Patent GB-769823-A (GB)
Title: Improvements in rubber treatment
IPC: C08K5/21
Filed: 1955-05-31
Abstract: A vulcanizate of low torsional hysteresis and high electrical resistivity is prepared by mixing synthetic rubber with a large amount of carbon black and with a small quantity of an aliphatic compound having two atoms of either chlorine or bromine on an aliphatic carbon atom adjacent to two carbonyl groups, heating the mixture at a temperature of at least 275 DEG  F. but below the temperature at which the rubber would be harmed by thermal decomposition, masticating the mixture during and/or after the heat treatment or alternately therewith, incorporating vulcanizing and other ingredients, shaping, and vulcanizing.  The aliphatic compound may be dichloromalonic acid, ethyl dichloromalonate, a ,a  - dichloromalonamide, a ,a  - dichloromalonyl urea, ethyl chlorobromomalonate, a ,a -dibromomalonyl urea, ethyl dibromomalonate, or a ,a -dibromomalonamide.  The synthetic rubber may comprise a polymer of a conjugated diolefin, e.g. butadiene or isoprene, or a copolymer thereof with a mono-olefin, e.g. isobutylene, styrene, a -methyl styrene, methyl or ethyl acrylate, methyl methacrylate, acrylonitrile, methacrylonitrile, methyl vinyl ketone, methyl isopropenyl ketone, or a mono-vinyl pyridine. Preferably 1 to 5 parts by weight of aliphatic compound and 40 to 100 parts of carbon black are mixed with 100 parts of synthetic rubber, and the mastication is effected at a temperature between 275 DEG  and 400 DEG  F. on a mill or in an internal mixer.  U.S.A. Specification 2,118,601 is referred to.ALSO:A vulcanizate of low torsional hysteresis and high electrical resistivity is prepared by mixing natural or synthetic rubber with a large amount of carbon black and with a small quantity of an aliphatic compound having two atoms of either chlorine or bromine on an aliphatic carbon atom adjacent to two carbonyl groups, heating the mixture at a temperature of at least 275 DEG F. but below the temperature at which the rubber would be harmed by thermal decomposition, masticating the mixture during and/or after the heat treatment or alternately therewith, incorporating vulcanizing and other ingredients, shaping and vulcanizing.  The aliphatic compound may comprise dichloromalonic acid, ethyl dichloromalonate, a -, a -dichloromalonamide, a , a -dichloromalonyl urea, ethyl chlorobromomalonate, a , a -dibromomalonyl urea, ethyl dibromomalonate, or a , a dibromomalonamide.  The synthetic rubber may comprise a polymer of a conjugated diolefin, e.g. butadiene or isoprene, or a copolymer thereof with a mono-olefin, e.g. isobutylene, styrene, a -methyl styrene, methyl or ethyl acrylate, methyl methacrylate, acrylonitrile, methacrylonitrile, methyl vinyl ketone, methyl isopropenyl ketone, or a mono-vinyl-pyridine.  Preferably 1 to 5 parts by weight of aliphatic compound and 40 to 100 parts of carbon black are mixed with 100 parts natural or synthetic rubber, and the mastication is effected at a temperature between 275 DEG  and 400 DEG F. on a mill or in an internal mixer.  In examples vulcanizates are prepared using (1) 100 parts Hevea rubber, 50 parts carbon black, 5 parts stearic acid, 2 parts a , a  dichloromalonyl urea or 3,2 parts ethyl dibromomalonate, (2) 100 parts butadienestyrene copolymer, 55 parts carbon black, 2 parts a , a -dichloromalonyl urea or 3,2 parts ethyl dibromomalonate or 2,9 parts a , a  dibromomalonyl area, (3)) 100 parts butadienestyrene copolymer, 52 parts carbon black, 6 parts hydrocarbon softener, 1 part stearic acid, 2,5 parts ethyl dibromomalonate, (4) 100 parts isobutylene-isoprene copolymer, 50 parts carbon black, 1,5 parts ethyl dibromomalonate, vulcanizing and other ingredients being added to each heat treated mixture.  U.S.A. Specification 2,118,601 is referred to.