BARRIER LAYER FOR INFLATABLE ARTICLES
A barrier layer for impeding the flow of inflation gas through an inflatable article, the barrier layer constructed of a material that is based upon a cross-linkable rubber composition, the cross-linkable rubber composition comprising, per 100 parts by weight of rubber (pbr) at least 50 phr of a primary elastomer selected from at least one of a halogenated butyl rubber or a polymeric halogenated rubber comprising C 4 to C 7 isooleiln derived units, para-alkylstyrene derived units and para-(haloalkylstyrene) derived units. The rubber composition may further include between 0 phr and 50 phr of a secondary diene elastomer and a platy filler. Additionally the rubber composition includes 1,3-phenylene dimaleimide and is cured with a sulfur curing system, which includes an accelerator.
1 . A barrier layer for impeding the flow of inflation gas through an inflatable article, the barrier layer constructed of a rubber composition that is based upon a cross-linkable elastomer composition, the cross-linkable elastomer composition comprising, per 100 parts by weight of rubber (phr):
at least 50 phr of a primary elastomer selected from at least one of a halogenated butyl rubber or a polymeric halogenated rubber comprising C 4 to C 7 isoolefin derived units, para-alkylstyrene derived units and para-(haloalkylstyrene) derived units;
between 0 phr and 50 phr of a secondary diene elastomer;
a platy filler;
at least 0.1 phr of 1,3-phenylene dimaleimide; and
a sulfur cure system having sulfur and an accelerator.
2 . The barrier layer of claim 1 , wherein the 1,3-phenylene dimaleimide is not included in the sulfur cure system.
3 . The barrier layer of claim 1 , wherein the rubber composition provides at least a 5 percent reduction in permeability as measured in accordance with ASTM D3985 at 40° C. over a second rubber composition identical to the rubber composition but for the second rubber composition having no 1,3-phenylene dimaleimide.
4 . The barrier layer of claim 1 , wherein the halogenated butyl rubber is selected from one or more of a chlorobutyl rubber or a bromobutyl rubber.
5 . The barrier layer of claim 4 , wherein the cross-linkable elastomer composition comprises 100 phr of the one or more of the chlorobutyl rubber or the bromobutyl rubber.
6 . The barrier layer of claim 1 , wherein the halogenated polymeric rubber is a halogenated poly(isobutylene-co-p-methylstyrene).
7 . The barrier layer of claim 6 , wherein the halogenated poly(isobutylene-co-p-methylstyrene) is a terpolymer of isobutylene, para-methylstyrene and brominated para-methylstyrene.
8 . The barrier layer of claim 7 , wherein the cross-linkable rub elastomer composition comprises 100 phr of the terpolymer.
9 . The barrier layer of claim 1 , wherein the secondary diene elastomer is selected from at least one of polybutadiene rubber, nitrile rubber, polyisoprene rubber, poly(styrene-co-butadiene) rubber, poly(isoprene-co-butadiene) rubber, styrene-isoprene-butadiene rubber, ethylene-propylene rubber, halogenated isoprene, halogenated isobutylene copolymers, polychloroprene or star-branched polyisobutylene rubber.
10 . The barrier layer of claim 1 , wherein the secondary diene elastomer is natural rubber.
11 . The barrier layer of claim 1 , wherein the cross-linkable elastomer composition comprises between 70 phr and 100 phr of the primary elastomer.
12 . The barrier layer of claim 1 , wherein the cross-linkable elastomer composition comprises between 0.25 phr and 3 phr of the BMI.
13 . The barrier layer of claim 1 , wherein the platy filler is an organo-modified platy filer.
14 . The barrier layer of claim 13 , wherein the platy filler is an organoclay.
15 . The barrier layer of claim 1 , wherein the cross-linkable elastomer composition comprises between 1 phr and 15 phr of the platy filler.
16 . The barrier layer of claim 1 , wherein the barrier layer is an inner tube adapted for a pneumatic tire.
17 . The barrier layer of claim 1 , wherein the barrier layer is disposed on an interior surface of the pneumatic tire.
18 . A pneumatic tire comprising a barrier layer for impeding the flow of inflation gas through the pneumatic tire, the barrier layer constructed of a rubber composition that is based upon a cross-linkable elastomer composition, the cross-linkable elastomer comprising, per 100 parts by weight of rubber (phr):
at least 50 phr of a polymeric halogenated rubber comprising C 4 to C 7 isoolefin derived units, para-alkylstyrene derived units and para-(haloalkylstyrene) derived units;
between 0 phr and 50 phr of a secondary diene elastomer;
a platy filler;
at least 0.1 phr of 1,3-phenylene dimaleimide; and
a sulfur cure system having sulfur and an accelerator.
19 . The pneumatic tire of claim 18 , wherein the halogenated polymeric rubber is a halogenated poly(isobutylene-co-p-methylstyrene).
20 . The pneumatic tire of claim 19 , wherein the halogenated poly(isobutylene-co-p-methylstyrene) is a terpolymer of isobutylene, para-methylstyrene and brominated para-methylstyrene.
21 . The pneumatic tire of claim 18 , wherein the barrier layer is disposed on an interior surface of the pneumatic tire.
22 . The pneumatic tire of claim 18 , wherein the 1,3-phenylene dimaleimide is not included in the sulfur cure system.
23 . The pneumatic tire of claim 18 , wherein the rubber composition provides at least a 5 percent reduction in permeability measured in accordance with ASTM D3985 at 40° C. over a second rubber composition identical to the rubber composition but for the second rubber composition's 1,3-phenylene dimaleimide content.
24 - 30 . (canceled)