摘要:
A substantially gel free C.sub.4 to C.sub.7 isoolefin homopolymer rubber, butyl copolymer rubber, halogenated butyl rubber (e.g., chlorinated or brominated), or mixtures thereof, comprising a molecular weight distribution such that the ratio of the moments of said molecular weight distribution, Mz/Mw, is equal to or exceeds 2.0, and that portion of said molecular weight distribution which is equal to and greater than 4 times the peak molecular weight, Mp, comprises greater than 8 percent of the total polymer species, and Mp is greater than about 250,000 and wherein said polymer species of molecular weight less than Mp are substantially branch free. Various means are disclosed for effecting the molecular weight distribution including blending of homopolymers and/or copolymers of appropriate molecular weight and molecular weight distribution and direct polymerization using a functional reagent to introduce branching. The rubber compositions are particularly useful in applications in which butyl or halogenated butyl rubber is used and where it is desired to obtain high green strength in combination with an increased rate of stress relaxation. Such polymers are particularly well suited for use in tire innerliner compositions.
摘要:
A substantially gel free C.sub.4 to C.sub.7 isoolefin homopolymer rubber, butyl copolymer rubber, halogenated butyl rubber (e.g., chlorinated or brominated), or mixtures thereof, comprising a molecular weight distribution such that the ratio of the moments of said molecular weight distribution, Mz/Mw, is equal to or exceeds 2.0, and that portion of said molecular weight distribution which is equal to and greater than 4 times the peak molecular weight, Mp, comprises greater than 8 percent of the total polymer species, and Mp is greater than about 250,000 and wherein said polymer species of molecular weight less than Mp are substantially branch free. Various means are disclosed for effecting the molecular weight distribution including blending of homopolymers and/or copolymers of appropriate molecular weight and molecular weight distribution and direct polymerization using a functional reagent to introduce branching. The rubber compositions are particularly useful in applications in which butyl or halogenated butyl rubber is used and where it is desired to obtain high green strength in combination with an increased rate of stress relaxation. Such polymers are particularly well suited for use in tire innerliner compositions.
摘要:
Ozone resistant vulcanizable copolymers of isoolefins with non-conjugated dienes of the general formula: ##STR1## where R.sub.1 is ##STR2## and R.sub.2 is alkyl of 1 to 6 carbon atoms and vulcanizates thereof. The copolymers are prepared by polymerization in the presence of Lewis acids.
摘要:
Vulcanizable tire innerliner compositions are described which are essentially free of halogen atoms or contain a reduced halogen content. The innerliners contain a saturated elastomeric interpolymer of a C.sub.4 -C.sub.7 isomonoolefin, e.g., isobutylene and a para-alkylstyrene e.g., para-methylstyrene, which contains benzylic ester functionality having the structure: ##STR1## wherein R.sub.2 and R.sub.3 are independently selected from hydrogen or C.sub.1 to C.sub.6 alkyl, and R.sub.4 is selected from hydrogen, C.sub.1, to C.sub.28 alkyl, aryl or C.sub.2 to C.sub.28 alkenyl.Innerliners of the invention provide excellent impermeability to air, heat aging properties and good adhesion to tire carcass stock required for tire innerliners, and are also essentially free of halogen or contain low halogen content thereby reducing environmental concerns occasioned by the incineration of used tires.
摘要:
A process for halogenating star-branched butyl rubber is provided wherein water and a wetting agent or wetting agent precursor are added to a solution comprising the star-branched butyl rubber, solid particles of branching agent and an organic solvent prior to the neutralization step to increase the rate of neutralization of the hydrogen halide by-product of the halogenation reaction.
摘要:
An additive for latex rubber compounds is provided, the additive comprising crosslinked fatty acid and preferably lightweight microcellular filler, preferably expanded perlite. The additive is prepared as an aqueous emulsion and increases tear resistance in latex rubber compounds.
摘要:
A partially crosslinked, unsaturated elastomeric polymer of a C.sub.4 to C.sub.7 isomonoolefin and a C.sub.4 to C.sub.14 conjugated multiolefin is provided which has a low crosslink density. The partially crosslinked polymer is produced by curing an uncrosslinked unsaturated polymer having a low level of chemically bound halogen with a curing agent which reacts only with the halogen. Processes for preparing these partially crosslinked unsaturated polymers are also provided.
摘要:
This invention provides for curable and graft-cured polymer compositions prepared from a mixture comprising:a) an elastomeric copolymer containing from about 0.01 up to about 10 mole % of Y ester groups randomly distributed along and pendant to the elastomeric polymer chain, said Y ester groups having the structure: ##STR1## wherein R.sub.2 and R.sub.3 are independently selected from the group consisting of hydrogen and an alkyl group containing 1 to about 6 carbon atoms and R.sub.4 is selected from the group consisting of hydrogen, an alkyl group containing from 1 to about 28 carbon atoms, an aryl group and an alkenyl group containing from 2 to about 28 carbon atoms; andb) at least one free radically polymerizable monomer. The invention also provides for a process for preparing graft-cured polymer compositions comprising forming the above recited mixture of (a) and (b) and subjecting said mixture to free radical polymerization conditions. The Y ester groups pendant to the elastomeric polymer chain, e.g. benzylic(meth)acrylic acid ester groups present in isobutylene/para-methystyrene interpolymer chains, are capable of participating in free radical initiated reactions with monofunctional or polyfunctional free radically polymerizable monomers to produce graft-crosslinked compositions having an unusual balance of physical properties. These compositions may be formed into shaped articles such as films, coatings, adhesive layers and moldings and subjected to free radical polymerization conditions to produce crosslinked shaped articles.
摘要:
A tire sidewall composition having improved properties is provided. The composition comprises a halogen-containing copolymer of a C.sub.4 to C.sub.7 isomonoolefin and a para-alkylstyrene, and an unsaturated rubber, such as natural rubber. Tires comprising the sidewalls are also provided.
摘要:
A hose composition is provided which comprises a halogen-containing copolymer of a C.sub.4 to C.sub.7 isomonoolefin and a para-alkylstyrene, fillers, rubber compounding additives and a curing agent. A hose comprising at least a portion made from this hose composition is also provided.