JP5000240B2 - Method for producing photocatalytic film sheet - Google Patents

Description

The present invention relates to a manufacturing method of a photocatalyst film sheet.

Recently, a photocatalytic action containing a photocatalytic material such as titania (TiO ₂ ) has attracted attention. As a mechanism of photocatalysis, active oxygen is formed from water or oxygen in the atmosphere when titania captures ultraviolet light. This activity has the ability to degrade organic substances and microorganisms present near the surface of the titania-coated material. As a result, the surface covered with the photocatalyst particles has antibacterial properties or bactericidal properties (see, for example, Patent Document 1).

Since active oxygen has an affinity for decomposing organic substances, it can also be used as a deodorant. By coating the base paper with an aqueous dispersion containing photocatalyst particles and a binder, deodorized paper suitable for use in an air cleaner or other gas stream can be produced (see Patent Document 2).
JP 11-47610 A JP-A-11-279446

  The photocatalyst layer as described above is conventionally formed in a single sheet. For this reason, it has been difficult to reduce product prices due to mass production.

Therefore, in view of the above problems, the present invention provides a method for producing a photocatalytic film sheet capable of mass production.

In the present invention, a primer layer is coated on a surface of a long substrate to travel with a thickness of 0.1 to 0.2 μm by a chamber gravure coating device or a capillary coating device. Next, hot air is applied to the traveling base material by a counter flow method, the primer layer of the base material is dried, and then hot air is alternately applied to the traveling base material from above and below, and the base material is floated. Next, the primer layer is dried, and then the protective layer is applied to the dried primer layer of the traveling substrate by a reverse coating apparatus or a lip coater coating apparatus with a thickness of 1 to 2 μm. Next, hot air is applied to the traveling substrate by a counter flow method, the protective layer of the substrate is dried, and then hot air is alternately applied from above and below to the traveling substrate, Base material The protective layer is dried, and then a photocatalyst layer is added to the dried protective layer of the traveling substrate by a chamber gravure coating device, a die coating device, or a capillary coating device. Coating is carried out with a thickness of 1 to 0.2 μm, and then hot air is applied to the traveling substrate by a counter flow method to dry the photocatalyst layer of the substrate, and then the traveling substrate is moved up and down. Then, hot air is alternately applied to dry the photocatalyst layer of the substrate by a floating method.

According to the present invention, mass production of a photocatalytic film sheet can be performed.

  Hereinafter, the photocatalyst film sheet 10 and the sheet manufacturing apparatus 20 according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
A photocatalytic film sheet 10 and a sheet manufacturing apparatus 20 according to the first embodiment will be described with reference to FIGS.

(1) Configuration of Photocatalytic Film Sheet 10 The configuration of the photocatalytic film sheet 10 will be described based on FIG.

  In the photocatalytic film sheet 10, a primer layer 14 is laminated on a substrate 12, a protective layer 16 is laminated on the primer layer 14, and a photocatalytic layer 18 is laminated on the protective layer 16.

  The substrate 12 is made of, for example, biaxially stretched polypropylene.

  The first primer layer 14 is laminated for the purpose of improving the surface smoothness with respect to a substrate having poor surface smoothness of the substrate 12 such as biaxially stretched polypropylene. However, the primer layer 14 may be omitted as shown in FIG. 2 for the base 12 having good surface smoothness such as polyethylene terephthalate. This primer layer 14 uses a silica-based solution.

  The second protective layer 16 improves the adhesion between the surface of the primer layer 14 or the base material 12 which is an organic substance and the photocatalyst layer 18 which is an inorganic substance, and plays a role in the decomposition protection of the base material 12 side by the photocatalytic function. Yes. As the protective layer 16, an Si binder or a Ti binder having no photocatalytic function is used as a component, and an inorganic binder is used.

  The third photocatalyst layer is made of titanium oxide.

(2) Structure of Sheet Manufacturing Device 20 A sheet manufacturing device 20 for manufacturing the photocatalytic film sheet 10 as described above will be described with reference to FIGS.

  The sheet manufacturing apparatus 20 includes a wet coating apparatus 22, a first drying apparatus 24, a second drying apparatus 26, a third drying apparatus 28, and a winding apparatus 30.

  The wet coating apparatus 22 unwinds the wound base material 12 from the unwinding roll 32 and performs coating. As shown in FIGS. 4 to 7, four types of wet coating apparatuses are suitable for this coating. The first is a reverse coating device 34, the second is a die coating device 36, the third is a chamber gravure coating device 38, and the fourth is a capillary coating device 40. Each of these coating apparatuses 34 to 40 will be described in detail later.

  In the first drying device 24, a plurality of nozzles 44 are arranged at predetermined intervals below the horizontal conveyance path inside the first heating chamber 43, and drying is performed by applying hot air from these nozzles 44 to the base material 12 that travels upward. Do. The reason why the hot air is applied to the base material 12 by the counter flow method is to dry slowly immediately after coating, and the wind speed of the hot air is 1 to 3 m / sec.

  In the second drying device 26, a plurality of upper nozzles 46 and a plurality of lower nozzles 48 are arranged at predetermined intervals above and below a horizontal conveyance path inside the second heating chamber 45, and upper and lower nozzles 46, 48 are arranged in a staggered manner. Has been. Therefore, it becomes a floating system in which hot air is alternately applied from above and below to the base material 12 traveling on the conveyance path. The reason why the floating method is used in this way is to dry the substrate 12 at a high rate.

  Similarly to the second drying device 26, the third drying device 28 is also provided with a plurality of upper nozzles 50 and a plurality of lower nozzles 52 on the conveyance path inside the heating chamber 49, respectively, so that the substrate 12 can be moved at a high rate by a floating method. Dry with.

(3) Structure of reverse type coating apparatus 34 The reverse type coating apparatus 34 is demonstrated based on FIG.

  The reverse coating apparatus 34 is provided with a die 56 below the backup roll 54 and a roll 58 on the side of the backup roll 54.

  The substrate 12 is caused to travel by the backup roll 54, the coating liquid for forming the protective layer 16 is applied from the die 56, the unnecessary coating liquid is scraped off by the roll 58, and the coating liquid on the surface of the roll 58 is removed. Further, it is scraped off to the collection tray 61 by the scraping piece 60. In this case, the film thickness is determined by the gap between the roll 58 and the backup roll 54.

(4) Configuration of Die Type Coating Device 36 Next, the die type coating device 36 will be described with reference to FIG.

  The substrate 12 runs on four guide rolls 62 to 68, and the die 70 is installed between the guide rolls 64 and 66. When the substrate 12 passes between the guide roll 64 and the guide roll 66, a coating liquid for forming the primer layer 14 or the photocatalyst layer 18 is applied by the die 70.

(5) Configuration of Chamber Gravure Coating Device 38 Next, the chamber gravure coating device 38 will be described with reference to FIG.

(5-1) Configuration The configuration of the chamber gravure coating device 38 will be described.

  In the chamber gravure coating device 38, guide rolls 74 and 76 are respectively arranged upstream and downstream of the gravure roll 72, and a liquid reservoir 78 for storing a coating liquid is provided below the gravure roll 72.

  A coating liquid injection port 80 and a spout 82 are provided on the bottom surface of the liquid reservoir 78, and a partition wall 84 is provided between the injection port 80 and the spout 82. A liquid reservoir 86 and a second liquid reservoir 88 are divided. There is a slight gap between the upper end of the partition wall 84 and the gravure roll 72.

  A first closing piece 90 is provided on the upstream side of the first liquid reservoir 86 and is substantially closed from the outside. That is, the tip of the first closing piece 90 hits the gravure roll 72 and closes the first liquid reservoir 86 substantially.

  Similarly, a second closing piece 92 is provided on the downstream side of the second liquid reservoir 88, and the tip of the second closing piece 92 hits the gravure roll 72 to close the second liquid reservoir 88.

  The diameter of the gravure roll 72 is 40 to 100 mm, and preferably 62 mm. The gravure roll 72 has 100 to 200 grooves, preferably 150 grooves per inch, and the depth of the grooves is 20 to 60 μm, preferably 45 μm. Thereby, the photocatalyst layer 18 having a thickness of 0.1 to 0.2 μm can be applied smoothly.

  The insides of the first liquid reservoir 86 and the second liquid reservoir 88 are mirror-finished or fluorine processed so that the coating liquid for applying the photocatalyst layer 18 does not adhere to the inside.

(5-2) Coating method Coating with a coating liquid by the chamber gravure coating device 38 will be described.

  In the case of coating, the coating liquid is injected from the injection port 80 at a constant pressure, and the gravure roll 72 is rotated in the clockwise direction in FIG. On the other hand, the base 12 is run at 20 m / min. Then, the coating liquid is applied to the groove and the surface of the gravure roll 72 by the gap portion between the tip end of the partition wall 84 and the gravure roll 72, and applied to the substrate 12 through the second closing piece 92. Then, the surplus coating liquid reaches the second liquid reservoir 88 and is carried out from the spout 82 to the outside.

(6) Configuration of Capillary Coating Device 40 Next, the capillary coating device 40 will be described with reference to FIG.

  The capillary coating device 40 includes a backup roll 94, a nozzle 96 disposed below the backup roll 94, and a coating liquid supply unit 98. The nozzle 96 is disposed below the backup roll 94 and has a slit 100 that is so thin that capillary action occurs along the width direction of the substrate 12. The coating liquid is supplied from the coating liquid supply unit 98 to the liquid reservoir 102 below the slit 100.

  When performing coating, the coating liquid tank 98 is moved up and down to adjust its height, and the amount of coating liquid discharged from the upper end of the slit 100 is adjusted by the pressure of the liquid height and the capillary phenomenon. Then, the coating liquid is applied to the base material 12 traveling on the backup roll 94.

(9) Coating method of each layer Each coating apparatus 34-40 as mentioned above is attached to the sheet manufacturing apparatus 20 alternately, and the primer layer 14, the protective layer 16, and the photocatalyst layer 18 are laminated | stacked in order, respectively.

  That is, as the first step, the substrate 12 is wound around the unwinding roll 32, and this is pulled out at a traveling speed of 10 to 30 m / min (preferably 20 m / min), and a wet coating apparatus. The primer layer 14 is applied by 22. Next, each drying is performed at 100 ° C. to 150 ° C. (preferably 120 ° C.) for 10 to 40 seconds (preferably 20 to 25 seconds) by the first drying device 24, the second drying device 26, and the third drying device 28. It heat-processes with the apparatus 24, 26, 28, is dried, and is wound up by the winding roll 31 of the winding apparatus 30. FIG.

  As the second step, the base material 12 on which the primer layer 14 is laminated is wound around an unwinding roll 32, which is pulled out and coated with a protective layer 16 by a wet coating device 22. 1 Drying device 24, second drying device 26, and third drying device 28 are heat-treated at 40 ° C. to 80 ° C. (preferably 60 ° C.) for a total of 3 to 8 hours (preferably 5 hours), dried and wound up It winds up on the winding roll 31 of the apparatus 30.

  As the third step, the base material 12 on which the primer layer 14 and the protective layer 16 are laminated is wound around an unwinding roll 32, and this travels at 10 to 30 m / min (preferably 20 m / min). The photocatalyst layer 18 is coated by the wet coating device 22 with a speed, and the first drying device 24, the second drying device 26, and the third drying device 28 are used at 100 ° C. to 150 ° C. (preferably 120 ° C.). For 10 to 40 seconds (preferably 20 to 25 seconds), each of the drying devices 24, 26, and 28 is dried by heat treatment, wound on a winding roll 31 of a winding device 30, and the photocatalytic film sheet 10 is Complete.

  The first primer layer 14 needs to be applied with high accuracy since it needs to be applied with an error of ± 2% at 0.1 to 0.2 μm. Therefore, the wet coating apparatus 22 is coated using the chamber gravure coating apparatus 38 or the capillary coating apparatus 40 described above.

  Since the second protective layer 16 is applied with an error of ± 2% at 1 to 2 μm, the wet type coating device 22 is a reverse type coating device 34 or a conventional lip coater type coating device. Apply using.

  Since the third photocatalyst layer 18 needs to be applied with an error of ± 2% at 0.1 to 0.2 μm, the wet coating device 22 may be a chamber gravure coating device 38 or a die type. Coating is performed using the coating device 36 or the capillary coating device 40.

(10) Effect As described above, since the manufacturing method of the photocatalytic film sheet 10 of the present embodiment is manufactured using the sheet manufacturing apparatus 20 having the wet coating apparatus 22, the initial cost and The running cost can be greatly reduced, and the product can be sold at a low price. For this reason, the photocatalytic functions such as dirt prevention, antibacterial effect, and deodorizing effect can be exerted in various fields such as food packaging, wallpaper, and kitchen use.

(Second Embodiment)
The difference between the present embodiment and the first embodiment is that the substrate 12 has light resistance.

  That is, the base material 12 such as a PET film is a film that is excellent in price performance and easy to handle, but has a disadvantage that it is yellowed due to a change with time when exposed to ultraviolet rays.

  Therefore, light resistance treatment is performed on one side or both sides of the substrate 12. In the case of single-side treatment, the photocatalyst layer 18 takes into consideration the surface that is exposed to ultraviolet rays and the surface that exhibits the photocatalytic function. For example, when the photocatalyst film sheet 10 is attached to the outside of the window glass, the photocatalyst layer 18 When the layer 18 or the like is applied and the photocatalyst film sheet 10 is attached to the inside of the window glass for the purpose of deodorization or the like, the photocatalyst layer 18 or the like is applied to the side opposite to the surface subjected to the light resistance treatment.

(Third embodiment)
The difference between the third embodiment and the first embodiment is that an ultraviolet ray cut function is provided.

  The photocatalytic film sheet 10 must have a protective layer 16 for the purpose of improving the adhesion between the organic material as the base material 12 and the inorganic material as the titanium oxide film and protecting the film from the photocatalytic function of organic matter decomposition. This protective layer 16 is provided with an ultraviolet cut function.

  Specifically, a thin film mainly composed of rutile-type titanium oxide having no photocatalytic function is used. Thereby, it can have an ultraviolet cut function without a photocatalytic function. And the photocatalyst film sheet 10 whole can be provided with both functions of a photocatalyst function and an ultraviolet cut function.

  The photocatalyst film sheet 10 having such an ultraviolet cut function can decompose ethylene generated from vegetables and the like by the photocatalyst function, thereby extending the shelf life of food, preventing discoloration by ultraviolet rays, preventing indoor sunburn and dirt, and deodorizing It is effective for etc.

It is a longitudinal cross-sectional view of the photocatalyst film sheet which shows one Embodiment of this invention. It is a longitudinal section of the photocatalyst film sheet of a modification similarly. It is a side view of a sheet manufacturing apparatus. It is explanatory drawing of a reverse type coating apparatus. It is explanatory drawing of a die-type coating apparatus. It is explanatory drawing of a chamber gravure type coating apparatus. It is explanatory drawing of the coating apparatus of a capillary system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Photocatalyst film sheet 12 Base material 14 Primer layer 16 Protective layer 18 Photocatalyst layer 20 Sheet manufacturing apparatus 22 Coating apparatus 24 1st drying apparatus 26 2nd drying apparatus 28 3rd drying apparatus

Claims (3)

The primer layer is applied to the surface of the long substrate to travel with a thickness of 0.1 to 0.2 μm using a chamber gravure coating device or a capillary coating device,
Next, hot air is applied to the traveling base material by a counterflow method, and the primer layer of the base material is dried,
Next, hot air is alternately applied to the traveling base material from above and below, the primer layer of the base material is dried by a floating method,
Next, a protective layer is applied to the dried primer layer of the traveling substrate by a reverse coating apparatus or a lip coater coating apparatus with a thickness of 1 to 2 μm ,
Next, hot air is applied to the traveling base material by a counterflow method to dry the protective layer of the base material,
Next, hot air is alternately applied to the traveling base material from above and below, and the protective layer of the base material is dried by a floating method,
Next, on the dried protective layer of the substrate, the photocatalyst layer is 0.1 to 0.2 μm thick by a chamber gravure coating device, a die coating device, or a capillary coating device. Coated with
Next, hot air is applied to the traveling base material in a counterflow manner, and the photocatalytic layer of the base material is dried,
Next, hot air is alternately applied to the traveling base material from above and below, and the photocatalytic layer of the base material is dried by a floating method.
The manufacturing method of the photocatalyst film sheet characterized by the above-mentioned. Light-proofing the substrate;
The method for producing a photocatalytic film sheet according to claim 1. The protective layer is mainly composed of titanium oxide,
The method for producing a photocatalytic film sheet according to claim 1 or 2.

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