JP2012086397A - Self-cleaning stain preventive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-cleaning stain preventive sheet, in a film material incidental with a photocatalytic functional layer, which holds the photocatalytic layer while exhibiting a stain removing effect by the decomposition action of the photocatalytic layer, and can maintain a stain preventive effect over a long period from the start of the use of the film material thereby.SOLUTION: In the flexible sheet having a photocatalytic functional layer(s) on the one or more faces of a sheet-like base material, the photocatalytic functional layer is formed from a sea-island fine structure composed of a photocatalytic particle-containing region and a photocatalytic particle non-containing region. In the sea-island fine structure, the sea component is made into the photocatalytic particle-containing region formed from a synthetic resin (A) containing photocatalytic particles, the island component is made into the photocatalytic particle non-containing region formed from a synthetic resin (B) not containing photocatalytic particles, further, the synthetic resin (A) is made refractory by photocatalytic activity, also, the synthetic resin (B) is made degradative to photocatalytic activity, and further, a peroxide is incorporated into the island component.

Description

  The present invention relates to a self-cleaning antifouling sheet. More specifically, the present invention is excellent in self-cleaning antifouling and durability, and is suitable for industrial use such as medium and large tents, members for membrane structure buildings such as tent warehouses, outdoor large signboards, store-integrated interior lighting signs, etc. The present invention relates to a flexible sheet excellent in self-cleaning antifouling used suitably as a material.

  A laminated sheet formed by forming a waterproof layer made of a thermoplastic resin on one side or more of a fiber cloth as a base cloth, so-called tarpaulins and canvases are building members such as sunshade tents, medium and large tents, tent warehouses, and building curing sheets, In addition, it is used in the field of industrial material sheets such as truck hoods, signboards for signboards, and flexible containers. Recently, in the permanent use of membrane structures such as sunshade tents, medium- and large-sized tents, and tent warehouses, photocatalytic antifouling technology as an added value accompanying the improvement of the service life has attracted attention. Various film materials with such a photocatalyst layer have been proposed. (Patent Documents 1 to 3)

  These film materials with a photocatalyst layer are intended to decompose a dirt component with a photocatalyst by providing a photocatalyst layer on the surface of the film material and to wash this residue by rain. Depending on the adhesion state, a long lead time was required until the removal effect was manifested. As a method for shortening the lead time, there has been proposed removal of dirt by weathering the photocatalyst layer. In this method, the surface of the photocatalyst layer is intentionally decomposed and controlled, and the surface layer is dropped together with the attached dirt, so that a new surface is always exposed to maintain the aesthetic appearance. (Patent Document 4)

  However, these methods involve the self-decay of the photocatalyst layer, and therefore, there is a problem that the antifouling effect disappears rapidly after a certain period of use. Therefore, it is possible to maintain the antifouling effect for a long period of time from the start of use of the membrane material if the antifouling layer can be retained while exhibiting the effect of removing the dirt due to the decomposition action of the antifouling layer. It becomes.

JP 2001-098464 A JP 2001-105535 A JP 2001-113640 A JP 2005-271490 A

  The present invention provides a film material with a photocatalyst functional layer that retains the photocatalyst layer while exhibiting the effect of removing dirt due to the decomposition action of the photocatalyst layer, thereby preventing antifouling over a long period from the start of use of the film material. It is intended to provide a self-cleaning antifouling sheet that can sustain the effect.

  In order to solve the above problems, in a flexible sheet having a photocatalytic functional layer on one or more sides of a sheet-like substrate, the photocatalytic functional layer is formed with a sea-island microstructure comprising a photocatalyst particle-containing region and a photocatalyst particle-free region. In this sea-island microstructure, the sea component was formed from a synthetic resin (B) containing no photocatalyst particles, with the sea component being a photocatalyst particle-containing region formed from a synthetic resin (A) containing photocatalyst particles. As a non-photocatalyst particle-containing region, the synthetic resin (A) is hardly decomposable due to photocatalytic activity, and the synthetic resin (B) is decomposable with respect to photocatalytic activity. By containing it, the photocatalyst layer is retained while exhibiting the effect of removing dirt due to the decomposition action of the photocatalyst layer, thereby maintaining the antifouling effect for a long period from the start of use of the film material. This has led to the completion of the present invention out.

  That is, the self-cleaning antifouling sheet of the present invention is a flexible sheet having a photocatalytic functional layer on one or more surfaces of a sheet-like substrate, and the photocatalytic functional layer is composed of a photocatalyst particle-containing region and a photocatalyst particle-free region. The sea island microstructure is formed, and in this sea island microstructure, the sea component is the photocatalyst particle-containing region formed from the synthetic resin (A) containing the photocatalyst particles, and the island component does not contain the photocatalyst particles. The photocatalyst particle-free region formed by (2), the synthetic resin (A) is hardly decomposable due to photocatalytic activity, and the synthetic resin (B) is degradable with respect to photocatalytic activity. It is preferable. As a result, the self-cleaning antifouling sheet of the present invention retains the photocatalyst layer while demonstrating the dirt removing effect due to the decomposition action of the photocatalyst layer, thereby maintaining the antifouling effect over a long period from the start of use of the film material. Make it possible.

  In the self-cleaning antifouling sheet of the present invention, it is preferable that the island component further contains 0.001 to 1% by mass of a peroxide with respect to the synthetic resin (B). As a result, the self-cleaning antifouling sheet of the present invention can exhibit an effective self-cleaning antifouling effect from the beginning of use since the decomposition of the island components is accelerated.

  In the self-cleaning antifouling sheet of the present invention, the sheet-like base material is preferably a fiber composite laminate including a fiber fabric as a core material. Thus, the self-cleaning antifouling sheet of the present invention can be suitably used for industrial materials such as medium- and large-sized tents, members for membrane-structured buildings such as tent warehouses, outdoor large signboards, and store-integrated interior lighting signs. it can.

  By using the self-cleaning antifouling sheet of the present invention for industrial materials such as medium- and large-sized tents, membrane structure building materials such as tent warehouses, outdoor large signboards, and store-integrated interior lighting signs, the photocatalytic layer is decomposed. While retaining the photocatalyst layer while demonstrating the effect of removing dirt due to the action, the antifouling effect can be maintained over a long period of time from the start of use of the film material. Maintenance-free and beautifully maintained.

The figure which shows an example of sectional drawing of the self-cleaning antifouling sheet of this invention The figure which shows an example of the sea-island microstructure of the self-cleaning antifouling sheet of this invention Sectional drawing which shows an example of the self-cleaning antifouling sheet of this invention (initial dirt adhesion state) The figure which shows the concept of the erosion process of the sea-island microstructure of the photocatalytic functional layer of the self-cleaning antifouling sheet of the present invention

  The self-cleaning antifouling sheet of the present invention is a flexible sheet having a photocatalytic functional layer on one or more surfaces of a sheet-like base material, and the photocatalytic functional layer is composed of a photocatalyst particle-containing region and a photocatalyst particle-free region. In this sea-island microstructure, the sea component is a photocatalyst particle-containing region formed from a synthetic resin (A) containing photocatalyst particles, and the island component is formed by a synthetic resin (B) that does not contain photocatalyst particles. It is preferable that the synthetic resin (A) is hardly decomposable due to photocatalytic activity, and the synthetic resin (B) is degradable with respect to photocatalytic activity. The sea-island microstructure for achieving the present invention is formed by fine dispersion by an incompatible blend of the synthetic resin (A) and the synthetic resin (B), and a composition of the synthetic resin (A) containing photocatalyst particles It can obtain by mixing with the composition by the synthetic resin (B) which does not contain a photocatalyst particle.

  The sheet-like substrate used for the self-cleaning antifouling sheet of the present invention is a thermoplastic resin film having a thickness of 0.1 to 0.3 mm (for example, soft to semi-rigid vinyl chloride resin, polyethylene, polypropylene, polyester, polyamide, polyurethane, etc.) Or a thermoplastic resin sheet having a thickness of 0.3 to 1.0 mm (for example, soft to semi-rigid vinyl chloride resin, vinyl chloride elastomer, polyolefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, etc.) be able to. In the self-cleaning antifouling sheet of the present invention, it is particularly preferable that the sheet-like substrate is a fiber composite laminate including a fiber fabric as a core material because of excellent tensile strength and dimensional stability. The fiber composite laminate used in the present invention is a mode in which a fiber cloth is impregnated (dipped) with a thermoplastic resin and solidified, a mode in which a thermoplastic resin is applied to the fiber cloth (coating) and solidified, and a fiber cloth is heated. Examples include a mode in which a plastic resin film or sheet is laminated with a thermal laminate or an adhesive, and a sheet having a thickness of 0.3 to 1.0 mm obtained by a combination thereof. In particular, a fiber fabric is impregnated with a thermoplastic resin. An embodiment in which a resin film is formed on both sides of the fiber fabric in a solidified form, a form in which a thermoplastic resin film is thermally laminated on the fiber cloth, a member for a membrane structure building such as a medium-to-large tent, a tent warehouse, and the like It is preferable for applications such as sign sheets for outdoor large signboards and store-integrated interior lighting signs.

  Any of a woven fabric, a knitted fabric, and a nonwoven fabric may be sufficient as the fiber fabric used for a sheet-like base material. Examples of the woven fabric include known woven fabrics such as plain weave, twill weave, satin weave and imitation weave. Of these, plain weave fabric is preferable because of excellent balance of the physical properties of the resulting self-cleaning antifouling sheet. The woven fabric is woven with warps and wefts, and includes a warp in which a large number of inter-gap gaps are arranged in parallel and a plurality of wefts in which a large number of inter-gap gaps are arranged in parallel. It is either a woven fabric with a void (as a guideline, a thread driving density of 5 to 30 yarns / inch) or a high-density woven fabric with a porosity of less than 5% (as a guideline, a yarn driving density of 30 to 80 yarns / inch). May be. As for the proper use of these, the open woven fabric is suitable for a core material for thermal lamination of a thermoplastic resin film, and the high-density woven fabric is suitable for a core material for impregnation processing or coating processing with a thermoplastic resin. Further, the fiber fabric may be optionally subjected to a known water repellent treatment for preventing rain from permeating and a known flameproofing treatment for imparting self-extinguishing properties when flaming. Good.

  Examples of the fiber yarn constituting the fiber fabric used for the sheet-like substrate include monofilament, multifilament, and short fiber spun yarn. These include kenaf fiber, cotton fiber, polypropylene fiber, polyethylene fiber, polyester fiber, and nylon. Examples thereof include fibers, vinylon fibers, acrylic fibers, aromatic polymer fibers, aromatic heterocyclic polymer fibers, glass fibers, silica fibers, alumina fibers, and carbon fibers, and blended fibers thereof. The fiber fabric used in the present invention is preferably a polyester multifilament yarn fiber (particularly PET fiber or PEN fiber) having 3 to 300 filaments and a fineness of 138 to 2223 dtex (decitex), particularly 277 to 1112 dtex.

  In the self-cleaning antifouling sheet of the present invention, the photocatalyst functional layer forms a sea-island microstructure composed of a photocatalyst particle-containing region and a photocatalyst particle-free region, and in this sea-island microstructure, a synthetic resin (A ) Is a photocatalyst particle-containing region formed from the synthetic resin (B) in which the island component does not contain photocatalyst particles. Such a sea-island microstructure is formed by a melt-mixing of two types of synthetic resins, or a synthetic resin incompatible pair consisting of a stirred mixture of two types of liquid synthetic resins. It is preferable that the photocatalytic functional layer has a thickness of 0.01 to 0.25 mm, particularly 0.02 to 0.1 mm. If the thickness of the photocatalytic functional layer is 0.01 mm or less, the long-term sustainability of the sheet self-cleaning antifouling may be insufficient.

  In the present invention, the photocatalytic functional layer is a synthetic resin incompatible pair composed of a mixture of two types of synthetic resins, and there is no limitation on the combination of synthetic resins as long as they are incompatible. Examples of the synthetic resin (A) used in the present invention are fluorine-containing copolymer resins (acryl-vinylidene fluoride copolymer, silicon-vinylidene fluoride graft copolymer, urethane-vinylidene fluoride graft copolymer, Acrylic-urethane-vinylidene fluoride graft copolymer, vinylidene fluoride resin, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene Copolymer, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene / tetrafluoroethylene, polychlorotrifluoroethylene copolymer, ethylene -Chlorotrifluor Examples of synthetic resins (B) such as ethylene copolymer), silicone resin, silicone rubber, polycarbonate, polyamide, polyether, polyesteramide, polyphenylene sulfide, polyether ester, and vinyl ester resin are vinyl chloride resin, soft chloride Vinyl resin, olefin resin (PE, PP, etc.), olefin copolymer resin, urethane resin, urethane copolymer resin, vinyl acetate resin, vinyl acetate copolymer resin, styrene resin, styrene copolymer resin , Polyester resins (PET, PEN, PBT, etc.), polyester copolymer resins, etc., which are incompatible pairs selected from these groups (A) and (B).

  These synthetic resin immiscible pairs exhibit phase separability and particularly preferably have a sea-island microstructure. In this sea-island microstructure, the sea component and the island component are composed of different types of resins. In the present invention, the sea component is a photocatalyst particle-containing region formed from a synthetic resin (A) containing photocatalyst particles. This is a region containing no photocatalyst particles formed by the synthetic resin (B) containing no photocatalyst particles. The ratio of the synthetic resin (A) constituting the island component is 10 to 70% by volume (preferably 20 to 50% by volume) with respect to the volume of the synthetic resin resin (B) constituting the sea component, and is based on the entire photocatalytic functional layer. The island component content is 9 to 41.1% by volume (preferably 16.6 to 33.3% by volume). If the island component content relative to the entire photocatalytic functional layer is less than 9% by volume, the antifouling effect of the resulting sheet may be insufficient. If the island component content exceeds 41.1% by volume, the sea-island microstructure balance may be reversed.

  In the above-mentioned sea-island microstructure, the synthetic resin (A) is hardly decomposable due to photocatalytic activity, and the synthetic resin (B) is degradable to photocatalytic activity, that is, the sea component is hardly decomposable. However, the island component is preferably degradable. The shape of the island component is a sphere, a distorted sphere, a meteorite shape, a rugby ball shape, or the like. The average particle size of the island components is 0.05 to 25 μm, and 0.5 to 10 μm is particularly preferable. When the size of the island component is larger than 25 μm, it takes time to decompose the island component, and dust tends to accumulate in the erosion traces of the island component, so that the antifouling effect of the obtained sheet may be insufficient.

  In the present invention, the photocatalytic functional layer has a sea-island microstructure composed of an incompatible mixture of two types of synthetic resins, and only the sea component contains photocatalyst particles in the sea-island microstructure. Since only the sea component contains the photocatalyst particles, the photocatalyst particles are kneaded or stirred into the synthetic resin (A) on the side of forming the sea component out of the two types of synthetic resins constituting the synthetic resin incompatible couple. To form a sea-island microstructure consisting of a photocatalyst particle-containing region and a photocatalyst particle-free region by mixing the synthetic resin (A) containing photocatalyst particles and the synthetic resin (B) containing no photocatalyst particles. Can do. Since the synthetic resin (A) and the synthetic resin (B) are incompatible, the photocatalyst particles contained in the synthetic resin (A) are not taken into the synthetic resin (B) even in the case of excessive mixing. Thus, a photocatalytic functional layer having a sea-island microstructure essential for the self-cleaning antifouling sheet of the present invention can be obtained.

The photocatalyst particles to be contained in the sea component are titanium oxide (TiO ₂ ), titanium peroxide (peroxotitanic acid), zinc oxide (ZnO), tin oxide (SnO ₂ ), strontium titanate (SrTiO ₃ ), tungsten oxide (WO ₃ ), bismuth oxide (Bi ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), and these photocatalytic materials are doped with metals and metal oxides such as Pt, Rh, RuO ₂ , Nb, Cu, Sn, and NiO And at least one selected from those having enhanced photocatalytic activity. Also, inorganic porous fine particles carrying these photocatalytic substances can be used. Specifically, the inorganic porous fine particles are silica, zeolite, titanium zeolite, zirconium phosphate, calcium phosphate, zinc calcium phosphate, hydrotalcite having an average primary particle diameter of 0.01 to 10 μm, particularly 0.05 to 5 μm. Hydroxyapatite, silica alumina, calcium silicate, magnesium silicate aluminate, diatomaceous earth, and the like, which are composite particles carrying photocatalyst particles in these porous materials. The photocatalyst particles used in the present invention are particularly preferably titanium oxide, and any of anatase type, rutile type and brookite type can be used. Photocatalytic activity obtained by partially coating the surface of titanium oxide particles having photocatalytic activity with inorganic compounds such as silica, zirconium phosphate, calcium phosphate, zinc calcium phosphate, hydroxyapatite, silica alumina, calcium silicate, and magnesium aluminate silicate. Control type titanium oxide composite particles are particularly preferred. Content of these photocatalyst particles is 0.5-30 volume% with respect to the volume of the whole sea component area | region, ie, the volume of a synthetic resin (A), Preferably it is 1-15 volume%.

  In addition, the photocatalytic functional layer in the present invention is formed on the synthetic resin (B) for the purpose of controlling the degree of erosion of the sea component that is the photocatalyst particle-containing region, that is, the synthetic resin (B) in which the synthetic resin (A) is an island component. It is preferable to add a filler. Examples of the filler include metal oxides, metal hydroxides, metal composite oxides, metal composite hydroxides, and the like. Specifically, these include aluminum oxide, magnesium oxide, titanium oxide, zinc oxide, zirconium oxide, and oxide. Metal oxides such as antimony and silicon oxide (silica), and metal complex oxides such as zinc borate, aluminum borate, potassium titanate and zirconium-antimony, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, etc. And metal composite hydroxides such as dolomite, hydrotalcite, and borax, and other examples include barium sulfate, calcium carbonate, talc, clay, montmorillonite, and bentonite. The particle diameter of these fillers is preferably 0.01 to 10 μm.

  In the present invention, the photocatalytic functional layer is used to control the degree of erosion of the sea component that is the photocatalyst particle-containing region, that is, the synthetic resin (B) in which the synthetic resin (A) is an island component. It is preferable to add 0.001 to 1 mass% of a peroxide. The peroxide is preferably an organic compound having an —O—O— bond, which decomposes by heating or the action of a decomposition accelerator to generate free radicals. By this free radical attacking the molecular chain of the synthetic resin (A), the erosion of the synthetic resin (A) due to the photocatalytic activity can be further accelerated. Specific examples of the organic peroxide include hydroperoxides such as diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide; 2-t-butylperoxyisopropyl) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-hexyl peroxide , Di-tert-butyl peroxide, dialkyl peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3; diisobutyryl peroxide, di (3,5,5-trimethyl) Hexanonyl) peroxide, dilauroyl peroxide, disuccinic acid peroxide Diacyl peroxides such as dibenzoyl peroxide, di (3-methylbenzoyl) peroxide, benzoyl (3-methylbenzoyl) peroxide, di (4-methylbenzoyl) peroxide; methyl ethyl ketone peroxide, cyclohexane peroxide, acetylacetone peroxide, etc. Ketone peroxide; and the like. These organic peroxides may be used in combination of two or more. Examples of inorganic peroxides include sodium peroxide, potassium peroxide, barium peroxide, sodium percarbonate, potassium percarbonate, and barium percarbonate. These may be used in combination of two or more.

  Examples of the method for providing the photocatalytic functional layer on the sheet-like substrate in the present invention include, for example, a resin incompatible mixture dispersed in an organic solvent, a resin emulsion (latex) incompatible mixture, and a resin dispersion incompatible mixture. , Paste sol incompatible mixture mainly composed of polyvinyl chloride resin, incompatible mixture mainly composed of thermosetting resin, etc., using known coating methods such as dipping (double-sided processing on sheet-like substrate) ) And coating (single-sided processing or double-sided processing on a sheet-like substrate). Also, a film or sheet of 0.01 to 0.25 mm, preferably 0.05 to 1.0 mm, made of an incompatible thermoplastic mixture, formed by calender molding or T-die extrusion method on a sheet-like substrate, is used as an adhesive. And a method of laminating via heat laminating, or a combination of these coating and laminating.

  Further, in the present invention, a synthetic resin (A) group which is difficult to be decomposed by photocatalyst particles and has a film forming ability, and further, polysilazane, an organic silicate compound, and an organic silicate compound are provided between the photocatalytic functional layer and the sheet-like substrate. A barrier layer having a thickness of 0.005 to 0.1 mm is provided, comprising at least one component of a silicon compound condensate such as a hydrolyzate (silanol group-containing silane compound) of It is preferable.

  With respect to the self-cleaning antifouling sheet of the present invention, the flexible sheet of FIG. 1 will be described as an example. A flexible sheet (1) in FIG. 1 includes a fiber composite laminate (2-3) including a fiber fabric (2-1) as a core material as a sheet-like substrate (2), and this fiber composite laminate (2 -3) is obtained by laminating a thermoplastic resin layer (2-2) on the entire surface of both sides of the fiber fabric (2-1). The photocatalytic functional layer (3) is provided on the entire surface of one side of the fiber composite laminate (2-3).

  FIG. 2 shows the sea-island microstructure of the photocatalytic functional layer (3) of the self-cleaning antifouling sheet (1) of the present invention. The photocatalyst functional layer (3) forms a sea-island microstructure comprising a photocatalyst particle non-containing region (3-1) and a photocatalyst particle-containing region (3-2). In this sea-island microstructure, the island component (3-1 -A) shows the photocatalyst particle non-containing region (3-1) formed from the synthetic resin (B) not containing the photocatalyst particles (4), and the sea component (3-2-b) shows the photocatalyst particles (4). The photocatalyst particle containing region (3-1) formed by the synthetic resin (A) to be contained is shown.

  FIG. 3 shows a cross-sectional view (initial dirt adhesion state) showing an example of the self-cleaning antifouling sheet of the present invention. FIG. 4 shows the concept of the dirt removal process by the erosion of the sea-island microstructure of the photocatalytic functional layer (3) of the self-cleaning antifouling sheet (1) of the present invention. The photocatalyst particle non-containing region (3-1) formed from the synthetic resin (B) that does not contain the photocatalyst particle (4) that is the island component (3-1-a) is a sea component (3-2-b). It disappears at a moderate rate due to erosion due to catalytic decomposition by the photocatalyst particle-containing region (3-2) formed by the synthetic resin (A) containing a certain photocatalyst particle (4), and on the surface of the photocatalyst functional layer (3) This shows that the photocatalyst particle-containing region (3-2) formed by the synthetic resin (A) containing the photocatalyst particle (4) which is the sea component (3-2-b) remains. Although not shown in FIG. 4, the photocatalyst particle containing region (3-2) which is the sea component (3-2-b) is also a photocatalyst particle non-containing region (3-3) which is a further island component (3-1-a). It disappears with erosion at a moderate rate due to catalytic decomposition of -1).

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In the following Examples and Comparative Examples, the following fiber composite laminates including a fiber fabric as a core material as a sheet-like substrate were used. The dimensions of the sheet-like substrate were warp (the warp direction of the fiber fabric) 45 cm × weft (the weft direction of the fiber fabric) 30 cm, and the same sheet-like substrate was used in all the examples and comparative examples.
<Sheet substrate>
Plain woven fabric using 555 dtex multifilament made of polyester (PET) (density: warp (warp) 23 / inch x weft (weft) 23 / inch: mass 100 g / m ² : meshing degree 26%) As a fabric, a PVC film having a thickness of 0.18 mm made of the following composition containing a soft vinyl chloride resin is bridge-laminated by a thermocompression bonding method on each of the front and back surfaces of the fiber fabric, and the thickness is 0.44 mm and the mass is 528 g / mass. A sheet-like substrate of m ² was obtained. Bridge lamination means that PVC films placed on the front and back surfaces are heat-sealed and bonded at a temperature equal to or higher than the melting point of the PVC film through the cutouts of the fiber fabric, and at the same time, are well adhered or bonded to the fiber fabric. Thermal lamination method. The following surface treatment layer was formed on the surface (photocatalyst functional layer forming side) of the obtained sheet-like substrate. The surface treatment layer was uniformly applied at 12 g / m ² (wet) by 80 mesh gravure coating to form an acrylic resin layer having a solid content adhesion amount of 3.6 g / m ² . This surface treatment layer plays the role of diffusion migration and volatilization prevention of the soft vinyl chloride resin compound and assisting adhesion with the photocatalytic functional layer.

<Soft vinyl chloride resin composition>
100 parts by mass of straight vinyl chloride resin (P = 1050)
DOP (plasticizer) 30 parts by mass
Chlorinated n-paraffin (plasticizer) 10 parts by mass
Adipic acid polyester (plasticizer) 30 parts by mass
Epoxidized soybean oil (stabilizer) 4 parts by mass
Ba-Zn composite stabilizer 2 parts by mass
Rutile type titanium oxide (colorant) 5 parts by mass
Organic antifungal agent (OBPA) 0.2 parts by mass
UV absorber 0.3 parts by mass
Antioxidant 0.1 part by mass <Coating liquid for surface treatment layer formation>
Product name: Sony Bond SC-474: Sony Chemical Corporation: Acrylic copolymer resin
(Solid content 30% by mass) 100 parts by mass

Subsequently, the photocatalyst functional layers 1 to 3 were formed on the surface treatment layer, and self-cleaning antifouling sheet examples 1 to 3 of the present invention were obtained.

<Evaluation of antifouling properties>
The obtained sheet is exposed outdoors for 12 months at the installation angles of 30 ° and 90 ° (vertical) facing south. The presence or absence of rain streak on the vertical surface and the degree of contamination on the 30 ° surface are initially (blank). And ΔE value (JIS Z-8729). For color difference measurement, an optical color difference meter (JP7200F) manufactured by JUKI Corporation was used. If the ΔE value exceeds 3.0, it is determined that the self-cleaning property is poor.
* Outdoor exhibition started in October in Soka City, Saitama Prefecture.
ΔE = 0 to 1.9: 1 = Good without contamination. The initial state is maintained.
ΔE = 2 to 2.9: 2 = slightly dirty but no problem in appearance.
ΔE = 3 to 3.9: 3 = dirt adhesion, rain stripes are conspicuous.
ΔE = 4 or more: 4 = Dirty and rain streaks are severe, and the appearance is hindered.

[Example 1]
The vinyl chloride resin mixture of the following formulation 2 is added to the vinylidene fluoride resin mixture of the following formulation 1 (containing photocatalyst particles) and blended by adding 20% by mass with respect to the mass of the vinylidene fluoride resin alone, and the vinyl chloride resin is uniformly dispersed. A liquid of the incompatible resin mixture 1 was obtained. The liquid of this incompatible resin mixture 1 is wet-coated on the surface treatment layer of the sheet-like base material made of acrylic resin, and this coating film is blown dry at 180 ° C. to form a photocatalytic function having a coating thickness of 0.05 mm. Layer 1 was formed. When the photocatalytic functional layer 1 was observed with a microscope, the vinyl chloride resin constituted an island component free of photocatalyst particles, and the vinylidene fluoride resin constituted a sea component containing photocatalyst particles. As a result of exposing this sheet to the outdoors for 12 months and observing the soiled state, ΔE was an evaluation 1 level of 0.6.
[Incompatible resin mixture 1 for forming photocatalytic functional layer 1]
<Formulation 1>
100 parts by mass of vinylidene fluoride resin
8 parts by mass of photocatalytic titanium oxide
(Partial coating with surface coverage of 4 to 10% by inorganic oxide)
400 parts by weight of methyl ethyl ketone (solvent) <Formulation 2>
100 parts by mass of vinyl chloride resin (degree of polymerization 1300)
Ba-Zn composite stabilizer 2 parts by mass
10 parts by mass of calcium carbonate (average particle size 1 μm)
Organic peroxide (dicumyl peroxide) 0.03 parts by mass

[Example 2]
To the vinylidene fluoride resin mixture of the following formulation 3 (containing photocatalyst particles), 20% by mass of the soft vinyl chloride resin mixture of the following formulation 4 is added with respect to the mass of the vinylidene fluoride resin alone, and heated and melt blended at 180 ° C. An incompatible resin mixture 2 compound in which a soft vinyl chloride resin was uniformly dispersed was obtained. This incompatible resin mixture 2 compound was rolled with a calender device set at 180 ° C. to obtain a film having a thickness of 0.08 mm. This film was heat-laminated and laminated at 170 ° C. on the surface treatment layer of the sheet-like substrate made of acrylic resin. When this photocatalytic functional layer 2 was observed with a microscope, the soft vinyl chloride resin constituted an island component free of photocatalyst particles, and the vinylidene fluoride resin constituted a sea component containing photocatalyst particles. As a result of exposing this sheet outdoors for 12 months and observing the soiled state, ΔE was an evaluation 1 level of 0.9.
[Incompatible resin mixture 2 for forming photocatalytic functional layer 2]
<Formulation 3>
100 parts by mass of vinylidene fluoride resin
8 parts by mass of photocatalytic titanium oxide
(Partial coating with surface coverage of 4 to 10% by inorganic oxide)
<Formulation 4>
100 parts by mass of vinyl chloride resin (degree of polymerization 1300)
DOP (plasticizer) 30 parts by mass
Adipic acid polyester (plasticizer) 30 parts by mass
Epoxidized soybean oil (stabilizer) 4 parts by mass
Ba-Zn composite stabilizer 2 parts by mass
10 parts by mass of calcium carbonate (average particle size 1 μm)
Organic peroxide (dicumyl peroxide) 0.03 parts by mass

[Example 3]
A non-phase in which a soft vinyl chloride resin is uniformly dispersed by adding 20% by mass of the soft vinyl chloride resin mixture of Formula 4 to the silicone resin mixture of Formula 5 (containing photocatalyst particles) with respect to the mass of the silicone resin alone. A solution of the molten resin mixture 3 was obtained. The liquid of this incompatible resin mixture 3 is wet-coated on the surface-treated layer of the sheet-like substrate made of acrylic resin, and this coating film is blown dry at 180 ° C. to form a photocatalytic function having a coating thickness of 0.05 mm. Layer 3 was formed. When this photocatalyst functional layer 3 was observed with a microscope, the soft vinyl chloride resin constituted an island component not containing photocatalyst particles, and the silicone resin constituted a sea component containing photocatalyst particles. As a result of exposing this sheet to the outdoors for 12 months and observing the soiled state, ΔE was an evaluation 1 level of 1.3.
[Incompatible resin mixture 3 for forming photocatalytic functional layer 3]
<Formulation 5>
50 parts by weight of two-component addition reaction curable silicone resin
(Product name: Shirasukon RTV4086A
: Dow Corning Asia)
50 parts by weight of two-component addition reaction curable silicone resin
(Product name: Shirasukon RTV4086B
: Dow Corning Asia)
8 parts by mass of photocatalytic titanium oxide
(Partial coating with surface coverage of 4 to 10% by inorganic oxide)
100 parts by mass of methyl ethyl ketone (solvent)

[Example 4]
Incompatibility in which the polyurethane resin mixture of Formulation 6 is added to the vinylidene fluoride resin mixture of Formulation 1 (containing photocatalyst particles) and blended by adding 20% by mass to the mass of the vinylidene fluoride resin alone, and the polyurethane resin is uniformly dispersed. A liquid of the resin mixture 4 was obtained. The liquid of this incompatible resin mixture 4 is wet-coated on the surface treatment layer of the sheet-like base material made of acrylic resin, and this coating film is blown dry at 180 ° C. to form a photocatalytic function having a coating thickness of 0.05 mm. Layer 4 was formed. When this photocatalyst functional layer 4 was observed with a microscope, the polyurethane resin constituted an island component not containing photocatalyst particles, and the vinylidene fluoride resin constituted the sea component containing photocatalyst particles. As a result of exposing this sheet to the outdoors for 12 months and observing the soiled state, ΔE was an evaluation 1 level of 1.0.
[Incompatible resin mixture 4 for forming photocatalytic functional layer 4]
<Formulation 6>
100 parts by mass of polyurethane resin (ester)
8 parts by mass of photocatalytic titanium oxide
(Partial coating with surface coverage of 4 to 10% by inorganic oxide)
10 parts by mass of calcium carbonate (average particle size 1 μm)
Organic peroxide (dicumyl peroxide) 0.03 parts by mass

As a result of the outdoor exposure test for one year, the sheets of Examples 1 to 4 were all in the range of ΔE = 0 to 1.9, and had sufficient self-cleaning antifouling effects as antifouling sheets. In particular, by containing 0.001 to 1% by mass of organic peroxide (dicumyl peroxide) in the island component of the photocatalytic functional layer, the decomposition rate of the island component is accelerated, and ΔE at the third month from the start of use is It showed a self-cleaning property of 0-1.9. When no organic peroxide (dicumyl peroxide) was contained in the island component of the photocatalytic functional layer, 4 months were required until ΔE was in the range of 0 to 1.9. By using an organic peroxide in the island component of the photocatalytic functional layer, self-cleaning can be obtained at an early stage of one month, which is effective for maintaining aesthetics. Moreover, all the sheets of Examples 1 to 4 had high frequency weldability and were suitable for large tent structure construction.

[Comparative Example 1]
In Example 1, a sheet was obtained in the same manner as in Example 1 except that the combined use of the vinylidene fluoride resin mixture of Formulation 1 was omitted. The resulting sheet was exposed outdoors for 1 year and evaluated for antifouling properties. As a result, accumulation of dirt adhesion due to bleed of the plasticizer was severe, and ΔE was a rating of 4 in 7.6.

[Comparative Example 2]
In Example 1, a sheet was obtained in the same manner as in Example 1 except that the photocatalyst particles were omitted from the vinylidene fluoride resin mixture (containing photocatalyst particles) of Formulation 1. The obtained sheet was exposed outdoors for 1 year to evaluate the antifouling property. As a result, ΔE was 3.6, which was an evaluation 3 level.

[Comparative Example 3]
In Example 2, a sheet was obtained in the same manner as in Example 1 except that the combined use of the vinylidene fluoride resin mixture of Formulation 3 was omitted. The resulting sheet was exposed outdoors for 1 year and evaluated for antifouling properties. As a result, accumulation of dirt adhesion due to bleed of the plasticizer was severe, and ΔE was 4 levels of 9.9.

[Comparative Example 4]
In Example 2, a sheet was obtained in the same manner as in Example 2 except that the photocatalyst particles were omitted from the vinylidene fluoride resin mixture of Formulation 3 (containing photocatalyst particles). The obtained sheet was exposed outdoors for 1 year to evaluate the antifouling property. As a result, ΔE was 3.6, which was an evaluation 3 level.

  As a result of the outdoor exposure test for one year, the sheets of Comparative Examples 1 to 4 all exceeded ΔE = 2, and a sufficient self-cleaning antifouling effect was not obtained as an antifouling sheet.

  By using the self-cleaning antifouling sheet of the present invention for industrial materials such as medium and large tents, membrane structure building members such as tent warehouses, outdoor large signboards, store-integrated interior lighting signs, etc. While maintaining the photocatalyst layer while exhibiting the dirt removal effect due to the decomposition action, it can maintain the antifouling effect for a long time from the start of use of the membrane material, so the appearance of the above membrane structure buildings and signs It is possible to maintain beautifully without maintenance.

1: Flexible sheet 2: Sheet-like base material 2-1: Fiber fabric 2-2: Thermoplastic resin layer 2-3: Fiber composite laminate 3: Photocatalyst functional layer 3-1: Photocatalyst particle-free region 3- 2: Photocatalyst particle containing area 3-1-a: Island component: from synthetic resin (B) 3-2-b: Sea component: composed of synthetic resin (A) 4: Photocatalyst particles 5: Adhering to dirt (initial dirt)

Claims (3)

  A flexible sheet having a photocatalyst functional layer on one or more surfaces of a sheet-like substrate, wherein the photocatalyst functional layer forms a sea-island microstructure comprising a photocatalyst particle-containing region and a photocatalyst particle-free region. In the structure, the sea component is the photocatalyst particle-containing region formed from the synthetic resin (A) containing photocatalyst particles, and the island component is the photocatalyst particle non-containing formed by the synthetic resin (B) containing no photocatalyst particles A self-cleaning antifouling sheet, characterized in that the synthetic resin (A) is hardly decomposable due to photocatalytic activity, and the synthetic resin (B) is degradable with respect to photocatalytic activity.   The self-cleaning antifouling sheet according to claim 1, wherein the island component further contains 0.001 to 1% by mass of a peroxide with respect to the synthetic resin (B).   The self-cleaning antifouling sheet according to claim 1 or 2, wherein the sheet-like substrate is a fiber composite laminate comprising a fiber fabric as a core material.