JP2016007803A - Method and apparatus for production of resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for production of a resin film which achieves uniformity of the film thickness and good productivity while keeping good releasability by using a cooling technique based on air blow.SOLUTION: A production apparatus of a resin film comprises a die 2 which extrudes a molten resin composition 10, a first roll 3 and a second roll 4 which are arranged under the discharge port 2a of the die 2 and sandwich the resin composition 10 extruded from the discharge port 2a, a blowing member 5 which jets air onto the first roll 3 and a control plate 6 which is provided on a passage for the air jetted by the blowing member 5 and controls the air flow of the air. While air is jetted onto the first roll 3, the control plate 6 prevents inflow of air into an air gap from the discharge port 2a to between the first roll 3 and the second roll 4.

Description

  The present invention relates to a method for producing a resin film, and more particularly, to a method for producing a thermoplastic resin film formed by a melt extrusion molding method, and an apparatus for producing a resin film.

  In recent years, an optical film made of a thermoplastic resin film manufactured by melt extrusion molding has been required to have high quality without phase difference unevenness. For this reason, when manufacturing a resin film, the uniformity of the thickness of the film is required with high accuracy. One of the causes of unevenness in the thickness of the resin film in melt extrusion molding is a film shake of the molten resin sheet in a region between the die and the cooling roll (hereinafter referred to as “air gap”).

  In general, in a resin film manufacturing process by melt extrusion molding, a molten resin extruded into a sheet shape is pressed by a nip roll in order to perform surface treatment such as glazing on the resin film and shape transfer. At this time, the nip roll needs to be cooled in order to ensure that the resin film surface can be peeled off from the nip roll without causing streaks or the like. As a cooling method for the nip roll, an internal method in which the cooling means is provided inside the roll and an external method in which the cooling means is provided outside the roll are conceivable. In the internal method, the heat of the devices constituting the nip roll and the cooling means is considered. Since the cooling efficiency varies depending on the conductivity or the like, a cooling method using an external method such as air blow is generally employed.

JP 2014-35383 A Japanese Patent No. 4088135 Japanese Patent No. 4277531

  However, in the cooling method by air blow, the injected air flows on the surface of the nip roll and wraps around the air gap, and at the interface of the molten resin sheet extruded from the die, the air wraps around the area and vice versa. A difference in atmospheric pressure is generated in the region on the side, causing fluctuations in film thickness.

  The film thickness variation can be dealt with to some extent by reducing the molding speed of the resin film, but the tact lengthens and the productivity is poor.

  Patent Document 2 discloses a technique for controlling film thickness variation by controlling the air gap distance. According to the method described in Patent Document 2, the film thickness variation caused by the draw resonance can be controlled by the air gap distance, but when cooling by an external method using air blow, it is affected by the air, and the sufficient effect is obtained. Cannot be obtained. Further, when pressing with a nip roll, a problem arises in that a dedicated die shape is required due to the positional relationship between the roll and the die, and control with a general-purpose device cannot be performed.

  Further, Patent Document 3 discloses a technique for reducing the film thickness variation by surrounding the die periphery with negative pressure and blowing air controlled at a predetermined speed and temperature to the air gap. However, since the technique described in Patent Document 3 applies a negative pressure around the die and blows air controlled at a predetermined speed and temperature, it is not possible to use sufficient air for cooling, and cooling the nip roll. Becomes insufficient and the peelability is impaired. Further, if the molding speed is lowered to improve the peelability, the tact time is extended and the productivity is inferior.

  Therefore, the present invention provides a resin film manufacturing method and a resin film manufacturing apparatus having uniformity in film thickness and productivity while maintaining good releasability using a cooling method by air blow. For the purpose.

  In order to solve the above-described problems, a method for producing a resin film according to the present invention includes a die that extrudes a molten resin composition, and the resin that is disposed below the discharge port of the die and is extruded from the discharge port. A first roll and a second roll for sandwiching the composition; a blower member for injecting air to the first roll; and a flow path of air jetted from the blower member; An air gap that extends between the first roll and the second roll from the discharge port of the air by the control plate while jetting air to the first roll. Is to prevent the inflow of water.

  The apparatus for producing a resin film according to the present invention includes a die that extrudes a molten resin composition, and a first that is disposed below a discharge port of the die and sandwiches the resin composition extruded from the discharge port. And a second roll, a blower member that jets air to the first roll, and a control plate that is provided on the flow path of the air jetted from the blower member and controls the airflow of the air. Then, while the air is ejected to the first roll, the control plate prevents the air from flowing between the discharge port, the first roll, and the second roll.

  According to this invention, it has favorable peelability of a resin film by cooling a 1st roll with a ventilation member. In addition, the present invention provides a control plate and controls the air flow blown from the blower member, thereby suppressing the amount of fluctuation of atmospheric pressure in the air gap to an appropriate range, and achieving highly uniform film thickness uniformity. The resin film which has is obtained. Furthermore, the present invention does not impair these peelability and film thickness accuracy even when the molding speed is increased.

FIG. 1 is a diagram showing a schematic configuration of a film manufacturing apparatus to which the present invention is applied. FIG. 2 is a diagram showing a schematic configuration of another film manufacturing apparatus to which the present invention is applied. FIG. 3 is a cross-sectional perspective view showing an outline of a cyclic olefin-based resin composition film shown as an example of a resin film.

  Hereinafter, a resin film manufacturing method and a resin film manufacturing apparatus to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the present invention. Further, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Specific dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  As shown in FIG. 1, an apparatus 1 for producing a resin film 11 to which the present invention is applied is disposed below a die 2 for extruding a molten resin composition, and a discharge port 2a of the die 2, and the film is formed from the discharge port 2a. The first roll 3 and the second roll 4 that sandwich the extruded resin composition 10, the blowing member 5 that jets air to the first roll 3, and the flow of air jetted from the blowing member 5 And a control plate 6 provided on the road for controlling the air flow.

[Die]
The die 2 is for extruding the molten resin composition 10 constituting the resin film 11 into a film shape from the discharge port 2a, and a general T-die for melt molding can be used.

[First and second rolls]
After the 1st and 2nd rolls 3 and 4 are oppositely arranged below the discharge port 2a of the die 2 and cooled by sandwiching the resin composition 10 extruded from the discharge port 2a, the film is formed into a film shape. To transport. The first and second rolls 3 and 4 are configured to be rotatable at an arbitrary rotation speed ratio by a rotational power transmission mechanism (not shown). The surface shapes of the first and second rolls 3 and 4 are not particularly limited, and can be arbitrarily selected, for example, a mirror surface, a textured surface, a prism, a lenticular, or the like. Moreover, the material of the surface of the 1st, 2nd rolls 3 and 4 is not specifically limited, For example, a metal, rubber | gum, resin, an elastomer, etc. can be selected arbitrarily. In addition, the 1st, 2nd rolls 3 and 4 are equipped with a temperature adjustment mechanism inside, and may be made to be able to adjust surface temperature arbitrarily, respectively.

[Blowing member]
The blower member 5 cools the surface of the first roll 3 by injecting air onto the first roll 3 to achieve both the peelability of the resin film 11 and the productivity. An air knife that jets air uniformly over the width direction of the surface of the roll 3 can be used. Air, nitrogen, or the like can be used as the air ejected from the blowing member 5.

  As shown in FIG. 1, the air blowing member 5 is provided on the side opposite to the side where the die 2 of the first roll 3 is provided, and the side where the air faces the second roll 4 of the first roll 3 It is preferable to flow on the opposite side. Thereby, the flow path through which the air ejected from the air blowing member 5 travels on the surface of the first roll 3 can be ensured for a long time and can be effectively cooled. In addition, the first roll 3 is sandwiched and heated by the resin composition 10 and then air-cooled by the air ejected from the blower member 5, and then the resin composition 10 can be sandwiched again in a film shape. The peelability of the molded resin composition 10 becomes good.

[Control board]
The control plate 6 controls the flow of air ejected from the blower member 5, and the shape, material, etc. are not particularly limited. By providing the control plate 6, the film manufacturing apparatus 1 can change the atmospheric pressure in the air gap between the die 2 and the first and second rolls 3 and 4 due to the airflow that travels on the surface of the first roll 3. To prevent.

  That is, in the melt extrusion manufacturing method, if an air flow is generated on one side of the discharge port of the die in the air gap and a pressure difference is generated on both sides of the extruded resin composition 10, the film shakes in the air gap and the film thickness varies. . Therefore, the film manufacturing apparatus 1 ejects from the blower member 5 arranged below the first roll 3 by arranging the control plate 6 above the first roll 3 as shown in FIG. Thus, the air flowing along the left side surface in the figure opposite to the side surface facing the second roll 4 of the first roll 3 is prevented from flowing into the air gap. Thereby, in the air gap, the atmospheric pressure difference on both sides of the resin composition 10 is within an appropriate range, and the resin composition 10 has a substantially uniform thickness with little film thickness variation. Therefore, in the optical film which consists of a thermoplastic resin film manufactured using the film manufacturing apparatus 1, it has high quality without phase difference unevenness.

  Here, the amount of pressure fluctuation on both sides of the film-like resin composition 10 required to suppress film thickness fluctuation due to film shaking of the film-like resin composition 10 in the air gap depends on the resin composition, the speed of extrusion molding, etc. However, from the viewpoint of achieving both the forming speed that satisfies the productivity and the uniformity of the film thickness, for example, ± 2 Pa or less is preferable.

  It is preferable that the control plate 6 is disposed so as to face the air blowing member 5 and the first roll 3. This ensures a long flow path length through which the air ejected from the blower member 5 flows on the surface of the first roll 3, effectively cools the surface of the first roll 3, and allows a large air gap in the airflow. The fluctuation of the atmospheric pressure can be controlled within an appropriate range (for example, less than ± 2 Pa).

  Further, as shown in FIG. 2, the control plate 6 is provided at a position offset from the position facing the air blowing member 5 via the first roll 3 to the side opposite to the side facing the second roll 4. Also good. Since the control plate 6 is separated from the discharge port 2a of the die 2 through the top of the first roll 3 by being provided at the position, the molten resin composition 10 is scattered and adhered, The adhered resin composition 10 can be prevented from adhering to the first roll 3 and fouling the roll surface.

[Resin film]
Here, as the resin film 11 manufactured with the film manufacturing apparatus 1, the various films used for an optical film, a packaging film, etc. are mentioned. Here, as the resin film 11, a cyclic olefin resin composition film in which an elastomer or the like is added and dispersed in a cyclic olefin resin is illustrated. Cyclic olefin resin is an amorphous and thermoplastic olefin resin that has a cyclic olefin skeleton in its main chain, has excellent optical properties (transparency, low birefringence), low water absorption, It has excellent performance such as dimensional stability and high moisture resistance. Therefore, a film or sheet made of a cyclic olefin resin can be used for various optical applications, for example, a retardation film, a polarizing plate protective film, a light diffusion plate, etc., particularly a prism sheet, a liquid crystal cell substrate, and a moisture-proof packaging. Applications to applications such as pharmaceutical packaging and food packaging are also expected.

  Further, as shown in FIG. 3, the cyclic olefin-based resin film 11 is obtained by adding and dispersing a styrene-based elastomer 13 having a hard segment and a soft segment in a predetermined ratio in the cyclic olefin-based resin 12. It has excellent retardation and haze) and sufficient toughness.

[Cyclic olefin resin]
The cyclic olefin-based resin 12 is a polymer compound having a main chain composed of a carbon-carbon bond and having a cyclic hydrocarbon structure in at least a part of the main chain. This cyclic hydrocarbon structure is introduced by using a compound (cyclic olefin) having at least one olefinic double bond in the cyclic hydrocarbon structure as represented by norbornene or tetracyclododecene as a monomer. Is done.

  Cyclic olefin resins include cyclic olefin addition (co) polymers or hydrogenated products thereof (1), cyclic olefin and α-olefin addition copolymers or hydrogenated products thereof (2), cyclic olefin ring-opening ( Co) polymers or hydrogenated products thereof (3).

  Specific examples of the cyclic olefin include: cyclopentene, cyclohexene, cyclooctene; one-ring cyclic olefin such as cyclopentadiene, 1,3-cyclohexadiene; bicyclo [2.2.1] hept-2-ene (common name: norbornene) ), 5-methyl-bicyclo [2.2.1] hept-2-ene, 5,5-dimethyl-bicyclo [2.2.1] hept-2-ene, 5-ethyl-bicyclo [2.2. 1] Hept-2-ene, 5-butyl-bicyclo [2.2.1] hept-2-ene, 5-ethylidene-bicyclo [2.2.1] hept-2-ene, 5-hexyl-bicyclo [ 2.2.1] hept-2-ene, 5-octyl-bicyclo [2.2.1] hept-2-ene, 5-octadecyl-bicyclo [2.2.1] hept-2-ene, 5- Methylidene Bicyclo [2.2.1] hept-2-ene, 5-vinyl-bicyclo [2.2.1] hept-2-ene, 5-propenyl-bicyclo [2.2.1] hept-2-ene, etc. A bicyclic olefin of

Tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene), tricyclo [4.3.0.1 ^2,5 ] dec-3-ene; tricyclo [ 4.4.0.1 ^2,5 ] undeca-3,7-diene or tricyclo [4.4.0.1 ^2,5 ] undeca-3,8-diene or a partially hydrogenated product thereof (or cyclopentadiene) Tricyclo [4.4.0.1 ^2,5 ] undec-3-ene; 5-cyclopentyl-bicyclo [2.2.1] hept-2-ene, 5-cyclohexyl-bicyclo [2.2.1] hept-2-ene, 5-cyclohexenylbicyclo [2.2.1] hept-2-ene, 5-phenyl-bicyclo [2.2.1] hept-2-ene A cyclic olefin of the ring;

Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (also simply referred to as tetracyclododecene), 8-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-vinyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-propenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] tetracyclic olefins such as dodec-3-ene;

8-cyclopentyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-cyclohexyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-cyclohexenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-phenyl-cyclopentyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene; tetracyclo [7.4.1 ^3,6 . 0 ^1,9 . 0 ^2,7 ] tetradeca-4,9,11,13-tetraene (also referred to as 1,4-methano-1,4,4a, 9a-tetrahydrofluorene), tetracyclo [8.4.1 ^4,7 . 0 ^1,10 . 0 ^3,8 ] pentadeca-5,10,12,14-tetraene (also called 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene); pentacyclo [6.6.1]. ^.1,3,6 . 0 ^2,7 . 0 ^9,14 ] -4-hexadecene, pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13] -4-pentadecene, pentacyclo [7.4.0.0 ^2,7. 1 ^3,6 . 1 ^10,13] -4-pentadecene; heptacyclo [8.7.0.1 ^2,9. 1 ^4,7 . 1 ^{11, 17} . 0 ^3,8 . 0 ^12,16 ] -5-eicosene, heptacyclo [8.7.0.1 ^2,9 . 0 ^3,8 . 1 ^4,7 . 0 ^12,17 . 1 ^13,16 ] ^-14-eicosene ; and polycyclic cyclic olefins such as a tetramer of cyclopentadiene. These cyclic olefins can be used alone or in combination of two or more.

  Specific examples of the α-olefin copolymerizable with the cyclic olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3 -Ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1- 2-20 carbon atoms such as hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, preferably carbon number Examples include 2 to 8 ethylene or α-olefin. These α-olefins can be used alone or in combination of two or more. As these α-olefins, those contained in the range of 5 to 200% with respect to the cyclic polyolefin can be used.

  There are no particular limitations on the polymerization method of the cyclic olefin or the cyclic olefin and the α-olefin and the hydrogenation method of the obtained polymer, and it can be carried out according to a known method.

  As the cyclic olefin resin 12, an addition copolymer of ethylene and norbornene is preferably used in the present embodiment.

  The structure of the cyclic olefin-based resin 12 is not particularly limited, and may be chain-like, branched or cross-linked, but is preferably linear.

  The molecular weight of the cyclic olefin-based resin 12 is 5,000 to 300,000, preferably 10,000 to 150,000, and more preferably 15,000 to 100,000 according to the GPC method. If the number average molecular weight is too low, the mechanical strength decreases, and if it is too high, the moldability deteriorates.

  In addition, the cyclic olefin resin 12 includes a polar group (for example, a carboxyl group, an acid anhydride group, an epoxy group, an amide group, an ester group, a hydroxyl group, etc.) in addition to the above-mentioned cyclic olefin resins (l) to (3). Grafted and / or copolymerized (4) of an unsaturated compound (u) having Two or more of the cyclic olefin resins (l) to (4) may be used in combination.

  Examples of the unsaturated compound (u) include (meth) acrylic acid, maleic acid, maleic anhydride, itaconic anhydride, glycidyl (meth) acrylate, alkyl (meth) acrylate (carbon number 1 to 10) ester, maleic acid Alkyl (C1-C10) ester, (meth) acrylamide, (meth) acrylic acid-2-hydroxyethyl, etc. are mentioned.

  Affinity with metals and polar resins can be increased by using a modified cyclic olefin resin (4) obtained by grafting and / or copolymerizing an unsaturated compound (u) having a polar group, so vapor deposition, sputtering, coating It is possible to increase the strength of various secondary processing such as adhesion, and is suitable when secondary processing is required. However, the presence of the polar group has a drawback of increasing the water absorption rate of the cyclic olefin resin. Therefore, the content of polar groups (for example, carboxyl group, acid anhydride group, epoxy group, amide group, ester group, hydroxyl group, etc.) is preferably 0 to 1 mol / kg per kg of cyclic olefin resin.

[Styrene elastomer]
The styrene elastomer 13 has a storage elastic modulus at 0 ° C. to 100 ° C. of less than 100 MPa. That is, the maximum value of the storage elastic modulus at 0 ° C. to 100 ° C. of the styrene elastomer 13 is less than 100 MPa. A more preferred storage elastic modulus is 20 MPa or less. When the storage elastic modulus at 0 ° C. to 100 ° C. is large, the in-plane retardation of the film becomes large.

  Two types of factors are involved in polymer birefringence. The first is orientation refraction that occurs when molecular chains are highly oriented. Orientation refraction is determined by the degree of orientation and the intrinsic value of the polymer main chain. The second is birefringence due to stress. When force is applied from the outside, the birefringence changes due to the distortion.

  The styrenic elastomer 13 has a low-energy-condensed yarn-like shape when no external force is applied, but when an external force such as stretching or shearing is applied, the molecular chain is thereby stretched and oriented in one direction. become. The optical properties (refractive index) are different between the main chain and the direction crossing the main chain, and a product in which molecular chains are highly oriented exhibits a so-called birefringence phenomenon.

  In the present embodiment, since the storage elastic modulus of the styrene elastomer 13 at 0 ° C. to 100 ° C. is less than 100 MPa, the fluidity at the time of melting is high, the residual stress can be reduced, and the orientation of the molecular chain It is possible to keep the degree small. In addition, it is considered that the intrinsic refractive index can be reduced by including the negative refractive index of the styrene portion and the positive refractive index of the ethylene portion.

  The molecular weight of the styrene-based elastomer 13 is 5,000 to 300,000, preferably 10,000 to 150,000, and more preferably 20,000 to 100,000 according to the GPC method. If the number average molecular weight is too low, the mechanical strength decreases, and if it is too high, the moldability deteriorates.

  The styrene elastomer 13 is a copolymer of styrene and a conjugated diene such as butadiene or isoprene, and / or a hydrogenated product thereof. The styrene elastomer 13 is a block copolymer having styrene as a hard segment and conjugated diene as a soft segment. The structure of the soft segment changes the storage elastic modulus of the styrene-based elastomer 13, and the content of styrene as the hard segment changes the refractive index and changes the haze of the entire film. The styrene elastomer 13 does not require a vulcanization step and is preferably used. Further, the hydrogenated one is more preferable because it has higher thermal stability.

  Examples of styrenic elastomers 13 include styrene / butadiene / styrene block copolymers, styrene / isoprene / styrene block copolymers, styrene / ethylene / butylene / styrene block copolymers, and styrene / ethylene / propylene / styrene block copolymers. Examples thereof include a polymer and a styrene / butadiene block copolymer.

  In addition, styrene / ethylene / butylene / styrene block copolymer, styrene / ethylene / propylene / styrene block copolymer, styrene / butadiene block copolymer (hydrogenation) in which double bond of conjugated diene component is eliminated by hydrogenation May also be used.

  The structure of the styrene-based elastomer 13 is not particularly limited, and may be chain-like, branched or cross-linked, but is preferably linear in order to reduce the storage elastic modulus.

  In the present embodiment, at least one styrene selected from the group consisting of styrene / ethylene / butylene / styrene block copolymers, styrene / ethylene / propylene / styrene block copolymers, and hydrogenated styrene / butadiene block copolymers. A system elastomer 13 is preferably used. In particular, hydrogenated styrene / butadiene block copolymers are more preferably used because of high tear strength and small haze increase after environmental preservation. The ratio of butadiene to styrene in the hydrogenated styrene / butadiene block copolymer is preferably in the range of 10 to 90% so as not to impair the compatibility with the cyclic olefin resin.

  Moreover, it is preferable that the styrene content rate of the styrene-type elastomer 13 is 20-40 mol%. By setting the styrene content to 20 to 40 mol%, the haze can be reduced.

  In addition to the cyclic olefin-based resin 12 and the styrene-based elastomer 13, various compounding agents may be added to the cyclic olefin-based resin composition as necessary as long as the characteristics thereof are not impaired. The various compounding agents are not particularly limited as long as they are usually used in thermoplastic resin materials. For example, antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, lubricants, antistatic agents, difficulty Examples include flame retardants, colorants such as dyes and pigments, near infrared absorbers, compounding agents such as fluorescent brighteners, and fillers.

  According to the cyclic olefin-based resin film 11 having such a configuration, the tear strength can be 60 N / mm or more, preferably 100 N / mm or more, and more preferably 120 N / mm or more. Further, the haze can be 15% or less, preferably 2% or less. If the tear strength is too smaller than the above range, the film is liable to break during production or use, which is inappropriate. On the other hand, if the haze is too high, it deviates from the initial characteristics in use and does not satisfy the intended characteristics.

[Method for Producing Cyclic Olefin Resin Film]
In the method for producing the cyclic olefin resin film 11 according to the present embodiment, the cyclic olefin resin 12 and the styrene elastomer 13 whose storage elastic modulus at 0 to 100 ° C. is less than 100 MPa are melted and melted. The obtained cyclic olefin resin composition is extruded into a film by an extrusion method to obtain a cyclic olefin resin film 11 in which the styrene elastomer 13 is dispersed in the cyclic olefin resin 12. The cyclic olefin resin film 11 may be non-stretched, uniaxially stretched, or biaxially stretched.

[Manufacturing process]
Subsequently, the manufacturing process of the resin film 11 using the film manufacturing apparatus 1 is demonstrated. First, the resin composition 10 serving as a resin material constituting the resin film 11 is put into the die 2 and brought into a molten state at a predetermined temperature, and then extruded into a film form from the discharge port 2a. The extruded resin composition 10 is sandwiched between first and second rolls 3 and 4 rotating at a predetermined rotational speed. The resin composition 10 is cooled by being sandwiched between the first and second rolls 3 and 4, and becomes a resin film 11 by being formed into a film shape. The resin film 11 is guided while being guided by a second roll and guided by a pinch roller or the like (not shown), and is wound into a roll shape to form an original roll.

  When increasing the molding speed to improve productivity, the amount of the resin composition 10 extruded from the die 2 is increased, and the first and second rolls 3 and 4 are driven at a peripheral speed corresponding to the discharge amount. And then cool forming. Moreover, the traveling system which winds up the resin film 11 in a roll shape also conveys the resin film at a speed corresponding to the discharge amount.

  Such a film manufacturing apparatus 1 is provided with the blower member 5 that cools the surface of the first roll 3 that sandwiches the resin composition 10, thereby reducing the surface temperature of the first roll 3 that sandwiches the resin composition 10. The rise can be suppressed. Here, the film manufacturing apparatus 1 is configured such that the resin composition 10 is sandwiched between the heated first rolls, and the resin film 11 is peeled off from the first roll 3 in an uncooled state, whereby the surface of the resin film 11 is obtained. Streaks appear on the surface and the appearance is damaged. In this respect, since the film manufacturing apparatus 1 cools the first roll 3 by the blower member 5, no streaks appear even when the resin film 11 is peeled off from the first roll 3. Has peelability.

  Moreover, the film manufacturing apparatus 1 arrange | positions the control board 6 which prevents the influence by the airflow of the ventilation member 5 on the air flow path of the ventilation member 5. FIG. Therefore, the film manufacturing apparatus 1 can control the fluctuation of the atmospheric pressure in the air gap within an appropriate range by the airflow from the blowing member 5, and can prevent the film thickness variation of the resin film 11.

  And even if it raises a shaping | molding speed, the film manufacturing apparatus 1 does not impair the said peelability and film thickness precision, maintaining the favorable peelability using the cooling method by the ventilation member 5, Thickness uniformity and productivity can be achieved at the same time.

  In addition, although the film manufacturing apparatus 1 provided the ventilation member 5 and the control board 6 in the 1st roll 3 side, according to the conveyance path | route of the resin film 11, the 2nd roll 4 side or 1st, 2nd The air blowing member 5 and the control plate 6 may be provided on each of the rolls 3 and 4.

  Next, examples of the present invention will be described. In this embodiment, a rubber nip roll having a rubber-wrapped surface around a metal core is used as a first roll for sandwiching the resin composition 10 extruded in a film shape, and a metal roll as a second roll. Was used. The surface temperature of the first roll is adjusted to 60 ° C., and the surface temperature of the second roll is adjusted to 40 ° C. Further, norbornene resin (glass transition temperature Tg: 170 ° C.) was used as the material of the resin film 11.

  This resin material was extruded from a die into a film having a thickness of 100 μm, and niped with first and second rolls to obtain a retardation film.

[Example 1]
In Example 1, while providing an air knife as a ventilation member, the control board which controls the airflow by the air which ejected from the air knife was installed. The air knife and the control plate were arranged to face each other via the first roll (see FIG. 1). In Example 1, the molding speed was 20 m / min, and the air knife was operated at a wind speed of 25.4 m / s.

[Example 2]
In Example 2, the molding conditions were the same as in Example 1 except that the air knife was operated at a wind speed of 35.6 m / s.

[Comparative Example 1]
In Comparative Example 1, the air blowing member and the control plate were not provided. In Comparative Example 1, the molding speed was 5 m / min.

[Comparative Example 2]
In Comparative Example 2, the same molding conditions as in Comparative Example 1 were used except that the molding speed was 20 m / min.

[Comparative Example 3]
In Comparative Example 3, an air knife was provided as a blowing member, but no control plate was provided. The air knife was placed below the first roll (see FIG. 1). In Comparative Example 3, the same molding conditions as in Comparative Example 2 were used except that the air knife was operated at a wind speed of 25.4 m / s.

[Pressure fluctuation]
In the manufacturing process of the retardation film according to each example and comparative example described above, the differential pressure and the amount of fluctuation of the atmospheric pressure on the first roll side with respect to the atmospheric pressure on the second roll side in the air gap were measured. A pressure fluctuation of less than ± 2 Pa was evaluated as ◯ (good), and a pressure fluctuation of ± 2 Pa or higher was evaluated as × (bad).

[Molding speed]
The molding speed was evaluated as ◯ (good) when 10 m / min or more, and x (defective) when less than 10 m / min.

[Peelability]
The appearance of the retardation film peeled off from the first and second rolls is inspected, and ○ (good) when no streaks appear on the appearance, and x (bad) when streaks appear on the appearance ).

[Thickness variation]
As a result of measuring the film thickness of the obtained retardation film (100 m) and calculating the fluctuation amount with the standard deviation, ○ (good) when the film thickness fluctuation is less than 1%, x (bad) when it is 1% or more ).

[Comprehensive evaluation]
The case where all of the evaluation items of pressure fluctuation, molding speed, peelability, and film thickness fluctuation were satisfied was evaluated as ○ (good), and the case where any one of the evaluation items was not satisfied was evaluated as x (defective). The results are shown in Table 1.

  As shown in Table 1, in Example 1 provided with an air knife and a control plate, the pressure fluctuation in the air gap is small, and even when manufactured at a molding speed that satisfies the productivity, the film thickness fluctuation is less than 1%, and There was no problem in peelability. Further, in Example 2 where the air knife wind speed was increased from Example 1, the film thickness variation was 1%. Therefore, according to the manufacturing method according to the example, the molding speed was increased to improve productivity. I can also expect that.

  In addition, since the retardation films according to Example 1 and Example 2 have small variations in thickness, the image is distorted when the transmitted light is observed from the front direction or the oblique direction using a polarizing plate. can not see. Therefore, it is possible to provide an optical retardation film having high productivity and stable quality without deteriorating the image quality of the liquid crystal display device.

  On the other hand, in Comparative Example 1, there was no problem with the pressure fluctuation and the accompanying film thickness fluctuation of the retardation film, and the peelability was good, but the molding speed satisfying the productivity was not satisfied. In Comparative Example 2, when the molding speed was increased to satisfy the productivity, the cooling by the first roll became insufficient, the peelability was inferior, and the appearance of the retardation film was poor. In Comparative Example 3, the releasability was improved by providing the air knife, but since the control plate was not provided, the pressure fluctuation in the air gap was large, and the film thickness fluctuation of the retardation film was also large.

DESCRIPTION OF SYMBOLS 1 Film manufacturing apparatus, 2 dies, 3 1st roll, 4 2nd roll, 5 ventilation member, 6 control board, 10 resin composition, 11 resin film

Claims (6)

A die for extruding the molten resin composition;
A first roll and a second roll disposed below the discharge port of the die and sandwiching the resin composition extruded from the discharge port;
A blowing member for injecting air to the first roll;
Provided on the flow path of the air jetted from the blowing member, and having a control plate for controlling the air flow,
A resin film that prevents the air from flowing from the discharge port to the air gap between the first roll and the second roll by the control plate while jetting air to the first roll. Production method.   The air blowing member is provided on the side of the first roll opposite to the side on which the die is provided, and the air flows on a side opposite to the side of the first roll facing the second roll. 1. A method for producing a resin film according to 1.   The said control board is a manufacturing method of the resin film of Claim 1 or 2 arrange | positioned through the said ventilation member and the said 1st roll.   The said control board of the resin film of Claim 1 or 2 provided in the position offset on the opposite side to the said 2nd roll from the position which opposed the said ventilation member through the said 1st roll. Production method.   The method for producing a resin film according to claim 1, wherein the first roll is a nip roll. A die for extruding the molten resin composition;
A first roll and a second roll disposed below the discharge port of the die and sandwiching the resin composition extruded from the discharge port;
A blowing member for injecting air to the first roll;
Provided on the flow path of the air jetted from the blowing member, and having a control plate for controlling the air flow,
An apparatus for producing a resin film, which prevents inflow of the air between the discharge port, the first roll, and the second roll by the control plate while jetting air to the first roll.

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