Compositions – Electrically conductive or emissive compositions – Elemental carbon containing
Patent
1998-04-23
1999-06-01
Kopec, Mark
Compositions
Electrically conductive or emissive compositions
Elemental carbon containing
252507, 252508, 428922, 428924, H01B 118, H01B 124, B32B 502, B32B 2720
Patent
active
059085851
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an electrically conductive transparent film, a coating composition for forming such a film, and an antistatic layer made of the transparent film. The conductive transparent film can be used as substrates of display devices such as LC or EL display devices, as transparent electrodes, and for shielding electromagnetic waves in electronic equipment. The film is also useful for providing various transparent structures with antistatic properties while keeping transparency of the structures. Examples of such transparent structures include, e.g., cathode ray tubes or TV's or the like, glass or transparent plastic panels for dust-proof interior or exterior partitions or show windows, recording materials such as photographic films or optical or magnetic recording devices, and packages for semiconductor chips and electronic elements.
BACKGROUND ART
An electrically conductive transparent film has conventionally been formed on an electrical insulating substrate either the following process (1) or (2): to form a conductive transparent film of a metal oxide type, e.g., antimony-tin mixed oxide or tin-indium mixed oxide on a substrate; electrically conductive powder, e.g., one of the above-described mixed oxides, and a binder.
The dry process (1) produces a film having both good transparency and good conductivity. However, it requires a complicated apparatus having a vacuum system and has poor productivity. Another problem of the dry process is that it is difficult to apply to a continuous or big substrate such as photographic films or show windows.
On the other hand, the wet process (2) is advantageous in that it requires a relatively simple apparatus, has high productivity, and is easy to apply to a continuous or big substrate.
The conductive powder used in the wet process is a very fine powder having an average primary particle diameter of 0.5 .mu.m or less so as not to interfere with the transparency of the resulting film. However, such a fine powder is strong in binding power between particles and tends to re-agglomerate in a coating composition, thereby causing the coating composition to have a low stability.
Furthermore, since electric conductivity results from direct contact between powder particles, it is necessary for the conductive powder to be present in a dry film in a large proportion on the order of more than 50% by weight in order to provide the film with adequate electric conductivity. This increases the costs of a conductive film made by the wet process and leads to losses of physical (mechanical and thermal) properties of the film.
Carbon fibers, particularly graphitized carbon fibers have good electric conductivity and it has been attempted to use carbon fibers as a conductive material. In particular, those carbon fibers prepared by the vapor-phase growth (pyrolysis) method and optionally subjected to graphitization by heat treatment are attractive since they are hollow or solid thin fibers having an outer diameter of 0.1-10 .mu.m and having high electric conductivity.
Recently, carbon fibers much thinner than the above-described fibers by the conventional vapor-phase growth method have been developed. See, Japanese Patent Kokoku Publications Nos. 3-64606 and 3-77288; Japanese Patent Kokai Applications Nos. 1-131251, 3-174018, and 5-125619; and U.S. Pat. Nos. 4,663,230; 5,165,909; and 5,171,560. Such very thin carbon fibers (hereinafter referred to as carbon microfibers) are hollow fibers having a hollow core and their outer diameter is in the range of several to several ten nanometers (nm). Due to the diameter on the order of nanometers, carbon microfibers are also called nanotubes or carbon fibrils. It has been proposed to use such fibers as a reinforcing material in the manufacture of composite materials, or to utilize their electrical conductivity and employ them in antistatic materials, electrodes, and shields against electromagnetic waves.
U.S. Pat. No. 5,098,771 describes an electrically conductive coating and ink containing hollow carbon mic
REFERENCES:
patent: 4663230 (1987-05-01), Tennent
patent: 5098771 (1992-03-01), Friend
patent: 5165909 (1992-11-01), Tennent et al.
patent: 5171560 (1992-12-01), Tennent
patent: 5504133 (1996-04-01), Murouchi et al.
patent: 5549849 (1996-08-01), Namura et al.
patent: 5585037 (1996-12-01), Linton
Hyperion Catalysis International Inc.
Kopec Mark
Mitsubishi Materials Corporation
Mruk Brian
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