Coating processes – With post-treatment of coating or coating material – Chemical agent applied to treat coating
Reexamination Certificate
2000-01-11
2001-12-25
Beck, Shrive P. (Department: 1762)
Coating processes
With post-treatment of coating or coating material
Chemical agent applied to treat coating
C427S290000, C427S292000, C427S340000, C427S355000, C427S377000
Reexamination Certificate
active
06333074
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a water repellent coating film, a method and an apparatus for manufacturing the same, and a water repellent coating material composition, and more particularly to a water repellent coating film that comprises a microcrystalline polymer having at least a fluorocarbon group and has a rough surface.
BACKGROUND OF THE INVENTION
Conventionally, a method for coating a surface with a hydrophilic resin is used for the fin of the heat exchanger of an air conditioner, etc. in order to more readily eliminate dew condensation water during operation. However, with traditional methods for making a surface hydrophilic, dew condenses and freezes, i.e., frost forms, particularly during winter in cold environments. This frozen water is difficult to eliminate and reduces operating efficiency. In fact, air conditioning operation must be occasionally stopped to melt and remove the frost which builds up.
Thus, both an extra heater, and energy it uses, is required for removing frost. Also, such a process is not desired as air conditioning operation must be occasionally stopped.
SUMMARY OF THE INVENTION
In order to solve conventional problems, the present invention seeks to provide a coating film that has a high contact angle to a water drop and excellent water repellency as well as a method for manufacturing the same. Further, the present invention aims to provide a water repellent coating film that facilitates removal of the dew which condenses on an air conditioner to prevent the fin of the heat exchanger from freezing and allow continuous operation of air conditioning.
In one aspect, a first coating film of the present invention comprises a polymer having a fluorocarbon group formed on a surface of a substrate, wherein the film comprises a microcrystalline polymer and has a rough surface, and a part of molecules forming the film are covalently bonded to the surface of the substrate. Such a structure can provide a coating film that has a high contact angle to a water drop and excellent water repellency. Also, the structure can improve the water separation of the surface of the base material.
In the above structure, it is preferable that the microcrystalline polymer having a fluorocarbon group is crosslinked by at least a siloxane (—SiO—) bond or a titanium-oxygen (—TiO—) bond. This example can provide excellent durability and improve the water separation of the surface of the base material.
A second coating film of the present invention comprises a fine particle or a whisker as a core and a microcrystalline polymer having a fluorocarbon group that is formed to “wrap” the fine particle or the whisker, and has a rough surface. Such a structure can provide a coating film that has a high contact angle to a water drop and has excellent water repellency. Also, the structure can improve the water separation of the surface of the base material.
In the above structure, it is preferable that the microcrystalline polymer having a fluorocarbon group is crosslinked by at least a siloxane (—SiO—) bond or a titanium-oxygen (—TiO—) bond. This example can provide excellent durability and improve the water separation of the surface of the base material.
In the above structure, it is further preferable that the microcrystalline polymer having a fluorocarbon group that is crosslinked by a siloxane bond or a titanium-oxygen bond is formed by a hydrolysis reaction. This can provide a less impurity content and excellent durability and improve the water separation of the surface of the base material.
In the above structure, it is still further preferable that the roughness of the surface is in the range of 0.1 to 100 &mgr;m. This can provide a less impurity content, excellent durability, and super-water-repellency, and improve the water separation of the surface of the base material.
In the above structure, it is preferable that the roughness of the film is in the range of 0.1 to 100 &mgr;m. This can provide excellent durability and super-water-repellency and improve the water separation of the surface of the base material.
In the above structure, it is preferable that the film is cloudy with a color of white or is opaque. This can provide high crystal strength, excellent durability, and super-water-repellency, and improve the water separation of the surface of the base material.
A water repellent heat exchanger fin according to the present invention comprises a water repellent coating film that has a fluorocarbon group and a rough surface and is formed on a surface of a base material. This structure can effectively remove the dew that condenses on an air conditioner to prevent the fin of the heat exchanger from freezing and allow continuous operation of air conditioning.
In the above structure, it is preferable that the water repellent coating film is formed on a surface of a base material which, during processing, is provided with a rough surface. In other words, by forming the film that comprises a microcrystalline polymer having a fluorocarbon group and has a rough surface on the surface of the base material, the water separation of the surface of the base material of the water repellent heat exchanger fin can be improved.
In the above fin, it is preferable that the roughness of the surface of the base material is in the range of 0.1 to 50 &mgr;m. This structure is unlikely to cause the peeling of the coating film. The structure can provide excellent durability and super-water-repellency and improve the water separation of the surface of the base material.
An air conditioner according to the present invention uses a fin with a water repellent coating film formed in the heat exchange part. This structure can provide an energy-saving air conditioner that has very high water repellent efficiency and provides excellent amenity. In other words, this structure can easily remove the dew that condenses on an air conditioner even in cold environments to prevent the fin of the heat exchanger from freezing and allow continuous operation of air conditioning.
A water repellent coating material composition of the present invention comprises at least a material that has a hydrolyzable group having Si or Ti and a fluorocarbon group, a fine particle or a whisker, and a nonaqueous organic solvent. This coating material can provide a water repellent coating film with a very high manufacturing efficiency.
In the above water repellent coating material composition, it is preferable that the nonaqueous organic solvent is at least one solvent selected from the group consisting of xylene, toluene, normal paraffin, and silicone. The use of such a solvent allows efficiently growing a microcrystal in manufacturing a water repellent coating film.
In the above water repellent coating material composition, it is preferable that, as the material that has a hydrolyzable group having Si or Ti and a fluorocarbon group, a material that is expressed by CF
3
—(CF
2
)
n
—(R)
m
—SiX
p
Cl
3−p
is used as a main component, in which n represents 0 or an integer, R represents an alkylene group, a vinylene group, an ethynylene group, an arylene group such as phenylene group, silicon, or a substituent having an oxygen atom, m represents 0 or 1, X represents H, an alkyl group, an alkoxy group, an isocyanate group, a fluorine-containing alkyl group, or a fluorine-containing alkoxy group, and p represents 0, 1, 2 or 3. By using such a material, the water repellency and durability of the coating film can be further improved.
In the above composition, it is preferable that the amount of the material that has a hydrolyzable group having at least one element selected from the group consisting of Si and Ti and a fluorocarbon group is 1 to 50% by weight, the amount of at least one filler selected from the group consisting of a fine particle and a whisker is 1 to 30% by weight, and the amount of the nonaqueous organic solvent is 20 to 98% by weight based on the total weight of the composition.
A method for manufacturing a first water repellent coating film of the present invention comprises coating a surface o
Mino Norihisa
Ogawa Kazufumi
Takebe Yasuo
Beck Shrive P.
Crockford Kirsten A.
Matsushita Electric - Industrial Co., Ltd.
Morrison & Foerster / LLP
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