JP2017003186A - Paint film dryer, paint film dry method, and manufacturing method of liquid crystal sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paint film dryer which effectively prevents dry unevenness of a paint film without deteriorating the production efficiency, and to provide a paint film dry method and a manufacturing method of a liquid crystal sheet.SOLUTION: A paint film dryer 10 includes an air supply part 11 and an exhaust part 12 which are disposed facing each other. The air supply part 11 and the exhaust part 12 form airflow flowing along a surface of a paint film 21. Intensity of turbulence of the airflow is 2% or lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coating film drying apparatus and a coating film drying method. The present invention also relates to a method for producing a liquid crystal sheet.

  In general, it is known that, in the process of applying liquid crystal to the surface of a base material, liquid crystal drying unevenness occurs due to the influence of a slight amount of wind and the product quality deteriorates.

  In Patent Document 1, in order to reduce drying unevenness, the relative speed of the airflow on the coating film with respect to the base material is set to ± 0.1 m / s or less, that is, the gas layer on the coating film is almost equal to the base material. It has been proposed to stay stationary. However, in this method, since the flow velocity of the airflow on the coating film is extremely low, there is a problem that the time until the drying is completed is prolonged and the production efficiency is greatly reduced.

  In Patent Document 1, in addition to the above method, it is also proposed to promote drying by direct heat transfer using a heating roll or the like. However, there is a possibility that convection of the coating film may occur due to heat transfer. It is necessary to add a convection inhibitor to the material, which greatly restricts the coating conditions and the ink material.

JP-A-9-73016

  The present invention has been made in consideration of such points. An object of the present invention is to provide a coating film drying apparatus, a coating film drying method, and a liquid crystal sheet manufacturing method capable of effectively preventing drying unevenness of the coating film without reducing the production efficiency.

The coating film drying apparatus according to the present invention comprises:
An air supply portion and an exhaust portion arranged to face each other;
The air supply part and the exhaust part form an airflow flowing along the surface of the coating film,
The turbulent intensity of the airflow is 2% or less.

In the coating film drying apparatus according to the present invention,
The airflow turbulence intensity may be 1% or less.

In the coating film drying apparatus according to the present invention,
The air supply part and the exhaust part are arranged facing each other along the traveling direction of the base material,
The direction of the airflow may be the same as or opposite to the traveling direction of the substrate.

In the coating film drying apparatus according to the present invention,
A plurality of sets of the air supply unit and the exhaust unit may be arranged along the traveling direction of the base material.

In the coating film drying apparatus according to the present invention,
The air supply unit has a plurality of rectifying passages bundled together,
The diameter d [mm] of each rectifying passage, the axial length L [mm], and the wind velocity u [m / s] of the airflow may satisfy the relational expression L / d ² ≧ 1950 × u.

In the coating film drying apparatus according to the present invention,
The air supply unit has a plurality of rectifying passages bundled together,
The diameter d [mm] and the axial length L [mm] of each rectifying passage may satisfy a relational expression of L / d ² ≦ 24000.

The coating film drying method according to the present invention comprises:
Forming an airflow that flows along the surface of the coating,
The turbulence intensity of the airflow is set to 2% or less.

In the coating film drying method according to the present invention,
The turbulent intensity of the airflow may be 1% or less.

In the coating film drying method according to the present invention,
The direction of the airflow may be the same as or opposite to the traveling direction of the substrate.

In the coating film drying method according to the present invention,
The air flow may be formed at a plurality of locations along the traveling direction of the substrate.

In the coating film drying method according to the present invention,
Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
The diameter d [mm] of each rectifying passage, the axial length L [mm], and the wind velocity u [m / s] of the airflow may satisfy the relational expression L / d ² ≧ 1950 × u.

In the coating film drying method according to the present invention,
Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
The diameter d [mm] and the axial length L [mm] of each rectifying passage may satisfy a relational expression of L / d ² ≦ 24000.

The method for producing a liquid crystal sheet according to the present invention comprises:
Applying liquid crystal to the surface of the substrate;
A step of drying the applied liquid crystal coating film;
With
In the drying step, an airflow flowing along the surface of the coating film is formed,
The turbulence intensity of the airflow is set to 2% or less.

In the method for producing a liquid crystal sheet according to the present invention,
The turbulent intensity of the airflow may be 1% or less.

In the method for producing a liquid crystal sheet according to the present invention,
The direction of the airflow may be the same as or opposite to the traveling direction of the base material.

In the method for producing a liquid crystal sheet according to the present invention,
The airflow may be formed at a plurality of locations along the traveling direction of the base material.

In the method for producing a liquid crystal sheet according to the present invention,
Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
The diameter d [mm] of each rectifying passage, the axial length L [mm], and the wind velocity u [m / s] of the airflow may satisfy the relational expression L / d ² ≧ 1950 × u.

In the method for producing a liquid crystal sheet according to the present invention,
Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
The diameter d [mm] and the axial length L [mm] of each rectifying passage may satisfy a relational expression of L / d ² ≦ 24000.

  According to the present invention, it is possible to effectively prevent uneven coating from drying without reducing production efficiency.

FIG. 1 is a schematic view showing an apparatus for producing a liquid crystal sheet provided with a coating film drying apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged schematic view showing one of a set of an air supply unit and an exhaust unit in the coating film drying apparatus of FIG. FIG. 3 is an enlarged perspective view showing a plurality of rectifying passages included in the air supply unit of FIG.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that, in the drawings attached to the present specification, for the sake of easy understanding of the drawings, the scale and the vertical / horizontal dimension ratio are appropriately changed and exaggerated from those of the actual ones.

  FIG. 1 is a schematic view showing a liquid crystal sheet manufacturing apparatus provided with a coating film drying apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the liquid crystal sheet manufacturing apparatus 1 of the present embodiment includes first to third guide rollers 4 to 6 that guide a sheet-like base material 20 that is conveyed by a roll-to-roll method. A coating device 2 that applies liquid crystal to the surface of the substrate 20 being transported, a coating film drying device 10 that dries the coating film of the applied liquid crystal, a coating film curing device 3 that cures the dried coating film, It has.

  Among these, the coating device 2, the coating film drying device 10, and the coating film curing device 3 are arranged in this order along the conveyance direction of the base material 20. In the illustrated example, the coating device 2 is disposed on the first guide roller 4, and the coating film drying device 10 is disposed between the first guide roller 4 and the second guide roller 5. The film curing device 3 is disposed on the third guide roller 6.

  The coating apparatus 2 is, for example, a bar coater type coating apparatus, and applies a liquid coating material (hereinafter also referred to as ink) to the surface of the substrate 20 with a uniform film thickness on the first guide roller 4. It has become. The coating method of the coating apparatus 2 is not limited to the bar coater method, and other coating methods such as a gravure coater, a knife coater, a curtain coater, and a die coater can also be used. In the present embodiment, an ultraviolet curing reaction initiator is added to the ink applied by the coating apparatus 2, and an ultraviolet irradiation apparatus that irradiates ultraviolet rays is used as the coating film curing apparatus 3.

  As shown in FIG. 1, the coating film drying apparatus 10 according to the present embodiment includes a chamber 16 through which a base material 20 passes, and an air supply unit 11 and an exhaust unit 12 that are disposed facing each other in the chamber 16. ,have. In the present embodiment, a plurality of sets (four sets in the illustrated example) of the air supply unit 11 and the exhaust unit 12 are arranged along the traveling direction of the base material 20, but the present invention is not limited to this. Instead, only one set of the air supply unit 11 and the exhaust unit 12 may be arranged.

  FIG. 2 is an enlarged schematic view showing one of the set of the air supply unit 11 and the exhaust unit 12.

  As shown in FIG. 2, the air supply unit 11 and the exhaust unit 12 are positioned close to the coating film 21 side of the substrate 20 while facing each other. An interval B between the lower end portion of the air supply unit 11 and the surface of the substrate 20 is, for example, 50 mm.

  As shown in FIG. 2, one end of an air supply pipe 13a is connected to the side of the air supply section 11 opposite to the exhaust section 12 side, and the other end of the air supply pipe 13a is connected to an air supply section. A blower 14a (for example, a blower fan) is provided. The air supply fan 14a introduces gas into the air supply pipe 13a. The gas introduced into the air supply pipe 13a passes through the air supply pipe 13a and is then sent out from the air supply section 11 to the exhaust section 12 side.

  On the other hand, one end of an exhaust pipe 13b is connected to the side of the exhaust part 12 opposite to the air supply part 11 side, and an exhaust fan 14b (for example, an air blower) is connected to the other end of the exhaust pipe 13b. Fan) is provided. The exhaust fan 14b exhausts the gas in the exhaust pipe 13b to the outside. When the gas in the exhaust pipe 13b is discharged to the outside by the exhaust fan 14b, the pressure in the exhaust pipe 13b is reduced, and due to the pressure difference, the exhaust pipe 13b passes through the exhaust part 12 from the air supply part 11 side. Gas is sucked in.

  Gas is sent from the air supply unit 11 to the exhaust unit 12 side, and gas is sucked into the exhaust unit 12 from the air supply unit 11 side, so that a coating film is formed between the air supply unit 11 and the exhaust unit 12. An airflow flowing along the surface of 21 can be formed. The solvent vapor evaporated from the coating film 21 is pushed away from above the coating film 21 by the air flow, whereby the drying of the coating film 21 is promoted. As long as the turbulence intensity described later can be maintained low, the larger the airflow velocity, the shorter the drying time of the coating film 21, and the more preferable is the average wind speed of 0.5 m / s or more, more preferably the average wind speed of 1 m / s. More preferably, the average wind speed is 2 m / s or more.

  In the present embodiment, the turbulence intensity of the airflow flowing along the surface of the coating film 21 is set to 2% or less, more preferably 1% or less. Thereby, the nonuniformity of the transport of the solvent vapor evaporated from the coating film 21 can be reduced, and it can be effectively prevented that the nonuniformity of drying occurs in the coating film. The “turbulence intensity” means the ratio of the standard deviation of the wind speed to the average wind speed, and is defined by JIS C1400-1: 2010. The strength of the turbulent flow that flows along the surface of the coating film 21 is, for example, an intermediate position between the air supply unit 11 and the exhaust unit 12 and a measurement position that is C = 25 mm away from the surface of the coating film 21 (in FIG. 2). At the position indicated by the symbol P, measurement can be performed using a laser Doppler velocimeter (for example, FLV system 8835 manufactured by Kanomax Co., Ltd.).

  FIG. 3 is an enlarged perspective view showing a part of the air supply unit 11. As shown in FIG. 3, the air supply unit 11 has a plurality of rectifying passages 15 bundled in parallel with each other. In the illustrated example, each rectifying passage 15 has a hexagonal cross section and is disposed adjacent to each other. The cross-sectional shape of each rectifying passage 15 is not limited to a hexagonal shape, and may be a circular shape, a triangular shape, or a quadrangular shape. The gas flowing in the air supply pipe 13a passes through each rectifying passage 15 before being sent out from the air supply part 11 to the exhaust part 12 side. At this time, the flow direction of the gas is regulated by the wall of the rectifying passage 15 and aligned in parallel directions along the axial direction of the rectifying passage 15. Thereby, the turbulent intensity | strength of the airflow which flows along the surface of the coating film 21 can be reduced effectively.

The diameter d [mm] of each rectifying passage 15, the axial length L [mm], and the wind velocity u [m / s] of the airflow flowing along the surface of the coating film 21 are L / d ² ≧ 1950 × u. It is preferable to satisfy the relational expression, and it is more preferable to satisfy the relational expression of L / d ² ≧ 4300 × u. When the inventor actually verified using fluid simulation, when L / d ² <4300 × u, rectification is insufficient to reduce the turbulence intensity to 1%, and when L / d ² <1950 × u, Rectification is insufficient to reduce the turbulence intensity to 2%.

Moreover, it is preferable that the diameter d [mm] of each rectification passage 15 and the axial length L [mm] satisfy the relational expression of L / d ² ≦ 24000. When L / d ² > 24000, the pressure loss in the rectifying passage 15 is high, which is not preferable in terms of device design.

  Although not necessarily essential, it is preferable that the exhaust part 12 also has a plurality of rectifying passages 15 bundled in parallel with each other, like the air supply part 11. In this case, the gas sucked into the exhaust pipe 13b from the exhaust part 12 passes through each rectifying passage 15 so that the flow direction is regulated by the wall of the rectifying passage 15 and the axial direction of the rectifying passage 15 Are aligned in parallel with each other. Thereby, the turbulent intensity | strength of the airflow which flows along the surface of the coating film 21 can be reduced more effectively.

  As shown in FIG. 2, the distance A from the end of the air supply unit 11 on the exhaust unit 12 side to the end of the exhaust unit 12 on the air supply unit 11 side is preferably 150 cm or less. In this case, the solvent vapor evaporated from the coating film 21 can be efficiently exhausted from the exhaust unit 12 before being saturated on the coating film 21. In the example shown, A = 150 cm.

  In the present embodiment, as shown in FIG. 2, the air supply unit 11 and the exhaust unit 12 are arranged to face each other along the traveling direction of the base material 20. In the illustrated example, the air supply unit 11 is disposed on the upstream side in the traveling direction of the base material 20 with respect to the exhaust unit 12, and between the air supply unit 11 and the exhaust unit 12, An airflow that flows in the same direction as the traveling direction is formed. Thereby, since the airflow formed between the air supply part 11 and the exhaust part 12 is rarely disturbed by the influence of the conveyance of the base material 20, the turbulence intensity of the airflow can be stably reduced. it can.

  The air supply unit 11 is disposed downstream of the exhaust unit 12 in the direction of travel of the base material 20, and the direction of travel of the base material 20 is between the air supply unit 11 and the exhaust unit 12. An airflow flowing in the opposite direction may be formed. Also in this case, since the airflow formed between the air supply unit 11 and the exhaust unit 12 is less likely to be disturbed by the influence of the transport of the base material 20, the turbulent strength of the airflow can be stably reduced. Can do.

  Next, the operation of the present embodiment having such a configuration will be described.

  As shown in FIG. 1, the sheet-like base material 20 conveyed by the roll-to-roll method is coated with ink on the surface by the coating device 2 on the first guide roller 4. Next, the base material 20 to which the ink has been applied is carried into the chamber 16 of the coating film drying apparatus 10.

  In the chamber 16, an air flow flowing along the surface of the coating film 21 is formed by the air supply unit 11 and the exhaust unit 12 arranged to face each other, and the turbulent intensity of the air flow is 2% or less, Preferably it is set to 1% or less. By the solvent vapor being pushed away from the top of the coating film 21 by the airflow flowing along the surface of the coating film 21, the drying of the coating film 21 is promoted, and the time until the drying of the coating film 21 is completed can be shortened. . Thereby, production efficiency can be improved without being restricted by the ink material. In addition, since the turbulent strength of the airflow is 2% or less, more preferably 1% or less, the transport unevenness of the solvent vapor is remarkably reduced, and the occurrence of uneven drying in the coating film 21 can be effectively prevented. .

  In the present embodiment, as shown in FIG. 1, a plurality of sets of the air supply unit 11 and the exhaust unit 12 are arranged along the traveling direction of the base material 20. Steam can be separately discharged at a plurality of locations along the traveling direction of the substrate 20. Thereby, time until drying is completed can be shortened further.

  As shown in FIG. 1, after the substrate 20 on which the coating film 21 has been dried by the airflow formed by the air supply unit 11 and the exhaust unit 12 is carried out of the chamber 16 of the coating film drying apparatus 10 to the outside. Then, it is conveyed from the second guide roller 5 to the third guide roller 6.

  On the third guide roller 6, ultraviolet rays are irradiated from the coating film curing device 3 toward the dried coating film 21 on the substrate 20, and the coating film 21 is cured.

  As described above, according to the present embodiment, in the coating film drying apparatus 10, the air current flows along the surface of the coating film 21, so that solvent vapor is washed away from the coating film 21 and drying is promoted. Therefore, the time until the drying of the coating film 21 is completed can be shortened. Thereby, production efficiency can be improved without being restricted by the ink material. Further, according to the present embodiment, the turbulent intensity of the airflow is 2% or less, more preferably 1% or less, so that the unevenness in transporting the solvent vapor is remarkably reduced, and the coating film 21 has uneven drying. It can be effectively prevented from occurring.

  Further, according to the present embodiment, the air supply unit 11 and the exhaust unit 12 are arranged to face each other along the traveling direction of the base material 20, and are in the same direction as or in the opposite direction to the traveling direction of the base material 20. Since the air flow is formed, the air flow is hardly disturbed by the influence of the progress of the base material 20, and the turbulent strength of the air flow can be stably reduced.

  Moreover, according to this Embodiment, since the group which consists of the air supply part 11 and the exhaust part 12 is arrange | positioned along the advancing direction of the base material 20, the solvent vapor | steam on the coating film 21 is a base material. It is discharged separately at a plurality of locations along the traveling direction. Thereby, time until drying is completed can be shortened further.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.

  First, as Example 1 of the present embodiment, a base material 20 having a width of 1 m, in which a liquid crystal light distribution film (polarization light distribution method) is provided as an undercoat layer on the surface of a TAC (triacetyl cellulose) film, is prepared. The said base material was conveyed to the coating device (Meyer bar type coater) 12 of the liquid crystal sheet manufacturing apparatus 1 mentioned above. In the coating apparatus 2, a liquid crystal discotic compound 19% by weight, a reaction initiator (Irgacure (registered trademark) 184) 1% by weight, MEK (methyl ethyl ketone) 20% by weight, and MIBK (methyl isobutyl ketone) are formed on the surface of the substrate 20. ) Ink mixed with 60% by weight was continuously applied with a liquid film thickness of 4 μm.

Subsequently, the base material 20 was thrown into the coating-film drying apparatus 10 immediately after application | coating, and the coating film 21 was dried. In the coating film drying apparatus 10, a plurality of rectifying passages 15 (diameter d = 5 mm, axial length L = 50 mm, L / d ² =) are bundled together while the base material 20 is conveyed at a speed of 10 m / min. 2000), the measurement position (reference symbol P in FIG. 2) is an intermediate position between the air supply unit 11 and the exhaust unit 12 and C = 25 mm away from the surface of the coating film 21. The airflow flowing along the surface of the coating film 21 was formed so that the average value of the average wind speeds at seven locations separated in the full width direction of the substrate 20 was 1 m / s. When the intensity of turbulent flow flowing along the surface of the coating film 21 was measured using a laser Doppler velocimeter (FLV system 8835 manufactured by Kanomax Co., Ltd.) at the measurement position, the maximum value at seven locations separated in the full width direction of the substrate 20. Was 2%. When the time (drying time) from when the film was dried to the coating film drying apparatus 10 until the drying of the coating film 21 was completed was measured, it was 19% of the preset standard drying time.

  Subsequently, the base material 20 from which the coating film 21 was dried was conveyed to the coating film curing device (ultraviolet irradiation device) 3. In the coating film curing device 3, the coating film 21 was cured by irradiating the surface of the substrate 20 with ultraviolet rays with an integrated light amount of 40 mJ. Then, when the surface quality of the cured coating film 21 was visually confirmed on an inspection plate through a polarizing plate, although some unevenness of light and darkness of a scale of about 5 mm to 10 mm was confirmed, it was acceptable as a product. there were.

Next, as Example 2 of the present embodiment, in the coating film drying apparatus 10, a plurality of rectifying passages 15 (diameter d = 5 mm, axial length L = 110 mm, L / d ² = 4400) bundled together. ), The average value of the average wind speeds at seven locations spaced apart in the full width direction of the substrate 20 is 1 m / s at the measurement position (the position indicated by the symbol P in FIG. 2). As described above, the liquid crystal was applied to the surface of the base material 20 in the same manner as in Example 1 except that an airflow flowing along the surface of the coating film 21 was formed. In the coating film drying apparatus 10, when the intensity of turbulent flow flowing along the surface of the coating film 21 was measured using a laser Doppler velocimeter at the measurement position, the maximum value at seven locations separated in the full width direction of the substrate 20 Was 1%. Moreover, when the drying time of the coating film 21 was measured, it was 19% of the reference | standard drying time. In addition, when the surface quality of the cured coating film 21 was visually confirmed on a viewing plate passed through a polarizing plate, no unevenness in brightness and darkness was confirmed.

Next, as Example 3 of this embodiment, in the coating film drying apparatus 10, a plurality of rectifying passages 15 (diameter d = 5 mm, axial length L = 100 mm, L / d ² = 4000) bundled with each other. ), The average value of the average wind speeds at seven locations spaced in the full width direction of the base material 20 is 2 m / s at the measurement position (the position indicated by the symbol P in FIG. 2). As described above, the liquid crystal was applied to the surface of the base material 20 in the same manner as in Example 1 except that an airflow flowing along the surface of the coating film 21 was formed. In the coating film drying apparatus 10, when the intensity of turbulent flow flowing along the surface of the coating film 21 was measured using a laser Doppler velocimeter at the measurement position, the maximum value at seven locations separated in the full width direction of the substrate 20 Was 2%. Moreover, when the drying time of the coating film 21 was measured, it was 12% of reference | standard drying time. Moreover, when the surface quality of the cured coating film 21 was visually confirmed on an inspection plate through a polarizing plate, although some unevenness of light and darkness of a scale of about 5 mm to 10 mm was confirmed, it was acceptable as a product. there were.

Next, as Example 4 of the present embodiment, in the coating film drying apparatus 10, a plurality of rectifying passages 15 (diameter d = 5 mm, axial length L = 220 mm, L / d ² = 8800) bundled with each other. ), The average value of the average wind speeds at seven locations spaced in the full width direction of the base material 20 is 2 m / s at the measurement position (the position indicated by the symbol P in FIG. 2). As described above, the liquid crystal was applied to the surface of the base material 20 in the same manner as in Example 1 except that an airflow flowing along the surface of the coating film 21 was formed. In the coating film drying apparatus 10, when the intensity of turbulent flow flowing along the surface of the coating film 21 was measured using a laser Doppler velocimeter at the measurement position, the maximum value at seven locations separated in the full width direction of the substrate 20 Was 1%. Moreover, when the drying time of the coating film 21 was measured, it was 11% of the reference | standard drying time. In addition, when the surface quality of the cured coating film 21 was visually confirmed on a viewing plate passed through a polarizing plate, no unevenness in brightness and darkness was confirmed.

  Next, as Comparative Example 1, in the coating film drying apparatus 10, using the air supply unit 11 that does not have a plurality of rectifying passages 15 bundled with each other, at the measurement position (the position indicated by the symbol P in FIG. 2). The embodiment described above, except that the airflow flowing along the surface of the coating film 21 was formed so that the average value of the average wind speed at seven locations spaced apart in the full width direction of the substrate 20 was 0.1 m / s. 1 was applied to the surface of the substrate 20 in the same manner. In the coating film drying apparatus 10, when the intensity of turbulent flow flowing along the surface of the coating film 21 was measured using a laser Doppler velocimeter at the measurement position, the maximum value at seven locations separated in the full width direction of the substrate 20 Was 5%. Moreover, when the drying time of the coating film 21 was measured, it was 100% of the standard drying time. In addition, when the surface quality of the cured coating film 21 was visually confirmed on a viewing plate passed through a polarizing plate, no unevenness in brightness and darkness was confirmed.

Next, as Comparative Example 2, the coating film drying apparatus 10 has a plurality of rectifying passages 15 (diameter d = 5 mm, axial length L = 10 mm, L / d ² = 400) bundled together. The coating film is used so that the average value of the average wind speeds at the seven positions spaced apart in the entire width direction of the base material 20 is 1 m / s at the measurement position (position indicated by the symbol P in FIG. 2) using the section 11. A liquid crystal was applied to the surface of the substrate 20 in the same manner as in Example 1 except that an airflow flowing along the surface of 21 was formed. In the coating film drying apparatus 10, when the intensity of turbulent flow flowing along the surface of the coating film 21 was measured using a laser Doppler velocimeter at the measurement position, the maximum value at seven locations separated in the full width direction of the substrate 20 Was 5%. Moreover, when the drying time of the coating film 21 was measured, it was 18% of the reference | standard drying time. Moreover, when the surface quality of the cured coating film 21 was visually confirmed on an inspection plate through a polarizing plate, unevenness in brightness and darkness was confirmed as a whole, and the product was rejected.

The apparatus conditions and evaluation results of Examples 1 to 4 and Comparative Examples 1 to 2 are summarized in Table 1 below.

  In Table 1, when the surface quality of the cured coating film 21 was visually confirmed on a viewing plate through a polarizing plate, when no unevenness in brightness and darkness was confirmed, the unevenness state was “◎”. Although some unevenness of light and darkness of a scale of about 5 mm to 10 mm is confirmed, if the product is acceptable, the unevenness state is “◯”, and unevenness of lightness and darkness is generally confirmed mottled, If the product is rejected, the uneven state is “x”.

  As shown in Table 1, if the average wind speed of the airflow flowing along the surface of the coating film 21 is 1 m / s, the drying time is about 1/5 compared to the case where the average wind speed is 0.1 m / s. It was shortened to. Moreover, if the average wind speed of the airflow flowing along the surface of the coating film 21 is 1 m / s, the drying time can be further reduced to about 1/10 compared to the case where the average wind speed is 0.1 m / s. It was.

  Moreover, as shown in Table 1, the turbulent intensity of the airflow flowing along the surface of the coating film 21 is 2% or less even when the average wind speed of the airflow flowing along the surface of the coating film 21 is 1 m / s or more. If so, the uneven state was “◯”, that is, it was possible to effectively prevent uneven coating from drying. Moreover, even if the average wind speed of the airflow flowing along the surface of the coating film 21 is 1 m / s or more, if the turbulent intensity of the airflow flowing along the surface of the coating film 21 is 1% or less, the uneven state is “◎”, that is, drying unevenness of the coating film could be more effectively prevented. On the other hand, even if the average wind speed of the airflow flowing along the surface of the coating film 21 is 1 m / s or more, if the turbulent intensity of the airflow flowing along the surface of the coating film 21 is 5%, the uneven state is “ × ”, that is, drying unevenness of the coating film could not be prevented. Therefore, in order to effectively prevent uneven coating drying without reducing the production efficiency, the turbulent strength of the airflow flowing along the surface of the coating film 21 is set to 2% or less, more preferably 1% or less. It can be said that it is extremely effective.

DESCRIPTION OF SYMBOLS 1 Liquid crystal sheet manufacturing apparatus 2 Coating apparatus 3 Coating-film hardening apparatus 4, 5, 6 Guide roller 10 Coating-film drying apparatus 11 Supply part 12 Exhaust part 13a Supply pipe 13b Exhaust pipe 14a Supply fan 14b Exhaust fan 15 rectifying passage 16 chamber 20 base material 21 coating film

Claims (18)

An air supply portion and an exhaust portion arranged to face each other;
The air supply part and the exhaust part form an airflow flowing along the surface of the coating film,
The coating film drying apparatus characterized in that the turbulent strength of the airflow is 2% or less. The coating film drying apparatus according to claim 1, wherein the turbulent strength of the airflow is 1% or less. The air supply part and the exhaust part are arranged facing each other along the traveling direction of the base material,
The coating film drying apparatus according to claim 1, wherein the direction of the airflow is the same as or opposite to the traveling direction of the base material. The coating film drying apparatus according to any one of claims 1 to 3, wherein a plurality of sets of the air supply unit and the exhaust unit are arranged along the traveling direction of the base material. The air supply unit has a plurality of rectifying passages bundled together,
The diameter d [mm] of each rectifying passage, the length L [mm] in the axial direction, and the wind velocity u [m / s] of the airflow satisfy the relational expression L / d ² ≧ 1950 × u. The coating film drying apparatus according to any one of claims 1 to 4. The air supply unit has a plurality of rectifying passages bundled together,
The diameter d [mm] of each rectifying passage and the length L [mm] in the axial direction satisfy a relational expression of L / d ² ≦ 24000. Membrane drying device. Forming an airflow that flows along the surface of the coating,
A method for drying a coating film, characterized in that the turbulent strength of the airflow is 2% or less. The coating film drying method according to claim 7, wherein the turbulent strength of the airflow is set to 1% or less. The method of drying a coating film according to claim 7 or 8, wherein the direction of the airflow is the same as or opposite to the traveling direction of the substrate. The method of drying a coating film according to any one of claims 7 to 9, wherein the air flow is formed at a plurality of locations along the traveling direction of the substrate. Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
The diameter d [mm] of each rectifying passage, the length L [mm] in the axial direction, and the wind velocity u [m / s] of the airflow satisfy the relational expression L / d ² ≧ 1950 × u. The method for drying a coating film according to any one of claims 7 to 10. Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
The diameter d [mm] of each rectifying passage and the length L [mm] in the axial direction satisfy a relational expression of L / d ² ≦ 24000, according to any one of claims 7 to 11. Membrane drying method. Applying liquid crystal to the surface of the substrate;
A step of drying the applied liquid crystal coating film;
With
In the drying step, an airflow flowing along the surface of the coating film is formed,
A method for producing a liquid crystal sheet, characterized in that the turbulent strength of the airflow is 2% or less. The method for producing a liquid crystal sheet according to claim 13, wherein the turbulent strength of the airflow is set to 1% or less. The method of manufacturing a liquid crystal sheet according to claim 13 or 14, wherein the direction of the airflow is the same as or opposite to the traveling direction of the base material. The method of manufacturing a liquid crystal sheet according to claim 13, wherein the air flow is formed at a plurality of locations along the traveling direction of the base material. Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
The diameter d [mm] of each rectifying passage, the length L [mm] in the axial direction, and the wind velocity u [m / s] of the airflow satisfy the relational expression L / d ² ≧ 1950 × u. The method for producing a liquid crystal sheet according to claim 13. Forming the air flow using an air supply unit having a plurality of rectifying passages bundled together;
18. The liquid crystal according to claim 13, wherein the diameter d [mm] of each rectifying passage and the axial length L [mm] satisfy a relational expression of L / d ² ≦ 24000. Sheet manufacturing method.

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