Stock material or miscellaneous articles – Circular sheet or circular blank – Recording medium or carrier
Reexamination Certificate
2001-06-08
2004-05-18
Zacharia, Ramsey (Department: 1773)
Stock material or miscellaneous articles
Circular sheet or circular blank
Recording medium or carrier
C428S220000, C428S411100, C428S500000, C428S522000, C427S256000, C427S385500, C525S105000, C525S106000
Reexamination Certificate
active
06737145
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel organic-inorganic composite graded material, a process for the production thereof and its use. More specifically, the present invention relates to an organic-inorganic composite graded material comprising a chemical bond product in which an organic polymer compound and a metallic compound are chemically bonded to each other, having a component-graded structure in which the content of the metallic compound continuously varies along the thickness direction of the material and being useful as a functional material in various fields, a process for efficiently producing the above material, a coating agent made of the above graded material for forming a coating, such as a coating film, an adhesive for bonding an organic material to an inorganic or metallic material or an intermediate film to be interposed between an organic substrate and an inorganic or metallic material layer, and base materials or articles for which the above graded material is applied.
TECHNICAL BACKGROUND
In recent years, with a diversification of demands to performances and functions of organic polymer materials, it is difficult to comply with such demands with a single polymer compound, and a different material having different properties is added to a polymer compound to form a composite compound.
For example, it is general practice to disperse a reinforcing material in an organic polymer material to modify the physical properties of the polymer material. Specifically, an organic or inorganic fibrous material such as a carbon fiber, a glass fiber, a metal fiber, a ceramic fiber, an aramid fiber, etc., or a powdery inorganic filler of calcium carbonate, silica, alumina, etc., is added and homogeneously dispersed.
Further, studies are actively made by mixing different polymer compounds, optionally, together with a compatibilizer to form a polymer alloy which exhibits novel functions.
A graded functional material recently attracts attention, which material is a composite material obtained by gradually changing the composition of the material so that the properties of its front and reverse completely differ from each other. For example, a metal-ceramic composite graded functional material having both the heat resistance of ceramic and the strength of metal has been developed as an airframe material of a supersonic aircraft.
Such graded functional materials are classified into an inorganic graded material, an organic graded material and an organic-inorganic composite graded material. These graded functional materials are prepared by mixing a plurality of materials such as a plurality of inorganic materials of different kinds, a plurality of organic materials of different kinds or a combination of at least one organic material and at least one inorganic material and controlling these materials such that their distribution density, orientation, etc., differ from place to place. The graded functional materials can exhibit properties of a plurality of component materials. It is therefore expected that the above materials can be applied to the filed of aerospace industries, the field of automobiles, the field of electronics, the medical field, the field of energy and, further, the filed of shields against radiations and electromagnetic waves.
Meanwhile, since there was found a so-called Honda-Fujishima effect that water is photodecomposed into hydrogen and oxygen when a semiconductor such as titanium dioxide is used as a photoelectrode (“Kogyo Kagaku Zasshi”, Vol. 72, pages 108 to 113 (1969)), studies have been vigorously made to develop photocatalysts and put them into practical use. For example, when semiconductor particles of titanium dioxide are excited with light having energy greater than their band gap, electrons are generated in a conduction band, and holes are generated in a valence band. The above photocatalysts utilize electron-hole pairs rich with energy.
Application of the above photocatalysts has been and is studied not only for deodorization, anti-fouling, an anti-microbial function and disinfection but also for decomposition and removal of various environmentally detrimental substances in drain or waste gas.
As photocatalysts, various compounds having semiconductive property are known. For example, there are known metal oxides such as titanium dioxide, iron oxide, tungsten oxide and zinc oxide and metal sulfides such as cadmium sulfide and zinc sulfide. Of these, titanium dioxide, particularly anatase type titanium dioxide, is useful as a practical photocatalyst. This titanium dioxide exhibits excellent photocatalysis when it absorbs light having a specific wavelength in an ultraviolet region included in usual light such as sunlight. Due to strong oxidation activity derived from the above photocatalysis, the titanium dioxide exhibits functions such as anti-fouling, deodorization, anti-microbial function, air-cleaning, water-cleaning and super-hydrophilicity.
Studies are being actively made at present to allow the photocatalyst such as titanium dioxide or the like to exhibit the above photocatalytic functions for their industrial utility. For example, when the photocatalyst is coated on a material surface or incorporated into a coating on a material surface in advance, it is possible to impart the material surface with the function of a decomposer of an organic substance only upon irradiation with light, and its practical use has begun for glass and tiles that are not easily soiled or a stool. Further, studies are being actively made for developing various functional articles utilizing the above photocatalyst. For example, studies are being made with regard to practical use of (1) construction materials capable of decomposing nitrogen oxide that constitutes a source of air pollution, with light energy of the sun, (2) glass having a surface coating made of a transparent photocatalyst, having capability of naturally decomposing an adhering soiling and having an anti-microbial effect, (3) a window film having a photocatalyst layer formed on its surface for utilizing the ultra-hydrophilic nature and an anti-fouling performance of the photocatalyst and being to be applied to a front surface side of a glass window and (4) a drain treating agent formed by coating silica gel particles with a fine titanium dioxide powder.
The photocatalysts having photocatalytic function such as titanium dioxide cannot be easily supported on an organic substrate such as a plastic substrate, and most of them require some binder. Further, when the photocatalyst is coated directly on an organic substrate or incorporated into such a substrate, there is caused a problem that the organic substrate inevitably deteriorates for a short period of time due to the photocatalysis.
For overcoming the above problem, attempts are made to form a coating film made of a photocatalyst such as titanium dioxide on the organic substrate through an organic adhesive. In this case, however, there is incurred an undesirable situation in which the adhesion between the binder and the photocatalyst decreases with the passage of time or opacification, an interference color, etc., are caused. Attempts are also made to form a coating film made of a photocatalyst such as titanium dioxide on the organic substrate through an inorganic adhesive. In this case, the adhesion to the substrate is not sufficient or the adhesive layer itself undergoes cracking, resulting in an undesirable situation in which the adhesion between the binder and the substrate decreases with the passage of time or opacification, an interference color, etc., are caused. Further, microcapsules formed by coating a photocatalyst such as titanium dioxide with silica have been developed, and attempts are made to incorporate the microcapsules into an organic substrate for imparting the organic substrate with deodorization and anti-microbial functions. In the above microcapsules, the photocatalyst is not easily exposed on a surface, so that the deterioration of the organic substrate is inhibited. Further, each capsule has a number of fine pores
Adachi Tatsuhiko
Fujishima Akira
Hashimoto Kazuhito
Nakayama Norihiro
Suzuki Taro
Nixon & Vanderhye P.C.
Ube Nitto Kasei Co., Ltd.
Zacharia Ramsey
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