TWI599601B - Optical film manufacturing method and manufacturing apparatus - Google Patents

Description

Optical film manufacturing method and manufacturing device

The present invention relates to a method for producing an optical film in which an end portion of a long obliquely oriented film in the width direction is cut and a remaining portion is taken as an optical film, and an apparatus for producing the optical film.

The elongated optical film is produced, for example, by a solution casting film forming method or a melt casting film forming method. Both end portions in the width direction of the produced optical film are cut off by the cutting device because the film thickness is not uniform or the shape of the end face is not uniform. For example, in Patent Document 1, a circular upper blade and a circular lower blade are used to cut both end portions of the optical film.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2009-154252 (refer to claim 1, first figure, second figure, etc.)

Further, in recent years, a self-luminous type display device such as an organic EL (Electro-Luminescence) display device which is also called an OLED (Organic Light-Emitting Diode) has been attracting attention. In the OLED, in order to improve the light extraction efficiency, a reflector such as an aluminum plate is provided on the back side of the display. Therefore, light incident on the display is reflected by the reflector, and contrast of the image is lowered.

Therefore, in order to achieve an improvement in the contrast between the light and the dark caused by the reflection of the external light, the stretched film and the polarizing element are bonded to each other to form a circularly polarizing plate, and the circular polarizing plate is disposed on the surface side of the display. Is known. In this case, the circular polarizing plate is formed by bonding a polarizing element and a stretched film so that the in-plane slow axis of the stretched film is inclined at a desired angle with respect to the transmission axis of the polarizing element. .

At this time, as the above-mentioned stretched film, by using an elongated obliquely extending film (also referred to as a long obliquely oriented film) extending in the oblique direction with respect to the longitudinal direction and the width direction, since the long polarizing film and the long polarizing film can be used The strip-shaped oblique alignment film is bonded and manufactured by a roll-to-roll method to produce a circular polarizing plate, so that the productivity of the circular polarizing plate is greatly improved. Therefore, in recent years, the manufacture of such a long oblique alignment film has been actively carried out.

Similarly, in the above-described elongated oblique alignment film, both end portions in the width direction are not evenly formed, and therefore are cut off by the cutting device after the production. However, it has been found that if the both ends of the long oblique alignment film are cut by the conventional cutting device, the remaining after the cutting is completed When the optical film is wound, a slight deviation of the core direction occurs in the end surface of the roll, and the cut optical film is wound while being inclined. Further, it is found that a fibrous foreign matter (hereinafter referred to as "sole") or fluffing is formed in the end portion on one side in the width direction of the optical film (product portion) remaining after the cutting. It is presumed that the reason why the alignment direction of the long oblique alignment film is inclined with respect to the longitudinal direction and the width direction is such that when the long oblique alignment film is cut along the longitudinal direction by the cutting device, The alignment of the elongated oblique alignment film becomes an impedance, and the elongated oblique alignment film is easily deflected toward the alignment direction with respect to the cutting device (upper blade, lower blade), and therefore, the elongated oblique alignment film The cutoff state will deteriorate. If the cut state of the long oblique alignment film is poor, the optical film may be broken at the time of cutting. It is presumed that the tilting of the optical film after the above-described cutting is caused by the fact that the elongated alignment film is ejected in the alignment direction at the time of cutting.

In the above-mentioned Patent Document 1, the cutting of the elongated oblique alignment film is not discussed. It is conceivable that when the object to be cut is a long oblique alignment film, it is impossible to tilt the alignment after the cutting. The occurrence of whiskers or fuzzing at the ends of the optical film and the breaking of the optical film at the time of cutting are suppressed.

The present invention has been made to solve the above problems, and an object of the invention is to provide a film for both ends of an optical film when the optical film is obtained by cutting both ends of the long oblique alignment film. Or a method for producing an optical film and a manufacturing apparatus for suppressing the occurrence of fuzzing and breaking of an optical film at the time of cutting.

The above object of the present invention is achieved by the following method and apparatus for producing an optical film.

In other words, in the method of producing an optical film according to one aspect of the present invention, the end portions in the width direction of the long oblique alignment film are cut by the first cutting portion and the second cutting portion, respectively. In the breaking step, the strip-shaped oblique alignment film is inclined in the direction of the width direction of the film in the width direction, and the portion remaining in the strip-shaped oblique alignment film after cutting the both end portions is used as an optical film. The first cutting portion and the second cutting portion respectively include a first blade and a second blade, and the first blade is disposed on one side of the film surface of the long oblique alignment film, and the rotating shaft is disposed In the width direction, the second blade is disposed on the other side of the film surface, and the rotation axis is opposite to the aforementioned angle in the film surface at an angle corresponding to a beam angle of the first blade In the cutting step, each of the first cutting portion and the second cutting portion is in the side of the width direction of the first blade and the other side thereof Beam of the first knife The second blade is disposed in a direction in which the angle is increased, and the second blade is disposed on a side where the angle formed by the surface of the second blade forming the toe angle and the direction of the alignment of the long oblique alignment film is small. The first blade and the second blade sandwich and cut the long oblique alignment film.

The apparatus for producing an optical film according to another aspect of the present invention includes a first cutting portion and a second cutting portion that cut both end portions in the width direction of the long oblique alignment film, and the long oblique alignment film The alignment direction in the film surface is inclined with respect to the width direction, and the portion remaining in the long oblique alignment film after the both end portions are cut is an optical film, wherein the first cutting portion and the first portion Each of the cutting portions includes a first blade and a second blade, and the first blade is disposed on one side of the film surface of the long oblique alignment film, and the rotation axis is disposed along the width direction; a knife disposed on the other side of the film surface, wherein the rotation axis is inclined with respect to the width direction at an angle corresponding to a beam angle of the first blade in the film surface, and the first Each of the first cutting portion and the second cutting portion is formed between one side and the other side of the first blade in the width direction of the first cutting portion and the second cutting portion. With the opposite of the front The second blade is inclined in a direction in which the toe angle of the first blade is increased, and is disposed on a side where the angle formed by the surface of the second blade forming the toe angle and the alignment direction of the long oblique alignment film is small. The second knife mentioned above.

According to the above manufacturing method and manufacturing apparatus, since it is wide In the direction of the first blade, the position of the second blade is closer to the direction of the alignment direction of the elongated oblique alignment film with respect to the first blade, and the long oblique alignment film is cut. Therefore, the second blade is second compared to the first blade. When the knives are disposed on the side opposite to the above and cut off, the impedance at the time of cutting due to the alignment of the elongated oblique alignment film can be suppressed. Therefore, at the time of cutting, the long oblique alignment film is relatively difficult to be bounced in the alignment direction with respect to the first cutting portion and the second cutting portion, and the slit oblique alignment film can be lifted. Broken state. As a result, even when the optical film is obtained by cutting both end portions of the long oblique alignment film, it is possible to cause breakage of the optical film at the end of the optical film at the end of the optical film or during the cutting. inhibition.

1‧‧‧ manufacturing equipment

8a‧‧‧1st cut-off

8b‧‧‧2nd cut-off

10a‧‧‧Upper knife (2nd knife)

10a ₁ ‧‧‧Rotary axis

10b‧‧‧Blade (1st knife)

10b ₁ ‧‧‧Rotary axis

F‧‧‧Optical film

F’‧‧‧Long strip oblique alignment film

S‧‧‧ face

Ta‧‧‧ end

Tb‧‧‧ end

Θ‧‧‧ angle

θ 1‧‧‧beam angle

[Fig. 1] is a plan view schematically showing a schematic configuration of an apparatus for manufacturing an optical film according to an embodiment of the present invention.

[Fig. 2] is a plan view schematically showing an example of a rail form of an extension portion provided in the above-described manufacturing apparatus.

[Fig. 3] A perspective view showing a schematic configuration of a film cutting device provided in the above-described manufacturing apparatus.

[Fig. 4] is a plan view of the above film cutting device.

[Fig. 5] is a plan view of a film cutting device of a reference example.

[Fig. 6] Fig. 6 is a cross-sectional view showing a schematic configuration of an organic EL display device as an example of an optical film to be produced by the above-described manufacturing apparatus.

[Fig. 7] Fig. 7 is a cross-sectional view showing a schematic configuration of a liquid crystal display device as another example in which the above optical film is applied.

An embodiment of the present invention will be described below with reference to the drawings. Further, in the present specification, when the numerical range is marked as A to B, it is considered that the value of the lower limit A and the upper limit B is included in the numerical range. Further, the present invention is not limited to the following.

The method for producing an optical film according to the present embodiment includes a cutting step of cutting both end portions in the width direction of the long oblique alignment film by the first cutting portion and the second cutting portion, and the strip The oblique alignment film is inclined in the alignment direction with respect to the width direction in the film surface, and the remaining portion of the long oblique alignment film after the both end portions are cut is used as an optical film. Each of the first cutting portion and the second cutting portion includes a first blade and a second blade, and the first blade is disposed on one side of the film surface of the long oblique alignment film, and the rotating shaft is disposed so that In the width direction, the second blade is disposed on the other side of the film surface, and the rotation axis is opposite to the width in the film surface at an angle corresponding to a beam angle of the first blade. Tilt in direction. In the cutting step, each of the first cutting portion and the second cutting portion is in the one side and the other side in the width direction of the first blade, with respect to the first blade The second blade is inclined in a direction in which the toe angle is increased, before the surface of the second blade forming the toe angle and the long oblique alignment film The second blade is disposed on the side where the angle formed by the alignment direction is reduced, and the long oblique alignment film is sandwiched and cut by the first blade and the second blade.

Moreover, the apparatus for manufacturing an optical film according to the present embodiment includes a first cutting portion and a second cutting portion that cut both end portions in the width direction of the long oblique alignment film, and the long oblique alignment film is The alignment direction of the inside of the film in the width direction is inclined, and the remaining portion of the long oblique alignment film after the both end portions are cut is used as an optical film. Each of the first cutting portion and the second cutting portion includes a first blade and a second blade, and the first blade is disposed on one side of the film surface of the long oblique alignment film, and the rotating shaft is disposed so that The second blade is disposed on the other side of the film surface along the width direction, and the rotation axis is opposite to the width in the film surface at an angle corresponding to a beam angle of the first blade. The direction is inclined, and the long oblique alignment film is sandwiched and cut between the first blade and the first blade. Each of the first cutting portion and the second cutting portion increases in a direction toward a toe angle with respect to the first blade in one side and the other side in the width direction of the first blade. The second blade is disposed such that the second blade is inclined, and the angle formed by the surface of the second blade forming the toe angle and the direction of the alignment of the long oblique alignment film is reduced.

Here, the alignment direction of the long oblique alignment film, that is, the direction of the slow axis is in the film surface of the long oblique alignment film (in the plane perpendicular to the thickness direction), and is formed with respect to the width direction of the film. The direction of the angle exceeding 0° below 90° (automatically relative to the length of the film) The direction of the dimension also becomes an angle of more than 0° and less than 90°). Since the retardation axis is usually present in the extending direction or in a direction perpendicular to the extending direction, it can be manufactured by extending at an angle of more than 0° with respect to the width direction of the film of less than 90°. A long obliquely oriented film of a slow phase axis. The angle formed between the width direction of the elongated oblique alignment film and the late phase axis, that is, the alignment angle, can be arbitrarily set to a desired angle within a range of more than 0° and less than 90°.

In the present embodiment, the long strip refers to a length of at least 5 times or more with respect to the width of the film, and preferably has a length of 10 times or more, more specifically, it can be regarded as having a roll. The length (film roll) of the length that is wound into a roll and stored or transported.

In the production of a long oblique alignment film, the film can be formed into a desired length by continuously producing a film. Further, the elongated oblique alignment film may be configured such that after the long film is formed into a film, it is once wound on a winding core to form a wound body, and the long film is supplied from the winding body to the oblique stretching step. In the case of manufacturing, the long film after the film formation may be wound and continuously supplied from the film forming step to the oblique stretching step to be produced. When the film forming step and the tilting step are continuously performed, it is preferable to feed back the film thickness or optical value of the stretched film and change the film forming conditions to obtain a desired long oblique alignment film. .

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. In addition, in the following description, when it is described as a long film, it is the strip shape which becomes an extension object in the inclination extension process. The film is distinguished from the obliquely oriented film which is obliquely extended.

<About long film>

The long film to be stretched in the apparatus for producing an optical film of the present embodiment (details will be described later) is not particularly limited as long as it is a film made of a thermoplastic resin, for example, a film which is stretched. In the case of use for optical use, a film made of a resin having a property of being transparent with respect to a desired wavelength is preferred. Examples of such a resin include a polycarbonate resin, a polyether oxime resin, a polyethylene terephthalate resin, a polyamidene resin, a polymethyl methacrylate resin, and a polyfluorene system. Resin, polyarylate resin, polyethylene resin, polyvinyl chloride resin, olefin polymer resin having an alicyclic structure (alicyclic olefin polymer resin, also referred to simply as cyclic olefin resin), A cellulose ester resin or the like.

Among these, from the viewpoints of transparency, mechanical strength, and the like, a polycarbonate resin, an alicyclic olefin polymer resin, or a cellulose ester resin is preferable. In addition, it is more preferable that the alicyclic olefin polymer-based resin or the cellulose ester-based resin is easy to adjust the phase difference in the case of the optical film. Therefore, the alicyclic olefin polymer resin, the cellulose ester resin, and the polycarbonate resin which are preferably used in the present embodiment will be described below.

[Cycloaliphatic olefin polymer resin]

As an alicyclic olefin polymer resin, it can be used in Japan. The cyclic olefin random multi-component copolymer described in Japanese Laid-Open Patent Publication No. Hei 05-97978, the entire disclosure of which is incorporated herein by reference. A thermoplastic dicyclopentadiene ring-opening polymer, a hydride thereof, or the like.

The alicyclic olefin polymer-based resin is a polymer having an alicyclic structure as a saturated alicyclic hydrocarbon (cycloalkane) structure or an unsaturated alicyclic hydrocarbon (cycloolefin) structure. Although the number of carbon atoms constituting the alicyclic structure is not particularly limited, it is mechanical strength, heat resistance, and long in the range of usually 4 to 30, preferably 5 to 20, more preferably 5 to 15. It is suitable that the film has a high degree of balance in the formability of the film.

The proportion of the repeating unit in which the alicyclic structure is contained in the alicyclic olefin polymer is preferably selected as appropriate, but is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight. %the above. When the ratio of the repeating unit having an alicyclic structure in the alicyclic olefin resin falls within this range, the transparency of the optical material such as the retardation film obtained by the long oblique alignment film of the present embodiment and Heat resistance will improve, so it is better.

Examples of the olefin polymer-based resin having an alicyclic structure include a norbornene-based resin, a monocyclic cyclic olefin-based resin, a cyclic conjugated diene-based resin, a vinyl alicyclic hydrocarbon-based resin, and the like. Hydride, etc. Among these, the norbornene-based resin is preferably used because it has good transparency and moldability.

Examples of the norbornene-based resin include a ring-opening polymer having a monomer having a norbornene structure or a monomer having a norbornene structure and a monomeric ring-opening copolymer or such a hydride, an addition polymer of a monomer having a norbornene structure or an addition copolymer of a monomer having a norbornene structure and other monomers or the like Hydride, etc. Among these, a ring-opened (co)polymer hydride having a monomer having a norbornene structure, from the viewpoints of transparency, formability, heat resistance, low hygroscopicity, dimensional stability, and lightness, It is particularly suitable for use.

As a method of forming a long film using a norbornene-based resin as described above, a method of producing a solution casting method (solution film forming method) or a melt casting method (for example, melt-bending method) described later is preferable. . The melt extrusion method is exemplified by the use of a mold expansion method, and is preferably a method using a T mold from the viewpoint of excellent productivity and thickness precision.

As a method of using a T-die, the thermoplastic resin which is in a molten state when it is adhered to a cooling cylinder is kept in a stable state as described in Japanese Laid-Open Patent Publication No. 2004-233604. To produce a small strip of film with a staggered optical characteristic such as retardation or alignment angle.

Specifically, when a long film is produced by a melt extrusion method, the sheet-like thermoplastic resin extruded from the mold is adhered to the cooling cylinder under a pressure of 50 kPa or less and pulled. Method 2) When a long film is produced by a melt extrusion method, the range from the opening portion of the mold to the first cooling cylinder is covered by the surrounding member, and will be from the surrounding member to the mold. a method in which the distance from the opening or the first cooling cylinder is set to 100 mm or less; and 3) when the long film is produced by the melt extrusion method, the distance is pushed out from the opening of the mold. a method of heating the temperature of the sheet-like thermoplastic resin to a specific temperature within a temperature of 10 mm; 4) satisfying the relationship so that the sheet-like thermoplastic resin extruded from the mold is adhered to the cooling cylinder under a pressure of 50 kPa or less When the long film is produced by the melt extrusion method, the sheet-like thermoplastic resin extruded from the opening of the mold is blown with the drawing speed of the initially sealed cooling cylinder. A method in which the speed difference between the winds is less than 0.2 m/s.

The long film may be a single layer or a laminated film of two or more layers. The laminated film can be obtained by a well-known method such as a co-extrusion molding method, a co-cast molding method, a film lamination method, or a coating method. Among these, a co-extrusion molding method and a co-cast molding method are preferred.

[Cellulose ester resin]

The cellulose ester-based resin film is a compound containing a cellulose halide satisfying the following formulas (1) and (2) and containing a compound represented by the following general formula (A).

Equation (1) 2.0≦Z1<3.0

Formula (2) 0≦X<3.0 (In the formulae (1) and (2), Z1 represents the total thiol substitution degree of the cellulose oxime, and X represents the propylene group substitution degree of the cellulose ruthenium and the butyl group The sum of the degrees of substitution).

Hereinafter, the general formula (A) will be described in detail. In the general formula (A), each of L ₁ and L ₂ independently represents a single bond or a divalent linking group. Examples of L ₁ and L ₂ include the following structures. (The following R represents a hydrogen atom or a substituent).

As L ₁ and L ₂ , -O-, -COO-, -OCO- are preferable.

R ₁ , R ₂ and R ₃ each independently represent a substituent. Specific examples of the substituent represented by R ₁ , R ₂ and R ₃ include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), and an alkyl group (methyl group, ethyl group, n- group). Propyl, isopropyl, tert-butyl, n-octyl, 2-ethylhexyl, etc.), cycloalkyl (cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl, etc.), alkene (vinyl, allyl, etc.), cycloalkenyl (2-cyclopenten-1-yl, 2-cyclohexen-1-yl, etc.), alkynyl (ethynyl, propargyl, etc.), aromatic (phenyl, p-tolyl, naphthyl, etc.), heterocyclic (2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl, etc.), cyano, hydroxy, nitro , a carboxyl group, an alkoxy group (methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group, etc.), an aryloxy group (phenoxy group, 2-methylphenoxy, 4-tert-butylphenoxy, 3-nitrophenoxy, 2-tetradecylaminophenoxy, etc., decyloxy (methyloxyl, acetamidine) Oxyl, pivaloyloxy, stearyloxy, benzhydryloxy, p-methoxyphenylcarbonyloxy, etc., amine group (amine group, methylamino group, dimethyl group) Amine, anilino, N -Methyl-anilino, diphenylamino, etc.), mercaptoamine (carbomethylamino, ethionylamino, neopentylamino, laurylamine, benzhydrylamine Base, etc., alkyl and arylsulfonylamino (methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonate Mercaptoamine, p-methylphenylsulfonylamino, etc., mercapto, alkylthio (methylthio, ethylthio, n-hexadecanethio, etc.), arylthio (phenylthio) , p-chlorophenylthio, m-methoxyphenylthio, etc.), amidoxime (N-ethylaminesulfonyl, N-(3-dodecyloxypropyl)aminesulfonyl, N , N-dimethylamine sulfonyl, N-acetyl sulfonyl sulfonyl, N-benzhydryl sulfonyl sulfonyl, N-(N' phenyl carbamoyl) sulfonyl sulfhydryl, etc.) , sulfo, fluorenyl (ethylidene, neopentyl benzoyl thiol, etc.), amine methyl sulfhydryl (amine methyl sulfhydryl, N-methyl carbamoyl, N, N-dimethylamine Anthracenyl, N,N-di-n-octylaminecarbamyl, N-(methylsulfonyl)amine, mercapto, etc.).

R ₁ and R _{2 are} preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted cyclohexyl group, more preferably a substituted phenyl group, a substituted cyclohexyl group, and even more preferably a 4-position. A phenyl group having a substituent and a cyclohexyl group having a substituent at the 4-position.

R _{3 is} preferably a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, a hydroxyl group, a carboxyl group, an alkoxy group, an aryloxy group, a decyloxy group, a cyano group or an amine group, more preferably It is a hydrogen atom, a halogen atom, an alkyl group, a cyano group, or an alkoxy group.

Wa and Wb are a hydrogen atom or a substituent, but (I) Wa and Wb may be bonded to each other to form a ring; (H) at least one of Wa and Wb may have a ring structure; or (III) Wa and Wb At least one of them may also be an alkenyl or alkynyl group.

Specific examples of the substituent represented by Wa and Wb include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), and an alkyl group (methyl group, ethyl group, n-propyl group, and isopropyl group). Base, tert-butyl, n-octyl, 2-ethylhexyl, etc.), cycloalkyl (cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl, etc.), alkenyl (vinyl, Allyl group, etc., cycloalkenyl (2-cyclopenten-1-yl, 2-cyclohexen-1-yl, etc.), alkynyl (ethynyl, propargyl, etc.), aryl (phenyl, P-tolyl, naphthyl, etc.), heterocyclic group (2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl, etc.), cyano, hydroxy, nitro, carboxyl, alkoxy (methoxy, ethoxy, isopropoxy, tert-butoxy, n-octyloxy, 2-methoxyethoxy, etc.), aryloxy (phenoxy, 2-methylbenzene) Oxyl, 4-tert-butylphenoxy, 3-nitrophenoxy, 2-tetradecylaminophenoxy, etc., decyloxy (methyloxy, ethoxylated, neopentyl) Alkoxy, stearyloxy, benzhydryloxy, p-methoxyphenylcarbonyloxy, etc.), amine group (amine group, methylamine) Base, dimethylamino, anilino, N-methyl-anilino, diphenylamino, etc.), mercaptoamino (carbomethylamino, ethionylamino, neopentylamino) , lauryl mercapto, benzhydrylamino, etc., alkyl and arylsulfonylamino (methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino) , 2,3,5-trichlorophenylsulfonylamino, p-methylphenylsulfonylamino, etc., mercapto, alkylthio (methylthio, ethylthio, n-hexadecane) Sulfur-based, etc., arylthio (phenylthio, p-chlorophenylthio, m-methoxyphenylthio, etc.), aminesulfonyl (N-ethylaminesulfonyl, N-(3-ten) Dialkyloxypropyl)amine fluorenyl, N,N-dimethylamine sulfonyl, N-acetyl sulfonyl sulfonyl, N-benzamide sulfonyl, N-(N'phenyl Aminomethyl) sulfonyl, etc., sulfo, fluorenyl (ethyl fluorenyl, neopentyl benzoyl thiol, etc.), amine carbaryl (amine carbaryl, N-methylamine formazan) Base, N,N-dimethylaminecarbamyl, N,N-di-n-octylaminecarbamyl, N-(methylsulfonyl)amine, mercapto, etc.).

The above substituent may be further substituted with the above groups.

(I) In the case where Wa and Wb are bonded to each other to form a ring, the ring is preferably a nitrogen-containing 5-membered ring or a sulfur-containing 5-membered ring. Further, the general formula (A) is particularly preferably a compound represented by the following general formula (1) or general formula (2).

In the general formula (1), A ₁ and A ₂ each independently represent -O-, -S-, -NRx- (Rx represents a hydrogen atom or a substituent) or -CO-. Examples of the substituent represented by Rx are the same as the specific examples of the substituent represented by the above Wa and Wb. Rx is preferably a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group.

In the general formula (1), the X system represents a non-metal atom of Groups 14 to 16. As X, it is preferably =O, =S, =NRc, and =C(Rd)Re. Here, Rc, Rd, and Re represent a substituent, and the examples are the same as the specific examples of the substituent represented by the above Wa and Wb. _{L 1, L 2, R 1} , R 2, R 3, n, and line (A) of the general formula L _{1, L 2, R 1,} R 2, R 3, n synonymous.

In the general formula (2), Q ₁ represents -O-, -S-, -NRy- (Ry represents a hydrogen atom or a substituent), -CRaRb- (Ra and Rb represent a hydrogen atom or a substituent) or -CO-. Here, Ry, Ra, and Rb represent a substituent, and as an example, they are synonymous with a specific example of the substituent represented by the above-mentioned Wa and Wb.

The Y system represents a substituent. The example of the substituent represented by Y is synonymous with the specific example of the substituent represented by the above-mentioned Wa and Wb. Y is preferably an aryl group, a heterocyclic group, an alkenyl group or an alkynyl group.

The aryl group represented by Y may, for example, be a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group or a biphenyl group, and is preferably a phenyl group or a naphthyl group, more preferably a phenyl group.

Examples of the heterocyclic group include a heterocyclic group containing at least one hetero atom such as a nitrogen atom, an oxygen atom or a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group or a benzothiazolyl group. Preferably, it is a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group or a thiazolyl group.

These aryl or heterocyclic groups may also have at least one substitution base. Examples of the substituent include a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 6 carbon atoms, and an alkylsulfonyl group having 1 to 6 carbon atoms. , carboxyl group, fluoroalkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, alkylthio group having 1 to 6 carbon atoms, N-alkylamino group having 1 to 6 carbon atoms, carbon number 2~ 12 N,N-dialkylamino group, N-alkylamine sulfonyl group having 1 to 6 carbon atoms, N,N-dialkylamine sulfonyl group having 2 to 12 carbon atoms, and the like.

_{L 1, L 2, R 1} , R 2, R 3, n, and line (A) of the general formula L _{1, L 2, R 1,} R 2, R 3, n synonymous.

(II) In the general formula (A), as a specific example in the case where at least one of Wa and Wb has a ring structure, the following general formula (3) is preferable.

In the general formula (3), Q ₃ represents =N- or =CRz- (Rz-based hydrogen atom or a substituent), and Q ₄ represents a non-metal atom of Groups 14 to 16. The Z system represents a non-metal atom group which forms a ring together with Q ₃ and Q ₄ .

The ring formed by Q ₃ , Q ₄ and Z may be further condensed with another ring. The ring formed by Q ₃ , Q ₄ and Z is preferably a nitrogen-containing 5-membered ring or a 6-membered ring which is a benzene ring condensed ring.

_{L 1, L 2, R 1} , R 2, R 3, n, and line (A) of the general formula L _{1, L 2, R 1,} R 2, R 3, n synonymous.

(III) In the case where at least one of Wa and Wb is an alkenyl group or an alkynyl group, these are preferably a vinyl group or an ethynyl group having a substituent.

Among the compounds represented by the above general formula (1), general formula (2) and general formula (3), a compound represented by the general formula (3) is particularly preferred.

The compound represented by the general formula (3) is superior in heat resistance and light resistance to the compound represented by the general formula (1), and is organic to the compound represented by the general formula (2). The solubility of the solvent or the compatibility with the polymer is good.

The compound represented by the general formula (A) may be appropriately adjusted in order to impart desired wavelength dispersibility and anti-bleed property, but the amount of addition is preferably 1 with respect to the cellulose derivative. ~15% by mass, especially including 2 to 10% by mass. Within this range, sufficient cellulose dispersibility and anti-bleed property can be imparted to the above cellulose derivative.

Further, the compounds represented by the general formula (A), the general formula (1), the general formula (2), and the general formula (3) can be obtained by referring to a known method. Specifically, reference can be made to Journal of Chemical Crystallography (1997); 27 (9); 512-526), and Japanese Special Open 2010- The synthesis is carried out in the publication No. 31223 and JP-A-2008-107767.

(About cellulose telluride)

The cellulose halide film of the present embodiment contains cellulose halide as a main component. For example, the cellulose halide film of the present embodiment contains a cellulose halide which is preferably in the range of 60 to 100% by mass based on the total mass (100% by mass) of the film. Further, the total thiol substitution degree of the cellulose oxime is less than 3.0, more preferably from 2.2 to 2.7.

Examples of the cellulose oxime compound include an ester of cellulose and an aliphatic carboxylic acid and/or an aromatic carboxylic acid having a carbon number of 2 to 22, and particularly an ester of cellulose and a lower fatty acid having a carbon number of 6 or less. good.

The thiol group bonded to the hydroxyl group of the cellulose may be a straight chain, a branch, or a ring. Further, it may be substituted with another substituent. In the case of the same degree of substitution, since the birefringence is lowered if the number of carbon atoms is large, the carbon number is preferably selected among the fluorenyl groups having 2 to 6 carbon atoms, and the degree of substitution of the fluorenyl group and the butyl group. The sum of the degrees of substitution is 0 or more and less than 3.0. Preferably, the cellulose halide has a carbon number of 2 to 4, more preferably 2 to 3.

Specifically, as a cellulose halide such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate or cellulose acetate phthalate An acid ester-like ethyl group, in addition, a mixed fatty acid ester in which a cellulose ester of a propionate group, a butyrate group or a phthalic acid group is bonded can be used. In addition, the butyrate group forming butyrate can be straight Chains can also be branches.

In the present embodiment, cellulose acetate, cellulose acetate butyrate or cellulose acetate propionate is particularly preferably used as the cellulose halide.

Further, the cellulose halide described above preferably satisfies the following formula (i) and formula (ii).

Equation (i) 2.0≦X+Y<3.0

Formula (ii) 0≦X<3.0

In the formula, Y represents the degree of substitution of an ethyl group, and X represents the degree of substitution of a propyl group or a butyl group or a mixture thereof.

Further, in order to obtain an optical property that can achieve the object, a resin having a different degree of substitution may be used in combination. The mixing ratio at this time is preferably 1:99 to 99:1 (mass ratio).

Among the above, cellulose acetate propionate is particularly preferably used as the cellulose halide. In the cellulose acetate propionate, it is preferably 0≦Y≦2.5, and 0.5≦X≦3.0 (but, 2.0≦X+Y<3.0), more preferably 0.5≦Y≦2.0, and 1.0≦. X≦2.0 (but, 2.0≦X+Y<3.0). Further, the degree of substitution of the thiol group can be measured in accordance with ASTM-D817-96, one of the specifications specified/issued by ASTM (American Society for Testing and Materials).

If the number average molecular weight of the cellulose halide is in the range of 60,000 to 300,000, the mechanical strength of the resulting film is enhanced, so that it is preferable. More preferably, the fiber having a number average molecular weight of 70,000 to 200,000 is used. Sputum.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the cellulose halide are determined by gel permeation chromatography (GPC). The measurement conditions are as follows. Further, the measurement method can also be used as a method for measuring other polymers in the present embodiment.

Solvent: dichloromethane; column: Shodex K806, K805, K803G (manufactured by Showa Denko Co., Ltd.) was used as three connections; column temperature: 25 ° C; sample concentration: 0.1% by mass; detector: RI Model 504 (manufactured by GL SCIENCE); pump: L6000 (manufactured by Hitachi, Ltd.); flow rate: 1.0 ml/min

Calibration curve: A calibration curve obtained using 13 samples of standard polystyrene STK standard polystyrene (manufactured by TOSOH Co., Ltd.) Mw = 1000000 to 500. Thirteen samples were used at slightly equal intervals.

The residual sulfuric acid content in the cellulose halide is preferably in the range of 0.1 to 45 ppm by mass in terms of sulfur element. It is presumed that these are contained in the form of a salt. When the residual sulfuric acid content exceeds 45 ppm by mass, it tends to be easily broken during hot stretching or slapping after heat stretching. Further, the residual sulfuric acid content is more preferably in the range of 1 to 30 ppm by mass. The residual sulfuric acid content can be determined by the method specified in ASTM-D817-96.

Moreover, the free acid content in the cellulose halide is preferably 1~ 500 mass ppm. If it is the said range, since it is hard to break like the above, it is preferable. Further, the free acid content is preferably in the range of 1 to 100 ppm by mass, and becomes more difficult to break. In particular, it is preferably in the range of 1 to 70 ppm by mass. The free acid content can be determined by the method specified in ASTM-D817-96.

It is preferred that the residual sulfuric acid content and the free acid content are in the above range by sufficiently washing the cellulose halide after the synthesis.

The cellulose which is a raw material of the cellulose oxime is not particularly limited, and examples thereof include cotton linters, wood pulp, and kenaf. Further, the cellulose halide obtained by the above may be used in combination at any ratio.

Cellulose telluride can be produced by a known method. Specifically, for example, the synthesis can be carried out by referring to the method described in JP-A-10-45804.

Moreover, cellulose halides are also affected by trace amounts of metal components in the cellulose halide. Although such a trace amount of a metal component is presumably related to the water used in the manufacturing process, the component which may become an insoluble core is as small as possible. In particular, metal ions such as iron, calcium, magnesium, and the like may be formed by salt formation with a polymer decomposition product or the like having an organic acid group, and it is less preferable. Further, the calcium (Ca) component is an acidic component such as a carboxylic acid or a sulfonic acid, and a complex compound (i.e., a complex compound) is easily formed with most of the ligands, and a large amount of calcium derived from insoluble calcium is formed. Slag (insoluble precipitation, mixing Less turbid, so less is better.

Specifically, the content of the iron (Fe) component is preferably 1 ppm by mass or less in the cellulose halide. Further, the content of the calcium (Ca) component in the cellulose halide is preferably 60 ppm by mass or less, more preferably 0 to 30 ppm by mass. Further, as for the magnesium (Mg) component, if it is too large, an insoluble matter is generated. Therefore, the content of the cellulose halide is preferably from 0 to 70 ppm by mass, particularly preferably from 0 to 20 ppm by mass.

Further, the content of the metal component such as the content of the iron (Fe) component, the content of the calcium (Ca) component, and the content of the magnesium (Mg) component can be obtained by using a microwave digestion wet decomposition apparatus for the dried cellulose halide. Sulfuric acid was decomposed and pretreated by alkali fusion, and then analyzed by ICP-AES (inductively coupled plasma luminescence spectroscopic analyzer).

[Polycarbonate resin]

Various types of polycarbonate resin are used without particular limitation, and from the viewpoint of chemical properties and physical properties, an aromatic polycarbonate resin is preferable, and a bisphenol A-based polycarbonate resin is particularly preferable. Among them, those obtained by introducing a bisphenol A derivative such as a benzene ring, a cyclohexane ring, or an aliphatic hydrocarbon group into bisphenol A are more preferable. Further, a polycarbonate resin having a structure in which the anisotropy in a unit molecule is obtained by introducing a derivative of the above functional group asymmetrically into the carbon of the center of bisphenol A is particularly preferable. As such a polycarbonate resin, for example, two methyl groups of carbon in the center of bisphenol A are used as a substituent on the benzene ring, and one hydrogen of each benzene ring of bisphenol A is used as a A polycarbonate resin obtained by asymmetrically replacing a central carbon with a phenyl group or the like.

Specifically, those obtained by a phosgene method or a transesterification method from a 4,4'-dihydroxydiphenyl alkane or a halogen substituent thereof may, for example, be 4,4'-dihydroxydiphenylmethane. 4,4'-dihydroxydiphenylethane, 4,4'-dihydroxydiphenylbutane, and the like. In addition, Japanese Laid-Open Patent Publication No. 2006-215465, JP-A-2006-91836, JP-A-2005-121813, JP-A-2003-167121, and Japan A polycarbonate-based resin described in, for example, Japanese Laid-Open Patent Publication No. 2012-67300, No. 00-26705, and the like.

The polycarbonate resin can be used by mixing with a transparent resin such as a polystyrene resin, a methyl methacrylate resin, or a cellulose acetate resin. Further, a resin layer containing a polycarbonate resin may be laminated on at least one of the resin films formed of the cellulose acetate resin.

The polycarbonate resin preferably has a glass transition point (Tg) of 110 ° C or higher and a water absorption ratio (a value measured under conditions of 24 hours in 23 ° C water) of 0.3% or less. Further, it is more preferable that the Tg is 120 ° C or more and the water absorption rate is 0.2% or less.

The polycarbonate resin film which can be used in the present embodiment can be formed into a film by a known method. Among them, a solution casting method or a melt casting method is preferred.

<additive>

The long film of this embodiment may also contain an additive. As the additive, there are a plasticizer, an ultraviolet absorber, a hysteresis adjuster, an antioxidant, an anti-deterioration agent, a peeling aid, a surfactant, a dye, a fine particle, and the like. In the present embodiment, the additives other than the fine particles may be added during the preparation of the doping liquid, or may be added during the preparation of the fine particle dispersion.

(plasticizer)

Examples of the plasticizer to be added to the long film include a phthalate type, a fatty acid ester type, a trimellitate type, a phosphate type, a polyester type, a sugar ester type, and an acrylic polymer. Wait. Among them, from the viewpoint of moisture permeability, a plasticizer of a polyester-based or sugar-ester-based polymer can be preferably used.

The polyester-based plasticizer is superior in non-transferability or extraction resistance to a phthalate-based plasticizer such as dioctyl phthalate. It can be applied to a wide range of applications by selecting or using these plasticizers in accordance with the use. As the acrylic polymer, a homopolymer or a copolymer of acrylic acid or alkyl methacrylate is preferred. Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), and butyl acrylate. Ester (n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), decyl acrylate (n -, i-), tetradecyl acrylate (n-, i-), acrylic acid (2-ethylhexyl ester), acrylic acid (ε-caprolactone), acrylic acid (2-hydroxyethyl ester), propylene Acid (2-hydroxypropyl), acrylic acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), acrylic acid (2-methoxyethyl), acrylic acid (2- Ethyl ethoxylate or the like, or the above acrylate is changed to methacrylate. The acrylic polymer is a homopolymer or a copolymer of the above monomers, but preferably has a methyl acrylate monomer unit of 30% by mass or more, and more preferably has a methyl methacrylate monomer unit. 40% by mass or more. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.

The polyester-based plasticizer is a reactant of a monovalent to tetravalent carboxylic acid and a monovalent to hexavalent alcohol, but mainly obtained by reacting a divalent carboxylic acid with a diol. Typical examples of the divalent carboxylic acid include glutaric acid, itaconic acid, adipic acid, phthalic acid, sebacic acid, and sebacic acid. Further, the polyester-based plasticizer is preferably an aromatic terminal ester-based plasticizer. The aromatic terminal ester-based plasticizer preferably has an ester compound having a structure in which phthalic acid, adipic acid, at least one benzene monocarboxylic acid, and at least one carbon number 2 to 12 alkanediol are reacted. . As long as it has a structure in which an adipic acid residue and a phthalic acid residue are used as a final compound, when an ester compound is produced, it can be reacted as an acid anhydride or an esterified product of a dicarboxylic acid.

As the benzene monocarboxylic acid component, for example, benzoic acid, p-tert-butylbenzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, n-propylbenzoic acid are present. Aminobenzoic acid, ethoxylated benzoic acid, etc., preferably benzoic acid. Further, these may be used alone or as a mixture of two or more.

Examples of the alkanediol component having 2 to 12 carbon atoms include: Glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1, 4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentylene glycol), 2,2-diethyl-1,3-propanediol (3, 3-trimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-trimethylolpheptane), 3-methyl-1,5-pentyl Glycol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8 - octanediol, 1,9-nonanediol, 1,10-nonanediol, 1,12-octadecanediol, and the like. Among these, especially 1,2-propanediol is preferred. These diols may be used singly or as a mixture of two or more.

The aromatic terminal ester-based plasticizer may be in the form of an oligoester or a polyester, and the molecular weight is preferably in the range of 100 to 10,000, but preferably in the range of 350 to 3,000. Further, the acid value is 1.5 mgKOH/g or less, and the hydroxy (hydroxyl) value is 25 mgKOH/g or less, preferably the acid value is 0.5 mgKOH/g or less, and the hydroxy (hydroxyl) value is 15 mgKOH/g or less.

Specific examples thereof include the compounds shown below, but are not limited thereto.

As an ester other than the cellulose ester of the sugar ester-based compound, a compound obtained by esterifying all or a part of the OH group of a sugar such as a monosaccharide, a disaccharide, a trisaccharide or an oligosaccharide is more specifically exemplified. Can be enumerated A compound represented by the general formula (4) or the like.

In the formula, R ₁ to R ₈ represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted arylcarbonyl group having 2 to 22 carbon atoms. The R ₁ to R ₈ systems may be the same or different.

In the following, the compound represented by the general formula (4) is specifically shown (compound 1-1 to compound 1-23), but it is not limited thereto. Further, when the average degree of substitution in the following table is less than 8.0, one of R ₁ to R ₈ represents a hydrogen atom.

The plasticizer is preferably added in an amount of from 0.5 to 30 parts by mass based on 100 parts by mass of the cellulose ester film.

(hysteresis adjuster)

As the compound to be added to adjust the hysteresis, an aromatic compound having two or more aromatic rings as described in the specification of European Patent No. 911,656A2 can be used.

Further, two or more kinds of aromatic compounds may be used in combination. The aromatic ring of the aromatic compound preferably contains an aromatic hetero ring in addition to the aromatic hydrocarbon ring. The aromatic heterocyclic ring is generally an unsaturated heterocyclic ring. Among them, a 1,3,5-triazine ring is particularly preferred.

(polymer or oligomer)

The long film of the present embodiment preferably contains a cellulose ester, and has a substituent selected from a carboxyl group, a hydroxyl group, an amine group, a guanamine group, and a sulfonic acid group, and has a weight average molecular weight of 500 to 200,000. A polymer or oligomer of a vinyl compound within. Preferably, the mass ratio of the cellulose ester to the polymer or oligomer is in the range of 95:5 to 50:50.

(matting agent)

In the present embodiment, fine particles can be contained in the long film as a matting agent, whereby the transport and winding of the long film and the long oblique alignment film produced using the long film can be easily performed.

The particle size of the matting agent is preferably a primary particle or a secondary particle of 10 nm to 0.1 μm. A slightly spherical matting agent having a needle-like ratio of primary particles of 1.1 or less can be preferably used.

It is preferable that the fine particle system is contained, and it is preferably cerium oxide. Examples of the fine particles of ceria which are preferred in the present embodiment include AEROSIL R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, and TT600 manufactured by Japan AEROSIL Co., Ltd. (the above is The trade name of Japan AEROSIL Co., Ltd. is commercially available, and AEROSIL 200V, R972, R972V, R974, R202, and R812 can be preferably used. Examples of the fine particles of the polymer include an anthrone resin, a fluororesin, and an acrylic resin. More Preferably, the fluorenone resin is preferably a three-dimensional network structure. Examples of such a resin include TOSPEARL 103, 105, 108, 120, 145, 3120, and 240 (TOSHIBA SILICON).

The fine particles of cerium oxide are preferably those having a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g/L or more. More preferably, the average diameter of the primary particles is 5 to 16 nm, and more preferably 5 to 12 nm. If the average diameter of the primary particles is smaller, the haze is preferably lower. The apparent specific gravity is preferably 90 to 200 g/L or more, more preferably 100 to 200 g/L or more. When the apparent specific gravity is larger, it is preferable that a fine particle dispersion liquid having a high concentration can be produced without generating a mist or agglomerates.

The amount of the matting agent to be added in the present embodiment is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.3 g, and still more preferably 0.08 to 0.16 g per 1 m ² of the long film.

(other additives)

In addition to this, a thermal stabilizer such as inorganic fine particles such as kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, or aluminum oxide, or a salt of an alkaline earth metal such as calcium or magnesium may be added. Further, a surfactant, a peeling accelerator, an antistatic agent, a flame retardant, a lubricant, an oil agent, or the like may be added.

<Characteristics of long film> (tension softening point)

The long film of the present embodiment is required to be able to withstand use in a higher temperature environment. Therefore, the tensile softening point of the long film is preferably from 105 ° C to 145 ° C, and is preferably from 110 ° C to 130 ° C.

As a specific measurement method of the tension softening point, for example, a TENSILON tester (RTC-1225A, manufactured by ORIENTEC Co., Ltd.) can be used, and the sample film can be cut out to 120 mm (vertical) × 10 mm (wide), and one side can be 10 N. While the tension was stretched, the temperature was continuously raised at a temperature increase rate of 30 ° C/min, and the temperature at the time point of 9 N was measured three times, and the average value was obtained from the average value.

(dimension change rate)

In the case where the film in which the long film of the present embodiment is obliquely stretched is used in an organic EL image display device, changes in thickness or phase difference occur in order to avoid a change in size due to moisture absorption. And the problem of reduction in contrast or color unevenness, the dimensional change rate (%) of the obliquely stretched film is preferably less than 0.5%, and more preferably less than 0.3%.

(defect)

In the long film of the present embodiment, it is preferred that the film has few defects. Here, the defect refers to a void (foaming defect) in the film which occurs due to rapid evaporation of the solvent in the drying step of the solution film formation, or is caused by Foreign matter (foreign matter defect) in the film caused by foreign matter in the film forming solution or foreign matter mixed in the film forming.

Specifically, it is preferable that the defect having a diameter of 5 μm or more in the plane of the film is one/10 cm square or less. More preferably, it is 0.5 /10 cm square or less, and even more preferably 0.1 /10 cm square or less.

The diameter of the above defect, when the defect is circular, indicates the diameter thereof. When it is not circular, the range of the defect is determined by the microscope as follows, and the maximum diameter is set ( The diameter of the circumscribed circle).

The range of defects, when the defect is a bubble or foreign matter, is the size of the shadow when the defect is observed by the transmitted light of the differential interference microscope. In the case where the defect is a change in the surface shape such as transfer or scratch of the roller flaw, the defect is observed by the reflected light of the differential interference microscope and the size is confirmed.

Further, in the case of observation by reflected light, if the size of the defect is unknown, aluminum or platinum is vapor-deposited on the surface for observation. In order to obtain a film excellent in quality represented by the frequency of the defect, the polymer solution is subjected to high-precision filtration immediately before casting, or the degree of cleanness of the periphery of the casting machine is increased, or casting is performed. The subsequent drying conditions are preferably set in a stepwise manner, and it is effective to dry and suppress the foaming.

If the number of defects is more than one/10 cm square or less, if the tension is applied to the film, for example, during processing in a subsequent step, the film may be broken due to the defect, and the productivity may be lowered. condition. In addition, when the diameter of the defect is 5 μm or more, it can be visually confirmed by observation of a polarizing plate or the like, and when it is used as an optical member, a bright spot may be generated.

(total light transmittance)

The long film of the present embodiment preferably has a total light transmittance of 90% or more, more preferably 93% or more. Moreover, the upper limit of the practicality of the total light transmittance is about 99%. In order to achieve excellent transparency represented by the total light transmittance, it is configured not to introduce an additive or a copolymerization component that absorbs visible light, or to remove foreign matter in the polymer by high-precision filtration to cause light inside the film. The means of diffusion or absorption reduction is effective. Further, the surface of the film surface is reduced by reducing the surface roughness of the film contact portion (the cooling roll, the calender roll, the roll, the belt, the coated substrate in the solution film formation, the transfer roll, etc.) at the time of film formation. A means for reducing the thickness to reduce the diffusion or reflection of light on the surface of the film is also effective.

<Formation method of long film>

The long film of the present embodiment containing the above resin can be formed by one of the solution casting film forming method or the melt casting film forming method described below. In addition, although the case where the long film is a cellulose ester type resin is demonstrated here, it is the same also in the case of containing other resin.

In the case of producing a long film by a solution casting film forming method, it is a blending of a raw material solution of a long film as a cellulose ester resin. The dopant is cast by a casting die on a support made of a rotating metal endless belt. The dopant film formed on the support by casting is a web which is peeled off by a peeling roll when it is cycled on the support for about one week. The strip (film) to be peeled off is introduced into an extension device formed by a tenter.

In the case of producing a long film by a melt casting film forming method, in the method of extruding a T-die, it is melted at a temperature at which the polymer can be melted, and is formed into a film shape from the T-die. The film is extruded onto a cooling cylinder and allowed to cool and solidify, and the film is peeled off from the cooling cylinder. The peeled film is introduced into an extension device formed by a tenter.

Hereinafter, the details of each film forming method will be described.

[solution casting film forming method]

In the method for producing a long film by a solution casting film forming method, the solid content concentration of the dopant as the cellulose ester solution is usually about 10 to 40% by mass, and the flow delay in the casting step The dopant viscosity is modulated to a range of 1 to 200 poise.

Here, first, the dissolution of the cellulose ester is usually carried out by means of a stirring and dissolving method in a dissolution vessel, a heating and dissolving method, an ultrasonic dissolving method, and the like, and further, in order to prevent being called a gel or a lump. The production of the bulk undissolved material is more preferably a method in which the temperature is increased to a temperature within a range of a normal pressure of the solvent at a pressure lower than the boiling point of the solvent, and the mixture is stirred while being stirred. Further, it is also possible to use the cooling and dissolving method described in Japanese Laid-Open Patent Publication No. Hei 9-95538, or A method of dissolving at a high pressure as described in Japanese Laid-Open Patent Publication No. Hei 11-21379.

After the cellulose ester is mixed with a poor solvent to wet or swell, a method of further mixing with a good solvent and dissolving it is also preferably used. In this case, a device for mixing and wetting or swelling the cellulose ester with a poor solvent may be used independently of the device which is mixed with the good solvent and dissolved.

The type of the pressurized container to be used for the dissolution of the cellulose ester is not particularly limited as long as it can withstand a predetermined pressure and can be heated and stirred under pressure. In addition, in the pressurized container, a gauge such as a pressure gauge or a thermometer is appropriately disposed. The pressurization may be carried out by a method of pressurizing an inert gas such as nitrogen or by raising the vapor pressure of the solvent by heating. The heating is preferably performed from the outside, and for example, a jacket type is preferable because temperature control is easy.

The heating temperature of the solvent to be added is not less than the boiling point of the solvent to be used. In the case of two or more kinds of mixed solvents, it is preferred to heat the temperature to a temperature higher than the boiling point of the solvent having a lower boiling point and not to boil the solvent. The temperature of the range. If the heating temperature is too high, the required pressure will become large, and the productivity will be deteriorated. The preferred heating temperature ranges from 20 to 120 ° C, more preferably from 30 to 100 ° C, and even more preferably from 40 to 80 ° C. Further, the pressure is adjusted so as not to boil the solvent at a set temperature.

In addition to cellulose esters and solvents, it is also necessary The additive such as a plasticizer or an ultraviolet absorber is previously mixed with a solvent to be dissolved or dispersed, and then introduced into a solvent before dissolution of the cellulose ester, or may be added to a dopant after dissolution of the cellulose ester.

After the cellulose ester is dissolved, it is taken out from the container while being cooled, or is taken out from the container by a pump or the like and cooled by a heat exchanger or the like to supply the obtained cellulose ester. The film is formed by a dopant, but cooling at this time can also be carried out until normal temperature.

When the mixture of the cellulose ester raw material and the solvent is dissolved by a dissolving device having a stirrer, it is preferred to set the peripheral speed of the stirring blade to at least 0.5 m/sec or more, and to dissolve by stirring for 30 minutes or longer.

The foreign matter contained in the cellulose ester dopant (especially a foreign matter which is mistaken for an image in a liquid crystal display device) must be removed by filtering the dopant. It can be said that the quality as an optical film depends on this filtration.

The filter medium used for the filtration is preferably one having a small absolute filtration accuracy. However, if the absolute filtration accuracy is too small, the filter material is likely to be clogged, and the filter material must be exchanged frequently, so that the productivity is lowered. The problem. Therefore, the filter medium used for the cellulose ester dopant is preferably a filter having an absolute filtration accuracy of 0.008 mm or less, more preferably 0.001 to 0.008 mm, and more preferably a range of 0.003 to 0.006 mm.

The material of the filter material is not particularly limited, and a normal filter medium can be used. However, a filter material made of a plastic fiber such as polypropylene or TEFLON (registered trademark) or a metal filter material such as stainless steel fiber is free from fibers. Wait, and it is better.

The filtration method of the cellulose ester dopant can be carried out by a usual method, but the method of filtering while heating under pressure at a temperature equal to or higher than the boiling point of the solvent at normal pressure and not boiling the solvent is a filter medium. The increase in the differential pressure (hereinafter, referred to as the filtration pressure) before and after is small, and is preferable.

The preferred filtration temperature ranges from 45 to 120 ° C, more preferably from 45 to 70 ° C, and even more preferably from 45 to 55 ° C.

The filtration pressure is preferably 3,500 kPa or less, more preferably 3,000 kPa or less, and still more preferably 2,500 kPa or less. In addition, the filtration system can be controlled by appropriately selecting the filtration flow rate and the filtration area.

In order to produce a long film of a cellulose ester resin, first, a cellulose ester solution is prepared by dissolving a cellulose ester in a mixed solvent of a good solvent and a poor solvent, and adding the above-mentioned plasticizer or ultraviolet absorber thereto. Doping).

The dopant can be cast on the support in a range of from 0 ° C to the boiling point of the solvent, and can also be cast in a temperature range of from 5 ° C to the boiling point of the solvent of -5 ° C. On the support, it is better to cast on the support at a temperature range of 5 to 30 °C. At this time, it is necessary to control the ambient temperature above the dew point.

Further, the dopant adjusted so that the dopant viscosity is 1 to 200 poise is cast from the casting die so as to have a substantially uniform film thickness on the support, so that the casting is performed. When the amount of residual solvent in the film is 200% or more based on the weight of the solid component, the cast film temperature becomes a solvent. The cast film (belt) is dried by a dry air when the amount of the residual solvent is 200% or less and the cast film temperature is in the range of the boiling point of the solvent + 20 ° C or less.

Here, the amount of residual solvent is expressed by the following formula.

Residual solvent amount (% by mass) = {(M - N) / N} × 100

However, in the formula, the weight of the M-belt at any time point, N is the weight of the weight M after drying at 110 ° C for 3 hours.

In the support, in order to allow the tape to be dried and solidified until it is capable of being peeled off from the support, it is preferred to dry until the amount of residual solvent in the tape is 150% by mass or less, more preferably 50 to 120%. .

The tape temperature at which the tape is peeled off from the support is preferably 0 to 30 °C. Further, since the tape is immediately peeled off from the support, the temperature is temporarily lowered rapidly due to evaporation of the solvent generated from the side of the support surface, and the volatile components such as water vapor or solvent vapor in the environment are It is easy to coagulate, so the strip temperature at the time of peeling is preferably 5 to 30 ° C.

In the drying step of the belt (or film), the belt is usually suspended by a roll suspension method or by a needle comb drawing method or a belt tenter method.

The strip after peeling is, for example, introduced into a primary drying device. In a primary drying apparatus, the belt is serpentinely conveyed by a plurality of conveying rollers arranged in a staggered manner when viewed from the side, during which the belt is blown from the top plate of the drying device. The air is dried by the warm air discharged from the bottom of the drying device.

Next, the obtained film (sheet) is extended in a uniaxial direction. By extension, the molecular system is aligned. The method of performing the stretching is not particularly limited, but a well-known needle comber or a tenter type tenter or the like can be preferably used. The extending direction may be the length direction, the width direction, or any direction (inclination direction), but it is easy to adjust the breaking elongation of the long film by setting the extending direction to the width direction (Breaking) Elongation), and better.

In particular, in the drying step after being peeled off from the support, the belt tends to shrink in the width direction due to evaporation of the solvent. If the drying is performed at a higher temperature, the shrinkage becomes larger. From the viewpoint of improving the planarity of the completed film, it is preferred to perform drying while suppressing the shrinkage as much as possible. Based on this point of view, for example, it is preferable to use a clamp to widen the width in the width direction of all the drying steps or a part of the drying step as disclosed in Japanese Laid-Open Patent Publication No. 62-46625 A method of maintaining the width at both ends of the web to make it dry (triangular manner).

As a condition for extending the long film, the temperature and the magnification can be selected in such a manner that the desired breaking elongation characteristics can be obtained. Usually, the stretching ratio is 1.1 to 2.0 times, preferably 1.2 to 1.5 times, and the stretching temperature is usually set at a glass transition temperature (Tg) of -40 ° C to Tg + 50 ° C of the resin constituting the sheet, preferably set. In the temperature range of Tg-40 ° C ~ Tg + 40 ° C. If the stretching ratio is too small, the desired breaking elongation characteristics may not be obtained. Conversely, if the stretching ratio is too large, the breaking may occur. If the extension temperature is too low, there will be a breakage. Moreover, if it is too high, the desired breaking elongation characteristic may not be obtained.

When the breaking elongation characteristic of the thermoplastic resin film produced by the above method is corrected to a desired property for the purpose of blending, the film may be stretched or shrunk in the longitudinal direction or the width direction. In order to shrink it in the longitudinal direction, for example, there is a method of relaxing the lengthwise direction by extending the wide width as a temporary looseness, or gradually spacing the adjacent turns of the lateral stretching device. A method of narrowing to shrink the film. In the latter method, the 铗 portion can be driven and gradually smoothed, for example, by a pantograph method or a linear driving method by using a general simultaneous biaxial stretching device. The method of narrowing is carried out.

The holding and stretching of the tenter can be carried out at any position within a range of 50 to 150% by mass of the film immediately after being peeled off, and the amount of residual solvent before being wound up is 0% by mass. However, it is preferably carried out in the range of 5 to 10% of the residual solvent.

The tenter is also generally divided into a plurality of temperature zones in the advancing direction of the substrate. The temperature at the time of stretching is selected to obtain a desired physical property or planarity. However, the temperature of the drying zone before and after the tenter is selected to have a temperature different from the temperature at which the stretching is performed for various reasons. For example, when the ambient temperature in the drying zone before the tenter is different from the temperature in the tenter, the temperature of the region near the entrance of the tenter is generally set to the temperature and the temperature of the drying zone before the tenter. The temperature of the intermediate temperature of the central part of the web. For the tenter and the inside of the tenter The temperature is different, and the temperature in the region near the exit of the tenter is similarly set to the temperature between the tenter and the temperature in the tenter. The temperature of the drying zone before and after the tenter is generally 30~120 °C, preferably 50~100 °C, and the temperature of the extension part of the tenter is 50~180 °C, preferably 80~170 °C, tenter The temperature at the inlet or outlet is suitably selected by the intermediate temperature of the temperatures.

The form of extension, that is, the trajectory of holding the cymbal, is selected based on the optical properties or planarity of the film, and has various forms, but the multi-use is temporarily maintained at a certain width after the start of the control. It is then stretched and held in a certain width after the end of the extension. In the vicinity of the end of the gripper exit near the exit of the tenter, in order to suppress the vibration of the substrate caused by the opening of the gripper, the width is generally relieved.

Although the extended form is related to the extension speed, the extension speed is generally 10 to 1000 (%/min), preferably 100 to 500 (%/min). This extension speed is not constant when the trajectory of the ridge is a curve, but gradually changes in the direction before the substrate.

Further, the dried belt (film) obtained by the tenter method described above is then introduced into a secondary drying apparatus. In the secondary drying apparatus, the belt is serpentine conveyed by a plurality of conveying rollers arranged in a staggered shape when viewed from the side, and during this period, the belt is blown from the top plate of the secondary drying device. The mixture was dried by a warm air discharged from the bottom of the secondary drying device, and taken up by a coiler as a long film of a cellulose ester resin.

The means for drying the belt is not particularly limited, and general hot air, infrared rays, heating rolls, microwaves, and the like are used. The viewpoint of simplicity is preferably drying by hot air. The drying temperature is preferably from 40 to 150 ° C, and the viewpoint of improving planarity and dimensional stability is more preferably 80 to 130 ° C.

In the drying step of the belt, the belt which is peeled off from the support is further dried, and finally, the amount of the residual solvent is 3% by mass or less, preferably 1% by mass or less, more preferably 0.5% by mass or less. It is preferable from the viewpoint of obtaining a film having a good dimensional stability.

The steps from the casting to the subsequent drying may be carried out in an air atmosphere or in an inert gas atmosphere such as nitrogen. In this case, of course, the critical concentration of the outbreak of the solvent is considered to carry out the drying environment.

Further, it is preferable that the long film of the cellulose ester-based resin which has been subjected to the transport drying step is subjected to a strip of the cellulose ester resin by the embossing apparatus at the front stage of the introduction to the winding step. The embossing is formed on both side edges of the film. The embossing processing apparatus can be used, for example, in the apparatus described in Japanese Laid-Open Patent Publication No. S63-74850.

The coiler in the manufacture of the long film of the cellulose ester resin can be used by a general user, and can be fixed by a constant tension method, a constant torque method, a taper tension method, and an internal stress. The winding method such as the program tension control method performs the winding.

The film thickness of the long film after winding is different depending on the purpose of use, but the film thickness ranges from 20 to 200 μm, and the recent thinning tendency In particular, it is preferably in the range of 30 to 120 μm, particularly preferably in the range of 40 to 100 μm.

[Melt casting film forming method]

As the melt casting film forming method, there are a melt extrusion method, a calendaring method, a hot stamping method, an injection molding method, and the like using a method using a T-die or an expansion method. Among them, a method in which the thickness variation is reduced, the thickness is easily processed to a thickness of about 50 to 500 μm, and the T-die can be reduced in which the thickness difference or the hysteresis is reduced. The T-die extrusion method is a method in which a polymer can be melted at a temperature at which the polymer is melted, and is extruded from a T-die into a cooling cylinder in a film form (sheet shape), cooled and solidified, and then peeled off from the cooling cylinder. The obtained film is excellent in thickness precision and can be preferably used.

The melt extrusion can be carried out under the same conditions as those used in thermoplastic resins such as other polyesters. For example, the cellulose ester which has been dried under hot air or under vacuum or under reduced pressure can be melted by using a uniaxial or 2-axis type extruder at a temperature of about 200 to 300 ° C, and is formed by a blade disc type. The filter or the like is filtered to remove the foreign matter, and then cast from a T-die into a film shape (flaky shape) and solidified on a cooling cylinder. When it is introduced from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition or the like under a reduced pressure or an inert gas atmosphere.

The discharge flow rate is preferably configured to be carried out stably by introducing a gear pump or the like. Further, as the screen used for the removal of the foreign matter, a stainless steel fiber sintered sieve can be preferably used. Stainless steel fiber sintered filter After the stainless steel fiber body is in a state of being complicatedly entangled, and compression is performed and the contact portion is sintered and integrated, the density can be changed by the thickness and compression amount of the fiber, and the filtration precision can be adjusted. It is preferable to use a multilayer body in which filtration precision is repeated and densely repeated plural times. In addition, by adopting a configuration in which the filtration accuracy is gradually increased, or a method in which the filtration accuracy is repeated and densely repeated, the filtration life of the filter can be extended, and the capturing accuracy of foreign matter, gel, or the like can be improved. Therefore it is better.

If there is a flaw or a foreign matter adhering to the mold, there is a case where a rib-like defect occurs. Such a defect is called a mold line, and in order to reduce the defects on the surface of the mold line or the like, it is preferable that the piping from the extruder to the mold is configured to reduce the retention portion of the resin as much as possible. Further, it is preferred to use as much as possible that there is no scratch in the interior of the mold or in the lip. Since a volatile component is precipitated from the resin and formed as a mold line in the periphery of the mold, it is preferable to attract the environment containing the volatile component. Further, since precipitation occurs in a device that applies static electricity or the like, it is preferable to apply an alternating current or to prevent precipitation by another heating means.

The additive such as a plasticizer may be mixed with the resin in advance or may be mixed in the middle of the extruder. In order to carry out the addition uniformly, it is preferred to use a mixing device such as a static mixer.

The temperature of the cooling cylinder is preferably below the glass transition temperature of the thermoplastic resin. In order to adhere the resin to the cooling cylinder, it is preferable to use a method in which it is adhered by applying static electricity, and it is adhered by wind pressure. A method of squeezing a full width or an end portion to make it dense, a method of adhering it by decompression, and the like.

The long film of the thermoplastic resin formed by the melt casting film forming method is different from the long film formed by the solution casting film forming method, and has a characteristic that the thickness direction retardation (Rt) is small. There is also a case where it is necessary to adopt an extension condition different from the solution casting film forming method. In order to obtain desired optical properties, depending on the case, both the extension of the film in the forward direction and the extension in the film width direction may be performed simultaneously or sequentially. Further, depending on the case, there may be cases where only the width direction of the film is extended. By this extension operation, the molecular system is aligned and the film is adjusted to the desired hysteresis value.

In the case where the long film of the present embodiment is produced by a melt casting film forming method, as the usable ultraviolet absorber, a long film which is formed by the above-described solution casting film forming method can be used. The user of the manufacturing method is substantially the same.

The blending amount of the ultraviolet absorber is preferably in the range of 0.01 to 10% by mass based on the thermoplastic resin, and more preferably 0.1 to 5% by mass. If the amount used is too small, the ultraviolet absorbing effect may be insufficient. On the other hand, if the amount is too large, the transparency of the film may be deteriorated. The ultraviolet absorber is preferably one having a high thermal stability.

In the long film, fine particles for imparting lubricity to the film are preferably added. The fine particles to be used may be any of an inorganic compound or an organic compound as long as it has heat resistance at the time of melting. For example, as the inorganic compound, a compound containing ruthenium is preferable. Ceria, alumina, zirconia, calcium carbonate, talc, clay, calcined kaolin, calcined calcium citrate, hydrated calcium citrate, aluminum citrate, magnesium citrate and calcium phosphate, etc. Inorganic compound or zirconia. Among them, it is particularly preferable to use cerium oxide from the viewpoint of suppressing the haze to be small. In the case where the long film is produced by a melt casting film forming method, the matting agent to be used may be used in a method for producing a long film obtained by the above-described solution casting film forming method. The users are roughly the same.

<Specifications of long film>

The thickness of the long film in the present embodiment is 1 to 400 μm, preferably 20 to 200 μm, more preferably 30 to 120 μm, and particularly preferably 40 to 100 μm.

The width of the long film is not particularly limited, but may be 500 to 4000 mm, preferably 1000 to 2000 mm.

The preferred elastic modulus at the elongation temperature at the time of oblique stretching of the long film is 0.01 MPa to 5000 MPa, more preferably 0.1 MPa to 500 MPa, as expressed by Young's modulus. When the modulus of elasticity is too low, the shrinkage ratio at the time of stretching and stretching is low, and the wrinkle system is difficult to eliminate. Further, when the modulus of elasticity is too high, the tension applied during stretching becomes large, and it is necessary to increase the strength of the portion holding the both side edges of the film, and the load for the tenter in the subsequent step becomes large.

As the long film system, a non-aligned person can be used, and a film having an alignment in advance can be supplied. Also, if necessary, the strip film The distribution in the width direction of the direction may also be arcuate, that is, a so-called bowing shape. The key point is that the alignment state of the long film can be adjusted so that the alignment of the film at the position where the subsequent step is extended can be in a desired alignment state.

<Manufacturing method and manufacturing apparatus of inclined alignment film>

Next, a method and a manufacturing apparatus for producing an inclined alignment film which is an elongated oblique alignment film (inclined stretch film) which extends the above-mentioned elongated film in the oblique direction with respect to the width direction will be described.

<Method and Apparatus for Manufacturing Optical Film>

Then, the elongated film is stretched in the oblique direction with respect to the width direction to form an elongated oblique alignment film, and both ends of the oblique alignment film in the width direction are cut and removed, and the remaining portion is removed. The product part will be described as a method of manufacturing an optical film of an optical film and a manufacturing apparatus.

(summary of the device)

Fig. 1 is a plan view schematically showing a schematic configuration of an optical film manufacturing apparatus 1. In the manufacturing apparatus 1, the film feeding portion 2, the conveying direction changing portion 3, the guide roller 4, the extending portion 5, the guide roller 6, and the conveying direction changing portion 7 are sequentially provided from the upstream side in the conveying direction of the long film. The film cutting device 8 and the film winding unit 9. The details of the extension portion 5 and the film cutting device 8 will be described later.

The film feeding portion 2 feeds the above-described long film and supplies it to the extending portion 5. The film feeding portion 2 can be configured independently of the film forming device of the long film, or can be integrally formed. In the case of the former, after the film formation of the long film, the film is once wound up on the winding core, and the wound body is loaded into the film feeding portion 2, whereby the long film is sent out from the film feeding portion 2. . On the other hand, in the latter case, the film feeding portion 2 does not take up the long film after the film is formed, but feeds the extending portion 5.

The conveyance direction changing unit 3 changes the conveyance direction of the long film fed from the film feed unit 2 to the direction of the entrance of the extension portion 5 which is an obliquely extending tenter. The conveyance direction changing unit 3 includes, for example, a turn bar that changes the conveyance direction while being conveyed by the conveyance film, or a rotary table that rotates the rotary bar in a plane parallel to the film. .

In the conveyance direction changing unit 3, the conveyance direction of the long film is changed as described above, and the width of the entire manufacturing apparatus 1 can be further narrowed, and the position and angle of the film can be finely controlled. In addition, a long oblique alignment film having a small film thickness and a small difference in optical value can be obtained. In addition, when the film feeding portion 2 and the conveying direction changing portion 3 are movable (slidable and rotatable), it is possible to effectively prevent the left and right ends of the long film from being stretched at the extending portion 5 in the width direction.铗 (handle) is poorly bitten into the film.

Further, the film delivery unit 2 described above may be configured to be capable of ejecting a long film at a predetermined angle with respect to the entrance of the extending portion 5. Slide and rotate. In this case, the configuration in which the transport direction changing unit 3 is omitted may be omitted.

The guide roller 4 is provided at least one upstream side of the extending portion 5 in order to stabilize the track when the long film is traveling. Further, the guide roller 4 may be constituted by holding a pair of roller pairs on the upper and lower sides of the film, or may be constituted by a plurality of roller pairs. The guide roller 4 closest to the entrance of the extending portion 5 is a passive roller that guides the traveling of the film, and is rotatably supported by a shaft portion (not shown). As the material of the guide roller 4, a well-known material can be used. Further, in order to prevent scratches on the film, it is preferable to apply a ceramic coating on the surface of the guide roller 4, or to apply weight chrome plating or the like to a light metal such as aluminum to lighten the guide roller 4.

Further, it is preferable that one of the rollers on the upstream side of the guide roller 4 closest to the inlet of the extending portion 5 is pressed against the rubber roller and pinched. By setting such a nip roller, it is possible to suppress the change in the tension in the flow direction of the film.

A bearing portion of one of the opposite ends (left and right) of the guide roller 4 closest to the entrance of the extending portion 5 is provided with a first tension detecting device and a second tension detecting device for detecting the roller. A film tension detecting device for tension generated by a film. As the film tension detecting device, for example, a load cell can be used. As the load cell, a known type of stretched or compressed type can be used. The load cell is a device that converts the load acting at the force point into an electrical signal and detects it by a deflection meter installed on the deflection source.

The load cell is placed on the left and right bearing portions of the guide roller 4 disposed closest to the entrance of the extension portion 5, and the force of the film under walking acting on the roller is also near the sides of the film. The tension generated in the advancing direction of the film is detected independently of each other. Further, a deflection gauge may be directly attached to the support body constituting the bearing portion of the roller, and the load may be detected based on the deflection generated by the support, that is, the film tension may be detected. The relationship between the resulting deflection and the film tension is known in advance and is known.

The position of the film supplied from the film feeding portion 2 or the conveying direction changing portion 3 to the extending portion 5 and the direction in which the conveying direction deviates from the position toward the inlet of the extending portion 5 and the conveying direction are caused by the amount of deviation. On the other hand, the tension near the side edges of the film of the guide roller 4 closest to the entrance of the extending portion 5 is different. Therefore, the above-described tension difference can be detected by providing the film tension detecting device as described above, and the degree of the deviation can be determined. In other words, if the transport position and the transport direction of the film are appropriate (in the position and direction toward the entrance of the extension portion 5), the load acting on the guide roller 4 is substantially equal at both ends in the axial direction. However, if it is not appropriate, there will be a difference in film tension between the left and right.

Therefore, the film position and the conveyance direction of the film are appropriately adjusted by, for example, the above-described conveyance direction changing unit 3 so that the film tension difference between the right and left sides of the guide roller 4 closest to the entrance of the extension portion 5 is equal. With respect to the angle of the entrance of the extension portion 5, the holding of the film by the grip of the entrance portion of the extension portion 5 is stabilized, and the occurrence of an obstacle such as loosening of the gripper can be reduced. Further, the tilt caused by the extension portion 5 can be made The physical properties of the stretched film in the width direction are stable.

The guide roller 6 is provided with at least one downstream side of the extending portion 5 in order to stabilize the track during traveling of the film which is obliquely extended by the extending portion 5.

The conveyance direction changing unit 7 changes the conveyance direction of the film which has been extended from the extension unit 5 to the direction toward the film winding unit 9.

Here, in order to slightly adjust the alignment angle (the direction of the retardation axis in the in-plane of the film) or the type of the product, it is necessary to perform the film advancing direction at the entrance of the extending portion 5 and the exit of the extending portion 5. The adjustment of the angle between the advancing directions of the film. In order to adjust the angle, it is necessary to change the film advance direction of the film formed by the conveyance direction changing unit 3 to guide the film to the entrance of the extension portion 5, and/or to change by the conveyance direction changing unit 7. The film leading from the outlet of the extension 5 advances in the direction and returns the film to the direction of the film take-up portion 9.

Further, from the viewpoint of productivity or productivity, it is preferred to carry out the film formation and the oblique stretching continuously. When the film forming step, the tilting step, and the winding step are continuously performed, the film direction advancement direction is changed by the conveyance direction changing unit 3 and/or the conveyance direction changing unit 7, and is made in the film forming step and the winding step. The film advances in the same direction, that is, the film is fed from the film feeding portion 2 in the forward direction (feeding direction) and is about to be taken up by the film winding portion 9 as shown in Fig. 1. The previous film advance direction (winding direction) is uniform, and the width of the entire device relative to the film advancement direction can be reduced.

Further, although it is not always necessary to make the film advance direction in the film forming step and the winding step, it is preferable to adopt a configuration in which the film feeding portion 2 and the film winding portion 9 do not interfere with each other. The film direction advancement direction is changed by the conveyance direction changing unit 3 and/or the conveyance direction changing unit 7.

The conveyance direction changing sections 3 and 7 as described above can be realized by a well-known technique such as an air flow roll or an air trunbar.

The film winding unit 9 winds up the film (optical film) conveyed from the extending portion 5 via the conveying direction changing unit 7 and the film cutting device 8, and is, for example, a hoisting device, an accumulating device, a driving device, or the like. And constitute. The film take-up portion 9 is preferably configured to be slidable in the lateral direction in order to adjust the winding position of the film.

The film take-up portion 9 is capable of finely controlling the drawing position and angle of the film so that the film can be pulled at a predetermined angle with respect to the exit of the extending portion 5. As a result, a long oblique alignment film having a small film thickness and a small difference in optical value can be obtained. Moreover, it is possible to effectively prevent the occurrence of wrinkles of the film, and since the take-up property of the film is improved, the film can be wound up in a long state.

The film take-up portion 9 constitutes a drawing portion for pulling a film which is extended by the extending portion 5 and conveyed by a certain tension. Further, between the extending portion 5 and the film winding portion 9, a pulling roller for pulling the film at a certain tension may be provided. Further, the above-described guide roller 6 may have a function as the above-described pull roller.

In the present embodiment, the drawing tension T (N/m) of the stretched film is adjusted between 100 N/m < T < 300 N/m, preferably 150 N/m < T < 250 N/m. . When the above-mentioned tensile tension is 100 N/m or less, the film is liable to be loosened or wrinkled, and the distribution in the width direction of the film having hysteresis and alignment angle is also deteriorated. On the other hand, when the pulling tension is 300 N/m or more, the unevenness in the width direction of the film of the alignment angle is deteriorated, and the wide-yield (efficiency in the width direction) is deteriorated.

Further, in the present embodiment, it is preferable that the fluctuation of the pulling tension T is controlled with an accuracy of less than ± 5%, and more preferably with an accuracy of less than ± 3%. When the variation of the pulling tension T is ±5% or more, the difference in optical characteristics in the wide direction and the flow direction (transport direction) becomes large. As a method of controlling the fluctuation of the pulling tension T within the above range, a method of measuring the load applied to the first roller (guide roller 6) on the outlet side of the extending portion 5, that is, a film, is exemplified. The tension is controlled so that the value of the winding roller of the take-up roll or film take-up portion 9 is controlled by a general PID control method. As a method of measuring the load, a method of attaching a load cell to the bearing portion of the guide roller 6 and measuring the load applied to the guide roller 6, that is, the tension of the film, is exemplified. A known type of stretch type or compression type can be used as the load cell system.

In addition, before the strip-shaped optical film is taken up, the mask film may be superposed on the optical film and simultaneously wound up, or may be wound up by the purpose of preventing the film from agglomerating with each other. Overlapping At least one of the optical films (preferably both) is attached to the end of the tape or the like. The mask film is not particularly limited as long as it can protect the optical film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.

Further, before the optical film is wound up, a phase called a knurling portion or an embossing portion may be formed by both end portions in the width direction of at least one side (preferably two surfaces) of the film. A portion (protrusion) that is higher than the film surface to prevent agglomeration of the films when the film is taken up. Further, the height and shape of the knurled portion may be different (may be asymmetrical) at both ends in the width direction.

(Details of the extension)

Next, the details of the above-described extension portion 5 will be described. Fig. 2 is a plan view schematically showing an example of the rail form of the extending portion 5. However, this is an example, and the configuration of the extension portion 5 is not limited thereto.

In the present embodiment, the extension portion 5 is formed by a tenter (inclined stretcher) that can be tilted and extended. This tenter is a device that heats a long strip of film to any temperature at which it can be extended and obliquely extends. The tenter includes a heating zone Z, a pair of left and right rails Ri, Ro, and a plurality of grippers Ci and Co that transport the film traveling along the rails Ri and Ro (in the second figure, Only one set of grippers is shown). In addition, the details of the heating zone Z will be described later. The rails Ri and Ro respectively form a plurality of rail portions connected by a connecting portion. (An example of the white ring system connecting portion in Fig. 2). The grippers Ci and Co are configured by holding both ends of the film in the width direction.

In Fig. 2, the feeding direction D1 of the long film is different from the winding direction D2 of the stretched optical film, and is at an angle of the angle θ i between the winding direction D2 and the winding direction D2. The delivery angle θ i can be arbitrarily set to a desired angle within a range of more than 0° and less than 90°.

In this manner, since the feeding direction D1 is different from the winding direction D2, the rail shape of the tenter is asymmetrical to the left and right, and the film transport path is curved on the way. Further, the rail shape can be manually or automatically adjusted in accordance with the alignment angle θ, the stretch ratio, and the like which are applied to the long oblique alignment film to be manufactured. In the tilting stretcher used in the manufacturing method of the present embodiment, it is preferable to be able to freely set the positions of the rail portions and the rail connecting portions constituting the rails Ri and Ro and to arbitrarily change the rail shape.

In the present embodiment, the plurality of grippers Ci and Co of the tenter are kept at a constant speed while maintaining a constant interval between the grippers Ci and Co. The walking speed of the holding device Ci and Co can be appropriately selected, but it is usually 1 to 150 m/min. In the present embodiment, in consideration of the productivity of the film, it is preferably 20 to 100 m/min. The difference between the traveling speeds of the pair of left and right grippers Ci and Co is usually 1% or less, and preferably 0.5% or less, more preferably 0.1% or less. This is because if there is a difference in the advance speed between the left and right sides of the film at the exit of the stretching step, wrinkles and deflections occur at the exit of the stretching step. Therefore, the difference in speed between the left and right grippers Ci and Co is required to be substantially the same speed. In general In the tenter device or the like, depending on the period of the teeth of the sprocket for driving the chain, the frequency of the drive motor, etc., there is a speed unevenness which is generated on a scale of seconds or less, and unevenness may be generated by several %. However, these do not conform to the speed difference described in this embodiment.

In the stretching machine used in the manufacturing method of the present embodiment, in particular, in a portion where the conveyance of the film is inclined, a large bending rate may be required at a rail that restricts the trajectory of the gripper. For the purpose of avoiding interference between the grippers or local stress caused by the sharp bending, it is preferable that the trajectory of the gripper is drawn as a curve in the curved portion.

In this way, in order to impart an obliquely extending tenter for the alignment of the long film in the oblique direction, it is preferable to freely set the alignment angle of the film by changing the shape of the rail, thereby further aligning the film. The shaft (slow phase axis) covers the width direction of the film to be equally aligned to the right and left, and the tenter can also control the film thickness or hysteresis with high precision.

Next, the extension operation of the extension portion 5 will be described. The long film is held at both ends by the left and right grippers Ci and Co, and is transported in the heating zone Z along with the walking of the grippers Ci and Co. The left and right grippers Ci and Co are in the entrance portion of the extension portion 5 (the position in the figure A), and are opposed to each other in a direction slightly perpendicular to the advance direction (feeding direction D1) of the film, and are not in the right direction. The symmetrical rails Ri and Ro respectively travel, and the exiting portion (the position of B in the figure) releases the held film at the end of the extension. It is released from the holding device Ci, Co The discharged film is taken up on the winding core by the film winding portion 9 described above. The pair of rails Ri and Ro each have a continuous track with no end, and the grippers Ci and Co which are released after the holding of the film at the exit portion of the tenter are walked on the outer rail and are sequentially returned. Entrance department.

At this time, since the rails Ri and Ro are asymmetrical to the left and right, in the example of Fig. 2, the grips Ci and Co which are opposite to each other in the position of A in the figure follow the rails Ri and Ro. On the other hand, the gripper Ci that is traveling on the rail Ri side (inner rail side) advances in a positional relationship with respect to the gripper Co that travels on the rail Ro side (outer rail side).

That is, when the position of A in the figure is relatively perpendicular to the direction in which the film is fed in the direction D1, the holders Ci, Co, one of the grippers Ci first reaches the position B at the end of the extension of the film. At this time, the straight line connecting the grippers Ci and Co is inclined at an angle θ L with respect to a direction slightly perpendicular to the winding direction D2 of the film. Based on the above operation, the long film is formed to extend obliquely at an angle of θ L with respect to the width direction. Here, a slightly vertical system means falling within the range of 90 ± 1 °.

In the oblique stretching step, the film transport speed may be 1 to 150 m/min. The film transport speed is preferably from 10 to 120 m/min, more preferably from 20 to 100 m/min, from the viewpoint of improving the productivity of the film.

Next, the details of the above-described heating zone Z will be described. The heating zone Z of the extension 5 is constituted by a preheating zone Z1, an extension zone Z2 and a soothing zone Z3. In the extension portion 5, the film held by the holding members Ci and Co is sequentially passed through the preheating zone Z1. Stretch zone Z2, sooth zone Z3. In the present embodiment, the preheating zone Z1 and the extension zone Z2 are partitioned by the partition walls, and the extension zone Z2 and the soothing zone Z3 are partitioned by the partition walls. Further, in the region of each of the preheating zone Z1, the extension zone Z2, and the soothing zone Z3, a partition wall may be appropriately provided (the inside of each zone may be further divided by the partition wall).

The preheating zone Z1 is an area at the entrance of the heating zone Z, and the grippers Ci and Co holding the both ends of the film are held at a predetermined interval between the left and right (in the film width direction).

The extension zone Z2 is an area in which the distance between the grippers Ci and Co at both ends of the grip film is developed until a predetermined interval is reached. At this time, the general oblique extension is performed as described above, but the longitudinal direction or the lateral direction may be extended after the oblique extension before, depending on the necessity.

The soothing zone Z3 is a zone in which the stress (residual stress) remaining on the film due to the oblique extension is relieved by the temperature setting described later after the oblique stretching step in the extending region Z2. In the soothing zone Z3, since the optical axis (late phase axis) of the obliquely extending film is fixed, the soothing zone Z3 is also referred to as a heat fixing zone. In the soothing zone Z3, the grippers Ci and Co at both ends can be moved in parallel with each other, or can be walked in such a manner that the film is contracted in the width direction and then kept parallel. In any case, in the soothing zone Z3, the film transport path does not bend as in the obliquely extending region Z2-2, and the film transport direction is constant.

Further, after the stretched film passes through the soothing zone Z3, the temperature in the region may be set to a range (cooling region) equal to or lower than the glass transition temperature Tg (° C.) of the thermoplastic resin constituting the film.

Preferably, the temperature of the preheating zone Z1 is set to Tg~Tg+60°C with respect to the glass transition temperature Tg of the thermoplastic resin, and the temperature of the extension zone Z2 is set to Tg~Tg+50°C, soothing zone Z3 The temperature in the cooling zone was set to Tg-40~Tg+30 °C.

In addition, the lengths of the preheating zone Z1, the extension zone Z2, and the soothing zone Z3 may be appropriately selected. The length of the preheating zone Z1 is usually 50 to 200% with respect to the length of the extension zone Z2, and the length of the soothing zone Z3 is usually 50. ~150%.

Further, if the width of the film before stretching is set to Wo (mm), and the width of the film after stretching is set to W (mm), the stretching ratio R (W/Wo) in the extending step is Good is 1.1~3.0, better is 1.3~2.0. When the stretching ratio falls within this range, the thickness unevenness in the width direction of the film becomes small, which is preferable.

Further, the method of extending the slanting portion of the extending portion 5 is not limited to the above-described method, and the slanting extension may be performed by, for example, simultaneous biaxial stretching as disclosed in Japanese Laid-Open Patent Publication No. 2008-23775. In addition, the simultaneous biaxial stretching means that both end portions in the width direction of the long film to be supplied are gripped by the respective holders, and the long film is conveyed while moving the respective holders, and the long film is stretched. When the transport direction is set to a constant state, the long film is oriented to the width by changing the moving speed of one of the grippers to the moving speed of the other gripper. A method of extending toward an oblique direction. In addition to this, the oblique extension can be performed by a technique as disclosed in Japanese Laid-Open Patent Publication No. 2011-11434.

(Details of film cutting device)

Next, the details of the film cutting device 8 will be described. Fig. 3 is a perspective view showing a schematic configuration of the film cutting device 8. The film cutting device 8 has a first cutting portion 8a and a second cutting portion 8b, and the first cutting portion 8a and the second cutting portion 8b are long strips that are obliquely extended by the extending portion 5, respectively. Both end portions of the oblique alignment film F' in the width direction, that is, one end portion Ta and the other end portion Tb are cut along the longitudinal direction. By the first cutting portion 8a and the second cutting portion 8b, the end portion Ta and the other end portion Tb are cut and removed from the long inclined alignment film F', whereby the width direction can be obtained. The film portion (product portion) remaining between the end portion Ta and the end portion Tb serves as the optical film F. The cut ends Ta and Tb are collected as a trimming portion to a supply plate (not shown), and are reused in the subsequent film formation. Moreover, the position in the width direction of the first cutting portion 8a and the second cutting portion 8b is adjusted in accordance with the width of the obtained optical film F.

Fig. 4 is a plan view of the film cutting device 8. Each of the first cutting portion 8a and the second cutting portion 8b has an upper blade 10a (second blade) and a lower blade 10b (first blade). Lower blade 10b, the inclined line with respect to the alignment film strip F 'of the film plane is arranged on one side (e.g. lower side), and a rotation axis arranged along the width of the rotating blade rotation direction of the center 10b _1. The upper blade 10a is a rotary blade that is disposed on the other side (for example, the upper side) with respect to the film surface of the elongated oblique alignment film F'. The rotating shaft 10a _{1 of the} upper blade 10a is inclined in the film surface with respect to the width direction at an angle corresponding to the beam angle θ 1 (°) with respect to the lower blade 10b. Further, the above-mentioned toe angle refers to an angle formed by the upper blade 10a and the lower blade 10b in the film surface.

When the long inclined alignment film F' is transported to the film cutting device 8, the long inclined alignment film F' is attached to the position (cutting point) sandwiched by the upper blade 10a and the lower blade 10b, by the upper blade 10a And the rotation of the lower blade 10b is cut. The long inclined alignment film F' is cut while being conveyed in the longitudinal direction while the long oblique alignment film F' is cut, and the long oblique alignment film F' is cut along the longitudinal direction. In the film cutting device 8, the cutting step of cutting the both end portions in the width direction of the long oblique alignment film F' by the first cutting portion 8a and the second cutting portion 8b is performed. .

Here, in the above-described cutting step, the positional relationship between the upper blade 10a and the lower blade 10b is set as follows in each of the first cutting portion 8a and the second cutting portion 8b. The strip oblique alignment film F' is cut. That is, in one of the width direction of the lower blade 10b (for example, the film center side, the film inner side) and the other side (the side opposite to the film center side, the film outer side), with the bundle facing the lower blade 10b The direction in which the angle θ 1 increases increases the upper blade 10a, and the upper blade 10a is disposed on the side where the angle θ formed by the direction S of the upper blade 10a forming the beam angle θ 1 and the direction of the elongated oblique alignment film F' becomes smaller. 10a. Further, the above-described angle θ is set to a range of 0° < θ < 90°. In the example shown in Fig. 4, the above angle θ becomes small. The first cutting portion 8a that cuts the end portion Ta on the left side of the long obliquely oriented film F' is the film center side (the inside of the film) with respect to the lower blade 10b. The second cut portion 8b, which is cut at the end Tb on the right side of the inclined alignment film F', is opposite to the center side of the film (outside of the film) with respect to the lower blade 10b. In the cutting step, the upper blade 10a and the lower blade 10b are disposed as described above, and the long oblique alignment film F' is sandwiched, and the long oblique alignment film F' is cut.

Fig. 5 is a plan view of a film cutting device 8' of a reference example. The film cutting device 8' of the reference example is in the second cutting portion 8b, and the positional relationship between the lower blade 10b and the upper blade 10a in the width direction is opposite to that of the fourth figure. The same structure as the film cutting device 8 of Fig. 4. In other words, in the reference example, the upper cutting blade 10a is disposed on the center side of the film with respect to the lower blade 10b, and is disposed between the lower cutting blade 10b and the center of the film. The side forms a beam angle θ 1, and the upper obliquely directed film F' is sandwiched and cut by the upper blade 10a and the lower blade 10b. Further, the absolute value of the beam angle θ 1 is set to be the same in FIGS. 4 and 5 .

In the reference example, the direction of the surface S of the upper blade 10a in the second cutting portion 8b is a direction in which the direction of the alignment of the long oblique alignment film F' greatly intersects. At this time, if the alignment angle of the long oblique alignment film F' (the angle formed by the alignment direction with respect to the width direction) is set (°), in the film plane of the strip-shaped oblique alignment film F', the angle θ formed between the direction along the plane S and the alignment direction is θ=(90°- ) + θ 1. When the angle θ is large, the alignment of the elongated oblique alignment film F′ in the oblique direction is a large impedance when the second cutting unit 8 b is cut along the longitudinal direction. At the time of cutting, the long inclined alignment film F' is relatively easily slid toward the alignment direction with respect to the second cutting portion 8b (the upper blade 10a and the lower blade 10b). As a result, the cut state of the long inclined alignment film F' is deteriorated, and whiskers or fuzzing are generated at the end portion (cut portion), and the breakage of the optical film F is also likely to occur at the time of cutting. .

On the other hand, in the configuration of Fig. 4, both the first cutting portion 8a and the second cutting portion 8b are inclined in the direction of the surface S of the upper blade 10a in the film surface. The angle θ between the alignment directions of the alignment film F' is θ=(90°- ) - θ 1, which is smaller than the angle θ of Fig. 5 (reference example). That is, in the configuration of Fig. 4, in the width direction, the upper blade 10a is positioned closer to the alignment direction of the elongated oblique alignment film F' with respect to the lower blade 10b, so the above angle The θ system is smaller than the configuration of Fig. 5.

In this manner, since the upper blade 10a is positioned closer to the direction of the alignment direction and the long oblique alignment film F' is cut, the impedance of the elongated oblique alignment film F' due to the alignment in the oblique direction is obtained. It is smaller than the case of cutting by the configuration of Fig. 5, and it is possible to cut the oblique alignment film F' with respect to the first cutting portion 8a and the second cutting at the time of cutting. The portion 8b is relatively restrained from being bounced toward the alignment direction. As a result, the cut state of the long inclined alignment film F' is improved, and it is possible to suppress the occurrence of whiskers or fuzzing at the end portions, and also to suppress the breakage of the optical film F at the time of cutting. Furthermore, since the system can be tilted for long strips The alignment film F' is suppressed from being bounced in the alignment direction at the time of cutting, so that the tilting advancement of the optical film after the cutting can be suppressed, and the winding end faces when the optical film is taken up can be aligned with each other, and the roll can be rolled. Take the form to be good.

Further, the long obliquely oriented film of the present embodiment may be a long inclined body in which a long film is fed from a wound body of a long film which is wound and wound, and which is extended in a direction inclined with respect to the width direction. Extend the film. The above-described oscillating winding refers to a method of winding a film onto a winding core while causing at least one of the core or the film to periodically oscillate in the width direction. Such a wobble winding is performed for the purpose of reducing the agglomeration of the film to be wound up (the films are attached to each other) or the black band (the band in the circumferential direction). By.

The long film which is oscillated and wound is attached to the end portion in the width direction, and there is a slight variation in film thickness. The reason for this is that, in the winding state, the portion of the end portion of the long film that is beyond the winding core direction is not pressed by the upper and lower films, and the portion that enters the inner side of the winding core direction is up and down. Since the film is pressed, the presence or absence of such a press will appear as a difference in film thickness.

When the film thickness of the film to be cut is changed at the slitting point between the upper blade 10a and the lower blade 10b, the film thickness becomes more likely to be changed at the time of cutting. Bounces toward the alignment direction. Therefore, it is possible to obliquely align the strips at the time of cutting by the arrangement of the upper blade 10a and the lower blade 10b as shown in Fig. 4 In the cutting method of the embodiment in which the opening of the film F' in the direction of the alignment is suppressed and the cutting state is improved, the long obliquely oriented film is a strip which is obliquely extended by the long film which is oscillated and wound. The case of tilting the alignment film is very effective.

In addition, the alicyclic olefin polymer-based resin is weaker than the cellulose ester-based resin because it is low in brittleness, so that it is liable to be cut or fluffed in the cut portion, and is cut. The breaking of the optical film F is also likely to occur at the time of breaking. Therefore, the cutting method of the above-described embodiment in which the cutting state of the long inclined alignment film F' can be improved is such that the long obliquely oriented film contains the alicyclic olefin polymer resin and the strip is obliquely aligned to the film. It is very effective to cut both ends.

Further, the beam angle θ 1 shown in Fig. 4 may be appropriately set as long as it is between 0 ° < θ 1 < 1 °. Further, the angle θ 2 of the blade edge of the upper blade 10a may be appropriately set, for example, between 30° and 60°.

In addition, in the above, the first blade lower blade 10b is disposed such that the rotation axis 10b _{1 is} along the width direction, and the second blade upper blade 10a is set such that the rotation axis 10a _{1 is} opposed to Arranged in a manner of being inclined in the width direction, but conversely, the upper blade 10a is disposed such that the rotating shaft 10a _{1 is} along the width direction, and the lower blade 10b is oriented such that the rotating shaft 10b ₁ is opposite to the width Configure the direction and tilt. In other words, the upper blade 10a can be handled as the first blade, and the lower blade 10b can be handled as the second blade.

<Quality of long oblique alignment film>

In the strip-shaped oblique alignment film of the present embodiment, it is preferable that the alignment angle θ is inclined with respect to the winding direction in a range of, for example, more than 0° and less than 90°, and at least in a width of 1300 mm, and a width. The variation of the retardation Ro in the plane of the direction is 2 nm or less, and the deviation of the alignment angle θ is less than 0.6°. Further, the in-plane hysteresis value Ro (550) measured at a wavelength of 550 nm of the long oblique alignment film is preferably in the range of 80 nm or more and 160 nm or less, more preferably in the range of 90 nm or more and 150 nm or less.

In other words, in the long oblique alignment film of the present embodiment, the variation of the in-plane retardation Ro is 2 nm or less, preferably 1 nm or less, in at least 1300 mm in the wide direction. By setting the variation of the in-plane retardation Ro to the above range, a long optical film obtained by elongating the oblique alignment film and a polarizing element are bonded together to form a circular polarizing plate, and this is applied to an organic EL. In the case of the image display device, color unevenness due to leakage of external light reflected light during black display can be suppressed. In addition, when the optical film is used as, for example, a retardation film for a liquid crystal display device, the display quality can be improved.

Further, in the long oblique alignment film of the present embodiment, the difference in the alignment angle θ is less than 0.6° in the width direction of at least 1300 m, preferably less than 0.4°, and most preferably less than 0.2. °. When the optical film having a difference in the alignment angle θ of more than 0.6° is bonded to the polarizing element to form a circularly polarizing plate, and this is placed in an image display device such as an organic EL display device, light leakage occurs. There will be situations where the contrast between light and dark is reduced.

In-plane retardation of the long oblique alignment film of this embodiment Ro, according to the design of the display device used to select the optimum value. Further, the above Ro is a value obtained by multiplying the difference between the refractive index nx in the in-plane slow axis direction and the refractive index ny in the direction orthogonal to the in-plane and the late-phase axis by the average thickness d of the film ( Ro = (nx - ny) × d).

The average thickness of the elongated oblique alignment film of the present embodiment is from 1 to 400 μm, preferably from 10 to 200 μm, more preferably from 10 to 60 μm, particularly preferably from 15 to 45 μm, from the viewpoint of mechanical strength and the like.

The elongated oblique alignment film of this embodiment may also have a functional layer on the surface thereof. As the functional layer, an antireflection layer, a low refractive index layer, a hard coat layer, a light scattering layer, a light diffusion layer, an antistatic layer, a conductive layer, an electrode layer, a birefringent layer, a surface energy adjustment layer, a UV absorbing layer, A color material layer, a water resistant layer, a specific gas barrier layer, a heat resistant layer, a magnetic layer, an oxidation resistant layer, a protective coating, and the like.

<Circular polarizer>

In the circularly polarizing plate of the present embodiment, a polarizing plate protective film, a polarizing element, and a λ/4 film are laminated in this order, and a retardation axis of the λ/4 film and an absorption axis (or a transmission axis) of the polarizing element are formed. The angle is 45°. The λ/4 film can be formed by cutting an optical film (long obliquely extending film) obtained by cutting both ends of the long oblique alignment film of the present embodiment. In the case where the circularly polarizing plate of the present embodiment is used in an organic EL display device, the polarizing plate protective film, the polarizing element, and the λ/4 film are respectively corresponding to the protective film 313 and the polarizing element 311 of FIG. λ/4 film 316. In the present embodiment, it is preferably elongated A polarizing plate protective film, a long strip-shaped polarizing element, and a long strip-shaped λ/4 film are laminated in this order.

In the case where the circularly polarizing plate of the present embodiment is used in a liquid crystal display device, the polarizing plate protective film, the polarizing element, and the λ/4 film are respectively corresponding to the protective film 506 and the polarizing element 501 of FIG. λ/4 film 503. The protective film 506 and the polarizing element 501 are disposed on the outer side (visual identification side) of the display cell 401, and the λ/4 film 503 is disposed on the outer side (visual identification side) of the polarizing element 501. The linearly polarized light that is emitted from 401 and transmitted through the polarizing element 501 is converted into circularly polarized light or elliptically polarized light by the λ/4 film 503. Therefore, when the observer wears the polarized sunglasses and observes the displayed image of the display device 400, regardless of the angle at which the observation is made (regardless of the transmission axis of the polarizing element 501 (perpendicular to the absorption axis) What is the degree of shift of the transmission axis of the polarized sunglasses? The components of the light parallel to the transmission axis of the polarized sunglasses can be guided to the observer's eyes and observed to be displayed, and the observation can be suppressed. The angle makes it difficult to see the case where the portrait is displayed.

In the circularly polarizing plate of the present embodiment, a polarizing element can be produced by laminating a polyvinyl alcohol doped with iodine or a dichroic dye and bonding it with a λ/4 film/polarizing element. The film thickness of the polarizing element is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

The polarizing plate can be produced by a general method. The alkali-alkaline-treated λ/4 film is preferably one side of a polarizing element produced by immersing and stretching a polyvinyl alcohol-based film in an iodine-based solution. The solution was adhered with a fully alkalized aqueous polyvinyl alcohol solution.

The polarizing plate can be further formed by laminating a release film on the opposite surface of the polarizing plate protective film of the polarizing plate. The protective film and the release film are used for the purpose of protecting the polarizing plate during shipment of the polarizing plate or during product inspection.

<Organic EL display device>

Fig. 6 is a cross-sectional view showing a schematic configuration of an organic EL display device 100 as an OLED of the present embodiment. In addition, the configuration of the organic EL display device 100 is not limited to this.

The organic EL display device 100 is configured by forming a circularly polarizing plate 301 on the organic EL element 101 via the adhesion layer 201. The organic EL element 101 is composed of a metal electrode 112, a light-emitting layer 113, a transparent electrode (ITO or the like) 114, and a sealing layer 115, on a substrate 111 using glass or polyimide. In addition, the metal electrode 112 may also be formed by a reflective electrode and a transparent electrode.

The circular polarizing plate 301 is formed by laminating a λ/4 film 316, an adhesive layer 315, a polarizing element 311, an adhesive layer 312, a protective film 313, and a hardened layer 314 from the side of the organic EL element 101, and the polarizing element 311 is λ. The /4 film 316 is held by the protective film 313. The angle between the transmission axis of the polarizing element 311 and the slow axis of the λ/4 film 316 formed of the optical film of the present embodiment is about 45 (or 135). The circular polarizing plate 301 is formed by lamination.

In the above protective film 313, it is preferable to laminate and harden Layer 314. The hardened layer 314 not only has a function of preventing damage of the surface of the organic EL display device 100, but also has an effect of preventing warpage caused by the circular polarizing plate 301. Further, an anti-reflection layer may be formed on the hardened layer 314. The organic EL element 101 has a thickness of about 1 μm.

In the above-described configuration, when a voltage is applied to the metal electrode 112 and the transparent electrode 114, electrons are injected from the metal electrode 112 and the electrode serving as the cathode among the metal electrode 112 and the transparent electrode 114, and a hole is injected from the electrode serving as the anode. By recombining the two in the light-emitting layer 113, light emission of visible light rays corresponding to the light-emitting characteristics of the light-emitting layer 113 is generated. The light generated in the light-emitting layer 113 is directly or after being reflected by the metal electrode 112, and is taken out to the outside through the transparent electrode 114 and the circularly polarizing plate 301.

In an organic EL display device, a metal electrode, a light-emitting layer, and a transparent electrode are sequentially laminated on a transparent substrate to form an element (organic EL element) as an illuminant. Here, the light-emitting layer is a laminate of various organic thin films, and for example, a light-emitting layer formed of a triphenylamine derivative or the like and a fluorescent organic solid such as ruthenium are known. The laminate of the layers, or a laminate of such an emission layer and an electron injection layer made of an anthracene derivative or the like, or a laminate of the hole injection layer, the light-emitting layer, and the electron injection layer, etc. The composition of the combination.

An organic EL display device injects a hole and electrons into a light-emitting layer by applying a voltage to a transparent electrode and a metal electrode, and excites a fluorescent substance by energy generated by recombination between the holes and the electrons. And radiating light when the excited fluorescent substance returns to the basic state, According to this principle, light is emitted. The mechanism of recombination on the way is the same as that of a general diode. As a general matter, it can be inferred that the current and the intensity of light emission exhibit a nonlinearity accompanying the rectifying property with respect to the applied voltage.

In the organic EL display device, in order to extract the light emitted from the light-emitting layer, at least one of the electrode layers must be transparent, and a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is usually used as an anode. use. On the other hand, in order to facilitate electron injection and improve luminous efficiency, it is important to use a substance having a small work function in the cathode, and a metal electrode such as Mg-Ag or Al-Li is usually used.

In the organic EL display device having such a configuration, the light-emitting layer is formed by an extremely thin film having a thickness of about 10 nm. Therefore, the light-emitting layer also transmits light substantially completely in the same manner as the transparent electrode. As a result, when light is emitted from the surface of the transparent substrate and transmitted through the transparent electrode and the light-emitting layer during non-light-emitting, the light reflected on the metal electrode is again emitted toward the surface side of the transparent substrate, so that when visually recognized from the outside, the organic light is organic. The display surface of the EL display device looks like a mirror.

The circularly polarizing plate of the present embodiment is suitable for an organic EL display device in which light reflection is particularly problematic.

In other words, when the organic EL element 101 is not emitting light, external light incident from the outside of the organic EL element 101 by indoor illumination or the like is half absorbed by the polarizing element 311 of the circular polarizing plate 301. The remaining half is transmitted as a linearly polarized light and injected into the λ/4 film 316. Because the transmission axis of the polarizing element 311 and the λ/4 film are The retardation axes of 316 are arranged at 45[deg.] (or 135[deg.]) crossing so that the light incident into the λ/4 film 316 is converted into circularly polarized light by transmission through the λ/4 film 316.

When the circularly polarized light emitted from the λ/4 film 316 is specularly reflected by the metal electrode 112 of the organic EL element 101, the phase is inverted by 180 degrees and reflected as a reverse circularly polarized light. Since the reflected light is converted into linearly polarized light perpendicular to the transmission axis of the polarizing element 311 (parallel to the absorption axis) by being incident on the λ/4 film 316, the polarizing element 311 is completely absorbed, and is not Will be shot to the outside. In other words, by the circular polarizing plate 301, light reflection outside the organic EL element 101 can be reduced.

<Liquid crystal display device>

Fig. 7 is a cross-sectional view showing a schematic configuration of a display device 400 as a liquid crystal display device of the embodiment. The display device 400 is configured by arranging a polarizing plate 402 on one side of the display cell 401.

Further, in the case of a liquid crystal display device, the display cell 401 can be regarded as a liquid crystal cell in which a liquid crystal layer is held by a pair of substrates. Further, on the opposite side of the liquid crystal cell from the polarizing plate 402, another polarizing plate disposed in a state of being orthogonal to the polarizing plate 402 and a backlight for illuminating the liquid crystal cell are provided, but in FIG. In the middle, the illustrations of these are omitted.

Further, the display device 400 may have a front window 403 on the side opposite to the display cell 401 with respect to the polarizing plate 402. Front window 403 The display device 400 is provided with a cover member, for example, made of a cover glass. Between the front window 403 and the polarizing plate 402, a filler 404 made of, for example, an ultraviolet curable resin is filled. When the filler 404 is not present, since an air layer is formed between the front window 403 and the polarizing plate 402, there is a reflection of light at the interface between the front window 403 and the polarizing plate 402 and the air layer. The case where the visibility of the displayed image is lowered. However, according to the filler 404 described above, since the air layer is not formed between the front window 403 and the polarizing plate 402, it is possible to avoid a decrease in visibility of the display image due to reflection of light at the interface.

The polarizing plate 402 has a polarizing element 501 that transmits a predetermined linear polarized light. On one side of the polarizing element 501 (opposite to the display cell 401), a λ/4 film 503 and a hardened layer 504 made of an ultraviolet curable resin are laminated in this order via the adhesive layer 502. Further, on the other surface side (the side of the display cell 401) of the polarizing element 501, a protective film 506 is bonded via the adhesive layer 505.

The polarizing element 501 is obtained, for example, by dyeing a polyvinyl alcohol film with a dichroic dye and extending it at a high magnification. The polarizing element 501 is subjected to alkaline treatment (also referred to as alkalization treatment), and then the λ/4 film 503 is bonded to the one surface side via the adhesive layer 502, and the other layer side is bonded and protected via the adhesive layer 505. Film 506.

Next, the layers 502 and 505 are, for example, a layer formed of a polyvinyl alcohol adhesive (PVA adhesive, paste), but may be a layer formed of an ultraviolet curing type adhesive (UV adhesive). These adhesives are liquids when applied to the surface of the adhesive surface, by drying after coating or It is hardened by ultraviolet irradiation, and the two are followed. That is, the subsequent layers 502 and 505 are respectively connected to the λ/4 film 503, the polarizing element 501, and the protective film 506 by changing from the liquid state. In this way, the layers 502 and 505 are adhered to each other by the change from the state of the liquid, and the adhesive layer is adhered to the substrate. The flaky adhesive layer of the agent is different.

In the present embodiment, the λ/4 film 503 is a layer containing a cellulose resin (cellulose-based polymer). In addition, the λ/4 film 503 may contain a polycarbonate resin (polycarbonate polymer) instead of the cellulose polymer, and may also contain a cycloolefin resin (cycloolefin polymer). However, the λ/4 film 503 is preferably a cellulose-based polymer or a polycarbonate-based polymer from the viewpoint of chemical resistance.

The λ/4 film 503 is a λ/4 film of a film having a thickness of 10 μm to 70 μm. Further, the angle (crossing angle) between the slow axis of the λ/4 film 503 and the absorption axis of the polarizing element 501 is 30° to 60°, whereby the linear polarization from the polarizing element 501 is caused by The λ/4 film 503 is converted into circularly polarized or elliptically polarized light.

The hardened layer 504 (also referred to as a hard coat layer) is composed of an active energy ray-curable resin (for example, an ultraviolet curable resin).

The protective film 506 is composed of, for example, an optical film made of a cellulose resin (cellulose polymer), an acrylic resin, a cyclic polyolefin (COP), or a polycarbonate (PC). protection The film 506 is provided as a film for protecting the back side of the polarizing element 501, but may be provided as an optical film which can also serve as a retardation film having a desired optical compensation function.

Further, in the case of the liquid crystal display device, the polarizing plate disposed on the opposite side of the polarizing plate 402 with respect to the display cell 401 (liquid crystal cell) is held by the two optical films. In the above-described polarizing element and optical film, the same as the polarizing element 501 and the protective film 506 of the polarizing plate 402 can be used.

Here, the above-described polarizing element 501 and λ/4 film 503 may each be elongated. In this case, the retardation axis of the λ/4 film 503 is preferably 30° to 60° with respect to the longitudinal direction of the λ/4 film 503. In this case, the long λ/4 film 503 can be formed into a roll-shaped film which is formed by oblique stretching, and is attached to the roll-shaped polarizing element 501 by a so-called roll-to-roll method. In combination, a strip-shaped polarizing plate 402 is produced. Therefore, in the case where the polarizing plate 402 is produced by a batch type in which the film sheets are bonded one at a time, the productivity can be greatly improved, and the yield can be greatly improved.

Further, on the side of the adhesive layer 502 of the λ/4 film 503, an easy-adhesion layer for improving the adhesion of the λ/4 film 503 may be provided. The easy-adhesion layer is formed by performing an easy-on process on the adhesive layer 502 side of the λ/4 film 503. Although it is easy to carry out the treatment, there are corona (discharge) treatment, plasma treatment, flame treatment, ITRO treatment, glow treatment, ozone treatment, primer treatment, and the like, but at least one of them may be carried out. These are easy to handle, as far as productivity is concerned, as an easy connection The treatment is preferably corona treatment or plasma treatment.

<Example>

Hereinafter, the specific embodiments of the present invention are described, but the present invention is not limited by the embodiments. In addition, the following is a description of "parts" or "%", unless otherwise stated, these are "mass parts" or "% by mass".

[Production of Long Film 1]

The long film 1 was produced by the following method. Further, the long film 1 is a cellulose ester resin.

Microparticle Dispersion

The mixture was stirred and mixed by a dissolver for 50 minutes, and then dispersed by Manton Gaulin to prepare a fine particle dispersion 1.

Microparticle Addition Liquid

The fine particle dispersion was slowly added while sufficiently stirring in a dissolution tank filled with methylene chloride based on the following composition. Further, the secondary particles have a particle size of a predetermined size and are dispersed by a grinder. This was filtered by FINE MET NF manufactured by Nippon Seisaku Co., Ltd. to prepare a fine particle addition liquid 1.

"Doping Modulation"

A dopant of the following composition is prepared. First, dichloromethane and ethanol were added to the pressure dissolution tank. Next, the cellulose acetate was charged while stirring in a pressure-dissolving tank filled with a solvent. This was heated, and the mixture was completely dissolved while stirring, and then filtered using an filter paper No. 244 made of a filter paper (manufactured) to prepare a main dope. Thereafter, the main dope and each material are placed in a sealed container so as to have a ratio described below, and the dopant is dissolved while stirring to prepare a dopant. Further, as the sugar ester compound and the ester compound, a compound synthesized by the following synthesis examples is used.

"Composition of dopants"

"Synthesis of sugar ester compounds"

The sugar ester compound is synthesized by the following steps.

In a four-necked flask equipped with a stirring device, a reflux condenser, a thermometer, and a nitrogen introduction tube, 34.2 g (0.1 mol) of sucrose, 180.8 g (0.6 mol) of benzoic anhydride, and 379.7 g of pyridine (4.8 mol) were charged. The mixture was heated while bubbling nitrogen gas introduced from the nitrogen gas introduction tube while stirring, and the esterification reaction was carried out at 70 ° C for 5 hours.

Next, the pressure in the flask was reduced to 4 × 10 ² Pa or less, and the excess pyridine was distilled off at 60 ° C, and then the pressure in the flask was reduced to 1.3 × 10 Pa or less, and the temperature was raised to 120 ° C to distill off the benzoic anhydride. Most of the benzoic acid produced.

Finally, 100 g of water was added to the toluene layer to be separated, and the mixture was washed with water at normal temperature for 30 minutes. Thereafter, the toluene layer was separated, and toluene was distilled off at 60 ° C under reduced pressure (4 × 10 ² Pa or less). A mixture of the compounds A-1, A-2, A-3, A-4 and A-5 (sugar ester compound) was obtained.

As a result of analyzing the obtained mixture by HPLC and LC-MASS, A-1 was 1.3% by mass, A-2 was 13.4% by mass, A-3 was 13.1% by mass, and A-4 was 31.7% by mass. A-5 was 40.5 mass%. The average degree of substitution is 5.5.

"Determination conditions of HPLC-MS" 1) LC department

Device: Japan spectrophotometer (JASCO CO-965), detector (JASCO UV-970-240nm), pump (JASCO PU-980), degassing machine (JASCO DG-980-50)

Column: Inertsil ODS-3 particle size 5μm 4.6×250mm (GL Sciences system

Column temperature: 40 ° C

Flow rate: 1ml/min

Mobile phase: THF (1% acetic acid): H ₂ O (50:50)

Injection volume: 3μl

2) MS Department

Device: LCQ DECA (Thermo Quest (manufactured by Thermo Quest)

Ionization method: electrospray ionization (ESI) method

Spray Voltage: 5kV

Capillary temperature: 180 ° C

Vaporizer temperature: 450 ° C

"Synthesis of Ester Compounds"

The ester compound is synthesized by the following steps.

251 g of 1,2-propanediol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid, and 0.191 g of tetraisopropyl titanate as an esterification catalyst were placed in a thermometer, a stirrer, and a buffer. In a 2-L four-necked flask of a cooling tube, the temperature was raised to 230 ° C while slowly stirring in a nitrogen gas stream. The dehydration condensation reaction was carried out for 15 hours, and after completion of the reaction, the unreacted 1,2-propanediol was distilled off under reduced pressure at 200 ° C to obtain an ester compound. An ester compound having benzoic acid at the end of a polyester chain formed by condensing 1,2-propanediol, phthalic anhydride, and adipic acid Ester. The ester compound had an acid value of 0.10 and a number average molecular weight of 450.

Film making

Next, the dopant was uniformly cast on the support made of the stainless steel conveyor belt using an endless belt casting device. Next, the solvent was evaporated on the support until the amount of residual solvent in the tape formed by casting (casting) was 75%, and the tape was peeled off from the support, and then transferred by a plurality of rolls. The drying was completed to obtain a long film 1 having a width of 1500 mm and a film thickness of 50 μm. The manufactured long film 1 is wound by linear winding by a winding device, and is wound by a winding device after being wound once in the width direction. . When the long film 1 is wound in a straight line, the winding is performed in a roll state 1, and the wound film 2 is wound by winding the long film 1 in a wrap.

[Production of Long Film 2]

The long film 2 was produced by the following method. Further, the long film 2 is an alicyclic olefin polymer resin (COP resin).

In a nitrogen atmosphere, 1.2 parts of 1-hexene, 0.15 parts of dibutyl ether, and 0.30 parts of triisobutylaluminum were charged into a reactor at room temperature in 500 parts of cyclohexane after dehydration, and mixed. While maintaining the temperature at 45 ° C, it was added continuously for 2 hours from the tricyclo [4.3.0.12,5]癸-3,7-diene (dicyclopentadiene, hereinafter, abbreviated as DCP) 20 parts, 1, 4 -methyl-1,4,4a,9a-tetrahydroanthracene (hereinafter, abbreviated as MTF) 140 parts, and 4-methyl-tetracyclo[4.4.0.12, 5.17,10]-dodec-3-ene (hereinafter abbreviated as MTD) 40 parts of a decene-based monomer mixture, and tungsten hexachloride ( 40 parts of a 0.7% toluene solution and polymerization was carried out. 1.06 parts of butyl epoxidized propyl ether and 0.52 parts of isopropyl alcohol were added to the polymerization solution to inertize the polymerization catalyst to stop the polymerization reaction.

Then, 270 parts of cyclohexane was added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and further, 5 parts of a nickel-alumina catalyst (manufactured by Nippon Chemical Co., Ltd.) was added as a hydrogenation catalyst, and The hydrogen was pressurized to 5 MPa, and the mixture was heated to a temperature of 200 ° C while stirring, and then reacted for 4 hours to obtain a reaction solution containing 20% of a DCP/MTF/MTD ring-opening polymer hydrogenated polymer. After the hydrogenation catalyst was removed by filtration, a soft polymer (manufactured by KURARAY Co., Ltd.; SEPTON 2002) and an antioxidant (manufactured by Ciba Specialty Chemicals Co., Ltd.; IRGANOX 1010) were separately added to the obtained solution and dissolved (both of them). The polymer was 0.1 part per 100 parts).

Next, cyclohexane and other volatile components as a solvent are removed from the solution using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.), and the hydrogenated polymer is extruded from the extruder into a strand in a molten state. It is shaped and is ingot after cooling to be recovered. The result of calculating the copolymerization ratio of each of the norbornene-based monomers in the polymer from the residual norbornene composition (obtained by gas chromatography) in the solution after polymerization was DCP/MTF/MTD=10. /70/20, which is approximately equal to the composition loaded. The ring-opening polymer hydride has a weight average molecular weight (Mw) of 31,000, a molecular weight distribution (Mw/Mn) of 2.5, and a hydrogenation rate of 99.9%. The Tg was 134 °C. The ingot of the obtained hydrogenated ring-opening polymer was dried at 70 ° C for 2 hours using a hot air dryer through which air was passed, to remove moisture.

Next, the ingot was subjected to a short-axis extruder having a T-die of a coat hanger type (manufactured by Mitsubishi Heavy Industries Co., Ltd.: a screw diameter of 90 mm, a T-die lip material made of tungsten carbide, and a molten resin) The peeling strength was 44 N), and the melt-extrusion molding was carried out to produce a long film 2 (film thickness: 30 μm) as a cycloolefin polymer film. The extrusion molding was carried out in a clean room of 10,000 or less, and was carried out under the molding conditions of a molten resin temperature of 240 ° C and a T-die temperature of 240 ° C. The manufactured long film 2 is wound by a winding device in a straight line, and is wound up by a winding device after being wound in the width direction. . The winding film 3 is wound in a straight line for winding the long film 2, and the winding body 4 is obtained by winding the long film 2 in a wobble.

[Optical film 1]

The wound body 1 (linearly wound) of the long film 1 made of a cellulose ester resin is attached to the film feeding portion 2 of the manufacturing apparatus 1 of Fig. 1 and is long from the film feeding portion 2 The strip film 1 is fed out, supplied to the extending portion 5, and stretched obliquely to obtain a long oblique alignment film (long obliquely extending film) 1. At this time, in the extension portion 5, the alignment angle of the film is made (An angle formed between the late phase axis and the width direction) is slightly 45°, and the tilting is performed. The conveying speed of the film at this time was set to 15 m/min. Further, the film thickness of the elongated oblique alignment film 1 was 35 μm.

Next, the elongated oblique alignment film 1 obtained by the oblique extension of the extending portion 5 is supplied to the film cutting device 8 shown in Fig. 4, and the two strips are obliquely aligned to the width direction of the film 1. The end portion was cut to obtain the optical film 1 which was a product portion. Further, in the film cutting device 8 of Fig. 4, the toe angle θ1 is set to 0.01° on the IN side (inside of the film) in the first cutting portion 8a, and is on the OUT side in the second cutting unit 8b. The outer side of the film was set to 0.01°, and the angle θ 2 was set to 40°. The obtained optical film 1 is wound up on a winding core by a film take-up portion 9.

[Optical film 2]

The wound body 2 (swing wrap) of the long film 1 made of a cellulose ester resin is attached to the film feed portion 2, and the long film 1 is fed out, and the stretched portion 5 is used to perform oblique extension. Then, the long oblique alignment film 2 is obtained, and then the both ends of the film are cut by the film cutting device 8 of Fig. 4, and the optical film 2 serving as the product portion is obtained. Other than that, it is the same as that of the optical film 1.

[Optical film 3]

The wound body 3 of the long film 2 made of the COP resin (for linear winding) is attached to the film feeding portion 2, and the long film 2 is fed out, and the extending portion 5 is obliquely extended to obtain The strip is inclined to the alignment film 3, and then the ends of the film are separated by the film cutting device 8 of Fig. 4. The part is cut, and the optical film 3 which becomes a product part is acquired. Other than that, it is the same as that of the optical film 1.

[Optical film 4]

The wound body 4 (swing wrap) of the long film 2 made of the COP resin is attached to the film feeding portion 2, and the long film 2 is fed out, and the extending portion 5 is obliquely extended to obtain After the long film is inclined to the alignment film 4, the film cutting device 8 of Fig. 4 cuts both end portions of the film to obtain the optical film 4 serving as the product portion. Other than that, it is the same as that of the optical film 1.

[Optical film 5]

The wound body 1 of the long film 1 made of a cellulose ester resin (for linear winding) is attached to the film feeding portion 2, and the long film 1 is fed out, and the extending portion 5 is obliquely extended. Then, the long oblique alignment film 5 is obtained, and then the both ends of the film are cut by the film cutting device 8' of Fig. 5, and the optical film 5 serving as the product portion is obtained. Other than that, it is the same as that of the optical film 1. Further, in the film cutting device 8' of Fig. 5, the toe angle θ1 is set to -0.01° on the IN side (inside of the film) in the first cutting portion 8a and the second cutting portion. The angle θ 2 is set to 40°.

[Optical film 6]

Winding body 2 of long film 1 made of cellulose ester resin (Swing wrap), attached to the film feeding portion 2, and the long film 1 is fed out, and the extending portion 5 is obliquely extended to obtain the long oblique alignment film 6, and then, by the fifth figure The film cutting device 8' cuts both end portions of the film to obtain the optical film 6 which is a product portion. Other than that, it is the same as that of the optical film 5.

[Optical film 7]

In the production of the optical film 1, the beam angle θ1 is set to 0.5° on the IN side (inside of the film) in the first cut portion 8a, and is on the OUT side (outside the film) in the second cut portion 8b. Set to 0.5° and the angle θ 2 is set to 40°. Other than this, the optical film 7 was obtained in the same manner as the production of the optical film 1.

[Evaluation] (must)

The presence or absence of the whisker-like fibrous foreign matter was visually observed at both end portions (cut portions) of the respective optical films 1 to 6, and the state of both end portions was evaluated based on the following criteria.

Evaluation Benchmark

○: No need.

×: There is a need.

(fluff)

At both ends of each of the optical films 1 to 6, the hair was observed by visual observation. Whether or not there is, and the status of both ends is evaluated based on the following criteria.

Evaluation Benchmark

○: No fluffing.

×: There is fluffing.

(cutting state)

The both end portions of each of the optical films 1 to 6 were visually observed, and the quality of the cut state was evaluated based on the following criteria.

Evaluation Benchmark

○: The cutting state is quite good without breaking.

△: The cutting state was substantially good without breaking.

×: The cutting state is bad, and there is a break.

Table 1 shows the results of evaluation for each of the optical films 1 to 6. In addition, in Table 1, CE means a cellulose ester type resin, and COP means an alicyclic olefin polymer type resin.

According to Table 1, it can be seen that in the optical films 5 and 6, at least the fluffing was confirmed at the end portion, and the cut state of the end portion was also poor, whereas in the optical films 1 to 4 and 7, There is no need for the end of the hair to occur, and the cutting state of the end can also give a generally good result. It is presumed that the reason is that when the optical films 1 to 4 and 7 are obtained, the blade 10a of the film cutting device 8 is positioned closer to the alignment direction with respect to the lower blade 10b, and the long inclination is cut. Since the alignment film F' is disposed, the impedance of the elongated oblique alignment film F' at the time of cutting due to the alignment in the oblique direction becomes small, and the long oblique alignment film F' becomes difficult to be bounced at the time of cutting. As a result, the cutting state is increased, and the occurrence of hairiness or fuzzing is suppressed.

Further, when the long film which is oscillated and wound is obliquely stretched, and the both end portions of the film are cut, the film thickness is changed by the influence of the film thickness variation caused by the wobble winding. It is easy to bounce toward the alignment direction as previously stated. However, it is presumed that the film is cut by the film cutting device 8 having the configuration shown in Fig. 4, and since the film opening direction of the film in the alignment direction is suppressed, the optical films 2, 4 are cut. The deterioration is suppressed to a minimum, and the cutting state can be maintained substantially good. Therefore, the method of cutting the film by using the film cutting device 8 of Fig. 4 can be said to be particularly the case where the both ends of the film are cut after the elongated film which is oscillated and wound is obliquely extended. very effective.

Further, since the COP resin is more fragile than the cellulose ester-based resin, it is liable to cause whisking or fuzzing at the time of cutting, and is also prone to cut. In the case of breaking the time, the results of the optical films 3 and 4 containing the COP resin are the same as those of the optical films 1 and 2 containing the cellulose ester resin. Therefore, it can be said that the film cutting device of Fig. 4 is used. The method of cutting the film is particularly effective in the case where the both ends of the long oblique alignment film containing the COP resin are cut.

Further, as a result of the optical films 1 and 7, as the beam angle θ 1 increases, the evaluation of the cutting state is deteriorated in one stage. Therefore, it can be said that the beam angle θ 1 is preferably as small as possible.

In addition, in the above description, although the alignment angle is An example in which the oblique alignment film is cut off slightly 45° is described, but it is confirmed that even the alignment angle The angle similar to that of the present embodiment can be obtained at an angle other than 45°, and the same effects as those of the embodiment can be obtained.

In the above description, an example in which a long oblique alignment film including a cellulose ester resin or a COP resin is used has been described. However, it has been confirmed that other resins (for example, polycarbonate resins, When the long oblique alignment film of the acrylic resin is used as the object to be cut, the same effect as that of the present embodiment can be obtained by using the cutting method similar to that of the present embodiment.

The method and apparatus for producing an optical film of the present embodiment described above can be expressed as follows.

1. A method for producing an optical film, comprising: a cutting step of cutting both end portions in a width direction of a long oblique alignment film by a first cutting portion and a second cutting portion, wherein the long inclination Alignment film The alignment direction of the film in the width direction is inclined, and the remaining portion of the long oblique alignment film is the optical film, and the first cutting portion and the first portion are Each of the cutting portions includes a first blade and a second blade, and the first blade is disposed on one side of the film surface of the long oblique alignment film, and the rotation axis is disposed along the width direction; a knife disposed on the other side of the film surface, wherein the rotation axis is inclined with respect to the width direction at an angle corresponding to a toe angle of the first blade in the film surface; and in the cutting step, Each of the first cutting portion and the second cutting portion increases in a direction toward a toe angle with respect to the first blade in one side and the other side in the width direction of the first blade. The second blade is inclined, and the second blade is disposed on a side where the angle formed by the surface of the second blade forming the toe angle and the alignment direction of the long oblique alignment film is small, and the first blade and the first blade are used. The aforementioned second knife will be long The strip oblique alignment film is clamped and cut.

2. The method for producing an optical film according to the above 1, wherein the long oblique alignment film is obtained by feeding the long film from a wound body of a long film which is oscillated and wound, and then A long obliquely extending film extending in a direction oblique to the width direction.

3. The method for producing an optical film according to the above 1 or 2, The long obliquely oriented film contains an alicyclic olefin polymer resin.

4. An apparatus for producing an optical film, comprising: a first cutting portion and a second cutting portion that cut both end portions in a width direction of a long oblique alignment film, wherein the long oblique alignment film is in a film surface The alignment direction with respect to the width direction is inclined, and the portion remaining after the both end portions are cut out of the long oblique alignment film is an optical film, and the first cutting portion and the second cutting portion are characterized. The first blade and the second blade are disposed, and the first blade is disposed on one side of the film surface of the long oblique alignment film, and the rotation axis is disposed along the width direction; and the second blade is disposed On the other side of the film surface, the rotation axis is inclined with respect to the width direction at an angle corresponding to the toe angle of the first blade in the film surface, and between the first blade and the first blade The long oblique alignment film is sandwiched and cut, and each of the first cutting portion and the second cutting portion is opposite to the other side in the width direction of the first blade. Increased beam angle of the first knife In the direction, the second blade is inclined, and the second blade is disposed on a side where the angle formed by the surface of the second blade forming the toe angle and the alignment direction of the long oblique alignment film is small.

[Industrial availability]

The present invention can be utilized in a liquid crystal display device In the manufacture of optical films in polarizing plates.

1‧‧‧ manufacturing equipment

2‧‧‧Film delivery department

3‧‧‧Transfer Direction Change Department

4‧‧‧ Guide roller

5‧‧‧Extension

6‧‧‧ Guide roller

7‧‧‧Transfer Direction Change Department

8‧‧‧Film cutting device

9‧‧‧ Film Reeling Department

Claims (6)

A method for producing an optical film, comprising: a cutting step of cutting both end portions in a width direction of a long oblique alignment film by a first cutting portion and a second cutting portion, wherein the elongated oblique alignment film The alignment direction of the film surface with respect to the width direction is inclined, and the portion remaining after the both end portions are cut out of the long oblique alignment film is an optical film, and the first cutting portion and the aforementioned Each of the second cutting portions includes a first blade and a second blade, and the first blade is disposed on a side of the film surface of the long oblique alignment film, and the rotation axis is disposed along the width direction; a two-knife disposed on the other side of the film surface, wherein the rotation axis is inclined with respect to the width direction at an angle corresponding to a toe angle of the first blade in the film surface; Each of the first cutting portion and the second cutting portion increases in a beam angle with respect to the first blade in one side and the other side in the width direction of the first blade. Direction will be the second knife Inclining, the second blade is disposed on a side where the angle formed by the surface of the second blade forming the toe angle and the direction of the alignment of the long oblique alignment film is small, and the first blade and the second blade are used The aforementioned elongated oblique alignment film is sandwiched and cut. The method for producing an optical film according to claim 1, wherein The long obliquely oriented film is a long obliquely stretched film which is formed by winding a long film from a wound body of a long film which is wound and wound, and then extending in a direction inclined with respect to the width direction. The method for producing an optical film according to the above aspect of the invention, wherein the long obliquely oriented film contains an alicyclic olefin polymer resin. The method for producing an optical film according to the first or second aspect of the invention, wherein the defect having a diameter of 5 μm or more in the film surface is 1/10 cm square or less. The optical film manufacturing apparatus includes a first cutting portion and a second cutting portion that cut both end portions in the width direction of the long oblique alignment film, and the long oblique alignment film is opposed to the film surface in the film surface. The alignment direction in the width direction is inclined, and the remaining portion of the long oblique alignment film is the optical film, and the first cutting portion and the second cutting portion respectively include In the first blade and the second blade, the first blade is disposed on one side of the film surface of the long oblique alignment film, and the rotation axis is disposed along the width direction; and the second blade is disposed on the first blade On the other side of the film surface, the rotation axis is inclined with respect to the width direction at an angle corresponding to the toe angle of the first blade, and the length is set between the first blade and the first blade. Each of the first cutting portion and the second cutting portion is in the one side and the other side in the width direction of the first blade, and is opposite to each other in the first cutting portion and the second cutting portion. The second blade is inclined in a direction in which the toe angle of the first blade is increased, and is disposed on a side where the angle formed by the surface of the second blade forming the toe angle and the alignment direction of the long oblique alignment film is small. The second knife mentioned above. The apparatus for producing an optical film according to claim 5, wherein the defect having a diameter of 5 μm or more in the surface of the film is 1/10 cm square or less.