JPH0978454A - Sheet product for outdoor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet product for outdoor uses, capable of self-washing the surface of the sheet product with rain water, etc., or drying the wet surface of the sheet product in a short time by disposing a hydrophilic surface layer containing photocatalyst particles on the outer surface of the sheet main body directly or through an intermediate layer for protecting the main body of the sheet. SOLUTION: A hydrophilic surface layer 2 such as a silicone resin later containing photocatalyst particles such as titanium dioxide particles is formed on the outer surface of a sheet main body 1 comprising a woven fabric or nonwoven fabric directly or through an intermediate layer comprising an aluminum vacuum deposition film or an aluminum particle-containing film for protecting the sheet main body 1 by an oxidation-reduction reaction due to the photocatalyst to obtain the sheet product for outdoor uses. Or a water-repelling film may be disposed on the back surface of the sheet or between the sheet main body 1 and the hydrophilic surface layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to outdoor seat products such as automobile cover sheets, tents, architectural cover sheets, and coats and umbrellas.

[0002]

2. Description of the Related Art As a matter of course, a sheet product used outdoors such as an automobile cover has dirt attached to its surface. It is considered that this stain is a mixture of combustion products such as carbon black, urban dust and inorganic dust such as clay minerals (Yoshinori Tachibana, "Test method for promoting contamination of exterior wall finishing materials" Japan Architectural Institute of Japan Structural Papers, 404, October 1989, P15-2
4).

[0003] Conventionally, no countermeasures have been taken for these products to attach dirt, or a water-repellent coating such as polytetrafluoroethylene is applied on the surface.

Recently, however, it has been considered preferable to make the surface of the coating film hydrophilic with respect to urban dust containing lipophilic components (Polymer, Vol. 44, May 1995, p.
307), and it has been proposed to coat buildings with hydrophilic graft polymers (Chemical Industry Daily, January 30, 1995).

Further, as hydrophilic coatings currently on the market, acrylic resins, acrylic silicone resins, aqueous silicones, block polymers of silicone resins and acrylic resins, acrylic styrene resins, sorbitan fatty acid ethylene oxide, sorbitan fatty acid esters, Examples include urethane-based acetates, cross-linked urethanes of polycarbonate diols and / or polyisocyanates, and polyacrylic acid alkyl ester cross-linked products.

[0006]

The water repellent coating is less effective against urban dust containing lipophilic components,
Contamination adheres over time and it is difficult to remove the adhered dirt.
Further, the contact angle of the hydrophilic graft polymer with water is 30.
４０40 °. On the other hand, the contact angle of inorganic dust such as clay mineral with water is 20 to 50 °. Therefore, the graft polymer cannot be said to be effective against inorganic dust.
Further, all of the commercially available hydrophilic paints such as acrylic resins have a contact angle with water of 50 to 70 ° and cannot prevent the stains due to the urban dust containing lipophilic components. Furthermore, all hydrophilic coatings have the drawback that their hydrophilicity deteriorates over time.

[0007]

According to the present invention, in order to prevent dirt from adhering to the surface of a sheet product or to easily remove the adhered dirt, the surface of the sheet product is hydrophilic rather than water-repellent. In light of the recently announced fact that it is more effective to give the above, in addition to the action of degrading dirt and the like by a redox reaction on the photocatalyst particles such as titanium oxide, the surface of the article is made hydrophilic ( The present invention has been made based on the fact that the present inventors uniquely found that it has a superhydrophilicizing effect.

Here, the decomposition action of the substance by the photocatalyst particles is based on an oxidation-reduction reaction, and when the photocatalyst particles are irradiated with ultraviolet rays or the like, electron-hole pairs are generated by photoexcitation, of which electrons generate surface oxygen. It is reduced to produce superoxide ions (O ₂ ⁻ ), and holes oxidize surface hydroxyl groups to produce hydroxyl radicals (· OH), and these extremely reactive active species (O ₂ ⁻ or The substance attached to the surface is decomposed by the redox reaction of (OH).

On the other hand, the hydrophilizing action of the photocatalyst particles newly discovered by the present inventors has not been completely clarified on its theoretical basis, but a hydroxyl group (O
H ^-) chemically adsorbed onto the surface of the photocatalyst particles, or a hydroxyl group (OH ^-) is replaced with an organic group, further the hydroxyl (OH ^-)
It is considered that water molecules in the air are physically adsorbed and the amount of physically adsorbed water is increased, whereby the hydrophilicity of the surface is increased and a superhydrophilic surface is realized.

As a specific example, the case where the surface layer is made of a silicone resin having a Si--O bond will be described. Before the photocatalyst particles are irradiated with light, as shown in FIG.
Since the alkyl group (R) is bonded to the atom, the surface layer shows hydrophobicity. However, when light having an energy higher than the band gap energy of the photocatalyst particles is irradiated, first, as shown in FIG. alkyl group (R) by the photocatalytic effects hydroxyl - is substituted (chemisorption), further the hydroxyl ^(OH) - exhibit hydrophilic water molecules in the air are physically adsorbed ^(OH).

Further, titanium oxide (Ti
O ₂ ) will be described. The state shown in FIG. 2A before the light irradiation is changed to the state shown in FIG. 2A when the light is irradiated, as shown in FIG. 2B. hydroxyl group constituting the (OH ^-) is a Ti atom, a hydrogen atom (H ⁺⁾ is chemically adsorbed to the oxygen atom (O), further the hydroxyl - water molecules and in the air a hydrogen atom (H ^{+) (OH)} Exerts hydrophilicity by physical adsorption.

[0012] In the above description, it is apparent that the decomposition and hydrophilization effect of a substance is completely different, if Shimese concrete examples, TiO ₂ anatase even TiO ₂ oxidation-reduction reaction However, rutile-type TiO ₂ shows almost no decomposition action of the substance based on the redox reaction. Also, among the photocatalysts, tin oxide does not show a decomposition effect of a substance based on a redox reaction. In these photocatalyst particles, the energy level of the conduction band is not sufficiently high, so that the reduction reaction does not proceed. As a result, the electrons excited by the photoexcitation in the conduction band become excessive, and the electron-hole pairs generated by the photoexcitation are oxidized and reduced. It is believed that they recombine without participating in the reaction. However, both rutile TiO ₂ and tin oxide exhibit a hydrophilizing action. Further, the photocatalytic layer needs to have a thickness of at least 100 nm in order to exhibit the decomposing action of the substance, but it is possible for the photocatalytic layer to exhibit a hydrophilizing action if it has a thickness of several nm or more. From these facts, it can be said that the decomposition action of the substance by the photocatalyst and the hydrophilization action are completely different.

The present invention has been made based on the above findings, and the sheet product used outdoors according to the present invention has a hydrophilic surface layer containing photocatalyst particles on the outer surface thereof. With this configuration, the surface of the product is self-cleaned with rainwater or the like.

When the sheet product is made of woven or non-woven fabric, a hydrophilic surface layer containing photocatalyst particles may be formed on the surface of the fibers constituting the woven or non-woven fabric.
By doing so, the step of imparting hydrophilicity later can be omitted, and the hydrophilic surface layer is less likely to peel off.

It is also possible to provide an intermediate layer made of, for example, a vapor-deposited aluminum film or a film containing aluminum particles between the sheet product body and the hydrophilic surface layer containing photocatalyst particles. By doing so, the sheet product main body can be protected from the redox reaction by the photocatalyst.

Further, a water-repellent film may be provided between the sheet product body and the hydrophilic surface layer containing photocatalyst particles, or on the back surface of the sheet product body. Water can easily enter by providing the hydrophilic surface layer, but this can be prevented by providing the water-repellent film.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 3A is a perspective view of an automobile cover sheet as an example of an outdoor sheet product according to the present invention, FIG. 3B is a perspective view of a tent as an example of an outdoor sheet product according to the present invention, and FIG. FIG. 3 is an enlarged cross-sectional view of a cover sheet for the vehicle or a sheet forming a tent,
A sheet product such as an automobile cover sheet has a hydrophilic surface layer 2 containing photocatalyst particles on an outer surface of a sheet body 1 made of a woven cloth.
Is formed.

As a method of forming the hydrophilic surface layer 2, since sheet products generally have poor heat resistance, photocatalyst particles are mixed with a resin which cures at a low temperature of about room temperature to form a coating, which is sprayed, A method of applying to the surface of the sheet product by a roll method or the like is preferable. Examples of the resin that cures at a temperature as low as room temperature include the following.

Methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltrit-butoxysilane, ethyltrichlorosilane, ethyltribromosilane, ethyltrimethoxysilane, ethyltrimethoxysilane. Ethoxysilane, ethyltriisopropoxysilane, ethyltri-t-butoxysilane, n-propyltrichlorosilane, n-propyltribromosilane, n-
Propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltriisopropoxysilane, n
-Propyltri-t-butoxysilane, n-hexyltrichlorosilane, n-hexyltribromosilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltriisopropoxysilane, n-
Hexyltri-t-butoxysilane, n-decyltrichlorosilane, n-decyltribromosilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, n
-Decyltriisopropoxysilane, n-decyltri-t
-Butoxysilane, n-octadecyltrichlorosilane, n-octadecyltribromosilane, n-octadecyltrimethoxysilane, n-octadecyltriethoxysilane, n-octadecyltriisopropoxysilane, n-octadecyltrit-butoxysilane, phenyltrichloro Silane, phenyltribromosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, phenyltri-t-butoxysilane, tetrachlorosilane, tetrabromosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane , Tetrabutoxysilane, dimethoxydiethoxysilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldimethoxysilane, dimethyldiethoxy Silane, diphenyl dichlorosilane, diphenyl bromine, diphenyldimethoxysilane, diphenyldiethoxysilane, phenylmethyl dichlorosilane, phenyl methyl dibromo silane,
Phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, triethoxyhydrosilane, tribromohydrosilane, trimethoxyhydrosilane, isopropoxyhydrosilane, tri-t-butoxyhydrosilane, vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane Silane, vinyltriisopropoxysilane, vinyltri-t-butoxysilane, trifluoropropyltrichlorosilane, trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane, tri Fluoropropyltri-t-butoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxy Cypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ
-Glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriisopropoxysilane, γ-glycidoxypropyltri-t-butoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldi Ethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriisopropoxysilane, γ-
Methacryloxypropyltri-t-butoxysilane, γ
-Aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropyltrit-butoxysilane , Γ-
Mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltriisopropoxysilane, γ-mercaptopropyltrit-
Butoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and their partial hydrolysates or mixtures thereof can be used. .

In order to secure good hardness and smoothness of the silicone resin film, it is preferable to contain 10 mol% or more of the three-dimensional crosslinked siloxane. In order to provide sufficient flexibility of the resin film while securing good hardness and smoothness, it is preferable to contain 60 mol% or less of the two-dimensional crosslinked siloxane. In order to increase the rate at which the organic group bonded to the silicon atom of the silicone molecule is replaced with a hydroxyl group by photoexcitation, use is made of a silicone in which the organic group bonded to the silicon atom of the silicone molecule is an n-propyl group or a phenyl group. Is preferred. An organopolysilazane compound having a silazane bond can be used instead of the silicone having a siloxane bond.

Titanium oxide is most preferable as the photocatalyst particles, but in addition to this, ZnO, SnO ₂ and SrTi are also used.
Examples thereof include metal oxides such as O ₃ , WO ₃ , Bi ₂ O ₃ and Fe ₂ O ₃ . It is considered that, since a metal element and oxygen are present on the surface, a hydroxyl group (OH ⁻ ) is easily adsorbed on the surface, and therefore, it is easy to exhibit hydrophilicity. Titanium oxide may be either anatase type or rutile type, but if the decomposition action of the substance is desired, the anatase type is selected, and if firing at low temperature or if firing is not performed, rutile type is selected.

FIG. 5 is a sectional view similar to that of FIG. 4 showing another embodiment. In this embodiment, an intermediate layer 3 is provided between the cover sheet body 1 and the hydrophilic surface layer 2. The intermediate layer 3 is for preventing the sheet product main body 1 from being decomposed or deteriorated by a redox reaction by a photocatalyst, and is specifically configured by an aluminum vapor deposition film or a film containing aluminum particles.

When the intermediate film 3 is formed of an aluminum vapor deposition film or the like, it also functions as a heat ray reflection film and is therefore effectively used as a cover sheet for automobiles, tents and the like.

It is also effective to form a water-repellent film instead of the intermediate film 3 or separately from the intermediate film 3. That is, by forming the hydrophilic surface layer 2, water is retained on the surface and water easily enters the inside. However, such a disadvantage can be prevented by forming a water repellent film. The water repellent film may be formed on the back side surface of the cover sheet body 1.

FIG. 6 is a cross-sectional view of a fiber showing another embodiment, and the hydrophilic surface layer 2 can be formed on the surface of the fiber 4 constituting the cover sheet body 1 as in this embodiment. With such a configuration, the peeling resistance of the hydrophilic surface layer 2 against rubbing can be enhanced.

(Examples and Comparative Examples) A surface layer was formed by coating a surface of a commercially available automobile cover sheet with a silicone resin containing titanium oxide sol in a proportion of 0 to 80%. Then, this surface layer was irradiated with ultraviolet rays of 0.5 mW / cm ² . The results are shown in (Table 1) below.

[0027]

[Table 1]

Further, each surface is wetted with water and the temperature is adjusted to 25
The results of naturally drying at 30 ° C. for 30 minutes are shown in (Table 2) below.

[0029]

[Table 2]

[0030]

As described above, according to the present invention, a hydrophilic surface layer containing photocatalyst particles is formed on the outer surface of sheet products such as automobile cover sheets, tents, and architectural cover sheets. The surface can be self-cleaned with rainwater. This hydrophilicity is maintained / recovered by irradiation with ultraviolet rays or the like, so that the product surface can be kept hydrophilic for a long period of time. Further, since the hydrophilic surface layer spreads water droplets thinly, the once wet surface can be dried in a short time.

When the photocatalyst particles are irradiated with ultraviolet rays or the like, they cause an oxidation-reduction reaction, so that the dirt components attached to the surface are decomposed. Therefore, it becomes difficult for the dirt component itself to adhere.

When a hydrophilic surface layer containing photocatalyst particles is formed on the surface of fibers constituting the sheet product, the hydrophilic surface layer is less likely to be peeled off by rubbing or the like,

Further, by providing an intermediate layer made of, for example, a vapor-deposited aluminum film or a film containing aluminum particles between the sheet product body and the hydrophilic surface layer containing photocatalyst particles, the sheet product body can be prevented from the redox reaction by the photocatalyst. Can be protected.

Further, by providing a water-repellent film between the sheet product main body and the hydrophilic surface layer containing photocatalyst particles, or on the back side of the sheet product main body, water generated by providing the hydrophilic surface layer is provided. It can cover the ease of intrusion.

[Brief description of drawings]

1A is a conceptual diagram of a hydrophobic surface, and FIG. 1B is a conceptual diagram of a hydrophilic surface.

FIG. 2 is a diagram illustrating a process of imparting hydrophilicity to a surface layer made of photocatalytic particles.

3A is a perspective view of an automobile cover sheet as an example of an outdoor sheet product according to the present invention, and FIG. 3B is a perspective view of a tent as an example of an outdoor sheet product according to the present invention.

FIG. 4 is an enlarged cross-sectional view of the cover sheet body.

5 is a sectional view similar to FIG. 4 showing another embodiment.

FIG. 6 is a cross-sectional view of fibers showing another embodiment.

[Explanation of symbols]

1 ... Cover sheet body, 2 ... Hydrophilic surface layer, 3 ... Intermediate layer, 4 ... Fiber.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location // B60J 11/00 D06M 11/00 C (72) Inventor Toshiya Watanabe 2-chome Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka No. 1-1 Totoki Co., Ltd. (72) Inventor Makoto Senkoku 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu City, Fukuoka Prefecture Totoki Kikai Co., Ltd.

Claims (5)

[Claims] 1. A sheet product used outdoors,
An outdoor sheet product, wherein a hydrophilic surface layer containing photocatalyst particles is formed on the outer surface of the sheet product. 2. The outdoor sheet product according to claim 1, wherein the sheet product is made of a woven or non-woven fabric, and a hydrophilic surface layer containing photocatalyst particles is formed on the surface of fibers constituting the woven or non-woven fabric. Outdoor seat products characterized by 3. The outdoor sheet product according to claim 1, wherein the sheet product body is protected from a redox reaction by a photocatalyst between the sheet product body and a hydrophilic surface layer containing photocatalyst particles. An outdoor sheet product characterized by having an intermediate layer that 4. The outdoor sheet product according to claim 3, wherein the intermediate layer is an aluminum vapor deposition film or a film containing aluminum particles. 5. The outdoor sheet product according to claim 1, wherein a water-repellent film is provided between the sheet product body and a hydrophilic surface layer containing photocatalyst particles, or on the back surface of the sheet product body. An outdoor seat product characterized by being provided with.