WO2007111584A1

WO2007111584A1 - Thermoplastic elastomer composition having excellent low temperature property

Info

Publication number: WO2007111584A1
Application number: PCT/US2006/011002
Authority: WO
Inventors: Yoshihiro Soeda; Andy Haishung Tsou; Yuichi Hara; Matthew Brian Measmer
Original assignee: The Yokohama Rubber Co., Ltd.; Exxonmobil Chemical Patents Inc.
Priority date: 2006-03-24
Filing date: 2006-03-24
Publication date: 2007-10-04

Abstract

A thermoplastic elastomer composition a thermoplastic elastomer composed of at least partially , vulcanized first rubber component discretely dispersed in a polyamide matrix and a secondary rubber component, which is different from the first rubber component, having a glass transition temperature Tg of -30°C or less.

Description

- 1 -

THERMOPLASTIC ELASTOMER COMPOSITION HAVING EXCELLENT LOW TEMPERATURE PROPERTY

5 Technical Field

The present invention relates to an improved thermoplastic elastomer composition and blend having excellent heat resistance, durability and. flexibility, while possessing superior air impermeability for

10 applications in a tire innerliner and barrier film. In particular, the present invention relates to a soft thermoplastic elastomer composition having excellent flexibility at a low temperature utilizing a finely dispersed softener. Most specifically, the present

15 invention relates to a thermoplastic elastomer composition containing 1 to 20 weight % of a reactive compatibilizable softener having a dispersion size of 1 μm or less.

20 Background of the Invention

EP 722850B1 disclosed a low-permeability thermoplastic elastomer composition that is superior as a gas-barrier layer in a pneumatic tire. This

25 thermoplastic elastomer composition comprises a low- permeability thermoplastic matrix such as a polyamide, a blend of a polyamide or a copolymer of a polyamide, in which a low-permeability rubber such a≤ brominated poly(isobutylene-co-paramethylstyrene) (i.e., BIMS), is

30 dispersed. Subsequently, in both EP 857761A1 and

EP 969039A1, a viscosity ratio between the thermoplastic matrix and the rubber dispersion was specified both as a function of the volume fraction ratio and independently . to be close to one in order to, achieve phase continuity

35 in a thermoplastic and fine rubber dispersion, respectively. Criticality of a smaller rubber dispersion was recognized in EP 969039A1 in these thermoplastic 2

elastomers for delivering acceptable durability,, especially for their usage as an innerliner in a pneumatic tire.

For these low-permeability thermoplastic elastomers 5 based on a vulcanized blend of a polyamide and BIMS to be used as an innerliner in a tire, it is preferable to have a low modulus at a low temperature. Kn innerliner is commonly laminated to a soft elastomer compound such as a tie compound (or a squeeze compound) or a carcass

10 compound, with a modulus a ranging from 0.1 to 20 MPa. Α high modulus innerliner could have undesirable internal stress build up during cyclic loading of a tire due to its modulus mismatch leading to premature failure. This is especially emphasized in the thermoplastic elastomeric

15 innerliner based on a blend of a polyamide and a brominated copolymer of isobutylene and paramethylstyrene (BIMS) at a low temperature preferably having a low modulus and a-fine dispersion in a polyamide resulting from its reactive compatibilization with polyamides.

20 Although BIMS typically have a Tg at -60⁰C, their modulus starts to rise when a temperature is lowered below O⁰C. This unique earlier modulus rise before an ambient temperature approaching Tg is the result of the rather unique broad glass transition in an isobutylene-based

25 elastomer, such as brominated copolymers of isobutylene and paramethylstyrene. Considering that a tire is used at a place where an average winter temperature is down to -20⁰C, it is desirable to have a thermoplastic elastomeric innerliner that also has a low modulus

30 at -20⁰C.

One method to lower the low temperature modulus of a polyamide/BΪMS thermoplastic elastomer is to increase the BIMS rubber content. Although BIMS is slightly stiffened at -2O⁰C, it is still significantly softer than the

35 polyamide thermoplastic matrix. According to the criterion of phase continuity, lowering the viscosity of 3

polyamide or raising the viscosity of BIMS is required to maintain polyamide as the continuous phase, while raising the BIMS content. Although overall softening of the resulting thermoplastic elastomer can be accomplished 5 with an increasing BIMS rubber content, enlargement of the dispersion is unavoidable with the increase rubber collision frequency during mixing. The enlargement of rubber dispersion discourages the formation of trans- crystallinity in a polyamide leading to the erosion of 10 their fatigue resistance.

Other references of interest include, for example, WO 2004/081107, WO 2004/081106, WO 2004/081108, WO 2004/081116, and WO 2004/081099.

15 Summary of the Invention

The object of the present invention is to provide a thermoplastic elastomer composition or a blend for a tire innerliner and barrier film having an excellent

20 durability, impermeability, low temperature flexibility and fatigue resistance.

This invention relates to a thermoplastic elastomer composition or a blend comprising a thermoplastic elastomer composed of at least partially vulcanized first

25 rubber component discretely dispersed in a polyamide matrix and a second polymer component (which may also be partially or completely vulcanized) , which is different from the first rubber component, and has a glass transition temperature Tg of -2O⁰C or less {preferably -30

30 ⁰C or less) .

Thus, in accordance with the present invention, there is provided a thermoplastic elastomer composition comprising a thermoplastic elastomer composed of at least partially vulcanized first rubber component discretely

35 dispersed in a polyamide matrix and a secondary rubber component (which may also be partially or completely vulcanized) , which is different from the first rubber 4

component, having a glass transition temperature Tg of -30"C or less.

In accordance with the present invention, there is also provided a blend comprising a first rubber component 5 at least partially vulcanized dispersed as particles having a size of 1 micron or less in a polyamide matrix; and a second polymer component different from the first rubber component, where the second polymer component has a Tg spread of less than 20 ⁰C as measured by DMTA run at

10 10 ⁰C per minute at 1 hertz, a Tg of -20 ⁰C or less, a weight average molecular weight greater than 20,000 and comprises at least 0.1 to 25% by weight of a functional group, based upon the total weight of the second polymer component .

15 The present invention is directed to use one or more reactive softeners in a thermoplastic elastomer composition based on a polyamide and halogenated copolymer of a Cs to C₇ isoolefin and a para-alkylstyrene at a concentration of 20% by weight or less, based upon

20 the total weight of the polyamide and halogenated copolymer, and a dispersion size of 1 μm or less.

Detailed Description of the Invention

25 In this specification and in the claims which follow, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

Polymer may be used to refer to homopolymers, 30 copolymers, interpolymers, terpolymers, etc. Likewise, a copolymer may refer to a polymer comprising at least two monomers, optionally with other monomers.

When a polymer is referred to as comprising a monomer, the monomer is present in the polymer in the 35 polymerized form of the monomer or in the derivative form the monomer. However, for ease of reference the phrase 5

"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 skilled in the 5 art, that the active form of the component is the form that reacts with the monomers to produce polymers.

Isoolefin refers to any olefin monomer having two substitutions on the same carbon.

Multiolefin refers to any monomer having two double

10 bonds. In a preferred embodiment, the multiolefin is any monomer comprising two double bonds, preferably two conjugated double bonds such as a conjugated diene like isoprene.

Elastomer or elastomers as used herein, refers to

15 any polymer or composition of polymers consistent with the ASTM D1566 definition. The terms may be used interchangeably with the term "rubber (s)."

Alkyl refers to a paraffinic hydrocarbon group which may be derived from an alkane by dropping one or more

20 hydrogens from the formula, such as, for example, a methyl group (CH3) , or an ethyl group (CH3CH2) , etc.

Aryl refers to a hydrocarbon group that forms a ring structure characteristic of aromatic compounds such as, for example, benzene, naphthalene, phenanthrene,

25 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 C₆H₅.

30 The present invention utilizes a secondary rubber component in the thermoplastic elastomer composition. Most specifically, the secondary rubber is based on functionalized rubbers with a low Tg. The functionality is typically maleic anhydride, maleic acid, acyllactam,

35 ketone, carboxylic acid_r epoxy, or other functional groups (also referred to as a functionality) that can readily react with an amine, acid or amide in a 6

polyamide. The Tg of the secondary rubber is typically -3O⁰C or less, alternately -40 ⁰C or less, alternately -50 ⁰C or less. The functionality typically promotes reactive compatibilization between the secondary 5 rubber and the polyamide . leading to fine dispersion of secondary rubber with an average dispersion size of 1 μm or less, most particularly with a dispersion size of 0.5 μm or less. The low Tg helps ensure the softness of the secondary rubber at -20⁰C. Considering that most

10 functionalized rubber such as a maleated ethylene copolymer rubber and maleic anhydride grafted rubber is fairly permeable, it is desirable to keep the secondary rubber concentration low, preferably 20% by weight or less, most preferably 10% by weight or less. Maleic

15 anhydride grafted rubbers useful herein could be maleic anhydride modified or grafted ABS (acrylonitrile- butadiene-styrene) , EPDM (ethylene-propylene-diene), SEBS (styrene-ethylene/butadiene-styrene) and others. Other useful maleated ethylene copolymer rubbers include

20 maleated ethylene-propylene, maleated ethylene-butene, maleated ethylene-hexene, maleated ethylene-octene, maleated ethylene-decacene, maleated ethylene-propylene- diene, maleated ethylene-vinyl acetate, maleated ethylene-methyl aerylate, maleated ethylene-ethyl

25 acrylate, maleated ethylene-acylic acid and others.

Useful maleated copolyper rubbers also include copolymers of maleic anhydride or its derivatives with one or more comonomers such as ethylene, methacrylate, butyl acrylate, and the like.

30 In a preferred embodiment, the thermoplastic elastomer composition or the blend according to the present invention, which comprises the first rubber component dispersed in the polyamide matrix, is subjected to dynamic vulcanization.

35 ■ The term "dynamic vulcanization" is used herein to connote a vulcanization process in which the polyamide 7

resin and the first rubber component are vulcanized under conditions of high shear. As a result, the first vulcanizable rubber component is simultaneously vulcanized and dispersed as fine particles of a "micro 5 gel" within the polyamide resin matrix.

The dynamic vulcanization is effected by mixing the ingredients at a temperature which is at or above the curing temperature of the rubber in an equipment such . as a roll mill, Banbury^® mixer, continuous mixer, kneader or

10 mixing extruder, e.g., a twin screw extruder. The unique characteristic of the dynamically vulcanized composition is that, notwithstanding the fact that the rubber component may be partially or fully vulcanized, the composition can be processed arid reprocessed by a

15 conventional rubber processing technique such as extrusion, injection molding, compression molding, etc. Scrap or flashing can be salvaged and reprocessed.

The first rubber component usable in the present invention includes, for example, halogenated rubber. The

20 halogenated rubber is defined as a rubber having at least about 0.1 mole% halogen, such halogen selected from the group consisting of bromine, chlorine and iodine. Preferred halogenated rubbers useful in the present invention include halogenated isobutylene-based

25 homopolymers or copolymers. These polymers can be described as random copolymer of a C₄ to C₇ isoxnonoolefin derived unit, such as isobutylene derived unit, and at least one other polymerizable unit. In one embodiment of the present invention, the halogenated isobutylene-based

30 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

35 well known and are described in RUBBER TECHNOLOGY

209 - 581 (Maurice Morton ed., Chapman & Hall 1995), THE

VANDERBiLT RUBBER H&NDBOOK IQ5 - 122 (Robert F. ohm ed., 8

R. T. Vanderbilt Co., Inc. 1990), and Edward Kresge and H, C, Wang in 8 KIRK-OTHMER ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY 934 - 955 (John Wiley & Sons, Inc. 4th ed. 1993).

5 Butyl rubbers are typically prepared by reacting a mixture of monomers, the mixture having at least (1) a Cj to Ci₂ isoolefin monomer component such as isobutylene with (2) a multiolefin, monomer component. The isoolefin is in a range from 70 to 99.5% by weight of the total

10 monomer mixture in one embodiment, and 85 to 99.5% by weight in another embodiment. The multiolefin component is present in the monomer mixture from 30 to 0.5% by weight in one embodiment, and from 15 to 0.5% by weight in another embodiment. In yet another embodiment, from 8

15 to 0.5% by weight of the monomer mixture is multiolefin. The isoolefin is preferably a C4 to C_α2 compound, non- limiting examples of which are compounds such as isobutylene, isobutene, 2-methyl-l-butene, 3-methyl-l- butene, 2-methyl-2-butene, l^butene, 2-butene, methyl

20 vinyl ether, indene, vinyltrimethylsilane, hexene, and A- methyl-1-pentene. The multiolefin is a C₄ to Ci₄ multiolefin such as isoprene, butadiene, 2,3-dimethyl- 1,3-butadiene, myrcene, 6, 6-dimethyl-fulvene, hexadiene, cyclopentadiene, and piperylene, and other monomers such

25 as disclosed in EP 0 279 456 and US Patent No. 5,506,316 and 5,162,425. Other polymerizable monomers such as styrene and dichlorostyrene are also suitable for homopolymerization or copolymer!zation in butyl rubbers. One embodiment of the butyl rubber polymer useful in the

30 invention is obtained by reacting 95 to 99.5% by weight of isobutylene. with 0,5 to 8% by weight isoprene, or from 0.5 to 5.0% by weight isoprene in yet another embodiment. Butyl rubbers and methods of their production are described in detail in, for example, US Patent Nos.

35 2,356,128, 3,968,076, 4,474,924, 4,068,051 and 5,532,312.

Halogenated butyl rubber is produced by the 9

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 5 polymers are disclosed in U.S. Patent 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 60⁰C using bromine (Br≥) or chlorine

10 (CI₂) as the halogenation agent. Post-treated halogenated butyl rubber can also be used, as disclosed in US Patent No- 4,288,575. Useful halogenated butyl rubber typically has a Mooney Viscosity of about 20 to about 70 (Mlα₊s at 125°C) ; for example, and about 25 to about 55 in another

15 embodiment. The preferred halogen content is typically about 0.1 to 10% by weight based on the weight of the halogenated rubber; for example, about 0.5 to 5% by weight; alternatively, about 0.8 to about 2.5% by weight; for example, about 1 to about 2% by weight. A

20 particularly preferred form of halogenated butyl rubber contains a high content of the following halogenated structure, 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

25 halogen is chlorine:

-(-"CH₂-C-CH-CH₂-)- X

A commercial embodiment of a halogenated butyl 30 rubber useful in the present invention is Bromobutyl 2222 (ExxonMobil Chemical Company) . Its Mooney Viscosity is typically about 27 to 37 (MLi₊₈ at 125°C, ASTM 1646, modified), and its bromine content is about 1.8 to 2.2% by weight relative to the Bromobutyl 2222. Furthermore, 10

the cu-Ce characteristics of Bromobutyl 2222 as provided by the manufacturer are as follows: MH about 28 to 40 dN ro, MI. is about 7 to 18 dN m (ASTM D2084) . Another commercial embodiment of the halogenated butyl rubber 5 useful in the present invention is Bromobutyl 2255

(ExxonMobil Chemical Company) . Its Mooney Viscosity is about 41 to 51 {i.e., ML_α+8 at 125⁰C, ASTM D1646) , and its bromine content is about 1,8 to 2.2% by weight. Furthermore, its cure characteristics as disclosed by the

10 manufacturer are as follows: MH is from 34 to 48 dN m, ML_1+a is from 11 to 21 dN m (ASTM D2084) . Commercial isobutylene polymers are described in detail by R.N. Webb, T. D. Shaffer and A.H. Tsou, "Commercial Tsobutylene Polymers," Encyclopedia of Polymer Science and

15 Technology, 2002, John Wiley &' Sons, incorporated herein by reference.

Another useful embodiment of halogenated butyl rubber is halogenated, branched or "star-branched" butyl rubber. These rubbers are described in, for example, EP

20 0 678 529 Bl, U.S. Patent ttos. 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,

25 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

30 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.

In one embodiment, the SBB is a composition of butyl

35 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, 11

polybutadiene, polyisoprene, polypiperylene, natural rubber, styrene-butadiene rubber, ethylene-propylene diene rubber (EPDM) , ethylene-propylene rubber (EPM) , styrene-butadiene-styrene and styrene-isoprene-styrene 5 block copolymers. Polydienes can be present, based on the total monomer content in % by weight, typically greater than 0.3% by weight; alternatively, about 0.3 to about 3% by weight; or about 0.4 to 2.7% by weight.

Preferably the branched or "star-branched" butyl

10 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

15 US Patent 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 cationically reactive and

20 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

25 type of polydiene used to make the HSBB.

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

30 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

35 content in % by weight, typically greater than about 0.3% by weight, alternatively about 0.3 to 3% by weight, or about 0.4 to 2.7% by weight. 12

A commercial embodiment of HSBB useful in the present invention is Bromobutyl 6222 (ExxonMobil Chemical Company) , having a Mooney Viscosity (ML₁₊₈ at 125°C, ASTM D1646) of about 27 to 37, and a bromine content of about 5 2.2 to 2.6% by weight. Further, cure characteristics of Bromobutyl 6222, as disclosed by the manufacturer, are as follows: MH is from 24 to 38 dN-m, ML₁₊₈ is from 6 to 16 dN-m (ASTM D2084).

Preferred isoolefin/para-alkylstyrene copolymers

10 useful herein include random copolymers comprising a C« to C₇ isoolefin, such as isobutylene, and a halomethylstyrene. The halomethylstyrene may be an ortho-, meta-, or para-alkyl-substituted styrene. In one embodiment, the halomethylstyrene is a p-

15 halomethylstyrene containing at least 80%, more preferably at least 90% by weight o£ 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

20 alkyl substituent groups present on the styrene monomer units contain benzyliσ halogen or another functional group described further below. These interpolymers are herein referred to as "isoolefin copolymers comprising a halomethylstyrene" or simply "isoolefin copolymer."

25 Preferred isoolefin copolymers can include monomers selected from the group consisting of isobutylene or 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-

30 pentene. Preferred, isoolefin copolymers may also further comprise multiolefins, preferably a C< to C^ multiolefin such as isoprene, butadiene, 2,3-dimethyl-l, 3-butadiene, myrcene, 6,6-dime.thyl-fulvene, hexadiene, cyclopentadiene, and piperylene, and other monomers such

35 as disclosed in EP 279456 and US Patent Nos. 5,506,316 and 5,162,425. Desirable styrenic monomers in the isoolefin copolymer include styrene, methylstyrene, 13

chlorostyrene, methoxystyrene, indene and indene derivatives, and combinations thereof.

Preferred isoolefin copolymers may be characterized as interpolymers containing the following monomer units 5 randomly spaced along the polymer chain: 1. 2.

wherein R and R¹ are independently hydrogen, lower alkyl, preferably Cj to C₇ alkyl and primary or secondary alkyl

10 halides and X is a functional group such as halogen..

Desirable halogens are chlorine, bromine or combinations thereof, preferably bromine. Preferably R and R^α are each hydrogen. The -CRRiH and -CRRiX groups can be substituted on the styrene ring in either the ortho, meta, or para

15 positions, preferably the para position. Up to 60 mole% of the p-substituted styrene present in the interpolymer structure may be the functionalized structure (2) above in one embodiment, and in another embodiment from 0.1 to 5 πtole%. In yet another embodiment, the amount of

20 functionalized structure (2) is from 0.4 to 1 mole%. The functional group X may be halogen or some other functional group which may be incorporated by nuσleophilic substitution of benzylic halogen with other groups such as carboxylic acids; carboxy salts; carboxy

25 esters, amides and imides; hydroxy; alkoxide; phenoxide; thiolate? thioether; xanthate; cyanide; cyanate; amino and mixtures thereof. These functionalized isomonoolefin copolymers, tjieir method of preparation, methods of functionalization and cure are more particularly

30 disclosed in US Patent No. 5,162,445. 14

. Particularly useful of such copolymers of isobutylene and p-methylstyrene are those containing from 0.5 to 20 mole % p-methylstyrene wherein up to 60 roole% of the methyl substituent groups present on the benzyl 5 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 iualeic anhydride or by acrylic or methacrylic acid functionality. These interpolymers

10 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

15 "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.

20 These functional!zed 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

25 permeation chromatography (as shown in US Patent 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

30 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.

Preferred halogenated poly (isobutylene-co-p-

35 methylstyrene) polymers are brominated polymers which generally contain from about 0.1 to about 5% by weight of bromomethyl groups. In yet another embodiment, the 15

amount of bromomethyl groups is about 0.2 to about 2.5% by weight. Expressed another way, preferred copolymers contain about 0_*05 to about 2.5 mole% of bromine, based on the weight of the polymer, more preferably about 0.1 5 to about 1.25 mole % 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 C^ to C₇ isomonoolefin derived units, p- iuethylstyrene derived units and p-halomethylstyrene

10 derived units, wherein the p-halomethylstyrene units are present in the interpolymer from about 0.4 to about 1 mole% based on the interpolymer. In another embodiment, the p-halomethylstyrene is p-bromomethylstyrene. The Mooney Viscosity (MLi₊₈, 125°C, ASTM D1646) is about 30 to

15 about 60 Mooήey units.

In another embodiment, the relationship between the triad fraction of an isoolefin and a p-alkylstyrene and the mole% of p-alkylstyrene incorporated into the copolymer is described by the copolymer sequence

20 distribution equation described below and is characterized by the copolymer sequence distribution parameter, m.

F = 1 - {m A / (1 + snA) }

25 where: m is the copolymer sequence distribution parameter,

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

F is the p-alkylstyrene-isoolβfin-p- 30 alkylstyrene triad fraction in the copolymer. .

The best fit of this equation yields the value of m for σopolymerization of the isoolefin and p-alkylstyrene in a particular diluent. In certain embodiments, m is from 35 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; 16

alternatively, from 1-36; alternatively, from 1-35; and alternatively from 1-30. Copolymers having such ^' characteristics are disclosed in WO 2004-058825 and WO

2004-058835, 5 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 Cf'vis.avg.

10 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,

15 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 2004-058825 and WO 2004-058835.

20 In another embodiment, the relationship between the triad fraction of an isoolefin and a iuultiolefin and the mole% of multiolefin incorporated into the halogenated rubber copolymer is described by the copolymer sequence distribution equation below and is characterized by the

25 copolymer sequence distribution parameter, m.

F = m A / (1 + mA)^z where: m is the copolymer sequence distribution parameter,

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

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

35 Measurement of triad fraction of an isoolefin and a multiolefin and the mole% of multiolefin incorporated 17

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; 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

10 alternatively, m is about 1.20. Halogenated rubbers that have these characteristics are disclosed in WO 2004- 058825 and WO 2004-058835.

In another embodiment, the halogenated rubber is substantially free of long chain branching. For the

15 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

20 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 SEC as follows. The

25 presence or absence of long chain branching in the polymers is determined using triple detection SEC. Triple detection SEC is performed on a Waters (Milford, Massachusetts) 150C chromatograph operated at 4O⁰C equipped a Precision Detectors (Bellingham,

30 Massachusetts) PD2040 light scattering detector, a

Viscotek (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,

35 the viscometry detector second and the differential refractive index detector third. Tetrahydrofuran is used 18

as the eluent (0.5 ml/rain.) 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 5 Laboratories, Ltd.). Data is acquired with TriSEC software (Viscotek) and imported into Wavettetric's Igor Pro program (Lake Oswego_r OR) for analysis. Linear polyisobutylene is used to establish the relationship between the intrinsic viscosity [ηhinea_r determined by the 10 viscometry detector) and the molecular weight (M_w, determined by the light scattering detector) , The relationship between [η}u_rtear and M_w is expressed, by the Mark-Houwink equation.

IS [η] linear = KM_w ^α

Parameters K and α are obtained from the double- logarithmic plot of intrinsic viscosity against M_w, α is the slope, K the intercept. Significant deviations from

20 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 g*

25 also indicates deviations from the determined linear relationship.

[η ) sample = 9' CηJ linear

30 The value of g' is defined to be less than or equal to one and greater than or equal to zero. When g¹ 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

35 and G. C. Berry in "Comprehensive Polymer Science," Vol. 19

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'vis.avg, i≤ calculated 5 across the entire molecular weight distribution. The scaling factor g'vis.avg. is calculated from the average intrinsic viscosity of the sample:

g'vis.avg. = [η]avg. / (KM/) .

10

Other preferred halogenated elastomers or rubbers include halogenated isobutylene-p-methylstyrene^isoprene copolymer as described in WO 01/21672A1.

Preferred blends of the present invention typically

15 comprises a functionalized polymer (having one or more functional groups) as the second/polymer component/second rubber component. By "functionalized polymer" is meant that the polymer is contacted with a functional group, and, optionally, a catalyst, heat, initiator, and/or free

20 radical source, to cause all or part of the functional group to incorporate, graft, bond to, physically attach to, and/or chemically attach to the polymer. Accordingly, in one aspect, the functlocalized polymer useful in the present invention comprises the contact

25 product of a polymer, a functional group, and a functionalization catalyst (such as a catalyst, heat, initiator or free radical source) . Such functionalization is also referred to herein as grafting. Likewise, a functional group is also referred to herein

30 as a grafting monomer. Further, "functionalized polymer" is also defined to include polymer directly polymerized from monomers comprising olefin monomers and a monomer containing a functional group, (or using initiators having a functional group) to produce a polymer having a

35 functional group.

By the term "maleated" polymer. i$ meant a polymer 20

which has been contacted! with maleic acid or maleiσ anhydride, and_/ optionally, a catalyst, heat, initiator, and/or free radical source, to cause all or part of the maleic acid or maleic anhydride to incorporate, graft, 5 bond to, physically attach to, and/or chemically attach to the polymer.

By "functional group" is meant any compound with a weight average molecular weight of 1000 g/mol or less that contains a heteroatom and or an unsaturation.

10 Preferred functional groups include any compound with a weight average molecular weight of 750 or less, that contain one or more a hetero atoms and or one or more sites of unsaturation. Preferably the functional group is a compound containing a heteroatom and an

15 unsaturation, such as maleic anhydride or maleic acid. Preferred functional groups include organic acids and salts thereof, organic amides, organic iiaid.es, organic amines, organic esters, organic anhydrides, organic alcohols, organic acid halides (such as acid chlorides,

20 acid bromides, etc.) organic peroxides, organic silanes, and the like.

Examples of preferred functional groups useful in this invention include compounds comprising a carbonyl bond such as carboxylic acids, esters of carboxylic

25 acids, acid anhydrides, di-esters, salts, amides, and imides. Aromatic vinyl compounds, hydrolyzable unsaturated silane compounds, saturated halogenated hydrocarbons, and unsaturated halogenated hydrocarbons may also be used.

30 Examples of particularly preferred functional groups useful in this invention include, but are not limited, to maleic anhydride, citraconic anhydride, 2-methyl maleic anhydride, 2-chloromaleic anhydride, 2 , 3-dimethylκιaleic anhydride, bicyclo[2,2,l]-5-heptene-2,3-dicarboxylic

35 anhydride, and 4-methyl-4-cyclohexene-l,2-dicarboxylic anhydride, acrylic acid, methacryliσ acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic 21

acid, crotonic acid, bicyclo(2.2.2)oct~5-ene-2, 3- diσarboxylic acid anhydride, 1,2,3,4,5,8,9,10- octahydronaphthalene-2,3-diσarboxylic acid anhydride, 2- oxa~l,3-diketospiro(4.4)non-7-ene, bicyσlo(2.2.1)hept- 5- 5 ene-2,3- dicarboxylic acid anhydride, maleopiroaric acid, tetrahydrophtalic anhydride, norborn-5-ene-2,3- dicarboxylic acid anhydride, nadic anhydride, methyl nadic anhydride, himic anhydride, methyl himic anhydride, and x-methyl-bicyclo(2-2.1)hept"5-ene-2,3- dicarboxylic

10 acid anhydride (XMNA) .

In a preferred embodiment, the polymer is grafted with maleic anhydride so the maleie anhydride covalently bonded to the backbone polymer chain of the polymer. The anhydride functionality grafted onto the polymsr may

15 remain as an anhydride, may be oxidized into acid functional groups, and/or may be further reacted by processes known in the art to induce other functional groups such as amides, amines, alcohols, and the like. Multiple methods exist in the art that may be used

20 for functionalizing polymers. These include, but are not limited to, selective oxidation, free radical grafting, o∑onolysis, epoxidation, and the like. The functionalized polymer may be produced in a solution or a slurry process (i.e., with a solvent), or in a melt

25 process (i.e., without a solvent). The functionalized polymer may also be prepared in a high shear mixer, a fluidized bed reactor, and/or the like.

Typically, the polymer is combined with a free radical initiator and a grafting monomer at a

30 temperature, and for period of time sufficient to cause grafting of the monomer with the polymer to produce the functionalized polymer. In such an embodiment, the functionalized polymer may be obtained by heating the polymer and a radical polymerizable functional group

35 {e.g., maleic anhydride) in the presence of a radical initiator catalyst such as an organic peroxide. The combination is preferably heated at, near, or above the 22

decomposition temperature of the radical initiator catalyst .

Useful radical initiator catalysts include:, diacyl peroxides, peroxy esters, peroxy .ketals, dialkyl 5 peroxides, and the like. Specific examples include benzoyl peroxide, methyl ethyl ketone peroxide, tert- butyl peroxy benzoate, tert-butylperoxy acetate, 00-tert- butyl-Q-{2~ethylhexyl)-nonoperoxy carbonate, n-butyl 4,4- di~ (tert-butyl peroxy) valerate, 1,1-bis (tert-

10 butylperoxy)cyclohexane, 1, 1-bis (tert-butylperoxy) -3, 3, 5- triraethylcyclohexane, 2, 2-bis (tert-butylperoxy) butane, dicumylperoxide, tert-butylcumylperoxide, a, a'-bis (tert- . butylperoxy-isopropyl) benzene, di-tert-butylperoxide (DTBP), 2, 5-dimethyl-2,5-di (tert-butylperoxy) -hexane,

15 2, 5-dimethyl-2,5-di {tert-butylperoxy) -hexane, cyclohexanone peroxide, t-butylperoxyisopropyl carbonate, di-ti-butyl perphthalate, 2,5-dimethyl-2,5-di{t- butylρeroxy)heχene, 2, 5-dimethyl~2,5-di(t- butylperoχy)hexene-3, di-t-butyl peroxide, cumsne

20 hydroperoxide, t-butyl hydroperoxide, hydroperoxides, dxlauryl peroxide, dicumyl peroxide, and the like. In a preferred embodiment the functionalization is conducted at a temperature above the melting point of the polymer but below the decomposition temperature of the initiator.

25 Useful temperature ranges include from 35" C to 350° C, preferably from 40° C to 250° C, preferably from 45° C to

200° C

The radical initiator catalyst is preferably used in a ratio of from 0.00001 to 100% by weight, more 30 preferably from 0.1 to 10% by weight, based on the weight of the functional group. The heating temperature depends upon whether or not the reaction is carried out in the presence of a solvent, but it is usually from about 50⁰C to 350^βC. 35 In the solvent based process, the reaction may be carried out using the polymer in the form of a solution 23

or a slurry having a concentration of from 0.1 to 50% by weight in the presence of a halogenated hydrocarbon compound having 2 to 20 carbon atoms, an aromatic compound, a halogenated aromatic compound, an alkyl 5 substituted aromatic hydrocarbon, a cyclic hydrocarbon, and/or a hydrocarbon compound having 6 to 20 carbon atoms, which is stable to the radicals. Preferred solvents include hexane and cyclohexane.

Various techniques may be used to characterize the ^'

10 funσtionalized polymers, some of which are described in "Structure Characterization" The Science and Technology of Elastomers, F. Eirich, editor, Academic Press 1978, Chapter 3 by G. Ver Strate which is incorporated by reference.

15 Preferably, the functionalised polymer comprises roaleic anhydride at less than about 50% by weight, preferably less than about 45% by weight, preferably less than about 40% by weight, preferably less than about 35% by weight, preferably less than about 30% by weight,

20 preferably less than about 25% by weight, preferably less than about 20% by weight, preferably less than about 15% by weight, preferably less than about 10% by weight, preferably less than about 9% by weight, preferably less than about 8% by weight, preferably less than about 7% by

25 weight, preferably less than about 6% by weight, preferably less than about 5% by weight, preferably less than about 4% by weight, preferably less than about 3% by weight, preferably less than about 2% by weight maleic anhydride. Also preferably the level of maleic anhydride

30 in the polymer-g-MA may be greater than about 0.1% by weight, preferably greater than about 0.5% by weight, alternately greater than about 1% by weight maleic anhydride. In a preferred embodiment, the functionalized polymer may comprise 0.1 to about 10% by weight of the

35 maleic anhydride, more preferably 0.25 to about 5% by weight more preferably 0.5 to 4% by weight, more preferably 0.75 to 3.5% by weight, more preferably 1.5 to 24

2.5% by weight of the maleic anhydride.

The functional group content of the grafted polymer may be determined by Fourier Transformed Infrared spectroscopy based on a calibration with standards whose 5 absolute functional group content has been determined.

Specifically, the maleic anhydride content of the grafted polymer may be determined by Fourrier Transformed Infrared spectroscopy based on a calibration with standards whose absolute maleic anhydride content has

10 been determined according to the procedure described by M. Sclavons et al. (M. Sclavons, P. Fra.nquinet_r V. . Carlier, G. Verfaillie, I. Fallais, R. Legras, M. Laurent, and F. C, Thyrion, Polymer_r 41, 1989 (2000)) wherein a sample of functionalized polymer (polymer-g-Mk)

15 is first purified from residual monomer by complete solubilization in xylene followed by re-precipitation in acetone. This precipitated polymer. is then dried. Approximately 0.5 g of the re-precipitated polymer. is dissolved in 150 ml of toluene at boiling temperature. A

20 potentioitietric titration with TBAOH (tetra-butylammonium hydroxide) using bromothymol blue as the color indicator is performed on the heated solution in which the polymers do not precipitate during titration. The polymers are preferably pre-heated to 200 ⁰C for 1 hour prior to

25 dissolution in order to make sure that all diacid resulting from hydrolysis of maleic anhydride with ambient moisture has been converted back to the anhydride.

Polymers useful to make functionalized polymers

30 herein include ethylene polymers and propylene polymers. Particularly preferred polymers include polymers of ethylene copolymerized with one or more of propylene, butene, pentene, hexane, heptene, octane, nonene-deceήe, undecene, dodecene, methyl acrylate, ethyl acry.late,

35 butyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate, acrylic acid, methacrylic acid, ethacrylic acid, but acrylic acid, or vinyl acetate. Preferably 25

such ethylene polymers are modified with maleic acid or maleic anhydride. Another class of particularly preferred polymers include polymers of propylene copolymerized with one or more of ethylene, butene, 5 pentene, hexane, heptene, octane, nonene-decene, undecene, dodecene, methyl acrylate, ethyl acrylate, ' butyl acrylate, pentyl acrylate, hexyl acrylate, oσtyl acrylate, acrylic acid, methacrylic acid, ethacrylic acid, but acrylic acid, or vinyl acetate. Preferably

10 such propylene polymers are modified with maleic acid or maleic anhydride.

Another class of particularly preferred polymers include polymers of a C₄ to C₇ isoolefin (such as . isobutylene) copolymerized with one or more of isoprene,

15 isobutylene. Preferably such isobutylene polymers are modified with maleic acid or maleic anhydride. Particularly preferred functionalized polymer include maleated copolymers of isobutylene and isoprene, maleated copolymers of isobutylene and paramethylstyrne, maleated

20 . halobutyl type copolymers, maleated SBB type copolymers and maleated BlMS type copolymers.

Polyamides

Preferred polyamides usable as the matrix in the

25 present invention are thermoplastic polyamides (Nylons) comprising crystalline or resinous, high molecular weight solid polymers including copolymers and terpolymers having recurring amide units within the polymer chain. Polyamides may be prepared by polymerization of one or

30 more epsilon lactams such as caprolactam, pyrrolidione, lauryllactam and aminoundecanoic lactam, or amino acid, or by condensation of dibasic acids and diamines. Both fiber-forming and molding grade nylons are suitable. Examples of such polyamides are polycaprolactam

35 (Nylon 6) , polylauryllaσtam (Nylon 12) , polyhexamethyleneadipamide (Nylon 66) , polyhexamethyleneazelamide (Nylon 69) , 26

polyhexamethylenesebacamide (Nylon 610) , polyhexamethyleneisophthalamide (Nylon 6IP)_/ Nylon 46, Nylon MXD6, Nylon 6/66 and the condensation product of 11-aminoundecanoiσ acid (Nylon 11). Nylon 6 (N6), Nylon 5 11 (Nil), Nylon 12 (N12) , a Nylon 6/66 copolymer (N6/66) , Nylon 610 (N610), Nylon 46, Nylon MXD6, Nylon 69 and Nylon 612 (N612) may also be used. The copolymers thereof any blends thereof may also be used- Additional examples of satisfactory polyamides (especially those

10 having a softening point below 275°C) are described in

Kirk-Othmer, Encyclopedia of Chemical Technology, v. 10, page 919, and Encyclopedia of Polymer Science and Technology, Vol. 10, pages 392 - 414. Commercially available thermoplastic polyamides may be advantageously

15 used in the practice of this invention, with linear crystalline polyamides having a softening point or melting point between 160⁰C - 230⁰C being preferred.

The amounts of the first rubber component and the polyamide matrix usable in the present invention are

20 preferably 95 to 25 parts by weight and 5 to 75 parts by weight, more preferably 90 to 25 parts by weight and 10 to 75 parts by weight, respectively, provided that the total amount thereof is 100 parts by weight.

The method for producing the thermoplastic elastomer

25 composition in the present invention typically comprises mixing the first rubber component, the polyamide and the optional dispersion aid by a biaxial kneader/extruder etc. to disperse the rubber in the polyamide forming the continuous phase.

30 When vulcanizing the rubber, a vulcanization agent can be added, while mixing, and the rubber component is dynamically vulcanized. Further, the various compounding agents (except vulcanization agent) for the rubber and the polyamide may be added during the above kneading, but

35 preferably are mixed in advance before the kneading. The kneader used for mixing the polyamide and the rubber is not particularly limited. Examples thereof are a screw 27

extruder, kneader, Banbury mixer, biaxial kneader/extruder, etc. Among these, it is preferable to use a biaxial kneader/eκtruder for the mixing of the thermoplastic polyamide resin and the rubber and the 5 dynamic vulcanization of the rubber. Further, two or more types of kneaders may be used for successive . kneading. As the conditions for the melting and kneading, the temperature should be at least the temperature where the polyamide melts. Further, the

10 shear rate at the time of kneading is preferably 1000 to 7500 sec^"1. The time for the overall kneading is from 30 seconds to 10 minutes. Further, when adding a vulcanization agent, the vulcanization time after addition is preferably 30 seconds to 5 minutes. The

15 elastomer composition produced by the above method is then extruded or calendered into a film. The method of forming the film may be a usual method of forming a film from a thermoplastic resin or thermoplastic elastomer.. The elastomer composition according to the present

20 invention may contain, in addition to the above-mentioned essential ingredients, a vulcanization or cross-linking agent, a vulcanization or cross-linking accelerator, various types of oils, an antiaging agent, reinforcing agent, plasticizer, softening agent, or other various

25 additives generally mixed into general rubbers. The compounds are mixed and vulcanized by general methods to make the composition which may then be used for vulcanization or cross-linking. The amounts of these additives added may be made the amounts generally added

30 in the past so long as they do not run counter to the object of the. present invention.

Since the polyamide and the halogenated rubber differ significantly in solubility, a further optional compatibilizing ingredient may be useful for the purposes

35 of enhancing compatibility of these polymers. Such compatibilizers include ethylenically unsaturated nitrile-conjugated diene-based high saturation copolymer 28

rubbers (HNBR) , epoxylated natural rubbers (ENR) , NBR, hydrin rubbers, acryl rubbers and mixtures thereof. Compatibilizers are thought to function by modifying, in particular reducing, the surface tension between the^' 5 rubber and resin components. Other compatibilizers include copolymers such as tho$e having the structure of both or one of the polyamide and rubber polymer or a structure of a copolymer having an epoxy group, carbonyl group, halogen group, amine group, maleated group,

10 oxazoline group, hydroxy group, etc. capable of reacting with the polyamide or rubber polymer. These may be selected based upon the type of the tpolyamide and rubber polymer to be mixed, but useful copolymers typically include, e.g., a styrene/ethylene-butylene/styrene block

15 copolymer (SEBS) and its maleic acid-modϊfied form; EPDM, EPDM/styrene, or EPDM/acrylonitrile graft copolymer and their maleic acid-modified forms; styrene/maleic acid copolymer; reactive phenoxy thermoplastic resin; and their mixtures. The amount of the compatibilizer blended

20 is not particularly limited, but, when used, typically is about 0.5 to about 10 parts by weight, based upon 100 parts by weight of the polymer component, in other words, the total of the polyamide and rubber polymer.

With reference to the polymers and/or elastomers

25 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

30 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

35 to be considered "cured," "vulcanized" or "crosslinked." For example, for purposes of the present invention, a tire comprising an innerliner layer composition based on 29

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. 5 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.

10 Generally, polymer compositions, e.g., those used to produce tires, are crosslinked in the finished tire product. Crosslinking or vulcanization is accomplished by incorporation of curing agents and/or accelerators; the overall mixture of such agents being typically referred to

15 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

20 B.1. _t The Post Vulcanization Stabilization for NR_t 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

25 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 crosslinked by adding curative

30 agents, for example sulfur, metal oxides (i.e., zinc oxide, ZnO), organometallic compounds, radical initiators, etc. and heating the composition or mixture.

When the method known as "dynamic vulcanization" is used, the process of dispersing the cure system is modified

35 as described .in detail hereinafter. Generally, the term "dynamic vulcanization" is used to denote a vulcanization process in which a thermoplastic or engineering resin 30

(i.e. the polyamide) and at least one vulcanizable rubber are mixed under conditions of high shear and elevated temperature in the presence of a curing agent or curing system for the rubber (s). As a result, the rubber is 5 simultaneously crosslinked and dispersed as particles, preferably in the form of a microgel, within the polyamide which forms a continuous matrix. The resulting composition is known in the art as a ^'"dynamically vulcanized alloy" or DVA. Typically, dynamic

10 vulcanization is effected by mixing the ingredients at a .temperature which is at or above the curing temperature of the rubber, and at or above the melting temperature of the polyamide, using equipment such as roll mills, Banbury®- mixers, continuous mixers, kneaders, or mixing

15 extruders (such as twin screw extruders) . The unique characteristic of the dynamically vulcanized or cured composition is that, notwithstanding the fact that the rubber is cured the composition can be processed and reprocessed by conventional thermoplastic processing

20 techniques such as extrusion, injection molding, compression molding, etc. Scrap and or flashing can also be salvaged and reprocessed, In a typical dynamic vulcanization process, curative addition is altered so as to substantially simultaneously mix and vulcanize, or

25 crosslink, at least one of the vulcanizable components in a composition comprising at least one vulcanizable rubber, elastomer or polymer and at least one polymer or resin not vulcanizable using the vulcanizing agent (s) for the at least one vulcanizable component. (See, e.g., US Patent

30 No. 6,079,465 and the references cited therein.)

The following are common curatives that can function in the present invention: ZnO, CaO, MgO, AI₂O₃, CrO₃, . FeO/ Fe₂U₃, and NiO. These metal oxides can be used in conjunction with the corresponding metal stearate complex

35 (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 31

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 5 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

10 is used. Furthermore, because the present invention employs a DVA process, it is necessary that the properties ^■ of the cure system are adapted to the mixing process. Typically the first, or if there are more than two stages of rubber addition, then in a preceding stage, rubber (s)

15 are cured to a level of about 50% of the maximum cure which the particular rubber (s) and cure system are capable of reaching at the temperature of cure if measured independently of the dynamic vulcanization process in a time period that is less than about the mixer residence

20 time. 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_r e.g., on a two-roll mill, Banbury mixer or mixing extruder. _. A sample of the mixture, often

25 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 . .

30 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

35 an oscillating disc cure rheometer test (described in detail in American Society for Testing and Materials, Standard ASTM D2084). Having established the maximum 32

degree of cure, it is preferable to dynamically vulcanize the first or preceding stage rubber (s) added to the dynamically vulcanizable mixture to the extent that the degree of cure of such rubber {&) is selected from the 5 group consisting of about 50%, for example, about 60 % to greater than about 95 %; about 65 % to about 95 %; about 70 % to about 95 %; about 75 % to greater than about_, 90 %; about 80 % to about 90 %; in a time period less than or substantially equivalent to about the residence

10 time of the mixer used for dynamic vulcanization. Consequently, at the conclusion of the dynamic vulcanization process, the vulcanizable rubbers added to the composition are sufficiently cured to achieve the desired properties of the thermoplastic composition of

15 which they are a part, e.g., a fluid {air or liquid) retention barrier such as a innerliner for a tire. For purposes of the present invention, such state of cure can be referred to as "substantially fully cured."

It will be appreciated that the vulcanizable rubbers

20 will be cured to at least 50% of the maximum state of cure of which they are capable based on the cure system, time.and temperature, and typically, the state of cure of such rubbers will exceed 50% of maximum cure. Further, it may also be desirable to cure the rubber particles to

25 less than the maximum state of cure of which the rubber is capable so that the flexibility, as measured, for example, by Young*s modulus, of the rubber component is at a suitable level for the end-use to which the composition is to be put, e.g., a tire innerliner or hose

30 component. 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 aτ:e capable, as described above.

35 For purposes of dynamic vulcanization in the presence of an engineering resin to form, for example, a highly impermeable layer or film, any conventional curative 33

system which is capable of vulcanizing saturated or unsaturated halogenated polymers may be used to vulcanize at least the elastomeric halogenated copolymer of a Cj to C₇ isomonoolefin and a para-alkylstyrene, except that 5 peroxide curatives are specifically excluded from the practice of this invention when there is present one or more thermoplastic engineering resins such that peroxide would cause such resins themselves to crosslink. In that circumstance, if the polyamide would itself vulcanize or

10 crosslink, it would result in an excessively cured, non-thermoplastic composition. 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

15 or more of the following accelerators or vulcanizing agents: Permalux (the di-ortho-tolylguanidine salt of dicatechol borate) ; HVA-2 (m-phenylene bis inaleimide) ; Zisnet (2,4, 6-trimercapto-5-triazine) ; ZDBDC (zinc diethyl dithiocarbamate) and also including for the

20 purposes of the present invention, other dithiocarbamates,' Tetrone A (dipentamethylene thiuram hexasulfide) ; Vultac 5 (alkylated phenol disulfide) ; SP1045 (phenol formaldehyde resin); SP1056 (brominated alkyl phenol formaldehyde resin) ; DPPD (diphenyl

25 phenylene diamine) ; salicylic acid, ortho-hydroxy benzoic acid; wood rosin, abietic acid; and TMTDS (tetramethyl thiuram disulfide) , used in combination with sulfur.

Curative accelerators include amines, guanidines, thioureas, thiazoles, thiurams, sulfanamides,

30 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,

35 activators and polymers.- Ideally all of the available curative is consumed in the formation of effective crosslinks which join individual polymer chains to one 34

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 5 disulfide (TMTD), 4 , 4 ' -dithiodimorpholine (DTDM), tetrabutylthiuram disulfide (TBTD), 2,2^f-benzothiazyl disulfide (MBTS), hexamethylene-1, 6-bisthiosulfate disodium salt dihydrate, 2- (morphoϊinothio) benzothiazole (MBS or MOR), compositions of 90% MOR and 10% MBTS (MOR 90) ,

10 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

15 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

20 the cure system components in a step prior to addition of the rubber-containing composition to the thermoplastic using any mixing equipment commonly used in the rubber industry for such purpose, e.g., a two-roll rubber mill, a Banbury mixex, a mixing extruder and the like. Such mixing

25 is commonly referred to as "accelerating" the rubber composition. Alternatively, the rubber composition can be accelerated in a stage of a mixing extruder prior to carrying out dynamic vulcanization. It is particularly preferred that the cure system be dispersed in the rubber

30 phase, or in a rubber composition also optionally including one or more fillers, extenders and other common ingredients for the intended end-use application, prior to the addition of the rubber to the thermoplastic resin (s) in the mixing equipment in which it is intended to carry out dynamic

35 vulcanization.

In one embodiment of the invention, at least one curing agent is typically present at about 0.1 to about 35

15 phr (parts by weight per 100 parts by weight of the elastomer component); alternatively at about 0.25 to about 10 phr,.

Useful combinations of curatives, cure modifiers and 5 accelerators can be illustrated as follows: As a general rubber vulcanization agent, e.g., a sulfur vulcanization agent, powdered sulfur, precipitated sulfur, high dispersion sulfur, surface-treated sulfur, insoluble sulfur, dimorpholinedisulfide, alkylphenoldisulfide, and λO mixtures thereof are useful. Such compounds may be used ^■ in an amount of about 0.5 phr to about 4 phr. Alternatively, where the use of such a material is feasible in view of other polymer and resin components present an organic peroxide vulcanization agent,

15 ben≥oylperoxide, t-butylhydroperoxide,

2, 4-dichlorobenzoylperoxide, 2, 5-dimethy1^2, 5- di (t-butylperoxy) hexane_/ 2, 5-dimethylhexane-2, 5- di(peroxylbenzoate) , and mixtures thereof. When used, such curatives can be present at a level of about 1 phr

20 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

25 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),

30 magnesium oxide (about 0.5 phr to about 4 phr), lyserge (10 to 20 phr or so), p-quinonedioxime, p~ diber.2oylquinonedioxime, tetrachloro-p-benzoquinone, poly-p-dinitrosobenzene (about 0.5 phr to about 10 phr), methylenedianiline (about 0.05 phr to about 10 phr), and

35 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 36

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. 5

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

10 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,

15 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 may be present

20 at a level of from 0 to about 30 percent by weight of the rubber present in the composition.

Exfoliated, intercalated, or dispersed clays may also be present in the composition. These clays, also referred to as "nanoclays", are well known, and their

25 identity, methods of preparation and blending with polymers is disclosed in, for example, JP-&-2OO0-109635, JP-A-2000-109605, JP-A-11-310643; 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

30 materials suitable for the purposes of the present invention include natural or synthetic phyllosilicates, particularly smectic clays such as montmorillonite, nontronite, beidellite, volkonskoite, laponite, hectorite, saponite, sauconite, magadite, kenyaite,

35 stevensite and the like, as well as vermiculite, halloysite, aluminate oxides, hydrotalσite and the like. These layered clays generally comprise particles 37

containing a plurality of silicate platelets haying 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 5 cations such as Na⁺, Ca⁺², K⁺ or Mg⁺² present at the interlayer surfaces.

Layered clay may be intercalated and exfoliated by treatment with organic molecules (swelling agents) capable of undergoing ion exchange reactions with the

10 cations present at the interlayer surfaces of the layered silicate. Suitable swelling agents include cationic surfactants such as, ammonium, alkylamines or alkylammonium (primary, secondary, tertiary and quaternary) , phosphonium or sulfonium derivatives of

15 aliphatic, aromatic or arylaliphatic amines, phosphines and sulfides. Desirable amine compounds (or the corresponding ammonium ion) are those with the structure RiR₂RsN, wherein R₁, R₂, and R₃ are C₁ to C₃₀ alkyls or alkenes which may be the same or different. In one

20 embodiment, the exfoliating agent is a so-called long chain tertiary amine, wherein at least Ri is a C₁₂ to C₂o alkyl or alkene.

Another class of swelling agents include those which can be covalently bonded to the interlayex surfaces.

25 These include polysilanes of the structure -Si (R¹J₂R² where R^τ 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

30 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 US Patent Nos. 4,472,538, 4,810,734,

35 4,889,885 and WO92/02582.

In a preferred embodiment of the invention, the exfoliating or swelling agent is combined with a 38

halogenated polymer. In one embodiment, the agent includes all primary, secondary and tertiary amines and phosphines; alfcyl and aryl sulfides and thiols; and their polyfunctional versions. Desirable additives include: 5 long-chain tertiary amines such as N,N-dimethyl- octadecylamine, N,N-dioctadecyl~:methylamine, dihydrogenated tallowalkyl-raethylamine and the like, and amine-terminated polytetrahydrofuran; long-chain thiol and thiosulfate compounds such as hexamethylene sodium

10 thiosulfate. In another embodiment of the invention, improved interpolymer impermeability is achieved by the use of polyfunctional curatives such as hexamethylene bis (sodium thiosulfate} and hexamethylene bis(cinnamaldehyde) .

15 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 or barrier properties of the composition, e.g. tensile strength or

20 air/ojcygen permeability. Amounts typically can be from about 0.5 to about 15% by weight in one embodiment, or about 1 to about 10% by weight in another embodiment, and about 1 to about 5% by weight in yet another embodiment, based on the polymer content of the composition.

25 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.

30 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

35 composition during preparation of the layer, e.g., mixing, calendering, etc. Suitable plasticizer oils include aliphatic acid esters or hydrocarbon plasticizer 39

oils such as paraffinic or naphthenic petroleum oils. The preferred plastiσiser oil for use in standard, non-DVA, non-engineering resin-containing innerliner compositions is a paraffinic petroleum oil; suitable hydrocarbon plasticizer oils for use in such innerliners include oils having the following general characteristics.

10 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

15 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 C₄ raffinate. Low molecular weight "polybutene" polymers is described in, for example, SYNTHETIC LUBRICANTS AND HIGH-PERFORMANCE FUNCTIONAL

20 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

25 Company, Houston TX, now available from Infineum

International Limited, Milton Hill, England under the "INFINEUM c, d, f or g tradename) , including gxades previously identified as PARAPOL™ 4.50, 700, 950, 1300, 2400, and 2500. Additionally preferred polybutene oils 40

are SUNTEX™ polybutene oils available from Sun Chemicals. Preferred polybutene processing oils are typically synthetic liquid polybutenes having a certain molecular weight, preferably from about 420 Mn to about 2700 Mn. 5 The molecular weight distribution -Mw/Mn- (^rtMWD") 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

10 (CG/G) for preferred polybutene oils ranges from about 40 for the 450 Mn process oil, to about 8 for the 2700 Mn process oil.

Rubber process oils also have ASTM designations depending on whether they fall into the class of

15 paraffinic, naphthenic or aromatic hydrocarbonaceous process oils. The type of process oil utilized will be that customarily used in conjunction with a type of elastomer component and a rubber chemist of ordinary skill in the art will recognize which type of oil should

20 be utilized with a particular rubber in a particular application. For an innerliner composition the oil is typically present at a level of 0 to about 25% by weight; preferably about 5 to 20% by weight of the total composition. For a thermoplastic elastomer composition

25 the oil may be present at a level of 0 to about 20% by weight of the total composition; preferably oil is not included in order to maximize impermeability of the composition.

In addition, plasticizers such as organic esters and

30 other synthetic plasticizers can be used. A particularly preferred plasticizer for use in a DVA composition is N-butylsulfonamide or other plasticizers suitable for polyamides. In another embodiment, rubber. process .oils such as naphthenic, aromatic or paraffinic extender oils

35 may be present at about 1 to about 5 phr. In still another embodiment, naphthenic, aliphatic, paraffinic and other aromatic oils are substantially absent from the 41

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.

5 The degree of cure of the vulcanized rubber can be described in terms of gel content, cross-link density, the amount of extractable components or it can be based on the state of cure that would be achieved in the rubber were it to be cured in the absence of the resin. For

10 example, in the present invention, it is preferred that the halogenated elastomer achieve about 50 to about 85% of full cure based on the elastomer per se as measured, e.g., by tensile strength or using the oscillating disc cure meter test (ASTM D 2084, Standard Test Method for

15 Rubber Property-Vulcanization Using Oscillating Disk Cure Meter) .

By molding the thermoplastic elastomer composition obtained into a sheet, film, or tube using a T-sheeting die, straight or crosshead structure tubing die,

20 inflation molding cylindrical die, etc. at the end of a single-screw extruder, or by calendering, it is possible to use the composition as the air permeation preventive layer, e.g., an innerliner, of a pneumatic tire and as a component or layer of a hose, etc. The thermoplastic

25 elastomer compositions of the present invention may be taken up into strands once, pelletized, then molded by using a single-screw extruder that is typically used for resin.

The sheet or tubular molded article thus obtained

30 can be effectively used for an innerliner layer of a pneumatic tire or the hose tube or hose cover of a low gas permeable hose. Furthermore, the low permeability characteristics of the composition are suitable for uses with fluids other than gasses, e.g., liquids such as

35 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. 42

Any. range of numbers recited in the specification hereinabove or in the paragraphs and claims hereinafter, referring to various aspects of the invention, such as that representing a particular set of properties, units 5 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

10 "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

15 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

20 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,

25 In another embodiment, this invention relates to:

1. A blend, preferably dynamically vulcanized, comprising a first rubber component at least partially . vulcanized dispersed as particles having a size of 1

30 micron or less, alternately 0.75 microns or less, alternately 0.50 microns or less, in a polyamide matrix; and a second polymer component different from the first rubber component, where the second polymer component has a Tg spread of less than 20 ⁰C, preferably less than 15 .

35 ⁰C, as measured by DMTA run at 10 ⁰C per minute at 1 hertz, a Tg of -20 ⁰C or less, preferably -4O⁰C or less, 43

more preferably -50 ⁰C or less, a weight average molecular weight greater than 20,000, preferably from 30,000 to 1,000,000, more preferably from 50,000 to 750,000, and comprises at least 0.1 to 25% by weight, preferably from 5 0.1 to 15% by weight, more preferably 0.5 to 10% by ^■ weight, of a functional group, based upon the total weight of the second polymer component.

2. The blend of paragraph 1, wherein the second 10 polymer component is present in the blend at 0.1 to 25% by weight, preferably 0.5 to 20% by weight, more preferably 1 to 15% by weight, based on the weight of the blend.

15 3. The blend of paragraph 1 or 2, wherein the functional group comprises or is derived from a carboxylic acid (such as maleic acid), an anhydride (such as maleic anhydride), an acyllactam, a ketone, an epoxy, or any other functional group that can readily react with

20 an amine, acid or amide in. a polyamide, regardless of whether a catalyst or promoter is necessary to assist in the reaction with the amine, acid or amide of the polyamide.

25 4. The blend of paragraph 1 or 2, wherein the functional group is or is derived from maleic acid or maleic anhydride.

5. The blend of paragraph 1, 2, 3> or 4, wherein 30 the second polymer component is selected from the group consisting of maleic anhydride grafted ethylene copolymers, maleic anhydride co-polymerized ethylene copolymers .

35 6- The blend of paragraph 1/2, 3, 4, or 5, wherein the second polymer component is selected from the group consisting of maleic anhydride modified or grafted 44

acrylonitrile-butadiene-styrene, maleic anhydride modified or grafted ethylene-propylene-diene monomer rubber) , maleic anhydride modified or grafted styrene- ethylene/butadiene-styrene rubber. 5

7. ^• The blend of paragraph 1, 2, 3, 4, or 5, wherein the second polymer component is selected from the group consisting of maleated ethylene-propylene copolymer, maleated ethylene-butene copolymer, maleated

10 ethylene-hexenecopolymer, maleated ethylene- oσteneσopolymer, maleated ethylene-deσacenecopolymer, maleated ethylene-vinyl acetate copolymer, maleated ethylene-methyl acrylate copolymer, maleated ethylene- ethyl acrylate copolymer, maleated ethylene-acylic acid

3,5 copolymer, maleated ethylene butyl acrylate copolymer, and mixtures thereof.

By "second polymer component different from the first rubber component" is meant that the rubbers and

20 polymers comprise different molecular weights (by more than 20,000 Daltons, preferably by more than 30,000 Daltons) , different functional groups, different monomers . and or comonomers or if they have the same comonomer, then they have comonomer contents that are not within 2%

25 by weight of each other. For example a BlMS copolymer having 3% by weight para-methyl styrene (PMS) and 5% by weight bromine is considered different from a BIMS copolymer having 11% by weight PMS and 5% by weight bromine. Likewise a BIMS copolymer having 3% by weight

30 para-methyl styrene (PMS) and 5% by weight bromine is considered different from a maleated BIMS copolymer having 3% by weight PMS and 5% by weight bromine. In an alternate embodiment the first rubber component and the second polymer component differ in permeability, at 60⁰C

35 (measured by Mocon tester in unit of cc-mils/m^day-mmHg) by at least 10%, preferably by at least 20%, preferably by at least 25%, preferably by at least 30%. In another 45

alternate embodiment the first rubber component and the second polymer component differ in Tg spread. Preferably the first rubber component has a Tg spread of greater than 20 ⁰C (preferably greater than 30 ⁰C, preferably

5 greater than 40 ⁰C as measured by DMTA run at 10 ⁰C per minute at 1 hertz) and the second polymer component has a Tg spread of less than 20 ⁰C (preferably less than 15 ⁰C, as measured by DMTA run at 10 °C per minute at 1 hertz) . Glass transition appears as a peak in the plot of loss 10 tangent as a function of temperature determined by running temperature-scan dynamic mechanical (DMTA) testing of a polymer. The glass transition spread (also called Tg spread) is defined as the temperature spread from the onset of the glass transition to its ending. 15 The definitions of the onset and the ending of a glass transition are the intercepts of loss tangent base line to the line tangents of either the uphill glass transition peak slope or the downhill glass transition peak slope, respectively. 20

Examples

The present invention will now be further illustrated by, but is by no means limited to, the following Examples.

25 The following commercially available products were used for the components employed in the Examples. 1. Resin Component

Nll-1 (Nylon 11) : Rilsan BMN O (Atochem) . Nll-2: Rilsan BESN 0 TL (AtochβπO . 30 N6/66-1 (Nylon 6/66 copolymer) : ϋbe 5033B (Ube) .

N6/66-2 (Nylon 6/66 copolymer): CM 6001FS (Toray) . Rl: Reactive softener 1, AR201, maleated EVA copolymer, Tg = -35*C (Mitsui-DuPont) . R2: Reactive softener 2, Exxelor 1803, maleated EP 35 copolymer, Tg = -55⁰C (ExxonMobil Chemical) . 46

R3: Reactive softener 3, Exxelor 1840, maleated EO copolymer, Tg - -5O⁰C (ExxonMobil Chemical) . ^" Pl: Plasticizer 1, BM4, N-butylsulfonamide

(Daihachi Chemical) .

5 . P2: . Plasticizer 2, low Mw polyamide, "Unirez 2653," density— 0.96, softening point=95~105 ⁰C, viscosity at 200 ⁰C - 7.5 Pa-s (Arizona Chemical) .

• P3: Plasticizer 3, low Mw polyamide, "Unirez 2633," 10 density = 0.97, softening point=127-137 ⁰C, viscosity at 200 ⁰C = 4.3 Pa-s (Arizona Chemical) , Sl: Stabilizer package, includes Irganox (Ciba) ,

Tinuvin (Ciba) , and CuI (Nihon Kagaku-Sangyo) 15 2. Rubber Component

' BIMS: Exxpro™ 89-4 (brominated isobutylene p-methyl styrene copolymer, 0.75% Br, 5% PMS, (ExxonMobil Chemical)

ZnO: Zinc oxide curative

20 St-acid: Stearic acid curative ZnSt: Zinc sterate curative

G¹, storage shear modulus, was measured by using a Rheometric ARES rheometer at 1 Hz in torsional mode with

25 temperature scan.

Dispersion size (also called particle size) was determined based on the number average equivalent dispersion diameter in microns calculated from image processing the tapping phase AFM morphological images of

30 the sample.

M50 at RT means 50% modulus measured at room temperature (RT) according to ASTM D412-92;

M50 at -20 ⁰C means 50% modulus measured at -20 ⁰C according to ASTM D412-92.

35 Permeability: oxygen permeability at 60*C measured by Moσon tester in unit of co-mils/m²-day-mmHg 47

Using a Brabender internal mixer running at 220⁰C and 60 rpm, softeners of 10% by weight were added into . N6/66-1, as shown in Table I, for a 4-minute mix time. 5 The P2 low MW polyamide can soften the Nylon matrix as indicated in Table I in addition to its ability in plasticizing, or lowering the viscosity, of Nylon. However, without the reactive groups on P2. that can compatibilize the blends, moderate P2 dispersions were

10 obtained in N6/66-1 blended with 10% by weight of P2. In addition, the enlargement of the BIMS dispersion was indicated., as tabulated in Table II, in the presence of P2 in blends of Nylons and BIMS. This enlargement can be avoided simply by using reactive σompatibilized

15 softeners . Comparing the modulus values of Examples 3 - 5, the reactive~compatibilized softener with the lowest Tg, or Exxelor 1803, is most efficient in bringing down the modulus of the final blend or in the_^ability to soften the Nylon.

20

48

Table I: Properties of blends of N6/66-1 with 10 wt % reactive softener

The blends of Examples 6 to 8 were prepared using a Brabender internal mixer at 220*C and 60 RPM. The nylon was added first with BIMS added 1 minute after. The additive was added 2 minutes after the nylon and the total mix time was 5 minutes.

10

Table II; Properties of 60/30/10 blends of N6/66-l/BIMS/softener

15 This enlargement of BIMS dispersion in the presence of low MW polyamide plasticizers is further exemplified in Table III in twin-screw extrusion mixed and dynamic vulcanized blends of Nylons and BIMS. The BIMS dispersions become larger and mixing quality becomes

20 worst with increasing loading of P3.

In preparing the DVA blends of Examples 9 to 18, the elastomer components, BIMS and curatives, were first compounded in a Banbury internal mixer running at 100 RPM 49

and dumped at 100⁰C. These blends were then granulated and fed into a ZSK-30 twin screw extruder along with pre- blended nylons and reactive softener in one step at the feed hopper. The pre-blended nylons were palletized nylons that were twin-screw blended with stabilizers and plasticizers. Pre-blended nylons were dried to remove moisture prior to reactive blending and dynamic vulcanisation with BIMS.

10 Table III; Dispersion enlargement by low MW polyamide in twin-screw extrusion mixed Nylon/BIMS vulcanized blend

15 NM: cannot be measured

As shown in Table IV, plasticizer of either Pl or . P3 was added in all blends to lower the Nylon viscosity for incorporation of more rubbers. However, without the

20 secondary softening rubber of R3, the BlMS rubber coalesces at high concentrations as indicated in Example 16. By utilizing both the softening rubber and BIMS 50

rubber, higher rubber loading can be accomplished without phase inversion as demonstrated by Example 17. Through judicious selection of regular plasticizer of Pl instead of P3, fine BIMS rubber dispersions can be acquired at high rubber loading and with very low modulus values.

Table IV: Properties of twin-screw extrusion mixed

Nylon/BIMS vulcanized blends with , softeners

10

*: Total rubber weight percent includes both the BIMS rubber and the reactive-compatilizable rubber softerner.

15

All documents described herein are incorporated by reference herein, including any priority documents and/or testing procedures to the extent they are not

20 inconsistent with this text. The principles, preferred embodiments, and. modes of operation of the present 51

invention have been described in the foregoing specification. Although the invention herein has been deseribed with reference to particular embodiments, it is to be understood that these embodiments are merely 5 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 10 present invention as defined by the appended claims.

Likewise, the term "comprising" is considered synonymous with the term "including" for purposes of Australian law.

Claims

52

1. A thermoplastic elastomer composition comprising a thermoplastic elastomer composed of at least partially vulcanized first rubber component discretely 5 dispersed in a polyamide matrix and a secondary rubber component, which is different from the first rubber component, having a glass transition temperature Tg of -3O⁰C or, less.

10 2. The thermoplastic elastomer composition as claimed in claim 1, wherein said secondary rubber component has a substituent group capable of reacting with a polyamide.

15 3. The thermoplastic elastomer composition as claimed in claim 2, wherein said secondary rubber component is selected from the group consisting of maleic anhydride modified ethylene-propylene, maleiσ acid modified ethylene-propylene, ethylene-butene, ethylene-

20 octene, ethylene-ethyl acrylate,_acrylonitrile-butadiene- styrene, ethylene-propyleiαe-diene and styrene- ethylene/butadiene-styrene.

4. The thermoplastic elastomer composition as 25 claimed in claim 1, comprising 100 parts by weight of the thermoplastic elastomer and 20 parts by weight or less of the secondary rubber component.

5_j_ The thermoplastic elastomer composition as 30 claimed in claim 1, wherein the dispersed particle size of the secondary rubber component is 1.0 μm or less.

6__;_ The thermoplastic elastomer composition as claimed in claim 1, wherein the .secondary rubber 35 component comprises maleiσ anhydride grafted ethylene copolymers, maleic anhydride co-polyπιerized ethylene copolymers_/ or any elastomers with a functional group 53

reactive to any functional group {amine, acid, or amide) in polyand.de.

1. Α blend comprising a first rubber component at 5 least .partially vulcanized dispersed as particles having a size of 1 micron or less in a polyamide matrix; and a second polymer component different from the first rubber component, where the second polymer component has a Tg spread of less than 20 ⁰C as measured by DMTA run at 10 ⁰C

10 per minute at 1 hertz, a Tg of -20 "C or less, a weight average molecular weight greater than 20,000 and comprises at least 0.1 to 251 by weight of a functional group, based upon the total weight of the second polymer component .

15 ^■

8. The blend as claimed in claim 7, wherein the second polymer component is present in the blend at 0.1 to 25% by weight, based on the weight of the blend.

20 9. The blend as claimed in claim 7, wherein the functional group is derived from a carboxylic acid, an anhydride, an acyllactam, a ketone, an epoxy, or any other functional group that can readily react with an amine, acid or amide, in a polyamide.

25

10. The blend as claimed in claim 7, wherein the functional group is derived from maleic acid or maleic anhydride.

30 11. The blend as claimed in claim 7, wherein the second polymer component is selected from the group consisting of maleic anhydride grafted ethylene copolymers, maleic anhydride co-polymerized ethylene copolymers and mixtures thereof.

35

12. The blend as claimed in claim 7, wherein the second polymer component is selected from the group 54

consisting of maleic anhydride modified or grafted aσrylonitrile-butadiene-styrene, maleic anhydride modified or grafted ethylene-propylene-diene monomer rubber) , maleic anhydride modified or grafted styrene- 5 ethylene/butadiene-styrene rubber and mixtures thereof.

13. The blend- as claimed in claim 7, wherein the second polymer component is selected from the group consisting of maleated ethylene-propylene copolymer,

10 malea.ted ethylene-butene copolymer, maleated ethylene-- hexenecopolymer, maleated ethylene-octenecopolymer, maleated ethylene-decacenecopolymer,._. maleated ethylene- vinyl acetate copolymer, maleated ethylene-methyl acrylate copolymer, maleated ethylene-ethyl acrylate

15 copolymer, maleated ethylene-acylic acid copolymer, maleated ethylene butyl acrylate copolymer and mixtures thereof, .