KR20170103935A - Method for producing oblique stretched film - Google Patents

Abstract

A method of producing an obliquely-drawn film is characterized in that both ends in the width direction of the film are gripped by a pair of gripping portions, one of the waveguide segments is relatively advanced, the other waveguide segment is relatively delayed to transport the film, And an oblique stretching step of stretching the film in an oblique direction with respect to the width direction by bending the transport path on an arc. In the oblique stretching process, the temperature of the film at the end point of the bending of the arc on the conveying path for stretching in the oblique direction is made lower than the starting point of bending.

Description

Method for producing oblique stretched film

The present invention relates to a method for producing a warp stretched film in which a film is stretched in an oblique direction with respect to a width direction.

2. Description of the Related Art Conventionally, a self-emission type display device such as an organic EL (Electro-Luminescence) display device which is also called an OLED (Organic light-Emitting Diode) attracts attention. In the OLED, since a reflector such as an aluminum plate is provided on the back side of the display in order to increase the light extraction efficiency, the external light incident on the display is reflected by the reflector, thereby lowering the contrast of the image.

Therefore, in order to improve the contrast of light and shade by preventing the reflection of external light, it is known that a circular polarizer is formed by joining a stretched film and a polarizer, and this circular polarizer is disposed on the surface side of the display. At this time, the circularly polarizing plate is formed by bonding the polarizer and the stretched film so that the in-plane slow axis in the stretched film is inclined at a desired angle with respect to the transmission axis of the polarizer.

However, a general polarizer (polarizing film) is obtained by stretching at a high magnification in the longitudinal direction, and its transmission axis coincides with the width direction. Further, the conventional retardation film is produced by longitudinal stretching or transverse stretching, and in principle, the slow axis in the plane is at 0 ° or 90 ° with respect to the longitudinal direction of the film. Therefore, in order to incline the transmission axis of the polarizer and the slow axis of the stretched film at a desired angle as described above, it is not necessary to employ a batch type in which the long polarizing film and / or the stretched film are cut at a specific angle and the film pieces are bonded one by one And productivity was deteriorating.

On the other hand, when the film is stretched in the direction of the desired angle (in the oblique direction) with respect to the longitudinal direction, and the direction of the slow axis is set to be longer than that of the long oblique stretched film Various manufacturing methods have been proposed. For example, in the manufacturing method of Patent Document 1, the resin film is unwound from a direction different from the film winding direction after stretching, and both ends of the resin film are gripped and transported by the pair of wave earths. By changing the conveying direction of the resin film in the middle, the resin film is stretched in the oblique direction. Thereby, a long oblique stretched film having a slow axis at a desired angle exceeding 0 DEG and less than 90 DEG with respect to the longitudinal direction is produced.

By using such a long oblique stretched film, it is possible to produce a circular polarizer plate by joining a long polarizer film and a long obliquely stretched film by a roll-to-roll method, and the productivity of the circular polarizer plate is remarkably improved.

However, in recent years, there is a growing demand for large-sized and high-precision OLEDs, and it is increasingly demanded to reduce variations in optical characteristics of obliquely stretched films applied to circularly polarizing plates of OLEDs. In view of this point, in the above-described Patent Document 1, in order to reduce variations in optical characteristics, a film having a film thickness varied in the width direction is prepared in advance and the film is subjected to oblique stretching, So that it is attempted to equalize.

In addition, for example, in Patent Document 2, when a warp stretched film is stretched by stretching a long film stretched in the width direction (transverse stretching) in an oblique direction, the retardation value expressed by the transverse stretching is changed by the temperature at the time of oblique stretching It is disclosed that it is preferable to lower the stretching temperature at the time of oblique stretching more than the stretching temperature at the transverse stretching, from the viewpoint of preventing the stretching from becoming difficult to be expressed as a total retardation value. As a method of oblique stretching, there has been proposed a method in which oblique stretching is performed using a bent tenter rail in addition to a method of simultaneously stretching a long film in the transverse direction and the longitudinal direction (simultaneous biaxial stretching).

JP-A-2010-173261 (claim 1, paragraphs 0006, 0010, 1 to 4, etc.) Japanese Patent Laid-Open Publication No. 2013-97216 (see claim 1, paragraphs [0013], [0017], [0022], etc.)

It has been found that when OLEDs that are required to have a higher contrast than the liquid crystal display device use an oblique stretched film as described in Patent Document 1 or 2, there is a difference in color sensitivity between OLEDs. Investigation of this cause revealed that the in-plane retardation Ro was uneven in the longitudinal direction (conveying direction) of the obliquely drawn film, and this unevenness was a cause of color heterogeneity in the OLED. The reason why the non-uniformity of the in-plane retardation Ro in the longitudinal direction of the obliquely-drawn film occurs is presumed as follows.

In the bending type warp and stretch device disclosed in Patent Document 1 or 2, both ends in the width direction of the film are held by a pair of gripping portions, one of the wave segments is relatively advanced, and the other wave segment is relatively delayed The film is transported. Then, the film is bent in a circular arc in the middle of the conveying path of the film, whereby the film is stretched in the oblique direction with respect to the width direction. At this time, as shown in Fig. 23, in the section where oblique stretching is performed, that is, in the section from the beginning to the end of the bending of the arc on the conveying path, in the region of large curvature, So that it takes a decreasing behavior in the width direction. As a result, the stress of the film is lowered (= easier to relax in the width direction), so that the film becomes less tense and the film is more likely to vibrate. When the film is conveyed while being vibrated, the distance between the heating portion for heating the film upon stretching and the film is changed in the conveying direction. Therefore, as shown in Fig. 24, the in-plane retardation Ro of the film is varied in the conveying direction . As a result, when the formed obliquely drawn film is applied to an OLED, it is considered that color unevenness occurs.

In Patent Document 2, stretching temperatures are differentiated between transverse stretching and oblique stretching in order to promote the development of the retardation value. However, the shrinking behavior of the film in the transverse direction in the section where oblique stretching is performed is not mentioned at all And there is no disclosure at all of suppressing the lowering of the film tension due to the shrinkage behavior in the oblique stretching section and the vibration of the film.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide an OLED display device capable of reducing unevenness of in-plane retardation in the transport direction of a film even when oblique stretching is performed by bending a conveying path, And a method of manufacturing an oblique stretched film capable of reducing color unevenness when applied.

The above object of the present invention is achieved by the following constitution.

A method of producing an obliquely-drawn film according to one aspect of the present invention is a method of manufacturing an obliquely-drawn film, characterized in that both ends in the width direction of the film are held by a pair of gripping portions, And an oblique stretching step of stretching the film in an oblique direction with respect to the width direction by bending the transport path of the film in an arc shape,

In the warp stretching step, the temperature of the film at the end of bending of the arc on the conveying path for stretching in the oblique direction is made lower than the starting point of the bending.

In the oblique stretching process, since the temperature of the film at the end of bending of the arc on the conveying path is lower than the starting point of bending, the tension of the film can be stabilized in the bending period. That is, as the oblique stretching progresses in the above-mentioned bending period, the stretchability of the film can be stabilized by lowering the temperature in accordance with the lowering of the stretching magnification in the width direction by using the shrinking behavior of the film itself at low temperature. Thereby, the vibration of the film at the time of oblique stretching can be reduced, and occurrence of non-uniformity of in-plane retardation in the conveying direction can be reduced. As a result, even when the obliquely-drawn film thus produced is applied to a circularly polarizing plate for preventing reflection of external light of the organic EL display (OLED), unevenness in color due to unevenness of in-plane retardation in the conveying direction can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view schematically showing a schematic configuration of an apparatus for producing an obliquely-drawn film according to an embodiment of the present invention. FIG.
2 is a plan view schematically showing an example of a rail pattern of a stretching portion of the manufacturing apparatus.
3 is an explanatory view schematically showing a state in which the conveying path of the film in the stretching portion is bent in the middle.
Fig. 4 is an explanatory view showing another example of the manner of the drawing section. Fig.
5 is an explanatory diagram schematically showing an example of temperature control in the film transport direction of the stretching portion.
6 is a graph showing an example of a change in the film temperature.
7 is an explanatory view schematically showing another example of the temperature control in the elongating portion.
8 is an explanatory view schematically showing another example of the temperature control in the elongating unit.
Fig. 9 is an explanatory view showing an example of the arrangement of the heating section in the elongating section. Fig.
10 is an explanatory diagram showing another example of the arrangement of the heating section in the elongating section.
11 is a perspective view showing another configuration of the heating unit.
12 is a plan view of the heating unit of Fig.
Fig. 13 is an explanatory view showing an example of the arrangement of the heating section in Fig. 11 in the stretching section. Fig.
FIG. 14 is an explanatory view showing a state before the arrangement position of the equipment section of the elongating section is adjusted.
Fig. 15 is an explanatory view showing a state after adjustment of the arrangement position of the equipment part of the elongating part. Fig.
Fig. 16 is an explanatory diagram showing the temperature distribution before the evacuation adjustment in the furnace of the elongating section. Fig.
Fig. 17 is an explanatory view showing the temperature distribution after the exhaust adjustment in the furnace of the elongating section. Fig.
18 is a cross-sectional view showing a schematic configuration of an organic EL image display apparatus to which an obliquely stretched film produced by the above production apparatus is applied.
19 is a cross-sectional view showing a schematic structure of a liquid crystal display device to which the oblique stretched film is applied.
20 is an explanatory view showing an example of the temperature distribution in the film transport direction in the stretching portion.
21 is an explanatory diagram showing another example of the temperature distribution.
22 is an explanatory view showing another example of the temperature distribution.
Fig. 23 is an explanatory view schematically showing a state of bending of the conveying path at the time of oblique drawing.
24 is a graph showing variations in in-plane retardation in the transport direction of the film.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the present specification, when numerical ranges are denoted by A to B, values of lower limit A and upper limit B are included in the numerical range.

The method for producing a long obliquely drawn film according to the present embodiment is a method for producing a long obliquely drawn film in which a long oblong stretched film comprising a thermoplastic resin is stretched in an oblique direction with respect to the transverse direction and the longitudinal direction to produce a long obliquely stretched film Method.

The orientation direction of the long oblong stretched film, that is, the direction of the slow axis, is a direction in which the angle is greater than 0 DEG and less than 90 DEG with respect to the width direction of the film in the film plane (plane perpendicular to the thickness direction) The direction of the film automatically becomes longer than 0 ° and less than 90 ° with respect to the longitudinal direction of the film). Since the slow axis is usually expressed in a stretching direction or a direction orthogonal to the stretching direction, a long oblique stretched film having such a slow axis is produced by stretching in a direction exceeding 0 DEG and less than 90 DEG with respect to the width direction of the film . The angle formed by the width direction of the long oblong stretched film and the slow axis, that is, the orientation angle can be arbitrarily set at a desired angle in a range of more than 0 DEG and less than 90 DEG.

In the present embodiment, the term "long" means that the film has a length of at least about 5 times or more, preferably 10 times or more, more preferably at least about 5 times the width of the film. Specifically, (Film roll).

The long warp stretched film may be produced by winding a long unoriented film on a winding core to form a wound body (raw film), and supplying the raw film to the oblique stretching step from the wound body, It is also possible to continuously supply the film to the oblique stretching step from the film forming step without winding the long film. The film-forming step and the oblique stretching step are preferably carried out continuously because the desired film-elongated film can be obtained by feeding back the results of film thickness and optical value after stretching to change film-forming conditions. In addition, by continuously producing a long warp stretched film, a long warp stretched film having a desired length can be obtained.

As the thermoplastic resin included in the fabric film, an alicyclic olefin polymer resin (COP), a polycarbonate resin (PC), a cellulose ester resin, or the like can be used. Among them, the cellulose ester resin is easy to absorb moisture, and the orientation angle? Is likely to fluctuate due to the humidity variation accompanying long-time use. Therefore, the present embodiment The effect of the form becomes larger.

Further, the warp stretched film obtained by obliquely stretching the raw film can be applied to a liquid crystal display device which can be visually recognized by wearing polarized sunglasses. That is, a circularly polarizing plate is constituted by joining an obliquely stretched film to the viewer side of the polarizer of the viewer side polarizing plate rather than the liquid crystal layer. At this time, the both are bonded such that the slow axis of the obliquely drawn film and the transmission axis of the polarizer are 45 degrees. In this configuration, the linearly polarized light emitted from the liquid crystal layer and transmitted through the polarizer on the viewer side is converted into circularly polarized light by the obliquely drawn film (which functions as QWP). Therefore, in the case where the observer attaches the polarizing sunglasses and observes the display image of the liquid crystal display device, even if the angle between the transmission axis of the polarizer and the transmission axis of the polarizing sunglass is parallel to the transmission axis of the polarizing sunglass, It is possible to guide the display image to the eyes of the observer. Therefore, it is possible to suppress the display image from being hardly seen (depending on the direction of the transmission axis of the polarizing sunglass) depending on the viewing angle. In particular, by forming the warp stretched film using the raw film of this embodiment, unevenness of the orientation angle? In the film width direction can be suppressed. Therefore, even if the liquid crystal display device is used for a long time, Can be observed through polarized sunglasses.

Thus, when the obliquely stretched film is applied to the circularly polarizing plate of the liquid crystal display device corresponding to polarized sunglasses, it is preferable to form a hard coat layer for protecting the obverse-side stretched film on the obverse-side stretched film.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

<Cellulose ester-based resin>

The cellulose ester resin film used in the raw film of the present embodiment is preferably a cellulose ester resin film containing a cellulose acylate satisfying the following formulas (1) and (2) and further containing a compound represented by the following general formula (A) &Lt; / RTI &gt;

2.0 < / RTI &gt; &lt; RTI ID =

(2) 0? X <3.0

(In the formulas (1) and (2), Z1 represents the total acyl substitution degree of the cellulose acylate, and X represents the total of the propionyl substitution degree and the butyryl substitution degree of the cellulose acylate.)

Hereinafter, general formula (A) will be described in detail. In the general formula (A) L_One And L₂Each independently represents a single bond or a divalent linking group. L_One And L₂For example, the following structure. (In the following, R represents a hydrogen atom or a substituent.)

L ₁ and L ₂ is preferably -O-, -COO- or -OCO-.

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 (fluorine atom, chlorine atom, bromine atom and iodine atom), an alkyl group (methyl group, ethyl group, n- (Cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group and the like), alkenyl group (vinyl group, allyl group and the like), hydroxyl group (Such as a phenyl group, a p-tolyl group, or a naphthyl group), an alkenyl group (e.g., an isopropyl group, an n-butyl group, , A heterocyclic group (2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group and the like), cyano group, hydroxyl group, nitro group, carboxyl group, Butoxy group, 2-methoxyethoxy group, etc.), an aryloxy group (phenoxy group, 2-methylphenoxy group, 4-tert- Phenoxy group, 2- P-methoxyphenylcarbonyloxy group and the like), an amino group (an amino group (an amino group) such as an acyloxy group , An acylamino group (formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group and the like), an amino group such as a methylamino group, a dimethylamino group, an anilino group, Alkyl and arylsulfonylamino groups such as methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group and p-methylphenylsulfonylamino group, mercapto group, alkylthio group (Methylthio group, ethylthio group, n-hexadecylthio group and the like), arylthio group (phenylthio group, p-chlorophenylthio group and m-methoxyphenylthio group), sulfamoyl group Sulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N- (N'-phenylcarbamoyl) sulfamoyl group, etc.), a sulfo group, an acyl group (such as an acetyl group, a pivaloylbenzoyl group, etc.) ), Carbamoyl group (carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) ).

R ₁ and R ₂ are preferably a substituted or unsubstituted phenyl group or a substituted or unsubstituted cyclohexyl group, more preferably a phenyl group having a substituent or a cyclohexyl group having a substituent, more preferably a , A phenyl group having a substituent at the 4-position, 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, an acyloxy group, a cyano group, A hydrogen atom, a halogen atom, an alkyl group, a cyano group, or an alkoxy group.

Wa and Wb represent a hydrogen atom or a substituent,

(I) Wa and Wb may combine with each other to form a ring,

(II) at least one of Wa and Wb may have a cyclic structure, or

(III) At least one of Wa and Wb may be an alkenyl group or an alkynyl group.

Specific examples of the substituent represented by Wa and Wb include a halogen atom (fluorine atom, chlorine atom, bromine atom and iodine atom), an alkyl group (methyl group, ethyl group, n- Cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group etc.), cycloalkenyl group (2-ethylhexyl group, (Such as a phenyl group, a p-tolyl group, or a naphthyl group), a heterocyclic group (such as a cyclopenten-1-yl group or a 2-cyclohexene-1-yl group), an alkynyl group (an ethynyl group or a propargyl group) A cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group (a methoxy group, an ethoxy group, an isopropoxy group, an isopropoxy group, an isopropoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-methoxyphenoxy group, Tetradeca Amyloxy group, etc.), an acyloxy group (e.g., formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group and p-methoxyphenylcarbonyloxy group) An amino group, an amino group, a dimethylamino group, an anilino group, an N-methyl-anilino group and a diphenylamino group), an acylamino group (formylamino group, acetylamino group, pivaloylamino group, lauroylamino group and benzoylamino group) (Methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group, etc.), mercapto group, alkylthio group (E.g., methylthio, ethylthio, n-hexyldecylthio etc.), arylthio groups (phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group etc.), sulfamoyl groups Di-, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethyl sulf (E.g., an acetyl group, a pivaloylbenzoyl group and the like), a sulfo group, an acyl group (e.g., an acetyl group, a pivaloylbenzoyl group, etc.) (Carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group and the like) .

The substituent may also be substituted with such a group.

(I) When 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. It is particularly preferable that the formula (A) is a compound represented by the following formula (1) or (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 those of the substituent represented by Wa and Wb. Rx is preferably a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group.

In the general formula (1), X represents a nonmetal atom of Groups 14 to 16. X is preferably = O, = S, = NRc, = C (Rd) Re. Herein, Rc, Rd and Re represent substituents, and examples thereof are synonymous with the specific examples of the substituent represented by Wa and Wb. L ₁ , L ₂ , R ₁ , R ₂ , R ₃ , and n are the same as those in formula (A) L ₁ , L ₂ , R ₁ , R ₂ , R ₃ , n.

In the general formula (2), Q ₁ represents -O-, -S-, -NRy- (Ry represents a hydrogen atom or a substituent), -CRaRb- (wherein Ra and Rb represent a hydrogen atom or a substituent) CO-. Here, Ry, Ra and Rb represent a substituent, and examples thereof are the same as the specific examples of the substituent represented by Wa and Wb.

Y represents a substituent. Examples of the substituent represented by Y are the same as the specific examples of the substituent represented by Wa and Wb. Y is preferably an aryl group, a heterocyclic group, an alkenyl group or an alkynyl group.

Examples of the aryl group represented by Y include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group and a biphenyl group, and a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable.

Examples of the heterocyclic group include a heterocyclic group containing at least one hetero atom such as a nitrogen atom, an oxygen atom, and a sulfur atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group , A furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, and a thiazolyl group are preferable.

The aryl group or the heterocyclic group may have at least one substituent. 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, an alkylsulfonyl group having 1 to 6 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 6 carbon atoms, An alkylthio group having 1 to 6 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, an N-alkylamino group having 1 to 6 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 6 carbon atoms , An N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms, and the like.

L ₁ , L ₂ , R ₁ , R ₂ , R ₃ , and n are the same as those in formula (A) L ₁ , L ₂ , R ₁ , R ₂ , R ₃ , n.

(II) Specific examples of the case where at least one of Wa and Wb in the general formula (A) has a ring structure is preferably the following general formula (3).

In the general formula (3), Q ₃ represents ═N- or ═CRz- (Rz represents a hydrogen atom or a substituent), and Q ₄ represents a nonmetal atom of Groups 14 to 16. Z represents a group of nonmetal atoms forming a ring together with Q ₃ and Q ₄ .

The ring formed from Q ₃ , Q _4, and Z may be further branched to another ring. The ring formed from Q ₃ , Q ₄ and Z is preferably a nitrogen-containing 5-membered ring or a 6-membered ring condensed with a benzene ring.

L ₁ , L ₂ , R ₁ , R ₂ , R ₃ , and n are the same as those in formula (A) L ₁ , L ₂ , R ₁ , R ₂ , R ₃ , n.

(III) When at least one of Wa and Wb is an alkenyl group or an alkynyl group, they are preferably a vinyl group or an ethynyl group having a substituent.

Among the compounds represented by the general formulas (1), (2) and (3), the compound represented by the general formula (3) is particularly preferable.

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 superior in solubility to an organic solvent, Compatibility is good.

The compound represented by the general formula (A) may be contained in an appropriate amount to impart desired wavelength dispersibility and anti-smudge property. The amount of the compound to be added is preferably 1 to 15% by mass relative to the cellulose derivative , Particularly preferably from 2 to 10 mass%. Within this range, sufficient dispersibility of the cellulose derivative and dispersibility of the cellulose derivative can be imparted.

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, Journal of Chemical Crystallography (1997); 27 (9); 512-526), JP-A-2010-31223, JP-A-2008-107767, and the like.

(For cellulose acylate)

The cellulose acylate film according to the present embodiment contains cellulose acylate as a main component. For example, the cellulose acylate film according to the present embodiment contains cellulose acylate in an amount of preferably 60 to 100 mass% relative to the total mass (100 mass%) of the film. The degree of substitution of the cellulose acylate with respect to the total acyl group is preferably 2.0 or more and less than 3.0, and more preferably 2.2 to 2.7.

Examples of the cellulose acylate include cellulose and an ester of an aliphatic carboxylic acid and / or an aromatic carboxylic acid having about 2 to 22 carbon atoms, particularly an ester of cellulose and a lower fatty acid having 6 or less carbon atoms.

The acyl group bonded to the hydroxyl group of cellulose may be straight chain, branched or may form a ring. Further, a substituent may be substituted. When the number of carbon atoms is the same, the number of carbon atoms is preferably selected from an acyl group having 2 to 6 carbon atoms, and the total sum of propionyl substitution degree and butyryl substitution degree is from 0 to less than 3.0 to be. The cellulose acylate preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms.

Concretely, examples of the cellulose acylate include a cellulose acylate mixed with a cellulose having a propionate group, a butyrate group or a phthalyl group bonded in addition to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate or cellulose acetate phthalate Fatty acid esters can be used. The butyryl group forming the butyrate may be linear or branched.

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

The cellulose acylate preferably satisfies the following formulas (i) and (ii) simultaneously.

(I) 2.0? X + Y < 3.0

(Ii) 0? X <3.0

Y represents the substitution degree of the acetyl group, and X represents the substitution degree of the propionyl group or the butyryl group or mixture thereof.

Further, in order to obtain optical characteristics suitable for the purpose, resins having different degree of substitution may be mixed and used. The mixing ratio at that time is preferably 1:99 to 99: 1 (mass ratio).

Of the above, cellulose acetate propionate is particularly preferably used as the cellulose acylate. In the cellulose acetate propionate, it is preferable that 0? Y? 2.5 and 0.5? X? 3.0 (provided that 2.0? X + Y? 3.0) ? 2.0 (however, 2.0? X + Y? 3.0). The degree of substitution of the acyl group can be measured in accordance with ASTM-D817-96, which is one of the standards formulated and issued by the American Society for Testing and Materials (ASTM).

The number average molecular weight of the cellulose acylate is preferably in the range of from 60000 to 300000 because the mechanical strength of the obtained film is increased. More preferably, a cellulose acylate having a number average molecular weight of 70,000 to 200,000 is used.

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

Solvent: methylene chloride;

Column: Three shodex K806, K805, and K803G (manufactured by Showa Denko Kabushiki Kaisha) are connected and used;

Column temperature: 25 캜;

Sample concentration: 0.1 mass%;

Detector: RI Model 504 (manufactured by GL Science);

Pump: L6000 (manufactured by Hitachi Seisakusho Kabushiki Kaisha);

Flow rate: 1.0 ml / min

Calibration curve: standard polystyrene STK standard A calibration curve of 13 samples of polystyrene (manufactured by Toso Chemical Co., Ltd.) Mw = 1000000 to 500 is used. 13 samples are used at almost equal intervals.

The residual sulfuric acid content in the cellulose acylate is preferably in the range of 0.1 to 45 mass ppm in terms of sulfur element. They are thought to be contained in salt form. If the content of residual sulfuric acid exceeds 45 mass ppm, it tends to be easily broken at the time of heat stretching or slitting after thermal stretching. The residual sulfuric acid content is more preferably in the range of 1 to 30 mass ppm. The residual sulfuric acid content can be measured by the method specified in ASTM-D817-96.

The free acid content in the cellulose acylate is preferably 1 to 500 mass ppm. If it is in the above range, it is preferable that it is difficult to break as in the above. The content of the free acid is preferably in the range of 1 to 100 mass ppm, and the free acid is more difficult to break. And particularly preferably in the range of 1 to 70 mass ppm. The free acid content can be determined by the method specified in ASTM-D817-96.

The residual alkaline earth metal content, the residual sulfuric acid content, and the residual acid content can be set within the above-mentioned range by more thoroughly washing the synthesized cellulose acylate as compared with the solution used in the solution casting method.

The raw material cellulose of cellulose acylate is not particularly limited, but examples thereof include cotton linter, wood pulp and kenaf. Further, the cellulose acylates obtained therefrom may be mixed and used in any ratio.

The cellulose acylate can be produced by a known method. Specifically, it can be synthesized by referring to, for example, the method described in Japanese Patent Application Laid-Open No. 10-45804.

The cellulose acylate is also influenced by the trace metal components in the cellulose acylate. These trace metal components may be considered to be related to water used in the production process, but it is preferable that few components that can become insoluble nuclei. Particularly, metal ions such as iron, calcium, and magnesium may form an insoluble matter by forming a salt with a polymer decomposition product or the like, which may contain an organic acidic group. The calcium (Ca) component can easily form an acidic component such as a carboxylic acid or a sulfonic acid and also many ligands and a coordination compound (that is, a complex), and can produce a scum derived from a large amount of insoluble calcium ) May be formed.

Specifically, the content of the iron (Fe) component in the cellulose acylate is preferably 1 mass ppm or less. The content of the calcium (Ca) component in the cellulose acylate is preferably 60 mass ppm or less, and more preferably 0 to 30 mass ppm. The content of the magnesium (Mg) component in the cellulose acylate is preferably 0 to 70 mass ppm, more preferably 0 to 20 mass ppm, because the content of the magnesium (Mg) component is insufficient.

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 determined by decomposing the well-cleaned cellulose acylate into sulfuric acid in a micro digest wet cracking apparatus , And subjected to pretreatment with alkali melting, followed by analysis using an ICP-AES (inductively coupled plasma emission spectrometer).

&Lt; Alicyclic olefin polymer series resin >

Examples of the alicyclic olefin polymer-based resin used in the raw material film of this embodiment include a cyclic olefin random multi-component copolymer disclosed in Japanese Patent Application Laid-Open No. 05-310845, a polypropylene resin described in JP-A-05-97978 Hydrogenated polymers, thermoplastic dicyclopentadiene ring-opening polymers described in JP-A-11-124429, hydrogenated products thereof, and the like.

The alicyclic olefin polymer resin is a polymer having an alicyclic structure such as a saturated alicyclic hydrocarbon (cycloalkane) structure or an unsaturated alicyclic hydrocarbon (cycloalkene) structure. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually from 4 to 30, preferably from 5 to 20, and more preferably from 5 to 15. When the mechanical strength, heat resistance, And the moldability characteristics are highly balanced.

The proportion of the repeating unit containing an alicyclic structure in the alicyclic olefin polymer may be suitably selected, but is preferably 55% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more. When the proportion of the repeating unit having an alicyclic structure in the alicyclic polyolefin resin is within this range, the transparency and heat resistance of the optical material such as the retardation film obtained from the long oblong drawn film of the present embodiment are improved, which is preferable.

Examples of the olefin polymer resin having an alicyclic structure include a norbornene resin, a monocyclic cycloolefin resin, a cyclic conjugated diene resin, a vinyl alicyclic hydrocarbon resin, and a hydride thereof. Among them, the norbornene resin can be suitably used because of its good transparency and moldability.

As the norbornene resin, for example, a ring-opening polymer of a monomer having a norbornene structure or a ring-opening copolymer of a monomer having a norbornene structure and another monomer or a hydride thereof, an addition polymer of a monomer having a norbornene structure Or addition copolymers of monomers having a norbornene structure and other monomers, or hydrides thereof. Among them, the ring-opened (co) polymer hydride of a monomer having a norbornene structure can be suitably used particularly in view of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability and light weight.

As a method for molding a long film (textile film) using the norbornene resin as described above, a solution casting method or a melt extrusion method is preferable. As the melt extrusion method, there can be mentioned an inflation method using a die, etc. However, a method using a T-die is preferable because of its excellent productivity and thickness accuracy.

As the extrusion molding method using a T die, a method of maintaining a molten thermoplastic resin in a stable state when it is brought into close contact with a cooling drum, such as that described in Japanese Patent Application Laid-Open No. 2004-233604, It is possible to manufacture a long film having small variations in optical characteristics such as angle.

Specifically, 1) a method in which a sheet-shaped thermoplastic resin extruded from a die is brought into close contact with a cooling drum under a pressure of 50 kPa or less when the long film is produced by melt extrusion, 2) When a long film is produced by the melt extrusion method, the distance from the die opening portion to the cooling drum which is initially in close contact is covered with the surrounding member, and the distance from the surrounding member to the die opening portion or the cooling drum How to; 3) a method of warming the atmosphere temperature within 10 mm from the thermoplastic resin on the sheet extruded from the die opening to a specific temperature when the long film is produced by the melt extrusion method; 4) a method in which a sheet-shaped thermoplastic resin extruded from a die is brought into close contact with a cooling drum under a pressure of 50 kPa or less and is pulled; (5) A method of spraying a wind having a speed difference of not more than 0.2 m / s from the drawing speed of a cooling drum which is initially in close contact with a thermoplastic resin on a sheet extruded from a die opening portion by a melt extrusion method .

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 known method such as a coextrusion molding method, a shared softening molding method, a film lamination method, and a coating method. Of these, the co-extrusion molding method and the shared mold forming method are preferable.

<Polycarbonate-based resin>

As the polycarbonate resin used in the raw material film of the present embodiment, various resins can be used without particular limitation, and aromatic polycarbonate resins are preferable from the viewpoints of chemical properties and physical properties. Particularly, bisphenol A polycarbonate Nate resin is preferable. Among them, it is more preferable to use a bisphenol A derivative having a benzene ring, a cyclohexane ring, an aliphatic hydrocarbon group, or the like introduced into bisphenol A. Particularly preferred is a polycarbonate resin having a structure in which anisotropy in the unit molecule is reduced, obtained by using a derivative in which the functional group is introduced asymmetrically to the central carbon of bisphenol A. Examples of such polycarbonate resins include those obtained by replacing two methyl groups in the central carbon of bisphenol A with benzene rings and one hydrogen in each benzene ring of bisphenol A with methyl groups or phenyl groups, A polycarbonate resin obtained by using an asymmetrically substituted polycarbonate resin is particularly preferable.

Specifically, 4,4'-dihydroxydiphenylalkane or its halogen substituent is obtained by a phosgene method or an ester exchange method, and examples thereof include 4,4'-dihydroxydiphenyl methane, 4,4'-dihydroxydiphenyl methane, Dihydroxydiphenyl ethane, 4,4'-dihydroxydiphenyl butane, and the like. Further, for example, Japanese Patent Application Laid-Open Nos. 2006-215465, 2006-91836, 2005-121813, 2003-167121, and Japanese Patent Polycarbonate resins described in JP-A-2009-126128, JP-A-2012-31369, JP-A-2012-67300, and WO00 / 26705.

The polycarbonate resin may be used in combination with a transparent resin such as a polystyrene-based resin, a methyl methacrylate-based resin, and a cellulose acetate-based resin. Further, a resin layer containing a polycarbonate resin may be laminated on at least one surface of a resin film formed using a cellulose acetate resin.

The polycarbonate resin preferably has a glass transition point (Tg) of 110 ° C or more and a water absorption rate (value measured at 23 ° C under water for 24 hours) of 0.3% or less. 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 that can be used in the present embodiment can be formed by a known method, and among them, the solution casting method and the melt casting method are preferable.

<Additives>

The raw material film of this embodiment may contain an additive. Examples of the additives include plasticizers, ultraviolet absorbers, retardation-adjusting agents, antioxidants, deterioration inhibitors, release aids, surfactants, dyes, and fine particles. In the present embodiment, the additives other than the fine particles may be added at the time of producing the dope liquid or at the time of producing the fine particle dispersion.

(Plasticizer)

Examples of the plasticizer to be added to the fabric film include a phthalate ester, a fatty acid ester, a trimellitate ester, a phosphate ester, a polyester, a sugar ester, and an acrylic polymer. Among them, plasticizers of polyester series and sugar ester series polymers are preferably used from the viewpoint of moisture permeability.

The polyester-based plasticizer is superior to the phthalate ester-based plasticizer such as dioctyl phthalate in non-planarity and extrusion resistance. Depending on the application, these plasticizers may be selected or used in combination for a wide range of applications. As the acrylic polymer, homopolymers or copolymers of acrylic acid or methacrylic acid alkyl ester are preferable. Examples of the monomer of the acrylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-) , s-), hexyl acrylate (n- and i-), heptyl acrylate (n- and i-), octyl acrylate (n- and i-), nonyl acrylate (n- and i-) and myristyl acrylate -, i-), acrylic acid (2-ethylhexyl), acrylic acid (? -caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2- hydroxypropyl) (2-methoxyethyl), acrylic acid (2-ethoxyethyl), and the like, or those obtained by replacing the acrylic acid ester with a methacrylic acid ester have. The acrylic polymer is a homopolymer or a copolymer of the above-mentioned monomers. Preferably, the acryl-based polymer has a methyl acrylate monomer unit content of 30 mass% or more and a methacrylate methyl ester monomer unit content of 40 mass% or more. In particular, homopolymers of methyl acrylate or methyl methacrylate are preferred.

The polyester plasticizer is a reaction product of a mono- to tetravalent carboxylic acid with a mono- to hexavalent alcohol, and mainly one obtained by reacting a divalent carboxylic acid with a glycol is used. Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, and sebacic acid. The polyester plasticizer is preferably an aromatic terminal ester plasticizer. The aromatic terminal ester plasticizer is preferably an ester compound having a structure obtained by reacting phthalic acid, adipic acid, at least one benzene monocarboxylic acid, and at least one alkylene glycol having 2 to 12 carbon atoms. The structure of the final compound may be an adipic acid residue and a phthalic acid residue as long as it is a structure of the final compound, and may be reacted as an acid anhydride or esterified product of a dicarboxylic acid.

Examples of the benzene monocarboxylic acid component include benzoic acid, para-tert-butylbenzoic acid, orthotoluenic acid, meta-toluic acid, paratoluic acid, dimethylbenzoic acid, ethylbenzoic acid, normalpropylbenzoic acid, aminobenzoic acid, Most preferred is benzoic acid. These may be used alone or as a mixture of two or more kinds.

Examples of the alkylene glycol component having 2 to 12 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, Propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2- Propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1-n-butyl- Hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. Among these, 1,2-propylene glycol is particularly preferable. These glycols may be used alone or as a mixture of two or more thereof.

The aromatic terminal ester plasticizer may be any of oligoester and polyester, and the molecular weight is preferably in a range of from 100 to 10000, and more preferably in a range of from 350 to 3000. The acid value is not more than 1.5 mg KOH / g and the hydroxyl (hydroxyl value) is not more than 25 mg KOH / g, more preferably the acid value is not more than 0.5 mg KOH / g and the hydroxyl (hydroxyl value) is not more than 15 mg KOH / g.

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

The sugar ester compound is an ester other than a cellulose ester and is a compound obtained by esterifying all or a part of the OH group of a sugar such as the following monosaccharides, 2 sugars, 3 sugars or oligosaccharides. More specific examples are compounds represented by the general formula (4) And the like.

In the formulas, 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. R ₁ to R ₈ may be the same or different.

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

These plasticizers are preferably added in an amount of 0.5 to 30 parts by mass based on 100 parts by mass of the cellulose ester film.

(Retardation adjusting agent)

As a compound to be added for adjusting the retardation, an aromatic compound having two or more aromatic rings as described in European Patent No. 911,656A2 can be used.

Two or more kinds of aromatic compounds may be used in combination. It is particularly preferable that the aromatic ring of the aromatic compound further contains an aromatic heterocycle in addition to the aromatic hydrocarbon ring. The aromatic heterocycle is generally an unsaturated heterocycle. Among them, 1,3,5-triazine ring is particularly preferable.

(Polymer or oligomer)

The textile film of the present embodiment is a film of a vinyl compound having a cellulose ester and a substituent selected from a carboxyl group, a hydroxyl group, an amino group, an amide group and a sulfonic acid group, and having a weight average molecular weight of 500 to 200,000 Or an oligomer. The mass ratio of the content of the cellulose ester to the polymer or oligomer is preferably in the range of 95: 5 to 50:50.

(Made by Matt)

In the present embodiment, fine particles can be contained in the raw material film as a matting agent, whereby it is easy to carry and wind the raw material film and the long warp stretched film produced using the raw material film.

It is preferable that the particle size of the mat agent is primary particles or secondary particles of 10 nm to 0.1 占 퐉. A substantially spherical mat material having an aspect ratio of primary particles of 1.1 or less is preferably used.

As the fine particles, those containing silicon are preferable, and silicon dioxide is particularly preferable. Examples of the fine particles of silicon dioxide which are preferable in the present embodiment include fine particles of silicon dioxide such as Aerosil R972, R972V, R974, R812,200, 200V, 300, R202, OX50, TT600 (available from Nippon Aerosil Co., Aerosil 200V, R972, R972V, R974, R202 and R812 can be preferably used. Examples of the fine particles of the polymer include a silicone resin, a fluororesin, and an acrylic resin. Silicone resin is preferable, and it is particularly preferable to have a three-dimensional network structure. Examples of such resins include Tospearl 103, Copper 105, Copper 108, Copper 120, Copper 145, Copper 3120 and Copper 240 (manufactured by Toshiba Silicone Co., Ltd.).

The fine particles of silicon dioxide preferably have a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / L or more. More preferably, the primary particles have an average diameter of 5 to 16 nm, more preferably 5 to 12 nm. The smaller the average diameter of the primary particles is, the lower the haze is. The apparent specific gravity is preferably 90 to 200 g / L or more, more preferably 100 to 200 g / L or more. As the apparent specific gravity is larger, it becomes possible to produce a dispersion liquid of a high concentration of fine particles, and haze and agglomerates are not generated, which is preferable.

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 fabric film.

(Other additives)

Other heat stabilizers such as kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide and alumina, and salts of alkaline earth metals such as calcium and magnesium may be added. Further, a surfactant, a peeling accelerator, an antistatic agent, a flame retardant, a lubricant, an emulsion or the like may be added.

(Tension softening point)

The fabric film of this embodiment is required to be able to withstand use under a higher temperature environment. For this reason, the tensile softening point of the fabric film is preferably from 105 캜 to 145 캜 because it exhibits sufficient heat resistance, and more preferably from 110 캜 to 130 캜.

As a specific measuring method of the tensile softening point, for example, a sample film is cut to 120 mm (length) x 10 mm (width) using a tensilon tester (RTC-1225A manufactured by ORIENTEC Co.) The temperature is maintained at a heating rate of 占 폚 / min, the temperature at the point of time when the temperature becomes 9N is measured three times, and the average value is obtained.

(Dimensional change rate)

When the film obtained by obliquely stretching the fabric film of the present embodiment is used for an organic EL image display apparatus, problems such as variations in thickness, a change in retardation value, and a reduction in contrast or color irregularity occur due to dimensional changes due to moisture absorption , The dimensional change rate (%) of the obliquely drawn film is preferably less than 0.5%, more preferably less than 0.3%.

(fault)

It is preferable that the raw material film of the present embodiment has few defects in the film. The drawback here is that, in the drying step of the solution film forming process, the solvent (foreign matter defect) in the film due to the sudden evaporation of the film (foaming defect) or the foreign substance in the film forming solution and the foreign substance It says.

Concretely, it is preferable that defects with a diameter of 5 m or more in the film surface are 1/10 cm square or less. More preferably at most 0.5 / 10 cm square, further preferably at most 0.1 / 10 cm square.

The diameter of the defect refers to the diameter when the defect has a circular shape, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter is defined as the diameter of the circumscribed circle.

The range of the defect is the size of the shadow when the defect is observed as the transmitted light of the differential interference microscope when the defect is bubble or foreign matter. When the defect is a change in surface shape such as a transfer of a roll scratch or a scratch, the size is confirmed by observing the defect as reflected light of a differential interference microscope.

In the case of observing with reflected light, if the size of the defect is unclear, aluminum or platinum is deposited on the surface and observed. In order to obtain a film having excellent durability expressed by such defect frequency with high productivity, it is necessary to perform high-precision filtration of the polymer solution just before the preparation, increase the degree of cleanliness around the polymer smoke, , It is effective to make the drying effective by suppressing foaming.

If the number of defects is more than 1/10 cm square, for example, if a tensile force is applied to the film at the time of processing in a subsequent process, etc., the film may be broken at the beginning of the defect and the productivity may be lowered. When the diameter of the defect is 5 mu m or more, it can be confirmed visually by observing the polarizing plate or the like, and a bright spot may be generated when used as an optical member.

(Total light transmittance)

The raw film of the present embodiment preferably has a total light transmittance of 90% or more, more preferably 93% or more. The practical upper limit of the total light transmittance is about 99%. In order to achieve the excellent transparency expressed by the total light transmittance, it is necessary to prevent introduction of an additive or a copolymerizable component that absorbs visible light, remove foreign matter in the polymer by high-precision filtration, and reduce light diffusion or absorption inside the film . Further, it is possible to reduce the surface roughness of the film contacting portion (cooling roll, calender roll, drum, belt, coating liquid in the solution film forming process, conveying roll, etc.) at the time of film formation to reduce the surface roughness of the film surface, It is effective to reduce reflection.

&Lt; Method of forming a fabric film &

The raw film of the present embodiment containing the above-mentioned resin can be formed by any one of the solution casting film forming method and the melt casting film forming method described below. Here, the case where the fabric film includes a cellulose ester-based resin is explained, but the case where other resin is included is also the same.

When the fabric film is produced by the solution casting method, the dope, which is the raw material solution of the raw film of the cellulose ester resin, is softened on a support comprising a rotating metal endless belt by a flexible die. The dope film, that is, the web formed on the support by the softening is peeled off by the peeling roll when the support is about one week. The peeled web (film) is continuously introduced into a stretching apparatus including a tenter.

In the extrusion method using a T-die, the polymer is melted at a melting temperature and extruded from a T-die into a film-type (sheet-like) on a cooling drum, cooled and solidified, The film is peeled off. The peeled film is subsequently introduced into a stretching apparatus including a tenter.

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

[Solution flexible film-forming method]

In the method for producing a raw fabric film by the solution softening method, the solid concentration of the dope as the cellulose ester solution is usually about 10 to 40 mass%, and the dope viscosity in the softening step is in the range of 1 to 200 poise &Lt; / RTI &gt;

Here, first, the cellulose ester is dissolved by a means such as a stirring dissolving method, a heating dissolving method, an ultrasonic melting method and the like in a melting pot. Usually, the cellulose ester is melted in a range where the boiling point of the solvent is higher than the boiling point at normal pressure, , And dissolving with stirring is more preferable in order to prevent the occurrence of a massive undissolved product called a gel or agglomerate. Further, the cooling dissolution method disclosed in Japanese Patent Application Laid-Open No. 9-95538 or the method disclosed in Japanese Patent Application Laid-Open No. 11-21379 may be used.

A method in which the cellulose ester is mixed with a poor solvent, wetted or swelled, and then mixed with a two-component agent and dissolved is also preferably used. At this time, an apparatus for mixing cellulose ester with a poor solvent to wet or swell the apparatus and a system for dissolving the cellulose ester by mixing with the two agents may be separately provided.

The kind of the pressure vessel used for dissolving the cellulose ester is not particularly limited, but it is only required to be able to withstand a predetermined pressure and to be heated and stirred under pressure. Instrumentation such as a gauge, a pressure gauge, and a thermometer is appropriately placed in the pressure vessel. Pressurization may be performed by a method of pressurizing an inert gas such as nitrogen gas or by raising the vapor pressure of the solvent by heating. Heating is preferably performed from the outside, and for example, a jacket type is preferable because temperature control is easy.

The heating temperature in the case of adding a solvent is not less than the boiling point of the solvent to be used, and in the case of two or more mixed solvents, the temperature is raised to a temperature not lower than the boiling point of the solvent having a lower boiling point, . If the heating temperature is too high, the required pressure is increased and the productivity is deteriorated. The preferable range of the heating temperature is from 20 to 120 캜, more preferably from 30 to 100 캜, still more preferably from 40 to 80 캜. Further, the pressure is adjusted so that the solvent does not boil at the set temperature.

In addition to the cellulose ester and the solvent, additives such as necessary plasticizers and ultraviolet absorbers may be previously mixed with the solvent, dissolved or dispersed, and then added to the solvent before the cellulose ester dissolution, or may be added to the dope after the dissolution of the cellulose ester.

After dissolving the cellulose ester, the cellulose ester is taken out of the vessel while being cooled, or extracted from the vessel by a pump or the like, cooled with a heat exchanger or the like, and provided for the dope film formation of the obtained cellulose ester.

When the mixture of the cellulose ester raw material and the solvent is dissolved in the dissolution apparatus having the stirrer, it is preferable that the main stream of the stirring blades is dissolved at least 0.5 m / sec or more and for 30 minutes or more with stirring.

The foreign matter contained in the cellulose ester dope (particularly foreign matter mistakenly recognized as an image in the liquid crystal display device) must be removed by filtration. The quality of the optical film may be determined by this filtration.

It is preferable that the filtration material used for filtration has a small absolute filtration accuracy. However, if the absolute filtration precision is too small, clogging of the filter material tends to occur, and the filtration material must be frequently exchanged. Therefore, the filter material used for the cellulose ester dope preferably has an absolute filtration accuracy of 0.008 mm or less, more preferably 0.001 to 0.008 mm, and even more preferably 0.003 to 0.006 mm.

The material of the filter medium is not particularly limited and a normal filter medium can be used. However, a filter material made of plastic fibers such as polypropylene or Teflon (registered trademark) or a metal filter material made of stainless steel fibers and the like is preferable .

The filtration of the cellulose ester dope can be carried out by a usual method, but a method of filtration while heating under pressure at a temperature in the range of the boiling point of the solvent at normal pressure and at a temperature not boiling the solvent, ) Is small, which is preferable.

The preferable range of the filtration temperature is 45 to 120 캜, more preferably 45 to 70 캜, still more preferably 45 to 55 캜.

The filtration pressure is preferably 3500 kPa or less, more preferably 3000 kPa or less, and still more preferably 2500 kPa or less. The filtration pressure can be controlled by appropriately selecting the filtration flow rate and the filtration area.

In order to produce a cellulose ester based resin film, firstly, the cellulose ester is dissolved in a mixed solvent of a good solvent and a poor solvent, and the above plasticizer or ultraviolet absorber is added thereto to prepare a cellulose ester solution (dope).

The dope can be flexible on the support at temperatures in the range of from 0 ° C to below the boiling point of the solvent and further flexible on the support in the temperature range from 5 ° C to the solvent boiling point of -5 ° C, Lt; RTI ID = 0.0 &gt; C, &lt; / RTI &gt; At this time, it is necessary to control the surrounding atmosphere humidity to be equal to or higher than the dew point.

When the dope adjusted so as to have a viscosity of 1 to 200 poises is softened to have a substantially uniform film thickness on the support from the flexible die and the amount of residual solvent in the flexible film is greater than or equal to 200% (Web) is dried with the drying air so that the temperature of the flexible film is in the range of the solvent boiling point + 20 ° C or less until the residual solvent amount is less than or equal to 200%.

Here, the residual solvent amount can be expressed by the following formula.

Amount of residual solvent (mass%) = {(M-N) / N} 100

In the formula, M is the weight of the web at any point in time, and N is the weight of the weight M when dried at 110 ° C for 3 hours.

On the support, the amount of the residual solvent in the web is preferably dried to 150 mass% or less, more preferably 50 to 120 mass%, in order to dry and solidify the web until the film becomes peelable film strength from the support.

The web temperature at which the web is peeled from the support is preferably 0 to 30 占 폚. Further, since the temperature of the web is rapidly lowered by the evaporation of the solvent from the side of the support adhering surface immediately after peeling from the support, and volatile components such as steam and solvent vapor in the atmosphere are easily condensed, More preferably 5 to 30 &lt; 0 &gt; C.

In the drying process of the web (or film), a method of drying while conveying the web by a roll suspension system, a pin tenter system or a clip tenter system is generally employed.

The web after peeling is introduced into, for example, a primary drying apparatus. In the primary drying apparatus, the web is conveyed serially by a plurality of conveying rolls staggered from the side, while the web is blown from the ceiling of the drying apparatus and discharged from the bottom portion of the drying apparatus And dried.

Subsequently, the obtained film (sheet) is stretched in the uniaxial direction. The molecules are oriented by stretching. The stretching method is not particularly limited, but a well-known pin tenter or clip-type tenter can be preferably used. The stretching direction may be a longitudinal direction, a width direction, or an arbitrary direction (oblique direction), but it is preferable that the elongation of the fabric film is easy to adjust by making the stretching direction to be the width direction.

In particular, in the drying step after peeling from the support, the web tends to shrink in the width direction by evaporation of the solvent. The shrinkage increases with drying at high temperature. It is preferable to dry the film while suppressing the shrinkage as much as possible in order to improve the flatness of the finished film. In this respect, for example, a method (tenter method) in which the pre-drying step or a part of the steps disclosed in Japanese Patent Application Laid-Open No. 62-46625 is carried out while keeping both ends of the width of the web at a width desirable.

As the stretching condition of the raw material film, the temperature and the magnification can be selected so that the desired elongation at break characteristic can be obtained. Generally, the stretching magnification is 1.1 to 2.0 times, preferably 1.2 to 1.5 times, and the stretching temperature is usually from -40 占 폚 to Tg + 50 占 폚 of the glass transition temperature (Tg) of the resin constituting the sheet, Lt; RTI ID = 0.0 &gt; 40 C &lt; / RTI &gt; If the stretch ratio is too small, desired stretch elongation characteristics may not be obtained. On the other hand, if the stretch ratio is too large, breakage may occur. If the stretching temperature is too low, it breaks. If the stretching temperature is too high, the desired elongation at break characteristic may not be obtained.

In the case of modifying the breaking elongation property of the thermoplastic resin film produced by the above method to a desired characteristic suited to the purpose, the film may be stretched or shrunk in the longitudinal direction or the width direction. In order to contract in the longitudinal direction, for example, there is a method in which the film is shrunk by causing the width stretching to temporarily clip out and loosening in the longitudinal direction, or by gradually narrowing the interval between adjacent clips of the transverse stretching device. The latter method can be performed by a method in which a common simultaneous biaxial stretching device is used to smoothly and gradually narrow the distance between adjacent longitudinally-extending clips by driving the clip portion with, for example, a pantograph method or a linear drive method.

The holding and stretching in the tenter may be carried out anywhere from 50 to 150% by mass of the film residual solvent immediately after peeling to 0% by mass of the substantial residual solvent immediately before the peeling, but the residual solvent content is preferably in the range of 5 to 10% .

It is also often common to divide the tenter into several temperature zones in the running direction of the base. The temperature at which the desired physical properties and planarity are obtained is selected as the temperature at the time of stretching, but the temperature of the drying zone before and after the tenter may also be selected to be different from the temperature at the time of stretching for various reasons. For example, when the atmospheric temperature of the drying zone before the tenter is different from the temperature in the tenter, it is generally preferable to set the temperature of the zone near the inlet of the tenter to a temperature intermediate the temperature of the drying zone before the tenter and the temperature of the center of the tenter It is being done. Similarly, when the temperature in the tenter aftertenter is different, the temperature of the zone close to the tenter outlet is set to the intermediate temperature between the temperature in the tenter and the temperature in the tenter. The temperature of the drying zone before and after the tenter is generally 30 to 120 DEG C, preferably 50 to 100 DEG C, the temperature of the drawing portion in the tenter is 50 to 180 DEG C, preferably 80 to 170 DEG C, The negative temperature is appropriately selected at their intermediate temperature.

The pattern of the stretching, that is, the trajectory of the gripping clip, is selected from optical properties and planarity of the film as in the case of temperature, and is various. It has a certain width after the start of grinding and is then stretched, It is well used. In the vicinity of the end of the clip grip near the tenter outlet, width reduction is generally performed to suppress the base vibration by opening the grip.

The pattern of stretching is also related to the stretching speed, which is generally in the range of 10 to 1000 (% / min), preferably 100 to 500 (% / min). This stretching speed is not constant when the clip trajectory is a curve, but gradually changes in the running direction of the base.

Further, the web (film) after drying by the tenter system is continuously introduced into the secondary drying apparatus. In the secondary drying apparatus, the web is conveyed serially by a plurality of conveying rolls staggered from the side, while the web is blown from the ceiling of the secondary drying apparatus, and further from the bottom portion of the secondary drying apparatus Dried by warm air to be discharged, and wound around a winding machine as a raw film of a cellulose ester resin.

As means for drying the web, hot air, infrared rays, heating rolls, microwaves, etc. are generally used without particular limitation. In terms of convenience, it is preferable to dry with hot air. The drying temperature is preferably 40 to 150 占 폚, and more preferably 80 to 130 占 폚 because planarity and dimensional stability are improved.

Thus, in the web drying step, the web peeled from the support is further dried, and finally the residual solvent amount is adjusted to 3 mass% or less, preferably 1 mass% or less, more preferably 0.5 mass% or less Is preferable in order to obtain a film having good dimensional stability.

The process from the softening to the post-drying may be performed in an air atmosphere, or in an inert gas atmosphere such as nitrogen gas. In this case, it goes without saying that the drying atmosphere is carried out in consideration of the explosive limit concentration of the solvent.

In addition, in the case where the embossing device is used for embossing on both side edge portions of the cellulose ester resin raw material film at the front end of the cellulose ester resin finished film which has been subjected to the conveying and drying step, . As the embossing apparatus, for example, an apparatus described in Japanese Patent Application Laid-Open No. 63-74850 can be used.

The winding machine relating to the production of the cellulose ester resin-based raw material film can be wound by a winding method such as a normal tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress .

Though the film thickness of the raw fabric film after winding is different depending on the purpose of use, the film thickness range is 20 to 200 占 퐉, and in recent thin tendency, it is preferably in the range of 30 to 120 占 퐉, more preferably in the range of 40 to 100 占 퐉 desirable.

When the raw fabric film of the present embodiment is produced by the melt softening film forming method, the ultraviolet absorber which can be used may be substantially the same as that used in the method for producing a raw film by the solution casting method.

The blending amount of these ultraviolet absorbers is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass with respect to the thermoplastic resin. If the amount 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 preferably has high thermal stability.

It is preferable to add fine particles to the fabric film in order to impart slipperiness of the film. As the fine particles to be used, any of inorganic compounds or organic compounds may be used if they have heat resistance at the time of melting. Examples of the inorganic compounds include silicon compounds, silicon dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, Clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate are preferable, and an inorganic compound containing zirconium or zirconium oxide is more preferable. Among them, silicon dioxide is particularly preferably used in that the haze can be suppressed small. Even when the fabric film is produced by the melt soft-film-forming method, as the matting agent to be used, substantially the same materials as those used in the manufacturing method of the raw film by the solution casting method can be used.

Examples of the melt soft-film-forming method include a melt-extrusion method such as a method using a T-die or an inflation method, a calendering method, a hot pressing method, and an injection molding method. Among them, a method using a T-die, which is small in thickness unevenness, easy to be processed to a thickness of about 50 to 500 탆, and capable of reducing unevenness in film thickness and unevenness of retardation, is preferable. The extrusion method using a T die is a method in which a polymer is melted at a melting temperature and is extruded from a T die onto a cooling drum in a film form (sheet form), cooled and solidified, and peeled off from the cooling drum. Can be preferably used.

The melt extrusion can be carried out under the same conditions as those used for other thermoplastic resins such as polyester. For example, the cellulose ester which has been dried under a hot air, a vacuum or a reduced pressure is melted at an extrusion temperature of about 200 to 300 DEG C by using a uniaxial or biaxial extruder, filtered with a filter such as a leaf disk type filter, T-die to film (sheet-like) and solidify on a cooling drum. When introduced into the extruder from the feed hopper, it is preferable to prevent the oxidative decomposition or the like under an atmosphere of reduced pressure or inert gas.

It is preferable that the extrusion flow rate is performed by introducing a gear pump and stabilizing the flow rate. In addition, a stainless steel fiber sintered filter is preferably used as a filter used for removing foreign matters. The stainless steel fiber sintering filter is formed by integrally forming a stainless steel fiber body in a state of being entangled with each other and then compressing and sintering the contact portions so that the filtration accuracy can be adjusted by changing the density depending on the thickness of the fibers and the amount of compression. It is preferable that the filtration precision is a multilayer body obtained by repeating a plurality of times continuously by a coarse and a mill. In addition, it is preferable to adopt a configuration in which the filtration accuracy is gradually increased, or the filtration accuracy is adjusted and the repetition of the filtration is repeated, so that the filtration life of the filter is prolonged and the replenishment precision of foreign matters and gels can be improved.

When scratches or foreign matter adheres to the die, a stripe-like defect may occur. Such a defect is called a die line. In order to reduce defects on the surface of a die line or the like, it is preferable that the pipe from the extruder to the die has a structure in which the retention portion of the resin is minimized. In addition, it is preferable to use the die without any scratches or the like on the inside or the lip of the die. The volatile component is precipitated from the resin around the die, which may cause die lines. Therefore, it is preferable to suck the atmosphere containing the volatile component. In addition, there is a case where precipitation may occur also in an apparatus such as an electrostatic attraction, and it is preferable to apply alternating current or prevent precipitation by other heating means.

Additives such as plasticizers may be mixed with the resin in advance, or they may be put in the middle of the extruder. In order to uniformly add it, it is preferable to use a mixing device such as a static mixer.

The temperature of the cooling drum is preferably not higher than the glass transition temperature of the thermoplastic resin. In order to adhere the resin to the cooling drum, it is preferable to use a method of tightly adhering to the cooling drum by static electricity, a method of closely adhering by wind pressure, a method of tightly adhering to the entire width or end portion,

The raw film of the thermoplastic resin molded by the melt soft film forming method is different from the raw film formed by the solution softening method and has a feature that the retardation in the thickness direction (Rt) is small. In some cases. In order to obtain the desired optical properties, in some cases, stretching in the film advancing direction and stretching in the film width direction may be performed simultaneously or sequentially. In some cases, the film may be stretched only in the film width direction. The molecules are oriented by this stretching operation, and the film is adjusted to a necessary retardation value.

<Specification of fabric film>

The thickness of the raw film in this embodiment is preferably 1 to 400 占 퐉, preferably 20 to 200 占 퐉, more preferably 30 to 120 占 퐉, particularly preferably 40 to 100 占 퐉. Further, in this embodiment, the thickness unevenness sigma m in the flow direction (transport direction) of the raw film fed to the stretching zone described later can be obtained by maintaining the pulling tension of the film at the entrance of the oblique stretching tenter, It is required to be less than 0.30 mu m, preferably less than 0.25 mu m, and more preferably less than 0.20 mu m from the viewpoint of stabilizing the optical characteristics such as the optical characteristics. When the thickness unevenness? M in the flow direction of the raw material film is 0.30 占 퐉 or more, variations in optical characteristics such as retardation and orientation angle of the long oblong drawn film are remarkably deteriorated.

In addition, in order to suppress the occurrence of uneven orientation angles in the width direction due to the thickness unevenness in the width direction by the oblique stretching, it is preferable that the thickness unevenness in the width direction of the raw material film is small. For example, in the width direction of the raw fabric film, the difference in thickness between the end on the thick side and the end on the thin side is less than 2.0%, preferably less than 1.0%, more preferably less than 0.5% It is preferable to include a range of about &lt; RTI ID = 0.0 &gt;

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

The modulus of elasticity at the stretching temperature at the time of warp stretching of the fabric film is expressed by the Young's modulus and is from 0.01 MPa to 5000 MPa, more preferably from 0.1 MPa to 500 MPa. When the elastic modulus is too low, the shrinkage rate after stretching and drawing is low, and wrinkles are hardly lost. If the elastic modulus is too high, the tensile force at the time of 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 on the tenter in the subsequent process is increased.

As the raw material film, there may be used a non-oriented film or a film having a predetermined orientation. Further, if necessary, the distribution in the width direction of the orientation of the raw material film may be arcuate, so-called bowing. The orientation of the raw film can be adjusted so that the orientation of the film at the position where the drawing of the subsequent process is completed can be desired.

&Lt; Method of manufacturing oblique stretched film &

Next, a description will be given of a method and a device for producing a warp stretched film, in which the long film is stretched in the oblique direction with respect to the width direction to produce a long obliquely stretched film.

(Overview of the device)

1 is a plan view schematically showing a schematic configuration of an apparatus 1 for producing an obliquely-drawn film. The manufacturing apparatus 1 comprises a film feed portion 2, a transport direction changing portion 3, a guide roll 4, a stretching portion 5, and a guide roll 6, a transport direction changing section 7, and a film winding section 8. [0034] Further, a film cutting device may be provided between the transport direction changing portion 7 and the film winding portion 8, the film after the warp stretching may be cut to a desired length, and the film may be wound by the film winding portion 8. Details of the stretching portion 5 will be described later.

The film feeding portion 2 uncovers the long film and feeds it to the stretching portion 5. The film feeder 2 may be formed separately from the film forming apparatus of the long film, or may be integrally formed. In the case of the former, the long film is unwound from the film feeding portion 2 by winding the long film on the winding core once after winding the film to form a winding body (long film fabric). On the other hand, in the latter case, after film formation of the long film, the film feeding portion 2 uncovers the long film to the stretching portion 5 without winding.

The transport direction changing section 3 changes the transport direction of the long film to be unwound from the film feed section 2 in the direction toward the entrance of the stretching section 5 as the oblique stretching tent. The transport direction changing portion 3 includes a turn bar for changing the transport direction by folding while transporting the film, for example, and a rotary table for rotating the turn bar in a plane parallel to the film.

By changing the conveying direction of the long film in the conveying direction changing section 3 as described above, the width of the entire manufacturing apparatus 1 can be made narrower, and besides, the conveying position and angle of the film can be finely controlled It becomes possible to obtain a warp stretched film having a small variation in film thickness and optical value. When the film feeding portion 2 and the conveying direction changing portion 3 are movable (slidable and pivotable), the stretching portion 5 is provided with the right and left clips It is possible to effectively prevent the sticking defects of the film on the film.

The film feed portion 2 may be slidable and pivotable so as to allow a long film to pass through the entrance of the stretching portion 5 at a predetermined angle. In this case, it is also possible to adopt a configuration in which the installation of the transport direction changing section 3 is omitted.

At least one guide roll 4 is provided on the upstream side of the stretching portion 5 in order to stabilize the trajectory of the long film during traveling. Further, the guide roll 4 may be constituted by a pair of upper and lower pairs of rolls sandwiching the film, or a pair of rolls. The guide roll 4 closest to the entrance of the stretching portion 5 is a driven roll for guiding the running of the film and is rotatably supported by a bearing portion (not shown). As the material of the guide roll 4, known rollers can be used. Further, in order to prevent scratches on the film, it is preferable to reduce the weight of the guide roll 4 by applying a ceramic coating to the surface of the guide roll 4, or chrome plating the light metal such as aluminum.

It is preferable that one of the rolls on the upstream side of the guide roll 4 closest to the entrance of the stretching section 5 is nipped by pressing the rubber roll. By using such a nip roll, fluctuation of the unwinding tension in the flow direction of the film can be suppressed.

A pair of bearing portions at both ends (right and left) of the guide roll 4 closest to the entrance of the stretching portion 5 are provided with a film tension detecting device for detecting a tension generated in the film in the roll, A tension detecting device, and a second tension detecting device are provided, respectively. As the film tension detecting device, for example, a load cell can be used. As the load cell, a known type of tensile or compression type can be used. The load cell is a device that converts a load acting on a point of contact to an electric signal by a strain gage provided on the deformable body and detects the load.

The load cell is provided at the left and right bearing portions of the guide roll 4 closest to the entrance of the stretching section 5 so that the force of the film being driven during the running on the roll, And detects the tension in the left and right independently. Further, a strain gauge may be provided directly on a support constituting the bearing portion of the roll, and the load, that is, the film tension may be detected based on the deformation occurring in the support. The relationship between the generated deformation and the film tension is measured in advance and assumed to be known.

When the position and transport direction of the film supplied from the film feed portion 2 or the transport direction changing portion 3 to the stretching portion 5 are shifted from the position toward the entrance of the stretching portion 5 and the transport direction, A difference occurs in the tension in the vicinity of both side edge portions of the film in the guide roll 4 closest to the entrance of the stretching portion 5 depending on the amount of misalignment. Therefore, by detecting the tension difference by installing the film tension detecting device as described above, it is possible to determine the degree of the deviation. That is, when the transporting position and the transporting direction of the film are appropriate (the position and direction toward the inlet of the stretching section 5), the load acting on the guide roll 4 becomes approximately equal at both ends in the axial direction, Otherwise, difference in film tension occurs between right and left.

Therefore, in order to equalize the difference in film tension between the left and right sides of the guide roll 4 closest to the entrance of the stretching section 5, for example, the position and direction of the film (stretching section 5 ) Is appropriately adjusted, the holding of the film by the wave-like earth at the entrance of the stretching portion 5 is stabilized, and occurrence of troubles such as deviation from the wave-like earth can be reduced. In addition, it is possible to stabilize the physical properties of the film in the width direction after the warp stretching by the stretching portion (5).

At least one guide roll 6 is provided on the downstream side of the stretching section 5 in order to stabilize the trajectory at the time of running of the obliquely stretched film in the stretching section 5.

The transport direction changing section 7 changes the film transport direction after stretching, which is transported from the stretching section 5, to the film winding section 8. [

Here, the film advancing direction at the entrance of the stretching section 5 and the film advancing direction at the exit of the elongating section 5 are set so as to correspond to the fine adjustment of the orientation angle (the direction of the in-plane slow axis in the film) It is necessary to adjust the angle. In order to adjust the angle, the direction in which the film is formed is changed by the transport direction changing section 3 to guide the film to the entrance of the stretching section 5, and / or the film from the exit of the stretching section 5 It is necessary to change the traveling direction of the film by the carrying direction changing portion 7 to return the film to the direction of the film winding portion 8.

In addition, it is preferable to continuously perform film formation and warp stretching in terms of productivity and yield. When the film forming process, the warp stretching process, and the winding process are continuously performed, the film advancing direction is changed by the carrying direction changing portion 3 and / or the carrying direction changing portion 7, As shown in Fig. 1, the direction in which the film is unwound from the film feeding portion 2 and the film advancing direction immediately before being wound in the film winding portion 8 Winding direction), it is possible to reduce the width of the entire device with respect to the film advancing direction.

It is not necessary that the film advancing direction in the film forming process and the winding process necessarily coincides with each other, but the direction of the film conveying direction changing section 3 and / or the film winding direction changing section 3 is set such that the film feeding section 2 and the film winding section 8 do not interfere with each other. Or the carrying direction changing portion 7 to change the traveling direction of the film.

The above-described transport direction changing unit 3 · 7 can be realized by a known method such as using an air flow roll or an air turn bar.

The film take-up portion 8 is for winding a film conveyed from the stretching portion 5 through the conveying direction changing portion 7 and is constituted by, for example, a winder device, an algebraic device, a drive device or the like. It is preferable that the film take-up unit 8 is a structure that can slide in the lateral direction to adjust the winding position of the film.

The film take-up portion 8 is capable of finely controlling the take-in position and angle of the film so that the film can be pulled at a predetermined angle with respect to the exit of the stretching portion 5. [ This makes it possible to obtain a long oblong stretched film having a small variation in film thickness and optical value. In addition, the occurrence of wrinkles of the film can be effectively prevented, and the winding-up property of the film is improved, so that the film can be wound up a long time.

The film winding portion 8 constitutes a pulling portion for pulling the film being stretched by the stretching portion 5 and pulling it with a predetermined tension. Between the stretching portion 5 and the film take-up portion 8, a take-up roll for pulling the film with a constant tension may be provided. The guide roll 6 described above may have a function as the take-up roll.

In the present embodiment, the film pulling tension T (N / m) after stretching is preferably adjusted to be within the range of 100 N / m <T <300 N / m, preferably 150 N / m <T <250 N / m. If the pulling tension is 100 N / m or less, the film tends to relax or wrinkle, and the profile of retardation and orientation angle in the film width direction is deteriorated. On the other hand, when the pulling tension is 300 N / m or more, the variation of the orientation angle in the film width direction becomes worse, and the width yield (efficiency in the widthwise direction) deteriorates.

In the present embodiment, it is preferable to control the fluctuation of the take-up tension T at an accuracy of less than ± 5%, preferably less than ± 3%. If the fluctuation of the take-up tension T is ± 5% or more, fluctuation of the optical characteristics in the width direction and the flow direction (transport direction) becomes large. As a method of controlling the fluctuation of the take-up tension T within the above range, the load applied to the first roll (guide roll 6) on the exit side of the stretching portion 5, that is, the tensile force of the film is measured, A method of controlling the rotation speed of the take-up roll of the take-up roll or the film take-up unit 8 by a general PID control method may be mentioned. As a method for measuring the load, there is a method in which a load cell is provided on the bearing portion of the guide roll 6 and the load applied to the guide roll 6, that is, the tensile force of the film is measured. As the load cell, a known type of tensile type or compression type can be used.

After stretching the film, the gripping of the stretching portion 5 is released, the film is discharged from the outlet of the stretching portion 5 and both ends (both sides) of the film held by the gripping portion are trimmed, (Winding roll) to form a winding body of a long warp stretched film. Further, the trimming may be performed as necessary.

Further, before winding the long oblong stretched film, for the purpose of preventing blocking between the films, the masking film may be wound over the long oblong stretched film at the same time, or at least one of the long oblong stretched films It may be wound while tapes or the like are bonded to both ends. The masking film is not particularly limited as long as it can protect the long warp stretched film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.

Further, before winding the long warp stretched film, a portion (projection) bulging more than the film surface, called a knurling portion or an embossing portion, is formed on both ends in the width direction of at least one surface (preferably both surfaces) Thereby preventing the films from being blocked from each other when the film is wound. Further, the height and shape of the knurled portion may be different at both end portions in the width direction (may be asymmetric).

(Details of extension section)

Next, the elongating unit 5 will be described in detail. Fig. 2 is a plan view schematically showing an example of the rail pattern of the extending portion 5. Fig. However, this is merely an example, and the configuration of the extending portion 5 is not limited to this.

The long oblong stretched film in the present embodiment is produced by using a tenter stretchable tenter (warp stretching machine) as the stretching portion 5. This tenter is a device for heating a long film to an arbitrary stretchable temperature and obliquely stretching it. This tenter has a plurality of wave cores Ci · Co (see FIG. 2 (a)) for traveling along the rails (Ri · Ro) and the pair of rails Only one gripping region is shown). Details of the heating zone Z will be described later. Each of the rails Ri and Ro is constituted by connecting a plurality of rail portions by connecting portions (the white circle in Fig. 2 is an example of a connecting portion). The wave earth Ci · Co is constituted by a clip holding both ends in the width direction of the film.

In Fig. 2, unrolling direction D1 of the long film forms a unrolling angle &amp;thetas; i between winding direction D2, unlike winding direction D2 of elongated oblong drawn film after stretching. The unwinding angle &amp;thetas; i can be arbitrarily set to a desired angle in a range exceeding 0 DEG and less than 90 DEG.

As described above, since the unwinding direction D1 and the winding direction D2 are different from each other, the rail pattern of the tenter is asymmetrical in the right and left direction, and the conveying path of the film is curved in the middle. Then, the rail pattern can be manually or automatically adjusted in accordance with the orientation angle?, Stretching magnification, and the like applied to the long obliquely drawn film to be produced. In the warp stretching machine used in the manufacturing method of the present embodiment, it is preferable that the positions of the rail portions and the rail connecting portions constituting the rails Ri and Ro are freely set and the rail pattern can be arbitrarily changed.

In the present embodiment, the wave earth Ci · Co of the tenter is driven at a constant speed while maintaining a certain distance from the front and rear wave earths Ci · Co. The traveling speed of the wave earth Ci · Co can be appropriately selected, but is usually 1 to 150 m / min. In the present embodiment, as described later, it is preferable that the film is heated to be surely heated in the transport direction to give a temperature change, and 20 to 100 m / min in consideration of the productivity of the film. The difference in running speed of the pair of right and left wave cushions Ci and Co is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the running speed. This is because if there is a difference in traveling speed between the left and right sides of the film at the exit of the drawing process, wrinkles and unevenness at the exit of the drawing process occur, and therefore it is required that the speed difference between the left and right wave coils Ci · Co be substantially the same Because. In a general tentering machine or the like, there is a speed variation occurring on the order of seconds or less depending on the period of the teeth of the sprocket for driving the chain, the frequency of the drive motor, etc., This does not apply to the speed difference described in Fig.

In the warp stretching machine used in the production method of the present embodiment, a large bending rate is often found in a rail that restricts the trajectory of the crushing strip, particularly at a position where the conveyance of the film becomes oblique. In order to avoid interference between waveguides due to abrupt bending, or local concentration of stress, it is preferable to make the locus of the waveguide curved at the bent portion.

As described above, the oblique stretching tenters used for imparting the oblique directional orientation to the long film can change the orientation angle of the film freely (material) by variously changing the rail pattern, It is preferable that the tenter is capable of orienting the film in the film widthwise direction evenly and horizontally with high accuracy and controlling the film thickness and retardation with high precision.

Next, the drawing operation in the stretching section 5 will be described. Both ends of the long film are gripped by the left and right wave cores Ci · Co and transported in the heating zone Z in accordance with travel of the wave earth Ci · Co. The left and right wave cores Ci and Co are opposed to each other in a direction substantially perpendicular to the advancing direction of the film (the unwinding direction D1) at the entrance portion (position A in the drawing) of the stretching portion 5, Left and right asymmetric rails (Ro · Ro), respectively, and the film gripped at the exit portion (position B in the drawing) at the end of drawing is opened. The film released from the wave earth Ci · Co is wound on the winding core in the film winding unit 8 described above. The pair of rails Ri and Ro each have an endless continuous track and the waveguide Ci · Co that opens the grip of the film at the outlet of the tenter travels the outer rail and returns to the inlet portion .

At this time, since the rails Ri and Ro are asymmetric in the left and right directions in FIG. 2, the left and right wave fringes Ci and Co that are opposed to each other at the position A in the drawing travel on the rails Ri and Ro Therefore, the waveguide Ci running on the rail Ri side (in the course side) has a positional relationship that precedes the waveguide Co running on the side of the rail Ro (outcourse side).

That is, among the wave cores Ci and Co that were opposed to each other in the direction substantially perpendicular to the unwinding direction D1 of the film at the position A in the drawing, one waveguide Ci was positioned at the position B , The straight line connecting the waveguide (Ci · Co) is inclined at an angle θL with respect to a direction substantially perpendicular to the winding direction D2 of the film. With the above cauterization, the long film is obliquely elongated at an angle &amp;thetas; L with respect to the width direction. Here, the term &quot; substantially perpendicular &quot;

Next, details of the heating zone Z will be described. The heating zone Z of the stretching section 5 is constituted by a preheating zone Z1, a stretching zone Z2 and a heat fixing zone Z3. In the stretching section 5, the film held by the waveguide Ci 占 폚 passes through the preheating zone Z1, the stretching zone Z2, and the heat fixing zone Z3 in this order. In the present embodiment, the preheating zone Z1 and the stretching zone Z2 are partitioned by partition walls, and the stretching zone Z2 and the heat fixing zone Z3 are partitioned by partition walls. In addition, a partition wall may be appropriately provided in each zone of the preheating zone Z1, the stretch zone Z2, and the heat fixing zone Z3 (the inside of each zone may be further divided into partitions).

The preheating zone Z1 is a zone in which the waveguide Ci · C0 holding both ends of the film at the entrance of the heating zone Z travels with a constant interval in the left and right (in the film width direction) Lt; / RTI &gt;

The stretching zone Z2 refers to a section from the beginning of the interval between the waveguides Ci and Co holding the both ends of the film to a predetermined interval. At this time, oblique stretching is performed as described above, but if necessary, stretching may be performed in the longitudinal direction or the transverse direction before and after the oblique stretching. That is, in the stretching zone Z2, while both ends in the width direction of the film are gripped by the pair of waveguides Ci and Co, the one waveguide Ci is relatively advanced and the other waveguide Co The film is transported with a relatively delayed time and an oblique stretching step of stretching the film in the oblique direction with respect to the width direction is performed by bending the transport path of the film in the middle.

The heat fixing zone Z3 refers to a section for fixing the optical axis (slow axis) of the obliquely drawn film after the oblique stretching step in the stretching zone Z2. That is, in the heat fixing zone Z3, a heat fixing step for fixing the optical axis of the obliquely drawn film is performed. In the heat fixing zone Z3, the wave earths Ci and Co at both ends run parallel to each other. Thereby, the optical axis of the obliquely-drawn film is fixed.

The stretched film may pass through a section (cooling zone) where the temperature in the zone is set to be equal to or lower than the glass transition temperature Tg (占 폚) of the thermoplastic resin constituting the film after passing through the heat fixing zone Z3.

The temperature of the preheating zone Z1 is from Tg to Tg + 60 占 폚, the temperature of the stretching zone Z2 is from Tg to Tg + 50 占 폚, the temperature of the heat fixing zone Z3 and the temperature of the cooling zone Is preferably set to Tg-40 to Tg + 30 占 폚.

The lengths of the preheating zone Z1, the stretch zone Z2 and the heat fixing zone Z3 can be appropriately selected and the length of the preheating zone Z1 relative to the length of the stretch zone Z2 is usually 50 to 200% , And the length of the heat fixing zone Z3 is usually 50 to 150%.

When the width of the film before stretching is W0 (mm) and the film width after stretching is W (mm), the stretch ratio R (W / W0) in the stretching step is preferably 1.1 to 3.0, Is 1.15 to 2.0. When the stretching magnification falls within this range, thickness irregularity in the width direction of the film becomes small, which is preferable.

[Regarding the temperature control of the film in the warp stretching process]

Next, the temperature control in the transport direction (longitudinal direction) of the film in the stretching zone Z2 in which the oblique stretching process is performed will be described. In the present embodiment, in the oblique stretching process, the temperature of the film is made different at the starting point and the end point of the arc on the arc of the conveying path for elongating in the oblique direction. In the following description, the curvature of the conveying path means that the conveying path is curved in an arc, that is, the conveying path is smoothly curved.

3 schematically shows a state in which the conveying path of the film in the stretching section 5 (indicated by a thick solid line in the figure) is bent on the way. As described above, the transport path of the film is adjusted by adjusting the position and the degree of curvature (curvature) of the rails Ri and Ro on which the pair of wave fringes Ci and Co that grip both ends in the width direction of the film travel, Can be changed. The "starting point of bending of the conveying path for drawing in the oblique direction" is a point on the most upstream side of the curved portions Q1 and Q2 curved in an arc in order to perform oblique drawing in the rails Ri and Ro It indicates the time point when an arbitrary point of the film conveyed on the line connecting P11 and P21 reaches. The term &quot; end point of bending &quot; refers to a point on the line connecting the points P12 and P22 on the most downstream side of the curved portions Q1 and Q2 on the rail (Ri · Ro) .

When the film reaches the line connecting the points P11 and P21, the conveying direction of the film starts to bend in an arc shape there and changes in the film discharging direction after the oblique drawing. From this, it can be said that the &quot; starting point of bending of the conveying path for drawing in the oblique direction &quot; means that the direction of the vector representing the transport direction of the film starts to change from the direction before the oblique drawing toward the discharging direction after the oblique drawing have. The term &quot; end point of bending &quot; may be a time point at which the direction of the vector representing the transport direction of the film coincides with the discharge direction after the warp stretching.

On the upstream side of the line connecting the points P11 and P21 on the upstream side in the transport direction, transverse stretching (pre-stretching) may be performed on the film as shown in the drawing, or transverse stretching may not be performed.

3 shows an example in which the curvature of the conveying path starts and ends at the same time in the width direction of the film (with respect to all the points in the width direction), but depending on the length and the degree of curvature of the curved portions Q1 and Q2 , The curvature of the conveying path is started or terminated on the side of the width direction of the film (on the waveguide (Ci) side preceding the warp stretching) and on the retard side (on the waveguide (Co) side delaying during warp stretching) The timing may be different. In this case, "the starting point of bending of the conveying path for oblique stretching" refers to a point at which the leading side of the film and the end of the delay side reach the line connecting the points P11 and P21 more quickly, Refers to a time point at which the end on the leading side or the delay side of the film arrives late by the line connecting the points P12 and P22. In the following description, the section from the start (starting point) to the ending (starting point) of the bending is also referred to as a region where oblique stretching is performed or a warp stretching region.

Fig. 4 shows another illustrated manner of the stretching section 5. Fig. In the stretching zone Z2, the rails Ri and Ro may be connected in a straight line as shown in the figure, but in this case also, in reality, the conveying path of the film may be curved Thereby causing oblique stretching. Therefore, in this drawing, the conveying path of the film in the stretching section 5 is as shown by an arrow of a thick solid line, and at the position on the upstream side of the line connecting the points Q11 and Q12, And the bending of the arc on the conveying path is terminated at a position on the downstream side of the line segment. The points Q11 and Q12 indicate points at which the curvatures of the curved portions Q1 and Q2 shown in Fig. 3 become the maximum, or intermediate points in the conveying direction of the curved portions Q1 and Q2. 4, the position at which the curvature of the carrying direction starts (the line connecting the points P11 'and P21') on the upstream side of the line connecting the points Q11 and Q12 is the point P11 · P21 in Fig. 3 (Points connecting the points P12 'and P22') at which the curvature of the conveying direction is terminated at the downstream side of the line segment connecting the points Q11 and Q12 to the points P12 and P22 of FIG. 3 The temperature control in the film transport direction of the present embodiment can be applied.

(Method of Temperature Control in Film Transfer Direction)

Hereinafter, a specific method of temperature control in the transport direction of the film in the warp stretching process will be described.

5 schematically shows an example of the temperature control of the stretching portion 5 in the film transport direction. In the example of the diagram, in the oblique stretching region, the temperature distribution of the film is controlled in two stages in the transport direction. More specifically, the temperature of the film on the upstream side in the transport direction in the obliquely-drawn region is made higher than the temperature of the film on the downstream side. That is, in the oblique stretching region, the temperature of the film at the end of bending of the conveying path is made lower than the film temperature at the beginning of bending. This temperature control in the transport direction can be realized by arranging two heating units 11 · 12, which are long in the width direction of the film and different in output (heating ability), in the transport direction in the oblique stretching region. However, the output of the heating unit 11 is larger than the output of the heating unit 12.

The heating portion 11 占 2 may be disposed on at least one of the upper surface side and the lower surface side of the film. The heating unit 11 占 2 can be constituted by a nozzle for ejecting hot air or an infrared heater. For example, the amount of the hot air blown from the nozzle may be increased in the heating portion 11 as compared with the heating portion 12, or the temperature of the hot air may be made higher in the heating portion 11 than in the heating portion 12, The number of watts) is made higher in the heating section 11 than in the heating section 12, a temperature distribution as shown in Fig. 6 can be realized. However, from the viewpoint of suppressing the vibration of the film as much as possible, it is preferable to change the temperature (the temperature of hot air, the output of the heating section) of the heating section 11 · 12. In the present embodiment, the heating section 11 has only one heating area 11a for heating the film, and the heating section 12 has only one heating area 12a for heating the film. These heating regions 11a and 12a are constituted by, for example, an infrared heater. In the present embodiment, the temperature of the film in the transport direction is controlled by using the plurality of heating units 11, 12, but the number of the heating units may be limited. That is, the heating temperature may be changed in the transport direction of the film by a single heating unit.

As a means for changing the film temperature in the transport direction, means for heating or cooling the opposite side on the upstream side or the downstream side may also be adopted. Examples of the means include a method in which air having a different temperature from the upstream side and the downstream side is sprayed or the upstream side and the downstream side are heated by heating the upstream side only with a constant temperature or using a heater having a different temperature Means, and is not particularly limited.

By making the temperature of the film at the end of the bending of the conveying path lower than the film temperature at the beginning of bending in the oblique stretching area as described above by utilizing the shrinkage behavior of the film itself as the oblique stretching progresses, It is difficult to relax in the width direction, and the tension of the film at the time of oblique stretching can be stabilized. Thereby, it is possible to reduce the vibration of the film at the time of oblique stretching, and it is possible to reduce occurrence of uneven heating in the conveying direction of the film by this vibration. As a result, it is possible to reduce occurrence of non-uniformity of in-plane retardation Ro in the transport direction of the film. Accordingly, even when the obliquely-stretched film thus produced is applied to a circularly polarizing plate for preventing reflection of external light of the OLED, the unevenness in color due to the non-uniformity of the in-plane retardation Ro in the conveying direction can be reduced.

Here, when the film temperature at the beginning of the bending in the oblique stretching region is T1 (占 폚) and the temperature of the film at the end of bending is T2 (占 폚), the film is imparted with a temperature change in the transport direction From the viewpoint of stabilizing the tightness of the film and reducing the vibration of the film and reliably reducing the in-plane retardation Ro in the transport direction,

(T1-T2) ≥1 ° C

, &Lt; / RTI &gt;

(T1-T2) &gt; 2 [deg.] C

Is more preferable.

Although the upper limit of T1-T2 is not specifically defined, if T1-T2 becomes too large, that is, if T2 becomes too low, there is a fear that T2 is out of the proper temperature range at the time of elongation. , The film may be broken at the time of stretching. Therefore, the upper limit of T1-T2 may be set within a range in which film breakage does not occur at the time of stretching, and for example,

(T1-T2) &lt; = 40 DEG C

It can be said that it is.

The film temperature can be measured with a non-contact temperature sensor. Specifically, the temperature of the film during drawing can be measured using a heat-resistant type non-contact temperature sensor (IRtec Rayomatic 14, manufactured by Eurotron Co., Ltd.). The heating and cooling temperature ranges are not particularly limited, and heating or cooling may be performed in a temperature range where desired in-plane retardation can be ensured.

In the example of Fig. 5, the film temperature is controlled in two stages in the transport direction in the oblique stretching region, but it may be changed to three or more stages. That is, the film temperature may be changed so as to be lowered in three steps (from the upstream side to the downstream side in the transport direction) (see FIGS. 9 and 10), or may be changed to a larger number of steps. Thus, by changing the film temperature in three or more stages in the transport direction, the temperature of the film in the transport direction can be finely controlled, so that the tension of the film at the time of oblique stretching can be further stabilized. As a result, the vibration of the film can be reduced, and the in-plane retardation Ro in the transport direction can be reliably reduced.

Further, if the temperature T2 of the film at the end of the bending in the oblique stretching region is lower than the temperature T1 (占 폚) of the film at the start of the bending, the temperature change therebetween may be any change. For example, as shown by a1 in Fig. 6, the film temperature may be constant (T1) for some time from the start of bending, and the film temperature may be decreased from the middle to T2. (Continuously) decreasing from T1 to T2. After the initiation of bending, as in the case of a4, the film temperature is immediately decreased from T1, and after a predetermined time elapses from the temperature constant, it may be decreased again and changed to T2 .

From the above, it can be said that in the oblique stretching region, the temperature of the film may be changed stepwise or continuously in the transport direction.

Also, as in a5, the film temperature may be decreased from T1 to T2 immediately, and the film temperature may be maintained at T2 from the bending to the end of bending.

Further, during the period from the start of bending to the end of bending, the film temperature may temporarily become low. More specifically, assuming that a temperature lower than T1 and T2 is T3 (占 폚), the film temperature may be changed in the order of T1, T3, and T2 from the start of bending to the end of bending as in a6. Further, it is preferable that DELTA T1 = T1-T2 and DELTA T2 = T2-T3, DELTA T2 &amp;le; 0.5 DELTA T1 is more preferable, DELTA T2 DELTA DELTA DELTA T1 is more preferable and DELTA T2 DELTA DELTA T1 DELTA DELTA T1 is more preferable Do.

Further, in the oblique stretching region, if the temperature of the film can be controlled so that the temperature of the film at the end of bending becomes lower than the starting point of the bending, the method is not limited to the heating by the above-mentioned heating portion. For example, it is possible to control the temperature of the film in the oblique stretching region similar to the present embodiment, even if a cooler for blowing cooling air is used alone or in combination with a heating unit.

(For temperature control in the film width direction)

Fig. 7 schematically shows another example of the temperature control of the film. As shown in the drawing, the temperature of the film may be changed in the width direction by applying the temperature in the transport direction in the oblique stretching region. That is, for example, the heating section 11 and the heating section 21 are arranged side by side in the width direction and the film temperature is set in the width direction (the area on the upstream side in the warp stretching region) Change. The heating section 21 may be composed of the same nozzle or infrared heater as the heating section 11. [ However, the output of the heating unit is, for example, the heating unit 11> the heating unit 21> the heating unit 12.

As described above, by changing the film temperature not only in the transport direction but also in the width direction, it is possible to reduce the fluctuation of the in-plane retardation Ro in the width direction of the film, and as a result, It becomes possible to further reduce.

In Fig. 7, the heating unit 11 占 2 is arranged to heat the film so that the retarded side in the width direction has a film temperature higher than that in the preceding side. However, in both the retarded side and the preceding side, May be set according to the rail position (start point and end point of bending) and the degree of bending of the oblique stretching region. That is, as long as the fluctuation of the in-plane retardation Ro in the width direction of the film can be reduced, either the retardation side or the preceding side of the film may be increased in temperature.

Fig. 8 schematically shows another example of the temperature control of the film. As shown in the drawing, the film temperature may be changed in the width direction over the entire transport direction of the oblique stretching region. That is, the heating portions 11 and 21 may be arranged side by side in the width direction and the heating portions 21 and 12 may be arranged side by side also in the downstream side region in the region on the upstream side in the oblique stretching region. In this case, the tension of the film at the time of warping and stretching can be stabilized in both the carrying direction and the width direction, and therefore it is possible to reliably reduce the in-plane retardation Ro across the entire surface of the film.

As means for changing the film temperature in the width direction, a means for heating or cooling the opposite side of the retarded side or the preceding side may be adopted. As the means, it is preferable to use a method in which a wind having a different temperature on the delay side and the preceding side is sprayed, or only the temperature of the wind is constant and only one of the delay side and the preceding side is heated by a heater, Heating, and the like, and is not particularly limited.

(Preferred arrangement example of the heating part)

Next, a preferable arrangement example of the heating portion in the oblique stretching region will be described. In the following, the case where the heating units with the same output are arranged in the width direction will be described, but the case where the heating units with different outputs are arranged in the width direction can be similarly considered. In the following description, the output of the heating section is the heating section 11 (heating area 11a)> the heating section 12 (heating area 12a)> the heating section 13 (heating area 13a) .

As shown in Fig. 9, in the oblique stretching region, a plurality of heating units 11 占 12 占 3 are arranged in this order from the upstream side to the downstream side in the carrying direction, and a plurality of heating units 11 占) Are arranged side by side in the width direction, a plurality of heating portions 12 占 2 are arranged side by side in the width direction, a plurality of heating portions 13 占 3 are arranged side by side in the width direction, The heating regions of the heating sections 11 to 13 are positioned in both the width direction and the transport direction of the film. In this case, the gap S of the heating portion 11 · 11 adjoining in the width direction, the gap portion S of the heating portion 12 · 12, the gap portion S of the heating portion 13 · 13 Is located on the same transport path of the film, the portion of the film that takes its transport path is not efficiently heated by the heating portion 11 or the like as compared with the other portions, so that the in- Variation occurs.

Thus, as shown in Fig. 10, for example, a virtual line V (a non-heated region) in which gap portions S (unheated regions) of two heating portions (heating regions) adjacent in the width direction are connected from the upstream side to the downstream side It is preferable to arrange the heating units 11 to 13 in the transport direction so as to be shifted (to cause inconsistency) from the transfer locus of the arbitrary point of the film (see the broken line), and heat the film. In this case, there is no case in which an arbitrary point on the film always passes directly under or over the gap S and is transported without being efficiently heated. Therefore, fluctuation of the in-plane retardation Ro in the width direction due to heating unevenness can be reduced.

11 is a perspective view showing another configuration example of the heating section 11, and Fig. 12 is a plan view of the heating section 11. Fig. As shown in these figures, the heating section 11 may be formed of a nozzle having a plurality of jetting orifices H for jetting hot air as a heating region and having a plurality of jetting outlets H arranged in one direction. Then, the heating unit 11 and the heating unit (the output is different) having the same configuration as this heating unit 11 may be arranged in the transport direction to heat the film. In this case also, each jetting port H (plural heating zones) is positioned in both the width direction and the transport direction of the film. At this time, if the seam Bo located between the spouting holes H and H adjacent in the width direction is located on the same transport path of the film, as in the case of the arrangement of Fig. 9, , A variation occurs in the in-plane retardation Ro in the width direction of the film.

13, the imaginary line V in which the joints Bo (unheated regions) of the plurality of heating units 11 to 13 are connected from the upstream side to the downstream side is the arbitrary line of the film It is preferable to arrange the plurality of heating portions 11 to 13 in the transport direction so as to be deviated from the transporting trajectory of the point of the point (see the broken line in detail) so as to heat the film. In this case, since the joint Bo is scattered in a zigzag manner in the carrying direction, there is no case in which an arbitrary point on the film is always conveyed without being heated efficiently by passing directly under or over the seam Bo. This makes it possible to reduce variations in in-plane retardation Ro in the width direction due to heating unevenness.

10, heating units (heating units 11 to 13) having only one heating zone and heating nozzles (heating units 11 to 13) having a plurality of heating zones as shown in Fig. 13, 13) may be combined to heat the film.

As described above, in the case of using the heating portion having at least one heating region and arranging the heating portion such that the heating region is positioned in both the width direction and the conveying direction of the film and the film is heated, It is preferable that the hypothetical line V connecting the non-heated regions between the adjacent two heating regions from the upstream side to the downstream side in the transport direction is located so as to be shifted from the transportation locus of any point of the film. At this time, the unheated region may include a gap portion S between two heating regions adjacent to each other in the width direction, and a joint B between the jetting out ports H as two heating regions adjacent in the width direction ) May be included.

(Preferred Configuration Example of the Drawing Portion)

As shown in Fig. 14, in the elongating section 5 (particularly the oblique stretching region), an adjustment section M for adjusting the angular positions of the rails Ri and Ro on which the pair of waveguides Ci and Co run, (A rail moving unit and a facility accompanying the rail moving unit) are provided, respectively. That is, the rails Ri and Ro (for example, the bent portions Q1 and Q2) are slid outward or inward by the adjusting portion M or rotate in the plane along the film transport direction. When the adjusting section M is arranged asymmetrically (non-line symmetry in plan view) in the delay side and the preceding side with respect to the conveying direction before the oblique stretching (the direction of the axis AX) Even if the heating section 11 is disposed symmetrically on the delay side and the preceding side, the flow of heat in the furnace is changed, and the staying temperature is changed according to the position in the furnace.

15, in the oblique stretching region, the equipment section Y including the plurality of heating sections 11 and the adjusting section M is moved in the direction of the delay before the oblique stretching of the film So that the oblique stretching is performed. Concretely, as the adjustment section M, the pseudo adjustment section M2 is arranged asymmetrically in the delay side and the preceding side in addition to the adjustment section M1 arranged asymmetrically in the delay side and the preceding side in Fig. 14, Thereby, the four adjusting portions M are made symmetrical with respect to the direction along the axis AX on the delay side and the preceding side. At this time, it is assumed that the heating unit 11 is positioned symmetrically with respect to the direction along the axis AX. By symmetrically arranging the equipments Y in this manner, the heat flow (heat distribution) in the furnace 5 is made symmetrical with respect to the direction along the axis AX, and the residence temperature in the furnace can be made uniform. The pseudo adjusting unit M2 may have a function of adjusting the positions of the rails Ri and Ro as in the case of the adjusting unit M1 or may be a simple dummy having no such function.

The symmetrical arrangement of the equipment part Y can also be applied to a configuration in which the temperature of the film is controlled without providing a plurality of heating parts 11. As the film temperature control, for example, there is a method of controlling the film temperature by using a cooler, and a method of controlling the film temperature by controlling the exhaustion of the furnace 5 in the furnace as will be described below.

In addition, as shown in Fig. 16, for example, in a furnace of a stretching section 5, in particular, in an oblique stretching region in which a conveying path is bent, heat is liable to be entrapped in the furnace at the delay side of the bent portion. Therefore, as shown in Fig. 17, the temperature distribution in the width direction during the transportation of the film is set such that the pair of wave coils (Co · Ci) travels in the entire warp stretched region in the furnace of the stretching portion It is preferable to exhaust the inside of the furnace (asymmetrically) so as to be symmetrical with respect to the center between the rail Ro on the delay side and the rail Ri on the front side so as to be symmetrical on the delay side and the preceding side. In the oblique stretching region, the temperature distribution in the furnace is symmetrical on the retard side and the preceding side, so that the film can be uniformly heated in the carrying direction and the width direction to further reduce the in-plane retardation Ro in the entire film.

As a method of exhausting in which the temperature distribution is symmetrical, the exhausting ability (exhausting amount per unit time) of the exhausting portion E1 on the leading side in the furnace may be made higher than the exhausting ability of the exhausting portion E2 on the retarding side. Specifically, the position of the exhaust port on the preceding side may be closer to the rail side than the position of the exhaust port on the delay side, or the area of the exhaust port on the preceding side may be larger than the area of the exhaust port on the delay side . Further, the air exhausted to the exhaust sections E1 and E2 may be returned to the inside of the furnace section 5 to circulate the inside of the furnace section 5, and may not be circulated. Further, if the volume of the stretching zone Z2 in which the oblique stretching is performed is made larger on the delay side than on the preceding side, the heat is more difficult to be trapped on the delay side and the temperature distribution can be made uniform.

(Other)

The film to be oblique drawn in the present embodiment may be a film containing a cellulose resin (such as the above-mentioned cellulose ester resin). In this case, nonuniformity of the in-plane retardation Ro in the transport direction of the film can be reduced by obliquely stretching the film containing the cellulose-based resin while performing the above-described temperature control in the transport direction.

In the oblique stretching step, the film may be conveyed at a speed of 1 to 150 m / min. However, in the oblique stretching region, the temperature is reliably changed in the conveying direction by heating the film, , The transporting speed of the film is preferably 10 to 120 m / min, preferably 20 to 100 m / min.

In the oblique stretching region, the stretching magnification of the film that is obliquely stretched is preferably 1.05 to 2.5 times, more preferably 1.4 to 2.3 times, and further preferably 1.6 to 2.1 times. Here, the stretching magnification is the ratio of the elongation in the orientation axis direction (the length E1 (mm) in Fig. 3) / (the starting point of the stretching (the pre- (The length E2 (mm) in Fig. 3) x 100 (%) at the start of the transverse stretching. When the stretching magnification becomes higher, the relaxation behavior at the time of contraction in the transverse direction The film tends to generate vibration, and the in-plane retardation Ro is easily generated in the transport direction, so that the temperature control of the above-described embodiment is very effective.

&Lt; Quality of long oblique stretched film >

In the long oblong stretched film obtained by the production method of the present embodiment, the orientation angle? Is inclined to a range of, for example, greater than 0 and less than 90 degrees with respect to the winding direction. In a width of at least 1300 mm, It is preferable that the variation of the in-plane retardation Ro is 2 nm or less and the variation of the orientation angle [theta] is less than 0.6 [deg.]. The in-plane retardation value Ro (550) of the long oblong stretched film measured at a wavelength of 550 nm is preferably in the range of 80 nm or more and 160 nm or less, more preferably 90 nm or more and 150 nm or less.

That is, in the long oblong stretched film obtained by the production method of the present embodiment, the fluctuation of the in-plane retardation Ro is preferably 2 nm or less and 1 nm or less at 1300 mm in the width direction. When the fluctuation of the in-plane retardation Ro is in the above range, a long oblong stretched film is bonded to the polarizer to form a circularly polarizing plate. When this is applied to an organic EL image display apparatus, Can be suppressed. In addition, when a long oblong stretched film is used as a retardation film for a liquid crystal display device, for example, the display quality can be made good.

In the long oblong stretched film obtained by the manufacturing method of the present embodiment, the variation of the orientation angle? Is preferably less than 0.6 deg., Preferably less than 0.4 deg., At least at 1300 mm in the width direction, desirable. When a long oblong stretched film having a variation of the orientation angle? Of more than 0.6 is bonded to a polarizer to form a circularly polarizing plate and this film is provided in an image display apparatus such as an organic EL display device, light leakage occurs, .

The in-plane retardation Ro of the long oblong drawn film obtained by the production method of this embodiment is selected by the design of the display device to be used. 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 plane perpendicular to the slow axis in the plane (Ro = (nx-ny) xd )to be.

The average thickness of the long oblong drawn film obtained by the production method of the present embodiment is preferably 1 to 400 占 퐉, preferably 10 to 200 占 퐉, more preferably 10 to 60 占 퐉, particularly preferably Lt; / RTI &gt; Further, the thickness unevenness in the width direction of the long oblong drawn film is preferably not more than 2 탆, more preferably not more than 1 탆, because it affects the winding ability of the winding.

The long oblong stretched film obtained by the production method of the present embodiment may have a functional layer on its surface. The functional layer may be an antireflection layer, a low refractive index layer, a hard coating 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 absorption layer, A heat resistant layer, a magnetic layer, an oxidation preventing layer, an overcoat layer, and the like.

<Circular Polarizer>

In the circular polarizer of the present embodiment, a polarizing plate protective film, a polarizer and a lambda / 4 film are laminated in this order, and the angle between the slow axis of the lambda / 4 film and the absorption axis (or transmission axis) . When the circular polarizer of the present embodiment is used in an organic EL display device, the polarizer protective film, the polarizer, and the? / 4 film are the same as the protective film 313, the polarizer 311, the? / 4 film 316, Respectively. In the present embodiment, it is preferable that a long polarizer protective film, a long polarizer, and a long? / 4 film (long obliquely stretched film) are laminated in this order.

When the circular polarizer of the present embodiment is used in a liquid crystal display device, the polarizer protective film, the polarizer, and the? / 4 film are the same as the protective film 506, the polarizer 501, the? / 4 film 503 Respectively. A protective film 506 and a polarizer 501 are disposed on the outer side (viewing side) of the display cell 401 and a lambda / 4 film 503 is formed on the outside of the polarizer 501 The linearly polarized light emitted from the display cell 401 and transmitted through the polarizer 501 is converted into circularly polarized light or elliptically polarized light by the? / 4 film 503. Therefore, in the case where the observer observes the display image of the display device 400 by attaching the polarizing sunglasses, even when observing at an angle (the transmission axis of the polarizer 501 (perpendicular to the absorption axis) It is possible to observe the display image by guiding the component of the light parallel to the transmission axis of the polarizing sunglass to the observer's eye so that it is possible to suppress the display image from being hardly seen in accordance with the viewing angle.

The circular polarizer of the present embodiment can be produced by using a polarizer obtained by stretching polyvinyl alcohol doped with iodine or a dichroic dye and bonding it with a constitution of? / 4 film / polarizer. The film thickness of the polarizer is 5 to 40 占 퐉, preferably 5 to 30 占 퐉, and particularly preferably 5 to 20 占 퐉.

The polarizing plate can be manufactured by a general method. The alkali saponified? / 4 film is preferably bonded to one side of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a fully saponified polyvinyl alcohol aqueous solution.

The polarizing plate may be constituted by bonding a peeling film to 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 at the time of polarizing plate shipment, product inspection and the like.

<Organic EL Display Device>

18 is a cross-sectional view showing a schematic structure of an organic EL display device 100 as an OLED of the present embodiment. The configuration of the organic EL display device 100 is not limited to this.

The organic EL display device 100 is constituted by forming a circularly polarizing plate 301 on an organic EL element 101 through an adhesive layer 201. [ The organic EL element 101 has a metal electrode 112, a light emitting layer 113, a transparent electrode (such as ITO) 114, and a sealing layer 115 on the substrate 111 using glass or polyimide in this order Consists of. The metal electrode 112 may be composed of a reflective electrode and a transparent electrode.

The circularly polarizing plate 301 includes a quarter wave film 316, an adhesive layer 315, a polarizer 311, an adhesive layer 312, a protective film 313, and a cured layer 314 in this order from the organic EL element 101 side. And the polarizer 311 is sandwiched between the? / 4 film 316 and the protective film 313. The polarizer 311 is formed by laminating a? The polarizer 311 is bonded to the circular polarizer 311 such that the angle formed by the transmission axis of the polarizer 311 and the slow axis of the? / 4 film 316 including the long obliquely stretched film of the present embodiment is about 45 ° (or 135 °) (301).

The protective film 313 preferably has a cured layer 314 laminated thereon. The cured layer 314 not only prevents surface scratches of the organic EL display device 100 but also has the effect of preventing warping by the circularly polarizing plate 301. [ Also, an antireflection layer may be formed on the cured layer 314. The thickness of the organic EL element 101 itself is about 1 mu m.

When voltage is applied to the metal electrode 112 and the transparent electrode 114 in the above structure, electrons are injected into the light emitting layer 113 from the electrode that is the cathode of the metal electrode 112 and the transparent electrode 114, Holes are injected from the electrodes serving as the positive electrodes and recombined in the light emitting layer 113 so that the visible light rays corresponding to the light emitting characteristics of the light emitting layer 113 are emitted. Light generated in the light emitting layer 113 is directly or reflected by the metal electrode 112 and then is taken out to the outside through the transparent electrode 114 and the circularly polarizing plate 301.

Generally, in an organic EL display device, a light emitting element (organic EL element) is formed by sequentially laminating a metal electrode, a light emitting layer, and a transparent electrode on a transparent substrate. Here, the light emitting layer is a laminate of various organic thin films, for example, a stacked body of a hole injection layer including a triphenylamine derivative or the like and a light emitting layer containing a fluorescent organic solid such as anthracene, A multilayer body with an electron injecting layer including a hole injecting layer, a hole injecting layer, and a derivative, and a laminate of these hole injecting layers, a light emitting layer, and an electron injecting layer.

In the organic EL display device, holes and electrons are injected into the light emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by the recombination of the holes and the electrons excites the fluorescent substance, The light is emitted on the same principle as that of emitting light. The mechanism of recombination in the middle is similar to that of a general diode, and as can be expected from this, the current and the light emission intensity exhibit strong nonlinearity accompanied by rectification with respect to the applied voltage.

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

In the organic EL display device having such a structure, the light emitting layer is formed of a very thin film having a thickness of about 10 nm. Therefore, the light emitting layer almost completely transmits the light, like the transparent electrode. As a result, the light incident on the surface of the transparent substrate at the time of non-light emission, the light transmitted through the transparent electrode and the light-emitting layer and reflected by the metal electrode is again directed to the surface side of the transparent substrate, The display surface looks like a mirror surface.

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

That is, half of the external light incident from the outside of the organic EL element 101 by room illumination or the like is absorbed by the polarizer 311 of the circularly polarizing plate 301 at the time of non-emission of the organic EL element 101, Half of the light is transmitted as linearly polarized light, and enters the? / 4 film 316. The light incident on the? / 4 film 316 is incident on the? / 4 film 316 because the transmission axis of the polarizer 311 and the slow axis of the? / 4 film 316 intersect at 45 degrees (or 135 degrees) And is converted into circularly polarized light by passing through the film 316.

The circularly polarized light emitted from the lambda / 4 film 316 is inverted in phase by 180 degrees when it is mirror-reflected by the metal electrode 112 of the organic EL element 101, and is reflected as circularly polarized light in the reverse rotation direction. This reflected light is converted into linearly polarized light perpendicular to the transmission axis of the polarizer 311 (parallel to the absorption axis) by being incident on the lambda / 4 film 316, so that all of the reflected light is absorbed by the polarizer 311, . That is, by the circularly polarizing plate 301, reflection of external light in the organic EL element 101 can be reduced.

<Liquid Crystal Display Device>

19 is a cross-sectional view showing a schematic structure of a display device 400 as a liquid crystal display device of the present embodiment. The display device 400 is constituted by disposing a polarizing plate 402 on one side of the display cell 401.

In the case of a liquid crystal display device, the display cell 401 can be a liquid crystal cell in which a liquid crystal layer is sandwiched between a pair of substrates. Further, on the liquid crystal cell opposite to the polarizing plate 402, there is provided a polarizing plate 402, a separate polarizing plate disposed in a cross-Nicol state, and a backlight for illuminating the liquid crystal cell. have.

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. [ The front window 403 serves as an external cover of the display device 400, and is constituted by, for example, a cover glass. Between the front window 403 and the polarizing plate 402, a filler 404 containing, for example, an ultraviolet curable resin is filled. An air layer is formed between the front window 403 and the polarizing plate 402. When the front window 403 and the polarizing plate 402 are reflected from the interface between the air layer and the front window 403, May be deteriorated in some cases. However, since the air layer is not formed between the front window 403 and the polarizing plate 402 by the filler 404, deterioration of the visibility of the display image due to reflection of light at the interface can be avoided.

The polarizing plate 402 has a polarizer 501 which transmits a predetermined linearly polarized light. The? / 4 film 503 and the cured layer 504 including the ultraviolet curing type resin are arranged in this order on the one surface side (the side opposite to the display cell 401) of the polarizer 501 via the adhesive layer 502 Respectively. A protective film 506 is bonded to the other surface side (the display cell 401 side) of the polarizer 501 through an adhesive layer 505. [

The polarizer 501 is obtained, for example, by staining a polyvinyl alcohol film with a dichroic dye and stretching it at a high magnification. After the polarizer 501 is subjected to an alkali treatment (also referred to as a saponification treatment), a lambda / 4 film 503 is bonded to one side via an adhesive layer 502 and a protective film 506 is bonded to the other side of the adhesive layer 505, Respectively.

Assuming that the thickness of the polarizer 501 is B 占 퐉, from the viewpoint of thinning of the polarizing plate 402,

1 mu m < B &lt;

, &Lt; / RTI &gt;

1 mu m < B &lt;

Is more preferable.

The adhesive layer 502 占 505 is, for example, a layer containing a polyvinyl alcohol adhesive (PVA adhesive, waterbath), but may be a layer containing an ultraviolet curable adhesive (UV adhesive). These adhesives are liquids in a state of being applied to the adhesive surface, and are cured by drying or ultraviolet irradiation after application, thereby adhering them. That is, the adhesive layer 502 · 505 adheres the polarizer 501 and the λ / 4 film 503, and the polarizer 501 and the protective film 506, respectively, due to the state change from the liquid phase. As described above, the adhesive layer 502 占 505 is provided with a pressure-sensitive adhesive layer (a pressure-sensitive adhesive layer on the sheet having a pressure-sensitive adhesive on the substrate) and a pressure-sensitive adhesive layer .

The? / 4 film 503 is a layer which gives an in-plane retardation of about 1/4 of the wavelength of transmitted light. In the present embodiment, for example, the? / 4 film 503 contains a cellulose resin (cellulose-based polymer). The? / 4 film 503 may contain a polycarbonate resin (polycarbonate-based polymer) instead of the cellulose-based polymer, or may include a cycloolefin-based resin (cycloolefin-based polymer). However, from the viewpoint of chemical resistance, it is preferable that the? / 4 film 503 contains a cellulose-based polymer or polycarbonate-based polymer.

The? / 4 film 503 is a? / 4 film of a thin film having a thickness of 10 μm to 70 μm. The angle (angle of intersection) between the slow axis of the λ / 4 film 503 and the absorption axis of the polarizer 501 is 30 ° to 60 ° so that the linearly polarized light from the polarizer 501 becomes λ / 4 film 503 into circularly polarized light or elliptically polarized light.

The cured 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 an optical film including, for example, a cellulose-based resin (a cellulosic polymer), an acrylic resin, a cyclic polyolefin (COP), and a polycarbonate (PC). Although the protective film 506 is provided as a film for simply protecting the back side of the polarizer 501, it may be provided as an optical film serving also as a retardation film having a desired optical compensation function.

In the case of a liquid crystal display device, a separate polarizing plate disposed on the side opposite to the polarizing plate 402 with respect to the display cell 401 (liquid crystal cell) is constituted by sandwiching the surface of the polarizing plate with two optical films. As the polarizer and the optical film, the same polarizer 501 and protective film 506 as the polarizer 402 can be used.

Here, the polarizer 501 and the? / 4 film 503 may each have a long shape. In this case, it is preferable that the slow axis of the lambda / 4 film 503 be inclined by 30 DEG to 60 DEG with respect to the longitudinal direction of the lambda / 4 film 503. In this case, And a long polarizing plate 402 can be manufactured by joining the polarizing plate 501 and the roll polarizing film 501 in a so-called roll-to-roll manner. Thus, The productivity can be dramatically improved and the yield can be greatly improved as compared with the case where the polarizing plate 402 is manufactured by a batch process.

Further, an easy adhesion layer for improving the adhesiveness of the? / 4 film 503 may be provided on the adhesive layer 502 side of the? / 4 film 503. The adhesion facilitating layer is formed by performing an adhesion facilitating treatment on the adhesive layer 502 side of the? / 4 film 503. Examples of the adhesion facilitating treatment include a corona discharge treatment, a plasma treatment, a frame treatment, an itro treatment, a glow treatment, an ozone treatment, a primer coating treatment and the like. Among these adhesion facilitating treatments, from the viewpoint of productivity, the corona treatment and the plasma treatment are preferable as the adhesion facilitating treatment.

<Examples>

Hereinafter, specific examples and embodiments relating to the production of the warp stretched film according to the present embodiment will be described together with a comparative example. The present invention is not limited to the following examples. In the following, the notation &quot; part &quot; or &quot;% &quot; is used, and unless otherwise stated, they are expressed as &quot; parts by mass &quot;

<Fabrication of Fabric Film>

Long films 1 to 2 as a raw film were produced by the following method.

(Long film 1)

The long film 1 is a cellulose ester based resin film and was produced by the following production method.

&Quot; Fine particle dispersion liquid &

Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by mass

ethanol 89 parts by mass

The mixture was stirred with a dissolver for 50 minutes, and then dispersed with mannitol. Thus, a fine particle dispersion 1 was prepared.

&Lt; Particulate additive liquid &

On the basis of the following composition, the fine particle dispersion was slowly added to a dissolution tank containing methylene chloride while stirring sufficiently. And dispersed by an attritor so that the particle diameter of the secondary particles became a predetermined value. The solution was filtered with Fine Mat NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle addition liquid 1.

Methylene chloride 99 parts by mass

Fine Particle Dispersion 1 5 parts by mass

«Juodope»

To prepare a main dope liquid having the following composition. First, methylene chloride and ethanol were added to the pressure-dissolving tank. Cellulose acetate was added to the pressurized dissolution tank containing the solvent while stirring. The solution was heated and completely dissolved with stirring, and the solution was filtered using Azumi Rosy No.244 manufactured by Azumi Co., Ltd. to prepare a main dope solution. As the sugar ester compound and the ester compound, the compound synthesized by the following synthesis examples was used.

&Quot; Composition of the main doping solution &quot;

Methylene chloride 340 parts by mass

ethanol 64 parts by mass

Cellulose acetate propionate (acetyl group substitution degree: 1.50, propionyl group substitution degree: 0.90, total substitution degree: 2.40) 100 parts by mass

Ester ester compound 5.0 parts by mass

Ester compound 5.0 parts by mass

Ultraviolet absorber 1.5 parts by mass

Particle addition liquid 1 1 part by mass

&Lt; Synthesis of sugar ester compound &

A sugar ester compound was synthesized by the following process.

34.2 g (0.1 mol) of sucrose, 180.8 g (0.6 mol) of anhydrous benzoic acid, and 379.7 g (4.8 mol) of pyridine were fed into 4-necked colbins equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introducing tube, The temperature was elevated while nitrogen gas was bubbled through the nitrogen gas introduction tube, and the esterification reaction was carried out at 70 DEG C for 5 hours.

Subsequently, the internal pressure of collven was reduced to 4 × 10 ² Pa or less, excess pyridine was distilled off at 60 ° C., the pressure in collven was reduced to 1.3 × 10 4 Pa or lower, and the temperature was raised to 120 ° C. to obtain an anhydrous benzoic acid Most were distilled off.

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

The obtained mixture was analyzed by HPLC and LC-MASS to find that 1.3 mass% of A-1, 13.4 mass% of A-2, 13.1 mass% of A-3, 31.7 mass% of A- Mass%. The average degree of substitution was 5.5.

&Quot; Measurement conditions of HPLC-MS &

1) LC section

(JASCO CO-965), a detector (JASCO UV-970-240nm), a pump (JASCO PU-980), a condenser (JASCO DG-980-50)

Column: Inertsil ODS-3 Particle diameter 5 占 퐉 4.6 占 250 mm (manufactured by GEI Scientific Co., Ltd.)

Column temperature: 40 DEG C

Flow rate: 1 ml / min

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

Injection volume: 3μl

2) MS Department

Apparatus: LCQ DECA (manufactured by Thermo Quest Co., Ltd.)

Ionization method: Electrospray ionization (ESI) method

Spray Voltage: 5kV

Capillary temperature: 180 ° C

Vaporizer temperature: 450 ° C

&Lt; Synthesis of ester compound &

An ester compound was synthesized by the following steps.

(251 g), phthalic anhydride (278 g), adipic acid (91 g), benzoic acid (610 g) and tetraisopropyl titanate (0.191 g) as an esterification catalyst were placed in a thermometer, a stirrer, The flask was charged into a 2 L four-necked flask, and the temperature was gradually raised while stirring in a nitrogen stream until the temperature became 230 ° C. After dehydration condensation reaction for 15 hours, unreacted 1,2-propylene glycol was removed by distillation under reduced pressure at 200 DEG C after completion of the reaction to obtain an ester compound. The ester compound has an ester of benzoic acid at the end of the polyester chain formed by condensing 1,2-propylene glycol, phthalic anhydride and adipic acid. The acid value of the ester compound was 0.10, and the number average molecular weight was 450.

An endless belt flexing device was then used and was uniformly flexible on the stainless steel belt support.

In the endless belt flexing apparatus, the main dope liquid was uniformly softened on the stainless steel belt support. On the stainless steel belt support, the solvent was evaporated until the amount of the residual solvent in the long film (cast) was 75%, peeled off on the stainless steel belt support, and dried while conveying in a plurality of rolls, Film 1 was obtained.

(Long film 2)

The long film 2 is a cycloolefin resin film (COP), and was produced by the following production method.

1.2 parts by mass of 1-hexene, 0.15 parts by mass of dibutyl ether and 0.30 parts by mass of triisobutylaluminum were put into a reactor at room temperature and mixed in 500 parts by mass of dehydrated cyclohexane in a nitrogen atmosphere. 20 parts by mass of cyclo [4.3.0.12,5] dec-3,7-diene (dicyclopentadiene, hereinafter abbreviated as DCP), 1,4-methano-1,4,4a, 9a-tetrahydrofluorene 140 parts by mass of a norbornene-based monomer mixture (hereinafter abbreviated as MTF) and 40 parts by mass of 8-methyl-tetracyclo [4.4.0.12,5.17,10] -dodeca-3-ene And 40 parts by mass of tungsten hexachloride (0.7% toluene solution) were continuously added over 2 hours to polymerize. 1.06 parts by mass of butyl glycidyl ether and 0.52 parts by mass of isopropyl alcohol were added to the polymerization solution to inactivate the polymerization catalyst to terminate the polymerization reaction.

Subsequently, 270 parts by mass of cyclohexane was added to 100 parts by mass of the reaction solution containing the obtained ring-opening polymer, and 5 parts by mass of a nickel-alumina catalyst (manufactured by Nikkaki Catalysts Co., Ltd.) was added as a hydrogenation catalyst. , The mixture was heated to 200 DEG C while stirring and then reacted for 4 hours to obtain a reaction solution containing 20% of DCP / MTF / MTD ring opening polymerized hydrogenated polymer.

After the hydrogenation catalyst was removed by filtration, a soft polymer (Kurelase; Septon 2002) and an antioxidant (Irganox (1010), manufactured by Ciba Specialty Chemicals, Inc.) were added and dissolved in the obtained solution 0.1 part by mass per 100 parts by mass of the polymer). Subsequently, cyclohexane and other volatile components as a solvent were removed from the solution by using a cylindrical condenser dryer (Hitachi Seisakusho Co., Ltd.), and the hydrogenated polymer was extruded from the extruder into a strand in a molten state, And then recovered by pelletizing. The copolymerization ratio of the respective norbornene monomers in the polymer was calculated by the composition of residual norbornenes in the solution after the polymerization (by gas chromatography). The DCP / MTF / MTD = 10/70 / Respectively. The ring opening polymer hydrogenation product had a weight average molecular weight (Mw) of (31,000, a molecular weight distribution (Mw / Mn) of 2.5, a hydrogenation rate of 99.9%, and a Tg of 134 占 폚.

The resulting pellets of the ring opening polymerized hydrogenation product were dried at 70 DEG C for 2 hours using a hot-air drier through which air was circulated to remove water. Subsequently, the pellets were melt-extruded using a single-screw extruder having a T-die of a coat hanger type (manufactured by Mitsubishi Kogyo K.K., screw diameter 90 mm, T-die lip portion material: tungsten carbide, peel strength with molten resin 44 N) Followed by molding to produce a cycloolefin polymer film. In the extrusion molding, a long film 2 having a width of 1500 mm was obtained in a clean room of class 10,000 or less under the molding conditions of a molten resin temperature of 240 캜 and a T-die temperature of 240 캜.

[Production of warp stretched film]

Using the long film 1 containing the cellulose-based resin prepared above, oblique stretching was carried out in the following manner. That is, the long film 1 (fabric film) of the cellulose resin obtained above was stretched under the stretching conditions (number of conveying direction temperature regions, temperature history, temperature difference, number of temperature region in the width direction, conveying speed, The stretched portion 5 was subjected to oblique stretching to obtain a long warped stretched film (Examples 1 to 10, 12 to 16, and Comparative Examples 1 to 2, 4 to 8 in Table 1). At this time, the temperature of the preheating zone Z1 of the stretching section 5 was set to 200 deg. C, the temperature of the stretching zone Z2 to 200 deg. C, the temperature of the heat fixing zone Z3 to 170 deg. The final film width after application was 1300 mm.

In addition, for the raw material film (long film 2) containing COP, oblique stretching was performed in the same manner as described above. First of all, both ends of the unstretched film A (long film 2) sent from the film feeding portion 2 in the vicinity of the front of the heating zone Z are connected to the first clip as the leading waveguide Ci, And held by a second clip as a wave earth Co on the delay side. Further, when gripping the unstretched film A, the clip lever of the first and second clips is moved by the clip closure to grip the unstretched film A. At the time of clip gripping, both ends of the unstretched film A are grasped by the first and second clips at the same time, and grasped so that the lines connecting the grasping positions at both ends with respect to the axis parallel to the film width direction are parallel .

Subsequently, oblique stretching was performed in the stretching section 5 under the conditions shown in Table 1 to obtain a long warped stretched film (see Example 11 and Comparative Example 3 in Table 1). That is, the untreated film A held by the holding means is gripped and held by the first and second clips while being conveyed while passing through the preheating zone Z1, stretching zone Z2 and heat fixing zone Z3 in the heating zone Z To obtain a stretched film A 'which was stretched in the oblique direction with respect to the width direction.

The film moving speed at the time of heating and stretching was 15 m / min. The temperature of the preheating zone Z1 was 147 占 폚, the temperature of the stretching zone Z2 was 147 占 폚, and the temperature of the heat-fixing zone Z3 was 140 占 폚. The stretching magnification of the film before and after stretching was 1.3 times, and the film thickness after stretching was 50 占 퐉.

The temperature described in each of the above embodiments is the temperature of the zone, not the film temperature.

[About stretching conditions]

Here, the description of the stretching condition is supplemented. The transport direction temperature region number indicates the number of temperature regions in the transport direction in the oblique stretching region. In addition, when the number of temperature zones in the transport direction is 1, the temperature zone is not divided into two or more in the transport direction, and the film temperature is not changed in the transport direction.

The temperature history refers to any pattern (temperature profile) of the temperature distribution in the carrying direction shown in Figs. Pattern 1 is a profile having no temperature change in the carrying direction. Patterns 2-1 to 2-3 indicate profiles in which the temperature changes in two stages in the transport direction. The pattern 2-1 indicates a profile at which the temperature at the end of bending is higher than the bending start time, and the patterns 2-2 and 2-3 indicate the profile at which the temperature at the end of bending is lower than the bending start time . Particularly, pattern 2-3 indicates the temperature profile in the carrying direction with respect to the delay side in the width direction, and the temperature at the start of the bending is lower than the temperature at the leading side.

The pattern 2-1 can be realized, for example, by reversing the arrangement of the heating units 11 and 12 in FIG. 5 (the temperature at the time of termination can be made higher than at the time of starting the bending). The pattern 2-2 can be realized by the arrangement of the heating units 11 and 12 shown in Fig. 5, for example. The pattern 2-3 can be realized, for example, by reversing the arrangement of the heating units 11 and 21 in FIG. 7 (the temperature on the delay side can be made lower than that on the preceding side at the start of bending).

Patterns 3-1 and 3-2 indicate profiles in which the temperature changes in three stages in the carrying direction, all of which are profiles in which the temperature at the end of bending is lower than the bending starting point. Particularly, the pattern 3-2 indicates the temperature profile in the conveying direction with respect to the delay side in the width direction, and the temperature at the start of the bending is lower than the temperature at the leading side.

The pattern 3-1 can be realized, for example, by arranging the three heating portions 11 to 13 in parallel in the conveying direction from the upstream side to the downstream side in the warp stretching region in the same manner as in Fig. However, the output of the heating unit is the heating unit 11> the heating unit 12> the heating unit 13. The pattern 3-2 can be realized, for example, by reversing the arrangement of the heating units 11, 21 and arranging the heating unit 13 at the most downstream side of the oblique stretching region in Fig.

The installation conditions are as follows. Whether or not the heating portion is arranged so that the gap portion between the heating portions adjacent to each other in the width direction becomes staggered (in a state deviating from the conveying path) in the conveying direction, the joint between the hot air- Whether or not a heating section is arranged so as to be in a zigzag pattern (a state deviating from a conveying locus), and whether or not a facility section (including a rail position adjusting section and a heating section) is disposed so as to be symmetrical with respect to a direction along the carrying direction before warp- And whether or not the exhaust is performed so that the temperature distribution in the exhaust gas is uniform.

The temperature difference is a value obtained by subtracting the temperature T2 (占 폚) of the film at the end of bending from the temperature T1 (占 폚) of the film at the beginning of bending in the oblique stretching region. As for the film temperature T1 占 T2, the temperature of the ejection port for ejecting the hot air of the nozzle constituting the heating section was used as the film temperature. When a plurality of temperature regions are formed in the width direction, the difference between the temperature T1 of the film and the film temperature T2 at the most upstream side is determined as the temperature difference.

The number of the width direction temperature regions indicates the number of temperature regions in the width direction in the warp stretching region. The number corresponds to the case where the number of the widthwise temperature regions is 1, the temperature region is not divided into two or more in the width direction, and the film temperature is not changed in the width direction. In Table 1, when there are two or more regions having different temperatures in the width direction in the oblique stretching region, the location of these regions (which position in the transport direction) is shown together.

The number of temperature regions in the width direction was determined by arranging four heating portions side by side in the width direction and adjusting the heating temperature of each heating portion. Therefore, for example, of the four heating portions arranged in the width direction, the heating temperatures of the two heating portions on the preceding side are made the same, and the heating temperatures of the two heating portions on the delay side are made the same, The number of temperature zones in the width direction can be set to two by changing the heating temperatures of the respective groups.

[Production of circularly polarizing plates 1 to 16]

Using the long oblique stretched film under oblique stretching under the same conditions as above, circular polarizers 1 to 16 were produced as follows.

That is, a polyvinyl alcohol film having a thickness of 120 탆 was uniaxially stretched (at a temperature of 110 캜, a stretching magnification of 5 times), immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, 6 g of potassium, 7.5 g of boric acid, and 100 g of water. The film after immersion was washed with water and dried to obtain a polarizer.

Subsequently, the long oblique stretched films of Examples 1 to 16 produced were bonded to one surface of the polarizer using a 5% aqueous solution of polyvinyl alcohol as a pressure-sensitive adhesive. At this time, the transmission axis of the polarizer and the slow axis of the warp stretched film were bonded so as to be in a direction of 45 degrees. Then, the other side of the polarizer was similarly joined with an alkali saponified Konica Minolta Tact Film KC4UAH (manufactured by Konica Minolta Co.) to produce circularly polarizing plates 1 to 16.

[Production of circularly polarizing plates 17 to 32]

Using the long oblique stretched film under oblique stretching under the same conditions as above, circular polarizers 17 to 32 were produced as follows.

That is, a polyvinyl alcohol film having a thickness of 120 탆 was uniaxially stretched (at a temperature of 110 캜, a stretching magnification of 5 times), immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, 6 g of potassium, 7.5 g of boric acid, and 100 g of water. The film after immersion was washed with water and dried to obtain a polarizer.

Subsequently, the long oblique stretched films of Examples 1 to 16 produced were bonded to one surface of the polarizer using a 5% aqueous solution of polyvinyl alcohol as a pressure-sensitive adhesive. At this time, the transmission axis of the polarizer and the slow axis of the warp stretched film were bonded so as to be in a direction of 45 degrees. Then, the other side of the polarizer was similarly joined with an alkali saponified Konica Minolta Tact Film KC2CT1 (manufactured by Konica Minolta Co.) to produce circularly polarizing plates 17 to 32.

[Production of organic EL display devices 1 to 16]

A reflective electrode containing chromium of 80 nm in thickness was formed on the glass substrate by the sputtering method. Subsequently, ITO (indium tin oxide) was formed as a positive electrode on the reflective electrode by a sputtering method to a thickness of 40 nm. Then, poly (3,4-ethylenedioxythiophene) -polystyrenesulfonate (PEDOT: PSS) was formed as a hole transporting layer on the anode at a thickness of 80 nm by sputtering. Thereafter, each of the R, G, and B emission layers was formed to have a thickness of 100 nm by using a shadow mask on the hole transport layer.

Further, calcium was deposited as a first cathode having a low work function capable of efficiently injecting electrons onto the light emitting layer to a thickness of 4 nm by a vacuum deposition method. Thereafter, aluminum was formed to a thickness of 2 nm as a second negative electrode on the first negative electrode. The aluminum used as the second cathode has a role of preventing the calcium serving as the first anode from chemically altering when forming the transparent electrode formed thereon by the sputtering method. Thus, an organic light emitting layer was obtained.

Subsequently, a transparent conductive film was formed to a thickness of 80 nm on the cathode by a sputtering method. ITO was used as the transparent conductive film. Further, silicon nitride was formed to a thickness of 200 nm on the transparent conductive film by a CVD method (chemical vapor deposition method) to form an insulating film. Thus, an organic EL device was fabricated. The size of the fabricated organic EL device was 1296 mm x 784 mm.

On the insulating film of the prepared organic EL device, circular polarizers 1 to 15 prepared as described above are fixed with an adhesive so that the surface of the obliquely drawn film faces the surface of the insulating film of the organic EL device. Thus, the organic EL display devices 1 to 16 were produced.

[Production of liquid crystal display devices 1 to 16]

&Quot; Fabrication of liquid crystal display device &quot;

The polarizers on the viewing side of the commercially available 10-inch liquid crystal display device were peeled off and the circular polarizers 17 to 32 were adhered with a pressure sensitive adhesive so that the surfaces of the Konica Minolta tact film KC2CT1 faced the surface of the liquid crystal cell To thereby produce liquid crystal display devices 1 to 16. The circular polarizers 17 to 32 were bonded so that the polarizer absorption axes of the circular polarizers 17 to 32 were oriented in the same direction as the polarizer absorption axis of the polarizer previously bonded.

〔evaluation〕

(Evaluation of fluctuation of in-plane retardation Ro in the width direction)

In order to investigate the fluctuation of the in-plane retardation Ro in the width direction of the produced film, from the obliquely drawn films produced by the same methods as in Examples 1 to 16 and Comparative Examples 1 to 8 in Table 1, 40 samples were cut out and the in-plane retardation Ro (nm) was measured using an automatic birefringence measuring device (KOBRA-21ADH manufactured by Oji Keisoku Kikai K.K.). Then, the measurement in the width direction was performed three times in the conveying direction, and the average value in the conveying direction was calculated with respect to all data of the in-plane retardation Ro in the width direction. The difference between the maximum value and the minimum value in the width direction of the calculated value (average value of the in-plane retardation Ro in the conveying direction) is regarded as a variation of the in-plane retardation Ro in the width direction, Respectively.

"Evaluation standard"

A: The fluctuation of the in-plane retardation Ro is less than 1.0 nm.

B: Variation of the in-plane retardation Ro is 1.0 nm or more and less than 1.5 nm.

C: The variation of the in-plane retardation Ro is 1.5 nm or more and less than 2.0 nm.

D: Variation of the in-plane retardation Ro is 2.0 nm or more and less than 3.0 nm.

E: Variation of in-plane retardation Ro is 3.0 nm or more.

(Evaluation of Unevenness of Reflected Light Quantity)

The above-described organic EL image display apparatus was fabricated for each example and each comparative example, and the difference in color sensitivity (color unevenness) for each display was displayed in black under sunlight, Respectively. That is, the unevenness of the reflected light quantity was visually observed, and the unevenness of reflected light quantity (color unevenness) was evaluated based on the following evaluation criteria.

"Evaluation standard"

A: In all of the manufactured organic EL image display devices, there is no person who feels a difference in reflected light quantity for each place and device.

B: In all the manufactured organic EL image display apparatuses, the ratio of people who feel the difference in reflected light quantity for each place and apparatus is 10% or less.

C: In all manufactured organic EL image display apparatuses, the ratio of people who feel a difference in reflected light quantity for each place / apparatus is more than 10% and not more than 20%.

D: In all of the manufactured organic EL image display apparatuses, the ratio of people who feel a difference in reflected light quantity at each spot: device is more than 20% and not more than 50%.

E: In all of the produced organic EL image display apparatus, the ratio of people who feel the difference in the amount of reflected light at each place and place is more than 50%.

Table 1 shows the results of evaluating the non-uniformity of the in-plane retardation Ro in the width direction and the unevenness of the reflected light quantity in the warp stretched films of Examples 1 to 16 and Comparative Examples 1 to 8. The temperature difference in Table 1 is a value measured using the above-mentioned heat-resistant type noncontact temperature sensor (IRtec Rayomatic 14, manufactured by Eurotron Co., Ltd.). The temperature difference is a temperature difference of the film measured by the above method, and is not the temperature difference of each zone of the stretching portion.

It can be seen from the results of Examples 1 to 16 and Comparative Examples 1 and 3 to 4 that the film temperature is lowered at the end of the drawing (at the end of bending) than at the start of drawing (at the beginning of bending) in the oblique drawing region, (In Table 1, the evaluation of the unevenness of the reflected light quantity becomes C or more).

From the results of Examples 1 to 16 and Comparative Example 2, even when the film temperature is changed stepwise in the transport direction in the warp stretching region, if the temperature of the film at the end of bending is higher than that at the time of bending, It can be said that it is necessary to lower the temperature of the film at the time of the bending end to be lower than that at the start of bending.

From the results of Examples 1 and 2, it was found that when the film temperature is further changed in the widthwise direction in the obliquely stretched region, the non-uniformity of the in-plane retardation Ro in the width direction is reduced ), It is more preferable to perform temperature control in the width direction in addition to the transport direction.

From the results of Examples 1 and 3, it was found that, in the oblique stretching region, when the temperature of the film at the end of bending is lower than 2 占 폚 from that at the time of bending start, unevenness of the reflected light quantity can be further reduced, It is more preferable to give a temperature difference of 2 DEG C or more.

From the results of Examples 1 and 4, it was found that when the film temperature was lowered in three stages in the transport direction in the oblique stretching region, the unevenness of the reflected light quantity could be further reduced as compared with the case where the film temperature was lowered in two stages, It may be said that it is desirable to increase the number of steps of the temperature change in the direction.

It is also understood from the results of Examples 4 and 5 that it is preferable to change the film temperature in the widthwise direction both when the film temperature is lowered in three stages in the transport direction in the warp stretching region, It can be said that the unevenness of Ro can be further reduced.

From the results of Example 6 and Examples 7 and 8, if the gaps of the heating portions adjacent to each other in the width direction or the joints of adjacent hot air blowing outlets are located in a zigzag manner in the carrying direction, The in-plane retardation Ro in the width direction is reduced, so that it is preferable to arrange the heating portion in which the gap portion or the joint becomes a zigzag shape.

In the ninth embodiment, asymmetrical pseudo equipment is provided so that the equipments of the inclined stretching units of the seventh and eighth examples are symmetrical in the width direction, and oblique drawing is performed. In this case, The in-plane retardation Ro of the photocatalyst film is further reduced, it is preferable to perform the oblique stretching by providing such a physician facility.

The tenth embodiment is an example in which oblique stretching is performed by making the temperature distribution in the furnace of the inclined stretching sections of Examples 7 and 8 uniform in the width direction by making the evacuation capability on the preceding side stronger than the retarding side. Plane retardation Ro in the width direction is further reduced, it is preferable to perform oblique stretching while performing such exhausting.

From the results of Example 5 and Example 11, it can be seen that the effect of reducing the unevenness of the reflected light quantity by the oblique stretching method of the present embodiment is obtained regardless of the material used for the film (whether it is a cellulose resin or a COP resin) have.

From the results of Examples 5 and 12, even when the obliquely stretched film is produced by increasing the conveying speed of the film, the in-plane retardation Ro unevenness in the width direction and the reflected light amount It can be understood that the effect of reducing unevenness is obtained.

Also, as in Examples 13 to 16, even in the case of producing an obliquely-elongated film by raising the draw ratio to 1.4 or more, the in-plane retardation Ro unevenness in the width direction and the unevenness of the reflected light amount unevenness A reduction effect can be obtained.

It is also understood that, as in Examples 13 and 15, even when the film is transported at a speed of 5 m / min to obliquely stretch the film, the effect of reducing the amount of reflected light is obtained. Further, when the stretching magnification is high, the amount of shrinkage at the end of bending becomes large. Therefore, the film tends to vibrate at the time of oblique stretching and the optical value tends to vary. From the results of Examples 13 and 15, however, It can be seen that by controlling the temperature in the stretching region, the vibration of the film at the time of oblique stretching is suppressed, and the unevenness of the optical value is reduced, whereby the unevenness of the reflected light quantity can be reduced.

Furthermore, in the liquid crystal display devices 1 to 16 produced by using the obliquely drawn films produced in Examples 1 to 16 and using the circularly polarizing plates 17 to 32, the black screen was displayed, It was confirmed that even when the polarized sunglasses were attached and the display screen was visually observed, the screen was uniformly displayed in black, and the color unevenness due to the unevenness of the reflected light quantity was not observed.

The above-described method of producing the warp stretched film of this embodiment can be expressed as follows.

1. The film is gripped at both ends in the width direction of the film by a pair of gripping pawls to relatively advance the one waveguide and relatively delay the other waveguide to transport the film, And a warp stretching step of stretching the film in an oblique direction with respect to a width direction by bending the film in a warp direction,

Wherein in the warp stretching step, the temperature of the film at the end of bending of the arc on the conveying path for stretching in the oblique direction is made lower than the starting point of the bending.

2. When the temperature of the film at the start of bending is T1 (占 폚) and the temperature of the film at the end of bending is T2 (占 폚)

(T1-T2) &gt; 2 [deg.] C

(1). &Lt; / RTI &gt;

3. The method of producing an oblique-drawn film according to 1 or 2, wherein the temperature of the film is changed stepwise or continuously in the conveying direction in the section from the start to the end of the bending.

4. The method of producing an obliquely-drawn film as described in 3 above, wherein the temperature of the film is changed in three or more stages in the transport direction in the section.

5. The method of producing an obliquely-drawn film according to any one of 1 to 4, wherein the temperature of the film is changed in the width direction from the start to the end of the bending.

6. The film according to any one of claims 1 to 5, wherein the film is heated or cooled such that the temperature of the film at the end of the bending is lower than the start time of the bending in the section from the start to the end of bending Wherein the warp stretched film is produced by a method comprising the steps of:

7. The film is heated using a heating section having at least one heating zone,

Wherein the heating region is located in both the width direction and the transport direction of the film and the unheated region between the two heating regions adjacent in the width direction is connected from the upstream side to the downstream side in the transport direction Wherein the imaginary line drawn by the imaginary line is shifted from the transporting trajectory of an arbitrary point of the film.

8. The method of producing an obliquely-drawn film according to 7 above, wherein the unheated region includes a gap portion between two heating regions adjacent in the width direction.

9. The method of producing an obliquely-drawn film as described in 7 or 8 above, wherein the unheated area includes a joint between hot air blowing outlets as two heating zones adjacent in the width direction.

10. The apparatus according to any one of claims 1 to 10, wherein the equipment section including an adjustment section for adjusting the position of a rail on which the pair of waveguides travels is disposed symmetrically with respect to a direction along the transport direction before the film is obliquely stretched, The method of producing an obliquely-drawn film according to any one of 1 to 9 above, wherein the oblique stretching is performed.

11. The temperature distribution in the transverse direction of the film during the conveyance of the film in the entire section from the start to the end of the bending in the furnace subjected to the oblique stretching process is set so that the temperature- The method of manufacturing an oblique drawn film according to any one of 1 to 10 above, wherein the inside of the furnace is evacuated so as to be symmetrical with respect to the center between the rails of the preceding side in the delay side and the preceding side.

12. The method of producing an obliquely-drawn film according to any one of 1 to 11 above, wherein the film comprises a cellulose-based resin.

13. The method of producing an obliquely-drawn film as described in any one of 1 to 12 above, wherein the stretching ratio of the film obliquely stretched in the section from the start to the end of the bending is 1.4 to 2.3 times.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, in the production of a circularly polarizing plate for preventing reflection of external light of an organic EL image display apparatus.

Ci: Pe district
Co: Far East
11:
11a: heating zone
12:
12a: heating zone
13:
13a: heating zone
21:
Bo: joint (unheated area)
Ri: Rail
Ro: Rail
H: Spout (heating area, hot air spout)
M:
S: gap part (unheated area)
V: virtual line
Y: Equipment department

Claims (13)

Both ends of the film in the width direction are gripped by a pair of gripping portions, the one waveguide segment is relatively advanced, the other waveguide segment is delayed relatively, and the film is transported, And a warp stretching step of stretching the film in an oblique direction with respect to the width direction by bending the film,
Wherein in the warp stretching step, the temperature of the film at the end of bending of the arc on the conveying path for stretching in the oblique direction is made lower than the starting point of the bending. The method according to claim 1, wherein when the temperature of the film at the start of bending is T1 (占 폚) and the temperature of the film at the end of bending is T2 (占 폚)
(T1-T2) &gt; 2 [deg.] C
Wherein the film has a thickness of 100 mu m or less. The method of manufacturing an oblique drawn film according to claim 1 or 2, wherein the temperature of the film is changed stepwise or continuously in the transport direction in the section from the start to the end of the bending. The method of manufacturing an oblique drawn film according to claim 3, wherein the temperature of the film is changed in three or more stages in the conveying direction in the section. The method of manufacturing an oblique drawn film according to any one of claims 1 to 4, wherein the temperature of the film is changed in the width direction from the start to the end of the bending. The method according to any one of claims 1 to 5, further comprising heating the film so that the temperature of the film at the end of the bending is lower than the start time of the bending in the section from the start to the end of bending Or cooling the film. 7. The method according to claim 6, wherein the film is heated using a heating portion having at least one heating region,
Wherein the heating region is located in both the width direction and the transport direction of the film and the unheated region between the two heating regions adjacent in the width direction is connected from the upstream side to the downstream side in the transport direction Wherein the imaginary line is shifted from a transporting trajectory of an arbitrary point of the film. The method of producing an obliquely-drawn film according to claim 7, wherein the unheated region includes a gap portion between two heating regions adjacent in the width direction. The method of producing an obliquely-drawn film according to claim 7 or 8, wherein the unheated area includes a joint between the hot air blowing outlets as two heating zones adjacent in the width direction. 10. The film forming apparatus according to any one of claims 1 to 9, wherein the equipment part including an adjustment part for adjusting the position of a rail on which the pair of waveguides travels is disposed in a direction along the transport direction before the oblique stretching of the film Wherein the warp stretching film is arranged so as to be symmetrical on the delay side and the preceding side, and subjected to oblique stretching. 11. The method according to any one of claims 1 to 10, wherein the temperature distribution in the width direction during transport of the film in the entire section from the start to the end of the bending, Wherein the inside of the furnace is evacuated so that the furnace is symmetrical with respect to the center between the rail on the delay side on which the pair of wave earth travels and the rail on the leading side. The method of producing an obliquely-drawn film according to any one of claims 1 to 11, wherein the film comprises a cellulose-based resin. The method of producing an obliquely-drawn film according to any one of claims 1 to 12, wherein the stretching magnification of the film obliquely stretched in the section from the start to the end of the bending is 1.4 to 2.3 times.

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