JP2022053325A - Film manufacturing method and film manufacturing device - Google Patents

Abstract

To provide a film manufacturing method and a film manufacturing device which can reduce poor appearance.SOLUTION: A film manufacturing method according to the present invention comprises: a step of coating a belt-like base material B being continuously conveyed in a longitudinal direction with coating liquid P; a step of thickening a coated film F formed by the coating, by spraying gas G to the coated film F; and a step of drying the coated film F. A maximum value of speeds of hitting-wind which is an ingredient in a direction perpendicular to the base material B at a surface position of the base material B of wind speeds of the gas is 2.0 m/s or more and 7.0 m/s or less. An average change rate determined from maximum values of the speeds of the hitting-wind in a range of 10 mm between front and rear sides in a conveying direction of the base material B at a position where the speeds of the hitting-wind becomes maximum is 0.25 m/(s.mm) or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a film manufacturing method and a film manufacturing apparatus.

A method is known in which a coating liquid in which a resin is dissolved in an organic solvent is applied onto a base material, and a coating film formed by the coating is dried to produce a resin film. When producing a film by such a method, it may be necessary to form a thick coating film having a thickness of 40 μm or more with an excellent appearance in order to obtain a required function.

It is known that by using a coating liquid having a low viscosity, poor appearance of the coating film is reduced from coating to drying due to the surface tension of the coating liquid and the like. However, if the viscosity is low, the coating film will flow after coating and the thick film cannot be maintained. On the other hand, if the viscosity is increased in order to obtain a thick film, the influence of coating unevenness (streaks, step unevenness) caused by bead defects in the coated portion becomes remarkable, and a coating film having an excellent appearance can be obtained. Can't.

The following Patent Document 1 describes a step of applying the paint to one surface of the support while moving the support (base film) relative to the coating position of the paint, and a step of applying the paint after the coating. A coating film forming method including at least a step of smoothing a coated surface by spraying a gas is described. According to Patent Document 1, it is possible to stop the flow and smooth the coated surface by spraying a gas on the coating film immediately after coating.

Japanese Unexamined Patent Publication No. 2004-261791

A film in which the coating film is smoothed can be obtained by the method described in Patent Document 1, but when applied to a coating film having a thick Wet film, wind prints are generated on the surface of the coating film, and the human eye. It is recognized as a poor appearance when viewed in. The wind pattern that causes such poor appearance becomes a defect when the obtained film is used as an optical film.

An object of the present invention is to provide a thick film film manufacturing method and a film manufacturing apparatus with reduced appearance defects.

As a result of diligent studies, the present inventors have found that a thick film film manufacturing method and a film manufacturing apparatus with reduced appearance defects are provided by the following configurations.

(1). It ’s a film manufacturing method.
A coating process in which a coating liquid containing a solvent-soluble resin and a solvent is applied onto a support using a coating means to form a coating film.
It has a thickening step of increasing the viscosity of the coating film by spraying a gas onto the coating film and a step of drying the coating film.
The maximum value of the collision wind speed, which is a component of the wind speed of the gas in the thickening step of increasing the viscosity of the coating film by spraying the gas in the direction perpendicular to the base material at the surface position of the base material, is 2.0 m. / S or more and 7.0 m / s or less,
A film manufacturing method in which the average rate of change from the maximum value of the collision wind speed at a position 10 mm before and after the transport direction of the base material at the position where the collision wind speed is maximum is 0.25 m / (s · mm) or less.

(2). The film manufacturing method according to (1), wherein the coating liquid has a viscosity of 1 to 50 cP.

(3). The film manufacturing method according to (1) or (2), wherein the temperature of the sprayed gas is 15 to 35 ° C.

(4). The film manufacturing method according to any one of (1) to (3), wherein the average thickness of the coating film is 80 μm or more and 200 μm or less.

(5). A transport device that continuously transports strip-shaped base materials in the longitudinal direction,
A coating device that applies a coating liquid to the base material transported by the transport device, and a coating device.
A thickening device for increasing the viscosity of the coating film by spraying a gas onto the coating film formed by the coating device is provided.
In the thickening device, the maximum value of the collision wind speed, which is a component of the wind speed of the gas in the direction perpendicular to the base material at the surface position of the base material, is 2.0 m / s or more and 7.0 m / s or less, and A film manufacturing apparatus that blows the gas so that the average rate of change from the maximum value of the collision wind speed at a position 10 mm before and after the transport direction of the base material at the position where the collision wind speed is maximum is 0.25 m / (s · mm) or less. ..

According to the present invention, it is possible to provide a thick film film manufacturing method and a film manufacturing apparatus with reduced appearance defects.

It is a schematic diagram which shows the structure of the film manufacturing apparatus which concerns on one Embodiment of this invention. It is a graph which shows the distribution of the collision wind speed in the prototype example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a film manufacturing apparatus according to an embodiment of the present invention.

The film manufacturing apparatus includes a transport device 1 that continuously transports the strip-shaped base material B (support) in the longitudinal direction, and a coating device 2 that coats the base material B conveyed by the transport device 1 with the coating liquid P. The thickening device 3 that increases the viscosity of the coating film F by spraying the gas G onto the coating film F formed by the coating device 2 and the coating film F that has been thickened by the thickening device 3 are dried. The drying device 4 is provided.

As shown in the figure, the transport device 1 can be configured to continuously transport a long strip-shaped base material by a plurality of transport rollers. In this case, the transport device 1 unwinds and transports the base material B wound on the reel, and winds the base material B after peeling off the product film formed by drying the coating film F on another reel. It may be configured to take.

The coating device 2 uniformly applies the coating liquid P to the surface of the base material B. Specifically, the coating device 2 may include, for example, a die coater, a knife coater, a bar coater, a gravure coater, or the like.

Although not particularly limited, in the illustrated example, the coating device 2 is configured to have a die 21 for discharging the coating liquid P supplied from a tank (not shown) over the entire width of the base material B.

As the coating liquid P applied to the base material B by the coating apparatus 2, a resin containing a resin as a main component of the functional film to be formed and an organic solvent for dissolving the resin can be used.

The resin contained in the coating liquid P is not particularly limited, but for example, when the obtained film is used for optical applications, acrylic resin, epoxy resin, urethane resin, silicon resin and the like are preferably used.

The weight average molecular weight of the resin contained in the early coating liquid P is preferably 500 to 20000, more preferably 2000 to 14000, and even more preferably 3000 to 12000. When the weight average molecular weight of the early resin is equal to or higher than the lower limit, the coating film F formed by the coating apparatus 2 can suppress the volatilization of the early resin. Further, when the weight average molecular weight of the resin in the first half is not more than the upper limit, an excessive increase in viscosity of the coating liquid P in the first half can be suppressed, and a thick film with reduced appearance defects can be obtained by the thickening device 3. ..

The viscosity of the coating liquid P is preferably 1 to 50 cP, more preferably 5 to 35 cP, and even more preferably 10 to 20 cP. When the viscosity is equal to or higher than the lower limit, the effect of thickening the coating film F formed by the coating device 2 can be sufficiently obtained by the thickening device 3. Further, when the viscosity of the early coating liquid P is not more than the upper limit, a thick film having reduced appearance defects can be obtained by the thickening device 3.

The solid content concentration of the early coating liquid P is preferably 30 to 70%, more preferably 40 to 60%, and even more preferably 45 to 55%. When the solid content concentration is at least the above lower limit, the coating film F formed by the coating device 2 does not become excessively thick, and the thickening device 3 can obtain a thick film with reduced appearance defects. Further, when the solid content concentration of the coating liquid P in the first half is not more than the above upper limit, the leveling effect can be sufficiently exhibited, and a thick film having reduced appearance defects can be obtained by the thickening device 3.

The organic solvent contained in the coating liquid P is not particularly limited, but for example, a solvent such as toluene, methyl isoethyl ketone or propylene glycol monomethyl ether is preferable. By using a solvent in such a boiling point region, it is desirable from the viewpoint of reducing the amount of residual organic solvent and equipment cost even when a product film having a relatively large thickness is produced.

It is necessary to reduce the viscosity of the coating liquid P in the coating portion in order to suppress the appearance defect. When the viscosity of the coating liquid P becomes low, it becomes difficult to form a thick film, but the thick film thickening device 3 enables thick film coating in which poor appearance is suppressed.

The lower limit of the average thickness of the coating film F formed by the coating device 2 is preferably 80 μm, more preferably 120 μm. On the other hand, the upper limit of the average thickness of the coating film F formed by the coating device 2 is preferably 200 μm, more preferably 160 μm. When the average thickness of the coating film F formed by the coating device 2 is at least the above lower limit, it is difficult to maintain the thick film of the coating film F and the appearance is liable to be poor. The effect of obtaining a reduced thick film becomes remarkable. Further, when the average thickness of the coating film F formed by the coating device 2 is not more than the upper limit, a thick film having reduced appearance defects can be obtained by the thickening device 3.

The lower limit of the average temperature (gas temperature) in the region where the gas G is sprayed (the sprayed region described later) by the thickening device 3 of the coating film F formed by the coating device 2 is preferably 15 ° C. and 20 ° C. Is more preferable. On the other hand, the upper limit of the average temperature of the coating film F formed by the coating device 2 is preferably 35 ° C, more preferably 25 ° C. By setting the average temperature of the coating film F formed by the coating device 2 to be equal to or higher than the lower limit, cooling is not required, so that an increase in equipment cost and running cost of the coating device 2 can be suppressed. Further, by setting the average temperature of the coating film F formed by the coating device 2 to be equal to or lower than the upper limit, a large amount of organic solvent is contained in the coating film F when the thick film is maintained by the thickening device 3 after coating. It is considered that it can be prevented from evaporating to prevent smoothing due to subsequent leveling.

The thickening device 3 maintains the thick film of the coating film F by spraying the gas G perpendicularly to the coating film F formed by the coating device 2.

The thickening device 3 has a nozzle 31 for injecting a gas G to be sprayed on the coating film F. The nozzle 31 has a slit-shaped outlet extending in a direction perpendicular to the transport direction of the base material B and parallel to the surface of the base material B (parallel to the width direction of the base material B), and a flow path immediately before the outlet. The dimension of the narrowing width (in the lateral direction of the outlet of the flow path) tapering toward the outlet decreases toward the outlet.

The lower limit of the maximum value of the collision wind speed, which is a component of the wind speed of the gas G in the direction perpendicular to the base material B at the surface position of the base material B, is preferably 2.0 m / s, more preferably 3.0 m / s. 3.8 m / s is more preferable. On the other hand, as the upper limit of the maximum value of the collision wind speed, 7.0 m / s is preferable, 6.0 m / s is more preferable, and 5.4 m is further preferable. By setting the maximum value of the collision wind speed to be equal to or higher than the lower limit, the thickness of the coating film F can be sufficiently maintained. Further, by setting the maximum value of the collision wind speed to be equal to or lower than the upper limit, it is possible to suppress the wind pattern on the surface of the coating film F and the scattering of the coating film. The collision wind speed is a value measured by an anemometer arranged at a position where the base material B is conveyed in the absence of the base material B.

Average change rate from the maximum value of the collision wind speed 10 mm before and after the transport direction of the base material B at the position where the collision wind speed is maximum (the average value of the value obtained by dividing the amount of change in the maximum wind speed by the front-rear distance 10 mm, hereinafter, before and after the peak The lower limit of the average rate of change) is preferably 0.02 m / (s · mm), more preferably 0.04 m / (s · mm), and even more preferably 0.06 m / (s · mm). On the other hand, the upper limit of the average rate of change before and after the peak is preferably 0.25 m / (s · mm), more preferably 0.20 m / (s · mm), and even more preferably 0.15 m / (s · mm). .. By setting the average rate of change before and after the peak to be equal to or higher than the lower limit, it is possible to prevent the range in which the gas G collides becomes too large while making the maximum value of the collision wind speed sufficiently large. Further, by setting the average rate of change before and after the peak to be equal to or less than the upper limit, the wind pattern is formed on the surface of the coating film F by suppressing the back-and-forth movement of the coating film F caused by the difference in wind power before and after the transport direction of the base material B. It can be suppressed.

The drying device 4 is a device for forming a resin film by drying the coating film F. As a method of drying the coating film F, a method of promoting vaporization of the organic solvent in the coating film F by warm air, radiant heat, or the like can be used.

As is clear from the above description, in the film manufacturing apparatus according to the embodiment of the present invention, the transport device 1 that continuously conveys the strip-shaped base material B in the longitudinal direction and the base material B that is conveyed by the transfer device 1 The coating device 2 for coating the coating liquid P and the thickening device 3 for thickening the coating film F by spraying the gas G onto the coating film F formed by the coating device 2 are provided. In the thickening device 3, the maximum value of the collision wind speed, which is a component of the wind speed of the gas G at the surface position of the base material B in the direction perpendicular to the base material, is 2.0 m / s or more and 7.0 m / s or less, and The gas G is injected so that the average rate of change from the maximum value of the collision wind speed at 10 mm before and after the position where the collision wind speed is maximum is 0.25 m / s or less. According to this film manufacturing apparatus, the thickness of the coating film can be maintained by keeping the maximum value of the collision wind speed within a predetermined range, and the average rate of change before and after the peak of the collision wind speed is small on the surface of the coating film F. It is possible to suppress the formation of wind patterns and reduce appearance defects.

Further, the film manufacturing apparatus of the present embodiment is an apparatus for carrying out the film manufacturing method of one embodiment of the present invention. That is, in the film manufacturing method of one embodiment of the present invention, a step of applying the coating liquid P to the strip-shaped base material B continuously conveyed in the longitudinal direction (coating step) and a coating formed by the coating are applied. A step of thickening the coating film F by spraying the gas G onto the film F (thickening step) and a step of drying the coating film F (drying step) are provided, and the base material B having a wind speed of the gas G is provided. The maximum value of the collision wind speed, which is a component in the direction perpendicular to the base material B at the surface position, is 2.0 m / s or more, and the collision wind speed at the position where the collision wind speed is maximum is 10 mm before and after the transport direction of the base material B. The average rate of change from the maximum value is 0.25 m / (s · mm) or less. According to this film manufacturing method, the thickness of the coating film can be maintained by keeping the maximum value of the collision wind speed within a predetermined range, and the wind pattern is formed on the surface of the coating film due to the small average rate of change. It can be suppressed and the appearance defect can be reduced.

In the film manufacturing method of one embodiment of the present invention, it is preferable that the average temperature of the coating film F when the gas G is sprayed is 15 ° C. or higher and 35 ° C. or lower. As a result, excessive drying of the coating film F is suppressed, so that a thick film film with suppressed appearance defects can be obtained.

In the film manufacturing method of one embodiment of the present invention, the average thickness of the coating film F is preferably 80 μm or more and 200 μm or less. As described above, when the thickness of the coating film is large, the effect of obtaining a thick film film having suppressed appearance defects becomes particularly remarkable.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and modifications can be made.

In the film manufacturing apparatus according to the present invention, the drying apparatus is not essential, and the coating film may be naturally dried.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

A reaction vessel was charged with 100 parts by weight of β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 0.12 parts by weight of magnesium chloride, 11 parts by weight of water and 11 parts by weight of propylene glycol monomethyl ether, and stirred at 130 ° C. for 3 hours. Then, degas under reduced pressure at 60 ° C. to obtain a siloxane resin, and obtain 100 parts by weight of the above siloxane resin, 2 parts by weight of a propylene carbonate solution of triarylsulfonium / SbF6 salt, and a xylene / isobutanol solution of a polyether-modified polydimethylsiloxane. A coating liquid containing 0.2 parts by weight and 100 parts by weight of propylene glycol monomethyl ether and having a viscosity adjusted to 10 cP is transferred to a substrate at a speed of 2.0 m / min with a die coater to obtain a WET film thickness immediately after coating. After coating to a thickness of 150 μm, the distribution of the impact wind velocity in the substrate transport direction is different as shown in FIG. 2 by controlling the blower, valve, nozzle and coating distance in the thickening device. The thickened film was heated and dried at 120 ° C. for 2 minutes, and then irradiated with ultraviolet rays so that the integrated light amount at a wavelength of 250 to 390 nm was 1000 mJ / cm ² using a high-pressure mercury lamp. A coated film was obtained by curing the film. The film thickness and appearance of the obtained film were evaluated.

The thickness is measured using a thickness measuring device "TOF-5R01" manufactured by Yamabun Denki Co., Ltd., and the average value is 75 μm or more, and the maximum deviation from the average value (the difference between the maximum value or the minimum value and the average value) is the average. Those having a value of 2% or less were regarded as "good", and those having an average value of less than 75 μm or a maximum deviation of more than 2% were regarded as "poor". As for the appearance, those in which the wind pattern was not visually recognized in the visual reflection and projection using the light source were regarded as "good", and those in which the wind pattern was visually recognized were regarded as "poor".

The wind speed distribution of the gas that collides with the coating film is perpendicular to the base material at each position on the surface on which the base material is transported, using the anemometer "Anemomaster 6162" manufactured by Kanomax Japan, in the absence of the base material. It was measured as the wind speed in the direction (collision wind speed).

FIG. 2 shows the distribution of the measured collision wind speed, and Table 1 below shows the type of resin used, the maximum value of the collision wind speed, the average rate of change before and after the peak, and the evaluation results of the film thickness and appearance. show.

From this result, when the maximum value of the collision wind speed is in a certain range and the average rate of change before and after the peak of the collision wind speed is less than a certain size, the film thickness of the obtained film is good and it depends on the wind pattern. It was confirmed that no appearance abnormality occurred.

1 Transfer device 2 Coating device 3 Thickening device 4 Drying device 11 Transfer roller 21 Die 31 Nozzle B Base material F Coating film G Gas P Coating liquid

Claims (5)

It ’s a film manufacturing method.
A coating process in which a coating liquid containing a solvent-soluble resin and a solvent is applied onto a support using a coating means to form a coating film.
It has a thickening step of increasing the viscosity of the coating film by spraying a gas onto the coating film and a step of drying the coating film.
The maximum value of the collision wind speed, which is a component of the wind speed of the gas in the thickening step of increasing the viscosity of the coating film by spraying the gas in the direction perpendicular to the base material at the surface position of the base material, is 2.0 m. / S or more and 7.0 m / s or less,
A film manufacturing method in which the average rate of change from the maximum value of the collision wind speed at a position 10 mm before and after the transport direction of the base material at the position where the collision wind speed is maximum is 0.25 m / (s · mm) or less. The film manufacturing method according to claim 1, wherein the coating liquid has a viscosity of 1 to 50 cP. The film manufacturing method according to claim 1 or 2, wherein the temperature of the sprayed gas is 15 to 35 ° C. The film manufacturing method according to any one of claims 1 to 3, wherein the average thickness of the coating film is 80 μm or more and 200 μm or less. A transport device that continuously transports strip-shaped base materials in the longitudinal direction,
A coating device that applies a coating liquid to the base material transported by the transport device, and a coating device.
A thickening device for increasing the viscosity of the coating film by spraying a gas onto the coating film formed by the coating device is provided.
In the thickening device, the maximum value of the collision wind speed, which is a component of the wind speed of the gas in the direction perpendicular to the base material at the surface position of the base material, is 2.0 m / s or more and 7.0 m / s or less, and A film manufacturing apparatus that blows the gas so that the average rate of change from the maximum value of the collision wind speed at a position 10 mm before and after the transport direction of the base material at the position where the collision wind speed is maximum is 0.25 m / (s · mm) or less. ..

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