Compositions – Electrically conductive or emissive compositions
Patent
1993-04-08
1995-07-11
Lieberman, Paul
Compositions
Electrically conductive or emissive compositions
252512, 252514, 252518, 811556, 811565, 8532, 8624, 4271261, 4274191, H01B 100, H01B 108, H01B 102, D06P 382
Patent
active
054318564
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
This invention relates to conductive materials and has particular reference to imparting conductivity in materials such as natural or synthetic polymers for a variety of commercial, industrial uses. Such materials are used in many industrial processes in which a degree of conductivity is both necessary and desirable. For example in the paper making industry, the high speeds of modern paper making machines, particularly in the drying sections, can result in considerable induced electrostatic build up. There is a need, therefore, to provide fibre and layer components having a degree of conductivity which enable dissipation of the charge so generated.
In a similiar manner, in plastic fuel lines where there is a fast flow of fuel, for example, as in aircraft, the build-up of static in such lines can result in static discharge to earth and the formation of pin-holes in the fuel line with a consequence of leakage therefrom. Hitherto, fuel lines have been rendered conductive by forming in a surface of the fuel line a longitudinal strip of carbon filled polytetrafluoroethylene which provides a conductive path. While reasonably successful, the joint between such a filled conductive strip and the remainder of the substrate layer constituting the fuel line is a line of weakness. The continued passage of fuel at high speed through the line can result in rupture and/or erosion of the conductive strip, particularly at a bend, with a result that a discontinuity forms with attendant charge build up in the area of the discontinuity followed by pin-holing and subsequent leakage.
There is, therefore, a need in industry to provide polymeric structures which have a uniformity of conductivity and conductive properties.
Numerous methods for imparting electrical conductivity to polymeric substrates in general, and to synthetic polymeric fibres in particular, are known in the art. For example, one method for imparting electrical conductivity to polymeric fibres involves plating the surface of a fibre. This method requires etching of the surface of the fibre prior to plating in order to obtain satisfactory adhesion. The process involves sensitizing and activating the fibre prior to plating; as a result the properties of such electrically conducting fibre differ greatly from those of the starting fibre in, inter alia, softness, flexibility and smoothness.
In another prior art process, metal particles are kneaded into a polymer which is then spun into a yarn. This process suffers from the disadvantage that the metal particles tend to clog the nozzle during spinning. In addition, unless the metal content of the fibres is kept relatively low the electrically conducting fibre obtained by this method has inferior mechanical properties compared with the fibres of the same material not containing metal particles.
In a further process of the prior art, metal powder has been deposited in pores of a polymeric fibre; this requires an extraordinarily porous fibre and intricate process steps.
In U.S. Pat. Nos. 3,014,818 and 4,122,143, electrically conductive products are produced by reducing a copper compound to metallic copper. In U.S. Pat. No. 3,014,818 an electrically conductive fibrous material is produced by soaking the fibres such as cotton or acrylic fibres in a bath comprising a reducible salt of nickel, copper, cobalt or iron and the fibre is then subjected to a reducing treatment to obtain free metal particles which are dispersed through the interior of the fibre. Sodium borohydride and hydroxylamine are disclosed as satisfactory reducing agents. U.S. Pat. No. 4,122,143 discloses the use of cured products which may be obtained by reducing copper simultaneously with the curing of a resin. The disadvantage of this process is that it is not possible to use it to impart electrical conductivity to an existing fibre.
In each of the above referred to specific processes, the electrical conductivity is obtained by the presence of metallic copper in the polymeric material. Many polymeric materials have a strong affinity for monovale
REFERENCES:
patent: 3014818 (1961-12-01), Campbell
patent: 4122143 (1978-10-01), Momotari et al.
patent: 4336028 (1982-06-01), Tomibe et al.
patent: 4364739 (1982-12-01), Tomibe et al.
patent: 4378226 (1983-03-01), Tomibe et al.
patent: 4744860 (1988-05-01), Cop et al.
patent: 4876032 (1989-10-01), Liepins et al.
patent: 5154727 (1992-10-01), Dyer
Bajda Piotr J.
Kobus Jerzy Z.
Koprowska Joanna
Okoniewski Marian K.
Ratajczyk Barbara E.
Instytut Wlokiennictwa
Kopec M.
Lieberman Paul
LandOfFree
Conductive fibres does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Conductive fibres, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conductive fibres will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-501532