JP2010120304A - Norbornene resin film, method of manufacturing norbornene resin film, polarization plate, optical compensation film for liquid crystal display panel, and antireflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a norbornene resin film capable of preventing thermal oxidization deterioration, and capable of leveling a die stripe. <P>SOLUTION: This norbornene resin film is manufactured by co-extruding, from a die 16, a film-like resin 12A comprising a core layer of a resin composition containing, as a main component, the first norbornene resin 12 having 3 cm<SP>3</SP>/10 min. or more to 15 cm<SP>3</SP>/10 min. or less of flow value at 260°C, and an outer layer of a resin composition containing, as a main component, the second norbornene resin 12' having 15 cm<SP>3</SP>/10 min. or more to 45 cm<SP>3</SP>/10 min. or less of flow value at 260°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a norbornene resin film, a norbornene resin film, a polarizing plate, an optical compensation film for a liquid crystal display panel, and an antireflection film.

Cellulose acylate films and saturated norbornene resin films are obtained by melting raw resin pellets with an extruder, discharging the molten resin from a die into a sheet, cooling and solidifying it on a cooling drum, and peeling it. (For example, refer to Patent Document 1). The cellulose acylate film and saturated norbornene resin film are stretched in the longitudinal (longitudinal) direction and transverse (width) direction to develop in-plane retardation (Re) and retardation in the thickness direction (Rth). It is used as a retardation film of a liquid crystal display element to increase the viewing angle.
JP 2000-352620 A

  By the way, norbornene-based resin is easily oxidized and deteriorated by heat and oxygen, and when a film is formed at a high temperature, foreign matter may be generated at the discharge port of the die. This foreign matter causes streaks on the film.

  On the other hand, when the film is formed at a low temperature, the generation of foreign matters can be suppressed, but the leveling of the die lines is not performed, and the dice lines are generated on the film.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a norbornene-based resin film capable of preventing thermal oxidative degradation and leveling of a die line, and a method for producing the same.

To achieve the above object, norbornene resin films coextruded present invention, a resin composition mainly composed of norbornene resin having a flow value of less than 3 cm ^3/10 minutes or more 15cm ^3/10 min at 260 ° C. outer layer comprising a core layer, on at least one surface of the core layer, the resin composition composed mainly of a norbornene resin having a flow value of less than 15cm ^3/10 minutes or more 45cm ^3/10 min at 260 ° C. containing things It is characterized by providing.

  According to the present invention, the flow value of the outer layer at 260 ° C. is made larger than the flow value of the core layer, thereby forming the film at a lower temperature at the die outlet when the outer layer and the core layer are co-extruded. it can. As a result, leveling of the die stripe and prevention of thermal oxidation deterioration of the discharge port can be achieved.

  In the norbornene-based resin film of the present invention, the ratio of the thickness of the core layer to the total thickness of the outer layer is preferably 20: 1 to 1: 1.

  By setting the ratio of the thickness of the core layer to the total thickness of the layers in the range of 20: 1 to 1: 1, it is possible to achieve both improvement of die stripe and film strength.

  The norbornene-based resin film of the present invention is characterized in that, in the above-mentioned invention, the norbornene-based resin film has a die depth or height of 50 nm or less and a surface Ra of 0.05 μm or less.

  Since the depth or height of the norbornene resin film is 50 nm or less and the surface Ra is 0.05 μm or less, the distortion of the image when attached to the polarizing plate is improved and the appearance is excellent. preferable.

  It was measured with a surface shape / roughness measuring instrument (NewView 6000, manufactured by Zygo), and the depth or height of the die stripe was measured by displacement from the average height.

  The norbornene resin film of the present invention is characterized in that, in the above invention, the norbornene resin film has a thickness of 20 to 300 μm.

  The polarizing plate of the present invention is characterized in that at least one layer of the norbornene resin film is laminated.

  The liquid crystal display optical compensation film of the present invention is characterized in that the norbornene resin film is used as a base material.

  The antireflection film of the present invention is characterized in that the norbornene resin film is used as a base material.

To achieve the above object, a manufacturing method of the norbornene resin film of the present invention, first mainly composed of norbornene resin having a flow value of less than 3 cm ^3/10 minutes or more 15cm ^3/10 min at 260 ° C. a step of melting the resin composition, and a step of melting the second resin composition whose main component is a norbornene resin having a flow value of less than 15cm ^3/10 minutes or more 45cm ^3/10 min at 260 ° C., the second A step of co-extruding a film-form norbornene resin having a resin composition of 1 as a core layer and the second resin composition as an outer layer from a discharge port of a die; and the co-extruded film-form norbornene resin And cooling and solidifying.

  According to the present invention, the outer layer and the core layer having a flow value larger than the flow value of the core layer at 260 ° C. can be co-extruded to form a film at a lower die outlet temperature. As a result, leveling of the die stripe and prevention of thermal oxidation deterioration of the discharge port can be achieved.

  In the method for producing a norbornene resin film of the present invention, in the above invention, the oxygen concentration around the discharge port of the die is preferably 10% or less.

  By setting the oxygen concentration around the die discharge port to 10% or less, more preferably 3% or less, oxidation deterioration can be prevented even if the film is formed at a high temperature. It is possible to more effectively prevent oxidative degradation of the material.

  The method for producing a norbornene-based resin film according to the present invention is such that, in the invention, the oxygen concentration around the discharge port is set to 10% or less by blowing an inert gas heated to 100 to 280 ° C. around the discharge port of the die. It is preferable to do.

  In order to reduce the oxygen concentration around the die, it is effective to blow in an inert gas, but if a low temperature inert gas is blown in, the molten film discharged from the die is cooled unevenly and the die exit This is not preferable because the draw between the part and the roll is non-uniform and the thickness accuracy deteriorates. In order to obtain a film with good thickness accuracy, it is preferable to blow in an inert gas heated to 100 ° C. or higher. On the other hand, when an inert gas exceeding 280 ° C. is blown, the temperature of the molten film is excessively increased and the polymer tends to be thermally deteriorated. Therefore, the temperature of the blown gas is preferably 100 to 280 ° C.

  In the method for producing a norbornene-based resin film of the present invention, in the invention, the cooling and solidifying step is preferably performed by a touch roll method.

  According to the present invention, in the production method of norbornene-based resin film by melt film-forming method, it is possible to prevent the generation of foreign matter by preventing oxidation of norbornene-based resin, which is easily deteriorated by heat, and further leveling of dies can be performed. It is possible to provide a high-quality norbornene-based resin film that is excellent as an optical application.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will be described with reference to the following preferred embodiments, but can be modified in many ways without departing from the scope of the present invention, and other embodiments than the present embodiment can be used. be able to. Accordingly, all modifications within the scope of the present invention are included in the claims.

  In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to”.

  The norbornene-based resin film of the present invention is formed by co-extrusion of a core layer and an outer layer having a larger fluid value than the core layer, and when producing the norbornene-based resin film of the present invention, it can be co-extruded For example, an apparatus as shown in FIG. 1 is used.

  As shown in FIG. 1, the manufacturing apparatus 10 includes an extruder 14 that melt-extrudes a first norbornene resin 12, an extruder 14 ′ that melt-extrudes a second norbornene resin 12 ′, and an extruder 14. Gas is applied to both sides of the film-like resin around the connected pipe 30, the pipe 30 ′ connected to the extruder 14 ′, the die 16 connected to the pipe 30 and the pipe 30 ′, and the outlet of the die 16. Supply pipes 32, 34 to be supplied, a plurality of cooling rollers 18, 20, 22 for cooling the high-temperature film-form norbornene resin 12A (hereinafter referred to as film-form resin 12A) discharged from the die 16 in multiple stages, and a cooling roller 18, a touch roll 28 provided adjacent to 18, a peeling roller 24 for peeling the film-like resin 12 </ b> A from the last cooling roller 22, and a winder for winding the cooled film-like resin 12 </ b> A 26.

The resin composition of the first norbornene-based resin 12, in ISO1133 method, as a primary component, a norbornene resin having a flow value of less than ^{3 cm} 3/10 minutes or more 15cm ^3/10 min at 260 ° C.. The resin composition of the second norbornene-based resin 12 'is put ISO1133 method, as a main component a norbornene resin having a flow value of less than 15cm ^3/10 minutes or more 45cm ^3/10 min at 260 ° C. is there. Extruders 14 and 14 ′ for melting and extruding the first norbornene resin 12 and the second norbornene resin 12 ′ are connected to one die 16.

  The die 16 transports the discharge port, two or more pocket portions that separately receive the molten first resin composition and the molten second resin composition, and the molten resin composition in each pocket portion 2. The above-described slits, a merged portion of the molten resin composition connected to each slit, and a discharge port formed continuously to the merged portion are provided.

  Moreover, the die 16 can adjust the supply amount of the material of the molten resin composition or the clearance of the slit of each flow path. Thereby, the thickness of the 1st and 2nd molten resin composition layer merged inside the die | dye 16 can be adjusted according to a request | requirement.

  FIG. 2 shows the configuration of the extruders 14, 14 '. As shown in the figure, a single-shaft screw 50 having a flight 48 attached to a screw shaft 46 is provided in a cylinder 44 of the extruder 14 or 14 ′. The single screw 50 is configured to be rotated by a motor (not shown). A hopper (not shown) is attached to the supply port 52 of the cylinder 44. A norbornene resin is supplied from the hopper into the cylinder 44 through the supply port 52.

  Inside the cylinder 44, in order from the supply port 52 side, a supply unit (region indicated by A) for quantitatively transporting norbornene-based resin supplied from the supply port 52 and a compression unit (region indicated by B) for kneading and compressing norbornene-based resin. ) And a measuring section (area indicated by C) for measuring the kneaded and compressed norbornene-based resin. The norbornene-based resin melted by the extruder 14 is continuously sent from the discharge port 54 to the die.

  The screw compression ratio of the extruder 14 is preferably set to 2.5 to 4.5, and L / D is preferably set to 20 to 70. Here, the screw compression ratio is represented by the volume ratio between the supply unit A and the metering unit C, that is, the volume per unit length of the supply unit A ÷ the volume per unit length of the metering unit C. Is calculated using the outer diameter d1 of the screw shaft 46, the outer diameter d2 of the screw shaft 46 of the measuring section C, the groove diameter a1 of the supplying section A, and the groove diameter a2 of the measuring section C. L / D is the ratio of the cylinder length (L) to the cylinder inner diameter (D) in FIG.

  Next, a method for producing a norbornene-based resin film using the above-described production apparatus 10 will be described with reference to FIG.

  A first norbornene resin 12 is supplied to the extruder 14 from a hopper (not shown), and a second norbornene resin 12 is supplied to the extruder 14 '. The first norbornene-based resin 12 melt-extruded by the extruder 14 is sent to the die 16 via the pipe 30, and the second norbornene-based resin 12 ′ melt-extruded by the extruder 14 ′ is the pipe 30 ′. And sent to the die 16.

  The first norbornene resin 12 and the second norbornene resin 12 ′ supplied to one die 16 are merged inside the die 16 and coextruded from the die 16 as a single film-like resin 12 </ b> A. In the present embodiment, the first norbornene resin 12 serves as the core layer of the norbornene resin film, and the second norbornene resin 12 'serves as the outer layer of the norbornene resin film that covers the core layer. The discharge pressure of the film-like resin 12A discharged from the die 16 is preferably controlled within a fluctuation range within 10%.

  FIG. 3 shows a state in which the film-like resin 12A is coextruded from the discharge port 16A of the die 16. The film-like resin 12A includes a core layer containing the resin composition of the first norbornene resin 12 and an outer layer containing the resin composition of the second norbornene resin 12 ′ formed so as to cover both surfaces of the core layer. ing.

The flow value of the outer layer is set to be larger than the flow value of the core layer. Specifically, the flow value of the core layer, the ISO1133 method is less than ^{3 cm} 3/10 minutes or more 15cm ^3/10 min at 260 ° C., the flow value of the outer layer, in ISO1133 method, 15cm ³ at 260 ° C. / 10 minutes or more 45cm less than ^3/10 min. By making the flow value of the outer layer larger than that of the core layer, the temperature of the discharge port 16A can be lowered to form a film, so that leveling of the die stripe and prevention of thermal oxidation deterioration of the discharge port can be achieved.

  In the norbornene-based resin film, when the core layer is eliminated and only the outer layer having a large flow value is formed, the thermal oxidation deterioration of the discharge port can be prevented, but the mechanical properties are insufficient. In the present invention, by providing a core layer having a small fluid value and an outer layer having a large fluid value, mechanical properties can be satisfied in addition to leveling of the die lines and prevention of thermal oxidation deterioration of the discharge port.

  Next, as shown in FIG. 1, the inert gas heated to 100 to 280 ° C. is supplied from the supply pipes 32 and 34 toward both surfaces of the film-like resin 12 </ b> A coextruded from the discharge port of the die 16. . By setting the oxygen concentration of the inert gas supplied around the discharge port of the die 16 to 10% or less, preferably 3% or less, the oxygen concentration around the discharge port of the die 16 is preferably 10% or less, more preferably. It can be 3% or less. By setting the oxygen concentration around the discharge port of the die 16 to 10% or less, more preferably 3% or less, oxidation deterioration can be prevented even when the film is formed at a high temperature, so that the leveling of the die stripe and the discharge port of the die 16 can be prevented. It is possible to prevent oxidative degradation in the vicinity.

  An inert gas such as nitrogen, helium, neon, or argon can be suitably used as the gas that makes the oxygen concentration around the discharge port of the die 16 10% or less, more preferably 3% or less.

  A control device is connected to the supply pipes 32 and 34, and the flow rate and temperature of the supplied gas can be adjusted as appropriate. The gas flow rate is preferably 0.1 to 2.0 m / sec, and more preferably 0.3 to 1.0 m / sec. The reason is that when the flow rate is too high, the molten film coming out of the die vibrates and the film thickness accuracy tends to decrease. On the other hand, when the flow rate is insufficient, the oxygen concentration inside the die tends to be uneven.

  Regarding the temperature of gas, 100-280 degreeC is preferable and 120-260 degreeC is more preferable. The reason for this is that when the gas temperature is low, the melt film temperature becomes non-uniform, and the thickness accuracy of the film decreases. On the other hand, when the temperature is too high, the polymer tends to be thermally deteriorated, and a tendency to easily generate dice is observed.

Further, the flow rate of the resin discharged from the die 16, it is preferable that the discharge port area per 2.5~30Kg / cm ² of the die 16, and more preferably set to 5 to 20 kg / cm ^2. For reasons in the range of the discharge port area per 2.5~30Kg / cm ² in the case the discharge amount per area is less than 2.5 kg / cm ^2, the residence time of the internal die is too long, thermal degradation There is a tendency to see the generation of gel by the resin. In addition, when it is larger than 30 kg / cm ² , the die swell becomes too large and the eyes and the eyes easily deposit on the end of the discharge port. This is because there is a tendency. Therefore, it can be understood that it is more preferable to set it as 5-20 kg / cm < ² > from the reason mentioned above.

Moreover, it is preferable that the temperature of the discharge port of the die | dye 16 is 255 degrees C or less, and it is more preferable that it is 250 degrees C or less. The reason why the temperature of the discharge port of the die 16 is set to 255 ° C. or less is to suppress thermal deterioration of the polymer attached to the discharge port of the die. Therefore, it can be understood that it is more preferable to set the temperature to 250 ° C. or lower for the reason described above.

  Moreover, it is preferable that the temperature of 12 A of film-form resin discharged from the die | dye 16 is 240-270 degreeC, and it is more preferable that it is 245-265 degreeC. The reason why the temperature of the film-like resin 12A discharged from the die 16 is 240 to 270 ° C. is that when the resin temperature is lower than 240 ° C., the leveling effect of the die stripe is small and the die stripe is likely to deteriorate. Also, the internal pressure of the die increases and the clamshell tends to become larger. In addition, when the resin temperature is higher than 270 ° C., the polymer discharged from the die gels in a short time when it adheres to the lip edge portion, so that the die streak deteriorates rapidly and is not preferable. Therefore, it can be understood that it is more preferable to set the temperature to 245 to 265 ° C. for the reason described above.

  Next, the high-temperature film-like resin 12A discharged from the die 16 is multi-stage cooled by the three cooling rollers 18, 20, and 22 arranged in multi-stages. In this embodiment, the film-like resin 12A is sandwiched between the cooling roller 18 and the adjacent touch roll 28 to be cooled and solidified.

  In the touch roll method, a film surface is formed by placing a touch roll on a cooling roller (cast drum) 18. The touch roll 28 is not usually high in rigidity but preferably has elasticity.

  For this purpose, it is necessary to make the outer cylinder thickness of the roll thinner than that of a normal roll, and the outer wall thickness Z is preferably 0.05 mm to 7.0 mm, more preferably 0.2 mm to 5 mm. 0.0 mm, more preferably 0.3 mm to 3.5 mm. The touch roll may be installed on a metal shaft and a heat medium (fluid) may be passed between them. An elastic layer is provided between the outer cylinder and the metal shaft, and the heat medium (fluid) is filled between the outer cylinders. Can be mentioned.

  The temperature of the touch roll 28 is preferably set to 60 ° C to 160 ° C, more preferably 70 ° C to 150 ° C, and still more preferably 80 ° C to 140 ° C. Such temperature control can be achieved by passing a temperature-controlled liquid or gas through these rolls. Thus, what has a temperature control mechanism inside is more preferable.

  The material of the touch roll 28 is preferably a metal, more preferably stainless steel, and the surface is preferably plated. On the other hand, a rubber roll or a metal roll lined with rubber is not preferable because the rubber surface has irregularities and the thermoplastic film having the surface irregularities cannot be formed.

  The surfaces of the touch roll 28 and the cooling rollers 18, 20, and 22 have an arithmetic average height Ra of 100 nm or less, preferably 50 nm or less, and more preferably 25 nm or less.

  As the multi-stage cooling temperature condition with a plurality of cooling rolls, it is preferable to set the roller surface temperature in order from the upstream side in the film conveyance direction. In this embodiment, it is preferable that the temperature of the cooling roller 18 is set highest and the temperature of the cooling roller 22 is set lowest.

  The cooling and solidification method (casting method) is not limited to the touch roll method of the present embodiment, and other methods such as an air chamber method, a vacuum nozzle method, an electrostatic application method, or an air knife method are preferably used. Can be applied.

  The film-like resin 12A melt-formed as described above is preferably subjected to longitudinal stretching and lateral stretching, and may further be combined with shrinkage treatment. Of these, preferred are those in which transverse stretching is carried out after longitudinal stretching, or a combination of transverse stretching and longitudinal shrinkage treatment. The former is suitable for developing high Rth, and the latter is suitable for developing low Rth.

  When the transverse stretching and the longitudinal shrinkage treatment are performed in combination, the longitudinal shrinkage may be performed during the transverse stretching, may be performed after the transverse stretching, or may be performed both. Further, longitudinal stretching may be combined before or after the transverse stretching or both. Further, after the film-like resin 12A is manufactured by the melt film-forming process, the longitudinal stretching process and the lateral stretching process may be continuously performed without being wound around the winder 26, and then wound.

  In the present invention, longitudinal stretching may be performed alone or in combination with lateral stretching. The longitudinal stretching may be performed either before or after the lateral stretching, but is more preferably performed before the lateral stretching. In addition, the longitudinal stretching may be performed in one stage or may be performed in multiple stages.

  Longitudinal stretching can be achieved by installing two pairs of nip rolls and heating the gap between them so that the peripheral speed of the nip roll on the outlet side is higher than the peripheral speed of the nip roll on the inlet side. Under the present circumstances, the expression of the retardation of the thickness direction can be changed by changing the space | interval (L) between nip rolls, and the film width (W) before extending | stretching. When L / W exceeds 2 and is 50 or less (long span stretching), Rth can be reduced, and when L / W is 0.01 or more and 0.3 or less (short span stretching), Rth can be increased. In the present invention, any of a long span stretching, a short span stretching, and a region between them (intermediate stretching = L / W is more than 0.3 and 2 or less) may be used. Short span stretching is preferred. Further, when aiming at high Rth, it is more preferable to use short span stretching, and when aiming at low Rth, it is distinguished from long span stretching.

  The preferred stretching temperature for these longitudinal stretching is (Tg-10 ° C) to (Tg + 50) ° C, more preferably (Tg-5 ° C) to (Tg + 40) ° C, and more preferably (Tg) to (Tg + 30) ° C. is there. A preferable draw ratio is 2% to 200%, more preferably 4% to 150%, and still more preferably 6% to 100%.

  The transverse stretching can be performed using a tenter. That is, the film is stretched by gripping both ends in the width direction with clips and widening in the lateral direction. At this time, the stretching temperature can be controlled by sending wind at a desired temperature into the tenter. The stretching temperature is preferably Tg-10 ° C to Tg + 60 ° C, more preferably Tg-5 ° C to Tg + 45 ° C, and further preferably Tg to Tg + 30 ° C. A preferable draw ratio is 10% to 250%, more preferably 20% to 200%, and still more preferably 30% to 150%. The draw ratio here is defined by the following formula.

  Stretch ratio (%) = 100 × {(Length after stretching) − (Length before stretching)} / (Length before stretching) Hereinafter, various materials used in the present invention will be described.

(Norbornene resin)
Examples of the norbornene-based resin of the present invention include hydrogenated ring-opening polymers of norbornene-based monomers, addition polymers of norbornene-based monomers and olefins, addition polymers of norbornene-based monomers, and derivatives thereof. . Moreover, only 1 type may be used for norbornene-type resin, and 2 or more types may be used together.

  Examples of the norbornene-based monomer include bicyclo [2,2,1] hept-2-ene (norbornene), 6-methylbicyclo [2,2,1] hept-2-ene, and 5,6-dimethylbicyclo. [2,2,1] hept-2-ene, 1-methylbicyclo [2,2,1] hept-2-ene, 6-ethylbicyclo [2,2,1] hept-2-ene, 6-n -Butylbicyclo [2,2,1] hept-2-ene, 6-isobutylbicyclo [2,2,1] hept-2-ene, 7-methylbicyclo [2,2,1] hept-2-ene, etc. And norbornene derivatives thereof.

  As the ring-opening polymer hydrogenated product of the norbornene-based monomer, those obtained by subjecting the norbornene-based monomer to ring-opening polymerization by a known method and then hydrogenating the remaining double bond can be widely used. The ring-opening polymer hydrogenated product may be a norbornene monomer homopolymer or a copolymer of a norbornene monomer and another cyclic olefin monomer.

  Examples of the addition polymer of norbornene monomer and olefin include a copolymer of norbornene monomer and α-olefin. The α-olefin is not particularly limited, but is an α-olefin having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3 -Methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and the like. Especially, since it is excellent in copolymerizability, ethylene is used suitably. Also, when other α-olefin is copolymerized with a norbornene-based monomer, it is preferable that ethylene is present because the copolymerizability can be improved.

  Examples of the norbornene-based resin include known ones, and are commercially available. Examples of known norbornene-based resins include those described in JP-A-1-240517. Examples of norbornene-based resins that can be obtained commercially include, for example, JSR Co., Ltd., trade name “Arton” series, Nippon Zeon Co., Ltd., trade name “Zeonor” series, and the like.

Furthermore, a saturated norbornene resin having the following structure can be used for the film of the present invention. In the present invention, as saturated norbornene resin,
[A-1]: hydrogenated random copolymer of an α-olefin having 2 to 20 carbon atoms and a cyclic olefin represented by the following formula (I),
[A-2]: A ring-opened polymer or copolymer hydrogenated product of a cyclic olefin represented by the following formula (I) can be exemplified.
Formula (I)

  These saturated norbornene resins have a glass transition temperature (Tg) measured by DSC of preferably 70 ° C. or higher, more preferably 70 to 250 ° C., and further preferably 120 to 180 ° C.

  Further, these saturated norbornene resins are amorphous or low crystalline, and the crystallinity measured by X-ray diffraction method is usually 20% or less, preferably 10% or less, more preferably 2%. It is as follows.

  The saturated norbornene resin of the present invention has an intrinsic viscosity [η] measured in decalin at 135 ° C. of usually 0.01 to 20 dl / g, preferably 0.03 to 10 dl / g, and more Preferably it is 0.05-5 dl / g, The melt flow index (MFR) measured by 260 degreeC load 2.16kg according to ASTM D1238 is 0.1-200 g / 10min normally, Preferably it is 1-100 g / 10 minutes, more preferably 5 to 50 g / 10 minutes.

  Furthermore, the softening point of the cyclic olefin-based resin is usually 30 ° C. or higher, preferably 70 ° C. or higher, more preferably 80 to 260 ° C. as the softening point (TMA) measured with a thermal mechanical analyzer.

  Details of the structure of the saturated norbornene represented by the above formula (I) will be described. In the above formula (I), n is 0 or 1, m is 0 or an integer of 1 or more, and q is 0 or 1. When q is 1, Ra and Rb are each independently the following atoms or hydrocarbon groups. When q is 0, each bond is bonded to form a 5-membered ring. Form.

  R1 to R18 and Ra and Rb are each independently a hydrogen atom, a halogen atom or a hydrocarbon group. Here, the halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. Moreover, as a hydrocarbon group, a C1-C20 alkyl group, a C3-C15 cycloalkyl group, and an aromatic hydrocarbon group are mentioned. More specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an amyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, and an octadecyl group, and the cycloalkyl group includes a cyclohexyl group. Group, and examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group. These hydrocarbon groups may be substituted with a halogen atom. Furthermore, in the above formula (I), R15 to R18 may be bonded to each other (in cooperation with each other) to form a monocyclic or polycyclic ring, and the monocyclic or polycyclic ring thus formed is You may have a double bond.

  Specific examples of the cyclic olefin represented by the above formula (I) are shown below. As an example,

And bicyclo [2.2.1] -2-heptene (= norbornene) represented by the formula (wherein the numbers 1 to 7 represent carbon position numbers) and derivatives in which a hydrocarbon group is substituted on the compound. It is done.

  As this substituted hydrocarbon group, 5-methyl group, 5,6-dimethyl group, 1-methyl group, 5-ethyl group, 5-n-butyl group, 5-isobutyl group, 7-methyl group, 5-phenyl group , 5-methyl-5-phenyl group, 5-benzyl group, 5-tolyl group, 5-ethylphenyl group, 5-isopropylphenyl group, 5-biphenyl group, 5-β-naphthyl group, 5-α-naphthyl group , 5-anthracenyl group, 5,6-diphenyl group and the like.

  Still other derivatives include cyclopentadiene-acenaphthylene adduct, 1,4-methano-1,4,4a, 9a-tetrahydrofluorene, 1,4-methano-1,4,4a, 5,10,10a-hexahydro. Bicyclo [2.2.1] -2-heptene derivatives such as anthracene can be exemplified.

In addition, tricyclo [4.3.0.1 ^2,5 ] -3-decene, 2-methyltricyclo [4.3.0.1 ^2,5 ] -3-decene, 5-methyltricyclo [4 .3.0.1 ^2,5 ] -3-decene and other tricyclo [4.3.0.1 ^2,5 ] -3-decene derivatives, tricyclo [4.4.0.1 ^2,5 ] -3 A tricyclo [4.4.0.1 ^2,5 ] -3-undecene derivative such as undecene, 10-methyltricyclo [4.4.0.1 ^2,5 ] -3-undecene,

Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, and derivatives substituted with a hydrocarbon group. Here, examples of the hydrocarbon group substituted by the derivative include 8-methyl group, 8-ethyl group, 8-propyl group, 8-butyl group, 8-isobutyl group, 8-hexyl group, 8-cyclohexyl group, 8 -Stearyl group, 5,10-dimethyl group, 2,10-dimethyl group, 8,9-dimethyl group, 8-ethyl-9-methyl group, 11,12-dimethyl group, 2,7,9-trimethyl group, 2,7-dimethyl-9-ethyl group, 9-isobutyl-2,7-dimethyl group, 9,11,12-trimethyl group, 9-ethyl-11,12-dimethyl group, 9-isobutyl-11,12- Dimethyl group, 5,8,9,10-tetramethyl group, 8-ethylidene group, 8-ethylidene-9-methyl group, 8-ethylidene-9-ethyl group, 8-ethylidene-9-isopropyl group, 8-ethylidene -9-butyl 8-n-propylidene group, 8-n-propylidene-9-methyl group, 8-n-propylidene-9-ethyl group, 8-n-propylidene-9-isopropyl group, 8-n-propylidene-9-butyl Group, 8-isopropylidene group, 8-isopropylidene-9-methyl group, 8-isopropylidene-9-ethyl group, 8-isopropylidene-9-isopropyl group, 8-isopropylidene-9-butyl group, 8- Chloro group, 8-bromo group, 8-fluoro group, 8,9-dichloro group, 8-phenyl group, 8-methyl-8-phenyl group, 8-benzyl group, 8-tolyl group, 8-ethylphenyl group, Examples include 8-isopropylphenyl group, 8,9-diphenyl group, 8-biphenyl group, 8-β-naphthyl group, 8-α-naphthyl group, 8-anthracenyl group, 5,6-diphenyl group, etc. It can be.

Further, tetracyclo [4.4.0.1 ^2,5 ... Cyclopentadiene-acenaphthylene adduct and cyclopentadiene adduct. 1 ^7,10 ] -3-dodecene derivative, pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13] -4-pentadecene and its derivatives, pentacyclo [7.4.0.1 ^2,5. 1 ^9,12 . 0 ^8,13] -3-pentadecene and its derivatives, pentacyclo [8.4.0.1 ^2,5. 1 ^9,12 . 0 ^8,13] -3-hexadecene and derivatives thereof, pentacyclo [6.6.1.1 ^{3, 6.} 0 ^2,7 . 0 ^9,14] -4-hexadecene and derivatives thereof, hexacyclo [6.6.1.1 ^{3, 6.} 1 ^10,13 . 0 ^2,7 . 0 ^9,14] -4-heptadecene and its derivatives, heptacyclo [8.7.0.1 ^2,9. 1 ^4,7 . 1 ^11,17 . 0 ^3,8 . 0 ^12,16 ] -5-eicosene and its derivatives, heptacyclo [8.7.0.1 ^3,6 . 1 ^10,17 . 1 ^12,15 . 0 ^2,7 . 0 ^11,16 ] -4-eicosene and its derivatives, heptacyclo [8.8.0.1 ^2,9 . 1 ^4,7 . 1 ^11,18 . 0 ^3,8 . 0 ^12,17 ] -5- ^heneicosene and its derivatives, octacyclo [8.8.0.1 ^2,9 . 1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5-docosene and derivatives thereof, nonacyclo [10.9.1.1 ^4,7 . 11 ^3,2 0.1 ^15,18 . 0 ^2,10 . 0 ^3,8 . 0 ^12,21 . 0 ^14,19] -5-pentacosene and derivatives thereof.

  Specific examples of these saturated norbornene resins are as described above, but more specific structures of these compounds are shown in paragraphs 0032 to 0054 of JP-A-7-145213.

  Moreover, about the synthesis method of these saturated norbornene resins, it can carry out with reference to paragraph numbers 0039-0068 of Unexamined-Japanese-Patent No. 2001-114836.

  The saturated norbornene resin of the present invention is derived from at least one polymer unit represented by the following formulas (I) to (VI), or from at least one of these compounds and the compound represented by the following formula (VII). And cycloolefin (co) polymers composed of the following polymerization units. Here, the ratio of the polymerization unit derived from the compound represented by the formula (VII) in the cycloolefin (co) polymer is 0 to 99 mol%.

  In the above formula, R1, R2, R3, R4, R5, R6, R7 and R8 are each a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 18 carbon atoms, carbon It forms a C1-C20 hydrocarbon group such as a C7-20 alkylenearyl group, a C2-C20 alkenyl group which may be cyclic, or a saturated, unsaturated or aromatic cyclic group. n is an integer of 0-5.

In the formula, each of R9, R10, R11 and R12 is a hydrogen atom, or a linear or branched, saturated or unsaturated, such as an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 18 carbon atoms, It is a C1-C20 hydrocarbon group.

  The cycloolefin (co) polymer can be obtained, for example, by ring-opening polymerization of at least one of the monomers having the formulas (I) to (VI) and then hydrogenating the resulting product. it can.

  Moreover, the cycloolefin (co) polymer which contains the polymer unit derived from the compound represented by a following formula (VIII) in the said polymer 0-45 mol% of the whole is also preferable.

In the formula, n is a number of 2 to 10.

  The proportion of polymerized units derived from cyclic, especially polycyclic olefins, is preferably 3 to 75 mol% of the cycloolefin (co) polymer. The proportion of the polymer units derived from the acyclic olefin is preferably 5 to 80 mol% of the cycloolefin (co) polymer.

  The cycloolefin (co) polymer is preferably a polymer unit derived from one or more polycyclic olefins, in particular a polycyclic olefin represented by formula (I) or formula (III), and the formula ( VII) consisting of polymerized units derived from one or more acyclic olefins represented by VII), in particular α-olefins having 2 to 20 carbon atoms. Preferably, it consists in particular of polymerized units derived from polycyclic olefins of formula (I) or formula (III) and polymerized units derived from acyclic olefins of formula (VII) It is a cycloolefin copolymer. Preferably, a polymer unit derived from a polycyclic monoolefin represented by formula I or formula III, a polymer unit derived from an acyclic monoolefin represented by formula (VII), and at least two Cyclic or acyclic olefins (polyenes) containing double bonds, for example, especially cyclic, preferably polycyclic dienes such as norbornadiene, particularly preferably containing, for example, alkenyl groups having 2 to 20 carbon atoms It is a three-dimensional polymer consisting of polymerized units derived from polycyclic alkenes such as vinyl norbornene.

  The cycloolefin (co) polymer used in the present invention preferably contains an olefin based on a norbornene structure, particularly preferably norbornene, tetracyclododecene, and optionally vinyl norbornene or norbornadiene. Also preferred are cycloolefins (copolymers) comprising polymerized units derived from α-olefins having for example 2 to 20 carbon atoms, particularly preferably acyclic olefins having terminal double bonds such as ethylene or propylene. ) Polymer. Particularly preferred are norbornene / ethylene copolymers and tetracyclododecene / ethylene copolymers.

  Among the three-dimensional polymers, three-dimensional polymers of norbornene / vinylnorbornene / ethylene, norbornene / norbornadiene / ethylene terpolymer, tetracyclododecene / vinylnorbornene / ethylene terpolymer, and tetracyclododecene / vinyl are particularly preferable. Tetracyclododecene-ethylene three-dimensional polymer. The proportion of polymerized units derived from polyenes, preferably vinyl norbornene or norbornadiene, is 0.1 to 50 mol%, particularly preferably 0.1 to 20 mol%, based on the total structure of the cycloolefin (co) polymer. The ratio of the acyclic monoolefin represented by the formula (VII) is usually 0 to 99 mol%, preferably 5 to 80 mol%. In the said three-dimensional polymer, Preferably it is 0.1-99 mol% of a cycloolefin (co) polymer, More preferably, it is 3-75 mol%.

  The cycloolefin (co) polymer used in the present invention is preferably a polymer unit that can be derived from a polycyclic olefin represented by the formula (I) and an acyclic olefin represented by the formula (VII). It contains at least one cycloolefin (co) polymer containing polymerized units that can be derived.

  Such cycloolefin (co) polymer can be synthesized according to paragraph numbers 0019 to 0020 of JP-A-10-168201.

  In the present invention, as described above, various additives may be added to the thermoplastic resin as necessary as long as the achievement of the object of the present invention is not hindered. Examples of such additives include various additives that prevent deterioration of the thermoplastic resin and improve the heat resistance, ultraviolet resistance, smoothness, etc. of the molded optical film. Antioxidants, lactone-based thermal deterioration inhibitors, benzophenone-based, benzotriazole-based, acrylonitrile-based ultraviolet absorbers; aliphatic alcohol ester-based, polyhydric alcohol partial ester-based and partial ether-based lubricants; Examples include amine-based antistatic agents and plasticizers. One or more of these additives may be added as described above.

  In the above-described norbornene-based resin, the flow value can be easily adjusted by adding an internal lubricant such as an aliphatic alcohol ester, a polyhydric alcohol partial ester, or a partial ether.

(Additive)
(1) Antioxidant The norbornene resin in the present invention includes known antioxidants such as 2,6-di-t-butyl-4-methylphenol, 2,2′-dioxy-3,3′-di. -T-butyl-5,5'-dimethylphenylmethane, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris (2- Methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, stearyl- β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-dioxy-3,3′-di-tert-butyl-5,5′-diethylphenylmethane, 3,9 -Bis [1,1-dimethyl Ru-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl], 2,4,8,10-tetraoxospiro [5,5] undecane, tris (2 , 4-Di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-t) -Butyl-4-methylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite; UV absorbers such as 2,4-dihydroxybenzophenone, 2-hydroxy-4- It can be stabilized by adding methoxybenzophenone or the like. Further, additives such as a lubricant can be added for the purpose of improving processability.

  The addition amount of these antioxidants is 0.1-3 mass parts normally with respect to 100 mass parts of norbornene-type resin, Preferably it is 0.2-2 mass parts.

  Further, the norbornene-based resin may be added with various additives such as an anti-aging agent such as a phenol-based resin or a phosphorus-based resin, an antistatic agent, an ultraviolet absorber, and an easy-to-lubricant.

(2) Stabilizer In the present invention, it is preferable to use either or both of a phosphite compound and a phosphite compound as a stabilizer. The blending amount of these stabilizers is preferably 0.005 to 0.5% by mass with respect to the cycloolefin resin, more preferably 0.01 to 0.4% by mass, and still more preferably 0.8. It is 02-0.3 mass%.

a. Phosphite stabilizers Specific phosphite stabilizers are not particularly limited, but phosphite stabilizers represented by formulas (2) to (4) are preferable.

In the above formulas, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ′ ¹ , R ′ ² , R ′ ³ ... R ′ ^p and R ′ ^{p + 1} are hydrogen or carbon. A group consisting of an alkyl group, an aryl group, an alkoxyalkyl group, an aryloxyalkyl group, an alkoxyaryl group, an arylalkyl group, an alkylaryl group, a polyaryloxyalkyl group, a polyalkoxyalkyl group, and a polyalkoxyaryl group of formula 4-23 Represents a group selected from However, not all of the same formulas in the general formulas (2), (3), and (4) become hydrogen. X in the phosphite stabilizer represented by the general formula (3) is an aliphatic chain, an aliphatic chain having an aromatic nucleus in a side chain, an aliphatic chain having an aromatic nucleus in the chain, and two in the chain. A group selected from the group consisting of chains containing non-continuous oxygen atoms. K and q are integers of 1 or more, and p is an integer of 3 or more.

  The values of k and q of these phosphite stabilizers are preferably 1 to 10. Setting the values of k and q to 1 or more reduces the volatility during heating, and setting it to 10 or less is preferable because compatibility with cellulose acetate propionate is improved. Moreover, the value of p is preferably 3 to 10. By setting p to a value of 3 or more, volatility during heating is reduced, and setting it to 10 or less is preferable because compatibility with cellulose acetate propionate is improved.

b. Phosphite stabilizers The phosphite stabilizers include, for example, cyclic neopentanetetraylbis (octadecyl) phosphite, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) Phosphite, cyclic neopentanetetraylbis (2,6-di-tert-butyl-4-methylphenyl) phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, And tris (2,4-di-tert-butylphenyl) phosphite.

c. Other stabilizers In addition, weak organic acids, thioether compounds, epoxy compounds and the like may be added as stabilizers. The weak organic acid is not particularly limited as long as it has a pKa of 1 or more, does not interfere with the action of the present invention, and has coloration prevention properties and physical property deterioration prevention properties. Examples thereof include tartaric acid, citric acid, malic acid, fumaric acid, oxalic acid, succinic acid, maleic acid and the like. These may be used alone or in combination of two or more.

  Examples of the thioether compound include dilauryl thiodipropionate, ditridecyl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, and palmityl stearyl thiodipropionate. It may be used in combination, or two or more may be used in combination.

  Examples of the epoxy compound include those derived from epichlorohydrin and bisphenol A, such as derivatives from epichlorohydrin and glycerin, vinylcyclohexene dioxide, and 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6. -Cyclic ones such as methylcyclohexanecarboxylate can also be used. Epoxidized soybean oil, epoxidized castor oil, long chain α-olefin oxides, and the like can also be used. These may be used alone or in combination of two or more.

(3) Matting agent It is preferable to add fine particles as a matting agent. The fine particles used in the present invention include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and Mention may be made of calcium phosphate.

  These fine particles usually form secondary particles having an average particle size of 0.1 to 3.0 μm, and these fine particles exist in the film as aggregates of primary particles, and 0.1 to 0.1 μm on the film surface. An unevenness of 3.0 μm is formed. The secondary average particle size is preferably 0.2 μm to 1.5 μm, more preferably 0.4 μm to 1.2 μm, and most preferably 0.6 μm to 1.1 μm. For the primary and secondary particle sizes, the particles in the film were observed with a scanning electron microscope, and the diameter of a circle circumscribing the particles was defined as the particle size. In addition, 200 particles were observed at different locations, and the average value was taken as the average particle size.

  A preferable addition amount of the fine particles is preferably 1 ppm to 5000 ppm, more preferably 5 ppm to 1000 ppm, and still more preferably 10 ppm to 500 ppm by mass ratio with respect to the norbornene resin.

  Fine particles containing silicon are preferable because turbidity can be lowered, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary average particle size of 20 nm or less and an apparent specific gravity of 70 g / liter or more. Those having an average primary particle size as small as 5 to 16 nm are more preferred because they can reduce the haze of the film. The apparent specific gravity is preferably 90 to 200 g / liter or more, and more preferably 100 to 200 g / liter or more. A larger apparent specific gravity is preferable because a high-concentration dispersion can be produced, and haze and aggregates are improved.

  As the fine particles of silicon dioxide, for example, commercially available products such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above, manufactured by Nippon Aerosil Co., Ltd.) can be used. 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.

  Among these, Aerosil 200V and Aerosil R972V are fine particles of silicon dioxide having a primary average particle size of 20 nm or less and an apparent specific gravity of 70 g / liter or more, so that friction is maintained while keeping the turbidity of the optical film low. This is particularly preferable because the effect of reducing the coefficient is great.

(4) Other additives As other additives, infrared absorbing dyes, optical adjusting agents, and surfactants can be added. These details are disclosed in the Invention Association Public Technique No. 2001-1745 (issued March 15, 2001, Invention Association), p. Materials described in detail in 17-22 are preferably used.

  As the infrared absorbing dye, for example, those disclosed in JP-A No. 2001-194522 can be used, and as the ultraviolet absorber, for example, those described in JP-A No. 2001-151901 can be used. It is preferable to contain 001-5 mass%.

  Examples of the optical adjusting agent include a retardation adjusting agent. For example, those described in JP 2001-166144 A, JP 2003-344655 A, JP 2003-248117 A, and JP 2003-66230 A. Can be used. Thereby, in-plane retardation (Re) and thickness direction retardation (Rth) can be controlled. A preferable addition amount is 0 to 10% by mass with respect to cellulose acylate, more preferably 0 to 8% by mass, and still more preferably 0 to 6% by mass.

  As the ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, an acrylonitrile-based ultraviolet absorber, or the like can be used. Among them, a benzophenone-based ultraviolet absorber is preferable, and the addition amount is usually 10 to 10. 100,000 ppm, preferably 100 to 10,000 ppm.

(Film formation)
(1) Pelletization The thermoplastic resin and the additive are preferably mixed and pelletized prior to melt film formation.

  It is preferable to dry the thermoplastic resin and the additive in advance for pelletization, but drying can be substituted by using a vent type extruder. When drying, as the drying method, a method of heating in a heating furnace at 90 ° C. for 8 hours or more can be used, but not limited thereto. Pelletization can be performed by melting the thermoplastic resin and additives at 150 ° C. to 280 ° C. using a twin-screw kneading extruder and then extruding them into noodles and solidifying and cutting in water. Further, pelletization may be performed by an underwater cutting method or the like that is cut while being directly extruded from a die after being melted by an extruder.

  Any known single-screw extruder, non-meshing counter-rotating twin-screw extruder, meshing-type counter-rotating twin-screw extruder, meshing-type co-direction as long as the extruder is sufficiently melt kneaded A rotary twin screw extruder or the like can be used.

The preferred size is the cross-sectional area of ^{1 mm} 2 to 300 mm ² of the pellets, is 1mm~30mm is Preferably length, more preferably the cross-sectional area of ^{2 mm} 2 100 mm ^2, the length is 1.5Mm～10mm.

  Moreover, when pelletizing, the said additive can also be injected | thrown-in from the raw material input port and vent port in the middle of an extruder.

  The number of revolutions of the extruder is preferably 10 rpm to 1000 rpm, more preferably 20 rpm to 700 rpm, and even more preferably 30 rpm to 500 rpm. Accordingly, when the rotational speed is slow, the residence time becomes long, which is not preferable because the molecular weight is lowered due to thermal deterioration or the yellowishness is easily deteriorated. On the other hand, if the rotational speed is too high, molecules are likely to be cut by shearing, which leads to problems such as a decrease in molecular weight and an increase in the generation of cross-linked gel.

  The extrusion residence time in pelletization is 10 seconds or more and within 30 minutes, more preferably 15 seconds to 10 minutes, and further preferably 30 seconds to 3 minutes. If sufficient melting is possible, a shorter residence time is preferable in terms of suppressing resin deterioration and yellowing.

(2) Drying It is preferable to reduce moisture in the pellets prior to melt film formation. The drying method is often dried using a dehumidifying air dryer, but is not particularly limited as long as the desired moisture content can be obtained (heating, blowing, decompressing, stirring, etc. alone or in combination) It is preferable to use it efficiently, and it is more preferable to use a dry hopper heat insulating structure. The drying temperature is preferably 0 to 200 ° C, more preferably 40 to 180 ° C, and particularly preferably 60 to 150 ° C. When the drying temperature is too low, not only does drying take time, but the moisture content does not fall below the target value, which is not preferable. On the other hand, if the drying temperature is too high, the resin sticks and is not preferable. The amount of drying air used is preferably 20 to 400 m ³ / time, more preferably 50 to 300 m ³ / hour, and particularly preferably 100 to 250 m ³ / hour. If the amount of drying air is small, the drying efficiency is unfavorable. On the other hand, even if the air volume is increased, if the amount is more than a certain amount, further improvement of the drying effect is small and not economical. The dew point of air is preferably 0 to -60 ° C, more preferably -10 to -50 ° C, and particularly preferably -20 to -40 ° C. The drying time is required to be at least 15 minutes, more preferably 1 hour or more, and particularly preferably 2 hours or more. On the other hand, even if it is dried for more than 50 hours, the effect of further reducing the moisture content is small, and there is a concern about thermal degradation of the resin. The thermoplastic resin of the present invention preferably has a moisture content of 1.0% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.01% by mass or less.

(3) Melt extrusion The norbornene-based resin described above is supplied into the cylinder via the supply port of the extruder. By setting the temperature of the resin charged in the extruder to Tg-20 to Tg-90 ° C., the resin is deaerated when transported by the screw in the extruder, and the generation of foreign matters is reduced.

  The cylinder was melt kneaded and compressed in order from the supply port side, a supply part (region A) for quantitatively transporting the thermoplastic resin supplied from the supply port, and a compression unit (region B) for melt kneading and compressing the thermoplastic resin. It is comprised with the measurement part (area | region C) which measures a thermoplastic resin. The resin is preferably dried in order to reduce the water content by the above-mentioned method. However, in order to prevent oxidation of the molten resin by residual oxygen, the inside of the extruder is in an inert (nitrogen or the like) air flow or with a vent. More preferably, it is carried out while evacuating using an extruder. The screw compression ratio of the extruder is set to 2.5 to 4.5, and L / D is set to 20 to 70. Here, the screw compression ratio is represented by the volume ratio between the supply unit A and the metering unit C, that is, the volume per unit length of the supply unit A ÷ the volume per unit length of the metering unit C. It is calculated using the outer diameter d1 of the shaft, the outer diameter d2 of the screw shaft of the measuring part C, the groove part diameter a1 of the supply part A, and the groove part diameter a2 of the measuring part C. L / D is the ratio of the cylinder length to the cylinder inner diameter. Moreover, extrusion temperature is set to 200-300 degreeC. The temperatures in the extruder may all be the same temperature or may have a temperature distribution. More preferably, the temperature of the supply section is made higher than the temperature of the compression section.

  If the screw compression ratio is less than 2.5 and is too small, it will not be sufficiently melt-kneaded and undissolved parts will occur, undissolved foreign matter will easily remain in the manufactured thermoplastic film, and bubbles will be mixed. It becomes easy. As a result, the strength of the thermoplastic film is lowered, or when the film is stretched, it becomes easy to break and the orientation cannot be sufficiently increased. On the other hand, if the screw compression ratio exceeds 4.5, the shear stress is excessively applied and the resin is easily deteriorated by heat generation, so that a yellowish color is likely to appear in the manufactured thermoplastic film. On the other hand, when too much shear stress is applied, the molecules are cut and the molecular weight is lowered, so that the mechanical strength of the film is lowered. Therefore, the screw compression ratio is preferably in the range of 2.5 to 4.5, more preferably 2. In order to make the thermoplastic film after production hardly yellow, and the film strength is strong and the film is not easily stretched and broken. It is 8 to 4.2, particularly preferably in the range of 3.0 to 4.0.

  On the other hand, if L / D is less than 20 and is too small, melting and kneading are insufficient, and undissolved foreign matter is likely to be generated in the manufactured thermoplastic film as in the case where the compression ratio is small. On the other hand, if L / D exceeds 70 and is too large, the residence time of the thermoplastic resin in the extruder becomes too long, and the resin tends to be deteriorated. Further, when the residence time is long, the molecules are cut or the molecular weight is lowered, so that the mechanical strength of the thermoplastic film is lowered. Therefore, L / D is preferably in the range of 20 to 70, more preferably in the range of 22 to 65, in order to make the thermoplastic film after production hardly yellowish and the film strength is strong and further difficult to stretch and break. Especially preferably, it is the range of 24-50.

  Generally, single-screw extruders with relatively low equipment costs are often used as the types of extruders, and there are screw types such as full flight, madok, and dalmage. Is preferred. In addition, although the equipment cost is expensive, it is possible to use a twin-screw extruder that can extrude while volatilizing unnecessary volatile components by providing a vent port in the middle by changing the screw segment. There are two types of shaft extruders, the same direction and the different direction, which can be used. However, the type of the same direction rotation with high self-cleaning performance is preferred because a stagnant portion is hardly generated. By properly arranging the vent port, it is possible to use the cycloolefin pellets and powder in an undried state as they are. In addition, film smears produced during film formation can be reused without drying.

  In addition, although the diameter of a preferable screw changes with target extrusion rates per unit time, it is 10 mm-300 mm, More preferably, it is 20 mm-250 mm, More preferably, it is 30 mm-150 mm.

(4) Filtration It is preferable to perform a so-called breaker plate type filtration in which a filter medium is provided at the exit of the extruder for filtering foreign matter in the resin and avoiding damage to the gear pump due to foreign matter. At this time, it can be achieved by adjusting the pore diameter of the filter medium and the flow rate of the molten resin as described above.

  In order to filter foreign matter with higher accuracy, it is preferable to provide a filtration device incorporating a so-called leaf type disk filter after passing through the gear pump. Filtration can be performed by providing one filtration section, or multistage filtration performed by providing a plurality of places. Although the filtration accuracy of the filter medium is preferably higher, the filtration accuracy is preferably 15 μm to 3 μmm, more preferably 10 μm to 3 μm, from the viewpoint of the pressure resistance of the filter medium and the increase in the filtration pressure due to clogging of the filter medium. In particular, when using a leaf-type disk filter device that finally filters foreign matter, it is preferable to use a filter medium with high filtration accuracy in terms of quality, and it is adjusted by the number of loaded sheets to ensure the suitability of pressure resistance and filter life. Is possible. The type of filter medium is preferably a steel material because it is used under high temperature and high pressure. Among steel materials, stainless steel, steel, etc. are particularly preferable, and stainless steel is particularly preferable in terms of corrosion. . As a configuration of the filter medium, for example, a sintered filter medium formed by sintering metal long fibers or metal powder can be used in addition to a knitted wire, and a sintered filter medium is preferable in terms of filtration accuracy and filter life.

(5) Gear pump In order to improve the thickness accuracy, it is important to reduce the fluctuation of the discharge amount. A gear pump is provided between the extruder and the die, and a certain amount of cellulose acylate resin is supplied from the gear pump. Is effective. A gear pump is housed in a state where a pair of gears consisting of a drive gear and a driven gear are engaged with each other, and the drive gear is driven to engage and rotate the two gears, so that a melted state is generated from the suction port formed in the housing. Resin is sucked into the cavity, and a certain amount of the resin is discharged from a discharge port formed in the housing. Even if there is a slight fluctuation in the resin pressure at the front end of the extruder, the fluctuation is absorbed by using a gear pump, the fluctuation in the resin pressure downstream of the film forming apparatus becomes very small, and the thickness fluctuation is improved. By using a gear pump, it is possible to keep the fluctuation range of the resin pressure in the die portion within ± 1%.

  In order to improve the quantitative supply performance by the gear pump, a method of controlling the pressure before the gear pump to be constant by changing the number of rotations of the screw can also be used. In addition, a high-precision gear pump using three or more gears that eliminates gear fluctuations of the gear pump is also effective.

  Other advantages of using a gear pump are that the pressure at the screw tip can be reduced to form a film, reducing energy consumption, preventing rise in resin temperature, improving transport efficiency, shortening the residence time in the extruder, L / D can be expected to be shortened. In addition, when using a filter to remove foreign matter, if there is no gear pump, the amount of resin supplied from the screw may fluctuate as the filtration pressure increases. It can be resolved. On the other hand, the disadvantages of gear pumps are that the length of the equipment will be longer depending on the equipment selection method, the resin residence time will be longer, and the shearing stress of the gear pump may cause the molecular chain to break. is required.

  The preferred residence time of the resin from the supply port through the extruder until it exits the die is 2 minutes to 60 minutes, more preferably 3 minutes to 40 minutes, and even more preferably 4 minutes to 30 minutes. is there.

  The deterioration of the flow of the polymer for bearing circulation of the gear pump deteriorates the sealing by the polymer in the drive part and the bearing part, and the problem of increase in the metering and liquid feed extrusion pressure occurs. A gear pump design (especially clearance) that matches the melt viscosity is required. In some cases, the staying portion of the gear pump causes deterioration of the thermoplastic resin, so that a structure with as little staying as possible is preferable. The polymer pipes and adapters that connect the extruder and gear pump or gear pump and die also need to have a design with as little stagnation as possible, and to stabilize the extrusion pressure of thermoplastic resins with high temperature dependence of melt viscosity. It is preferable to make the temperature fluctuation as small as possible. Generally, a band heater having a low equipment cost is often used for heating the polymer tube, but it is more preferable to use an aluminum cast heater with less temperature fluctuation. Further, in the extruder as described above, it is preferable that the barrel of the extruder is heated and melted with a heater divided into 3 to 20.

(6) Die The thermoplastic resin is melted by the extruder configured as described above, and the molten resin is continuously sent to the die via a filter and a gear pump as necessary. As long as the die is designed so that the molten resin stays in the die, any type of commonly used T die, fishtail die, and hanger coat die may be used. Also, there is no problem in placing a static mixer for improving the uniformity of the resin temperature immediately before the T die. The clearance at the T-die exit portion is generally 1.0 to 5.0 times the film thickness, preferably 1.2 to 3 times, and more preferably 1.3 to 2 times. When the lip clearance is 1.0 times smaller than the film thickness, it is difficult to obtain a good sheet by film formation. Further, when the lip clearance is larger than 5.0 times the film thickness, the sheet thickness accuracy is lowered, which is not preferable. The die is a very important facility for determining the thickness accuracy of the film, and a die capable of strictly controlling the thickness adjustment is preferable. Normally, the thickness can be adjusted at intervals of 40 to 50 mm, but preferably a type capable of adjusting the film thickness at intervals of 35 mm or less, more preferably at intervals of 25 mm or less. In addition, in order to improve the uniformity of the film-forming film, it is important to design the die as little as possible in the temperature unevenness of the die and in the width direction. An automatic thickness adjustment die that measures the downstream film thickness, calculates the thickness deviation, and feeds back the result to the die thickness adjustment is also effective in reducing the thickness fluctuation in long-term continuous production.

  For production of a film, a single-layer film forming apparatus with a low equipment cost is generally used. However, in some cases, a film having two or more types of structures can also be manufactured using a multilayer film forming apparatus in order to provide a functional layer on an outer layer. Is possible. In general, the functional layer is preferably thinly laminated on the surface layer, but the layer ratio is not particularly limited.

(7) Casting Under the above conditions, the molten resin extruded from the die onto the sheet is cooled and solidified on the casting drum to obtain a film.

  In the present invention, it is preferable to use a method such as electrostatic application method, air knife method, air chamber method, vacuum nozzle method, touch roll method, etc. on the casting drum to improve the adhesion between the casting drum and the melt-extruded sheet. It is preferable to use the touch roll method described above.

  In the touch roll method, a touch roll is placed on a cast drum to shape the film surface. At this time, the touch roll is preferably not elastic and usually elastic. However, if the elastically deformable member (rubber etc.) is covered with an extremely thin metal, the surface pressure cannot be increased (the deformation amount of the Tachiroll is large, the contact area with the cast roll becomes too large, and the sufficient surface pressure is reduced. It is not preferable because it cannot be used.

  The touch roll usually uses a rigid material, but if it is too rigid, residual strain is likely to occur when the melt from the die is sandwiched between the rolls, further promoting partial strain. For this reason, it is preferable that the material of the touch roll has elasticity. As a result, the excessive surface pressure is absorbed by the deformation of the touch roll and the distortion is suppressed. In order to give elasticity to the roll, it is necessary to make the outer cylinder thickness of the roll thinner than a normal roll, and the outer wall thickness Z is preferably 0.05 mm to 7.0 mm, more preferably 0.2 mm to 5.0 mm. More preferably, it is 0.3 mm-3.5 mm. The touch roll may be installed on a metal shaft and a heat medium (fluid) may be passed between them. An elastic layer is provided between the outer cylinder and the metal shaft, and the heat medium (fluid) is filled between the outer cylinders. Can be mentioned.

  Since the touch roll has low elasticity in this way, when it is brought into contact with the casting roll, it is elastically deformed into a concave shape by the pressing. Therefore, since the touch roll and the casting roll are in surface contact with the cooling roller, the pressure is dispersed and a low surface pressure can be achieved. For this reason, uniform cooling can be achieved without leaving a residual distortion in the film sandwiched therebetween. The linear pressure of the preferred touch roll is 1 kg / cm to 100 kg / cm, more preferably 2 kg / cm to 80 kg / cm, and still more preferably 3 kg / cm to 60 kg / cm. The linear pressure referred to here is a value obtained by dividing the force applied to the touch roll by the width of the discharge port of the die. If the linear pressure is less than the above range, the pressing force of the touch roll is weak and the non-uniformity in the surface cannot be corrected. On the other hand, if the linear pressure exceeds the linear pressure, a uniform linear pressure cannot be applied over the entire width (the roll is bent at both ends or Non-uniformity is likely to increase (linear pressure tends to concentrate in the center).

  The touch roll is preferably set to 60 ° C to 160 ° C, more preferably 70 ° C to 150 ° C, and still more preferably 80 ° C to 140 ° C. Such temperature control can be achieved by passing a temperature-controlled liquid or gas through these rolls.

  The touch roll and casting roll preferably have a mirror surface, and the arithmetic average height Ra is 100 nm or less, preferably 50 nm or less, more preferably 25 nm or less. Specifically, for example, JP-A No. 11-314263, JP-A No. 2002-36332, JP-A No. 11-235747, International Publication No. WO 97/28950, JP-A No. 2004-216717, JP-A No. 2003-145609. Can be used.

By forming a touch roll in this way, the elastic modulus of the thermoplastic film is preferably 2.9 kN / mm ² or less, more preferably 1.2 kN / mm ^{2 to} 2.8 kN / mm ² , and even more preferably 1. It can be set to 5 kN / mm ^{2 to} 2.7 kN / mm ² . Since the molten resin (melt) can be rapidly cooled with the casting roll by using the touch roll, the crystal growth can be suppressed and the elastic modulus can be lowered. Furthermore, since the melt having a large free volume at a high temperature is cooled and solidified as it is, it becomes a low-density film and the elastic modulus is lowered. Thus, by making it low elasticity modulus, the shrinkage stress of the width direction generate | occur | produced by neck-in can be made small, and the retardation change by a residual strain can be made small.

  More preferably, a plurality of casting drums (rollers) are used for slow cooling (of which the touch roll is arranged so as to touch the first casting roll on the most upstream side (closer to the die). ). In general, it is relatively common to use three cooling rollers, but this is not a limitation. The diameter of the roller is preferably 50 mm to 5000 mm, more preferably 100 mm to 2000 mm, and still more preferably 150 mm to 1000 mm. The interval between the plurality of rollers is preferably 0.3 mm to 300 mm, more preferably 1 mm to 100 mm, and still more preferably 3 mm to 30 mm. The casting drum is preferably 60 ° C to 160 ° C, more preferably 70 ° C to 150 ° C, still more preferably 80 ° C to 140 ° C.

(8) Winding After peeling off from the casting drum, it winds up through a nip roll.

  The film forming width is 0.7 m to 5 m, more preferably 1 m to 4 m, and still more preferably 1.3 m to 3 m. The thickness of the unstretched film thus obtained is preferably 20 μm to 250 μm, more preferably 25 μm to 200 μm, still more preferably 30 μm to 180 μm.

  It is also preferable to trim both ends before winding. As the trimming cutter, any type of rotary cutter, shear blade, knife, or the like may be used. As for the material, either carbon steel or stainless steel may be used. In general, it is preferable to use a cemented carbide blade or a ceramic blade because the life of the blade is long and the generation of chips is suppressed. The portion cut off by trimming may be crushed and used again as a raw material.

  It is also preferable to perform a thickness increasing process (knurling process) at one or both ends. The height of the unevenness due to the thickness increasing process is preferably 1 μm to 200 μm, more preferably 10 μm to 150 μm, and still more preferably 20 μm to 100 μm. Thickening processing may be convex on both sides or convex on one side. The width of the thickness increasing process is preferably 1 mm to 50 mm, more preferably 3 mm to 30 mm, and still more preferably 5 mm to 20 mm. Extrusion can be performed at room temperature to 300 ° C.

  The film thus formed may be stretched as it is (online stretching), or after being wound up, it may be sent out again and stretched (offline stretching).

  At the time of winding, it is also preferable to attach a lami film on at least one side from the viewpoint of preventing scratches. The thickness of the laminated film is preferably 5 μm to 200 μm, preferably 10 μm to 150 μm, and preferably 15 μm to 100 μm. The material is not particularly limited, such as polyethylene, polyester, and polypropylene.

  A preferable winding tension is 1 kg / m width to 50 kg / width, more preferably 2 kg / m width to 40 kg / width, and still more preferably 3 kg / m width to 20 kg / width. When the winding tension is smaller than 1 kg / m width, it is difficult to wind the film uniformly. On the other hand, when the winding tension exceeds 50 kg / width, the film becomes tightly wound, not only the appearance of the winding is deteriorated, but also the bump portion of the film extends due to the creep phenomenon, and the film wave This is not preferable because it causes a cause or residual birefringence due to the elongation of the film. The winding tension is preferably detected by tension control in the middle of the line and is wound while being controlled to have a constant winding tension. If there is a difference in film temperature depending on the location of the film production line, the length of the film may be slightly different due to thermal expansion. It is necessary to prevent tension.

  The winding tension can be wound at a constant tension by controlling the tension control. However, it is more preferable that the winding tension is tapered to an appropriate winding tension according to the wound diameter. Generally, the tension is gradually reduced as the winding diameter increases, but in some cases, it may be preferable to increase the tension as the winding diameter increases.

(Stretching process)
The norbornene-based resin that has been melt-formed may be subjected to transverse stretching and longitudinal stretching, and may be subjected to relaxation treatment in combination with these. These can be implemented by, for example, the following combinations.
1 transverse stretching 2 transverse stretching → relaxation treatment 3 longitudinal stretching → lateral stretching 4 longitudinal stretching → lateral stretching → relaxation treatment 5 longitudinal stretching → relaxation treatment → lateral stretching → relaxation treatment 6 transverse stretching → longitudinal stretching → relaxation treatment 7 transverse stretching → relaxation Treatment → longitudinal stretching → relaxation treatment 8 longitudinal stretching → lateral stretching → longitudinal stretching 9 longitudinal stretching → lateral stretching → longitudinal stretching → relaxation treatment
10 Longitudinal stretching
11 Longitudinal stretching → relaxation treatment Among these, 1-4, 10-11 are more preferable, and 2, 4, 11 are more preferable. Among these, 1 to 4 is more preferable, and 2 and 4 are more preferable.

(Longitudinal stretching)
In the present invention, it is also preferable to carry out by combining transverse stretching and longitudinal stretching. In this case, it is more preferable to perform transverse stretching after longitudinal stretching.

  Longitudinal stretching can be achieved by installing two pairs of nip rolls and heating the gap between them so that the peripheral speed of the nip roll on the outlet side is higher than the peripheral speed of the nip roll on the inlet side. Under the present circumstances, the expression of the retardation of the thickness direction can be changed by changing the space | interval (L) between nip rolls, and the film width (W) before extending | stretching. When L / W (referred to as aspect ratio) exceeds 2 and is 50 or less (long span stretching), Rth can be decreased, and when the aspect ratio is 0.01 or more and 0.3 or less (short span stretching), Rth can be increased. In the present invention, any of a long span stretching, a short span stretching, and a region between them (intermediate stretching = L / W is more than 0.3 and 2 or less) may be used. Short span stretching is preferred. Further, when aiming at high Rth, it is more preferable to use short span stretching, and when aiming at low Rth, it is distinguished from long span stretching.

(1-1) The film is stretched along with the long span stretching. At this time, the film is reduced in thickness and width in order to reduce the volume change. At this time, shrinkage in the width direction is limited by friction between the nip roll and the film. For this reason, when the nip roll interval is increased, shrinkage in the width direction is facilitated, and thickness reduction can be suppressed. When the thickness reduction is large, the same effect as that in which the film is compressed in the thickness direction is obtained, and molecular orientation advances in the film plane and Rth tends to increase. On the contrary, when the aspect ratio is large and the thickness reduction is small, Rth hardly appears and low Rth can be realized.

  Furthermore, if the aspect ratio is long, the uniformity in the width direction can be improved. This is due to the following reason.

  Along with the longitudinal stretching, the film tends to shrink in the width direction. At the central portion in the width direction, both sides thereof also try to contract in the width direction, so that it becomes a tug of war and cannot be contracted freely.

  On the other hand, the film width direction end part is in a tug-of-war state only on one side and can be contracted relatively freely.

  The difference in shrinkage behavior associated with the stretching between the both ends and the central portion becomes the stretching unevenness in the width direction.

  Due to such non-uniformity between both ends and the center, retardation in the width direction and axial deviation (orientation angle distribution of slow axis) occur. On the other hand, since long span stretching is performed slowly between two long nip rolls, uniformity of these non-uniformities (uniform molecular orientation) proceeds during stretching. On the other hand, in normal longitudinal stretching (aspect ratio = more than 0.3 and less than 2), such homogenization does not occur.

  The aspect ratio is more than 2 and preferably 50 or less, more preferably 3 to 40, still more preferably 4 to 20. A preferred stretching temperature is (Tg-5 ° C) to (Tg + 100) ° C, more preferably (Tg) to (Tg + 50) ° C, and still more preferably (Tg + 5) to (Tg + 30) ° C. A preferable draw ratio is 1.05 to 3 times, more preferably 1.05 to 1.7 times, and still more preferably 1.05 to 1.4 times. Such long span stretching may be performed in multiple stages with three or more pairs of nip rolls, as long as the longest aspect ratio is within the above range.

  Such long span stretching may be performed by heating the film between two pairs of nip rolls separated by a predetermined distance. The heating method is a heater heating method (infrared heater, halogen heater, panel heater, etc. above or below the film). Or heating by radiant heat) or a zone heating method (heating in a zone in which hot air or the like is blown and adjusted to a predetermined temperature) may be used. In the present invention, the zone heating method is preferable from the viewpoint of uniformity of the stretching temperature. At this time, the nip roll may be installed in the stretching zone or out of the zone, but it is preferably out of the zone in order to prevent the film and the nip roll from sticking. It is also preferable to preheat the film before such stretching, and the preheating temperature is Tg-80 ° C or higher and Tg + 100 ° C or lower.

  By such stretching, the Re value is 0 to 200 nm, more preferably 10 to 200 nm, further preferably 15 nm to 100 nm, the Rth value is 30 to 500 nm, more preferably 50 to 400 nm, and further preferably 70 to 350 nm. . By this stretching method, the ratio of Rth and Re (Rth / Re) can be 0.4 to 0.6, more preferably 0.45 to 0.55. A film having such characteristics can be used as an A plate type retardation plate. Furthermore, by this stretching, both the Re value and the Rth value can be 5% or less, more preferably 4% or less, and even more preferably 3% or less.

  With such stretching, the ratio of the film width before and after stretching (film width after stretching / film width before stretching) is 0.5 to 0.9, more preferably 0.6 to 0.85, more preferably 0.65 to 0.83.

(1-2) Short span stretching Longitudinal stretching with an aspect ratio (L / W) exceeding 0.01 and less than 0.3, more preferably 0.03 to 0.25, and even more preferably 0.05 to 0.2. (Short span stretching) is performed. By performing stretching at an aspect ratio (L / W) in such a range, neck-in (shrinkage in a direction orthogonal to stretching accompanying stretching) can be reduced. The width and thickness are reduced to compensate for stretching in the stretching direction. However, in such short span stretching, width shrinkage is suppressed and thickness reduction proceeds preferentially. As a result, it becomes compressed in the thickness direction, and the orientation (plane orientation) in the thickness direction advances. As a result, Rth, which is a measure of anisotropy in the thickness direction, tends to increase. On the other hand, conventionally, the aspect ratio (L / W) is generally about 1 (0.7 to 1.5). This is usually done by installing a heater for heating between the nip rolls, but if the L / W is too large, the film cannot be heated uniformly with the heater and uneven stretching tends to occur. If the L / W is too small, the heater is stretched. This is because it is difficult to install and cannot be heated sufficiently.

  The short span stretching described above can be performed by changing the transport speed between two or more pairs of nip rolls, but unlike the normal roll arrangement (FIG. 1), the two pairs of nip rolls are slanted (the rotation axes of the front and rear nip rolls are moved up and down). This can be achieved by disposing (Fig. 2). Accordingly, since a heater for heating cannot be installed between the nip rolls, it is preferable to raise the temperature of the film by flowing a heating medium in the nip rolls. Further, it is also preferable to provide a preheating roll in which a heating medium is flowed inside before the entrance side nip roll and heat the film before stretching.

  The preferred stretching temperature is (Tg−5 ° C.) to (Tg + 100) ° C., more preferably (Tg) to (Tg + 50) ° C., still more preferably (Tg + 5) to (Tg + 30) ° C., and the preferred preheating temperature is Tg−. It is 80 degreeC or more and Tg + 100 degrees C or less.

(Lateral stretching)
The transverse stretching can be performed using a tenter. That is, the film is stretched by holding both ends in the width direction with clips and widening the film in the lateral direction. At this time, the stretching temperature can be controlled by sending wind at a desired temperature into the tenter. The stretching temperature is preferably Tg-10 ° C or higher and Tg + 60 ° C or lower, more preferably Tg-5 ° C or higher and Tg + 45 ° C or lower, and further preferably Tg or higher and Tg + 30 ° C or lower.

  By performing preheating before stretching and heat setting after stretching, the Re and Rth distribution after stretching can be reduced, and variations in orientation angles associated with bowing can be reduced. Either preheating or heat setting may be performed, but both are more preferable. These preheating and heat setting are preferably performed by holding with a clip, that is, preferably performed continuously with stretching.

  Preheating is preferably performed at 1 ° C. or higher and 50 ° C. or lower, more preferably 2 ° C. or higher and 40 ° C. or lower, more preferably 3 ° C. or higher and 30 ° C. or lower from the stretching temperature. The preheating time is preferably 1 second or longer and 10 minutes or shorter, more preferably 5 seconds or longer and 4 minutes or shorter, and even more preferably 10 seconds or longer and 2 minutes or shorter. During preheating, it is preferable to keep the width of the tenter substantially constant. Here, “substantially” refers to ± 10% of the width of the unstretched film.

  The heat setting is preferably 1 to 50 ° C., more preferably 2 to 40 ° C., more preferably 3 to 30 ° C. lower than the stretching temperature. More preferably, it is less than the stretching temperature and less than Tg. The preheating time is preferably 1 second or longer and 10 minutes or shorter, more preferably 5 seconds or longer and 4 minutes or shorter, and even more preferably 10 seconds or longer and 2 minutes or shorter. During the heat setting, it is preferable to keep the width of the tenter substantially constant. Here, “substantially” refers to 0% (the same width as the tenter width after stretching) to −10% (shrinking by 10% from the tenter width after stretching = reduced width) of the tenter width after stretching. If the width is wider than the stretched width, residual strain is likely to occur in the film, and it is not preferable because it is likely to increase the variation with time of Re and Rth.

  Thus, it is preferable that the heat setting temperature <the stretching temperature <the preheating temperature.

  The reason why the variation in orientation angle and Re, Rth can be reduced by such preheating and heat setting is as follows.

  The film is stretched in the width direction and tends to become thin (neck-in) in the orthogonal direction (longitudinal direction). For this reason, the film before and after transverse stretching is pulled and stress is generated. However, both ends in the width direction are fixed by chucks and are not easily deformed by stress, and the central portion in the width direction is easily deformed. As a result, the stress caused by the neck-in is deformed into a bow shape and bowing occurs. As a result, in-plane Re, Rth unevenness and distribution of orientation axes occur.

  In order to suppress this, if the temperature on the preheating side (before stretching) is increased and the temperature on the heat treatment (after stretching) is lowered, neck-in occurs on the high temperature side (preheating) with a lower elastic modulus and heat treatment (stretching). In later), it is hard to occur. As a result, bowing after stretching can be suppressed.

  By such stretching, variations in the width direction and the longitudinal direction of Re and Rth can both be 5% or less, more preferably 4% or less, and even more preferably 3% or less. Further, the orientation angle can be 90 ° ± 5 ° or less or 0 ° ± 5 ° or less, more preferably 90 ° ± 3 ° or less, or 0 ° ± 3 ° or less, and further preferably 90 ° ± 1 ° or less or It can be 0 ° ± 1 ° or less.

  The present invention is characterized in that such an effect can be achieved even with high-speed stretching, and the effect is remarkably exhibited even at 20 m / min or more, more preferably 25 m / min or more, and even more preferably 30 m / min or more.

(Relaxation treatment)
Furthermore, dimensional stability can be improved by performing relaxation treatment after these stretching. The thermal relaxation is preferably performed after longitudinal stretching, either after lateral stretching, or both, and more preferably after lateral stretching. The relaxation treatment may be performed online continuously after stretching, or may be performed offline after winding after stretching.

  Thermal relaxation is Tg-30 ° C or higher and Tg + 30 ° C or lower, more preferably Tg-30 ° C or higher and Tg + 20 ° C or lower, more preferably Tg-15 ° C or higher and Tg + 10 ° C or lower, 1 second or longer and 10 minutes or shorter, more preferably 5 seconds or longer and 4 seconds. Min. Or less, more preferably 10 seconds or more and 2 minutes or less, 0.1 kg / m or more and 20 kg / m or less, more preferably 1 kg / m or more and 16 kg / m or less, more preferably 2 kg / m or more and 12 kg / m or less. However, it is preferable to carry out.

<Volatile components during stretching>
In the above longitudinal stretching and lateral stretching, the volatile components (solvent, moisture, etc.) are preferably 1 wt% or less, more preferably 0.5 wt% or less, still more preferably 0.3 wt% or less with respect to the resin. Thereby, the axial shift generated during stretching can be further reduced. This is because during the stretching, in addition to the shrinkage stress acting in the direction perpendicular to the stretching, the shrinkage stress accompanying drying acts, and the bowing becomes more prominent.

(Physical properties after stretching)
It is preferable that Re and Rth of the thermoplastic film thus longitudinally stretched, laterally stretched, and longitudinally and laterally satisfied satisfy the following formulas (R-1) and (R-2).
Formula (R-1): 0 nm ≦ Re ≦ 200 nm
Formula (R-2): 0 nm ≦ Rth ≦ 600 nm
(In the formula, Re represents the in-plane retardation of the thermoplastic film, and Rth represents the thickness direction retardation of the thermoplastic film.) More preferably, Rth ≧ Re × 1.1.
180 ≧ Re ≧ 10
400 ≧ Rth ≧ 50
More preferably, Rth ≧ Re × 1.2
150 ≧ Re ≧ 20
300 ≧ Rth ≧ 100
It is.

  The angle θ formed by the film forming direction (longitudinal direction) and the slow axis of Re of the film is preferably closer to 0 °, + 90 °, or −90 °. That is, in the case of longitudinal stretching, it is preferably as close to 0 °, preferably 0 ° ± 3 °, more preferably 0 ° ± 2 °, and further preferably 0 ° ± 1 °. In the case of transverse stretching, 90 ° ± 3 ° or −90 ° ± 3 ° is preferable, more preferably 90 ° ± 2 ° or −90 ° ± 2 °, and still more preferably 90 ° ± 1 ° or −90 ° ±. 1 °.

  The variation in Re and Rth is preferably 0% to 8%, more preferably 0% to 5%, and still more preferably 0% to 3%.

  Further, the Re and Rth fluctuations under storage (Re and Rth changes before and after 500 hours at 80 ° C .: details will be described later) are preferably 0% or more and 8% or less, more preferably 0% or more and 6% or less, Preferably they are 0% or more and 4% or less.

  As for the thickness of the thermoplastic film after extending | stretching, 15 micrometers-200 micrometers are all preferable, More preferably, they are 20 micrometers-120 micrometers, More preferably, they are 30 micrometers-80 micrometers. The thickness unevenness is preferably 0% to 3% in both the longitudinal direction and the width direction, more preferably 0% to 2%, and still more preferably 0% to 1%. By using a thin film, residual strain is less likely to remain in the film after stretching, and retardation changes with time are less likely to occur. This is because when cooling after stretching, if the thickness is thick, the internal cooling is delayed compared to the surface, and residual strain due to the difference in heat shrinkage is likely to occur.

  The thermal dimensional change rate is preferably 0% or more and 0.5% or less, more preferably 0% or more and 0.3% or less, and further preferably 0% or more and 0.2% or less. The thermal dimensional change rate refers to the dimensional change when heat-treated at 80 ° C. for 5 hours.

  Moreover, the foreign material with a maximum diameter of 50 micrometers or more contained in the film of this invention is 0 piece / 3mm length x full width, and the foreign material with a maximum diameter of 20-50 micrometers or less is 30 pieces / 3mm length x full width or less. Furthermore, when the film is placed between two polarizing plates arranged in a crossed Nicol state, when the light is applied from one polarizing plate and observed from the other polarizing plate, the maximum diameter is 20 to 50 μm. Among them, the number of bright spots is 15 pieces / 3 mm length × full width or less, more preferably 10 pieces / 3 mm length × full width or less, and further preferably 5 pieces / cm 2 or less. The number and size of foreign substances can be measured by sampling a film-forming film with a length of 3 m × full width and measuring the number and size using an optical microscope.

(Processing of norbornene resin film)
The cycloolefin film of the present invention thus obtained may be used alone or in combination with a polarizing plate, and a liquid crystal layer or a layer with a controlled refractive index (low reflection layer) on these. ) Or a hard coat layer may be used. These can be achieved by the following steps.

(surface treatment)
Glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here includes a low temperature plasma treatment performed under a low pressure gas of 10 ^{−3 to} 20 Torr (0.13 to 2700 Pa). Further, plasma treatment under atmospheric pressure is also a preferable glow discharge treatment.

  A plasma-excitable gas is a gas that is plasma-excited under the above-described conditions, and examples thereof include chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Details of these are described in detail on pages 30 to 32 in the Journal of the Invention Association (Technology No. 2001-1745, issued on March 15, 2001, Invention Association). Note that, in the plasma treatment at atmospheric pressure which has been attracting attention in recent years, for example, irradiation energy of 20 to 500 KGy is used under 10 to 1000 Kev, and more preferably irradiation energy of 20 to 300 KGy is used under 30 to 500 Kev.

  Of these, glow discharge treatment, corona treatment, and flame treatment are particularly preferred. It is also preferable to provide an undercoat layer for adhesion to the functional layer. This layer may be coated after the surface treatment or may be coated without the surface treatment. Details of the undercoat layer are described on page 32 of the Japan Society for Invention and Innovation (Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention).

  These surface treatment and undercoating processes can be incorporated at the end of the film forming process, can be performed alone, or can be performed in the functional layer application process described later.

(Grant functional layer)
The functional layer described in detail on pages 32 to 45 of the Japan Occupational Technology Association (Technology No. 2001-1745, published on March 15, 2001, Japan Institute of Invention) on the cycloolefin film of the present invention. It is preferable to combine them. Among these, application of a polarizing layer (polarizing plate), application of an optical compensation layer (optical compensation sheet), and application of an antireflection layer (antireflection film) are preferable.

(A) Application of polarizing layer (preparation of polarizing plate)
(I-1) Material used Currently, a commercially available polarizing layer is obtained by immersing a stretched polymer in a solution of iodine or a dichroic dye in a bath and allowing the iodine or dichroic dye to penetrate into the binder. It is common to make it. The polarizing film is manufactured by Optiva Inc. A coating type polarizing film typified by can also be used. Iodine and dichroic dye in the polarizing film exhibit deflection performance by being oriented in the binder. As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo, amino, hydroxyl). For example, the compound as described in Invention Association public technique, public technical number 2001-1745, page 58 (issue date March 15, 2001) can be mentioned.

  As the binder for the polarizing film, either a polymer that can be crosslinked per se or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of the binder include methacrylate copolymer, styrene copolymer, polyolefin, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylolacrylamide) described in paragraph No. [0022] of JP-A-8-338913. , Polyester, polyimide, vinyl acetate copolymer, carboxymethyl cellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Among these, water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol) are preferable, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferable, and polyvinyl alcohol and modified polyvinyl alcohol are preferable. Is most preferred. It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization. The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000. The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509 and JP-A-9-316127. Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

  The lower limit of the binder thickness is preferably 10 μm. The upper limit of the thickness is preferably as thin as possible from the viewpoint of light leakage of the liquid crystal display device. It is preferably not more than a commercially available polarizing plate (about 30 μm), preferably 25 μm or less, and more preferably 20 μm or less.

  The binder of the polarizing film may be cross-linked. A polymer or monomer having a crosslinkable functional group may be mixed in the binder, or a crosslinkable functional group may be imparted to the binder polymer itself. Crosslinking can be performed by light, heat, or pH change, and a binder having a crosslinked structure can be formed. The crosslinking agent is described in US Reissue Patent 23297. Boron compounds (eg, boric acid, borax) can also be used as a crosslinking agent. The addition amount of the crosslinking agent in the binder is preferably 0.1 to 20% by mass with respect to the binder. The orientation of the polarizing element and the wet heat resistance of the polarizing film are improved.

  Even after the crosslinking reaction is completed, the unreacted crosslinking agent is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By doing in this way, a weather resistance improves.

(A-2) Stretching of polarizing layer The polarizing film is preferably dyed with iodine or a dichroic dye after stretching the polarizing film (stretching method) or rubbing (rubbing method).

  In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. Moreover, you may implement wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 10.0 times. Stretching may be performed in parallel to the MD direction (parallel stretching), or may be performed in an oblique direction (oblique stretching). These stretching operations may be performed once or divided into several times. By dividing into several times, it is possible to stretch more uniformly even at high magnification.

a) Parallel stretch method Prior to stretching, the PVA film is swollen. The degree of swelling is 1.2 to 2.0 times (mass ratio before swelling and after swelling). Thereafter, the film is stretched at a bath temperature of 15 to 50 ° C., particularly 17 to 40 ° C. in an aqueous medium bath or a dye bath for dissolving a dichroic substance while being continuously conveyed through a guide roll or the like. Stretching can be achieved by gripping with two pairs of nip rolls and increasing the conveyance speed of the subsequent nip roll to be higher than that of the previous nip roll. The draw ratio is based on the length ratio after stretching / initial state (hereinafter the same), but the preferred draw ratio is 1.2 to 3.5 times, especially 1.5 to 3.0 times from the viewpoint of the above-mentioned effects. is there. Thereafter, the film is dried at 50 ° C. to 90 ° C. to obtain a polarizing film.

b) Diagonal Stretching Method For this purpose, a method of stretching using a tenter projecting in an obliquely inclined direction as described in JP-A-2002-86554 can be used. Since this stretching is performed in the air, it is necessary to make it easy to stretch by adding water in advance. The preferred water content is 5% to 100%, more preferably 10% to 100%.

  The temperature during stretching is preferably 40 ° C to 90 ° C, more preferably 50 ° C to 80 ° C. The relative humidity is preferably 50% to 100%, more preferably 70% to 100% relative humidity, and still more preferably 80% to 100% relative humidity. The traveling speed in the longitudinal direction is preferably 1 m / min or more, more preferably 3 m / min or more.

  After the completion of stretching, the film is dried at 50 ° C to 100 ° C, more preferably 60 ° C to 90 ° C for 0.5 minutes to 10 minutes. More preferably, it is 1 minute to 5 minutes.

  The absorption axis of the polarizing film thus obtained is preferably 10 ° to 80 °, more preferably 30 ° to 60 °, and still more preferably 45 ° (40 ° to 50 °). .

(I-3) Bonding A polarizing plate is prepared by bonding the thermoplastic film after the surface treatment and a polarizing layer prepared by stretching. The laminating direction is preferably such that the casting axis direction of the thermoplastic film and the stretching axis direction of the polarizing plate are 45 °.

  The adhesive for bonding is not particularly limited, but examples thereof include PVA resins (including modified PVA such as acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group) and boron compound aqueous solution. preferable. The thickness of the adhesive layer is preferably 0.01 to 10 μm after drying, and particularly preferably 0.05 to 5 μm.

  The polarizing plate thus obtained preferably has a higher light transmittance, and preferably has a higher degree of polarization. The transmittance of the polarizing plate is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and most preferably in the range of 40 to 50% in light having a wavelength of 550 nm. . The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100% in light having a wavelength of 550 nm.

  Furthermore, the polarizing plate thus obtained can be laminated with a λ / 4 plate to produce circularly polarized light. In this case, lamination is performed so that the slow axis of λ / 4 and the absorption axis of the polarizing plate are 45 degrees. At this time, λ / 4 is not particularly limited, but more preferably has a wavelength dependency such that the lower the wavelength, the smaller the retardation. Furthermore, it is preferable to use a polarizing film having an absorption axis inclined by 20 ° to 70 ° with respect to the longitudinal direction and a λ / 4 plate made of an optically anisotropic layer made of a liquid crystalline compound.

(B) Application of optical compensation layer (production of optical compensation sheet)
The optically anisotropic layer is for compensating for the liquid crystal compound in the liquid crystal cell in the black display of the liquid crystal display device, and forms an alignment film on the thermoplastic film of the present invention. It is formed by giving.

(B-1) Alignment film An alignment film is provided on the surface-treated thermoplastic film. This film has a function of defining the alignment direction of liquid crystalline molecules. However, if the alignment state is fixed after aligning the liquid crystalline compound, the alignment film plays the role, and thus is not necessarily an essential component of the present invention. That is, it is possible to produce the polarizing plate of the present invention by transferring only the optically anisotropic layer on the alignment film in which the alignment state is fixed onto the polarizer.

  The alignment film is an organic compound (eg, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field or light irradiation is also known.

  The alignment film is preferably formed by polymer rubbing treatment. In principle, the polymer used for the alignment film has a molecular structure having a function of aligning liquid crystal molecules.

  In the present invention, in addition to the function of aligning liquid crystalline molecules, a cross-linking having a function of aligning a side chain having a crosslinkable functional group (eg, double bond) to the main chain or aligning liquid crystalline molecules. It is preferable to introduce a functional functional group into the side chain.

  As the polymer used in the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of the polymer include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylol) described in paragraph No. [0022] of JP-A-8-338913. Acrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethylcellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. . It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization. The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

  A side chain having a function of aligning liquid crystal molecules generally has a hydrophobic group as a functional group. The specific type of functional group is determined according to the type of liquid crystal molecule and the required alignment state. For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. As specific examples of these modified polyvinyl alcohol compounds, for example, paragraph numbers [0022] to [0145] in JP-A No. 2000-155216 and paragraph numbers [0018] to [0018] in JP-A No. 2002-62426 are described. [0022] and the like.

  When a side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer, or a crosslinkable functional group is introduced into a side chain having a function of aligning liquid crystalline molecules, the alignment film polymer and the optically anisotropic film The polyfunctional monomer contained in the conductive layer can be copolymerized. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer is firmly bonded by a covalent bond. Therefore, the strength of the optical compensation sheet can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.

  The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216. Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent.

  Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to the said polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high temperature and high humidity atmosphere for a long time, sufficient durability without reticulation can be obtained. May occur.

  The alignment film can be basically formed by applying the polymer, which is an alignment film forming material, on a transparent support containing a crosslinking agent, followed by heat drying (crosslinking) and rubbing treatment. As described above, the crosslinking reaction may be performed at any time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating liquid is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an alignment film and also an optically anisotropic layer reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, the pH is 4.5 to 5.5, and 5 is particularly preferable.

  The alignment film is provided on the transparent support or the undercoat layer. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above.

  For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

  When industrially implemented, this is achieved by bringing a rotating rubbing roll into contact with the film with the polarizing layer being transported. However, the roundness, cylindricity, and deflection (eccentricity) of the rubbing roll can be any. Is preferably 30 μm or less. The film wrap angle on the rubbing roll is preferably 0.1 to 90 °. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 ° or more. As for the conveyance speed of a film, 1-100 m / min is preferable. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 °. When used in a liquid crystal display device, 40 to 50 ° is preferable, and 45 ° is particularly preferable. The thickness of the alignment film thus obtained is preferably in the range of 0.1 to 10 μm.

  Next, the liquid crystalline molecules of the optically anisotropic layer are aligned on the alignment film. Thereafter, as necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer are reacted, or the alignment film polymer is crosslinked using a crosslinking agent.

  The liquid crystalline molecules used in the optically anisotropic layer include rod-like liquid crystalline molecules and discotic liquid crystalline molecules. The rod-like liquid crystal molecules and the disk-like liquid crystal molecules may be high-molecular liquid crystals or low-molecular liquid crystals, and further include those in which low-molecular liquid crystals are cross-linked and no longer exhibit liquid crystallinity.

(B-2) Rod-like liquid crystalline molecules As rod-like liquid crystalline molecules, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano substitution Phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used.

  The rod-like liquid crystalline molecule includes a metal complex. In addition, a liquid crystal polymer containing a rod-like liquid crystalline molecule in a repeating unit can also be used as the rod-like liquid crystalline molecule. In other words, the rod-like liquid crystal molecule may be bonded to a (liquid crystal) polymer.

  For rod-like liquid crystalline molecules, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemistry Vol. 22 (1994) The Chemical Society of Japan, and the 142th Committee of the Japan Society for the Promotion of Science. Described in Chapter 3.

  The birefringence of the rod-like liquid crystal molecule is preferably in the range of 0.001 to 0.7.

  The rod-like liquid crystalline molecule preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably a radically polymerizable unsaturated group or a cationically polymerizable group. Specifically, for example, the polymerizable groups described in paragraphs [0064] to [0086] of JP-A-2002-62427 are described. Group and a polymerizable liquid crystal compound.

(B-3) Discotic liquid crystalline molecules Discotic liquid crystalline molecules include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), azacrown type and phenylacetylene type macrocycles are included.

  As a discotic liquid crystalline molecule, a compound having liquid crystallinity having a structure in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule Is also included. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation. In the optically anisotropic layer formed from the discotic liquid crystalline molecules, the compound finally contained in the optically anisotropic layer does not need to be a discotic liquid crystalline molecule. Also included are compounds having a group that reacts with heat or light and, as a result, polymerized or cross-linked by reaction with heat or light, resulting in high molecular weight and loss of liquid crystallinity. Preferred examples of the discotic liquid crystalline molecules are described in JP-A-8-50206. The polymerization of discotic liquid crystalline molecules is described in JP-A-8-27284.

  In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferable, whereby the orientation state can be maintained even in the polymerization reaction. Examples thereof include compounds described in paragraphs [0151] to “0168” in JP-A No. 2000-155216.

  In the hybrid alignment, the angle between the major axis (disk surface) of the discotic liquid crystalline molecule and the surface of the polarizing film increases or decreases in the depth direction of the optically anisotropic layer and with increasing distance from the surface of the polarizing film. is doing. The angle preferably decreases with increasing distance. Further, the change in angle can be a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, or an intermittent change including an increase and a decrease. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the angle includes a region where the angle does not change, the angle only needs to increase or decrease as a whole. Furthermore, it is preferable that the angle changes continuously.

  The average direction of the major axis of the discotic liquid crystalline molecules on the polarizing film side can be generally adjusted by selecting a discotic liquid crystalline molecule or an alignment film material, or by selecting a rubbing treatment method. In addition, the major axis (disk surface) direction of the surface-side (air-side) discotic liquid crystalline molecules is generally adjusted by selecting the type of additive used together with the discotic liquid crystalline molecules or discotic liquid crystalline molecules. be able to. Examples of the additive used together with the discotic liquid crystalline molecule include a plasticizer, a surfactant, a polymerizable monomer and a polymer. The degree of change in the orientation direction of the major axis can be adjusted by selecting liquid crystal molecules and additives as described above.

(B-4) Other composition of optically anisotropic layer Along with the above liquid crystalline molecules, a plasticizer, a surfactant, a polymerizable monomer, etc. are used in combination, and the uniformity of the coating film, the strength of the film, and the liquid crystal Molecular orientation and the like can be improved. It is preferable that the compound has compatibility with the liquid crystal molecules and can change the tilt angle of the liquid crystal molecules or does not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the polymerizable group-containing liquid crystal compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline molecules.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specific examples include compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725.

  The polymer used together with the discotic liquid crystalline molecule is preferably capable of changing the tilt angle of the discotic liquid crystalline molecule.

  A cellulose ester can be mentioned as an example of a polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and preferably in the range of 0.1 to 8% by mass with respect to the liquid crystal molecule so as not to disturb the alignment of the liquid crystal molecules. It is more preferable.

  The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline molecules is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

(B-5) Formation of optically anisotropic layer The optically anisotropic layer is coated with a coating liquid containing liquid crystalline molecules and, if necessary, a polymerizable initiator and an optional component described later on the alignment film. Can be formed.

  As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

  The coating liquid can be applied by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

  The thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm.

(B-6) Fixing of alignment state of liquid crystalline molecules The aligned liquid crystalline molecules can be fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred.

  Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

  The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.5 to 5% by mass, based on the solid content of the coating solution.

  It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules.

The irradiation energy ^is preferably in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of 20~5000mJ / cm ^2, more preferably in the range of 100 to 800 mJ / cm ² . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. A protective layer may be provided on the optically anisotropic layer.

  It is also preferable to combine this optical compensation film and a polarizing layer. Specifically, the optically anisotropic layer is formed by applying the coating liquid for the optically anisotropic layer as described above to the surface of the polarizing film. As a result, without using a polymer film between the polarizing film and the optically anisotropic layer, a thin polarizing plate having a small stress (strain × cross-sectional area × elastic modulus) associated with the dimensional change of the polarizing film is produced. . When the polarizing plate according to the present invention is attached to a large liquid crystal display device, an image with high display quality can be displayed without causing problems such as light leakage.

  The tilt angle between the polarizing layer and the optical compensation layer is stretched so as to match the angle formed between the transmission axis of the two polarizing plates bonded to both sides of the liquid crystal cell constituting the LCD and the vertical or horizontal direction of the liquid crystal cell. Is preferred. A normal inclination angle is 45 °. Recently, however, devices that are not necessarily 45 ° have been developed for transmissive, reflective, and transflective LCDs, and it is preferable that the stretching direction can be arbitrarily adjusted in accordance with the design of the LCD.

(B-7) Liquid crystal display device Each liquid crystal mode in which such an optical compensation film is used will be described.

(TN mode liquid crystal display)
The TN mode liquid crystal display device is most frequently used as a color TFT liquid crystal display device, and is described in many documents. The alignment state in the liquid crystal cell in the TN mode black display is an alignment state in which the rod-like liquid crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie in the vicinity of the cell substrate.

(OCB mode liquid crystal display)
The OCB mode liquid crystal display device is a bend alignment mode liquid crystal cell in which rod-like liquid crystal molecules are aligned (symmetrically) in substantially opposite directions at the upper and lower portions of the liquid crystal cell. Liquid crystal display devices using a bend alignment mode liquid crystal cell are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode.

  Similarly to the TN mode, the liquid crystal cell in the OCB mode is in a black display, and the alignment state in the liquid crystal cell is such that the rod-like liquid crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie near the cell substrate. .

(VA mode liquid crystal display device)
The VA mode liquid crystal display device is characterized in that the rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied. (1) No voltage is applied to the VA mode liquid crystal cell. In addition to a narrowly-defined VA mode liquid crystal cell (described in JP-A-2-176625), which is sometimes aligned substantially vertically and aligned substantially horizontally when a voltage is applied, Liquid crystal cell with multi-domain mode (MVA mode) (SID97, Digest of tech. Papers 28 (1997) 845), (3) Substantially vertical alignment of rod-like liquid crystalline molecules when no voltage is applied (N-ASM mode) liquid crystal cell (described in the proceedings 58-59 (1998) of the Japanese Liquid Crystal Society) and (4 The liquid crystal cell of SURVAIVAL mode (published in LCD International 98) are included.

(IPS mode liquid crystal display)
The IPS mode liquid crystal display device is characterized in that rod-like liquid crystalline molecules are substantially aligned horizontally in a plane when no voltage is applied, and this is switched by changing the alignment direction of the liquid crystal with or without voltage application. Is the feature. Specifically, JP 2004-365951 A, JP 2004-12731 A, JP 2004-215620 A, JP 2002-221726 A, JP 2002-55341 A, JP 2003-195333 A. Those described in the publication can be used.

(Other liquid crystal display devices)
The ECB mode and the STN mode can be optically compensated in the same way as described above.

(C) Application of an antireflection layer (antireflection film)
The antireflection film generally includes a low refractive index layer which is also an antifouling layer, and at least one layer having a higher refractive index than that of the low refractive index layer (that is, a high refractive index layer and a medium refractive index layer). It is provided above.

  Colloidal metal by multilayer deposition of transparent thin films of inorganic compounds (metal oxides, etc.) with different refractive indexes by chemical vapor deposition (CVD) method, physical vapor deposition (PVD) method, sol-gel method of metal compounds such as metal alkoxides Examples include a method of forming a thin film by post-processing (ultraviolet irradiation: JP-A-9-157855, plasma processing: JP-A-2002-327310) after forming an oxide particle film.

  On the other hand, various antireflection films formed by laminating thin films in which inorganic particles are dispersed in a matrix have been proposed as antireflection films with high productivity.

  The antireflection film which consists of the antireflection layer which provided the anti-glare property which the antireflection film by application | coating as mentioned above provided the surface of the uppermost layer with the shape of a fine unevenness | corrugation is mentioned.

  The thermoplastic film of the present invention can be applied to any of the above methods, but a coating method (coating type) is particularly preferable.

(C-1) Layer structure of coating type antireflection film An antireflection film comprising a layer structure of at least a medium refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) on the substrate has the following relationship: It is designed to have a refractive index that satisfies

The refractive index of the high refractive index layer> The refractive index of the medium refractive index layer> The refractive index of the transparent support> The refractive index of the low refractive index layer Further, a hard coat layer is provided between the transparent support and the medium refractive index layer. May be. Furthermore, it may consist of a medium refractive index hard coat layer, a high refractive index layer and a low refractive index layer.

  Examples thereof include JP-A-8-122504, JP-A-8-110401, JP-A-10-300902, JP-A-2002-243906, JP-A-2000-11706, and the like.

  Other functions may be imparted to each layer, for example, an antifouling low refractive index layer or an antistatic high refractive index layer (eg, JP-A-10-206603, JP-A-2002). -243906 publication etc.) etc. are mentioned.

  The haze of the antireflection film is preferably 5% or less, more preferably 3% or less. Further, the strength of the film is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K5400.

(C-2) High Refractive Index Layer and Medium Refractive Index Layer The antireflective layer having a high refractive index is a curable film containing at least inorganic compound ultrafine particles having a high refractive index with an average particle size of 100 nm or less and a matrix binder. Consists of.

  Examples of the high refractive index inorganic compound fine particles include inorganic compounds having a refractive index of 1.65 or more, preferably those having a refractive index of 1.9 or more. Examples thereof include oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms.

  In order to obtain such ultrafine particles, the surface of the particles is treated with a surface treatment agent (for example, silane coupling agents, etc .: JP-A-11-295503, JP-A-11-153703, JP-A-2000-9908). No., anionic compound or organometallic coupling agent: Japanese Patent Laid-Open No. 2001-310432, etc., core-shell structure with high refractive index particles as a core (: Japanese Patent Laid-Open No. 2001-166104, etc.), specific dispersion (For example, Japanese Patent Laid-Open No. 11-153703, Japanese Patent No. US6210858B1, Japanese Patent Laid-Open No. 2002-27776069, etc.).

  Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films.

  Further, it is selected from a polyfunctional compound-containing composition containing at least two radically polymerizable and / or cationically polymerizable groups, an organometallic compound containing a hydrolyzable group, and a partial condensate composition thereof. At least one composition is preferred. Examples thereof include compounds described in JP-A Nos. 2000-47004, 2001-315242, 2001-31871, and 2001-296401.

  A curable film obtained from a colloidal metal oxide obtained from a hydrolyzed condensate of metal alkoxide and a metal alkoxide composition is also preferred. For example, it describes in Unexamined-Japanese-Patent No. 2001-293818.

  The refractive index of the high refractive index layer is generally 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.

  The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70.

(C-3) Low refractive index layer The low refractive index layer is formed by sequentially laminating on the high refractive index layer. The refractive index of the low refractive index layer is 1.20 to 1.55. Preferably it is 1.30-1.50.

  It is preferable to construct as the outermost layer having scratch resistance and antifouling property. As means for greatly improving the scratch resistance, imparting slipperiness to the surface is effective, and conventionally known thin film layer means such as introduction of silicon or introduction of fluorine can be applied.

  The refractive index of the fluorine-containing compound is preferably 1.35 to 1.50. More preferably, it is 1.36-1.47. The fluorine-containing compound is preferably a compound containing a crosslinkable or polymerizable functional group containing fluorine atoms in the range of 35 to 80% by mass.

  For example, paragraph numbers [0018] to [0026] of Japanese Patent Application Laid-Open No. 9-222503, paragraph numbers [0019] to [0030] of Japanese Patent Application Laid-Open No. 11-38202, and paragraph numbers of Japanese Patent Application Laid-Open No. 2001-40284. [0027] to [0028], JP-A 2000-284102, and the like.

  The silicon compound is a compound having a polysiloxane structure, preferably containing a curable functional group or a polymerizable functional group in the polymer chain and having a crosslinked structure in the film. For example, reactive silicon (eg, Silaplane (manufactured by Chisso Corporation), silanol group-containing polysiloxane (Japanese Patent Application Laid-Open No. 11-258403, etc.) and the like can be mentioned.

  The crosslinking or polymerization reaction of the fluorine-containing and / or siloxane polymer having a crosslinking or polymerizable group is carried out at the same time or after the coating composition for forming the outermost layer containing a polymerization initiator, a sensitizer, etc. It is preferable to carry out by light irradiation or heating.

  Also preferred is a sol-gel cured film in which an organometallic compound such as a silane coupling agent and a specific fluorine-containing hydrocarbon group-containing silane coupling agent are cured by a condensation reaction in the presence of a catalyst.

  For example, a polyfluoroalkyl group-containing silane compound or a partially hydrolyzed condensate thereof (Japanese Patent Laid-Open Nos. 58-142958, 58-147483, 58-147484, Japanese Patent Laid-Open Nos. 9-157582, 11) -106704), silyl compounds containing a poly "perfluoroalkyl ether" group which is a fluorine-containing long chain group (Japanese Patent Application Laid-Open Nos. 2000-117902, 2001-48590, 2002) 53804), and the like.

  The low refractive index layer has an average primary particle diameter of 1 to 150 nm such as a filler (for example, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)) as an additive other than the above. Low refractive index inorganic compounds, organic fine particles described in paragraphs [0020] to [0038] of JP-A-11-3820, etc.), silane coupling agents, slip agents, surfactants, and the like can be contained.

  When the low refractive index layer is located below the outermost layer, the low refractive index layer may be formed by a vapor phase method (vacuum deposition method, sputtering method, ion plating method, plasma CVD method, etc.). The coating method is preferable because it can be manufactured at a low cost.

  The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and most preferably 60 to 120 nm.

(C-4) Hard coat layer The hard coat layer is provided on the surface of the transparent support in order to impart physical strength to the antireflection film. In particular, it is preferably provided between the transparent support and the high refractive index layer.

  The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of a light and / or heat curable compound.

  The curable functional group is preferably a photopolymerizable functional group, and the hydrolyzable functional group-containing organometallic compound is preferably an organic alkoxysilyl compound.

  Specific examples of these compounds are the same as those exemplified for the high refractive index layer.

  Specific examples of the constituent composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908, and International Publication WO0 / 46617.

  The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described for the high refractive index layer.

  The hard coat layer can also serve as an antiglare layer (described later) provided with particles having an average particle size of 0.2 to 10 μm to provide an antiglare function (antiglare function).

  The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm.

  The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

(C-5) Forward scattering layer The forward scattering layer is provided in order to give a viewing angle improvement effect when the viewing angle is inclined in the vertical and horizontal directions when applied to a liquid crystal display device. By dispersing fine particles having different refractive indexes in the hard coat layer, it can also serve as a hard coat function.

  For example, Japanese Patent Laid-Open No. 11-38208 specifying a forward scattering coefficient, Japanese Patent Laid-Open No. 2000-199809 having a relative refractive index of a transparent resin and fine particles in a specific range, and Japanese Patent Laid-Open No. 2002 specifying a haze value of 40% or more. -107512 gazette etc. are mentioned.

(C-6) Other layers In addition to the above layers, a primer layer, an antistatic layer, an undercoat layer, a protective layer, and the like may be provided.

(C-7) Coating method Each layer of the antireflection film is formed by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating, a micro gravure method or an extrusion coating method (US patent). No. 2,681,294) can be formed by coating.

(C-8) Anti-glare function The antireflection film may have an anti-glare function that scatters external light. The antiglare function is obtained by forming irregularities on the surface of the antireflection film. When the antireflection film has an antiglare function, the haze of the antireflection film is preferably 3 to 30%, more preferably 5 to 20%, and most preferably 7 to 20%.

  As a method for forming irregularities on the surface of the antireflection film, any method can be applied as long as these surface shapes can be sufficiently maintained. For example, a method of forming irregularities on the film surface using fine particles in the low refractive index layer (for example, JP 2000-271878 A), a lower layer of the low refractive index layer (high refractive index layer, medium refractive index layer) Alternatively, a small amount (0.1 to 50% by mass) of relatively large particles (particle size 0.05 to 2 μm) is added to the hard coat layer to form a surface uneven film, and these shapes are maintained thereon. A method of providing a low refractive index layer (for example, JP 2000-281410 A, JP 2000-95893 A, JP 2001-100004 A, 2001-281407, etc.), an uppermost layer (antifouling layer) A method of physically transferring the uneven shape onto the surface after coating (for example, as an embossing method, Japanese Patent Laid-Open Nos. 63-278839, 11-183710, 2000-275401) It includes equal forth) and the like.

  The present invention will be described more specifically with reference to the following examples. The materials, production conditions, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

  The table of FIG. 4 shows the flow value of the outer layer, the flow value of the core layer, the layer ratio of the core layer to the outer layer, the film thickness, the surface roughness, and oxygen for Examples 1 to 24 and Comparative Examples 1 to 4 of the present invention. Concentration, inert gas temperature, film forming method, film strength and comprehensive evaluation are summarized in a table. Evaluation items were evaluated by film strength and comprehensive evaluation.

(Film strength)
A sample of 15 mm × 250 mm was conditioned at 23 ° C. and relative humidity of 65% for 2 hours, and an initial sample length of 100 mm and a tensile speed of 200 according to ISO1184-1983 using a Tensilon tensile tester (RTA-100, Orientec Corp.). The breaking elongation was evaluated at ± 5 mm / min.

  When the elongation at break was 10% or more, the evaluation was made in three stages, with ◯ when it was 5% or more and less than 10%, and x when it was less than 5%.

(Comprehensive evaluation)
In the overall evaluation, in the film quality evaluation, the level that satisfies the manufacturing quality level is ◎, the level that satisfies the manufacturing quality is ◯, the quality that is not a problem of actual use but the level that is not the product quality is △, the problem of actual use The evaluation was made in four stages with x indicating a level of failure.

Examples 1 to 24, at least one surface of the core layer and a core layer comprising a resin composition mainly composed of a norbornene resin having a flow value of less than ^{3 cm} 3/10 minutes or more 15cm ^3/10 min at 260 ° C. in, and a outer layer comprising a resin composition mainly composed of a norbornene resin having a flow value of less than 15cm ^3/10 minutes or more 45cm ^3/10 min at 260 ° C.. Therefore, evaluation more than (triangle | delta) was obtained in comprehensive evaluation.

  On the other hand, Comparative Examples 1 to 4 were evaluated as x in the comprehensive evaluation because either the core layer or the outer layer was outside the above range.

  In addition, Examples 1-23 employ | adopted the touch roll method, and Example 24 employ | adopted the casting drum method.

In Examples 1-3, and Comparative Examples 1 and 2, the flow value of the core layer is fixed at ^{8 cm} 3/10 min, changing the flow value of the outer layer. The ratio of the thickness of the core layer to the total thickness of the outer layers was 1.5: 1, and the film thickness was 80 μm. When the flow value of the outer layer is a 32cm ^3/10 minutes, as a comprehensive evaluation ◎ was obtained.

In Examples 4-6 and Comparative Examples 3-4, the flow value of the outer layer is fixed with 32cm ^3/10 minutes, changing the flow value of the core layer. The ratio of the thickness of the core layer to the total thickness of the outer layers was 5: 1, the film thickness was 80 μm in Comparative Example 3, and 60 μm in Examples 4 to 6 and Comparative Example 4. When the flow values of the core layer is 8 cm ^3/10 min, as a comprehensive evaluation ◎ was obtained.

In Example 7-11, the flow value of the core layer ^{8 cm} 3/10 min, a flow value of the outer layer is fixed with 32cm ^3/10 minutes, and the core layer thickness was varied the ratio of the total thickness of the outer layer . When the ratio of the thickness of the core layer to the total thickness of the outer layer was 2.5: 1 (Example 9), ◎ was obtained as a comprehensive evaluation. Further, when the ratio of the core layer thickness to the total thickness of the outer layers was 25: 1 (Example 11), the overall evaluation was Δ.

  In Examples 12 to 14, the ratio of the core layer thickness to the total thickness of the outer layers was 10: 1, and the film thickness was changed. As a comprehensive evaluation, ◎ was obtained in all cases.

  In Example 15, the outer layer was provided only on one side of the core layer. Δ was obtained as a comprehensive evaluation.

In Example 16-19, the flow value of the core layer ^{8 cm} 3/10 min, a flow value of the outer layer is fixed with 32cm ^3/10 minutes, and the core layer thickness, the ratio of the total thickness of the outer layer 10: 1 And fixed. The film thickness was 80 μm. The oxygen concentration around the die was changed. When the oxygen concentration was 6% (Example 16), ◎ was obtained as a comprehensive evaluation. On the other hand, when the oxygen concentration was 15% (Example 18) and 20% (Example 19), which were larger than 10%, the overall evaluation was Δ.

In Example 20-23, the flow value of the core layer ^{8 cm} 3/10 min, a flow value of the outer layer is fixed with 32cm ^3/10 minutes, and the core layer thickness, the ratio of the total thickness of the outer layer 10: 1 And fixed. The film thickness was 60 μm. The oxygen concentration around the die was 6%. The temperature of the inert gas was changed. When the temperature of the inert gas was 100 ° C. (Example 21), the overall evaluation was “◎”. When the temperature of the inert gas was 280 ° C. (Example 22), the overall evaluation was “good”. On the other hand, when the temperature of the inert gas was 50 ° C. (Example 20) and 300 ° C. (Example 23), which were outside the range of 100 to 280 ° C., the overall evaluation was Δ.

In Example 24, a flow value of the core layer ^{8 cm} 3/10 min, a flow value of the outer layer is fixed with 32cm ^3/10 minutes, and the core layer thickness, the ratio of the total thickness of the outer layer 10: Fixed 1 did. The oxygen concentration around the die was 6%, and the film forming method was a casting drum method. The overall evaluation was Δ.

  If the die stripe was 50 nm or less, an overall evaluation of Δ or more was obtained. Further, even when the surface roughness (Ra) was 0.05 μm or less, the evaluation of Δ or more was obtained as the overall evaluation.

  Regarding the film forming method, it can be understood that good results can be obtained in the comprehensive evaluation by either the touch roll method or the casting drum method.

Configuration diagram of a manufacturing apparatus to which the present invention is applied Schematic showing the configuration of the extruder Explanatory drawing which shows the state by which film-like resin was coextruded from die | dye Table showing the results of the examples

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Manufacturing apparatus, 12 ... 1st norbornene-type resin, 12 '... 2nd norbornene-type resin, 12A ... Film-like resin, 14, 14' ... Extruder, 16 ... Die, 16A ... Discharge port, 18 ... 1st 1 cooling roller, 20 ... second cooling roller, 22 ... third cooling roller, 24 ... peeling roller, 26 ... winding machine, 28 ... touch roll, 30 ... piping, 32,34 ... supply pipe, 44 ... Cylinder, 46 ... Screw shaft, 48 ... Flight, 50 ... Single screw, 52 ... Supply port, 54 ... Discharge port

Claims (11)

A co-extruded norbornene-based resin film,
A core layer comprising a resin composition mainly composed of a norbornene resin having a flow value of less than ^{3 cm} 3/10 minutes or more 15cm ^3/10 min at 260 ° C.,
On at least one surface of the core layer, norbornene resin film comprising an outer layer comprising a resin composition mainly composed of a norbornene resin having a flow value of less than 15cm ^3/10 minutes or more 45cm ^3/10 min at 260 ° C. .   The norbornene-based resin film according to claim 1, wherein the ratio of the thickness of the core layer to the total thickness of the outer layer is 20: 1 to 1: 1.   The norbornene resin film according to claim 1 or 2, wherein the norbornene resin film has a die depth or height of 50 nm or less and a surface Ra of 0.05 µm or less.   The norbornene resin film according to claim 1, wherein the norbornene resin film has a thickness of 20 to 300 μm.   A polarizing plate comprising at least one layer of the norbornene-based resin film according to claim 1.   An optical compensation film for a liquid crystal display plate, wherein the norbornene resin film according to claim 1 is used as a base material.   An antireflection film, wherein the norbornene resin film according to claim 1 is used as a base material. A step of melting the first resin composition composed mainly of a norbornene resin having a flow value of less than ^{3 cm} 3/10 minutes or more 15cm ^3/10 min at 260 ° C.,
A step of melting the second resin composition whose main component is a norbornene resin having a flow value of less than 15cm ^3/10 minutes or more 45cm ^3/10 min at 260 ° C.,
Coextruding a film-form norbornene-based resin having the first resin composition as a core layer and the second resin composition as an outer layer from a discharge port of a die;
And a step of cooling and solidifying the film-form norbornene resin coextruded, and a method for producing a norbornene resin film.   The method for producing a norbornene-based resin film according to claim 8, wherein the oxygen concentration around the discharge port of the die is 10% or less.   The method for producing a norbornene-based resin film according to claim 9, wherein an inert gas heated to 100 to 280 ° C is blown around the discharge port of the die so that the oxygen concentration around the discharge port is 10% or less.   The method for producing a norbornene-based resin film according to any one of claims 8 to 10, wherein the cooling and solidifying step is performed by a touch roll method.

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