Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-08-31
2003-12-16
Harlan, Robert (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S266000, C252S500000, C428S407000, C523S201000, C523S206000
Reexamination Certificate
active
06664355
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for synthesizing conductive polymers by gas-phase polymerization and product thereof, and more particularly, to a process for synthesizing conductive polymers, which includes the steps of coating oxidant on a substrate surface in the unit of several microns and drying in a dryer, contacting monomers of a gas state to the coated substrate to cause a polymerization to the surface of the substrate, and cleaning the substrate for removing the non-reacted monomers and the oxidant after the polymerization, and to a product manufactured by the process.
2. Background of the Related Art
For several years, heterocyclic conductive polymers, which are in the form of a film, have been applied to electronic parts and various sensors. Polypyrrole and polythiophene of heterocyclo-compounds are easily synthesized and applied in various manners because they have high conductivity and excellent thermal stability. As the synthesis method, an electro-chemical polymerization and a chemical oxidative polymerization are well known. However, as the polymers synthesized by the above methods are not melted or dissolved like other conjugate conductive polymers, it is difficult that the polymers are processed to the film type. Moreover, the polymers synthesized by the chemical oxidative polymerization is formed in a particle type, and the polymers synthesized by the electrochemical polymerization is formed in a thin film type, and thereby they are low in mechanical strength and restricted in real applications.
To solve the above problems, there have been various approaches. As a general method, a method for mixing conductive polymers of a particle type with general polymers and composite materials to increase the processability and physical property has been disclosed. Especially, the electrochemical polymerization is widely known as a method for manufacturing a thin conductive composite film, but it has a difficulty in processability and a continuous process. Recently, a gas phase polymerization method has been disclosed. The gas phase polymerization method can be used to make a polymer film, on which oxidant is dispersed as a host material and contacted with the vapor of monomers to the host material. However, in this case, it takes long reaction time, and there are several problems.
Recently, it has been reported that a conductive film could be used for various purposes, i.e., for semiconductor IC chips, shipping trays or carrier tapes of precise electronic machines, and for displaying materials. Particularly, in the conductive film, a function as electromagnetic wave shielding material is brought out. However, the conductive film is manufactured by a method that the conductive polymers in themselves are polymerized, and then, filmed by an additional coating process. Furthermore, a metal thin film is used as a transparent conductive material by a vacuum evaporation method. They can have an excellent performance as electrode material. However, it is difficult to use because the material requires an additional process, like a vacuum molding, and manufacturing cost is too high.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a process for synthesizing conductive polymers by gas polymerization capable of reducing a manufacturing cost and reducing a manufacturing process in comparison with conventional methods, and capable of having an excellent thin film property and freely adjusting electric conductivity.
It is another object of the present invention to provide conductive polymers manufactured by the above synthesizing process.
It is a further object of the present invention to provide a method for using the manufactured conductive polymers to electric parts, EMI shielding and to a display.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A method for synthesizing conductive polymers according to the present invention includes the steps of: coating oxidant on a substrate surface in the unit of several microns and drying in a dryer, contacting monomers of a gas phase with the coated substrate to cause a polymerization, and cleaning the substrate for removing non-reacted monomer and oxidant after finishing the polymerization step.
The substrate is plastic or metal. The plastic material is selected from a group consisting of polyester, polycarbonates (PC), polyamide (PI), polyester sulfone (PES), and amorphous polyester (A-PET or PET-G).
The oxidant is selected from a group consisting of CuCl
3
, FeCl
3
, Iron(III) p-toluenesulfonate, and Cu((ClO
4
)
2
.6H
2
O (copper(II) perchlorate-hexahydrate). The oxidant is manufactured by dissolving in a single or mixed organic solvent selected from a group consisting of methyl alcohol, 2-butyl alcohol, ethyl cellosolve, ethyl alcohol, cyclohexane, acetone, ethyl acetate, toluene, and methyl ethyl ketone. It is possible to use a single solvent or mixed solvent, in which two to four kinds of solvents, are mixed. For example, the organic solvent, in which methyl alcohol, 2-butyl alcohol and ethyl cellosolve are mixed in a ratio of 7:2:1, 6:2:2 or 5:3:2, is used. The oxidant is manufactured in weight of 0.5~10% to total weight.
The substrate, on which the oxidant is coated, is dried in a drier of 50~80° C. for 0.1~8 minutes. Host polymers besides the oxidant may be added. The host polymers are selected from a group consisting of polybutyl acrylate, polycarbonates, polyester, polyurethane, polyvinyl chloride, polyvinyl alcohol, methyl cellulose, and chitosan. The host polymers are manufactured in weight of 0.5~5% to the total weight.
The monomers are selected from a group consisting of pyrrole, thiophene, furan, selenophene, 2,3-dihydrothio-3,4-dioxin, and their derivatives.
The monomers are vaporized in a vaporizing chamber and contacted on the substrate, on which the oxidant is coated, thereby causing polymerization. The polymerization temperature is 0~100° C. and the polymerization period of time is 10 seconds~40 minutes.
Non-reacted monomers and the oxidant after the polymerization are cleaned with methanol or water.
A series of the steps may be performed in stages and in succession.
The conductive polymers manufactured by the polymerization according to the present invention have the following chemical structure.
wherein, X is selected from a group consisting of sulfur (S), oxygen (O), selenium (Se) and NH; and R1 and R2 are selected from a group consisting of hydrogen, alkyl group including 3~15 carbons, ether including 3~15 carbons, halogen element and benzene group.
Preferably, the conductive polymers are polypyrrole, polythiophene, polyfuran, polyselenophene and their derivatives, and manufactured in the form of a film of thickness of 0.05~5 microns.
The conductive polymers manufactured according to the present invention may be used for preventing static electricity and electrostatic charge, for shielding electromagnetic wave, and for manufacturing a non-reflecting film having a structure of two or more layers including the polymers. Moreover, the conductive polymers may be used as a functional film of a flat type display or as a transparent electrode layer.
In the present invention, the oxidant is coated thin on the polymers or the metal substrate in the A unit of several tens hundreds, and contacted to the substrate, on which the oxidant is coated, while the monomers of the conductive polymers are made into a vapor of a gas state, so as to cause a direct polymerization, and thereby a conductive coated with thin film can be obtained.
However, in a conventional method, the conductive polymers are prepared by blended with host polymers and coated on the surface of the plastic or metal substrate. The conventional method usually has five or six steps from the synthesis to a final step for obtaining a film. Particularly, in consideration of a manufacturing cost for synthesizing the conductive polymer materials, the conductive polymer manufacturing method according to the present invention can save over two third of the manufacturin
Kim Eung Ryul
Kim Jin Yeol
Hanyang Hak Won Co. Ltd.
Harlan Robert
Jacobson & Holman PLLC
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