JP2009192723A - Method for manufacturing retardation film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a retardation film which includes a wide optical characteristic area and is more useful by using an ordinary tenter in which a clip interval cannot be adjusted in the longitudinal direction. <P>SOLUTION: In the method for manufacturing the retardation film for supplying a film 3 into the tenter 2, and clamping both edge parts of the film 3 with a plurality of clips 10 of tenter rails 5, 6 to stretch in the width direction of the film 3 in the tenter 2, the method for manufacturing the retardation film is characterized by releasing the edge parts of the film 3 from the clips 10 concurrently with completion of the stretching of the film 3 into the width direction, and cooling the film at the same time with releasing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a retardation film, and more particularly to a method for producing a retardation film having a wide optical property region by ordinary tenter stretching.

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

  As a method of stretching the thermoplastic film, a method of stretching in the longitudinal (longitudinal) direction (longitudinal stretching), a method of stretching in the lateral (width) direction (transverse stretching), or a method of sequentially performing longitudinal stretching and lateral stretching ( Sequential biaxial stretching).

  Of these, longitudinal stretching has been used in the past because of its compact equipment. Normally, longitudinal stretching is performed in the longitudinal direction by heating the film between two or more pairs of nip rolls to a glass transition temperature (Tg) or higher and increasing the transport speed on the outlet side to the transport speed of the nip roll on the inlet side. .

  In addition, a method of stretching in the width direction using a tenter is known for transverse stretching. By extending in the width direction, the optical axis is in the width direction, so that there is an advantage that the bonding with the polarizer can be performed by roll-to-roll.

  However, in the width direction stretching with a tenter, Rth / Re is 1 or more. Therefore, in order to produce a retardation film with Rth / Re less than 1, a free end uniaxial stretching method that does not constrain in the width direction is used. It was general.

  On the other hand, Patent Document 1 below describes a method for producing a retardation film using a simultaneous biaxial stretching apparatus capable of changing the clip interval in the longitudinal direction. By producing using such an apparatus, a retardation film having Rth / Re of 1 or less can be produced.

Patent Document 2 below discloses a method for producing a film in which biaxial stretching is performed in the longitudinal direction and the transverse direction by a tenter. According to this method, a manufacturing method is described in which when the film passes through the opening member, the interval between the clips 10 is expanded in the transport direction and the width direction. Thereby, a film can be extended | stretched simultaneously in the vertical direction and a horizontal direction.
JP 2007-108529 A JP 2006-69192 A

  However, the apparatus used in the methods described in Patent Documents 1 and 2 is large and economically disadvantageous.

  This invention is made | formed in view of such a situation, The manufacturing method of a more useful retardation film with a wide optical characteristic area | region is used using a normal tenter (the tenter which cannot adjust the clip interval of a longitudinal direction). The purpose is to provide.

  According to a first aspect of the present invention, in order to achieve the above object, a film is supplied into a tenter, and both ends of the film are gripped by a plurality of clips of a tenter rail in the tenter, and the width direction of the film In the method for producing a retardation film, the retardation of the retardation film is characterized by simultaneously releasing the film in the width direction and simultaneously releasing the end of the film from the clip and cooling the film. A manufacturing method is provided.

  According to the first aspect, the film is released from the clip at the same time as the stretching of the film in the width direction is completed. When the expansion angle in the width direction of the tenter rail is θ and the film conveyance speed (clip speed) at the tenter entrance is v, the film conveyance speed in the longitudinal direction when stretched in the width direction is v × cos θ. Thus, the conveying speed in the longitudinal direction is slower than before stretching in the width direction. Therefore, since the film can be shrunk in a direction (longitudinal direction) perpendicular to the stretching direction, a retardation film having Rth / Re of 1 or less can be produced.

  Moreover, the film is cooled at the same time as it is opened. Since the film is always transported in the longitudinal direction, when the clip is removed, the film is pulled in the running direction, so that the film is stretched in the longitudinal direction. Therefore, by cooling immediately after opening, the film is solidified, and by preventing the film from stretching, it is possible to maintain a state in which the film is contracted in the longitudinal direction.

  A second aspect of the present invention is characterized in that, in the first aspect, the end of the film is opened by removing the clip from the film or by cutting the end of the film.

  According to the second aspect, by removing the clip or cutting the end portion of the film, the film can be opened to produce a film having the desired optical characteristics. Therefore, it can manufacture using the tenter extending | stretching apparatus which cannot change a clip space | interval.

  A third aspect is characterized in that, in the first or second aspect, an expansion angle of the tenter rail is 5 ° or more and 40 ° or less.

  The third aspect defines the expansion angle of the tenter rail. By setting the spread angle in the above range, a desired Rth / Re retardation film can be produced. If the expansion angle of the tenter roll is narrower than 5 °, the film transport speed does not become slow, and no shrinkage in the running direction is observed. On the other hand, if the expansion angle is larger than 40 °, it is not preferable because it is suddenly stretched in the width direction from the open portion in the tenter. The spread angle is an angle formed by the running direction of the film in the tenter and the rail that extends the film in the width direction.

  A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the draw ratio in the width direction of the film is 1.2 times or more and 2.5 times or less.

  The fourth aspect defines the draw ratio in the width direction of the film. A favorable retardation film can be manufactured by making a draw ratio into the said range. If the draw ratio is lower than 1.2 times, the spread angle cannot be made sufficiently large. Or the extending | stretching part to the width direction in a tenter is short, the speed | rate of a running direction cannot be reduced, and the shrinkage | contraction to the longitudinal direction of a film is not seen. Further, if the stretching exceeds 2.5 times, the film may be broken during stretching, which is not preferable.

  A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the temperature during stretching is (Tg + 5) ° C. or higher and (Tg + 30) ° C. or lower, where Tg is the glass transition point of the film.

  The fifth aspect defines the temperature during stretching in the width direction. By setting the temperature within the above range, the fluidity of the film during stretching can be maintained and stretching in the width direction can be performed. If the temperature is lower than the above range, it is difficult to stretch because the film is solidified. If the temperature is higher than the above range, the fluidity of the film is too high to be formed easily. Since cooling takes time, it is not preferable.

  A sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the cooling is performed by a metal roll, and the temperature of the metal roll is controlled to be equal to or lower than Tg of the film.

  According to the sixth aspect, since the cooling of the film is performed using the metal roll whose temperature is controlled below the Tg of the film, it is possible to efficiently perform the cooling.

  A seventh aspect of the present invention according to the sixth aspect is characterized in that the metal roll is a drive roll capable of controlling a rotation speed at a constant speed.

  According to the seventh aspect, since the metal roll is a drive roll, it is possible to prevent the film from being stretched in the running direction after the clip is released by controlling the drive roll.

  An eighth aspect is characterized in that, in the sixth or seventh aspect, the surface of the metal roll is plated with hard chrome and mirror-finished.

  According to the eighth aspect, since the surface of the metal roll is plated with hard chrome, the film can be efficiently cooled and the film can be easily peeled off from the roll.

  Claim 9 is any one of claims 1 to 8, wherein the ratio of Re to Rth (Rth / Re) represented by the following formulas (1) and (2) is 0.6 or more and 0.9 or less, and Re is 40 nm to 300 nm and Rth is 25 nm to 270 nm

  Since the manufacturing method of the present invention is manufactured so as to be stretched in the width direction and contracted in the running direction, the retardation film having the optical characteristics as described above can be manufactured.

  A tenth aspect of the present invention is characterized in that, in any one of the first to ninth aspects, the film is made of cellulose acylate or a cyclic olefin resin.

  According to the tenth aspect, cellulose acylate or cyclic olefin is used as a film material. Cellulose acylate or cyclic olefin can be preferably used because it has moderate Re and Rth developability due to stretching, and stretch unevenness is hardly exhibited.

  According to the present invention, since the end of the film is opened at the same time as the stretching in the width direction is finished, the speed in the running direction is slow at the point where the clip is opened. Therefore, it is possible to produce a retardation film that is stretched in the width direction and contracted in the running direction, and in the stretching with a normal tenter device, the optical property area is wide, and a more useful retardation film can be produced.

  Hereinafter, preferred embodiments of a method for producing a retardation film of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a plan view of a tenter 2 for performing stretching in the width direction, which is a characteristic part of the present invention. The tenter 2 shown in the figure is a device that stretches in the width direction B while contracting in the traveling direction A while transporting the film 3 in the transport direction A, and includes two rails 5 and 6 and endless chains 7 and 8. I have. The two rails 5 and 6 are arranged on both sides with the film 3 interposed therebetween, and the distance between them is formed so that the downstream side is wider than the upstream side in the transport direction A.

  The endless chains 7 and 8 are respectively stretched between the driving sprockets 11 and 12 on the tenter inlet 16 side and driven sprockets 13 and 14 provided in the flow expanding portion 17 where the film expands in the width direction. 5 and 6 are arranged so as to be guided. By driving the driving sprockets 11 and 12, the endless chains 7 and 8 run around while being guided by the rails 5 and 6.

  A large number of clips 10, 10... Are attached to the endless chains 7, 8 at a predetermined pitch, and the side edges of the film 3 are gripped by the clips 10. The clip 10 moves together with the endless chains 7 and 8 by running the endless chains 7 and 8.

  Opening members 21 and 22 are attached to the aforementioned driving sprockets 11 and 12, respectively, and opening members 23 and 24 are attached to the driven sprockets 13 and 14, respectively. The opening members 21 to 24 are devices for displacing the flapper provided in the clip 10 from the holding position to the opening position, whereby the film 3 is automatically held and released by the flapper.

  In the tenter 2 configured as described above, when the endless chains 7 and 8 are run and the clips 10, 10... Are moved around, the clips 10 are in the open positions at the positions of the opening members 21 and 22. Then, the flapper becomes the gripping position by passing through the opening members 21 and 22, and both side edges of the film 3 are gripped. Each clip 10 gripping both side edges of the film 3 is expanded in the width direction B in the process of moving in the transport direction. Thereby, the film 3 is extended | stretched to a horizontal direction.

  At this time, if the expansion angle of the tenter rail is θ and the clip speed is v, the film conveyance speed is v before spreading in the width direction, and v × cos θ when the film is stretched in the width direction. It becomes. Accordingly, when the film 3 is stretched in the width direction, the transport speed becomes slow, and the film 3 contracts in the transport direction.

  After that, when the clip 10 is opened in a state where the film 3 is stretched in the width direction, that is, in a state where the conveyance speed is slow, the film 3 can be stretched in the width direction and form a film contracted in the running direction. it can.

  The clip 10 having opened the film 3 is returned to the upstream opening members 21 and 22, grips the film 3 again, and repeats this. By repeating the above operation, the film 3 is contracted in the vertical direction and stretched in the horizontal direction.

  As the configuration of the clip 10, a configuration similar to that of JP-A-2006-69192 can be used.

  In addition, the film is cooled by the cooling means (metal roll) 26 at the same time when the clip 10 is opened. Since the film is conveyed in the longitudinal direction, the film is always pulled in the longitudinal direction. Therefore, when the clip 10 opens the film 3, it is pulled in the longitudinal direction, and the meaning that the film is stretched and contracted in the longitudinal direction is lost. Therefore, by cooling at the same time as opening, the film can be solidified and prevented from stretching in the running direction.

  Examples of the cooling means 26 include a metal roll and a ceramic roll. Especially, it is preferable to cool with a metal roll. By cooling with a cooling roll, cooling can be performed efficiently. The cooling temperature is preferably a temperature of Tg or less. By setting the cooling temperature to Tg or less, the film can be solidified. Moreover, when performing using a cooling roll, it can carry out by controlling a cooling roll to the temperature below Tg.

  Furthermore, the surface of the metal roll is preferably plated and mirror-finished, and is preferably plated with hard chrome. By plating the surface of the metal roll, the film can be easily peeled off from the cooling roll.

  The metal roll 26 is preferably a drive roll so that the rotation speed can be controlled at a constant speed. In this invention, in order to prevent extending | stretching to a running direction, the film 10 is cooling simultaneously with the clip 10 releasing the film 3. FIG. However, since the film 3 is pulled in the longitudinal direction, this alone is not sufficient, and there are cases where the Re and Rth / Re ratios increase. Therefore, by using the metal roll 26 as a drive roll and controlling the conveyance speed of the film 3, stretching of the film in the traveling direction can be prevented. The rotation speed is preferably controlled so that the conveyance speed of the film 3 is v × cos θ.

  In addition, the nip roll 27 is preferably disposed so as to be in contact with the metal roll 26. By cooling and transporting while being nipped by the metal roll 26 and the nip roll 27, the film 3 can be transported at a stable speed. Further, it is preferable to cool the nip roll 27 through cooling water so that the nip roll 27 is not deteriorated by hot air.

  The stretching temperature when stretching in the width direction is preferably (Tg + 5) ° C. or more and (Tg + 30) ° C. or less, more preferably (Tg + 10) ° C. or more and (Tg + 20) ° C. or less. As a method for heating the film, a method of heating with hot air is preferable, and other methods such as heater heating and microwave heating may be used, and other heating methods may be used.

  Moreover, a preferable draw ratio is 1.2 to 2.5 times in the width direction, and more preferably 1.3 to 2.0 times. The method for producing a retardation film of the present invention is performed by opening a clip at the end point of the current spreading part in the current spreading part in the width direction in the tenter. Therefore, if the draw ratio in the width direction is less than 1.2 times, the spread angle is small and the speed change in the running direction is not sufficient, and if the spread angle is large, it is suddenly stretched in the width direction, which is not preferable. . On the other hand, if the draw ratio exceeds 2.5 times, the film may be broken by stretching, such being undesirable.

  The expansion angle of the tenter rail in the tenter is preferably 5 ° or more and 40 ° or less. By setting it as the said range, the difference of the speed change of a running direction becomes remarkable and a film can be shrunk in a running direction. Also, if the angle of expansion is less than 5 °, there will be no difference in speed change in the running direction, no shrinkage in the direction of travel will be observed, and if the angle of spread is larger than 40 °, it will be suddenly stretched in the width direction. Absent. The spread angle is an angle formed by the running direction of the film in the tenter and the rail that extends the film in the width direction, and is represented by θ in the figure.

  By stretching as described above, retardation Re and Rth can be expressed. The ratio of Re to Rth (Rth / Re) is preferably 0.6 or more and 0.9 or less. In other words, the difference in orientation between the vertical direction and the horizontal direction is the difference in retardation (Re) in the plane, but in the production method of the present invention, the film is stretched in the width direction and the vertical direction is the running direction. Since the contraction is performed, the difference between the vertical and horizontal orientations is increased, and the in-plane orientation (Re) can be increased.

  Further, Re is preferably 40 nm or more and 300 nm or less, and more preferably 45 nm or more and 270 nm or less. On the other hand, Rth is more preferably 25 nm or more and 270 nm or less, and more preferably 30 nm or more and 240 nm or less.

  Here, the retardations Re and Rth can be obtained by the following formulas (1) and (2).

  Next, the operation of this embodiment will be described.

  In the present invention, in the tenter 2, the clip 10 grips the side edge portion of the film 3 to perform horizontal stretching and vertical contraction, so that adhesion marks can be reduced. Therefore, minute display unevenness that occurs when the liquid crystal display device is incorporated as a retardation film can be reduced. Such an effect is particularly effective when a cellulose acylate film or a saturated norbornene film is used as the thermoplastic film. Since these resins are easy to stick on the nip roll used for stretching, the use of the method of the present invention can reduce sticking marks, which is very effective.

  In the present embodiment, in the tenter 2, the stretching ratio in the transverse direction can be adjusted by adjusting the distance between the rails when stretching in the width direction. Further, by adjusting the expansion angle of the tenter rail, the conveyance speed can be adjusted, and the contraction rate in the vertical direction of the film 3 can be adjusted. Therefore, Re and Rth can be set to arbitrary values, and a retardation film having desired optical characteristics can be produced.

  In addition, although embodiment mentioned above demonstrated the method to open | release the film 3 by removing the clip 10 from the film 3, opening by cut | disconnecting the side edge part of the film 3 hold | gripped by the clip 10. Is also possible. Examples of the cutting method include a method of cutting with a laser, a cutter or the like.

  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 for stretching described above is not particularly limited, it is preferably made of cellulose acylate or a cyclic olefin resin, and the cyclic olefin resin is a saturated norbornene resin. A resin is preferred. 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.

  In the present invention, it is preferable to reduce the substitution degree of the acetate group and increase the total substitution degree of the propionate group, butyrate group, pentanoyl group, and hexanoyl group. 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 diethylhexyl 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, glycerin oleate propionate, and 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 Specific examples of preferred diglycerin esters include diglycerin tetraacetate, diglycerin tetrapropionate, diglycerin tetrabutyrate, diglycerin tetravalerate, diglycerin tetrahexanoate, diglycerin tetraheptanoate, Diglycerin tetracaprylate, diglycerin tetrapelargonate, diglycerin tetracaprate, diglycerin tetralaurate, jig Glycerin tetraacetylate, diglycerin tetrapalmitate, diglycerin triacetate propionate, diglycerin triacetate butyrate, diglycerin triacetate valerate, diglycerin triacetate hexanoate, diglycerin triacetate heptanoate, diglycerin triacetate caprylate, Diglycerol triacetate pelargonate, diglycerol triacetate caprate, diglycerol triacetate laurate, diglycerol triacetate myristate, diglycerol triacetate palmitate, diglycerol triacetate stearate, diglycerol triacetate oleate, diglycerol diacetate dipropionate, di Glycerin diacetate dibutyrate, diglycerin Diacetate divalerate, diglycerin diacetate dihexanoate, diglycerin diacetate diheptanoate, diglycerin diacetate dicaprylate, diglycerin diacetate dipelargonate, diglycerin diacetate dicaprate, diglycerin di Acetate dilaurate, diglycerol diacetate dimyristate, diglycerol diacetate dipalmitate, diglycerol diacetate distearate, diglycerol diacetate diolate, diglycerol acetate tripropionate, diglycerol acetate tributyrate, diglycerol Acetate trivalerate, diglycerol acetate trihexanoate, diglycerol acetate triheptanoate, diglycerol acetate tricaprylate Diglycerin Acetate Tripelargonate, Diglycerol Acetate Tricaprate, Diglycerol Acetate Trilaurate, Diglycerol Acetate Trimyristate, Diglycerol Acetate Tripalmitate, Diglycerol Acetate Tristearate, Diglycerol Acetate Trioleate, Diglycerin Laut Examples include, but are not limited to, diglycerin stearate, diglyceryl caprylate, diglycerin myristate, diglycerin mixed acid esters of diglycerin oleate, etc., 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 a 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 combination of two or more. As specific examples of the phosphite stabilizers, 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 added 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, and 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.

  Examples of benzotriazoles include TINUBIN P (Ciba Specialty Chemicals), TINUBIN 234 (Ciba Specialty Chemicals), TINUBIN 320 (Ciba Specialty Chemicals), TINUBIN 326 (Ciba Specialty Chemicals), and TINUBIN 327 (Ciba Specialty Chemicals). Specialty Chemicals), TINUBIN 328 (Ciba Specialty Chemicals), and Sumsorb 340 (Sumitomo Chemical). Further, as benzophenone-based ultraviolet absorbers, 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) and the like. Examples of oxalic acid anilide UV absorbers include TINUBIN 312 (Ciba Specialty Chemicals) and TINUBIN 315 (Ciba Specialty Chemicals). Further, as a salicylic acid-based ultraviolet absorber, Seesorb 201 (Cipro Kasei) and Seesorb 202 (Cipro Kasei) are marketed, and as a cyanoacrylate-based UV absorber, Seesorb 501 (Cipro Kasei), UVINUL N-539 (BASF). 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, etc. Polar group substitution products such as halogens; 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. The ester, ketone and ether 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 portion is re-processed 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 subjected to processing such as granulation or depolymerization / repolymerization 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 can be stretched by the above method to obtain the thermoplastic film of the present invention.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

Example 1
The TAC film, which is the original film, was prepared by solution casting with the addition of 5% of a retardation developer. After producing the film, the film was stretched in the width direction using the tenter shown in FIG. The film conveyance speed was 5 m / min, and the clip was opened immediately after stretching, as shown in FIG. Then, it cooled with the mirror surface roll, driving a roll. The expansion angle of the tenter rail of the apparatus was 15 °, and stretching was performed so that the stretching ratio in the width direction was 1.5 times. The temperature during stretching was 150 ° C. (TAC film Tg: 140 ° C.). The results are shown in FIG. The optical characteristics in the figure were judged according to the following criteria.

[optical properties]
A: Re is 40 nm to 300 nm, Rth is 25 nm to 270 nm, and Rth / Re <0.7.
B: Re is 40 nm to 300 nm, Rth is 25 nm to 270 nm, and Rth / Re <0.8.
Δ: Re is 40 nm to 300 nm, Rth is 25 nm to 270 nm, and Rth / Re ≦ 0.9.
X: Re is lower than 40 nm or higher than 300 nm, Rth is lower than 25 nm or higher than 270 nm, or Rth / Re> 0.9.

<< Examples 2 to 8 >>
A film was produced by the same method as in Example 1 with the apparatus conditions and stretching conditions changed to the conditions shown in FIG. In Example 8, a TOPAS film was used as the original film. The TOPAS film was produced by melting and forming a resin of commercially available TOPAS 6013 (manufactured by Polyplastics Co., Ltd.).

≪Comparative Examples 1 and 2≫
The tenter was stretched in the width direction using a normal tenter as shown in FIG. 1 of JP-A-2006-69192, and the clip was opened after the film was cooled. The film was cooled by blowing cool air over the film. About the conditions of an apparatus and extending | stretching conditions, it carried out on the conditions shown in FIG. The results are shown in FIG.

≪Result≫
As shown in FIG. 2, Comparative Examples 1 and 2 in which the clip was opened after cooling were not contracted in the longitudinal direction, and Rth / Re exceeded 0.9. However, in Examples 1 to 8 in which the clip was opened immediately after stretching and then cooled, the longitudinal stretching was suppressed and Rth / Re could be reduced to 0.9 or less. In particular, the mirror roll is a drive roll, the tenter rail spread angle is 5 ° to 40 °, the stretching temperature is 150 ° C., and (Tg−5) ° C. to (Tg−20) ° C. In Examples 1 and 8, particularly good results were obtained.

It is a top view of the tenter used for the manufacturing method of the present invention. It is a table | surface figure which shows the test conditions of an Example, and a result.

Explanation of symbols

  2 ... Tenter, 3 ... Film, 5, 6 ... Rail, 7,8 ... Endless chain, 10 ... Clip, 11, 12 ... Primary sprocket, 13, 14 ... Driving sprocket, 16 ... Tenter inlet, 17 ... Expansion part, 21, 22, 23, 24 ... opening member, 26 ... cooling means (metal roll), 27 ... nip roll

Claims (10)

In the method for producing a retardation film in which a film is supplied into a tenter, and both ends of the film are held by a plurality of clips of a tenter rail and stretched in the width direction of the film in the tenter.
A method for producing a retardation film, comprising: releasing the end of the film from the clip at the same time as the stretching of the film in the width direction is completed, and cooling the film.   2. The method for producing a retardation film according to claim 1, wherein the end of the film is opened by removing the clip from the film or by cutting the end of the film.   The method for producing a retardation film according to claim 1, wherein an expansion angle of the tenter rail is 5 ° or more and 40 ° or less.   The method for producing a retardation film according to any one of claims 1 to 3, wherein a draw ratio in a width direction of the film is 1.2 times or more and 2.5 times or less.   5. The retardation film according to claim 1, wherein the temperature during stretching is (Tg + 5) ° C. or more and (Tg + 30) ° C. or less when the glass transition point of the film is Tg. Production method.   The method for producing a retardation film according to claim 1, wherein the cooling is performed by a metal roll, and the temperature of the metal roll is controlled to Tg or less of the film.   The method for producing a retardation film according to claim 6, wherein the metal roll is a drive roll capable of controlling a rotation speed at a constant speed.   The method for producing a retardation film according to claim 6 or 7, wherein a surface of the metal roll is plated with hard chrome and is mirror-finished. The ratio of Re and Rth (Rth / Re) represented by the following formulas (1) and (2) is 0.6 or more and 0.9 or less, Re is 40 nm or more and 300 nm or less, and Rth is 25 nm or more and 270 nm or less. The method for producing a retardation film according to claim 1, wherein:

  The method for producing a retardation film according to claim 1, wherein the film is made of a cellulose acylate or a cyclic olefin-based resin.

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