JP2006051804A - Thermoplastic film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a thermoplastic film capable of enhancing an optical property of the thermoplastic film obtained by stretch and to provide the thermoplastic film. <P>SOLUTION: A lateral stretch process part 30 laterally stretching the thermoplastic film 16 comprises a preheating zone T1, lateral stretch zones T2 and T3, and cooling zones T4 and T5. The temperatures of the precesses after the lateral stretch zone T3 (the cooling zones T4 and T5) are kept at temperatures of not higher than the glass transition temperature Tg. The temperature of the preheating zone T1 is higher than that of the cooling zone T4, and is set at the temperature from -10°C to +30°C with respect to the temperature of the lateral stretch zones T2 and T3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermoplastic film and a manufacturing method thereof, and more particularly to a thermoplastic film used in a liquid crystal display device and a manufacturing method thereof.

  Conventionally, a thermoplastic film has been stretched to develop in-plane retardation (Re) and retardation in the thickness direction (Rth), and used as a phase difference film for liquid crystal display elements to increase the viewing angle. ing.

  As a method of stretching such a thermoplastic film, a method of stretching in the longitudinal (longitudinal) direction (longitudinal stretching), a method of stretching in the transverse (width) direction (transverse stretching), or longitudinal stretching and lateral stretching in order. The method to perform (sequential biaxial stretching) is mentioned.

  Among these, in sequential biaxial stretching, the film is first heated to a glass transition temperature (Tg) or more between two or more pairs of nip rolls, and the conveyance speed on the outlet side is made faster than the conveyance speed of the nip roll on the inlet side. Stretch in the machine direction. Subsequently, using a tenter, the film is heated while holding both ends of the film with clips, and then stretched in the width direction. At this time, if a straight line is drawn along the width direction on the surface of the film before entering the tenter, this straight line is deformed in the tenter and deformed into a concave shape after the film is stretched. To do. This phenomenon is called bowing and is known as a factor that makes the physical properties in the width direction uneven.

  The reason why the bowing phenomenon occurs is that the binding force by the clip is weak at the center of the film with respect to the end portion held by the clip, and a delay occurs during continuous stretching. In the simultaneous biaxial stretching method, bowing generally occurs when the film width is increased in the transverse direction.

In order to solve such a problem, various countermeasures have been proposed conventionally. For example, Patent Document 1 proposes to insert a cooling zone between the stretching process and the heat setting process. According to this cited document 1, bowing can be reduced to some extent.
Japanese Patent Laid-Open No. 4-74635

  However, the film of Cited Document 1 still has a large bowing for use as a retardation plate incorporated in a liquid crystal display element, and the uniformity of Re, Rth, and orientation angle is insufficient. Therefore, when the film of the cited document 1 is used as a retardation film of a liquid crystal display element, there is a problem that unevenness occurs in the liquid crystal display screen.

  This invention is made | formed in view of such a situation, and it aims at providing the manufacturing method of the thermoplastic film which can improve the optical characteristic of the thermoplastic film obtained by extending | stretching, and the thermoplastic film.

  In order to achieve the above object, the invention according to claim 1 is a method for producing a thermoplastic film produced by stretching a thermoplastic film in the transverse direction. It is characterized by being carried out at a temperature of

  The inventors of the present invention have made extensive studies in view of the above problems, and as a result, have found that the occurrence of bowing depends on the temperature before and after stretching (particularly the temperature after stretching). Specifically, it has been found that if the step after stretching is maintained at a glass transition temperature Tg or less, the occurrence of bowing can be prevented. As a process after stretching, a fixing zone has been conventionally provided. In this fixing zone, the film was crystallized and held at a temperature equal to or higher than Tg. The present inventors have found that the existence of this fixed zone has an adverse effect on the occurrence of Boeing. The invention according to claim 1 is based on such knowledge, and since the step after stretching is performed while maintaining the temperature at Tg or lower, the occurrence of bowing can be prevented.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the film temperature before stretching is higher than the film temperature after stretching.

  According to a third aspect of the present invention, in order to achieve the above object, in the method for producing a thermoplastic film produced by stretching a thermoplastic film in the transverse direction, the film temperature before stretching is higher than the film temperature after stretching. It is also characterized by high.

  According to invention of Claim 2 and 3, the distortion of the reverse direction generate | occur | produced in the film at the time of extending | stretching by starting the film temperature before extending | stretching higher than the film temperature after extending | stretching (convex distortion). Can be increased. Therefore, the occurrence of the final concave bowing distortion can be more effectively suppressed.

  Invention of Claim 4 in invention of any one of Claims 1-3 WHEREIN: While preheating the thermoplastic film before the said extending | stretching, the zone temperature at the time of this preheating is set with respect to the zone temperature at the time of the said extending | stretching, It is characterized by being held at −10 ° C. or higher and + 30 ° C. or lower. According to the fourth aspect of the present invention, the film can be reliably stretched by defining the zone temperature during preheating within the above range with respect to the zone temperature during stretching.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the stretching is at least 1 time to 2.5 times in a state where both ends in the width direction of the thermoplastic film are held by clips. It is characterized by stretching in the following. The above-described invention can more effectively suppress the occurrence of bowing when the film end is held by a clip and stretched 1 to 2.5 times.

  In order to achieve the above object, the invention according to claim 6 has an orientation angle of 0 ° ± 5 ° or 90 ° ± 5 °, a bowing strain of 10% or less, an in-plane retardation (Re ) Is 0 nm to 500 nm, and the thickness direction retardation (Rth) is 30 nm to 500 nm. The thermoplastic film having such characteristics can be manufactured by the above-described manufacturing method and has excellent optical characteristics.

  According to a seventh aspect of the present invention, in the sixth aspect of the invention, the retardations Re and Rth each have a variation in the width direction and the longitudinal direction of 5% or less, and the orientation angle varies in the width direction and the longitudinal direction, respectively. It is characterized by being 5 ° or less. Therefore, in the film according to claim 7, the retardation and the orientation angle are uniform in the width direction and the longitudinal direction, and there is very little variation in the optical characteristics in the plane.

  The invention according to claim 8 is the invention according to claim 6 or 7, wherein the thermoplastic film is a cellulose acylate film or a saturated norbornene film. Cellulose acylate films and saturated norbornene films are particularly effective because they are films that do not need to be crystallized after stretching.

  The invention according to claim 9 is the invention according to claim 8, wherein in the cellulose acylate film, the acylate group has a substitution degree of 2.5 ≦ A + B <3.0, 1.25 ≦ B <3.0, (A : Substitution degree of acetate group, B: Sum of substitution degree of propionate group, butyrate group, pentanoyl group, hexanoyl group). A film satisfying such a degree of substitution is characterized by a low melting point, easy stretching, and excellent moisture resistance. A film satisfying such a substitution degree is particularly effective because it does not need to be crystallized.

  A tenth aspect of the present invention is a polarizing plate in which at least one layer of the cellulose acylate film according to the eighth or ninth aspect is laminated.

  An eleventh aspect of the present invention is an optical compensation film for a liquid crystal display panel, wherein the cellulose acylate film according to the eighth and ninth aspects is used as a substrate.

  An invention according to claim 12 is an antireflection film characterized in that the cellulose acylate film according to claims 8 and 9 is used as a substrate.

  According to the present invention, unevenness in Re, Rth, and orientation angle when stretched can be reduced, and good optical characteristics can be obtained over the entire film surface. Therefore, a uniform display can be obtained in a plane when used by being incorporated in a liquid crystal display element.

  Preferred embodiments of a thermoplastic film and a method for producing the same according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows an example of a schematic configuration of a film manufacturing apparatus. As shown in the figure, the film manufacturing apparatus mainly includes a film forming process unit 10, a longitudinal stretching process unit 20, a transverse stretching process unit 30, and a winding process unit 40.

  In the film forming process section 10, a thermoplastic resin is extruded into a sheet form from a die 12 of an extruder, and cast onto a rotating cooling drum 14 to obtain a rapidly cooled and solidified film 16. The film 16 is peeled off from the cooling drum 14, sent in order to the longitudinal stretching process unit 20 and the lateral stretching process unit 30 and stretched, and then wound up in a roll shape by the winding process unit 40.

The film 16 is stretched in order to orient the molecules in the film 16 and develop in-plane retardation (Re) and thickness direction retardation (Rth). Here, the retardations Re and Rth are obtained by the following equations.
Re (nm) = | n (MD) −n (TD) | × T (nm)
Rth (nm) = | {(n (MD) + n (TD)) / 2} −n (TH) | × T (nm)
In the formula, n (MD), n (TD), and n (TH) represent the refractive index in the longitudinal direction, the width direction, and the thickness direction, and T represents the thickness in nm.

  First, the film 16 is longitudinally stretched in the longitudinal direction in the longitudinal stretching step 20. In the longitudinal stretching process section 20, after the film 16 is preheated, the film 16 is heated and wound around the two nip rolls 22 and 24. The exit-side nip roll 24 transports the film 16 at a transport speed faster than that of the entrance-side nip roll 22, whereby the film 16 is stretched in the longitudinal direction.

  The preheating temperature in the longitudinal stretching step 20 is preferably Tg-40 ° C or higher and Tg + 60 ° C or lower, more preferably Tg-20 ° C or higher and Tg + 40 ° C or lower, and further preferably Tg or higher and Tg + 30 ° C or lower. In addition, the stretching temperature of the longitudinal stretching step 20 is preferably Tg or more and Tg + 60 ° C., more preferably Tg + 2 ° C. or more and Tg + 40 ° C. or less, and further preferably Tg + 5 ° C. or more and Tg + 30 ° C. or less. The stretching ratio in the machine direction is preferably 1.01 to 3 times, more preferably 1.05 to 2.5 times, and even more preferably 1.1 to 2 times.

  The longitudinal stretching is preferably carried out with the solvent remaining in the film 16 being 3 wt% or less, more preferably 2 wt% or less, and even more preferably 1 wt% or less. This is because in the presence of the residual solvent, the orientation of molecules in the film 16 is easily relaxed over time, and Re and Rth are likely to change over time.

  In the present invention, the longitudinal stretching may be omitted and only the lateral stretching described later may be performed. Moreover, you may perform simultaneous biaxial stretching which performs longitudinal stretching and lateral stretching simultaneously.

  The film 16 stretched in the longitudinal direction is sent to the transverse stretching step section 30 and is stretched in the width direction. In the lateral stretching step 30, for example, a tenter is used. The tenter grips both ends of the film 16 in the width direction with clips and stretches in the lateral direction. By this transverse stretching, the retardation Rth can be further increased.

  FIG. 2 is a schematic diagram showing a zone configuration of the transverse stretching process section 30. In the drawing, the transverse stretching process section 30 is composed of a number of zones that can be individually controlled by hot air and divided by a windshield curtain 32. From the entrance, a preheating zone T1, transverse stretching zones T2, T3, and a cooling zone are formed. T4 and T5 are arranged.

  Here, the stretching temperature of the transverse stretching zones T2 and T3 is preferably Tg-10 ° C. or higher and Tg + 50 ° C. or lower, more preferably Tg−5 ° C. or higher and Tg + 40 ° C. or lower, and further preferably Tg or higher and Tg + 30 ° C. or lower.

  The preheating temperature in the preheating zone T1 is preferably Tg−20 ° C. or more and Tg + 80 ° C. or less, more preferably Tg−15 ° C. or more and Tg + 70 ° C. or less, and further preferably Tg−10 ° C. or more and Tg + 60 ° C. or less. That is, it is preferably −10 ° C. or higher and + 30 ° C. or lower with respect to the temperature of the transverse stretching zones T2 and T3.

  The temperature of the cooling zone T4 immediately after stretching is preferably Tg or less, preferably Tg-5 ° C or less, more preferably Tg-10 ° C or less, and lower than the preheating temperature. Then, in all the processes after the transverse stretching zones T2 and T3 (that is, in the cooling zones T4 and T5 and the winding process unit 40 in this embodiment), the zone temperature is kept below Tg.

  Note that a relaxation zone may be provided before the cooling zone T4 to gradually cool it. Also in this case, the temperature after the transverse stretching zones T2, T3 is kept below Tg.

  In addition, the draw ratio in the transverse drawing is preferably 1.0 to 3 times, more preferably 1.05 to 2.8 times, and even more preferably 1.1 to 2.5 times. It is also preferable to relax in the longitudinal and / or lateral direction after this lateral stretching. Thereby, the distribution of the slow axis in the width direction can be reduced.

  The stretched thermoplastic film 16 has a retardation Re of 0 nm to 500 nm, preferably 10 nm to 400 nm, more preferably 15 nm to 300 nm. The retardation Rth is preferably 30 nm to 500 nm, more preferably 50 nm to 400 nm, and still more preferably 70 nm to 350 nm. Among these, those satisfying Re ≦ Rth are more preferable, and those satisfying Re × 2 ≦ Rth are more preferable. In order to realize such a high Rth and low Re, it is preferable to stretch the longitudinally stretched material in the transverse (width) direction as described above. In other words, the difference in orientation between the vertical direction and the horizontal direction becomes the difference in retardation (Re) in the plane, but by stretching in the horizontal direction, which is the orthogonal direction in addition to the vertical direction, the difference in vertical and horizontal orientation is reduced. The surface orientation (Re) can be reduced by reducing the size. On the other hand, since the area magnification increases by stretching in addition to the length, the orientation in the thickness direction increases as the thickness decreases, and Rth can be increased.

  Further, it is preferable that the variation of Re and Rth depending on the location in the width direction and the longitudinal direction is 5% or less, more preferably 4% or less, and further preferably 3% or less. Further, the orientation angle is preferably 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 is preferable to be 0 ° ± 1 ° or less. These can reduce bowing by performing stretching as in the present invention, and the straight line drawn along the width direction on the surface of the film 16 before entering the tenter is deformed into a concave shape after the stretching is completed. The bowing strain obtained by dividing the deviation by the width can be 10% or less, more preferably 5% or less, and even more preferably 3% or less.

  Next, the operation of the transverse stretching process unit 30 configured as described above will be described.

  FIG. 3 is an explanatory view for explaining the operation of the present invention, and FIG. 3 (A) shows the situation of occurrence of bowing in the present invention. FIG. 3B shows a bowing occurrence state in a comparative example in which a heat fixing zone (temperature> Tg) is provided between the transverse stretching zone and the cooling zone.

  As shown in FIG. 3B, in the case of the comparative example, a convex distortion is formed at the initial stage of the transverse stretching zone, the distortion is reversed in the middle, and a concave bowing is formed in the heat setting zone. This is because the film 16 is heated to Tg or more in the heat setting zone, and when the both ends of the film 16 are pulled in a state where the film 16 is easily deformed, a large bowing distortion is generated. This bowing distortion becomes maximum at the initial stage of the heat setting zone, passes through the heat setting zone as it is, and the bowing remains.

  On the other hand, in this embodiment, immediately after the end of the transverse stretching zone T3, a cooling zone T4 whose temperature is controlled to Tg or less is provided. For this reason, the film 16 that has finished the transverse stretching zone T3 is less likely to be deformed. Therefore, if a straight line in the width direction is drawn on the surface of the film 16, the deformation of the film 16 is finished before the convex bowing becomes concave as shown in FIG. It is held in the state. And since it was made to hold | maintain at the temperature below Tg at the process after transverse stretching zone T2, T3, it can maintain in the state which suppressed generation | occurrence | production of the bowing. Thereby, the film 16 which prevented generation | occurrence | production of a bowing can be manufactured.

  In the present embodiment, the temperature of the preheating zone T1 is set to be higher than the temperatures of the cooling zones T4 and T5. Thus, if the temperature of the preheating zone T1 is set high, the convex distortion with respect to the traveling direction of the film 16 becomes large at the initial stage of the transverse stretching zone T2. By increasing the convex distortion, the concave bowing distortion generated in the cooling zone T4 can be minimized. Therefore, the occurrence of bowing distortion can be more effectively suppressed.

  As described above, according to the present embodiment, the temperatures of the zones (T1, T4, T5) before and after the transverse stretching zones T2, T3 are appropriately controlled, so that the occurrence of bowing distortion is effectively suppressed. be able to. Thereby, Re, Rth, an orientation angle, and the magnitude | size of a bowing distortion can be manufactured in the range mentioned above, and the thermoplastic film excellent in the optical characteristic can be obtained.

  Hereinafter, the resin, film forming method, and film processing method suitable for the present invention will be described.

(1) Thermoplastic resin Although the thermoplastic resin which performs the extending | stretching mentioned above is not restrict | limited, A cellulose acylate film and a saturated norbornene-type film are more preferable. These are because they have moderate Re and Rth developability due to stretching, and are excellent in uneven stretching. Hereinafter, the cellulose acylate resin and the saturated norbornene resin will be described.

(Cellulose acylate resin)
The cellulose acylate used in the present invention preferably has the following characteristics. The acylate group has the following substitution degree,
2.5 ≦ A + B ≦ 3.0
1.25 ≦ B ≦ 3
A cellulose acylate film characterized by satisfying the above (A is the substitution degree of acetate group, B is the total substitution degree of propionate group, butyrate group, pentanoyl group, hexanoyl group). More preferable substitution degree is when 1/2 or more of B is a propionate group.
2.6 ≦ A + B ≦ 2.95
2.0 ≦ B ≦ 2.95
And when less than 1/2 of B is a propionate group,
2.6 ≦ A + B ≦ 2.95
1.3 ≦ B ≦ 2.5. Further preferred substitution degree is when 1/2 or more of B is a propionate group,
2.7 ≦ A + B ≦ 2.95
2.4 ≦ B ≦ 2.9
And when less than 1/2 of B is a propionate group,
2.7 ≦ A + B ≦ 2.95
1.3 ≦ B ≦ 2.0.

  The present invention is characterized in that the substitution degree of the acetate group is reduced and the sum of the substitution degree of the propionate group, butyrate group, pentanoyl group, and hexanoyl group is increased. As a result, unevenness of elongation is difficult to occur during stretching, unevenness of Re and Rth are difficult to occur, crystal melting temperature (Tm) can be lowered, and yellowing caused by thermal decomposition of molten film is suppressed. You can also. These effects can be achieved by using as large a substituent as possible. However, if it is too large, the glass transition temperature (Tg) and the elastic modulus are excessively lowered, which is not preferable. For this reason, propionate groups, butyrate groups, pentanoyl groups and hexanoyl groups which are larger than acetyl groups are preferred, propionate groups and butyrate groups are more preferred, and butyrate groups are more preferred.

  The basic principle of these cellulose acylate synthesis methods is described in Mita et al., Wood Chemistry, 180-190 (Kyoritsu Shuppan, 1968). A typical synthesis method is a liquid phase acetylation method using a carboxylic acid anhydride-acetic acid-sulfuric acid catalyst. Specifically, cellulose raw materials such as cotton linter and wood pulp are pretreated with an appropriate amount of acetic acid, and then put into a pre-cooled carboxylated mixed solution to be esterified to complete cellulose acylate (2nd, 3rd and 6th). The total degree of acyl substitution at the position is approximately 3.00). The carboxylated mixed solution generally contains acetic acid as a solvent, carboxylic anhydride as an esterifying agent, and sulfuric acid as a catalyst. The carboxylic anhydride is usually used in a stoichiometric excess over the sum of the cellulose that reacts with it and the water present in the system. After completion of the acylation reaction, a neutralizing agent (for example, calcium, magnesium, iron, aluminum or zinc) is used for hydrolysis of excess carboxylic anhydride remaining in the system and neutralization of a part of the esterification catalyst. Of carbonate, acetate or oxide). Next, the obtained complete cellulose acylate is saponified and aged by maintaining it at 50 to 90 ° C. in the presence of a small amount of an acetylation reaction catalyst (generally, remaining sulfuric acid) to obtain the desired degree of acyl substitution and polymerization. The cellulose acylate having a degree is changed. When the desired cellulose acylate is obtained, the catalyst remaining in the system is completely neutralized with a neutralizing agent as described above, or in water or dilute sulfuric acid without neutralization. The cellulose acylate solution is added (or water or dilute sulfuric acid is added into the cellulose acylate solution) to separate the cellulose acylate, and the cellulose acylate is obtained by washing and stabilizing treatment.

  The degree of polymerization of the cellulose acylate preferably used in the present invention is a viscosity average degree of polymerization of 200 to 700, preferably 250 to 550, more preferably 250 to 400, and particularly preferably a viscosity average degree of polymerization of 250 to 350. The average degree of polymerization can be measured by Uda et al.'S intrinsic viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Society, Vol. 18, No. 1, pages 105-120, 1962). Further details are described in JP-A-9-95538.

  Such adjustment of the degree of polymerization can also be achieved by removing low molecular weight components. When the low molecular component is removed, the average molecular weight (degree of polymerization) increases, but the viscosity becomes lower than that of normal cellulose acylate, which is useful. The removal of the low molecular component can be carried out by washing the cellulose acylate with an appropriate organic solvent. Further, the molecular weight can be adjusted by a polymerization method. For example, when manufacturing a cellulose acylate with few low molecular components, it is preferable to adjust the sulfuric acid catalyst amount in an acetylation reaction to 0.5-25 mass parts with respect to 100 weight of cellulose. When the amount of the sulfuric acid catalyst is within the above range, cellulose acylate that is preferable in terms of molecular weight distribution (uniform molecular weight distribution) can be synthesized.

  The cellulose acylate used in the present invention preferably has a weight average molecular weight Mw / number average molecular weight Mn ratio of 1.5 to 5.5, particularly preferably 2.0 to 5.0, and still more preferably. Is 2.5 to 5.0, more preferably 3.0 to 5.0 cellulose acylate is preferably used.

  These cellulose acylates may be used alone or in combination of two or more. Further, a polymer component other than cellulose acylate may be appropriately mixed. The polymer component to be mixed is preferably one having excellent compatibility with the cellulose ester, and the transmittance when formed into a film is preferably 80% or more, more preferably 90% or more, and further preferably 92% or more.

  In the present invention, the crystal melting temperature (Tm) of cellulose acylate can be lowered by adding a plasticizer to cellulose acylate. The molecular weight of the plasticizer used in the present invention is not particularly limited, and may be a low molecular weight or a high molecular weight. Examples of the plasticizer include phosphate esters, alkylphthalylalkyl glycolates, carboxylic acid esters, and fatty acid esters of polyhydric alcohols. These plasticizers may be solid or oily. That is, the melting point and boiling point are not particularly limited. When performing melt film formation, those having non-volatility can be particularly preferably used.

  Specific examples of the phosphate ester include, for example, triphenyl phosphate, tributyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, trioctyl phosphate, trinaphthyl phosphate, trixylyl phosphate, tris ortho-biphenyl phosphate, cresyl phenyl phosphate, Examples include octyl diphenyl phosphate, biphenyl diphenyl phosphate, and 1,4-phenylene tetraphenyl phosphate. Moreover, it is also preferable to use the phosphate ester type plasticizer described in claims 3 to 7 of JP-T-6-501040.

  Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.

  Examples of carboxylic acid esters include phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate and diethyl hexyl phthalate, and citrate esters such as acetyl trimethyl citrate, acetyl triethyl citrate and acetyl tributyl citrate. , Adipates such as dimethyl adipate, dibutyl adipate, diisobutyl adipate, bis (2-ethylhexyl) adipate, diisodecyl adipate, bis (butyl diglycol adipate), aromatics such as tetraoctyl pyromellitate, trioctyl trimellitate Polycarboxylic acid esters, dibutyl adipate, dioctyl adipate, dibutyl sebacate, dioctyl sebacate, diethyl azelate Dibutyl azelate, aliphatic, such as dioctyl azelate polycarboxylic acid esters, glycerol triacetate, can be mentioned diglycerol tetraacetate, acetylated glyceride, monoglyceride, a polyhydric alcohol fatty acid esters such as diglyceride. In addition, butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, triacetin and the like are preferably used alone or in combination.

  In addition, aliphatic polyesters composed of glycol and dibasic acid such as polyethylene adipate, polybutylene adipate, polyethylene succinate, polybutylene succinate, aliphatic polyesters composed of oxycarboxylic acid such as polylactic acid, polyglycolic acid, High molecular weight plasticizers such as aliphatic polyesters composed of lactones such as polycaprolactone, polypropiolactone and polyvalerolactone, and vinyl polymers such as polyvinylpyrrolidone. These plasticizers can be used alone or in combination with a low-part plasticizer.

  Polyhydric alcohol plasticizers have good compatibility with cellulose fatty acid esters, and glycerin ester compounds such as glycerin esters and diglycerin esters that exhibit a significant thermoplastic effect, and polyalkylene glycols such as polyethylene glycol and polypropylene glycol. And compounds in which an acyl group is bonded to the hydroxyl group of polyalkylene glycol.

  Specific glycerin esters include glycerin diacetate stearate, glycerin diacetate palmitate, glycerin diacetate myristate, glycerin diacetate laurate, glycerin diacetate caprate, glycerin diacetate nonanate, glycerin diacetate octanoate, Glycerin diacetate heptanoate, glycerol diacetate hexanoate, glycerol diacetate pentanoate, glycerol diacetate oleate, glycerol acetate dicaprate, glycerol acetate dioctanoate, glycerol acetate dioctanoate, glycerol acetate diheptanoate , Glycerol acetate dicaproate, glycerol acetate divalerate, glycerol acetate dibu Glycerol dipropionate caprate, glycerol dipropionate laurate, glycerol dipropionate myristate, glycerol dipropionate palmitate, glycerol dipropionate stearate, glycerol dipropionate oleate, glycerol tributyrate, glycerol tri Examples include, but are not limited to, pentanoate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin propionate laurate, and glycerin oleate propionate. These are used alone or in combination. be able to.

  Among them, glycerol diacetate caprylate, glycerol diacetate pelargonate, glycerol diacetate caprate, glycerol diacetate laurate, glycerol diacetate myristate, glycerol diacetate palmitate, glycerol diacetate stearate, glycerol diacetate oleate preferable.

  Specific examples of diglycerin esters include diglycerin tetraacetate, diglycerin tetrapropionate, diglycerin tetrabutyrate, diglycerin tetravalerate, diglycerin tetrahexanoate, diglycerin tetraheptanoate, diglyceride. Glycerin tetracaprylate, diglycerol tetrapelargonate, diglycerol tetracaprate, diglycerol tetralaurate, diglycerol tetramyristate, diglycerol tetrapalmitate, diglycerol triacetate propionate, diglycerol triacetate butyrate, diglycerol Triacetate valerate, diglycerin triacetate hexanoate, diglycerin triacetate heptanoate, diglycerin triacetate caprylate, Glycerin triacetate pelargonate, diglycerol triacetate caprate, diglycerol triacetate laurate, diglycerol triacetate myristate, diglycerol triacetate palmitate, diglycerol triacetate stearate, diglycerol triacetate oleate, diglycerol diacetate dipropionate, diglycerol Diacetate dibutyrate, diglycerol diacetate divalerate, diglycerol diacetate dihexanoate, diglycerol diacetate diheptanoate, diglycerol diacetate dicaprylate, diglycerol diacetate dipelargonate, diglycerol di Acetate dicaprate, diglycerin diacetate dilaurate, diglycerin diacetate dimisti Diglycerin diacetate dipalmitate, diglycerin diacetate distearate, diglycerin diacetate dioleate, diglyceryl acetate tripropionate, diglyceryl acetate tributyrate, diglyceryl acetate trivalerate, diglyceryl acetate tri Hexanoate, diglycerol acetate triheptanoate, diglycerol acetate tricaprylate, diglycerol acetate tripelargonate, diglycerol acetate tricaprate, diglycerol acetate trilaurate, diglycerol acetate trimyristate, diglycerol acetate tri Palmitate, Diglycerol acetate tristearate, Diglycerol acetate trioleate, Diglycerol laurate, Jig Examples include, but are not limited to, mixed acid esters of diglycerin such as glycerin stearate, diglycerin caprylate, diglycerin myristate, and diglycerin oleate, and these can be used alone or in combination.

  Among these, diglycerin tetraacetate, diglycerin tetrapropionate, diglycerin tetrabutyrate, diglycerin tetracaprylate, and diglycerin tetralaurate are preferable.

  Specific examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol having an average molecular weight of 200 to 1000, but are not limited thereto, and these can be used alone or in combination.

  Specific examples of the compound in which an acyl group is bonded to the hydroxyl group of polyalkylene glycol include polyoxyethylene acetate, polyoxyethylene propionate, polyoxyethylene butyrate, polyoxyethylene valerate, polyoxyethylene caproate, Polyoxyethylene heptanoate, polyoxyethylene octanoate, polyoxyethylene nonanate, polyoxyethylene caprate, polyoxyethylene laurate, polyoxyethylene myristate, polyoxyethylene palmitate, polyoxyethylene stearate , Polyoxyethylene oleate, polyoxyethylene linoleate, polyoxypropylene acetate, polyoxypropylene propionate, polyoxypropylene butyrate, polyoxypropylene Valerate, polyoxypropylene caproate, polyoxypropylene heptanoate, polyoxypropylene octanoate, polyoxypropylene nonanoate, polyoxypropylene caprate, polyoxypropylene laurate, polyoxypropylene myristate, polyoxy Examples thereof include propylene palmitate, polyoxypropylene stearate, polyoxypropylene oleate, and polyoxypropylene linoleate, but are not limited thereto, and these can be used alone or in combination.

  The addition amount of the plasticizer is preferably 0 to 20% by weight, more preferably 2 to 18% by weight, and most preferably 4 to 15% by weight. When the content of the plasticizer is more than 20% by weight, the heat transferability of the cellulose acylate is improved, the plasticizer oozes out on the surface of the melt-formed film, and the glass transition temperature Tg is heat resistant. Decreases.

  Furthermore, a stabilizer for preventing thermal degradation and preventing coloring can be added to the cellulose acylate of the present invention as necessary within a range not impairing the required performance.

  As the stabilizer, a phosphite compound, a phosphite compound, a phosphate, a thiophosphate, a weak organic acid, an epoxy compound, or the like may be added alone or in admixture of two or more. As specific examples of the phosphite stabilizer, compounds described in paragraphs [0039] to [0039] of JP-A No. 2004-182979 can be more preferably used. Specific examples of the phosphite ester stabilizer include JP-A No. 51-70316, JP-A No. 10-306175, JP-A No. 57-78431, JP-A No. 54-157159, and JP-A No. 54-157159. The compounds described in Japanese Patent Application Laid-Open No. 55-13765 can be used.

  The addition amount of the stabilizer in the present invention is preferably 0.005 to 0.5% by weight, more preferably 0.01 to 0.4% by weight or more, still more preferably 0.05 to cellulose acylate. ~ 0.3% by weight. When the addition amount is less than 0.005% by weight, the effect of preventing deterioration and suppressing coloration during melt film formation is insufficient, which is not preferable. On the other hand, when the content is 0.5% by weight or more, it oozes out on the surface of the melt-formed cellulose acylate film, which is not preferable.

  It is also preferable to add a deterioration inhibitor and an antioxidant. By adding a phenol compound, a thioether compound, a phosphorus compound or the like as a deterioration inhibitor or an antioxidant, a synergistic effect appears in deterioration and oxidation prevention. Furthermore, as other stabilizers, the materials described in detail on pages 17 to 22 of the Japan Society for Invention and Technology (Public Technical Number 2001-1745, issued on March 15, 2001, Japan Society of Invention) are preferably used. Can do.

  Furthermore, the cellulose acylate in the present invention may contain an ultraviolet ray inhibitor and may contain one or more ultraviolet absorbers. From the viewpoint of preventing deterioration of the liquid crystal, the ultraviolet absorbent for liquid crystal is preferably excellent in the ability to absorb ultraviolet light having a wavelength of 380 nm or less, and has little absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. Examples include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. Particularly preferred ultraviolet absorbers are benzotriazole compounds and benzophenone compounds. Among these, a benzotriazole-based compound is preferable because unnecessary coloring with respect to cellulose ester cellulose acylate is small.

  Preferred UV inhibitors include 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol -Bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6 -Tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate and the like.

  In addition, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-tert A phosphorus processing stabilizer such as -butylphenyl) phosphite may be used in combination. The amount of these compounds added is preferably 1 ppm to 3.0%, more preferably 10 ppm to 2% in terms of mass ratio with respect to cellulose ester cellulose acylate.

These ultraviolet absorbers are available as the following commercial products.
Benzotriazoles include TINUBIN P (Ciba Specialty Chemicals), TINUBIN 234 (Ciba Specialty Chemicals), TINUBIN 320 (Ciba Specialty Chemicals), TINUBIN 326 (Ciba Specialty Chemicals), TINUBIN 327 (Ciba Specialty Chemicals) Specialty Chemicals), TINUBIN 328 (Ciba Specialty Chemicals), and Sumisobe 340 (Sumitomo Chemical). In addition, benzophenone UV absorbers include Seasorb 100 (Cipro Kasei), Seasorb 101 (Cipro Kasei), Seasorb 101S (Cipro Kasei), Seasorb 102 (Cipro Kasei), Seasorb 103 (Cipro Kasei), Adekas Type LA-51 ( Asahi Denka), Chemisorp 111 (Chemipro Kasei), UVINUL D-49 (BASF), etc. Oxalic acid anilide UV absorbers include TINUBIN 312 (Ciba Specialty Chemicals) and TINUBIN 315 (Ciba Specialty Chemicals). In addition, SeaSorb 201 (Cipro Kasei) and SeaSorb 202 (Cipro Kasei) are marketed as salicylic acid UV absorbers, and Seasorb 501 (Cipro Kasei) and UVINUL N-539 (BASF) are cyanoacrylate UV absorbers. There is.

(Saturated norbornene resin)
As the saturated norbornene-based resin used in the present invention, for example, (1) a ring-opening (co) polymer of a norbornene-based monomer is subjected to polymer modification such as maleic acid addition or cyclopentadiene addition, if necessary. Examples include hydrogenated resins, (2) resins obtained by addition polymerization of norbornene monomers, and (3) resins obtained by addition copolymerization with norbornene monomers and olefin monomers such as ethylene and α-olefin. . The polymerization method and the hydrogenation method can be performed by conventional methods.

  Examples of the norbornene-based monomer include norbornene and alkyl and / or alkylidene substituted products thereof such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, and 5-butyl- 2-Norbornene, 5-ethylidene-2-norbornene and the like, polar substituents such as halogens thereof; dicyclopentadiene, 2,3-dihydrodicyclopentadiene, etc .; dimethanooctahydronaphthalene, alkyl and / or alkylidene substitution thereof And polar group substituents such as halogen, for example, 6-methyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethyl -1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahi Lonaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-chloro-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a -Octahydronaphthalene, 6-pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5 8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, etc .; adducts of cyclopentadiene and tetrahydroindene, etc .; 3-pentamers of cyclopentadiene, such as 4,9 : 5,8-dimethano-3a, 4,4a, 5 , 8a, 9,9a-octahydro-1H-benzoindene, 4,11: 5,10: 6,9-trimethano-3a, 4,4a, 5,5a, 6,9,9a, 10,10a, 11, 11a-dodecahydro-1H-cyclopentanthracene; and the like.

  In the present invention, other cycloolefins capable of ring-opening polymerization can be used in combination as long as the object of the present invention is not impaired. Specific examples of such cycloolefins include compounds having one reactive double bond such as cyclopentene, cyclooctene, and 5,6-dihydrodicyclopentadiene.

  The saturated norbornene resin used in the present invention has a number average molecular weight of 25000 to 100,000, preferably 30000 to 80000, more preferably 35000 to 70000, as measured by a gel permeation chromatograph (GPC) method using a toluene solvent. Is in range. When the number average molecular weight is too small, the physical strength is inferior, and when the number average molecular weight is too large, the operability during molding is deteriorated.

  In the present invention, the glass transition temperature (Tg) of the saturated norbornene resin is preferably 100 ° C. or higher and 250 ° C. or lower, more preferably 115 ° C. or higher and 220 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower.

  If necessary, the thermoplastic saturated norbornene-based resin used in the present invention may be added with various additives such as an anti-aging agent such as phenol and phosphorus, an antistatic agent, and an ultraviolet absorber. In particular, since the liquid crystal is usually deteriorated by ultraviolet rays, it is preferable to add an ultraviolet absorber when other protective measures such as laminating an ultraviolet protective filter are not taken. 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 -100,000 ppm, preferably 100-10000 ppm. Moreover, when producing a sheet | seat by the solution casting method, in order to make surface roughness small, addition of a leveling agent is preferable. As the leveling agent, for example, a coating leveling agent such as a fluorine-based nonionic surfactant, a special acrylic resin leveling agent, or a silicone leveling agent can be used, and among them, those having good compatibility with a solvent are preferable. The addition amount is usually 5 to 50000 ppm, preferably 10 to 20000 ppm.

(2) Film formation Although these resins can be formed into a film by either solution film formation or melt film formation, the melt film formation method is preferable in the case of a saturated norbornene resin, and both are preferable in the case of a cellulose acylate resin. Hereinafter, solution film formation and melt film formation will be described.

(Solution casting)
Any of the following (a) chlorine-based solvents and (b) non-chlorine-based solvents can be used as the solvent for forming the cellulose acylate resin solution.

(A) Chlorine-based solvent The chlorine-based organic solvent is preferably dichloromethane or chloroform. Particularly preferred is dichloromethane. In addition, there is no particular problem in mixing an organic solvent other than the chlorinated organic solvent. In that case, it is necessary to use at least 50% by mass of dichloromethane.

  The non-chlorine organic solvent used in combination with the present invention is described below. That is, as a preferable non-chlorine organic solvent, a solvent selected from esters, ketones, ethers, alcohols, hydrocarbons and the like having 3 to 12 carbon atoms is preferable. Esters, ketones, ethers and alcohols may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO— and —COO—) can also be used as a solvent. For example, other functional groups such as alcoholic hydroxyl groups can be used. You may have group simultaneously. In the case of a solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  The alcohol used in combination with the chlorinated organic solvent may be linear, branched or cyclic, and among them, saturated aliphatic hydrocarbon is preferable. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Furthermore, the hydrocarbon may be linear, branched or cyclic. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene.

  The non-chlorine organic solvent used in combination with the chlorinated organic solvent is not particularly limited, but methyl acetate, ethyl acetate, methyl formate, ethyl formate, acetone, dioxolane, dioxane, ketones having 4 to 7 carbon atoms or It is selected from acetoacetic acid esters, alcohols having 1 to 10 carbon atoms or hydrocarbons. Preferred non-chlorine organic solvents used in combination are methyl acetate, acetone, methyl formate, ethyl formate, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl acetyl acetate, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol. , 2-butanol, and cyclohexanol, cyclohexane, and hexane.

Although the following can be mentioned as a combination of the chlorinated organic solvent which is a preferable main solvent of this invention, It is not limited to these (the number in the following parenthesis shows a mass part).・ Dichloromethane / methanol / ethanol / butanol (80/10/5/5)
・ Dichloromethane / acetone / methanol / propanol (80/10/5/5)
・ Dichloromethane / methanol / butanol / cyclohexane (80/10/5/5)
・ Dichloromethane / methyl ethyl ketone / methanol / butanol (80/10/5/5)
・ Dichloromethane / acetone / methyl ethyl ketone / ethanol / isopropanol (72/9/9/4/6)
・ Dichloromethane / cyclopentanone / methanol / isopropanol (80/10/5/5)
・ Dichloromethane / methyl acetate / butanol (80/10/10)
・ Dichloromethane / cyclohexanone / methanol / hexane (70/20/5/5)
・ Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5)
・ Dichloromethane / 1, 3 dioxolane / methanol / ethanol (70/20/5/5)
・ Dichloromethane / dioxane / acetone / methanol / ethanol (60/20/10/5/5)
・ Dichloromethane / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5)
・ Dichloromethane / methyl ethyl ketone / acetone / methanol / ethanol (70/10/10/5/5)
・ Dichloromethane / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5)
・ Dichloromethane / methyl acetoacetate / methanol / ethanol (65/20/10/5)
・ Dichloromethane / cyclopentanone / ethanol / butanol (65/20/10/5)
(B) Non-chlorine solvent The preferred non-chlorine organic solvent is preferably a solvent selected from esters, ketones and ethers having 3 to 12 carbon atoms. Esters, ketones and ethers may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO—, and —COO—) can also be used as a main solvent, such as an alcoholic hydroxyl group. It may have a functional group of In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  Furthermore, a preferred solvent for the cellulose acylate of the present invention is a mixed solvent of three or more different types, and the first solvent is at least selected from methyl acetate, ethyl acetate, methyl formate, ethyl formate, acetone, dioxolane, and dioxane. One or a mixture thereof, the second solvent is selected from ketones having 4 to 7 carbon atoms or acetoacetate, and the third solvent is an alcohol or hydrocarbon having 1 to 10 carbon atoms. More preferably, it is an alcohol having 1 to 8 carbon atoms. Note that when the first solvent is a mixed liquid of two or more kinds of solvents, the second solvent may be omitted. The first solvent is more preferably methyl acetate, acetone, methyl formate, ethyl formate, or a mixture thereof, and the second solvent is preferably methyl ethyl ketone, cyclopentanone, cyclohexanone, or methyl acetyl acetate. It may be.

  The alcohol as the third solvent is preferably linear, branched or cyclic, and is preferably a saturated aliphatic hydrocarbon. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Furthermore, the hydrocarbon may be linear, branched or cyclic. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene. These alcohols and hydrocarbons as the third solvent may be used alone or in combination of two or more, and are not particularly limited. As the third solvent, preferred specific compounds include alcohol, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and cyclohexanol, cyclohexane, hexane, Are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol.

  The above three types of mixed solvents preferably contain a first solvent in a proportion of 20 to 95% by mass, a second solvent in a proportion of 2 to 60% by mass, and a third solvent in a proportion of 2 to 30% by mass, Furthermore, it is preferable that a 1st solvent is 30-90 mass%, a 2nd solvent is 3-50 mass%, and also 3-25 mass% of 3rd alcohol is contained. In particular, it is preferable that the first solvent is 30 to 90% by mass, the second solvent is 3 to 30% by mass, and the third solvent is alcohol and 3 to 15% by mass. In addition, when the first solvent is a mixed solution and the second solvent is not used, the first solvent is preferably contained in a ratio of 20 to 90% by mass and the third solvent in a ratio of 5 to 30% by mass, Furthermore, it is preferable that a 1st solvent is 30-86 mass%, and also a 3rd solvent is contained 7-25 mass%. The non-chlorine organic solvent used in the present invention is described in more detail in pages 12 to 16 in the Japan Society for Invention and Technology (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society for Invention). It is described in detail.

Preferred combinations of non-chlorine organic solvents of the present invention can be listed below, but are not limited thereto (the numbers in parentheses indicate parts by mass).
・ Methyl acetate / acetone / methanol / ethanol / butanol (75/10/5/5/5)
・ Methyl acetate / acetone / methanol / ethanol / propanol (75/10/5/5/5)
・ Methyl acetate / acetone / methanol / butanol / cyclohexane (75/10/5/5/5)
・ Methyl acetate / acetone / ethanol / butanol (81/8/7/4)
・ Methyl acetate / acetone / ethanol / butanol (82/10/4/4)
・ Methyl acetate / acetone / ethanol / butanol (80/10/4/6)
・ Methyl acetate / methyl ethyl ketone / methanol / butanol (80/10/5/5)
・ Methyl acetate / acetone / methyl ethyl ketone / ethanol / isopropanol (75/8/8/4/5)
・ Methyl acetate / cyclopentanone / methanol / isopropanol (80/10/5/5)
・ Methyl acetate / acetone / butanol (85/10/5)
・ Methyl acetate / cyclopentanone / acetone / methanol / butanol (60/15/15/5/5)
・ Methyl acetate / cyclohexanone / methanol / hexane (70/20/5/5)
・ Methyl acetate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5)
・ Methyl acetate / 1, 3 dioxolane / methanol / ethanol (70/20/5/5)
・ Methyl acetate / dioxane / acetone / methanol / ethanol (60/20/10/5/5)
・ Methyl acetate / acetone / cyclopentanone / ethanol / isobutanol / cyclohexane (65/10/10/5/5/5)
・ Methyl formate / methyl ethyl ketone / acetone / methanol / ethanol (50/20/20/5/5)
・ Methyl formate / acetone / ethyl acetate / ethanol / butanol / hexane (65/10/10/5/5/5)
Acetone / methyl acetoacetate / methanol / ethanol (65/20/10/5)
Acetone / cyclopentanone / ethanol / butanol (65/20/10/5)
Acetone / 1,3 dioxolane / ethanol / butanol (65/20/10/5)
1,3 dioxolane / cyclohexanone / methyl ethyl ketone / methanol / butanol (55/20/10/5/5/5)
Further, as described below, it is also preferable to add a part of the solvent after dissolution and dissolve in multiple stages (the numbers in parentheses indicate parts by mass).
-Prepare a cellulose acylate solution with methyl acetate / acetone / ethanol / butanol (81/8/7/4), add 2 parts by weight of butanol after filtration and concentration-Methyl acetate / acetone / ethanol / butanol (81 / 10/4/2) to prepare a cellulose acylate solution, and after filtration and concentration, add 4 parts by weight of butanol additionally. Prepare a cellulose acylate solution with methyl acetate / acetone / ethanol (84/10/6). Further, 5 parts by weight of butanol is added after filtration / concentration. In the present invention, it is preferable that cellulose acylate is dissolved in the solvent in an amount of 10 to 40% by mass, more preferably in any case of chlorinated or non-chlorinated solvents. Is 13 to 35% by mass, and particularly 15 to 30% by mass. Prior to dissolution, it is preferable to swell at 0 ° C. to 50 ° C. for 0.1 to 100 hours. Various additives may be added before the swelling step, during or after the swelling step, and further during or after cooling and dissolution.

  In the present invention, a cooling / heating method may be used to dissolve the cellulose acylate. The cooling / heating method is described in JP-A-11-323017, JP-A-10-67860, JP-A-10-95854, JP-A-10-324774, and JP-A-11-302388. Can be used. That is, a solvent and cellulose acylate mixed and swollen are dissolved using a screw-type kneader provided with a cooling jacket.

  Further, the dope of the present invention is preferably subjected to concentration and filtration, which are described in detail on page 25 in the Japan Society for Invention and Technology (public technical number 2001-1745, published on March 15, 2001, Japan Society for Invention). You can use what is described.

(Melting film formation)
(A) Cellulose acylate film [dry]
The resin may be used in the form of powder, but it is more preferable to use a pelletized resin in order to reduce the thickness fluctuation of the film formation. This resin has a moisture content of 1% or less, more preferably 0.5% or less, and is then charged into a hopper of a melt extruder. At this time, the hopper is Tg-50 ° C. or higher and Tg + 30 ° C. or lower, more preferably Tg−40 ° C. or higher and Tg + 10 ° C. or lower, further preferably Tg−30 ° C. or higher and Tg or lower. Thereby, the re-adsorption of the water | moisture content in a hopper can be suppressed, and the said drying efficiency can be expressed more easily.
[Kneading extrusion]
It is kneaded and melted at 120 to 250 ° C., more preferably 140 to 220 ° C., and even more preferably 150 to 200 ° C. At this time, the melting temperature may be a constant temperature, or may be divided into several parts and controlled. The kneading time is preferably 2 minutes or more and 60 minutes or less, more preferably 3 minutes or more and 40 minutes or less, and further preferably 4 minutes or more and 30 minutes or less. Furthermore, it is also preferable to carry out the inside of the melt extruder in an inert (nitrogen or the like) air flow or while evacuating using a vented extruder.
[cast]
The melted resin is passed through a gear pump and the pulsation of the extruder is removed, followed by filtration with a metal mesh filter or the like, and extruded from a T-shaped die attached to the cooling drum onto a cooling drum. Extrusion may be performed in a single layer, or multiple layers may be extruded using a multi-manifold die or a feed block die. At this time, the thickness unevenness in the width direction can be adjusted by adjusting the distance between the lips of the die.

  Thereafter, it is extruded onto a casting drum. At this time, it is preferable to use a method such as an electrostatic application method, an air knife method, an air chamber method, a vacuum nozzle method, or a touch roll method to increase the adhesion between the casting drum and the melt-extruded sheet. Such an adhesion improving method may be performed on the entire surface of the melt-extruded sheet or a part thereof.

  The casting drum is preferably 60 ° C. or higher and 160 ° C. or lower, more preferably 70 ° C. or higher and 150 ° C. or lower, and further preferably 80 ° C. or higher and 150 ° C. or lower. Then, it peels off from a casting drum, winds up after passing through a nip roll. The winding speed is preferably from 10 m / min to 100 m / min, more preferably from 15 m / min to 80 m / min, still more preferably from 20 m / min to 70 m / min.

  The film forming width is preferably 1 m or more and 5 m or less, more preferably 1.2 m or more and 4 m or less, and still more preferably 1.3 m or more and 3 m or less. The thickness of the unstretched film thus obtained is preferably from 30 μm to 400 μm, more preferably from 40 μm to 300 μm, still more preferably from 50 μm to 200 μm.

  The sheet thus obtained is preferably trimmed at both ends and wound up. The trimmed part is recycled as a raw material for the same type of film or as a raw material for a film of a different type after being pulverized or after being subjected to a granulation process or a depolymerization / repolymerization process as necessary. May be used. Moreover, it is also preferable from a viewpoint of scratch prevention to attach a lami film to at least one surface before winding.

(B) Saturated norbornene film Saturated norbornene resin pellets are put into a melt extruder, dehydrated at 100 ° C to 200 ° C for 1 minute to 10 hours, and then kneaded and extruded. For kneading, a single-screw or twin-screw extruder can be used.

  The melting temperature is 240 to 320 ° C, more preferably 250 to 310 ° C, still more preferably 260 to 300 ° C, and the temperature of the casting drum is 80 to 170 ° C, more preferably 90 ° C to 160 ° C, and still more preferably 100 ° C. The film can be formed in the same manner as the cellulose acylate film except that the temperature is 150 ° C. or lower.

  The thickness unevenness of the thermoplastic film formed by the above method is preferably 0% or more and 2% or less in both the longitudinal direction and the width direction, more preferably 0% or more and 1.5% or less, and further preferably 0% or more and 1% or less. These are stretched by the above method to obtain the thermoplastic film of the present invention.

(3) Processing of thermoplastic film The stretched thermoplastic film stretched biaxially by the method described above may be used alone, or may be used in combination with a polarizing plate, and a liquid crystal layer is formed thereon. Alternatively, a layer having a controlled refractive index (low reflection layer) or a hard coat layer may be provided. These can be achieved by the following steps.

(surface treatment)
By performing a surface treatment on the thermoplastic film, adhesion with each functional layer (for example, the undercoat layer and the back layer) can be improved. For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs under a low pressure gas of 10-3 to 20 Torr, and plasma treatment under atmospheric pressure is also preferred. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes 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 in pages 30 to 32 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical Number 2001-1745, published 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.

  Among these, particularly preferred is an alkali saponification treatment in the case of a cellulose acylate film, and glow discharge treatment, corona treatment, and flame treatment in the case of a saturated norbornene film.

  The alkali saponification treatment may be immersed in a saponification solution (immersion method) or a saponification solution may be applied (application method). In the case of the dipping method, it can be achieved by passing an aqueous solution of pH 10 to 14 such as NaOH or KOH through a bath heated to 20 ° C. to 80 ° C. for 0.1 to 10 minutes, and then neutralizing, washing with water and drying. .

  In the case of the coating method, a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, and an E-type coating method can be used. The solvent of the alkali saponification coating solution has good wettability because it is applied to the transparent support of the saponification solution, and the surface state remains good without forming irregularities on the surface of the transparent support by the saponification solution solvent. It is preferred to select a solvent to keep. Specifically, an alcohol solvent is preferable, and isopropyl alcohol is particularly preferable. An aqueous solution of a surfactant can also be used as a solvent. The alkali of the alkali saponification coating solution is preferably an alkali that dissolves in the above solvent, and more preferably KOH or NaOH. The pH of the saponification coating solution is preferably 10 or more, more preferably 12 or more. The reaction conditions during alkali saponification are preferably 1 second to 5 minutes at room temperature, more preferably 5 seconds to 5 minutes, and particularly preferably 20 seconds to 3 minutes. After the alkali saponification reaction, it is preferable to wash the surface on which the saponification solution is applied with water or with an acid and then with water. Further, the coating-type saponification treatment and the alignment film uncoating described later can be performed continuously, and the number of steps can be reduced. Specific examples of these saponification methods are described in JP-A-2002-82226 and WO02 / 46809.

  It is also preferable to provide an undercoat layer for adhesion to the functional layer. This layer may be coated after the above 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 in the Invention Association's public technical report (public technical number 2001-1745, published on March 15, 2001, Invention Association) is applied to the thermoplastic 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 (creation of polarizing plate)
(A-1) Material used Currently, a commercially available polarizing layer is obtained by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing iodine or dichroic dye to penetrate into the binder. It is common to make it. As the polarizing film, a coating type polarizing film represented by Optiva Inc. 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. 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. 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 (weight ratio before swelling and after swelling). Thereafter, the film is stretched at a bath temperature of 15 to 50 ° C., especially 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 moisture content is preferably 5% or more and 100% or less, more preferably 10% or more and 100% or less.

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

  After the stretching is completed, the film is dried at 50 ° C. or higher and 100 ° C. or lower, more preferably 60 ° C. or higher and 90 ° C. or lower, and 0.5 minutes or longer and 10 minutes or shorter. More preferably, it is 1 minute or more and 5 minutes or less.

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

(A-3) Bonding The cellulose acylate film after saponification and a polarizing layer prepared by stretching are bonded to prepare a polarizing plate. The laminating direction is preferably such that the casting axis direction of the cellulose acylate film and the stretching axis direction of the polarizing plate are 45 degrees.

  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% with respect to 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 degrees 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 (creation of optical compensation sheet)
The optically anisotropic layer is for compensating 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 cellulose acylate film, and further provides an optically anisotropic layer. It is formed by doing.

(B-1) Alignment film An alignment film is provided on the surface-treated cellulose acylate 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 a 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 for 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 JP-A No. 2002-62426 are described. And the like described in [0022].

  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 [024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a 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.

  The alignment film can be basically formed by applying the polymer on the transparent support containing the alignment film forming material and the crosslinking agent, followed by drying by heating (crosslinking) and rubbing treatment. As described above, the crosslinking reaction may be carried out 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 solution 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 orientation 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 wrap angle of the film 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, it is preferably 40 to 50 °, particularly preferably 45 °.

  The film 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), Physicslett, 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 a 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 paragraph numbers [0151] to [0168] in JP-A 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 also be adjusted by selecting liquid crystalline 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 liquid crystal molecules have compatibility with the liquid crystal molecules and can change the tilt angle of the liquid crystal molecules or do 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 above-described 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 in the range of 0.1 to 8% by mass with respect to the liquid crystal molecule so as not to inhibit 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. No. 2,367,661 and US Pat. No. 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. An acyloin compound (described in US Pat. No. 2,722,512), a polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of a triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Description), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970) are included.

  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 20 mJ / cm ² to 50 J / cm ^2, more preferably in the range of 20 to 5000 mJ / cm ^2, and still 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 inclination angle of the polarizing layer and the optical compensation layer may be 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. preferable. 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)
It 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)
This is a bend alignment mode liquid crystal cell in which rod-like liquid crystal molecules are aligned in a substantially opposite direction (symmetrically) between the upper and lower portions of the liquid crystal cell. A liquid crystal display device using a bend alignment mode liquid crystal cell is 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. Therefore, 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 crystal molecules rise in the center of the cell and the rod-like liquid crystal molecules lie in the vicinity of the cell substrate. .
(VA mode liquid crystal display device)
The feature is that the rod-like liquid crystalline molecules are oriented substantially vertically when no voltage is applied. In the VA mode liquid crystal cell, (1) the rod-like liquid crystalline molecules are oriented substantially vertically when no voltage is applied. In addition to a narrowly defined VA mode liquid crystal cell (described in JP-A-2-176625) that is aligned substantially horizontally when a voltage is applied, (2) the VA mode is multi-domained to expand the viewing angle ( Liquid crystal cell (in MVA mode) (SID97, Digest of tech. Papers 28 (1997) 845), (3) Rod-like liquid crystal molecules are substantially vertically aligned when no voltage is applied, and twisted A liquid crystal cell in a domain alignment mode (n-ASM mode) (described in the proceedings 58-59 (1998) of the Japanese Liquid Crystal Society) and (4) a SURVAVAL mode liquid crystal cell (LCD interface) Announced at National 98).
(Other liquid crystal display devices)
The ECB mode and STN mode liquid crystal display devices can be optically compensated in the same way as described above.

(C) Application of an antireflection layer (antireflection film)
The antireflection film generally comprises 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 also mentioned.

  The cellulose acylate 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

  Refractive index of high refractive index layer> refractive index of medium refractive index layer> refractive index of transparent support> refractive index of low refractive index layer Alternatively, a hard coat layer is provided between the transparent support and the intermediate refractive index layer. Also good. 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. In addition, each layer may be provided with other functions. For example, an antifouling low refractive index layer or an antistatic high refractive index layer (for example, JP-A-10-206603, JP 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 layer having a high refractive index of the antireflection film is a curable film containing at least inorganic compound ultrafine particles having a high refractive index having 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, a silane coupling agent, etc .: JP-A Nos. 1-295503, 11-153703, and 2000- 9908, 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 dispersant Combined use (for example, Unexamined-Japanese-Patent No. 11-153703, patent number US6210858B1, Unexamined-Japanese-Patent No. 2002-27776069 etc.) etc. are mentioned.

  Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films. Furthermore, 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 2000-47004, JP-A 2001-315242, JP-A 2001-31871, JP-A 2001-296401, and the like.

  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 silicone 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 paragraphs of Japanese Patent Application Laid-Open No. 2001-40284. Examples thereof include compounds described in Nos. [0027] to [0028] and JP-A No. 2000-284102.

  The silicone 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 silicone (eg, Silaplane (manufactured by Chisso Corporation), silanol group-containing polysiloxane (Japanese Patent 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 performed simultaneously with or after the application of the coating composition for forming the outermost layer containing a polymerization initiator, a sensitizer and the like. 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 (JP 58-142958, JP 58-147483, JP 58-147484, JP 9-157582). Compounds described in JP-A-11-106704, etc.), silyl compounds containing a poly "perfluoroalkyl ether" group which is a fluorine-containing long chain group (JP-A No. 2000-117902, JP-A No. 2001-48590) And the compounds described in JP-A-2002-53804).

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

  When the low refractive index layer is positioned 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.

(Her 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 hydrous 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 No. 2002-144913, JP-A No. 2000-9908, WO 0/46617, and the like.

  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 JISK5400, the smaller the amount of wear 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 Application Laid-Open No. 11-38208 specifying a forward scattering coefficient, Japanese Patent Application Laid-Open No. 2000-199809 having a relative refractive index of a transparent resin and fine particles in a specific range, and Japanese Patent Application 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 relatively large particle (particle size 0.05 to 2 μm) is added to a hard coat layer in a small amount (0.1 to 50% by mass) to form a surface uneven film, and these shapes are maintained on it. A method of providing a low refractive index layer (for example, JP-A No. 2000-281410, JP-A No. 2000-95893, JP-A No. 2001-100004, JP-A No. 2001-281407, etc.), uppermost layer (antifouling property) A method of physically transferring the uneven shape onto the surface after coating the layer (for example, as an embossing method, JP-A-63-278839, JP-A-11-183710, JP-A-2000-275401) etc Mounting) and the like.

  Next, various measurement methods in the present invention will be described.

(Boeing distortion calculation method)
A straight line is drawn in the width direction on the surface of the film before stretching in the transverse direction, and bowing is performed according to the following formula from the situation of the arcuate line obtained by deforming the film finally obtained as shown in FIG. Distortion was calculated.
B = b / W × 100 (%)
Where B = Boeing distortion (%)
W = film width (mm)
b = Maximum concave amount of the Boeing line (mm)
(Re, Rth, width direction, longitudinal direction Re, Rth fluctuation measurement method)
In the MD direction (longitudinal direction) sampling, 100 points and 1 cm square were cut at 0.5 m intervals in the longitudinal direction. The sampling in the TD direction (width direction) was cut out at equal intervals of 50 points in the size of 1 cm square over the entire width of film formation. Re, Rth, and orientation angle measurements were performed using an automatic birefringence meter (KOBRA-21ADH / PR: manufactured by Oji Scientific Instruments) after conditioning the sample film at 25 ° C. and 60% rh for 3 hours or more. At a temperature of 60% rh, the retardation value at a wavelength of 550 nm and the tilt of the slow axis were measured from the direction perpendicular to the sample film surface and ± 40 ° from the normal to the film surface. The in-plane retardation (Re) from the vertical direction and the tilt of the slow axis with respect to the flow direction were calculated as the orientation angle, and Rth was calculated from the measured values in the vertical direction and ± 40 ° direction. The total average of the sampling points was defined as Re, Rth, and orientation angle.

  Re, Rth, and orientation angle fluctuations were obtained by dividing the difference between each maximum value and minimum value at 100 points in the MD direction and 50 points in the TD direction by each average value, and expressing the percentage as Re and Rth fluctuations. Regarding the orientation angle, the difference between the maximum value and the minimum value of each point was directly changed.

(Degree of substitution of cellulose acylate)
The degree of acyl substitution of cellulose acylate is described in Carbohydr. Res. 273 (1995) 83-91 (Tezuka et al.).

1. Thermoplastic resin (1) Cellulose acylate Cellulose acylates with different types of acyl groups and different degrees of substitution described in Table 1 (FIG. 4) were prepared. This was carried out by adding sulfuric acid (7.8 parts by weight with respect to 100 parts by weight of cellulose) as a catalyst, adding carboxylic acid as a raw material for the acyl substituent, and carrying out an acylation reaction at 40 ° C. At this time, the kind and substitution degree of the acyl group were adjusted by adjusting the kind and amount of the carboxylic acid. Moreover, it age | cure | ripened at 40 degreeC after acylation. The degree of polymerization of the cellulose acylate thus obtained was determined by the following method and listed in Tables 1 and 2.

(Measurement of polymerization degree) About 0.2 g of completely dried cellulose acylate was precisely weighed and dissolved in 100 ml of a mixed solvent of methylene chloride: ethanol = 9: 1 (mass ratio). This was measured with an Ostwald viscometer for the number of seconds dropped at 25 ° C., and the degree of polymerization was determined by the following equation.
ηrel = T / T0
[Η] = (1nηrel) / C
DP = [η] / Km
However, T is the number of seconds for dropping the measurement sample, T0 is the number of seconds for dropping the solvent alone, C is the concentration (g / l), and Km is 6 × 10 ⁻⁴ .

  These Tg were measured by the following methods and listed in Tables 1 and 2. In addition, what added the plasticizer showed the value measured after plasticizer addition.

  (Tg measurement) 20 mg of a sample was placed in a DSC measurement pan. This is heated from 30 ° C. to 250 ° C. at 10 ° C./min in a nitrogen stream (1st-run), and then cooled to 30 ° C. at −10 ° C./min. Thereafter, the temperature was raised again from 30 ° C. to 250 ° C. (2nd-run). The temperature at which the baseline begins to deviate from the low temperature side in 2nd-run is shown in Tables 1 and 2 as the glass transition temperature (Tg). Moreover, 0.05 mass% of silicon dioxide part particles (Aerosil R972V) were added to all levels.

(2) Saturated norbornene resin 6-methyl-1,4,5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene and 15% cyclohexane of triethylaluminum as a polymerization catalyst 10 parts of a solution, 5 parts of triethylamine, and 10 parts of a 20% cyclohexane solution of titanium tetrachloride are added and subjected to ring-opening polymerization in cyclohexane. The resulting ring-opening polymer is hydrogenated with a nickel catalyst to obtain a polymer solution. Obtained. This polymer solution was coagulated in isopropyl alcohol and dried to obtain a powdery resin. The number average molecular weight of this resin was 40000, the hydrogenation rate was 99.8% or more, and Tg was 139 ° C.

(3) Polycarbonate resin (PC resin)
According to Example 1 of JP2003-29040, a PC resin modified with 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene was obtained. The Tg of this PC resin was 215 ° C.

2. Film Formation (1) Melt Film Formation The cellulose acylate and saturated norbornene resin were formed into cylindrical pellets having a diameter of 3 mm and a length of 5 mm. At this time, the plasticizer was selected from the following (described in Table 1) and kneaded into pellets. This was dried with a vacuum dryer at 110 ° C., the water content was adjusted to 0.1% or less, and charged into a hopper adjusted to Tg−10 ° C.

  In Table 1, TPP: triphenyl phosphate, BDP: biphenyl diphenyl phosphate, DOA: bis (2-ethylhexyl) adipate, PTP: 1,4-phenylene-tetraphenyl phosphate are shown.

  The melt temperature is adjusted so that the melt viscosity becomes 1000 Pa · s, and after melting at this temperature for 5 minutes using a single-screw kneader, the T-die set to 10 ° C. higher than the melt temperature is changed to Tg-5 ° C. The film was cast and solidified on a set casting drum. At this time, each level electrostatic application method (a 10 kV wire was placed 10 cm from the point where the melt was attached to the casting drum) was used. The solidified melt was peeled off and wound up. In addition, after trimming both ends (each 3% of the total width) immediately before winding, a thickness increasing process (knurling) having a width of 10 mm and a height of 50 μm was applied to both ends. In each level, the width was 1.5 m, and 3000 m was wound at 30 m / min.

(2) Solution casting (cellulose acylate)
(A) Preparation After drying the cellulose acylate resin so that the water content is 0.1 wt% or less, the plasticizer described in Table 1 is added, and the cellulose acylate is dissolved in a solvent selected from the following. It melt | dissolved so that it might become 25 weight%.
Non-chlorine system: methyl acetate / acetone / methanol / ethanol / butanol (80/5/7/5/3, parts by mass)
Chlorine: dichloromethane / methanol / ethanol / butanol (85/6/5/4, parts by mass)
The plasticizer was selected from the above TPP, BDP, DOA, and PTP and listed in Table 2 (FIG. 5). In addition, the following additives were added to each level.
Optical anisotropy control agent: plate-like compound (3 wt%) described in (Chemical Formula 1) described in JP-A-2003-66230
UV agent a: 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine (0.5 wt%)
UV agent b: 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole (0.2 wt%)
UV agent c: 2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole (0.1 wt%)
Fine particles: silicon dioxide (particle size 20 nm), Mohs hardness of about 7 (0.25 wt%)
・ Citric acid ethyl ester (1: 1 mixture of monoester and diester, 0.2 wt%)
However, all the above addition amounts (wt%) are ratios relative to cellulose acylate.

(B) Swelling / dissolution The cellulose acylate, solvent and additives were charged into the solvent while stirring. When the addition was completed, stirring was stopped and the slurry was swelled at 25 ° C. for 3 hours to prepare a slurry. This was stirred again to completely dissolve the cellulose acylate.

(C) Filtration / concentration Thereafter, the solution is filtered with a filter paper having absolute filtration accuracy of 0.01 mm (manufactured by Toyo Filter Paper Co., Ltd., # 63), and further filtered with a filter paper having absolute filtration accuracy of 2.5 μm (FH025, manufactured by Pole). Filtered.

(D) Film formation The above-mentioned dope was heated to 35 ° C. and cast by one of the following methods (described in Table 2).

(D-1) Band method It was cast on a mirror surface stainless steel support having a band length of 60 m set at 15 ° C. through a Giesser. The Gieser used was similar to that described in JP-A-11-314233. The casting speed was 60 m / min and the casting width was 250 cm.

  After the residual solvent was peeled off at 100 wt%, the film was dried at 130 ° C. and then wound up when the residual solvent shown in Table 1 was obtained to obtain a cellulose acylate film. The obtained film was trimmed at both ends by 3 cm, and then a knurling having a height of 100 μm was imparted to a portion 2 to 10 mm from both ends, and wound into a 3000 m roll.

(D-2) Drum method It was cast through a Giesser into a 3 m diameter mirror surface stainless steel drum set at -15 ° C. The Gieser used was similar to that described in JP-A-11-314233. The casting speed was 100 m / min and the casting width was 250 cm.

  After the residual solvent was peeled off at 200 wt%, the film was dried at 130 ° C., and then taken up when it became the residual solvent in Table 1, and a cellulose acylate film was obtained. The obtained film was trimmed at both ends by 3 cm, and then a knurling having a height of 100 μm was imparted to a portion 2 to 10 mm from both ends, and wound into a 3000 m roll.

(PC)
According to Example 1 of Japanese Patent Laid-Open No. 2003-29040, after being dissolved in dichloromethane at 19 wt%, it was extruded onto a band from a T-die and peeled off when the residual solvent was 35 wt%, and then used for stretching. .

3. Stretch (simultaneous biaxial stretching)
The thermoplastic film obtained by the above melt film formation and solution film formation was stretched under the conditions described in Table 2 while maintaining the above-mentioned residual volatile content. In addition, the stretching temperature for each level of material (the one containing the plasticizer was measured in this state) is shown in Table 1 with the temperature of + and- It is shown as “vs. Tg”. The evaluation results of the stretched film thus obtained are shown in Tables 1 and 2. The stretched film thus obtained was measured for Re, Rth (average value), orientation angle, and variation rate thereof by the methods described above, and are shown in Tables 1 and 2. In addition, adhesion unevenness was also measured by the above method and displayed in Tables 1 and 2.

(Sequential biaxial stretching)
The cellulose acylate film obtained by the above melt film formation and solution film formation was preheated at the temperatures described in Tables 1 and 2, and then longitudinally stretched at the temperatures described in Tables 1 and 2. It should be noted that the stretching temperature for each level is shown as “vs. Tg” in Table 1 at a temperature of + and −, respectively, which is higher or lower than the Tg of each level of resin. Thereafter, transverse stretching was performed with a tenter under the conditions described in Tables 1 and 2. The thermoplastic film of the present invention stretched in this manner has a maximum value and a minimum value of Re, Rth (total width is divided equally into 10 and measured 10 times at a distance of 1 m in the longitudinal direction (total of 100 points). The difference between the values of Re and Rth was 5% or less. Further, the orientation angle and bowing distortion were measured and shown in Tables 1 and 2.

4). Preparation of Polarizing Plate (1) Surface Treatment (1-1) Cellulose Acylate Film The stretched cellulose acylate film was saponified by any of the following methods and listed in Tables 1 and 2.

(A) Coating Saponification 20 parts by weight of water was added to 80 parts by weight of iso-propanol, and KOH was dissolved to 1.5 N, and the temperature was adjusted to 60 ° C. and used as a saponification solution. This was coated on a cellulose acylate film at 60 ° C. at 10 g / m ² and saponified for 1 minute. Thereafter, hot water at 50 ° C. was sprayed at 10 l / m ² · min for 1 minute for cleaning.

(B) Immersion saponification A 1.5 N aqueous solution of NaOH was used as a saponification solution. The temperature was adjusted to 60 ° C., and the cellulose acylate film was immersed for 2 minutes. Thereafter, it was immersed in a 0.1N aqueous sulfuric acid solution for 30 seconds and then passed through a water-washing bath.

(1-2) Saturated norbornene film, PC film The surface of the film was subjected to corona treatment so that the contact angle with water on the surface was 60 degrees.

(2) Creation of Polarizing Layer A polarizing layer having a thickness of 20 μm was prepared by any of the following methods (described in Tables 1 and 2). In the present invention, a film that has been stretched and imparted polarizing ability is called a polarizing layer, and a film sandwiched between at least two protective films or retardation films is called a polarizing plate.

(A) Diagonal Stretching Method According to Example 1 of Japanese Patent Application Laid-Open No. 2002-86554, stretching was performed using a tenter so that the stretching axis was 45 degrees obliquely.

(B) Parallel Stretching Method According to Example 1 of Japanese Patent Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls and stretched in the longitudinal direction.

(3) Bonding The polarizing layer thus obtained was sandwiched between the saponified stretched thermoplastic film (retardation plate) and the saponified polarizing plate protective film (trade name: Fujitac). At this time, when the retardation plate is cellulose acylate, the retardation plate and the polarizing layer are bonded using a PVA (PVA-117H manufactured by Kuraray Co., Ltd.) 3% aqueous solution as an adhesive, and the retardation plate is otherwise. Were bonded using an epoxy adhesive. The above PVA aqueous solution was bonded as an adhesive between Fujitac and the polarizing layer. The laminating direction was such that the longitudinal direction of the polarization axis and the retardation plate was 45 degrees. The polarizing plate thus obtained has a retardation plate on the liquid crystal side and a Fujitack on the outside (viewing side), and the 20-inch VA liquid crystal described in FIGS. 2 to 9 of JP-A-2000-154261. Tables 1 and 2 show the frequency of occurrence of display unevenness per unit area after being mounted on a display device liquid crystal display device and visually evaluated. In the case of carrying out the present invention, uniform and good performance was obtained.

5. Preparation of Optical Compensation Film Instead of the cellulose acetate film coated with the liquid crystal layer of Example 1 of JP-A-11-316378, the stretched thermoplastic film of the present invention was used. A good optical compensation film was prepared.

  In place of the cellulose acetate film coated with the liquid crystal layer of Example 1 of JP-A-7-333433, the stretched thermoplastic film of the present invention was changed to produce an optical compensation filter film (described as optical compensation film B). A good optical compensation film could be produced.

  On the other hand, those outside the scope of the present invention have deteriorated optical characteristics. In particular, one according to Example 1 of JP 2002-31240 A (Comparative Example 1-4 in Table 1), one according to sample No. S-11 in Examples of JP 2003-315551 (Table) 2 of Comparative Example 2-4) and that according to Example 1 of Japanese Patent Application Laid-Open No. 2001-42130 (Comparative Example 2-5 of Table 2) were particularly markedly reduced.

6). Production of Low Reflective Film A stretched thermoplastic film of the present invention was produced by using the stretched thermoplastic film of the present invention according to Example 47 of the Japan Institute of Invention and Technology (Publication No. 2001-1745). Good optical performance was obtained.

7). Preparation of liquid crystal display element The polarizing plate of the present invention is applied to the liquid crystal display device described in Example 1 of JP-A-10-48420 and the discotic liquid crystal molecule described in Example 1 of JP-A-9-26572. Including an optically anisotropic layer, an alignment film coated with polyvinyl alcohol, a 20-inch VA liquid crystal display device described in FIGS. 2 to 9 of JP-A-2000-154261, and FIGS. 10 to 10 of JP-A-2000-154261. 15 in the 20-inch OCB type liquid crystal display device. Furthermore, when the low reflection film of the present invention was applied to the outermost layer of these liquid crystal display devices and evaluated, a uniform and good liquid crystal display element free from display unevenness due to adhesion marks as shown in Tables 1 and 2 was obtained. Got.

8). Results Table 1 shows the results of stretching with a melt film-forming film. In Table 1, Examples 1-1 to 6 are the results of sequential biaxial stretching with a cellulose acylate film, and the temperature immediately after stretching in transverse stretching was made lower than Tg, so Re, Rth, and orientation It was possible to produce a film with corners in appropriate ranges. On the other hand, in Comparative Example 1-1, since the temperature immediately after stretching was higher than Tg, the fluctuation rates of Re, Rth, and orientation angle were increased, and the average orientation angle was in an inappropriate range.

  Similarly, in Examples 1-7 to 19 in which simultaneous biaxial stretching was performed, since the temperature immediately after stretching was set lower than Tg, films with appropriate ranges of Re, Rth, and orientation angles were obtained. However, in Comparative Example 1-3, since the temperature immediately after stretching was higher than Tg, the average value and variation of the orientation angle became inappropriate. Also in Comparative Example 1-2, in which the preheating temperature was lower than the temperature immediately after stretching, a film with an inappropriate orientation angle average value and fluctuation was obtained.

  Examples 1 to 20 to 35 are the results of sequential stretching, and the tests are performed by changing the degree of substitution, the degree of polymerization, the amount of plasticizer added, and the like. Also in this case, since the temperature immediately after stretching was lower than Tg, good results were obtained.

  Example 1-36 and Comparative Example 1-4 are the results of stretching a saturated norbornene-based film. In Comparative Example 1-4, in which the temperature immediately after stretching is lower than the preheating temperature, the average value and variation of the orientation angle are not satisfactory. Appropriate film.

  Table 2 shows the results of stretching with a solution casting film. As shown in Table 2, even in Examples 2-1 to 34, sequential biaxial stretching and simultaneous biaxial stretching are performed. By controlling the temperature immediately after stretching and the preheating temperature within an appropriate range, the display is uniform. A good quality film was obtained. On the other hand, in Comparative Example 2-1, the preheating temperature was lower than the temperature immediately after stretching, so the average value and variation of the orientation angle were in an inappropriate range, and the bowing distortion was also large. In Comparative Example 2-2, since the temperature immediately after stretching was higher than Tg, the orientation angle and bowing strain were in an inappropriate range. Since Comparative Example 2-3 had a low preheating temperature, the orientation angle and bowing strain were in an inappropriate range. Since Comparative Examples 2-4 and 5 had a large amount of residual solvent, the temperature immediately after stretching was higher than Tg, and thus the films had an inappropriate orientation angle and bowing strain.

Configuration diagram of a film manufacturing apparatus to which the present invention is applied Schematic showing the zone configuration of the transverse stretching process section Explanatory drawing explaining the effect | action of this invention Table showing the results of the examples Table showing the results of the examples

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Film, 10 ... Film forming process part, 20 ... Longitudinal stretch process part, 30 ... Lateral stretch process part, 40 ... Winding process part

Claims (12)

In the method for producing a thermoplastic film produced by stretching a thermoplastic film in the transverse direction,
A method for producing a thermoplastic film, wherein the step up to the tenter exit after the stretching is performed at a temperature not higher than the glass transition temperature.   The method for producing a thermoplastic film according to claim 1, wherein the film temperature before stretching is higher than the film temperature after stretching. In the method for producing a thermoplastic film produced by stretching a thermoplastic film in the transverse direction,
The method for producing a thermoplastic film, wherein the film temperature before stretching is higher than the film temperature after stretching.   The thermoplastic film before stretching is preheated, and the zone temperature at the time of preheating is maintained at -10 ° C or higher and + 30 ° C or lower with respect to the zone temperature at the time of stretching. The method for producing a thermoplastic film according to any one of the above.   5. The stretching according to claim 1, wherein the stretching is performed at least 1 to 2.5 times in a state where both ends in the width direction of the thermoplastic film are held by clips. A method for producing a thermoplastic film.   The orientation angle is within 0 ° ± 5 ° or within 90 ° ± 5 °, the magnitude of the bowing strain is within 10%, the in-plane retardation (Re) is from 0 nm to 500 nm, and the retardation in the thickness direction (Rth) is A thermoplastic film having a thickness of 30 nm to 500 nm.   The retardations Re and Rth each have a variation in the width direction and the longitudinal direction of 5% or less, and the orientation angle has a variation in the width direction and the longitudinal direction of 5 ° or less, respectively. Thermoplastic film.   The thermoplastic film according to claim 6 or 7, wherein the thermoplastic film is a cellulose acylate film or a saturated norbornene-based film. The thermoplastic film according to claim 8, wherein in the cellulose acylate film, the acylate group satisfies the following substitution degree.
2.5 ≦ A + B <3.0
1.25 ≦ B <3.0
A: Degree of substitution of acetate group B: Sum of substitution degree of propionate group, butyrate group, pentanoyl group, hexanoyl group   A polarizing plate comprising at least one layer of the cellulose acylate film according to claim 8.   An optical compensation film for a liquid crystal display plate, wherein the cellulose acylate film according to claim 8 or 9 is used as a substrate.   An antireflection film comprising the cellulose acylate film according to claim 8 as a substrate.

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