Toto Ltd.

Keiichiro Norimoto

Makoto Hayakawa

Toshiya Watanabe

Eiichi Kojima

Atsushi Kitamura

Mitsuyoshi Machida

Makoto Chikuni

Tamon Kimura

Yoshimitsu Saeki

Tatsuhiko Kuga

Yasushi Nakashima

Akira Fujishima

Kazuhito Hashimoto

Mitsuyoshi Kanno

A method of preventing or reducing fogging of a surface of a composite when subjected to humid conditions includes providing a composite with a surface. The composite includes a substrate and a photocatalytic surface layer. The photocatalytic surface layer includes a photocatalyst. The method further includes subjecting the photocatalyst to photoexcitation to render the surface of the composite hydrophilic, wherein, after the photoexcitation, the surface of the composite has a water wettability of less than 10&#xb0; in terms of the contact angle with water. The method further includes subjecting the composite to humidity that is sufficient to induce fogging of the substrate if the photocatalytic surface layer were absent.

Method for photocatalytically rendering a surface of a substrate superhydrophilic, a substrate with superhydrophilic photocatalytic surface, and method of making thereof

The surface of a substrate is coated with an abrasion-resistant photocatalytic coating comprised of a semiconductor photocatalyst. upon irradiation by a light having a wavelength of an energy higher than the bandgap energy of the photocatalyst, water is chemisorbed onto the surface in the form of hydroxyl groups (OH ) whereby the surface of the photocatalytic coating is rendered highly hydrophilic. In certain embodiments, the surface of a mirror, lens, or windowpane is coated with the photocatalytic coating to exhibit a high degree of antifogging function. In another embodiment, an article or product coated with the photocatalytic coating is disposed outdoors and the highly hydrophilic surface thereof is self-cleaned as it is subjected to rainfall. In a still another embodiment, an article is coated with the photocatalytic coating and, when the article is soaked in, rinsed by or wetted with water, fatty dirt and contaminants are readily released without resort to a detergent.

Method for photocatalytically rendering a surface of a substrate superhydrophilic, a substrate with a superhydrophilic photocatalytic surface, and method of making thereof

Multi-functional materials which have a photocatalytic layer with a photocatalytic function disposed on the surface of a base through a binder layer,interposed therebetween. Photocatalytic particles of the photocatalytic layer are joined together by a surface energy or solid-state sintering. The photocatalytic layer may have a structure in which fine particles fill interstices defined between photocatalytic particles or a structure in which no fine particles fill interstices defined between photocatalytic particles. A metal such as Ag, Pt, or the like may be fixed or not fixed to surfaces of the photocatalytic particles.

Multi-functional material with photocatalytic functions and method of manufacturing same

Multi-functional materials are classified into those which have a photocatalytic layer with a photocatalytic function directly disposed on the surface of a base and those which have a photocatalytic layer with a photocatalytic function disposed on the surface of a base through a binder layer interposed therebetween. Photocatalytic particles of the photocatalytic layer are joined together by a surface energy or solid-state sintering. The photocatalytic layer has a structure in which fine particles fill interstices defined between photocatalytic particles. A metal such as Ag, Pt, or the like may be fixed or not fixed to surfaces of the photocatalytic particles.

Multi-functional materials which have a photocatalytic layer with a photocatalytic function disposed on the surface of a base through an amorphous binder layer,interposed therebetween. Photocatalytic particles of the photocatalytic layer are joined together by a surface energy or solid-state sintering. The photocatalytic layer may have a structure in which fine particles fill interstices defined between photocatalytic particles or a structure in which no fine particles fill interstices defined between photocatalytic particles. A metal such as Ag, Pt, or the like may be fixed or not fixed to surfaces of the photocatalytic particles. A lower layer of the photocatalytic layer is embedded in the binder layer such that an intermediate layer is formed between the binder layer and the photocatalytic layer, the intermediate layer including components of the binder and photocatalytic layers in varying concentrations therethrough.

A method for hydrophilifying the surface of a substrate by taking advantage of photocatalytic action. The substrate has a photocatalytic titania coating (10). The surface of the photocatalytic coating (10) bears the solid acid that increases a hydrogen bond component (.gamma..sub.S.sup.h) in the surface energy in the solid/gas interface of the coating. Photoexcitation of the photocatalyst enhances the hydrogen bond component (.gamma..sub.S.sup.h) in the surface energy of the photocatalytic coating (10), accelerating the physical adsorption of molecules of water in the atmosphere through a hydrogen bond (16) onto hydrogen atoms in a terminal OH group (12), bonded to a titanium atom, and a bridge OH group (14) on the surface of the coating. This results in the formation of a high density, physically adsorbed water layer (18) on the surface of the photocatalytic coating (10), thus permitting the surface of the substrate to be easily hydrophilified. The method is applicable to antifogging, antifouling, selfcleaning and cleaning of articles.

Method for photocatalytically hydrophilifying surface and composite

Multi-functional materials which have a photocatalytic layer with a photocatalytic function disposed on the surface of a base through a binder layer 6 interposed therebetween. Photocatalytic particles of the photocatalytic layer are joined together by a surface energy or solid-state sintering. The photocatalytic layer may have a structure in which fine particles fill interstices defined between photocatalytic particles or a structure in which no fine particles fill interstices defined between photocatalytic particles. A metal such as Ag, Pt, or the like may be fixed or not fixed to surfaces of the photocatalytic particles.

Multi-functional material with photocatalytic functions and method of

The surface of a substrate is coated with an abrasion-resistant photocatalytic coating comprised of a semiconductor photocatalyst. Upon irradiation by a light having a wavelength of an energy higher than the bandgap energy of the photocatalyst, water is chemisorbed onto the surface in the form of hydroxyl groups (OH.sup.--) whereby the surface of the photocatalytic coating is rendered highly hydrophilic. In certain embodiments, the surface of a mirror, lens, or windowpane is coated with the photocatalytic coating to exhibit a high degree of antifogging function. In another embodiment, an article or product coated with the photocatalytic coating is disposed outdoors and the highly hydrophilic surface thereof is self-cleaned as it is subjected to rainfall. In a still another embodiment, an article is coated with the photocatalytic coating and, when the article is soaked in, rinsed by or wetted with water, fatty dirt and contaminants are readily released without resort to a detergent.

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Fukuoka, Japan

Keiichiro Norimoto