Scandium catalyst system and method for producing ethylene / butadiene copolymer

Abstract

Scandium catalyst systems and methods of producing ethylene / butadiene copolymers. A process for producing an ethylene-butadiene copolymer includes copolymerizing butadiene with ethylene in the presence of a catalyst system. The catalyst system includes tris [(trimethylsilyl) methyl] scandium and an aluminum-containing activator.

Description

Technical Field

[0001] The present invention relates to a process for producing an ethylene-butadiene copolymer and a process for producing an ethylene-butadiene copolymer. Background Art

[0002] The catalysts currently used to prepare cis-polybutadiene do not incorporate significant amounts of ethylene.

[0003] It would be desirable to develop new systems and processes for producing ethylene / butadiene copolymers. Summary of the invention

[0004] In some embodiments, a method for producing an ethylene-butadiene copolymer is disclosed. The method includes copolymerizing butadiene with ethylene in the presence of a catalyst system. The catalyst system comprises tris[(trimethylsilyl)methyl]scandium; and an aluminum-containing activator. The catalyst system may further include a borate co-activator. In some embodiments, the borate co-activator comprises tetrakis(3,5-bis(trifluoromethyl)phenyl)borate and / or tetrakis(pentafluorophenyl)borate. The aluminum-containing activator may include an aluminoxane activator. In some embodiments, the aluminoxane activator comprises a modified aluminoxane activator. The aluminoxane activator may include a methylaluminoxane activator. In some embodiments, the methylaluminoxane activator is a modified methylaluminoxane activator. The aluminum-containing activator may include MMAO-12. In some embodiments, the aluminum-containing activator comprises a trialkylaluminum activator; and the catalyst system further comprises a borate co-activator. The trialkylaluminum activator may include triisobutylaluminum. In some embodiments, the molar ratio of the aluminum-containing activator to tris[(trimethylsilyl)methyl]scandium is from about 20 to about 1000, from about 50 to about 500, or from about 75 to about 200. The method may further include quenching the copolymerized reaction product. In some embodiments, the method further includes drying the quenched reaction product. The reaction product may be quenched with a quenching composition containing isopropanol and butylated hydroxytoluene.

[0005] In other embodiments, a method for producing ethylene-butadiene copolymers is disclosed. The method includes providing a first composition containing butadiene and ethylene to a reactor; providing a second composition containing tris[(trimethylsilyl)methyl]scandium and a first aliquot of an aluminum-containing activator to the reactor; and copolymerizing the butadiene and ethylene. The first composition may further include a second aliquot of an aluminum-containing activator. In some embodiments, the method further includes quenching the copolymerized reaction product; and drying the quenched reaction product. The aluminum-containing activator may include a modified aluminoxane activator; or the aluminum-containing activator may include a trialkylaluminum activator, and at least one of the first composition and the second composition may further include a borate co-activator.

[0006] The present invention discloses the following embodiments:

[0007] 1. A method for producing an ethylene-butadiene copolymer, the method comprising:

[0008] butadiene is copolymerized with ethylene in the presence of a catalyst system comprising:

[0009] tris[(trimethylsilyl)methyl]scandium; and

[0010] Contains aluminum activator.

[0011] 2. The method according to embodiment 1, wherein the catalyst system further comprises:

[0012] Borate co-activator.

[0013] 3. The method of embodiment 2, wherein the borate co-activator comprises tetrakis(3,5-bis(trifluoromethyl)phenyl)borate and / or tetrakis(pentafluorophenyl)borate.

[0014] 4. The method according to embodiment 1, wherein the aluminum-containing activator is an aluminoxane activator.

[0015] 5. The method according to embodiment 4, wherein the aluminoxane activator is a modified aluminoxane activator.

[0016] 6. The method of embodiment 4, wherein the aluminoxane activator is a methylaluminoxane activator.

[0017] 7. The method according to embodiment 6, wherein the methylaluminoxane activator is a modified methylaluminoxane activator.

[0018] 8. The method of embodiment 1, wherein the aluminum-containing activator comprises MMAO-12.

[0019] 9. The method of embodiment 1, wherein the aluminum-containing activator comprises a trialkylaluminum activator; and wherein the catalyst system further comprises:

[0020] Borate co-activator.

[0021] 10. The method of embodiment 9, wherein the trialkylaluminum activator comprises triisobutylaluminum.

[0022] 11. The method of embodiment 9, wherein the borate co-activator comprises tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.

[0023] 12. The method of embodiment 9, wherein the borate co-activator comprises tetrakis(pentafluorophenyl)borate.

[0024] 13. The method of embodiment 1, wherein the molar ratio of the aluminum-containing activator to tris[(trimethylsilyl)methyl]scandium is from about 20 to about 1000.

[0025] 14. The method according to embodiment 1 further comprises:

[0026] The copolymerized reaction product is quenched.

[0027] 15. The method according to embodiment 14, further comprising:

[0028] The quenched reaction product was dried.

[0029] 16. The method of embodiment 14, wherein the reaction product is quenched with a quenching composition comprising isopropanol and butylated hydroxytoluene.

[0030] 17. A method for producing an ethylene-butadiene copolymer, the method comprising:

[0031] providing a first composition comprising butadiene and ethylene to a reactor;

[0032] providing a second composition comprising tris[(trimethylsilyl)methyl]scandium and a first aliquot of an aluminum-containing activator to a reactor; and

[0033] Copolymerize butadiene with ethylene.

[0034] 18. The method of embodiment 17, wherein the first composition further comprises a second aliquot of an aluminum-containing activator.

[0035] 19. The method according to embodiment 17, further comprising:

[0036] quenching the copolymerization reaction product; and

[0037] The quenched reaction product is dried.

[0038] 20. The method according to embodiment 17, wherein

[0039] (a) the aluminum-containing activator comprises a modified aluminoxane activator; or

[0040] (b) the aluminum-containing activator comprises a trialkylaluminum activator, and at least one of the first composition and the second composition further comprises a borate co-activator.

[0041] These and other non-limiting aspects and / or objects of the present disclosure are more particularly described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The following is a brief description of the drawings, which are presented to illustrate exemplary embodiments disclosed herein and not to limit the same.

[0043] Figure 1 is a flow chart illustrating a non-limiting example of a method of producing a catalyst composition according to some embodiments of the present disclosure.

[0044] Figure 2 is a flow chart illustrating a non-limiting example of a method of producing an ethylene-butadiene copolymer according to some embodiments of the present disclosure.

[0045] Figure 3 is a partial side view of a non-limiting example of a tire according to some embodiments of the present disclosure.

[0046] Figure 4 is a flow chart illustrating a non-limiting example of a method of forming an article according to some embodiments of the present disclosure. Specific implementation plan

[0047] The present disclosure may be understood more readily by reference to the following detailed description of contemplated embodiments and the accompanying drawings contained herein.In the following specification and in the claims that follow, reference will be made to a number of terms which shall be defined to have the following meanings.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art are generally understood. In the event of a conflict, this document (including definitions) shall prevail. Methods and materials are described below, although similar or equivalent methods and materials may be used in the practice or testing of the present disclosure. All publications, patent applications, patents and other references mentioned herein are incorporated herein by reference in their entirety. The materials, methods and products disclosed herein are exemplary only and are not intended to be limiting.

[0049] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0050] The term "comprising" as used in the specification and claims may include the embodiments of "consisting of" and "consisting essentially of." As used herein, the terms "comprising," "including," "having," "having," "may," "containing," and variations thereof are intended to be open transition phrases that require the presence of specified ingredients / steps and allow for the presence of other ingredients / steps. However, such descriptions should be interpreted as also describing compositions, mixtures, or methods as "consisting of" and "consisting essentially of" the listed ingredients / steps, which only allow for the presence of the specified ingredients / steps, and any impurities that may result therefrom, and exclude other ingredients / steps.

[0051] Unless otherwise indicated, the numerical values ​​in the specification should be understood to include the same value when reduced to the same number of significant figures and values ​​that differ from the specified value by less than the experimental error of ordinary measurement techniques used to determine the particular value.

[0052] All ranges disclosed herein are inclusive of the recited endpoints and are independently combinable (e.g., the range "2 to 10" includes the endpoints 2 and 10 and all intermediate values). The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact ranges or values; they are imprecise enough to include values ​​approximating these ranges and / or values.

[0053] As used herein, approximations can be used to modify any quantitative expression, which may vary without causing a change in the basic function to which it relates. Therefore, the value modified by one or more terms such as "approximately" and "substantially" may not be limited to the specified exact value in some cases. The modifier "approximately" should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the phrase "about 2 to about 4" also discloses a range of "2 to 4". The term "approximately" may refer to plus or minus 10% of the numerical value shown. For example, "about 10%" may refer to a range of 9% to 11%, and "about 1" may refer to 0.9-1.1.

[0054] For the enumeration of numerical ranges herein, each intermediate number with the same precision is expressly contemplated. For example, for the range of 6-9, in addition to 6 and 9, the numbers 7 and 8 are also contemplated, and for the range of 6.0-7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 and 7.0 are expressly contemplated.

[0055] The present disclosure relates to a process for producing ethylene-butadiene copolymers, catalyst compositions for use in the production process, and articles formed from the compositions including the copolymers.

[0056] It has unexpectedly been discovered that the catalyst composition, when exposed to a mixture of butadiene and ethylene, is capable of producing copolymers containing up to 6 mole percent ethylene.

[0057] The scandium catalyst system is a simpler and potentially cheaper variant of the catalysts reported in the literature.

[0058] Figure 1 1 is a flow chart illustrating a non-limiting example of a method 100 for producing a catalyst composition according to some embodiments of the present disclosure. The method 100 includes dissolving tris[(trimethylsilyl)methyl]scandium in a solvent 100.

[0059] An aluminum-containing activator and an optional borate co-activator are added 120. The solvent may be a hydrocarbon solvent. In some embodiments, the solvent includes one or more aromatic, paraffinic and / or cycloparaffinic compounds. The solvent may contain 4 to 10 carbon atoms. Non-limiting examples include butane, pentane, isooctane, cyclohexane, n-hexane, benzene, toluene, xylene, ethylbenzene and diethylbenzene. A mixture of two or more hydrocarbon solvents may also be used.

[0060] The aluminum-containing activator may be an aluminoxane activator. The aluminoxane activator may be an alkyl aluminoxane activator, such as a methyl aluminoxane activator.

[0061] The aluminoxane activator may be a modified aluminoxane activator, such as a modified methyl aluminoxane activator.

[0062] In some embodiments, the methylaluminoxane activator is modified by replacing a portion of the methyl groups with a linear or branched alkyl group having 3 to 10 carbon atoms. In some embodiments, 40 mol % or less (e.g., 5 to 35 mol %) of the alkyl group may be substituted.

[0063] Non-limiting examples of modified methylaluminoxane activators include MMAO-12, MMAO-3a, and MMAO-7.

[0064] The aluminum-containing activator may comprise at least one organoaluminum compound, such as a triorganoaluminum compound. The triorganoaluminum compound may be a trialkylaluminum compound.

[0065] Non-limiting examples of aluminum-containing compounds include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyldiphenylaluminum, ethyldi-p-tolylaluminum, ethyldibenzylaluminum, diethylphenylaluminum, diethyl-p-tolylaluminum, and diethylbenzylaluminum.

[0066] The molar ratio of the aluminum-containing activator to tris[(trimethylsilyl)methyl]scandium may be from about 20 to about 1000, from about 50 to about 500, or from about 75 to about 200.

[0067] The borate co-activator may include one or more of the following: trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, tri(tert-butyl)ammonium tetraphenylborate, N,N-dimethylanilinium tetraphenylborate, N,N-diethylanilinium tetraphenylborate, N,N-dimethylanilinium tetrakis-(3,5-bis(trifluoromethyl)phenyl)borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetraphenylborate, trimethylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tri(sec-butyl)ammonium tetrakis(pentafluorophenyl)borate , N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetrakis(pentafluorophenyl)borate, trimethylammonium tetrakis-(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylanilinium tetrakis-(2,3,4,6-tetrafluorophenyl)borate; di-(isopropyl)ammonium tetrakis(pentafluorophenyl)borate, dicyclohexylammonium tetrakis(pentafluorophenyl)borate; triphenylphosphine tetrakis(pentafluorophenyl)borate, tri(o-tolyl)phosphine tetrakis(pentafluorophenyl)borate, tri(2,6-dimethylphenyl)phosphine tetrakis(pentafluorophenyl)borate; and / or N,N-dimethylanilinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.

[0068] The molar ratio of aluminum-containing activator to borate co-activator may be from about 20 to about 1000, from about 50 to about 500, or from about 75 to about 200.

[0069] The co-activator may be used stoichiometrically relative to the primary metal catalyst. The molar ratio of the borate co-activator to tris[(trimethylsilyl)methyl]scandium may be about 1.

[0070] Figure 2 2 is a flow chart illustrating a non-limiting example of a method 201 for producing an ethylene-butadiene copolymer according to some embodiments of the present disclosure. The method 201 includes preparing a catalyst composition 200, copolymerizing ethylene and butadiene in the presence of the catalyst composition 230, quenching 240, and drying 250. The ethylene-butadiene copolymer may contain about 1 mol% to about 20 mol%, about 1 mol% to about 10 mol%, or about 1 mol% to about 7 mol% ethylene.

[0071] Optionally, catalyst composition 200 is prepared as described above for method 100. The catalyst composition includes tris[(trimethylsilyl)methyl]scandium, an aluminum-containing activator, and optionally a borate co-activator.

[0072] The ethylene and butadiene reacted during copolymerization 230 may be provided to the copolymerization reactor before the catalyst composition, simultaneously with the catalyst composition, and / or after the catalyst composition.

[0073] Copolymerization 230 may include providing ethylene to a polymerization vessel containing butadiene. Ethylene may be provided by flushing a solution containing butadiene in a solvent with ethylene. Ethylene gas may be provided to saturate the butadiene. A catalyst composition is provided to the polymerization vessel. The vessel may be heated to a temperature of about 30° C. to about 150° C., about 30° C. to about 100° C., or about 40° C. to about 90° C. for a time of about 15 minutes to about 36 hours, about 20 minutes to about 12 hours, or about 20 minutes to about 3 hours.

[0074] Quenching 240 includes providing a quenching composition to the polymerization vessel. The quenching composition may contain an acidic proton source and / or a proton quencher. An antioxidant may be included in the quenching composition and / or provided to the polymerization vessel simultaneously or subsequently. In some embodiments, the quenching composition contains isopropanol and butylated hydroxytoluene (BHT). In some embodiments, an excess of isopropanol or other protic solvent is added together with 0.1phr to 1.0phr, 0.25phr to 0.75phr, or about 0.5phr of a stabilizer (e.g., BHT).

[0075] Drying 250 evaporates the solvent and may be passive or active.

[0076] Also disclosed are articles produced using the ethylene / butadiene copolymers. For example, the ethylene / butadiene copolymers can be used in the production of tires.

[0077] The rubber composition can be incorporated into various rubber components of a tire. For example, the rubber component can be a tread (including a tread cap and a tread base), a sidewall, an apex, a chafer, a sidewall insert, a wirecoat, or an innerliner. In one embodiment, the component is a tread.

[0078] The pneumatic tire can be a racing tire, a passenger car tire, an aircraft tire, an agricultural tire, a bulldozer tire, an off-road tire, a truck tire, etc. In one embodiment, the tire is a passenger car or truck tire. The tire can also be a radial tire or a bias tire.

[0079] The rubber composition may also be used in other products including, but not limited to, non-pneumatic tires, belts, hoses, shoes, air springs, engine mounts, and the like.

[0080] The rubber composition may optionally include one or more rubbers or elastomers containing ethylenic unsaturation in addition to the ethylene-butadiene copolymer. The phrase "rubber or elastomer containing ethylenic unsaturation" or "diene-based elastomer" is intended to include natural rubber and its various original and recycled forms, as well as various synthetic rubbers. In the specification, unless otherwise specified, the terms "rubber" and "elastomer" are used interchangeably. The terms "rubber composition", "compounded rubber" and "rubber compound" are used interchangeably to refer to rubber that has been blended or mixed with various ingredients and materials, and such terms are well known to technicians in the field of rubber mixing or rubber compounding. Representative synthetic polymers are butadiene and its homologues and derivatives, such as homopolymerization products of methylbutadiene, dimethylbutadiene and pentadiene, and copolymers, such as copolymers formed by butadiene or its homologues or derivatives and other unsaturated monomers. Among other unsaturated monomers are acetylenes such as vinyl acetylene; olefins such as isobutylene, which copolymerizes with isoprene to form butyl rubber; vinyl compounds such as acrylic acid, acrylonitrile (which polymerizes with butadiene to form NBR), methacrylic acid, and styrene (the latter compound polymerizes with butadiene to form SBR), as well as vinyl esters and various unsaturated aldehydes, ketones, and ethers, such as acrolein, methyl isopropenyl ketone, and vinyl ethyl ether. Specific examples of synthetic rubbers include chloroprene rubber (polychloroprene), polybutadiene (including cis-1,4-polybutadiene), polyisoprene (including cis-1,4-polyisoprene), butyl rubber, halogenated butyl rubber such as chlorobutyl rubber or bromobutyl rubber, styrene / isoprene / butadiene rubber, copolymers of 1,3-butadiene or isoprene with monomers such as styrene, acrylonitrile and methyl methacrylate, and ethylene / propylene terpolymers, also known as ethylene / propylene / diene monomers (EPDM), and in particular ethylene / propylene / dicyclopentadiene terpolymers. Additional examples of useful rubbers include alkoxy-silyl end-functionalized solution polymerized polymers (SBR, PBR, IBR and SIBR), silicon-coupled and tin-coupled star-branched polymers. Preferred rubbers or elastomers are polyisoprene (natural or synthetic), polybutadiene and SBR.

[0081] In some embodiments, at least one additional rubber is preferably at least two diene-based rubbers. For example, combinations of two or more rubbers are preferred, such as cis-1,4-polyisoprene rubber (natural or synthetic, but natural is preferred), 3,4-polyisoprene rubber, styrene / isoprene / butadiene rubber, emulsion and solution polymerization derived styrene / butadiene rubber, cis-1,4-polybutadiene rubber, and butadiene / acrylonitrile copolymers prepared by emulsion polymerization.

[0082] In some embodiments, an emulsion polymerization derived styrene / butadiene (E-SBR) having a relatively conventional styrene content of about 20 to about 28% bound styrene may be used, or for some applications, an E-SBR having a moderate to relatively high bound styrene content, i.e., about 30 to about 45% bound styrene content.

[0083] E-SBR prepared by emulsion polymerization refers to styrene and 1,3-butadiene copolymerized as an aqueous emulsion. This is well known to those skilled in the art. The bound styrene content can vary, for example, from about 5% to about 50%. In one aspect, E-SBR can also contain acrylonitrile to form a terpolymer rubber (in the form of E-SBAR), the amount of bound acrylonitrile in the terpolymer being, for example, from about 2 to about 30 weight percent.

[0084] Styrene / butadiene / acrylonitrile copolymer rubbers prepared by emulsion polymerization containing from about 2 to about 40 weight percent bound acrylonitrile in the copolymer are also considered to be diene-based rubbers.

[0085] Solution polymerization prepared SBR (S-SBR) typically has a bound styrene content in the range of about 5 to about 50%, preferably about 9 to about 36%. S-SBR can be conveniently prepared, for example, by organolithium catalysis in the presence of an organic hydrocarbon solvent.

[0086] In one embodiment, cis 1,4-polybutadiene rubber (BR) may be used. Such BR may be prepared, for example, by organic solution polymerization of 1,3-butadiene. BR may conveniently be characterized, for example, as having a cis 1,4-content of at least 90%.

[0087] Cis 1,4-polyisoprene and cis 1,4-polyisoprene natural rubber are well known to those skilled in the rubber art.

[0088] As used herein and in accordance with conventional practice, the term "phr" means "parts by weight of the respective material per 100 parts by weight of rubber or elastomer."

[0089] The rubber composition may also include up to 70phr of processing oil. Processing oil may be included in the rubber composition as a filler oil commonly used for filling elastomers. Processing oil may also be included in the rubber composition by directly adding oil during rubber compounding. The processing oil used may include both the filler oil present in the elastomer and the process oil added during compounding. Suitable process oils include various oils known in the art, including aromatic oils, paraffinic oils, naphthenic oils, vegetable oils and low PCA oils, such as MES, TDAE, SRAE and heavy naphthenic oils. Suitable low PCA oils include those having a polycyclic aromatic hydrocarbon content of less than 3% by weight as determined by the IP346 method. The procedure of the IP346 method can be found in Standard Methods for Analysis & Testing of Petroleum and Related Products and British Standard 2000 Parts, the 62nd edition, published by the Institute of Petroleum, United Kingdom.

[0090] The rubber composition may include from about 10 to about 150 phr of silica. In another embodiment, 20 to 80 phr of silica may be used.

[0091] Common siliceous pigments that can be used in rubber compounds include conventional pyrolytic and precipitated siliceous pigments (silicon dioxide). In one embodiment, precipitated silica is used. The conventional siliceous pigment used is precipitated silica, such as those obtained by acidification of soluble silicates, such as sodium silicate.

[0092] Such conventional silicas may be characterized, for example, by having a BET (Brunauer-Emmett-Teller) surface area as measured using nitrogen. In one embodiment, the BET surface area may be in the range of about 40 to about 600 square meters per gram. In another embodiment, the BET surface area may be in the range of about 80 to about 300 square meters per gram. The BET method for measuring surface area is described in the Journal of the American Chemical Society, Vol. 60, p. 304 (1930).

[0093] Conventional silicas may also be characterized as having a dibutyl phthalate (DBP) absorption value in the range of about 100 to about 400, or about 150 to about 300.

[0094] Conventional silica can be expected to have an average ultimate particle size, for example, in the range of 0.01 to 0.05 microns as determined by electron microscopy, although the silica particles can be smaller or possibly larger in size.

[0095] Various commercially available silicas may be used, such as, by way of example only and not limitation, silicas commercially available from PPG Industries under the Hi-Sil trademark and designations 210, 243, etc.; silicas available from Rhodia under the designations Z1165MP and Z165GR, and silicas available from Degussa AG under the designations VN2 and VN3, etc., etc.

[0096] Can use common carbon black as conventional filler with the amount of 10 to 150phr.In another embodiment, can use 20 to 80phr carbon black.Representative example of such carbon black comprises N110, N121, N134, N220, N231, N234, N242, N293, N299, N315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 and N991.These carbon blacks have iodine absorption of 9 to 145g / kg and 34 to 150cm 3 / 100g of DBP value.

[0097] Other fillers can be used in the rubber composition, including but not limited to, particulate fillers, including ultra-high molecular weight polyethylene (∪HMWPE), cross-linked particulate polymer gels, including but not limited to those disclosed in U.S. Patent Nos. 6,242,534; 6,207,757; 6,133,364; 6,372,857; 5,395,891; or 6,127,488, and plasticized starch composite fillers, including but not limited to those disclosed in U.S. Patent No. 5,672,639. The patents mentioned in the above sentence are incorporated herein by reference in their entirety. Such other fillers can be used in an amount of 1 to 30 phr.

[0098] In some embodiments, the rubber composition may contain conventional sulfur-containing organosilicon compounds. In one embodiment, the sulfur-containing organosilicon compound is 3,3′-bis(trimethoxy or triethoxysilylpropyl)polysulfide. In one embodiment, the sulfur-containing organosilicon compound is 3,3′-bis(triethoxysilylpropyl)disulfide and / or 3,3′-bis(triethoxysilylpropyl)tetrasulfide.

[0099] In some embodiments, suitable sulfur-containing organosilicon compounds include compounds disclosed in U.S. Pat. No. 6,608,125. In one embodiment, the sulfur-containing organosilicon compound includes 3-(octanoylthio)-1-propyltriethoxysilane, CH3(CH2)6C(=O)-S-CH2CH2CH2Si(OCH2CH3)3, which can be used as NXT TM Commercially available from Momentive Performance Materials.

[0100] In another embodiment, suitable sulfur-containing organosilicon compounds include those disclosed in US Patent Publication No. 2003 / 0130535, which is incorporated herein by reference in its entirety. In one embodiment, the sulfur-containing organosilicon compound is Si-363 from Degussa.

[0101] The amount of sulfur-containing organosilicon compound in the rubber composition will vary with the amount of other additives used. Generally speaking, the amount of the compound will be from 0.5 to 20 phr. In one embodiment, the amount will be from 1 to 10 phr.

[0102] It is readily understood by those skilled in the art that the rubber composition will be compounded by methods known in the rubber compounding field, such as various sulfur-vulcanizable component rubbers and various conventional additive materials, such as sulfur donors, curing aids (such as activators and delay agents) and processing additives, such as oils, resins (including tackifying resins) and plasticizers, fillers, pigments, fatty acids, zinc oxide, waxes, antioxidants and antiozonants and peptizers. As known to those skilled in the art, according to the intended use of sulfur-vulcanizable and sulfur-vulcanized materials (rubbers), the above-mentioned additives are selected and usually used in conventional amounts. Representative examples of sulfur donors include elemental sulfur (free sulfur), disulfide amines, polymerized polysulfides and sulfur olefin adducts. In one embodiment, sulfur-vulcanizing agents are elemental sulfur. Sulfur-vulcanizing agents can be used in an amount of 0.5 to 8phr, or in an amount of 1.5 to 6phr. If a tackifying resin is used, its typical amount includes about 0.5phr to about 10phr, usually about 1phr to about 5phr. Typical amounts of processing aids include about 1 to about 50 phr. Typical amounts of antioxidants include about 1 to about 5 phr. Representative antioxidants can be, for example, diphenyl-p-phenylenediamine, such as those disclosed in The Vanderbilt Rubber Handbook (1978), pages 344 to 346. Typical amounts of antiozonants include about 1 to 5 phr. If fatty acids (which can include stearic acid) are used, their typical amounts include about 0.5 to about 3 phr. Typical amounts of zinc oxide include about 2 to about 5 phr. Typical amounts of waxes include about 1 to about 5 phr. Microcrystalline wax is generally used. Typical amounts of peptizers include about 0.1 to about 1 phr. Typical peptizers can be, for example, pentachlorothiophenol and dibenzamidodiphenyl disulfide.

[0103] Use accelerator to control the time and / or temperature required for vulcanization and improve the property of vulcanized rubber. In one embodiment, a single accelerator system, i.e., a primary accelerator, can be used. One or more primary accelerators can be used in a total amount of about 0.5 to about 4 or about 0.8 to about 1.5 phr. In another embodiment, a combination of a primary accelerator and an auxiliary accelerator can be used, wherein the auxiliary accelerator is used in a relatively small amount, such as about 0.05 to about 3 phr, to activate and improve the property of the vulcanized rubber. The combination of these accelerators can be expected to produce a synergistic effect on the final properties and to a certain extent better than those produced by using any accelerator alone. In addition, an after-effect accelerator that is not affected by normal processing temperature but produces satisfactory solidification at ordinary vulcanization temperature can be used. Vulcanization delay agents may also be used. Available accelerators of suitable types include amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates / salts and xanthates / salts. In one embodiment, the primary accelerator is a sulfenamide. If a secondary accelerator is used, it may be a guanidine, dithiocarbamate or thiuram compound.

[0104] The mixing of the rubber composition can be achieved by methods known to those skilled in the art of rubber mixing. For example, the ingredients are usually mixed in at least two stages, i.e., at least one non-productive stage and then a productive mixing stage. The final curing agent (curatives) including sulfur-vulcanizing agent is usually mixed in the last stage (which is conventionally referred to as a "productive" mixing stage, wherein the mixing is usually carried out at a temperature or final temperature lower than one or more mixing temperatures of the previous one or more non-productive mixing stages). The terms "non-productive" and "productive" mixing stages are well known to those skilled in the art of rubber mixing. The rubber composition can be subjected to a thermomechanical mixing step. The thermomechanical mixing step is usually included in a time suitable for mechanical processing in a mixer or extruder to produce a rubber temperature of 140°C to 190°C. The appropriate duration of the thermomechanical processing varies with the operating conditions and the volume and properties of the components. For example, the thermomechanical processing can be 1 to 20 minutes.

[0105] The rubber composition can be incorporated into various rubber components of a tire. For example, the rubber component can be a tread (including a tread cap and a tread base), a sidewall, an apex, a chafer, a sidewall insert, a wirecoat, or an innerliner. In one embodiment, the component is a tread.

[0106] The pneumatic tire can be a racing tire, a passenger car tire, an aircraft tire, an agricultural tire, a bulldozer tire, an off-road tire, a truck tire, etc. In one embodiment, the tire is a passenger car or truck tire. The tire can also be a radial tire or a bias tire.

[0107] The rubber composition may also be used in other products including, but not limited to, non-pneumatic tires, belts, hoses, shoes, air springs, engine mounts, and the like.

[0108] Vulcanization of the pneumatic tire may be carried out at conventional temperatures of about 100° C. to 200° C. In one embodiment, vulcanization is carried out at a temperature of about 110° C. to 180° C. Any conventional vulcanization method may be used, such as heating in a press or mold, heating with superheated steam or hot air. Such tires may be built, shaped, molded, and cured by various methods known to and as will be apparent to those skilled in the art.

[0109] Figure 3 301 according to some embodiments of the present disclosure. The tire 301 includes a tread portion 302, a bead portion 303, and a sidewall portion 304 located between the tread portion 302 and the bead portion 303. The tread portion 302, the bead portion 303, and the sidewall portion 304 of the tire according to the present disclosure are not limited to Figure 3 For example, there may be multiple sidewall sections, ribs, patterns, colors, etc. Figure 3 304. An example of a composition containing a copolymer produced according to the method disclosed herein may be used. The copolymer may be used in one or more of the tread portion 302, the bead portion 303, and the sidewall portion 304.

[0110] Figure 4 445 is a flow chart showing a non-limiting example of a method 445 of forming an article (e.g., a tire) according to some embodiments of the present disclosure. The method 445 includes providing a composition containing an ethylene-butadiene copolymer 460, non-productive mixing 470, productive mixing 480, and vulcanization 490.

[0111] The following examples are provided to illustrate the apparatus and methods of the present disclosure. The examples are merely illustrative and are not intended to limit the present disclosure to the materials, conditions, or method parameters set forth therein.

[0112] Example

[0113] A butadiene premix was prepared in toluene (15 wt%) and dried on a column of dried alumina / sieve. The premix was loaded in a 4 ounce Boston round bottle. The solution was saturated with ethylene gas by flushing with an ethylene stream for about 5 minutes. A catalyst solution in toluene was prepared under an inert atmosphere by dissolving 7.4 mg (0.0164 mmol) of tris[(trimethylsilyl)methyl]scandium (CAS 872992-17-1) in 2 mL of toluene followed by addition of MMAO-12 (100 equivalents, 1.64 mmol, 1.52 mL of a 7% solution). Another aliquot of MMAO-12 (100 equivalents, 1.64 mmol, 1.52 mL of a 7% solution) was loaded into a polymerization vessel followed by addition of all of the scandium catalyst solution. The bottle was heated to 50° C. for 3 hours, then terminated with an isopropanol / BHT solution, and evaporated to remove the solvent. The resulting polymer was analyzed by 1H NMR and 13C NMR to determine ethylene incorporation. By 13C NMR, the polymer was found to be 62% cis, 33% trans, and 5% vinyl. Ethylene incorporation by 1H NMR was found to be 7.4 mole %.

[0114] This written specification uses examples to describe the present disclosure, including the best mode, and to enable any person skilled in the art to make and use the present disclosure. Other examples that occur to those skilled in the art are intended to be within the scope of the present disclosure if they have structural elements that are not different from the same concept or if they include equivalent structural elements with insubstantial differences. It is to be recognized that variations of the above-disclosed and other features and functions, or alternatives thereto, may be combined into many other different systems or applications. Various currently unforeseen or unexpected substitutions, modifications, changes or improvements may subsequently be made by those skilled in the art, which are also intended to be covered by the following claims.

Claims

1. A method for producing an ethylene-butadiene copolymer, the method comprising: butadiene is copolymerized with ethylene in the presence of a catalyst system comprising: Tris[(trimethylsilyl)methyl]scandium; and Contains aluminum activator.

2. The method according to claim 1, wherein the catalyst system further comprises: Borate co-activator.

3. The method of claim 2, wherein the borate co-activator comprises tetrakis(3,5-bis(trifluoromethyl)phenyl)borate and / or tetrakis(pentafluorophenyl)borate.

4. The method of claim 1, wherein the aluminum-containing activator is an aluminoxane activator.

5. The method of claim 4, wherein the aluminoxane activator is a modified aluminoxane activator.

6. The method of claim 4, wherein the aluminoxane activator is a methylaluminoxane activator.

7. The method of claim 6, wherein the methylaluminoxane activator is a modified methylaluminoxane activator.

8. The method of claim 1, wherein the aluminum-containing activator comprises MMAO-12.

9. The method of claim 1, wherein the aluminum-containing activator comprises a trialkylaluminum activator; and wherein the catalyst system further comprises: Borate co-activator.

10. A method for producing an ethylene-butadiene copolymer, the method comprising: providing a first composition comprising butadiene and ethylene to a reactor; providing a second composition comprising tris[(trimethylsilyl)methyl]scandium and a first aliquot of an aluminum-containing activator to a reactor; and Copolymerize butadiene with ethylene.

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