JP2012088592A - METHOD FOR PRODUCING LONG-SIZED POLYMER FILM, λ/4 PLATE, POLARIZING PLATE, AND STEREOSCOPIC IMAGE DISPLAY DEVICE - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a long-sized polymer film applicable as a λ/4 plate, where crosstalk does not occur even when a viewer inclines his or her neck while viewing a stereoscopic image on a display with spectroscopic image viewing spectacles on, and to provide a λ/4 produced by this method, and a polarizing plate and a stereoscopic image display device which include the λ/4 plate.SOLUTION: In the method for producing a long-sized polymer film, a rear end part of a preceding polymer film is coincided with a front end part of a succeeding polymer film to join them together, and the polymer films are continuously drawn in an oblique direction forming an angle of 40 to 50° with a breadthwise direction of the polymer film. The rear end part of the preceding polymer film and the front end part of the succeeding polymer film are joined together so that a junction line in a junction between them is substantially parallel (at an angle of -10 to 10°) with the breadthwise direction after oblique drawing.

Description

  The present invention relates to a method for producing a long polymer film, a λ / 4 plate produced by the production method, a polarizing plate provided with the λ / 4 plate, and a stereoscopic image display device.

  In recent years, stereoscopic image display devices such as televisions capable of displaying stereoscopic (3D) images have been proposed. As one of the methods for displaying the stereoscopic image, there is a method for allowing the observer to recognize the two-dimensional image as a stereoscopic image by wearing dedicated stereoscopic image viewing glasses by the observer. What is currently viewed as promising in this method is that the right-eye image and the left-eye image, which are parallax images, are alternately displayed in time series on the display that displays the image, and the observer uses glasses for viewing stereoscopic images. This is a method in which an image of a display is viewed while wearing (see, for example, Patent Document 1).

  The stereoscopic image display device including the display and the glasses for visually recognizing stereoscopic images has problems such as crosstalk (a phenomenon that appears double), a decrease in luminance, and a change in color when the head is tilted. In order to prevent the occurrence of such a problem when the head is tilted, it is effective to use λ / 4 plates on the surface on the viewing side of the liquid crystal display and the surface on the side far from the eyes of the stereoscopic image viewing glasses. .

  In the case of producing such a polymer film functioning as a λ / 4 plate, when a polarizer stretched in the longitudinal direction and the λ / 4 plate are bonded together in a roll-to-roll manner in the subsequent polarizing plate forming step, λ / 4 It is necessary to stretch the plate in an oblique direction (hereinafter referred to as “oblique stretching”). When this oblique stretching is performed, it may not be appropriate to set the stretching speed to be the same as the film forming speed in order to produce a film with better mechanical strength and flatness. For this reason, it is desirable to extend | stretch by the extending line different from a film forming line (henceforth "offline extending | stretching") (for example, refer patent document 2).

  As described in Patent Document 2, in order to efficiently perform off-line stretching, it is preferable to stretch the film continuously. Therefore, when performing off-line stretching for one film roll, it is necessary to join the leading edge of the subsequent film fed from the film roll to the trailing edge of the preceding film fed from the one film roll. is there.

  As a joining method in such a case, conventionally, a method using a double-sided tape, a solvent, thermal welding, or the like is known (for example, see Patent Documents 3 to 6).

  However, it has been found that the conventional joining method is applicable to stretching in the width (TD) direction but not to oblique stretching. That is, when a polymer film bonded and obliquely stretched using a conventional bonding method is used for the stereoscopic image display device and stereoscopic image viewing glasses, crosstalk is likely to occur when the neck is tilted. It became clear by examination of this inventor.

  As a result of further investigation to investigate the cause, this crosstalk is caused by the in-plane orientation angle disorder of the polymer film, and the in-plane orientation angle disorder is caused by partial peeling of the joint portion. Turned out to be.

  That is, when the film is obliquely stretched in a state where the rear end portion or the front end portion of the film is joined so as to be substantially parallel to the width direction as in the prior art, the joining portion where the films overlap is larger in the oblique direction. Elongation occurs. In addition, since the film thickness is increased at the joint portion where the films overlap, the stretching stress and the shrinkage stress acting in the direction orthogonal to the stretching work more strongly than the other portions. Therefore, it is difficult to orient the film uniformly with the extension of the joint part, and the strong stress due to the joint part inevitably causes distortion around the joint part, resulting in failures such as partial peeling and orientation angle disorder. It is thought that it will end.

Japanese Patent Laid-Open No. 8-201942 JP 2002-311240 A JP 2008-238678 A JP 2009-160914 A JP 2009-226915 A JP 2009-90651 A

  The present invention has been made in view of the above problems and situations, and the solution is to cross-talk even when the viewer tilts his / her head when viewing the stereoscopic image of the display while wearing stereoscopic image viewing glasses. It is providing the manufacturing method of the elongate polymer film applicable as a (lambda) / 4 board which does not generate | occur | produce, and the (lambda) / 4 board manufactured by the said manufacturing method. Another object of the present invention is to provide a polarizing plate and a stereoscopic image display device provided with the λ / 4 plate.

  In order to solve the above-mentioned problems, the inventors of the present invention have made the present invention as a result of intensive studies from the viewpoint of suppressing a strong stress caused by a joint portion generated during stretching.

  That is, the said subject which concerns on this invention is solved by the following means.

  1. (1) a joining step of superimposing and joining a leading end portion of a succeeding polymer film on a trailing end portion of a preceding polymer film, and (2) while continuously transporting the joined polymer film, the polymer A stretching process in which the film is heated and both ends are supported by a plurality of gripping tools and stretched in an oblique direction at an angle that is in the range of 40 to 50 ° with the width direction of the polymer film; 3) A method for producing a long polymer film comprising a thermal relaxation step of performing heat treatment for stress relaxation while continuously transporting the stretched polymer film, the rear end of the preceding polymer film And the joining line at the joining portion with the leading edge of the film to be followed is joined so as to be substantially parallel (−10 to 10 °) with respect to the width direction after oblique stretching. A method for producing a long polymer film.

  2. The angle formed by the joining line at the joining portion of the leading end portion of the preceding polymer film and the leading end portion of the following polymer film and the film width direction is within a range of −70 to −20 ° before stretching. The manufacturing method of the elongate polymer film of said 1st term | claim characterized by the above-mentioned.

  3. 3. The long shape according to claim 1 or 2, wherein the leading end portion of the preceding polymer film and the leading end portion of the following polymer film are joined by welding using ultrasonic vibration. A method for producing a polymer film.

  4). A λ / 4 plate produced by the method for producing a long polymer film according to any one of Items 1 to 3, measured at a wavelength of 550 nm under an environment of 23 ° C. and 55% RH. The λ / 4 plate, wherein the in-plane retardation value Ro (550) is in the range of 110 to 170 nm.

  5. 6. A polarizing plate comprising the λ / 4 plate according to the fourth item.

  6). A stereoscopic image display apparatus comprising the λ / 4 plate according to the fourth aspect.

  With the above-described means of the present invention, when wearing stereoscopic image viewing glasses and viewing a stereoscopic image on a display, a long shape applicable as a λ / 4 plate that does not generate crosstalk even if the viewer tilts his / her neck A method for producing a polymer film and a λ / 4 plate produced by the production method can be provided. In addition, a polarizing plate and a stereoscopic image display device provided with the λ / 4 plate can be provided.

Conceptual diagram of an example of offline stretching equipment Conceptual diagram showing the shape of the joint before and after stretching the film Conceptual diagram showing an example of an oblique stretching machine in the tenter section Schematic diagram of a 3D image display device with a single polarizing plate for glasses Schematic diagram of a stereoscopic video display device with two polarizing plates for glasses Conceptual diagram of sample film for evaluation of in-plane orientation angle disorder

  The method for producing a long polymer film of the present invention includes (1) a joining step of superposing and joining a leading end portion of a succeeding polymer film on a trailing end portion of a preceding polymer film, and (2) joined. While continuously transporting the polymer film, the polymer film is heated, and both ends are supported by a plurality of gripping tools, and an angle between the width direction of the polymer film is within a range of 40 to 50 ° A stretching step of stretching in an oblique direction at an angle (referred to as "oblique stretching"), and (3) a thermal relaxation step of performing heat treatment for stress relaxation while continuously transporting the stretched polymer film. A method for producing a long polymer film, wherein a joining line at a joining portion between a rear end portion of the preceding polymer film and a leading end portion of the following film is a width after oblique stretching. Method of manufacturing an elongated polymer film, characterized by joining so as to be substantially parallel (-10 to 10 °) with respect to the direction. This feature is a technical feature common to the inventions according to claims 1 to 6.

  As an embodiment of the present invention, from the viewpoint of manifestation of the effects of the present invention, the joining line at the joining portion of the leading end of the preceding polymer film and the leading end of the following polymer film and the width direction of the film are formed The angle is preferably in the range of −70 to −20 ° before stretching. Furthermore, it is preferable that a rear end portion of the preceding polymer film and a front end portion of the succeeding polymer film are joined by welding using ultrasonic vibration.

  The λ / 4 plate produced by the method for producing a long polymer film of the present invention has an in-plane retardation value Ro (550) of 110 to 110 measured at a wavelength of 550 nm in an environment of 23 ° C. and 55% RH. It is preferably within the range of 170 nm. The λ / 4 plate can be suitably used for a polarizing plate and a stereoscopic image display device.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

(Outline of production method of long polymer film)
The method for producing a long polymer film of the present invention includes (1) a joining step of superposing and joining a leading end portion of a succeeding polymer film on a trailing end portion of a preceding polymer film, and (2) joined. While continuously transporting the polymer film, the polymer film is heated, and both ends are supported by a plurality of gripping tools, and an angle between the width direction of the polymer film is within a range of 40 to 50 ° A method of producing a long polymer film, comprising: a stretching step that obliquely stretches at an angle; and (3) a thermal relaxation step in which heat treatment for stress relaxation is performed while continuously transporting the stretched polymer film. The joining line at the joining portion between the rear end portion of the preceding polymer film and the leading end portion of the following film is substantially parallel to the width direction after oblique stretching (-10 to Wherein the bonding to be 0 °).

  In the present application, the “joining line of the joining portion” refers to a line (line) that forms the end of the trailing end of the preceding polymer film and a line (line) that forms the end of the leading end of the succeeding polymer film. Is a line (line) where both films are actually joined by tape or welding.

  As an embodiment of the present invention, from the viewpoint of manifestation of the effects of the present invention, the joining line at the joining portion of the leading end of the preceding polymer film and the leading end of the succeeding polymer film and the width direction of the film are formed. The angle is preferably in the range of −70 to −20 ° before stretching. Furthermore, it is preferable to join the rear end portion of the preceding polymer film and the front end portion of the subsequent polymer film by welding using ultrasonic vibration.

  The method for producing a long polymer film of the present invention is characterized in that it is stretched by a stretching line different from the solution casting film forming line (hereinafter referred to as “offline stretching”).

  Below, with reference to the whole figure (FIG. 1) of an example of the offline extending | stretching apparatus used for this offline extending | stretching, the outline | summary of the manufacturing method of the said elongate polymer film is demonstrated.

(Offline stretching device)
An offline stretching apparatus 1 shown in FIG. 1 stretches a polymer film, and includes a film supply unit 2, an accumulator unit (abbreviated as “accumulator unit”) 4, a tenter unit 5, an ear-cut device 6, The heat relaxation part 7, the cooling part 8, and the winding-up part 9 are provided, and these are arrange | positioned in order along the film conveyance direction c.

  The film supply unit 2 is provided with a film roll 11 manufactured by a film forming facility. The film roll 11 is a roll formed by winding a film around a core. A film is sent out from a film roll 11 provided in the film supply unit 2, and the film is stretched in an oblique direction while being heated by the tenter unit 5, and the temperature of the stretched film passes through the heat relaxation unit 7 and the cooling unit 8. It is lowered and taken up by the take-up unit 9. In the tenter part 5, the film is stretched 0.5 to 3 times in an oblique direction. The film supply unit 2, the tenter unit 5, the thermal relaxation unit 7, the cooling unit 8, and the winding unit 9 are provided with an EPC (edge position controller) that performs control to suppress the meandering of the film and accurately convey the film. ing. EPC is not shown.

<Film supply unit>
The film supply unit 2 includes a turret type film delivery device 13 and a bonding area 3. The film delivery apparatus 13 includes a turret arm 12 having attachment shafts 10 provided at both ends. A film roll 11 is attached to each mounting shaft 10. The turret arm 12 rotates 180 degrees to position one mounting shaft 10 at the delivery position (on the side of the joint 3) and the other mounting shaft 10 at the core replacement position. A film is sent out to the joining area 3 from the film roll 11 mounted on the mounting shaft 10 at the sending position. When all the films are sent out, the turret arm 12 rotates, the empty core is removed from the mounting shaft 10 located at the core replacement position, and a new film roll is mounted.

<Joint area>
In the joining area 3, in order to supply a continuous film to the tenter unit 5, the rear end portion of the preceding film sent out in advance is overlapped with the front end portion of the subsequent film sent out later. , Join. If necessary, unnecessary portions may be cut after joining.

<Accumulator>
An accumulator unit (abbreviated as “accumulator unit”) 4 is disposed between the film supply unit 2 and the tenter unit 5, and the accumulator unit 4 has a length equal to or longer than that required for the film bonding process. Form a film loop. For this reason, at the time of film joining, since the film stored in the accumulation part 4 is sent out to the tenter part 5, the joining process of a film can be performed without stopping the tenter part 5.

<Tenter section>
The tenter of the tenter unit 5 is an apparatus that widens a long film in an oblique direction with respect to its traveling direction (moving direction of the middle point in the film width direction) in an oven heating environment. The tenter includes an oven, a pair of rails on the left and right on which a gripping tool (eg, a clip) for transporting the film travels, and a number of gripping tools that travel on the rail. Both ends of the film fed out from the film roll and sequentially supplied to the entrance portion of the tenter are gripped by a gripping tool, the film is guided into the oven, and the film is released from the gripping tool at the exit portion of the tenter. The film released from the gripping tool is wound around the core. Each of the pair of rails has an endless continuous track, and the gripping tool which has released the grip of the film at the exit portion of the tenter travels outside and is sequentially returned to the entrance portion.

  The rail shape of the tenter is asymmetrical on the left and right according to the in-plane orientation angle, stretch ratio, etc. given to the polymer film to be manufactured, and can be finely adjusted manually or automatically. .

  In the present invention, a long thermoplastic polymer film is stretched so that the in-plane orientation angle can be set to an arbitrary angle within the range of 10 ° to 80 ° with respect to the winding direction after stretching. It has become. In the present invention, the gripping tool of the tenter is configured to travel at a constant speed with a certain distance from the front and rear gripping tools.

  The traveling speed of the gripping tool can be selected as appropriate, but is usually 10 to 100 m / min. The difference in travel speed between the pair of left and right grippers is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed. This is because if there is a difference in the traveling speed between the left and right sides of the film at the exit of the stretching process, wrinkles and shifts will occur at the exit of the stretching process, so the speed difference between the right and left gripping tools is required to be substantially the same speed. Because. In general tenter devices, etc., there are speed irregularities that occur on the order of seconds or less depending on the period of the sprocket teeth that drive the chain, the frequency of the drive motor, etc. This does not correspond to the speed difference described in the invention.

  Moreover, in the diagonally stretched tenter used in the present invention, it is preferable that the positions of the rail portions and the rail connecting portions can be freely set. Therefore, when an arbitrary entrance width and exit width are set, the stretch ratio corresponding to this is set. be able to.

  In the obliquely stretched tenter used in the present invention, a large bending rate is often required for the rail that regulates the trajectory of the gripping tool. In order to avoid interference between gripping tools due to sudden bending or local stress concentration, it is desirable that the trajectory of the gripping tool draws an arc at the bent portion.

<Earing device>
After the film is stretched by the tenter unit 5, the film is sent out to the ear clip device 6. The side edges of the film are cut off by the edge-cutting device 6, and the ear dust which is the cut-off side edges of the film is cut into small pieces with a cut blower. The cut ear dust pieces are sent to a crusher by an air feeding device and crushed into chips. This chip is reused for dope preparation.

  When the preceding film and the succeeding film are joined by the joining tape, it is necessary to remove the tape from the ear dust in order to reuse it. When bonded by thermal welding or ultrasonic welding, it can be reused in the bonded state. The film from which both side edges are cut off by the edge-cutting device 6 is sent to the heat relaxation unit 7.

<Heat relaxation part>
The heat relaxation unit 7 is provided with a number of rollers, and the film is conveyed through the heat relaxation unit 7 by the rollers. The heat relaxation unit 7 is fed with wind at a desired temperature from a blower to heat-treat the film. It is preferable that the temperature of the wind at this time is 20-250 degreeC.

<Cooling section, winding section>
The film after heat relaxation is sent to the cooling unit 8 and cooled to 30 ° C. or lower, and then sent to the winding unit 9. A winding roller and a press roller are provided inside the winding unit 9. The film sent to the winding unit 9 is wound up by a winding roller. At this time, it is pressed by a press roller and wound up.

(Joint film shape before and after stretching)
In the present invention, the leading end of the succeeding polymer film is bonded to the trailing end of the preceding polymer film, and the polymer film is heated while continuously transporting the bonded polymer film. In addition, both ends are supported by a plurality of gripping tools and obliquely stretched at an angle that makes an angle with the width direction of the polymer film within a range of 40 ° to 50 °. Further, in the elongated polymer film after stretching, the joining line of the joining portion of the leading end portion of the preceding polymer film and the leading end portion of the succeeding polymer film and the width direction (a) of the polymer film The formed angle φ ₁ is -10 ° ≦ φ ₁ ≦ 10 °. This feature will be described with reference to FIG. 2 in which the shape of the bonded portion before and after stretching of the film is shown.

In the present invention, the bonding is performed such that an angle (φ ₁ ) between the stretched bonding line and the width direction (a) is −10 ° ≦ φ ₁ ≦ 10 °. And φ ₁ is preferably −5 ° ≦ φ ₁ ≦ 5 °.

The sign of the angle φ ₀ formed between the joining line before stretching and the width direction a and the sign of the angle φ ₁ formed between the joining line after stretching and the width direction a are shown in FIG. When the film is viewed so that the small turning (SD) side is on the left, the large turning (LD) side is on the right, and the transport direction is on the top of the oblique stretching device, plus the case where the joining line faces from the upper left to the lower right, from the upper right The case where it is directed to the lower left is defined as minus (hereinafter, when there is no particular sign, it means plus).

Joining is performed by adjusting the angle (φ ₀ ) between the joining line before stretching and the width direction (a) so that φ ₁ has such an angle. When phi ₁ is within this range, it is possible to suppress the in-plane orientation angle of the film near the junction at the junction due is disturbed. In the case of | φ ₁ |> 10 °, the in-plane orientation angle of the film around the joint varies, and when the display device is made, the visibility becomes uneven or the stereoscopic image display device is made. In addition, it causes crosstalk.

(Joining method)
As a bonding method, existing means such as double-sided tape, solvent welding, heat welding, ultrasonic welding, and laser welding can be used. In the present invention, it is preferable to bond by ultrasonic welding.

<Ultrasonic welding>
Ultrasonic welding is a method in which electric energy is converted into mechanical vibration energy, and at the same time, pressure is applied to generate strong frictional heat on the bonding surface of the film to melt and bond the resin. For example, the film can be mechanically vibrated at an amplitude of 0.05 mm and 20,000 to 28,000 times per second to generate heat and be instantly welded.

  It is preferable that the width of the bonding line of the bonding portion is 5 mm or less, preferably 2 mm or less, from the viewpoints of preventing occurrence of slipping and bonding strength.

  It is possible to weld the joint part so as to be within 1.1 to 1.5 times the average film thickness of the film to be joined by pressurization. Therefore, it is preferable.

  It is preferable that the width end portion of the joining line is further heated so that the film thickness of the end portion is 1.3 times or less with respect to the film thickness of the film. In this way, when the tenter unit 5 is gripped with a gripping tool (for example, a gripping tool) and stretched, the force applied to the gripping tool and the distortion to the film are almost the same in the joining line and other parts. And breakage can be avoided.

  In addition, the resin melted at the time of welding may protrude from the width end portion, and this portion may be a cause of catching in a later process or when the end portion of the tenter portion 5 is gripped with a gripping tool and stretched. Since it contacts and contaminates a holding | grip tool, it is preferable to remove. Examples of the removal method include a method using a laser cutter and a method using a rotary die cutter, but cutting with a laser cutter is preferable.

<Heat welding>
The heat welding is performed using, for example, a heat sealer device (as shown in FIG. 2 of JP 2009-90651 A). The heat sealer is heated and welded with a heater so as to sandwich the film conveyance path from above and below. The heater is temperature controlled within a predetermined temperature range that dissolves the film but does not decompose it. When the upper and lower heaters are in contact with a region where the films are overlapped for a predetermined time, a part of the film is melted and bonded, and the preceding film and the succeeding film can be joined.

<Laser welding>
The laser welding apparatus irradiates a welding laser beam along the joining line from above the film. The welding laser beam melts and joins the preceding film and the following film. At this time, the laser welding apparatus irradiates the welding laser beam with the upper surface of the preceding film (the lower surface of the subsequent film) as the focal position. When the welding laser beam is irradiated, heat is generated and melted on the upper surface of the preceding film, and the heat is transmitted to the lower surface of the succeeding film and melted. Thereby, a preceding film and a succeeding film are welded (joined) at the portion of the joining line.

<Tape bonding>
In the case of joining with a tape, it is preferable to use a double-sided tape in which an adhesive layer is provided on both surfaces of a base material that exhibits substantially the same stretching behavior as the film in the stretching temperature range.

(Polymer film substrate)
As the polymer film substrate according to the present invention, a thermoplastic resin is mainly used, and polycarbonate, polyester, polyethersulfone, polyarylate, polyimide, polyolefin and the like as general optical film resins can be used. Further, polyethylene terephthalate, polyimide, polymethyl methacrylate, polysulfone, polyethylene, polychlorinated vinyl, alicyclic olefin polymer, acrylic polymer, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, or the like may be used. In particular, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, an acrylic polymer having a lactone ring structure, and the like are more preferable. These raw materials may be used alone or in combination with different thermoplastic resins. When mixed and used, a mixture of cellulose acetate and an acrylic polymer is more preferable.

  Transparent polymers are blended appropriately with colorants such as pigments and dyes, optical brighteners, dispersants, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. It may be what was done.

  The film may be a single layer film or a multilayer film.

  As the film, an unpolymer film is mainly used, but a film that has already been subjected to any one of longitudinal stretching, lateral stretching, and oblique stretching alone or a plurality of times may be used.

<Cellulose ester>
Although the polymer film of this invention can be produced using various resin base materials, it is preferable that it is an aspect containing a cellulose ester.

  The cellulose ester that can be used in the present invention is at least selected from cellulose (di, tri) acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose phthalate. One type is preferred.

  Among these, particularly preferable cellulose esters include cellulose triacetate, cellulose diacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate.

  As a substitution degree of the mixed fatty acid ester, when having an acyl group having 2 to 4 carbon atoms as a substituent, when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group or butyryl group is Y, A cellulose ester that simultaneously satisfies the following formulas (I) and (II) is preferred.

Formula (I) 2.0 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5
Furthermore, the cellulose ester used in the present invention preferably has a weight average molecular weight Mw / number average molecular weight Mn ratio of 1.5 to 5.5, particularly preferably 2.0 to 5.0, Preferably it is 2.5-5.0, More preferably, the cellulose ester of 3.0-5.0 is used preferably.

  The cellulose ester raw material cellulose used in the present invention may be wood pulp or cotton linter, and the wood pulp may be softwood or hardwood, but softwood is more preferred. A cotton linter is preferably used from the viewpoint of peelability during film formation. The cellulose ester made from these can be mixed suitably or can be used independently.

  For example, the ratio of cellulose ester derived from cellulose linter: cellulose ester derived from wood pulp (coniferous): cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50:50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, 40:30:30.

  In the present invention, 1 g of cellulose ester is added to 20 ml of pure water (electric conductivity of 0.1 μS / cm or less, pH 6.8), and the pH when stirred in a nitrogen atmosphere at 25 ° C. for 1 hr is 6 to 6. 7. It is preferable that the electric conductivity is 1 to 100 μS / cm.

  In addition, as long as the effect of this invention is not impaired, thermoplastic resins other than the said cellulose acetate can also be used together for the polymer film of this invention. The thermoplastic resin component to be mixed is preferably one having excellent compatibility with the cellulose ester, and the transmittance when formed into a film is preferably 80% or more, more preferably 90% or more, and further preferably 92% or more.

  General thermoplastic resins include polyethylene (PE), high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene (PS). Polyvinyl acetate (PVAc), Teflon (registered trademark) (polytetrafluoroethylene, PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), and the like can be used.

  When strength and resistance to breakage are particularly required, polyamide (PA), nylon, polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate (PBT) ), Polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP), and the like.

  Furthermore, when high heat distortion temperature and long-term use characteristics are required, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, polyether Ether ketone, thermoplastic polyimide (PI), polyamideimide (PAI), or the like can be used.

  In addition, it is possible to perform the kind of resin and the combination of molecular weight according to the use of this invention.

  In addition, cellulose ester is synthesized industrially using sulfuric acid as a catalyst, but this sulfuric acid is not completely removed, and the residual sulfuric acid causes various decomposition reactions during melt film formation, resulting in cellulose ester obtained. In order to affect the quality of the film, the content of residual sulfuric acid in the cellulose ester used in the present invention is preferably in the range of 0.1 to 40 ppm in terms of elemental sulfur. These are considered to be contained in the form of salts. If the residual sulfuric acid content exceeds 40 ppm, the deposit on the die lip during heat melting increases, such being undesirable. Moreover, since it becomes easy to fracture | rupture at the time of slitting at the time of hot drawing or after hot drawing, it is not preferable. A smaller amount is preferable, but if it is less than 0.1, it is not preferable because the load of the cellulose ester washing process becomes too large, and it is not preferable because it may easily break. This is not well understood, although an increase in the number of washings may affect the resin. Furthermore, the range of 0.1-30 ppm is preferable. The residual sulfuric acid content can be similarly measured by ASTM-D817-96.

  Further, the total residual acid amount including other (such as acetic acid) residual acids is preferably 1000 ppm or less, more preferably 500 ppm or less, and even more preferably 100 ppm or less.

  For washing cellulose ester, in addition to water, a poor solvent such as methanol or ethanol, or, as a result, a mixed solvent of a poor solvent and a good solvent can be used as long as it is a poor solvent. Organic impurities can be removed.

  In order to improve the heat resistance, mechanical properties, optical properties, etc. of cellulose ester, it can be dissolved in a good solvent of cellulose ester and then reprecipitated in a poor solvent to remove low molecular weight components and other impurities of cellulose ester. it can. Furthermore, another polymer or a low molecular weight compound may be added after the cellulose ester reprecipitation treatment.

  Moreover, it is preferable that the cellulose ester used by this invention is a thing with few bright spot foreign materials when it is made into a film. A bright spot foreign material is an arrangement in which two polarizing plates are arranged orthogonally (crossed Nicols), a cellulose ester film is placed between them, light from the light source is applied from one side, and the cellulose ester film is applied from the other side. This is the point where the light from the light source appears to leak when observed. At this time, the polarizing plate used for the evaluation is desirably composed of a protective film having no bright spot foreign matter, and a polarizing plate using a glass plate for protecting the polarizer is preferably used. The cause of bright spot foreign matter is considered to be one of the causes of unacetylated or low acetylated cellulose contained in the cellulose ester. Use a cellulose ester with little bright spot foreign matter and filter the melted cellulose ester or cellulose ester solution. In at least one of the later stage of synthesis of cellulose ester and the process of obtaining a precipitate, the bright spot foreign matter can be removed once again in the solution state via the filtration step. Since the molten resin has a high viscosity, the latter method is more efficient.

  The polymer film of the present invention may be appropriately mixed with polymer components other than the cellulose ester described later.

<Polymer or oligomer>
The polymer film of the present invention has 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 has a weight average molecular weight in the range of 500 to 200,000. It is also preferable to contain a polymer or oligomer of a certain vinyl compound. The mass ratio of the content of the cellulose ester and the polymer or oligomer is preferably in the range of 95: 5 to 50:50.

  Hereinafter, the polymer or oligomer used in the present invention will be described.

The carboxyl group is a group having a structure of —COO—. An amino group is a group having a structure of —NR ₁ (R ₂ ), and R ₁ and R ₂ each represent a substituent such as a hydrogen atom, an alkyl group, or a phenyl group. The amide group is a group having a structure of —NHCO—, and a substituent such as an alkyl group or a phenyl group may be linked thereto.

  Examples of the polymer and oligomer used in the present invention include the following acrylic polymers and oligomers.

  These compounds are preferably used in the range of 5 to 50% by mass with respect to the cellulose ester, and are preferably excellent in compatibility. The transmittance is 80% over the entire visible range (400 nm to 800 nm) when formed into a film. Thus, 90% or more, more preferably 92% or more is obtained.

<Acrylic polymer and oligomer>
The acrylic polymer and oligomer used in the present invention are not particularly limited in structure, but a polymer having a weight average molecular weight of 500 or more and 200,000 or less obtained by polymerizing an ethylenically unsaturated monomer. It is preferable that

  The acrylic polymer and oligomer used in the present invention may be composed of a single monomer or a plurality of types of monomers. The monomer is preferably selected from acrylic acid ester or methacrylic acid ester, but appropriately contains other monomers such as maleic anhydride, styrene, etc. depending on the retardation characteristics, wavelength dispersion characteristics, and heat resistance of the film to be produced. It does not matter.

  Hereinafter, the acrylic polymer and oligomer used in the present invention will be described as polymer X.

<Polymer X>
Polymer X used in the present invention is a copolymer of ethylenically unsaturated monomer Xa having no aromatic ring and polar group in the molecule and ethylenically unsaturated monomer Xb having no aromatic ring and having a polar group in the molecule. A polymer represented by the following general formula (1) having a weight average molecular weight of 500 to 200,000 is preferred. Furthermore, it is preferable that it is solid under 30 degreeC, or a glass transition temperature is 35 degreeC or more.

  When the weight average molecular weight is 500 to 200,000, the compatibility with the cellulose ester and the transparency are excellent.

General formula (1):-[Xa] m- [Xb] n-
(M and n represent molar composition ratios, and m + n = 100.)
Although the monomer as a monomer unit which comprises the polymer X used for this invention is mentioned below, it is not limited to this.

  Examples of the ethylenically unsaturated monomer Xa having no aromatic ring and no polar group in the molecule include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), and butyl acrylate (n-, i-, s-, t-), pentyl acrylate (n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid (ε-caprolactone), acrylic acid (2-hydroxyethyl) , Acrylic acid (2-ethoxyethyl), or the like, or those obtained by replacing the acrylic ester with a methacrylic ester. Among these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and propyl methacrylate (i-, n-) are preferable.

  The ethylenically unsaturated monomer Xb having no polar ring in the molecule and having a polar group is preferably acrylic acid or methacrylic acid ester as a monomer unit having a hydroxyl group (hydroxyl group). For example, (meth) acrylic acid 2 -Hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, (meth) acrylic acid 10 Hydroxyl group-containing monomers such as hydroxydecyl, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate; (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate , Itacon Carboxyl group-containing monomers such as maleic acid, fumaric acid and crotonic acid; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrene sulfonic acid and allyl sulfonic acid, 2- ( Sulfonic acid group-containing monomers such as (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid; 2-hydroxyethylacryloyl phosphate, etc. And phosphoric acid group-containing monomers.

  In addition, (N-substituted) amides such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, etc. Monomer; (meth) acrylic acid aminoethyl, (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid t-butylaminoethyl and other (meth) acrylic acid alkylaminoalkyl monomers; (meth) acrylic (Meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl acid and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- ( (Meta) acryloyl- - oxy octamethylene succinimide, also including succinimide-based monomers such as N- acryloyl morpholine and the like as a monomer Examples of the reforming purposes.

  Further, vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N-vinyl carboxylic acid amide , Vinyl monomers such as styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; (meth) acrylic Polyethylene glycol acid, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, methoxypolypropylene (meth) acrylate Glycol acrylic ester monomers such as recall; (meth) acrylic acid tetrahydrofurfuryl, fluorine (meth) acrylate, silicone (meth) acrylate and acrylic acid ester monomers such as 2-methoxyethyl acrylate, etc. may also be used.

  In the present invention, the polymer X is synthesized by copolymerization using the hydrophobic monomer Xa and the polar monomer Xb. Further, the above-described hydrophobic monomer or polar monomer can be used as the monomer Xc to form a terpolymer.

  The use ratio in the synthesis of the hydrophobic monomer Xa and the polar monomer Xb is preferably in the range of 99: 1 to 50:50, more preferably in the range of 95: 5 to 60:40. When the use ratio of the hydrophobic monomer Xa is large, the compatibility with the cellulose ester is lowered, but the effect of reducing the fluctuation of the retardation value with respect to the environmental humidity is high. When the use ratio of the polar monomer Xb is large, the compatibility with the cellulose ester is improved, but the fluctuation of the retardation value with respect to the environmental humidity is increased. Moreover, since the haze comes out at the time of film forming when the usage-amount of polar monomer Xb exceeds the said range, it is unpreferable.

  In order to synthesize such a polymer, it is difficult to control the molecular weight in normal polymerization, and it is desirable to use a method that can align the molecular weight as much as possible by a method that does not increase the molecular weight so much. Such polymerization methods include a method using a peroxide polymerization initiator such as cumene peroxide and t-butyl hydroperoxide, a method using a polymerization initiator in a larger amount than normal polymerization, and a mercapto compound in addition to the polymerization initiator. And a method using a chain transfer agent such as carbon tetrachloride, a method using a polymerization terminator such as benzoquinone and dinitrobenzene in addition to the polymerization initiator, and further disclosed in JP-A No. 2000-128911 or 2000-344823. Examples include a compound having one thiol group and a secondary hydroxyl group (hydroxyl group), or a bulk polymerization method using a polymerization catalyst in which the compound and an organometallic compound are used in combination. It is preferably used in the present invention.

  The weight average molecular weight of the polymer X used in the present invention can be adjusted by a known molecular weight adjusting method. Examples of such a molecular weight adjusting method include a method of adding a chain transfer agent such as carbon tetrachloride, lauryl mercaptan, octyl thioglycolate, and the like. The polymerization temperature is usually from room temperature to 130 ° C., preferably from 50 ° C. to 100 ° C., but this temperature or the polymerization reaction time can be adjusted.

  The measuring method of a weight average molecular weight can be based on the said molecular weight measuring method.

  The amount of the polymer X added is appropriately adjusted so that the film has a desired performance. Addition to reduce fluctuation of photoelastic coefficient and retardation value with respect to environmental humidity. Addition of small amount to increase retardation performance. , Corner irregularities that change the color of the corners of the screen, and even if the phase difference value changes from the initially set value, the viewing angle fluctuates and the color changes. Since phase difference performance cannot be obtained, 5 mass% or more and 50 mass% or less are preferable.

<Others: Additive>
The polymer film of the present invention can contain various additives depending on the purpose. Hereinafter, main additives will be described.

(Sugar ester compound)
Examples of the polyester resin that can be contained in the polymer film of the present invention include sugar ester compounds.

  Examples of the sugar ester compound include an ester compound in which at least one pyranose structure or at least one furanose structure is 1 to 12 and all or part of the OH groups in the structure are esterified.

  The proportion of esterification is preferably 70% or more of the OH groups present in the pyranose structure or furanose structure.

  Examples of the sugar as a raw material for synthesizing the sugar ester compound include the following, but the present invention is not limited thereto.

  Glucose, galactose, mannose, fructose, xylose or arabinose, lactose, sucrose, nystose, 1F-fructosyl nystose, stachyose, maltitol, lactitol, lactulose, cellobiose, maltose, cellotriose, maltotriose, raffinose or kestose .

  In addition, gentiobiose, gentiotriose, gentiotetraose, xylotriose, galactosyl sucrose, and the like are also included.

  Among these compounds, compounds having both a pyranose structure and a furanose structure are particularly preferable.

  Examples include sucrose, kestose, nystose, 1F-fructosyl nystose, stachyose, and more preferably sucrose.

  The monocarboxylic acid used for esterifying all or part of the OH groups in the pyranose structure or furanose structure is not particularly limited, and known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic A group monocarboxylic acid or the like can be used. The carboxylic acid used may be one kind or a mixture of two or more kinds.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid , Saturated fatty acids such as tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid, Examples include unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octenoic acid.

  Examples of preferable alicyclic monocarboxylic acids include acetic acid, cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include aromatic monocarboxylic acids having an alkyl group or alkoxy group introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, cinnamic acid, benzylic acid, biphenylcarboxylic acid, and naphthalene. Examples thereof include aromatic monocarboxylic acids having two or more benzene rings such as carboxylic acid and tetralincarboxylic acid, or derivatives thereof. More specifically, xylyl acid, hemelic acid, mesitylene acid, prenylic acid, γ-isoduric acid, jurylic acid, mesitic acid, α-isoduric acid, cumic acid, α-toluic acid, hydroatropic acid, atropic acid, hydrocinnamic acid, salicylic acid, o-anisic acid, m-anisic acid, p-anisic acid , Creosote acid, o-homosalicylic acid, m-homosalicylic acid, p-homosalicylic acid, o-pyrocate Acid, β-resorcylic acid, vanillic acid, isovanillic acid, veratromic acid, o-veratrumic acid, gallic acid, asaronic acid, mandelic acid, homoanisic acid, homovanillic acid, homoveratrumic acid, o-homoveratrumic acid, phthalonic acid, p-coumaric Examples of the acid include benzoic acid.

  As a compound having 1 to 12 at least one of pyranose structural units or furanose structural units, an oligosaccharide ester compound can be applied.

  Oligosaccharides are produced by allowing an enzyme such as amylase to act on starch, sucrose, etc., and examples of the oligosaccharides include maltooligosaccharide, isomaltooligosaccharide, fructooligosaccharide, galactooligosaccharide, and xylo-oligosaccharide. .

  Examples of sugar ester compounds are listed below, but the present invention is not limited thereto.

Monopet SB: manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Monopet SOA: manufactured by Daiichi Kogyo Seiyaku Co., Ltd. The addition amount of these sugar ester compounds is 0.5 with respect to the total mass of the polymer (X) and the cellulose ester. It is preferable to contain -30 mass%, and it is preferable to contain 5-20 mass% especially.

(Plasticizer)
The polymer film of the present invention can contain a plasticizer. The plasticizer is not particularly limited, but is preferably a polycarboxylic acid ester plasticizer, a glycolate plasticizer, a phthalate ester plasticizer, a fatty acid ester plasticizer, a polyhydric alcohol ester plasticizer, or a polyester. It is selected from plasticizers, acrylic plasticizers and the like. Of these, when two or more plasticizers are used, at least one plasticizer is preferably a polyhydric alcohol ester plasticizer.

  The polyhydric alcohol ester plasticizer is a plasticizer comprising an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule. Preferably it is a 2-20 valent aliphatic polyhydric alcohol ester.

  The polyhydric alcohol preferably used in the present invention is represented by the following general formula (2).

General formula (2): Ra- (OH) _n
(However, Ra represents an n-valent organic group, n represents a positive integer of 2 or more, and an OH group represents an alcoholic and / or phenolic hydroxyl group (hydroxyl group).)
Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these. Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane- Examples include 1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol and the like. In particular, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable.

  There is no restriction | limiting in particular as monocarboxylic acid used for polyhydric alcohol ester, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred in terms of improving moisture permeability and retention.

  Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. The number of carbon atoms is more preferably 1-20, and particularly preferably 1-10. When acetic acid is contained, the compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanoic acid, undecylic acid, lauric acid, tridecylic acid, Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, olein Examples thereof include unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid.

  Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include those in which 1 to 3 alkoxy groups such as alkyl group, methoxy group or ethoxy group are introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, biphenylcarboxylic acid, Examples thereof include aromatic monocarboxylic acids having two or more benzene rings such as naphthalenecarboxylic acid and tetralincarboxylic acid, or derivatives thereof. Benzoic acid is particularly preferable.

  The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably 300 to 1500, and more preferably 350 to 750. A higher molecular weight is preferred because it is less likely to volatilize, and a smaller one is preferred in terms of moisture permeability and compatibility with cellulose ester.

  The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.

  The glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used. Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.

  Examples of the phthalate ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, and dicyclohexyl terephthalate.

  Examples of the citrate plasticizer include acetyl trimethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate.

  Examples of fatty acid ester plasticizers include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.

  Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like.

  The polyvalent carboxylic acid ester compound is composed of an ester of divalent or higher, preferably divalent to 20 valent polyvalent carboxylic acid and alcohol. The aliphatic polyvalent carboxylic acid is preferably 2 to 20 valent, and in the case of an aromatic polyvalent carboxylic acid or an alicyclic polyvalent carboxylic acid, it is preferably 3 to 20 valent.

  The polyvalent carboxylic acid is represented by the following general formula (3).

General formula (3): Rb (COOH) _m (OH) _n
(Where Rb is an (m + n) -valent organic group, m is a positive integer of 2 or more and 6 or less, n is an integer of 0 or more and 4 or less, a COOH group is a carboxyl group, and an OH group is an alcoholic or phenolic hydroxyl group. Represents a group (hydroxyl group).
Examples of preferred polyvalent carboxylic acids include the following, but the present invention is not limited to these. Trivalent or higher polyvalent aromatic polycarboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid or derivatives thereof, succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid, fumaric acid, maleic acid, tetrahydrophthal An aliphatic polyvalent carboxylic acid such as an acid, an oxypolyvalent carboxylic acid such as tartaric acid, tartronic acid, malic acid and citric acid can be preferably used. In particular, it is preferable to use an oxypolycarboxylic acid from the viewpoint of improving retention.

  There is no restriction | limiting in particular as alcohol used for the said polyhydric carboxylic acid ester compound, Well-known alcohol and phenols can be used. For example, an aliphatic saturated alcohol or aliphatic unsaturated alcohol having a straight chain or side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10. In addition, alicyclic alcohols such as cyclopentanol and cyclohexanol or derivatives thereof, aromatic alcohols such as benzyl alcohol and cinnamyl alcohol, or derivatives thereof can also be preferably used.

  When an oxypolycarboxylic acid is used as the polycarboxylic acid, the alcoholic or phenolic hydroxyl group (hydroxyl group) of the oxypolycarboxylic acid may be esterified with a monocarboxylic acid. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid, Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid, undecylenic acid, olein Examples thereof include unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid.

  Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. Aromatic monocarboxylic acids possessed by them, or derivatives thereof.

  Of these monocarboxylic acids, acetic acid, propionic acid, and benzoic acid are particularly preferable.

  The molecular weight of the polyvalent carboxylic acid ester compound is not particularly limited, but is preferably in the range of 300 to 1000, and more preferably in the range of 350 to 750. The larger one is preferable in terms of improvement in retention, and the smaller one is preferable in terms of moisture permeability and compatibility with cellulose ester.

  The alcohol used for the polyvalent carboxylic acid ester may be one kind or a mixture of two or more kinds.

  The acid value of the polyvalent carboxylic acid ester compound is preferably 1 mgKOH / g or less, and more preferably 0.2 mgKOH / g or less. Setting the acid value in the above range is preferable because the environmental fluctuation of the retardation is also suppressed.

(Acid value)
The acid value in the present invention refers to the number of milligrams of potassium hydroxide necessary for neutralizing the acid (carboxyl group present in the sample) contained in 1 g of the sample. The acid value is measured according to JIS K0070.

  Examples of particularly preferred polyvalent carboxylic acid ester compounds are shown below, but the present invention is not limited thereto. For example, triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate, dibutyl tartrate, diacetyl dibutyl tartrate, Examples include tributyl trimellitic acid and tetrabutyl pyromellitic acid.

  The polyester plasticizer is not particularly limited, and a polyester plasticizer having an aromatic ring or a cycloalkyl ring in the molecule can be used. Although it does not specifically limit as a polyester plasticizer, For example, the aromatic terminal ester plasticizer represented by following General formula (4) can be used.

General formula (4): B-COO-((G-O-) _m -CO-A-COO-) _n G-O-CO-B
(In the formula, B represents a benzene ring and may have another substituent. G represents an alkylene group having 2 to 12 carbon atoms, an arylene group having 6 to 12 carbon atoms, or an oxyalkylene having 4 to 12 carbon atoms. Group A represents an alkylene group having 2 to 10 carbon atoms or an arylene group having 4 to 10 carbon atoms, and m and n represent a repeating unit.)
The compound of the general formula (4) includes a benzene monocarboxylic acid group represented by BCOOH, an alkylene glycol group, an oxyalkylene glycol group or an aryl glycol group represented by HO— (GO—) ₁ H, HOCO-A It is synthesized from an alkylenedicarboxylic acid group or aryldicarboxylic acid group represented by —COO—H, and can be obtained by the same reaction as that of a normal polyester plasticizer.

  Examples of the benzene monocarboxylic acid component of the raw material of the polyester plasticizer include, for example, benzoic acid, para-tert-butyl benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethyl benzoic acid, ethyl benzoic acid, normal propyl benzoic acid, There are aminobenzoic acid, acetoxybenzoic acid and the like, and these can be used as one kind or a mixture of two or more kinds, respectively.

  Examples of the alkylene glycol component of the polyester plasticizer include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propane. Diol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl- 1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentane Diol 1,6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1,3-he There are sundiol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, etc., and these glycols are used as one kind or a mixture of two or more kinds. used. In particular, an alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of excellent compatibility with a cellulose ester.

  Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms as the raw material for the aromatic terminal ester include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. , One or a mixture of two or more.

  Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms as the raw material for the aromatic terminal ester include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These are used as one kind or a mixture of two or more kinds. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and the like.

  The polyester plasticizer has a number average molecular weight of preferably 300 to 1500, more preferably 400 to 1000. The acid value is 0.5 mgKOH / g or less, the hydroxyl (hydroxyl) value is 25 mgKOH / g or less, preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl (hydroxyl) value is 15 mgKOH / g or less. is there.

(UV absorber)
The polymer film of the present invention may contain an ultraviolet absorber. The ultraviolet absorber is intended to improve durability by absorbing ultraviolet rays of 400 nm or less, and in particular, the transmittance at a wavelength of 370 nm is preferably 10% or less, more preferably 5% or less, and further Preferably it is 2% or less.

  The ultraviolet absorber is not particularly limited, and examples thereof include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic powders, and the like. It is done.

  For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxyphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (linear and side Chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc., and tinuvin 109, tinuvin 171, tinuvin 234, tinuvin 326, tinuvin 327, tinuvin 328, There are tinuvins such as tinuvin 928, and these are all commercially available products from BASF Japan and can be preferably used.

  The UV absorbers preferably used in the present invention are benzotriazole UV absorbers, benzophenone UV absorbers, and triazine UV absorbers, particularly preferably benzotriazole UV absorbers and benzophenone UV absorbers. .

  In addition, a discotic compound such as a compound having a 1,3,5-triazine ring is also preferably used as the ultraviolet absorber.

  The method of adding the UV absorber can be added to the dope after dissolving the UV absorber in an alcohol such as methanol, ethanol or butanol, an organic solvent such as methylene chloride, methyl acetate, acetone or dioxolane or a mixed solvent thereof. Or you may add directly in dope composition.

  For an inorganic powder that does not dissolve in an organic solvent, a dissolver or a sand mill is used in the organic solvent and the polymer to disperse and then added to the dope.

  The amount of the UV absorber used is not uniform depending on the type of UV absorber, the usage conditions, etc., but when the dry film thickness of the optical film is 30 to 200 μm, it is 0.5 to 10% by mass relative to the polymer. Preferably, 0.6-4 mass% is still more preferable.

(Antioxidant)
The polymer film of the present invention can contain an antioxidant. Antioxidants are also referred to as deterioration inhibitors. When a liquid crystal image display device or the like is placed in a high humidity and high temperature state, the optical film may be deteriorated.

  The antioxidant has a role of delaying or preventing the optical film from being decomposed by, for example, the residual solvent amount of halogen in the optical film or phosphoric acid of the phosphoric acid plasticizer. It is preferable to contain.

  As such an antioxidant, a hindered phenol compound is preferably used. For example, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3 -(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino)- 1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octa Sil-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxy Benzyl) -isocyanurate and the like.

  In particular, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.

  The amount of these compounds added is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm in terms of mass ratio with respect to the total mass of the polymer (X) and the cellulose ester.

(Fine particles)
Fine particles can be added to the polymer film of the present invention.

  As fine particles, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, Mention may be made of magnesium silicate and calcium phosphate. Further, fine particles of an organic compound can also be preferably used. Examples of organic compounds include polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate, polypropyl methacrylate, polymethyl acrylate, polyethylene carbonate, acrylic styrene resin, silicone resin, polycarbonate resin, benzoguanamine resin, melamine resin Also, pulverized and classified products of organic polymer compounds such as polyolefin-based powders, polyester-based resins, polyamide-based resins, polyimide-based resins, polyfluorinated ethylene-based resins, and starches. Alternatively, a polymer compound synthesized by a suspension polymerization method, a polymer compound made spherical by a spray drying method or a dispersion method, or an inorganic compound can be used.

  Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable.

  The average primary particle diameter of the fine particles is preferably 5 to 400 nm, and more preferably 10 to 300 nm.

  These may be mainly contained as secondary aggregates having a particle size of 0.05 to 0.3 μm, and may be contained as primary particles without being aggregated if the particles have an average particle size of 100 to 400 nm. preferable.

  The content of these fine particles in the polymer is preferably 0.01 to 1% by mass, particularly preferably 0.05 to 0.5% by mass.

  Silicon dioxide fine particles are commercially available under the trade names of, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.). it can.

  Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

  Examples of the polymer fine particle resin include a silicone resin, a fluororesin, and an acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of reducing the friction coefficient while keeping the turbidity of the optical film low. In the said optical film, it is preferable that the dynamic friction coefficient of at least one surface is 0.2-1.0.

  Various additives may be batch-added to a dope that is a resin-containing solution before film formation, or an additive solution may be separately prepared and added in-line. In particular, it is preferable to add a part or all of the fine particles in-line in order to reduce the load on the filter medium.

  When the additive solution is added in-line, it is preferable to dissolve a small amount of resin in order to improve mixing with the dope. A preferable amount of the resin is 1 to 10 parts by mass, and more preferably 3 to 5 parts by mass with respect to 100 parts by mass of the solvent.

  In order to perform in-line addition and mixing in the present invention, for example, an in-line mixer such as a static mixer (manufactured by Toray Engineering), SWJ (Toray static type in-tube mixer Hi-Mixer) or the like is preferably used.

<Acrylic polymer>
An acrylic polymer can also be used for the polymer film of the present invention. The acrylic polymer is not particularly limited as long as it is a resin obtained by polymerizing a monomer composition containing (meth) acrylic acid ester as a constituent component. Moreover, what has two or more types of acrylic polymers as a main component may be used.

  The polymer film of the present invention preferably contains a compound having a lactone ring structure described later as an acrylic polymer.

  As said (meth) acrylic acid ester, the compound (monomer) which has a structure represented by General formula (5) can be used, for example.

(Wherein, ^{R 1} and ^{R 2} each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
Also, acrylic esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, benzyl acrylate, etc .; methyl methacrylate, ethyl methacrylate, propyl methacrylate Methacrylic acid esters such as n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. These may be used alone or in combination of two or more. Among these, methyl methacrylate is more preferable from the viewpoint of excellent heat resistance and transparency. In addition, benzyl (meth) acrylate is preferred in terms of increasing positive birefringence (positive phase difference).

  In addition, when introduce | transducing a methacrylic acid benzyl monomer structural unit, the preferable content of the (meth) acrylic acid benzyl monomer structural unit in an acrylic polymer is 5-50 mass%, More preferably, it is 10-40 mass%, More preferably, it is 15-30 mass%.

  Examples of the compound having the structure represented by the general formula (5) include methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, 2- (Hydroxymethyl) normal butyl acrylate, 2- (hydroxymethyl) tert-butyl acrylate, and the like. Among these, methyl 2- (hydroxymethyl) acrylate and 2- (hydroxymethyl) ethyl acrylate are preferable, and methyl 2- (hydroxymethyl) acrylate is particularly preferable in that the effect of improving heat resistance is high. As for the compound represented by General formula (5), only 1 type may be used and 2 or more types may be used together.

  The acrylic polymer may have a structure other than the structure obtained by polymerizing the (meth) acrylic acid ester described above. The structure other than the structure obtained by polymerizing the (meth) acrylic acid ester is not particularly limited, but a hydroxyl group (hydroxyl group) -containing monomer, an unsaturated carboxylic acid, and a monomer represented by the following general formula (6) A polymer structural unit (repeating structural unit) constructed by polymerizing at least one selected from the group consisting of is preferably used.

(Wherein R ¹ represents a hydrogen atom or a methyl group, X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, a —CO—R ² group, or a C— O—R ³ represents a group, Ac represents an acetyl group, R ² and R ³ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
The hydroxyl group (hydroxyl group) -containing monomer is not particularly limited as long as it is a hydroxyl group (hydroxyl group) -containing monomer other than the monomer represented by the general formula (5). For example, methallyl alcohol, allyl 2- (hydroxyalkyl) acrylic acid esters such as alcohol, allyl alcohol such as 2-hydroxymethyl-1-butene, α-hydroxymethylstyrene, α-hydroxyethylstyrene, methyl 2- (hydroxyethyl) acrylate; 2- (Hydroxyalkyl) acrylic acid such as (hydroxyethyl) acrylic acid; and the like. These may be used alone or in combination of two or more.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. These may be used alone or in combination of two or more. May be. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.

  Examples of the compound represented by the general formula (6) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, and vinyl acetate. These may be used alone. Two or more kinds may be used in combination. Among these, styrene and α-methylstyrene are particularly preferable in that the effects of the present invention are sufficiently exhibited.

  The polymerization method is not particularly limited, and a known polymerization method can be used. A suitable method may be employed depending on the type of monomer (monomer composition) to be used, the use ratio, and the like.

  The acrylic polymer used in the present invention has a glass transition temperature (Tg) of preferably 110 ° C to 200 ° C, more preferably 115 ° C to 200 ° C, still more preferably 120 ° C to 200 ° C, and particularly preferably 125 ° C. It is -190 degreeC, Most preferably, it is 130 to 180 degreeC.

  In terms of heat resistance, N-substituted maleimides such as phenylmaleimide, cyclohexylmaleimide, and methylmaleimide may be copolymerized in the molecular chain (also referred to as the main skeleton of the polymer or the main chain). A lactone ring structure, a glutaric anhydride structure, a glutarimide structure, or the like may be introduced. Among them, a monomer that does not contain a nitrogen atom is preferable from the viewpoint of difficulty in coloring (yellowing) the film, and positive birefringence (positive phase difference) is easily expressed in the main chain. Those having a lactone ring structure are preferred.

  Regarding the lactone ring structure in the main chain, a 4- to 8-membered ring may be used, but a 5- to 6-membered ring is more preferable, and a 6-membered ring is more preferable in view of the stability of the structure. Moreover, when the lactone ring structure in the main chain is a 6-membered ring, examples include the structure represented by the general formula (7) and Japanese Patent Application Laid-Open No. 2004-168882, and the lactone ring structure is introduced into the main chain. The point of high polymerization yield in the synthesis of the previous polymer, the point that a polymer with a high content of lactone ring structure is easily obtained with high polymerization yield, and (meth) acrylic acid esters such as methyl methacrylate It is preferable that it is a structure represented by General formula (7) at the point with good copolymerizability.

  When the acrylic polymer is a resin obtained by polymerizing a monomer containing a compound having a structure represented by the general formula (5), the acrylic polymer has a lactone ring structure. Is more preferable (hereinafter, an acrylic polymer having a lactone ring structure is referred to as a “lactone ring-containing polymer”). Hereinafter, the lactone ring-containing polymer will be described.

  The cellulose ester film according to the present invention preferably uses a compound having a lactone ring structure.

  Examples of the lactone ring structure include a structure represented by the following general formula (7).

(Wherein R ¹ , R ² and R ³ each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
The organic residue in the general formula (7) is not particularly limited as long as it has a carbon number in the range of 1 to 20, but for example, a linear or branched alkyl group, a linear or branched alkylene Group, aryl group, -OAc group, -CN group and the like.

  The content of the lactone ring structure in the acrylic polymer is preferably in the range of 5 to 90% by mass, more preferably in the range of 20 to 90% by mass, and still more preferably in the range of 30 to 90% by mass. More preferably, it is in the range of 35 to 90% by mass, particularly preferably in the range of 40 to 80% by mass, and most preferably in the range of 45 to 75% by mass. If the content of the lactone ring structure is more than 90% by mass, the moldability becomes poor. Moreover, there exists a tendency for the flexibility of the obtained film to fall, and it is not preferable. When the content of the lactone ring structure is less than 5% by mass, it is difficult to obtain a necessary retardation when formed into a film, and heat resistance, solvent resistance, and surface hardness may be insufficient. It is not preferable.

  In the lactone ring-containing polymer, the content ratio of the structure other than the lactone ring structure represented by the general formula (7) is that of the polymer structural unit (repeating structural unit) constructed by polymerizing the (meth) acrylic acid ester. In the range of 10 to 95% by mass, more preferably in the range of 10 to 80% by mass, further preferably in the range of 10 to 65% by mass, particularly preferably in the range of 20 to 60% by mass, Preferably it exists in the range of 25-55 mass%. In the case of a polymer structural unit (repeating structural unit) constructed by polymerizing a hydroxyl group (hydroxyl group) -containing monomer, it is preferably in the range of 0 to 30% by mass, more preferably in the range of 0 to 20% by mass. More preferably, it is in the range of 0 to 15% by mass, particularly preferably in the range of 0 to 10% by mass. In the case of a polymer structural unit (repeating structural unit) constructed by polymerizing an unsaturated carboxylic acid, it is preferably in the range of 0 to 30% by mass, more preferably in the range of 0 to 20% by mass, and still more preferably 0. It is in the range of ˜15% by mass, particularly preferably in the range of 0 to 10% by mass.

  The method for producing the lactone ring-containing polymer is not particularly limited, but preferably the polymer obtained after obtaining a polymer having a hydroxyl group (hydroxyl group) and an ester group in the molecular chain by a polymerization step. A lactone ring-containing polymer can be obtained by performing a lactone cyclization condensation step of introducing a lactone ring structure into the polymer by heat treatment.

<Alicyclic polyolefin resin>
In the present invention, an alicyclic polyolefin resin can also be used as the resin film substrate.

  The alicyclic polyolefin resin is an amorphous resin having an alicyclic structure in the main chain and / or side chain. Examples of the alicyclic structure in the alicyclic polyolefin resin include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene) structure. From the viewpoint of mechanical strength, heat resistance, and the like. A cycloalkane structure is preferred. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15, when the mechanical strength, heat resistance, In addition, the moldability characteristics of the film are highly balanced and suitable.

  The ratio of the repeating unit having an alicyclic structure constituting the alicyclic polyolefin resin is preferably 55% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more. It is preferable from a viewpoint of transparency and heat resistance that the ratio of the repeating unit which has an alicyclic structure in alicyclic polyolefin resin exists in this range.

  Examples of the alicyclic polyolefin resin include a norbornene resin, a monocyclic olefin resin, a cyclic conjugated diene resin, a vinyl alicyclic hydrocarbon resin, and hydrides thereof. Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

  Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, or a hydride thereof; norbornene structure The addition polymer of the monomer which has this, the addition copolymer of the monomer which has a norbornene structure, and another monomer, those hydrides, etc. can be mentioned. Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. Can be used.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene) and tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene. (Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0. 1 ^2,5 . 1 ^7,10 ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. In addition, these substituents may be the same or different and a plurality may be bonded to the ring. Monomers having a norbornene structure can be used singly or in combination of two or more.

  Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group. To obtain a film with a small saturated water absorption rate. It is preferable that the amount of polar groups is small, and it is more preferable that there are no polar groups.

  Other monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof; cyclic conjugated dienes such as cyclohexadiene and cycloheptadiene; Derivatives thereof; and the like.

  A ring-opening polymer of a monomer having a norbornene structure and a ring-opening copolymer of a monomer having a norbornene structure and another monomer copolymerizable with the monomer have a known ring-opening polymerization catalyst. It can be obtained by (co) polymerization in the presence.

  Examples of other monomers that can be addition copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, Cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and the like. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable.

  An addition polymer of a monomer having a norbornene structure and an addition copolymer of another monomer copolymerizable with a monomer having a norbornene structure can be used in the presence of a known addition polymerization catalyst. It can be obtained by polymerization.

  Hydrogenated product of ring-opening polymer of monomer having norbornene structure, hydrogenated product of ring-opening copolymer of monomer having norbornene structure and other monomer capable of ring-opening copolymerization, norbornene structure The hydride of an addition polymer of a monomer having a hydride, and the hydride of an addition copolymer of a monomer having a norbornene structure and another monomer capable of addition copolymerization with these cyclization (co-opening) ) A known hydrogenation catalyst containing a transition metal such as nickel or palladium is added to a polymer or addition (co) polymer solution, and brought into contact with hydrogen, so that the carbon-carbon unsaturated bond is preferably 90% or more. It can be obtained by hydrogenation.

Among norbornene-based resins, as a repeating unit, A: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and B: tricyclo [4.3.0.1 ^2,5 ] decane-7 , 9-diyl-ethylene structure, the content of these repeating units is 90% by mass or more based on the entire repeating units of the norbornene resin, and the content ratio of A and the content ratio of B Is preferably 100: 0 to 40:60 in mass ratio of A: B. By using such a resin, it is possible to obtain an optical film that has no dimensional change in the long term and is excellent in stability of optical characteristics.

  The molecular weight of the alicyclic polyolefin resin suitably used in the present invention is appropriately selected according to the purpose of use, but it is determined by gel permeation chromatography using cyclohexane (toluene when the resin is not dissolved) as a solvent. The weight average molecular weight (Mw) of isoprene (in terms of polystyrene when the solvent is toluene) is usually 15,000 to 50,000, preferably 18,000 to 45,000, more preferably 20,000 to 40,000. It is. When the weight average molecular weight is in such a range, the mechanical strength and formability of the film are highly balanced, which is preferable.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic polyolefin resin suitably used in the present invention is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1 to 4.0, more preferably in the range of 1.2 to 3.5.

<Production example of raw film>
As a manufacturing method of the raw film which concerns on this invention, you may manufacture by any method of a solution casting film forming method or a melt casting film forming method. Hereinafter, as a typical example, a solution casting film forming method of a cellulose ester film will be described.

  The cellulose ester film was produced by dissolving the cellulose ester and the plasticizer and other additives in a solvent to prepare a dope, casting the dope on a belt-shaped or drum-shaped metal support, and casting. It is performed by a step of drying the dope as a web, a step of peeling from the metal support, a step of stretching, a step of further drying, a step of further heat-treating the obtained film if necessary, and a step of winding after cooling. The cellulose ester film according to the present invention preferably contains 60 to 95% by mass of cellulose ester in the solid content.

  The process for preparing the dope will be described. The concentration of cellulose ester in the dope is preferably higher because the drying load after casting on the metal support can be reduced. However, if the concentration of cellulose ester is too high, the load during filtration increases and the filtration accuracy increases. Becomes worse. As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%.

  Organic solvents that dissolve cellulose esters and are useful for forming cellulose ester solutions or dopes include chlorinated organic solvents and non-chlorinated organic solvents. Methylene chloride (methylene chloride) can be mentioned as a chlorinated organic solvent, and it is suitable for dissolving cellulose esters, particularly cellulose triacetate. Due to recent environmental problems, the use of non-chlorine organic solvents has been studied. Examples of the non-chlorine organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1, Examples include 1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, and the like. When these organic solvents are used for cellulose triacetate, a dissolution method at room temperature can be used, but an insoluble material can be obtained by using a dissolution method such as a high-temperature dissolution method, a cooling dissolution method, or a high-pressure dissolution method. Can be reduced, which is preferable. Methylene chloride can be used for cellulose esters other than cellulose triacetate, but methyl acetate, ethyl acetate, and acetone are preferably used. Particularly preferred is methyl acetate. In the present invention, an organic solvent having good solubility with respect to the cellulose ester is referred to as a good solvent, and has a main effect on dissolution, and an organic solvent used in a large amount among them is a main (organic) solvent or a main ( Organic) solvent.

  The dope used in the present invention preferably contains 1 to 40% by mass of an alcohol having 1 to 4 carbon atoms in addition to the organic solvent. These are gelling solvents that make dope film (web) gel when the dope is cast on a metal support and the solvent starts to evaporate and the ratio of alcohol increases, making the web strong and easy to peel off from the metal support. When these ratios are small, there is also a role of promoting the dissolution of the cellulose ester of the non-chlorine organic solvent. Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Of these, ethanol is preferred because it has excellent dope stability, has a relatively low boiling point, and has good drying properties. These organic solvents are called poor solvents because they are not soluble in cellulose esters alone.

  It is preferable that the concentration of the cellulose ester in the dope is adjusted to 15 to 30% by mass and the dope viscosity is adjusted to a range of 100 to 500 Pa · s in order to obtain good film surface quality.

  A general method can be used as a dissolution method of the cellulose ester when preparing the dope described above. When heating and pressurization are combined, it is possible to heat above the boiling point at normal pressure. It is preferable to stir and dissolve while heating at a temperature that is equal to or higher than the boiling point of the solvent at normal pressure and that the solvent does not boil under pressure, in order to prevent the generation of massive undissolved materials called gels and mamacos. Moreover, after mixing a cellulose ester with a poor solvent and making it wet or swell, the method of adding a good solvent and melt | dissolving is also used preferably.

  The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

  The heating temperature with the addition of a solvent is preferably higher from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates. A preferable heating temperature is 45 to 120 ° C, more preferably 60 to 110 ° C, and still more preferably 70 ° C to 105 ° C. The pressure is adjusted so that the solvent does not boil at the set temperature.

  Alternatively, a cooling dissolution method is also preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

  Next, this cellulose ester solution is filtered using a suitable filter medium such as filter paper. As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters and the like. However, if the absolute filtration accuracy is too small, there is a problem that the filter medium is likely to be clogged. For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with 0.001 to 0.008 mm is more preferable, and a filter medium with 0.003 to 0.006 mm is still more preferable.

  There are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, plastic filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel do not drop off fibers. preferable. It is preferable to remove and reduce impurities, particularly bright spot foreign matter, contained in the raw material cellulose ester by filtration.

A bright spot foreign material is when two polarizing plates are placed in a crossed Nicol state, a cellulose ester film is placed between them, light is applied from the side of one polarizing plate, and observed from the side of the other polarizing plate. It is a point (foreign matter) where light from the opposite side appears to leak, and the number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm ² or less. More preferably, it is 100 pieces / cm < ² > or less, More preferably, it is 50 pieces / m < ² > or less, More preferably, it is 0-10 pieces / cm < ² > or less. Further, it is preferable that the number of bright spots of 0.01 mm or less is small.

  The dope can be filtered by a normal method, but the method of filtering while heating at a temperature not lower than the boiling point of the solvent at normal pressure and in a range where the solvent does not boil under pressure is the filtration pressure before and after filtration. The increase in the difference (referred to as differential pressure) is small and preferable. A preferred temperature is 45 to 120 ° C, more preferably 45 to 70 ° C, and still more preferably 45 to 55 ° C.

  A smaller filtration pressure is preferred. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

  Here, the dope casting will be described.

  The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support. The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is set to −50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferable because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate. The preferable support temperature is appropriately determined at 0 to 100 ° C, and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short. When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. . In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

  In order for the cellulose ester film to exhibit good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. Especially preferably, it is 20-30 mass% or 70-120 mass%. The temperature at the peeling position on the metal support is preferably −50 to 40 ° C., more preferably 10 to 40 ° C., and most preferably 15 to 30 ° C.

  In the present invention, the amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  Moreover, in the drying process of the cellulose ester film, the web is peeled off from the metal support, further dried, and dried until the residual solvent amount is 0.5% by mass or less.

  In the film drying process, generally, a roll drying method (a method in which a plurality of rolls arranged on the upper and lower sides are alternately passed through and dried) or a method of drying while transporting the web by a tenter method is adopted.

  When peeling from the metal support, the web is stretched in the longitudinal direction due to the peeling tension and the subsequent conveying tension. Therefore, in the present invention, when peeling the web from the casting support, the peeling and conveying tensions are reduced as much as possible. It is preferable to carry out in the state. Specifically, for example, it is effective to set it to 50 to 170 N / m or less. At that time, it is preferable to apply a cold air of 20 ° C. or less to fix the web rapidly.

  Next, the dried film can be used as an unpolymer film to be stretched at a desired angle by the above-described oblique stretching tenter according to the present invention to obtain a polymer film.

<Functional layer>
The polymer film of the present invention can be provided with functional layers such as a hard coat layer, an antistatic layer, a back coat layer, an antireflection layer, a slippery layer, an adhesive layer, an antiglare layer, and a barrier layer.

<Hard coat layer>
The polymer film of the present invention may be provided with a hard coat layer. The hard coat layer preferably contains an actinic radiation curable resin, and is a layer mainly composed of a resin that cures through a crosslinking reaction upon irradiation with actinic rays (also referred to as active energy rays) such as ultraviolet rays and electron beams.

  As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and an actinic radiation curable resin layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams. The

  Typical examples of the actinic radiation curable resin include an ultraviolet curable resin and an electron beam curable resin, but the resin that is cured by ultraviolet irradiation is excellent in mechanical film strength (abrasion resistance, pencil hardness). preferable.

  As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, ultraviolet curable acrylate resins are preferred.

  Or it is preferable to contain a photoinitiator in a docoat layer in order to accelerate | stimulate hardening of actinic radiation curable resin. The amount of the photopolymerization initiator is preferably contained in a mass ratio of photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100.

  Specific examples of the photopolymerization initiator include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.

  Alternatively, the docoat layer preferably contains fine particles of an inorganic compound or an organic compound.

  As inorganic fine particles, silicon oxide, titanium oxide, aluminum oxide, tin oxide, indium oxide, ITO, zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated silicic acid Mention may be made of calcium, aluminum silicate, magnesium silicate and calcium phosphate. In particular, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.

  As organic particles, polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, melamine resin powder, A polyolefin resin powder, a polyester resin powder, a polyamide resin powder, a polyimide resin powder, a polyfluoroethylene resin powder, or the like can be added.

  The average particle size of these fine particle powders is not particularly limited, but is preferably 0.01 to 5 μm, and more preferably 0.01 to 1.0 μm. Moreover, you may contain 2 or more types of microparticles | fine-particles from which a particle size differs. The average particle diameter of the fine particles can be measured by, for example, a laser diffraction particle size distribution measuring device.

  The ratio of the ultraviolet curable resin composition and the fine particles is desirably 10 to 400 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the resin composition.

  These hard coat layers are coated using a known method such as a gravure coater, dip coater, reverse coater, wire bar coater, die coater, ink jet method, and the like. And can be formed by UV curing.

  The dry thickness of the hard coat layer is an average film thickness of 0.1 to 30 μm, preferably 1 to 20 μm, particularly preferably 6 to 15 μm.

  As a light source for UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 200 mJ / cm ² .

<Back coat layer>
In the polymer film of the present invention, a back coat layer may be provided on the surface of the film opposite to the side on which the hard coat layer is provided in order to prevent curling and sticking.

  As particles added to the back coat layer, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, tin oxide, and oxidation. Mention may be made of indium, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate.

  The particles contained in the backcoat layer are preferably 0.1 to 50% by mass with respect to the binder. When the back coat layer is provided, the increase in haze is preferably 1.5% or less, more preferably 0.5% or less, and particularly preferably 0.1% or less.

  As the binder, a cellulose ester resin such as diacetylcellulose is preferable.

<Antireflection layer>
The polymer film of the present invention can be used as an antireflection film having an antireflection function for external light by coating an antireflection layer on the hard coat layer.

  The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is preferably composed of a low refractive index layer having a refractive index lower than that of the support, or a combination of a high refractive index layer having a refractive index higher than that of the support and a low refractive index layer. Particularly preferably, it is an antireflection layer composed of three or more refractive index layers. Three layers having different refractive indexes from the support side are divided into medium refractive index layers (high refractive index layers having a higher refractive index than the support). Are preferably laminated in the order of a layer having a lower refractive index) / a high refractive index layer / a low refractive index layer. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used.

  As the layer structure of the antireflection film, the following structure is conceivable, but is not limited thereto. Here, / indicates that the layers are arranged in layers.

Polymer film / Clear hard coat layer / Low refractive index layer Polymer film / Clear hard coat layer / High refractive index layer / Low refractive index layer Polymer film / Clear hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index Layer Polymer film / Anti-glare hard coat layer / Low refractive index layer Polymer film / Anti-glare hard coat layer / High refractive index layer / Low refractive index layer Polymer film / Anti-glare hard coat layer / Medium refractive index layer / High Refractive index layer / low refractive index layer The low refractive index layer essential for the antireflection film preferably contains silica-based fine particles, and the refractive index thereof is lower than the refractive index of the support. It is preferably lower than the refractive index and in the range of 1.30 to 1.45 when measured at 23 ° C. and wavelength of 550 nm.

  The film thickness of the low refractive index layer is preferably 5 nm to 0.5 μm, more preferably 10 nm to 0.3 μm, and most preferably 30 nm to 0.2 μm.

  The composition for forming a low refractive index layer preferably contains at least one kind of particles having an outer shell layer and porous or hollow inside as silica-based fine particles. In particular, the particles having the outer shell layer and porous or hollow inside are preferably hollow silica-based fine particles.

  The composition for forming a low refractive index layer may contain an organosilicon compound represented by the following general formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.

General formula (OSi-1): Si (OR) ₄
In the organic silicon compound represented by the general formula, R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

  In addition, a silane coupling agent, a curing agent, a surfactant and the like may be added as necessary.

<Λ / 4 plate and polarizing plate>
The polymer film of the present invention can be used for a polarizing plate in various modes according to various purposes. In the present invention, it is preferably used as a λ / 4 plate having the following characteristics.

  In the present application, the “λ / 4 plate” refers to a plate having a function of converting linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light). The λ / 4 plate is designed such that the in-plane retardation value Ro is about 1/4 with respect to a predetermined wavelength of light (usually in the visible light region).

  That is, the λ / 4 plate has a retardation of approximately ¼ of the wavelength in the visible light wavelength range in order to obtain almost perfect circularly polarized light in the visible light wavelength range. It is preferable that

  “A phase difference of approximately ¼ in the wavelength range of visible light” means an in-plane phase difference represented by the following formula (i) measured at a wavelength of 450 nm. The value Ro (450) and the in-plane retardation value Ro (590) measured at a wavelength of 590 nm preferably satisfy 1 <Ro (590) / Ro (450) ≦ 1.6. Furthermore, in order to function effectively as a λ / 4 plate, Ro (450) is in the range of 100 to 125 nm, and the phase difference value Ro (550) measured at a wavelength of 550 nm is in the range of 110 to 170 nm. It is more preferable that Ro (590) is a retardation film in the range of 130 to 152 nm.

Formula _{(i): Ro = (n} x -n y) × d
Formula (ii): Rt = {(n _x + n _y ) / 2−n _z } × d
_{Wherein, n x,} n _y is, 23 ℃ · 55% RH, 450nm, say 550 nm, the maximum of the refractive index in the plane of the refractive index _{n x} (film in each of the 590 nm, also the slow axis direction of the refractive index. ), Ny (refractive index in the direction perpendicular to the slow axis in the film plane), and d is the thickness (nm) of the film.

  The in-plane retardation value Ro and the thickness direction retardation value Rt can be measured using an automatic birefringence meter. Using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments), a phase difference value at each wavelength is measured in an environment of 23 ° C. and 55% RH. In this report, unless otherwise stated, Ro and Rt indicate average values obtained by measuring a plurality of arbitrary points.

  The retardation value can be adjusted by adjusting and controlling the components, composition, stretching conditions, etc. of the polymer film. It can also be done by adding a retardation adjusting agent.

Further, the angle θ ₁ formed by the in-plane slow axis (b) after stretching and the film width direction (a) is also measured using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments). It can be measured by setting the hand direction (a) to 0 °. The sign of θ ₁ is the in-plane slow axis of the film when the film is viewed so that the small turn (SD) side is on the left, the large turn (LD) side is on the right, and the transport direction is up, as shown in FIG. The case where b is present in the upper left-lower right direction is defined as plus, and the case where it is present in the upper right-lower left direction is defined as minus (hereinafter, when no sign is described, it is defined as plus). In the λ / 4 plate of the present invention, θ ₁ is preferably 40 ° ≦ θ ₁ ≦ 50 °, more preferably 44 ° ≦ θ ₁ ≦ 46 °.

  A circularly polarizing plate is obtained by laminating so that the angle between the slow axis of the λ / 4 plate and the transmission axis of the polarizer described later is substantially 45 °. “Substantially 45 °” means 40 to 50 °. The angle between the slow axis in the plane of the λ / 4 plate and the transmission axis of the polarizer is preferably 41 to 49 °, more preferably 42 to 48 °, and 43 to 47 °. Is more preferable, and it is most preferable that it is 44-46 degrees.

  The polarizing plate according to the present invention uses a stretched polyvinyl alcohol doped with iodine or a dichroic dye as a polarizer, and the polymer film of the present invention is a λ / 4 plate / polarizer / optical film ( Y) can be bonded and manufactured. The λ / 4 plate is bonded to the viewing side.

  The optical film (Y) is preferably a polymer film, preferably manufactured easily, optically uniform, and optically transparent. Any of these may be used, for example, cellulose ester film, polyester film, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyethylene terephthalate, polyethylene naphthalate. Polyester film such as polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose acetate butyrate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, polycarbonate film, norbornene resin Film, polymethylpentene film, polyetherketone film, Polyether ketone imide film, a polyamide film, a fluoropolymer film, a nylon film, a cycloolefin polymer film, polyvinyl acetal polymer film, there may be mentioned polymethyl methacrylate film, or an acrylic film or the like, but are not limited to.

  In the case of a cellulose ester film, the cellulose acetate, plasticizer, UV absorber, antioxidant, retardation adjusting agent, matting agent, deterioration inhibitor, peeling aid, surfactant, etc. used in the polymer film described above are used. It can be preferably used.

  The optical film (Y) bonded to the surface opposite to the surface on which the λ / 4 plate is bonded to the polarizer has retardation values Ro and Rt defined by the above formulas of 20 to 150 nm, respectively. It is preferable that the optical film is 70 to 400 nm, or 0 nm ≦ Ro ≦ 2 nm and −15 nm ≦ Rt ≦ 15 nm.

  As the optical film (Y), for example, a method of supporting a discotic liquid crystalline compound, which is a compound having negative uniaxiality, on a support (for example, see JP-A-7-325221), a positive optical difference. A method in which a nematic polymer liquid crystal compound having a directivity is subjected to hybrid alignment in which the pretilt angle of liquid crystal molecules changes in the depth direction is supported on a support (see, for example, JP-A-10-186356). ), A nematic liquid crystal compound having a positive optical anisotropy is formed on a support in a two-layer structure, and the orientation direction of each layer is set to approximately 90 °, thereby pseudo-uniaxially similar optical characteristics. In place of an optical film provided with an optically anisotropic layer on a support or a conventional TAC film (for example, see JP-A-8-15681). An optical film having a retardation film function by stretching a cellulose derivative film and then saponifying the cellulose derivative film and laminating a PVA polarizer (see, for example, JP-A-2003-270442). Examples of the optical compensation film include a method of adding a retardation adjusting agent to a cellulose ester film to obtain a retardation film (see, for example, JP-A Nos. 2000-275434 and 2003-344655). It is not limited.

  For example, as a commercially available cellulose ester film, Konica Minoltak KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC12UR, KC16UR, KC4UE, KC4UE, KC4FR, KC4FR-1 And the like) are also preferably used.

  The film thickness of the polarizer is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

  The polarizing plate can be produced by a general method. The λ / 4 plate according to the present invention subjected to alkali saponification treatment is bonded to at least one surface of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Is preferred. It is preferable to paste the optical film on the other surface.

  The polarizing plate can be constructed by further bonding a protective film on one surface of the polarizing plate and a separate film on the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.

<Liquid crystal display device>
By using the polarizing plate according to the present invention as a liquid crystal display device bonded to the viewing side surface of the liquid crystal cell, the liquid crystal display device according to the present invention can be produced.

  The polarizing plate according to the present invention is a reflective type, transmissive type, transflective type LCD, super twisted nematic (STN) mode, twisted nematic (TN) mode, in-plane switching (IPS) mode, vertical alignment (VA) mode, It is preferably used for a liquid crystal display device of an optically aligned birefringence (OCB) mode and a hybrid aligned nematic (HAN) mode.

<Stereoscopic image display device>
The λ / 4 plate of the present invention can be used in various modes in a stereoscopic image display device. For example, a stereoscopic image display device including a liquid crystal display device and stereoscopic image viewing glasses, wherein the stereoscopic image viewing glasses include (1) a λ / 4 plate, a liquid crystal cell, and a polarizer in this order. Or (2) use in a stereoscopic image display device having a configuration in which the λ / 4 plate, the polarizer, the liquid crystal cell, and the polarizer are provided in this order, and are stereoscopic image viewing glasses. it can.

  FIG. 4 shows a schematic diagram of the stereoscopic image display apparatus of the above-described aspect (1) (system with one polarizing plate of glasses). Further, FIG. 5 shows a schematic diagram of the above-described aspect (2) (system in which the glasses have two polarizing plates).

  In any case, the front polarizing plate of the liquid crystal display device is provided with a λ / 4 plate, a polarizer, and an optical film in this order, and the λ / 4 plate is disposed on the viewing side. It is configured. In the present invention, the above aspect and configuration can reduce crosstalk or luminance reduction and color change when tilting the head when viewing stereoscopic (3D) video images, and maintain excellent visibility in the usage environment. Therefore, a stereoscopic image display device with higher durability against the use environment can be obtained.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Production Example 1>
<Preparation of roll-shaped raw film 1>
(Preparation of polyester A)
In a nitrogen atmosphere, 4.85 g of dimethyl terephthalate, 4.4 g of 1,2-propylene glycol, 6.8 g of p-toluic acid, and 10 mg of tetraisopropyl titanate were mixed and stirred at 140 ° C. for 2 hours. Stirring was carried out at ° C for 16 hours. Next, the temperature was lowered to 170 ° C., and unreacted 1,2-propylene glycol was distilled off under reduced pressure to obtain polyester A.

Acid value: 0.1
Number average molecular weight: 490
Dispersity: 1.4
Component content of molecular weight 300-1800: 90%
Hydroxyl (hydroxyl) value: 0.1
Hydroxyl group (hydroxyl group) content: 0.04%
Polyester A has a terminal toluic acid ester because the monocarboxylic acid is used in an amount twice as much as that of the dicarboxylic acid.

<Fine particle dispersion 1>
Fine particles (Aerosil R812 manufactured by Nippon Aerosil Co., Ltd.) 11 parts by weight Ethanol 89 parts by weight The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

<Fine particle addition liquid 1>
The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

Methylene chloride 99 parts by mass Fine particle dispersion 1 5 parts by mass A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. The cellulose ester was added to the pressure dissolution tank containing the solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

<Composition of main dope solution>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose ester (cellulose diacetate: acetyl group substitution degree 2.4, propionyl group 0, total substitution degree 2.4) 100 parts by mass The following sugar ester compound A 7.0 parts by mass Polyester A 2.5 parts by mass TINUVIN 928 (manufactured by BASF Japan) 1.5 parts by mass Particulate additive liquid 1 1 part by mass

  The above was put into a sealed container and dissolved with stirring to prepare a dope solution.

  Next, using an endless belt casting apparatus, the dope solution was uniformly cast on a stainless steel belt support at a temperature of 33 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

  On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film became 75%, and then peeled off from the stainless steel belt support with a peeling tension of 110 N / m.

  The peeled cellulose ester film was stretched 5% in the width direction using a tenter while applying heat at 160 ° C. The residual solvent at the start of stretching was 15%.

  Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m.

  As described above, a roll-shaped raw film 1 having an average dry film thickness of 75 μm was obtained.

  The thickness variation in the longitudinal direction of the obtained raw film 1 was 0.15 μm, and the thickness variation in the width direction was 0.15 μm. When the in-plane retardation at the wavelength of 550 nm and the retardation in the thickness direction were measured by the above-described methods, Ro (550) was 10 nm and Rt (550) was 120 nm.

<Production Example 2>
<Preparation of roll-shaped raw film 2>
A roll-shaped raw film as in Production Example 1 except that the cellulose ester in Production Example 1 was changed to cellulose acetate propionate having an acetyl group substitution degree of 1.5, a propionyl group of 0.9, and a total substitution degree of 2.4. 2 was obtained.

  The obtained raw film 2 had an average dry film thickness of 76 μm, a thickness unevenness in the longitudinal direction of 0.15 μm, and a thickness unevenness in the width direction of 0.15 μm. The in-plane retardation value Ro (550) at a wavelength of 550 nm was 10 nm, and the retardation value Rt (550) in the thickness direction was 118 nm.

<Production Example 3>
(Synthesis of acrylic polymer)
A glass flask equipped with a stirrer, two dropping funnels, a gas introduction tube and a thermometer was charged with 28 g of methyl methacrylate, 12 g of N-vinylpyrrolidone, 2 g of mercaptopropionic acid as a chain transfer agent and 30 g of toluene, and the temperature was raised to 90 ° C. did. Thereafter, from one dropping funnel, 60 g of a mixed solution of 42 g of methyl methacrylate and 18 g of N-vinylpyrrolidone was dropped over 3 hours, and simultaneously 0.4 g of azobisisobutyronitrile dissolved in 14 g of toluene from the other funnel. Was added dropwise over 3 hours. Thereafter, 0.6 g of azobisisobutyronitrile dissolved in 56 g of toluene was added dropwise over 2 hours, and the reaction was further continued for 2 hours to obtain a polymer. The obtained polymer was solid at room temperature. Next, polymers having different molecular weights were prepared by changing the addition amount of the chain transfer agent mercaptopropionic acid and the addition rate of azobisisobutyronitrile. The weight average molecular weight of the polymer was 10,000 by the following measurement method.

(Weight average molecular weight)
The weight average molecular weight of the polymer was determined by GPC polystyrene conversion described above.

<Production Example 4>
<Preparation of roll-shaped raw film 3>
(Preparation of dope solution)
Cellulose ester (cellulose acetate propionate: acetyl group substitution degree 0.05, propionyl group 1.89, total substitution degree 1.94: vacuum dried at 60 ° C. for 24 hours)
70 parts by mass Acrylic polymer prepared in Production Example 3 30 parts by mass TINUVIN 928 (manufactured by BASF Japan) 1.5 parts by mass Silicon oxide fine particles (Aerosil R972V (manufactured by Nippon Aerosil Co., Ltd.))
0.1 parts by weight Methylene chloride 300 parts by weight Ethanol 40 parts by weight A dope solution having the above composition was prepared and then filtered by Finemet NF manufactured by Nippon Seisen Co., Ltd. Were cast uniformly on a stainless steel band support.

  With the stainless steel band support, the solvent was evaporated until the amount of residual solvent reached 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m. The peeled cellulose ester web was evaporated at 35 ° C., slit to 1.6 m width, and then dried at a drying temperature of 135 ° C. while stretching 1.05 times in the width direction with a tenter. At this time, the residual solvent amount when starting stretching with a tenter was 10%. After stretching with a tenter, relaxation was performed at 130 ° C. for 5 minutes, and then drying was completed while transporting a drying zone at 120 ° C. and 130 ° C. with many rolls, slitting to a width of 1.5 m, and a width of 10 mm at both ends of the film. A knurling process having a height of 5 μm was performed, and the film was wound around a core having an inner diameter of 6 inches with an initial tension of 220 N / m and a final tension of 110 N / m to obtain a roll-shaped raw film 3. The draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.01. An original film 3 having an average dry film thickness of 76 μm and a winding number of 4000 m was obtained.

  The thickness variation in the longitudinal direction of the obtained raw film 3 was 0.15 μm, and the thickness variation in the width direction was 0.15 μm. The in-plane retardation value Ro (550) at a wavelength of 550 nm was 5 nm, and the retardation value Rt (550) in the thickness direction was 115 nm.

<Production Example 5>
<Preparation of roll-shaped raw film 4>
MMA 7000 g, MHMA 3000 g, and toluene 12000 g were charged into a 30 L reaction kettle equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction pipe, and the temperature was raised to 105 ° C. through nitrogen and refluxed. -While adding 6.0 g of amyl peroxy isononanoate (Lupazole 570, manufactured by Atofina Yoshitomi Co., Ltd.), a solution comprising 12.0 g of t-amyl peroxy isononanoate and 100 g of toluene was dropped over 2 hours. Then, solution polymerization was performed under reflux (about 105 to 110 ° C.), followed by further aging for 4 hours. The polymerization reaction rate was 92.9%, and the MHMA content (mass ratio) in the polymer was 30.2%.

  To the obtained polymer solution, 20 g of an octyl phosphate / dioctyl phosphate mixture (manufactured by Sakai Chemicals, trade name: Phoslex A-8) was added, and cyclization condensation reaction was performed under reflux (about 80 to 105 ° C.) for 2 hours. Then, 4000 g of methyl ethyl ketone was added and diluted. Furthermore, the cyclization condensation reaction was performed for 1.5 hours under pressure in an autoclave using a heating medium at 240 ° C. (gauge pressure was about 2 MPa at maximum).

  Subsequently, the polymer solution obtained by the cyclization condensation reaction was diluted with methyl ethyl ketone, 26.5 g of zinc octylate (Nikka octix zinc 18%, manufactured by Nippon Chemical Industry Co., Ltd.), IRGANOX 1010 as an antioxidant. A solution consisting of 2.2 g (BASF Japan Co., Ltd.) and 2.2 g ADK STAB AO-412S (manufactured by ADEKA Co., Ltd.) and 61.6 g toluene was added at a rate of 20 g / hour, and the barrel temperature was Except having been 250 degreeC, the cyclization condensation reaction and devolatilization were performed in the vent type screw twin-screw extruder like the manufacture example 1, and the transparent pellet was obtained by extrusion.

  When the obtained pellet was measured for dynamic TG, a mass reduction of 0.21% by mass was detected. Moreover, the weight average molecular weight of the pellet was 110000, the melt flow rate was 8.7 g / 10 min, and the glass transition temperature was 142 ° C.

Subsequently, the pellets were extruded using a single screw extruder having a cylinder diameter of 20 mm under the following conditions to produce a raw film 4 having an average film thickness of 74 μm.
Cylinder temperature: 280 ° C
Die: Coat hanger type, temperature 290 ° C
Casting: Two rolls with gloss, 1st roll and 2nd roll are both 130 ° C
The thickness variation in the longitudinal direction of the obtained raw film 4 was 0.15 μm, and the thickness variation in the width direction was 0.15 μm. The in-plane retardation value Ro (550) at a wavelength of 550 nm was 5 nm, and the retardation value Rt (550) in the thickness direction was 0 nm.

<Production Example 6>
<Preparation of roll-shaped raw film 5>
A pellet of norbornene resin (ZEONOR1420: glass transition point = 137 ° C., manufactured by Nippon Zeon Co., Ltd.) was dried at 100 ° C. for 5 hours. The pellets are supplied to an extruder with a cylinder diameter of 20 mm, melted in the extruder, passed through a polymer pipe and a polymer filter, extruded from a T die onto a casting drum, cooled, and cooled to a thickness of 75 μm. Five films were obtained. The in-plane retardation value Ro (550) at a wavelength of 550 nm was 5 nm, and the retardation value Rt (550) in the thickness direction was 1 nm.

<Example 1>
The raw film 1 was stretched using the offline stretching apparatus 1 described in FIG.

  First, the raw film 1 is attached to the roll mounting shaft 10 of the film delivery device 13 and set at the delivery position, and then wound through the accumulator 4, the tenter 5, the ear clip device 6, the thermal relaxation unit 7, and the cooling unit 8. It conveyed so that it might be wound up in roll shape by the part 9. FIG. In the accumulator part 4, a loop was made sufficiently. In the tenter part, the film was stretched at 175 ° C. and a stretch ratio of 1.5 times.

The average thickness of the obtained retardation film is 50 μm, the in-plane retardation value Ro (550) at a wavelength of 550 nm is 140 nm, and the angle θ ₁ formed by the in-plane slow axis b and the film width direction a is 45 °. Met.

Attach a new roll of raw film 1 to the mounting shaft 10 at the core replacement position, and after the roll film at the feed position has run out, rotate the turret arm 180 ° to feed the new roll film 1 at the feed position. To the joining area 3. In the joining area 3, a spot type ultrasonic welding machine is used, and the ultrasonic welding machine is run so that the angle (φ ₀ ) between the width direction (a) and the joining line (f) is −45 °, and joining is performed. did. The leading edge of the preceding film after joining and the leading edge of the succeeding film were cut so as to be parallel to the joining line. Both ends of the width that are chucked by the gripping tool in the subsequent tenter unit 5 were processed twice with an ultrasonic welding machine along the same joining line, so that the total thickness was 94 μm. Moreover, the molten resin which protruded from the width | variety both ends was cut | disconnected with the laser cutter.

  During the joining operation, the film stored in the accumulator unit 4 was sent to the tenter unit 5, so the tenter unit 5 did not stop. The bonded original film 1 was conveyed to the tenter unit 5 through the accumulator unit 4.

  In the tenter portion 5, the joint portion was also stretched in the oblique direction like the peripheral portion, and failure such as breakage did not occur.

Angle phi ₁ between the bonding lines after stretching (f) and the width direction (a) was 1 °.

<Example 2>
Using the raw film 2, continuous oblique stretching was performed in the same manner as in Example 1. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 135 nm, and θ ₁ was 45 °. In the joining area 3, the same ultrasonic welder as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −43 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 3 °.

<Example 3>
The original fabric film 3 was used for oblique stretching continuously in the same manner as in Example 1 except that the stretching temperature was changed to 145 ° C. The average film thickness after stretching was 51 μm, the in-plane retardation value Ro (550) was 140 nm, and θ ₁ was 46 °. In the joining area 3, the same ultrasonic welder as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −45 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 2 °.

<Example 4>
The original fabric film 4 was used, and oblique stretching was continuously performed in the same manner as in Example 1 except that the stretching temperature was changed to 155 ° C. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 140 nm, and θ ₁ was 45 °. In the joining area 3, the same ultrasonic welding machine as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −48 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was -4 °.

<Example 5>
Diagonal stretching was performed continuously in the same manner as in Example 1 except that the stretching temperature was changed to 145 ° C. using the raw fabric film 5. The average film thickness after stretching was 51 μm, the in-plane retardation value Ro (550) was 140 nm, and θ ₁ was 46 °. In the joining area 3, the same ultrasonic welder as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −46 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 2 °.

<Example 6>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 138 nm, and θ ₁ was 41 °. In the joining area 3, the same ultrasonic welding machine as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −48 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was -5 °.

<Example 7>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 51 μm, the in-plane retardation value Ro (550) was 141 nm, and θ ₁ was 50 °. In the joining area 3, the same ultrasonic welder as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −42 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 5 °.

<< Evaluation >>
The long lambda / 4 board with a junction part of Examples 1-7 was evaluated as follows.

<In-plane orientation angle disorder>
The center of the width (point A ₃ , see FIG. 6) at a position 2 m away from the joining line in the transport direction, and the point A ₄ that is 10 cm away from the point A ₃ on the large turn side (LD side), the point A that is 20 cm away _5, maneuverability side from point _{a 3} in (SD side) point away 10cm to _a 2, 20 cm distant point _{a 1,} the angle between the plane slow axis width direction _{a θ 1 a 3, θ 1} a ₄ , θ ₁ A ₅ , θ ₁ A ₂ , θ ₁ A ₁ were measured in an environment of 23 ° C. and 55% RH using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments). The standard deviation σθ was determined and evaluated according to the following criteria. The results are shown in Table 1.
◎: standard deviation Shigumashita ₁ is a 2 ° less ○: × standard deviation Shigumashita ₁ is within 4 °: If the standard deviation Shigumashita ₁ is 4 ° larger than the standard deviation Shigumashita ₁ is within 4 °, the display device of This is a level where there is no practical problem.

<Display device>
The λ / 4 plate obtained in Examples 1 to 7 was converted into a polarizing plate in the following manner to produce a stereoscopic image display device.

<Preparation of optical film 6>
(Fine particle dispersion 1)
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by weight Ethanol 89 parts by weight The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

(Fine particle addition liquid 1)
The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

Methylene chloride 99 parts by mass Fine particle dispersion 1 5 parts by mass A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate was added to a pressurized dissolution tank containing a solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

(Main dope composition)
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose acetate having an acetyl group substitution degree of 2.4 100 parts by mass The following sugar ester compound T 10.0 parts by mass Polyester P 2.5 parts by mass UV absorber (TINUVIN 928 (BASF Japan ( Co., Ltd.))) 2.3 parts by mass Particulate Additive Solution 1

  The composition was put into a closed container and dissolved with stirring to prepare a dope solution. Next, an endless belt casting apparatus was used to uniformly cast the dope solution on a stainless steel belt support at a temperature of 33 ° C. and a width of 2000 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

  On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film was 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.

  Thereafter, the film is stretched 1.4 times in the width direction by a tenter set at 170 ° C., then dried by being transported for 30 minutes in a drying zone set at 130 ° C., and has a width of 2 m and a width of 1 cm at the end. An optical film 6 with a film thickness of 40 μm having a knurling height of 8 μm was prepared and wound up at 5000 m.

  The retardation values Ro (550) and Rt (550) of the optical film 6 were 50 nm and 130 nm, respectively.

(Synthesis of polyester P)
In a nitrogen atmosphere, 4.85 g of dimethyl terephthalate, 4.4 g of 1,2-propylene glycol, 6.8 g of p-toluic acid, and 10 mg of tetraisopropyl titanate were mixed and stirred at 140 ° C. for 2 hours. Stirring was carried out at ° C for 16 hours. Next, the temperature was lowered to 170 ° C., and unreacted 1,2-propylene glycol was distilled off under reduced pressure to obtain polyester P.

Acid value: 0.1
Number average molecular weight: 490
Dispersity: 1.4
Component content of molecular weight 300-1800: 90%
Hydroxyl (hydroxyl) value: 0.1
Hydroxyl group (hydroxyl group) content: 0.04%
<Preparation of polarizing plate>
A 120 μm thick polyvinyl alcohol film was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times) to obtain a long roll film. This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a long roll-shaped polarizer.

  Next, according to the following steps 1 to 5, a long roll-shaped polarizer, the λ / 4 plate obtained in Examples 1 to 7, and the optical film 6 are bonded to the back side by a roll-to-roll, and a polarizing plate. Was made. The λ / 4 plate used was a roll formed by cutting the joint at a distance of 1 m from the joint line in the transport direction and in the direction opposite to the transport.

  Step 1: Dipped in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to obtain a λ / 4 plate having a saponified side to be bonded to a polarizer.

  Process 2: The said polarizer was immersed in the polyvinyl alcohol adhesive tank of 2 mass% of solid content for 1-2 seconds.

  Step 3: Excess adhesive adhered to the polarizer in Step 2 was gently wiped off and placed on the λ / 4 plate treated in Step 1.

Step 4: The λ / 4 plate, the polarizer, and the optical film 6 laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm ² and a conveyance speed of about 2 m / min.

  Step 5: A sample obtained by bonding the polarizer, the λ / 4 plate, and the optical film 6 produced in Step 4 in a drier at 80 ° C. by roll-to-roll was dried for 2 minutes to produce a polarizing plate.

  In the above polarizing plate, the in-plane slow axis of the λ / 4 plate and the absorption axis of the polarizer were bonded with an inclination of 45 °.

<Production of liquid crystal display device>
Remove the pre-bonded front plate of Sony 60-type display BRAVIA LX900, remove the filler between the front plate and the polarizing plate on the front of the panel, and peel off the pre-bonded front polarizing plate of the panel And the polarizing plate produced using the above-mentioned (lambda) / 4 board of Examples 1-7 was bonded on the front surface of the glass surface of a liquid crystal cell, respectively.

  The polarizing plate used for the evaluation was cut out from the roll-shaped polarizing plate prepared as described above. At that time, a place 1 m from the end of the λ / 4 plate (that is, before cutting the bonding portion, from the bonding line). It was cut out and used so that a place 2 m away) came to the center of the polarizing plate.

  When bonding to the glass surface of the liquid crystal cell, the direction of bonding of the polarizing plate is such that the λ / 4 plate is on the viewing side, and the absorption axis is in the same direction as the polarizing plate previously bonded. It bonded so that it might face, and each produced the liquid crystal display devices 1-7 corresponding to Examples 1-7, respectively.

<3D glasses>
The λ / 4 plate produced in Example 1 was bonded to the panel side of the 3D glasses TDG-BR100 made by SONY (the side far from the eyes).

<< Evaluation >>
The display devices manufactured using the λ / 4 plates manufactured in Examples 1 to 7 as described above were evaluated as follows.

<Evaluation of crosstalk when tilting head when viewing stereoscopic (3D) image>
About the produced liquid crystal display device, the following reference | standard evaluated the crosstalk at the time of tilting the neck at the time of stereoscopic (3D) image viewing.

  Turn on the backlight of the liquid crystal display device in an environment of 23 ° C. and 55% RH, wear glasses for viewing stereoscopic images, and watch 3D images with the glasses tilted at 25 °, Crosstalk was evaluated according to the following criteria.

A: There is no crosstalk. O: Weak crosstalk is visible. X: Crosstalk is clearly visible. The above evaluation results are shown in Table 1.

  In the stereoscopic image display devices provided with the λ / 4 plates of Examples 1 to 7, there was no occurrence of crosstalk when tilting the neck when viewing stereoscopic (3D) images, and the visibility was excellent.

<Comparative Example 1>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 51 μm, the in-plane retardation value Ro (550) was 140 nm, and θ ₁ was 44 °.

In the joining area 3, using the same ultrasonic welder as in Example 1, the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −18 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 25 °.

<Comparative example 2>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 142 nm, and θ ₁ was 45 °. In the joining area 3, the same ultrasonic welding machine as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −71 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was -24 °.

<< Evaluation >>
In the same manner as in Examples 1 to 7, the in-plane orientation angle disorder of the films prepared in Comparative Examples 1 and 2 was evaluated.

  In Comparative Examples 1 and 2, the in-plane orientation angle disorder was large.

  Further, in the same manner as in Examples 1 to 7, the λ / 4 plates of Comparative Example 1 and Comparative Example 2 were converted into polarizing plates to produce a stereoscopic image display device. When the crosstalk when the head was tilted when viewing a stereoscopic (3D) image was evaluated based on the same criteria as in Examples 1 to 7, the crosstalk was clearly observed when the films prepared in Comparative Examples 1 and 2 were provided. And a clear stereoscopic image could not be seen.

  The results are shown in Table 2.

<Example 8>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 141 nm, and θ ₁ was 46 °. In the joining area 3, using the same ultrasonic welding machine as in Example 1, the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −30 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 1 °.

<Example 9>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 140 nm, and θ ₁ was 46 °. In the joining area 3, the same ultrasonic welding machine as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −55 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was -4 °.

<Example 10>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 141 nm, and θ ₁ was 45 °. In the joining area 3, using the same ultrasonic welder as in Example 1, the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −44 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 8 °.

<Example 11>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 50 μm, the in-plane retardation value Ro (550) was 140 nm, and θ ₁ was 46 °. In the joining area 3, the same ultrasonic welding machine as in Example 1 was used, and the joining line (f) and the film width direction (a) were joined so that the angle (φ ₀ ) was −48 °. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was -9 °.

<Example 12>
Using the raw film 1, the film was continuously obliquely stretched in the same manner as in Example 1 at a stretching temperature of 175 ° C. The average film thickness after stretching was 51 μm, the in-plane retardation value Ro (550) was 139 nm, and θ ₁ was 44 °. In the joining area 3, it joined so that the angle ((phi) ₀ ) which a joining line (f) and a film width direction (a) make may be -44 degrees using the heat sealer. Angle phi ₁ of the joint line after stretching (f) and the width direction (a) was 4 °.

<< Evaluation >>
In the same manner as in Examples 1 to 7, the in-plane orientation angle disorder of the films produced in Examples 8 to 12 was evaluated.

  In any of the λ / 4 plates of Examples 8 to 12, the in-plane orientation angle disorder was excellent.

  In addition, in the same manner as in Examples 1 to 7, the λ / 4 plates of Examples 8 to 12 were converted into polarizing plates to produce a stereoscopic image display device. Evaluation of crosstalk when tilting the head when viewing a stereoscopic (3D) image on the same basis as in Examples 1-7 revealed no crosstalk in Examples 8 and 9, but Example 10 and In 11, a weak cross-roke was seen.

  The results are shown in Table 3.

DESCRIPTION OF SYMBOLS 1 Offline drawing apparatus 2 Supply part 3 Joining area 4 Accumulation part (accumulator part)
DESCRIPTION OF SYMBOLS 5 Tenter part 6 Ear-cutting device 7 Heat relaxation part 8 Cooling part 9 Winding part 10 Mounting shaft 11 Film roll 12 Turret arm 13 Film delivery apparatus 14 Tenter 15-1 LD side film grip start point 15-2 SD side film grip start point 16-1 LD side film gripping end point 16-2 SD side film gripping end point 17-1 LD side film gripping means trajectory 17-2 SD side film gripping means trajectory 18 Film feed direction 19-1 Tenter entrance side guide roll 19-2 Tenter outlet side guide roll a Film width direction b In-plane slow axis c Film transport direction d Leading film e Trailing film f Joining line g Joining part φ ₀ Joining line (f) before stretching and film width direction of the joint line after the angle phi ₁ stretching (a) (f) and the film width direction (a) Roundabout side A liquid crystal shutter glasses maneuverability side LD oblique stretching device of the in-plane slow axis of the post to the angle theta ₁ stretching (b) and the angle SD oblique stretching device of the film width direction (a) A1, A4 polarizer A2 Liquid crystal cell A3 λ / 4 plate B Liquid crystal display device (for example, television (TV))
C polarizing plate C1 λ / 4 plate C2 polarizer C3 optical film C4 polarizer protective film D liquid crystal cell E polarizing plate F backlight

Claims (6)

  (1) a joining step of superimposing and joining a leading end portion of a succeeding polymer film on a trailing end portion of a preceding polymer film, and (2) while continuously transporting the joined polymer film, the polymer A stretching process in which the film is heated and both ends are supported by a plurality of gripping tools and stretched in an oblique direction at an angle that is in the range of 40 to 50 ° with the width direction of the polymer film; 3) A method for producing a long polymer film comprising a thermal relaxation step of performing heat treatment for stress relaxation while continuously transporting the stretched polymer film, the rear end of the preceding polymer film And the joining line at the joining portion with the leading edge of the film to be followed is joined so as to be substantially parallel (−10 to 10 °) with respect to the width direction after oblique stretching. A method for producing a long polymer film.   The angle formed by the joining line at the joining portion of the leading end portion of the preceding polymer film and the leading end portion of the following polymer film and the film width direction is within a range of −70 to −20 ° before stretching. The manufacturing method of the elongate polymer film of Claim 1 characterized by the above-mentioned.   The long polymer according to claim 1 or 2, wherein a rear end portion of the preceding polymer film and a front end portion of the following polymer film are joined by welding using ultrasonic vibration. A method for producing a film.   A λ / 4 plate produced by the method for producing a long polymer film according to any one of claims 1 to 3, and measured at a wavelength of 550 nm under an environment of 23 ° C and 55% RH. An in-plane retardation value Ro (550) is in a range of 110 to 170 nm, and a λ / 4 plate.   A polarizing plate comprising the λ / 4 plate according to claim 4.   A stereoscopic image display device comprising the λ / 4 plate according to claim 4.

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