Polybutadiene polymers for low temperature applications and rubber compositions incorporating polybutadiene polymers - Patents.com

Abstract

To provide 1,4-polybutadiene rubber compositions useful at low temperatures.MEANS FOR SOLVING THE PROBLEM: The 1,4-polybutadiene incorporated in the compositions comprises a cis content of at least 85 to about 92%, a vinyl content of about 1% to about 5%, and a trans content of about 3 to about 12%. The 1,4-polybutadiene has an enthalpy of melting ΔHm of about 5 to about 25 J / g°C as measured by differential scanning calorimetry (DSC).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 62 / 263,821, filed December 7, 2015, which is incorporated by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to 1,4-polybutadiene rubber compositions, and more particularly, to 1,4-polybutadiene rubber compositions suitable for low temperature tire applications. [Background technology]

[0003] In tire manufacturing, high cis 1,4-polybutadienes (e.g., polymers with cis-1,4 bond content of 95% or more) are commonly used due to their excellent mechanical properties. However, at low temperatures below -30°C, these compositions are prone to crystallization. At these low temperatures, tires can become stiff due to crystallization, which prevents the tire from maintaining the desired contact with the road under snow and ice conditions.

[0004] Thus, there continues to be a need for improved 1,4-polybutadiene rubber compositions that resist low temperature crystallization while maintaining suitable strength and abrasion resistance. Summary of the Invention

[0005] DETAILED DESCRIPTION OF THE DISCLOSURE Embodiments of the present disclosure are directed to 1,4-polybutadiene rubber compositions that perform well in tire and non-tire applications at low temperatures. These rubber compositions may be used, for example, in tire treads for winter tires. Furthermore, the 1,4-polybutadiene rubber compositions of the present invention are not only flexible at low temperatures, but also exhibit excellent wear resistance and excellent mechanical properties comparable to comparable or higher high cis polybutadiene rubber compositions.

[0006] According to one embodiment, there is provided a polymer comprising 1,4-polybutadiene characterized by a cis content of at least 85 to about 92%, a vinyl content of about 1 to about 5%, and a trans content of about 3 to about 12%, the polymer having an enthalpy of fusion ΔH of about 5 to about 25 J / g° C. as measured by differential scanning calorimetry (DSC). m has.

[0007] According to another embodiment, a rubber composition is provided that includes a 1,4-polybutadiene polymer, a curative, and a reinforcing filler.

[0008] In accordance with yet another embodiment of the present invention, there is provided a method for producing 1,4-polybutadiene, comprising polymerizing a solution comprising 1,3-butadiene to produce a 1,4-polybutadiene rubber having a cis content of at least 85 to about 92%, a vinyl content of about 1% to about 5%, and a trans content of about 3 to about 12%, wherein the polymerization is catalyzed by a catalyst comprising a lanthanide metal complex.

[0009] Additional features and advantages of the embodiments described herein are set forth in the Detailed Description below, and in part will be readily apparent to those skilled in the art from this description, or will become apparent from the practice of the embodiments described herein, such as in the Detailed Description, Claims, and accompanying drawings. [Brief description of the drawings]

[0010] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the drawings included herein.

[0011] [Figure 1] 1 is a graph showing the storage modulus at low temperature comparing one embodiment of an inventive 1,4-polybutadiene rubber composition to other comparative 1,4-polybutadiene rubber compositions, in accordance with one or more embodiments of the present disclosure.

[0012] [Diagram 2]1 is a graph illustrating the tensile properties at room temperature of one embodiment of an inventive 1,4-polybutadiene rubber composition in accordance with one or more embodiments of the present disclosure versus other comparative 1,4-polybutadiene rubber compositions.

[0013] The embodiments set forth in the drawings are illustrative in nature and are not intended to limit the embodiments defined by the claims. Moreover, individual features of the drawings will become more fully apparent and understood by consideration of the Detailed Description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE DISCLOSURE The present disclosure is directed to 1,4-polybutadiene rubber compositions having improved resistance to crystallization at low temperatures (e.g., below -30°C). As discussed above, crystallization at low temperatures is undesirable because it hardens the tire and prevents the tire from conforming to the road contours, especially in wet or snowy conditions. Thus, reduced crystallization at low temperatures is desirable, which is achieved by the 1,4-polybutadiene rubber compositions of the present disclosure. Specifically, the 1,4-polybutadiene rubber compositions of the present disclosure can provide improved benefits to winter tires, specifically winter tire treads. The 1,4-polybutadiene rubber compositions may include 1,4-polybutadiene polymers having a cis content of at least 85 to about 92%, a vinyl content of about 1% to about 5, and a trans content of about 3 to about 12%. As used herein, "cis content" is the ratio of cis-1,4 bonds in the 1,4-polybutadiene. Similarly, "trans content" refers to the proportion of trans-1,4 bonds in 1,4-polybutadiene. Similarly, "vinyl content" refers to the proportion of 1,2 vinyl bonds in 1,4-polybutadiene.

[0015] As used herein, "1,4-polybutadiene polymer" may refer to the polydiene before it is blended with other rubber additives to produce a rubber composition for use in tire and non-tire applications. As used herein, "1,4-polybutadiene rubber composition" or "rubber composition" refers to the polymer (e.g., 1,4-polybutadiene) and additional fillers and additives blended with the polymer for use in tire and non-tire applications.

[0016] Without being bound by theory, this vinyl content range indicates that it can inhibit and surprisingly reduce crystallization at low temperatures, such as below −30° C. As a result, the 1,4-polybutadiene rubber composition of the present invention provides improved low temperature performance, which in turn enhances performance on snow and ice when incorporated into winter tire tread compounds.

[0017] As described above, the cis content of the 1,4-polybutadiene rubber of the present invention is about 85% to about 92%. Surprisingly, the 1,4-polybutadiene rubber composition of the present disclosure does not cure at low temperatures as other 1,4-polybutadiene rubbers having similar cis contents but prepared with different polymerization catalyst systems. Thus, the composition of the present disclosure is more flexible at low temperatures (e.g., as low as -80°C) than other polybutadiene rubbers having the same or higher cis content.

[0018] In further embodiments, the 1,4-polybutadiene polymer may have a cis content of about 85% to about 90%, or about 86% to about 89%. Further, the 1,4-polybutadiene rubber may have a vinyl content of about 1% to about 3% and a trans content of about 7 to about 10%. In addition, the 1,4-polybutadiene polymer may have a narrow molecular weight distribution (MWD) of about 2.5 to about 2.5, or about 2.1 to about 2.25, where the MWD is the molecular weight distribution of about 2.5 to about 2.25. w / M n is defined as M w is the weight average molecular weight, M nis the number average molecular weight. In additional embodiments, the 1,4-polybutadiene polymer may have a weight average molecular weight of about 200,000 to about 300,000 g / mol, or about 200,000 to about 250,000 g / mol. Further, the 1,4-polybutadiene polymer may have a number average molecular weight of about 80,000 g / mol to about 150,000 g / mol, or about 100,000 g / mol to about 120,000 g / mol. Further, the 1,4-polybutadiene polymer may have a peak molecular weight (M) of about 250,000 g / mol to about 350,000 g / mol, or about 250,000 g / mol to about 300,000 g / mol. p ).

[0019] Various polymerization methods suitable for producing the 1,4-polybutadiene compositions of the present disclosure are contemplated. In one embodiment, the 1,4-polybutadiene compositions are prepared by coordination polymerization, in which a monomer (e.g., a conjugated diene monomer) is polymerized using a coordination catalyst system.

[0020] Conjugated diene monomer, as used herein, refers to a monomer composition having at least two double bonds separated by a single bond. The processes described herein may use at least one conjugated diene monomer containing less than 20 carbon atoms (i.e., 4 to 19 carbons). Examples of conjugated diene monomers include 1,3-butadiene, isoprene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, and 2,4-hexadiene. Mixtures of two or more conjugated dienes may be used in the copolymerization. While all monomers are believed to be suitable, the current discussion focuses on 1,3-butadiene monomer.

[0021] Coordination catalysts (also known as Ziegler-Natta catalysts) can include a lanthanide compound (e.g., a lanthanide metal complex), an alkylating agent (e.g., an organoaluminum compound), and a halogen compound. 1,4-polybutadiene produced by coordination polymerization is stereoselective and is particularly suitable for use in tire components such as sidewalls and treads.

[0022] A variety of procedures can be used to prepare the coordination catalyst. In one or more embodiments, the coordination catalyst can be formed in situ by separately adding the catalyst components to the monomer to be polymerized, either stepwise or simultaneously. In other embodiments, the coordination catalyst can be preformed; that is, the catalyst components are premixed outside the polymerization system in the absence of monomer or in the presence of a small amount of monomer. The resulting preformed catalyst composition can be aged, if necessary, and then added to the monomer to be polymerized.

[0023] For example, the lanthanide metal complex may include at least one atom of lanthanum, neodymium, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and didymium. In certain embodiments, the lanthanide compound includes gadolinium.

[0024] The lanthanide atom in the lanthanide metal complex may be in various oxidation states, including, but not limited to, 0, +2, +3, and +4. Suitable lanthanide compounds include, but are not limited to, lanthanide carboxylates, lanthanide organophosphates, lanthanide organophosphonates, lanthanide organophosphinates, lanthanide carbamates, lanthanide dithiocarbamates, lanthanide xanthates, lanthanide β-diketonates, lanthanide alkoxides or aryloxides, lanthanide halides, lanthanide pseudohalides, lanthanide oxyhalides, and organolanthanide compounds. The lanthanides may also include lanthanide metallocene compounds. In one embodiment, the lanthanide metallocene compound may be bis(2-phenylindanyl)gadolinium bis(dimethylsilyl)amide. Further details regarding lanthanide metallocene compounds are described in U.S. Patent Application Publication No. 20140005296, which is incorporated herein by reference in its entirety.

[0025] As further described above, the catalyst system can include an alkylating agent. The alkylating agent can include at least one organoaluminum compound. As used herein, the term organoaluminum compound refers to any aluminum compound that contains at least one aluminum-carbon bond. In one or more embodiments, an organoaluminum compound that is soluble in a hydrocarbon solvent can be used.

[0026] For example, organoaluminum compounds that can be used include those of the general formula AlR n X 3-nwherein each R may independently be a monovalent organic group bonded to the aluminum atom through a carbon atom, each X may independently be a hydrogen atom, a halogen atom (e.g., fluorine, chlorine, bromine, or iodine), a carboxylate group, an alkoxide group, or an aryloxide group, and n may be an integer ranging from 1 to 3. When the organoaluminum compound contains a fluorine atom, the organoaluminum compound can function as both an alkylating agent and at least a portion of the fluorine source in the catalyst system. In one or more embodiments, each R may independently be a hydrocarbyl group, such as an alkyl group, a cycloalkyl group, a substituted cycloalkyl group, an alkenyl group, a cycloalkenyl group, a substituted cycloalkenyl group, an aryl group, a substituted aryl group, an aralkyl group, an alkaryl group, an aryl group, and an alkynyl group, each group containing from 1 carbon atom (or the minimum number of carbon atoms suitable to form the group) up to about 20 carbon atoms. These hydrocarbyl groups may contain heteroatoms such as, but not limited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms.

[0027] General formula AlR n X 3-n Classes of organoaluminum compounds represented by include, but are not limited to, trihydrocarbylaluminum, dihydrocarbylaluminum hydrides, hydrocarbylaluminum dihydrides, dihydrocarbylaluminum carboxylates, hydrocarbylaluminum bis(carboxylates), dihydrocarbylaluminum alkoxides, hydrocarbylaluminum dialkoxides, dihydrocarbylaluminum halides, hydrocarbylaluminum dihalides, dihydrocarbylaluminum aryloxides, and hydrocarbylaluminum diaryloxide compounds. In one embodiment, the alkylating agent can include trihydrocarbylaluminum, dihydrocarbylaluminum hydride, and / or hydrocarbylaluminum dihydride compounds.

[0028] Suitable trihydrocarbylaluminum compounds include, but are not limited to, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, tri-t-butylaluminum, tri-n-pentylaluminum, trineopentylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tris(2-ethylhexyl)aluminum, tricyclohexylaluminum, tris(1-methylcyclopentyl)aluminum, triphenylaluminum, tri-p-tolylaluminum, tris(2,6-dimethylphenyl)aluminum, tribenzylaluminum, diethylphenylaluminum, diethyl-p-tolylaluminum, diethylbenzylaluminum, ethyldiphenylaluminum, ethyldi-p-tolylaluminum, and ethyldibenzylaluminum.

[0029] Suitable dihydrocarbylaluminum hydride compounds include diethylaluminum hydride, di-n-propylaluminum hydride, diisopropylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, di-n-octylaluminum hydride, diphenylaluminum hydride, di-p-tolylaluminum hydride, dibenzylaluminum hydride, phenylethylaluminum hydride, phenyl-n-propylaluminum hydride, phenylisopropylaluminum hydride, phenyl-n-butylaluminum hydride, phenylisobutylaluminum hydride, phenyl- Examples of aluminum hydride include, but are not limited to, n-octylaluminum hydride, p-tolylethylaluminum hydride, p-tolyl-n-propylaluminum hydride, p-tolylisopropylaluminum hydride, p-tolyl-n-butylaluminum hydride, p-tolylisobutylaluminum hydride, p-tolyl-n-octylaluminum hydride, benzylethylaluminum hydride, benzyl-n-propylaluminum hydride, benzylisopropylaluminum hydride, benzyl-n-butylaluminum hydride, benzylisobutylaluminum hydride, and benzyl-n-octylaluminum hydride.

[0030] Suitable hydrocarbylaluminum dihydrides include, but are not limited to, ethylaluminum dihydride, n-propylaluminum dihydride, isopropylaluminum dihydride, n-butylaluminum dihydride, isobutylaluminum dihydride, and n-octylaluminum dihydride.

[0031] Suitable dihydrocarbylamine aluminum halogen compounds include diethylaluminum chloride, di-n-propylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, diphenylaluminum chloride, di-p-tolylaluminum chloride, dibenzylaluminum chloride, phenylethylaluminum chloride, phenyl-n-propylaluminum chloride, phenylisopropylaluminum chloride, phenyl-n-butylaluminum chloride, phenylisobutylaluminum chloride. , phenyl-n-octyl aluminum chloride, p-tolyl ethyl aluminum chloride, p-tolyl-n-propyl aluminum chloride, p-tolyl isopropyl aluminum chloride, p-tolyl-n-butyl aluminum chloride, p-tolyl isobutyl aluminum chloride, p-tolyl-n-octyl aluminum chloride, benzyl ethyl aluminum chloride, benzyl-n-propyl aluminum chloride, benzyl isopropyl aluminum chloride, benzyl-n-butyl aluminum chloride, benzyl isobutyl aluminum Chloride, benzyl-n-octyl aluminum chloride, diethyl aluminum fluoride, di-n-propyl aluminum fluoride, diisopropyl aluminum fluoride, di-n-butyl aluminum fluoride, diisobutyl aluminum fluoride, di-n-octyl aluminum fluoride, diphenyl aluminum fluoride, di-p-tolyl aluminum fluoride, dibenzyl aluminum fluoride, phenylethyl aluminum fluoride, phenyl-n-propyl aluminum fluoride, phenylisopropyl aluminum Fluoride, phenyl-n-butylaluminum fluoride, phenyl isobutylaluminum fluoride, phenyl-n-octylaluminum fluoride, p-tolylethylaluminum fluoride, p-tolyl-n-propylaluminum fluoride, p-tolylisopropylaluminum fluoride, p-tolyl-n-butylaluminum fluoride, p-tolylisobutylaluminum fluoride, p-tolyl-n-octylaluminum fluoride, benzyl ethylaluminum fluoride, benzyl-n-propylaluminum fluoride,Examples of suitable aluminum fluorides include, but are not limited to, benzyl isopropyl aluminum fluoride, benzyl-n-butyl aluminum fluoride, benzyl isobutyl aluminum fluoride, and benzyl-n-octyl aluminum fluoride.

[0032] Suitable hydrocarbylaluminum dihalide compounds include, but are not limited to, ethylaluminum dichloride, n-propylaluminum dichloride, isopropylaluminum dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride, n-octylaluminum dichloride, ethylaluminum difluoride, n-propylaluminum difluoride, isopropylaluminum difluoride, n-butylaluminum difluoride, isobutylaluminum difluoride, and n-octylaluminum difluoride.

[0033] General formula AlR n X 3-nOther organoaluminum compounds useful as alkylating agents that may be represented by the formula (I) include dimethylaluminum hexanoate, diethylaluminum octoate, diisobutylaluminum 2-ethylhexanoate, dimethylaluminum neodecanoate, diethylaluminum stearate, diisobutylaluminum oleate, methylaluminum bis(hexanoate), ethylaluminum bis(octoate), isobutylaluminum bis(2-ethylhexanoate), methylaluminum bis(neodecanoate), ethylaluminum bis(stearate), isobutylaluminum bis(oleate), dimethylaluminum methoxide, diethylaluminum bis(hexanoate), di ...hexanoate), diethylaluminum bis(octoate), isobutylaluminum bis(2-ethylhexanoate), Examples of suitable aluminum methoxides include, but are not limited to, aluminum methoxide, diisobutylaluminum methoxide, dimethylaluminum ethoxide, diethylaluminum ethoxide, diisobutylaluminum ethoxide, dimethylaluminum phenoxide, diethylaluminum phenoxide, diisobutylaluminum phenoxide, methylaluminum dimethoxide, ethylaluminum dimethoxide, isobutylaluminum dimethoxide, methylaluminum diethoxide, ethylaluminum diethoxide, isobutylaluminum diethoxide, methylaluminum diphenoxide, ethylaluminum diphenoxide, and isobutylaluminum diphenoxide.

[0034] Another class of organoaluminum compounds suitable for use as alkylating agents in the present disclosure are aluminoxanes, such as oligomeric linear aluminoxanes. U.S. Patent Application Publication No. 2008 / 0182954 and U.S. Patent No. 8,987,395, which are incorporated herein by reference in their entirety, provide other examples of aluminoxanes and organoaluminum compounds. In an exemplary embodiment, the alkylating agent is diisobutylaluminum hydride.

[0035] Organomagnesium and organozinc compounds are also contemplated as alternatives or complements to organoaluminum. These organomagnesium and organozinc compounds are described in U.S. Patent Application Publication No. 20140073751, which is incorporated herein by reference in its entirety.

[0036] A variety of compounds (or mixtures thereof) containing one or more types of halogen atoms can be used. These are often referred to as non-coordinating compounds. Examples of halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine. Combinations of two or more types of halogen atoms with different types of halogen atoms can also be used. In one or more embodiments, the halogen compounds may be soluble in hydrocarbon solvents. In other embodiments, hydrocarbon-insoluble halogen compounds that can be suspended in the polymerization medium to form catalytically active species may be useful. Suitable types of halogen compounds include elemental halogens, mixed halogens, hydrogen halides, organic halides, inorganic halides, metal halides, and organometallic halides.

[0037] Elemental halogens include fluorine, chlorine, bromine and iodine. Mixed halogens include iodine monochloride, iodine monobromide, iodine trichloride and iodine pentafluoride. Hydrogen halides include hydrogen fluoride, hydrogen chloride, hydrogen bromide and hydrogen iodide. Organic halides include t-butyl chloride, t-butyl bromide, allyl chloride, allyl bromide, benzyl chloride, benzyl bromide, chloro-di-phenylmethane, bromo-di-phenylmethane, triphenylmethyl chloride, triphenylmethyl bromide, benzylidene chloride, benzylidene bromide, methyltrichlorosilane, phenyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, trimethylchlorosilane, benzoyl chloride, benzoyl bromide, propionyl chloride, propionyl bromide, methylchloroformate and methylbromoformate.

[0038] Inorganic halides include phosphorus trichloride, phosphorus tribromide, phosphorus pentachloride, phosphorus oxychloride, phosphorus oxybromide, boron trifluoride, boron trichloride, boron tribromide, silicon tetrafluoride, silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, arsenic trichloride, arsenic tribromide, arsenic triiodide, selenium tetrachloride, selenium tetrabromide, tellurium tetrachloride, tellurium tetrabromide, and tellurium tetraiodide. Metal halides include tin tetrachloride, tin tetrabromide, aluminum trichloride, aluminum tribromide, antimony trichloride, antimony pentachloride, antimony tribromide, aluminum triiodide, aluminum trifluoride, gallium trichloride, gallium tribromide, gallium triiodide, gallium trifluoride, indium trichloride, indium tribromide, indium triiodide, indium trifluoride, titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, zinc dichloride, zinc dibromide, zinc diiodide, and zinc difluoride.

[0039] Organometallic halides include dimethylaluminum chloride, diethylaluminum chloride, dimethylaluminum bromide, diethylaluminum bromide, dimethylaluminum fluoride, diethylaluminum fluoride, methylaluminum dichloride, ethylaluminum dichloride, methylaluminum dibromide, ethylaluminum dibromide, methylaluminum difluoride, ethylaluminum difluoride, methylaluminum sesquichloride, ethylaluminum sesquichloride, isobutylaluminum sesquichloride, methylmagnesium chloride, Examples of magnesium ions include methyl magnesium bromide, methyl magnesium iodide, ethyl magnesium chloride, ethyl magnesium bromide, butyl magnesium chloride, butyl magnesium bromide, phenyl magnesium chloride, phenyl magnesium bromide, benzyl magnesium chloride, trimethyl tin chloride, trimethyl tin bromide, triethyl tin chloride, triethyl tin bromide, di-t-butyl tin dichloride, di-t-butyl tin dibromide, dibutyl tin dichloride, dibutyl tin dibromide, tributyl tin chloride, and tributyl tin bromide.

[0040] Compounds containing non-coordinating anions are well known in the art. In general, non-coordinating anions are sterically bulky anions that do not form coordinate bonds with, for example, the active center of a catalyst system due to steric hindrance. Exemplary non-coordinating anions include tetraarylborate anions and fluorinated tetraarylborate anions. Compounds containing non-coordinating anions also contain counter cations, such as carbonium, ammonium, or phosphonium cations. Exemplary counter cations include triarylcarbonium cations and N ,Examples of compounds containing non-coordinating anions and counter cations include triphenylcarbonium tetra(pentafluorophenyl)borate, N,N-dimethylanilinium tetra(pentafluorophenyl)borate, triphenylcarbonium tetra[3,5-bis(trifluoromethyl)phenyl]borate, and N,N-dimethylanilinium tetra[3,5-bis(trifluoromethyl)phenyl]borate. In an exemplary embodiment, the halogen compound is N,N-dimethylanilinium tetra(pentafluorophenyl)borate.

[0041] As noted above, the inclusion of these 1,4-polybutadienes in 1,4-polybutadiene rubber compositions provides improved resistance to crystallization at low temperatures. Without being bound by theory, the melt enthalpy of 1,4-polybutadiene polymers is one characteristic that correlates with reduced crystallization in low temperature tire applications. For example, 1,4-polybutadiene has a melt enthalpy ΔH of about 5 to about 25 J / g° C. as measured by differential scanning calorimetry (DSC). m In further embodiments, the 1,4-polybutenes may have an enthalpy of fusion ΔH of from about 10 to about 20, or from about 10 to about 15 J / g° C., as measured by DSC. m Additionally, the 1,4-polybutadiene polymer may have a low melting temperature (T m ), which further exhibits resistance to cold crystallization. For example, T m may be less than −20° C. or less than −25° C. In other words, T m The temperature may be from about -20°C to about -40°C, or from about -20°C to about -30°C.

[0042] As mentioned above, these rubber compositions may include 1,4-polybutadiene polymers and various other ingredients and fillers as described herein, such as reinforcing fillers and curatives. Fillers that can be used include those fillers conventionally used in tire manufacturing. Useful fillers include inorganic and organic fillers. Organic fillers include carbon black and starch. Inorganic fillers can include silica, aluminum hydroxide, magnesium hydroxide, clay (hydrated aluminum silicate), and mixtures thereof. In one embodiment, the reinforcing filler may include carbon black, silica, or a combination thereof. In one or more embodiments, the curative may include sulfur or a sulfur donor.

[0043] In addition to the 1,4-polybutadiene polymers mentioned above, natural rubber or other elastomeric materials may be included, such as polybutadiene, polyisoprene, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), and synthetic rubbers such as poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubbers, acrylic rubbers, urethane rubbers, silicone rubbers, epichlorohydrin rubbers, and mixtures thereof.

[0044] Also, useful processing or extending oils may be included. Preferred oils include those commercially available as paraffinic, aromatic, or naphthenic oils. In one or more embodiments, the oil is primarily paraffinic. In one embodiment, the extending oil may be sulfur-extended. The tire components may also include other additives such as antiozonants, waxes, scorch inhibitors, processing aids, zinc oxide, tackifiers, reinforcing resins, fatty acids such as stearic acid, peptizing agents, and one or more accelerators.

[0045] Antiozonants may include N,N'-disubstituted-p-phenylenediamines such as N-1,3-dimethylbutyl-N'phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N-phenyl-N-isopropyl-p-phenylenediamine (IPPD), and N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (HPPD). Other examples of antiozonants include acetone diphenylamine condensation products (Alchem ​​BL), 2,4-trimethyl-1,2-dihydroquinoline (TMQ), octylated diphenylamine (ODPA), and 2,6-di-t-butyl-4-methylphenol (BHT).

[0046] The curing accelerator may include, but is not limited to, dithiocarbamate accelerators, including metal dialkyl dithiocarbamates, such as zinc dibutyl dithiocarbamate (ZDBDC), zinc diethyl dithiocarbamate, zinc dimethyl dithiocarbamate, and iron dimethyl dithiocarbamate; thiazole accelerators, including benzothiazole disulfides, such as 2-mercaptobenzothiazole, such as mercaptobenzothiazole disulfide (MBTS); benzothiazole sulfenamides, such as n-cyclohexyl-2-benzothiazole sulfenamide, and sulfenamide accelerators, such as t-butyl-2-benzothiadiyl sulfenamide (TBBS). In addition, the curing accelerator may also include diphenyl guanidine (DPG).

[0047] Various amounts of 1,4-polybutadiene polymer are contemplated within the tire components. In one or more embodiments, out of 100 parts total rubber, the 1,4-polybutadiene polymer may comprise from about 20 to about 100 parts of the 100 total, or from about 25 to about 75 parts of the 100 total, particularly in embodiments where the 1,4-polybutadiene polymer is blended with the natural or synthetic rubbers described above.

[0048] In terms of tensile properties, the 1,4-polybutadiene rubber composition also has a complex modulus G of about 10,000,000 to about 20,000,000 Pa, or about 10,000,000 to about 15,000,000 Pa at -20°C. * At a low temperature of −30° C., the 1,4-polybutadiene rubber composition may have a complex modulus G of about 10,000,000 to about 20,000,000 Pa or about 15,000,000 to about 20,000,000 Pa. * Without being bound by theory, this complex modulus G * indicates the suitability of 1,4-polybutadiene rubber compositions at lower temperatures.

[0049] As further described in the Examples below, the 1,4-polybutadiene rubber composition has an abrasion index of at least 90%, or at least 95%, or at least 100%, as measured by the Lambourn abrasion index at 25% slip (see comparison with Nd high cis BR composition (Comparative Example 1) in Table 3 below). EXAMPLES

[0050] Example 1 and Comparative Examples 2 to 4: Synthesis of 1,4-polybutadiene

[0051] To a 2 gallon nitrogen purged reactor equipped with a turbine agitator blade, 1600 g of hexane and 1959 g of a 21.3 wt% 1,3-butadiene solution in hexane were added. The reactor jacket was then set to 50°C. A preformed catalyst was prepared by mixing 50 mL of toluene, 5.10 mL of 1.08 M diisobutylaluminum hydride in toluene, 168 mg (0.250 mmol) of bis(2-phenylindenyl)gadolinium bis(dimethylsilyl imide), and 211 mg (0.263 mmol) of N,N-dimethylanilinium tetra(pentafluorophenyl)borate, in that order, and aging at room temperature for 20 minutes. The catalyst was then charged to the reactor and the reactor jacket temperature was set to 80°C. ° Ninety minutes after catalyst addition, the resulting polymer cement was added dropwise to 12 liters of isopropanol containing 5 g of 2,6-di-tert-butyl-4-methylphenol. The coagulated polymer was drum dried to give 360 ​​g of polymer (86% yield). Properties of the resulting 1,4-polybutadiene are summarized and compared to three comparative examples in Table 1 below.

[0052] [Table 1]

[0053] An exemplary embodiment (Example 1), a gadolinium catalyzed polybutadiene polymer, was evaluated in carbon black filled compounds and compared to a commercial grade high cis (96%) polybutadiene rubber polymerized with a Nd catalyst (Comparative Example 1), a commercial grade low cis (33%) polybutadiene rubber polymerized with a BuLi catalyst (Comparative Example 2), and an 89% cis polybutadiene rubber polymerized with a Nd catalyst (Comparative Example 3). These compositions are shown in Table 2 below.

[0054] [Table 2]

[0055] Referring to the graph in Figure 1, the composition of Example 1 surprisingly exhibits excellent performance at low temperatures as shown by the storage modulus measured from the temperature sweep. The rubber composition of Example 1 was soft as the 33% cis polybutadiene rubber composition (Comparative Example 2) at temperatures as low as about -30°C and remained softer as the temperature decreased further. This result was unexpected since the cis content of this rubber is relatively high. In fact, a Nd-catalyzed polybutadiene rubber composition with a similar cis content (89%) (Comparative Example 3) stiffened at temperatures as low as -60°C to -20°C.

[0056] As shown in Table 3, Example 1 remained softer as indicated by a lower complex modulus at -30°C than either the higher cis (96%) polybutadiene rubber composition (Comparative Example 1) or the nearly identical cis (89%) polybutadiene rubber composition (Comparative Example 3). Table 3 - Dynamic Mechanical Properties of Compositions Containing 1,4-Polybutadiene Rubber from Table 1

[0057] [Table 3]

[0058] Referring to Figure 2, the low cis (33%) composition (Comparative Example 2) exhibited lower tensile strength and elongation at break than the 96% cis polybutadiene rubber composition (Comparative Example 1). The 89% cis Nd polybutadiene rubber composition (Comparative Example 3) achieved a lower modulus than Comparative Example 1 throughout the elongation range. However, Example 1 exhibited tensile properties comparable to Comparative Example 1. Thus, in addition to superior performance at low temperatures, Example 1 also exhibits, for example, superior tensile properties.

[0059] With respect to the abrasion loss measured by the Lambourn abrasion tester, the example of low cis polybutadiene (Comparative Example 2) was G in Table 3. *As shown by the values, the abrasion resistance was significantly lower than that of the 96% cis polybutadiene (Comparative Example 1) even though it maintained its performance at low temperatures. However, the abrasion resistance of Example 1 was equivalent to that of Comparative Example 1 at 25% slip while maintaining the low temperature performance described above. These are shown in Table 4 below.

[0060] [Table 4]

[0061] Test Method

[0062] Mooney Viscosity: The Mooney viscosity of the polymers disclosed herein was measured at 100°C using an Alpha Technologies Mooney Viscometer with a large rotor, a 1 minute preheat time, and a 4 minute run time. More specifically, the Mooney viscosity was measured by preheating each polymer to 100°C for 1 minute before the rotor was started. The Mooney viscosity was recorded for each sample as the torque 4 minutes after the rotor was started. The torque relaxation was recorded after the 4 minute measurement was completed. This t 80 The values ​​represent the time required for each polymer to decay to 80% of its torque.

[0063] Gel Permeation Chromatography (GPC) and Fourier Transform Infrared Spectroscopy (FTIR)

[0064] The molecular weight of the polymer (M n , M w , and M p (Peak M of GPC curve n )) and molecular weight distribution (M W / M n ) were measured. The GPC measurements disclosed herein are calibrated with polybutadiene standards and the Mark-Houwink constants of the polydiene produced.

[0065] Differential Scanning Calorimetry (DSC): DSC measurements are performed on a TA Instruments Q2000 using helium purge gas and the LNCS accessory for cooling. Samples were prepared in TZero aluminum pans and scanned at 10° C. / min across the temperature range of interest.

[0066] The polymer microstructure (cis, trans, and vinyl content) was measured by FTIR, specifically, samples were dissolved in CS2 and FTIR was run on a Perkin Elmer Spectrum GX instrument.

[0067] Viscoelastic Properties: The viscoelastic properties of the cured rubber compounds were measured by temperature sweep tests performed on an Advanced Rheometric Expansion System (ARES) manufactured by TA Instruments. The test specimens were rectangular in shape with a length of 47 mm, a thickness of 2 mm, and a width of 12.7 mm. The length of the sample, i.e. the gap, between the grips of the testing machine was approximately 27 mm. The tests were performed using a frequency of 62.8 rad / sec. The temperature was started at -100°C and increased to 100°C. The strains were 0.1% to 0.25% for the temperature range of -100°C to -10°C and 2% for the temperature range above -10°C.

[0068] Tensile Properties: Mechanical tensile properties were measured using micro dumbbell specimens with dimensions of 4 mm width and 1.91 mm thickness following guidelines including but not limited to the standard procedures described in ASTM D412. A specific gauge length of 44 mm was used for tensile testing. The specimens were strained at a constant rate and the resulting force was recorded as a function of elongation (strain). The force readouts were expressed as engineering stress with reference to the original cross-sectional area of ​​the specimen. The specimens were tested at 23°C. The same mechanical tensile properties were also tested at 100°C. The maximum stress and maximum strain rate were also measured at both temperatures.

[0069] Abrasion resistance: The abrasion resistance of the rubber composition was measured (as a tire abrasion performance index) using a Lambourn abrasion tester. A circular test piece was placed on a shaft and brought into contact with the abrasion surface at a slip ratio of 25% caused by the difference in linear speed between the abrasion surface and the sample surface. Talc powder was used as a lubricant. The test piece was weighed before and after the test, the amount of material loss was measured, and the average rate of material loss was used to calculate the abrasion index (typically using 3 to 5 data points).

[0070] A first aspect of the present disclosure may be directed to a polymer comprising 1,4-polybutadiene having a cis content of at least 85 to about 92%, a vinyl content of about 1% to about 5, and a trans content of about 3 to about 12%, the polymer having an enthalpy of fusion ΔH of about 5 to about 25 J / g° C. as measured by differential scanning calorimetry (DSC). m has.

[0071] A second embodiment of the present disclosure may include the first embodiment, wherein the cis content is from about 85% to about 90%, the vinyl content is from about 1 to about 3%, and the trans content is from about 5% to about 10%.

[0072] A third aspect of the present disclosure may include the first and second aspects, wherein the 1,4-polybutadiene has a melting temperature (T m ).

[0073] A fourth aspect of the present disclosure may include any of the first to third aspects, wherein the 1,4-polybutadiene has a peak molecular weight of about 250,000 g / mol to about 350,000 g / mol.

[0074] A fifth aspect of the present disclosure may include any of the first to fourth aspects, and further comprises a melting enthalpy ΔH m is about 10 to about 20 J / g°C.

[0075] A sixth aspect of the present disclosure may be directed to a rubber composition, which may include the polymer of any of the first to fifth aspects, a reinforcing filler, and a curing agent.

[0076] An eighth aspect of the present disclosure may include the sixth or seventh aspect, wherein the reinforcing filler includes sulfur and the curative includes carbon black.

[0077] A ninth aspect of the present disclosure may include any of the sixth to eighth aspects, wherein the rubber composition further includes a natural rubber, an additional synthetic rubber, or a combination thereof.

[0078] A tenth aspect of the present disclosure may include the ninth aspect, wherein the additional synthetic rubber comprises polybutadiene, polyisoprene, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), and poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, or mixtures thereof.

[0079] An eleventh aspect of the present disclosure may be directed to a method, the method including polymerizing a solution comprising 1,3-butadiene to produce 1,4-polybutadiene having a cis content of at least 85 to about 92%, a vinyl content of about 1% to about 5, and a trans content of about 3 to about 12%, the polymerization being catalyzed by a catalyst comprising a lanthanide metal complex, the 1,4-polybutadiene having an enthalpy of fusion ΔH of about 5 to about 25 J / g° C. as measured by differential scanning calorimetry (DSC). m has.

[0080] A twelfth aspect of the present disclosure may include the eleventh aspect, wherein the lanthanide metal complex includes one or more of lanthanum, neodymium, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and didymium.

[0081] A thirteenth aspect of the present disclosure may include either the eleventh or twelfth aspects, wherein the lanthanide metal complex includes gadolinium.

[0082] A fourteenth aspect of the present disclosure may include any of the eleventh to thirteenth aspects, wherein the catalyst further includes a non-coordinating compound and an alkylating agent.

[0083] A fifteenth aspect of the present disclosure may include any of the eleventh to fourteenth aspects, wherein the cis content is from about 85% to about 90%, the vinyl content is from about 1% to about 3%, and the trans content is from about 5% to about 10%.

[0084] It will be apparent that modifications and variations are possible without departing from the scope of the present disclosure, as defined in the appended claims. More specifically, although certain aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to those aspects.

Claims

1. A polymer comprising: 1,4-polybutadiene having a cis content of 85 to 90%, the polymer has a melting enthalpy ΔHm of 10 to 20 J / g° C. as measured by differential scanning calorimetry (DSC); the 1,4-polybutadiene having a peak molecular weight of 250,000 g / mol to 350,000 g / mol; the 1,4-polybutadiene has a melting temperature (Tm) of −20° C. to −40° C.; the 1,4-polybutadiene having a vinyl content of 1 to 5% and a trans content of 3 to 12%, A polymer having a number average molecular weight of 80,000 g / mol to 120,000 g / mol.

2. 2. The polymer of claim 1, wherein the peak molecular weight is from 250,000 g / mol to 300,000 g / mol.

3. 2. The polymer of claim 1, wherein said vinyl content is from 1 to 3% and said trans content is from 5 to 10%.

4. A rubber composition comprising: The polymer according to claim 1 ; A reinforcing filler; and a curing agent.

5. The rubber composition has a complex modulus G of 10,000,000 to 20,000,000 Pa at −30° C. ＊ The rubber composition according to claim 4, having

6. The rubber composition of claim 4, wherein said reinforcing filler comprises carbon black and said curative comprises sulfur.

7. The rubber composition of claim 4 further comprising natural rubber, additional synthetic rubber, or a combination thereof.

8. 8. The rubber composition of claim 7, wherein the additional synthetic rubber comprises polybutadiene, polyisoprene, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), and poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, or mixtures thereof.

9. A method for producing the polymer of claim 1, comprising the steps of: polymerizing a solution comprising 1,3-butadiene to produce 1,4-polybutadiene having a cis content of at least 85-90%, said polymerization being catalyzed by a catalyst comprising a lanthanide metal complex; The polymer comprising 1,4-polybutadiene has a melting enthalpy ΔHm of 10 to 20 J / g° C. as measured by differential scanning calorimetry (DSC); the 1,4-polybutadiene has a peak molecular weight of 250,000 g / mol to 350,000 g / mol; the 1,4-polybutadiene has a melting temperature (Tm) of −20° C. to −40° C.; The 1,4-polybutadiene has a vinyl content of 1 to 5% and a trans content of 3 to 12%.

10. 10. The method of claim 9, wherein the lanthanide metal complex comprises one or more of lanthanum, neodymium, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and didymium.

11. The method of claim 9 , wherein the lanthanide metal complex comprises gadolinium.

12. 10. The method of claim 9, wherein the catalyst further comprises a non-coordinating compound and an alkylating agent.

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