WO2005100458A1

WO2005100458A1 - Cellulose ester film

Info

Publication number: WO2005100458A1
Application number: PCT/JP2005/006765
Authority: WO
Inventors: Masahiro Shibuya
Original assignee: Konica Minolta Opto, Inc.
Priority date: 2004-04-16
Filing date: 2005-04-06
Publication date: 2005-10-27
Also published as: KR20060133010A; CN1942511A; TW200617070A; TWI375696B; JP2005306900A

Abstract

A cellulose ester film containing a matting agent, characterized in that the formula: 0.8 ≤ μA/μB ≤ 1.3, wherein μB represents a coefficient of dynamic friction at a face contact load of 300 g (apparent area 63 X 63 mm2), and μA represents a coefficient of dynamic friction at a face contact load of 1000 g (apparent area 63 X 63 mm2), is satisfied.

Description

Specification

Senole mouth beauty salon / Refinolem technical field

The present invention relates to a cellulose ester film which is useful as a protective film for a polarizing plate of a liquid crystal display (LCD), and in particular, can improve the winding quality with a rolled product of 5000 m or more. .

Background art

[0002] As a protective film for a polarizing plate of a liquid crystal display (LCD), a cellulose ester film is used. In a conventional method for producing a cellulose ester film, for example, a cellulose ester solution (hereinafter also referred to as a “dope”) is transferred to an endless endless support (stainless steel) having a mirror-finished surface by a solution casting method. A casting die force is also cast on a belt (made of a belt or a drum), and the dope film (hereinafter, also referred to as a web) is peeled off by a peeling roll (peeling point). The cellulose ester film was dried to obtain a cellulose ester film, and then wound up by a winder to produce a cellulose ester film. As a protective film for a polarizing plate of an LCD, among cellulose ester films, a cellulose triacetate (TAC) film is mainly used.

[0003] Conventionally, in the production of cellulose ester films, production of 2,000 m rolls of film has been common, but in recent years, due to growing demand for cellulose ester films, film production has been increasing to 2,500 m to 4,000 m. It is anticipated that film production will exceed 5000 m rolls in the future due to high film production!

[0004] However, when the winding diameter of the cellulose ester film is increased as described above, the force applied to the wound film is increased, and the appearance of the wound is deteriorated, the slipperiness between the films is deteriorated, that is, the winding is reduced. There was a phenomenon that the quality deteriorated.

[0005] Prior patent documents relating to the improvement of the surface physical properties of a cellulose ester film used for a protective film for a polarizing plate, which is considered to relate to the winding quality of these films, include the following.

Patent Document 1: Japanese Patent Application Laid-Open No. 5-53244 The present applicant has previously made it possible to perform thin film The invention of a silver halide photographic support having excellent film properties without devitrification or sticking between films has been proposed.

[0006] The invention described in Patent Document 1 is a silver halide photographic support having an undercoat layer containing a matting agent on both sides of the support, and the support has a thickness of 50 m or more. : LO 0 / zm, wherein one subbing layer and the other sublayer each contained a matting agent having a different average particle size.

Patent Document 2: Japanese Patent Application Laid-Open No. 2001-51378 The applicant of the present invention has proposed a method in which blocking during winding in a roll shape and blocking in the process of heat treatment in a roll shape are not caused. The present invention provides a support for a silver photographic light-sensitive material, and proposes an invention of a silver halide photographic light-sensitive material which does not cause stains or coating defects in a process of coating and drying an emulsion layer and the like.

[0007] The invention described in Patent Document 2 relates to a support for a silver halide photographic material having at least one undercoat layer on one side and a back layer on the other side. The layer has a matting agent having an average primary particle diameter of 0.01 to 1.6 m, and the height of the matting agent protruding from the surface of the undercoat layer is 0.002 m or more. The size of the matting agent was specified.

Patent Literature 3: Japanese Patent Application Laid-Open No. 2001-163994 The present applicant has previously provided an antistatic layer on a resin film, and used it as a polarizing plate protective film. There is a problem that the antistatic layer is destroyed in the dangling process and the curl becomes large due to the influence of the coating solvent on the base material, and the additive is deposited during the production and contaminates the process or deposits on the film. The invention of a resin film and a method for producing the same, which have improved adhesive properties to a polarizer that does not block the back surface of the film and has high productivity, which has improved problems such as the problem of blemishes.

[0008] The invention described in Patent Document 3 is characterized in that the concentration of the antistatic agent on at least one surface side is different from the average concentration of the antistatic agent in the entire resin film. 4: Japanese Patent Application Laid-Open No. 2002-194106 The present applicant has proposed that the film forming process is not performed even when the polarizing plate protective film is thinned with the thin film of the liquid crystal display element. In addition, the present inventors have proposed an invention of a cellulose ester film and a method for producing the same, which are excellent in handleability in a polarizing plate production process.

[0009] The invention described in the patent document 4 is the cellulose ester particles in the film, was characterized in 0.04 to 0.3 mass ^_0/0 to contain. Further, it was stipulated that the film contains a matting agent fine particle having an average particle size of 1.0 to: LO.O / zm.

Patent Document 5: Japanese Patent Application Laid-Open No. 2002-265670 SUMMARY OF THE INVENTION The present applicant has previously solved the problems in the film forming step that occurs when a polarizing plate protective film is thinned and the polarizing plate making step. The invention of a cellulose ester film having excellent handling and properties and a method for producing the same has been proposed.

[0010] The invention described in Patent Document 5 relates to a cellulose ester film containing fine particles in a film, wherein the average primary particle size of the fine particles is 5 to 30 nm, and the average long axis particle size of the fine particles in the film is When the diameter was A (nm) and the added mass ratio of the fine particles to the cellulose ester in the film was B (%), the AXB was characterized by being 15 to 120. Further, the average particle size force of the fine particles in the cellulose ester film was specified to be 100 to 20 OO nm.

Patent Document 6: Japanese Patent Application Laid-Open No. 2002-317059 The invention described in Patent Document 6 is intended to improve the transportability and scratch resistance without impairing the transparency of the cell-port-assilate film, and to improve the cellulose resistance. In the cell mouth film formed by casting a solution in which the acylate is dissolved in a solvent, the content of the matting agent in the cellulose acylate film is set to 0.03 to 0.15% by weight. It was characterized by having made it. Further, it specified that the matting agent was silicon dioxide having an average particle size of 0.5 to: Lm.

Patent Document 7: Japanese Patent Application Laid-Open No. 2003-96208 The present applicant has previously proposed an invention of a cellulose ester film which does not cause wrinkling or breaking even when the film thickness is small.

[0011] The invention described in Patent Document 7 discloses that a cellulose ester film having a thickness of 60 µm or less has a coefficient of friction between film contact surfaces at a temperature of 23 ° C and a humidity of 55% of a, When b is the same coefficient at% and c is the same coefficient at temperature 23 ° C and humidity 85%, 1.0 ≤ b / a ≤ 1.5 and 1.0 ≤ c / a ≤ 5. 0, preferably 1.0 ≦ b / a ≦ l.5, and 1.0 ≦ c / a ≦ 2.0. In addition, cellulose ester fibers The average particle diameter of the fine particles in the lum and the distance between the particles were specified.

Disclosure of the invention

Problems to be solved by the invention

[0012] However, the conventional inventions described in Patent Documents 1 to 3 above all have a coating layer on a film, and are inventions relating to physical properties in the coating layer. The physical properties have been improved.

[0013] Further, all of the conventional inventions described in Patent Documents 4 to 7 have a problem that the effect of force improvement, which relates to the improvement of surface physical properties of the cellulose ester film itself, is insufficient. there were.

[0014] An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a cellulose ester film used as a protective film of a liquid crystal display element, that is, a polarizing plate, for example, to increase the winding diameter by 500 Om or more. An object of the present invention is to provide a cellulose ester film capable of suppressing deterioration of winding quality even with a wound product having a large load.

Means for solving the problem

[0015] The present inventor has conducted intensive studies in view of the above points, and as a result, the friction coefficient as an index of the slipperiness of the cellulose ester film is, in principle, the frictional resistance Z force under the surface contact load. Therefore, it should not depend on the load. In other words, even if the load changes, the friction coefficient does not change. However, in general, the friction coefficient may change with the change in load depending on the state of the friction surface, the state of contact, etc., but the absence of this change indicates a preferable surface state. . The present inventor has found that the smaller the change in the coefficient of friction is, the more preferable the form is, even if the load changes, and has accomplished the present invention. In particular, even when the load on the rolled film becomes excessive, for example, when the roll diameter of the film is increased, the deterioration of the winding quality of the cellulose ester film can be suppressed by keeping the friction coefficient unchanged. They have found and completed the present invention.

In order to achieve the above object, the invention of a cellulose ester film according to item 1 of the present invention relates to a cellulose ester film containing a matting agent, and has a surface contact load of 300 g (visual area 63 × 63 mm ² ), And the dynamic friction coefficient at the surface contact load lOOOOg (apparent area 63 X 63 mm ² ) is / z A, 0.8 ≤ ^ Α / ^ Β ≤ 1.3.

The invention described in Item 2 of the present invention is the cellulose ester film according to Item 1, wherein the arithmetic average roughness of the film is Ra, the ten-point average roughness is Rz, and the average distance between local peaks is : Sm force Each is within the following range.

[0018] 9. Onm≤Ra≤l l. Onm

150nm≤Rz≤250nm

10nm≤Sm≤300nm

The invention described in Item 3 of the present invention is the cellulose ester film described in Item 1 or 2, wherein the matting agent fine particles in the film have an average particle diameter of 100 to 500 nm, and the matting agent fine particles are used. The distance is 0.3 to 3 μm.

[0019] The invention described in Item 4 of the present invention is the cellulose ester film described in Item 1 or 2, wherein the average particle diameter of the matting agent fine particles in the film is 500 to 1000 nm, It is characterized in that the distance between the fine particles of the agent is 1 to 5 μm.

[0020] The invention described in Item 5 of the present invention is the cellulose ester film described in any one of Items 1 to 4, further comprising a compound represented by the general formula [I]:

[0021] [Formula 3]

B O

A-O-P-O-C… [I]

II

o

(Wherein, A, B and C represent a phenyl group or a biphenyl group, and at least two of A, B and C are biphenyl groups) Features that!

The invention according to Item 6 of the present invention is the cellulose ester film according to any one of Items 1 to 4, further comprising a compound represented by the general formula [I]:

[0024] [Formula 4] BO

A-O-P-O-C ■■■ [I]

II

o

Wherein, in the formula, A, B and C represent a phenyl group or a biphenyl group, and a compound in which at least two of A, B and C are a biphenyl group; Where A,

B and C represent a phenyl group or a biphenyl group, and at least two of A, B and C contain a compound which is a phenyl group.

[0026] The invention according to Item 7 of the present invention is the cellulose ester film according to any one of Items 1 to 4, further comprising an aliphatic polyhydric alcohol and one or more monocarboxylic acids. A content of 4.5 to 12.5% by weight of the cellulose ester film with respect to the cellulose ester film.

[0027] The invention described in Item 8 of the present invention is the cellulose ester film described in Item 7,

Monocarboxylic acid force A compound having an aromatic ring or a cycloalkyl ring in the molecule.

[0028] The invention according to Item 9 of the present invention is the cellulose ester film according to Item 7,

And aliphatic polyhydric alcohol having a hydration of 2 to 20.

[0029] The invention described in Item 10 of the present invention is the cellulose ester film described in Item 7, characterized in that the cellulose ester film has an aliphatic polyhydric alcohol power of 2 to 3 valences.

[0030] The invention according to Item 11 of the present invention is the cellulose ester film according to Item 7, wherein the aliphatic polyhydric alcohol has 4 or more carbon atoms.

The invention's effect

As described above, the invention of the cellulose ester film according to item 1 of the present invention is a cellulose ester film containing a matting agent, and has a dynamic friction coefficient at a surface contact load of 300 g (apparent area 63 × 63 mm ² ). B, when the dynamic friction coefficient at the surface contact load lOOOOg (visual area 63 X 63mm ² ) is A, 0.8≤ ^ Α / ^ Β≤1.3.According to the invention described in Item 1, a cellulose ester film used as a protective film of a liquid crystal display element, that is, a polarizing plate, For example, even with a wound product having a large load such as an increase in the diameter of a roll of 5000 m or more, it is possible to suppress the deterioration of the winding quality.

[0032] Further, the invention according to Item 2 of the present invention is the cellulose ester film according to Item 1, as described above, wherein the arithmetic average roughness of the film is Ra, the ten-point average roughness is Rz, Average distance between local peaks: Sm is within the following range.

[0033] 9. Onm≤Ra≤l l. Onm

150nm≤Rz≤250nm

10nm≤Sm≤300nm

According to the invention described in Item 2, by setting the surface condition of the film to the specific range, the coefficient of friction at the contact surface when the film comes into contact can be controlled to the specific range, Even if the load changes, the change in the coefficient of friction can be controlled to a specific range, and the film slip property relating to the winding quality can be maintained in a good state.For example, the winding diameter of the cellulose ester film can be increased. As a result, even if the force applied to the wound film increases, it is possible to prevent the deterioration of the appearance of the wound film and the deterioration of the slipperiness between the films, that is, the deterioration of the winding quality.

[0034] As described above, the invention according to Item 3 of the present invention is the cellulose ester film according to Item 1 or 2, wherein the matting agent fine particles in the film have an average particle diameter of 100 to 500 nm. In this case, the distance between the matting agent fine particles is 0.3 to 3 m.

Here, in order to set the kinetic friction coefficient of the wound cellulose ester film within a specific range, fine particles having a specific particle diameter are present at a specific interparticle distance. That is, since the fine particles are defined by the content and the content ratio inside the film, the degree of the presence of the fine particles, that is, the distance between the particles is defined.

[0036] According to the cellulose ester film according to item 3, by setting the surface condition of the film to a specific range, the coefficient of friction on the contact surface when the film comes into contact can be controlled to a specific range, and the contact load can be controlled. The change of the coefficient of friction can be controlled to a specific range even if the film changes, and the winding diameter of the cellulose ester film increases, and Even if the pressing force increases, it is possible to prevent the deterioration of the appearance of the film winding and the deterioration of the sliding property between the films, that is, the deterioration of the winding quality.

[0037] As described above, the invention according to Item 4 of the present invention is the cellulose ester film according to Item 1 or 2, wherein the matting agent fine particles in the film have an average particle diameter of 500 to 100 Onm. The matting agent fine particles have a distance between the particles of 1 to 5 m.According to the invention described in Item 4, similarly, by setting the surface state of the film to a specific range, In addition, the coefficient of friction at the contact surface when the film comes into contact can be controlled to a specific range, and even when the contact load changes, the change in the coefficient of friction can be controlled to a specific range. Even if the winding diameter increases and the force acting on the wound film increases, it is possible to prevent the deterioration of the appearance of the wound film and the deterioration of the slipperiness between the films, that is, the deterioration of the wound quality.

Next, a specific plasticizer is used to set the kinetic friction coefficient of the wound cellulose ester film within a specific range. The use of specific plasticizers reduces moisture absorption and permeability and improves film moisture resistance during humidity changes, which is closely linked to a reduction in friction coefficient and, consequently, an improvement in slipperiness.

That is, the invention described in Item 5 of the present invention is the cellulose ester film according to any one of Items 1 to 4, as described above, and further comprises the general formula [I]

[0040] [Formula 5]

B O

A-O-P-O-C… [I]

II

o

[0042] According to the invention described in Item 5, by setting the surface state of the film to a specific range, the coefficient of friction at the contact surface when the film comes into contact can be controlled to a specific range. Therefore, even if the contact load changes, the change in the friction coefficient can be controlled within a specific range, and the kinetic friction coefficient of the wound cellulose ester film can be set within the specific range. However, even if the winding diameter of the cellulose ester film is increased and the force applied to the wound film is increased, it is possible to prevent the deterioration of the film appearance and the slipperiness between the films, that is, the deterioration of the winding quality. It works. In particular, tris-biphenyl phosphate (TBP) has an effect of improving the hydrophobicity of the film and, as a result, improving the slipperiness.

As described above, the invention according to Item 6 of the present invention is the cellulose ester film according to any one of Items 1 to 4, wherein the cellulose ester film has the general formula [I]

[0044] [Formula 6]

B O

A-O-P-O-C… [I]

II

o

Wherein, in the formula, A, B and C represent a phenyl group or a biphenyl group, and a compound in which at least two of A, B and C are a biphenyl group; In the formula, A, B and C represent a phenyl group or a biphenyl group, and at least two of A, B and C contain a compound which is a phenyl group.

According to the invention described in Item 6, by setting the surface condition of the film to a specific range, the coefficient of friction on the contact surface when the film comes into contact can be controlled to a specific range. Even if the load changes, the change in the coefficient of friction can be controlled to a specific range, and even if the winding diameter of the cellulose ester film increases and the force applied to the winding film increases, the appearance of the wound film deteriorates. In addition, it is possible to prevent the deterioration of the slipperiness between the films, that is, the deterioration of the winding quality.

[0047] The invention described in Item 7 of the present invention is the cellulose ester film described in any one of Items 1 to 4, as described above, further comprising an aliphatic polyhydric alcohol and 1 Compounds consisting of polyhydric alcohol esters with at least one monocarboxylic acid According to the invention described in Item 7, the change in the coefficient of friction is controlled to a specific range even when the contact load changes, according to the invention described in Item 7. Therefore, it is possible to prevent deterioration of the appearance of the film winding and deterioration of the slipperiness between the films, that is, deterioration of the winding quality.

[0048] The invention described in Item 8 of the present invention is the cellulose ester film described in Item 7, as described above, wherein the monocarboxylic acid molecule has an aromatic ring or a cycloalkyl ring in the molecule. According to the invention described in Item 8, the change in the coefficient of friction can be controlled to a specific range even when the contact load changes, so that the appearance of the film winding deteriorates. In addition, it is possible to prevent the deterioration of the slipperiness between the films, that is, the deterioration of the winding quality.

[0049] The invention described in Item 9 of the present invention is, as described above, the cellulose ester film described in Item 7, characterized in that it has an aliphatic polyhydric alcohol power of 2 to 20. According to the invention described in Item 9, the change in the coefficient of friction can be controlled to a specific range even when the contact load changes, so that the deterioration of the film winding appearance and the slip property between the films can be achieved. This has the effect of preventing deterioration, that is, deterioration of winding quality.

[0050] The invention described in Item 10 of the present invention is characterized in that, as described above, the cellulose ester film described in Item 7, which has an aliphatic polyhydric alcohol power of 2 to 3 valences. According to the invention described in Item 10, even if the contact load changes, the change in the coefficient of friction can be controlled within a specific range, so that the deterioration of the film winding appearance and the slipperiness of the films can be prevented. This has the effect of preventing deterioration, that is, deterioration of winding quality.

As described above, the invention according to Item 11 of the present invention relates to the cellulose ester film according to Item 7, wherein the aliphatic polyhydric alcohol has 4 or more carbon atoms. According to the invention described in Item 11, the change in the coefficient of friction can be controlled to a specific range even when the contact load changes, so that the deterioration of the film winding appearance and the film This has the effect of preventing deterioration of the slipperiness of the roll, that is, deterioration of the winding quality.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail. is not.

The cellulose ester film according to the present invention is a cellulose ester film containing a matting agent, and has a dynamic friction coefficient at a surface contact load of 300 g (visual area 63 X 63 mm ² ) of / z B and a surface contact load of lOOOOg ( Let μ を be the kinetic friction coefficient at the apparent area 63 X 63 mm ² ).

0.8 ≤ ^ ^ / ^ Β ≤ 1.3.

[0054] As described above, since the friction coefficient as an index of the slipperiness of the cellulose ester film is determined in principle by the frictional resistance with the surface contact load divided by the load, it must be independent of the load. In other words, even if the load changes, the friction coefficient does not change. However, in general, the friction coefficient may change with a change in load depending on the state of the friction surface, the state of contact, etc., but a surface state where no change is preferable is indicated. . The present inventor has found that the smaller the change in the coefficient of friction is, the more preferable the form is, even if the load is changed, and has accomplished the present invention. In particular, even when the load on the rolled film is excessive, such as when the roll diameter of the film is increased, the deterioration of the winding quality of the cellulose ester film can be suppressed by keeping the friction coefficient unchanged.

The cellulose ester film according to the present invention has a dynamic friction coefficient B at a surface contact load of 300 g (visual area 4 × 63 × 63 mm ² ) and a dynamic friction coefficient at a surface contact load lOOOOg (visual area 63 × 63 mm ² ). When A

0.8≤ ^ Α / ^ Β≤1.3.

Here, if ix / μΒ is less than 0.8, the coefficient of kinetic friction at a low contact load increases, and film slippage on a rolled film having a small rolled diameter becomes difficult to occur. This is not preferable because it easily occurs. On the other hand, if ίίμΑΖμ exceeds 1.3, the dynamic friction coefficient under a high contact load increases, and the appearance of a late wound film having a large winding diameter tends to deteriorate, which is not preferable. As a result, if μ / μΒ is less than 0.8, the winding stability of the rolled film decreases, and the appearance tends to deteriorate, which is not preferable. Also, if AZ / i exceeds 1.3, the winding stability of the wound film is reduced, and the appearance tends to deteriorate, which is not preferable.

Conventionally, a dynamic friction coefficient test at the time of point contact of a film has not been performed. The kinetic coefficient of friction test of a typical film is performed by surface contact.

In this case, the dynamic friction coefficient of the cellulose ester film at a surface contact load of 300 g (visual area 4 × 63 × 63 mm ² ): μ ：, and the dynamic friction at a surface contact load lOOOOg (apparent area 63 × 63 mm ² ). The coefficient A is measured, for example, as follows.

[0059] Measurement method

Use a surface contact tester TYPE14S, TYPE18L, TYPE32, Trispo Station, and similar models manufactured by Shintoi Dangaku Co., Ltd., and a dynamic friction coefficient test at the time of surface contact. It can be obtained by applying the above load and performing a dynamic friction coefficient test. Various optional tools can be used for the surface contact indenter. The dynamic friction coefficient and the static friction coefficient can be obtained by a predetermined method specified for the device.

[0060] The above measuring method is an example, and the present invention is not limited to this method, and the dynamic friction coefficient and the static friction coefficient can be obtained as appropriate by a similar method using a similar measuring instrument. It is.

[0061] In the cellulose ester film according to the present invention, the arithmetic average roughness of the film: Ra, the ten-point average roughness: Rz, and the average interval between local peaks: Sm are respectively within the following ranges.

[0062] 9. Onm≤Ra≤l l. Onm

150nm≤Rz≤250nm

10nm≤Sm≤300nm

By maintaining the arithmetic average roughness (Ra), ten-point average roughness (Rz), and average distance between local peaks (Sm) of the film within the above ranges, the film slipperiness related to winding quality can be improved. It can be retained, for example, even if the winding diameter of the cellulose ester film is increased and the force applied to the wound film is increased, the deterioration of the film appearance and the slipperiness between the films, that is, the deterioration of the winding quality is prevented. can do.

In the cellulose ester film according to the present invention, the average particle diameter of the matting agent fine particles in the film is 100 to 500 nm, and the distance between the matting agent fine particles is 0.3 to 3 / ζπι.

Here, if the average particle diameter of the matting agent fine particles in the film is less than 100 nm, It is not preferable because the number of contact points when the lumps are overlapped decreases and the frictional resistance between the films increases, and as a result, the appearance of the rolled film tends to be deteriorated.

. On the other hand, if the average particle diameter of the matting agent fine particles exceeds 500 nm, the transparency of the film is deteriorated, and the appearance of the film is deteriorated. On the other hand, if the distance between the matting agent fine particles is less than 0.3 μm, the transparency of the film deteriorates and the appearance of the film deteriorates, which is not preferable. When the distance between the fine particles of the matting agent exceeds 3 / zm, the number of contact points when the films are overlapped is reduced, and the frictional resistance between the films is increased. It is not preferable because it is easy to cause.

Further, in the cellulose ester film according to the present invention, the average particle diameter of the fine particles of the matting agent in the film is 500 to 1000 nm, and the distance between the fine particles of the matting agent is 1 to 5 μm.

Here, if the average particle diameter of the matting agent fine particles in the film is less than 500 nm, the number of contact points when the films are overlapped is reduced, and the frictional resistance between the films is increased. The appearance of the film is likely to deteriorate, which is not preferable. On the other hand, if the average particle diameter of the matting agent fine particles exceeds 100Onm, the transparency of the film is deteriorated, and the appearance of the film is deteriorated. On the other hand, if the distance between the fine particles of the matting agent is less than 1 μm, the transparency of the film deteriorates and the appearance of the film deteriorates, which is not preferable. On the other hand, if the distance between the matting agent fine particles exceeds 5 / zm, the number of contact points when the films are superimposed decreases, and the frictional resistance between the films increases.As a result, the appearance of the rolled film deteriorates. It is not preferable because it becomes easier.

Hereinafter, the present invention will be described specifically.

[0068] Examples of the cellulose ester which is the main component of the cellulose ester film of the present invention include cenorellost triacetate (TAC), cenorellose diacetate, cenorellose acetate butyrate, and cellulose acetate propionate (CAP). In the case of cellulose triacetate, cellulose base acetate with a degree of polymerization of 250 to 400 and a bound acetic acid content of 54 to 62.5% is preferred, and a base strength of 58 to 62.5% bound acetic acid is preferred. preferable. Cellulose triacetate is either cellulose triacetate with synthetic cotton linter and synthetic cellulose triacetate with wood pulp. Or a mixture of them. Preferably, the cellulose ester is substantially cellulose triacetate.

[0069] In the method of the present invention, the solvent used for dissolving the cellulose ester may be used alone or in combination, but it is preferable to use a mixture of a good solvent and a poor solvent from the viewpoint of increasing the production efficiency. A larger amount of a good solvent is preferred in terms of the solubility of the cellulose ester and the reduction of film foreign matter due to minute insoluble matter. The mixing ratio of the good solvent and the poor solvent is preferably in the range of 70 to 98% by weight of the good solvent and 30 to 2% by weight of the poor solvent.

[0070] Here, the good solvent and poor solvent used in the present invention are defined as a good solvent that dissolves the cellulose ester used alone or a poor solvent that swells or does not dissolve alone. I have.

[0071] The good solvent used in the present invention is not particularly limited. For example, in the case of cellulose triacetate (TAC), organic halogenated compounds such as methylene chloride (DCM), dioxolanes, and cellulose acetate propionate In the case of nate (CAP), examples include methylene chloride (DCM), acetone, and methyl acetate (MA). The poor solvent is not particularly limited, but for example, methanol, ethanol (EtOH), i-propyl alcohol, n-butanol, cyclohexane, acetone, cyclohexanone and the like are preferably used.

[0072] Examples of non-chlorinated organic solvents for cellulose esters include acetone, methyl acetate (MA), cyclohexanone, ethyl formate, 1,3-dioxolan, 2,2,2 trifluoroethanol, 2,2,3,3 3-tetrafluoro-1-propanol, 1,3 difluoro-2-propanol, 1,1,1,3,3,3 hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3 hexafnoroleol 2 Prono nole, 2,2,3,3,3 Pentafunoleol 1 propanol and the like. These solvents may be used alone or in combination of two or more.

[0073] Among these non-chlorine-based organic solvents, methyl acetate (MA) and acetone are the most preferable. Methyl acetate and acetone can provide a film with good solubility and excellent transparency.

[0074] In the present invention, the solution of the cellulose ester may have improved solubility, adjusted viscosity, and improved dryness. A lower alcohol having 1 to 6 carbon atoms may be contained for the purpose of adjusting the drying speed, promoting gelation when the solution is cast, and the like. These lower alcohols include, for example, methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butanol, isobutyl alcohol, 2-butanol, t-butyl alcohol, cyclohexanol and the like. Among them, methanol, ethanol and 1-butanol are preferred. These lower alcohols are preferably contained in an amount of 2% by weight or more and 20% by weight or less based on the total organic solvent. A cellulose ester solution containing a lower alcohol having 1 to 6 carbon atoms can be used as a support for casting in casting, where the strength of the film is strong even in a state where a large amount of residual solvent is contained. It is easy to strip off the force on the drum.

[0075] The cellulose ester solution is obtained by putting a cellulose ester and a solvent, which are adjusted by a usual method, into a container and stirring and mixing at room temperature or under a temperature condition at which the solvent does not boil. It is preferable that the stirring and mixing be performed by an apparatus and a method in which no liquid film remains inside the container. Further, the inside of the container may be filled with an inert gas such as nitrogen gas to suppress the decomposition. If necessary, the mixture may be stirred and mixed under pressure using a pressurized container or the like.

[0076] The cellulose ester concentration in the solution is preferably as high as possible from the viewpoint of drying efficiency during film formation. On the other hand, when the concentration is too high, the viscosity of the solution is too large, and the flatness of the obtained film may be deteriorated. In consideration of these points, the cellulose ester concentration of not preferred solution is in the range of 15 weight ^_0/0 forces 40 weight ^_0/0. Further, a range of 20% by weight to 35% by weight is preferable.

[0077] The viscosity of the cellulose ester solution is preferably adjusted to a range of 5P (boise) force to 500P (boise), as long as it is within a range that can be cast during film formation. .

[0078] The heating temperature after the addition of the solvent is preferably in the range of not less than the boiling point of the solvent used and not boiling the solvent, for example, in the range of not less than 60 ° C and not less than 80 to 110 ° C. Is preferred. The pressure is determined so that the solvent does not boil at the set temperature.

[0079] After dissolution, the force for extracting the container force while cooling or the container force is also extracted by a pump or the like, cooled by heat exchange, etc., and provided for film formation.

[0080] The cellulose ester film according to the present invention further comprises a compound represented by the general formula [I]

[0081] BO

A-O-P-O-C ■■■ [I]

II

o

(Wherein, A, B and C represent a phenyl group or a biphenyl group, and at least two of A, B and C are biphenyl groups) . In particular, tris-biphenyl phosphate (TBP) has the effect of improving the hydrophobicity of the film and, as a result, improving the slipperiness.

[0083] The cellulose ester film according to the present invention further has a general formula [I]

[0084]

B O

A-O-P-O-C ■■■ [I]

II

o

[0085] In the compound represented by the formula, A, B and C represent a fuel group or a biphenyl group, and a compound in which at least two of A, B and C are a biphenyl group; In the formula, A, B and C represent a phenyl group or a biphenyl group, and at least two of A, B and C contain a compound which is a phenyl group.

[0086] The plasticizer that can be used in the present invention is not particularly limited, and for phosphate esters, triphenyl phosphate (TPP), biphenyl diphenyl phosphate (BDP), tricresinole phosphate, and crezinoresife. For phthalic acid esters such as -norephosphate, otatinolefie-norephosphate, trioctylphosphate, tributylphosphate, etc., use dimethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, and di-2-ethyl. Xyl phthalate, butyl phthalyl butyl diolate, ethyl phthalyl ethyl cholate (EPEG), methyl phthalyl ethyl cholate And butylphthalylbutyldalicholate and the like can be used.

[0087] Two or more of the above plasticizers may be used in combination, if necessary. The inclusion of these plasticizers is particularly preferable because a film having excellent dimensional stability and water resistance can be obtained.

[0088] In the present invention, in order to keep the water absorption and the water content within specific ranges, the preferred amount of the plasticizer to be added is 12% by weight or less based on the weight of the cellulose ester. When two or more plasticizers are used in combination, it is sufficient that the total amount of these plasticizers is 12% by weight or less.

[0089] The cellulose ester film according to the present invention further contains a compound comprising a polyhydric alcohol ester of an aliphatic polyhydric alcohol and one or more monocarboxylic acids. The content of the polyhydric alcohol ester is 4. against cellulose esters 5 to 12.5 wt ^_0/0, preferably 6-12 wt%, more preferably 7-11 wt%.

In the cellulose ester film of the present invention, the monocarboxylic acid is preferably a compound having an aromatic ring or a cycloalkyl ring in the molecule.

[0091] In the cellulose ester film of the present invention, the aliphatic polyhydric alcohol is preferably dihydric to 20-hydric.

[0092] As described above, it is considered that the use of the polyhydric alcohol ester greatly contributes to the reduction of the amount of the conventional plasticizer.

[0093] Next, the aliphatic polyhydric alcohol ester used in the present invention will be described. The aliphatic polyhydric alcohol ester is an ester of a dihydric aliphatic alcohol of 2 to 20 and one or more monocarboxylic acids. It is.

[0094] The aliphatic polyhydric alcohol used in the present invention is a divalent to 20-valent alcohol represented by the following general formula [式].

[0095] R one (OH) n

In the formula, R represents an n-valent aliphatic organic group, n represents a positive integer of 2 to 20, and an OH group represents an alcoholic and Z or phenolic hydroxyl group.

[0096] Here, the n-valent aliphatic organic group includes an alkylene group (for example, a methylene group, an ethylene group

, Trimethylene group, tetramethylene group, etc.), alkelene group (for example, eturene group, etc.), Examples include a kylene group (eg, an ethylene group), a cycloalkylene group (eg, a 1,4-cyclohexandyl group), and an alkanthryl group (eg, a 1,2,3 propanetriyl group). . The n-valent aliphatic organic group includes those having a substituent (eg, a hydroxy group, an alkyl group, a halogen atom, etc.).

[0097] n is preferably 2 to 20! /. Preferred! / Examples of polyhydric alcohols include, for example, adtol, arabitol, ethylene glycolone, diethylene glycol, triethylene glycol, tetraethylene dalicol, 1,2 propanediol, 1,3 propanediol, dipropylene glycol. , Tripropylene glycol, 1,2 butanediol, 1,3 butanediol, 1,4 butanediol, dibutylene glycol, 1,2,4 butanetriol, 1,5 pentanediol, 1,6 hexanediol, hexane Triol, galacti tonole, mannitol, 3-methylpentane-1,3,5 trionyl, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol and the like can be mentioned. In particular, triethylene glycol, tetraethylene dalicol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferred.

(Monocarboxylic acid)

In the present invention, the monocarboxylic acid in the polyhydric alcohol ester is not particularly limited, and known aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids can be used. It is preferable to use an alicyclic monocarboxylic acid or an aromatic monocarboxylic acid from the viewpoint of improving moisture permeability and retention.

[0098] Examples of preferable monocarboxylic acids include the following. The present invention is not limited to these.

[0099] As the aliphatic monocarboxylic acid, a fatty acid having 1 to 32 carbon atoms and having a straight chain or a side chain can be preferably used. The number of carbon atoms is more preferably 1 to 20. 1 to: LO is particularly preferred. When acetic acid is contained, the compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and other monocarboxylic acids, which are preferred.

[0100] Preferably, the aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, cabronic acid, enanthic acid, power prillic acid, pelargonic acid, power pric acid, and 2-ethylhexane power. Rubonic acid, pendecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, araquinic acid, behenic acid, lignoceric acid, serotinic acid, heptacosanoic acid, montanic acid, Saturated fatty acids such as melisic acid and rataceric acid, and unsaturated fatty acids such as pendecylene acid, oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid can be mentioned. These may further have a substituent.

[0101] Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof.

Examples of preferred aromatic monocarboxylic acids include those obtained by introducing an alkyl group into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and benzene such as biphenylcarboxylic acid, naphthalenecarboxylic acid and tetralincarboxylic acid. An aromatic monocarboxylic acid having two or more rings or a derivative thereof can be given. Especially preferred is benzoic acid.

(Polyhydric alcohol ester)

The molecular weight of the polyhydric alcohol ester used in the present invention is not particularly limited, but is more preferably from 350 to 750, preferably from 300 to 1500. A larger one is preferred in terms of retention, and a smaller one is preferred in terms of compatibility with the cellulose ester.

[0103] In the present invention, the carboxylic acid in the polyhydric alcohol ester may be one type or a mixture of two or more types. Further, all the OH groups in the polyhydric alcohol may be esterified, or some of them may be left as OH groups. It is preferable to have three or more aromatic rings or cycloalkyl rings in the molecule!

[0104] Examples of the polyhydric alcohol ester used in the present invention are shown below.

[0105] [Formula 9]

C ₄ Hg--. CH ₂ -CH ₂ -0 ^ ~ C-CijHg OO

C ₄ H ₉ -C-0 -CH ₂ CH— 0¾ CC ₄ H ₉ II \ I No 3 II

O CH ₃ O

C _a H ₁₇ -C-0- ^ CH ₂ CH— O ^-C- C, H ₁₇ O CH ₃ O

^{'f O- ° - CH2 i C} H H -, °) Tf Or- λ ~'

1]

Among the above polyhydric alcohol esters, trimethylolpropane tribenzoate (TMP TB), trimethylolpropane triacetate, trimethylolpropane tripropionate, dipropylene glycol dibenzoate, tripropylene glycol dibenzoate, 1,3-dibutylene glycol Dibenzoate, tetraethylene glycol dibenzoate, Mixed esters of rimethylolpropane with acetic acid and benzoic acid, esters of trimethylolpropane with cyclohexanecarboxylic acid, mixed esters of trimethylolpropane with acetic acid and cyclohexanecarboxylic acid, 3-methylpentane 1, 3, 5 Ester of triol and cyclohexancarboxylic acid, 3-methylpentane 1,3,5 Triol and benzoic acid, xylitol and benzoic acid, xylitol and cyclohexanecarboxylic acid Preferred,.

[0110] The amount of the polyhydric alcohol ester used is preferably 4.5 to 12.5% by weight, more preferably 6 to 12% by weight, particularly preferably 7 to: L based on the cellulose ester. 1% by weight.

[0111] The cellulose ester film according to the present invention contains additives such as an ultraviolet absorber, in addition to the cellulose ester, the solvent, and the compound composed of the polyhydric alcohol ester.

[0112] Additives such as polyhydric alcohol ester compounds and ultraviolet absorbers may be mixed with a solvent in advance, dissolved or dispersed, and added to the solvent before dissolving the cellulose ester. It may be added to the dope after dissolution.

[0113] In the present invention, the polyhydric alcohol ester has a plasticizer function, and such a polyhydric alcohol ester and a conventional plasticizer can be used simultaneously. In that case, as described above, the polyhydric alcohol ester can be used in a range of 4.5 to 12.5% by weight based on the cellulose ester. The total amount of the polyhydric alcohol ester and the plasticizer is It is preferably 12.5% by weight or less based on the weight of cellulose ester. In this case, the amount of the plasticizer used is preferably 8.0% by weight or less based on the cellulose ester. Above all, the amount of polyhydric alcohol ester used is preferably 7% by weight or more based on the cellulose ester. Furthermore, the amount of plasticizer used is 5.5% by weight or less based on the cellulose ester. Is preferred. The reason for this is that the use of the polyhydric alcohol ester makes it possible to reduce the amount of the conventional plasticizer used, so that the effects of the present invention can be exhibited.

[0114] In the cellulose ester film, a phosphate ester compound, a phthalate ester compound, or a polyhydric alcohol composed of a fatty acid polyhydric alcohol and one or more monocarboxylic acids is used. Ester power Compound power Contains at least one selected from the group, and the total content of the compound relative to the cellulose ester film is 8.0% by weight or more and 13% by weight or less.

[0115] Here, if the total content of the above compounds with respect to the cellulose ester film is less than 8.0% by weight, the effect of the present invention is undesirably reduced. On the other hand, if it exceeds 13% by weight, dimensional stability deteriorates, which is not preferable.

[0116] Next, the ultraviolet absorber that can be used in the present invention is not particularly limited, but is excellent in the ability to absorb ultraviolet light having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of the liquid crystal, and has good liquid crystal display properties. Those which absorb as little as possible visible light having a wavelength of 400 nm or more from the point are preferably used.

[0117] Commonly used compounds include, for example, oxybenzophenone-based compounds, benzotriazole-based compounds, salicylate-based compounds, benzophenone-based compounds, cyanoatalylate-based compounds, nickel complex-based compounds, and the like. Not limited.

[0118] Further, fine particles which can be added as a matting agent to the cellulose ester film of the present invention as a matting agent for the purpose of improving slipperiness and preventing blocking after winding may be added to the main dope. It is preferable to add it from the viewpoint of productivity. Add to the additive solution and add to the film. The fine particles may be contained in the main dope, but any fine particles can be used.

[0119] Examples of the fine particles used in the present invention include inorganic compounds such as silicon dioxide, titanium dioxide, titanium oxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, and calcined kaic acid. Mention may be made of calcium, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Fine particles of zirconium-zinc oxide are commercially available, for example, under the trade name of AEROSIL R976 and R811 (both manufactured by Nippon AEROSIL CO., LTD.) And can be used. Among them, fine particles containing silicon are particularly preferable because of their low turbidity. Examples of these are those marketed under the trade names AEROSIL R972, R972V, R974, R812, 200, 200V, 300, R202, 0X50, TT600 (all manufactured by Nippon Aerosil Co., Ltd.). can do. Sarako, primary average particle size of silicon dioxide fine particles Is preferably 20 nm or less and an apparent specific gravity of 70 gZ liter or more. Examples of fine particles of silicon dioxide that satisfy these are, for example, AEROSIL 200V and AEROSIL R972V, which are particularly preferred because they have a large effect of lowering the coefficient of friction while keeping the turbidity of the film low.

[0120] In the present invention, the fine particles are used in an amount of 0.04 to 0.4% by weight based on the cellulose ester. Preferably, it is 0.05-0.3% by weight, more preferably 0.05-0.2% by weight.

[0121] In the present invention, the dope obtained by dissolving the cellulose ester is cast on a support (casting step), and then heated to remove a part of the solvent (drying step on the support). The cellulose ester film is peeled off from the support, and the peeled film is dried (film drying step) to obtain a cellulose ester film.

[0122] In the casting process, a belt-shaped or drum-shaped stainless steel mirror-finished support is used. In the casting process, the temperature of the support is generally in the range of 0 ° C to a temperature lower than the boiling point of the solvent. It is more preferable to cast on a support at 5 to 15 ° C., which is preferable, since the time limit for peeling can be increased by gelling.

[0123] In the on-substrate drying step, the dope is cast, once gelled, and when the time from casting to peeling is 100%, the dope temperature is set to 40 ° C within 30% of the casting. By setting the temperature to ~ 70 ° C, the evaporation of the solvent is accelerated, the film can be peeled off from the support sooner, and the peeling strength is further increased. 70 ° C is more preferable. It is preferred to maintain this temperature above 20%, more preferably above 40%.

[0124] Drying on the support is preferably performed at a residual solvent amount of 60% to 150%, and the strength of the support is also preferably reduced to 80 to 120% because the peel strength from the support is reduced. It is preferable that the temperature of the dope at the time of peeling be 0 ° C to 30 ° C because the base strength at the time of peeling can be increased and the base can be prevented from breaking at the time of peeling. Is more preferred.

[0125] In the film drying step, the film peeled from the support is further dried, and the amount of the residual solvent is 3% by weight or less, preferably 1% by weight or less, more preferably 0.5% by weight or less. Is preferable for obtaining a film having good dimensional stability. In the film drying step, generally, a method of drying while transporting a film by a roll suspension force, a pin tenter method, or a clip tenter method is employed. For a member for a liquid crystal display, it is preferable to dry the tenter method while maintaining the width in order to improve dimensional stability.

[0126] The means for drying the film is not particularly limited and is generally performed using hot air, infrared rays, a heating roll, microwaves, or the like. It is preferable to use hot air in terms of simplicity. The drying temperature is preferably in the range of 40 to 150 ° C and divided into 3 to 5 stages, and it is preferable to increase the temperature gradually.It is preferable to perform the drying in the range of 80 to 140 ° C for dimensional stability. More preferred for better. The steps from the casting to the post-drying may be performed under an air atmosphere or under an inert gas atmosphere such as nitrogen gas.

[0127] The winding machine related to the production of the cellulose ester film of the present invention is a commonly used winding machine, such as a constant tension method, a constant torque method, a taper tension method, and a program tension control method with a constant internal stress. Can be wound by the winding method

[0128] The thickness of the cellulose ester film according to the present invention is not particularly limited, but is usually 100 m or less because it is used for a liquid crystal display element used for an LCD, that is, a protective film for a polarizing plate. Among them, a cellulose ester film having a thickness of 20 to 80 / ζπι is preferred.

As a method for producing a polarizing plate, a general method may be used. Hereinafter, the polarizing plate of the present invention and a liquid crystal display device using the same will be described.

[0130] As the polarizer used for the polarizing plate of the present invention, a conventionally known polarizer can be used.

For example, a film made of a hydrophilic polymer such as polybutyl alcohol and stretched by treating it with a dichroic dye such as iodine, or a film obtained by treating and orienting a plastic film such as chloride chloride is used. . The polarizer thus obtained is laminated with a cellulose ester film.

[0131] The polarizing plate of the present invention is configured such that an optical compensation film made of a cellulose ester film is laminated on at least one side of a polarizer. In the case of only one side, cellulose having no liquid crystal layer coated on the other side is provided. Ester film supports and other transparent supports Or use cellulose triacetate (TAC) film! /.

[0132] The polarizing plate thus obtained may be provided on one surface of the liquid crystal cell or on both surfaces thereof. When provided on one side, an optical compensation film made of a cellulose ester film can be attached to the polarizer closer to the liquid crystal cell to obtain a liquid crystal display device.

Example

Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Examples 1-3 (Preparation of dope solution)

A dope solution of cellulose triacetate (TAC) was prepared as follows.

[0134] Cellulose triacetate (degree of acetyl substitution 2.88) 100 parts by weight

Tinuvin T—326 (Ciba Specialty Chemicals) 1 part by weight

Triphenyl phosphate (TPP) (phosphate ester plasticizer)

Ethyl phthalyl ethyl cholate (EPEG) (phthalate plasticizer) Trimethylolpropane tribenzoate (TMPTB) (polyhydric alcohol ester) Total of 10 parts by weight of plasticizer and Z or polyhydric alcohol ester AEROSIL 200V 0.09 parts by weight

(Diacidi-Daily Silicone matting agent, manufactured by Nippon Adirozil Co., Ltd.)

320 parts by weight of methylene chloride (DCM)

320 parts by weight of methyl acetate (MA)

20 parts by weight of ethanol (EtOH)

With the above materials, triphenyl phosphate (TPP) (phosphate plasticizer), which is a plasticizer for producing cellulose triacetate film, and ethyl phthalyl ethyl glycolate (EPEG) (phthalate plasticizer) ) And the polyhydric alcohol ester trimethylolpropane tribenzoate (TMPTB), as shown in Table 1, to prepare three types of dope materials.

[0135] Then, each of these materials was put into a closed container, and completely dissolved with stirring while keeping the temperature at 80 ° C under pressure. (Preparation of film sample)

After the above-mentioned dope solution was filtered, it was cast on a support made of a stainless steel endless belt from a casting die at a dope temperature of 33 ° C. using a belt casting device (not shown). The web formed on the support was released on the support by a release roll, and dried while being conveyed by a number of rolls. At this time, the film was dried while being stretched in the width direction using a clip tenter. After drying, the film was wound into a roll to obtain three types of cellulose triacetate films having a thickness of 40 m.

[0136] Table 1 below shows the types of plasticizers and polyhydric alcohol esters used, the dynamic friction coefficient at a surface contact load of 300 g (apparent area 63 X 63 mm ² ): μ, and a surface contact load of 10 OOg (apparent). The dynamic friction coefficient in an area of 63 X 63 mm ² ): the measurement results of A and the calculation results of the ratio of AZB are shown in Table 1.

[0137] Here, dynamic friction on the surface contact load 300 g (see force 4 Na area 63 X 63 mm ²⁾ of a cellulose triacetate film coefficient: mu beta, and dynamic friction coefficient at the surface contact load LOOOg (apparent area 63 X 63mm 2): The measurement test of A was performed as follows.

[0138] Measurement method

Comparative Examples 1-3

For comparison, the force for producing a cellulose triacetate film having a film thickness of 40 m in the same manner as in Example 1 above.In Comparative Examples 1 and 2, the dynamic friction coefficient B) at a surface contact load of 300 g and the surface contact Ratio with dynamic friction coefficient A) under load lOOOOg: AZ B force This is outside the scope of the present invention. In Comparative Example 3, the case where the ratio was less than 0.8, which is out of the range of the present invention, was shown.

(Evaluation of winding quality) The winding quality of each of the cellulose triacetate films of Examples 1 to 3 and Comparative Examples 1 and 2 according to the present invention was evaluated. Here, as a method of evaluating the winding quality, the appearance of the wound film of each cellulose triacetate film was confirmed, and according to the number observed in the protruding portion in the form of a protrusion, 0 to 5 were rated as A, and 6 to 10 were evaluated as A. B, 11 to 20 pieces, and 21 or more pieces were D.

(Measurement of arithmetic average roughness: Ra, ten-point average roughness: Rz, average interval of local peaks: Sm) In addition, each of the cellulose triacetate films obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was measured. lm ² is sampled, and the average value of the arithmetic average roughness (Ra), the average value of the ten-point average roughness (Rz), and the average interval (Sm) of the local peaks on both sides of the film are determined according to the method of JIS K7125. It was measured.

[0139] That is, using a film surface roughness measuring device (WYKO-NT1100) manufactured by Veeco, at a magnification of 20 times, both sides of the film were measured at three points each, and the average value was arithmetically averaged. The roughness (Ra) and the ten-point average roughness (Rz) were used. The point from the peak to the valley of the roughness curve was defined as the transition point, and the average value of the distance from the transition point to the next transition point was defined as the average distance between local peaks (Sm). The results obtained are summarized in Table 1 below.

[0140] [Table 1]

As is clear from the results of Example 1, in Examples 1-3 of the present invention, The winding quality of the tate film is good, and the film has excellent physical properties, which indicates that it is suitable for a polarizing plate protective film. In Examples 1 to 3 of the present invention, the cellulose triacetate film had an arithmetic average roughness (Ra) of 9.5 nm, a ten-point average roughness (Rz) of 170 nm, and an average interval (Sm) of local peaks. ) Is 250 nm, it is estimated that the contact area when the films are overlapped is in an appropriate state, the friction coefficient between the films is within the range of the present invention, and the winding quality is good. is there.

[0142] In contrast, in Comparative Examples 1 and 2, it was found that the winding quality of the cellulose triacetate film was poor, the surface physical properties of the film were poor, and the film was not suitable for a polarizing plate protective film. In Comparative Examples 1 and 2, the arithmetic mean roughness (Ra) of the cellulose triacetate film was as low as 6. Onm and 8. Onm, and the ten-point average roughness (Rz) force was as low as Onm and lOnm. On the contrary, the average distance (Sm) between the local peaks is estimated to be small because the contact area when the films are overlapped is small because of the force of increasing 650 nm and 400 nm. And the winding quality is deteriorated.

Further, in Comparative Example 3, the arithmetic average roughness (Ra) of the cellulose triacetate film was as extremely high as 13.Onm, and the ten-point average roughness (Rz) was 300 nm. The uniform spacing (Sm) was as low as 100 nm, the winding quality was good, the film was poor in smoothness, and it was not practically usable.

Examples 4 and 5

In the same manner as in Example 1, two types of cellulose triacetate films having a thickness of 40 m were obtained.

[0144] Table 2 below shows the types of plasticizers and polyhydric alcohol esters used, and the dynamic friction coefficient at a surface contact load of 300 g (apparent area 63 X 63 mm ² ): μΒ, and a surface contact load of 10 OOg (apparent). The dynamic friction coefficient in an area of 63 X 63 mm ² ): the measurement results of A and the calculation results of the ratio of AZB are also shown.

Comparative Example 4

For comparison, the ability to produce a cellulose triacetate film having a film thickness of 40 m in the same manner as in Example 4 above. In Comparative Example 4, the AZw B force in Comparative Example 3 was outside the scope of the present invention. The case where it is less than 8 is shown. (Evaluation of winding quality)

For each of the cellulose triacetate films of Examples 4 and 5 and Comparative Example 4 according to the present invention, the winding quality of the film was evaluated in the same manner as in Example 1 above, and the obtained results are shown in Table 2. Indicated.

For each of the cellulose triacetate films obtained in Examples 4 and 5, and Comparative Example 4, the average particle diameter of the matting agent (fine particles of silicon dioxide) was measured, and the particle size of the fine particles was measured. The distance was measured. The distance between particles was measured by observing the film surface and cross section with a scanning electron microscope. That is, the average of the interparticle distance per observation point on a 20 m square plane was calculated. In addition, the average distance between particles was determined for five observation points. The average of the values thus obtained was defined as the distance between particles. The obtained results are summarized in Table 2 below.

[Table 2]

As is clear from the results in Table 2 above, according to the cellulose triacetate films of Examples 4 and 5 of the present invention, the winding quality of the cellulose triacetate film was good, It turns out that the film has excellent physical properties and is suitable for a protective film for a polarizing plate. The average particle diameter of the matting agent (silicon dioxide fine particles) in the cellulose triacetate film was 250 nm in Example 4 and 700 nm in Example 5. The distance between the fine particles in the film was 3 μm in each case.

On the other hand, in Comparative Example 4, it was found that the winding quality of the cellulose triacetate film was poor, the surface physical properties of the film were poor, and the film was not suitable for a polarizing plate protective film. Further, in Comparative Example 4, the average particle diameter of the matting agent (dioxygen silicon dioxide fine particles) in the cellulose triacetate film was 1200 nm, and the distance between the fine particles in the film was 2 μm.

[0149] As a result, according to the cellulose triacetate films of Examples 4 and 5 of the present invention, the contact area when the films were overlapped with each other was more appropriate than that of the cellulose triacetate film of Comparative Example 4. It is estimated that the coefficient of friction between the films is within the range of the present invention, and the winding quality is good.

Industrial applicability

[0150] The cellulose ester film of the present invention is useful as a protective film for a polarizing plate of a liquid crystal display device (LCD), and particularly, a cellulose ester film capable of improving winding quality with a rolled product of 5000 m or more. In addition, it is possible to provide a cellulose ester film capable of suppressing deterioration of winding quality even with a wound product having a large load such as an increase in winding diameter of 5000 m or more.

Claims

The scope of the claims

[1] A cellulose ester film containing a matting agent. The coefficient of dynamic friction at a surface contact load of 300 g (apparent area 63 X 63 mm ² ) is B, and the surface contact load lOOOOg (apparent area 63 X

When the dynamic friction coefficient at 63 mm ² ) is / z A,

A cellulose ester film, characterized by satisfying 0.8 ≦ μΑ / μ 3 ≦ 1.3.

[2] The arithmetic average roughness of the film: Ra, the ten-point average roughness: Rz, and the average distance between local peaks: Sm, respectively, are within the following ranges, respectively. Item 6. Cellulose estenoleinolem.

9. Onm≤Ra≤l l. Onm

150nm≤Rz≤250nm

10nm≤Sm≤300nm

[3] The method according to claim 1, wherein the average particle diameter of the matting agent fine particles in the film is 100 to 500 nm, and the distance between the matting agent fine particles is 0.3 to 3 m. The mouth of the mouth is Estenolefuinolem.

[4] The matting agent according to claim 1, wherein the average particle diameter of the matting agent fine particles in the film is 500 to 1000 nm, and the force between particles of the matting agent fine particles is ^ to 5 μm. The mouth of the mouth is Estenolefuinolem.

[5] Furthermore, the general formula [I]

[Chemical 1]

B O

A-O-P-O-C… [I]

II

o

(Wherein, A, B and C represent a phenyl group or a biphenyl group, and at least two of A, B and C are biphenyl groups). The cellulose ester film according to claim 1, wherein:

[6] Furthermore, the general formula [I] [Chemical 2]

B O

A-O-P-O-C ■■■ [I]

II

In the compound represented by o, A, B and C represent a phenyl group or a biphenyl group, and a compound in which at least two of A, B and C are a biphenyl group; , A, B and C each represent a phenyl group or a biphenyl group, and at least two of A, B and C contain a compound which is a phenyl group. Senorelose estenolefuinolem according to paragraph 1.

[7] Further, a compound comprising a polyhydric alcohol ester of an aliphatic polyhydric alcohol and one or more monocarboxylic acids is contained in an amount of 4.5 to 12.5% by weight relative to the cellulose ester film. 2. The cellulose ester finolem according to claim 1, wherein:

[8] The monocarboxylic acid force. The cellulose ester film according to claim 7, which is a compound having an aromatic ring or a cycloalkyl ring in a molecule.

[9] The cellulose ester film according to claim 7, having an aliphatic polyhydric alcohol power of 2 to 20.

[10] The cellulose ester film according to claim 7, having an aliphatic polyhydric alcohol power of 2 to 3 valences.

[11] The cellulose ester film according to claim 7, wherein the aliphatic polyhydric alcohol has 4 or more carbon atoms.