Halogenated terpolymers of isobutylene, diolefin monomer and styrenic monomer
View Patent ↗A halogenated butyl polymer having improved properties, the butyl polymer derived from a monomer mixture comprising a C 4 to C 8 monoolefin monomer, a C 4 to C 14 multiolefin monomer and a styrenic monomer with a catalyst system to produce the butyl polymer. The improved properties include faster cure, higher maximum torque, higher delta torque, relatively stable modulus over time, improved hot air aging properties and improved aged flexure properties. These improved properties are believed to result from direct interaction between the styrenic moieties in the polymer backbone with a crosslinking agent added to vulcanize the halogenated butyl rubber.
1. A halogenated butyl terpolymer comprising a C 4 to C 8 monoolefin monomer, a C 4 to C 14 multiolefin monomer and p-methylstyrene, wherein said terpolymers is compositionally homogenous as a function of molecular weight.
2. The halogenated butyl terpolymer defined in claim 1 , wherein the C 4 to C 8 monoolefin monomer may be selected from the group comprising isobutylene, 2-methylpropene-1, 3-methylbutene-1, 4-methylpentene-1, 2-methylpentene-1, 4-ethylbutene-1, 4-ethylpentene-1 and mixtures thereof.
3. The halogenated butyl terpolymer defined in claim 1 , wherein the C 4 to C 8 monoolefin monomer comprises isobutylene.
4. The halogenated butyl terpolymer defined in claim 1 , wherein the C 4 to C 14 multiolefin monomer is selected from the group comprising isoprene, butadiene-1,3, 2,4-dimethylbutadiene-1,3, piperyline, 3-methylpentadiene-1,3, hexadiene-2,4, 2-neopentylbutadiene-1,3, 2-methlyhexadiene-1,5, 2,5-dimethlyhexadiene-2,4, 2-methylpentadiene-1,4, 2-methylheptadiene-1,6, cyclopentadiene, methylcyclo-pentadiene, cyclohexadiene, 1-vinyl-cyclohexadiene and mixtures thereof.
5. The halogenated butyl terpolymer defined in claim 3 , wherein the C 4 to C 14 multiolefin monomer comprises isoprene.
6. The halogenated butyl terpolymer defined in claim 1 , wherein the monomer mixture comprises from about 80% to about 99% by weight C 4 to C 8 monoolefin monomer, from about 0.5% to about 5% by weight C 4 to C 14 multiolefin monomer and from about 0.5% to about 15% by weight p-methylstyrene.
7. The halogenated butyl terpolymer defined in claim 1 , wherein the monomer mixture comprises from about 85% to about 99% by weight C 4 to C 8 monoolefin monomer, from about 0.5% to about 5% by weight C 4 to C 14 multiolefin monomer and from about 0.5% to about 10% by weight p-methylstyrene.
8. The halogenated butyl terpolymer defined in claim 7 , wherein the monomer mixture comprises from about 87% to about 94% by weight C 4 to C 8 monoolefin monomer, from about 1% to about 3% by weight C 4 to C 14 multiolefin monomer and from about 5% to about 10% by weight p-methylstyrene.
9. The halogenated butyl terpolymer defined in claim 1 , wherein the terpolymer is brominated.
10. The halogenated butyl terpolymer defined in claim 1 , wherein the terpolymer is chlorinated.
11. The halogenated butyl terpolymer defined in claim 1 , wherein the amount of halogen is in the range of from about 0.1 to about 8% by weight of the terpolymer.
12. The halogenated butyl terpolymer defined in claim 11 , wherein the amount of halogen is in the range of from about 0.5 to about 4% by weight of the polymer.