JP2019089068A - Method for bonding photocatalytic film - Google Patents

Abstract

To stabilize the bonding strength of photocatalytic film bonding performed using a fluororesin film for a longer time than before.SOLUTION: The edges of photocatalytic films 1 having a photocatalytic layer 13 made of FEP and photocatalytic powder on one or both sides of a fluororesin film made of PTFE covering a substrate made of glass fiber are heat-welded and bonded each other through a fluororesin film 2 sandwiched between the overlaid edges of the photocatalytic film 1. On one side of the fluorine resin film 2, there is provided a carbonate-containing layer 22 in which carbonate powder having a melting point of 330°C or more and a water solubility of 2 g/100 g is mixed with FEP, and the carbonate-containing layer 22 is abutted with the photocatalytic layer 13 during bonding.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique for bonding photocatalytic films to each other.

  For example, a photocatalytic layer, which is a layer of a fluorocarbon resin in which a photocatalytic powder having a photooxidative action such as titanium dioxide is mixed in a film material used as a building material for constructing a film structure, There is a photocatalytic film having on the surface of The photocatalyst powder in the photocatalyst layer receives light such as sunlight to exhibit a photo-oxidizing action, and exhibits excellent functions such as antifouling, deodorizing and anti-bacteria based on the oxidizing action.

By the way, when the film structure is large to some extent, it is necessary to connect the photocatalyst film to another photocatalyst film.
Bonding of the photocatalytic film is generally performed by overlapping the edges of the photocatalytic film with a predetermined width and heating and welding the overlapped portion. Such welding is carried out by heating at a temperature higher than the melting point of the fluorocarbon resin and pressurizing the overlapping portion of the adjacent photocatalytic films, often with an appropriate pressure.

  However, even when such a welding method is used, the peel strength of the joint may not be sufficient. In order to eliminate such insufficient peeling strength of the bonding portion, a thin fluorine resin film, which is made of a fluorine resin having a relatively low melting point, which is different from the photocatalytic film to be bonded, is easier to melt, A technique is used in which the peel strength of the bonded portion of the photocatalyst film is increased by sandwiching and heating between the portions to be overlapped. In this technique, the melted surface portion of the fluorine resin film functions like an adhesive, so that the peel strength of the bonded portion of the photocatalyst film is improved.

By the way, even if it is a case where the above-mentioned fluororesin film is used for joining of a photocatalyst film, the exfoliation strength of a joined part may deteriorate. This possibility generally occurs not only when the edges of the photocatalytic film are joined but also when the photocatalytic film is joined. The above-mentioned deterioration of the peel strength is more accurately caused by the passage of time after bonding, but the inventor of the present invention has described the reason why such a deterioration of strength may occur. I guess.
One of the common methods for producing a photocatalyst film is to apply a dispersion containing a photocatalyst powder and a fluorine resin to a fluorine resin film material, and then dry the dispersion and bake it at a high temperature. The photocatalytic layer is formed on the surface of the film material.
By the way, an additive such as a surfactant or the like is generally added to the above-mentioned dispersion liquid mainly for the purpose of enhancing the dispersibility of the fluorocarbon resin and the photocatalyst powder in the dispersion liquid. These additives remain in the photocatalyst layer for a certain period of time after calcination. Then, after the photocatalyst film is applied as a part of the film structure, the remaining additive is oxidized by ultraviolet light or photooxidation of the photocatalyst by irradiation of sunlight or the like, and is gradually decomposed. It becomes a decomposition product. Although the detailed mechanism is unclear at present, it is considered that the degradation of the peel strength of the joint is possibly caused by the decomposition product appearing on the surface of the photocatalytic film. In such a case, if it is a place other than the joint, no problem occurs because the decomposition product flows by rain etc. However, the decomposition product etc. is in the part where the photocatalyst layer and the fluorine resin film are in contact. The inventors of the present invention believe that, when is moved, the presence of decomposition products or the like moved to the bonding surface of the photocatalyst layer and the fluorine resin film causes the deterioration of the peel strength in the above-mentioned bonding portion.

  An object of the present invention is to reduce deterioration in peel strength of a bonded portion between photocatalyst films performed using a fluorine resin film.

  In order to solve the above-mentioned subject, this inventor proposes the following three inventions. For convenience, they are respectively referred to as a first invention, a second invention, and a third invention.

According to a first aspect of the present invention, the photocatalyst film has a photocatalyst layer containing a fluorocarbon resin and a photocatalyst powder on at least one surface thereof, and the photocatalyst film is superimposed on the photocatalyst film at a predetermined width. The fluorine resin film formed of the first fluorine resin which is a fluorine resin having a melting point equal to or lower than that of the basic fluorine resin which occupies a majority among the fluorine resins contained is sandwiched, and in this state, It is a bonding method of a photocatalytic film in which the overlapped portions of the photocatalytic film are bonded to each other through the fluororesin film by heating the overlapping portion.
In the first aspect of the invention, the fluorine resin film is a fluorine resin having a melting point equal to or less than that of the basic fluorine resin, which contains a carbonate having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less. The carbonate-containing layer is formed by using the one having a carbonate-containing layer formed of a second fluorine resin on at least one surface thereof and sandwiching the fluorine-containing resin film between overlapping portions of the photocatalyst film. It abuts on the photocatalyst layer.
As a result of researches by the inventor of the present invention, the decomposition product etc. produced by the ultraviolet rays or by the photooxidation of the photocatalyst from the additive remaining in the photocatalyst layer of the photocatalyst film has a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less To disappear by reaction with a certain carbonate, or to be adsorbed by carbonate, etc., to promote peeling at the interface between the photocatalyst film and the fluorine resin film after photooxidation occurs. I found that I lost some of the functionality I needed. In the first aspect of the invention, by superposing the overlapped portions of the photocatalytic film through the fluorocarbon resin film in a state in which the carbonate containing layer containing carbonate of the fluorocarbon resin film is in contact with the photocatalytic layer Later, after the photocatalytic film is applied as a part of the film structure, the decomposition product or the like generated from the additive by ultraviolet light or by the photooxidation action by the photocatalytic material is the photocatalytic layer and the carbonate containing layer of the fluororesin film. Even if it moves to the bonding surface, its decomposition product disappears by reaction with the carbonate, or it is adsorbed by the carbonate, etc., to promote peeling at the bonding interface between the photocatalyst film and the fluorine resin film. As described above, it loses some functions required for the above, so that the peel strength of the junction between the photocatalytic films is unlikely to drop over a long period of time.
As carbonates having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g, calcium carbonate (CaCO ₃ ), barium carbonate (BaCO ₃ ), magnesium carbonate (MgCO ₃ ), lithium carbonate (Li ₂ CO ₃₎ And strontium carbonate (SrCO ₃ ) can be used, and the above description of the carbonate applies to the second and third inventions.

As described above, the carbonate-containing layer in the first invention has a second fluororesin whose melting point is the same as or lower than that of the basic fluororesin, and has a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less It is formed by some carbonates. The second fluorine resin constituting the carbonate containing layer is made to be a fluorine resin having a melting point equal to or lower than that of the basic fluorine resin, by enhancing the meltability of the fluorine resin of the carbonate containing layer. It is because the peeling strength of a junction can be raised.
The method for producing a fluororesin film having a carbonate-containing layer formed on at least one surface of the first fluororesin is basically free. For example, the fluorine resin film has a melting point of 330 as a dispersion of FEP (tetrafluoroethylene / hexafluoropropylene copolymer) on at least one surface of a fluorine resin film substrate formed of the second fluorine resin. It can manufacture by apply | coating the dispersion liquid which added carbonate powder which is powder | flour of carbonate powder which is more than 2 degreeC and whose water solubility is 2 g / 100 g or less, and the dispersion liquid is dried. By further heating and calcining the FEP and the carbonate contained in the dispersion of FEP after drying the dispersion, the fixation of the first fluororesin and the carbonate-containing layer can be further strengthened. Since the fluorocarbon resin in the carbonate-containing layer on the surface of the fluorocarbon resin film melts at the time of bonding of the photocatalytic films, the above-mentioned firing process is not necessarily required.
In addition, a carbonate containing layer is provided in the surface of one side of the fluororesin film base material formed with the 2nd fluororesin, or both surfaces. The photocatalytic film to be bonded may have the photocatalytic layer only on one surface or on both surfaces. In the case where photocatalyst films having a photocatalyst layer on only one surface thereof are bonded to each other, the photocatalyst film is generally bonded with the direction of the surface having the photocatalyst layer aligned. In this case, only one surface of the fluorocarbon resin film sandwiched between the overlapping portions of the photocatalyst films is in contact with the photocatalyst layer. In this case, it is sufficient if the carbonate-containing layer is provided only on the surface of the fluorocarbon resin film that comes in contact with the photocatalyst layer. On the other hand, when the photocatalyst films having the photocatalyst layer on the both surfaces thereof are bonded to each other, both surfaces of the fluorocarbon resin film sandwiched between the overlapped portions of the photocatalyst films abut on the photocatalyst layer. In this case, the carbonate-containing layer is provided on both surfaces of the fluorine resin film to be in contact with the photocatalyst layer of the photocatalyst film.

The above-mentioned first fluororesin used for the fluororesin film of the first invention is also a fluororesin whose melting point is the same as or lower than that of the basic fluororesin, like the second fluororesin. The reason why the melting point of the first fluorocarbon resin is such, including the cases of the second and third inventions described below, the above-mentioned reasons why the melting point of the second fluorocarbon resin is such Is the same.
The “basic fluorine resin” in the photocatalyst film of the first invention is as follows. As described above, the photocatalyst film has a photocatalyst layer, and the photocatalyst layer contains a fluorocarbon resin. By the way, the photocatalyst film usually contains a fluorine resin also in the portion other than the photocatalyst layer. The fluorine resin contained in the photocatalyst layer and the fluorine resin contained in the portion other than the photocatalyst layer of the photocatalyst film may or may not be the same. In addition, the fluorine resin contained in the portion other than the photocatalyst layer of the photocatalyst film may be one type or two or more types. Thus, since a plurality of types of fluorocarbon resins in the photocatalyst film may be mixed or laminated, in the first invention, the fluorocarbon resin that accounts for the majority of the fluorocarbon resins contained in the photocatalyst film is defined as the basic fluorocarbon resin. (The standard for determining “majority” is weight.) For example, when the basic fluorocarbon resin is PTFE, a photocatalytic film in which a layer of FEP is provided on a relatively thick PTFE layer and a photocatalytic layer is provided thereon is an example of the basic fluorocarbon resin in the photocatalytic film. It becomes. The photocatalyst film may contain a material other than a fluorine resin, such as a base material woven with inorganic fibers such as glass fibers, glass beads for bulking the fluorine resin, etc. It does not affect the determination of which of the fluororesins that occupy the membrane is the basic fluororesin. The above description of the "basic fluorine resin" also applies to the second invention and the third invention.

  In the first invention, it is also possible to make the second fluororesin the same as the first fluororesin. As a result, when the photocatalyst films are bonded to each other, the fixation between the carbonate-containing layer of the fluorocarbon resin film and the first fluorocarbon resin can be further enhanced.

In the second invention as well, when photocatalyst films having a photocatalyst layer containing a fluorine resin and photocatalyst powder on at least one surface thereof are overlapped with a predetermined width, the photocatalyst film may be formed between the overlapped portions of the photocatalyst film. The fluorine resin film formed of the first fluorine resin which is a fluorine resin having a melting point equal to or lower than that of the basic fluorine resin which occupies a majority among the fluorine resins contained is sandwiched, and in this state, It is the bonding method of the photocatalyst film which joins the parts by which the said photocatalyst film was superimposed via the said fluororesin film by heating the part by which the superposition was carried out.
In the second aspect of the invention, a carbonate powder, which is a carbonate powder having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less, is attached to at least one surface of the fluorine resin film. When sandwiching the fluorine resin film between overlapping portions of the photocatalyst film, the surface of the fluorine resin film to which the carbonate powder is attached is brought into contact with the photocatalyst layer.
The second invention is different from the first invention in that the fluorocarbon resin film of the first invention has a carbonate-containing layer containing a second fluorocarbon resin and a carbonate on a film base formed of the first fluorocarbon resin. On the other hand, in the fluororesin film of the second invention, the carbonate powder is simply attached to at least one surface of the fluororesin film formed of the same first fluororesin as the film substrate. It is the point that
Even when using a fluorocarbon resin film to which such carbonate powder is attached, as in the case of the first aspect of the invention, the peel strength of the bonded portion in the case where the edges of the photocatalyst film are bonded is unlikely to drop over a long period.
The carbonate powder may be attached to at least one surface of the fluorocarbon resin film, but may be attached to both surfaces. The reason is the same as the case where the carbonate-containing layer is provided only on one side of the fluororesin film and the case where it is provided on both sides in the case of the first invention.

The method of adhering the carbonate powder to the fluororesin film may be any method.
For example, the adhesion of the carbonate powder to at least one surface of the fluorocarbon resin film can be performed by electrostatic adhesion by causing the fluorocarbon resin film to be electrostatically charged. Alternatively, the carbonate powder in which adhesion of the carbonate powder to at least one surface of the fluorocarbon resin film is spread on the at least one surface of the fluorocarbon resin film is applied to the at least one surface of the fluorocarbon resin film. It can do by pressing. These two methods can be used easily because the operation of attaching the carbonate powder to the fluororesin film can be performed at the site where the photocatalyst films are bonded to each other.
When bonding of the photocatalyst film is performed by sandwiching the fluororesin film between overlapping portions of the photocatalyst film, even if the fixation between the carbonate powder and the fluororesin film is not performed firmly, The effect of the second invention is not affected because carbonate powder can be disposed on the interface between the photocatalyst layer and the fluorine resin film.

In the third invention as well, when photocatalyst films having a photocatalyst layer containing a fluorine resin and photocatalyst powder on at least one surface thereof are overlapped with a predetermined width, the photocatalyst film may be formed between the overlapped portions of the photocatalyst film. The fluorine resin film formed of the first fluorine resin which is a fluorine resin having a melting point equal to or lower than that of the basic fluorine resin which occupies a majority among the fluorine resins contained is sandwiched, and in this state, It is the bonding method of the photocatalyst film which joins the parts by which the said photocatalyst film was superimposed via the said fluororesin film by heating the part by which the superposition was carried out.
In the third invention, as the fluororesin film, one to which a carbonate having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less is added is used.
The third invention is different from the first invention in that the fluorocarbon resin film of the first invention has a carbonate-containing layer containing a second fluorocarbon resin and a carbonate on a film base formed of the first fluorocarbon resin. On the other hand, the fluororesin film of the third aspect of the present invention is that the above-mentioned carbonate is added to the fluororesin film itself.
Even in the case of using a fluorocarbon resin film to which such carbonate powder is added, as in the case of the first aspect of the invention, the peel strength of the bonded portion in the case where the photocatalyst films are bonded hardly falls over a long period.
In the fluorine resin film according to the third aspect of the present invention, the carbonate is present in the whole in the first place, and therefore, even when the photocatalyst film has a photocatalyst layer only on one side, it has a photocatalyst layer on both sides. Can also respond.

Various basic fluorine resins, first fluorine resins and second fluorine resins in the first to third inventions can be used. However, the basic fluorocarbon resin, the first fluorocarbon resin, and the second fluorocarbon resin need to satisfy the relationship as already described for the melting points thereof.
As a fluorocarbon resin used for the basic fluorocarbon resin, the first fluorocarbon resin, and the second fluorocarbon resin, polytetrafluoroethylene (hereinafter referred to as PTFE, melting point is 327 ° C.), copolymer of tetrafluoroethylene / ethylene ( Hereinafter, it is referred to as ETFE. Melting point is 260 to 270 ° C.), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (hereinafter referred to as PFA, melting point is 310 ° C.), tetrafluoroethylene / hexafluoropropylene Base copolymer (hereinafter referred to as FEP, melting point is 260 ° C.), polychlorotrifluoroethylene (hereinafter referred to as PCTFE, melting point is 220 ° C.), polyvinylidene fluoride (hereinafter referred to as PVDF), the melting point 151-178 ° C.), polyvinyl fluoride (hereinafter referred to as PVF) Say. Melting point can be given a 203 ° C..) And the like.
For example, PTFE, ETFE, or FEP can be used as the basic fluorocarbon resin, and FEP can be used as the first fluorocarbon resin.

Sectional drawing which shows notionally the content of the joining method of the fluorine resin films implemented by one Embodiment of this invention. FIG. 2 is a cross-sectional view showing the configuration of the photocatalyst film shown in FIG. 1. The side view which shows the relationship of a photocatalyst film and a fluororesin film when joining is performed using the joining method of photocatalyst films demonstrated in FIG.

Hereinafter, preferred first, second and third embodiments of the present invention will be described.
A common symbol is attached to a common target in each embodiment, and a common description is sometimes omitted.

First Embodiment
In the first embodiment, as shown in the perspective view of FIG. 1, the two photocatalytic films 1 are superposed and joined to a portion to be superposed with a predetermined width via the sandwiched fluororesin film 2. Thus, the two photocatalytic films 1 are bonded.
In FIG. 1, the edges of the photocatalytic film 1 are bonded to each other with a predetermined width, and the edges of the photocatalytic film 1 are joined. It is not limited to each other.

The photocatalyst film 1 is, for example, an existing one, and is not limited to this, but is configured as shown in the cross-sectional view of FIG. The photocatalyst film 1 is provided with a base material which is a cloth formed by weaving or knitting the glass fiber 11 at the center thereof. The substrate in this embodiment is made of woven glass fibers 11. The base material is coated on both sides with a fluorocarbon resin layer 12 made of fluorocarbon resin. The fluorine resin forming the fluorine resin layer 12 can be appropriately selected from known fluorine resins, and can be, for example, any of PTFE, ETFE, PFA, FEP, PCTFE, PVDF, and PVF. In this embodiment, the fluororesin layer 12 is formed of PTFE (having a melting point of 327 ° C.). Although not shown, the fluorine resin layer 12 may be a multilayer such as a PTFE layer and an FEP layer.
A photocatalyst layer 13 is provided on the outermost layer of at least one of the fluorine resin layers 12. In the photocatalyst film 1 shown in FIG. 2, the photocatalyst layer 13 is provided only on one side of the photocatalyst film 1. The thickness of the photocatalyst layer 13 is relatively thin compared to the thickness of the fluororesin layer 12. The photocatalyst layer 13 contains a fluorocarbon resin and photocatalyst powder. In addition, an additive such as a surfactant used in the production process of the photocatalyst layer 13 at least during production of the photocatalyst film 1 itself or processing such as bonding (before occurrence of photocatalytic action by the photocatalyst), It remains slightly, though. The fluorine resin contained in the photocatalyst layer 13 may or may not be the same as the fluorine resin forming the fluorine resin layer 12, but in this embodiment, both are different. In this embodiment, the fluorine resin contained in the photocatalyst layer 13 is FEP.
As described above, the photocatalyst layer 13 is relatively considerably thinner than the fluororesin layer 12. Therefore, the fluorine resin that accounts for the majority of the weight ratio of the fluorine resin contained in the photocatalyst film 1 is PTFE that forms the fluorine resin layer 12. That is, the basic fluorine resin in the present application is PTFE in this embodiment.
The photocatalyst film 1 may not have the above-mentioned base material, and may be composed of the fluorine resin layer 12 and the photocatalyst layer 13.

Next, the fluorine resin film 2 will be described with reference to FIG.
The fluororesin film 2 is configured to include a film base 21 and a carbonate containing layer 22 covering at least one surface of the film base 21.
The film substrate 21 is basically made of only a fluorocarbon resin except residual substances such as a small amount of additives. The fluorine resin forming the film base 21 is a fluorine resin having a melting point equal to or lower than that of the basic fluorine resin, and corresponds to the first fluorine resin in the present application. Since the basic fluorine resin is PTFE as described above and the melting point thereof is 327 ° C., the fluorine resin forming the film base 21 is selected from those having a melting point of 327 ° C. or less. Although not limited to this, in this embodiment, the fluorine resin forming the film substrate 21 is FEP whose melting point is 260 ° C. The carbonate-containing layer 22 contains a fluorocarbon resin and a carbonate powder. The fluorine resin contained in the carbonate-containing layer 22 is a fluorine resin having a melting point equal to or lower than that of the basic fluorine resin, and corresponds to the second fluorine resin in the present application. Although not limited to this, in this embodiment, the fluorine resin contained in the carbonate containing layer 22 is FEP. When the fluorine resin contained in the carbonate-containing layer 22 is FEP, the fluorine resin contained in the carbonate-containing layer 22 and the fluorine resin constituting the film substrate 21 are the same, but these are necessarily the same. It does not have to be.
In addition, it is preferable to use the fluororesin below the melting | fusing point of a basic fluorine resin, and, more preferably, the fluorine resin which forms the film base 21 and the carbonate content layer 22 form the film base 21. It is preferable to use the fluorine resin below the melting | fusing point of a basic fluorine resin about both of the contained fluorine resin. This enables more robust bonding.

Such a fluororesin film 2 can be manufactured, for example, as follows.
In this embodiment, the fluorocarbon resin film 2 is a carbonate having a melting point of 330 ° C. or higher and a water solubility of 2 g / 100 g in the dispersion of FEP on at least one surface of the film substrate 21 formed of FEP. It was prepared by applying a dispersion to which calcium carbonate was added, and drying the dispersion. Note that as carbonates satisfying the above conditions, any of calcium carbonate (CaCO ₃ ), barium carbonate (BaCO ₃ ), magnesium carbonate (MgCO ₃ ), lithium carbonate (Li ₂ CO ₃ ), and strontium carbonate (SrCO ₃ ) Or it is possible to use a combination.
For example, the film substrate 21 may be formed into a film by melt extrusion of FEP pellets as a fluorocarbon resin as a raw material, or a thin dispersion of FEP is coated on the surface of a metal plate such as stainless steel and dried. Although it can also manufacture by baking and peeling from a metal plate, you may use the existing fluorine resin film. As the existing fluorine resin film, there are Neflon FEP film etc. which Daikin Industries, Ltd. manufactures and sells, for example.
A dispersion obtained by adding calcium carbonate powder to the dispersion of FEP for forming the carbonate-containing layer 22 is a FEP aqueous dispersion (solid content 54% by weight, manufactured by Mitsui-Dupont Fluorochemicals Co., Ltd., part number: FEP 120- JR 1000g, calcium carbonate powder with a particle size of 10 to 20μm (Kishida Chemical Co., Ltd., product number: 000-13435) 0.54g to 54g, purified water 1000g, silicone surfactant (momentive performance · · · In a container, 40 g of Materials Japan LLC., Product number: SILWET L-77) was mixed in a container and adjusted by stirring. Although the particle size of the carbonate is not limited to the above range, it is preferable to use one having a particle size of 0.03 to 100 μm, more preferably one having a particle size of 1 to 30 μm. That's good.
The above dispersion was applied to both sides of the film substrate 21 by a dip coating method, naturally dried, and then dried at 60 ° C. for 5 minutes to form a carbonate-containing layer 22. After this, baking may be performed at or above the temperature of the melting point of FEP, but this is omitted in this embodiment.
The weight ratio of calcium carbonate powder to FEP in the dried carbonate-containing layer 22 can be 0.1% to 10%, and more preferably 0.1% to 5%. By using the fluorine resin film 2 in which the carbonate content layer 22 in the weight ratio in the above range is laminated for joining of the photocatalytic film, sufficient peel strength of the joined portion is maintained even after a certain period of time after generation of photocatalytic action. Is possible.

The fluororesin film 2 as described above is formed by cutting or the like so as to correspond to the shape and size of the portion to which the photocatalyst film 1 is to be joined, and as shown in FIG. Sandwich between the parts to be overlapped with a predetermined width of. Then, in this state, the heat plate is pressed against the overlapped portion of the two photocatalytic films 1 while being heated and thermally welded. For such heat welding, a known hot plate welding machine can be used. The heating temperature at this time was at least the melting point of FEP, and in this embodiment, it was heated at 370 ° C. for 70 seconds. Thus, the superimposed portions of the photocatalyst film 1 are bonded to each other via the fluorine resin film.
When the fluororesin film 2 is sandwiched between overlapping portions of two photocatalyst films 1, the carbonate-containing layer 22 of the fluororesin film 2 is brought into contact with the photocatalyst film 13 of the photocatalyst film 1. Arrange as.
The photocatalyst film 1 has one having the photocatalyst layer 13 only on one side as shown in FIG. 3A, and one having the photocatalyst layer 13 on both sides as shown in FIG. 3B.
When the photocatalytic film 1 has the photocatalytic layer 13 on only one side, when bonding the photocatalytic film 1, the direction of the side on which the photocatalytic layer 13 of the two photocatalytic films 1 is present is usually aligned. In this case, only one surface of the fluorocarbon resin film 2 sandwiched between overlapping portions of the photocatalyst film 1 is in contact with the photocatalyst layer 13 of the photocatalyst film 1. Therefore, it is sufficient if the fluorocarbon resin film 2 used in this case is provided with the carbonate containing layer 22 on only one side thereof. The fluorine-containing resin film 2 may be sandwiched between overlapping portions of the two photocatalyst films 1 so that the carbonate-containing layer 22 on one surface side is in contact with the photocatalyst layer 13. However, even in this case, the fluorocarbon resin film 2 having the carbonate containing layer 22 on both sides can be used. Then, even if the fluorine resin film 2 is sandwiched between overlapping portions of the photocatalyst film 1 without considering the front and back of the fluorine resin film 2, the carbonate-containing layer 22 of the fluorine resin film 2 is the photocatalytic film 1. It will abut on the photocatalyst layer 13.
On the other hand, when the photocatalytic film 1 has the photocatalytic layer 13 on both sides, the fluorocarbon resin film 2 sandwiched between overlapping portions of the photocatalytic film 1 has the photocatalytic layer 13 of the photocatalytic film 1 on both sides. It will abut. Therefore, the fluorine resin film 2 used in this case needs to be provided with the carbonate containing layer 22 on both sides thereof.

Second Embodiment
Also in the second embodiment, the photocatalyst films 1 are bonded to each other.
The method is almost the same as in the first embodiment. What is different is the configuration of the fluorine resin film 2.
Unlike the case of the first embodiment, the fluorine resin film 2 of the second embodiment does not have the carbonate-containing layer 22 described in the case of the first embodiment on any surface thereof. That is, the fluororesin film 2 of the second embodiment may be the same as the film substrate 21 of the first embodiment.

Also in the method of bonding the photocatalyst films 1 according to the second embodiment, the fluororesin film 2 is formed by cutting or the like corresponding to the shape and size of the portion to which the photocatalyst film 1 is bonded, as shown in FIG. As described above, the two photocatalyst films 1 are sandwiched between the overlapping portions by a predetermined width, but in the second embodiment, the melting point is 330 ° C. or more and at least one surface of the fluorine resin film 2 before that. A carbonate powder having a water solubility of 2 g / 100 g or less is attached.
The method of making carbonate powder adhere to the fluororesin film 2 is, for example, to electrostatically charge the fluororesin film 2 and sprinkle carbonate powder on the fluororesin film 2 which has been electrostatically charged, or The carbonate powder is adhered to the fluororesin film 2 by, for example, inserting the electrostatic-charged fluororesin film 2 therein. As is well known, since the fluorocarbon resin has a property of being very easily electrostatically charged, it is possible to make the fluorocarbon resin film 2 electrostatically charged, for example, by rubbing the fluorocarbon resin film 2 with a suitable chemical fiber cloth You can do it easily.
The amount of carbonate powder to adhere to the fluorine resin film 2 may be a 0.01mg~0.8mg / cm ^2, preferably, it is preferable to 0.01mg~0.3mg / cm ^2. The particle size of the carbonate powder can be selected from the same range as in the first embodiment.
Alternatively, carbonate powder can be adhered to fluorine resin film 2 by coating carbonate powder on fluorine resin film 2 and pressing carbonate powder against fluorine resin film 2 with cloth or paper towel, for example. It is.
As described above, carbonate powder can be attached to the fluorine resin film 2, and the carbonate adhesion layer 22 can be used instead of the carbonate containing layer 22.
In addition, whether carbonate powder is made to adhere only to one side of the fluororesin film 2 or carbonate powder is made to adhere to both sides is the carbonate only on one side of the fluororesin film 2 of the first embodiment. It applies according to whether the containing layer 22 is provided or the carbonate containing layer 22 is provided on both surfaces.

As described above, the fluorocarbon resin film 2 to which calcium carbonate powder is attached is sandwiched between the overlapping portions of the two photocatalyst films 1 with a predetermined width, and in this state, the two photocatalyst films 1 are overlapped. The joined portion is heated and thermally welded under the same conditions as the first embodiment while being pressed by a hot plate welding machine.
Thus, the superimposed portions of the photocatalyst film 1 are bonded to each other via the fluorine resin film.

Third Embodiment
Also in the third embodiment, the photocatalyst films 1 are bonded to each other.
The method is almost the same as in the first embodiment. What is different is the configuration of the fluorine resin film 2.
The fluorine resin film 2 of the third embodiment is obtained by adding carbonate powder having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less to FEP which is the first fluorine resin described in the first embodiment. It has become.
The manufacturing method of such a fluororesin film 2 is as follows.

The fluorocarbon resin film 2 has a melting point of 330 ° C. or higher and a water solubility of 2 g / 100 g or less, for example, in 10 kg of pellets of FEP as a fluorocarbon resin (Mitsui Dupont Fluoro Chemical Co., Ltd., product number: FEP 100-J) Add 1 g to 500 g of calcium carbonate powder (manufactured by Shiroishi Calcium Co., Ltd., product number: Softon 1200) having an average particle diameter of 1.8 μm as a carbonate powder, and melt at 320 ° C. using a known melt extruder It can be processed into a film by extrusion molding.
Moreover, it is also possible to knead | mix the said pellet and calcium carbonate powder at 320 degreeC with a well-known twin-screw kneading extruder, and to process it into a film form with a well-known compression molding machine after that.
In these cases, the weight ratio of carbonate powder to fluorocarbon resin can be in the range of 0.01% to 5%, preferably 0.1% to 3%.

The fluorocarbon resin film 2 containing carbonate powder obtained as described above is sandwiched between the overlapping portions of the two photocatalyst films 1 with a predetermined width, and in that state, the two photocatalyst films are The overlapped portion of 1 is heated and heat-welded while being pressed by a hot plate welding machine.
Thus, the superimposed portions of the photocatalyst film 1 are bonded to each other via the fluorine resin film.
In the fluorocarbon resin film 2 of the third embodiment, since carbonate powder is dispersed throughout the entire surface including both surfaces, even when the photocatalyst film 1 to be joined has the photocatalyst layer 13 only on one side, It is possible to apply to the case of having both sides.

  Hereinafter, experimental examples will be described. First, the method for producing the sample used in the experimental example is also described.

<Sample 1>
[Sample 1-1]
The following was produced as an example of the fluororesin film 2 of the first embodiment.
A dispersion obtained by adding carbonate powder to the dispersion of FEP for forming the carbonate-containing layer 22 of the fluorocarbon resin film 2 of Sample 1-1 was a FEP aqueous dispersion (solid content: 54% by weight, Mitsui · · 1000 g of Dupont Fluoro Chemical Co., product number: FEP 120-JR, 4 g of calcium carbonate powder (Kishida Chemical Co., product number: 000-13435) with a particle diameter of 10 to 20 g, 1000 g of purified water In a container, 40 g of surfactant (manufactured by Momentive Performance Materials Japan Co., Ltd., part number: SILWET L-77) was mixed in a container and adjusted by stirring.
The above dispersion is applied to both sides of an FEP film substrate (FEP film with a thickness of 0.125 mm) 21 by dip coating, naturally dried, and then dried at 60 ° C. for 5 minutes to form a carbonate-containing layer 22 The formed fluororesin film 2 was produced.
The weight ratio of calcium carbonate powder to FEP in the dried carbonate-containing layer 22 is 0.7%.

[Sample 1-2]
The following were produced as another example of the fluororesin film 2 of the first embodiment.
A dispersion obtained by adding carbonate powder to the dispersion of FEP for forming the carbonate-containing layer 22 of the fluororesin film 2 of Sample 1-2 was a FEP aqueous dispersion (54 wt% solid content, Mitsui · · 1000 g of Dupont Fluoro Chemical Co., product number: FEP 120-JR, 7 g of calcium carbonate powder with a particle diameter of 10 to 20 μm (Kishida Chemical Co., product number: 000-13435), 1000 g of purified water, silicone type In a container, 40 g of surfactant (manufactured by Momentive Performance Materials Japan Co., Ltd., part number: SILWET L-77) was mixed in a container and adjusted by stirring.
The above dispersion is applied to both sides of a FEP film substrate (FEP film with a thickness of 0.125 mm) 21 by dip coating, naturally dried, and then dried at 60 ° C. for 5 minutes to form a carbonate-containing layer 22 The resulting fluororesin film 2 was produced.
The weight ratio of calcium carbonate powder to FEP in the dried carbonate-containing layer 22 is 1.2%.

[Sample 1-3]
As still another example of the fluororesin film 2 of the first embodiment, the following was produced.
A dispersion obtained by adding calcium carbonate powder to the dispersion of FEP for forming the carbonate-containing layer 22 of the fluororesin film 2 of Sample 1-3 was a FEP aqueous dispersion (solid content: 54% by weight, Mitsui · · Dupont Fluoro Chemical Co., Ltd., product number: FEP 120-JR 1000g, particle diameter of 10 to 20 μm calcium carbonate powder (Kishida Chemical Co., Ltd., product number: 000-13435) 18g, purified water 1000g, silicone system In a container, 40 g of surfactant (manufactured by Momentive Performance Materials Japan Co., Ltd., part number: SILWET L-77) was mixed in a container and adjusted by stirring.
The above dispersion is applied to both sides of a FEP film substrate (FEP film with a thickness of 0.125 mm) 21 by dip coating, naturally dried, and then dried at 60 ° C. for 5 minutes to form a carbonate-containing layer 22 The resulting fluororesin film 2 was produced.
The weight ratio of calcium carbonate powder to FEP in the dried carbonate-containing layer 22 is 3.2%.

<Sample 2>
[Sample 2-1]
The following was produced as an example of the fluororesin film 2 of the second embodiment.
Sample 2-1 is a paper towel on a paper towel on a FEP film substrate 21 with a thickness of 0.125 mm, a length of 600 mm, and a width of 75 mm as calcium carbonate powder (manufactured by Shiroishi calcium, part number: softon 1200, average particle diameter 1. 8 .mu.m), and the calcium carbonate powder is adhered to both sides of the FEP film by rubbing on the FEP film, to form a fluorocarbon resin film 2 in which a carbonate adhesion layer 22 is formed instead of the carbonate-containing layer.
The adhesion amount of calcium carbonate in this calcium carbonate-adhered FEP film was 0.012 mg / cm ² .

[Sample 2-2]
The following were produced as another example of the fluororesin film 2 of the second embodiment.
Sample 2-2 is a paper towel on a paper towel on a FEP film substrate 21 with a thickness of 0.125 mm, a length of 600 mm, and a width of 75 mm as calcium carbonate powder (manufactured by Shiroishi calcium, part number: softon 1200, average particle size 1. A fluorocarbon resin film 2 was produced in which calcium carbonate powder was adhered to both sides of the FEP film by adhering 8 μm) and rubbing it to the FEP film to form a carbonate adhesion layer 22 instead of the carbonate containing layer.
The amount of calcium carbonate deposited on this calcium carbonate-deposited FEP film was 0.22 mg / cm ² .

<Sample 3>
[Sample 3-1]
The following was produced as an example of the fluororesin film 2 of the third embodiment.
Sample 3-1 is calcium carbonate powder (Shiroishi Calcium Co., Ltd., manufactured by Shiraishi Calcium Co., Ltd.) having an average particle size of 1.8 μm as carbonate in 10 kg of pellets of FEP (Mitsui Dupont Fluoro Chemical Co., Ltd., product number: FEP 100-J) Item No .: 0.125 mm thick calcium carbonate-containing FEP film manufactured by extruding while melting in the range of 320 to 380 ° C. using a known melt extruder by adding 10 g of softon 1200) is there.
In this case, the weight ratio of calcium carbonate powder to fluorine resin was 0.1%.

[Sample 3-2]
The following were produced as another example of the fluororesin film 2 of the third embodiment.
Sample 3-2 is 10 kg of pellets of FEP (Mitsui Dupont Fluorochemicals Co., Ltd., part number: FEP 100-J), calcium carbonate powder having an average particle diameter of 1.8 μm as carbonate (Shiroishi Calcium Co., Ltd., Product number: 100 g of softon 1200) added and manufactured by extruding while melting in the range of 320 to 380 ° C. using a known melt extruder, calcium carbonate containing 0.125 mm in thickness It is a FEP film.
In this case, the weight ratio of calcium carbonate powder to fluorine resin was 1.0%.

[Sample 3-3]
As still another example of the fluororesin film 2 of the third embodiment, the following was produced.
Sample 3-3 is calcium carbonate powder (Shiroishi Calcium Co., Ltd., manufactured by Shiraishi Calcium Co., Ltd.) having an average particle size of 1.8 μm as carbonate in 10 kg of pellets of FEP (Mitsui Dupont Fluorochemicals Co., product number: FEP 100-J) Product number: manufactured by extruding while melting in the range of 320 to 380 ° C. using 300 g of softon 1200) and using a well-known melt extruder, calcium carbonate containing 0.125 mm thick It is a FEP film.
In this case, the weight ratio of calcium carbonate powder to fluorine resin was 3.0%.

[Sample 3-4]
Although it tried to produce the following as another example of the fluororesin film 2 of 3rd Embodiment, the fluororesin film 2 was not able to be obtained.
In Sample 3-4, calcium carbonate powder (Shiroishi Calcium Co., Ltd., manufactured by Shiraishi Calcium Co., Ltd.) having an average particle size of 1.8 μm as carbonate in 10 kg of pellets of FEP (Mitsui, manufactured by DuPont Fluorochemicals, product number: FEP 100-J) Product number: 500 g of softon 1200) was added and extrusion was attempted while melting in the range of 320 to 380 ° C. using a known melt extruder, but foaming and holes were so severe that uniform films were formed It was difficult.
In this case, the weight ratio of calcium carbonate powder to fluorine resin was 5.0%.

<Sample for comparison>
As an alternative to the fluorine resin film 2, calcium carbonate is not contained or attached to a commercially available 0.125 mm thick FEP film used for Samples 1-1 to 1-3 and Samples 2-1 and 2-2. The case where it used as it was was prepared as a sample for comparative examples.

<Photocatalytic film>
The photocatalytic film contains about 0.2 mm of PTFE on both sides of a glass fiber fabric with an average thickness of 0.4 mm, and further contains a photocatalyst on the outermost layer of an existing membrane material coated with about 10 μm of FEP on both sides of the PTFE. The resulting FEP dispersion is applied to provide a photocatalyst layer.
The composition of the FEP dispersion containing the photocatalyst was as follows.
The dispersant is 2000 g of an aqueous dispersion (solid content of 28% by weight, custom-made product) using anatase-type TiO ₂ having a particle size of 1 nm to 100 nm, 3000 g of purified water, and an aqueous dispersion of FEP (54 wt% of solid content) , Mitsui Dupont Fluorochemicals Co., Ltd., part number: 4148 g silicone surfactant (Momentive Performance Materials Japan GK Co., part number: SILWET L-77) 137.2 g prepared respectively And they were mixed and prepared by stirring. The weight ratio of FEP to titanium oxide powder is 20:80.
The photocatalyst-containing FEP layer was coated in the following manufacturing process.
First, for the above-mentioned film material whose outermost layer is FEP, the above-mentioned dispersant is applied to both further layers by dipping coating method, dried at 60 ° C. for 3 minutes, and then the drying temperature is gradually raised Finally, the film material was calcined at 300 ° C. for 3 minutes and allowed to cool naturally, and a film material having FEP layers containing titanium oxide formed on both sides was experimentally manufactured as a photocatalyst film.

<Test content>
The photocatalyst film was joined by heat welding with the fluorine resin film 2 according to the above samples and comparative examples interposed therebetween, and the peel strength was tested.

[Heat welding]
Bonding of the photocatalytic film sandwiching the fluorine resin film 2 by heat welding was performed in the following manner.
Two sheets of the photocatalytic film cut into a width of 150 mm and a length of 600 mm are stacked, and between them, the calcium carbonate-containing FEP dispersion prepared in Samples 1-1 to 1-3, which acts as an adhesive, is applied FEP films (width 75 mm, length 600 mm), FEP films (width 75 mm, length 600 mm) to which calcium carbonate prepared in samples 2-1 and 2-2 adhered, samples 3-1 to 3-3 were prepared One piece of calcium carbonate-containing FEP film (width 75 mm, length 600 mm) or FEP film (width 75 mm, length 600 mm) to which calcium carbonate of the comparative example is not attached is sandwiched, heat plate set temperature 370 ° C., welding time Each bonding sample having a width of 75 mm and a length of 600 mm was produced under the conditions of 70 seconds and a pressure of 0.5 kg / cm ² .

[Collection of exfoliation test sample]
As a peel test sample from each of the above-mentioned bonded samples, two sheets of 50 mm wide and 150 mm long are cut out from the central portion in the longitudinal direction of 75 mm wide and 600 mm long as a peel test sample. The remaining sheet was used as a sample, and was used as a sample for evaluation of a peel test after exposure which will be described later 1000 hours after the accelerated exposure test.

Accelerated exposure test
The accelerated exposure test uses a xenon weather meter (Suga Test Instruments SX 75-2, irradiance 180 W / m ² (300 to 400 nm), 18 minutes in 120 minutes: irradiation + water spray, 102 minutes in 120 minutes: irradiation only) An exposure of 1000 hours was performed on the sample for evaluation of the peel test after the exposure.

[Peeling test]
Peeling tests were performed on the above-described initial peel test evaluation sample and the post-exposure peel test evaluation sample.
The peeling test was performed according to (JIS K6404-5, method B). However, the size of the test piece to be subjected to one peeling test is 20 mm in width × 150 mm in length, 2 from each of the sample for evaluation of initial peeling test of 50 mm in width × 150 mm in length and the sample for evaluation of peeling test after exposure. Each book was collected.
Of these test pieces, a portion of 50 mm from one end side in the longitudinal direction was peeled off by hand, and then a peeling test was performed using a tensile tester. The evaluation of the peel test results was carried out by visually judging the proportion of the part peeled between the fluorocarbon resin and the glass fiber fabric on the surface peeled off after the peel test, and the average value of the two was evaluated.
In general, with such materials, the peel strength is generally high when the fluorocarbon resin and the glass base are peeled off, but the peel strength when the fluorocarbon resin and the fluorocarbon resin are peeled is relatively low. It is because it is known.

※「初期剥離試験評価用サンプル」と、「暴露後剥離試験評価用サンプル」の各数値は、剥離した面のうちガラス繊維織物とフッ素樹脂の間で剥離した部分の割合（％）
※「剥離強度の向上度の評価」の上欄の各数値は、比較用試料と比較した場合に向上した分の数値
※「剥離強度の向上度の評価」の下欄の○、△、×は、比較用試料と比較した場合に向上した分の数値に基づき、剥離強度の向上の程度を、以下の評価凡例により３段階で評価した評価結果
×：１０％未満
△：１０〜２５％
○：２５％以上 [Peeling test result]
Peeling tests were performed on the sample for evaluation of initial peeling test and the sample for evaluating peeling test after exposure. Table 1 below shows the ratio of the area in which peeling occurred between the glass fiber fabric and the fluorocarbon resin (PTFE) in the photocatalyst film in the total area of the bonding portion and the evaluation result of the improvement in the peeling strength. .

※ Each numerical value of "sample for initial peel test evaluation" and "sample for evaluation for peel test after exposure" is the percentage of the part peeled off between the glass fiber fabric and the fluorine resin in the peeled surface (%)
※ Each numerical value of the upper column of "evaluation of improvement in peel strength" is the numerical value of the minute when compared with the sample for comparison ※ ○ in the lower column of "evaluation of improvement in peel strength", 、, × The evaluation result of evaluating the degree of improvement of the peel strength in three stages by the following evaluation legend based on the numerical value of the minute when compared with the sample for comparison: x: less than 10% Δ: 10 to 25%
○: 25% or more

As described above, regardless of whether bonding was performed by sandwiching Sample 1-1 to Sample 3-3 between photocatalyst films or bonding was performed by sandwiching a comparative sample between photocatalyst films, for evaluation of initial peeling test In the case of the peeling test of a sample, each numerical value of "sample for initial peeling test evaluation" is 100%. This is because the peeling is compared with the photocatalytic film and the comparative sample, even when the same comparative sample as in the prior art is used for bonding or when the sample 1-1 to sample 3-3 are used for bonding. In other words, it means that everything is generated inside the photocatalytic film, not between the photocatalytic film and the sample 1-1 to the sample 3-3, that is, not the bonding surface between the joined photocatalytic films. That is, in the state where it did not pass through the accelerated exposure test, even when bonding was performed by sandwiching Sample 1-1 to Sample 3-3 between the photocatalyst films, bonding was performed by sandwiching the comparative sample between the photocatalyst films. Also in the case, it is understood that the strength of the bond between the photocatalyst films is higher as the destruction of the photocatalyst film occurs before the peeling at the bonding surface of the bonded photocatalyst films.
On the other hand, when bonding is performed by sandwiching the comparative sample between the photocatalytic films, the numerical value of the “post-exposure peel test evaluation sample” is 55%. This means that when 45% of the bonding portion was subjected to the peeling test, peeling occurred at the bonding surface of the bonded photocatalyst layers prior to the destruction of the photocatalyst film. That is, it is understood that the strength of the bonding portion formed by sandwiching the comparative sample between the photocatalytic films may be deteriorated when the accelerated exposure test is performed.
On the other hand, when bonding is performed by sandwiching sample 1-1 to sample 3-3 between the photocatalyst films, the numerical values of “sample for evaluation of exfoliation test after exposure” are 65% to 100%. In the case where the bonded portion in which the sample 1-1 to sample 3-3 is bonded by sandwiching the photocatalytic film is joined by sandwiching the comparative sample between the photocatalytic films even after the exposure test, In comparison, the deterioration of the peel strength is smaller. In particular, with regard to the sample 2-2 having the above numerical value of 100%, since it has the same joint strength as the joint not subjected to the exposure test, it can be said that the deterioration of the peel strength is not substantially. As for the other samples, the lowest value is 65%, so compared to the case where the comparative sample having the value of 55% is sandwiched between the photocatalyst films, the peeling strength of the bonding portion is An improvement has been seen. Sample 1-2, Sample 1-3, Sample 2-1, and Sample with evaluation of "o" in the lower column of "Evaluation of the degree of improvement in peel strength" except for the case where Sample 2-2 is used 3-2 shows that the drop in peel strength of the joint from before the exposure test is small even after the exposure test.
Even when other carbonates, ie, barium carbonate, magnesium carbonate, lithium carbonate and strontium carbonate, were used, substantially the same results as the test results were obtained.

DESCRIPTION OF SYMBOLS 1 photocatalyst film 2 fluorine resin film 11 glass fiber 12 fluorine resin layer 13 photocatalyst layer 21 fluorine resin film base 22 carbonate containing layer

Claims (12)

Photocatalytic films having a photocatalytic layer containing a fluorocarbon resin and a photocatalytic powder on at least one surface thereof are overlapped with each other at a predetermined width,
During the superposition of the photocatalytic film, it is formed of the first fluorocarbon resin which is the same as or lower than the basic fluorocarbon resin which is a fluorocarbon resin that occupies the majority among the fluorocarbon resins contained in the photocatalytic film. Sandwich the fluorinated resin film,
It is a joining method of the photocatalyst film which joins the parts by which the photocatalyst film was piled up via the fluoro resin film by heating the piled part of the photocatalyst film in the state,
The fluorine resin film is formed of a second fluorine resin having a melting point equal to or less than that of the basic fluorine resin, which contains a carbonate having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less Using one having a carbonate-containing layer on at least one side,
The carbonate-containing layer is brought into contact with the photocatalyst layer when the fluororesin film is sandwiched between the overlapped portions of the photocatalyst film.
Bonding method of photocatalytic film. The fluorine resin film applies a dispersion obtained by adding carbonate powder, which is powder of carbonate, to a dispersion of FEP on at least one surface of a fluorine resin film substrate formed of a second fluorine resin, Manufactured by drying the dispersion,
A method of bonding a photocatalytic film according to claim 1. The second fluororesin may be the same as the first fluororesin,
The joining method of the photocatalyst film of Claim 1 or 2. Photocatalytic films having a photocatalytic layer containing a fluorocarbon resin and a photocatalytic powder on at least one surface thereof are overlapped with each other at a predetermined width,
Between the overlapped portions of the photocatalytic film, a first fluorocarbon resin having a melting point equal to or lower than that of a basic fluorocarbon resin which is a fluorocarbon resin that occupies a majority among the fluorocarbon resins contained in the photocatalytic film Sandwich the fluorine resin film formed by
It is a joining method of the photocatalyst film which joins the parts by which the photocatalyst film was piled up via the fluoro resin film by heating the piled part of the photocatalyst film in the state,
As the fluorine resin film, a film in which a carbonate powder, which is a powder of carbonate having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less, is used on at least one surface thereof
When sandwiching the fluorine resin film between overlapping portions of the photocatalyst film, the surface of the fluorine resin film to which the carbonate powder is attached is brought into contact with the photocatalyst layer.
Bonding method of photocatalytic film. The adhesion of the carbonate powder to at least one surface of the fluorocarbon resin film is performed by electrostatic adhesion by causing the fluorocarbon resin film to be electrostatically charged.
The joining method of the photocatalyst film of Claim 4. The adhesion of the carbonate powder to at least one surface of the fluorocarbon resin film is pressed against the at least one surface of the fluorocarbon resin film, the carbonate powder being spread on the at least one surface of the fluorocarbon resin film By
The joining method of the photocatalyst film of Claim 4. Photocatalytic films having a photocatalytic layer containing a fluorocarbon resin and a photocatalytic powder on at least one surface thereof are overlapped with each other at a predetermined width,
Between the overlapped portions of the photocatalytic film, a first fluorocarbon resin having a melting point equal to or lower than that of a basic fluorocarbon resin which is a fluorocarbon resin that occupies a majority among the fluorocarbon resins contained in the photocatalytic film Sandwich the fluorine resin film formed by
It is a joining method of the photocatalyst film which joins the parts by which the photocatalyst film was piled up via the fluoro resin film by heating the piled part of the photocatalyst film in the state,
As the fluororesin film, one to which a carbonate having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less is added is used.
Bonding method of photocatalytic film. The basic fluorine resin is PTFE,
A method of bonding a photocatalytic film according to any one of claims 1, 4 or 7. The first fluororesin is FEP,
A method for bonding a photocatalytic film according to any one of claims 1, 4, 7 or 8. A first fluorine resin having a melting point equal to or lower than that of a basic fluorine resin which is a fluorine resin which occupies a majority of the fluorine resins contained in the photocatalyst film, which is used in the method of bonding a photocatalyst film according to claim 1 A fluorine resin film formed of a resin,
A carbonate-containing fluororesin layer comprising a carbonate having a melting point of 330 ° C. or more and a water solubility of 2 g / 100 g or less, which is the same as or lower than the basic fluororesin A fluororesin film having at least one surface thereof. A first fluorine resin having a melting point equal to or lower than that of a basic fluorine resin which is a fluorine resin which occupies a majority of the fluorine resins contained in the photocatalyst film, which is used in the method of bonding a photocatalyst film according to claim 7 A fluorine resin film formed of a resin,
The fluororesin film to which the said carbonate was added. The carbonate is calcium carbonate,
The joining method of the photocatalyst film in any one of Claim 1, 4, or 7-9.

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