KR20030008157A - Method for preparing silica filled elastomeric compositions - Google Patents

Abstract

The present invention relates to a process wherein a) a copolymer of C ₄ to C ₇ isoolefins and para-alkylstyrene is mixed with silica, and b) a general purpose rubber is mixed separately with silica, wherein at least one silane coupling agent is silica / copolymer or silica. / Mixing with at least one of the general purpose rubber blends, and c) mixing the silica / copolymer blend with the silica / general purpose rubber blend. Common silane coupling agents include bis (3-triethoxysilylpropyl) tetrasulfide, 3-thiocyanato-propyl-triethoxysilane, 3-mercaptopropyl-trimethoxy silane, one of the copolymers An embodiment of is a terpolymer of isobutylene, para-methylstyrene and bromo-paramethylstyrene.

Description

METHODS FOR PREPARING SILICA FILLED ELASTOMERIC COMPOSITIONS

Automotive manufacturers' demand for tire performance is still increasing. In addition to meeting functional requirements such as low rolling resistance, high wet traction and wear resistance, today's tires are increasingly important for standards such as appearance and tire noise and handling. The particular rubber composition used for each use varies widely in its physical properties, but one unchanging property is its color. Most rubber compositions are black. In addition, most rubber compositions eventually discolor due to heat, light, ozone and the like. This is especially true for rubbers used in applications where stress is required such as tire sidewalls.

Subsequently, a copolymer of brominated isobutylene and para-methylstyrene (BIMS copolymer) can be used for tire sidewalls, among other applications. A commercial aspect of BIMS polymers is EXXPRO® elastomer (ExxonMobil Chemical Company, Houston, TX). One of the major advantages of using BIMS polymers in tire sidewalls is that the tires retain a good gloss black when carbon black is used as filler. Because of the high stability of the BIMS polymer, it is not necessary to use any antioxidant or ozone resistant agent as one of the elastomeric components in the tire sidewall compound containing the BIMS polymer. Thus, no discoloration of conventional general-purpose rubber (GPR) tire sidewalls associated with blooming of these additives occurs.

Those skilled in the art will point to the presence of "carbon black" which is used as a reinforcing filler as the main reason why most rubbers are black. This is true, but carbon black is not the only cause. In fact, a wide variety of other fillers, hardeners, antidegradants, oils and the rubber itself can all produce dark colors, making it virtually impossible to color. This is evidenced by the fact that rubber discolors even in compositions where carbon black is replaced by silica filler. For example, EP 0 682 071 B1 discloses a still dark silica reinforced tire tread due to the presence of aromatic processing oils, coupling agents, anti-degradants and vulcanization systems. In fact, it is unclear how many components present in the rubber composition must be changed to produce a colorable composition.

Of course, there are several colorable elastomeric compositions. The white sidewalls on the tire are in the form of colorable rubber. White is achieved by using fillers such as silica, clay, talc and carbonate instead of carbon black and adding titanium dioxide as whitening pigment. However, white comes with a cost. The filler produces a weaker rubber composition that is more brittle than carbon black and consequently does not reinforce tires. Thus, the rubber used for the white sidewalls is limited in its usefulness.

WO 99/31178 also discloses a transparent, colorable elastomeric composition containing a copolymer of C ₄ to C ₇ isoolefins with para-alkylstyrene, silica and a coupling agent. Other related patents include U.S. Patent Applications 09 / 691,764, U.S. Patent Nos. 5,817,719, 6,201,054 B1, 6,177,503, and Japanese Patent 09324069, filed Oct. 18, 2000, assigned to the assignee of the present invention. have. In particular, U. S. Patent No. 5,817, 719 to Zanzig et al. Discloses rubber / para-methylstyrene copolymer mixtures containing silica and silane coupling agents but do not provide a means for mixing these species to reach the intended blend. I couldn't.

However, unlike carbon black, many elastomers and inferior silica interactions of silica and silica compositions and elastomers have low rolling resistance, as evidenced by the mechanical properties of Tan values at -30 ° C, 0 ° C and 60 ° C. And optimum properties in tires such as high wetland traction. Low rolling resistance is evidenced by low or reduced Tan δ at 50 to 70 ° C., while high wetland traction is demonstrated by high or increased Tan δ at 0 to 10 ° C. Accordingly, the problem remains in the industry to provide colorable elastomeric compositions having the advantages of low rolling resistance and high wettability for use in tires, belts, hoses and other applications.

Summary of the Invention

Other problems, including the above, have been solved in the present invention, which provides a method of combining an isoolefin / para-alkylstyrene copolymer and GPR with a silica filler by a silane coupling agent to form an elastomeric composition or “blend”. . More specifically, effective silane coupling agents to obtain desirable viscoelastic properties of silica filled compounds for low rolling resistance (low Tan δ at 50 to 70 ° C.) and high wettability (Tan δ at 0 to 10 ° C.). Highly dispersible silica is used together.

One embodiment of the invention incorporates a silane coupling agent (or “silane”) with a composition containing silica and isoolefin / para-alkylstyrene copolymers, as compared to a similar compound filled with N220 or N660 black. To a polymer composition having a high Tan δ at 10 ° C. and a low Tan δ at 50-70 ° C. The results obtained are that the silane can act as an effective coupling agent between the isoolefin / para-alkylstyrene copolymer and silica, as evidenced by a significant increase in the ratio of 300% modulus to 100% modulus of the compound. Unlike in the case of carbon black filled isoolefin / para-alkylstyrene copolymers, the coupling between the isoolefin / para-alkylstyrene copolymer and silica remains at high temperature. This allows the silica filled compound to maintain its elasticity and low rolling resistance as the temperature increases.

FIELD OF THE INVENTION The present invention relates to a process for preparing silica filled elastomer blends, and more particularly, comprising copolymers of C ₄ to C ₇ isoolefins with para-alkylstyrene, universal rubber, silica and one or more silane coupling agents. A method of making a colorable elastomeric composition.

1 is a representative plot of temperature as a function of time during a typical production cycle of silica filled polymers.

In one embodiment of the present invention, as a blend of general purpose rubber, para-alkylstyrene based copolymer, silicone and silane coupling agent, it is manufactured that is colorable and retains the property to allow the composition to be used as a reinforcing member in automobile tires. do. As used herein, the term "colorable" refers to the ability of the basic elastomeric composition or "blend" to be colored to yield blends of various colors. These blends generally do not contain carbon black. The term "blend" refers to a copolymer, a general purpose rubber, a mixture of silicone and silane coupling agents, or a mixture of two or more of these components. "Masterbatch" is a mixture of copolymer / silicone / silane coupling agent or general purpose rubber / silicone / silane coupling agent and the blend is a mixture of masterbatches.

One embodiment of the blend includes copolymers of isoolefins and para-alkylstyrenes, general purpose rubbers (GPR) such as natural rubber and silica, which have been reacted in the presence of silane coupling agents such as silane-crosslinkers. The colorable rubber blend of the present invention comprises a copolymer of one or more C ₄ to C ₇ isoolefins with para-alkylstyrene (hereinafter referred to as “copolymer”). More preferably, the copolymer is a terpolymer of isobutylene, para-methylstyrene and bromo para-methylstyrene (BIMS).

One embodiment of the invention is also a method of combining the components of the blend, wherein the BIMS copolymer is mixed with silica and optionally one or more coupling agents by any standard means to form a silica / copolymer blend, and a general purpose rubber Is mixed separately with silica and one or more silane coupling agents to form a silica / general rubber blend, and then the silica / copolymer blend is mixed with the silica / general rubber blend.

Isoolefins and para-alkylstyrene copolymer components

Copolymers of C ₄ to C ₇ isoolefins with para-alkylstyrenes of the invention also include terpolymers of C ₄ to C ₇ isoolefins, para-alkylstyrenes and halogenated para-alkylstyrenes. In one embodiment, the elastomeric component is a terpolymer (BIMS) of isobutylene, para-methylstyrene and bromo-para-methylstyrene, as disclosed in US Pat. No. 5,162,445. The isoolefin / para-alkyl styrene copolymers generally contain from about 0.5 to about 20 weight percent of isoolefins of 4 to 7 carbon atoms and para-alkylstyrene, wherein about 0.01 of the methyl groups present on the benzene ring of para-alkylstyrene To about 60 mole% comprises a halogen atom. The percentage of para-alkylstyrene and halogenation can vary. Different applications may require dramatically different formulations. In general, the copolymers of the present invention comprise from 2 to 20% by weight of para-alkylstyrene (preferably para-methylstyrene). In addition, the copolymer of the present invention has 0.20 to 3.0 mol% of halogenated compounds such as bromomethylstyrene.

Generally, low amounts of bromine and / or para-alkylstyrene are used. In one embodiment, para-alkylstyrene (preferably para-methylstyrene) comprises 5-10% by weight of the copolymer. In one embodiment, it comprises about 5% by weight of the copolymer. In another embodiment, the halogenated compound, such as bromomethylstyrene, comprises from 0.40 to 3.0 mole percent of the copolymer. In another embodiment, from 0.50 to 1.25 mole percent of the copolymer. In another embodiment, it comprises about 0.75 mole percent of the copolymer.

The copolymer used in the colorable rubber blend of the present invention is, in one embodiment, a terpolymer of isobutylene, para-methylstyrene and bromo para-methylstyrene. The copolymer occupies 20 to 100 phr (part per hundred parts rubber) of the colorable rubber blend in one embodiment. The copolymer comprises 30 to 80 phr of the colorable rubber blend in another embodiment.

General purpose rubber components

Preferably, the colorable rubber blend of the present invention contains at least one general purpose rubber. The term "general rubber" includes natural and synthetic rubbers. Suitable synthetic rubbers are homopolymers and copolymers of conjugated dienes such as polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, neoprene, polychloroprene, butyl rubber and Nitrile rubbers as well as mixtures thereof. The monetary viscosity at 100 ° C. (ML 1 + 4) of these rubbers is generally 20 to 150 (pattern viscosity is measured according to ASTM D-1646 herein).

Natural rubber for use in the present invention has a pattern viscosity at 100 ° C. (ML 1 + 4) of 30 to 120 in one embodiment and 30 to 65 in another embodiment. Natural rubber is described in detail in Subramaniam, RUBBER TECHNOLOGY 179-208 (Van Nostrand Reinhold Co. Inc., Maurice Morton, ed. 1987). The bulk of commercially available natural rubber consists of cis-1,4-polyisoprene. Generally 93 to 95% by weight of natural rubber is cis-1,4-polyisoprene.

Included within the group of natural rubbers are Malaysian rubbers such as SMR CV, SMR 5, SMR 10, SMR 20 and SMR 50 and mixtures thereof. Oil extended natural rubber can also be used in various grades. The raw rubber part may be latex or regrind rubber. Aromatic or nonpolluted cycloparaffinic oils are typically used at 10, 25 and 30% by weight of rubber.

Polyisoprene rubber may also be used, which is essentially identical in structure to natural rubber. Polyisoprene, like natural rubber, may be composed of cis-polyisoprene of all 1,4-addition structures. In one embodiment, polyisoprene could also differ from natural rubber in the relative amounts of 1,4-addition structure and 1,3-addition structure. In addition to poly (cis-1,4-isoprene), other forms of polyisoprene, namely poly-1,2 structures as obtained in combination with high purity trans-1,4 and trans-3,4 as well as three other structures, Can be used.

Polybutadiene can also be used as a general purpose rubber. The polybutadiene, addition polymerization product may be a 1,4-addition product and may have a cis-1,4 or trans-1,4 structure. Participation of a single double bond results in vinyl or 1,2-addition. Two "1,4" structures contain backbone unsaturation while two 1,2-polybutadienes contain pendant unsaturation. The pattern viscosity of the polybutadiene rubber measured at 100 ° C. (ML 1 + 4) is 40 to 70, 45 to 65 in another embodiment, and 45 to 65 in another embodiment.

Also useful as general purpose rubbers are neoprene, also known as chloroprene. The rubber, consisting of 2-chloro-1,3-butadiene units, typically consists primarily of a linear sequence of trans-1,4 structures with minor amounts of cis-1,4, 1,2 and 3,4 polymerization. The trans-1,4 and cis-1,4 structures have backbone unsaturation. 1,2 and 3,4 structures also often have pendant unsaturation. Such polymers are generally prepared by free radical emulsion polymerization.

Also, nitrile rubbers, ie random emulsion polymers of butadiene and acrylonitrile, can be used. Such polymers are well known in the art and typically the acrylonitrile ratio varies from about 15 to about 60 weight percent.

Moreover, styrene-butadiene rubber can be used as a general purpose rubber. Such copolymers are well known in the art and consist of styrene units as well as any three butadiene forms (cis-1,4, trans-1,4 and 1,2 or vinyl). Such copolymers of styrene and butadiene may be irregularly dispersed mixtures of two monomers or block copolymers. Typically, styrene-butadiene copolymers contain from 10 to 90, in another embodiment from 30 to 70% by weight of conjugated diene.

Butyl rubber is used as GPR in another embodiment of the present invention. Butyl rubber is produced by a polymerization reaction between isoolefins and conjugated diene comonomers and thus contains isoolefin-derived units and conjugated diene-derived units. The olefin copolymer feed used in connection with the catalyst and initiator system is an olefin compound, the polymerization of which is known to be initiated cationic and does not contain aromatic monomers such as para-alkylstyrene monomers. Preferably, the olefin polymerization feed used in the present invention is an olefin compound commonly used in the preparation of butyl rubber polymers. The butyl copolymer is prepared by reacting a comonomer mixture comprising at least (1) a C ₄ -C ₆ isoolefin monomer component, such as isobutylene, with (2) a multiolefin, or conjugated diene, monomer component. Isoolefins are present in one embodiment in the range of 70 to 99.5 weight percent of total comonomers, and in another embodiment in the range of 85 to 99.5 weight percent. In one embodiment the conjugated diene is present in the comonomer mixture in an amount of 30 to 0.5 weight percent, and in another embodiment 15 to 0.5 weight percent. In another embodiment, 8-0.5% by weight of the comonomer mixture is conjugated diene.

Isoolefins are C ₄ to C ₆ compounds, for example isobutylene, isobutene or 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene and 4-methyl-1 -Pentene. Multiolefins are C ₄ to C ₁₄ conjugated dienes, for example isoprene, butadiene, 2,3-dimethyl-1,3-butadiene, myrcene, 6,6-dimethyl-pulbene, hexadiene and piperylene. One embodiment of the butyl rubber polymer of the present invention is obtained by reacting 95 to 99.5 weight percent isobutylene with 0.5 to 8 weight percent isoprene and in another embodiment 0.5 to 5.0 weight percent isoprene.

In one embodiment, the butyl rubber has an isobutylene content of 95 to 99.5 weight percent. Preferred patterning viscosities of butyl rubber useful in the present invention as measured at 125 ° C. (ML 1 + 4) range from 20 to 80 in one embodiment, 25 to 55 in another embodiment and 30 to 50 in another embodiment. Range.

In one embodiment of the colorable blend, GPR accounts for 10 to 90 phr of the blend, and butyl rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, ethylene-propylene diene Rubber or mixtures thereof. In another embodiment, the colorable rubber blend will comprise 30 to 80 phr of GPR.

Filler components

Silica is preferred as filler, but other non-black fillers such as clay, talc and other inorganic fillers can be used. In addition, the remaining components of the final blend are selected on a criteria that do not interfere with the colorable properties of the elastomer. Non-black fillers are described in M. P. Wagner, RUBBER TECHNOLOGY, 86-104 (Chapman & Hall 1995).

The silica used in the colorable rubber blend of the present invention is preferably precipitated silica. Precipitated silica also accounts for 30 to 80 parts of the colorable rubber blend in one embodiment. In another embodiment, silica comprises 40 to 70 parts.

The colorable rubber compounds of the present invention are useful for making colored elastomeric products that can meet current performance criteria. These colorable compounds were prepared by replacing carbon black fillers with non-dyed inorganic fillers such as, but not limited to, molten or precipitated silica, clay, talc, calcium carbonate, aluminum oxide, titanium oxide, silicon oxide and zinc oxide. Inorganic fillers should reinforce the polymer system but should not interfere with efficient coloring. In addition, the remaining components of the colorable compound are selected on the basis of not interfering with the colorable properties of the elastomer. The cured colorable compounds of the present invention will still have the same mechanical and physical properties to meet the performance requirements of conventional black-colored tire treads.

As noted above, all components of the colorable elastomeric blend should be carefully chosen so as not to interfere with the colorability of the blend. For example, elastomers, fillers, processing aids, antidegradants and curing agents should not discolor the blend during formation of the elastomeric blend. In addition, the components should not discolor the elastomer blend by exposure to light (including UV), heat, oxygen, ozone and contaminants.

Fillers of the invention can be of any size and can, for example, typically range from about 0.0001 to about 100 microns in the tire industry. As used herein, silica can be any of those treated by a method such as solution, pyrogenicity and the like and having a predetermined surface area, including untreated precipitated silica, crystalline silica, colloidal silica, aluminum or calcium silicate, fused silica, and the like. Refers to silica or other silicic acid derivatives or silicic acid in the form or particle size of.

Silane coupling agent

One or more coupling agents are used in the elastomer blend of the present invention. In one embodiment, the coupling agent is a bifunctional organosilane coupling agent. "Organosilane coupling agent" means any silane bonded filler and / or crosslinking activator and / or silane enhancer known to those skilled in the art. The silane coupling agent used in the colorable rubber blend of the present invention is in one embodiment an organosilane-coupling agent. In one embodiment, the organosilane-coupling agent comprises from 0.1 to 20% by weight of the blend, based on the weight of the blend, and in another embodiment, from 2 to 15% by weight of the blend, based on the weight of the blend Included.

In another embodiment, the coupling agent is 2-15% by weight based on the weight of the GPR / silicone / silane masterbatch or BIMS / silicone / silane masterbatch, in another embodiment 5-10% by weight of each masterbatch. . The masterbatches are then mixed in various proportions depending on the intended use. In one embodiment, the GPR / silicone / silane masterbatch is from 30 to 70% by weight of the blend, in another embodiment from 40 to 60% by weight. In this embodiment the final weight percentage of silane in the blend is the weight of the blend. 2-15% by weight, and in another embodiment 5-10% by weight.

Organocoupling agents, or "silanes" suitable for use in the present invention may generally be described by the following formula (1).

Where

R ¹ is a vinyl, sulfur (thiol), amine, alkylthiol, alkylamine, alkylsilane, alkoxysilane, methacrylate, nitroso or halogen group;

R ² to R ⁴ are the same or different and are an alkyl, arylalkyl group, or phenyl group;

n is an integer of 1-10, Preferably it is 2-4.

In one embodiment, the silanes of the invention are at least bi-functional silanes, wherein the two residues can be used to bind or closely link the copolymer or GPR. Specific embodiments of the silane coupling agent are represented by the following Chemical Formulas 2 to 4.

Where

Formula 2 is bis (3-triethoxysilylpropyl) tetrasulfide, Formula 3 is 3-thiocyanatopropyltriethoxy silane, and Formula 4 is 3-mercaptopropyl-trimethoxy silane. Other suitable organosilane coupling agents include, but are not limited to, vinyl triethoxysilane, vinyl-tris- (beta-methoxyethoxy) silane, methacryloylpropyltrimethoxysilane, gamma-amino-propyl triethoxysilane (Commercially available as “A1100” by Witco), gamma-mercaptopropyltrimethoxysilane bis (2-triethoxysilyl-ethyl) tetrasulfide, bis (3-trimethoxysilyl-propyl) Tetrasulfide, bis (2-trimethoxysilyl-ethyl) tetrasulfide, 3-mercaptopropyl-triethoxy silane, 2-mercaptopropyl-trimethoxysilane, 2-mercaptopropyl-triethoxy silane, 3-nitropropyl-trimethoxysilane, 3-nitropropyl-triethoxysilane, 3-chloropropyl-trimethoxysilane, 3-chloropropyl-triethoxysilane, 2-chloropropyl-trimethoxysilane, 2-Chloropropyl-triethoxysilane, 3-trimethoxylsilylpropyl-N, N-dimethylthiocarba Mono tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl-benzo Thiazole tetrasulfide, 3-triethoxysilylpropyl-benzothiazole tetrasulfide, 3-trimethoxysilylpropyl-methacrylate monosulfide, 3-trimethoxysilylpropyl-methacrylate monosulfide and the like, and these It contains a mixture of. Suitable silane coupling agents are further disclosed in US Pat. Nos. 5,827,912, 5,780,535, 6,005,027, 6,136,913, and 6,121,347. In one embodiment, the silane is bis (3- (triethoxysilyl) -propyl) -tetrasulfane (commercially available as "Si 69" from Degussa), 3-thiocyanatopropyl-triethoxy silane ) ("Si 264") and 3-mercaptopropyl-trimethoxysilane ("Si 189").

Generally, polymer blends, such as those used for making tires, are crosslinked. The physical properties, performance and durability of vulcanized rubber compounds are known to be directly related to the number (crosslink density) and morphology of crosslinks formed during vulcanization (see The Post Vulcanization Stabilization for NR , WFHelt, BHTo & WWParis, Rubber). World, pp. 18-23 (1991). In general, polymer blends can be crosslinked by addition of curable molecules such as sulfur, metal oxides (ie, zinc oxides), organometallic compounds, radical initiators, and the like, followed by heating. The method can be facilitated and is often used for vulcanization of elastomer blends. Mechanisms for promoting vulcanization of natural rubber include complex reactions between hardeners, accelerators, activators and polymers. Ideally, all such available curing agents are consumed in the formation of effective crosslinks to bond the two polymer chains together and improve the overall strength of the polymer matrix. Many hardeners are known in the art and include zinc oxide, stearic acid, tetramethylthiuram disulfide (TMTD), 4,4'-dithiodimorpholine (DTDM), tetrabutylthiuram disulfide (TBTD), 2, 2'-benzothiazyl disulfide (MBTS), hexamethylene-1,6-bisthiosulfate disodium salt dihydrate (available under the trade name DURALINK HTS by Flexsys), 2- (morpholinothio) Blend of benzothiazole (MBS or MOR), 90% MOR and 10% MBTS (MOR 90) and N-oxydiethylene thiocarbamyl-N-oxydiethylene sulfonamide (OTOS) zinc 2-ethyl hexanoate ( ZEH), but is not limited to such. In addition, various vulcanization systems are known in the art ( Formula Design and Curing Charateristics of NBR Mixes for Seals , Rubber World, pp. 25-30 (1993)).

In one embodiment, it is preferred that the silica, rubber and silane are mixed vigorously before adding other compounding components such as zinc curing agents. Processing aids such as plasticizers may be present in the first mixing step but are preferably added in the subsequent mixing step after the silane is well dispersed in the GPR and copolymer.

Colorable Blend

The colorable blends of the present invention are formed by mixing or blending the various components by most of the means known in the art. In one embodiment, the colorable rubber blend of the present invention comprises, in one embodiment, from 10 to 100 phr of a copolymer (copolymer) of C ₄ to C ₇ isoolefins and para-alkylstyrene, based on the weight of the blend; Silica 10 to 100 phr; And from 0.1 to 20% by weight of silane, and from 2 to 15% by weight of silane coupling agent in another embodiment. Also in another embodiment, the colorable rubber blend of the present invention contains 10 to 90 phr of GPR, for example butyl rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene-butadiene rubber, isoprene Butadiene rubber, ethylene-propylene diene rubber neoprene, polychloroprene, nitrile rubber or blends thereof. In another embodiment, the colorable rubber blend will contain 30 to 80 phr GPR.

The copolymers used in the colorable rubber blends of the present invention are terpolymers of isobutylene, para-methylstyrene and bromo para-methylstyrene in one embodiment described above. The copolymer accounts for 20-100 phr of the colorable rubber blend in one embodiment. The copolymer comprises from 30 to 80 phr of the colorable blend in another embodiment.

In another embodiment, the blend comprises 10 to 100 phr C ₄ to C ₇ isoolefins and para-alkylstyrene, 10 to 100 phr universal rubber, 10 to 100 phr silica, based on the weight of the blend; And 0.1 to 20% by weight of coupling agent.

The blends produced according to the invention also contain other ingredients and additives conventionally used in rubber mixtures, for example effective amounts of non-discoloration and discoloration processing aids, pigments, accelerators, crosslinking and curing materials, oxidation Naphthene, aromatic or paraffin extender oils, if present, antiozonant, filler, and extender oil. Processing aids include, but are not limited to, plasticizers, tackifiers, extenders, chemical conditioners, homogenizing agents and peptizers (eg, mercaptans, petroleum and vulcanized vegetable oils, waxes, resins, rosin) and the like. Accelerators include amines, guanidines, thioureas, thiazoles, thiurams, sulfenamides, sulfenimides, thiocarbamates, xanthates and the like. Crosslinking and curing agents include sulfur, zinc oxide and fatty acids. Peroxide curing systems can also be used. Fillers include inorganic fillers such as silica and clay as described above.

The components of the colorable blend can be mixed by any standard means known to those skilled in the art, such as, for example, a BANBURY® mixer. In one embodiment, the components are mixed in three steps to mix the copolymer and silica once with one or more coupling agents (masterbatch mixing). In a separate mixing step, GPR and silica are mixed. In this embodiment, the silica coupling agent is mixed in the copolymer / silica mixture or the GPR / silica mixture. Finally, two masterbatches of copolymer / silica (silane in presence) and GPR / silica / (silane in presence) are mixed to form a blend of the present invention. One or more coupling agents may be present.

In another embodiment of the invention, the copolymer is first mixed with silica and a silane coupling agent. In a separate mixing step, GPR is mixed with silica and silane coupling agent. The two masterbatches of copolymer / silica / silane and GPR / silica / silane are then mixed together. The silane coupling agents in the two stages are the same or different and one or more coupling agents may be present.

Masterbatch mixing of BIMS / silica / silane and GPR / silica / silane can be performed in a preferred embodiment, but separated, in any order, simultaneously or at intervals of time. In the final mixing step, the BIMS / silica and GPR / silica mixture is mixed with other crosslinking or curing agents. Typical mixing times for each stage are 4-10 minutes of masterbatch mixing and 2-5 minutes of final stage mixing.

The present invention provides an improved elastomer blend comprising a copolymer of C ₄ to C ₇ isoolefins and para-alkylstyrene, silica and, optionally, one or more coupling agents. These blends have improved wear resistance, reduced cut growth, and improved adhesion during severe heat build-up conditions such as those experienced while mounting "run-flat" tires and engines for transport vehicles. , Improved properties including reduced thermal build-up and retention of mechanical properties. Substantially isoolefin (isobutylene) backbone elastomer is an important factor that imparts self-limiting thermal build-up. At low temperatures, these elastomers exhibit a high damping behavior that loses mechanical energy upon thermal formation. However, as the elastomer heats up, the damping behavior decreases and the behavior of the elastomer becomes more elastic and less dispersed.

The materials are mixed in one or several steps by conventional means known in the art. For example, the elastomer of the present invention can be processed in one, two or three steps. In one embodiment, silica and optionally silane are mixed with a copolymer of C ₄ to C ₇ isoolefins and para-alkylstyrene to form a silica / copolymer blend. The general purpose rubber is separately mixed with silica and one or more silane coupling agents to form a silica / general rubber blend, and finally the silica / copolymer blend is mixed with the silica / general rubber blend. Sulfur may be added at any stage.

In one preferred embodiment, antioxidants, anti-ozone agents and processing materials are added in one step after silica and silane have been processed with the rubber and zinc oxide is added in one step to maximize compound modulus. Thus, a processing sequence of two to three (or more) steps is preferred. Additional steps may include incremental addition of fillers and process oils.

Test Methods

Shore Hardness : DIN 53505 / ISO R 868 / ASTM 2240)

Modulus: ASTM D 412-83.

Tensile Strength: ASTM D 412-83.

Elongation at Break: ASTM D 412-83.

Pattern viscosity

Curability was measured using MDR 2000 at the indicated temperature and 0.5 ° arc. The test piece was cured at the indicated temperature, generally 150-160 ° C., for a predetermined time (minutes) corresponding to T90 + appropriate mold lag. If possible, standard ASTM tests were used to determine the physical properties of the cured compound. Stress / strain properties (tensile strength, elongation at break, modulus value, break energy) were measured at room temperature using Instron 4202 or Instron 4204. Shore A hardness was measured at room temperature using Zwick Duromatic.

Mechanical properties

The mechanical properties (G *, G ', G "and Tan δ, where G" / G' is the same as Tan δ) at 1 Hz at 0.1, 2 and 10% strain at temperatures of -20 ° C, 0 ° C and 60 ° C Pure shear specimens (double lap shear geometry) were measured using an MTS 831 mechanical spectrometer while using frequency. Temperature-dependent (-80 to 60 ° C.) mechanical properties were obtained using Rheometrics ARES. Rectangular torsion sample geometry was tested at 1 Hz and 2% strain. Values of G ″ or Tan δ measured in the range of −10 to 10 ° C. in laboratory epidemiological tests can be used as an example of tire wetland traction for carbon black-filled BR / sSBR (styrene-butadiene rubber) compounds. Temperature-dependent (-90-60 ° C.) high frequency auditory measurements were performed at the Sid Richardson Carbon Company using ethanol as the frequency and fluid medium of 1 MHz.

Monsanto Fatigue-to-Failure Test : ASTM D 4482-85.

De Mattia Cut-Growth : ASTM D 430-73.

Ozone Resistance: ASTM D 1171-83 / DIN 53509.

Example

The Y-mixing step is as follows.

EXXPRO® / silica masterbatch (with or without silane coupling agent) is used for 3-10 minutes in one embodiment, 5-8 minutes in another embodiment, 130-170 ° C. in one embodiment, In another embodiment, the mixture is mixed at 145-155 ° C. GPR / silica masterbatch with or without a silane coupling agent for 3 to 10 minutes in one embodiment, 5 to 8 minutes in another embodiment, 130 to 170 ° C. in one embodiment, another embodiment At 145 to 155 ° C. The two masterbatches are then combined with any curing agent in the final mixing operation, in one embodiment at 90-120 ° C., in another embodiment at 105-115 ° C., in one embodiment for 2-4 minutes, in another embodiment. Mix for 1.5-2.5 minutes.

Examples A through D below describe the coupling method and the final blend obtained from the method of the invention. In order to promote the silanization of the silica during mixing, the mixer should be used as a reactor as well as a device for introducing the filler and other additives into the polymer. 1 shows temperature versus time during a specific mixing cycle of EXXPRO® polymer and / or GPR and silica. For the silane coupling agent used in our study, a 145 to 165 ° C. silanization temperature and a 2 to 4 minute silanization period are required.

Samples A to C were mixed as follows. GPR and BIMS components in the mixer were set at a temperature of about 120 ° C. and a rotation speed of about 60 rpm. After 1 minute mixing, silica was added with silane and the mixing was increased to about 95 rpm. Continue for about 3 minutes or until the temperature reached 150 ° C. At this point, oil and tackifier resin were added to the blend and further mixed for 2-3 minutes until the temperature reached 150 ° C.

For sample D, Y-mixing steps were used, but GPR masterbatch and BIMS masterbatch were mixed separately for Samples A-C. The two masterbatches were then mixed in a 50:50 weight percent ratio. The temperature was maintained at about 150 ° C. for about 3 minutes of mixing. All blends are completed by introducing any curing agent through an open mill or again by mixing at a temperature of 120 ° C. or less.

Table 1 describes the various components used in the examples and corresponding trade names. Table 2 shows the effect of silane coupling agents on the curing, physical and mechanical properties of silica (ZEOPOL 8745®) filled EXXPRO 90-10® polymer and EXXPRO® filled with N220 and N660 carbon black. It is a comparison with polymers. These compounds all contain 40 phr of filler and 20 phr of oil. Curing agents used for all compounds include 4 phr stearic acid, 2 phr ZnO and 2.5 phr zinc dimethyl dithiocarbamate. Three types of silane coupling agents (in molar equivalents, ie 3 phr Si 69, 1.5 phr Si 264 and 1.1 phr Si 189) were used.

It can be seen that the use of a silane coupling agent reduces the pattern viscosity except for Si 189. Due to the strong filler-filler interaction of silica compared to carbon black, the pattern viscosity of silica filled compounds is typically greater than that filled with carbon black. The addition of silanes typically reduces the pattern viscosity. Without wishing to be bound by any particular theory, for Si 189, the high pattern viscosity is compatible with the action of silica as a crosslinking site and effectively increases the molecular weight of the EXXPRO® polymer.

Large reductions in T _c 90 due to the use of silane coupling agents are also evident from the data. Silane coupling agents increase the cure rate of silica filled EXXPRO® compounds. While not wishing to be bound by any theory, the increased cure rate may result from a small amount of coupling agent to be adsorbed onto the current silane coated silica filler.

Using Si 189 significantly increases the 100% and 300% modulus, which is compatible with the strong interaction between silica and the EXXPRO® polymer matrix. The ratio of 300% modulus to 100% modulus follows the following procedure Si 189> Si 69 >> Si 264. This is compatible with the observation that Si 189 is the most efficient to promote silica / BIMS polymer interactions and that Si 264 is the least efficient. It should be noted that the silica filled compound achieves the same or better reinforcement as the N220 or N660 carbon black filled EXXPRO® polymer.

The use of silane coupling agents also improves the mechanical performance of silica filled EXXPRO® polymers. Dynamics studies show that when silane coupling agents are used, the Tan δ value (measured at 20 Hz) increases at -20 ° C and 0 ° C, while the Tan δ value decreases at 60 ° C (measured at 20Hz). Silica filled compounds have wet grip and low rolling resistance comparable to N220 or N660 carbon black filled EXXPRO® polymers, as evidenced by similar low temperature Tan δ values and low high temperature Tan δ values. Can be expected. Without any silane, data for Tan δ and carbon black filled 50/50 EXXPRO® polymer / GPR compound as a function of temperature of silica filled EXXPRO® polymer with Si 69 are shown in Table 5 Shown in

Studies on silica filled EXXPRO® polymers indicate that the use of a silane coupling agent further enhances the dispersibility of the "high dispersion" of silica in the EXXPRO® compound. This releases the polymer "catched" into the filler network (which acts as glass at low temperatures), causing them to lose energy, leading to higher Tan δ (good wet-grips) at low temperatures. Silane coupling agents may also further facilitate the interaction between the silica and the EXXPRO® polymer. Unlike carbon black, silane induced interactions between silica and EXXPRO® polymers remain as temperature increases. This allows the silica filled compound to maintain its elasticity and low rolling resistance as the temperature increases. In contrast to the carbon black reinforced EXXPRO® polymer, the pattern viscosity of the silica filled EXXPRO® polymer decreases much less with increasing temperature (Tables 4a and 4b). This indicates that the interaction between silica and EXXPRO® polymer is much more affected at temperatures below 100 ° C.

Tables 4a and 4b show normal tire mixing of various tire sidewall performance of silica filled EXXPRO® polymer (Sample B), silica filled GPR (Sample C), and silica filled EXXPRO® polymer / GPR blend. Compare A) and silica filled EXXPRO® polymer / GPR blends via Y-mixing (Sample D).

The results in Table 4b show that the curing properties, ozone resistance, as well as fatigue cut-growth and fatigue-to-destructive resistance of silica filled EXXPRO® polymers and silica filled GPR compounds differ significantly. The compound has a faster cure rate and good fatigue but the ozone resistance is much inferior. On the other hand, silica filled EXXPRO® polymers have much better mechanical properties (high Tan δ at low temperatures and low Tan δ at high temperatures) compared to silica filled GPR compounds. If both the BIMS copolymer and the GPR component are present in the blend, the properties are generally between the silica filled copolymer and the GPR when a normal mixing cycle (both the elastomer and the filler are mixed together in one step) is applied. From Table 4b it can be observed that the mixing procedure has a significant effect on the performance of the silica filled copolymer / GPR blend. Compared to the compound derived from the normal mixing cycle (Sample A), the Y-mixed compound (Sample D) has a much better Monsanto fatigue-to-destruction and de matia cut-groth resistance. Two-step Y-mixing also leads to a much better ozone resistance of the compound. This is likely to be regarded as the observed improved fatigue and ozone resistance. The mixing procedure also has a significant impact on the distribution of silica fillers in different elastomeric phases.

Colorable elastomer blends of the present invention exhibit improved hysteretic properties, traction, thermal stability and retention of properties upon aging with known colorable elastomers. This produces a colorable rubber composition having sufficient properties to act as a reinforcing member of a car tire. Colorable rubber will allow manufacturers to produce tires with improved product appearance.

More specifically, silica filled BIMS has good potential for developing tires with good sidewall appearance in any of white, black or any color. Tires made with silica filled BIMS polymers as sidewalls will also typically have better mechanical performance than those made with all carbon black filled GPR compounds. In general, when used in tire compounds, BIMS is blended with GPR to achieve high “raw” (pre-cure) viscosity for easier tire build and good compound-compound adhesion during vulcanization.

Elastomeric blends of the present invention can be used in a variety of applications, in particular pneumatic tire components (eg tire sidewalls), hoses, belts, solid tires, shoe components, rollers used in graphics applications, vibratory separating devices, pharmaceutical devices, It is useful in adhesives, sealants, protective coatings and bladder for fluid retention and curing purposes.

While certain representative embodiments and detailed descriptions have been presented for the purpose of illustrating the invention, those skilled in the art will clearly appreciate that various changes can be made in the methods and products disclosed herein without departing from the spirit of the invention as defined in the appended claims. I will understand.

These documents are incorporated herein by reference within the jurisdiction which allows the introduction of all priorities. In addition, all documents cited herein, such as those related to test procedures, are hereby incorporated by reference in their entirety for all jurisdictions that allow such introduction.

Ingredients Used in the Examples compound Explanation Salesman BUDENE 1207 Cis-polybutidaene Goodyear Chemical Company (Akron, Ohio, USA) DHT-4A-2 Magnesium aluminum hydroxide carbonate Kyowa Chemical Ind., Co. KORESIN (registered trademark) Butylphenol Acetylene Resin BASF (Belgium) MBTS 2,2'-dibenzothiazyldisulfide Flexsys (Belgium) N220 Carbon black, medium blister wear furnace Degussa (Germany) SMR CV 50 Standard Malaysian natural rubber Safic N660 Carbon Black, General Purpose Furnace Degussa (Germany) PEG Polyethylene glycol Union Carbide BNLX (Belgium) SILANE 69, or Si 69 Bis- (3- (triethoxysilyl) -propyl) -tetrasulfane Degussa (Germany) Si 189 Gamma-mercapto-propyltrimethoxy silane Witco (Europe) S.A. (Germany) Si 264 3-thiocyanatepropyl-triethoxysilane Degussa (Germany) STRUCTOL (registered trademark) Blends of Aliphatic-Aromatic-Naphthene Resins Schill & Seilacher (Germany) VN3 Precipitated amorphous silica Degussa-huls VULTAC® 5 Alkylphenol Disulfide Sovereign Chemical Co. (Akron, Ohio, USA) WINGTACK (registered trademark) EXTRA Hydrocarbon resin Goodyear Chemical Company (Akron, Ohio, USA) ZEOPOL (registered trademark) 8745 Precipitated amorphous silica, SG 2.0, surface area 165-195, pH 6.4 Huber Corporation (Haber de Grace, USA)

Pattern Viscosity ML (1 + 4) Measured at Various Temperatures of Components Pattern viscosity ML (1 + 4) No fillers N220 N660 ZEOPOL (registered trademark) + Si69 VN3 + Si 69 40 ℃ 57 76 71 79 80 60 ℃ 53 69 65 76 76 100 ℃ 33 50 45 71.5 68

Composition of Samples A to D Masterbatch A B C D Natural Rubber SMR CV 50 10 - 20 10 BUDENE 1207 40 - 80 40 EXXPRO (registered trademark) 90-10 50 100 - 50 ZEOPOL (registered trademark) 8745 40 40 40 40 Silane 69 1.5 1.5 1.5 1.5 Paraffin inorganic oil 20 20 20 20 Polyethylene glycol One One One One KORESIN (registered trademark) 3 3 3 3 WINGTACK (registered trademark) EXTRA 3 3 3 3 STRUKTOL® 40 MS 3 3 3 3 complete DHT-4A-2 0.5 0.5 0.5 0.5 sulfur 0.3 0.3 0.3 0.3 VULTAC® 5 0.5 0.5 0.5 0.5 Stearic acid One One One One Zinc oxide One One One One MBTS 1.2 1.2 1.2 1.2

Properties of Samples A through D Property A B C D Pattern viscosity, ML (1 + 4) 100 degrees Celsius 53.0 55.1 52.5 40.8 Rheometer, MDR (Arc. 0.5 °, 180 ° C) ML (dN.m) 1.79 1.79 1.95 1.34 MH (dN.m) 6.07 5.96 6.80 5.52 T _s 2, Burn (min) 3.76 6.36 2.53 4.04 T _c 90, hardening (min) 9.5 12.6 6.6 9.3 Mechanical Properties (DMTA): TAN δ (20 Hz / 0 ° C) 0.56 1.00 0.24 0.56 TAN δ (20 Hz / 60 ° C) 0.19 0.15 0.22 0.17 Physical property: Shore hardness A (3 seconds) 35.9 39.5 35.8 33.5 Modulus 100% (MPa) 0.9 1.2 0.6 0.8 Modulus 300% (MPa) 3.5 5.3 1.7 2.5 Modulus 300% / Modulus 100% 3.9 4.4 2.8 3.1 Tensile Strength (MPa) 5.9 8.0 4.9 5.4 Elongation at Break (%) 450 415 595 550 Monsanto Fatigue-to-Destructive Testing: 140% Elongation (kilo-cycle) 25.6 12.4 119.8 57.3 De Matthias Cut-Gross (mm): 10 KC 7 5.5 2 2.5 30 KC 16 12 2 3 50 KC 22.5 17 2.5 3.5 100 KC 25 25 4 4 250 KC 25 25 6.5 6 500 KC 25 25 10 7.5 1000 KC 25 25 12.5 8.5 Ozone Resistance: 200 pphm / 50% RH / 40 ℃ / 120% Elongation color black black Brown black Time to first crack 16 > 50 0.5 > 50 Time to destruction 20 > 50 12 > 50

Claims (43)

a) a copolymer of C ₄ to C ₇ isoolefins and para-alkylstyrene with silica, b) a general purpose rubber is mixed separately with silica, wherein at least one silane coupling agent is added to the silica / copolymer or silica / general purpose Mixing with at least one of the rubber mixtures and c) mixing the silica / copolymer mixture with the silica / general rubber mixture to form a blend. The method of claim 1, The general-purpose rubber is a natural rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, neoprene, polychloroprene, butyl rubber, nitrile rubber and blends thereof Method selected from the group consisting of: The method of claim 2, Wherein said general purpose rubber is selected from the group consisting of natural rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, and blends thereof. The method of claim 3, wherein Said general purpose rubber selected from the group consisting of natural rubber, polybutadiene, styrene-butadiene rubber and blends thereof. The method of claim 1, C ₄ to C ₇ isoolefin isobutylene. The method of claim 5, Wherein said para-alkylstyrene is para-methylstyrene. The method of claim 1, Wherein said copolymer is a terpolymer of isobutylene, para-methylstyrene and bromo para-methylstyrene. The method of claim 1, Wherein said blend is colorable. The method of claim 1, Wherein said blend is substantially free of carbon black and antioxidants. The method of claim 1, The blend is based on the weight of the blend: a) 10 to 100 phr of copolymers of C ₄ to C ₇ isoolefins and para-alkylstyrene, b) 10 to 100 phr of general purpose rubber, c) 10 to 100 phr of silica, and d) 0.1 to 20% by weight coupling agent. The method of claim 10, The general-purpose rubber is a natural rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, neoprene, polychloroprene, butyl rubber, nitrile rubber and blends thereof Method selected from the group consisting of: The method of claim 10, Wherein said copolymer is a terpolymer of isobutylene, para-methylstyrene and bromo para-methylstyrene. The method of claim 12, Wherein said blend comprises 20 to 100 phr terpolymers of isobutylene, para-methylstyrene and bromo para-methylstyrene. The method of claim 10, Wherein the silica is precipitated silica. The method of claim 14, Wherein said blend comprises 30 to 80 phr of precipitated silica. The method of claim 10, The coupling agent is an organosilane coupling agent. The method of claim 16, The blend comprises 2 to 15% by weight of organosilane-coupling agent, based on its weight. The method of claim 1, The coupling agent is a group consisting of bis- (3- (triethoxysilyl) -propyl) -tetrasulfane, gamma-mercaptopropyltrimethoxysilane, 3-thiocyanatopropyl-trimethoxy silane and blends thereof The organosilane coupling agent selected from. Blends prepared by the method of claim 1. a) mixing a general purpose rubber with silica and one or more coupling agents to form a silica / general rubber mixture and b) mixing the silica / general rubber mixture with a copolymer of C ₄ to C ₇ isoolefins and para-alkylstyrene Forming a blend by forming a blend. The method of claim 20, Varying the mixing time of the silica / general rubber blend with the copolymer of C ₄ to C ₇ isoolefins and para-alkylstyrene to control silica dispersion between the universal rubber and the copolymer in an elastomer blend. The method of claim 20, The general-purpose rubber is a natural rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, neoprene, polychloroprene, butyl rubber, nitrile rubber and blends thereof Method selected from the group consisting of: The method of claim 22, Wherein said general purpose rubber is selected from the group consisting of natural rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber and blends thereof. The method of claim 23, Said general purpose rubber selected from the group consisting of natural rubber, polybutadiene, styrene-butadiene rubber and blends thereof. The method of claim 20, Wherein said C ₄ to C ₇ isoolefin is isobutylene. The method of claim 25, Wherein said para-alkylstyrene is para-methylstyrene. The method of claim 20, Wherein said copolymer is a terpolymer of isobutylene, para-methylstyrene and bromo para-methylstyrene. The method of claim 20, Wherein said blend is colorable. The method of claim 20, Wherein said blend is substantially free of carbon black and antioxidants. Elastomer blends prepared by the method of claim 20. The method of claim 1, Further comprising adding sulfur to step b), step c) or both steps. a) mixing a copolymer of C ₄ to C ₇ isoolefins with para-alkylstyrene with silica and one or more coupling agents to form a silica / copolymer mixture, b) separating the universal rubber from silica and one or more coupling agents Mixing to form a silica / general rubber mixture, and c) mixing the silica / copolymer mixture with the silica / general rubber mixture to form a blend. The method of claim 32, The general-purpose rubber may be natural rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, neoprene, polychloroprene, butyl rubber, nitrile rubber and blends thereof Method selected from the group consisting of: The method of claim 33, wherein Wherein said general purpose rubber is selected from the group consisting of natural rubber, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, and blends thereof. The method of claim 34, wherein Said general purpose rubber selected from the group consisting of natural rubber, polybutadiene, styrene-butadiene rubber and blends thereof. The method of claim 32, C ₄ to C ₇ isoolefin isobutylene. The method of claim 36, Wherein said para-alkylstyrene is para-methylstyrene. The method of claim 32, Wherein said copolymer is a terpolymer of isobutylene, para-methylstyrene and bromo para-methylstyrene. The method of claim 32, Wherein said blend is colorable. The method of claim 32, Wherein said blend is substantially free of carbon black and antioxidants. Isoolefins having 4 to 7 carbon atoms and about 0.5 to about 20% by weight of para-alkylstyrene, wherein about 0.2 to about 3 mole percent of the methyl groups present on the benzene ring of the para-alkylstyrene comprise halogen atoms Isoolefin / para-alkylstyrene copolymers; General purpose rubbers selected from the group consisting of polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-butadiene rubber, isoprene-butadiene rubber, neoprene, polychloroprene, butyl rubber, nitrile rubber and blends thereof; Silica fillers; And Blend comprising at least one silane coupling agent of formula Formula 1 Where R ¹ is a vinyl, sulfur, amine, alkylthiol, alkylamine, alkylsilane, alkoxysilane, methacrylate, nitroso or halogen group; R ² to R ⁴ are the same or different and are an alkyl, arylalkyl group or phenyl group; n is an integer from 1 to 10. 42. The method of claim 41 wherein Blend wherein C ₄ to C ₇ isoolefin is isobutylene. The method of claim 42, The silane coupling agent is bis (3-triethoxysilylpropyl) tetrasulfide, 3-thiocyanatopropyltriethoxy silane, 3-mercaptopropyl-trimethoxy silane, vinyl triethoxysilane, vinyl-tris- ( Beta-methoxyethoxy) silane, methacryloylpropyltrimethoxysilane, gamma-amino-propyl triethoxysilane, gamma-mercaptopropyltrimethoxysilane bis (2-triethoxysilyl-ethyl) tetra Sulfide, bis (3-trimethoxysilyl-propyl) tetrasulfide, bis (2-trimethoxysilyl-ethyl) tetrasulfide, 3-mercaptopropyl-triethoxy silane, 2-mercaptopropyl-trimethoxy Silane, 2-mercaptopropyl-triethoxy silane, 3-nitropropyl-trimethoxysilane, 3-nitropropyl-triethoxysilane, 3-chloropropyl-trimethoxysilane, 3-chloropropyl-trie Methoxysilane, 2-chloropropyl-trimethoxysilane, 2-chloropropyl-triethoxysilane , 3-trimethoxylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilyl-N, N- Dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl-benzothiazole tetrasulfide, 3-triethoxysilylpropyl-benzothiazole tetrasulfide, 3-trimethoxysilylpropyl-methacrylate monosulfide, 3 A blend selected from the group consisting of -trimethoxysilylpropyl-methacrylate monosulfide and mixtures thereof.