JP5419642B2 - Method and apparatus for producing coated film - Google Patents

Description

  The present invention is a method and apparatus for producing a coated film, and in particular, a coating liquid containing a low molecular weight compound is applied on a traveling film, and the coating liquid is applied to the low molecular weight in a heating and drying zone provided with a transport roller. It is related with the manufacturing method and apparatus of a coating film which manufactures a coating film by sending the airflow more than melting | fusing point of a compound and heat-drying.

  Coating films such as gas barrier films, protective films, optical compensation films, and antireflection films are used in various devices such as optical devices, display devices such as liquid crystal displays and organic EL displays, semiconductor devices, and thin film solar cells.

  By the way, when the coating film of the coating film is an optical compensation film, an antireflection film, or the like, the coating liquid contains a low molecular weight compound (for example, an ultraviolet polymerization initiator), and the coating film is heated and dried. In addition, the low molecular weight substance volatilizes and adheres to the transport roller in the heating and drying zone to form dew and adhere to the film, resulting in a problem that an optical film cannot be produced with high yield. In addition, since the low molecular weight substance adheres to the conveyance roller in the heating and drying zone, it is necessary to clean the conveyance roller, and there is a problem that the operation rate of the coating film manufacturing apparatus decreases. In addition, the low molecular weight substance mentioned here refers to a substance having a molecular weight of generally 1000 or less.

  Regarding this problem, although the film produced by the solution casting method is dried, Patent Document 1 discloses that the film is dried in order to prevent film contamination due to condensation condensation of low molecular weight substances volatilized in the heat drying zone. It is described that the temperature of the portion in contact with the wind (excluding the floor surface) is higher by 5 ° C. or more than the saturation temperature of the low molecular weight substance.

  Further, in Patent Document 2, in a method for producing an optical film in which a coating layer is dried with heated air in a drying zone and then the coating layer is cured in a curing zone, a partition is provided between the drying zone and the curing zone. An intermediate zone is provided, and dew condensation of low molecular weight compounds is prevented by controlling the temperature of the intermediate zone to be lower than both the temperature of the drying zone and the temperature of the curing zone.

JP 2001-198934 A JP 2009-205092 A

  However, when the coating liquid is dried in the heating and drying zone provided with the conveying roller, the methods of the cited references 1 and 2 show that the low molecular weight compound is condensed on the conveying roller at the film inlet or the film outlet in the heating and drying zone. It turns out that there is a problem that cannot be prevented. In addition, the atmospheric temperature distribution in the heating and drying zone becomes unstable due to the influence of the volatilized solvent gas, and the drying speed of the coating film changes, which causes drying unevenness.

  The present invention has been made in view of such circumstances, and it is possible to prevent condensation of a low molecular weight compound on the transport roller at the film entrance or film exit of the heat drying zone, and the atmospheric temperature distribution in the heat drying zone. An object of the present invention is to provide a method and an apparatus for producing a coated film that can easily perform the control.

In order to achieve the above object, a method for producing a coated film according to the present invention comprises applying a coating solution containing a solvent and a low molecular weight compound on a traveling film, and heating the coating solution with a transport roller. In the method for producing a coated film by feeding an airflow having a melting point of the low molecular weight compound or higher and drying by heating, the film lower side of the traveling film at the film inlet or the film outlet of the heat drying zone to, by disposing the ground level direction substantially parallel to the plate member of the heating drying zone, condensation in conveying roller solvent gas atmosphere cools volatilized from the coating cloth layer is retained to the position of the transport roller This is characterized by preventing the occurrence of. The apparatus for producing a coated film of the present invention includes a coating apparatus that applies a coating liquid containing a solvent and a low molecular weight compound on a traveling film, and heats the coating liquid by sending an airflow that is equal to or higher than the melting point of the low molecular weight compound. A coating film manufacturing apparatus provided with a conveying roller for drying, wherein the heating drying unit is a film inlet or a film outlet of the heating drying apparatus, and the heating drying unit is provided below the traveling film. A plate member substantially parallel to the ground level of the apparatus is provided.

  In the present invention, at the film entrance or film exit of the heat drying zone, a plate member is disposed on the lower side of the traveling film in a direction substantially parallel to the ground level of the heat drying zone. This plate member temporarily suppresses the solvent gas atmosphere that has been volatilized and cooled from the coating film from falling to the bottom of the heat drying zone according to gravity. And in this invention, since the airflow more than melting | fusing point of the low molecular weight compound contained in a coating liquid is sent in the heat drying zone, the temperature reduction of a conveyance roller can be prevented with the temperature of the airflow by the board member, and it volatilized. It is possible to prevent the low molecular weight compound from condensing on the conveying roller.

  In other words, by providing a plate member, it is possible to prevent condensation of low molecular weight compounds on the transport roller at the film entrance or film exit in the heating and drying zone, so it is possible to eliminate the smearing failure on the coating film. This eliminates the need for cleaning, thereby increasing the operating rate of the manufacturing apparatus. In addition, since the control of the atmospheric temperature distribution in the heating and drying zone can be easily performed, measures against drying unevenness and drying speed control can be easily performed.

  According to the invention, it is possible to prevent the low molecular weight compound from condensing on the transport roller at the film inlet or the film outlet of the heat drying zone, and the atmospheric temperature distribution in the heat drying zone can be easily controlled.

In order to achieve the above object, a method for producing a coated film according to the present invention comprises applying a coating solution containing a solvent and a low molecular weight compound on a traveling film, and heating the coating solution with a transport roller. In the method for producing a coated film by sending an air flow having a melting point of the low molecular weight compound or more and drying by heating, the heating and drying zone has a heating and drying zone below the traveling film. by disposing the ground level substantially perpendicular to the plate member, the solvent gas atmosphere cools volatilized from the coating cloth film to dwell position of the conveying roller condensation in conveying roller so as not to occur It is characterized by that. The apparatus for producing a coated film of the present invention includes a coating apparatus that applies a coating liquid containing a solvent and a low molecular weight compound on a traveling film, and heats the coating liquid by sending an airflow that is equal to or higher than the melting point of the low molecular weight compound. A coating film manufacturing apparatus including a conveying roller for drying, and a plate that is substantially perpendicular to a ground level on the lower side of the traveling film in the heating and drying apparatus. A member is provided.

  In the present invention, in the heat drying zone, a plate member is disposed on the lower side of the traveling film in a direction substantially perpendicular to the ground level of the heat drying zone. By this plate member, the amount of the solvent gas atmosphere that has been volatilized and cooled from the coating film falls to the bottom of the heat drying zone according to gravity is suppressed. That is, since the plate member arranged in the substantially vertical direction makes it easy for the solvent gas to accumulate up to the position of the transport roller, the temperature of the transport roller becomes higher than the temperature around the transport roller, and condensation of low molecular weight compounds on the transport roller. Dirt can be prevented.

  Therefore, according to the present invention, it is possible to prevent the low molecular weight compound from condensing on the transport roller at the film entrance or film exit of the heat drying zone, and to easily control the atmospheric temperature distribution in the heat drying zone. Can do.

  In this invention, it is preferable that the conveyance angle of the film in the said heat drying zone is 30 degrees or less, or the said heat drying apparatus is provided at an angle of 30 degrees or less. In addition, although it is preferable that it is 30 degrees or less, More preferably, it is 20 degrees or less, More preferably, it is 12 degrees or less.

  In addition, the functional film manufactured by the manufacturing method or apparatus of the present invention does not cause dew stains on the coating film of the low molecular weight compound on the conveying roller to cause failure or drying unevenness. It can be suitably used as various functional films such as display devices, semiconductor devices, and thin film solar cells.

  According to the present invention, it is possible to prevent the low molecular weight compound from condensing on the transport roller at the film inlet or the film outlet in the heat drying zone, and it is possible to easily control the atmospheric temperature distribution in the heat drying zone. .

It is the schematic which shows the manufacturing process of the optical film to which this invention is applied. It is the schematic which shows the drying apparatus which concerns on this invention. It is the schematic which shows the drying apparatus which concerns on this invention. It is the schematic which shows the drying apparatus which concerns on this invention. It is a graph which shows the measurement result of an Example.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for manufacturing a coated film and a manufacturing apparatus of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an example of a manufacturing process of a coated film, and shows a manufacturing process 10 of an optical compensation film. In addition, the arrangement | positioning form of the conveyance roller in the manufacturing process 10 of an optical compensation film shall not be limited to the aspect of FIG.

  As shown in FIG. 1, the optical compensation film manufacturing process 10 mainly includes an alignment film forming process 12, a rubbing process 14 for performing a rubbing process on the alignment film, and a liquid crystal layer forming process 16 after the rubbing process. And.

  The long transparent film 24a sent out from the long roll (film roll) 20 of the polymer film by the delivery machine 22 is conveyed by the conveyance roller 26 and removed by the surface dust remover 28, and then the alignment film forming step 12 is performed. Sent to.

  In the alignment film forming step 12, a coating liquid containing an alignment film forming resin is applied by a coating machine 30, and dried by a drying device 32, whereby a resin layer is formed on the surface of the transparent film 24a. Then, the transparent film 24a is further sent to the rubbing treatment step 14. In addition, you may wind up the film obtained here once.

  In the rubbing treatment step 14, a rubbing device comprising a rubbing roller 34, a guide roller 36 fixed to a roller stage with a spring, and a dust remover 37 provided to the rubbing roller is used to rub the transparent film 24b having an alignment film forming resin layer. Processing is performed. Thereby, the surface of the formed alignment film is dust-removed by the surface dust remover 38 provided adjacent to the rubbing device. A known device other than the above may be used as the rubbing device. After the dust is removed, the transparent film 24 c on which the alignment film is formed is transported by the transport roller 40 and further sent to the liquid crystal layer forming step 16.

  In the liquid crystal layer forming step 16, a coating liquid containing a liquid crystalline discotic compound is applied onto the alignment film of the transparent film 24c by the coating machine 42, and after the solvent is evaporated, the coating layer is formed in the drying device 44. It is heated to the discotic nematic phase formation temperature (here, the residual solvent in the coating layer also evaporates). Thereby, a liquid crystal layer having a discotic nematic phase is formed.

  The liquid crystal layer is then irradiated with ultraviolet rays from an ultraviolet (UV) lamp 46, and the liquid crystal layer is crosslinked. In order to crosslink the liquid crystal layer, it is necessary to use a liquid crystal discotic compound having a crosslinkable functional group as the liquid crystal discotic compound.

  The applicator 42 and the heat drying device 44 are generally installed in a clean room in order to perform precise application and drying. The clean room always maintains a clean and pressurized state by, for example, downflowing clean air-conditioned air from the ceiling surface.

  The coating machine 42 may be an extrusion type, a roll coater type, a gravure coater type, a slide coat type, or other coating methods. The drying apparatus of the present invention can be applied not only to an organic solvent-based coating solution but also to an aqueous system, but exhibits an effect in an organic solvent-based coating solution in which drying unevenness easily occurs.

  Examples of the solvent contained in the coating solution include methyl ethyl ketone (MEK), water ethanol, 1-methoxy-2-propanol acetate (MMPG-AC), N-methylpyrrolidone (NMP), normal propyl alcohol (n-PrOH), A composition comprising methyl isobutyl ketone (MIBK) and anone is used.

  As the low molecular weight compound contained in the coating solution, a polymerization initiator is used as a hardener. Examples of the polymerization initiator include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides (described in JP-A-2001-139663, etc.), 2, Examples include 3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, onium salts, borate salts, and active halogen compounds.

  “Latest UV Curing Technology” {Publisher: Kazuhiro Takasato, Publisher; Technical Information Association, 1991}, p. 159, and "Ultraviolet curing system" (by Kiyomi Kato, published by the General Technology Center in 1989), p. Various examples are also described in 65-148 and are useful in the present invention.

  Preferable examples of commercially available photocleavable photoradical polymerization initiators include “Irgacure (184, 651, 907)” manufactured by Ciba Japan Co., Ltd.

  As an application condition for applying the application liquid to the film 24c, for example, the wet application amount is set to about 5 to 15 μm. The film thus coated with the coating liquid is run to the drying device 44, and finally the film thickness of the coating film surface becomes about 1 to 5 μm in the dry film state.

  The drying device 44 is disposed on the downstream side of the coating machine 42 with respect to the traveling direction of the polymer film 24c, and sends an air current to the polymer film 24c to dry the coating film surface. The drying device 44 and the coating machine 42 are about 1000 mm in order to prevent the heat at the time of drying from adversely affecting the coating machine 42 and because the hot air is not immediately applied to the coating film surface of the polymer film 24c. It is preferable to install with an interval of.

  FIG. 2 shows the heat drying apparatus 44.

  FIG. 2A shows a conventional heat drying apparatus 44. The heating and drying device 44 mainly includes a drying box 44a, a two-dimensional nozzle 60 for supplying hot air drying air, and a plurality of heatable transport rollers 62, 62. The drying box 44a is provided with a film inlet 64 and a film outlet 66 for the polymer film 24c to travel.

  In the heating and drying apparatus 44 of FIG. 2A, there is a problem that the low molecular weight compound evaporated from the coating film is condensed on the transport roller 62 at the film inlet 64 or the film outlet 66. In addition, the atmospheric temperature distribution in the heating / drying apparatus becomes unstable due to the influence of the volatilized solvent gas, and the drying speed of the coating film changes, which causes drying unevenness.

  Therefore, by configuring the heating and drying apparatus as at least one of FIGS. 2B and 2C, the problem of the low molecular weight compound condensing on the conveyance roller and the problem of uneven drying of the coating film are solved. I found that I can do it.

  The heating / drying apparatus 44 shown in FIG. 2 (B) feeds the coating liquid for the polymer film 24c from the two-dimensional nozzle 60 with an air flow that is equal to or higher than the melting point of the low molecular weight compound and heats and dries it. A plate member 68 that is substantially parallel to the ground level of the heating / drying apparatus is disposed below the polymer film 24c that the film inlet 64 travels.

  The plate member 68 temporarily suppresses the solvent gas atmosphere that has been volatilized and cooled from the coating film from dropping to the bottom of the heating and drying apparatus according to gravity. In the heat drying apparatus, since an air flow higher than the melting point of the low molecular weight compound contained in the coating liquid is sent, the plate member 68 can prevent the temperature drop of the transport roller 62 at the film inlet 64 due to the temperature of the air flow. Therefore, it is possible to prevent the volatilized low molecular weight compound from condensing on the transport roller 62 at the film entrance 64. In other words, by providing a plate member, it is possible to prevent condensation contamination of the low molecular weight compound on the transport roller at the film entrance of the heating and drying apparatus, so that it is possible to eliminate the smearing failure on the coating film, and the transport roller can be cleaned. By eliminating the necessity, the operating rate of the manufacturing apparatus can be increased.

  Moreover, the control of the atmospheric temperature distribution in the heat drying apparatus can be easily performed by the heat drying apparatus of FIG. This is because the ambient temperature in the vicinity of the transport roller 62 can be determined by the air flowing from the film inlet 64. Therefore, dry unevenness countermeasures and drying speed control can be easily performed.

  The plate member 68 preferably has a length on the lower side of the transport roller 62 at the film inlet 64.

  The heating / drying device 44 shown in FIG. 2 (C) feeds the coating liquid for the polymer film 24c from the two-dimensional nozzle 60 with an air flow higher than the melting point of the low molecular weight compound, similarly to the heating / drying device shown in FIG. 2 (B). Heat to dry. A plate member 70 that is substantially perpendicular to the ground level is disposed below the traveling polymer film 24c.

  The plate member 70 suppresses the amount of the solvent gas atmosphere that volatilizes and cools from the coating film and falls to the bottom of the heating and drying apparatus according to gravity. That is, since the plate member 70 disposed in the substantially vertical direction makes it easy for the solvent gas to accumulate up to the position of the transport roller 62 at the film inlet 64, the temperature of the transport roller 62 becomes higher than the temperature around the transport roller, It is possible to prevent condensation of low molecular weight compounds on the roller.

  Moreover, the control of the atmospheric temperature distribution in the heating and drying apparatus can be easily performed by the heating and drying apparatus in FIG. This is because the air flowing from the film inlet 64 can be buffered under the film by the plate member 70, so that the ambient temperature under the film can be determined. Therefore, dry unevenness countermeasures and drying speed control can be easily performed.

  The plate member 70 is preferably provided on the downstream side of the transport roller 62 at the film inlet 64.

  2B and 2C, the conveyance roller 62 at the film inlet 64 has been described, but the same effect can be achieved with the conveyance roller 62 at the film outlet 66. Therefore, according to the present invention, it is possible to prevent the low molecular weight compound from condensing on the transport roller at the film entrance or film exit of the heat drying zone, and to easily control the atmospheric temperature distribution in the heat drying zone. Can do.

  And as shown in FIG. 3, it is preferable that the heat drying apparatus 44 is provided with the angle (theta) of 30 degrees or less with respect to the ground level GL. In addition, although it is preferable that it is 30 degrees or less, More preferably, it is 20 degrees or less, More preferably, it is 15 degrees or less, More preferably, it is 12 degrees or less.

  In the said embodiment, although the manufacturing process 10 of the optical compensation film was demonstrated to the example, it is not limited to this, Other functional films, for example, an antireflection film, the thin film form of the optical use used for various image display apparatuses It can be applied to film production and transport processes.

  2 (B) and 2 (C) have described at least one of the cases of the present invention. For example, as shown in FIG. 4, the plate member 68 in FIG. 2 (B) and FIG. 2 (C). It is also effective to arrange the plate member 70 together.

[the film]
The film used in the present invention is generally polyethylene terephthalate having a width of 0.3 to 5 m, a length of 45 to 10,000 m, and a thickness of 5 to 200 μm, polyethylene-2,6 naphthalate, cellulose diacetate, cellulose triacetate, cellulose acetate pro Coated or laminated α-polyolefins having 2 to 10 carbon atoms such as plastic film such as pionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide, polyamide, paper, polyethylene, polypropylene, ethylene butene copolymer, etc. Paper, metal foils such as aluminum, copper, and tin, or those obtained by forming a preliminary processing layer on the surface of a belt-like substrate are included.

[Coating solution]
In the present invention, a coating liquid containing a solvent and a low molecular weight compound such as a plasticizer or a hardener is applied to the surface of the coating film, dried, and then cut into a desired length and width. The typical examples include an optical compensation film and an antireflection film.

  The experiment was performed in the manufacturing process 10 of the coated film shown in FIG.

As the film 24a, triacetyl cellulose (Fujitack, manufactured by Fuji Film Co., Ltd.) having a thickness of 80 μm was used. Then, the surface of the film, the long-chain alkyl-modified Poval (MP-203, manufactured by Kuraray Co., Ltd.) After 2 wt% solution of the film 1 m ² per 25ml applying the alignment film formed by drying for 1 minute at 60 ° C While the film 24b on which the resin layer was formed was conveyed at 30 m / min, the alignment layer was formed by rubbing the surface of the alignment layer resin layer.

And, on the alignment film obtained by rubbing the alignment film resin layer, the coating liquid is 4: 1 by weight ratio of (3) of the discotic compound TE-8 and (5) of TE-8. A coating liquid containing a liquid crystalline compound to be a 40 wt% methyl ethyl ketone solution of a mixture obtained by adding 1 wt% of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Japan Co., Ltd.) to the mixture was used. While running the film 24c at 30 m / min, this coating solution was applied onto the alignment film with a gravure coating device so that the amount of the coating solution was 5 to 7 mL per 1 m ^{2 of the} strip-shaped base film. And after application | coating, it was dried with the heat drying apparatus 44 adjusted to 135 degreeC. The heating and drying device 44 is provided with six transport rollers 62, 62..., And the temperature of the transport rollers is 25.4 ° C., 26.5 ° C., 38.6 ° C., 46.9 ° C. The temperature was set to 53.3 ° C and 63.6 ° C.

  Here, the atmospheric temperature distribution in the heating and drying apparatus was examined using the conventional heating and drying apparatus in FIG. 2A and the heating and drying apparatus in which the plate members 68 and 70 in FIG. 4 were disposed. The temperature was measured near the bottom (floor) and near the film (base).

  Thereafter, the film 24c was irradiated with ultraviolet rays by an ultraviolet lamp.

  FIG. 5 is a graph showing the measurement results. FIG. 5A is a conventional heating and drying apparatus, and FIG. 5B is a heating and drying apparatus in which plate members 68 and 70 according to the present invention are arranged. .

  As can be seen from FIG. 5, according to the present invention, it is understood that the atmospheric temperature distribution control can be easily performed. And in the manufactured coating film, although the drying nonuniformity is seen in the conventional heat drying apparatus of FIG. 5 (A), the heating provided with the plate members 68 and 70 according to the present invention of FIG. 5 (B). No drying unevenness was observed in the drying apparatus. Further, condensation contamination of low molecular weight compounds on the conveyance roller at the film entrance is also observed in the conventional heating and drying apparatus of FIG. 5A, but the plate members 68 and 70 according to the present invention of FIG. It was not seen in the installed heat drying apparatus.

  Therefore, according to the present invention, it is possible to prevent the low molecular weight compound from condensing on the transport roller at the film entrance or film exit of the heat drying zone, and to easily control the atmospheric temperature distribution in the heat drying zone. You can see that

  DESCRIPTION OF SYMBOLS 10 ... Manufacturing process of optical compensation film, 24a, 24b, 24c ... (polymer) film, 30 ... coating machine, 32 ... drying apparatus, 42 ... coating machine, 44 ... drying apparatus, 44a ... drying box, 62 ... conveyance roller, 64 ... Film inlet, 66 ... Film outlet, 68, 70 ... Plate member

Claims (4)

By applying a coating liquid containing a solvent and a low molecular weight compound on a traveling film, and sending the coating liquid in a heating and drying zone equipped with a transport roller by feeding an airflow above the melting point of the low molecular weight compound, A method for producing a coated film for producing a coated film,
At the film entrance or film exit of the heating and drying zone, a solvent is volatilized and cooled from the coating film by disposing a plate member on the lower side of the traveling film in a direction substantially parallel to the ground level of the heating and drying zone. A method for producing a coated film, characterized in that a gas atmosphere is retained at the position of the transport roller so that condensation of the low molecular weight compound does not occur on the transport roller. By applying a coating liquid containing a solvent and a low molecular weight compound on a traveling film, and sending the coating liquid in a heating and drying zone equipped with a transport roller by feeding an airflow above the melting point of the low molecular weight compound, A method for producing a coated film for producing a coated film,
In the heat drying zone, a plate member is disposed on the lower side of the traveling film in a direction substantially perpendicular to the ground level of the heat drying zone, so that the solvent gas atmosphere volatilized and cooled from the coating film is transferred to the transport roller. The method for producing a coated film is characterized in that the low-molecular weight compound is prevented from condensing on the conveying roller by staying at the position. A coating apparatus for applying a coating liquid containing a solvent and a low molecular weight compound on a traveling film; and a heating / drying apparatus provided with a conveying roller for heating and drying the coating liquid by sending an airflow higher than the melting point of the low molecular weight compound; An apparatus for producing a coated film comprising:
At the film inlet or film outlet of the heating and drying apparatus, a solvent gas atmosphere that has evaporated and cooled from the coating film is retained at the position of the transport roller on the lower side of the traveling film, and the low molecular weight is stored in the transport roller. An apparatus for producing a coated film, comprising a plate member disposed in a direction substantially parallel to the ground level of the heating and drying apparatus so as not to cause condensation of the compound . A coating apparatus for applying a coating liquid containing a solvent and a low molecular weight compound on a traveling film; and a heating / drying apparatus provided with a conveying roller for heating and drying the coating liquid by sending an airflow higher than the melting point of the low molecular weight compound; An apparatus for producing a coated film comprising:
In the heating and drying apparatus, a solvent gas atmosphere that has been volatilized and cooled from the coating film stays at the position of the transport roller on the lower side of the traveling film, and condensation of the low molecular weight compound occurs on the transport roller. An apparatus for producing a coated film, characterized in that a plate member substantially perpendicular to the ground level is disposed.

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