JPH1044346A - Stainproof film and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stainproof film having high mechanical strength and excellent adhesive force by forming a fluororesin layer containing no titanium oxide on one side surface of a fluororesin layer containing titanium oxide particles. SOLUTION: The stainproof film 1 comprises a fluororesin layer 12 containing no titanium oxide formed on one side surface of a fluororesin layer 11 containing titanium oxide particles. The film 1 is laminated on a surface of an object 3 to be protected by using an adhesive layer 2. The layer 12 containing on titanium oxide particles is interposed between the layer 11 containing the particles and the layer 2 thereby to prevent oxidation deterioration of the layer 2 due to the particles. Since high mechanical strength of the entire film 1 is secured by the layer 12 containing no titanium oxide, the degree of exposure of the particles can be increased by mixing a large quantity of particles or reducing in thickness the layer 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling film which is attached to the surface of an object to be protected to prevent contamination, and to a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a method of protecting a steel plate or a wall material and preventing the adhesion of dirt, there is a method of coating the surface of the plate with a fluororesin. As the coating method, a method of applying a fluororesin paint on the surface of the object to be protected, or a tetrafluoroethylene-perfluoroalkylvinyl copolymer (PFA), an ethylene-tetrafluoroethylene copolymer (ETFE), or polyvinyl Fluoride (PV
There is a method of attaching a resin film made of a molten fluororesin such as F) by lamination. Since the fluororesin has good wiping properties, when coated with such a fluororesin, for example, when coating a kitchen product, even if the surface is soiled, the dirt can be easily removed by wiping. However, in the case of persistent stains such as oil stains and dirt, even if it is wiped off, a small amount of dirt remains, and if you try to forcibly wipe it off, the paint on the coated type may peel off. In the case of a molten fluororesin film, the surface of the film may be damaged, which may promote contamination in the future.

[0003] Further, when such a fluororesin coating material is used for an object to be protected which is installed outdoors or the like,
There is a problem that fine particles such as smoke, dust, fine sand and the like in the air adhere to the surface of the fluororesin coating material and stain the appearance. This is because, in the case of a wall material or the like installed outdoors, it is difficult to perform wiping, and even if it is washed with water, it is difficult to wash away the attached fine particles because the fluororesin is water repellent. .

On the other hand, it is known that titanium oxide, which is a photocatalyst, exhibits a so-called photocatalytic reaction in which electrons excited by absorbing light decompose by oxidizing an approaching organic substance or microorganism. Therefore, various antifouling and antibacterial techniques have been developed by utilizing the photocatalytic action of titanium oxide, and various studies have been made particularly on a method of supporting titanium oxide.

For example, in Japanese Patent Application Laid-Open No. Hei 6-315614, a powder of a photocatalyst containing titanium dioxide or a mixture of titanium dioxide and activated carbon as a main component is molded into a sheet or panel using a synthetic resin or the like and fixed outdoors. An air purifying material has been proposed. Further, Japanese Patent Application Laid-Open No. 7-26571
In Japanese Patent Application Publication No. 4 (1999) -1994, for the purpose of preventing the adhesion of dirt, a photocatalyst particle in which a fluororesin or the like is supported as a binder on a part of its surface is proposed.

In addition, there is a method in which a photocatalyst such as titanium oxide is contained in a resin film. According to this, the object can be provided with stain resistance and the like simply by sticking the film. However, due to the strong oxidizing power of titanium oxide,
There is a problem that the resin film itself, which is a carrier, is oxidized. Therefore, as the material of the resin film, a polymer material having an antioxidant power, for example, a material such as polytetrafluoroethylene (PTFE) is selected. There is a need.
At this time, the photocatalytic action of titanium oxide is realized by the direct contact between the titanium oxide and the substance to be oxidized. It is desirable that the degree of exposure be large.

[0007]

As described above, when a fluororesin film containing a photocatalyst such as titanium oxide is used for protecting an object and preventing dirt from adhering, the adhered particles are smaller than those of a conventional fluororesin coating material. Since it is decomposed as needed at the time of light irradiation, surface contamination hardly occurs, and residues at the time of wiping can be decomposed and removed. However, when a film in which titanium oxide having a photocatalytic function is contained in PTFE is used by attaching it to a coating via an adhesive layer such as an adhesive or an adhesive for the purpose of antifouling and antibacterial, use a film. Due to the oxidizing power of the titanium oxide due to the transmitted light, the bond between the adhesive component or the film and the adhesive layer is deteriorated, the adhesive strength is lost, and there is a case where floating occurs and finally peels off. Further, in order to strengthen the antifouling and antibacterial effects, it is necessary to increase the degree of exposure of titanium oxide. However, if the content of titanium oxide is increased, the mechanical strength of the film may be reduced.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to provide an antifouling film having high mechanical strength and excellent adhesive strength, and a method for producing the same.

[0009]

In order to achieve the above object, an antifouling film of the present invention comprises a fluororesin layer containing titanium oxide particles, a fluororesin layer containing no titanium oxide particles, and an inorganic fiber. The configuration is such that at least one of the fabric layers is formed.

That is, the antifouling film of the present invention is characterized in that a layer exhibiting stain resistance is separated from a layer which secures adhesiveness and mechanical strength. The fluororesin layer containing the titanium oxide particles has an effect of oxidatively decomposing organic substances and microorganisms by the photocatalytic action of the titanium oxide particles. The fluororesin layer or the inorganic fiber cloth layer not containing the titanium oxide protects an adhesive layer and the like formed when the antifouling film is adhered to the object to be protected from the oxidizing action of the titanium oxide particles. . And, since the fluororesin layer or the inorganic fiber cloth layer also acts as a reinforcing layer, a large amount of titanium oxide particles are blended in the fluororesin layer to increase the degree of exposure, or the fluororesin layer is thinned. However, the strength of the film as a whole is sufficient, and the stain resistance is extremely excellent.

The fluorine resin used in the present invention can withstand the oxidizing power of the titanium oxide particles due to the light transmitted through the film,
There is no particular limitation as long as the raw material resin is provided as a dispersion. For example, PTFE, PF
A, tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and the like. Of these, PTFE is preferred because of its excellent chemical stability and the like.

The inorganic fiber cloth forming the inorganic fiber cloth layer is not particularly limited as long as it is durable to the oxidizing power of titanium oxide.
A glass fiber cloth is mentioned, and a glass fiber cloth is preferred from the viewpoints of dimensional stability, cost and handleability.

In the present invention, the fluororesin layer containing the titanium oxide particles is preferably non-porous.
By doing so, the stain resistance of the film surface is further improved, and the film strength is further improved. In addition, by making it non-porous, the contact area of airborne substances such as soot, dust, fine sand and the like, or oil stains can be reduced.

Preferably, the titanium oxide particles are exposed from the surface of the fluororesin layer. In this case, a photocatalytic reaction easily occurs on the titanium oxide on the surface of the film, and the decomposition and removal of dirt can be performed efficiently.

In the present invention, the weight ratio between the titanium oxide particles and the fluororesin in the fluororesin layer containing the titanium oxide particles is usually determined by considering the degree of exposure of the titanium oxide particles and the like. = 1: 9-7:
3, and preferably in the range of titanium oxide particles: fluororesin = 3: 7 to 6: 4.

In the present invention, the surface of the fluororesin containing no titanium oxide particles is preferably subjected to a surface roughening treatment to improve the adhesiveness.

[0017] In addition, because the workability in attaching to the object to be protected is improved, the surface of the antifouling film of the present invention on the side opposite to the side on which the fluororesin layer containing the titanium oxide particles is located. It is preferable that an adhesive layer or a pressure-sensitive adhesive layer is formed on the substrate.

Next, the method for producing an antifouling film according to the present invention comprises the steps of applying a dispersion containing a fluororesin and titanium oxide particles on at least one of a fluororesin sheet and an inorganic fiber cloth; And a step of baking the fluororesin to form a fluororesin containing titanium oxide particles.

According to this method, the titanium oxide particles can be exposed from the surface of the fluororesin layer, and the surface other than the exposed portion can be formed densely. Also, according to this method,
The thickness of the titanium oxide particle-containing fluororesin layer or the like can be freely adjusted by changing the concentration and application amount of the dispersion.

In the method for producing an antifouling film of the present invention, the weight ratio of the titanium oxide particles to the fluororesin is preferably in the range of titanium oxide particles: fluororesin = 1: 9 to 6: 4.

[0021]

Next, the present invention will be described in detail.

FIG. 1A is a sectional view showing an example of the configuration of the antifouling film 1 of the present invention. In the figure, reference numeral 11 denotes a fluororesin layer containing titanium oxide particles, and a fluororesin layer 12 containing no titanium oxide is formed on one side (the lower side in the figure). The fluororesin layer 11
Has a thickness of usually 5 to 50 μm, preferably 10 to 50 μm.
３０30 μm. The thickness of the fluororesin layer 12 is usually 5 to 50 μm, preferably 5 to 15 μm. FIG. 1B shows a state in which the antifouling film is adhered to the surface of the object to be protected using an adhesive or a pressure-sensitive adhesive. In the figure, reference numeral 2 denotes an adhesive layer or a pressure-sensitive adhesive layer, reference numeral 3 denotes an object to be protected, and other parts that are the same as those in FIG. As described above, when affixed to an object to be protected using an adhesive or the like, the fluorine resin layer 12 containing no titanium oxide particles is interposed between the fluorine resin layer 11 containing titanium oxide particles and the adhesive layer 2. Adhesive layer 2
Is not oxidized and deteriorated by titanium oxide, and a sufficient adhesive strength can be maintained for a long time. The fluororesin layer 1
2, the mechanical strength of the antifouling film 1 is also sufficient. In this example, the same effect can be obtained by forming an inorganic fiber cloth layer instead of the fluororesin layer containing no titanium oxide.

The antifouling film of the present invention can be produced, for example, as shown in FIG.

First, as shown in FIG. 2A, a carrier 4 is prepared. As the carrier, there is no particular limitation as long as it has heat resistance that does not cause deformation or the like even when heated at the time of forming a film such as a metal foil or a metal sheet, and can peel the film formed thereon. it can. Specific examples include a stainless steel foil and a polyimide film.

Then, a fluororesin dispersion is prepared and applied on the carrier 4. The concentration of the fluororesin in this dispersion is appropriately determined according to various factors, but is usually about 40 to 60% by weight. The type of fluororesin dispersion is not particularly limited, and PTFE, P
Aqueous dispersions such as FA and FEP are exemplified. In this aqueous dispersion, the particle size of the fluororesin is usually about 0.2 to
0.3 μm. The dispersion can be applied by, for example, a method of dipping the carrier into the dispersion and pulling it up, a method of spraying or brushing the dispersion, a method of casting the dispersion on the carrier, and the like. Next, the applied dispersion is heated to evaporate and remove the dispersion solvent, and the fluororesin is baked to form the fluororesin layer 12 on the carrier 4 as shown in FIG. 2B. This heating may be two-stage heating. For example, heating for removing the dispersion solvent may be performed, and then heating for firing the fluororesin may be performed.
The conditions for this heat treatment are appropriately determined depending on the types of the dispersion solvent and the fluororesin, the dispersion concentration, and the like. Note that the series of processes of application and heating of the dispersion can be repeatedly performed until the target fluororesin layer has a desired thickness.

On the other hand, a dispersion containing titanium oxide particles and a fluororesin is prepared. This dispersion usually has a fluororesin concentration of 40 to 60% by weight. Then, this dispersion is applied on the fluororesin layer 12, heated to remove the dispersion solvent by evaporation, and to sinter the fluororesin, as shown in FIG. 2 (C). The fluororesin layer 11 containing titanium oxide is formed. Ratio of the applied amount is the ratio of the thickness of the titanium oxide-containing fluorine resin layer is about 5 to 25 [mu] m, specifically, usually 1 to 100 g / m ^2, preferably 10 to 50 g / m ^2. The method of applying the dispersion and firing the fluororesin is the same as described above.

Then, as shown in FIG.
By peeling off and removing, the desired antifouling film 1 can be produced.

In this production example, the fluororesin dispersion was applied to the carrier to produce a fluororesin sheet, but the present invention is not limited to this. For example, a fluororesin sheet can be produced by compressing and molding a fluororesin molding powder into a block having a predetermined shape, firing this, and then cutting it into a sheet.
In addition, after blending the extrusion aid with the fluororesin fine powder and maturing, the mixture is molded into a predetermined shape by an extruder, further processed into a sheet by roll rolling or the like, and the auxiliary is extracted and removed. And a fluororesin sheet. This sheet is not fired, but may be heated and fired before use. In addition, depending on the purpose, these fluororesin sheets are made of carbon, graphite, glass fiber, bronze,
Molybdenum disulfide or the like may be blended.

Then, on the fluororesin sheet thus produced, a fluororesin layer containing titanium oxide particles is formed in the same manner as described above.

When an inorganic fiber cloth is used, a fluororesin layer containing titanium oxide particles is formed thereon in the same manner as described above. For indoor use or short-term use, the inorganic fiber cloth may be directly coated with a fluororesin dispersion, but when used for a long time, the inorganic fiber cloth may be coated with titanium oxide. It is preferable to apply a fluorine resin dispersion not containing at least once (with a thickness of 5 μm or more). When a glass fiber cloth is used, the smaller the filament diameter, the higher the strength. The filament diameter of glass fiber cloth is usually 3
１３13 μm. In addition, a commercially available glass fiber cloth usually has a sizing agent attached thereto, and this sizing agent may hinder the photocatalytic function of the titanium oxide particles. To remove the sizing agent. In addition, examples of the inorganic fiber cloth include a glass fiber cloth, a polycrystalline fiber cloth, a composite fiber cloth, and a metal fiber cloth. Examples of the material of the glass fiber cloth include E glass, S glass, fused quartz (SiO ₂ ), and the like.
Examples of the material type of the polycrystalline fiber cloth include alumina, zirconia, carbon, and boron nitride.
Examples of the material type of the composite fiber cloth include composite materials such as boron / tungsten (boron fiber), boron / fused quartz, boron carbide / boron / tungsten, and silicon carbide / tungsten. Examples of the material type of the metal fiber cloth include tungsten, molybdenum, a super heat-resistant nickel alloy, steel, beryllium, and stainless steel.
The basis weight of the inorganic fiber cloth varies depending on the type of the material and the like, but in the case of glass fiber cloth, it is in the range of 17 to 1760 g / m ² .

The titanium oxide used in the present invention is preferably an anatase type having an excellent photocatalytic function. The particle size of the titanium oxide particles is usually 0.007 to 0.5.
2 μm, and the compounding amount is as described above.

FIG. 3 is a sectional view showing another example of the structure of the antifouling film of the present invention. As shown, this film 1a
Is formed by forming a fluororesin layer 11 containing titanium oxide particles on both surfaces of a fluororesin sheet (layer) 12 serving as a base material. The thickness of the fluororesin sheet 12 is usually about 0.05 to 2.0 mm. The thickness of the titanium oxide-containing fluororesin layer 11 is usually in the range of about 0.005 to 0.05 mm.

FIG. 4 is a sectional view showing another example of the structure of the antifouling film of the present invention. As shown, this film 1
In b, a fluororesin layer 12 and a titanium oxide-containing fluororesin layer 11 are laminated on both surfaces of the inorganic fiber cloth layer 13 in this order. The thickness of the inorganic fiber cloth layer 13 is usually in a range of about 0.03 to 1.0 mm.
The thicknesses of the other layers are the same as those in FIG.
The fluororesin layer 12 also serves as a protective layer for the inorganic fiber cloth layer 13.

The antifouling film of the present invention thus obtained is applied, for example, by applying an adhesive or pressure-sensitive adhesive to the surface of the object to be protected and then bonding or adhering it by a method such as lamination. . At this time, as an additional effect of the titanium oxide particle-containing fluororesin layer, the amount of ultraviolet rays is reduced by the titanium oxide particles, so that improvement in weather resistance of the adhesive, the pressure-sensitive adhesive, and the roughened surface can be expected.

As described above, in the antifouling film of the present invention, it is preferable to improve the adhesion by performing a surface roughening treatment on the surface of the fluororesin layer containing no titanium oxide particles. As the surface roughening treatment, a known method such as a sputter etching treatment, a corona discharge treatment, a metal sodium treatment, and a plasma treatment can be employed. In particular, sputter etching is preferable because it has an effect on a fluororesin which is difficult to bond and does not cause coloring or the like. However, depending on the type of fluororesin, a corona discharge or the like can provide a sufficient effect similar to the sputter etching treatment. Then, printing or the like may be performed on the surface of the fluororesin layer subjected to the surface roughening treatment.

In the antifouling film of the present invention, it is preferable to provide an adhesive layer in advance on the surface opposite to the surface where the titanium oxide-containing fluororesin layer is located. This way,
The antifouling film can be used as a laminating film, which facilitates adhesion to an object to be protected. When the adhesive layer is formed on the fluororesin layer, it is preferable that the adhesive layer be formed after the surface of the fluororesin layer is roughened. In addition, examples of the adhesive include hot melt adhesives such as polyester and polyamide. The formation of the adhesive layer can be performed by coating or film lamination.

In the antifouling film of the present invention, a pressure-sensitive adhesive layer may be formed instead of the adhesive layer. This allows
The antifouling film of the present invention can be an adhesive tape, which can easily be freely deformed into an arbitrary shape, and can be easily attached to a hand residue or a portion where dirt easily adheres. When the pressure-sensitive adhesive layer is formed on the fluororesin layer, it is preferable to form the pressure-sensitive adhesive layer after performing a surface roughening treatment on the fluororesin layer. The pressure-sensitive adhesive includes, for example, an acrylic or silicone-based pressure-sensitive adhesive. Also, the formation of the adhesive layer
It can be carried out by performing coating or the like.

When the surface of the titanium oxide-containing fluororesin layer is exposed to light such as sunlight or fluorescent light, the antifouling film of the present invention develops a strong oxidizing power due to the photocatalytic reaction of the titanium oxide particles and adheres to the film surface. Organic matter is decomposed,
The inorganic particles that have adhered an organic substance as a binder lose the binder and can be easily removed by washing, wiping, or the like. In addition, persistent dirt such as oil stains and dirt can be similarly decomposed and removed by photocatalysis. And, the antifouling film of the present invention can be expected to exhibit antibacterial action by photocatalytic action as well as stain resistance by the titanium oxide particles contained therein.

[0039]

EXAMPLES Examples will be described below together with comparative examples.

(Example 1) A stainless steel foil having a thickness of 50 µm was used as a carrier, immersed in an aqueous dispersion having a PTFE concentration of 40% by weight, pulled up, and then heated at 110 ° C for 60 seconds to remove water. Then, the PTFE was baked by heating at 390 ° C. for 90 seconds to form a PTFE layer on the stainless steel foil. The thickness of this layer is 7
μm. Next, the stainless steel foil on which the PTFE layer is formed is immersed in an aqueous dispersion containing PTFE powder and titanium oxide particles and pulled up.
Heat at 110 ° C. for 60 seconds to remove water, then add
By heating at 90 ° C. for 90 seconds, the PTFE was baked to form a PTFE layer containing titanium oxide particles.
The immersion of the titanium oxide particles and the PTFE in the aqueous dispersion and the multi-stage heating were repeated once more, and then the stainless steel foil was peeled off and removed to obtain a PTFE layer containing the titanium oxide particles (having a thickness of 18 μm).
An antifouling film (25 μm in total thickness) in which a PTFE layer containing no titanium oxide was formed on one side of m).

The PTFE containing the above titanium oxide particles
The dispersion for forming the layer had a PTFE powder concentration of 60.
Anatase-type titanium oxide particles (manufactured by Ishihara Sangyo Co., Ltd., trade name: ST-4) are added to 100 parts by weight of a dispersion (manufactured by Asahi ICI Fluoropolymers, Fluon AD-1).
1) 40 parts by weight of 40 parts by weight of distilled water and 40 parts by weight of distilled water are dispersed while stirring, and 1% by weight based on the total weight of a silicone surfactant (L-77, manufactured by Nippon Unicar Co., Ltd.) is added with stirring. Was prepared. In the PTFE layer containing the titanium oxide particles, the weight ratio of the titanium oxide particles to the PTFE powder (titanium oxide particles: P
TFE powder) was 4: 6.

As a result of observing the surface of the thus obtained antifouling film on the PTFE layer side containing the titanium oxide particles with a scanning electron microscope, the titanium oxide particles were exposed on the surface.
Except for this part, it had a dense structure without holes.

Example 2 The same procedure as in Example 1 was carried out except that the amount of the titanium oxide particles was changed to 6.7 parts by weight, and one surface of the PTFE layer (18 μm thick) containing the titanium oxide particles was oxidized. An antifouling film (with a total thickness of 25 μm) on which a PTFE layer containing no titanium was formed was obtained. The weight ratio of the titanium oxide particles to the PTFE powder in the PTFE layer containing the titanium oxide particles (titanium oxide particles: PT
FE powder) was 1: 9.

Example 3 The amount of the titanium oxide particles was 1
An antifouling film in which a PTFE layer containing no titanium oxide was formed on one side of a PTFE layer containing titanium oxide particles (thickness: 18 μm) in the same manner as in Example 1 except that the amount was 40 parts by weight. ) Got. The titanium oxide particles of the PTFE layer containing the titanium oxide particles and PT
Weight ratio with FE powder (titanium oxide particles: PTFE powder)
Was 7: 3.

Comparative Example 1 A 50 μm-thick stainless steel foil was used as a carrier, which was immersed in an aqueous dispersion having a PTFE concentration of 40% by weight and pulled up.
By heating at 0 ° C. for 60 seconds to remove water, and then heating at 390 ° C. for 90 seconds, the PTFE is calcined to obtain PTFE.
An E layer was formed. The layer forming operation by immersion, lifting and heating in the dispersion is further repeated twice,
A PTFE film having a thickness of 23 μm was formed, and the stainless steel foil was peeled off and removed to obtain a PTFE film.

Examples 1, 2, and 3 obtained as described above
The antifouling film of Comparative Example 1 was exposed outdoors for 6 months to examine the stain resistance of the surface of the PTFE layer containing the titanium oxide particles. The results are shown in Table 1 below. The table also shows the adhesion between the titanium oxide particles and the PTFE layer. In the table, ◎ indicates that titanium oxide was not dropped off, and ○ indicates that titanium oxide was slightly dropped.

[0047]

[Table 1]

As can be seen from Table 1, the antifouling films of Examples 1 and 3 did not show any contamination, and the antifouling film of Example 2 showed a slight contamination, but it was compared with Comparative Example 1. , Its pollution was small. In contrast, the antifouling film of Comparative Example 1 was significantly contaminated. In the antifouling films of Example 1 and Example 2, the titanium oxide particles did not fall off, and in the antifouling film of Example 3, slight falling off of the titanium oxide particles was observed. In addition, it did not affect the stain resistance.

Example 4 The surface of the PTFE layer of the antifouling film obtained in Example 1, which did not contain titanium oxide particles, was subjected to sputter etching. This process was performed for 20 seconds under the conditions of an atmosphere pressure of 0.05 Torr and a discharge power of 30 W · sec / cm ² using an argon gas as an atmosphere gas.

In order to confirm the effect of the sputter etching treatment, the adhesive force of a commercially available pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name No. 31B) to the treated surface was measured.
It was 1.2 kg / 19 mm. The adhesion test was performed by pressing a pressure-sensitive adhesive tape on the treated surface with a 2 kg roller and then applying a 180 ° peeling method at a temperature of 25 ° C. and a tensile speed of 300 mm / min. PTFE not containing titanium oxide particles not subjected to the treatment
When a similar test was performed on the surface of the layer, the adhesive strength was found to be 0.1.
It was 1 kg / 19 mm.

(Example 5) In the antifouling film of Example 4, a solvent-based hot melt adhesive was applied to the surface of the sputter-etched PTFE layer containing no titanium oxide particles. This application was performed manually using an applicator. The dry coating thickness of the adhesive at this time was 15 μm. When the adhesive layer of the antifouling film and the steel sheet whose surface had been subjected to an adhesive treatment were heated and pressed using a laminator roll, the antifouling film was firmly adhered to the steel sheet.

Example 6 A silicone-based adhesive dissolved in a solvent was applied to the antifouling film of Example 4 which was adhered to the surface of the PTFE layer containing no titanium oxide particles. This coating was performed manually using a coater. At this time, the dry applied thickness of the adhesive was 30 μm. When this antifouling film was pressed with a 2 kg roller and bonded to a steel sheet whose surface had been subjected to an adhesive treatment via the pressure-sensitive adhesive layer, it adhered firmly to the steel sheet.

(Comparative Example 2) A PTF was prepared in the same manner as in Example 1.
The stainless steel foil was immersed in the dispersion containing the E powder and the titanium oxide particles, pulled up, and then heated twice. The layer forming operation was repeated twice to obtain a PTFE layer-only film containing titanium oxide particles having a thickness of 18 μm. . The surface of the film on the side of the stainless steel foil carrier was subjected to sputter etching in the same manner as in Example 4. Thereafter, an adhesive was applied to the treated surface in the same manner as in Example 5 to firmly adhere to the steel plate.

Comparative Example 3 In the same manner as in Comparative Example 2, a PT containing titanium oxide particles subjected to sputter etching treatment was used.
A film having only the FE layer was produced. Then, an adhesive was applied to the treated surface of the film in the same manner as in Example 6, and the film was firmly adhered to a steel plate. About the antifouling films of Examples 5 and 6 and Comparative Examples 2 and 3 thus produced,
A 6-month outdoor exposure test was performed with the sheet adhered to a steel sheet. The results are shown in Table 2 below.

[0055]

[Table 2]

From Table 2 above, in the antifouling film of Example 5, no contamination was observed on the surface of the PTFE layer containing the titanium oxide particles, and the antifouling film was peeled from the adhesive.
No floating was observed. Also, in the antifouling film of Example 6, no contamination was observed on the surface of the PTFE layer containing the titanium oxide particles, and no peeling or lifting of the antifouling film from the adhesive was observed. On the other hand, in the film of Comparative Example 2, no contamination was observed on the surface of the PTFE layer containing the titanium oxide particles, but there were portions where the film floated off the adhesive and peeled off. Comparative Example 3
In the film of No. 1, no contamination was observed on the surface of the PTFE layer containing the titanium oxide particles, but as in Comparative Example 2, there was a portion where the film floated off the adhesive and was peeled off.

Example 7 PT Obtained by Emulsion Polymerization
A paraffin-based lubricant was blended in an amount of 24% by weight in FE fine powder, and after aging, a round bar-shaped molded product was obtained by paste extrusion, and an unfired PTFE sheet having a thickness of 0.1 mm was obtained by calendering. Thereafter, the paraffin-based lubricant was extracted and removed with a solvent to obtain a PTFE sheet.

Next, PTFE powder and an anatase type photocatalyst
Unfired PTFE powder containing titanium oxide
Apply to both sides of the sheet and heat at 110 ° C for 60 seconds to remove moisture.
And then baking at 390 ° C. for 90 seconds
20 g / m ^TwoPTF containing titanium oxide
An intended antifouling film having an E layer was obtained.

The concentration of the dispersion containing the photocatalyst titanium oxide was set to 40% by weight, and one coating was applied to one side of the dispersion.
0 g / m ² was not exceeded. It is possible to apply more than 20 g / m ² on one side by adjusting the coating speed or concentration, but the surface condition tends to be rough, so that 20 g / m ² /
It is desirable to apply the coating amount of m ² or less in several applications.

The dispersion for forming the PTFE layer containing the above-mentioned photocatalytic titanium oxide has a PTFE powder concentration of 60% by weight.
Anatase type photocatalytic titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., trade name: ST) in 100 parts by weight of a dispersion (manufactured by Asahi ICI Fluoropolymers, trade name: Fluon AD-1)
-01) 40 parts by weight of distilled water and 40 parts by weight of distilled water are dispersed with stirring, and 1% by weight of a silicone surfactant based on the total weight (trade name L-77, manufactured by Nippon Unicar Co., Ltd.)
Was prepared by adding with stirring. The weight ratio between the photocatalyst titanium oxide and the PTFE in the PTFE layer containing the photocatalyst titanium oxide is 4: 6.

As a result of observing the surface of the outermost layer of the thus obtained antifouling film with a scanning electron microscope, it was found that the fine particles of titanium oxide photocatalyst had a dense structure with no pores exposed on the surface.

Next, the antifouling film was subjected to a test for decomposing odorous substances. That is, first, an antifouling film (5 cm × 5 cm) is placed in a closed container having an internal volume of 4 liters in which a black light is set, and 100 ppm of a malodorous substance, trimethylamine, is injected. The ultraviolet light of No. ² was applied to the antifouling film. Thirty minutes later, as a result of measuring the concentration of trimethylamine in the container using a gas chromatograph, the concentration was reduced to 8 ppm. 25pp without light
m. However, when this injection operation was repeated three times, the intensity decreased to 10 ppm in the case of light irradiation, but hardly decreased in the absence of light, and decreased only to 60 ppm.

Example 8 The same antifouling film as in Example 7 was stretched three times in the longitudinal direction by a roll stretching machine in a 350 ° C. atmosphere to obtain a film having a porosity of 45%. The antifouling film was measured for the decomposability of malodorous substances (trimethylamine) in the same manner as in Example 7, and it was found that 100 ppm of the film was injected and 2 ppm was reduced. 9p even when there is no light
pm. However, when this injection operation was repeated three times, the intensity was reduced to 4 ppm in the case of light irradiation, but hardly decreased in the absence of light, and decreased to only 45 ppm.

Example 9 A 0.1 mm thick glass cloth (KS1202J, manufactured by Kanebo Co., Ltd.) having a PTFE powder concentration of 60% by weight (Fluon AD-1, trade name, manufactured by Asahi ICI Fluoropolymers Co., Ltd.) ) Was applied to remove water at 100 ° C. for 90 seconds, and then baked by heating at 370 ° C. for 2 minutes. This operation was repeated to obtain a PTFE coated sheet having a coating rate of 200 g / m ² . A PTFE dispersion containing titanium oxide photocatalyst having the same composition as in Example 7 was applied to the surface of the sheet, and the sheet was baked at 370 ° C. by removing water by the same operation as described above.
Thus, an antifouling film having a titanium oxide-containing fluororesin layer having an adhesion ratio of 230 g / m ² was obtained. The antifouling film was measured for the decomposability of malodorous substances (trimethylamine) in the same manner as in Example 7, and as a result, 100 ppm
What was injected was reduced to 5 ppm. In the absence of light, it was reduced to 15 ppm. However, when this injection operation was repeated three times, the intensity was reduced to 7 ppm in the case of light irradiation, but hardly decreased in the absence of light, and decreased to only 55 ppm.

[0065]

As described above, in the antifouling film of the present invention, at least one of the fluororesin layer containing no titanium oxide particles and the inorganic fiber cloth layer is provided on one surface of the fluororesin layer containing the titanium oxide particles. Is formed. With this configuration, the titanium oxide-free fluororesin layer or the like can be used as an adhesive layer or pressure-sensitive adhesive layer formed when the antifouling film is attached to the surface of the object to be protected. Protects against the oxidizing effects of For this reason, the antifouling film of the present invention has excellent adhesiveness, and can cover and protect an object to be protected for a long time. In addition, the fluororesin layer or the like containing no titanium oxide ensures sufficient mechanical strength of the whole antifouling film. For this reason, in the antifouling film of the present invention, it is possible to mix a large amount of titanium oxide particles or to reduce the thickness of the fluororesin layer containing the particles, thereby ensuring a sufficient degree of exposure of titanium oxide. As a result, the antifouling film of the present invention exhibits excellent stain resistance.

Further, the antifouling film of the present invention can be produced by the production method of the present invention, and according to this production method, the titanium oxide particles are sufficiently exposed from the surface of the fluororesin layer. It becomes possible. For this reason,
The oxidizing power of the titanium oxide particles is sufficiently exhibited, and as a result,
The antifouling film manufactured by the manufacturing method of the present invention has excellent stain resistance.

When a fluororesin layer is formed as a reinforcing layer, it can be processed into various shapes, and the surface area can be increased by a stretching operation or the like. The contact area with the film is also increased, and a film having excellent antifouling properties can be obtained. For applications requiring strength, glass fibers such as glass cloth may be used.

Furthermore, if the antifouling film of the present invention is used for applications such as curtains and roll screens,
New functions such as antifouling property and antibacterial property can be added.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating an example of the configuration of an antifouling film of the present invention, and FIG. 1B is a cross-sectional view illustrating a state in which the antifouling film is adhered to an object to be protected. It is.

FIGS. 2A to 2D are cross-sectional views illustrating an example of a manufacturing process of the antifouling film of the present invention.

FIG. 3 is a sectional view showing a configuration of another embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antifouling film 2 Adhesive layer or adhesive layer 3 Protected object 11 Fluororesin layer containing titanium oxide particles 12 Fluororesin layer not containing titanium oxide particles 13 Inorganic fiber cloth layer

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[Procedure amendment]

[Submission date] August 19, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 5

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction contents]

[0056] Table 2 or, et al., In the antifouling film of Example 5, showed no contamination on the surface of the PTFE layer containing titanium oxide particles, peeling from the adhesive of the antifouling film, floating, etc. was observed Did not. Also, in the antifouling film of Example 6, no contamination was observed on the surface of the PTFE layer containing the titanium oxide particles, and no peeling or lifting of the antifouling film from the adhesive was observed. On the other hand, in the film of Comparative Example 2, no contamination was observed on the surface of the PTFE layer containing the titanium oxide particles, but there were portions where the film floated off the adhesive and peeled off. In the film of Comparative Example 3, no contamination was observed on the surface of the PTFE layer containing the titanium oxide particles, but as in Comparative Example 2, there was a portion where the film floated off the adhesive and was peeled off.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction contents]

When a fluororesin layer is formed as a reinforcing layer, it can be processed into various shapes, and the surface area can be increased by a stretching operation or the like. The contact area with the film is also increased, and a film having excellent antifouling properties can be obtained. In applications requiring strength, inorganic materials such as glass cloth
A fiber cloth or the like may be used.

Continuation of front page (72) Inventor Kenji Sato 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation

Claims (10)

[Claims] An antifouling film in which at least one of a fluororesin layer containing no titanium oxide particles and an inorganic fiber cloth layer is formed on one surface of a fluororesin layer containing titanium oxide particles. 2. The antifouling film according to claim 1, wherein the fluororesin layer containing the titanium oxide particles is non-porous. 3. The antifouling film according to claim 1, wherein the titanium oxide particles are exposed from the surface of the fluororesin layer. 4. The weight ratio between the titanium oxide particles and the fluororesin resin in the fluororesin layer containing the titanium oxide particles is as follows: titanium oxide particles: fluororesin = 1: 9 to 7: 3.
The antifouling film according to any one of claims 1 to 3, which is in the range of: 5. The weight ratio of titanium oxide particles to fluororesin resin in the fluororesin layer containing titanium oxide particles is as follows: titanium oxide particles: fluororesin resin = 3: 7 to 6: 4.
The antifouling film according to any one of claims 1 to 3, which is in the range of: 6. The antifouling film according to claim 1, wherein the surface of the fluororesin layer containing no titanium oxide particles is subjected to a roughening treatment to improve the adhesiveness. 7. The antifouling film according to claim 1, wherein an adhesive layer is formed on a surface opposite to a surface on which the fluororesin layer containing the titanium oxide particles is located. 8. The antifouling film according to claim 1, wherein an adhesive layer is formed on a surface opposite to a surface on which the fluororesin layer containing the titanium oxide particles is located. 9. A step of applying a dispersion containing a fluororesin and titanium oxide particles to at least one surface of the fluororesin sheet and the inorganic fiber cloth, a step of evaporating and removing a dispersion solvent in the dispersion, Baking the fluororesin to form a fluororesin layer containing titanium oxide particles. 10. The method for producing an antifouling film according to claim 9, wherein the weight ratio of the titanium oxide particles to the fluororesin is in the range of titanium oxide particles: fluororesin = 1: 9 to 6: 4.