Batteries: thermoelectric and photoelectric – Photoelectric – Cells
Reexamination Certificate
1999-04-27
2001-02-27
Chapman, Mark (Department: 1753)
Batteries: thermoelectric and photoelectric
Photoelectric
Cells
C427S074000, C427S214000, C502S101000, C502S527170
Reexamination Certificate
active
06194650
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a coated material which is excellent in terms of chemical and physical properties such as a catalytic activity and adsorptivity and also relates to a method for producing the same.
BACKGROUND OF THE INVENTION
As a method for obtaining a material which is excellent in terms of chemical and physical properties such as a catalytic activity and adsorptivity, a method in which a microporous substrate is coated with an organic or inorganic coating material and a method in which a coated material formed by a coating step is peeled off to obtain a microporous-surfaced material having on its surface an inverted configuration of the microporous configuration of the substrate is known.
In such a method, a coating material such as a sol or gel is coated on a surface of a substrate. However, this method involves a problematic closure of a micropore opening with the coating material when the substrate has a micropore whose diameter is less than a micron order(&mgr;m).
Accordingly, the coating material can not be penetrated into the innermost of the micropore, resulting in difficulty in obtaining an intended microporous-surfaced material effectively.
On the other hand, a method in which a coating material is coated onto a substrate by means of a gaseous phase method such as CVD is also proposed. However, in this method, a prolonged time period is required to allow the vapor of the coating material to be penetrated into the micropore. Especially in the case of a material having a low vapor pressure, only a small amount can be vaporized and the coating time is extremely prolonged.
In an attempt to overcome the problems mentioned above, a method in which a supercritical fluid containing a polymeric material dissolved therein is brought into contact with an inorganic porous membrane is proposed (Japanese Laid-Open Patent Publication No. 7-144121). Also a method is known in which a supercritical fluid containing a ceramic precursor such as a polycarbosilane or a polysilane dissolved therein is impregnated in a carbon/carbon complex where it is allowed to precipitate and then subjected to a heat treatment to form a ceramic membrane of SiC, SiN and the like on its surface thereby heightening its oxidation resistance (Japanese Laid-Open Patent Publication No. 1-308873).
Nevertheless, the methods disclosed in the publications described above involve, similarly as in the former two methods, the problematic closure of a micropore opening with the polymeric material when the micropore has a diameter less than a micron thereby preventing the supercritical fluid containing such a material from being penetrated sufficiently.
As a result, an intended coating can not be achieved.
An objective of the present invention is to overcome such conventional problems by providing a coated material and a method for producing the same, by which a coated material formed by coating the surface of a substrate efficiently with a reaction product can be obtained, and also by which a reaction product transferring or reproducing the microstructure of the substrate can be obtained after removing a part or all of the substrate from the coated material.
DISCLOSURE OF THE INVENTION
The first aspect of the present invention is a coated material comprising a substrate which has micropores, and a reaction product coated thereon along the surface configuration of the substrate and an inner wall of the micropores thereof.
The second aspect of the present invention is a coated material comprising a substrate having micropores a part of which is to be removed and, a reaction product coated along the surface configuration of the substrate and an inner wall of the micropores.
Any of these coated materials according to the present invention comprises a reaction product coated along the surface configuration of a microporous substrate into the innermost of the micropore. Accordingly, it exhibits an extremely excellent effect when applied to various uses as described hereinafter.
In addition, a substrate coated with the reaction product thus obtained or the reaction product itself can be imparted, depending on the properties of the reaction product, with a catalytic activity, a light catalytic activity, an adsorptivity, a heat resistance, a chemical resistance, an oxidation resistance, a conductivity, a ferromagnetism, a ferroelectricity, a superconductivity, a light function (reflex, absorption) and the like.
The reaction product may also be formed by mixing or laminating two or more components such as a chemically resistant membrane plus a photo-functional membrane.
The coated material may have the front side and the back side whose surfaces are both similar in their configurations to those of the micropores of the substrate or may have such a similar surface only on one side. In the latter case, the coated material may be used as a mold for reproducing the microporous configuration of the substrate.
A method for producing the excellent coated material described above is achieved by the following invention.
Thus, the third aspect of the present invention is a method for producing a coated material comprising a supercritical coating step wherein a reaction precursor is dissolved in a supercritical fluid to form a precursor fluid and then the precursor fluid is brought into contact with a substrate in the presence with a reaction initiator to allow a reaction between the reaction precursor and the reaction initiator, thereby coating a reaction product onto the substrate.
Also provided is a method for producing a coated material comprising:
a supercritical coating step wherein a reaction precursor is dissolved in a supercritical fluid to form a precursor fluid and then the precursor fluid is brought into contact with a substrate in the presence with a reaction initiator to allow a reaction between the reaction precursor and the reaction initiator, thereby coating a reaction product onto the substrate; and,
a removing step wherein at least a part of the substrate is removed.
The advantageous effects of the present invention are described below.
In the present invention, the reaction precursor is first dissolved in the supercritical fluid to prepare a precursor fluid. In order to allow the reaction described above in the presence of a reaction initiator, a substrate containing the reaction initiator may for example be prepared. Then, the substrate is brought into contact with the precursor fluid by, for example, immersing the substrate in the precursor fluid, thereby allowing the precursor fluid to be penetrated into the micropore of the substrate.
In this step, the precursor fluid is readily be penetrated into the micropore since it employs the supercritical fluid as a solvent therefor. Since the reaction precursor dissolved in the supercritical fluid has a low molecular weight and a small molecular size, it does not close the opening of the micropore unlike a substance having a high molecular weight, such as the polymeric materials and polycarbosilanes employed in the conventional method.
Then the reaction precursor in the precursor fluid thus penetrated into the micropore reacts with the reaction initiator. Subsequently, the reaction precursor is converted into an intended reaction product, which coats the substrate.
Accordingly, the present invention allows the reaction product to be coated onto the surface of the substrate efficiently.
The supercritical fluid is a substance having solubilizability equivalent to that of fluid and dispersibility and viscosity close to those of gas. Therefore, it allows a large amount of a reaction precursor to be transported into the micropore readily and rapidly. The solubilizability can be adjusted by selecting temperature, pressure and entrainers (additives) appropriately.
The supercritical fluid may, for example, be carbon dioxide, methane, ethane, propane, methanol, ethanol, acetone, ethylene, butane and the like. Also in order to adjust the solubility of the reaction precursor in the supercritical fluid, an entrainer such as methanol, ethanol, ac
Fukushima Yoshiaki
Goto Yasutomo
Hayashi Hiroaki
Higuchi Kazuo
Inagaki Shinji
Chapman Mark
Kabushiki Kaisha Toyota Chuo Kenkyusho
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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