TWI447444B - An optical film, a method for producing an optical film, a polarizing plate using the same, a liquid crystal display device, and a compound - Google Patents

Description

Optical film, method for producing optical film, polarizing plate using the same, liquid crystal display device, and compound

The present invention relates to an optical film, a method for producing an optical film, a polarizing plate using the same, a liquid crystal display device, and a compound.

In recent years, as a thin display replacing a CRT display, emphasis has been placed on a liquid crystal display device (liquid crystal display), a plasma display, and an organic EL display. These new generations of displays carry a large number of optical films, but due to their thinness, the various functional performance improvements required for these optical films are becoming stricter year by year. Therefore, it is expected that an optical film having further improved performance can be achieved.

On the other hand, the development of thin and light notebooks, large screens, and high definition of notebook computers is underway. As a result, the optical film for liquid crystal display devices has become increasingly thinner, wider, and higher in quality. Although various types of resins have been used as optical films for liquid crystal display devices, cellulose esters, polycarbonates, and polyolefins have been used as polarizing plate protective films for optical films. Among them, cellulose ester films using cellulose esters are also more overwhelming.

These cellulose ester films have heretofore been produced by solution casting. The solution casting method is a film forming method in which a solution in which a cellulose ester is dissolved in a solvent is cast to obtain a film shape, and then a solvent is evaporated and a solvent is obtained. Since the film formed by the solution casting method has a high planarity, a high-definition liquid crystal display having no unevenness can be obtained by using this.

However, the solution casting method requires a large amount of organic solvent, causing a problem of causing a large environmental load. From the viewpoint of the solubility characteristics, the cellulose ester film is formed by using a halogen-based solvent having a large environmental load, so that the use of a solvent is particularly required to be reduced, and it is difficult to increase the yield of the cellulose ester by solution casting. film.

Further, since it is necessary to remove the solvent remaining in the inside of the film, the equipment investment and the manufacturing cost of the manufacturing processes such as the drying process, the drying energy, and the evaporation and recovery of the solvent are increased, and the reduction of these becomes an important problem.

The cellulose ester film for optical use has a manufacturing load and a device load accompanying the use of the solvent in the production step, and the optical properties and mechanical properties are also in an insufficient state.

In recent years, as a silver salt photograph or a polarizing plate protective film, an attempt has been made to melt a film of a cellulose ester. The cellulose ester is a polymer having a very high viscosity at the time of melting, and the glass transition temperature is also high, so that after the cellulose ester is melted When it is extruded from a mold, it is difficult to flatten even if it is cast on a cooling drum or a cooling conveyor belt, and has a problem that optical characteristics and mechanical properties are lower than that of a solution cast film (see, for example, Patent Document 1).

Therefore, these cellulose ester films are generally wound into a winding core and stored and conveyed as a film original roll. Therefore, when the melt-film-formed film is stored for a long period of time in the state in which the film is wound up by the winding core, there is a malfunction of the horseback failure or the so-called core transfer on the core portion of the original film roll. There is a problem of collapse on the film during winding.

The so-called horseback fault is that the original film of the film is formed into a U-shape such as a horseback, and a band-shaped convex portion having a pitch of about 2 to 3 cm is formed in the vicinity of the center portion. Since the film is left to be deformed, the polarizing plate is processed. When you see the surface, you will see the problem of deformation. Up to now, the occurrence of horseback failure can be reduced by reducing the dynamic friction coefficient of the bottom materials or adjusting the height of the piping processing (embossing) on both sides.

Further, the core transfer is a failure of the film deformation caused by the unevenness of the core or the film.

These defects have not become an excessive problem on the film produced by the conventional solution casting, but the film produced by the melt film formation has a low planarity and is a serious problem.

Especially in recent years, with the large screen, it is expected that the width of the original film roll can be wider and the winding length can be longer. Therefore, the film becomes more widely curled, or the film original roll load tends to increase, and it is expected to be improved in the case where these troubles are more likely to occur.

[Patent Document 1] JP-A-2006-241428

The present invention has been made in view of the above problems, and an object of the present invention is to provide a film roll which does not leak even when stored for a long period of time, and which does not cause a horseback failure or a convex failure. An optical film for deformation failure, a method for producing an optical film, a polarizing plate using the same, a liquid crystal display device using the polarizing plate, and a novel compound used for the optical film.

As a result of the detailed review by the present inventors, when the cellulose ester contains a specific cinnamic acid ester compound, it is surprisingly known that the haze value is good, and even if it is stored for a long period of time, it is less likely to leak, and no horse is produced. Deformation failure of the original film roll such as back failure or convex failure. Further, it has been found that the optical film of the present invention can be produced by a melt casting method to complete the present invention. Further, it has been found that by using such an optical film, a polarizing plate having good characteristics and a liquid crystal display device can be provided. A novel compound for use in the aforementioned optical film was found.

The above problems of the present invention are achieved by the following constitution.

An optical film comprising at least one of a compound represented by the following general formula (1) and a cellulose ester.

(wherein R ¹ and R ² each independently represent a substituent, R ³ represents a hydrogen atom or an alkyl group, and n represents an integer of 0 to 4. The plural R ¹ may be the same or different).

2. The optical film according to the above-mentioned item 1, which is at least one selected from the group consisting of a hindered phenol compound, a phosphorus compound, a lactone compound, and an acrylate compound.

A method for producing an optical film, characterized in that the optical film according to the above 1 or 2 is produced by a melt casting method.

A polarizing plate characterized in that the optical film according to the above 1 or 2 is contained on at least one surface of a polarizer.

A liquid crystal display device using the polarizing plate according to the above 4th aspect.

6. A compound represented by the following general formula (2).

(wherein R ⁴ to R ⁶ each independently represent an alkyl group, a cycloalkyl group or an aryl group, R ⁷ represents a substituent, and n represents an integer of 0 to 3. The plural R ⁷ may be the same or different).

[Effects of the Invention]

According to the present invention, it is possible to provide an optical film, an optical film manufacturing method, and an optical film which have a good haze value and which are less leaky during long-term storage and which do not cause deformation of a film original such as a horseback failure or a convex failure. A polarizing plate, a liquid crystal display device, and a novel compound used in the optical film.

[Preferred form of the invention]

Hereinafter, preferred embodiments of the present invention will be described in detail, but the present invention is not limited thereto.

The optical film of the present invention is characterized by containing at least one of the compounds represented by the above general formula (1) and a cellulose ester.

"The compound of general formula (1)"

First, the compound of the above general formula (1) of the present invention will be described in detail.

In the formula, R ¹ and R ² each independently represent a substituent, R ³ represents a hydrogen atom or an alkyl group, and n represents an integer of 0 to 4. The plural R ¹ may be the same or different. Specific examples of the substituent include an alkyl group (e.g., methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, pentyl group, hexyl group, octyl group, lauryl group, trifluoromethyl group, etc.), and a ring. An alkyl group (e.g., a cyclopentyl group, a cyclohexyl group, etc.), an aryl group (e.g., a phenyl group, a naphthyl group, etc.), an anthranyl group (e.g., an acetamino group, a benzylamino group, etc.), an alkylthio group (e.g., A) Alkylthio, ethylthio, etc.), arylthio (eg phenylthio, naphthylthio, etc.), alkenyl (eg vinyl, 2-propenyl, 3-butenyl, 1-methyl) Alkyl-3-propenyl, 3-pentenyl, 1-methyl-3-butenyl, 4-hexenyl, cyclohexenyl, etc.), a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, An iodine atom or the like), an alkynyl group (for example, a propynyl group, etc.), a heterocyclic group (for example, a pyridyl group, a thiazolyl group, an oxazolyl group, an imidazolyl group, etc.), an alkylsulfonyl group (for example, a methylsulfonyl group, an ethyl group) Sulfhydryl group, etc., arylsulfonyl (for example, phenylsulfonyl, naphthylsulfonyl, etc.), alkylsulfinyl (such as methylsulfinyl), arylsulfinyl (e.g., phenylsulfinyl, etc.), phosphinyl, fluorenyl (e.g., ethylidene, trimethylethenyl, benzoyl) Anthracenyl, etc., an aminomethyl sulfhydryl group (eg, an amine carbonyl group, a methylamine carbonyl group, a dimethylamine carbonyl group, a butylamine carbonyl group, a cyclohexylamine carbonyl group, a phenylamine carbonyl group, a 2-pyridylamine carbonyl group, etc.), Aminesulfonyl (eg, amine sulfonyl, methylamine sulfonyl, dimethylamine sulfonyl, butylamine sulfonyl, hexylamine sulfonyl, cyclohexylamine sulfonyl, octylamine sulfonate Sulfhydryl, lauryl sulfonyl, phenylamine sulfonyl, naphthylamine sulfonyl, 2-pyridylamine sulfonyl, etc., sulfonamide (eg, sulfonamide, benzene sulfonate) Amino group, etc.), cyano group, alkoxy group (e.g., methoxy, ethoxy, propoxy, etc.), aryloxy (e.g., phenoxy, naphthyloxy, etc.), heterocyclic oxy, decyloxy a base, a decyloxy group (e.g., an ethoxylated group, a benzhydryloxy group, etc.), an amine carbonyloxy group, an amine group (e.g., an amine group, an ethylamino group, a dimethylamino group, a butylamino group, a cyclopentylamino group, 2-ethylhexylamino, dodecylamino, etc.), anilino (eg anilino, chloroanilino, toluidine, anisidine, naphthylamino, 2-pyridylamino, etc.), imine Urea group (eg methylureido, ethylurea, pentylurea, ring) Alkyl urea group, octyl urea group, lauryl urea group, phenyl urea group, naphthyl urea group, 2-pyridylamine urea group, etc.), alkoxycarbonylamino group (for example, methoxycarbonylamino group, benzene) An oxycarbonylamino group, etc., an alkoxycarbonyl group (e.g., a methoxycarbonyl group, an ethoxycarbonyl group, a phenoxycarbonyl group, etc.), an aryloxycarbonyl group (e.g., a phenoxycarbonyl group, etc.), a heterocyclic thio group, Each group such as a thiourea group, a hydroxyl group, or a thiol group. These substituents may be further substituted by the same substituents.

R ³ represents a hydrogen atom or an alkyl group, and specifically has the same meaning as the alkyl group described as the substituent represented by R ¹ and R ² in the above general formula (1).

In the above general formula (1), R ^{1 is} preferably an alkyl group or an alkoxy group, and R ² is an alkyl group, an aryl group, an alkoxycarbonyl group, an aminomethylcarbonyl group, an alkylsulfonyl group or an arylsulfonyl group. The group and the cyano group are preferred, and R ³ is preferably a hydrogen atom. Further, in the above general formula (1), R ² is preferably an alkoxycarbonyl group.

More preferably, it is a compound represented by the above general formula (2).

In the formula, R ⁴ to R ⁶ each independently represent an alkyl group, a cycloalkyl group or an aryl group, R ⁷ represents a substituent, and n represents an integer of 0 to 3. The plural R ⁷ may be the same or different).

In the above general formula (2), R ⁴ to R ⁶ each independently represent an alkyl group, a cycloalkyl group or an aryl group, but specifically, as described in the substituents represented by R ¹ and R ² in the above general formula (1). The alkyl group, the cycloalkyl group or the aryl group is synonymous, and these substituents may be further substituted with the same substituents as the substituents represented by R ¹ and R ^{2 of the} above general formula (1). Further, in the general formula (2), R ⁷ represents a substituent, but specifically, it is synonymous with those described as the substituents represented by R ¹ and R ² in the above general formula (1), and these substituents may be further substituted by the same substituent. Replaced.

Representative specific examples of the compounds represented by the general formula (1) and the general formula (2) of the present invention are shown below, but the present invention is not limited thereto.

Further, the geometrical isomers having the double bond of the structure represented by the above general formula (1) and the general formula (2) as a shaft may be cis or trans.

The compound of the general formula (1) and the general formula (2) of the present invention can be easily synthesized by a known synthesis method described in Japanese Society of Chemistry 711 (1998) or the like.

Hereinafter, the synthesis method of the compound represented by the above general formula (1) and general formula (2) of the present invention will be specifically described, but the present invention is not limited thereto.

Synthesis Example 1-1

(Synthesis of Compound 1-31) via Wittig Reaction

157.4 g of triphenylphosphine was dissolved in 630 ml of toluene, and 117 g of t-butylbromoacetate was added. After standing for 1 hour, the precipitated crude product was washed with toluene to quantitatively obtain a crystal of Intermediate A. To the intermediate A260g, 650 ml of water, 650 ml of toluene, and 73.3 g of sodium carbonate were added, and the mixture was stirred at room temperature for 2 hours. The organic layer was separated, and concentrated under reduced pressure to give crystals of Intermediate B (yield: 90%). Next, 44.8 g of 3,5-di-t-butylsalicylaldehyde was dissolved in 470 ml of methanol, and Intermediate B72g was added thereto. After allowing to stand at room temperature for 1 day, ethyl acetate and water were added to the mixture, and the mixture was washed with water, and the organic layer was evaporated. The obtained crystal was analyzed by 1H-NMR and MASS spectrum, and the exemplified compound 1-31 was confirmed.

1H-NMR (CDCl3): δ 7.84 (1H, d), 7.32 (1H, d), 7.27 (1H, d), 6.33 (1H, d), 5.26 (1H, s), 1.52 (9H, s) , 1.41 (9H, s), 1.28 (9H, s)

Synthesis Example 1-2

(Synthesis of the exemplified compound 1-31) via a Heck reaction

After adding 80.0 g of 2,4-di-t-butylphenol to 240 ml of toluene, it was dissolved, cooled to 5 ° C, and 72.5 g of 48% HBr was added. Next, 37.9 g of 35% H ₂ O _{2 was} added dropwise, and after completion of the dropwise addition, the reaction was further carried out at room temperature for 4 hours. After the completion of the reaction, the aqueous layer was removed, washed with a NaHCO ₃ aqueous solution and a Na ₂ SO ₃ aqueous solution, and then washed with water, and then the toluene layer was separated and concentrated under reduced pressure to obtain a bromo-form crystal. Next, 110.0 g of bromo-form, 62.0 g of t-butyl acrylate, 82.0 g of sodium hydrogencarbonate, 7 mg of palladium(II) chloride, and tri-n-butyl were added to 330 ml of dimethylacetamide. 7.0 g of the amine was reacted at an internal temperature of 110 ° C for 3 hours. After the reaction, the undissolved residue such as sodium hydrogencarbonate was filtered, washed with ethyl acetate and a diluted aqueous solution of hydrochloric acid, and washed with water. The obtained crude crystals were recrystallized from a mixed solvent of methanol/water (7/1) to give white crystals of 85% yield. The obtained crystal was analyzed by 1H-NMR and MASS spectrum, and was confirmed to be an exemplified compound 1-31.

1H-NMR (CDCl3): δ 7.84 (1H, d), 7.32 (1H, d), 7.27 (1H, d), 6.33 (1H, d), 5.26 (1H, s), 1.52 (9H, s) , 1.41 (9H, s), 1.28 (9H, s)

Synthesis Example 2-1

(Synthesis of Compound 1-54)

After dissolving 91.0 g of 2,4-di-tert-pentylphenol in 240 ml of toluene, it was cooled to 5 ° C, and 72.5 g of 48% HBr was further added. Next, 37.9 g of 35% H ₂ O _{2 was} added dropwise, and after the completion of the dropwise addition, the reaction was further continued at room temperature for 4 hours. After the completion of the reaction, the aqueous layer was removed, washed with a NaHCO ₃ aqueous solution and a Na ₂ SO ₃ aqueous solution, and then washed with water, and then the toluene layer was separated and concentrated under reduced pressure to give crystals of the bromine. Next, 122.0 g of bromine, 62.0 g of t-butyl acrylate, 82.0 g of sodium hydrogencarbonate, 7 mg of palladium (II) chloride, and 7.0 g of tri-n-butylamine were added to 330 ml of dimethylacetamide. The reaction was carried out at 110 ° C for 3 hours. After the reaction, the undissolved residue such as sodium hydrogencarbonate was filtered, washed with ethyl acetate and a diluted aqueous solution of hydrochloric acid, and washed with water. The residue thus obtained was purified by column chromatography to give a transparent liquid of 80% yield. The obtained liquid was analyzed by 1H-NMR and MASS spectrum, and was confirmed to be an exemplified compound 1-54.

1H-NMR (CDCl3): δ 7.89 (1H, d), 7.23 (1H, d), 7.19 (1H, d), 6.34 (1H, d), 5.38 (1H, s), 1.85 (2H, q) , 1.60 (2H, q), 1.53 (9H, s), 1.38 (6H, s), 1.25 (6H, s), 0.66 (6H, t)

Synthesis Example 3-1

(Synthesis of Compound 1-55)

After dissolving 129.0 g of 2,4-di-α-cumenylphenol in 240 ml of toluene, it was cooled to 5 ° C, and 72.5 g of 48% HBr was added. Next, 37.9 g of 35% H ₂ O _{2 was} added dropwise, and after the completion of the dropwise addition, the reaction was continued at room temperature for 4 hours. After the completion of the reaction, the aqueous layer was removed, washed with aq. NaHCO ₃ and Na ₂ SO ₃ aqueous solution. After washing with water, the toluene layer was separated and concentrated under reduced pressure to give crystals of br Next, 160.0 g of bromine, 62.0 g of t-butyl acrylate, 82.0 g of sodium hydrogencarbonate, 7 mg of palladium (II) chloride, and 7.0 g of tri-n-butylamine were added to 330 ml of dimethylacetamide. The reaction was carried out at an internal temperature of 110 ° C for 3 hours. After the reaction, the undissolved residue such as sodium hydrogencarbonate was filtered, washed with ethyl acetate and a dilute aqueous hydrochloric acid solution, and washed with water, and then the organic layer was separated and concentrated. The obtained residue was purified by column chromatography to give a transparent liquid of 82% yield. The obtained liquid was analyzed by 1H-NMR and MASS spectrum, and was confirmed to be an exemplified compound 1-55.

1H-NMR (CDCl3): δ 7.75 (1H, d), 7.37 to 7.25 (12H, m), 6.28 (1H, d), 4.62 (1H, s), 1.72 (6H, s), 1.58 (6H, s), 1.46 (9H, s)

Synthesis Example 4-1 (Synthesis of Compound 1-62)

After 86.0 g of 4,6-di-tert-butyl-m-cresol was added to 240 ml of toluene and dissolved, it was cooled to 5 ° C, and 72.5 g of 48% HBr was further added. Next, 37.9 g of 35% H ₂ O _{2 was} added dropwise, and after the completion of the dropwise addition, the reaction was continued at room temperature for 4 hours. After the completion of the reaction, the aqueous layer was removed, and washed with a NaHCO ₃ aqueous solution and a Na ₂ SO ₃ aqueous solution. After washing with water, the toluene layer was separated and concentrated under reduced pressure to give a bromo-form of yield of 90%. Crystallization. Next, bromine-form 117.0 g, t-butyl acrylate 62.0 g, sodium hydrogencarbonate 82.0 g, palladium (II) chloride 7 mg, and tri-n-butyl group were added to 330 ml of dimethylacetamide. 7.0 g of an amine was reacted at an internal temperature of 110 ° C for 3 hours. After the reaction, the undissolved residue such as sodium hydrogencarbonate was filtered, washed with ethyl acetate and a diluted aqueous solution of hydrochloric acid, and washed with water. The obtained crude crystals were recrystallized from a mixed solvent of methanol/water (7/1) to give white crystals (yield: 81%). The obtained crystal was analyzed by 1H-NMR and MASS spectrum, and was confirmed to be an exemplified compound 1-62.

1H-NMR (CDCl3): δ 8.07 (1H, d), 7.60 (1H, s), 6.40 (1H, d), 5.28 (1H, s), 2.65 (3H, s), 1.52 (9H, s), 1.39(9H,s), 1.26(9H,s)

Synthesis Example 5-1 (Synthesis of the compound 1-70)

After adding 80.0 g of 4-tert-octylphenol to 240 ml of toluene and dissolving, it was cooled to 5 ° C, and 72.5 g of 48% HBr was further added. Next, 37.9 g of 35% H ₂ O _{2 was} added dropwise, and after the completion of the dropwise addition, the reaction was continued at room temperature for 4 hours. After the completion of the reaction, the aqueous layer was removed, washed with aq. NaHCO ₃ and Na ₂ SO ₃ aqueous solution, and then washed with water, and then the toluene layer was separated and concentrated under reduced pressure to give a bromo-form of yield of 90%. Crystallization. Next, 110.0 g of bromo-form, 56.0 g of t-butyl acrylate, 74.0 g of sodium hydrogencarbonate, 6 mg of palladium chloride (1I), and tri-n-butyl were added to 330 ml of dimethylacetamide. The amine was 6.3 g, and the reaction was carried out at an internal temperature of 110 ° C for 3 hours. After the reaction, the undissolved residue such as sodium hydrogencarbonate was filtered, washed with ethyl acetate and a diluted aqueous solution of hydrochloric acid, and washed with water. The obtained crude crystals were recrystallized from a mixed solvent of methanol/water (7/1) to give 82% white crystals. The obtained crystal was analyzed by 1H-NMR and MASS spectrum, and was confirmed to be the exemplified compound 1-71.

1H-NMR (CDCl3): δ 7.84 (1H, d), 7.41 to 7.19 (3H, m), 5.41 (1H, s), 1.67 (2H, s), 1.54 (9H, s), 1.32 (6H, s), 0.69 (9H, s)

Synthesis Example 6-1

(Synthesis of Compound 1-71)

After 83.0 g of p-cumenylphenol was added to 240 ml of toluene and dissolved, the mixture was cooled to 5 ° C, and 72.5 g of 48% HBr was added. Next, 37.9 g of 35% H ₂ O _{2 was} added dropwise, and after the completion of the dropwise addition, the reaction was continued at room temperature for 4 hours. After the completion of the reaction, the aqueous layer was removed, washed with a NaHCO ₃ aqueous solution and a Na ₂ SO ₃ aqueous solution, and then washed with water, and then the toluene layer was separated and concentrated under reduced pressure to give a bromo-form of 90% yield. Crystallization. Next, 100.0 g of bromo-form, 56.0 g of t-butyl acrylate, 74.0 g of sodium hydrogencarbonate, 6 mg of palladium(II) chloride, and tri-n-butyl were added to 330 ml of dimethylacetamide. The amine was 6.3 g, and the reaction was carried out for 3 hours at an internal temperature of 110 °C. After the reaction, the undissolved residue such as sodium hydrogencarbonate was filtered, washed with ethyl acetate and a diluted aqueous solution of hydrochloric acid, and washed with water. The obtained crude crystals were recrystallized from a mixed solvent of methanol/water (8/1) to give white crystals of 83% yield. The obtained crystal was analyzed by 1H-NMR and MASS spectrum, and was confirmed to be the exemplified compound 1-71.

1H-NMR (CDCl3): δ 7.93 (1H, d), 7.38 to 6.75 (8H, m), 6.71 (1H, s), 6.55 (1H, d), 1.68 (6H, s), 1.56 (9H, s)

In the present invention, the amount of the compound represented by the above formula (1) is appropriately selected insofar as the object of the present invention is not impaired, but it is usually 0.001 to 2.0 parts by mass based on 100 parts by mass of the cellulose ester. It is preferably 0.01 to 1.0 part by mass, more preferably 0.05 to 0.5 part by mass. Two or more of them may be used in combination.

Further, impurities (for example, raw materials and by-products) accompanying the production may be contained. Examples of the by-products include the following compounds of the general formula (3).

(wherein R ¹ represents a substituent, and n represents an integer of 0 to 4. The plural R ¹ may be the same or different).

The substituent of the general formula (3) has the same meaning as R ^{1 of the} above general formula (1).

Optical Film

Next, the optical film of the present invention will be described in detail.

In the present invention, the optical film is a functional film used in various display devices such as a liquid crystal display, a plasma display, and an organic EL display, and is specifically a polarizing plate protective film, a retardation film, an antireflection film, and a brightness for a liquid crystal display device. An optical compensation film such as a film, a hard coat film, an anti-glare film, an antistatic film, and an enlarged viewing angle is provided.

The resin used for the resin film of the base material of the optical film of the present invention may be a polycarbonate resin, a polystyrene resin, or a polyether, in addition to the cellulose ester resin alone or the cellulose ester resin. Lanthanide resin, polyester resin, polyallyl resin, acrylic resin (including copolymer), olefin resin (original spinylene resin, cyclic olefin resin, cyclic conjugated diene resin) A resin such as a vinyl alicyclic hydrocarbon resin or a cellulose ether resin or a vinyl resin (including a polyvinyl acetate resin or a polyvinyl alcohol resin). Among them, a cellulose ester-based resin alone or a combination of a cellulose ester-based resin and an acrylic resin is preferable, and a cellulose ester-based resin is also preferable.

The resin content other than the cellulose ester-based resin is preferably 0.1 to 70% by mass, and preferably 1 to 30% by mass.

The optical film of the present invention can be suitably used for a polarizing plate protective film (including a polarizing plate protective film imparting a functional layer) and a retardation film.

"Cellulose Ester"

Next, an optical film (hereinafter simply referred to as a cellulose ester film) containing the cellulose ester and the cellulose ester of the present invention will be described in detail.

The cellulose ester film used in the present invention can be produced by a solution casting method or a melt casting method. The solution casting method is a solution in which a cellulose ester is dissolved in a solvent (blend) is cast on a support, and a solvent is evaporated to form a film. The melt casting method forms a film by casting a cellulose ester by heating to melt on a support. Since the melt casting method can greatly reduce the amount of the organic solvent used in the production of the film, a film having a greatly improved environmental suitability can be obtained as compared with the conventional solution casting method using a large amount of an organic solvent, so that the melt flow is used in the present invention. It is preferred to form a cellulose ester film by a method.

The melt casting in the present invention is a method in which a cellulose ester is heated and melted without using a solvent to a temperature at which fluidity is exhibited, and a film is formed by using the method, for example, a liquid cellulose ester is extruded from a mold to form a film. Methods. Further, a solvent can be used in a part of the process of preparing the molten cellulose ester, but in the melt film forming process which is formed into a film form, the forming process can be carried out without using a solvent.

The cellulose ester constituting the optical film is not particularly limited as long as it can be melt-formed, and for example, an aromatic carboxylic acid ester or the like can be used. However, in view of obtaining film properties such as optical characteristics, it is used. The lower fatty acid ester of cellulose is preferred. The lower fatty acid in the cellulose lower fatty acid ester in the present invention means a fatty acid having 5 or less carbon atoms, and examples thereof include cellulose acetate, cellulose propionate, cellulose butyrate, and cellulose III. A lower fatty acid ester of cellulose such as methyl acetate or the like is preferred. In the cellulose ester substituted with a fatty acid having 6 or more carbon atoms, the melt film formability is good, but the obtained cellulose ester film has low mechanical properties and is difficult to use as a substantially optical film. In order to combine both mechanical properties and melt film forming properties, a mixed fatty acid ester such as cellulose acetate propionate or cellulose acetate butyrate may be used. Further, triacetyl cellulose, which is a cellulose ester generally used in solution casting film formation, is a cellulose ester having a melting temperature higher than a decomposition temperature, and thus it is difficult to use it on a melt film.

Among the above cellulose esters, cellulose acetate propionate and cellulose acetate butyrate are also preferably used.

Next, the degree of substitution of the thiol group of the cellulose ester used in the present invention will be described.

In the cellulose, the second, third, and sixth positions of one glucose unit each have one total of three hydroxyl groups, and the total degree of substitution is a value shown by combining a plurality of sulfhydryl groups on an average of 1 glucose unit. Therefore, the maximum degree of substitution is 3.0. These thiol groups may be substituted on the 2nd, 3rd, and 6th positions of the glucose unit, or may be substituted.

As a substitution degree of the mixed fatty acid ester, more preferably, the lower fatty acid ester of cellulose acetate propionate or cellulose acetate butyrate is a fluorenyl group having 2 to 4 carbon atoms as a substituent, and The degree of substitution of the fluorenyl group is X, and when the degree of substitution of the fluorenyl group or the butyl group is Y, the cellulose ester which can satisfy the cellulose esters of the following formulas (I), (II) and (III) is contained. Further, the degree of substitution of the thiol group with the degree of substitution of other thiol groups is determined by the method specified in ASTM-D817-96.

Formula (I) 2.4≦X+Y≦2.9

Formula (II) 0≦X≦2.4

Formula (III) 0.5≦Y≦2.9

Among them, cellulose acetate propionate is particularly preferred, and 1.2 ≦ X ≦ 2.1, 0.6 ≦ Y ≦ 1.4 is preferred. The cellulose ester having a different degree of substitution of the fluorenyl group may be in the above range as the cellulose ester film as a whole. The portion which is not substituted with the above mercapto group is generally present as a hydroxyl group. These can be synthesized by a known method.

The cellulose ester used in the present invention is preferably a number average molecular weight (Mn) of 50,000 to 150,000, more preferably an average molecular weight of 55,000 to 120,000, and most preferably an average molecular weight of 60,000 to 100,000.

Further, the cellulose ester used in the present invention is preferably a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of from 1.3 to 5.5, particularly preferably from 1.5 to 5.0, more preferably from 1.7 to 4.0, more preferably. It is preferably a cellulose ester of 2.0 to 3.5.

Further, Mn and Mw/Mn can be calculated by gel permeation chromatography from the following method.

The measurement conditions are as follows.

Solvent: tetrahydrofuran

Device: HLC-8220 (Tosoh system)

Column: TSKgel SuperHM-M (made by Tosoh)

Column temperature: 40 ° C

Sample concentration: 0.1% by mass

Injection volume: 10μl

Flow rate: 0.6ml/min

Proofreading curve: using standard polystyrene: PS-1 (Polymer)

Laboratories Inc.) Mw=2,560,000-580 9 samples

Proofreading curve.

The raw material cellulose of the cellulose ester used in the present invention may be wood pulp or cotton velvet, and the wood pulp may be conifer or broad-leaved tree, but a conifer is preferred. From the viewpoint of the peeling property at the time of film formation, it is preferable to use cotton velvet. These obtained cellulose esters may be suitably mixed or used alone.

For example, cellulose acetate can be used: cellulose ester from wood pulp (conifer): the ratio of cellulose ester from wood pulp (broadleaf) is 100:0:0, 90:10:0, 85:15 :0, 50:50:0, 20:80:0, 10:90:0, 0:100:0, 0:0:100, 80:10:10, 85:0:15, 40:30:30 .

The cellulose ester is obtained, for example, by substituting an ethyl acetate, a propanol anhydride, and/or a butyl group in the above range by using acetic anhydride, propionic anhydride, and/or butyric anhydride according to a usual method. The method for synthesizing the cellulose ester is not particularly limited. For example, it can be synthesized by the method described in JP-A-10-45804 or JP-A-6-501040.

The content of the alkaline earth metal of the cellulose ester used in the present invention is preferably in the range of 1 to 50 ppm. When the amount exceeds 50 ppm, the adhesion of the lip to the die may increase or the slitting portion may be broken when the heat is extended or after the heat extension. It is also easy to break when it is less than 1 ppm, and the reason is not clear. When the amount is less than 1 ppm, the burden of the washing step is too large or too bad. It is preferably in the range of 1 to 30 ppm. The alkaline earth metal is a total content of Ca and Mg, and can be measured by an X-ray photoelectron spectroscopy analyzer (XPS).

The content of residual sulfuric acid in the cellulose ester used in the present invention is preferably in the range of 0.1 to 45 ppm in terms of sulfur element. It can be assumed that they are contained in the form of salt. When the residual sulfuric acid content exceeds 45 ppm, the lip portion deposit during heat fusion may increase. Further, it is not preferable because it is easily broken at the time of heat stretching or slitting after heat stretching. Less preferred, but when it is less than 0.1, not only the burden of the washing step of the cellulose ester is too large, but it is not easy to break. This may affect the resin for an increase in the number of washes but it is not entirely clear. It is preferably in the range of 1 to 30 ppm. The residual sulfuric acid content can be determined by the method specified in ASTM-D817-96.

The content of the free acid in the cellulose ester used in the present invention is preferably from 1 to 500 ppm. When it exceeds 500 ppm, the deposit of the lip part will increase and it will break easily. When it exceeds 500 ppm, the deposit of the lip part will increase and it will break easily. It is difficult to wash up to 1ppm. And the range of 1 to 100 ppm is preferable, and it is more difficult to break. It is particularly preferably in the range of 1 to 70 ppm. The free acid content can be determined by the method specified in ASTM-D817-96.

When the synthetic cellulose ester is washed and compared with the case of using the solution casting method, the residual acid content can be made into the above range by further sufficiently performing, and when the film is produced by the melt casting method, A film having a reduced adhesion to the lip portion (1ip) and excellent planarity was obtained, and a film having dimensional change, mechanical strength, transparency, moisture permeability, Rt value, and Ro value was obtained. Further, the cellulose ester may be washed, and in addition to water, a weak solvent such as methanol or ethanol, or a mixed solvent of a weak solvent and a good solvent which is a weak solvent may be used, and an inorganic substance other than the residual acid may be removed. Low molecular organic impurities. Further, the washing of the cellulose ester can be carried out in the presence of an antioxidant such as a hindered amine or a phosphite, and the heat resistance of the cellulose ester and the film stability can be improved.

Further, in order to improve the heat resistance, mechanical properties, optical properties, and the like of the cellulose ester, it is dissolved in a good solvent of the cellulose ester, and then precipitated in a weak solvent to remove low molecular weight components and other impurities of the cellulose ester. In this case, it is preferable to carry out the treatment in the presence of an antioxidant similarly to the washing of the cellulose ester.

Further, after the reprecipitation treatment of the cellulose ester, other polymers or low molecular compounds may be added.

Moreover, it is preferable that the cellulose ester used in the present invention has a small amount of foreign matter as a film. The bright spot foreign matter is such that two polarizing plates are arranged in a straight line (orthogonal Nicol), and a cellulose ester film is disposed therebetween, and one side is irradiated with a light source, and when the cellulose ester film is observed from the other side, the light of the light source is seen. The point of leakage. In this case, it is preferable that the polarizing plate used for the evaluation is a protective film having no bright foreign matter, and it is preferable to use a glass plate for the protection of the polarizer. One of the reasons for highlighting foreign matter can be considered to be caused by cellulose which is not vinegarized or low in acetification of cellulose ester, and cellulose ester with less foreign matter is used (the cellulose ester with less dispersion degree of substitution is used). In at least one of the process of filtering the molten cellulose ester or the cellulose ester, or the process of obtaining a precipitate, the film can be once in a solution state and the bright spot foreign matter is removed through the filtration step. The molten resin is more efficient because of its higher viscosity.

The thinner the film thickness, the smaller the number of bright spots per unit area, and the smaller the content of the cellulose ester contained in the film, the less the bright foreign matter tends to be, but the bright spot foreign matter has a bright spot diameter of 0.01 mm or more and 200 pieces. It is preferable that it is less than /cm ² , preferably 100 pieces/cm ² or less, more preferably 50 pieces/cm ² or less, particularly preferably 30 pieces/cm ² or less, and 10 pieces/cm ² or less. Good, nothing is best. Further, the bright spot of 0.005 to 0.01 mm or less is preferably 200 pieces/cm ² or less, preferably 100 pieces/cm ² or less, more preferably 50 pieces/cm ² or less, and 30 pieces/cm ² or less. It is especially good, and 10/cm ² or less is excellent, and none is the best.

When the bright foreign matter is removed by melt filtration, the cellulose ester composition after mixing with a plasticizer, a deterioration inhibitor, an antioxidant, or the like is filtered, and the foreign matter is brightened. The removal efficiency is higher and better. Of course, in the synthesis of cellulose ester, it can be reduced by filtration after being dissolved in a solvent. It is also possible to filter by appropriately mixing the ultraviolet absorber or other additives. The filtration is preferably carried out under the filtration of a cellulose ester-containing melt having a viscosity of 10,000 Pa·s or less, preferably 5,000 Pa·s or less, more preferably 1000 Pa·s or less, and particularly preferably 500 Pa·s or less. As the filter medium, a fluororesin such as glass silicate, cellulose oxime, filter paper, or tetrafluoroethylene resin can be preferably used, and ceramics, metals, and the like are particularly preferable. The absolute filtration accuracy is preferably 50 μm or less, preferably 30 μm or less, more preferably 10 μm or less, and most preferably 5 μm or less. These can be used in combination as appropriate. The filter medium may be of a surface filtration type or a depth filtration type, and the volume filtration type is preferred because it is not blocked.

In other embodiments, the cellulose ester of the raw material may be dissolved in a solvent at least once, and the dried cellulose ester may be used. At this time, the dried cellulose ester is dissolved in a solvent together with at least one type of plasticizer, ultraviolet absorber, deterioration inhibitor, antioxidant, and matting agent. As the solvent, dichloromethane, methyl acetate, and dioxolane can be used as a good solvent for the solution casting method, and a weak solvent such as methanol, ethanol or butanol can be used. It can be cooled to -20 ° C or lower, or heated to 80 ° C or higher during the dissolution process. When such a cellulose ester is used, it is easy to uniformly mix the respective additives in a molten state, and the optical characteristics can be made uniform.

The optical film of the present invention may be a polymer component other than a cellulose ester. The polymer component to be mixed is preferably one having a good compatibility with a cellulose ester, and the transmittance in the case of a film is 80% or more, preferably 90% or more, and more preferably 92% or more.

"Antioxidants"

The resin which becomes the base material of the optical film of the present invention not only promotes decomposition by oxygen but also by oxygen, and therefore it is preferable for the optical film of the present invention to contain an antioxidant as a stabilizer.

In particular, in a high-temperature environment in which a melt film is formed, since it is accelerated by the heat of the film forming material and oxygen, it is preferable to contain an antioxidant.

Further, in the cellulose ester of the preferred embodiment of the present invention, it is also preferred to carry out washing in the presence of an antioxidant in the case of suspension washing with a weak solvent. The antioxidant to be used may be a compound which can inactivate the radical generated by the cellulose ester or inhibit the deterioration of the cellulose ester caused by the addition of oxygen to the radical generated by the cellulose ester. There is no particular limitation.

The antioxidant used in the suspension washing of the cellulose ester may also remain in the cellulose ester after washing. The residual amount is preferably from 0.01 to 2,000 ppm, more preferably from 0.05 to 1,000 ppm, still more preferably from 0.1 to 100 ppm.

The antioxidant which is useful in the present invention is not particularly limited as long as it can suppress deterioration of the film forming material by oxygen, and examples of useful antioxidants include phenolic compounds, hindered amine compounds, and phosphorus. A compound, a sulfur-based compound, a lactone-based compound, an acrylate-based compound, an oxygen scavenger, and the like are preferable, and among them, a hindered phenol-based compound, a phosphorus-based compound, a lactone-based compound, and an acrylate-based compound are particularly preferable. By adding these compounds, transparency, heat resistance, and the like are not lowered, and coloring or strength reduction of the molded body due to heat or thermal oxidative degradation or the like can be prevented. These antioxidants can be used individually or in combination of 2 or more types.

(phenolic compound)

As one of the useful antioxidants used in the present invention, a phenol compound is preferred.

The phenolic compound is a known compound, and is contained in the 2,6-dialkylphenol derivative compound, for example, as described in the columns 12 to 14 of the specification of U.S. Patent No. 4,839,405. As a preferred compound among such compounds, a compound represented by the following general formula (A) is preferred.

In the formula, R ₁₁ to R ₁₆ represent a hydrogen atom or a substituent. The substituent may, for example, be a halogen atom (for example, a fluorine atom or a chlorine atom) or an alkyl group (for example, a methyl group, an ethyl group, an isopropyl group, a hydroxyethyl group, a methoxymethyl group, a trifluoromethyl group or a t-butyl group). a group such as a cycloalkyl group (e.g., cyclopentyl, cyclohexyl, etc.), an aralkyl group (e.g., benzyl, 2-phenylethyl, etc.), an aryl group (e.g., phenyl, naphthyl, p-tolyl, P-chlorophenyl, etc.), alkoxy (eg methoxy, ethoxy, isopropoxy, butoxy, etc.), aryloxy (eg phenoxy, etc.), cyano, guanamine ( For example, an acetamino group, a propylamino group, etc., an alkylthio group (for example, a methylthio group, an ethylthio group, a butylthio group, etc.), an arylthio group (for example, a phenylthio group, etc.), Sulfonamide (eg, methanesulfonamide, benzenesulfonylamino, etc.), urea group (eg, 3-methylureido, 3,3-dimethylureido, 1,3-dimethylureido) Etc.), sulfonamide (dimethylamine sulfonamide, etc.), aminomethyl thiol (eg, methylaminomethyl thiol, ethylaminomethyl decyl, dimethylaminomethyl hydrazino, etc.) Aminesulfonyl (e.g., ethylamine sulfonyl, dimethylamine sulfonyl, etc.), alkoxycarbonyl (e.g., methoxycarbonyl, ethoxycarbonyl) An aryloxycarbonyl group (e.g., phenoxycarbonyl group, etc.), a sulfonyl group (e.g., a sulfonyl group, a butyl sulfonyl group, a phenyl sulfonyl group, etc.), a fluorenyl group (e.g., an ethyl fluorenyl group, a propyl group) Anthracenyl, butyl hydrazide, etc., an amine group (methylamino group, ethylamino group, dimethylamino group, etc.), a cyano group, a hydroxyl group, a nitro group, a nitroso group, an amine oxide group (for example, a pyridine-oxide group), An imido group (for example, an oximine group or the like), a disulfide group (for example, a benzene disulfide group, a benzothiazolyl-2-disulfide group, etc.), a carboxyl group, a sulfo group, or a heterocyclic group (for example, Pyrrolyl, pyrrolidinyl, pyrazolyl, imidazolyl, pyridyl, benzimidazolyl, benzothiazolyl, benzoxazolyl, etc.). These substituents may be further substituted.

Further, a phenol compound wherein R ₁₁ is a hydrogen atom and R ₁₂ and R ₁₆ are a t-butyl group is preferred. Specific examples of the phenolic compound may include n-octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate, n-octadecyl 3-( 3,5-di-t-butyl-4-hydroxyphenyl)-acetate, n-octadecyl 3,5-di-t-butyl-4-hydroxybenzoate, n-hexyl 3,5-di-t-butyl-4-hydroxyphenyl benzoate, n-lauryl 3,5-di-t-butyl-4-hydroxyphenyl benzoate, neo-lauryl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, lauryl β(3,5-di-t-butyl-4-hydroxyphenyl)propionate, B Α-(4-hydroxy-3,5-di-t-butylphenyl)isobutyrate, octadecyl α-(4-hydroxy-3,5-di-t-butylphenyl) Isobutyrate, octadecyl α-(4-hydroxy-3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2-(n-octylthio)ethyl 3, 5-di-t-butyl-4-hydroxy-benzoate, 2-(n-octylthio)ethyl 3,5-di-t-butyl-4-hydroxy-phenyl acetate, 2-(n-octadecylthio)ethyl 3,5-di-t-butyl-4-hydroxyphenyl acetate, 2-(n-octadecylthio)ethyl 3, 5-di-t-butyl-4-hydroxy-benzoate, 2-(2-hydroxyethylthio)ethyl 3,5-di-t-butyl-4-hydroxybenzoate, Diethyl glycol bis-( 3,5-di-t-butyl-4-hydroxy-phenyl)propionate, 2-(n-octadecylthio)ethyl 3-(3,5-di-t-butyl- 4-hydroxyphenyl)propionate, stearylamine N,N-bis-[extended ethyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], n -butylimine N,N-bis-[stretch ethyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2-(2-stearyloxyloxy) Ethylthio)ethyl 3,5-di-t-butyl-4-hydroxybenzoate, 2-(2-stearyloxyethylthio)ethyl 7-(3-methyl -5-t-butyl-4-hydroxyphenyl)heptanoate, 1,2-propanediol bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] , ethylene glycol bis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], neopentyl glycol bis-[3-(3,5-di-t- Butyl-4-hydroxyphenyl)propionate], ethylene glycol bis-(3,5-di-t-butyl-4-hydroxyphenyl acetate), glycerol-1-n-octadecane Acid ester-2,3-bis-(3,5-di-t-butyl-4-hydroxyphenyl acetate), pentaerythritol bismuth-[3-(3',5'-di-t-butyl -4'-hydroxyphenyl)propionate], 3,9-bis-{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanyloxy] -1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,1,1-trimethylolethane- -[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], sorbitol hexa-[3-(3,5-di-t-butyl-4-hydroxyl) Phenyl)propionate], 2-hydroxyethyl 7-(3-methyl-5-t-butyl-4-hydroxyphenyl)propionate, 2-stearyloxyethyl 7-(3 -Methyl-5-t-butyl-4-hydroxyphenyl)heptanoate, 1,6-n-hexanediol-bis[(3',5'-di-t-butyl-4-hydroxyl) Phenyl)propionate], pentaerythritol oxime (3,5-di-t-butyl-4-hydroxyhydrocinnamate). For the phenol compound of the above form, for example, "Irganox 1076" and "Irganox 1010" available from Ciba Japan Co., Ltd. can be used.

(hindered amine compound)

As one of the useful antioxidants in the present invention, a hindered amine compound represented by the following general formula (B) is preferred.

In the formula, R ₂₁ to R ₂₇ represent a substituent. The substituent is synonymous with the substituent represented by R ₁₁ to R _{15 of the} above general formula (A). R ₂₄ is preferably a hydrogen atom or a methyl group, R ₂₇ is preferably a hydrogen atom, and R ₂₂ , R ₂₃ , R ₂₅ and R ₂₆ are preferably a methyl group.

Specific examples of the hindered amine compound include bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacic acid and bis(2,2,6,6-tetramethyl-4). - piperidine) succinate, bis(1,2,2,6,6-pentamethyl-4-piperidine) sebacic acid, bis(N-octyloxy-2,2,6,6-tetramethyl Alkyl-4-piperidine) sebacic acid, bis(N-benzyloxy-2,2,6,6-tetramethyl-4-piperidine)sebacic acid, bis(N-cyclohexyloxy) -2,2,6,6-tetramethyl-4-piperidine) sebacic acid, bis(1,2,2,6,6-pentamethyl-4-piperidine)2-(3,5- Di-t-butyl-4-hydroxybenzyl)-2-butylmalonate, bis(1-propenyl 2,2,6,6-tetramethyl-4-piperidine) 2 ,2-bis(3,5-di-t-butyl-4-hydroxybenzyl)-2-butylmalonate, bis(1,2,2,6,6-pentamethyl-4 - piperidine) sebacate, 2,2,6,6-tetramethyl-4-piperidine methacrylate, 4-[3-(3,5-di-t-butyl-4-hydroxyl) Phenyl)propanyloxy]-1-[2-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propanyloxy)ethyl]-2,2, 6,6-Tetramethylpiperidine, 2-methyl-2-(2,2,6,6-tetramethyl-4-piperidine)amino-N-(2,2,6,6-tetra Methyl-4-piperidine)propanamine, hydrazine (2,2,6,6-tetramethyl-4-piperidine) 1,2,3,4-butane tetracarboxylate, hydrazine (1, 2,2,6,6-pentamethyl-4-piperidine) 1,2,3,4-butyl Alkanetetracarboxylic acid ester and the like.

Further, it may be a compound in a polymer form, and specific examples thereof include N,N',N",N"'-肆-[4,6-bis-[butyl-(N-methyl-2, 2,6,6-Tetramethylpiperidin-4-yl)amino]-triazin-2-yl]-4,7-diazadecane-1,10-diamine, dibutylamine and 1,3,5-triazine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidine)-1,6-hexamethyldiamine and N-(2, Polycondensate of 2,6,6-tetramethyl-4-piperidine)butylamine, dibutylamine and 1,3,5-triazine with N,N'-bis(2,2,6, Polycondensate of 6-tetramethyl-4-piperidine)butylamine, poly[{(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2 ,4-diyl}{(2,2,6,6-tetramethyl-4-piperidine)imide}hexamethyl{(2,2,6,6-tetramethyl-4-piperidine) Imine}], 1,6-hexanediamine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidine) and morpholine-2,4,6-trichloro -1,3,5-triazine polycondensate, poly[(6-morpholino-s-triazine-2,4-diyl)[(2,2,6,6,-tetramethyl- 4-piperidinium imine]-hexamethyl-[[2,2,6,6-tetramethyl-4-piperidine)imine]] piperidine ring is a complex combination of a triazine skeleton High molecular weight HALS; polymer of dimethyl succinate with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 1,2,3,4-butanetetracarboxylic acid and 1 ,2 , 2,6,6-pentamethyl-4-piperidinol and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxan [ 5,5] a compound such as a mixed esterified product of undecane, such as a compound in which a piperidine ring is bonded via an ester bond, but is not limited thereto.

They also use polycondensates of dibutylamine and 1,3,5-triazine with N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)butylamine. , poly[{(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl) 4-piperidine)imine}hexamethyl{(2,2,6,6-tetramethyl-4-piperidine)imine}], dimethyl succinate and 4-hydroxy-2, The polymer of 2,6,6-tetramethyl-1-piperidineethanol or the like preferably has a number average molecular weight (Mn) of 2,000 to 5,000.

The hindered amine compound of the above-mentioned form is, for example, "Tinuvin 144" and "Tinuvin 770" available from Ciba Japan Co., Ltd., and the trade name "ADK STAB LA-52" available from the company ADEKA.

(phosphorus compound)

As one of the useful antioxidants in the present invention, a phosphorus system selected from the group consisting of phosphite, phosphonite, phosphinite, or phosphane The compound is preferably a compound having a partial structure represented by the following general formulas (C-1), (C-2), (C-3), (C-4), or (C-5) in the molecule. .

In the formula, Ph ₁ and Ph' ₁ represent a substituent. The substituent is synonymous with the substituent represented by R ₁₁ to R ₁₅ in the above general formula (A). Preferably, Ph ₁ and Ph' ₁ represent a phenyl group, and the hydrogen atom of the phenyl group may be a phenyl group, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or a carbon number of 6 to 12; An alkylcycloalkyl group or an aralkyl group having 7 to 12 carbon atoms is substituted. Ph ₁ and Ph' ₁ may be identical or different from each other. X represents a single bond, a sulfur atom or a -CHR ₆ - group. R ₆ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 5 to 8 carbon atoms. Further, it may be substituted with a substituent which is synonymous with the substituent represented by R ₁₁ to R _{15 of the} above general formula (A).

In the formula, Ph ₂ and Ph' ₂ represent a substituent. The substituent is synonymous with the substituent represented by R ₁₁ to R ₁₅ in the above general formula (A). Preferably, Ph ₂ and Ph' ₂ represent a phenyl group or a biphenyl group, and the hydrogen atom of the phenyl group or biphenyl group may be an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or a carbon number of 6 Substituted by an alkylcycloalkyl group of ～12 or an aralkyl group having 7 to 12 carbon atoms. Ph ₂ and Ph' ₂ may be identical or different from each other. Further, it may be substituted with a substituent which is synonymous with the substituent represented by R ₁₁ to R _{15 of the} above general formula (A).

In the formula, Ph ₃ represents a substituent. The substituent is synonymous with the substituent represented by R ₁₁ to R ₁₅ in the above general formula (A). Preferably, Ph ₃ represents a phenyl group or a biphenyl group, and the hydrogen atom of the phenyl group or biphenyl group may be an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an alkyl group having 6 to 12 carbon atoms. Substituted by a cycloalkyl group or an aralkyl group having 7 to 12 carbon atoms. Further, it may be substituted with a substituent which is synonymous with the substituent represented by R ₁₁ to R _{15 of the} above general formula (A).

In the formula, Ph ₄ represents a substituent. The substituent is synonymous with the substituent represented by R ₁₁ to R ₁₅ in the above general formula (A). P ₄ is preferably an alkyl group having 1 to 20 carbon atoms or a phenyl group which may be substituted with a substituent having the same meaning as the substituent represented by R ₁₁ to R _{15 of the} above general formula (A).

In the formula, Ph ₅ , Ph' ₅ and Ph" ₅ represent a substituent. The substituent is synonymous with the substituent represented by R ₁₁ to R _{15 of the} above general formula (A). Preferably, Ph ₅ , Ph' ₅ and Ph " ₅ " represents an alkyl group having 1 to 20 carbon atoms or a phenyl group which may be substituted with a substituent having the same meaning as the substituent represented by R ₁₁ to R _{15 of the} above general formula (A).

Specific examples of the phosphorus-based compound include triphenylphosphite, diphenylisodecylphosphite, phenyldiisodecylphosphite, hexamethylenephenylphosphite, and ginseng. (didecylphenyl) phosphite, ginseng (2,4-di-t-butylphenyl) phosphite, 10-(3,5-di-t-butyl-4-hydroxybenzyl) )-9,10-dihydro-9-oxo-10-phosphinophen-10-oxide, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy a monophosphite compound such as -2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepine or tridecyl phosphite; 4'-butylidene-bis(3-methyl-6-t-butylphenyl-di-tridecyl phosphite), 4,4'-isopropylidene-bis(phenyl-di- a diphosphite compound such as an alkyl (C12-C15) phosphite; triphenylphosphinate, bismuth (2,4-di-tert-butylphenyl) [1,1-biphenyl ]-4,4'-diylbisphosphonite, bismuth(2,4-di-tert-butyl-5-methylphenyl)[1,1-biphenyl]-4,4'- a phosphonite compound such as a dibasic bisphosphonite; a hypophosphorous compound such as a triphenylphosphite or a 2,6-dimethylphenyldiphenylphosphite; a triphenylphosphine or a ginseng a phosphine-based compound such as (2,6-dimethoxyphenyl)phosphine;

The phosphorus-based compound of the above form, for example, "Sumilizer GP" available from Sumitomo Chemical Co., Ltd., ADK STAB PEP-24G", "ADK STAB PEP-36" and "ADK STAB 3010" available from ADEKA Co., Ltd. "IRGAFOS P-EPQ", which is commercially available from Ciba Japan Co., Ltd., and "GSY-P101", which is commercially available from Dai Chemical Industry Co., Ltd.

(sulfur compound)

As one of the useful antioxidants in the present invention, a sulfur-based compound represented by the following general formula (D) is preferred.

In the formula, R ₃₁ and R ₃₂ represent a substituent. The substituent is synonymous with the substituent represented by R ₁₁ to R ₁₅ in the above general formula (A).

Specific examples of the sulfur-based compound include dilauryl 3,3-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3-sulfan Propionate, lauryl stearyl 3,3-thiodipropionate, pentaerythritol-indole (β-lauryl-thio-propionate), 3,9-bis(2-laurylthioethyl) -2,4,8,10-tetraoxaspiro[5,5]undecane, etc.

The sulfur-based compound of the above form is, for example, the trade name "Sumilizer TPL-R" and "Sumilizer TP-D" available from Sumitomo Chemical Co., Ltd.

(acrylate compound)

As one of the useful antioxidants in the present invention, an acrylate-based compound is preferred.

Specific examples of the acrylate-based compound include 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate. An acrylate-based compound such as 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate. The acrylate-based compound of the above-mentioned form is, for example, a trade name of "Sumilizer GM" and "Sumilizer GS" available from Sumitomo Chemical Co., Ltd.

(lactone compound)

As one of the useful antioxidants in the present invention, a lactone-based compound is preferred.

Specific examples of the lactone-based compound include 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-t-butylbenzofuran-2-one, 5,7. -Di-tert-butyl-3-[4-(2-stearyloxyethoxy)phenyl]benzofuran-2-one, 3,3'-bis[5,7-di-3rd 3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one], 5,7-di-t-butyl-3-(4-methoxyphenyl)benzo Furan-2-one, 5,7-di-t-butyl-3-phenylbenzofuran-2-one, 5,7-di-t-butyl-4-methyl-3-phenylbenzofuran 2-keto, 3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-t-butylbenzofuran-2-one, 3-(3,5-dimethyl Benzyl-4-trimethylethenyloxyphenyl)-5,7-di-t-butylbenzofuran-2-one, 3-(3,4-dimethylphenyl)-5,7 - benzofuranone such as di-t-butylbenzofuran-2-one or 3-(2,3-dimethylphenyl)-5,7-di-t-butyl-benzofuran-2-one A compound or the like. The lactone compound of the above form is, for example, a trade name of "HP-136" available from Ciba Japan Co., Ltd.

In the same manner as the cellulose ester, the antioxidant may preferably be contained in the production, or may be removed during storage, such as residual acid, inorganic salt or organic low molecular weight, and preferably has a purity of 99% or more. The residual acid and water are preferably 0.01 to 100 ppm, and the cellulose ester is melt-formed to suppress thermal deterioration, thereby improving film stability, optical properties of the film, and mechanical properties.

In the present invention, it is preferred that the antioxidant is added in an amount of 0.01 to 10% by mass, preferably 0.1 to 5% by mass, more preferably 0.2 to 2% by mass. These two or more types can be used together.

When the amount of the antioxidant added is too small, the stability at the time of melting is lowered, so that the effect cannot be obtained, and when the amount is too large, the transparency of the film is lowered from the viewpoint of compatibility with the cellulose ester, and The film will become brittle and therefore not good.

Acid Capture Agent

The cellulose ester promotes decomposition by acid in a high-temperature environment in which a melt film is formed. Therefore, it is preferable to use an acid scavenger as the stabilizer for the optical film of the present invention. As the useful acid scavenger in the present invention, it is only necessary to react with an acid to make the acid inactive. Among them, a compound having an epoxy group is preferred as described in the specification of U.S. Patent No. 4,137,201. Epoxy compounds as such acid scavengers are known in the art and contain diglycidyl ethers for various polyglycols, especially per 1 gram of polyglycol, by about 8 to 40 moles. Polyethylene glycol derived from condensation of ethylene oxide, diglycidyl ether of glycerin, etc., metal epoxy compound (for example, in a chlorinated vinyl polymer composition, and a chlorinated vinyl polymer composition from Used in the past, epoxidized ether condensation product, diglycidyl ether of bisphenol A (ie, 4,4'-dihydroxydiphenyldimethylmethane), epoxidized unsaturated fatty acid ester ( Particularly, an ester of an alkyl group having 4 to 2 carbon atoms of a fatty acid having 2 to 22 carbon atoms (for example, butyl epoxy stearate), and various epoxidized long-chain fatty acid triglycerides. The composition of (e.g., epoxidized soybean oil, epoxidized linseed oil, etc.) is representative of the epoxidized vegetable oils and other unsaturated natural oils (sometimes referred to as epoxidized natural glycerides or unsaturated fatty acids, these fatty acids are generally Contains 12 to 22 carbon atoms). Further, as the epoxy group-containing epoxide resin compound for sale, EPON 815C and another epoxidized ether oligomer condensation product of the following general formula (E) can be used.

In the formula, n is an integer of 0 to 12. Other acid scavengers which can be used include those described in paragraphs 87 to 105 of JP-A-5-194788.

The acid scavenger is preferably added in an amount of 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, and most preferably 0.5 to 2% by mass. Two or more of them may be used in combination.

Further, the acid scavenger is sometimes referred to as an acid scavenger, an acid scavenger, an acid scavenger or the like for the resin, but these are used in the present invention without any difference.

UV Absorber

The ultraviolet absorber is excellent in ultraviolet absorption energy at a wavelength of 370 nm or less from the viewpoint of preventing deterioration of ultraviolet rays to a polarizer or a display device, and absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. Less is better. Examples of the ultraviolet absorber used in the present invention include an oxybenzophenone-based compound, a benzotriazole-based compound, a salicylate-based compound, a benzophenone-based compound, and a cyanoacrylate-based compound. A nickel-salt-based compound or a triazine-based compound is preferred, but a benzophenone-based compound or a benzotriazole-based compound or a triazine-based compound having less coloration is preferred. In addition, the ultraviolet absorbers described in Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei.

Specific examples of the benzotriazole-based ultraviolet absorber include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and 2-(2'-hydroxy-3', 5'. -di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'- Hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-(3",4",5",6"- Tetrahydroindenidomethyl)-5'-methylphenyl)benzotriazole, 2,2-extended methyl bis(4-(1,1,3,3-tetramethylbutyl) -6-(2H-benzotriazol-2-yl)phenol), 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole , 2-(2'-hydroxy-3'-tert-butyl-5'-(2-octyloxycarbonylethyl)-phenyl)-5-chlorobenzotriazole, 2-(2'- Hydroxy-3'-(1-methyl-1-phenylethyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl)benzotriazole, 2-(2H -benzotriazol-2-yl)-6-(linear and side chain lauryl)-4-methylphenol, octyl-3-[3-tert-butyl-4-hydroxy-5-(chlorine -2H-benzotriazol-2-yl)phenyl]propionate with 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzo Mixture of triazol-2-yl)phenyl]propionate Etc. but not limited thereto.

Further, as a commercial product, TINUVIN 171, TINUVIN 900, TINUVIN 928, and TINUVIN 360 (all manufactured by Ciba Japan Co., Ltd.), LA31 (manufactured by ADEKA Co., Ltd.), and RUVA-100 (manufactured by Otsuka Chemical Co., Ltd.) can be cited.

Specific examples of the benzophenone-based compound include 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and 2-hydroxy-4-methyl. Oxy-5-sulfobenzophenone, bis(2-methoxy-4-hydroxy-5-benzimidylphenylmethane), and the like are not limited thereto.

In the present invention, the ultraviolet absorber is preferably added in an amount of 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, most preferably 0.5 to 2% by mass, based on the resin. These can be used in combination of 2 or more types.

Further, the benzotriazole structure or the triazine structure may be a part of the polymer or a side chain which is regularly a polymer, and may be introduced into other additives such as a plasticizer, an antioxidant, an acid sweeping agent, and the like. Part of the molecular structure.

The ultraviolet ray-absorbing polymer which is known in the art is not particularly limited, and examples thereof include a polymer obtained by separately polymerizing RUVA-93 (manufactured by Otsuka Chemical Co., Ltd.) and a polymer copolymerizing RUVA-93 with another monomer. Specifically, PUVA-30M copolymerized with RUVA-93 and methyl methacrylate at a ratio of 3:7 (mass ratio), PUVA-50M copolymerized at a ratio of 5:5 (mass ratio), etc. . Further, a polymer or the like described in JP-A-2003-113317 can be mentioned.

Plasticizer

In the production of the optical film of the present invention, it is preferred to add at least one plasticizer to the film forming material.

The plasticizer is an additive which is generally added to a polymer to improve the fragility or impart a softening effect. For example, for the cellulose ester of the preferred form of the present invention, the melting temperature is lowered more than the melt temperature alone. The temperature, and at the same heating temperature, lowers the melt viscosity of the material constituting the film containing the plasticizer than the cellulose ester alone, and adds a plasticizer. Further, in order to improve the hydrophilicity of the cellulose ester and to improve the moisture permeability of the optical film, it is possible to add it as a function of preventing moisture penetration.

Here, the melting temperature of the material constituting the film means a temperature at which the material exhibits a fluidity state after being heated. In order for the cellulose ester to undergo a melt flow, it must be heated at least to a temperature higher than the glass transition temperature. When the temperature is above the glass transition temperature, the modulus of elasticity or viscosity is lowered by heat absorption, and fluidity is exhibited. However, at the same time, the cellulose ester has a molecular weight decrease due to melting and thermal decomposition at the same time, and the mechanical properties of the obtained film are adversely affected. Therefore, it is necessary to melt the cellulose ester at a reduced temperature as much as possible. To reduce the melting temperature of the material constituting the film, it is possible to add a plasticizer having a melting point or a glass transition temperature lower than the glass transition temperature of the cellulose ester.

The optical film according to the present invention is an optical film characterized by containing preferably 1 to 25% by mass of a plasticizer. When the amount is less than 1% by mass, the planarity improving effect is not obtained. When the amount is more than 25% by mass, leakage is likely to occur, and the stability of the film with time is lowered, which is not preferable. An optical film having a plasticizer content of 3 to 20% by mass, more preferably 5 to 15% by mass of an optical film, is preferable.

In the present invention, an ester-based plasticizer composed of an ester-based plasticizer composed of a polyhydric alcohol and a monocarboxylic acid, a polyvalent carboxylic acid, and a monohydric alcohol is preferred because it has a high affinity with a cellulose ester.

Examples of the polyhydric alcohol used as a raw material of the preferred ester-based plasticizer of the present invention include, for example, the following, but the present invention is not limited thereto. Examples thereof include ribitol, arabitol, ethylene glycol, glycerin, diglycerin, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, and three Propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1 ,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, double Trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, xylitol, and the like. In particular, ethylene glycol, glycerin or trimethylolpropane is preferred.

Examples of the glycol ester-based plasticizer which is one of the polyol esters include ethylene glycol alkyl ester plasticizers such as ethylene glycol diacetate and ethylene glycol dibutyrate, and ethylene glycol II. Ethylene glycol cycloalkyl ester plasticizers such as cyclopropyl carboxylate and ethylene glycol bicyclohexacarboxylate, ethylene glycol dibenzoate, ethylene glycol di 4-methylbenzoate, etc. Ethylene glycol aryl ester plasticizer. These alkylate groups, cycloalkylate groups, polyaryl groups may be the same or different or may be substituted. Further, it may be a mixture of an alkylate group, a cycloalkylate group, or a polyaryl group, and these substituents may be covalently bonded to each other. The ethylene glycol moiety may also be substituted, and the partial structure of the ethylene glycol ester may be one part of the polymer or regularly become a side chain, and may be introduced into an additive such as an antioxidant, an acid sweeping agent, or an ultraviolet absorber. Part of the molecular structure.

Specific examples of the glyceride-based plasticizer which is one of the polyol esters include glycerin alkyl esters such as triacetin, glyceryl tributyrate, glyceryl diacetate caprylate, and glyceryl ester propionate. Triglyceride such as glycerol tricyclopropyl carboxylate or glycerol tricyclohexyl carboxylate, glycerol tribenzoate, glycerol 4-methyl benzoate, etc. , diglycerin tetrapropionate, diglycerin acetate trioctanoate, diglycerin tetralaurate, etc. diglyceryl alkyl ester, diglyceryl tetracyclobutyl carboxylate, diglycerol tetracyclopentyl carboxylate A diglycerin aryl ester such as a diglycerin cycloalkyl ester such as an acid ester, diglycerin tetrabenzoate or diglycerin 3-methylbenzoate. These alkylate groups, cycloalkylcarboxylate groups, polyaryl groups may be the same or different or may be substituted. Further, it may be a mixture of an alkylate group, a cycloalkylcarboxylate group, a polyaryl group, or these substituents may be covalently bonded to each other. Further, the glycerin and the diglycerin moiety may be substituted, and the partial structure of the glyceride or the diglyceride may be a part of the polymer, or may be a side chain regularly, or may be introduced into an additive such as an antioxidant, an acid sweeping agent, or an ultraviolet absorber. Part of the molecular structure.

Specific examples of the other polyol ester-based plasticizers include the polyol ester-based plasticizers described in paragraphs 30 to 33 of JP-A-2003-12823.

These alkylate groups, cycloalkyl carboxylate groups, and polyaryl groups may be the same or different and may be substituted. Further, it may be a mixture of an alkylate group, a cycloalkylcarboxylate group, a polyaryl group, or these substituents may be covalently bonded to each other. Further, the polyol portion may be substituted, and the partial structure of the polyol may be a part of the polymer, or a side chain regularly, or a molecular structure introduced into an additive such as an antioxidant, an acid sweeping agent, or an ultraviolet absorber. Part.

Among the ester-based plasticizers of the above-mentioned polyol and monocarboxylic acid, an alkyl polyol aryl ester is preferred, and specific examples thereof include the above-mentioned ethylene glycol dibenzoate, glycerin tribenzoate, and The compound 16 is exemplified in glycerol tetrabenzoate, pentaerythritol tetrabenzoate, and paragraph 31 of JP-A-2003-12823.

Specific examples of the dicarboxylic acid ester-based plasticizer which is one of the polycarboxylic acid esters include alkyl dicarboxylates such as dilauryl malonate, dioctyl adipate, and dibutyl sebacic acid. Alkyl dicarboxylic acid cycloalkyl ester plasticizer such as a base ester plasticizer, dicyclopentyl succinate or dicyclohexyl adipate, diphenyl succinate, di 4-methylphenyl pentane Alkyl dicarboxylate aryl esters such as diesters, dihexyl-1,4-cyclohexanedicarboxylate, dimercaptobicyclo[2.2.1]heptane-2,3-dicarboxylic acid a cycloalkylalkyl dicarboxylate-based plasticizer such as an ester, a cycloalkyl group such as dicyclohexyl-1,2-cyclobutanedicarboxylate or dicyclopropyl-1,2-cyclohexyldicarboxylate a cycloalkyl dicarboxylate such as a dicarboxylic acid cycloalkyl ester plasticizer, diphenyl-1,1-cyclopropyldicarboxylate or di-2-naphthyl-1,4-cyclohexanedicarboxylate An aryl group such as an acid aryl ester plasticizer, diethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate or di-2-ethylhexyl phthalate Aryl dicarboxylate plasticizer, dicyclopropyl phthalate, dicyclohexyl decanoate, etc. aryl dicarboxylic acid cycloalkyl ester plasticizer, two Group phthalate, di-4-methylphenyl phthalate and aryl dicarboxylic acid aryl ester based plasticizer. These alkoxy groups and cycloalkoxy groups may be the same or different and may be monosubstituted, and these substituents may be further substituted. The alkyl group, the cycloalkyl group may be a mixture, or these substituents may be covalently bonded to each other. Further, the aromatic ring of phthalic acid may be substituted, and may be a polymer such as a dimer, a trimer or a tetramer. The partial structure of the phthalate may be a part of the polymer, or may be a side chain of the polymer regularly, or may be introduced into a molecular structure of an additive such as an antioxidant, an acid sweeping agent, or an ultraviolet absorber. a part.

Specific examples of the other polycarboxylic acid ester-based plasticizer include alkyl polycarboxylates such as trilauryl tricarboxylate and tributyl-meso-butane-1,2,3,4-tetracarboxylate. Base ester-based plasticizer, tricyclohexyltricarboxylate, tricyclopropyl-2-hydroxy-1,2,3-propane tricarboxylate, alkyl polycarboxylic acid cycloalkyl ester plasticizer, triphenyl Alkyl polycarboxylate aryl ester plasticizer such as 2-hydroxy-1,2,3-propane tricarboxylate or tetrakis 3-methylphenyltetrahydrofuran-2,3,4,5-tetracarboxylate a cycloalkyl polycarboxylic acid alkyl ester such as tetrahexyl-1,2,3,4-cyclobutane tetracarboxylate or tetrabutyl-1,2,3,4-cyclopentane tetracarboxylate a plasticizer, a cycloalkyl polycarboxylic acid cycloalkyl group such as tetracyclopropyl-1,2,3,4-cyclobutane tetracarboxylate or tricyclohexyl-1,3,5-cyclohexyltricarboxylate Ester-based plasticizer, triphenyl-1,3,5-cyclohexyltricarboxylate, hexa-methylphenyl-1,2,3,4,5,6-cyclohexylhexacarboxylate Alkyl polycarboxylate aryl ester plasticizer, trilauryl benzene-1,2,4-tricarboxylate, tetraoctylbenzene-1,2,4,5-tetracarboxylate, etc. Acid alkyl ester plasticizer, tricyclopentylbenzene-1,3,5-tricarboxylate, tetracyclohexyl Aryl-1,2,3,5-tetracarboxylic acid ester, etc. aryl polycarboxylic acid cycloalkyl ester plasticizer triphenylbenzene-1,3,5-tetracarboxylate, hexa-methylphenyl An aryl polycarboxylate aryl ester-based plasticizer such as benzene-1,2,3,4,5,6-hexacarboxylate. These alkoxy groups, cycloalkoxy groups may be the same or different, or 1 substituted, or these substituents may be further substituted. The alkyl group, the cycloalkyl group may be a mixture, or these substituents may be covalently bonded to each other. The aromatic ring of phthalic acid may also be substituted, and may also be a polymer such as a dimer, a trimer or a tetramer. Further, the partial structure of the phthalate may be a part of the polymer, or a side chain which regularly becomes a polymer, or may be introduced into a molecular structure of an additive such as an antioxidant, an acid sweeping agent, or an ultraviolet absorber. a part.

Among the ester-based plasticizers of the above polyvalent carboxylic acid and monohydric alcohol, an alkyl dicarboxylate is preferred, and the above dioctyl adipate is specifically mentioned.

The other plasticizer used in the present invention may, for example, be a phosphate ester plasticizer, a carbohydrate ester plasticizer, a polymer plasticizer or the like.

Specific examples of the phosphate-based plasticizer include alkyl phosphates such as triethylphosphonium phosphate and tributyl phosphate, cycloalkyl phosphates such as tricyclopentyl phosphate and cyclohexyl phosphate, and triphenylphosphoric acid. Ester, cresol phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, trinaphthyl phosphate, three An aryl phosphate such as (xylenyl) phosphate or Ortho-phenyl phosphate. These substituents may be the same or different and may be substituted. Further, it may be a mixture of an alkyl group, a cycloalkyl group, an aryl group, or a substituent which may be covalently bonded to each other.

Further, an alkyl bis(dialkyl phosphate) such as ethyl bis(dimethyl phosphate) or butyl bis (diethyl phosphate), and ethyl bis(diphenyl phosphate) are mentioned. , propyl bis(dinaphthyl phosphate), etc. alkyl bis(diaryl phosphate), phenyl bis(dibutyl phosphate), diphenyl bis (dioctyl phosphate) Iso-aryl bis(dialkyl phosphate), phenyl bis(diphenyl phosphate), naphthyl bis(xylmethyl phosphate) and the like aryl bis(diaryl phosphate) Phosphate ester. These substituents may be the same or different and may be substituted. Further, it may be a mixture of an alkyl group, a cycloalkyl group, an aryl group, or a substituent which may be covalently bonded to each other.

Further, the partial structure of the phosphate ester may be a part of the polymer, or a side chain regularly, or a part of a molecular structure introduced into an additive such as an antioxidant, an acid sweeping agent, or an ultraviolet absorber. Among the above compounds, an aryl phosphate or an aryl bis(diaryl phosphate) is preferred, and specifically, a triphenyl phosphate or a phenyl bis(diphenyl phosphate) is preferred.

Next, a description will be given of a carbohydrate ester-based plasticizer. The carbohydrate is a monosaccharide, disaccharide or trisaccharide in which the sugar is in the form of pyranose or furanose (6-membered ring or 5-membered ring). Non-limiting examples of the carbohydrate include glucose, sucrose, lactose, cellobiose, mannose, xylose, ribose, galactose, arabinose, fructose, sorbose, fibrilose, and raffinose. The carbohydrate hydrate is a compound in which a hydroxyl group of a carbohydrate and a carboxylic acid are dehydrated and condensed to form an ester compound, and specifically, an aliphatic carboxylic acid ester or an aromatic carboxylic acid ester of a carbohydrate. Examples of the aliphatic carboxylic acid include acetic acid and propionic acid. Examples of the aromatic carboxylic acid include benzoic acid, toluic acid, and anisic acid. The number of hydroxyl groups of the carbohydrate differs depending on the type, but a part of the hydroxyl group may react with the carboxylic acid to form an ester compound, or all of the hydroxyl group may react with the carboxylic acid to form an ester compound. In the present invention, it is preferred to form an ester compound by reacting all of the hydroxyl groups with a carboxylic acid.

Specific examples of the carbohydrate hydrate-based plasticizer include glucose pentaacetate, glucose pentapropionate, glucose pentabutyrate, sucrose octaacetate, and sucrose octabenzoate, among which sucrose is eight. Acetate and sucrose octabenzoate are preferred, and sucrose octabenzoate is particularly preferred.

An example of such a compound is as follows, but the present invention is not limited to the same.

Monobit SB: First Industrial Pharmaceutical Company

Monobit SOA: First Industrial Pharmaceutical Company

Specific examples of the polymer plasticizer include an aliphatic hydrocarbon-based polymer, an alicyclic hydrocarbon-based polymer, polyethyl acrylate, polymethyl methacrylate, methyl methacrylate, and methacrylic acid-2. a vinyl polymer such as an acrylic polymer, a polyvinyl isobutyl ether or a poly N-vinyl pyrrolidone such as a copolymer of hydroxyethyl ester (for example, a copolymerization ratio of any ratio of 1:99 to 99:1) Polystyrene, polystyrene, polystyrene succinate, polyethylene terephthalate, polyethylene naphthalate, polyester, polyethylene oxide, poly Polyether such as propylene oxide, polyamine, polyurethane, polyurea, and the like. The number average molecular weight is preferably from 1,000 to 500,000, particularly preferably from 5,000 to 200,000. When it is less than 1,000, the problem of volatility occurs, and when it exceeds 500,000, the plasticizing ability is lowered, which adversely affects the mechanical properties of the optical film. These polymer plasticizers may be individual polymers formed from one repeating unit, or may be copolymers having a plurality of repeating structures. These polymers may be used in combination of two or more kinds.

The amount of the other plasticizer added is usually 0.1 to 50 parts by mass, preferably 1 to 30 parts by mass, more preferably 3 to 15 parts by mass, per 100 parts by mass of the cellulose ester.

In the optical film of the present invention, an ester-based plasticizer composed of a polyhydric alcohol and a monocarboxylic acid, an ester-based plasticizer composed of a polyvalent carboxylic acid and a monohydric alcohol is preferably contained in an amount of 1 to 25% by mass, and may be used in combination. A plasticizer other than this.

For the optical film of the present invention, an ester-based plasticizer composed of a polyhydric alcohol and a monocarboxylic acid is more preferable, and an ester-based plasticizer having a trivalent or higher alcohol and a monovalent carboxylic acid is used for the cellulose ester. It has high compatibility and can be added at a high addition rate. Therefore, even if other plasticizers or additives are used in combination, no leakage occurs, and other plasticizers or additives can be easily used as appropriate.

Further, when the optical film of the present invention affects optical use when colored, the yellowness (yellow index YI) is preferably 3.0 or less, preferably 1.0 or less, and the yellowness can be measured in accordance with JIS-K7103.

"matting agent"

In the optical film of the present invention, a matting agent may be added in order to impart a lubricity or an optical or mechanical function. Examples of the matting agent include fine particles of an inorganic compound or fine particles of an organic compound.

The shape of the matting agent may be a spherical shape, a rod shape, a needle shape, a layer shape, a flat shape or the like. Examples of the matting agent include metals such as ceria, titania, alumina, zirconia, calcium carbonate, clay, talc, calcined calcium citrate, hydrated calcium citrate, aluminum citrate, magnesium citrate, and calcium phosphate. Inorganic fine particles such as oxides, phosphates, citrates, and carbonates or crosslinked polymer fine particles. Among them, it is preferable to reduce the haze value of the film by using cerium oxide. These fine particles can be preferably treated by an organic substance because the haze value of the film can be lowered.

The surface treatment is preferably carried out with a halogenated alkane, an alkoxydecane, a hydrazine nitrogen, a decane or the like. The larger the average particle diameter of the fine particles, the larger the smoothness effect, and conversely, the smaller the average particle diameter, the more excellent the transparency. Further, the average particle diameter of the primary particles of the fine particles is in the range of 0.01 to 1.0 μm. The average particle diameter of the primary particles of the preferred fine particles is preferably 5 to 50 nm, more preferably 7 to 14 nm. It is preferred that the fine particles form an unevenness of 0.01 to 1.0 μm on the surface of the optical film.

Examples of the fine particles of cerium oxide include AEROSIL (AEROSIL) 200, 200V, 300, R972, R972V, R974, R202, R812, OX50, TT600, and NAX50 manufactured by Japan AEROSIL Co., Ltd. - P10, KE-P30, KE-P100, KE-P150, etc., preferably AEROSIL 200V, R972V, NAX50, KE-P30, KE-P100. These fine particles may be used in combination of two or more kinds.

When two or more types are used in combination, they can be used after mixing at any ratio. The fine particles having an average particle diameter or a different material are used, for example, in a range in which the mass ratio of AEROSIL 200V and R972V is from 0.1:99.9 to 99.9:0.1.

The method of adding these matting agents may preferably be carried out by kneading or the like. Further, in another embodiment, the matting agent previously dispersed in the solvent and the resin and/or the plasticizer and/or the antioxidant and/or the ultraviolet absorber are mixed and dispersed, and then the solvent is volatilized or precipitated to obtain a solid matter, and this is used. In the production process of the resin melt, it is preferred from the viewpoint that the matting agent can be uniformly dispersed in the resin.

In order to improve the mechanical, electrical, optical and other characteristics of the film, the above matting agent can be added.

Further, the addition of these fine particles improves the smoothness of the obtained film, but increases the haze value when added. Therefore, the content of the resin is preferably 0.001 to 5% by mass, preferably 0.005 to 1% by mass, based on the resin. More preferably, it is 0.01 to 0.5% by mass.

Further, as the optical film of the present invention, when the haze value exceeds 1.0%, it may be affected as an optical material, and it is preferable that the haze value is less than 1.0%, preferably less than 0.5%. The haze value can be measured in accordance with JIS-K7136.

The material constituting the film requires less or no generation of volatile components in the melting and film forming steps. This foaming upon heating and melting can reduce or avoid defects in the interior of the film or planarity deterioration of the surface of the film.

The content of the volatile component at the time of melting of the material constituting the film is 1% by mass or less, preferably 0.5% by mass or less, more preferably 0.2% by mass or less, and most preferably 0.1% by mass or less. In the present invention, a differential thermal weight measuring device (TG/DTA200 manufactured by Seiko Instruments Inc.) is used to obtain a heating loss from 30 ° C to 250 ° C, and the amount thereof is a content of a volatile component.

The material constituting the film to be used is preferably a volatile component represented by the above-mentioned water or the above-mentioned solvent, before or during film formation. The removal method can be carried out by a heating method such as a known drying method, a pressure reduction method, a heating and pressure reduction method, or the like, or can be carried out in the air or as an inert gas to select an atmosphere of nitrogen. When these known drying methods are carried out, the quality of the film can be improved when it is carried out in a temperature region where the material constituting the film does not decompose.

When drying is performed before the film formation, the generation of the volatile component can be reduced, and the resin can be separated into a mixture or a mixture of at least one of the resin and the resin and the material constituting the film, and then dried. The drying temperature is preferably 70 ° C or more. When a material having a glass transition temperature is present on the dried material, when it is heated to a drying temperature higher than the glass transition temperature, the material is melted and processed, and the drying temperature is preferably at or below the glass transition temperature. When the plural substance has a glass transition temperature, it is based on the glass transition temperature at which the glass transition temperature is low. It is preferably 70 ° C or more, (glass transition temperature - 5) ° C or less, more preferably 110 ° C or more, (glass transition temperature - 20) ° C or less. The drying time is preferably from 0.5 to 24 hours, preferably from 1 to 18 hours, more preferably from 1.5 to 12 hours. When the drying temperature is too low, the removal rate of the volatile component is lowered, and the drying time is too long. Further, the drying step may be carried out in two or more stages. For example, the drying step may include a preliminary drying step for storing the material, and a pre-drying step before the film formation to one week before the film formation.

Melt Casting Method

A preferred embodiment of the optical film of the cellulose ester of the present invention is preferably produced by melt casting as described above. The solvent used in the solution casting method (for example, methylene chloride or the like) is not used, and the molding method by melt-melting by heating and melting is more specifically classified into a melt extrusion molding method, a pressure molding method, and an expansion method. Injection molding method, blow molding method, extension molding method, and the like. Among them, a melt-pressing method is preferred because a polarizing plate protective film excellent in mechanical strength and surface precision can be obtained.

Hereinafter, a method of producing an optical film of the present invention will be described by taking a melt extrusion method as an example.

Fig. 1 is a schematic flow chart showing the entire apparatus constituting the method for producing an optical film according to the present invention, and Fig. 2 is an enlarged view showing a portion from a casting die to a cooling roll.

1 and 2, the optical film of the present invention is produced by mixing a film material such as cellulose ester, and then extruding the film from the casting die 4 to the first cooling roll 5 using the extruder 1. When the first cooling roller 5 is circumsed, the third cooling roller 7 and the third cooling roller 8 are connected to each other in the order of three cooling rolls, and the film 10 is obtained by cooling and solidifying. Next, the film 10 which has been peeled off by the peeling roller 9 is sandwiched between the both end portions of the film by the stretching device 12, and then stretched in the width direction, and taken up by the winding device 16. Further, in order to correct the planarity, a contact roller 6 that presses the molten film on the surface of the first cooling roll 5 is provided. The contact roller 6 has elasticity on the surface and forms a nip between the first cooling roller 5. The details of the contact roller 6 will be described later.

In the method for producing an optical film of the present invention, the conditions of the melt extrusion are carried out under the same conditions as those used for thermoplastic resins such as other polyesters. The material is preferably pre-dried. The water is dried to 1000 ppm or less, preferably 200 ppm or less, in a vacuum or a vacuum dryer or a dehumidifying hot air dryer.

For example, the cellulose ester-based resin which has been dried by hot air or vacuum or under reduced pressure is melted to an extrusion temperature of about 200 to 300 ° C, and then filtered by a vane type filter 2 or the like to remove foreign matter.

When the feed hopper (not shown) is introduced into the extruder 1, it is preferable to prevent oxidative decomposition or the like under vacuum or under reduced pressure or in an inert gas atmosphere.

When the additives such as a plasticizer are not previously mixed, these may be kneaded in the middle of the extruder. In order to allow it to be uniformly added, a mixing device such as a static mixer 3 may be preferably used.

In the present invention, the cellulose ester-based resin and other additives such as a stabilizer which must be added are preferably mixed before melting, and it is more preferable to mix the cellulose ester-based resin and the additive before heating. The mixing is carried out using a mixer or the like, and mixing may be carried out in the cellulose ester preparation process as described above. When a mixer is used, a general mixer such as a V-type mixer, a conical spiral type mixer, a horizontal cylinder type mixer, a Henschel mixer, or a ribbon mixer can be used.

After mixing the materials constituting the film as described above, the mixture may be directly melted by using the extruder 1 to form a film. However, once the material constituting the film is granulated, the particles are melted by the extruder 1 to form a film. . Further, when the material constituting the film contains a plurality of materials having different melting points, only the material having a lower melting point can be made into a so-called rice-like semi-melt at the melting temperature, and the semi-melt can be introduced into the extruder 1 After film formation. When the material constituting the film contains a material which is easily thermally decomposed, a method of directly forming a film without forming the film or a method of forming a film like the above-described rice-through semi-molten is preferable for the purpose of reducing the number of times of melting.

The extruder 1 is a type of extruder which can be used commercially, but a melt-kneading extruder is preferred, and a single-axis extruder is preferably a 2-axis extruder. When the film is formed directly from the material constituting the film, it is necessary to use a two-axis extruder because the kneading degree is necessary. Therefore, even if a single-axis extruder is used, the spiral shape can be changed to Maddock type. It can be used because it is moderately kneaded under the spiral of a mixed type such as Unimelt type or Dulmage. As the material constituting the film, when a pellet or a rice-like semi-melt is used, a uniaxial extruder or a 2-axis extruder can be used.

The cooling step in the extruder 1 and after the extrusion may be replaced by an inert gas such as nitrogen or the oxygen concentration may be preferably lowered by pressure reduction.

The melting temperature of the material constituting the film in the extruder 1 is preferably different depending on the viscosity or discharge amount of the material constituting the film, the thickness of the sheet to be produced, and the like, and is generally Tg or more for the glass transition temperature Tg of the film. Tg + 100 ° C or less, preferably Tg + 10 ° C or more, Tg + 90 ° C or less. The melt viscosity at the time of extrusion is from 1 to 10,000 Pa s, preferably from 10 to 1,000 Pa s. Further, it is preferable that the material constituting the film in the extruder 1 has a shorter residence time, and is usually within 5 minutes, preferably within 3 minutes, more preferably within 2 minutes. The residence time is limited by the type of the extruder 1 and the extrusion conditions, and can be shortened by adjusting the supply amount of the material, the L/D, the number of spiral rotations, the depth of the spiral groove, and the like.

The spiral shape or the number of rotations of the extruder 1 and the like are appropriately selected by the viscosity or the discharge amount of the material constituting the film. In the present invention, the cutting speed of the extruder 1 is from 1/sec to 10000/sec, preferably from 5/sec to 1000/sec, more preferably from 10/sec to 100/sec.

As the extruder 1 used in the present invention, a general plastic molding machine can be used.

The material constituting the film extruded by the extruder 1 is sent to the casting mold 4, and the film is extruded from the slit of the casting mold 4. The casting mold 4 is used only for producing a sheet or a film, and is not particularly limited. Examples of the material of the casting mold 4 include hard chromium, chromium carbide, chromium nitride, titanium carbide, titanium carbonitride, titanium nitride, ultra-steel, ceramics (tungsten carbide, aluminum oxide, chromium oxide). For the surface treatment, the surface is processed by grinding with a grinding stone of #1000 or less, and using a diamond grinding stone of #1000 or more (the cutting direction is perpendicular to the flow direction of the resin). , electrolytic polishing, electrolytic composite grinding and other processing. The preferred material of the lip portion of the casting mold 4 is the same as that of the casting mold 4. Further, the surface precision of the lip portion is preferably 0.5 S or less, and preferably 0.2 S or less.

The slit of the casting mold 4 is configured to adjust the interval. As shown in Figure 3. One of the pair of lips forming the slit 32 of the casting mold 4 is a flexible lip 33 which is less rigid and easily deformed, and the other is a fixed lip 34. Most of the heating bolts 35 are arranged at a certain interval in the width direction of the casting mold 4, that is, in the longitudinal direction of the slit 32. Each of the heating bolts 35 is provided with a block 36 having a charge electric heater 37 and a cooling medium passage, and each of the heating bolts 35 penetrates each block 36 in the longitudinal direction. The base of the heating bolt 35 is fixed to the mold body 31, and the tip end is connected to the outer surface of the flexible lip 33. On the other hand, the block 36 is cooled by a general air conditioner, and the input force of the electric heater 37 is increased or decreased, and the temperature of the block 36 is adjusted, whereby the heating bolt 35 is thermally expanded and contracted, and the flexible lip 33 is displaced to adjust the film thickness. A thickness gauge is provided at a desired position after the molding, whereby the detected fabric thickness information is fed back to the control device, and the thickness information is compared with the set thickness information by the control device, and the correction control amount from the same device can be used. The signal is used to control the power or operating rate of the heating element of the heating bolt. The heating bolts preferably have a length of 20 to 40 cm and a diameter of 7 to 14 mm. For example, a plurality of plural heating bolts are arranged at a preferred pitch of 20 to 40 mm. Instead of the heating bolt, it may be disposed in the axial direction to manually move it back and forth to adjust the slit spacing as a main body spacing adjusting member. The gap interval adjusted by the interval adjusting member is generally 200 to 1000 μm, preferably 300 to 800 μm, more preferably 400 to 600 μm.

The first to third cooling rolls are made of seamless steel pipe having a wall thickness of about 20 to 30 mm, and the surface is mirror-finished. A pipe into which the coolant flows is disposed inside, and the pipe is configured to absorb heat from the film on the roll by the inflowing coolant.

On the other hand, the contact roller 6 coupled to the first cooling roller 5 has elasticity on its surface, and is deformed along the surface of the first cooling roller 5 by the pressure of the first cooling roller 5, and is interposed between the first roller 5 and the first roller 5. A nip is formed. The contact roller 6 is also referred to as a rolling rotor. As the contact roller 6, a contact roller disclosed in Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. 3,194, 904, No. 2,342, 798, No. 2002-36332, No. 2002-36333, and the like can be used. These can be used by purchasers. These are explained in more detail below.

Fig. 4 is a cross-sectional view showing an example of a rolling rotor. (Schematic section of the first example of the touch roll 6 (hereinafter referred to as the contact roll A)). The contact roller A is a member in which the elastic roller 42 is disposed inside the flexible metal sleeve 41 as shown.

The metal sleeve 41 is made of stainless steel having a thickness of 0.3 mm and has flexibility. When the metal sleeve 41 is too thin, the strength is insufficient, and if it is too thick, the elasticity is insufficient. Therefore, the thickness of the metal sleeve 41 is preferably 0.1 to 1.5 mm. The elastic roller 42 is provided with an elastic body 44 on the surface of the metal inner cylinder 43 that is rotatably driven by the bearing. When the contact roller A is pressurized on the first cooling roller 5, the elastic roller 42 is pressurized by the metal sleeve 41 on the first cooling roller 5, and the metal sleeve 41 and the elastic roller 42 are corresponding to the first cooling roller 5. Deformed in a similar shape to form a nip between the first cooling roll. Cooling water 45 flows into the space formed between the elastic rollers 42 inside the metal sleeve 41.

Fig. 5 is a cross-sectional view showing a vertical plane on the rotating shaft shown in the second example of the rolling rotor (hereinafter referred to as the contact roller B).

Fig. 6 is a cross-sectional view showing a plane of a rotation axis of a second example (contact roller B) including a rolling rotor.

In Fig. 5 and Fig. 6, the contact roller B is flexible, and the outer cylinder 51 made of a seamless stainless steel pipe (thickness: 4 mm) and the high-rigidity metal inner cylinder 52 which is disposed in the same axial direction as the inner side of the outer cylinder 51 are provided. The schematic structure. The coolant 54 flows into the space 53 between the outer cylinder 51 and the inner cylinder 52. Specifically, the contact roller B is provided with outer cylinder support flanges 56a, 56b at the both end rotation shafts 55a, 55b, and the outer peripheral portions of the outer cylinder support flanges 56a, 56b are installed. Upper thin-walled metal outer cylinder 51. Further, the fluid supply pipe 59 is formed in the same axial center in the fluid discharge hole 58 of the fluid return passage 57 formed in the axial center portion of the one rotation shaft 55a, and the fluid supply pipe 59 is connected and fixed to the thin metal. The fluid shaft cylinder 60 disposed on the axial center portion of the cylinder 51 is disposed. Inner cylinder support flanges 61a, 61b may be respectively attached to both end portions of the fluid barrel 60, and the outer cylinder support flanges 56b are attached from the outer portions of the inner cylinder support flanges 61a, 61b to the other end side outer cylinder support flanges 56b. A metal inner cylinder 52 having a wall thickness of about 15 to 20 mm. Between the metal inner cylinder 52 and the thin metal outer cylinder 51, for example, a cooling liquid flow space 53 of about 10 mm is formed, and in the metal inner cylinder 52, a communication flow space 53 and a space are formed in the vicinity of both end portions. The cylinder supports the outflow ports 52a of the intermediate passages 62a and 62b on the outer sides of the flanges 61a and 61b, and the inflow port 52b.

Further, the outer cylinder 51 has a flexibility, flexibility, and restorability similar to the elasticity of the rubber, and is thinned in a range in which the thin-walled cylinder theory of elasticity is applicable. The flexibility evaluated by the thin-walled cylinder theory is expressed by the ratio of the wall thickness t/roller radius r, and the smaller the ratio of t/r, the higher the flexibility. In the contact roll B, when t/r ≦ 0.03, flexibility is an optimum condition. The contact rolls generally used generally have a horizontally long shape of a roll diameter R = 200 to 500 mm (roller radius r = R / 2) and a roll effective width L = 500 to 1600 mm at r/L < As shown in FIG. 6, for example, when the roll diameter R=300 mm and the roll effective width L=1200 mm, the optimum range of the wall thickness t is 150×0.03=4.5 mm or less, but the average line pressure is 1300 mm for the molten sheet width. When clamping at 98 N/cm, compared with the rubber roller of the same shape, the rebound ratio is equal when the wall thickness of the outer cylinder 51 is 3 mm, and the nip of the roller rotation direction of the outer cylinder 51 and the nip of the cooling roller The width k is also about 9 mm, and the nip width of the rubber roller shows a value close to about 12 mm, and it is known that it can be pinched under the same conditions. Further, the amount of deflection in the nip width k is about 0.05 to 0.1 mm.

In particular, when t/r ≦ 0.03, when the roll diameter is generally R: 200 to 500 m m, particularly in the range of 2 mm ≦ t ≦ 5 mm, sufficient flexibility can be obtained, and the thickness of the machine is reduced. It is easy to implement and becomes extremely practical. When the wall thickness is 2 mm or less, the elastic deformation during processing cannot be processed with high precision.

The converted value of 2 mm ≦t ≦ 5 mm is 0.008 ≦t/r ≦ 0.05 for the normal roll diameter, but is practically proportional to the roll diameter and the wall thickness is also increased under the condition of t/r ≒ 0.03. It is better. For example, the roll diameter is selected from the range of R=200, t=2 to 3 mm, roll diameter: R=500, and t=4 to 5 mm.

The contact rolls A and B are supplied with energy toward the first cooling roll by an energizing means (not shown). The supply capacity of the energy supply means is F, and the value of the width W of the film of the nip along the rotation axis direction of the first cooling roll 5 = F/W (line pressure) is set to 9.8 to 147 N. /cm. In the embodiment of the present embodiment, a nip is formed between the contact rolls A and B and the first cooling roll 5, and the nip may be corrected to planarity between the passages of the film. Therefore, the contact roller is composed of a rigid body, and the nip is not formed between the first cooling roller, and the film is nip under a small linear pressure for a long time, so that the planarity can be more reliably corrected. That is, if the line pressure is less than 9.8 N/cm, the plastic film line cannot be sufficiently eliminated. On the contrary, when the line pressure is larger than 147 N/cm, the film does not easily pass through the nip, and the film thickness is liable to cause unevenness.

Further, when the surfaces of the contact rolls A and B are made of metal, the surfaces of the rolls A and B can be smoothly smoothed compared with the case where the surface of the contact roll is made of rubber, so that a film having high smoothness can be obtained. Further, as the material of the elastic body 44 of the elastic roller 42, an ethylene-propylene propylene rubber, a neoprene rubber, a ruthenium rubber or the like can be used.

However, it is important to eliminate the plastic film line by the contact roller 6, and it is important that the film viscosity when the contact roller 6 pinches the film must be an appropriate range. Further, it is known that the cellulose ester has a large viscosity change due to temperature. Therefore, it is important that the viscosity at the time of pressing the optical film by the touch roll 6 is set to an appropriate range, and it is important that the film temperature at the time of the contact roll 6 pinching the cellulose film is set to an appropriate range. When the glass transition temperature of the optical film is Tg, it is preferable that the film is pressed against the film temperature T before the contact roll 6 so as to satisfy the condition of Tg < T < Tg + 110 °C. If the film temperature T is lower than Tg, the film viscosity will be too high to correct the film line. Conversely, if the temperature T of the optical film is higher than Tg + 110 ° C, the surface of the film and the roller cannot be uniformly adhered, and the film line cannot be corrected. It is preferably Tg + 10 ° C < T2 < Tg + 90 ° C, more preferably Tg + 20 ° C < T2 < Tg + 70 ° C. When the temperature of the film when the contact roll 6 is pressed against the optical film is set to an appropriate range, the melt extruded from the casting die 4 is adjusted along the first cooling roll 5 by the position P1 in contact with the first cooling roll 5. The length L of the first cooling roller 5 of the nip of the contact roller 6 in the rotational direction may be sufficient.

In the present invention, preferred materials of the first cooling roll 5 and the second cooling roll 7 include carbon steel, stainless steel, resin, and the like. Further, the surface precision is preferably high, and the surface roughness is 0.3 S or less, preferably 0.01 S or less.

In the present invention, it is preferable to reduce the correction effect of the plastic film line by reducing the pressure from the lip of the casting mold 4 to the portion of the first cooling roll 5 to 70 kPa or less. Preferably, the reduced pressure is 50 to 70 kPa. The method of maintaining the partial pressure of the lip from the lip of the casting die 4 to the first cooling roller 5 at 70 kPa or less is not particularly limited, and the self-casting die 4 is covered with a pressure-resistant member and decompressed around the roller. And other methods. In this case, it is preferable that the suction device is disposed so that the device does not become a place where the sublimate adheres, and the heater is applied to perform heating or the like. In the present invention, if the suction pressure is too small, the sublimate is not effectively attracted, so that it is necessary to have an appropriate suction pressure.

In the present invention, the film-form cellulose ester-based resin in a molten state from the casting die 4 is conveyed in a dense manner in the order of the first cooling roll 5, the second cooling roll 7, and the third cooling roll 8, and This was cooled and solidified to obtain an unstretched cellulose ester-based resin film 10.

In the embodiment of the present invention shown in Fig. 1, the cooled and solidified unstretched film 10 which is peeled off from the third cooling roll 8 by the peeling roller 9 is introduced into the stretching machine 12 via a dancer roll (film tension adjusting roll) 11. Here, the film 10 is stretched in the lateral direction (wide direction). By this extension, the molecules in the film are aligned.

A method of extending the film in the width direction can be carried out by a method such as a known tenter. In particular, it is preferred that the extending direction is the width direction and the lamination of the polarizing film can be carried out in the form of a roll. When extending in the width direction, the retardation axis of the optical film formed of the cellulose ester resin is broad.

On the one hand, the transmission axis of the polarizing film is generally also in the width direction. The polarizing plate of the polarizing film is parallel to the slow axis of the optical film, and the laminated polarizing plate is incorporated into the liquid crystal display device, thereby improving the display contrast of the liquid crystal display device and obtaining a good viewing angle.

The glass transition temperature Tg of the material constituting the film can be controlled by the difference in the kind of the material constituting the optical film and the ratio of the materials constituting the film. When a retardation film is produced as an optical film, the Tg is 120 ° C or higher, preferably 135 ° C or higher. In the liquid crystal display device, in the developing state of the image, the temperature of the device itself rises, for example, the temperature rise from the light source causes the temperature environment of the film to change. At this time, when the Tg of the optical film is lower than the ambient temperature of the film, the hysteresis value caused by extending the molecular alignment state fixed inside the film and the dimensional shape of the film greatly change. When the Tg of the film is too high, the temperature at which the material constituting the film is thinned is too high, and the energy consumption for heating is increased, and the material itself is decomposed when the film is formed, and coloring is caused thereby, so the Tg is 250. Below °C is preferred.

Further, in the extending step, known heat setting conditions, cooling, and relaxation treatment may be performed, and the characteristics required for the optical film according to the purpose may be appropriately adjusted.

The function of the phase difference film when the physical properties of the retardation film and the viewing angle of the liquid crystal display device are to be enlarged can be appropriately selected by the above-described stretching step and heat setting treatment. When the stretching step and the heat setting treatment are included, the heating and pressing step may be performed before the stretching step and the heat setting treatment.

When the optical film of the present invention is used as a retardation film and further as a phase difference film which functions as a composite polarizing plate protective film, it is necessary to perform refractive index control, and this refractive index control is preferably a stretching method. The extension method will be described below.

In the step of extending the retardation film, the necessary retention values Ro and Rt can be controlled by extending 1.0 to 2.0 times in the direction of the cellulose ester and increasing the elongation in the film plane by 1.01 to 2.5 times. Where Ro is the in-plane hysteresis value and Rt is the thickness direction hysteresis value.

The stagnation values Ro and Rt can be obtained by the following formula.

Formula (i)Ro=(nx-ny)×d

Formula (ii) Rt=((nx+ny)/2-nz)×d

(wherein nx represents the refractive index in the direction of the retardation axis in the plane of the film, ny represents the refractive index in the direction of the phase axis of the film, and nz represents the refractive index in the thickness direction of the film (refractive index at 23 ° C, 55% RH) In the environment, measured at a wavelength of 590 nm), d represents the film thickness (nm).

The refractive index of the optical film was measured using an Abbe refractometer (4T), the thickness of the film was measured using a commercially available micrometer, and the hysteresis value was measured using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.).

The extension can be carried out, for example, for the long direction of the film and in the direction of the film in the direction of the film, i.e. for the width direction, successively or simultaneously. At this time, if the stretching ratio in at least one direction is too small, a sufficient phase difference cannot be obtained, and when it is too large, stretching becomes difficult and film breakage occurs.

For example, when extending in the direction of the melt casting (longitudinal direction), if the shrinkage in the width direction is too large, the value of nz may be too large. At this time, it is suppressed that the width of the film is shrunk or extended in the width direction. When extending in the width direction, uneven refractive index distribution occurs in the width direction. This distribution sometimes occurs when the tenter method is used, and it is presumed that when the film is stretched in the width direction, a contraction force is generated in the central portion of the film, and the end portion is fixed, which causes a so-called bowing. phenomenon. At this time, when the stretching is also performed in the casting direction, the bowing phenomenon can be suppressed, and the uneven distribution of the phase difference in the width direction can be reduced.

By extending in the two-axis directions parallel to each other, the film thickness variation of the obtained optical film can be reduced. When the film thickness of the retardation film is excessively changed, the phase difference is uneven, and when used in a liquid crystal display, it may cause unevenness in coloring or the like.

The film thickness variation of the optical film is ±3%, more preferably ±1%. In the above object, the method of extending in the two-axis direction orthogonal to each other is effective, and the stretching ratio in the two-axis direction orthogonal to each other is 1.0 to 2.0 times in the final casting direction and 1.01 to 2.5 times in the width direction. The range is preferably, and it is more preferable to obtain a retention value which is required to be in the range of 1.01 to 1.5 times in the casting direction and 1.05 to 2.0 times in the width direction.

When the absorption axis of the polarizer exists in the longitudinal direction, the transmission axis of the polarizer can be made uniform in the width. It is preferable to laminate the long-length polarizing plate in a roll-to-roll manner, and it is preferable that the retardation film is stretched in the width direction to obtain a slow phase axis.

When a cellulose ester obtained by positive birefringence is used for stress, when the above-described structure is extended in the width direction, the retardation axis of the retardation film can impart stress in the width direction. At this time, in order to improve the display quality, the retardation axis of the retardation film is preferably in the width direction, and the retention value of the desired target must be satisfied.

Formula: (stretching ratio in the width direction) > (stretching ratio in the casting direction)

The conditions.

After the extension, the end portion of the film is cut by the slitting machine 13 as a slit of the width of the product, and then the flange processing is performed by the edge ring 14 and the back roller 15, and the edge processing is performed on both ends of the film. (knurled, embossing), being taken up by the winder 16, preventing the occurrence of sticking or scratching in the optical film (element) F. The method of burring can process a metal ring having a convex and concave pattern on the side by heating or pressurizing. Moreover, the holding portion of the press plate at both ends of the film is generally deformed and cannot be used as a film product, so that it can be reused as a raw material after being cut.

Continuing, the film winding step is such that the film is wound on the take-up reel by keeping the shortest distance between the outer circumferential surface of the cylindrical roll film and the outer peripheral surface of the previous movable conveyance roller constant. Further, before the take-up reel, means such as a static eliminating fan that removes or reduces the surface potential of the film may be provided.

The coiler for manufacturing the optical film of the present invention can be used by a general user, and can be wound by a winding method such as a constant tension method, a constant torque method, a tilting tension method, or a program tension control method with a constant internal stress. Further, the initial winding tension at the time of winding up the polarizing plate protective film is preferably from 90.2 to 300.8 N/m.

In the method of the present invention, in the winding step of the film, it is preferred to wind up the film under the environmental conditions of a temperature of 20 to 30 ° C and a humidity of 20 to 60% RH. By specifying the temperature and humidity of the film winding step, the humidity change resistance in the thickness direction retention value (Rt) can be improved.

When the temperature in the winding step is less than 20 ° C, wrinkles are generated, and the deterioration of the film roll quality is not practical and is not preferable. When the temperature in the winding step of the film exceeds 30 ° C, wrinkles are still generated, and the film roll quality is deteriorated, which is not practical.

Further, if the humidity in the winding step of the film is less than 20% RH, static electricity is likely to be generated, and the deterioration of the film roll quality is not practical and is not preferable. When the humidity in the winding step of the film exceeds 60% RH, the roll quality, the bonding failure, the conveyability, and the like may be deteriorated.

When the polarizing plate protective film is wound into a roll shape, the core of the roll may be only the core on the cylinder, and may be any material, but is preferably a hollow plastic core, which is resistant to plastic material. The heat-resistant plastic material having a heat treatment temperature may be a resin such as a phenol resin, a xylene resin, a melamine resin, a polyester resin or an epoxy resin. Further, it is preferred to use a reinforced thermosetting resin such as a glass fiber. For example, a hollow plastic core: an outer diameter of 6 inches using FRP (hereinafter, the inch indicates 2.54 cm). , the core of the inner diameter of 5 inches.

The number of the cores of these rolls is preferably 100 or more, more preferably 500 or more, and more preferably 5 cm or more, and the width of the film substrate is preferably 80 cm or more, and more preferably 1 m or more.

The thickness of the optical film of the present invention varies depending on the purpose of use, but it is preferably 10 to 500 μm as the finished optical film. In particular, the lower limit is 20 μm or more, preferably 35 μm or more. Further, the upper limit is preferably 150 μm or less, and more preferably 120 μm or less. It is particularly preferably 25 to 90 μm. When the retardation film has a polarizing plate protective film, if the film is too thick, the polarizing plate after the polarizing plate is processed is too thick, and the liquid crystal display used in a notebook computer or a portable electronic device cannot be applied to a particularly thin and lightweight film. The purpose. On the other hand, when the film is too thin, it is difficult to exhibit the hysteresis value of the retardation film, and the moisture permeability of the film becomes high, which makes the protection ability in the polarizer humidity lower, which is not preferable.

When the retardation axis or the phase axis of the retardation film exists in the film surface, and the angle formed by the film formation direction is θ1, θ1 is -1 to +1 °, preferably -0.5 to +0.5 °.

The θ1 is defined as the alignment angle, and the measurement of θ1 can be performed using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.).

When θ1 satisfies each of the above relationships, a preferred luminance in the display image can be obtained, and light leakage can be suppressed or prevented, and a faithful color reproduction can be obtained for the color liquid crystal display device.

When the retardation film is a VA type having a wide viewing angle, the retardation film is disposed such that the phase axis of the retardation film is placed in the region as θ1, thereby improving display quality and being used as a polarizing plate and a liquid crystal display device. In the case of the MVA type, for example, the configuration shown in Fig. 7 can be used.

In Fig. 7, 21a and 21b are protective films, 22a and 22b are retardation films, 25a and 25b are polarizers, 23a and 23b are the retardation axes of the film, and 24a and 24b are the transmission axis directions of the polarizers, 26a. 26b is a polarizing plate, 27 is a liquid crystal cell, and 29 is a liquid crystal display device.

The retention Ro distribution in the in-plane direction of the optical film is preferably 5% or less, preferably 2% or less, and particularly preferably 1.5% or less. Further, the distribution of the retained Rt in the thickness direction of the film is preferably 10% or less, more preferably 2% or less, and particularly preferably 1.5% or less.

In the retardation film, the variation in the distribution of the retention value is preferably small. When a polarizing plate containing a retardation film in a liquid crystal display device is used, when the variation in the retention distribution is small, it is preferable from the viewpoint of preventing color unevenness.

Adjusting the retardation film to have a retention value suitable for improving the quality of the liquid crystal cell of the VA form or the TN form, and particularly for dividing the VA form into the above multiple regions and applying the MVA form, adjusting the in-plane retention ratio of Ro 30 nm is 95 nm or less, and the thickness direction retention Rt is adjusted to be larger than 70 nm and 400 nm or less.

The in-plane retention Ro is such that two polarizing plates are disposed in a crossed Nicol, and liquid crystal cells are disposed between the polarizing plates. For example, when the configuration is as shown in FIG. 7 , when viewed from the normal direction of the display surface, when viewed in the crossed Nicols state, when viewed from the slope of the normal line of the display surface, the polarizing plate is crossed. The Cole state produces a deviation, which compensates for the light leakage caused by this. The retention in the thickness direction Rt is in the above TN form or VA form, and particularly in the case where the liquid crystal cell in the MVA form is in the black display state, the birefringence of the liquid crystal cell seen by the slope can be similarly compensated.

As shown in Fig. 7, in the liquid crystal display device, when two polarizing plates are arranged on the upper and lower sides of the liquid crystal cell, 22a and 22b in the drawing are arranged in the thickness direction retention Rt, which satisfies the above range, and the thickness direction stays Rt. The sum of the two is greater than 140 nm, and preferably 500 nm or less. In this case, when both of the surfaces 22a and 22b are retained in Ro, and the thickness direction is retained by Rt, the productivity of the industrial polarizing plate can be improved. It is particularly preferable that the in-plane retention Ro is greater than 35 nm and is 65 nm or less, and the thickness direction retention Rt is greater than 90 nm and is 180 nm or less, and is suitable for the MVA liquid crystal cell having the constitution shown in FIG.

In the liquid crystal display device, for example, a polarizing plate protective film which is sold, for example, a TAC film having a thickness of 35 to 85 μm and a thickness of 35 to 85 μm in the thickness direction of Rt=20 to 50 nm is retained in the surface, for example, as shown in FIG. In the position of 22b, the polarizing film can be disposed on the other polarizing plate. For example, the retardation film disposed in 22a of FIG. 7 can be used in which the in-plane retention Ro is larger than 30 nm and is 95 nm or less, and the thickness direction is retained. Rt is larger than 140 nm and is 400 nm or less. This improves the display quality and is also good from the production side of the film.

According to the present invention, the long-length polarizing plate protective film produced by the melt casting method is composed of cellulose ester as a main component, so that alkalization inherent to the cellulose ester can be utilized to carry out the alkali treatment step. When the resin constituting the polarizer is a polyvinyl alcohol, it can be bonded to the polarizing plate protective film using a completely alkalized polyvinyl alcohol aqueous solution in the same manner as the polarizing plate protective film in the past. Therefore, the present invention is excellent in application to the polarizing plate processing method in the past, and is particularly excellent in that a long-sized roller polarizing plate can be obtained.

The manufacturing effect obtained by the present invention is particularly remarkable in the case of a long-length roll of 100 m or more, and the manufacturing effect of the polarizing plate production can be obtained when the length is 1500 m, 2500 m, or 5000 m.

For example, in the manufacture of a polarizing plate protective film, the roll length is 10 to 5000 m, preferably 50 to 4,500 m in consideration of productivity and transportability, and the film width at this time may be selected from the width of the polarizer or the width of the manufacturing process. . The film is produced at a width of 0.5 to 4.0 m, preferably 0.6 to 3.0 m, and can be supplied to a polarizing plate after being wound into a roll shape, and a film of a multiple width or more for the purpose of being wound and wound up on a roll, which is obtained after being cut. The purpose is to use a wide roll, which can be used for polarizing plate processing.

When the polarizing plate protective film is manufactured, a functional layer such as an antistatic layer, a cured film layer, a slippery layer, an adhesive layer, an antiglare layer, and a barrier layer may be applied before and/or after stretching. At this time, various surface treatments such as corona discharge treatment, plasma treatment, and chemical liquid treatment can be carried out as necessary.

In the film forming step, the holding portion of the press plate at both ends of the cut film may be reused as a film material of the same variety or a film of a different type after being pulverized as described above or granulated as necessary. raw material.

Further, the composition containing the cellulose ester having a different concentration of additives such as the plasticizer, the ultraviolet absorber, and the matting agent may be subjected to co-extrusion, or may be an optical film having a laminated structure. For example, an optical film such as a skin layer/core layer/skin layer can be produced. For example, the matting agent can be placed in a large amount in the skin layer or only in the skin layer. The amount of the plasticizer and the ultraviolet absorber to be placed may be placed in a larger amount in the core layer than in the skin layer, or may be placed only in the core layer. Further, the core layer and the skin layer may be changed by a type of a plasticizer or an ultraviolet absorber. For example, a low-volatility plasticizer and/or a UV absorber may be contained in the skin layer, and a plasticizer excellent in plasticity or ultraviolet absorption may be added to the core layer. Excellent UV absorber. The glass transition temperature of the skin layer and the core layer may be different, and the glass transition temperature of the core layer is preferably lower than the glass transition temperature of the skin layer. At this time, the glass transition temperatures of both the skin and the core were measured, and the average value calculated by the volume fractions was defined as the above-mentioned glass transition temperature Tg. Moreover, the viscosity of the melt containing the melt-flowing cellulose ester may be different between the skin layer and the core layer, the viscosity of the skin layer > the viscosity of the core layer, or the viscosity of the core layer, and the viscosity of the skin layer may also be .

The dimensional stability of the optical film of the present invention is such that when the film size after leaving at 23 ° C for 5 hours at 23 ° C, the dimensional change value of 80 ° C 90% RH is less than ± 2.0%, preferably less than 1.0%. More preferably, it is less than 0.5%.

When the optical film of the present invention is used as a protective film for a polarizing plate of a retardation film, if the retardation film itself has a variation within the above range, the absolute value and the orientation angle of the retention property of the polarizing plate are not different from the original setting. It is preferable that the display quality improvement performance is not reduced or the display quality is deteriorated.

Polarizer

When the optical film of the present invention is used as a polarizing plate protective film, the method for producing the polarizing plate is not particularly limited, and it can be produced by a general method. The inner side of the optical film of the present invention is alkalized, and the treated optical film is immersed in at least one surface of the polarizing film formed by stretching in an iodine solution, and it is preferred to use a fully alkalized polyvinyl alcohol aqueous solution for lamination. The optical film of the present invention may be used on the other side, or a polarizing plate may be used to protect the film. For the optical film of the present invention, a polarizing plate protective film used on the other side can be used as a commercially available optical film. For example, as the optical film to be sold, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC4FR-1, KC8UY-HA, and KC8UX-RHA (above, Konicaminolta) are mentioned. Wait. Alternatively, it is preferable to use a polarizing plate protective film which is an optical compensation film of an optical heterogeneous layer formed by orienting a liquid crystal compound such as a discotic liquid crystal, a rod-like liquid crystal or a cholesteric liquid crystal. For example, an optical anisotropic layer can be formed by the method described in JP-A-2003-98348. By using the optical film of the present invention, a polarizing plate having excellent planarity and a stable viewing angle expansion effect can be obtained. A film such as a cyclic olefin resin other than an optical film having a cellulose ester, an acrylic resin, a polyester, or a polycarbonate may be used as the polarizing plate protective film on the other side.

In place of the above-described alkali treatment, it is possible to carry out a polarizing plate processing which is easy to process as described in JP-A-6-94915 and JP-A-6-118232.

The polarizer which is a component mainly composed of a polarizing plate is a light element which passes only a polarizing surface in a certain direction, and a representative polarizer which is now known is a polyvinyl alcohol-based polarizing film, which is a polyvinyl alcohol. The film is obtained by dyeing iodine with those obtained by dyeing with a dichroic dye. The polarizer is preferably formed by subjecting a polyvinyl alcohol aqueous solution to film formation, stretching it after one-axis stretching, or dyeing and then performing one-axis stretching, preferably after treatment with a boron compound. The film thickness of the polarizer is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm. On the polarizing surface, a polarizing plate is formed by laminating the surface of the optical film of the present invention. It is preferably bonded by a water-based adhesive containing a fully alkalized polyvinyl alcohol or the like as a main component.

The polarizer extends in the direction of one axis (usually in the long direction). Therefore, when the polarizing plate is placed in a high-temperature and high-humidity environment, the extending direction (usually the long direction) is tightened, and the direction is perpendicular to the extending direction (usually the width direction). )extend. The thinner the film thickness of the polarizing plate protective film, the larger the expansion ratio of the polarizing plate, and the larger the amount of shrinkage in the extending direction of the polarizer. In general, the direction in which the polarizer is extended is bonded to the casting direction (MD direction) of the film for polarizing plate protection. Therefore, when the film for polarizing plate protection is formed into a film, the expansion ratio in the casting direction is particularly important. The optical film of the present invention has excellent dimensional stability and can be suitably used as such a polarizing plate protective film.

That is, the wave-like spots are not increased by the durability test under the conditions of 60 ° C and 90% RH, and even if the polarizing plate having the optical compensation film on the back side is provided, the viewing angle characteristics after the durability test are not provided. Good recognition of changes.

The polarizing plate is composed of a polarizing film and a protective film for protecting both sides thereof, and a protective film is laminated on the opposite side of the polarizing plate on the opposite side. The protective film and the release film are used for the purpose of protecting the polarizing plate during inspection of the product when the polarizing plate is shipped. At this time, the protective film is bonded for the purpose of protecting the surface of the polarizing plate, and is used to bond the polarizing plate to the reverse surface of the surface of the liquid crystal panel. Further, the release film is used for the purpose of covering the adhesive layer attached to the liquid crystal panel, and is used for bonding the polarizing plate to the surface of the liquid crystal cell.

"Liquid Crystal Display Device"

When a polarizing plate containing a polarizing plate protective film (including a phase difference film) containing the optical film of the present invention is used, it can exhibit higher display quality than a general polarizing plate, and is particularly a wide viewing angle liquid crystal display device, preferably A wide viewing angle liquid crystal display device by a birefringent form is applicable.

The polarizing plate of the present invention can be a MVA (Multi-domein Vertical Alignment) type, a PVA (Patterned Vertical Alignment) type, a CPA (Continuous Pinwheel Alignment) type, an OCB (Optical Compensated Bend) type, an IPS (In Place Switching) type, or the like. It is not limited to a specific liquid crystal type or a polarizing plate configuration.

The liquid crystal display device can be applied as a device for colorization and animation display, and the present invention can improve display quality, improve contrast improvement or resistance of a polarizing plate, and can exhibit real moving image display without fatigue.

In the liquid crystal display device using the polarizing plate containing the retardation film, the polarizing plate used as the retardation film of the present invention is disposed one on the liquid crystal cell or two on both sides of the liquid crystal cell. At this time, when the phase difference film side of the polarizing plate is faced to face the liquid crystal cell of the liquid crystal display device, the display quality can be improved. In Fig. 7, the films of 22a and 22b are liquid crystal cells facing the liquid crystal display device.

In such a configuration, the optical film of the present invention can optically compensate the liquid crystal cell. When the polarizing plate of the present invention is used in a liquid crystal display device, at least one polarizing plate in the polarizing plate of the liquid crystal display device may be used as the polarizing plate of the present invention. By using the polarizing plate of the present invention, high display quality can be provided, and a liquid crystal display device having excellent viewing angle characteristics can be provided.

In the polarizing plate of the present invention, a polarizing plate protective film of a cellulose derivative is used on the surface opposite to the optical film of the present invention as seen by a polarizer, and a general-purpose TAC film or the like can be used. The polarizing plate protective film positioned far from the liquid crystal cell may be provided with other functional layers in order to improve the quality of the display device. For example, a film containing a functional layer such as reflection prevention, anti-glare, scratch resistance, adhesion prevention, and brightness enhancement as a constituent may be bonded to the surface of the polarizing plate of the present invention.

[Examples]

The present invention will be specifically described below by way of examples, but the embodiment of the present invention is not limited thereto.

Example 1 [Production of optical film having cellulose ester (hereinafter simply referred to as cellulose ester film) 1]

The cellulose ester film 1 was produced by a melt casting method using cellulose ester and various additives as described below.

Cellulose ester C-1 (refer to the following) 100 parts by mass

PETB (refer to the following) 8.0 parts by mass

As the compound of the general formula (1) used in the present invention,

Exemplary compound 1-31 (refer to the foregoing) 0.10 parts by mass

TINUVIN928 (manufactured by Ciba Japan Co., Ltd.) 1.5 parts by mass

The cellulose ester was dried at 70 ° C under reduced pressure for 3 hours, and after cooling to room temperature, the above additives were mixed.

The above mixture was pulverized by melt-mixing at 230 ° C using a 2-axis extruder. Further, the glass had a glass transition temperature Tg of 136 °C.

The pellet was melted at 250 ° C in a nitrogen atmosphere, and the self-casting mold 4 was extruded on the first cooling roll 5, and the film was rolled and formed between the first cooling roll 5 and the contact roll 6. In addition, 0.5 parts by mass of cerium oxide particles AEROSIL 200V (manufactured by AEROSIL Co., Ltd.) was added as a lubricant to the hopper opening portion in the middle portion of the extruder 1.

The interval width of the casting mold 4 is 0.5 mm within 30 mm from the end portion in the film width direction, and the heating bolt is adjusted to 1 mm in other places. As the contact roll, a contact roll A was used, and the inside thereof was poured into water of 80 ° C of cooling water.

The position P1 from the position P1 where the resin extruded from the casting die 4 is in contact with the first cooling roll 5 to the upstream end position P2 in the rotational direction of the first cooling roll 5 of the first cooling roll 5 and the contact roll 6 (nip) The length L of the circumferential surface of the first cooling drum 5 is set to 20 mm. Thereafter, the contact roller 6 is peeled off from the first cooling roll 5, and the temperature T of the molten portion before the nip of the first cooling roll 5 and the contact roll 6 is measured is measured. In the present embodiment, the temperature T of the melting portion before the nip of the first cooling roller 5 and the contact roller 6 is set by the upstream side of the nip upstream end P2 by 1 mm. The thermometer (HA-200E manufactured by Anritsu Co., Ltd.) was measured. The measurement result of this example was that the temperature T was 141 °C. The line pressure of the touch roll 6 with respect to the first cooling roll 5 was 14.7 N/cm. And introduced into the tenter, and extended 1.3 times in the width direction at 160 ° C, then cooled to 30 ° C while 3% relaxation in the width direction, and then the self-pressing plate was opened, and the plate holding portion was cut off and applied to both ends of the film. The width is 10 mm and the height is 5 μm to the mark processing, the winding tension is 220 N/m, and the core winding is performed at a taper degree of 40%. Further, the film was adjusted to have an extrusion amount and a drawing speed to a thickness of 80 μm, and the finished film was formed to have a width of 1430 mm and wound up. The core has a size of 152 mm, an outer diameter of 165 to 180 mm, and a length of 1550 mm. As the core material, a pre-stained resin in which an epoxy resin is immersed in glass fibers or carbon fibers is used. An epoxy-based conductive resin was applied to the surface of the core, and the surface was polished to have a surface roughness Ra of 0.3 μm. Moreover, the roll length is 2500 m. The film original sample of the present invention was used as the cellulose ester film 1.

[Production of cellulose ester film 2 to 15]

In the production of the cellulose ester film 1, the cellulose ester film 2 to 15 was produced in the same manner except that the type of the cellulose ester and the compound of the general formula (1) of the present invention were changed as shown in Table 1. Further, the amount of the cellulose ester substituted for the cellulose ester C-1 to be used is the same as that of the cellulose ester C-1, and the amount of the compound represented by the general formula (1) used in the present invention is shown in Table 1. The mass parts stated.

C-1: cellulose acetate propionate (acetylation degree 1.4, propylene substitution degree 1.3, molecular weight Mn = 86,000, Mw / Mn = 2.5)

C-2: cellulose acetate propionate (acetic acid substitution degree 1.3, propyl ketone substitution degree 1.2, molecular weight Mn = 66,000, Mw / Mn = 3.0)

C-3: cellulose acetate propionate (acetamyl substitution degree 1.6, propyl ketone substitution degree 1.2, molecular weight Mn=79,000, Mw/Mn=2.9)

C-4: cellulose acetate propionate (acetamyl substitution degree 2.0, propyl ketone substitution degree 0.7, molecular weight Mn=91,000, Mw/Mn=2.4)

[Production of cellulose ester film 1-1 to 1-20]

In the production of the cellulose ester film 1, the cellulose ester film 1-1 to 1-20 was produced in the same manner as in the production of the cellulose ester film 1 except that the extrusion amount and the drawing speed were adjusted to a film thickness of 40 μm.

Further, the type of the cellulose ester to be used is the same as the type described in Table 1-1, and the amount of addition is the same as that of the cellulose ester C-1, and the compound of the general formula (1) used in the present invention is further used. The type and amount of addition are as shown in Table 1-1 and the parts by mass.

Example 2

[Production of optical film having cellulose ester (hereinafter simply referred to as cellulose ester film) 21]

The cellulose ester film 21 was produced by melt casting using a cellulose ester and various additives as described below.

Cellulose ester C-1 (refer to the above) 100 parts by mass

PETB (refer to the above) 8.0 parts by mass

TINUVIN928 (manufactured by Ciba Japan Co., Ltd.) 1.5 parts by mass

As a compound represented by the general formula (1) used in the present invention, exemplified as a compound 1-31 (refer to the above), 0.25 parts by mass

Q-1: IRGANOX1010 (manufactured by Ciba Japan Co., Ltd.) 0.25 parts by mass

Q-2: SumilizerGS (manufactured by Sumitomo Chemical Co., Ltd.) 0.25 parts by mass

Q-3: GSY-P101 (manufactured by Dai Chemical Industry Co., Ltd.) 0.20 parts by mass

After the cellulose ester was dried at 70 ° C for 3 hours under reduced pressure and cooled to room temperature, the above additives were mixed.

The above mixture was melt-mixed into pellets at 230 ° C using a 2-axis extruder. Further, the glass had a glass transition temperature Tg of 136 °C.

The pellet was melted at 250 ° C in a nitrogen atmosphere, and the cast film 4 was extruded from the first cooling roll 5, and the film was formed by rolling a film between the first cooling roll 5 and the contact roll 6. In addition, 0.5 part by mass of cerium oxide particles Aerosil 200V (manufactured by Nippon Aerosil Co., Ltd.) was added as a lubricant to the hopper opening of the intermediate portion of the extruder 1 .

The interval width between the heating bolt and the casting mold 4 was adjusted to be 0.5 mm from the end portion of the film width direction of 30 mm, and the others were 1 mm. As the contact roll, a contact roll A was used, and the inside thereof was poured into cooling water of 80 °C.

The edge from the position P1 where the resin extruded from the casting die 4 is in contact with the first cooling roll 5 to the first cooling roller 5 which is in contact with the nip of the first cooling roll 5 is increased by the upstream end position P2. The length L of the circumferential surface of the first cooling drum 5 was set to 20 mm. Thereafter, the contact roller 6 is peeled off from the first cooling roll 5, and the temperature T of the molten portion before the nip of the first cooling roll 5 and the contact roll 6 is measured is measured. In the present embodiment, the temperature T of the melting portion before the nip of the first cooling roller 5 and the contact roller 6 is set by the upstream side of the nip upstream end P2 by 1 mm. The thermometer (HA-200E manufactured by Anritsu Co., Ltd.) was measured. The measurement result of this example was that the temperature T was 141 °C. The contact roller 6 was introduced into the tenter at a line pressure of 14.7 N/cm with respect to the first cooling roll 5, and was stretched 1.3 times in the width direction at 160 ° C, and then cooled to 30 ° C while being 3% relaxed in the width direction. Thereafter, the self-pressing plate is opened, the pressing portion of the pressing plate is cut, and a mark of a width of 10 mm and a height of 5 μm is applied to both ends of the film, the winding tension is 220 N/m, and the core winding is performed at a taper degree of 40%. Further, the film was adjusted to have an extrusion amount and a drawing speed to a thickness of 80 μm so that the finished film had a width of 1430 mm and was taken up. The core has a size of 152 mm, an outer diameter of 165 to 180 mm, and a length of 1550 mm. As the core material, a pre-stained resin in which an epoxy resin is immersed in glass fibers or carbon fibers is used. An epoxy-based conductive resin was applied to the surface of the core, and the surface was polished to have a surface roughness Ra of 0.3 μm. Moreover, the roll length is 2500 m. The film original roll sample of the present invention was used as the cellulose ester film 21.

[Production of cellulose ester film 22 to 35]

In the production of the cellulose ester film 21, the type of the cellulose ester, the compound of the general formula (1) of the present invention, and other additives were changed to those shown in Table 2, and the cellulose ester films 22 to 35 were produced in the same manner. . Further, the cellulose ester of the cellulose ester C-1 to be used is added in the same amount as the cellulose ester C-1, and is used in the compound of the general formula (1) of the present invention, and other additives. The types and addition amounts are the mass parts as shown in Table 2.

The obtained cellulose ester film raw roll sample was evaluated by the following method. The results of the evaluation are shown in Table 1, Table 1-1, and Table 2. Further, a part of the cellulose ester film was cut out from the original roll sample, and leakage and evaluation of the haze value were carried out in the following manner.

(horseback failure, core transfer)

The wound cellulose ester film original roll sample is double-coated with a polyethylene film, and stored under the conditions of 25 ° C and 50% RH as shown in a), b), and c) of FIG. Save for 30 days. Thereafter, the box was taken out, and the polyethylene sheet was opened, and the surface of the original film of the film was lighted and reflected by the fluorescent tube, and the deformation or slight disorder was observed, and the horseback failure was given a level according to the following level.

A: I saw the fluorescent light in a straight line.

B: I saw some fluorescent lights appear curved

C: I saw the fluorescent light reflecting the spots.

Further, the film original roll sample after winding and holding is subjected to a dot-shaped deformation of 50 μm or more, or a belt-shaped deformation in a wide direction, and the core transfer is clearly observed, and the transfer of the core from the core portion is measured. m, and classified according to the following levels.

A: The core part is less than 15m

B: The self-winding core part is less than 15~30m

C: The core part of the core is less than 30~50m

D: The core part is 50m or more

(The volume begins to die)

When the winding core is wound up to take up the original roll film, when the roll starts to be broken, the original roll film is taken out from the winding core, and the winding operation is performed again. Calculate the number of defects at this time. This operation was averaged 10 times and averaged according to the following level.

A: 0 or more times, less than 1 time

B: more than 1 time, less than 3 times

C: 3 or more times, less than 5 times

D: 5 or more times

(leakage)

The cellulose ester film was allowed to stand in a high-temperature and high-humidity environment at 80 ° C and 90% RH for 1000 hours, and the presence or absence of leakage (crystallization precipitation) on the surface of the cellulose ester film was visually observed, and evaluated according to the following criteria.

A: No leakage on the surface

B: Leakage on the surface

C: only a slight partial leakage on the surface

D: There is a clear leak on the surface.

(haze value)

The measurement results were carried out by using a haze value meter (Model 1001DP, manufactured by Nippon Denshoku Industries Co., Ltd.), and converted to a haze value at a sample thickness of 80 μm, and evaluated according to the following criteria.

A: The fog value is less than 0.5%

B: fog value is 0.5 to less than 1.0%

C: fog value is 1.0 to less than 1.5%

D: the haze value is 1.5% or more

From Table 1, Table 1-1, and Table 2, the cellulose ester film raw materials 1 to 10, 1-1 to 1-20, and 21 to 30 containing the compound of the above general formula (1) related to the present invention are contained. For the cellulose ester film raw materials 11 to 15, 31 to 35 of the comparative example, it is known that there are few horseback failures, core transfer, and the original film roll of the winding start even if stored for a long period of time. The cellulose ester film is more difficult to produce due to deformation failure. Further, the cellulose ester film cut out from the original roll itself has excellent leakage and haze characteristics for the comparative example.

Example 3

The following composition was prepared.

(antistatic layer coating composition (1))

Polymethyl methacrylate (weight average molecular weight: 550,000, Tg: 90 ° C) 0.5 parts by mass

Propylene glycol monomethyl ether 60 parts by mass

Methyl ethyl ketone 16 parts by mass

Ethyl lactate 5 parts by mass

Methanol 8 parts by mass

Conductive polymer resin P-1 (0.1 to 0.3 μm particles) 0.5 parts by mass

(hard coating layer coating composition (2))

Dipentaerythritol hexaacrylate monomer 60 parts by mass

Dipentaerythritol hexaacrylate 2 polymer 20 parts by mass

Dipentaerythritol hexaacrylate 3-mer component or more 20 parts by mass

Diethoxybenzophenone photoreaction starter 6 parts by mass

Oxantane surfactant 1 part by mass

Propylene glycol monomethyl ether 75 parts by mass

Methyl ethyl ketone 75 parts by mass

(bending prevention layer coating composition (3))

Acetone 35 parts by mass

Ethyl acetate 45 parts by mass

Isopropyl alcohol 5 parts by mass

Diethyl hydrazine cellulose 0.5 parts by mass

Ultrafine particle cerium dioxide 2% acetone dispersion (AEROSIL: 200V, manufactured by Japan AEROSIL Co., Ltd.) 0.1 parts by mass

As described below, a polarizing plate protective film imparting a function is produced.

(Polarizer protective film)

The cellulose ester film original roll sample 1 of the present invention prepared in Example 1 was double-coated with a polyethylene sheet, and stored at 25 ° C, 50% RH for 30 days under the storage method shown in FIG. Thereafter, it was stored at 40 ° C under conditions of 80% RH. Thereafter, each polyethylene sheet was removed, and the bending prevention layer coating composition (3) was gravure-printed to a wet film thickness of 13 μm on a single surface of the cellulose ester film wound from each of the original roll samples at a drying temperature of 80°. Drying is carried out at ±5 °C. This was taken as sample 1A.

On the other side of the cellulose ester film, the antistatic layer coating composition (1) was applied at a film transport speed of 30 m/min at a film width of 1 m at 28 ° C and 82% RH. The film thickness was 7 μm, followed by drying in a dried portion set at 80 ± 5 ° C, and a resin layer having a dried film thickness of about 0.2 μm was provided to obtain a cellulose ester film having an antistatic layer. This was taken as sample 1B. Further, the hard coating layer coating composition (2) was applied onto the antistatic layer to a wet film thickness of 13 μm, dried at a drying temperature of 90 ° C, and then irradiated with ultraviolet rays of 150 mJ/m ² to provide a dry film thickness of 5 μm. Transparent hard coating layer. This was taken as sample 1C.

The obtained cellulose ester film sample 1A, sample 1B, and sample 1C of the present invention have no brush marks and no cracks after drying, and are excellent in coatability.

The cellulose ester film raw material sample 1 was replaced with the cellulose ester film raw material samples 2 to 10, 1-1 to 1-20, and 21 to 30 of the present invention produced in Examples 1 and 2, in the same manner. Coating is carried out. The results were all confirmed to be good coatability.

For comparison, the same methods as described above were carried out for each of the comparative cellulose ester film raw materials 11 to 15, 31 to 35 produced in Examples 1 and 2.

Each of the coating-preventing layer-coated composition (3) was used as the samples 11 to 15A and 31 to 35A, and the antistatic layer-coated composition (1) was applied as the samples 11 to 15B and 31 to 35B. The hard coating layer coating composition (2) was applied to the antistatic layer as samples 11 to 15C and 31 to 35C.

As a result, when coating was performed in a high-humidity environment, brush marks were formed in the samples 11 to 15A and 31 to 35A. Further, the samples 11 to 15B and 31 to 35B were finely cracked after drying, and the samples 11 to 15 C and 31 to 35 C were clearly finely cracked after drying.

Example 4 (production and evaluation of polarizing plates)

A polyvinyl alcohol film having a thickness of 120 μm was immersed in an aqueous solution containing 1 part by mass of iodine, 2 parts by mass of potassium iodide, and 4 parts by mass of boric acid, and extended at 4 times at 50° C. to prepare a polarizer.

The cellulose ester film original samples 1 to 10, 1-1 to 1-20, 21 to 30 of the present invention produced in Examples 1 and 2 and the comparative cellulose ester film original samples 11 to 15, 31 to 35 was wrapped in a double layer of polyethylene foil, stored in a storage method as shown in Fig. 8, and stored at 25 ° C, 50% RH for 30 days, and then stored at 40 ° C, 80% RH. Thereafter, each polyethylene sheet was removed, and the cellulose ester film which was taken up from each raw roll sample was subjected to alkali treatment for 60 seconds in a 2.5 mol/L sodium hydroxide aqueous solution at 40 ° C, and then washed with water to dry the surface, followed by alkali treatment.

On the both sides of the polarizer, the alkali-treated surfaces of the samples 1 to 10, 1-1 to 1-20, 21 to 30 of the present invention and the comparative samples 11 to 15 and 31 to 35 were subjected to complete alkalization. The 5% aqueous solution of vinyl alcohol is bonded to both surfaces as an adhesive to produce polarizing plates PL-1 to PL-10, PL-1-1 to PL-1-20, and PL-21 to PL of the present invention which form a protective film. -30 and the comparative polarizing plates PL-11 to PL-15 and PL-31 to PL-35 were evaluated for planarity.

(As a characteristic evaluation of a liquid crystal display device)

The polarizing plate of the 32-type television AQ-32AD5 manufactured by Sharp Corporation of the VA type liquid crystal display device was peeled off, and each of the polarizing plates produced above was cut in accordance with the liquid crystal cell size.

Two types of polarizing plates prepared as described above were placed under the polarizing axis of the polarizing plate and directly bonded to each other to form a 32-type VA type color liquid crystal display, and the characteristics of the polarizing plate as an optical film were evaluated.

<planarity>

The obtained polarizing plate was cut into an A4 size, and the both ends of the longitudinal direction were attached to the table with a tape on a horizontal table, and the flatness of the surface of the polarizing plate was visually evaluated on the following basis.

A: The surface is completely free of wavy spots.

B: only slightly wavy spots on the surface

C: There are fine wavy spots on the surface

D: There are still large wavy spots on the surface.

(Compared)

The backlight of the liquid crystal television was turned on in an environment of 23 ° C and 55% RH, and after directly standing for 30 minutes, the comparison was visually evaluated according to the following criteria.

A: Black is gathered and distinct

B: Black gathers, but the brightness is slightly lower

C: no aggregation in black, slightly lower sharpness

D: black no aggregation, low brightness

The results are shown in Table 3.

As shown in the above table, the polarizing plates PL-1 to PL-10, PL-1-1 to PL-1-20, and PL-21 to PL-30 of the present invention are comparatively used for the comparative polarizing plates PL-11 to PL-. 15. PL-31 to PL-35 can achieve a remarkable excellent effect of very good polarizing plate characteristics when the protective film having excellent planarity and physical properties is protected on both sides.

Further, from the above table, it is known that the liquid crystal display devices using the polarizing plates PL-1 to PL-10, PL-1-1 to PL-1-20, and PL-21 to PL-30 of the present invention are more polarized than those used. The liquid crystal display devices of the plates PL-11 to PL-15 and PL-31 to PL-35 have high contrast and exhibit excellent display properties. Therefore, it can be used as a polarizing plate for an image display device such as an excellent liquid crystal display.

1. . . Extruder

2. . . filter

3. . . Static mixer

4. . . Cast molding

5. . . Rotating support (first cooling roller)

6. . . Rolling rotor (contact roller)

7. . . Rotating support (second cooling roller)

8. . . Rotating support (third cooling roller)

9. . . Stripping roller

10. . . film

11. . . Transfer roller

12. . . Extension device

13. . . Longitudinal shear

14. . . Embossed ring

15. . . Back roller

16. . . Winding device

21a, 21b. . . Protective film

22a, 22b. . . Phase difference film

23a, 23b. . . Phase axis direction of the film

24a, 24b. . . Polarization direction of the polarizer

25a, 25b. . . Polarized photon

26a, 26b. . . Polarizer

27. . . Liquid crystal cell

29. . . Liquid crystal display device

31. . . Mold body

32. . . Gap

41. . . Metal casing

42. . . Elastic roller

43. . . Metal inner tube

44. . . Elastomer

45. . . Cooling water

51. . . Outer tube

52. . . Inner cylinder

53. . . space

54. . . Coolant

55a, 55b. . . Rotary axis

56a, 56b. . . Outer tube support flange (flange)

60. . . Fluid shaft

61a, 61b. . . Inner cylinder support flange (flange)

62a, 62b. . . Intermediate path

110. . . Core body

117. . . Support board

118. . . shelf

120. . . Cellulose ester film original volume

120. . . Cellulose ester film original volume

Fig. 1 is a schematic flow chart showing an embodiment of an apparatus for carrying out a method for producing an optical film (cellulose ester film) of the present invention.

Fig. 2 is an enlarged flow chart showing an important part of the manufacturing apparatus of Fig. 1.

Fig. 3 (a) is a view showing the appearance of an important portion of the casting mold, and Fig. 3 (b) is a cross-sectional view showing an important portion of the casting mold.

Fig. 4 is a cross-sectional view showing a first embodiment of a rolling rotor.

Fig. 5 is a cross-sectional view showing the rotation axis of the second embodiment of the rolling rotor in a vertical plane.

Fig. 6 is a cross-sectional view showing a plane of a rotating shaft of a second embodiment including a rolling rotor.

Fig. 7 is a schematic exploded perspective view showing a configuration of a liquid crystal display device.

Fig. 8 is a view showing a state of storage of an optical film (cellulose ester film) original roll.

1. . . Extruder

2. . . filter

3. . . Static mixer

4. . . Cast molding

5. . . Rotating support (first cooling roller)

6. . . Rolling rotor (contact roller)

7. . . Rotating support (second cooling roller)

8. . . Rotating support (third cooling roller)

9. . . Stripping roller

10. . . film

11. . . Transfer roller

12. . . Extension device

13. . . Longitudinal shear

14. . . Embossed ring

15. . . Back roller

16. . . Winding device

F. . . Optical film (yuan volume)

P1. . . position

P2. . . Upstream

Claims (6)

An optical film characterized by containing at least one of the compounds represented by the following general formula (1) and a cellulose ester; (wherein R ¹ and R ² each independently represent a substituent selected from the group 1 below, R ³ represents a hydrogen atom or an alkyl group, and n represents an integer of 0 to 4; and plural R ¹ may be the same or different) And Group 1 is alkyl, cycloalkyl, aryl, decylamino, alkylthio, arylthio, alkenyl, halogen, alkynyl, heterocyclyl, alkylsulfonyl, aryl Sulfonyl, alkylsulfinyl, arylsulfinyl, phosphonium, fluorenyl, aminomethylhydrazine, amine sulfonyl, sulfonylamino, cyano, alkoxy, aryloxy , heterocyclic oxy, decyloxy, decyloxy, amine carbonyloxy, amine, anilino, imido, ureido, alkoxycarbonylamino, alkoxycarbonyl, aryloxy A carbonyl group, a heterocyclic thio group, a thioureido group, a hydroxy group and a thiol group, but these substituents may be further substituted by the same substituent. The optical film of claim 1, which contains at least one selected from the group consisting of a hindered phenol compound, a phosphorus compound, a lactone compound, and an acrylate compound. A method for manufacturing an optical film, which is characterized by a patent application The optical film of the first or second item is produced by a melt casting method. A polarizing plate characterized by having an optical film according to item 1 or item 2 of the patent application on at least one side of a polarizer. A liquid crystal display device characterized by using a polarizing plate as in claim 4 of the patent application. A compound for an optical film characterized by the following general formula (2); (wherein R ⁴ to R ⁶ each independently represent an alkyl group, a cycloalkyl group or an aryl group, R ⁷ represents a substituent selected from the group 1 below, and n represents an integer of 0 to 3; the plural R ⁷ may be the same Or different), and Group 1 is alkyl, cycloalkyl, aryl, decylamino, alkylthio, arylthio, alkenyl, halogen, alkynyl, heterocyclyl, alkyl sulfonate Mercapto, arylsulfonyl, alkylsulfinyl, arylsulfinyl, phosphinium, fluorenyl, aminomethyl sulfonyl, sulfonyl, sulfonyl, cyano, alkane Oxyl, aryloxy, heterocyclooxy, decyloxy, decyloxy, amine carbonyloxy, amine, anilino, imido, ureido, alkoxycarbonylamino, alkoxycarbonyl And an aryloxycarbonyl group, a heterocyclic thio group, a thioureido group, a hydroxy group and a thiol group, but these substituents may be further substituted by the same substituent.