Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1995-03-24
1997-08-12
Dean, Karen A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524862, 252511, 428368, 428375, 428391, 428392, 428447, 428367, C08K 300, H01B 106, B32B 904
Patent
active
056566905
DESCRIPTION:
BRIEF SUMMARY
The invention relates to organopolysiloxane compositions which crosslink to give electrically conductive elastomers and their preparation. The invention furthermore relates to the production of shaped articles by injection molding.
U.S. Pat. No. 4,279,783 discloses organopolysiloxane compositions which crosslink to give electrically conductive elastomers and are obtained by mixing an organopolysiloxane mass which crosslinks to give an electrically conductive elastomer and comprises carbon black with 0.3 to 5.0% by weight, based on the total weight of the organopolysiloxane composition, of carbon fibers which have an average length of 1 to 6 mm.
There was the object of providing organopolysiloxane compositions which crosslink to give electrically conductive elastomers and can be prepared without co-using solvents, are free from cleavage products, can be pumped and can be used to obtain shaped articles by injection molding, and with which elastomers which have a lower specific resistance than electrically conductive organopolysiloxane elastomers known to date are obtained. The object is achieved by the invention.
The invention relates to organopolysiloxane compositions which crosslink to give electrically conductive elastomers and comprise an organopolysiloxane mass which crosslinks by addition to give an electrically non-conductive elastomer and (a) 11 to 30% by weight, based on the total weight of the organopolysiloxane composition, of carbon fibers having an average length of 0.1 to 10 mm.
The organopolysiloxane compositions according to the invention preferably have an average viscosity of 0.5.times.10.sup.6 to 5.times.10.sup.6 mPa.s at 25.degree. C., preferably 1.times.10.sup.6 to 3.times.10.sup.6 mPa.s at 25.degree. C.
The carbon fibers (a) used in the organopolysiloxane compositions according to the invention preferably have a length of 0.5 to 3 mm and a diameter of preferably 5 to 10 .mu.m, preferably 6 to 8 .mu.m, and are commercially obtainable. Carbon fibers are also to be understood as meaning graphite fibers.
All the organopolysiloxane masses known to date which crosslink by addition to give electrically non-conductive elastomers can be used as the organopolysiloxane masses which crosslink by addition to give electrically non-conductive elastomers. The organopolysiloxane masses which crosslink by addition to give electrically non-conductive elastomers preferably comprise, as essential constituents, aliphatic carbon-carbon multiple bonds,
Preferred organopolysiloxanes (b) are those of the general formula R.sub.3-a R.sub.a.sup.1, radicals which are free from aliphatic carbon-carbon multiple bonds and can optionally be halogenated, multiple bonds, viscosity of these organopolysiloxanes is 100 to 10.sub.6 mPa.s, preferably 200 to 200,000 mPa.s, at 25.degree. C.,
The radicals are R preferably contain 1 to 18 carbon atoms per radical. Examples of radicals R are alkyl radicals, such as the methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, n-pentyl, iso-pentyl, neo-pentyl and tert.-pentyl radicals; hexyl radicals, such as the n-hexyl radical; heptyl radicals, such as the n-heptyl radical; octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2,2,4-trimethylpentyl radical; nonyl radicals such as the n-nonyl radical; decyl radicals, such as the n-decyl radical; dodecyl radicals, such as the n-dodecyl radical; octadecyl radicals, such as the n-octadecyl radical; cycloalkyl radicals, such as cyclopentyl, cyclohexyl and cycloheptyl radicals and methylcyclohexyl radicals; aryl radicals, such as the phenyl, naphthyl, anthryl and phenanthryl radicals; alkaryl radicals, such as o-, m- and p-tolyl radicals, xylyl radicals and ethylphenyl radicals; and aralkyl radicals, such as the benzyl radical and the .alpha.- and .beta.-phenylethyl radical.
Examples of halogenated hydrocarbon radicals R are haloalkyl radicals such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2',2',2'-hexafluoroisopropyl radical and the heptafluoroisopropyl radical, and haloaryl radicals, such
REFERENCES:
patent: 2476166 (1949-07-01), Wayo
patent: 3445420 (1969-05-01), Kookootsedes
patent: 4279783 (1981-07-01), Kehrer et al.
patent: 4303735 (1981-12-01), Kehrer et al.
AN 84-172493/28, the English Derwent abstract.
AN 81-64801D, the English Derwent abstract.
Birneder Richard
Fink Peter
Noemmer Katharina
Pradl Ferdinand
Connaughton Martin
Dean Karen A.
Wacker-Chemie GmbH
LandOfFree
Organopolysiloxane compositions which crosslink to give electric does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Organopolysiloxane compositions which crosslink to give electric, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Organopolysiloxane compositions which crosslink to give electric will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-161189