 32 of the Invention Association Publication (Publication 2001-1745, published March 15, 2001, Invention Association). Moreover, the plasma treatment under atmospheric pressure which is attracting attention recently can use irradiation energy of 20-500 GPGxy at 10-1000 Pa, for example, More preferably, 20-300 GPY irradiation energy can be used under 30-500 KPa.

Among these, especially preferably, it is an alkali saponification process.

An alkali saponification process may be immersed in the saponification liquid (immersion method), and may be apply | coated with a saponification liquid (coating method). In the case of the immersion method, it can achieve by carrying out the tank heated to 20 degreeC-80 degreeC aqueous solution of NH10-14, such as NAOH and JOH, from 0.1 minute to 10 minutes, and then neutralizing, washing with water, and drying.

In the case of the coating method, a dip coating method, a curtain coating method, an extrusion molding method, a bar coating method and an E type coating method can be used. The solvent of the alkali saponification coating liquid is preferably selected from a solvent having excellent hygroscopicity suitable for applying the sensitizing liquid to the transparent support and capable of maintaining good surface conditions without forming irregularities on the surface of the transparent support. Specifically, an alcoholic solvent is preferable and isopropyl alcohol is especially preferable. Moreover, the aqueous solution of surfactant can also be used as a solvent. Alkali which can melt | dissolve in the said solvent as alkali of the alkali saponification liquid is preferable, JOH and NAOH are more preferable. 10 or more are preferable and, as for the pH of the sacrificial coating liquid, 12 or more are more preferable. 1 second-5 minutes are preferable at room temperature, as for reaction conditions at the time of alkali reduction, 5 seconds-5 minutes are more preferable, 20 second-3 minutes are especially preferable. After the alkali sensitization reaction, the surface coated with the sensitizer may be washed with water or acid and washed with water. A coating type reduction process and application | coating of the orientation film mentioned later can be performed continuously, and the number of processes can be reduced. Specific examples of these methods include description of contents in Japanese Patent Laid-Open Nos. 2002-82226 and 02/46809.

In order to adhere | attach with a functional layer, you may provide a lower coating layer. This layer may be applied after the surface treatment or may be applied and formed without surface treatment.

Details of the lower coating layer are described on page 32 of the Invention Association Publication (Publication No. 2001-1745, published March 15, 2001, Invention Association).

These surface treatment and lower coating process may be included last in a film forming process, may be performed independently, and may be performed in the functional layer provision process mentioned later.

(Granting of functional layer)

The cellulose acylate membrane of the present invention may be used in combination with the functional layer described in detail on pages 32 to 45 of the Society of the Invention Publication (Publication No. 2001-1745, issued March 15, 2001, Invention Association). good. Especially preferable are provision of a polarizing layer (polarizing plate), provision of a compensation layer (compensation sheet), and provision of an antireflection layer (antireflection film).

(A) Provision of a polarizing layer (production of a polarizing plate)

25-350 micrometers is preferable, as for the thickness of the protective film of a polarizing film, More preferably, it is 30-200, More preferably, it is 40-120 micrometers. When using as a protective film of a polarizing film, the cellulose acylate film of this invention can use both an unstretched film or a stretched film. The stretched cellulose acylate film of this invention can be used as a protective film function of a polarizing film, and it is also preferable to use as retardation compensation film.

The obtained polarizing plate may have the following structures.

Polarizing plate A: unstretched cellulose acylate film / polarizing film / FUJITAC

Polarizing Plate B: Unoriented Cellulose Acylate Film / Polarizing Film / Unoriented Cellulose Acylate Film

Polarizing plate C: Stretched cellulose acylate film / polarizing film / FUJITAC

Polarizing plate D: Stretched cellulose acylate film / polarizing film / unstretched cellulose acylate film

Polarizing plate E: Stretched cellulose acylate film / polarizing film / stretched cellulose acylate film

(A-1) Use material

At present, it is common to produce a commercially available polarizing layer by immersing the stretched polymer in a solution of iodine or dichroic dye in a bath and infiltrating iodine or dichroic dye in a binder. As a polarizing film, the coating type polarizing film represented by Optiva Inc. can also be used. Iodine and dichroic dye in a polarizing film are oriented in a binder and the deflection performance is expressed. As the dichroic dye, an azo dye, a stilbene dye, a parazolone dye, a triphenylmethane dye, a quinoline dye, an oxazine dye, a thiazine dye or an anthraquinone dye can be used. Water-soluble dichroic pigments are preferred. It is preferable that such dichroic dye contains a hydrophilic substituent (for example, sulfo, amino, hydroxyl). For example, the compound of the invention association publication technique, Unexamined-Japanese-Patent No. 2001-1745, page 58 (published March 15, 2001) is mentioned.

As the binder of the polarizing film, a polymer which is itself crosslinkable, a polymer crosslinked in the presence of a crosslinking agent, or a combination thereof can be used. Examples of the binder include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohols and modified polyvinyl alcohols, and poly (N-meth) as described in paragraph [0022] of the specification of JP-A 8-338913. Tyrolacrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethylcellulose, and polycarbonate. Silane coupling agents can be used as such polymers. Among them, water-soluble polymers (e.g., poly (N-methyrolacrylamide), carboxymethyl cellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, and gelatin, polyvinyl alcohol and modified polyvinyl alcohol are preferred. More preferably, polyvinyl alcohol and modified polyvinyl alcohol are most preferred. It is especially preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohols with different degrees of polymerization. 70-100% is preferable and, as for the influence degree of polyvinyl alcohol, 80-100% is more preferable. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5,000. The modified polyvinyl alcohol is described in each publication of Japanese Patent Application Laid-Open Nos. 8-338913, 9-152509 and 9-316127. You may use together 2 or more types of polyvinyl alcohol and modified polyvinyl alcohol.

It is preferable that the minimum of binder thickness is 10 micrometers. The upper limit of the thickness is preferably as thin as possible from the viewpoint of light leakage of the liquid crystal display element. It is preferable that it is currently a commercially available polarizing plate (about 30 micrometers or less), 25 micrometers or less are preferable, and 20 micrometers or less are more preferable.

The binder of the polarizing film may be crosslinked. The polymer or monomer having a crosslinkable functional group may be mixed in the binder, or the crosslinkable functional group may be added directly to the binder polymer. Crosslinking can be bridge | crosslinked by light, heat, or pH change, and can form the binder which has a crosslinked structure. Crosslinking agents are described in the specification of US Reissue Patent 23297. Boron compounds (eg, boric acid, borax) can also be used as the crosslinking agent. As for the addition amount of the crosslinking agent of a binder, 0.1-20 mass% is preferable with respect to a binder. In this step, the orientation of the polarizer and the heat and moisture resistance of the polarizer are improved.

Even after the crosslinking reaction is completed, the unreacted crosslinking agent is preferably 1.0 mass% or less, and more preferably 0.5 mass% or less. This improves weather resistance.

(A-2) Stretching of the polarizing layer

It is preferable to dye | stain a polarizing film with iodine or a dichroic dye after extending | stretching (stretching method) or rubbing (rubbing method).

In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. The stretching may be performed by dry stretching in the air or wet stretching in a state immersed in water. The stretching ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretching ratio of wet stretching is preferably 3.0 to 10.0 times.

The film may be stretched parallel to the machine direction (parallel stretching) or may be stretched in an oblique direction (inclined stretching). You may extend | stretch once or several times. By extending | stretching several times, even when extending | stretching at high magnification, it can extend | stretch uniformly.

a) parallel drawing

Before stretching, the PAA film is swollen. The degree of swelling is 1.2 to 2.0 times (weight ratio before swelling and after swelling). Subsequently, stretching is carried out at 15 to 50 ° C., more preferably at 17 to 40 ° C. in a dye bath containing an aqueous medium bath or a dichroic substance dissolved while continuously conveyed by a guide roll. Stretching can be achieved by holding a film by two nip rolls, and making the conveyance speed of a nip roll of a rear end faster than the conveyance speed of a front end. The draw ratio is the length ratio (same as below) of the post-stretch / initial state, and the draw ratio which is more preferable than the point of the said effect is 1.2-3.5 times, More preferably, it is 1.5-3.0 times. The said film is dried at 50 degreeC from 90 degreeC, and a polarizing film is obtained.

b) gradient drawing

About this extending | stretching, the method of extending | stretching using the tenter projected in the diagonal direction described in Unexamined-Japanese-Patent No. 2002-86554 can be used. Since this stretching is performed in the air, it is necessary to make the stretching easier by making it water in advance. Preferable moisture content is 5%-100%, More preferably, it is 10%-100%.

40 degreeC-90 degrees C or less are preferable, and, as for the temperature at the time of extending | stretching, More preferably, it is 50 degreeC-80 degreeC. Humidity is preferably 50% RH to 100% R, more preferably 70% R to 100% R, more preferably 80% R to 100% R. As for the advancing speed of a longitudinal direction, 1 m / min or more is preferable, More preferably, it is 3 m / min or more. It is preferable to dry at 50 degreeC-100 degreeC after completion | finish of extending | stretching, More preferably, it is 0.5 to 10 minutes drying at 60 to 90 degreeC, More preferably, it is 1 to 5 minutes.

The absorption axis of the polarizing film thus obtained is preferably 10 degrees to 80 degrees, more preferably 30 degrees to 60 degrees, and more preferably substantially 45 degrees (40 degrees to 50 degrees).

(A-3) Adhesion

The said cellulose acylate film | membrane and the polarizing layer prepared by extending | stretching are bonded together, and the polarizing plate is prepared. It is preferable to adhere | attach so that the adhesion direction of the flexible axial direction of a cellulose acylate film and the extending | stretching axial direction of a polarizing plate may be 45 degree | times.

Although the adhesive agent for adhesion | attachment is not specifically limited, PVA type resin (including modified PFA such as an aceto acetyl group, a sulfonic acid group, a carboxyl group, or an oxy alkylene group), boron compound aqueous solution, etc. are mentioned. Among them, PPA-based resins are preferable. The adhesive layer thickness is preferably 0.01 to 10 m, particularly preferably 0.05 to 5 m after drying.

It is preferable that the light transmittance of the polarizing plate obtained in this way is high, and its polarization degree is high. The light transmittance of the polarizing plate with respect to light having a wavelength of 550 nm is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and most preferably in the range of 40 to 50%. It is preferable that the degree of polarization is in the range of 90 to 100%, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100% with respect to light having a wavelength of 550 nm.

The polarizing plate obtained in this way can be laminated | stacked with the (lambda) / 4 plate, and can manufacture circularly polarized light. In this case, the angle between the slow axis of (lambda) / 4 and the absorption axis of a polarizing plate is laminated so that it may be 45 degree | times. [Lambda] / 4 used herein is not particularly limited, but it is more preferable to have a wavelength dependency such that the smaller the wavelength, the smaller the delay. Moreover, it is preferable to use the (lambda) / 4 plate which consists of a polarizing film in which the absorption axis was 20 degrees-70 degrees with respect to the vertical direction, and the optically anisotropic layer which consists of a liquid crystalline compound.

(B) Provision of a compensation layer (production of a compensation sheet)

The compensation layer is produced by compensating for the liquid crystal compound in the liquid crystal cell when displaying black color of the liquid crystal display element, forming an alignment film on the cellulose acylate film, and applying an optically anisotropic layer thereon.

(B-1) alignment film

An alignment film is formed on the surface-treated cellulose acylate film. This alignment film has a function of defining the alignment direction of liquid crystal molecules. However, when the alignment state is fixed after the alignment of the liquid crystal compound, the alignment film is no longer a component of the present invention because the alignment film has completed its role. That is, it is also possible to manufacture the polarizing plate of this invention by transferring only an optically anisotropic layer to a polarizer in a fixed orientation state formed on the alignment film.

The alignment film is an organic compound (e.g., ω-trichoic acid) by rubbing treatment of an organic compound (preferably a polymer), evaporation of an inorganic compound, formation of a layer having micro grooves, or by a Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, and methyl stearate). Moreover, the orientation film which an orientation function produces by provision of an electric field, provision of a magnetic field, or light irradiation is also known.

It is preferable to form an alignment film by performing a rubbing process to a polymer. The polymer used for an oriented film has a molecular structure which can orientate liquid crystalline molecule in principle.

In the present invention, in addition to the function of orienting the liquid crystalline molecules, a side chain having a crosslinkable functional group (eg, a double bond) may be bonded to the main chain, or a crosslinkable functional group capable of orientating the liquid crystalline molecules may be introduced into the side chain. .

The polymer used for the alignment film may be a polymer itself crosslinkable or a polymer crosslinked by a crosslinking agent or a combination thereof. As such a polymer, for example, the methacrylate copolymer, styrene copolymer, polyolefin, polyvinyl alcohol, modified polyvinyl alcohol, poly (N-meth) described in paragraph No. 0022 of the specification of Japanese Patent Application Laid-Open No. 8-338913 Tyrolacrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethylcellulose, polycarbonate, and the like. Silane coupling agents can be used as such polymers.

Of these, water-soluble polymers (e.g., poly (N-methyrolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol) are preferred, and gelatin, polyvinyl alcohol, and modified polyvinyl alcohol More preferred is polyvinyl alcohol and modified polyvinyl alcohol. It is especially preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohols with different degrees of polymerization. 70-100% is preferable and, as for the influence degree of polyvinyl alcohol, 80-100% is more preferable. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5,000.

The side chain which has the function of orienting liquid crystalline molecules generally has a hydrophobic group as a functional group. The kind of specific functional group is determined according to the kind of liquid crystalline molecule and the orientation state required. The modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of the modified group include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, hydrocarbon groups having a fluorine atom substitution, thioether groups, and polymerization. And alkoxy silyl groups (trialkoxysilyl, dialkoxysilyl, monoalkoxysilyl), and the like (for example, unsaturated polymerizable groups, epoxy groups, and aziridinyl groups). As a specific example of these modified polyvinyl alcohol compounds, Paragraph No. 0022-0145 in the specification of Unexamined-Japanese-Patent No. 2000-155216, and Paragraph No. 0018-0022 in the specification of 2002-62426 are described, for example.

When a side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer or a crosslinkable functional group having a function of orienting liquid crystal molecules in the side chain is introduced, the polymer of the alignment film is copolymerized with the polyfunctional monomer contained in the optically anisotropic layer. Can be. As a result, not only the polyfunctional monomer itself, but also the alignment film polymer itself and also the polyfunctional monomer and the alignment film polymer are firmly bonded through a covalent bond. Therefore, the strength of the compensation sheet can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.

It is preferable that the crosslinkable functional group of an oriented film polymer contains a polymeric group like a polyfunctional monomer. Specifically, Paragraph No. 0080-0100 in the specification of Unexamined-Japanese-Patent No. 2000-155216 is described, for example. The alignment film polymer may be crosslinked using a crosslinking agent separately from the above crosslinkable functional groups.

Such crosslinking agents include aldehydes, N-metholol compounds, dioxane derivatives, compounds acting by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazoles and dialdehyde starches. You may use together 2 or more types of crosslinking agents. Specifically, Paragraph No. 0023-the compound of 0024 in the specification of Unexamined-Japanese-Patent No. 2002-62426, etc. are mentioned, for example. Aldehydes having high reaction activity, particularly glutaraldehyde, are preferred.

0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. It is preferable that it is 1.0 mass% or less, and, as for the quantity of the unreacted crosslinking agent which remains in an oriented film, it is more preferable that it is 0.5 mass% or less. By adjusting in this way, even if it is used for a long time in a liquid crystal display element or it is left to stand in a high temperature, high humidity atmosphere for a long time, network structure will not generate | occur | produce and sufficient durability can be obtained.

The alignment film can be basically formed by applying a solution containing the polymer as the alignment film forming material and a crosslinking agent onto the transparent support, followed by heat drying (crosslinking) and rubbing treatment. As mentioned above, after apply | coating on a transparent support body, you may perform crosslinking reaction at arbitrary times. When water-soluble polymers, such as polyvinyl alcohol, are used as an orientation film formation material, it is preferable that a coating liquid is a mixture of the organic solvent (for example, methanol) which has an antifoaming effect, and water. As for the ratio of water to methanol, 0: 100-99: 1 are preferable by mass ratio, and it is more preferable that it is 0: 100-91: 9. This suppresses the generation of bubbles and can significantly reduce the defect of the alignment film on the surface of any anisotropic layer.

The coating method of the alignment film is preferably a spin coating method, a dip coating method, a curtain coating method, an extrusion coating method, a rod coating method or a roll coating method, and among these, a rod coating method is particularly preferable. As for the film thickness after drying, 0.1-10 micrometers is preferable. Heat drying can be performed at 20 degreeC-110 degreeC. In order to obtain sufficient crosslinking, as for drying temperature, 60 degreeC-100 degreeC is preferable, and 80 degreeC-100 degreeC is especially preferable. Generally, drying time is 1 minute-36 hours, Preferably they are 1 minute-30 minutes. In addition, it is preferable to set the pH to an optimal value with respect to the crosslinking agent to be used, and when glutaraldehyde is used as a crosslinking agent, it is pH 4.5-5.5, Especially pH 5.0 is preferable.

The alignment film is formed on the transparent support or on the lower coating layer. The alignment film can be obtained by crosslinking the polymer layer described above and then rubbing the surface.

The rubbing treatment can be applied to a treatment method widely used in LC liquid crystal alignment treatment steps. More specifically, the method of obtaining an orientation can be used by rubbing the surface of an oriented film in a fixed direction using paper, a gauze, a felt, rubber, nylon, or polyester fiber. Generally, it carries out by rubbing about several times using the cloth which equally implanted the fiber of the same length and diameter.

When performing a rubbing process industrially, the said process is performed by contacting the film | membrane which the polarizing layer adhered and the rotating rubbing roll which are conveyed. It is preferable that the roundness, cylinder degree, and vibration (eccentricity) of the rubbing roll are all 30 µm or less. As for the wrap angle of the film | membrane to a rubbing roll, 0.1 degrees-90 degrees are preferable. However, as described in Japanese Patent Application Laid-Open No. Hei 8-160430, a stable rubbing treatment can also be achieved by winding a film around a roll of 360 ° or more. As for the conveyance speed of a film | membrane, 1-100 m / mIN is preferable. It is preferable to select a suitable rubbing angle in the range of 0-60 degrees of a rubbing angle (edge). When using the said film | membrane for a liquid crystal display element, 40-50 degrees are preferable and 45 degrees are especially preferable.

It is preferable that the film thickness of the orientation film obtained in this way exists in the range of 0.1-10 micrometers.

The liquid crystalline molecules of the optically anisotropic layer are oriented on the alignment layer. Thereafter, if necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer are reacted, or the alignment film polymer is crosslinked using a crosslinking agent.

Examples of the liquid crystalline molecules used for the optically anisotropic layer include rod-like liquid crystalline molecules and discotic liquid crystalline molecules. The rod-like liquid crystalline molecules and the discotic liquid crystalline molecules may be high molecular liquid crystals or low molecular liquid crystals, and may also include those in which the low molecular liquid crystals are crosslinked so as not to exhibit liquid crystallinity.

(B-2) Rod-shaped liquid crystalline molecules

As rod-shaped liquid crystalline molecule, azomethine, azoxy compound, cyano biphenyl, cyano phenyl ester, benzoic acid ester, cyclohexane carboxylic acid phenyl ester, cyano phenyl cyclohexane, cyano substitution Phenyl pyrimidines, alkoxy substituted phenyl pyrimidines, phenyl dioxanes, tolan compounds and alkenylcyclohexylbenzonitoryls are preferably used.

A metal complex may be sufficient as rod-shaped liquid crystalline molecule. A liquid crystal polymer containing a rod-like liquid crystalline molecule in a repeating unit can be used as the rod-like liquid crystalline molecule. That is, the rod-like liquid crystalline molecules may be bonded to the (liquid crystal) polymer.

For the rod-shaped liquid crystalline molecules, the liquid crystal device handbook of the Japanese Chemical Society, Volume 22, "Chemical Chemistry of Liquid Crystals (1994)", Chapters 4, 7 and 11, and Japan Society for the Promotion of the Society 142. See Chapter 3.

It is preferable that the birefringence of the rod-shaped liquid crystalline molecules is in the range of 0.001 to 0.7. The rod-like liquid crystal molecules may contain a polymerizable group in order to fix the alignment state. The polymerizable group is preferably a radical polymerizable unsaturated group or a cationic polymerizable group. Specifically, the polymeric group of Paragraph No. 0064-0086 in the specification of Unexamined-Japanese-Patent No. 2002-62427, and a polymeric liquid crystal compound are mentioned, for example.

(B-3) Discotic liquid crystalline molecule

Discoidal liquid crystalline molecules include C.Deestreferees' research report, MOC. Benzene Derivatives, Vol. 71, p. 1981 (1981), Research Report of C. Deferries, Metho. The trucsen derivatives described in Vol. 122, p. 141 (1985), and P. vol., Vol. 78, p. 82 (1990); 연구 ．Ｋｏｈｎｅ Research Reports, Ａｎｇｅｗ．Ｃｈｅｍ．Soc. 96, p. 70 (1984), cyclohexane derivatives and the research report of M.LÉｈ ones, M.Cｈｅｍ．Ｃｏｍｍｕｎ. , 1794 (1985), Ｊ．Research Report of Ｚｈａｎｇ, Ｊ．Ａｍ．Ｃｈｅｍ．Ｓｏｃ. Aza crown-based or phenylacetylene-based macro cycles described in Volume 116, page 2655 (1994).

Examples of the discotic liquid crystalline molecule include compounds showing liquid crystallinity, in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are substituted with a side chain in a radial form with respect to the parent nucleus located in the molecular center. It is preferable that a molecule | numerator or an aggregate of molecules is a compound which has rotational symmetry and can give a fixed orientation. The optically anisotropic layer formed from discotic liquid crystalline molecules does not necessarily have to be a discotic liquid crystalline molecule in which the compound finally contained in the optically anisotropic layer is contained, for example, containing a group in which the low molecular discotic liquid crystalline molecules react to heat or light. The compound which superposed | polymerized or bridge | crosslinked and the molecular weight increased as a result and lost liquid crystallinity is mentioned. Preferred examples of discotic liquid crystalline molecules are described in Japanese Patent Application Laid-open No. Hei 8-50206. The polymerization of discotic liquid crystalline molecules is described in Japanese Patent Laid-Open No. 8-27284.

In order to fix a discotic liquid crystalline molecule by superposition | polymerization, it is necessary to couple a polymeric group as a substituent to the discotic core of a discotic liquid crystalline molecule. The disk-shaped core and the polymerizable group are preferably a compound which is bonded via a linking group, and the structure can maintain the alignment state even in the polymerization reaction. For example, Paragraph No. 0151 of Unexamined-Japanese-Patent No. 2000-155216-the compound of 0168 can be mentioned.

In the hybrid orientation, the angle between the major axis (discrete surface) of the discotic liquid crystalline molecules and the surface of the polarizing film increases or decreases as the distance from the surface of the polarizing film increases in the depth direction of the optically anisotropic layer. The angle preferably increases or decreases as the distance increases. Also, as the change in angle, a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, and an intermittent change including an increase and a decrease are possible. The intermittent change includes a region where the tilt angle does not change in the thickness direction. Although it contains the area | region which an angle does not change, it should just increase or decrease as a whole. In addition, the angle is preferably continuously changed throughout.

The average direction of the major axis of the discotic liquid crystalline molecules on the polarizing film side can generally be adjusted by selecting the material of the discotic liquid crystalline molecules or the alignment film or by selecting a rubbing treatment method. The major axis (displacement) direction of the discotic liquid crystalline molecules on the surface side (air side) can generally be adjusted by selecting the type of additive to be used together with the discotic liquid crystalline molecules or discotic liquid crystalline molecules. As an example of the additive used with a discotic liquid crystalline molecule, a plasticizer, surfactant, a polymerizable monomer, a polymer, etc. are mentioned. Moreover, the grade of the change of the orientation direction of a long axis can also be adjusted by selection of a liquid crystalline molecule and an additive as mentioned above.

(B-4) Another composition of the optically anisotropic layer

Along with the above liquid crystal molecules, a plasticizer, a surfactant, or a polymerizable monomer may be used in combination, and the uniformity of the coating film, the strength of the film, the orientation of liquid crystal molecules, and the like may be improved. It is preferable that these components have compatibility with liquid crystalline molecules, and do not change the inclination angle of the liquid crystalline molecules or inhibit the orientation.

The polymerizable monomer may be a radical polymerizable or cationically polymerizable compound, preferably a polyfunctional radical polymerizable monomer, and preferably copolymerizable with a liquid crystal compound containing the polymerizable group. For example, Paragraph No. 0018 of the specification of Unexamined-Japanese-Patent No. 2002-296423-0020 can be mentioned. It is preferable that the addition amount of the said compound exists in the range of 1-50 mass% generally with respect to disk-like liquid crystalline molecule, and exists in the range of 5-30 mass%.

Although a conventionally well-known compound is mentioned as surfactant, Especially a fluorine-type compound is preferable. Specifically, the compound of Paragraph No. 0028-0056 in the specification of Unexamined-Japanese-Patent No. 2001-330725 is mentioned, for example.

It is preferable that the polymer used with a discotic liquid crystalline molecule can change the inclination angle of the discotic liquid crystalline molecule.

As an example of a polymer, a cellulose ester is mentioned. As a preferable example of a cellulose ester, the thing of Paragraph No. 0178 in the specification of Unexamined-Japanese-Patent No. 2000-155216 is mentioned. It is preferable to exist in the range of 0.1-10 mass% with respect to liquid crystalline molecule, and, as for the addition amount of the said polymer so that the orientation of liquid crystalline molecules is not impaired, it is more preferable to exist in the range which is 0.1-8 mass%.

70-300 degreeC is preferable and, as for the transition temperature of a solid phase from a disocortic nematic liquid crystal phase, 70-170 degreeC is more preferable.

(B-5) Formation of Optically Anisotropic Layer

An optically anisotropic layer can be formed by apply | coating the coating liquid containing liquid crystalline molecule and the polymeric initiator mentioned later or arbitrary components as needed on an oriented film.

As a solvent used for preparation of a coating liquid, an organic solvent is used preferably. Examples of the organic solvent include amide (e.g., N, N-dimethylformamide), sulfoxide (e.g., dimethyl sulfoxide), heterocyclic compound (e.g., pyridine), hydrocarbon (e.g., benzene, hexane), alkyl halide ( Eg chloroform, dichloromethane, tetrachloroethane), esters (eg methyl acetate, butyl acetate), ketones (eg acetone, methylethylketone), and ethers (eg tetrahydrofuran, 1,2-dimethoxyethane ). Of these, alkyl halides and ketones are preferred. You may use together 2 or more types of organic solvents.

Application | coating of a coating liquid can be performed by a well-known method (for example, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

It is preferable that the thickness of an optically anisotropic layer is 0.1-20 micrometers, It is more preferable that it is 0.5-15 micrometers, It is most preferable that it is 1-10 micrometers.

(B-6) Fixation of the Orientation State of Liquid Crystal Molecules

The aligned liquid crystal molecules can be fixed while maintaining the alignment state. It is preferable to perform fixation by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, and a photopolymerization reaction is preferable.

Examples of photopolymerization initiators include α-carbonyl compounds (described in the US Pat. Nos. 2,367,661 and US Pat. No. 2,367,670), acyloinether (described in the US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics Acyloin compound (described in the specification of US Pat. No. 2,722,512), multinucleated quinone compound (described in each specification of US Pat. No. 3,046,127, and US Pat. No. 2,951,758), with triarylimidazole dimers and p-aminophenylketone Combinations (described in US Pat. No. 3,549,367), acridine or phenazine compounds (described in JP 60-105667, and US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,212,970) Listed in the above).

It is preferable to exist in the range of 0.01-20 mass% of solid content of a coating liquid, and, as for the usage-amount of a photoinitiator, it is more preferable to exist in the range of 0.5-5 mass%.

In view of light irradiation for polymerization of the liquid crystalline molecules, it is preferable to use ultraviolet rays.

The irradiation energy is preferably in the range of 20 mPa / cm ² to 50 J / cm ² , more preferably in the range of 20 to 5000 mPa / cm ² , and even more preferably in the range of 100 to 800 mPa / cm ² . . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.

You may form a protective layer on an optically anisotropic layer.

You may combine this optical compensation film and a polarizing layer. Specifically, the optically anisotropic layer is formed by applying the above-described coating liquid for optically anisotropic layer to the surface of the polarizing film. As a result, a thin polarizing plate having a small stress (strain force × cross-sectional area × elastic modulus) due to the dimension change of the polarizing film can be produced without using any polymer film between the polarizing film and the optically anisotropic layer. When the polarizing plate of the present invention is attached to a large liquid crystal display element, problems such as light leakage do not occur, and an image having high display quality can be displayed.

It is preferable to extend | stretch so that the inclination-angle of a polarizing layer and an optical compensation layer may match to the angle between the transmission axis of the two polarizing plates stuck to the both sides of the liquid crystal cell which comprises LC, and the longitudinal or horizontal direction of a liquid crystal cell. Although the general inclination angle is 45 °, recently, transmissive, reflective and semi-transmissive LCDs, which are not necessarily 45 °, have been developed, and it is preferable that the stretching direction can be arbitrarily adjusted according to the design of the LCD.

(B-7) liquid crystal display element

Each liquid crystal mode which can use such an optical compensation film is demonstrated.

(TN mode liquid crystal display element)

This is most often used for color TFT liquid crystal display elements and has been described in a number of documents. In the alignment state in the liquid crystal cell in the black display of the TN mode, the rod-like liquid crystal molecules are vertically arranged in the cell center portion, while the rod-like liquid crystal molecules are horizontally aligned in the vicinity of the substrate of the cell.

(OCC mode liquid crystal display element)

In this mode, it is a liquid crystal cell of band alignment mode which orients the rod-shaped liquid crystalline molecules to the upper and lower portions of the liquid crystal cell substantially in the reverse direction (symmetrically). Liquid crystal display devices using such a liquid crystal cell in a band alignment mode are disclosed in the specifications of US Pat. No. 4,583,825 and US Pat. No. 5,410,422. Since the rod-like liquid crystalline molecules are symmetrically aligned with the upper and lower portions of the liquid crystal cell, the liquid crystal cell in the band alignment mode has a magneto-optic compensation function. This liquid crystal mode is also referred to as OCP (Optically Compensatory Bend) liquid crystal mode.

In the liquid crystal cell of the OCC mode, as in the TN mode, the bar-like liquid crystal molecules are vertically arranged in the cell center portion, and the bar liquid crystal molecules are horizontally aligned in the cell vicinity.

(BAA liquid crystal display element)

In the case where no voltage is applied, the rod-like liquid crystalline molecules are oriented substantially vertically. The liquid crystal cell of BA mode (1) liquid crystal cell of narrow bar mode which orientates a rod-shaped liquid crystalline molecule substantially vertically when a voltage is not applied, whereas it aligns substantially horizontally when a voltage is applied. (Japanese Patent Laid-Open No. 2-176625), (2) A liquid crystal cell (SI97, Digest of tech.Papers (SDI 97) in a mode in which the BA mode is switched to the multi-domain mode in order to enlarge the viewing angle) 28 (1997), 845), (3) a rod-shaped liquid crystalline molecule is substantially vertically oriented when no voltage is applied, whereas a mode that is deformed and oriented in the multi-domain when voltage is applied (n-ASM Liquid crystal cell (Preprints of Symposium on Japan Liquid Crystal Society, (1998), pages 58 to 59) of a mode) and (4) a liquid crystal cell of a SVRAIAI mode (presented in LC98).

(IPS mode liquid crystal display element)

When no voltage is applied, the rod-like liquid crystal molecules are substantially horizontally aligned in-plane, and this is characterized by switching by changing the alignment direction of the liquid crystal with or without voltage. Specifically, those described in Patent Publication No. 2004-365941, Patent Publication 2004-12731, Patent Publication 2004-215620, Patent Publication 2002-221726, Patent Publication 2002-55341, Patent Publication 2003-195333, and the like. Can be used.

(Other liquid crystal display element)

In the ECC mode and the ST mode, optical compensation can be achieved by the same approach as described above.

(C) Provision of antireflection layer (antireflection film)

The antireflection film is generally produced by forming a low refractive index layer provided as an antifouling layer and at least one layer (ie, a high refractive index layer or a medium refractive index layer) having a higher refractive index than the low refractive index layer on a transparent support.

A method of forming a multilayer film in which transparent thin films of inorganic compounds (metal oxides, etc.) having different refractive indices are laminated.Coloids are colloidally formed by chemical vapor deposition (CHD), physical vapor deposition (PCD), and sol-gel methods on metal compounds such as metal alkoxides. After forming a phase metal oxide particle film, the post-processing (ultraviolet irradiation of Unexamined-Japanese-Patent No. 9-157855, the plasma process of Unexamined-Japanese-Patent No. 2002-327310) is mentioned, and the method of forming a thin film is mentioned.

On the other hand, as a highly productive antireflection film, various antireflection films formed by laminating thin films of inorganic particles dispersed in a matrix have been proposed.

By forming fine unevenness on the uppermost layer of the antireflection film produced by the coating method as described above, an antireflection film having an antireflection layer imparting anti-glare property can be used.

Although it can apply | coat to the cellulose acylate film of this invention by said arbitrary methods, the coating method (coating type) is especially preferable.

(C-1) Layer composition of coated antireflection film

The antireflection film having a layer structure formed in the order of at least the medium refractive index layer, the high refractive index layer, and the low refractive index layer (outermost layer) on the support is designed to have a refractive index that satisfies the following relationship.

Refractive Index of High Refractive Index Layer> Refractive Index of Middle Refractive Index Layer> Refractive Index of Transparent Supporting> Refractive Index of Low Refractive Index Layer

A hard coat layer may be formed between the transparent support and the medium refractive index layer. The antireflection film may be composed of a medium refractive index hard coat layer, a high refractive index layer, and a low refractive index layer.

For example, Japanese Patent Laid-Open No. 8-122504, Japanese Patent Laid-Open No. 8-110401, Japanese Patent Laid-Open No. 10-300902, Japanese Patent Laid-Open No. 2002-243906, Japanese Patent Laid-Open No. 2000-111706, and the like. In addition, these layers may have other functions, for example, a low refractive index layer having antifouling properties, and a high refractive index layer having antistatic properties (e.g., Japanese Patent Laid-Open No. 10-206603, Japanese Patent Laid-Open No. 2002-243906, etc.). ), And the like.

It is preferable that it is 5% or less, and, as for the haze of an antireflection film, 3% or less is more preferable. The strength of the film is measured by a pencil hardness test according to JIS K5400, preferably H or more, more preferably 2H or more, and most preferably 3H or more.

(C-2) High refractive index layer and medium refractive index layer

The high refractive index of the antireflection film is a curable film containing inorganic particles ultrafine particles having a high refractive index and an matrix binder of at least 100 nm in average particle diameter.

The high refractive index inorganic compound fine particles may be an inorganic compound having a refractive index of 1.65 or more, and preferably a refractive index of 1.9 or more. Examples thereof include oxides such as Ti, Vn, Sb, Sn, Cr, Ce, Ta, La, or In, and complex oxides containing these metal atoms.

Such ultrafine particles are obtained by treating a particle surface with a surface treatment agent (for example, a silane coupling agent or the like: Japanese Patent Laid-Open No. 11-295503, Japanese Patent Laid-Open No. 11-153703, and Japanese Patent Laid-Open No. 2000-9908, or anion) Sex compound or organometallic coupling agent: Japanese Patent Laid-Open No. 2001-310432, etc.), forming a core shell structure in which high refractive index particles constitute the core (Japanese Patent Laid-Open No. 2001-166104, etc.), using a specific dispersant in combination. (For example, Japanese Patent Laid-Open No. 11-153703, US Patent 6,210,858B1, Japanese Patent Laid-Open No. 2002-2776069, etc.).

As a material which comprises a matrix, a conventionally well-known thermoplastic resin or curable resin film may be sufficient.

At least one composition selected from a composition containing a polyfunctional compound having at least two radical polymerizable groups and / or a cationic polymerizable group, an organometallic compound containing a hydrolyzable group and a subcondensate composition thereof is preferable. For example, the compound of Unexamined-Japanese-Patent No. 2000-47004, Unexamined-Japanese-Patent No. 2001-315242, Unexamined-Japanese-Patent No. 2001-31871, and Unexamined-Japanese-Patent No. 2001-296401 is mentioned.

The curable film prepared using the colloidal metal oxide obtained from the hydrolysis-condensation product of a metal alkoxide and a metal alkoxide composition is also preferable. Such membranes are described, for example, in Japanese Patent Application Laid-Open No. 2001-293818.

The refractive index of the high refractive index layer is generally 1.70 to 2.20, the thickness is preferably 5 nm to 10 m, and more preferably 10 nm to 1 m.

The refractive index of the medium refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. It is preferable that the refractive index of a medium refractive index layer is 1.50-1.70.

(C-3) Low refractive index layer

The low refractive index layer is laminated on the high refractive index layer. The refractive index of the low refractive index layer is 1.20 to 1.55. Preferably it is 1.30-1.50.

It is preferable to form this layer as an outermost layer which has scratch resistance and antifouling property. It is effective to provide sliding property to the surface as a means of greatly improving scratch resistance, and a method of forming a thin film layer by introducing a conventionally known silicon or fluorine can be applied.

The refractive index of the fluorine compound is preferably 1.35 to 1.50, more preferably 1.36 to 1.47. As such a fluorine compound, the compound containing 35-80 mass%, and a crosslinkable or polymeric functional group are preferable.

For example, Paragraph No. 0018-0026 in the specification of Unexamined-Japanese-Patent No. 9-222503, Paragraph No. 0019-0030 in the specification of 11-38202, Paragraph No. 0027-0028 in the specification of Unexamined-Japanese-Patent No. 2001-40284, And the compounds described in JP-A-2000-284102.

The silicone compound preferably has a polysiloxane structure, contains a curable functional group or a polymerizable functional group in the polymer chain, and forms a crosslinked structure in the film. For example, reactive silicone (eg, Silaplane (commercially available from Chisso Corporation) and both ends) Polysiloxane (such as Japanese Patent Application Laid-open No. Hei 11-258403, etc.) containing a silanol group.

The crosslinking or polymerization reaction of such a fluorine-containing polymer and / or polymer of siloxane containing a crosslinkable group or a polymerizable group is simultaneously or applied to the coating composition for forming the outermost layer containing the polymerization initiator and / or the sensitizer. It is preferable to carry out by light irradiation or heating afterwards.

Also preferred is a sol-gel cured film obtained by curing an organometallic compound such as a silane coupling agent and a silane coupling agent containing a specific fluorine-containing hydrocarbon group by a condensation reaction in the presence of a catalyst. For example, a silane compound containing a polyfluoro alkyl group or a partial-hydrolysis condensate thereof (Japanese Patent Publication No. 58-142958, Japanese Patent Publication No. 58-147483, Japanese Patent Publication No. 58-147484, Japanese Patent Japanese Patent Laid-Open No. 9-157582, Japanese Patent Laid-Open No. 11-106704), a silyl compound containing a poly (perfluoroalkyl ether) group as a long chain group (Japanese Patent Laid-Open No. 2000-117902, Japanese Patent Laid-Open No. 2001-48590) And the compounds described in JP-A-2002-53804.

The low refractive index layer has a low refractive index of 1 to 150 nm of primary particle average diameters such as fillers other than the above components (for example, silicon dioxide (silica) and fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)). Inorganic compounds, organic fine particles described in paragraphs [0020] to [0038] of Japanese Patent Laid-Open No. 11-3820), additives such as a silane coupling agent, a lubricant, and a surfactant.

When the low refractive index layer is located at the outermost layer, the low refractive index layer may be formed by a gas phase method (vacuum deposition method, sputtering method, ion plating method, plasma CVD method, or the like). Since it can manufacture at low cost, it is preferable to form a low refractive index layer by the apply | coating method. It is preferable that the film thickness of a low refractive index layer is 30-200 nm, It is more preferable that it is 50-150 nm, It is most preferable that it is 60-120 nm.

(C-4) Hard coat layer

The hard coat layer is formed on the surface of the transparent support to impart physical strength to the antireflection film. In particular, it is preferable to form a hard coat layer between the transparent support and the high refractive index layer.

It is preferable that a hard-coat layer is formed by carrying out the crosslinking reaction of a light and / or thermosetting compound, or a polymerization reaction.

As a curable functional group, a photopolymerizable functional group is preferable, and the organometallic compound containing a hydrolysable functional group is preferably an organic alkoxy silyl compound.

Specific examples of these compounds are the same as those listed in the case of the high refractive index layer. As a specific example of the composition which comprises a hard-coat layer, what was described, for example in Unexamined-Japanese-Patent No. 2002-144913, Unexamined-Japanese-Patent No. 2000-9908, and WO0 / 46617 is mentioned.

The high refractive index layer can be provided as a hard coat layer. The fine particles may be finely dispersed and included in the hard coat layer by using the method described in the part of such a high refractive index layer. The hard coat layer can be provided as an antiglare layer having an antiglare function (described later) by adding particles having an average particle diameter of 0.2 to 10 µm.

The film thickness of a hard coat layer can be designed suitably according to a use. It is preferable that the film thickness of a hard-coat layer is 0.2-10 micrometers, More preferably, it is 0.5-7 micrometers. The strength of the hard coat layer was measured by a pencil hardness test according to JIS K5400, preferably at least H, more preferably at least 2H, and most preferably at least 3H. In addition, after the taper test according to JISX5400, it is preferable that the amount of wear of the specimen is smaller.

(C-5) Front scattering layer

The forward scattering layer is formed in order to combine the film with a liquid crystal display element and to give an effect of improving the viewing angle when the viewing angle is inclined in the vertical, horizontal, left and right directions. It may have a hard coat function by dispersing fine particles having different refractive indices in the hard coat layer.

Such layers have specific forward scattering coefficients (Japanese Patent Laid-Open No. 11-38208), relative refractive indices of transparent resin and fine particles within a specific range (Japanese Patent Laid-Open No. 2000-199809), and specific haze values And 40% or more (Japanese Patent Laid-Open No. 2002-107512).

(C-6) Other layers

In addition to the above-mentioned layer, the anti-reflective layer may have a primer layer, an antistatic layer, a lower coating layer or a protective layer.

(C-7) Application method

The layer of the antireflection film is applied by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, a micro gravure coating method and an extrusion coating method (US Patent No. 2,681, 294). Can be formed.

(C-8) Antiglare function

The antireflection film may have an antiglare function for scattering external light. The antiglare function can be obtained by forming irregularities on the surface of the antireflection film. When the antireflection film has an antiglare function, the haze of the antireflection film is preferably 3 to 30%, more preferably 5 to 20%, and most preferably 7 to 20%.

As the method of forming the irregularities on the surface of the antireflection film, any method capable of forming and sufficiently maintaining such irregularities can be used. For example, a method of forming irregularities on the film surface by using fine particles in the low refractive index layer (for example, Japanese Patent Application Laid-Open No. 2000-271878), a layer formed under the low refractive index layer (high refractive index layer, medium refractive index layer or After adding a small amount (0.1-50 mass%) of comparatively large particle | grains (particle size 0.05-5 micrometers) to a hard-coat layer, and forming a surface asperity film | membrane, a method of forming a low refractive index layer by maintaining a surface shape on it (for example, Japanese Patent Laid-Open No. 2000-281410, Japanese Patent Laid-Open No. 2000-95893, Japanese Patent Laid-Open No. 2001-100004, and Japanese Patent Laid-Open No. 2001-281407, and the like, and the top layer (antifouling layer) are applied to the surface thereof. And the like (for example, embossing, Japanese Patent Laid-Open No. 63-278839, Japanese Patent Laid-Open No. 11-183710, and Japanese Patent Laid-Open No. 2000-275401). have.

It describes about the measuring method used by this invention below.

[1] Ｒｅ, ｔｔｈassay

The sample membrane was conditioned at a temperature of 5 ° C. and a humidity of 60% rh for at least 3 hours. Using an automatic birefringence meter (KOBRA-21ADH / PR, manufactured by Oji Scientific Instruments) at 25 ° C. and 60% rh, the wavelength from the direction perpendicular to the sample film surface and inclined ± 40 ° from the normal of the film surface. The delay value at 550 nm is measured.

The in-plane delay R e is calculated from the vertical direction, and the delay value R t e in the thickness direction is calculated from the measured value in the direction inclined at ± 40 ° from the vertical direction.

[2] R e, Rｔ

(1) MD direction sampling

The film was cut into 100-point, 1-cm squares at 0.5 m intervals in the length direction.

(2) TD sampling

50 points | pieces were cut | disconnected at equal intervals in the size of 1 cm square over the film forming width of a film | membrane.

(3) Ｒｅ, Ｒｔｈ, measurement

The sample membrane was conditioned at a temperature of 5 ° C. and a humidity of 60% rh for at least 3 hours. Using an automatic birefringence meter (KOBRA-21ADH / PR, manufactured by Oji Scientific Instruments) at 25 ° C. and 60% rh at a wavelength of 550 nm from the direction inclined ± 40 ° from the normal to the sample film surface and the normal of the film surface. The delay value is measured. The in-plane retardation (R) is calculated from the vertical direction, and the retardation value (R) is calculated in the thickness direction from the measured value in the direction inclined at ± 40 ° from the vertical direction.

The total average of the sampling points is referred to as R e and R t.

(4) Changes in JR and Ｒｔｈ

The difference between each maximum value and minimum value of these 100 points in the machine direction and 50 points in the lateral direction was divided by each average value and expressed as a percentage, which was referred to as R e and R p variation.

[3] destruction elongation by extension

Using heated tensilon, a product of Toyo Seiki Co., Ltd., preheated for 1 minute in an oven heated to Tg + 10 ° C of each sample, and then stretched until fracture at 100mm / mni The breaking elongation was measured.

[4] substitution degree of cellulose acylate

The acyl substitution degree of a cellulose acylate is CARC. It measured using 13C-NM by the method of 273 (1995) 83-91 (Tezuka et al.).

[5] DSC

It measured at the temperature rise rate of 10 degree-C / mI, using DC-50 made from Shimadzu Corporation, and calculated the amount of heat of the endothermic peak which appears immediately after Tg, and measured Tg simultaneously.

[6] haze

It measured using the turbidity meter NHD1-100P which is a product of Nippon Denshoku Industries Co., Ltd.

[7] yellow roads

Yellowing degree (XI) was measured along with (ZIS K71056.3) using the Z-II OPEL SSENNSOR.

The yellowness of the pellet was measured by the reflection method, and the membrane measured the tristimulus values, X, Y, and Z by the transmission method, and calculated the GI value by the following formula.

VII = {(1.28X-1.06Z) / Y} × 100

The VI value calculated by the said formula was divided by the thickness of the film | membrane, and it converted into per 1 mm, and compared.

[7] molecular weights

Membrane samples were dissolved in dichloromethane and measured using a PCC.

1 is a block diagram of a film production apparatus to which the present invention is applied.

2 is a schematic view showing the configuration of an extruder.

3A to 3E are tables illustrating embodiments of the present invention.

4 is a table for explaining a polarizing plate of an embodiment of the present invention.

Explanation of Symbols

10 production

11 extruder

12 die

14 Cooling Drum

16 cellulose acylate membrane (unstretched)

20 Longitudinal Drawing Process

22, 24 nip roll

26 cylinder

28 screw shaft

30 Horizontal stretching process

31 flights

32 single screw

34 supply port

36 outlet

40 windings

Supply unit of A extruder

Compression unit of B extruder

Measuring Unit of C Extruder

[Cellulose Acylate Resin]

Cellulose acylates having different acyl groups as shown in Table 1 of FIGS. 3A to 3E and different degrees of substitution were prepared. Specifically, sulfuric acid (7.7 parts by weight relative to 100 parts by weight of cellulose) was added as a catalyst, carboxylic acid serving as a raw material of the acyl substituent was added, and acylation was performed at 40 ° C.

At this time, the kind of acyl group and substitution degree were adjusted by adjusting the kind and amount of carboxylic acid. After acylation, aging was performed at 40 ° C. The polymerization degree of the cellulose acylate obtained in this way was determined by the following method, and it described in the table | surface of FIGS. 3A-3E.

(Polymerization measurement method)

About 0.2 g of completely dried cellulose acylate was precisely weighed and dissolved in 100 ml of a mixed solvent of methylene chloride: ethanol = 9: 1 (mass ratio). The number of fall seconds was measured at 25 degreeC with the Oswald viscometer, and the degree of polymerization was converted by the following formula | equation.

η rel = T / T0

[η] = (1nηrel) ／ C

Dp = [η] / mm

T ： The number of seconds to drop the measurement sample

T0: Falling seconds of the solvent only

C ： Concentration (g / l)

Mm: 6 × 10 ^-4

The Tg of these resin was measured by the following method, and it described in the table | surface of FIG. 3A-3E. Moreover, addition of the plasticizer showed the value measured after plasticizer addition.

(Tg measurement)

20 mg of the sample is put into a DC pan. This was heated to 30 ° C. to 250 ° C. at 10 ° C./min under nitrogen stream (1 st-run), and then cooled to −10 ° C./min to 30 ° C. Then, it heats up from 30 degreeC to 250 degreeC (2nd-run). The temperature at which the baseline starts to slope to the low temperature side in 2nd-run is referred to as the glass transition temperature (TG) and described in the tables of FIGS. 3A to 3E. In addition, 0.05 mass% of silicon dioxide fine particles (AEROSIL R972V) were added to all the samples.

[Melting agent film]

The said cellulose acylate resin was formed in the cylindrical pellet of diameter 3mm length 5mm. Here, plasticizers were selected and kneaded into pellets from the ones described below (Figs. 3A to 3E). These were dried with a vacuum dryer at 110 ° C, the water content was 0.1% or less, and then adjusted to a TG-10 ° C to the hopper. Committed. In the table of FIGS. 3A to 3E, TPP: triphenyl phosphate, GP: biphenyl diphenyl phosphate, DAO: bis (2-ethylhexyl) adipate, and PTP: 1,4-phenylene-tetraphenyl phosphate ester are shown. have.

Melting temperature was adjusted so that melt viscosity might be set to 1000 Pa · s, and it melt | dissolved using the single-screw extruder 11 set at 210 degreeC. The cellulose acylate film was formed by solidifying extrusion cooling in a sheet form on the cooling drum 14 set at Tg-5 ° C through the T-type die 12 set at the melting temperature. At this time, the electrostatic application method was used for each sample (a 10-kV wire was installed on the casting drum 14 at 10 cm from the point of melting landing). The fixed sheet was peeled off and wound up. Immediately before winding, both ends (each 3% of the full width) were trimmed, and thickness improvement process (knurling) was performed to achieve width 10mm and height 50 micrometers. Each sample was wound up at 30 m / min with a width of 1.5 m and a length of 3000 m.

[Extension]

The cellulose acylate film produced by the melt agent film was preheated with a preheat roll, and then stretched at the temperature and aspect ratio shown in the tables of FIGS. 3A to 3E. In addition, extending | stretching temperature showed "great Tg" by the temperature display of + and-, respectively, how many degrees higher or lower than the Tg of each resin of each Example and a comparative example was shown. Longitudinal stretching and lateral stretching were performed at the same temperature, and it showed "stretching temperature" in the table | surface.

In Examples 1-1 to 1-24 and Comparative Examples 1-1 and 1-2 shown in the tables of FIGS. 3A to 3E, elongated cellulose acyl removed using each of the cellulose acylate membranes prepared under the film forming conditions described in the table. The quality of the late film was evaluated. The items of quality evaluation include Re, its variation, Rth, its variation, haze, YI value, film thickness, and elongation at break.

<< Quality Evaluation of Stretched Cellulose Acylate Membrane >>

The values in the tables of FIGS. 3A-3E indicate the specific film forming conditions, stretching conditions, and acceptable quality values of the drawn acylate film.

Compression ratio of extruder: 2.5 ~ 4.5

Extruder L / D: 20 ~ 50

Extrusion temperature: 190 ~ 240 ℃

Preheating temperature during vertical stretching: Tg-40 ℃ ~ Tg + 60 ℃

Elongation ratio for vertical stretching: 1.01 to 3.0

Stretch ratio in horizontal stretching: 1.0 to 2.5

DSC endothermic peak value: 4.0 J / g or less

Re: 0 ~ 500nm

Re's coefficient of variation: 5% or less

Rth: 30 ~ 500nm

Rth variation coefficient: 5% or less

Haze value: 2% or less

YI value: 10 or less

Film thickness: 30 to 300 µm

Elongation at break during stretching: 50% or more (1.5 times the value before stretching)

3A to 3E, when the cellulose acylate film (unstretched) was set to 190 ° C (lower limit) and 220 ° C to 240 ° C (upper limit) in Examples 1-1 to 1-3, the extrusion temperature was It is within the scope defined in the present invention. On the other hand, in Comparative Examples 1-1 and 1-2, the extrusion temperature is set to 185 ° C (less than the lower limit of the present invention) and 245 ° C (above the upper limit of the present invention), and is outside the defined range of the present invention.

When the stretched cellulose acylate membrane is prepared using the unstretched cellulose acylate membrane prepared under the extrusion temperature conditions of the above examples and comparative examples, the breaking elongation at the time of stretching is 70% in Examples 1-1 to 1-3. It is 1.7 times of value)-180% (2.8 times of the value before extending | stretching), and shows the outstanding stretchability. The improvement in ductility results in an index of the amount of fine crystals present in the cellulose acylate film without the presence of fine crystals in the formed cellulose acylate film whose DSC endothermic peak value is 4 J / g or less and the haze is demonstrated by 1.5% or less. Indicates. Therefore, the stretched cellulose acylate membrane shows good results with Re of 40 to 50 (variation coefficient of 2 to 4%) and Rth of 240 to 260 (variation coefficient of 2 to 4%). In addition, since the extrusion temperature is 240 ° C. or lower, good results with YI values of 3 to 6 are obtained, which means that yellowness is substantially not generated.

On the other hand, in Comparative Example 1-1, the breaking elongation at the time of stretching was 47% (1.47 times the value before stretching) that was less than 50% of the passing point (1.5 times the value before stretching), and was broken in the stretching step and stretched the cellulose. Acylate membranes cannot be prepared. It is consistent with the fact that the index of the microcrystalline amount present in the cellulose acylate film, that is, the DSC endothermic peak value is 5.4 J / g, which is larger than 4 J / g, and the haze value is 2.3%, is greater than 2%. Further, in Comparative Example 1-2, since the melt extrusion temperature was 245 ° C and higher than 240 ° C, a result of excellent fracture elongation at 220% (2.2 times the value before stretching) was obtained, but the YI value was 11 , The passing point is 10, and the cellulose acylate film becomes dark yellow.

Examples 1-4 to 1-8 were changed to the preheating temperature at the time of longitudinal stretching in the range of Tg-40 ° C to Tg + 60 ° C, and were carried out at a constant extrusion temperature of 230 ° C. The stretched cellulose acylate film obtained by stretching the prepared cellulose acylate film has sufficient levels of coefficients of variation of Re, Re and Rth, coefficients of variation of Rth, haze, YI value, film thickness and breaking elongation at the time of stretching.

Examples 1-9 to 1-13 were changed to a screw compression ratio of 2.5 to 4.5 within the range defined in the present invention, and were carried out at a constant extrusion temperature of 230 deg. The stretched cellulose acylate film obtained by stretching the prepared cellulose acylate film has an acceptable quality level of variation coefficients of Re, Re and Rth, variation coefficient of Rth, haze, YI value, film thickness and elongation at break.

Examples 1-14 to 1-18 were carried out at a constant screw compression ratio 3.5 and a constant L / D 50, which were the upper limits defined in the present invention, varying the extrusion temperature within the range defined in the present invention to 190 to 240 ° C. The stretched cellulose acylate film obtained by stretching the prepared cellulose acylate film has sufficient quality levels of the coefficient of variation of Re, Re, and Rth, the coefficient of variation of Rth, haze, YI value, film thickness, and breaking elongation at the time of stretching.

Examples 1-19-1-24 were performed by changing substitution degree and the cellulose acylate molecular weight, and changing the holding transition temperature of a cellulose acylate resin in the range of 120 degreeC-170 degreeC. The stretched cellulose acylate film obtained by stretching the prepared cellulose acylate film has an acceptable quality level of variation coefficients of Re, Re and Rth, variation coefficient of Rth, haze, YI value, film thickness and elongation at break.

Tables 3a to 3e show only the case where the screw compression ratio satisfies 2.5 to 4.5. When the screw compression ratio was 4.5 or more, the molecules were destroyed and the molecular weight was reduced, so that the mechanical strength of the prepared cellulose acylate membrane was significantly reduced. The following stretching process was not performed. When the screw compression ratio was less than 2.5, melting was insufficient, unmelted particles were generated, or bubbles were mixed. The following stretching process was not performed.

The tables in Figs. 3A to 3E show only the case where L / D satisfies 20 to 50. When the L / D was less than 20, unmelted particles were generated, and the following stretching step was not performed. When the L / D exceeds 50, the molecules are destroyed and the molecular weight is reduced, so that the mechanical strength of the prepared cellulose acylate film is significantly reduced. The following stretching step is not performed.

[Production of Polarizing Plate]

(1) production of polarizing plates

The unstretched film was prepared under the film forming conditions of Example 1 of Table 1 shown in FIGS. 3A to 3E, and the material of the film (degree of substitution, degree of polymerization, plasticizer) was changed as described in Table 2 shown in FIG. Was prepared.

(1-1) Saponification of Cellulose Acylate Film

The unstretched cellulose acylate film was sensitized by the following liquid immersion. What was subjected to the sensitization by the following application showed quite the same result.

(i) influencing by application

20 parts by weight of water was added to 80 parts by weight of iso-propanol, and pH was dissolved so as to be 2.5N. The obtained mixture was adjusted to 60 degreeC and used as a saponification liquid. This solution was apply | coated at 10 g / m <^2> on the cellulose acylate film | membrane of 60 degreeC, and it was sensitized for 1 minute. Next, using a spray, 50 degreeC warm water was sprayed at 10 l / m <^2> * min for 1 minute, and it wash | cleaned.

(b) Immersion Reduction

A 2.5N NAOH aqueous solution was used as a saponification liquid. This solution was adjusted to 60 degreeC, and the cellulose acylate membrane was immersed for 2 minutes. Subsequently, it was immersed in 0.1 N sulfuric acid solution for 30 seconds, and then passed through a water bath.

(1-2) Manufacturing of Polarizing Plate

According to Example 1 of Unexamined-Japanese-Patent No. 2001-141926, the circumferential speed difference was provided between two nip rolls, it extended | stretched in the longitudinal direction, and produced the polarizing layer of 20 micrometers in thickness.

(1-3) adhesion

The polarizing layer thus obtained was subjected to the above-described unstretched and stretched cellulose acylate film and FUJITAC (unstretched triacetate film) subjected to the sensitized treatment to form a film forming flow direction (length direction) of the cellulose acylate film in the following combination. It laminated | stacked using 3% aqueous solution of PAA (PAA-117H by Kurary Co., Ltd.) as an adhesive agent in the extending direction of a polarizing film.

Polarizing plate A: Unstretched cellulose acylate film / polarizing layer / FUJITAC

Polarizing plate B: Unstretched cellulose acylate film / polarizing layer / unstretched cellulose acylate film

(1-4) Color change of polarizer

The color change degree of the polarizing plate thus obtained was evaluated in the range of 1 to 10 (the larger the number, the larger the color change). All of the polarizer plates produced according to the present invention showed excellent results.

(1-5) Evaluation of humidity curl

The humidity curl of the obtained polarizing plate was measured by the said method. The application of the present invention showed excellent characteristics (low humidity curl) even after the polarizing plate was formed.

The polarizing plate which laminated | stacked the polarizing axis and the cellulose acylate film | membrane longitudinal direction or right angle 45 degree | times was laminated | stacked, and performed the same evaluation. Both show the same result as above in the case of parallel lamination.

(2) Manufacture of compensation films and liquid crystal display elements

After removing the polarizing plate attached to the viewer side of the 22-inch liquid crystal display element by using a VA type liquid crystal (manufactured by Sharp Corporation), and using the delayed polarizing plate A or B instead, the polarizing plate was removed and the adhesive was removed. The polarizing plate is adhere | attached on the viewer side using this, and a cellulose acylate film exists on the side of a liquid crystal cell. The plate was placed on the viewer's field of view so that the transition axis of the polarizing plate and the backlight axis were perpendicular to each other, thereby completing the liquid crystal display element.

Since the polarizing plate according to the present invention has little humidity curl and is easy to bond, hardly any misalignment was found when bonding.

In addition, the cellulose acylate film of the present invention was used in place of the cellulose acylate film of Example 1 of JP-A-11-316378 to which a liquid crystal layer was applied, thereby obtaining an excellent compensation film having almost no humidity curl.

When the cellulose acylate film of the present invention is used in place of the cellulose acetate film of Example 1 of Japanese Patent Application Laid-open No. Hei 7-333433 in which a liquid crystal layer is applied to produce a compensation filter film, an excellent compensation film having almost no humidity curl is produced. did.

The polarizing plate or delayed polarization of the present invention is an optically anisotropic layer containing the liquid crystal display device described in Example 1 of Japanese Patent Application Laid-open No. Hei 10-48420, and the optically anisotropic layer containing the tistronic liquid crystal molecule of Example 1 , An alignment film coated with the polyvinyl alcohol of FIGS. 2 to 9 of Japanese Patent Application Laid-Open No. 2000-154261, a 20-inch VA type liquid crystal display device, and a 20-inch OCB described in FIGS. 10 to 15 of Japanese Patent Publication No. 2000-154261. It applies to the type | mold liquid crystal display element and the IPS type liquid crystal display element of FIG. 11 of Unexamined-Japanese-Patent No. 2004-12731. Thus, an excellent liquid crystal display device having no humidity curl was produced.

(3) Preparation of low reflection film

Using the cellulose acylate membrane of the present invention, it was prepared according to Example 47 of "Kokai Giho of Japan Institute of Invention & Innovation" (Publication 2001-1745). The humidity curl measurement was performed on the obtained membrane. Application of the present invention showed good results when a polarizing plate was produced. In addition, the low reflection film of the present invention is the outermost layer of the liquid crystal display device described in Example 1 of Japanese Patent Application Laid-open No. Hei 10-48420, and the 20-inch VA type liquid crystal display device described in FIGS. And the 20-inch OCB type liquid crystal display device described in FIGS. 10 to 15 of Japanese Patent Application Laid-Open No. 2000-154261 and the IPS type liquid crystal display device described in Figure 11 of Japanese Patent Application Laid-Open No. 2004-12731 to evaluate the device. Carried out. Thus, an excellent liquid crystal display element is obtained.

Claims (15)

In the method for producing a cellulose acylate membrane by the melt film forming method, an extrusion temperature of 190 ° C to 240 ° C for a cellulose acylate resin using an extruder having a screw compression ratio of 2.5 to 4.5 and an L / D of 20 to 50. Extruding the sheet through a die into a sheet shape over the cooling support; And Cold fixing the sheet. A cellulose acylate membrane, characterized in that the elongation at break when the cellulose acylate membrane is uniaxially stretched at a glass transition temperature of Tg + 10 ° C. is 50% or more. The film has an endothermic peak value of 4.0, wherein haze is 2.0% or less, yellowing degree is 10 or less, and a peak appears in a region having a glass transition temperature Tg or more in a differential scanning calorimetry (DSC) measurement. The cellulose acylate film | membrane characterized by below J / g. The acylate group according to claim 2 or 3, wherein A is the sum of the substitution degree of the acetyl group and the B substitution degree of the propionyl group, the butyryl group, the pentanoyl group, and the hexanoyl group. Cellulose acylate membrane, characterized in that to satisfy. 2.5 ≦ A + B <3.0, and 1.25≤B <3.0, The cellulose acylate membrane according to any one of claims 2 to 4, wherein the membrane has a molecular weight of 20,000 to 100,000. A method for producing a stretched cellulose acylate membrane, comprising stretching the unstretched cellulose acylate membrane produced by the method according to claim 1 in at least one to 2.5 times in at least one of the longitudinal and transverse directions of the membrane. The stretched cellulose acylate membrane obtained by extending | stretching the unstretched cellulose acylate membrane in any one of Claims 2-5 by 1 times-2.5 times in at least one direction of the longitudinal direction and the lateral direction of the said membrane. The stretched cellulose acylate film according to claim 7, wherein the film has a thickness of 30 to 300 µm, an in-plane retardation of 0 nm to 500 nm, and a thickness direction retardation of 30 nm to 500 nm. 9. The stretched cellulose acylate film according to claim 8, wherein the variation of Rhe and Rt is 5% or less in both the width direction and the length direction. At least one layer of the unstretched cellulose acylate film as described in any one of Claims 1-5 is contained, The polarizing plate characterized by the above-mentioned. The unstretched cellulose acylate film of any one of Claims 1-5 is contained as a support body of a compensation film, The compensation film for liquid crystal display panels characterized by the above-mentioned. The anti-reflective film containing the unstretched cellulose acylate film in any one of Claims 1-5 as a support body of an anti-reflective film. At least one layer of the stretched cellulose acylate film according to any one of claims 7 to 9 is laminated. The compensated film of a liquid crystal display panel containing the stretched cellulose acylate film in any one of Claims 7-9 as said compensation film. An antireflection film containing the stretched cellulose acylate film according to any one of claims 7 to 9 as the antireflection film.

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