JP2016097334A - Manufacturing method for functional film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a film which uses simultaneous multilayer coating and which can reduce haze.SOLUTION: A manufacturing method for a functional film includes: a coating film formation step of laminating a coating film on a base material by performing simultaneous multilayer coating of two or more coating liquids on the base material; and a drying step of drying the coating film. The manufacturing method for a functional film also includes a deaeration step of performing deaeration processing so that at least one dissolved oxygen concentration (DO) of adjacent layers out of the two or more coating liquids becomes equal to or less than the saturation dissolved oxygen concentration (SDO) in a maximum temperature of the coating film reached in the drying step, before the coating film formation step.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a functional film.

  A functional film formed by forming a layer that exhibits a desired function, such as a layer that reflects or absorbs light such as ultraviolet light, visible light, or infrared light, or a gas barrier layer, on the surface of the substrate is used in various applications. It's being used.

  As a method of manufacturing such a functional film, a method of forming using a dry film forming method such as a vapor deposition method or a sputtering method has been proposed. However, in the dry film forming method, a vacuum apparatus or the like used for forming becomes large, the manufacturing cost is high, and it is difficult to increase the area, and the base material is limited to a heat resistant material.

  A method of forming a functional film using a wet coating method is known instead of the dry film forming method having the above-described problems (see, for example, Patent Document 1).

  In general, as a method for producing a laminated film of two or more layers on a substrate by wet coating, there are sequential coating in which coating and drying are performed one layer at a time, and simultaneous multilayer coating in which a plurality of layers are coated simultaneously. Sequential coating includes spin coating, bar coating, blade coating, gravure coating, and the like. However, when a multilayer film is produced, productivity is low because the number of coating and drying increases.

  On the other hand, as simultaneous multilayer coating, there is a method using curtain coating, slide bead coating, or the like. Since a plurality of layers can be formed at the same time, productivity is high, and therefore simultaneous multilayer coating is preferably employed.

2009-86659

  As described above, simultaneous multi-layer coating has an advantage of high productivity, but the conventional method has a problem that the functional film to be produced has high haze.

  Therefore, it aims at providing the manufacturing method of the film which can reduce haze using simultaneous multilayer coating.

  The present inventors have intensively studied to solve the above problems.

  In the process, attention was paid to adjacent layers in the multilayer laminated structure.

  Functional films using a multi-layered structure, especially optical thin films such as infrared shielding films, are optical thin films that utilize the difference in refractive index between layers, so that adjacent layers do not mix and are separated. Is the ideal state.

  For the production of multilayer laminate structures by simultaneous multi-layer coating, it is better to immobilize the layers by drying as soon as possible after simultaneous coating in order to suppress mixing between layers, and at least higher than the liquid temperature at the time of coating It is usual to dry with.

  The present inventors paid attention to this drying.

  As the film surface temperature rises in the drying process, the present inventors increase the liquid temperature of the coating film in the middle of drying, thereby reducing the amount of saturated dissolved oxygen in the coating film. The amount of dissolved oxygen in (2) is larger than the saturation amount, and fine bubbles are generated by the foaming phenomenon. As a result, there is a problem that haze increases.

  In other words, if the dissolved oxygen concentration of the coating solution forming the multilayer is adjusted in advance so that it will be in an unsaturated state even in the highest temperature environment reached in the drying process, the temperature of the coating solution will rise and saturated dissolved oxygen will increase. It was thought that even if the concentration was decreased, saturation was not reached and the foaming phenomenon could be suppressed, and consequently the haze problem could be solved.

  That is, the said subject is a coating-film formation process which laminates | coats a coating film on the said base material by simultaneously apply | coating two or more coating liquids on a base material, and drying the said coating film, The drying process And a method for producing a functional film, wherein, prior to the coating film forming step, at least one dissolved oxygen concentration (DO) that becomes an adjacent layer among the two or more coating solutions. It can be solved by a method for producing a functional film, further comprising a degassing step, wherein the degassing treatment is performed so that the concentration of dissolved dissolved oxygen (SDO) at the maximum temperature of the coating film reached in the drying step is not more than The present invention has been completed.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the film which can reduce a haze using simultaneous multilayer coating can be provided.

It is a schematic block diagram of the infrared shielding film manufacturing system which concerns on embodiment of this invention. It is a figure which shows the example of the deaeration apparatus using a hollow fiber membrane. It is the schematic of the slide bead application system using the slide type coater for simultaneous multilayer application.

  Embodiments of the present invention will be described below. In addition, this invention is not limited only to the following embodiment. Unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50%.

  The present invention comprises: a coating film forming step of laminating a coating film on the substrate by simultaneously applying two or more coating solutions on the substrate; and a drying step of drying the coating film; In the method for producing a functional film, before the coating film forming step, at least one dissolved oxygen concentration (DO) that becomes an adjacent layer among the two or more coating liquids, It is a manufacturing method of a functional film which further has a deaeration process which carries out a deaeration process so that it may become below a saturation dissolved oxygen concentration (SDO) in the maximum temperature of the above-mentioned coating film reached in a drying process. In the present specification, “simultaneous multilayer coating” may be simply referred to as “coating”.

  As described above, the dissolved oxygen concentration of the coating liquid on at least one side of the adjacent layers of the coating liquid to be laminated is applied to the maximum temperature of the coating liquid between the time when the coating liquid is applied on the substrate and the end point of drying. By performing deaeration treatment so as to be equal to or lower than the saturated dissolved oxygen concentration (SDO) value of the liquid, it is saturated even if the temperature of the coating liquid rises and the saturated dissolved oxygen concentration (SDO) decreases. The foaming phenomenon can be suppressed without reaching, and the haze problem can be solved.

  Here, the “drying step” in the present invention usually starts from a “drying start point” at which drying is started and ends at a “drying end point” at which drying is completed. In this case, the “drying end point” basically means a point at which the evaporation of the solvent (particularly moisture) from within the coating film becomes substantially zero. “Evaporation of solvent (especially moisture) is substantially zero” means that the amount of solvent (especially moisture) evaporation on the coating surface is measured several times and the amount of change disappears (equilibrium) In other words, according to an embodiment of the present invention, the “drying end point” is determined by examining the change in the amount of solvent (particularly, moisture) on the coating film surface using an infrared moisture meter. Can be examined. However, the concept of the “drying step” in the present invention is not only performed for the purpose of volatilizing the solvent, but for example, after the coating solution is applied on the substrate until the substrate is wound up. In some cases, heat treatment is performed for the purpose of increasing the strength of the coating film.

  Further, in the present invention, “at least one of the two or more coating liquids that are adjacent to each other” will be described in detail. For example, using two liquid coating liquids, In the case of producing a coating film, it means any one or both of two coating liquids (that is, all coating liquids to be applied simultaneously in multiple layers). In addition, when a three-layer coating film is prepared on a substrate using a three-component coating solution, only the coating solution serving as the center layer, the coating solution serving as the lowermost layer, and the uppermost layer are formed. The form of a coating liquid and the form of all the coating liquids apply | coated by simultaneous multilayer coating are considered. In addition, when a four-layer coating solution is used to form a coating film consisting of four layers on the substrate, the lowermost coating solution and the second layer (one layer below the uppermost layer) and The form of the coating liquid to be formed, the form of the coating liquid to be the third layer (upper layer as viewed from the lowermost layer) and the form of the coating liquid to be the uppermost layer, the form of the coating liquid to be any three layers, The form of all coating liquids to be applied in multiple layers is conceivable.

  More typically, in the form of an infrared shielding film in which a high refractive index layer and a low refractive index layer are alternately laminated as described later, a coating liquid and a low refractive index layer that become a high refractive index layer Either or both forms of the coating solution are considered.

  In the present invention, the “maximum temperature of the coating film reached in the drying process” is the highest temperature given to the coating film laminated on the substrate in the “drying process” described above. . Although there is no particular limitation on the method for measuring the maximum temperature, for example, a method for measuring the surface temperature of the coating film using a non-contact type thermometer as used in the examples of the present application is suitable. It is.

  The functional film produced by the above production method has a coating film formed by laminating two or more coating liquids simultaneously on a base material, and uses the coating film as a functional layer. be able to.

  For example, it has a configuration in which a laminate including a high refractive index layer and a low refractive index layer is disposed on a substrate, and the optical film thickness (film thickness × refractive index) of the high refractive index layer and the low refractive index layer is set. By appropriately controlling, a light beam having a specific wavelength can be reflected.

  Thereby, the functional film becomes an optical reflection film, and when the optical reflection film reflects light (ultraviolet light) having a wavelength of 200 to 400 nm, for example, the functional film becomes an ultraviolet shielding film, and light having a wavelength of 400 to 700 nm (visible light). ) Can be a visible colored film, and when reflecting light (infrared rays) having a wavelength of 700 to 1200 nm, it can be an infrared shielding film. In addition, by appropriately designing the film thickness and the like, the wavelength and reflectance of the reflected light beam can be controlled to obtain a metallic glossy film. Among these, the light ray that can be shielded by the optical reflection film is preferably a light ray having a wavelength of 200 nm to 1000 μm in the ultraviolet to infrared region, more preferably a light ray having a wavelength of 250 to 2500 nm, and a wavelength of 700 to 1200 nm. The light in the near infrared region is more preferable.

  In the following explanation, as a typical example of “functional film”, solar cells are installed on the window glass of buildings and vehicles from the viewpoint of reducing the load on cooling equipment due to the recent increase in interest in energy saving measures. The “infrared shielding film” whose demand for blocking the transmission of heat rays is increasing will be described, but the present invention is not limited thereto.

<Infrared shielding film manufacturing system>
FIG. 1 is a schematic configuration diagram of an infrared shielding film system according to the first embodiment.

  The infrared shielding film manufacturing system 1 is configured by connecting a plurality of devices, and manufactures an infrared shielding film through a plurality of steps realized by each device. In the example shown in FIG. 1, the infrared shielding film manufacturing system 1 roughly performs a preparation process, a dispersion process, a supply process, and a coating process. The coating process includes a coating film forming process and a drying process, which will be described later. Hereinafter, the structure and operation of the apparatus included in each process will be described.

[Preparation process]
In the preparation process, the infrared shielding film manufacturing system 1 prepares a coating solution in which “water-soluble polymer” and “metal oxide particles” that form the optical functional layer of the infrared shielding film are dispersed. The preparation process includes a preparation pot 101, a liquid feeding device 102, a dispersion device 103, and a filtration device 104.

  The preparation pot 101 is a container for preparing a coating solution. The method for preparing the coating solution is not particularly limited, and is, for example, a method in which an additive such as a water-soluble polymer, metal oxide particles, and, if necessary, a curing agent is added to a solvent and stirred. At this time, the order of addition of the respective components is not particularly limited, and the respective components may be sequentially added and mixed while stirring, or may be added and mixed at one time while stirring. The method for preparing these coating solutions is appropriately determined for each coating solution. The preparation tank 101 is connected to the downstream storage tank 105 in order to supply the coating liquid to the storage tank 105 included in the dispersion step.

  The liquid feeding device 102 is provided on a transport path L0 for transporting the coating liquid from the preparation pot 101. The liquid feeding device 102 is, for example, a rotary pump such as a Kia pump, a Mono pump, or a rotary pump, and can control feeding of the prepared coating liquid and stopping of the liquid feeding. Further, the liquid feeding device 102 can appropriately set the flow rate and speed of the coating liquid when feeding the coating liquid. In the present embodiment, for example, a chemical gear pump GX series (manufactured by Iwaki Co., Ltd.) is used as a gear pump, and the discharge pressure and flow rate can be appropriately set and used. Here, the flow rate is not particularly limited.

  The dispersion device 103 is provided on the transport path L0. The dispersion device 103 performs a dispersion process (including a shearing process) on the coating liquid. As a result, the coating solution breaks the bonds (van der Waals bonds, etc.) between the molecules of the water-soluble polymer and the end groups in the molecule, thereby eliminating the entanglement between the molecules, and as a result, reducing the viscosity, etc. Adjust the physical properties of the coating solution. The dispersion device 103 is not particularly limited as long as it can disperse and shear the coating solution, and may be a mild emulsifier, a pressure homogenizer, a high-speed rotational shear homogenizer, or the like as a commercially available emulsification dispersion device. There is no particular limitation on the rotation speed.

  The filtration device 104 is provided on the transport path L0. The filtering device 104 removes foreign matters mixed in the coating liquid, and foreign matters due to bubbles or aggregation generated in the coating liquid.

  In this embodiment, although the dispersion apparatus 103 and the filtration apparatus 104 were demonstrated on the conveyance path | route L0, these were abbreviate | omitted and these were abbreviate | omitted and used the liquid feeding apparatus 102 directly from the coating liquid preparation pot 101. Then, the coating liquid may be sent to the storage tank 105.

[Dispersion process]
The infrared shielding film manufacturing system 1 circulates and disperses the prepared coating liquid while maintaining appropriate physical properties in the dispersion step. The dispersion step preferably includes a circulation path R1 for returning the coating liquid conveyed from the storage tank 105, the liquid feeding apparatus 106, the dispersion apparatus 107, the filtration apparatus 108, and the deaeration apparatus 118 to the storage tank 105 again.

  The storage tank 105 stores the coating liquid so that the coating liquid can be continuously supplied. The storage tank 105 is preferably provided with a stirring device for circulating the coating liquid even inside the storage tank 105. Thereby, the physical property of the coating liquid in the storage tank 105 can be made uniform. The storage tank 105 is connected to a circulation path R <b> 1 for conveying the coating liquid from the storage tank 105 and returning the conveyed coating liquid to the storage tank 105 again. The storage tank 105 is connected to a supply path L1 for sending the coating liquid to the downstream supply process and the coating process.

  The liquid feeding device 106 is provided on the circulation path R1. The liquid feeding device 106 is, for example, a pump. In the present embodiment, a rotary pump such as a gear pump similar to the liquid feeding device 102 may be used. There is no particular limitation on the rotation speed. The liquid feeding device 106 controls the feeding of the coating liquid stored in the storage tank 105 and the stop of the liquid feeding. Further, the liquid feeding device 106 can appropriately set the flow rate and speed of the coating liquid when feeding the coating liquid.

  The dispersion device 107 is provided on the circulation path R1. The dispersion device 107 may have a configuration similar to that of the dispersion device 103, and performs dispersion and shearing processing on the coating liquid. In the present embodiment, for example, a milder disperser MDN306 (manufactured by Taiheiyo Kiko Co., Ltd.) is used as a milder disperser, and dispersion and shearing treatment can be performed on the coating solution fed through the circulation path R1.

  The filtering device 108 removes foreign matters mixed in the coating liquid, and foreign matters due to bubbles or aggregation generated in the coating liquid. The coating liquid from which the foreign matter has been removed returns to the storage tank 105 through the circulation path R1.

(Deaeration process)
The deaerator 118 is provided on the circulation path R1. That is, according to a preferred embodiment, the deaeration process is performed in a circulation path for circulating the coating liquid.

  In the deaeration process, the deaeration process performed using the deaerator 118 reduces the dissolved oxygen concentration in the coating solution.

  The degassing treatment is preferably performed by a vacuum degassing method, and among them, a vacuum degassing method using a hollow fiber membrane is preferable.

  In addition, as a vacuum deaeration method that does not use a hollow fiber membrane, for example, the coating liquid is put into a vacuum kettle having a pressure reducing function and a stirring function, and stirring is performed so that the coating liquid flows as a whole. There are a vacuum degassing method for degassing by depressurization, a centrifugal degassing method using centrifugal force, and the like, and the deaeration treatment can be performed by selecting and using a method as appropriate or in combination. As the degassing treatment, at least one dissolved oxygen concentration (DO), which is an adjacent layer among two or more coating solutions, is saturated dissolved oxygen concentration (SDO) at the highest temperature of the coating film reached in the drying step. ) Perform deaeration treatment so that The “maximum temperature of the coating film” can be obtained by preparing a sample in advance under the same production conditions as the operating conditions and measuring the maximum temperature reached at that time. Specifically, for example, it is performed as described in the examples.

  In the present invention, it is preferable to perform the degassing treatment on at least one of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer. Moreover, it is more preferable to perform the deaeration process on all coating solutions to be applied simultaneously.

  In addition, as a vacuum degassing method using a degassing membrane (particularly, a hollow fiber membrane), the coating liquid is fed while reducing the space facing the coating liquid through the gas permeable membrane to below atmospheric pressure. As a result, the coating solution is degassed.

  Similarly, as the deaeration condition using the hollow fiber membrane, the highest concentration of the coating film that reaches at least one dissolved oxygen concentration (DO), which is an adjacent layer among the two or more coating liquids, is achieved in the drying step. A deaeration process is performed so that it may become below the saturated dissolved oxygen concentration (SDO) in temperature.

  Note that, regardless of the form of the degassing treatment, as a result of measuring the dissolved oxygen concentration (DO), the saturated dissolved oxygen concentration at the highest temperature of the coating film reached by the dissolved oxygen concentration (DO) in the drying step. When it is higher than (SDO), it is preferable to change the conditions of the deaeration treatment so as to be lower than the saturated dissolved oxygen concentration (SDO). That is, according to this invention, the manufacturing method which measures the dissolved oxygen concentration (DO) of the said coating liquid and changes the conditions of the said deaeration process according to the result is also provided.

  The gas permeable membrane as described above is preferably made of a material that is non-porous, has excellent gas permeability, and has chemical resistance to the coating solution. Specifically, as the material, a material mainly composed of fluororesin or polyolefin is preferably used. The hollow fiber membrane may have a multilayer structure.

  There are roughly two types of degassing methods using a hollow fiber membrane: an internal perfusion method in which a coating solution is passed through the hollow fiber membrane and the outside is decompressed; There is an external perfusion method in which the side is decompressed and the coating solution is passed outside. Either of these methods can be used, but since the liquid can be handled with a relatively high viscosity and the processing flow rate can be increased, the external perfusion method can be preferably used.

  FIG. 2 is a diagram showing an example of an external perfusion type deaeration device 9 using a hollow fiber membrane. The deaeration module 91 has a hollow fiber membrane 92 inside. The inside of the deaeration module 91 is decompressed by the decompression pump VP. As shown by the arrows in FIG. 2, the coating liquid is sent into the degassing module 91 from the liquid feeding pipe 21a, and flows out of the hollow fiber membrane 92 in a disorderly manner, increasing the contact frequency between the dissolved oxygen and the degassing membrane. It will be in the state. Under this state, the dissolved oxygen passes through the inside of the hollow fiber 92 and is discharged to the outside, whereby the coating solution is degassed.

As the deaeration module 91, a commercially available product may be purchased, and a deaeration membrane module SEPAREL (separel) manufactured by DIC Corporation, a deaeration membrane module Superphobic (registered trademark), etc., manufactured by Polypore is suitable. . As Superphobic made by Polypore, 4 × 28 (membrane area 21.7 m ² ) 18 to 113 L / min, 4 × 13 (membrane area 8 m ² ) 10 to 50 L / min, 2 × 6 (membrane area 0. 5 m ² ) to 1 L / min, etc. are suitable, and as SEPAREL series manufactured by DIC, EF-020G (membrane area 20 m ² ) 8 to 50 L / min, EF-G5 (membrane area 0.5 m ² ) to 1 L / min or the like is preferable. Two or more of these are preferably used in parallel.

  Further, the degree of decompression of the deaeration film is not particularly limited as long as it is a condition that provides a dissolved oxygen concentration (DO) lower than the saturated dissolved oxygen concentration (SDO), but may vary depending on the composition of the coating solution. As a guideline, 10 to 500 Torr is preferable, 10 to 200 Torr is more preferable, and 10 to 100 Torr is more preferable.

  In addition, the degassing membrane circulation time is not particularly limited as long as the dissolved oxygen concentration (DO) is lower than the saturated dissolved oxygen concentration (SDO), depending on the composition and amount of the coating solution. Can be changed. From the viewpoint of uniformly degassing the treatment liquid, in the case of treatment in a circulation system, treatment is preferably performed for a time equivalent to one circulation or more of the total liquid amount.

  Degassing so that the dissolved oxygen concentration (DO) is equal to or lower than the saturated dissolved oxygen concentration (SDO) at the maximum temperature of the coating film reached in the drying step while appropriately changing and adjusting the degassing conditions as described above. Process.

  The timing of measuring the dissolved oxygen concentration (DO) is not particularly limited as long as it is before the drying process, but from the viewpoint of being able to easily collect the coating liquid as close to the drying process as possible, the coating liquid storage tank 105 It is preferable to perform the measurement by sampling the coating solution and adjusting the solution temperature to the temperature at the time of coating.

  In addition, when using the deaeration apparatus using a hollow fiber membrane, it is especially good to perform the filtration process by the filtration apparatus 108 demonstrated above. The deaeration membrane has a structure in which the liquid passes through the pore channel in order to enhance the deaeration ability. For this reason, if there is a foreign substance or the like in the coating liquid, it may become clogged and the coating liquid may not be sent. In order to avoid this clogging, the filtration process is effective. In addition, it is effective that the large foam is further crushed in the filtration process or a secondary effect that it can be captured by the filter, so that the filtration process is performed before the deaeration process by the deaeration membrane. is there. Thus, in this invention, it is also effective to combine a deaeration device and a filtration device.

  According to a preferred embodiment of the present invention, at least one of the deaeration processes is performed using a deaeration membrane. The deaeration process may be performed in combination with a deaeration membrane and other deaeration means such as the above-described decompression kettle. In addition, since the degassing membrane can be introduced into the system simply and inexpensively and can be efficiently degassed, it is preferable that two or more units of the degassing membrane be arranged in parallel. The upper limit for arranging in parallel is not particularly limited, but is about 2 to 4 units because, for example, the processing flow rate can be increased, that is, switching can be performed without stopping when it occurs.

  As described above, in the dispersion step, the coating liquid is transported from the storage tank 105 to the circulation path R1, subjected to processing by the dispersion apparatus 107, the filtration apparatus 108, and the deaeration apparatus 118, and then returns to the storage tank 105. The coating liquid returned to the storage pot 105 moves while being stirred in the storage pot 105, and is then conveyed again to the circulation path R1, and the above processing is repeated.

  In addition, the processing strength of the dispersion device 107 and the filtration device 108 in the dispersion step was such that the physical properties of the coating liquid were kept within an appropriate range depending on conditions such as the use of the infrared shielding film and the properties of the coating liquid used. Can be set as appropriate.

  In FIG. 1, the devices are arranged in the order of the dispersion device 107 and the filtration device 108 on the circulation path R1. However, the order of these devices can be changed as appropriate. Moreover, you may make it arrange | position only about a dispersion | distribution process about the apparatus which has the function which overlaps with a preparation process and a dispersion | distribution process. For example, the dispersion apparatus 103 and the filtration apparatus 104 in the preparation process may be omitted because there are apparatuses having the same function in the dispersion process. In addition, in the dispersion process, devices other than those described above, for example, bubbles removed in the coating solution and dissolved oxygen dissolved in the coating solution, defoaming / degassing using centrifugal force, reduced pressure or ultrasonic waves are removed. An apparatus may be provided.

[Supply process]
In the infrared shielding film manufacturing system 1, the coating liquid dispersed in the dispersing step is supplied to the downstream coating step through this supply step. The supply process includes a liquid delivery device 109, a flow meter 110, a filtration device 111, and a supply path L1. The supply path L1 is a path for supplying the coating liquid from the storage tank 105 of the dispersion process to the coating process. The liquid feeding device 109, the flow meter 110, and the filtration device 111 are provided on the supply path L1.

  The liquid feeding device 109 is stored in the storage tank 105 in the dispersion step and sends the dispersed coating liquid to each device provided in the supply path L1. The liquid feeding device 109 is a rotary pump such as a gear pump, for example, and can control feeding of the prepared coating liquid and stopping of the liquid feeding. The liquid feeding device 109 can appropriately set the flow rate and speed of the coating liquid when feeding the coating liquid.

  The flow meter 110 is a device that measures the flow rate of the coating liquid passing through the supply path. Depending on the flow rate of the coating liquid measured by the flow meter 110, the flow rate by the liquid feeding device 109 may be appropriately controlled. As the flow meter, for example, a flap type, a hot wire type, a Karman vortex type, or a negative pressure sensing type flow meter is used. A pressure gauge that measures the pressure of the coating liquid in the supply path may be provided in addition to the flow meter or instead of the flow meter.

  The filtering device 111 removes foreign matters mixed in the coating liquid, and foreign matters caused by bubbles or aggregation generated in the coating liquid. The coating liquid from which the foreign matter has been removed is sent to the downstream coating process through the supply path L1.

  In FIG. 1, the devices are arranged in the order of the flow meter 110 and the filtering device 111 on the supply path L1. However, the order of these devices can be changed as appropriate. In addition, the supply process may be provided with a device other than the above, such as a defoaming device, and the filtration device 111 may not be provided among the above devices.

[Coating process]
In the coating process, the infrared shielding film manufacturing system 1 applies a coating solution to a substrate to produce a coating film. In the present invention, the coating step includes at least a coating film forming step and a drying step. The coating film forming process is performed by the coating apparatus 112, and the drying process is performed by the drying apparatus 114. In the present embodiment, a setting process using the setting apparatus 113 may be provided between the coating film forming process using the coating apparatus 112 and the drying process using the drying apparatus 114.

  The coating device 112 simultaneously coats the coating solution on the substrate. Thus, in order to apply | coat a coating liquid on a base material in multiple layers, the coating liquid piled up at least adjacently is prepared by different distribution and material. Therefore, FIG. 1 shows one preparation pot 101, but actually, a plurality of preparation pots are prepared, and a plurality of types of coating liquids are applied to the coating apparatus 112 through separate preparation steps, dispersion steps, and supply steps. To be supplied.

(Coating film formation process)
In the present invention, two or more kinds of coating liquids are applied simultaneously on the substrate. The simultaneous multilayer coating means a method of forming a plurality of coating liquids constituting different layers by supplying them simultaneously to the coating apparatus from the stage of the coating process as described above. Therefore, it is different from a method of applying wet coating in multiple steps sequentially, that is, a method of applying multiple layers by wet-on-wet method and then drying at the same time.

  The coating method is not particularly limited as long as simultaneous multilayer coating can be performed. For example, roll coating method, rod bar coating method, air knife coating method, spray coating method, curtain coating method, or slide bead coating described in US Pat. Nos. 2,761,419 and 2,761,791 A method, an extrusion coating method or the like is preferably used. Since it is necessary to form a multilayer in the infrared shielding film, a curtain coating method or a slide bead coating method is preferable.

  Specifically, a simultaneous multilayer slide type coater that can be used in the present invention will be described with reference to FIG.

  FIG. 3 is a schematic view of a slide bead coating method using the slide type coater 1a. FIG. 3A is a schematic diagram of a slide bead coating method in which a slide coater 1a is used to apply to a holding portion of a support body whose opposite surface is held by a back roll. FIG. 3B is a schematic view of the slide surface of the slide type coater 1a shown in FIG. FIG. 3C is an enlarged schematic cross-sectional view of a portion indicated by X in FIG. Further, reference numeral 1a in FIG. 3A shows a configuration of four dice.

  FIG. 3 shows a slide type coater 1a, 2 shows a back roll, and 3 shows a belt-like support (base material) that runs continuously. The arrow indicates the transport direction of the belt-like support 3. Reference numeral 11 denotes a die (bar) constituting the slide type coater 1a. In the case of this figure, the four types of bars 11a to 11d constitute the slide type coater 1a. The number of dies is not fixed, but can be increased or decreased depending on the number of layers to be applied.

  The die 11 a has a lip portion 13 that faces the belt-like support 3. Reference numeral 12 denotes a slit which is an outlet of the coating liquid formed between the dies. In the case of this figure, the slits 12a to 12c are formed between four dies 11a to 11d. Reference numerals 12a1 to 12c1 denote edge portions of the exits of the respective slits. Reference numeral 14 denotes a pocket provided in the slit for uniformly extruding the coating liquid sent from the supply pipe 43 in the width direction from the slit 12. 14a-14c shows the pocket provided in each slit 12a-12c. Reference numeral 15 denotes a slide surface of the coater constituted by the front end surface of each bar. In the case of this figure, slide surfaces 15a to 15d are constituted by the respective dies 11a to 11d. Reference numerals 17 a and 17 b denote edge guides provided at both ends of the slide surface 15. The coating liquid prepared in the preparation tank 41 of the coating liquid supply system 4 is supplied to a pocket 14 formed in each slit through a supply pipe 43 by a liquid feed pump 42.

  In addition, from the preparation pot 41 of the coating liquid supply system 4 to the supply to the pocket 14 formed in each slit, the preparation process, the dispersion process including the deaeration process, and the supply process described above are performed. .

  The coating liquid pushed out from each slit is regulated in width by the edge guides 17a and 17b, flows down the slide surface 15, and a lip portion 13 forms a coating liquid reservoir called a bead 16 between the belt-like support member. Is applied to the holding part of the support 3 which is held and conveyed by the back roll 2 via the back roll 2. Since application is performed through the bead in this way, it is also referred to as slide bead application. The maximum tilt angle of the slide surface is about 30 degrees.

  Reference numeral 17c denotes a surface in contact with the coating liquid of the edge guide 17a (hereinafter also referred to as a liquid contact surface), and 17d denotes a liquid contact surface of the edge guide 17b. Since the uniformity of the coating width is regulated by the edge guides 17a and 17b, it is preferable to provide the edge guides 17a and 17b in the coating method using the slide type coater 1a.

  5a shows the coating film apply | coated to the support body. Reference numeral 6 denotes a decompression chamber provided in the lower part of the slide type coater for stabilizing the bead formation, and 61 denotes a suction pipe.

  In FIG. 3C, the coating liquid flowing through the slit 12a is defined as coating liquid A, the coating liquid flowing through the slit 12b is defined as coating liquid B, and the coating liquid flowing through the slit 12c is defined as coating liquid C.

  In the present invention, as described above, the coating film that reaches at least one dissolved oxygen concentration (DO), which becomes an adjacent layer among the two or more coating liquids, in the drying process before the coating film forming process. Is deaerated so as to be equal to or lower than the saturated dissolved oxygen concentration (SDO) at the maximum temperature. Therefore, in the form shown in FIG. 3, “application liquid A and application liquid C” or “application liquid B only” or “all of application liquid A, application liquid B, and application liquid C” reaches in the drying process. Deaeration treatment is performed in advance so as to be equal to or lower than the saturated dissolved oxygen concentration (SDO) at the maximum temperature of the membrane.

  When the coating method is simultaneous multi-layer coating using the slide bead coating method as described above, the viscosity of the coating solution is preferably 1 to 1,000 mPa · s, and preferably 1 to 500 mPa · s. Is more preferable. In particular, the effect of the present invention is particularly exerted when using a highly viscous coating solution in which at least one viscosity of the coating solution is 100 cP or more. Of the low refractive index layer coating solutions, the viscosity of the low refractive index layer coating solution used for the lowermost layer is preferably 1 to 200 mPa · s, and more preferably 1 to 100 mPa · s. . In addition, the measuring method of a viscosity follows the method of an Example.

  The coating temperature is preferably 20 to 60 ° C. A coating temperature of 60 ° C. or lower is preferable because facilities for keeping the coating solution at a high temperature can be relatively simplified and costs can be reduced. On the other hand, it is preferable that the coating temperature is 20 ° C. or higher because a facility for cooling the coating solution becomes unnecessary, the cost can be suppressed, and the safety of the work can be improved.

  The coating speed is preferably 1 m / min or more, and more preferably 1 to 500 m / min. A coating speed of 1 m / min or more is preferable because high productivity can be obtained. Moreover, it is preferable from being 500 m / min or less from being able to apply | coat stably.

  Further, the thickness of each layer at this time is not particularly limited, but in the case of a low refractive index layer, 50 to 1,000 nm is preferable, and 50 to 500 nm is more preferable. Moreover, in the case of the low refractive index layer used for the lowest layer, 50-2,000 nm is preferable and 50-1,000 nm is more preferable. In the case of a high refractive index layer, 50 to 1,000 nm is preferable, and 50 to 500 nm is more preferable.

(Set process)
The setting device 113 in FIG. 1 once cools the coating liquid formed on the substrate.

  Since the coating solution immediately after coating has a low viscosity, when hot air is applied and dried immediately after coating, the film thickness may partially change due to the hot air, and a uniform refractive index or the like may not be obtained over the entire surface. In addition, when multi-layer coating is performed, the components move between the layers, and the boundary between the layers can be vague enough to adversely affect the desired optical performance. However, once the coating film is cooled and thickened, the film thickness does not change even when hot air is applied to it, and the boundary between layers is prevented from becoming ambiguous enough to adversely affect the desired optical performance. it can. In addition, in the infrared shielding film manufacturing system 1, the setting apparatus 113 may be abbreviate | omitted.

(Drying process)
In the drying step, basically, the solvent of the coating solution is removed by drying to increase the solid content concentration, thereby increasing the viscosity of the coating solution. As described above, the drying device 114 dries the coating film on the base material, further stabilizes it, and completes it as an infrared shielding film.

  In the heat drying, the coating liquid is dried by heating the coating liquid and applying air as necessary. The heating temperature may be appropriately selected depending on the composition of the coating solution, but is usually about 15 to 100 ° C, preferably 20 to 95 ° C. Since the drying temperature at this time greatly affects the coating film, in the present invention, the dissolved oxygen in the coating solution is set to be equal to or lower than the saturated dissolved oxygen concentration (SDO) at the maximum temperature of the coating film reached in the drying step. It is characterized in that the density (DO) needs to be reduced in advance.

  The heating means is not particularly limited, and examples include heating with a dryer, providing a drying zone to heat-dry the coating film, and heating with an infrared heater. When a slide type coater is used, it is preferable to provide a heating / vacuum drying zone immediately after the back roll because heating / vacuum drying of the coating liquid can be performed quickly and interlayer mixing can be suppressed. Since the installation of equipment is simple and the method is simple, it is more preferable to thicken the thickened coating solution by heat drying.

  Subsequently, the composition of the coating solution will be described.

  Conventionally known materials can be used as the material for forming the coating liquid for forming the coating film, and examples thereof include metal oxide materials, water-soluble polymers, other additives, and combinations thereof.

In the infrared shielding film in the present embodiment, the metal oxide material includes TiO ₂ , ZrO ₂ , Ta ₂ O _{5 and the} like as the high refractive index material, and SiO ₂ , MgF _{2 and the} like as the low refractive index material. Is mentioned.

  In the infrared shielding film of the present embodiment, the high refractive index layer including the first water-soluble polymer and the first metal oxide particles, the second water-soluble polymer, and the second water are formed on the substrate. Low refractive index layers containing metal oxide particles are alternately stacked.

  In such a form, for example, materials similar to those described in International Publication No. 2013/054912, JP2013-148849A, JP2013-142089A, and the like are used.

  Specifically, in the first embodiment, the first water-soluble polymer and the second water-soluble polymer can be applied in an aqueous system without using an organic solvent, so that there is little environmental burden and flexibility. Since it is high, the durability of the film during bending is improved, which is preferable. Examples of the water-soluble polymer include polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, Or acrylic resin such as acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene -Acrylic acid copolymer or styrene acrylic resin such as styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-sodium styrenesulfonate copolymer, styrene-2-hydroxyethyl acrylate copolymer Coalescence, styrene-2 -Hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate -Synthetic water-soluble polymers such as maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate copolymers such as vinyl acetate-acrylic acid copolymers and their salts; gelatin, thickened And natural water-soluble polymers such as saccharides. Among these, particularly preferable examples include polyvinyl alcohol, polyvinylpyrrolidones and copolymers containing them, gelatin, thickening polysaccharides (particularly celluloses) from the viewpoint of handling during production and film flexibility. Is mentioned. These water-soluble polymers may be used alone or in combination of two or more.

  Polyvinyl alcohol includes modified polyvinyl alcohol in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate. Examples of the modified polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, and vinyl alcohol polymers. Specific examples of polyvinyl alcohol include those described in [0075] to [0079] of International Publication No. 2013-054912.

  Moreover, you may use the hardening | curing agent for hardening polyvinyl alcohol. As an applicable curing agent, for example, boric acid and its salt are preferable. Specific examples of the other curing agent include those described in [0091] to [0096] of International Publication No. 2013-054912.

  In this embodiment, both the high refractive index layer and the low refractive index layer contain metal oxide particles. That is, the high refractive index layer includes first metal oxide particles in addition to the first water-soluble polymer, and the low refractive index layer includes the second metal in addition to the second water-soluble polymer. Contains oxide particles. Here, the first and second metal oxide particles may be the same or different.

  The metal oxide particles preferably have an average particle size of 100 nm or less, 1 to 50 nm, or 4 to 40 nm in order of preference. Here, the average particle diameter refers to the primary average particle diameter. When the metal oxide particles are coated (for example, silica-attached titanium oxide), the average particle diameter of the metal oxide particles is the matrix (in the case of silica-attached titanium oxide). , Titanium oxide before treatment).

  The content of the metal oxide particles in each refractive index layer is preferably 20 to 90% by mass, and more preferably 40 to 80% by mass with respect to the total mass of the refractive index layer.

  In the low refractive index layer, silicon dioxide (silica) is preferably used as the metal oxide particles, and acidic colloidal silica sol is particularly preferably used.

  As the metal oxide contained in the high refractive index layer, high refractive index metal oxide fine particles such as titanium and zirconia, that is, titanium oxide fine particles, Zirconium oxide fine particles are preferred, and rutile (tetragonal) titanium oxide fine particles are more preferred.

  Further, as the titanium oxide particles, those obtained by modifying the surface of the aqueous titanium oxide sol to stabilize the dispersion state may be used.

  As the titanium oxide sol, a titanium oxide sol particle described in JP-A-2008-266043 is used as a core, and a plurality of coating layers made of silicon, tin, and antimony hydrated oxides are provided around the titanium oxide sol particles. A transparent titanium oxide sol in which the sum oxide is the outermost coating layer may be used. Further, as the titanium oxide sol, acidic oxidation in which the particle surface is coated with colloidal particles of an acidic oxide using a titanium oxide-tin oxide-zirconium oxide-tungsten oxide composite colloidal particle as a core described in International Publication No. 2009/044879. It is also possible to use a material-coated titanium oxide-tin oxide-zirconium oxide-tungsten oxide composite colloidal particle, and a sol in which these composite colloidal particles are dispersed.

  In addition, as the metal oxide particles contained in the high refractive index layer, core-shell particles produced by a known method can be used. As a method for preparing the aqueous titanium oxide sol, any conventionally known method can be used. For example, JP-A-63-17221, JP-A-7-819, JP-A-9-165218, Reference can be made to the matters described in Kaihei 11-43327.

  Further, the titanium oxide particles may be coated with a silicon-containing hydrated oxide. Here, the “coating” means a state in which a silicon-containing hydrated oxide is attached to at least a part of the surface of the titanium oxide particles. That is, the surface of the titanium oxide particles used as the metal oxide particles may be completely covered with a silicon-containing hydrated oxide, and a part of the surface of the titanium oxide particles is a silicon-containing hydrated oxide. It may be coated. From the viewpoint that the refractive index of the coated titanium oxide particles is controlled by the coating amount of the silicon-containing hydrated oxide, it is preferable that a part of the surface of the titanium oxide particles is coated with the silicon-containing hydrated oxide. . The “silicon-containing hydrated oxide” in the present specification may be any of a hydrate of an inorganic silicon compound, a hydrolyzate and / or a condensate of an organosilicon compound, and preferably has a silanol group. In particular, as the silicon-containing hydrated oxide, silica hydrate is preferable. Titanium oxide coated with silica hydrate is hereinafter also referred to as silica-coated titanium oxide or silica-modified titanium oxide, referred to as silica-attached titanium oxide. ).

  The titanium oxide of the titanium oxide particles coated with the silicon-containing hydrated oxide may be a rutile type or an anatase type. The titanium oxide particles coated with a silicon-containing hydrated oxide are more preferably rutile-type titanium oxide particles coated with a silicon-containing hydrated oxide. This is because the rutile type titanium oxide particles have lower photocatalytic activity than the anatase type titanium oxide particles, and therefore the weather resistance of the high refractive index layer and the adjacent low refractive index layer is increased, and the refractive index is further increased. Because.

  The coating amount of the silicon-containing hydrated oxide is 2 to 30% by mass, preferably 3 to 10% by mass, more preferably 4 to 8% by mass. This is because when the coating amount is 30% by mass or less, a desired refractive index of the high refractive index layer can be obtained, and when the coating amount is 2% by mass or more, particles can be stably formed.

As a method of coating titanium oxide particles with a silicon-containing hydrated oxide, it can be produced by a conventionally known method. For example, JP-A-10-158015 (Si / Al hydration to rutile titanium oxide) Oxide treatment; a method of producing a titanium oxide sol in which a hydrous oxide of silicon and / or aluminum is deposited on the surface of titanium oxide after peptization in the alkaline region of the titanate cake), JP 2000-204301 A (A sol in which a rutile titanium oxide is coated with a complex oxide of Si and Zr and / or Al. Hydrothermal treatment), JP 2007-246351 (Oxidation obtained by peptizing hydrous titanium oxide) titanium to hydrosol, wherein ^R _{1 n SiX 4-n} (wherein ^{R 1} is C1-C8 alkyl group as a stabilizer, glycidyloxy substituted C1-C8 A compound having a complexing action with respect to an organoalkoxysilane or titanium oxide of an alkyl group or a C2-C8 alkenyl group, X is an alkoxy group, and n is 1 or 2. Sodium silicate or silica sol in an alkali region is added. The method described in, for example, a method for producing a titanium oxide hydrosol coated with a hydrous oxide of silicon by adding, pH adjusting, and aging to the above solution can be referred to.

  In addition, the high refractive index layer and / or the low refractive index layer may further include an ultraviolet absorber described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, Various surfactants such as anionic surfactant, cationic surfactant, nonionic surfactant, amphoteric surfactant, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, etc. PH adjusters, antifoaming agents, lubricants such as diethylene glycol, preservatives, antifungal agents, antistatic agents, matting agents, antioxidants, flame retardants, infrared absorbers, dyes, pigments, and various other known additives Etc. may be included.

<Infrared reflector>
The infrared shielding film of the present invention can be applied to a wide range of fields. That is, a preferred embodiment of the present invention is an infrared reflector in which an optical reflective film produced by the above production method is provided on at least one surface of a substrate.

  For example, film for window pasting such as heat ray reflecting film that gives heat ray reflection effect, film for agricultural greenhouses, etc. Etc., mainly for the purpose of improving the weather resistance. In particular, the optical reflective film according to the present invention is suitable for a member that is bonded to a substrate such as glass or a glass substitute resin directly or via an adhesive.

  Specific examples of the substrate include, for example, glass, polycarbonate resin, polysulfone resin, acrylic resin, polyolefin resin, polyether resin, polyester resin, polyamide resin, polysulfide resin, unsaturated polyester resin, epoxy resin, melamine resin, and phenol. Examples thereof include resins, diallyl phthalate resins, polyimide resins, urethane resins, polyvinyl acetate resins, polyvinyl alcohol resins, styrene resins, vinyl chloride resins, metal plates, and ceramics. The type of resin may be any of a thermoplastic resin, a thermosetting resin, and an ionizing radiation curable resin, and two or more of these may be used in combination. The substrate can be produced by a known method such as extrusion molding, calendar molding, injection molding, hollow molding, compression molding or the like. The thickness of the substrate is not particularly limited, but is usually 0.1 mm to 5 cm.

  The adhesive layer or adhesive layer that bonds the infrared shielding film and the substrate is preferably provided with the infrared shielding film on the sunlight (heat ray) incident surface side. In addition, it is preferable to sandwich the infrared shielding film between the window glass and the substrate because it can be sealed from surrounding gas such as moisture and has excellent durability. Even if the infrared shielding film according to the present invention is installed outdoors or outside a car (for external application), it is preferable because of environmental durability.

  The adhesive layer or pressure-sensitive adhesive layer that bonds the infrared shielding film and the substrate is preferably installed so that the infrared shielding film is on the sunlight (heat ray) incident surface side when pasted to a window glass or the like. Further, when the infrared shielding film is sandwiched between the window glass and the base material, it can be sealed from ambient gas such as moisture, which is preferable for durability. Even if the infrared shielding film of the present invention is installed outdoors or on the outside of a vehicle (for external application), it is preferable because of environmental durability.

  As an adhesive applicable to the present invention, an adhesive mainly composed of a photocurable or thermosetting resin can be used.

  The adhesive preferably has durability against ultraviolet rays, and is preferably an acrylic adhesive or a silicone adhesive. Furthermore, an acrylic adhesive is preferable from the viewpoint of adhesive properties and cost. In particular, since the peel strength can be easily controlled, a solvent system is preferable among the solvent system and the emulsion system in the acrylic adhesive. When a solution-polymerized thermoplastic resin is used as the acrylic solvent-based pressure-sensitive adhesive, known monomers can be used as the monomer.

  Polyvinyl butyral resin or ethylene-vinyl acetate copolymer resin may be used. Specifically, plastic polyvinyl butyral [manufactured by Sekisui Chemical Co., Ltd., Mitsubishi Monsanto Co., Ltd.], ethylene-vinyl acetate copolymer [manufactured by DuPont, Takeda Pharmaceutical Co., Ltd., duramin], modified ethylene-vinyl acetate copolymer [Mersen G manufactured by Tosoh Corporation]. In addition, you may mix | blend suitably an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, coloring, an adhesion regulator, etc. in an adhesion layer or an adhesion layer.

<Method for reducing haze of functional film>
In the present invention, a coating film is formed on the substrate by simultaneously applying two or more coating liquids on the substrate, thereby forming a coating film; and drying the coating film. Wherein the haze of the functional film is reduced, and before the coating film forming step, at least one of the two or more coating liquids that becomes an adjacent layer When the dissolved oxygen concentration (DO) is measured and the dissolved oxygen concentration (DO) is higher than the saturated dissolved oxygen concentration (SDO) at the highest temperature of the coating film reached in the drying step, the saturated dissolved oxygen concentration ( There is also provided a method for reducing the haze of a functional film, which has a degassing treatment so as to be lower than SDO).

  The specific description of the method for reducing the haze of the functional film is omitted because the above description is also valid.

  The haze of the functional film is preferably 2.0% or less, more preferably 1.5% or less, and further preferably 1.0% or less. However, in reality, it is often 0.5% or more. Thus, in the functional optical film, the haze is often designed by use and grade within a range of 0.5 to 2.0%.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

  First, the overall flow will be described. Prepare the raw materials that will be the three coating liquids of the coating solution for the lowest refractive index layer, the coating liquid for the low refractive index layer, and the coating liquid for the high refractive index layer, by adding them to separate preparation kettles. Perform the process. Thereafter, the prepared three kinds of coating liquids are respectively passed through a dispersion process and a supply process, and the three kinds of coating liquids are merged in the coating process to perform simultaneous multilayer coating.

  In simultaneous multi-layer coating, an infrared shielding film as a functional film is produced by alternately applying a total of nine layers of the prepared three coating liquids onto a substrate using a slide hopper coating apparatus.

  Hereinafter, description will be made with reference to FIG. 1 as appropriate.

(Preparation process)
First, the preparation process will be described. The preparation of three coating solutions is shown below.

(1) Preparation of coating liquid for lowermost layer low refractive index layer The following constituent materials are added to coating liquid preparation pot 101 in this order at 40 ° C., mixed, and then finished to 1000 parts with pure water. Then, a coating solution for the lower refractive index layer of the lowermost layer was prepared.

-10% by weight of colloidal silica (Snowtex OXS, average primary particle size: 4-6 nm, manufactured by Nissan Chemical Industries, Ltd.) 320 parts;
-58 parts of a 3% by weight boric acid aqueous solution;
・ 182 parts of pure water;
4 mass% polyvinyl alcohol (4 mass% aqueous solution, PVA-235; polymerization degree: 3500; saponification degree: 88 mol%; manufactured by Kuraray Co., Ltd.) 360 parts;
-5 parts by weight of a surfactant (5% by weight aqueous solution, Amphital 20HD; manufactured by Kao Corporation) 3.0 parts.

(2) Preparation of coating solution for low refractive index layer The following constituent materials were added to and mixed with coating solution preparation kettle 101 different from the above in this order at 40 ° C. The coating solution for the low refractive index layer was prepared.

-10 mass% colloidal silica (Snowtex OXS, average primary particle size: 4-6 nm, manufactured by Nissan Chemical Industries, Ltd.) 430 parts;
-25 parts of a 3% by weight boric acid aqueous solution;
-130 parts of pure water;
-8% by weight of polyvinyl alcohol (8% by weight aqueous solution, JP45; degree of polymerization: 4500; degree of saponification: 88 mol%; manufactured by Nihon Acetate / Poval) 300 parts;
-7 parts by weight of a 5% by weight surfactant (5% by weight aqueous solution, Amphital 20HD; manufactured by Kao Corporation).

(3) Preparation of coating solution for high refractive index layer A coating solution for high refractive index layer was prepared according to the following procedure.

<Preparation of silica-modified titanium oxide particle dispersion>
First, a dispersion of silica-modified titanium oxide particles was prepared according to the following method, and a solvent or the like was added thereto.

  A dispersion of silica-modified titanium oxide particles was prepared as follows.

The titanium sulfate aqueous solution was thermally hydrolyzed by a known method to obtain titanium oxide hydrate. The obtained titanium oxide hydrate was suspended in water to obtain 10 L of an aqueous suspension of titanium oxide hydrate (TiO ₂ concentration: 100 g / L). To this, 30 L of an aqueous sodium hydroxide solution (concentration 10 mol / L) was added with stirring, the temperature was raised to 90 ° C., and the mixture was aged for 5 hours. The obtained solution was neutralized with hydrochloric acid, filtered and washed with water to obtain a base-treated titanium compound.

Next, the base-treated titanium compound was suspended in pure water and stirred so that the TiO ₂ concentration was 20 g / L. Under stirring, it was added citric acid in an amount of 0.4 mol% with respect to TiO ₂ weight. The temperature was raised to 95 ° C., concentrated hydrochloric acid was added so that the hydrochloric acid concentration was 30 g / L, and the solution temperature was maintained, followed by stirring for 3 hours. Here, when the pH and zeta potential of the obtained mixed solution were measured, the pH at 25 ° C. was 1.4, and the zeta potential was +40 mV. Further, when the particle size was measured by Zetasizer Nano (manufactured by Malvern), the volume average particle size was 35 nm and the monodispersity was 16%.

  1 kg of pure water was added to 1 kg of a 20.0 mass% titanium oxide sol aqueous dispersion containing rutile-type titanium oxide particles to prepare a 10.0 mass% titanium oxide sol aqueous dispersion.

2 kg of pure water was added to 0.5 kg of the 10.0 mass% titanium oxide sol aqueous dispersion, followed by heating to 90 ° C. Thereafter, 1.3 kg of an aqueous silicic acid solution having a SiO ₂ concentration of 2.0 mass% was gradually added. The obtained dispersion is subjected to a heat treatment at 175 ° C. for 18 hours in an autoclave, and further concentrated to thereby contain 20% by mass of silica-modified titanium oxide particles containing titanium oxide having a rutile structure coated with SiO _2. A dispersion (sol aqueous dispersion) was obtained. The silica modification rate at this time was 4 mass%.

<Preparation of coating solution>
The following constituent materials are sequentially added to the above-prepared sol dispersion of silica-modified titanium oxide particles at 40 ° C. in the coating solution preparation kettle 101 different from the above, and finally finished to 1000 parts with pure water. A coating solution for the refractive index layer was prepared.

-360 parts by weight of a sol aqueous dispersion of 20.0 mass% silica-modified titanium oxide particles;
140 parts of 1.92% by weight citric acid aqueous solution;
・ 190 parts pure water;
-8% by mass of ethylene-modified polyvinyl alcohol (RS-2117, polymerization degree: 1700, saponification degree: 99 mol%, manufactured by Kuraray Co., Ltd.) 300 parts;
-A 5% by weight aqueous surfactant solution (Amphithal HD, manufactured by Kao Corporation) 3.6 parts.

  As described above, three types of coating liquids, that is, the coating liquid for the lowest refractive index layer, the coating liquid for the low refractive index layer, and the coating liquid for the high refractive index layer were prepared in the coating liquid preparation pot 101.

<Transfer to coating solution storage>
Transfer to the coating liquid storage tank 105 is performed by supplying a flow rate of 10 L / min using a gear pump (Iwaki Chemical Gear Pump GX-25) as the liquid feeding device 102, and using a milder emulsifying and dispersing device (Daiyoyo) as the dispersing device 103. Each of the coating liquids was transferred to the coating liquid storage tank 105 through the filtration device 104 while dispersing the coating liquid using a Kinder milder dispersion machine MDN306, controlled at a rotational speed of 3000 rpm. As the filtration device 104, a filter cartridge in which a 3M surface type filter BTJ series (filtration accuracy: 10 μm, 10 inch size) was used was used.

(Dispersion process)
<Deaeration process>
The coating liquid sent to the coating liquid storage tank 105 is further returned to the coating liquid storage tank 105 by passing through the circulation path R1 through the liquid feeding device 106, the dispersion device 107, the filtration device 108, and the deaeration device 118. A coating solution can be prepared. In the present invention, a deaeration device is inserted in the circulation path, and the deaeration degree is changed by adjusting the circulation time, and the effect on the performance (haze) is observed and compared.

  The liquid feeding device 106 is supplied with a flow rate of 10 L / min using a gear pump (Iwaki Chemical Gear Pump GX-25) in the same manner as in the preparation step, and the dispersing device 107 is also a milder emulsifying and dispersing device (Milder dispersing machine MDN306 manufactured by Taiyo Kiko Co., Ltd.). , Controlled at a rotational speed of 3000 rpm to 4000 rpm) and circulated while adjusting the viscosity of the coating solution. At this time, the rotation speed of the dispersion device 107 is adjusted such that the liquid temperature is 40 ° C., the viscosity of the lower refractive index layer coating solution is 10 to 15 mPa · s, and the viscosity of the low refractive index layer coating solution is The viscosity of the coating liquid for 150 to 200 mPa · s and the high refractive index layer was adjusted to 10 to 20 mPa · s. The viscosity was measured using a rotary viscometer (Brookfield Digital Viscometer DV-E).

  The filter device 108 used was a filter cartridge in which a 3M surface type filter BTJ series (filtration accuracy 1 μm, 10 inch size) was inserted.

Two degassing membrane modules manufactured by Polypore Co., Ltd., Superphobic 4 × 13 (membrane area 8 m ² ), are installed in parallel in the degassing device 118 that performs the degassing process, and the liquid is passed at a flow rate of 10 L / min. And deaerated.

  The deaeration membrane was fixed at a reduced pressure of 50 Torr.

  The degree of deaeration in the case of the coating solution for the low refractive index layer and the coating solution for the high refractive index layer is two types of circulation times of 100 minutes and 200 minutes, and the case where no deaeration is performed by removing the deaeration device. Three types of coating liquids with different degrees of deaeration were prepared.

  For the coating solution for the lower refractive index layer in the lowermost layer, two types of coating solutions with a circulation time of 100 minutes and without deaeration by removing the deaeration device (difference in dissolved oxygen concentration) are prepared. did.

  The dissolved oxygen concentration of each coating solution adjusted as described above is shown in the table below.

  The dissolved oxygen concentration (DO value) of the coating solution is measured by sampling about 500 cc of the coating solution from the coating solution storage tank 105, and adjusting the solution temperature to the temperature at the time of coating. The DO meter manufactured by Iijima Electronics Co., Ltd. This was performed by measuring the dissolved oxygen concentration [mg / L] using (B-505).

(Supply process)
Subsequently, the coating liquid was supplied to the coating apparatus 112 through a supply process. The supply process mainly includes a branch device (not shown), a liquid feeding device 109, a flow meter 110, and a filtration device 111. The branching device is a branching path for supplying the liquid by dividing the coating liquid from one path into a plurality of paths. In the present invention, there are four coating liquids for the low refractive index layer. Since there are also four coating solutions for branching and high refractive index layers, a branching path that can branch into four is used. The liquid feeding device 109 uses a gear pump (chemical gear pump GX-15 made by Iwaki) as the lowermost refractive index layer coating liquid and the lower refractive index layer coating liquid, and a diaphragm pump as the high refractive index layer coating liquid. The coating solution was supplied to the coating device 112 using (made by Takumina).

(Coating process)
The coating process mainly includes a coating device 112, a set device 113, and a drying device 114.

<Coating film formation process>
The coating device used in the coating film forming process uses a slide hopper coating device, and while keeping the coating solution temperature at 40 ° C., the lower refractive index layer coating solution for the lowermost layer is placed in the lowermost layer, and the high refractive index thereon. An infrared shielding film was prepared by simultaneously applying multiple layers at a coating speed of 100 m / min on all nine layers so that a high refractive index layer and a low refractive index layer were alternated, and a low refractive index layer was formed thereon. .

  The coating flow rate was adjusted so that the thickness of the coating after drying was 600 nm for the lowest refractive index layer for the lowermost layer, 160 nm for the low refractive index layer, and 140 nm for the high refractive index layer. As the substrate, a polyethylene terephthalate film (A4300 manufactured by Toyobo Co., Ltd .: double-sided easy adhesion layer) having a thickness of 50 μm was used.

  The set device was under the condition of a dry bulb temperature of 15 ° C.

<Drying process>
The drying device 114 has a plurality of zones, and the drying conditions and temperature conditions can be changed in each zone. However, in order to easily understand the influence of the temperature, all the zones are set to the same temperature, and the film surface temperature near each zone outlet is set. It measured using the non-contact-type thermometer (Infrared radiation thermometer IT2-50 by Keyence Corporation). At this time, an infrared moisture meter was used in advance to grasp the zone at the end of drying where there was no change in the amount of moisture in the film, and the zone up to that zone was used as the measurement object.

  In this example, in order to grasp the point where the maximum temperature is reached, a thermometer for measuring the film surface temperature is installed near the exit of each zone in the drying apparatus so as to measure the maximum temperature. There is no heating zone after the drying device, and the inside of the drying device is set to the maximum film surface temperature.

  The saturated dissolved oxygen concentration with respect to the film surface temperature was calculated as follows. In this example, since the solvent is only water and the concentration is very thin, the saturated dissolved oxygen concentration of the coating solution (coating film) is considered to be substantially the same as the saturated dissolved oxygen concentration of the solvent water (distilled water), The saturated dissolved oxygen concentration with respect to temperature was calculated as shown in the table below. The table below shows the saturated dissolved oxygen concentration with respect to the water temperature in distilled water and 1 atm environment, and for the saturated dissolved oxygen concentration of 40 ° C. or higher, the Trusdale equation (GA Trusdale, et.al. Chem., 5, 53 (1955) When calculating the saturated dissolved oxygen concentration from the temperature, if the temperature is in the middle of the values in the table, the saturated dissolved oxygen concentration was calculated by interpolation. Therefore, for example, in the case of 35 ° C., the values of 30 ° C. and 40 ° C. are interpolated, and the saturated dissolved oxygen concentration is calculated as 7.06 mg / L, and in the case of 48.5 ° C., it is calculated as 5.81 g / L. did.

  In addition, when a solvent is other than water, it can apply similarly by measuring the saturated dissolved oxygen concentration with respect to the temperature in the solvent beforehand. Saturated dissolved oxygen concentration should be measured in the same manner using a DO meter after sufficiently supplying oxygen while bubbling into the solvent solution and bringing oxygen into contact until the dissolved amount of oxygen is saturated. Can be obtained at

<Result>
The results are shown in Table 3 below.

<Haze evaluation method>
The haze value was evaluated using the haze meter (NDH 2000 manufactured by Nippon Denshoku Industries Co., Ltd.), measuring five points of the measurement sample, and evaluating the average value according to the following rank.

◎ 1.2% or less ○ 1.2% or more 1.5% or less △ 1.5% or more 2.0% or less × 2.0% or more <Discussion>
From the present inventions 1, 3, and 4, it was confirmed that the haze was good when all three types of coating liquids had a dissolved oxygen concentration lower than the saturated dissolved oxygen concentration with respect to the maximum temperature of the coating film surface. Further, from the present inventions 2, 5, 6, and 7, if at least one of the three types of coating solutions has a dissolved oxygen concentration lower than the saturated dissolved oxygen concentration with respect to the maximum temperature of the coating surface, then haze Was confirmed to be good. On the other hand, in Comparative Examples 1-5, even if the coating film temperature changes or the dissolved oxygen concentration of the coating solution changes, the dissolved oxygen concentration of all the liquids is higher than the saturated dissolved oxygen concentration with respect to the maximum temperature of the coating film surface. It was found that haze deteriorates when the value becomes high. Therefore, in order to improve the haze, it was found that at least one side of the layered coating solution needs to have a dissolved oxygen concentration lower than the saturated dissolved oxygen concentration during the drying process.

1 Infrared shielding film manufacturing system,
101 preparation kettle,
102, 106, 109, liquid feeding device,
103, 107 dispersion device,
104, 108, 111 filtration device,
118 deaerator,
105 Storage pot,
110 flow meter,
112 coating device,
113 set device,
114 drying equipment,
121 sampling container,
123 pressure gauge,
L0 transport path,
L1 supply path,
R1 circulation path,
9 Deaeration device using hollow fiber membrane,
91 Deaeration module 91,
92 hollow fiber membrane,
21a, 21c liquid feeding pipe,
VP vacuum pump,
1a Slide type coater,
2 Back roll,
3 belt-like support,
4 Coating liquid supply system,
5a coating layer,
6 decompression chamber,
11 Dice,
12 slits,
13 Lip part,
14 pockets,
15 slide surface,
16 beads,
17 Edge guide,
41 Adjustment hook,
42 Liquid feed pump,
43 supply pipe,
61 Suction tube.

Claims (10)

A coating film forming step of laminating a coating film on the substrate by simultaneously applying two or more coating solutions on the substrate, and drying the coating film, and a drying step. A method for producing a conductive film,
Before the coating film forming step, at least one dissolved oxygen concentration (DO) that becomes an adjacent layer among the two or more coating solutions is saturated dissolved at the maximum temperature of the coating film that is reached in the drying step. The manufacturing method of a functional film which further has a deaeration process which deaerates so that it may become below oxygen concentration (SDO).   The manufacturing method of Claim 1 which performs the said deaeration process to all the coating liquids apply | coated simultaneously.   The manufacturing method of Claim 1 or 2 whose at least 1 viscosity of the said coating liquid is 100 cP or more.   The manufacturing method according to claim 1, wherein at least one of the deaeration treatments is performed using a deaeration membrane.   The manufacturing method of any one of Claims 1-4 with which the said deaeration process is implemented in the circulation path | route which circulates the said coating liquid.   The manufacturing method according to claim 4 or 5, wherein the degassing membrane is used by being arranged in two or more units in parallel.   The manufacturing method of any one of Claims 1-6 which measures the dissolved oxygen concentration (DO) of the said coating liquid, and changes the conditions of the said deaeration process according to the result.   The manufacturing method of any one of Claims 1-7 whose said functional film is an infrared shielding film.   An infrared reflector comprising the infrared shielding film according to claim 8 provided on at least one surface of a substrate. By simultaneously coating two or more coating liquids on a base material to form a coating film on the base material, forming a coating film; drying the coating film, and drying process. A method for reducing the haze of a functional film produced,
Prior to the coating film forming step, at least one dissolved oxygen concentration (DO), which becomes an adjacent layer among the two or more coating solutions, is measured, and the dissolved oxygen concentration (DO) is the drying step. A functional film having a degassing treatment so as to be lower than the saturated dissolved oxygen concentration (SDO) when it is higher than the saturated dissolved oxygen concentration (SDO) at the maximum temperature of the coating film reached at A method of reducing haze.