WO2008004998A1

WO2008004998A1 - Elastomeric air barrier composition and use thereof

Info

Publication number: WO2008004998A1
Application number: PCT/US2006/025380
Authority: WO
Inventors: Yoshihiro Soeda; Andy Haishung Tsou
Original assignee: The Yokohama Rubber Co., Ltd.; Exxonmobil Chemical Patents Inc.
Priority date: 2006-06-29
Filing date: 2006-06-29
Publication date: 2008-01-10

Abstract

A fluid barrier composition useful in industrial articles such as motor vehicle and aircraft tire innerliners and innertubes, tire curing bladders and hoses prepared from a mixture comprising: (A) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a polymerized isomonoolefin containing from 4 to 12 carbon atoms and about 0.5. to about 20 wt% of monomer units of (a) at least one C4 to C14 multiolefin; or (b) at least one para-alkylstyrene,- or (c) a mixture of at least one of (a) and at least one of (b) ; (B) about 0.5 to about 20 wt% of at least one block copolymer of styrene derived monomer units and C4 to C10 conjugated diene derived monomer units; (C) about 20 to about 45 Wt% of a filler, (D) greater than 0 to about 25 wt % of a plasticizer oil; and (E) about 1 to about 10 wt% of a curing system for said interpolymer. Preferably the block copolymer is an epoxidized styrene-butadiene-styrene block copolymer including an oxirane oxygen group.

Description

ELASTOMERIC AIR BARRIER COMPOSITION AND USE THEREOF

FIELD OF THE INVENTION

[0001] This invention relates to a fluid barrier composition prepared from a minture comprising an isobutylene based polymer, a styrenic block copolymer, filler, plasticizer oil; and a curing system.

BACKGROUND OF THE INVENTION

[0002] Elastomer compositions are useful for tire, innertube, curing bladder and other industrial rubber applications requiring good air or fluid holding properties, particularly those in which improved low temperature performance is required. Butyl rubber, i.e., elastomeric copolymers of isobutylene with up to about 10 wt% of isoprene, possesses excellent resistance to air permeability and good aging properties which render it quite suitable for use as tire innertubes, innerliners for the production of tubeless pneumatic tires, tire curing bladders, etc. An innerliner is generally composed of a relatively thin sheet of an elastomeric composition typically comprising rubber compounding ingredients such as fillers, plasticizers, and other additives and a curing system. The innerliner is laminated to the inner surface of a tire carcass layer of an uncured tire as the tire is formed on a tire building drum. Curing or vulcanization of the composite structure produces a tire having a cured innerliner adhered to the carcass which serves as a barrier to the passage of pressurized air through the tire.

[0003] Halogenated butyl rubber typically containing about 0.5 to about 3 wt% halogen, e.g., bromine or chlorine, has proven to be a more effective elastomer for use in an innerliner because the halogenated polymer exhibits improved adhesion to the tire carcass material/ among other things. The halogenated elastomer can be formulated with a curative composition or system, e.g., zinc oxide and. sulfur curing agents, which contribute to the development of interfacial crosslinking between the surface of the innerliner layer and the surface of the adjacent carcass layer which normally contains a more- highly unsaturated rubber, thereby enhancing adhesion of the innerliner to the carcass. The use of halogenated butyl rubber for tire innerliners is disclosed in U.S. Pat. No. 2,943,664, incorporated herein in its entirety, as well as numerous other patents.

[0004] More recently, a new class of halogenated C₄-C₇ isomonoolefin elastomers have been developed which demonstrate superior heat aging and flex properties as compared with halogenated butyl rubber. These polymers comprise random interpolymers of C^-C₇ isomonoolefin, such as isobutylene, with up to about 20 wt% of a para- alkylstyrene, such as para-znethylstyrene, containing about 0.1 to about 5 mol% of halomethylstyrene groups, e.g., bromomethylstyrene groups. These elastomers are more resistant to heat aging because they are free of olefinic unsaturation and yet they provide the good resistance to air permeability, as well as good flex resistance, tensile strength elongation and adhesion properties desired for various industrial applications, particularly tire innerliner applications. These polymers may also be cured by facile crosslinking reactions involving the benzylic halogen atom using zinc oxide and sulfur curing systems similar to those used to cure halogenated butyl rubber. These halogenated polymers are further described in U.S. Pat. No. 5,162,445 and compositions containing these polymers used for the fabrication of tire innerliners are disclosed in U.S. Pat. No. 5,333,662 and U, S. Pat. No. 5,386,864, each incorporated herein by reference in their entirety. ■ .0005] Further improvements in the low temperature performance of compositions exhibiting improved fluid (gas or liquid) barrier properties as well as desirable levels of strength and flexibility suitable for use in tires and hose applications can be accomplished by use of the compositions of the present invention. SUMMARY OF THE INVENTION

[0006] An embodiment of this invention relates to a fluid barrier composition prepared from a mixture comprising. (A) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a polymerized isomonoolefin containing from 4 to 12 carbon atoms and about 0.5 to about 20 wt% of monomer units of (a) at least one C4 to C^ multiolefin; or (b) at least one para- alkylstyrene/ or (c) a mixture of at least one of (a) and at least one of (b) ; (B) about 0.5 to about 20 wt% of at least one block copolymer of styrene derived monomer units and C4 to do conjugated diene derived monomer units; (C) about 20 to about 45 wt % of a filler, (D) greater than 0 to about 25 wt % of a plasticizer oil_/ and (E) about 1 to about 10 wt% of a curing system for said interpolymer. The fluid barrier can be employed, for example, in various industrial articles such as motor vehicle innerliners and innertubes, aircraft tire innerliners and innertubes, tire curing bladders and hoses. f0007] Alternatively, another embodiment of the invention is directed to a process for fabricating a pneumatic tire comprised of at least one carcass element comprising at least one unsaturated rubber and at least one innerliner element adhered to said at least one carcass element comprising: (A) forming into an innerliner sheet a composition comprising a mixture of: (a) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a polymerized isomonoolefin containing from 4 to 12 carbon atoms and about 0.5 to about 20 wt% of monomer units of (i) at least one C₄ to Cu multiolefin; or (ii) at least one para-alkylstyrene; or (iii) a mixture of at least one of (i) and at least one of (ii); (b) about 0.5 to about 20 wt% of at least one block copolymer of styrene derived monomer units and Cj to Cio conjugated diene derived monomer units; (c) greater than 0 to about 30 wt% of a polymer selected from the group consisting of natural rubber, polyisoprena and polybutadiene rubber; (d) about 20 to about 45 wt % of at least one filler, (e) greater than 0 to about 25 wt % of a plasticizer oil; and (f) at least 1 wt % of a curing system for said interpolymer; (B) contacting said innerliner sheet material with said at least one tire carcass element to form a laminated structure; and (C) heating said structure at a temperature of from about 100 ⁰C to about 250 ⁰C for a period of time sufficient to vulcanize said structure. In a particularly preferred embodiment, the block copolymer is an epoxidized styrene- butadiene-styrene block copolymer including an oxirane oxygen group, DETAILED DESCRIPTION

[0008] The present invention relates to applications utilizing elastomeric compositions for tire innerliners and innertubes, including those used in automobiles, trucks, buses, and aircraft; tire curing bladders; hoses and barrier films. More particularly, the applications relate to elastomeric compositions exhibiting excellent impermeability to fluids such as air as well as liquids and improved low temperature performance. Preferred compositional features include the use of styrenic block copolymers or derivatives of such copolymers in, combination with halogenated isobutylene elastomers and optionally including natural rubber. Furthermore, the invention includes processes for producing pneumatic tires and other articles using the above compositions. The preferred elastomers exhibit low-permeability and are preferably a polymer such as halogenated isobutylene- containing elastomers, particularly brominated elastomers, especially brominated paramethylstyrene-σo- isobutylene polymers (BIMS) ; preferred are bromobutyl elastomers exhibiting high content of the structure illustrated hereinafter below. Also preferred are commercial bromobutyl elastomers,, or blends thereof with one or more of the aforementioned brominated elastomers with one another or with other polymers as will be described in detail below,

[0009] The following definitions and explanations shall apply throughout the entire specification including the disclosure and claims:

[0010] The new numbering scheme for the Periodic Table Groups is used herein, the scheme as disclosed in Chemical and Engineering News, 63(5), 27 (1985), tOOll] All molecular weights are weight average unless otherwise noted.

[0012J The word "comprise" and variations of the word, such as "comprising" and "comprises," as well as "have," "having," "includes," "include" and "including," and variations thereof, means that the named steps, elements or materials to which it refers are essential, but other steps, elements or materials may be added and still form a construct with the scope of the claim or disclosure. When recited in describing the invention and in a claim, it means that the invention and what is claimed is considered to what follows and potentially more. These terms, particularly when applied to claims, are inclusive or open-ended and do not exclude additional, unrecited elements or methods steps.

[0013] The phrase "consisting essentially of" is meant to exclude any element or combination of elements, as well as any amount of any element or combination of elements that would alter the basic and novel characteristics of the invention. Thus, by way of examples only, an elastomeric composition that does not include the use of a styrenic block copolymer as hereinafter described or in which high diene rubber or other polymer or polymer combination is used to the exclusion of isobutylene-containing rubber in such a composition, would be excluded.

[0014] For purposes of the present invention, unless otherwise defined with respect to a specific property, characteristic or variable, the term "substantially" as applied to any criteria, such as a property, characteristic or variable, means to meet the stated, criteria in such measure such that one skilled in the art would understand that the benefit to be achieved, or the condition or property value desired is met, [0015] Polymer may be used to refer to homopolymers, copolymers, interpolymers, terpolymers, etc. Likewise, a copolymer may refer to a polymer comprising at least two monomers, optionally with other monomers, [0016] When a polymer is referred to as comprising a monomer, the monomer is present in the polymer in the polymerized form of the monomer or in the derivative form of the monomer. However, for ease of reference the phrase "comprising the (respective) monomer" or the like is used as shorthand. Likewise, when catalyst components are described as comprising neutral stable forms of the components, it is well understood by one of ordinary skill in the art, that the active form of the component is the form that reacts with the monomers to produce polymers,

[0017] Isoolefin refers to any olefin monomer having two substitutions on the same carbon,

[0018] Multiolefin refers to any monomer having two or more double bonds. In a preferred embodiment, the multiolefin is any monomer comprising two double bonds, preferably two conjugated double bonds such as a conjugated diens like isoprene.

[0019] Elastomer or elastomers as used herein, refers to any polymer or composition of polymers consistent with the definition in the standard identified as ASTM D1566. The terms may be used interchangeably with the term "rubber" or "rubbers." [0020] Alkyl refers to a paraffinic hydrocarbon group which may be derived from an alkane by dropping one or more hydrogens from the formula, such as, for example, a methyl group (CH3) , or an ethyl group (CHsCH₂), etc. [0021] Aryl refers to a hydrocarbon group that forms a ring structure characteristic of aromatic compounds such as, for example, benzene, naphthalene, phenanthrene, anthracene, etc., and typically possess alternate double bonding ("unsaturation") within its structure. An aryl group is thus a group derived from an aromatic compound by dropping one or more hydrogens from the formula such as, for example, phenyl, or CβHs.

[0022] Substituted refers to at least one hydrogen group being replaced by at least one substituent selected from, for example, halogen (chlorine, bromine, fluorine, or iodine) , amino, nitro, sulfoxy (sulfonate or alkyl sulfonate) , thiol, alkylthiol, and hydroxy; alkyl, straight or branched chain having 1 to 20 carbon atoms which includes methyl, ethyl, propyl, tert-butyl, isopropyl, isobutyl, etc.; alkoxy, straight or branched chain alkoxy having 1 to 20 carbon atoms, and includes/ for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, secondary butoxy, tertiary butoxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, and deσyloxy; haloalkyl, which means straight or branched chain alkyl having 1 to 20 carbon atoms which contains at least one halogen, and includes, for example, σhloromethyl, bromomethyl, fluoromethyl, iodomethyl, 2- chloroethyl, 2-bromoethyl, 2-fluoroethyl, 3-chloropropyl, 3-bromopropyl, 3-fluoroρropyl, 4-chlorobutyl, 4- fluorøbutyl, dichloromethyl, dibromomethyl, difluoromethyl, diiodomethyl, 2,2-dichloroethyl, 2,2- dibromomethyl, 2,2-difluoroethyl, 3, 3-dichloropropyl, 3,3-difluoropropyl, 4, 4-diσhlorobutyl, 4, 4-difluorobutyl, trichloromethyl, 4, 4-difluorobutyl, trichloromethyl_/ trifluoromethyl, 2,2,2-trifluoroethyl, 2,3₇3- trifluoropropyl, 1, 1,2,2-tetrafluoroethyl, and 2,2,3,3- tetrafluoropropyl. Thus, for example, a "substituted styrenic unit" includes p-methylstyrene, p-ethylstyrene, etc.

[0023] The present invention comprises at least one isobutylene-containing rubber, preferably a halogenated form of such rubber, more preferably brominated. Typically, it is present in a composition with a styrenic block copolymer as described herein. Halogenated rubber is defined as a rubber having at least about 0.1 mol% halogen, such halogen selected from the group consisting of bromine, chlorine and iodine. Preferred halogenated rubbers useful in this invention include halogenated isobutylene containing elastomers (also referred to as halogenated isobutylene-based homopolymers or copolymers) These elastomers can be described as random copolymer of a C4 to C₇ isomonoolefin derived unit, such as isobutylene derived unit, and at least one other polymerizable unit, In one embodiment of the invention, the halogenated isobutylene-based copolymer is a butyl-type rubber or branched butyl-type rubber, especially brominated versions of these elastomers. (Useful unsaturated butyl rubbers such as homopolymers and copolymers of olefins or isoolefins and other types of elastomers suitable for the invention are well known and are described in Rubber Technology pg. 209-581 (Maurice Morton ed., Chapman & Hall 1995), The Vanderbilt Rubber Handbook 105-122 (Robert F. Ohm ed., R.T. Vanderbilt Co., Inc. 1990), and Edward Kresge and B.C. Wang in 8 Kirk-Othmer Encyclopedia of Chemical Technology 934-955 (John Wiley & Sons, Inc. 4th ed. 1993)) .

[0024] Butyl rubbers are typically prepared by reacting a mixture of monomers, the mixture having at least (1) a C₄ to Ciz isoolefin monomer component such as isobutylene with (2) a multiolefin monomer component. The isoolefin is in a range from 70 to 99.5 wt% by weight of the total monomer mixture in one embodiment, and 85 to 99.5 wt% in another embodiment. The multiolefin component is present in the monomer mixture from 30 to 0.5 wt% in one embodiment, and from.15 to 0.5 wt% in another embodiment. In yet another embodiment, from 8 to 0.5 wt% of the monomer mixture is multiolefin. The isoolefin is preferably a C₄ to C₁₂ compound, mon-limiting examples of which are compounds such as isobutylene, isobutene, 2-methyl-l-butene, 3-methyl-l-butene, 2- methyl-2-butene, 1-butene, 2-butene, methyl vinyl ether, indene, vinyltrimethylsilane, hexene, and 4-methyl-l- pentene. The multiolefin is a C₄ to C₁₄ multiolefin such as isoprene, butadiene, 2,3~dimethyl-l,3-butadiene, myrcene, 6, 6-dimethyl-fulvene, hexadiene, cyclopentadiene, and piperylene, and other monomers such as disclosed in ElP 279456 and U.S. Patent Nos. 5,506,316 and 5,162,425. Other polymerizable monomers such as styrene and dichlorostyrene are also suitable for homopolymerization or copolymerization in butyl rubbers. One embodiment of the butyl rubber polymer useful in the invention is obtained by reacting 95 to 99,5 wt% of isobutylene with 0.5 to 8 wt% isoprene, or from 0.5 wt% to 5.0 wt% isoprene in yet another embodiment. Butyl rubbers and methods of their production are described in detail in, for example, U.S. Patent Nos. 2,356,128, 3,968,076, 4,474,924, 4,068,051 and 5,532,312. [0025] Halogenated butyl rubber is produced by the halogenation of the butyl rubber product described above. Halogenation can be carried out by any means, and the invention is not herein limited by the halogenation process. Methods of halogenating polymers such as butyl polymers are disclosed in U.S. Pat. Nos. 2,631,984, 3,099,644, 4,288,575, 4,554,326, 4,632,963, 4,681,921, 4,650,831, 4,384,072, 4,513,116 and 5,681,901. In one embodiment, the butyl rubber is halogenated in hexane diluent at from 4 to 60 °C using bromine (Br₂) or chlorine (Cl₂) as the halogenation agent. Post-treated halogenated butyl rubber can also be used, as disclosed in U.S. Pat. No. 4,288,575. Useful halogenated butyl rubber typically has a Mooney Viscosity of about 20 to about 70 (ML 1+8 at 125°C) ; for example, and about 25 to about 55 in another embodiment-. The preferred halogen content is typically about 0.1 to 10 wt% based on the weight of the halogenated rubber; for example, about 0.5 to 5 wt%; alternatively, about 0.8 to about 2.5 wt%; for example, about 1 to about 2 wt%, A particularly preferred form of halogenated butyl rubber contains a high content of the following halogenated structure (I) (preferably 60 to 95% as measured by NMR) , where X represents the halogen and, in a particularly preferred embodiment, the halogen is bromine; alternatively the halogen is chlorine:

~f—CH₂-C-CH-CH₂-*- (I)

X

[0026] A commercial embodiment of a halogenated butyl rubber useful in the present invention is Bromobutyl 2222 (ExxonMobil Chemical Company, Baytown, Texas) . Its Mooney Viscosity is typically about 27 to 37 (ML 1+8 at 125⁰C, ASTM 1646, modified), and its bromine content is about 1.8 to 2.2 wt% relative to the Bromobutyl 2222. Furthermore, the cure characteristics of Bromobutyl 2222 as provided by the manufacturer are as follows: MH about 28 to 40 dN m, ML is about 7 to 18 dN m (ASTM D2084) . Another commercial embodiment of the halogenated butyl rubber useful in the present invention is Bromobutyl 2255 (ExxonMobil Chemical Company) . Its Mooney Viscosity is about 41 to 51 (ML 1+8 at 125⁰C, ASTM D164.6) , and its bromine content is about 1.8 to 2.2 wt%. Furthermore, its cure characteristics as disclosed by the manufacturer are as follows: MH is from 34 to 48 dN m, ML is from 11 to 21 dN m (ASTM D2084). Useful commercial isobutylene polymers are described in detail by R.N. Webb, T.D, Shaffer and A.H. Tsou, "Commercial Isobutylene Polymers," Encyclopedia of Polymer Science and Technology, 2002, John Wiley & Sons, incorporated herein by reference. [0027] Another useful embodiment of halogenated butyl rubber is halogenated, branched or "star-branched" butyl . rubber- These rubbers are described in, for example, EP 678529 Bl, U.S. Pat. Nos. 5,182,333 and 5,071,913, each incorporated herein by reference. In one embodiment, the star~branched butyl rubber ("SBB") is a composition comprising butyl rubber and a polydiene or block copolymer. For purposes of the present invention, the method of forming the SBB is not a limitation. The polydienes, block copolymer, or branching agents (hereinafter "polydienes") , are typically cationically reactive and are present during the polymerization of the butyl or halogenated butyl rubber, or can be blended with the butyl rubber to form the SBB. The branching agent or polydiene can be any suitable branching agent, and the invention is not limited to the type of polydiene or branching agent used to make the SBB.

[0028] In one embodiment, the SBB is a composition of butyl or halogenated butyl rubber as described above and a' copolymer of a polydiene and a partially hydrogenated polydiene selected from the group consisting of styrene, polybutadiene, polyisoprene, polypiperylene, natural rubber, styrene-butadiene rubber, ethylene-propylene diene rubber (EPDM) , ethylene-propylene rubber (EPM) , styrene-butadiene-styrene and styrene-isoprene-styrene block copolymers. Polydienes can be present, based on the total monomer content in wt%, typically greater than 0.3 wt%/ alternatively, about 0.3 to about 3 wt%;.or about 0.4 to 2.7 wt%.

[0029] Preferably the branched or "star-branched" butyl rubber used herein is halogenated. In one embodiment, the halogenated star-branched butyl rubber ("HSBB") comprises a butyl rubber, either halogenated or not, and a polydiene or block copolymer, either halogenated or not. The halogenation process is described in detail in U.S. Pat. Nos. 4,074,035; 5,071,913; 5,286,804; 5,182,333; and 6,228,978. The present invention is not limited by the method of forming the HSBB, The polydiene/block copolymer, or branching agents (hereinafter "polydienes") , are typically cationiσally reactive and are present during the polymerization of the butyl or halogenated butyl rubber, or can be blended with the butyl or halogenated butyl rubber to form the HSBB. The branching agent or polydiene can be any suitable branching agent, and the invention is not limited by the type of polydiene used to make the HSBB.

[0030] In one embodiment, the HSBB is typically a composition comprising halogenated butyl rubber as described above and a copolymer of a polydiene and a partially hydrogenated polydiene selected from the group consisting of styrene, polybutadiene, polyisoprene, polypiperylene, natural rubber, styrene-butadiene rubber, ethylene-propylene diene rubber, styrene-butadiene- styrene and styrene-isoprene-styrene block copolymers. Polydienes can be present, based on the total monomer content in wt%, typically greater than about 0.3 wt%, alternatively about 0.3 to 3 wt%, or about 0.4 to 2.7 wt%.

[0031] A commercial embodiment of HSBB useful in the present invention is Bromobutyl 6222 (ExxonMobil Chemical Company, Baytown, Texas) , having a Mooney Viscosity (ML 1+8 at 12S⁰C, ASTM D1646) of about 27 to 37, and a bromine content of about 2.2 to 2.6 wt%. Further, cure characteristics of Bromobutyl 6222, as disclosed by the manufacturer, are as follows: MH is from 24 to 38 dN m, ML is from 6 to 16 dN m (ASTM D2084) . [0032] Preferred isoolefin/para-alkylstyrene copolymers useful herein include random copolymers comprising a C₄ to C₇ isoolefin, such as isobutyleηe, and a halomethylstyrene. The haloraethylstyrene may be an ortho-, roeta-, or para-alkyl-substituted styrene. In one embodiment, the halomethylstyrene is a p- halomethylstyrene containing at least 80%, more preferably at least 90% by weight of the para-isomer. The "halo" group can be any halogen, desirably chlorine or bromine. The copolymer may also include functionalized interpolymers wherein at least some of the alkyl substituent groups present on the styrene monomer units contain bensylic halogen or another functional group described further below. These interpolymers are herein referred to as "isσolefin copolymers comprising a halomethylstyrene" or simply "isoolefin copolymer." [0033] Preferred isoolefin copolymers can include monomers selected from the group consisting of isobutylene or isobutene, 2-methyl-1-butene, 3-methyl-l- butene, 2-methyl-2-butene, 1-butene, 2-butene, methyl vinyl ether, indene, vinyltrimethylsilane, hexene, and 4- methyl-1-pentene. Preferred isoolefin copolymers may also further comprise multiolefins, preferably a C₄ to Ci^ multiolefin such as isoprene, butadiene, 2,3-dimethyl- 1,3-butadiene, myrcene, 6,6-dimethyl-fulvene, hexadiene, cyσlopentadiene, and piperylene, and other monomers such as disclosed in EP 279456 and U.S. Pat. Nos. 5,506,316 and 5,162,425. Desirable styrenic monomers in the isoolefin copolymer include styrene, methylstyrene, chlorostyrene, methoxystyrene, indene and indene derivatives, and combinations thereof. [0034] Preferred isoolefin copolymers may be characterized as interpolymers containing the following monomer units 1 and 2 randomly spaced along the polymer chain:

wherein R and R₁ are independently hydrogen, lower alkyl, preferably C₁ to C₇ alkyl and primary or secondary alkyl halides and X is a functional group such as halogen- Desirable halogens are chlorine, bromine or combinations thereof, preferably bromine_* Preferably R and Ri are each hydrogen. The -CRRiH and -CRRiX groups can be substituted on the styrene ring in either the ortho, meta, or para positions, preferably the para position. Up to 60 moX% of the p-substituted styrene present in the interpolymer structure may be the fun-ctionalized structure (2) above in one embodiment, and in another embodiment from (Ll to 5 mol%. In yet another embodiment, the amount of functionalized structure (2) is from, 0.4 to 1 mol%. The functional group X may be halogen or some other functional group which may be incorporated by nucleophilic substitution of benzylic halogen with other groups such as carboxylic acids; carboxy salts; carboxy esters, amides and imides; hydroxy; alkσxide; phenoxide; thiolate; thioether; xanthate; cyanide; cyanate; amino and mixtures thereof. These functionalized isomonoolefin copolymers, their method of preparation, methods of funσtionalization and cure are more particularly disclosed in U.S. Pat. No. 5,162,445, incorporated herein in its entirety by reference.

[0035] Particularly useful of such copolymers of isobutylene and p-methylstyrene are those containing from 0.5 to 20 mol% p-methylstyrene wherein up to 60 mol% of the methyl substituent groups present on the benzyl ring contain a bromine or chlorine atom, preferably a bromine atom (p-bromomethylstyrene) , as well as acid or ester functionalized versions thereof wherein the halogen atom has been displaced by maleic anhydride or by acrylic or methacrylic acid functionality. These interpolymers are termed "halogenated poly (isobutylene-σo-p-methylstyrene) " or "brominated poly (isobutylene-co-p-methylstyrene) ", and are commercially available under the name EXXPRO™ Elastomers (ExxonMobil Chemical Company, Houston, TX) . It is understood that the use of the terms "halogenated" or "brominated" are not limited to the method of halogenation of the copolymer, but merely descriptive of the copolymer which comprises the isobutylene derived units, the p-methylstyrene derived units, and the p- halomethylstyrene derived units .

[0036] These funσtionalized polymers preferably have a substantially homogeneous compositional distribution such that at least 95% by weight of the polymer has a p- alkylstyrene content within 10% of the average p- alkylstyrene content of the polymer as measured by gel permeation chromatography (as shown in U.S. Pat. No. 5,162,445). More preferred polymers are also characterized by a narrow molecular weight distribution (Mw/Mn) of less than 5, more preferably less than 2.5, a preferred viscosity average molecular weight in the range of about 200,000 to about 2,000,000 and a preferred number average molecular weight in the range of about 25,000 to about 750,000 as determined by gel permeation chromatography.

[0037] Preferred halogenated poly{isobutylene-co-p- methyl≥tyrene) polymers are brominated polymers which generally contain from about 0.1 to about 5 wt% of bromomethyl groups, In yet another embodiment, the amount of bromomethyl groups is about 0.2 to about 2.5 wt%. Expressed another way, preferred copolymers contain about 0.05 to about 2.5 mol% of bromine, based on the weight of the polymer, more preferably about 0.1 to about 1.25 mol% bromine, and are substantially free of ring halogen or halogen in the polymer backbone chain. In one embodiment of the invention, the interpolymer is a copolymer of C₄ to C₇ isomonoolefin derived units, p- methylstyrene derived units and p-halomethylstyrene derived units, wherein the p-halomethylstyrene units are present in the interpolymer from about 0.4 to about 1 mol% based on the interpolymer. In another embodiment, the p-halomethylstyrene is p-bromomethylstyrene. The Mooney Viscosity (1+8, 125°C, ASTM D1646) is about 30 to about 60 Mooney units. [0038] In another embodiment, the relationship between the triad fraction of an isoolefin and a p-alkylstyrene and the mσl% of p-alkylstyrene incorporated into the copolymer is described by the copolymer sequence distribution equation described below and is characterized by the copolymer sequence distribution parameter, m.

F = I - {m A / (1 + mA)} where: in is the copolymer sequence distribution parameter,

A is the molar ratio of p-alkylstyrene to isoolefin in the copolymer and,

F is the p-aljcylstyrene-isoolefin-p-alkylstyrene triad fraction in the copolymer.

[0039] The best fit of this equation yields the value of m for copolymer!zation of the isoolefin and p- alkylstyrene in a particular diluent. In certain embodiments, m is from less than 38; alternatively, from less than 36; alternatively, from less than 35; and alternatively, from less than 30. In other embodiments, m is from 1-38; alternatively, from 1-36; alternatively, from 1-35; and alternatively from 1-30. Copolymers having such characteristics are disclosed in WO 2004058825 and WO 2004058835.

[0040] In another embodiment, the isoolefin/para- alkylstyrene copolymer is substantially free of long chain branching. For the purposes of this invention, a polymer that is substantially free of long chain branching is defined to be a polymer for which g'vis.avg. is determined to be greater than or equal to 0.978, alternatively, greater than or equal to 0.980, alternatively, greater than or equal to 0.985, alternatively, greater than or equal to 0.990, alternatively, greater than or equal to 0.995, alternatively, greater than or equal to 0.998, alternatively, greater than or equal to 0.999, as determined by triple detection size exclusion chromatography (SEC) as described below. Such polymers are also disclosed in WO 2004058825 and WO 2004058835. [0041] In another embodiment, the relationship between the triad fraction of an isoolefin and a multiolefin and the mol% of multiolefin incorporated into' the halogenated rubber copolymer is described by the copolymer sequence distribution equation below and is characterized by the copolymer sequence distribution parameter, m.

F = m A / {1 + inA)² where: m is the copolymer sequence distribution parameter,

A is the molar ratio of multiolefin to isoolefin in the copolymer and,

IT is the isoolefin-multiolefin-multiolefin triad fraction in the copolymer.

[0042] Measurement of triad fraction of an isoolefin and a multiolefin and the mol% of multiolefiπ incorporated into the copolymer is described below. The best fit of this equation yields the value of m for copolymerization of the isoolefin and multiolefin in each diluent. In certain embodiments, m is from greater than 1.5; alternatively, from greater than 2.0; alternatively, from greater than 2.5; alternatively, from greater than 3.0; and alternatively, from greater than 3.5. In other embodiments, m is from 1,10 to 1,25; alternatively, from 1.15 to 1.20; alternatively, from 1.15 to 1.25; and alternatively, m is about 1.20. Halogenated rubbers that have these characteristics are disclosed in WO 2004Q58S25 and WO 2004058835.

[0043] In another embodiment, the halogenated rubber is substantially free of long chain branching. For the purposes of this invention, a polymer that is substantially free of long chain branching is defined to be a polymer for which g'vis.av^. is determined to be greater than or equal to 0,978, alternatively, greater than or equal to 0,980, alternatively, greater than or equal to 0.985, alternatively, greater than or equal to 0.990, alternatively, greater than or equal to 0.995_r alternatively, greater than or equal to 0.998, alternatively, greater than or equal to 0.999, as determined by triple detection SEC as follows. The presence or absence of long chain branching in the polymers is determined using triple detection SEC. Triple detection SEC is performed on a Water$ (Milford, Massachusetts) 150C chromatograph operated at 40⁴¹C equipped a Precision Detectors (Bellingham, Massachusetts) PD2040 light scattering detector, a Visσotek (Houston, Texas) Model 150R viscometry detector and a Waters differential refractive index detector (integral with the 150C) . The detectors are connected in series with the light scattering detector being first, the viscometry detector second^' and the differential refractive index detector third. Tetrahydrofuran is used as the eluent (0.5 ml/rnin.) with a set of three Polymer Laboratories, Ltd. (Shropshire, United Kingdom) 10 micron mixed-B/LS GPC columns. The instrument is calibrated against 16 narrow polystyrene standards (Polymer Laboratories, Ltd.). Data is acquired with TriSEC software (Viscotek) and imported into WaveMetric's Igor Pro program (Lake Oswego, OR) for analysis. Linear polyisobutylene is used to establish the relationship between the intrinsic viscosity [α]ii_Λear determined by the visσometry detector) and the molecular weight (M_w, determined by the light scattering detector) . The relationship between [αlun_ear and M_w is expressed by the Mark-Houwink equation.

[K] linear = KM_W"

[0044] Parameters K and α are obtained from the double-logarithmic plot of intrinsic viscosity against M_Wf cc is the slope, K the intercept. Significant deviations from the relationship established for the linear standards indicate the presence of long chain branching. Generally, samples which exhibit more significant deviation from the linear relationship contain more significant long chain branching. The scaling factor g¹ also indicates deviations from the determined linear relationship.

[CO sample =* g' IOC3linear

[0045] The value of g¹ is defined to be less than or equal to one and greater than or equal to zero. When g' is equal or nearly equal to one, the polymer is considered to be linear. When g¹ is significantly less than one, the sample is long chain branched. See e.g. E. F. Casassa and G.C. Berry in "Comprehensive Polymer Science," Vol. 2, (71-120) G. Allen and J. C. Bevington, Ed. , Pergamon Press, New York, 1988. In triple detection SEC, a g' is calculated for each data slice of the chromatographic curve. A viscosity average g' or g\χ_3τlχvg, is calculated across the entire molecular weight distribution. The scaling factor g'vis.avg. is calculated from the average intrinsic viscosity of the sample: gWavg. = [αW / (KM/))

[0046] Other preferred halogenated elastomers or rubbers include halogenated isobutylene terpolymers such as isobutylene~p-methylstyrene-isoprene copolymers, such elastomers and their methods of preparation as described in U.S.^' Patent No. 6,960,632 or WO 01/21672A1, incorporated herein by reference.

[0047] The isobutylene-containing elastomers used in the elastomeric compositions useful as fluid permeation prevention layer as described herein may be the same or different as halogen containing elastomers present in other layers of the article being manufactured. For example if the fluid permeation layer is present as a ^■ tire innerliner layer, then the other layers of the tire, particularly those in contact with the innerliner layer may also contain the same isobutylene-containing elastomers. Likewise, the halogenated isobutylene containing elastomer useful in the air permeation prevention layer and the elastomer useful in a tie layer, adhesive layer, and/or one or more tire carcass layers may be the same or different elastomer. In a preferred embodiment, the halogenated isobutylene containing elastomer present in the air permeation prevention layer and the elastomer present in the tie layer, adhesive layer, and/or one or more carcass layers are the same elastomer. In another embodiment, they are different. By same is meant that the elastomers have comonomer and halogen content within 2 wt% of each other, respectively. By different is meant that the elastomers comprise different halogens or comonomers or that the elastomers have comonomer or halogen contents that are not within

2 wt% of each other. For example a BIMS copolymer having

3 wt% para-methyl styrene (PMS) and 5 wt% bromine is considered different from a BIMS copolymer having 11 wt% PMS and 5 wt% bromine. In a preferred embodiment, the elastomer present in the air permeation prevention layer is a brominated copolymer of isobutylene and para-methyl styrene and the halogenated isobutylene containing elastomer present in the tie layer, adhesive layer, and/or carcass is the same or a different brominated copolymer of isobutylene and para-methyl styrene. In another embodiment, the elastomer present in the air permeation prevention layer is a brominated copolymer of isobutylene and para-methyl styrene and the halogenated isobutylene containing elastomer present in the tie layer, adhesive layer, and/or one or more carcass layers is a brominated butyl rubber.

[0048] Useful compositions for purposes of the present invention also comprise blends of halogenated isobutylene-containing elastomers and blends comprising unhalogenated isobutylene-containing elastomers (i.e., in each instance in the present application the reference to "isobutylene-containing" referring to elastomers that have been synthesized using isobutylene as one of the monomers), such as butyl rubber blended with at least one halogenated isobutylene-containing copolymer, such as blends of halogenated copolymer of isobutylene and para- methylstyrene with halogenated butyl; halogenated butyl with unhalogenated butyl; blends of unhalogenated butyl with halogenated copolymer of isobutylene and para- methylstyrene; or other combinations, provided at least one halogenated elastome^ic random interpolymer, preferably comprising isobutylene, is included. Where unhalogenated isobutylene copolymer is included, such copolymer is typically present at a concentration of about 40 phr or less; preferably about 20 phr or less; for example, about 1 phr to about 20 phr; such as about 5 phr to about 15 phr.

[0049] The composition of the present invention employs at least one styreniσ block copolymer typically at concentrations greater than zero and less than about 20 parts per hundred of rubber (phr) ; preferably less than 10 phr; for example, about 1.0 to about 20 phr; alternatively, about 0.5 to about 10 wt% in a typical tire innerliner composition. The use of a styrenic block copolymer is beneficial in lowering the brittleness temperature of the composition. It can be used in combination with another rubber component that favorably reduces the brittleness temperature, for example, natural rubber, synthetic polyisoprene or mixtures thereof. When natural rubber is used in combination with a styrenic block copolymer the natural rubber concentration is typically used at concentrations that will have a positive affect on the brittleness temperature without significantly increasing the permeability of the composition. While the glass transition temperature of natural rubber is significantly lower than that of a halogenated isobutylene based elastomers it is also about 8 times more permeable than such elastomers, so that its concentration needs to be carefully controlled in compositions suitable for use as fluid or air barriers, e.g., tire innerliners and hoses. For example, acceptable air holding quality of a tire is typically about 3% per month or less under ambient conditions. Typically the amount is greater than zero and less than about 40 phr; preferably about 5 to about 35 phr,- more preferably about 10 to about 25 phr; for example, in amounts of about 20 phr or about 30 phr. The specific amount used can be adjusted depending on the other components in the composition, including the specific block copolymer and its impact on brittleness and permeability properties. Additionally, an organosilicate clay, particularly an exfoliated material, can also be used in combination with the polymers of the invention in, order to adjust or "balance" the brittleness and permeability properties based on the teachings of the present invention.

[0050] The styrenic block copolymer can be a dibloσk or triblock copolymer in which the middle block of the triblock or the second block of the dibloσk is derived from Ct to Cio conjugated diene monomer units, preferably butadiene or isoprene. The glass transition temperature of a butadiene block is typically about -90 ⁰C and that of an isoprene block is about -60 ⁰C. Consequently, butadiene is the preferred conjugated diene for the styrenic block copolymer. The preferred lead or end block for a triblock or diblock copolymer is styrenic, most preferably styrene. The presence of the styrene block (s) allows the block copolymer to be processed as a thermoplastic, typically a thermoplastic elastomer, which facilitates its compounding or mixing with the other rubber components and rubber compounding ingredients typically used in the compositions of the present invention. By controlling the styrene content of the block copolymer to be less than about 7011101%_/ preferably less than about 60 mol%, most preferably less than about 50 rnol%, the resulting block copolymer is soft, elastic and rubber-like, rather than hard, plastic and glass- like. The block copolymer also improves the compatibility between the halogenated isobutylene-based copolymer, in particular a brominated isobutylene-para- methylstyrene copolymer and the natural rubber or synthetic polyisoprene. Furthermore, the conjugated diene block of the block copolymer can be functionalized in order to further improve compatibility, dispersion and vulcanizability or co-cure with the matrix isobutylene- based rubber. Useful functionalization of the block copolymer includes carboxylation, malleation and epoxidation; epoxidized functionality is most preferred. [0051] The block copolymer of styrene derived monomer units and C₄ to Ci₀ conjugated diene derived monomer units useful in the present invention comprises a block copolymer or its partially hydrogenated product, the copolymer comprising a block of a vinyl aromatic compound and at least one block of a conjugated diene compound. Furthermore, the block copolymer can be at least partially hydrogenated and additionally it can be derivatized, for example, epoxidized. [0052] Useful styrene block copolymers include at least one C₄ to C₁Q conjugated diene derived monomer units in the block copolymer structure and the resulting unsaturated moieties can be at least partially hydrogenated and/or functionalized or derivatized. Examples of useful block copolymers include diblock and triblock copolymers of a styrene-isoprene-butadiene- styrene block copolymer (SIBS) ; a styrene-butadiene- styrene block copolymer (SBS); a styrene-ethylene- butylene-styrene block copolymer (SEBS) corresponding to the hydrogenated double bonded portion of the butadiene of the SBS structure, a styrene-isoprene-styrene block copolymer (SIS); a styrene-ethylene-propylene-styrene block copolymer (SEPS) corresponding to the hydrogenated double bonded portion of that isoprene of the SIS structure; a styrene- ethylene- ethylene-propylene- styrene block copolymer (SEEPS) ; and a modified or functionalized derivative of the above block copolymers and mixtures of the foregoing. [0053] In particular, useful amounts of styrene derived monomer units of the foregoing block copolymers (SIBS, SBS, SEBS, SIS, SEPS, and SEEPS) are typically about 10 to about 70 mol%; preferably about 15 to about 60 mol%; most preferably about 20 to about 50 mol% o£ the copolymer. The amount present is selected so that the block copolymer retains soft, elastic, rubber-like properties rather than hard, plastic, glass-like properties, particularly under conditions of use, [0054] The above block copolymers can be in modified or funσtionalized form, including carboxylated, maleated and epoxidized versions and mixtures thereof; epoxidized functionality is most preferred. Such functionality advantageously contributes to the compatibility of the various polymeric components that may be present, as well as enhancing dispersion and vulcanizability or co-cure with the matrix rubber component. Block copolymers useful in the present invention preferably include an epoxy group in the copolymer structures of the foregoing SIBS, SBS, SEBS, SIS, SEPS and SEEPS block copolymers. For example, suitable block copolymers include styrene- butadiene-styrene block copolymer (SBS) including a polybutadiene block with an epoxy group and wherein substantially all polymer chains have polystyrene blocks at both terminal positions of the polymer chain with an intermediate block of polybutadiene containing the epoxy group, and preferably wherein a portion or substantially all or all of the double bonds of the polybutadiene portion are hydrogenated. Alternatively, the block copolymer (such as a styrene-isoprene-styrene block copolymer) has a polyisoprene block containing an epoxy group and wherein substantially all polymer chains have polystyrene blocks at both terminal positions of the polymer chain with an intermediate block of polyisoprene containing the epoxy group, and preferably wherein a portion or substantially all or all of the double bond of the polyisoprene portion are hydrogenated. [0055] The amount of oxirane oxygen from the epoxy group present in the block copolymer of the epoxidized' block copolymer, preferably an SBS or SIS block copolymer, most preferably an SBS block copolymer, is typically about 0.05 to about 10 mol%; preferably about 0.1 to about 10 mol%; alternatively about 0.2 to about 5 mώl% and characterized as oxirane oxygen. The oxirane group is understood to be a subset of organic cyclic ether compounds wherein cyclic refers to the fact that the oxirane atoms, two carbons and an oxygen in a three membered ring, and ether indicating that there is a carbon-oxygen-carbon bonding arrangement. Such groups are commonly known as epoxides.

[0056] Methods for producing the block copolymers useful in the present invention, including expoxidized versions thereof, are known in the art. For example, a vinyl aromatic compound-conjugated diene compound block copolymers can be synthesized in an inert solvent using a lithium catalyst or the like by the methods described in JP 40-23798B, JP 51-33184A and others. Further, partially hydrogenated block copolymers, particularly useful for producing epoxidized block copolymers in the present invention can be synthesized by hydrogenation in an inert solvent in the presence of a hydrogenation catalyst by the method described in JP 42-8704B, JP 43- 6636B, or JP 59-133203A. The epoxidized diene block copolymer can be prepared by methods well-known in the art. For example, by reacting the above-mentioned block copolymers with epoxidizing agents such as hydroperoxides and peracids in an inert solvent. Examples of peracids include performic acid, peracetiσ acid, and perbenzoic acid. Where hydroperoxides are used a catalytic effect can be obtained by using hydrogen peroxide and a mixture of tungstic acid and sodium hydroxide, an organic acid and hydrogen peroxide, or .molybdenum hexacarbonyl and tertiary butyl hydroperoxide. [0057] Examples of epoxidized block copolymers of, for- example, SBS or SIS useful in the present invention are commercially available, and sold under the trade names. ^• "Epofriend" and "ESBS" from Daicel Chemical Industries Ltd., and hydrogenated, epoxidized SBS block copolymers sold under the trade name ESBS, also available from Daicel Chemical Industries Ltd. Particularly useful block copolymers include Epofriend AT501, Epofriend CT310, Epofriend A1005, Epofriend AlOlO and Epofriend A1020. Examples of maleated block copolymers of SEBS are Kraton FG series, such as FG1901 and FG1924 from Kraton Polymers. Examples of caboxylated SB copolymers are Rovene series, such as Rovene 9423, Rovene 5550, Rovene 4040, from Ameripol Synpol-Mallard Creek Polymers. [0058] Optionally, other rubbers or elastomers can be used in combination with the halogenated isobutylene- containing elastomer. Such an optional rubber component includes high diene rubbers and their hydrates. High diene content rubbers or elastomers are also referred to as high diene monomer rubber. It is typically a rubber comprising typically at least 50 mol% of a C₄ to C₁₂ diene monomer, typically at least about 60 mol% to about 100 mol%; more preferably at least about 70 mol% to about 100 mol%; more preferably at least about 80 mol% to a.bout 100mol%. Useful high diene monomer rubbers include horoopolymers and copolymers of olefins or isoolefins and multiolefins, or homopolymers of multiolefins. These are well known and are described in Rubber Technology, 179- 374 (Maurice Morton ed., Chapman & Hall 1995), and The Vanderbilt Rubber Handbook 22-80 (Robert F. Ohm ed,, R. T. Vanderbilt Co., Inc.^' 1990). Generally, other optional rubbers useful in the present invention include, for example natural rubber (NR) _r isoprene rubber (IR) , epoxylated natural rubber, styrene butadiene rubber (SBR) , polybutadiene rubber (BR) (including high cis BR and low cis BR) , nitrile butadiene rubber (NBR) , hydrogenated NBR, hydrogenated SBR, olefin rubbers (for example, ethylene propylene rubbers (including both EPDM and EPM) , maleic acid-modified ethylene propylene rubbers (M-EPM), butyl rubber (ΪIR) , isobutylene and aromatic vinyl or diene monomer copolymers, acrylic rubbers (ACM) , ionomers, other halogen-containing rubbers (for example, chloroprene rubbers (CR) , hydrin rubbers (CHR) , chlorosulfonated polyethylenes (CSM) , chlorinated polyethylenes (CM) , maleic acid-modified chlorinated polyethylenes (M-CM)), silicone rubbers (for example, methylvinyl silicone rubbers, dimethyl silicone rubbers, methylphenylvinyl silicone rubbers), sulfur-containing rubbers (for example, polysulfide rubbers), fluoro rubbers (for example, vinylidene fluoride rubbers, fluorine-containing vinyl ether-based rubbers, tetrafluoroethylene-propylene rubbers, fluorine- containing silicone rubbers, fluorine-containing phosphagen rubbers), thermoplastic elastomers (for example, styrene-containing elastomers, olefin elastomers, ester elastomers, urethane elastomers, or polyamide elastomers), and their mixtures, [0059] Preferred examples of high diene monomer rubbers include polyisoprene, polybutadiene rubber, styrene-butadiene rubber, natural rubber, chloroprene rubber, acrylonitrile-butadiene rubber and the like, which may be used alone or in combination and mixtures. Preferably, natural rubber is used, particularly in tire innerliner compositions in order to improve the low temperature performance of the composition. When used, the natural rubber typically is present at greater than 0 to about 30 wt%; typically about 5 phr to about 50 phr; preferably about 7 phr to about 40 phr; more preferably about 10 phr to about 30 phr.

[0060] With reference to the polymers and/or elastomers referred to herein, the terms "cured, " "vulcanized, " or "crosslinked" refer to the chemical reaction comprising forming bonds as, for example, during chain extension, or crosslinks between polymer chains comprising the polymer or elastomer to the extent that the elastomer undergoing such a process can provide the necessary functional properties resulting from the curing reaction when the tire is put to use. For purposes of the present invention, absolute completion of such curing reactions is not required for the elastomer-containing composition to be considered "cured, " "vulcanized" or "crosslinked. ", For example, for purposes of the present invention, a tire comprising an innerliner layer composition based on the present invention is sufficiently cured when the tire of which it is a component passes the necessary product specification tests during and after manufacturing and performs satisfactorily when used, on a vehicle. Furthermore, the composition is satisfactorily, sufficiently or substantially cured, vulcanized or crosslinked when the tire can be put to use even if additional curing time could produce additional crosslinks.

[0061] Generally, polymer compositions, e.g., those used to produce tires, innertubes, curing bladders and hoses, are crosslinked in the finished product. Crosslinking or vulcanization is accomplished by incorporation of curing agents and/or accelerators; the overall mixture of such agents being typically referred to as a cure "system." It is known that the physical properties, performance characteristics, and durability of vulcanized rubber compounds are directly related to the number (crosslink density) and types of crosslinks formed during the vulcanization reaction. {See, e.g., HeIt et al., The Post Vulcanization Stabilization for NR, RUBBER WORLD 18-23 (1991) . Curing agents include those components described above that facilitate or influence the cure of elastomers, and generally include metals, metal oxides, accelerators, sulfur, peroxides, and other agents common in the art, and as described above. Crosslinking or curing agents include at least one of, e.g., sulfur, zinc oxide, and fatty acids and mixtures thereof. Peroxide- containing cure systems may also be used. Generally, polymer compositions may be σrosslinked by adding curative agents, for example sulfur, metal oxides (i.e., zinc oxide, ZnO) , organometallic compounds, radical initiators, etc. and heating the composition or mixture. [0062] The following are common curatives that can function in the present invention: ZnO, CaO, MgO, AI₂O3, Crθ3, FeO, Fβ2θ₃, and NiO. These metal oxides can be used in conjunction with the corresponding metal stearate complex (e.g., the stearate salts of Zn, Ca, Mg, and Al), or with stearic acid, and either a sulfur compound or an alkylperoxide compound. (See also, Formulation Design and Curing Characteristics of NBR Mixes for Seals, ROBBER WORLD 25-30 (1993). To the curative agent (s) there are often added accelerators for the vulcanization of elastomer compositions. The curing agent (s), with or without the use of at least one accelerator, is often referred to in the art as a curing "system" for the elastomer(s) . A cure system is used because typically more than one curing agent is employed for beneficial effects, particularly where a mixture of high diene rubber and a less reactive elastomer is used. For example, in order to determine the cure response of the particular rubber (s) present in a composition, the rubber (s) and cure system can be combined by means known to those skilled in the art, e.g., on a two- roll mill, Banbury mixer or mixing extruder. A sample of the mixture, often referred to as the "accelerated" compound, can be cured under static conditions, such as in the form of a thin sheet using a mold that is subjected to heat and pressure in a press. Samples of the accelerated compound, cured as thin pads for progressively longer times and/or at higher temperatures, are then tested for stress strain properties and/or crosslink density to determine the state of cure (described in detail in American Society for Testing and Materials, Standard ASTM D412) . Alternatively, the accelerated compound can be tested for state of cure using an oscillating disc cure rheometer test (described in detail in American Society for Testing and Materials, Standard ASTM D2084) . The vulcanizable rubbers in the composition are sufficiently cured to achieve the desired properties of the composition of which they are a part, e.g., a fluid (air or liquid) retention barrier such a$ an innerliner for a tire. For purposes of the present invention, such state of cure can be referred to as "substantially fully cured." The specific state of cure is typically selected so as to obtain a balance of the desired properties of the composition for the application in which it is used, e.g., a tire innerliner, curing bladder, innertube, hose, etc. and particularly suitable for .the environment in which the article is used, e.g., ambient automobile conditions versus ambient aircraft conditions for an innertube or tire. Consequently, it may be desirable to control the state of cure of the rubber (s) used in the composition to be less than or equal to about 95% of the maximum degree of cure of which they are capable, as described above,

[0063] Suitable curative systems for the elastomeric halogenated copolymer component of the present invention include zinc oxide in combination, with zinc stearate or stearic acid and, optionally, one or more of the following accelerators or vulcanizing agents: Permalux {the di-ortho-tolylguanidine salt of dicatechol borate) ; HVA-2 (m-phenylene bis maleimide) ; Zisnet (2,4,6- trimercapto-5-triazine) ; ZDEDC (zinc diethyl dithiocarbamate) and also including for the purposes of the present invention, other dithiocarbamates; Tetrone A (dipentamethylene thiuram hexasulfide) ; Vultac 5 (alkylated phenol disulfide) ; SP1045 (phenol formaldehyde resin) ; SPl056 (brominated alkyl phenol formaldehyde resin) / DPPD (diphenyl phenylene diamine) ; salicylic acid, ortho-hydroxy benzoic acid; wood rosin, abietic acid; and TMTDS (tetramethyl thiuram disulfide), used in combination with sulfur. However, it will also be appreciated by one skilled in the art that it is also necessary to adjust the composition of the cure system, to achieve a balanced set of performance properties as described above. The methods by which this can be achieved are generally known to those skilled in this art and are further described in detail above, e . g. , by use of the method set forth in ASTM D2084 . tOO64] Curative accelerators include amines, guanidines, thioureas, thiazoles, thiurams, sulfenamides, sulfenimides, thiocarbamates, xanthates, and the like . Acceleration of the cure process may be accomplished by adding to the composition an amount of the accelerant . The ■ mechanism for accelerated vulcanization of rubber involves complex interactions between the curative, accelerator, activators and polymers. Ideally all of the available curative is consumed in the formation of effective crosslinks which join individual polymer chains to one another and enhance the overall strength of the polymer matrix. Numerous accelerators are known in the art and include, but are not limited to, the following: stearic acid, diphenyl guanidine (DPG) , tetramethylthiuram disulfide (TMTD) , 4, 4 ' -dithiodimorpholine (DTDM) , tetrabutylthiuram disulfide (TBTD) , 2,2 ' -benzothiazyl disulfide (MBTS) , hexamethylene-l, 6-bisthiosulfate disodium salt dihydrate, 2- (morpholinothio) benzothiazσle (MBS or MOR) , compositions of 90% MOR and 10% MBTS (MOR 90) , N- tertiarybutyl-2-benzothiazole sulfenamide (TBBS) , and N- oxydiethylene thiocarbamyl-N-oxydiethylene sulfonamide (OTOS) , zinc 2-ethyl hexanoate (ZEH) , N, N ' -diethyl thiourea. Curatives, accelerators and the cure systems of which they are a part that are useful with one or more crosslinkable polymers are well-known in the art . The cure system can be dispersed in a suitable concentration into the desired portion of the rubber component, the rubber component optionally containing one or more filler, extender and/or plasticizer by, e.g. , mixing the rubber and the cure system components using mixing equipment commonly used in the rubber industry for such purpose, e. g. , a two- roll rubber mill, a Banbury® mixer, a mixing extruder and the like. Such mixing is commonly referred to as "accelerating" the rubber composition. Alternatively, the rubber composition can be accelerated, in a stage of a mixing extruder. In one embodiment of the invention, at least one curing agent is typically present at about 0-1 to about 15 phr; alternatively at about 0.5 to about 10 phr, [0065] Useful combinations of curatives, cure modifiers and accelerators can be illustrated as follows: As a general rubber vulcanization agent, e.g., 'a suϊfur vulcanization agent, powdered sulfur, precipitated sulfur, high dispersion sulfur, surface-treated sulfur, insoluble sulfur, dimorpholinedisulfide, aljcylphenoldisulfide, and mixtures thereof are useful. Such compounds may be used in an amount of about 0.5 phr to about 4 phr (parts by weight per 100 parts by weight of the elastomer component) . Alternatively, where the use of such a material is feasible in view of other polymer and resin components present an organic peroxide vulcanization agent, benzoylperoxide, t- butylhydroperoxide, 2, 4-diσhlorobenzoylperoxide, 2,5- dimethyl-2,5-di(t-butylperoxy)hexane, 2_r 5-dimethylhexane- 2,5-di (peroxylbenzoate) , and mixtures thereof. When used, such curatives can be present at a level of about 1 phr to about 20 phr. Other useful curatives include phenol resin vulcanization agents such as a bromide of an alkylphenol resin or a mixed crosslinking agent system containing stannous chloride, chloroprene, or another halogen donor and an alkylphenol resin and mixtures thereof. Such agents can be used at a level of about 1 phr to about 20 phr. Alternatively, other useful curing agents, cure modifiers and useful levels include zinc oxide and/or zinc stearate (about 0.05 phr to about 5 phr), stearic acid (about 0.1 phr to about 5 phr), magnesium oxide (about 0.5 phr to about 4 phr),^' lyserge (10 to 20 phr or so), p-quinonedioxime, p- dibenzoylquinonedioxime, tetrachloro-p-ben∑oquinone, poly-p-dinitro≤obenzene (about 0,5 phr to about 10 phr) , methylenedianiline (about 0.05 phr to about 10 phr), and mixtures thereof. Further, if desired or necessary, one or more of a vulcanization accelerator may be added in combination with the vulcanization agent, including for example, an aldehyde-ammonia, guanidine, thiazole, sulfenamide, thiuram, dithio acid salt, thiurea, and mixtures thereof, for example, in an amounts of about 0.1 phr to about 5 phr or more.

[0066] One process for producing the elastomeric composition can be performed by the following procedure. First, a mixing device such as a Banbury mixer, two-roll rubber mill, etc. is used to pre-mix the elastomer component and predetermined amount of crosslinking agent (s) until a substantially uniform dispersion is obtained. Typically, the elastomer component (s) may already have added thereto suitable amounts of fillers and optional fillers such as carbon black or modified carbon black, clay or modified clay oil and/or plasticizer. It is preferable to add various compounding agents other than vulcanization agents to the composition in advance of dispersing the curing agents. During the phase of mixing during which the crosslinking agent (s) are dispersed the temperature has to be controlled at a low enough level for the particular elastomer (s) selected and in consideration of the activity of the cure system, in order to avoid premature crosslinking of the elastomers. A useful temperature during this mixing step can be less than about 120 ⁰C.

[0067] The composition described herein may also have one or more filler components such as calcium carbonate, clay, mica, silica and silicates, talc, titanium dioxide, starch and other organic fillers such as wood flour, and carbon black. Suitable filler materials include carbon black such as channel black, furnace black, thermal black, acetylene black, lamp black, modified carbon black such as silica treated or silica coated carbon black (described, for example, in U, S, Patent No, 5,916,934, incorporated herein by reference), and the like. Reinforcing grade carbon black is preferred. The filler may also include other reinforcing or non-reinforcing materials such as silica, clay, calcium carbonate, talc, titanium dioxide and the like. The filler raay be present at a level of from 0 to about 30 percent by weight of the rubber present in the composition.

[0068] Clays, including exfoliated, intercalated, or dispersed clays may also be present in the composition. The latter clays, also referred to as "nanoclays", are well known, and their identity, methods of preparation and blending with polymers is disclosed in, for example, JP 2000109635, JP 2000109605, JP 11310643; DE 19726278; WO98/53000; and U.S. Patent Nos. 5,091,462, 4,431,755, 4,472,538, and 5,910,523. Swellable layered clay materials suitable for the purposes of the present invention include natural or synthetic phyllosilicates, particularly smβctic clays such as montmorillonite, nontronite, beidellite, volkonskoite, laponite, hectorite, saponite, sauconite, magadite, kenyaite, stevensite and the like, as well as vermiculite, halloysite, aluminate oxides, hydrotalcite and the like. These layered clays generally comprise particles containing a. plurality of silicate platelets having a thickness typically about 4 to about 2θA in one embodiment, and about 8 to about 12A in another embodiment, bound together and containing exchangeable cations such as Na⁺, Ca⁺², K⁺ or Mg⁺² present at the interlayer surfaces.

[0069] Layered clay may be intercalated and exfoliated by treatment with organic molecules (swelling agents) capable of undergoing ion exchange reactions with the cations present at the interlayer surfaces of the layered silicate. Suitable swelling agents include cationic surfactants such as ammonium, alkylamines or alkylairanonium (primary, secondary, tertiary and quaternary) , phosphonium or sulfønium derivatives of aliphatic aromatic or arylaliphatic amines, phosphines and sulfides. Desirable amine compounds (or the corresponding ammonium ion) are those with the structure R₁R₂R3N, wherein Ri, R2, and R3 are Ci to C3₀ alkyls or alken.es which may be the same or different. In one embodiment, the exfoliating agent is a so-called long chain tertiary amine, wherein at least R₁ is a C₁₂ to C₂₀ alkyl or alkene.

[0070] Another class of swelling agents includes those which can be covalently bonded to the interlayer surfaces. These include polysilanes of the structure - Si{R')₂R² where R¹ is the same or different at each occurrence and is selected from alkyl, alkoxy or oxysilane and R² is an organic radical compatible with the matrix polymer of the composite. Other suitable swelling agents include protonated amino acids and salts thereof containing 2-30 carbon atoms such as 12-aminododecanoic acid, epsilon-caprolactam and like materials. Suitable swelling agents and processes for intercalating layered silicates are disclosed in U.S. Pat. Nos. 4,472,538; 4,810,734; 4,889,885; and WO 92/02582. [0071] In another embodiment of the invention, the exfoliating or swelling agent is combined with a halogenated polymer. In one embodiment, the agent includes all primary, secondary and tertiary amines and phosphines; alkyl and aryl sulfides and thiols; and their polyfunσtional versions. Desirable additives include: long-chain tertiary amines such as N,N-dimethyl- octadecylamine, N,N-dioctadeσyl-raethylamine, dihydrogenated tallowalkyl-methylamine and the like, and amine-terminated polytetrahydrofuran; long-chain thiol and thiosulfate compounds such as hexamethylene sodium thiosulfate. in another embodiment of the invention, improved interpolyrner impermeability is achieved by the use of polyfunctional curatives such as hexamethylene bis (sodium thiosulfate) and hexamethylene bis (cinnamaldehyde) .

[0072] The amount of exfoliated, intercalated, or dispersed clay incorporated in the composition in accordance with this invention is an amount sufficient to develop an improvement in the mechanical properties and/or barrier properties of the composition, e.g. tensile strength or air/oxygen permeability. Amounts typically can be from about 0.5 to about 15 wt% in one embodiment, or about 1 to about 10 wt% in another embodiment, and about 1 to about 5 wt% in yet another embodiment, based on the polymer content of the composition. Expressed in parts per hundred rubber, the exfoliated, intercalated, or dispersed clay may be present at about 1 to about 30 phr in one embodiment, and about 3 to about 20 phr in another embodiment. In one embodiment, the exfoliating clay is an alkylamine- exfoliating clay.

[0073] As used herein, the term "process oil" means both the petroleum derived process oils and synthetic plasticizers. A process or plasticizer oil may be present in air barrier compositions. Such oils are primarily used to improve the processing of the composition during preparation of the layer, e.g., mixing, calendering, etc., but the amount used needs to be limited as their presence in the composition typically increases the permeability of fluids through the composition; for example, increase air permeability of innerliner and innertube compositions. Suitable plasticizer oils can include aliphatic acid esters or hydrocarbon plasticizer oils such as paraffiniσ or naphthenic petroleum oils. The preferred plasticizer oil for use in standard, non-DVA, non-engineering resin- containing innerliner compositions is a paraffinic or naphthenic petroleum oil. Suitable hydrocarbon plasticizer oils for use in such innerliners include oils having the following general characteristics.

[0074] Generally, the process oil may be selected from paraffinic oils, aromatic oils, naphthenic oils, and polybutene oils. Polybutene process oil is a low molecular weight (less « than 15,000 Mn) homopolymer or copolymer of olefin-derived units having from about 3 to about 8 carbon atoms, more preferably about 4 to about 6 carbon atoms. In another embodiment, the polybutene oil is a homopolymer or copolymer of a Cj raffinate- Low molecular weight "polybutene" polymers are described in, for example, SYNTHEUC LUBRICANTS AND HIGH-PERFORMANCE FUNCTIONAL FLUIDS 357-392 (Leslie R. Rudnick & Ronald L. Shubkin, ed., Marcel Dekker 1999) (hereinafter "polybutene processing oil" or "polybutene") . Useful examples of polybutene oils are the PARAPOL™ series of processing oils (previously available form ExxonMobil Chemical Company, Houston TX, now available from Infineum International Limited, Milton Hill, England under the "INFINEUM c, d, f or g trade name), including grades previously identified as PARAPOL™ 450, 700, 950, 1300, 2400, and 2500. Additionally preferred polybutene oils are SUNTEX™ polybutene oils available from Sun Chemicals. Preferred polybutene processing oils are typically synthetic liquid polybutenes having a certain number average molecular weight, Mn, preferably from about 420 to about 2700. The molecular weight distribution, weight average molecular weight, Mw, to number average molecular weight, Mn, Mw/Mn, (¹¹MWD") of preferred polybutene oils is typically about from 1,8 to about 3, preferably about 2 to about 2.8. The preferred density (g/ml) of useful polybutene processing oils varies from about 0.85 to about 0.91. The bromine number (CG/G) for preferred . polybutene oils ranges from about 40 for 450 Mn process oil, to about 8 for 2700 Mn process oil. [0075] Rubber process oils also have ASTM designations depending on whether they fall into the class of paraffiniσ, naphthenic or aromatic hydroσarbonaceous process oils. The type of process oil utilized will be that customarily used in conjunction with the major type of elastomer component present in the composition or one that is suitably compatible with the polymer components present and a rubber chemist of ordinary skill in the art will recognise which type of oil should be utilized with a particular rubber, rubber mixture or polymer mixture in a particular application. For innerliner compositions the oil is typically present at a level, of 0 to about 25 wt %; preferably about 5 to 20 wt % of the total composition. For innertube compositions oil may be present at levels typically at about 5 phr to about 30 phr; preferably about 10 phr to about 25 phr. For a thermoplastic elastomer composition the oil may be present at a level of 0 to about 20 wt % of the total composition/ preferably oil is not included or is minimized in order to maximize impermeability of the composition.

[00763 In addition, plasticizers such as organic esters and other synthetic plasticizers may be used. In another embodiment, rubber process oils such as naphthenic, aromatic or paraffinic extender oils may be present at about 1 to about 5 parts per hundred of rubber, phr. In still another embodiment, naphthenic, aliphatic, paraffinic and other aromatic oils are substantially absent from the composition. By "substantially absent", it is meant that naphthenic, aliphatic, paraffinic and other aromatic oils may be present, if at all, to an extent no greater than 2 phr in the composition. [0077] The elastomer compositions of the present invention can be formed into a sheet, film, or tube using, e.g., an extruder or calender in order to construct an air permeation preventive layer, e.g,, an innerliner of a pneumatic tire or tire curing bladder, an innertube, and as a component or layer of a hose, etc. Furthermore, the low permeability characteristics of the composition are suitable for uses with fluids other than gasses, e.g., liquids such as water, hydraulic fluid, brake fluid, heat transfer fluid, etc., provided that the layer in direct contact with the fluid has suitable resistance to the fluid being handled. [0078] Any range of numbers recited in the specification hereinabove or in the claims hereinafter, referring to various aspects of the invention, such as that representing a particular set of properties, units of measure, conditions, physical states or percentages, is intended to literally incorporate expressly herein by reference or otherwise, any number falling within such range, including any subset of numbers or ranges subsumed within any range so recited. Furthermore, the term "about" when used as a modifier for, or in conjunction with, a variable, characteristic or condition is intended to convey that the numbers, ranges, characteristics and conditions disclosed herein are flexible and that practice of the present invention by those skilled in the art using temperatures, times, concentrations, amounts, contents, carbon numbers, properties such as particle size, surface area, bulk density, etc., that are outside of the range or different from a single value, will achieve the desired result, namely, an dynamically vulcanized, high elastomer-content composition comprising at least one isobutylene-containing elastomer and at least one thermoplastic suitable for use, for example, in a pneumatic tire or hose, or as a tire innerliner. [0079] Throughout the entire specification, including the claims, the word "comprise" and variations of the word, such as "comprising" and "comprises," as well as "have," "having/¹ "includes/" "include" and "including," and variations thereof, means that the named steps, elements or materials to which it refers are essential, but other steps, elements or materials may be added and still form a construct within the scope of the claim or disclosure. When recited in describing the invention and in a claim, it means that the invention and what is claimed is considered to be what follows and potentially more. These terms, particularly when applied to claims, are inclusive or open-ended and do not exclude additional, unrecited elements or methods steps. [0080] For purposes of the present invention the phrase "consisting essentially of" is meant to exclude any component or combination of components or, as appropriate, any amount of any component or combination of components that would alter the basic and novel characteristics of the invention. Thus a particular component or mixture of components that would increase the brittleness temperature of the resulting cured composition to a level that is unsatisfactory for its intended use would be excluded. For example, and again for exemplary purposes only, an amount of natural rubber that may be useful for its beneficial contribution to low temperature properties, if present at too high a level may undesirably raise the permeability characteristics of the cured composition in the specific application of interest and thus such a .level would be undesirable. Alternately this invention relates to:

1. A fluid barrier composition prepared from a mixture comprising:

(A) about 30 to about 80 weight percent of at least one halogenated elastomeriσ random interpolymer comprising at least about 80 wt% of a polymerized isomonoolefin containing from 4 to 12 carbon atoms and about 0,5 to about 20 wt% of monomer units of (a) at least one C₄ to Ci₄ multiolefin; or (b) at least one para- alkylstyrene; or (c) a mixture of at least one of (a) and at least one of (b) /

(B) about 0.5 to about 20 wt% of at least one block copolymer of styrene derived monomer units and Cj to Cio conjugated diene derived monomer units;

(C) about 20 to about 45 wt % of a filler,

(D) greater than 0 to about 25 wt % of a plastiσizer oil; and

(E) about 1 to about 10 wt% of a curing system for said interpolyiner.

2. The composition of paragraph 1 wherein said at least one block copolymer is selected from a dibloσk copolymer or a triblock copolymer wherein the second block of the diblock or the middle block of said triblock is derived from C^ to Ci₀ conjugated diene monomer units.

3, The composition of paragraph 1 or 2 wherein said at least one block copolymer is selected from the group consisting of hydrogenated, non-hydrogenated_f functionalized and non-funσtionalized block copolymers.

4.. The composition of paragraph 1, 2 or 3 wherein said at least one block copolymer is an epoxidized styrene-butadiene-styrene block copolymer including an oxirane oxygen group.

5. The composition of paragraph 1, 2, 3 or 4 wherein said at least one block copolymer comprises about 40 to about 70 mol% styrene and about 0.05 to about 10 mol% oxirane oxygen.

6. The composition of paragraph 1, 2, 3, 4, or 5 further comprising greater than 0 to about 30 wt% of a polymer selected from the group consisting of natural rubber, polyisoprene and polybutadiene rubber.

7. The composition of any of paragraphs 1 to 6 further comprising about 0.5 to about 10 wt% of an organosilicate,

8. The composition of paragraph 7 wherein said organosiliσate is at least partially exfoliated.

$ . The composition of any of paragraphs 1 to 8 wherein said isomonoolefin is isobutylene, said para- alkylstyrene is para-methylstyrene and said halogen is bromine.

10. The composition of any of paragraphs 1 to 8 wherein said isomonoolefin is isobutylene, said iuultiolefin is isoprene and said halogen is bromine.

11. The composition of any of paragraphs 1 to 8 wherein said isomonoolefin is isobutylene, said para- alkylstyrene is para-methylstyrene,. said πmltiolefin is isoprene and said halogen is bromine.

12. The composition of any of paragraphs 1 to 11 wherein said filler is reinforcing grade carbon black,

13. The composition of any of paragraphs 1 to 12 comprising about 3 to about 10 wt% of said plasticizer oil.

14. The composition of any of paragraphs 1 to 13 wherein said curing system comprises accelerated sulfur curing agents.

15. The composition of any of paragraphs 1 to 14 further comprising an unhalogenated isobutylene- containing elastomer.

16. The composition of any of paragraphs 1 to 15 wherein said fluid barrier is employed in an article selected from the group consisting of motor vehicle innerliners, aircraft tire innerliners, motor vehicle tire innertubes_f aircraft tire innertubes, tire curing bladders and hoses,

17. A fluid barrier composition prepared from a mixture comprising;

(A) about 30 to about 80 weight percent of at least one halogenated elastorneric random interpolymer comprising at least about 80 wt% of a isobutylene and about 0.5 to about 20 wt% of monomer units of (a) isoprene; or (b) para- methylstyrene; or (c) a mixture of at least one of (a) and at least one of (b) ; and wherein said halogen is bromine;

(B) about 0,5 to about 20 wt% of at least one block copolymer of epoxidized styrene-butadiene- styrene block copolymer, said copolymer comprising about 40 to about 70 mol% styrene and about 0.05 to about 10 mol% oxirane oxygen;

(C) about 20 to about 45 wt % of a reinforcing carbon black, '

(D) about 3 to about 10 wt % of a plastiσizer oil;

(E) greater than 0 to less than about 30 wt% of natural rubber;

(F) about 0.5 to about 10 wt% of an at least partially exfoliated organosilicate; and

(G) about 1 to about 10 wt% of a curing system for said interpolymer.

18. A pneumatic tire comprising at least one each of an outer tread and sidewall portion, an inner carcass portion adhered to said tread sidewall portion and an innerliner sheet adhered to the inner surface of said carcass portion, said innerliner comprising the composition of any of paragraphs 1 to 17.

19. Α. vulcanized composition prepared by heating the composition of any of paragraphs 1 to 18 at a temperature of from about 100⁰C to about 250 "C for a period of time sufficient to vulcanize said composition.

20. A vulcanized pneumatic tire prepared by heating the tire structure of claim 18 at a temperature of from about 100⁰C to about 250⁰C for a period of time sufficient to vulcanize said tire.

21. The pneumatic tire of claim 18 selected from the group consisting of automobile, truck, bus, construction vehicle, off-road vehicle, military vehicle, motor vehicle and aircraft tires.

22. A process for fabricating a pneumatic tire comprised of at least one carcass element comprising at least one unsaturated rubber and at least one innerliner element adhered to said at least one carcass element comprising:

(A) forming into an innerliner sheet a composition comprising a mixture of:

(a) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a polymerized isomonoolefin containing from 4 to 12 carbon atoms and about 0.5 to about 20 wt% of monomer units of (i) at least one C₄ to C^ multiolefin; or (ii) at least one para-alkylstyrene; or (iii) a mixture of at least one of (i) and at least one of (ii);

(b) about 0.5 to about 20 wt% of at least one block copolymer of styrene derived monomer units and C₄ to Ci₀ conjugated diene derived monomer units;

(c) greater than 0 to about 30 wt% of a polymer selected from the group consisting of natural rubber, polyisoprene and

■ polybutadiene rubber;

(d) about 20 to about 45 wt % of at least one filler,

(e) greater than 0 to about 25 wt % of a plastiσizer oil; and

(f) at least 1 wt % of a curing system for said interpolymer;

(B) contacting said innerliner sheet material with said at least one tire carcass element to form a laminated structure; and

(C) heating said structure at a temperature of from about 100 ⁰C to about 250⁰C for a period of time sufficient to vulcanize said structure.

23. A fluid barrier composition prepared from a mixture comprising: {A) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a isobutylene and about 0.5 to about 20 wt% of monomer units of (a) isoprene; or (b) para- methylstyrene; or (c) a mixture of isoprene and para-methylstyrene and wherein said halogen is bromine;

(B) about 0.5 to about 20 wt% of at least one block copolymer of epoxidized styrene-butadiene- styrene block copolymer, said copolymer comprising about 40 to about 70 mol% styrene and about 0.05 to about 10 mol% oxirane oxygen;

(C) about 20 to about 45 wt % of a reinforcing carbon black,

(D) about 3 to about 10 wt % of a plasticizer oil;

(E) greater than 0 to less than about 30 wt% of natural rubber;

(G) about 1 to about 10 wt% of a curing system for said interpolymer.

EXAMPLES

[0081] The following commercially available products were used for the components employed in the Examples

[0082] Properties of the compounds prepared in the following table include:

Mooney: Composition Mooney viscosity at 100 ⁰C, value read at (1+4) ASTM D1646

Scorch: Mooney scorch at 135 ⁰C, time to a 5 point rise

(t5) ASTM D2084 t90: Cure time to achieve 90% of maximum cure at

160 ⁰C, minutes ASTM D2084

Shore: Shore A hardness, ASTM D2240

E: 100% modulus, MPa, ASTM D412-92

Tensile: Tensile strength, MPa, ASTM D412-92

Elong: Elongation at break, %, ASTIM D412-92

Perm: Oxygen permeability at 60 ^PC, Mocon test, not an

ASTM test

Brittle: Brittleness temperature, ⁰C, ASTM D746-Q4

[0083] In accordance with the formulations or compositions listed in Tables 1 and 2, in which compositions_, are expressed as parts per hundred of rubber or phr (unless otherwise noted) , a typical mixing procedure for preparing the compositions is as follows; BIIR or BIMS and NR are first blended in a size BR Banbury® internal mixer at 40 rpm, 40 psi and using temperature control set to 35 ⁰C. After 30 seconds, the carbon black is added, and after the temperature reaches 100 ⁰C, the oils and other components are added. All of the components are blended until the temperature reaches 125 "C. The blended or mixed composition is "finalized" by mixing and dispersing the curatives and AT-501 on a two-roll rubber mill.

[0084] In the following tables, examples 1, 3, 5, 7, and 9 are comparative examples without AT-501. Various rubber components were studied in the examples, as follows: examples 1 and 2 use 100 phr BIIR; examples 3 and 4 use 80/20 phr BIIR/NR; examples 5 and 6 use 100 phr BIMS; examples 7 and 6 use 80/20 phr BIMS/NR; and examples 9-13 use 70/30 phr BIMS/NR. MgO is used in the BIIR compositions to prevent degradation and to control scorch whereas stearic acid is added first in BIIR compounds to assist processing, As shown in Table 1, addition of AT-501 lowers the brittleness temperature, especially for blends containing NR. There is no measurable effect of AT-501 on brittleness temperature of a 100 phr BIIR compound with the test employed. Effects of AT-501 on other properties are minor, most notably are increases in hardness, modulus, and scorch time and a slight reduction in elongation at break. [0085] Table 1

AT-501 is not a curative, but is added with the curatives and dispersed into the mixture

[0086] Table 2

* AT-501 is not a curative, but is added with the curatives and dispersed into the mixture [0087] All documents described herein are incorporated by reference herein, including any priority documents and/or testing procedures to the extent they are not inconsistent with this text. The principles, preferred embodiments, and modes of operation of the present invention have been described in the foregoing specification. Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. Α fluid barrier composition prepared from a. mixture comprising!

(A) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a polymerized isomonoolefin containing from 4 to 12 carbon atoms and about 0,5 to about 20 wt% of monomer units of (a) at least one C4 to C₁₄ multiolefin; or (b) at least one para- alkylstyrene/ or (σ) a mixture of at least one of (a) and at least one of (b) ;

(B) about 0.5 to about 20 wt% of at least one block copolymer of styrene derived monomer units and C₄ to Cio conjugated diefle derived monomer units;

(C) about 20 to about 45 wt % of a filler,

(D) greater than 0 to about 25 wt % of a plasticizer oil; and

(E) about 1 to about 10 wt% of a curing system for said interpolymer.

2. The composition of claim 1 wherein said at least one block copolymer is selected from a dibloσk copolymer or a triblock copolymer wherein the second block of the diblock or the middle block of said triblock is derived from C₄ to C₁₀ conjugated diene monomer units.

3. The composition of claim 2 wherein said at least one block copolymer is selected from the group consisting of hydrogenated, non-hydrogenated_r functionalized and no_.n-functionalized block copolymers.

4. The composition of claim 3 wherein said at least one block copolymer is an epoxidized styrene- butadiene-styrene block copolymer including an oxirane oxygen group.

5. The composition of claim 4 wherein said at least one block copolymer comprises about 40 to about 70 mol% styrene and about 0.05. to about 10 mol% oxirane oxygen.

6. The composition of claim 1 further comprising greater than 0 to about 30 wt% of a polymer selected from the group consisting of natural rubber, polyisoprene and polybutadiene rubber.

7. The composition of claim 1 further comprising about 0.5 to about 10 wt% of an organosilicate.

8. The composition of claim 7 wherein said organosilicate is at least partially exfoliated.

9. The composition of claim 5 wherein said isomonoolefin is isobutylene, said para-alkylstyrene is para-methylstyrene and said halogen is bromine.

10. The composition of claim 5 wherein said isomonoolefin is isobutylene, said multiolefin, is isoprene and said halogen is bromine.

11. The composition of claim 5 wherein said isomonoolefin is isobutylene, said para-alkylstyrene is para-methylstyrene_r said multiolefin is isoprene and said halogen is bromine.

12. The composition of claim 1 wherein said filler is reinforcing grade carbon black.

13. The composition of claim 1 comprising about 3 to about 10 wt% of said plasticizer oil.

14. The composition of claim 1 wherein said curing system comprises accelerated sulfur curing agents.

15. The composition of claim 1 further comprising an unhalogenated isobutylene-containing elastomer.

16. The composition of claim 1 wherein said fluid barrier is employed in an article selected from the group consisting of motor vehicle tire innerliners, aircraft tire innerliners, motor vehicle tire innertubes, aircraft tire innertubes, tire curing bladders and hoses.

17. A fluid barrier composition prepared from a mixture comprising:

(A) about 30 to about 80 weight percent of at least one halogenated elastomeriσ random interpolymer comprising at least about 80 wt% of a isobutylene and about 0,5 to about 20 wt% of monomer units of (a) isoprene; or (b) para-methylstyreπe; or (c) a mixture of at least one of (a) and at least one of (b) ; and wherein said halogen is bromine;

(B) about 0.5 to about 20 wt% of at least one block copolymer of epoxidized styrene-butadiene-styrene block copolymer, said copolymer comprising about 40 to about 70 mσl% styrene and about 0.05 to about 10 mol% oxirane oxygen;

(C) about 20 to about 45 wt % of a reinforcing carbon black,

(D) about 3 to about 10 wt % of a plasticizer oil;

(E) greater than 0 to less than about 30 wt% of natural rubber;

(G) about 1 to about 10 wt% of a curing system for said interpolymer .

18. A pneumatic tire comprising at least one each of an outer tread and sidewall portion, an inner carcass portion adhered to said tread sidewall portion and an innerliner sheet adhered to the inner surface of said carcass portion, said innerliner comprising the composition of claim 1.

19. A vulcanized composition prepared by heating the composition of claim 1 at a temperature of from about 100 ⁰C to about 250 ⁰C for a period of time sufficient to vulcanize said composition.

20. A vulcanized pneumatic tire prepared by heating the tire structure of claim 18 at a temperature of from about 100 ⁰C to about 250 ⁰C for a period of time sufficient to vulcanize said tire.

21. The pneumatic tire of claim 18 selected from the group consisting of automobile, truck, bus, construction vehicle/ off-road vehicle, military vehicle, motor vehicle and aircraft tires.

(A) forming into an innerliner sheet a composition comprising a mixture of:

(a) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a polymerized isomonoolefin containing from 4 to 12 carbon atoms and about 0.5 to about 20 wt% of monomer units of (i) at least one C₄ to C₁₄ multiolefin; or (ii) at least one para-alkylstyrene; or (iii) a mixture of at least one of (i) and at least one of (ii);

(b) about 0.5 to about 20 wt% of at least one block copolymer of styrene derived monomer units and C₄ to Cio conjugated diene derived monomer units;

(σ) greater than 0 to about 30 wt% of a polymer selected from the group consisting of natural rubber, polyisoprene and polybutadiene rubber;

(d) about 20 to about 45 wt % of at least one filler,

(e) greater than 0 to about 25 wt % of a plasticizer oil; and

(f) at least 1 wt % of a curing system for said interpolymer;

(C) heating said structure at a temperature of from about 100 ⁰C to about 250 ⁰C for a period of time sufficient to vulcanize said structure.

23, A fluid barrier composition prepared from a mixture comprising:

(A) about 30 to about 80 weight percent of at least one halogenated elastomeric random interpolymer comprising at least about 80 wt% of a isobutylene and about 0.5 to about 20 wt% of monomer units of (a) isoprene; or (b) para-methylstyrene; or (c) a mixture of isoprene and para-methylstyrene and wherein said halogen is bromine;

(B) about 0.5 to about 20 wt% of at least one block copolymer of epoxidized styrene-butadiene-styrene block copolymer, said copolymer comprising about 40 to about 70 mol% styrene and about 0,05 to about 10 mol% oxirane oxygen;

(C) about 20 to about 45 wt % of a reinforcing carbon black,

(D) about 3 to about 10 wt % of a plasticizer oil;

(E) greater than 0 to less than about 30 wt% of natural rubber;

(F) about 0.5 to about 10 wt% of an at least, partially exfoliated organosilicate; and

(G) about 1 to about .10 wt% of a curing system for said interpolymer.