Grafted EPDM polymer and rubber composition using the same polymer

Abstract

To provide macromolecules with a tendency to exhibit smaller EPDM domains, i.e., better dispersion.SOLUTION: A macromolecule comprises EPDM and a grafted chain comprising polyene mer, wherein the grafted chain has an Mn of from 50 to 250 kg / mol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to grafted EPDM polymers and rubber compositions using the same. This international application claims the benefits of U.S. Patent Application No. 63 / 132,537, filed on 31 December 2020, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Rubber products such as tire components (e.g., treads, sidewalls, etc.) are often made from elastomer compositions containing one or more reinforcing materials, such as granular carbon black and silica.

[0003] While good traction and wear resistance are primary considerations for tire treads, minimizing rolling resistance, which correlates with reduced hysteresis and heat generation during tire operation, is also discussed due to concerns about vehicle fuel efficiency. These considerations are highly competitive and somewhat contradictory, as treads made from compositions designed to provide good road traction typically exhibit high rolling resistance, and vice versa.

[0004] With regard to tire sidewalls, ozone resistance is a primary consideration, but a competing consideration is the tendency to desire a reduction in the overall weight of the tire (to improve the fuel efficiency of the vehicle). However, when the amount of rubber composition used to provide the sidewall components is reduced, ozone resistance tends to decrease due to the resulting decrease in the amount of antioxidants present.

[0005] Ozone resistance is crucial in tire sidewalls, and therefore interest in incorporating ethylene / propylene / diene monomer (EPDM) polymers internally remains. EPDM is known to have high resistance to ozone (and thus to ozonolysis), although its resistance to crack growth is not particularly good. The latter can be addressed by using blends containing EPDM. Nevertheless, incorporating EPDM in place of another polymer in such rubber compositions tends to allow for a reduction in the amount of antioxidants included in the composition, which is desirable for the aforementioned weight reduction reasons.

[0006] Vulcanized products prepared from the types of blends described above may suffer from ozone-induced cracking unless the amount of EPDM reaches a critical minimum, often around 25 phr of EPDM. This is theorized to be due to the tendency of EPDM to disperse improperly in polymers containing conjugated diemers, such as polybutadiene (BR) and natural rubber (NR).

[0007] What remains desirable is a cost-effective method for improving the dispersion of EPDM in such polymers. Also desirable are rubber compositions that can withstand ozone-induced cracking even when the amount of EPDM used is below the aforementioned critical minimum, as well as vulcanized products prepared therefrom. [Overview of the Initiative]

[0008] Disclosure of the invention Provided herein are polymers in which a polymer containing or consisting of a polyemer (e.g., polydiene) is grafted onto EPDM, with the bonding sites being the positions previously occupied by residual unsaturation of the latter diene monomer moiety. The resulting polymers tend to exhibit smaller EPDM domains, i.e., better dispersion, than simple blends.

[0009] In another embodiment, a method is provided for providing a polymer in which a functionalized EPDM reacts with a carbanion polymer, for example, a polyemer such as a polydiene. The functional group of the functionalized EPDM is reactive with carbanions, and epoxy groups are a non-limiting example.

[0010] The inclusion of polymers in a rubber composition can allow for a reduction in the total amount of EPDM contained without reducing the resistance to ozone-induced cracking in the resulting vulcanized product.

[0011] Other aspects of the present invention will be obvious to those skilled in the art from the following detailed description. Certain definitions are given below to aid in understanding that description, and these will apply throughout unless the surrounding text explicitly indicates otherwise. The term "polymer" refers to the polymerization product of one or more monomers, and includes homopolymers, copolymers, terpolymers, tetrapolymers, and so on. A "mer" or "mer unit" refers to a polymer portion derived from a single reacting molecule (for example, an ethylene mer has the general formula -CH2CH2-). A "copolymer" refers to a polymer containing mer units derived from two reactants, usually monomers, and includes random copolymers, block copolymers, segmented copolymers, graft copolymers, and others. An "interpolymer" refers to a polymer containing at least two reactants, usually mer units derived from monomers, and includes copolymers, terpolymers, tetrapolymers, and so on. "Rubber Mooney viscosity" is the Mooney viscosity of the uncured polymer before the addition of any filler. "Substitution" means the inclusion of a heteroatom or functional group (e.g., a hydrocarbyl group) that does not hinder the intended purpose of the group in question. "Direct bonding" refers to covalent bonding without any intervening atoms or groups. "Polyene" means a molecule having at least two double bonds in the longest part or molecular chain, and specifically includes diene, triene, etc. "Polydiene" means a polymer containing one or more diene mer units. "Rubber" means a natural and / or synthetic polymer containing at least 50% (w / w) polyene polymer. "phr" means parts by weight (pbw) per 100 parts by weight (pbw) of rubber.

[0012] Throughout this specification, all values given in percentage form are weight percentages (w / w) unless the surrounding context clearly indicates the contrary intention.

[0013] Unless otherwise stated, all numbers representing amounts of components, process conditions (e.g., time and temperature), etc. should be understood as essentially including the term "about". The recited numerical limitations include appropriate precision based on the number of significant digits used, e.g., "up to 5.0" can be read as setting an absolute upper limit lower than "up to 5".

[0014] The relevant teachings of all patent documents referred to throughout are incorporated herein by reference.

Mode for Carrying Out the Invention

[0015] The polymers outlined in the previous section have parts resulting from polymers including EPDM and polyene polymers such as, for example, polydiene.

[0016] Regarding the method for producing the polymer, any EPDM can be used. All EPDM polymers have residual unsaturation points, i.e., double bonds that are not part of the cyclic portion of the diene monomer. This residual unsaturation can be substituted with functional groups more susceptible to reaction with carbanions, as will be described in detail below.

[0017] An example of such a functional group is the epoxy group. The residual unsaturation of EPDM can be replaced by an epoxy group via the reaction of EPDM with an epoxidizing agent, such as m-chloroperoxybenzoic acid. This type of reaction typically does not require high temperatures and can be carried out in any solvent in which the two reactants are at least somewhat soluble. An exemplary set of conditions is provided in the Examples section below.

[0018] Grafted segments of polymers arise from carbanion polymers, specifically from terminally active polymers including polyemmers, particularly diemers, and even conjugated diemers.

[0019] Polyemers provide ethylenically unsaturated polymer chains. Unsaturated mers can arise from the incorporation of polyenes, particularly dienes and trienes (e.g., myrcenes). Exemplary polyenes include C4-C 12 Examples of dienes include, but are not limited to, conjugated dienes such as 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and 1,3-hexadiene.

[0020] Polyenes can be incorporated into polymer chains using two or more methods. Controlling this incorporation method is sometimes desirable, and techniques for achieving this control are discussed below.

[0021] Polymer chains having an overall 1,2-microstructure, assigned as a percentage per unit based on a total polyene content of approximately 10-80%, and optionally, approximately 25-65%, may be desirable for certain end-use applications. Based on the total polyene content, polymers having 1,2-microstructure at about 50% or less, preferably about 45% or less, more preferably about 40% or less, even more preferably about 35% or less, and most preferably about 30% or less, are considered "substantially linear".

[0022] While certainly not necessary and undesirable, terminal active polymers are vinyl aromatics, particularly C8-C8.20 It is not excluded from including directly bonded pendant aromatic groups provided by mer units derived from vinyl aromatics, such as styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, etc. The microstructure of such interpolymers can be random, i.e., the mer units derived from each type of constituent monomer do not form blocks, but rather are incorporated in an essentially non-repeating manner. Random microstructures may offer certain advantages in some end-use applications, such as rubber compositions used in the manufacture of tire treads.

[0023] Solution polymerization has been practiced since around the mid-20th century, and its general forms are known to those skilled in the art. Nevertheless, certain forms are provided here for convenience of reference.

[0024] Polar solvents such as THF or nonpolar solvents can be used in solution polymerization, with the latter being more common in industrial implementations. Examples of nonpolar solvents typically used in anionically initiated solution polymerization include various C5-C 12 Examples include cyclic and acyclic alkanes and their alkylated derivatives, certain liquid aromatic compounds, and mixtures thereof. Those skilled in the art will recognize other useful solvent options and combinations.

[0025] In solution polymerization, both randomization and vinyl content (i.e., 1,2-microstructure) can be increased by including coordinators, usually polar compounds, in the polymerization components. For example, depending on the desired vinyl content, the level of non-polyene monomer used, the reaction temperature, and the characteristics of the specific coordinator used, up to 90 or more equivalents of coordinator per equivalent of initiator can be used. Useful compounds as coordinators include organic compounds containing heteroatoms with non-bonding electron pairs, particularly O or N. Examples include dialkyl ethers of mono- and oligoalkylene glycols; crown ethers; tertiary amines such as tetramethylethylenediamine; THF; THF oligomers; linear and cyclic oligomer oxolanyl alkanes such as 2,2-bis(2'-tetrahydrofuryl)propane, di-piperidylethane, hexamethylphosphoramide, N,N'-dimethylpiperazine, diazabicyclooctane, diethyl ether, and tributylamine (see, for example, U.S. Patent No. 4,429,091).

[0026] Those skilled in the art will understand the conditions typically used in solution polymerization; however, for the convenience of the reader, a representative explanation is provided. The following is based on a batch process, but can be easily extended to, for example, a semi-batch or continuous process. Depending on the properties of the desired polymer, specific conditions for solution polymerization can vary considerably.

[0027] Typically, solutions of polymerization solvents and monomers are provided at temperatures of approximately -70° to +150°C, more commonly, approximately -40° to +120°C, and typically, approximately 0° to 100°C.

[0028] An initiating compound is added to this solution. Examples of initiators include organolithium compounds, particularly alkyllithium compounds. Examples of organolithium initiators include N-lithio-hexamethyleneimine; n-butyllithium; tributyltinlithium; dialkylaminolithium compounds such as dimethylaminolithium, diethylaminolithium, dipropylaminolithium, and dibutylaminolithium; dialkylaminoalkyllithium compounds such as diethylaminopropyllithium; and C1-C 12 Preferably, examples include trialkylstanyl lithium compounds containing C1-C4 alkyl groups.

[0029] Polyfunctional initiators, i.e., initiators capable of forming polymers having two or more living ends, can also be used. Examples of polyfunctional initiators, but are not limited to, include 1,4-dilithiobutane, 1,10-dilithiodecane, 1,20-dilithioeicosane, 1,4-dilithiobenzene, 1,4-dilithionaphthalene, 1,10-dilithioanthracene, 1,2-dilithio-1,2-diphenylethane, 1,3,5-trilithiopentane, 1,5,15-trilithioeicosane, 1,3,5-trilithiocyclohexane, 1,3,5,8-tetralithiodecane, 1,5,10,20-tetralithioeicosane, 1,2,4,6-tetralithiocyclohexane, and 4,4'-dilithiobiphenyl.

[0030] In addition to organolithium initiators, so-called functional initiators can also be useful. These are incorporated into polymer chains and, consequently, provide functional groups to the initiated ends of the chains. Examples of such materials include lithiated arylthioacetals (see, for example, U.S. Patent No. 7,153,919) and reaction products of organolithium compounds with N-containing organic compounds such as substituted aldimines, ketimines, and secondary amines pre-reacted with compounds such as diisopropenylbenzene, which are optionally pre-reacted (see, for example, U.S. Patents No. 5,153,159 and 5,567,815). For example, the use of N-containing initiators such as lithiated HMIs can further enhance the interaction between polymer chains and carbon black particles. See also, for example, U.S. Patents No. 8,227,562, 8,871,871, 9,365,660, 10,277,425, and 10,815,328.

[0031] After introducing the starting compound, polymerization is allowed to proceed under anhydrous anaerobic conditions for a period sufficient to bring about the formation of the desired polymer, typically about 0.01 to 100 hours, more commonly about 0.08 to 48 hours, and typically about 0.15 to 2 hours.

[0032] Once the desired polymerization rate is reached, the heat source (if used) can be removed, and if the reaction vessel was prepared solely for polymerization, the reaction mixture is transferred to a post-polymerization vessel for further reaction.

[0033] Polymers fabricated using anionic technology generally have a number-average molecular weight (M) of up to approximately 500,000 Daltons. n ) has. In a particular embodiment, M n It may be as low as about 2000 Daltons, and in these and / or other embodiments, M nis advantageously at least about 10,000 Daltons, or can be in the range of about 50,000 to about 250,000 Daltons, or about 75,000 to about 150,000 Daltons. Preferred ranges are from about 75,000 to about 225,000 Daltons, particularly from about 100,000 to about 200,000 Daltons. In many cases, M n is typically such that the cooled sample exhibits a Mooney viscosity (ML4 / 100°C) of from about 2 to about 150, more generally from about 2.5 to about 125, even more generally from about 5 to about 100, and most generally from about 10 to about 75.

[0034] The functionalized EPDM and the carbanion polymer can be reacted at a temperature of from 10 to 600 minutes, from about 0° to about 150°C, more generally from about -10° to about 100°C, and typically from about 20° to about 80°C. It is preferred to maintain anaerobic and anhydrous conditions to maintain the activity of the carbanion polymer chains, but no catalyst is required.

[0035] As will be understood by those skilled in the art, the amount of grafting can be controlled using the amount of functionalized EPDM chains and the ratio of EPDM to the carbanion polymer. In addition, although less preferred, an active H atom-containing compound can be introduced into the carbanion polymer solution to reduce the number of living chains.

[0036] The resulting polymer, i.e., the grafted EPDM, typically has an M n of from about 500 to about 1250 kg / mol, and in many cases from about 550 to about 1100 kg / mol. Nevertheless, a very large number of grades of EPDM are available and the molecular weight of the anionic-initiated polymer can be varied very easily, so the foregoing ranges are merely illustrative and should not be considered limiting.

[0037] The polymers, though not limited to natural or synthetic polyisoprene (NR preferred), and a wide variety of other polymers including polyenes, particularly dienes, and even homopolymers and interpolymers of conjugated dienes, can be used as components in vulcanizable compositions. Exemplary conjugated dienes include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,2-butadiene, 1,3-pentadiene, and 1,3-hexadiene, with 1,3-butadiene being particularly preferred. BR having a 1,2-vinyl content of 3% or less and at least 96 cis-1,4 content is preferred. BR with a maximum 1,2-content of approximately 12% can also be used, with appropriate adjustments to the levels of other components. (In this paragraph, all percentages are in moles, and such percentages are determined by various spectroscopic techniques.)

[0038] Interpolymers of a conjugated diene monomer and at least one monoolefin may also be included. Potentially useful monoolefin monomers include vinyl aromatic compounds (e.g., styrene, α-methylstyrene, vinylnaphthalene, vinylpyridine, etc.) and α-olefins (e.g., ethylene and propylene), as well as mixtures thereof. Such interpolymers may contain up to 50%, preferably about 35% or less (both w / w) of the monoolefin merm. A preferred interpolymer of this type is SBR.

[0039] The rubber composition may also contain non-grafted EPDM. Any of the various grades that differ in terms of molecular weight, ethylene-to-propylenemer content, and specific types of diene monomers can be used. Despite the inclusion of such other types of EPDM, the advantage of the above polymers is that the total amount of EPDM contained in the rubber composition can be reduced while still providing an acceptable level of crack resistance. Specifically, the total amount of EPDM contained in such a composition is less than about 25% of the weight of all polymers used in the composition, generally less than 20%, typically less than 18%, preferably less than 15%, more preferably less than 13%, and most preferably less than 12%. In terms of range, the total amount of EPDM can be 5-22%, generally 6-19%, typically 7-17%, more typically 8-16%, and most typically 9-15%.

[0040] Any other polymers can be used in appropriate amounts, provided that the resulting rubber composition does not impede the ability of the resulting rubber composition to provide a vulcanized product with the desired physical properties. Non-limiting examples include butyl rubber, neoprene, EPR, acrylonitrile / butadiene rubber, silicone rubber, fluoroelastomers, ethylene / acrylic rubber, EVA, epichlorohydrin rubber, chlorinated polyethylene rubber, chlorosulfonated polyethylene rubber, hydrogenated nitrile rubber, and tetrafluoroethylene / propylene rubber.

[0041] The types of polymers described above can be compounded in particular with reinforcing fillers. Elastomer compounds are typically filled such that the volume fraction obtained by dividing the total volume of added filler by the total volume of the elastomer stock is often about 25%, and the typical (combined) amount of reinforcing filler is in the range of about 30 to about 100 phr, with the upper limit of the range being mainly defined by how effectively the processing equipment can handle the increased viscosity imparted when such fillers are used.

[0042] Useful fillers include, but are not limited to, various forms of carbon black, including furnace black, channel black, and lamp black. More specifically, examples of carbon black include ultra-abrasive furnace black, high-abrasive furnace black, high-speed extrudeable furnace black, fine furnace black, semi-abrasive furnace black, semi-reinforced furnace black, moderately processable channel black, difficult-to-process channel black, conductive channel black, and acetylene black, and mixtures of two or more of these may be used. At least 20 m 2 / g, preferably at least about 35m 2 Carbon black having a surface area (EMSA) of 1 / g is preferred; for a method to determine the surface area of ​​carbon black, please refer to ASTM D-1765. The carbon black may be in pellet form or in non-pelletized cotton-like form, but non-pelletized carbon black may be preferred for use in certain mixers.

[0043] The amount of carbon black can be up to approximately 50 phr, but is typically around 5 to 40 phr.

[0044] Amorphous silica (SiO2) can be used as a packing material. Silica is generally produced by chemical reactions in water and precipitates as ultrafine spherical particles, and is therefore classified as wet or hydrated silica. These primary particles strongly aggregate to form aggregates, and these aggregates then bond together with relatively weak forces to form granular masses. "Highly dispersible silica" is any silica that has a very high ability to disassemble and disperse in an elastomeric matrix, and can be observed by thin-section microscopy.

[0045] Surface area is a reliable indicator of the reinforcing properties of various silicas, and the Brunauer, Emmet, and Teller ("BET") method (described in J.Am.Chem.Soc., vol.60, p.309 et seq.) is an accepted method for determining surface area. The BET surface area of ​​silica is generally 450 m². 2 Less than / g, generally about 32 to 400m 2 / g, or approximately 100-250m 2 / g, or approximately 150-220m 2 It is / g.

[0046] The pH of the silica packing material (when used) is generally about 5 to about 7 or slightly higher, preferably about 5.5 to about 6.8.

[0047] When silica is used, coupling agents such as silanes are added to ensure good mixing and interaction with the elastomer. Generally, the amount of silane added ranges from about 4 to 20%, based on the weight of the silica filler present in the elastomeric compound. The coupling agent may have the general formula ATG, where A represents a functional group that can physically and / or chemically bond with a group on the surface of the silica filler (e.g., a surface silanol group), T represents a hydrocarbon group bond, and G represents a functional group that can bond with the elastomer (e.g., via a sulfur-containing bond). Examples of such coupling agents include organosilanes, particularly polysulfide alkoxysilanes (see, for example, U.S. Patents No. 3,873,489, 3,978,103, 3,997,581, 4,002,594, 5,580,919, 5,583,245, 5,663,396, 5,684,171, 5,684,172, 5,696,197, etc.) or polyorganosiloxanes having the G and A functional groups described above. The addition of processing aids can be used to reduce the amount of silane used. For a description of fatty acid esters of sugars used as processing aids, see U.S. Patent No. 6,525,118. Useful additional fillers as processing aids include, but are not limited to, mineral fillers such as clay (hydrated aluminum silicate), talc (hydrated magnesium silicate), and mica, as well as non-mineral fillers such as urea and sodium sulfate. Exemplary mica mainly contains alumina, silica, and potassium carbonate, but other varieties may also be used. Additional fillers can be used in quantities up to approximately 40 phr, typically up to approximately 20 phr.

[0048] Silica is generally used in amounts of up to approximately 100 phr, typically around 5 to 80 phr. When carbon black is also present, the amount of silica can be reduced to about 1 phr, and if the amount of silica is reduced, a smaller amount of processing aid, including silane if available, can be used.

[0049] One or more novel fillers having a relatively high interfacial free energy, i.e., a surface free energy value (γpl) in water, can be used with or instead of carbon black and / or silica. The term "relatively high" means, for example, that the γ of amorphous silica is greater than the value at the water-air interface, preferably several times this value (e.g., at least 2 ×, at least 3 ×, or even more than 4 ×). pl At least several times the value (for example, at least 2x, at least 3x, at least 4x, at least 5x, at least 6x, at least 7x, at least 8x, at least 9x, or even more than 10x), absolutely, for example, at least about 300, at least about 400, at least about 500, at least about 600, at least about 700, at least about 750, at least about 1000, at least about 1500, and at least about 2000 mJ / m 2 These can be defined or characterized in various ways. Non-limiting examples of naturally occurring materials with relatively high interfacial free energy include F-apatite, goethite, hematite, zincite, blackite, gibbsite, quartz, kaolinite, and all forms of pyrite. Certain synthetic composite oxides can also exhibit this type of high interfacial free energy.

[0050] The aforementioned types of materials are typically denser than either carbon black or amorphous silica. Therefore, replacing a given mass of carbon black or silica with an equal mass of an unconventional filler will typically result in a much smaller total volume of filler present in the given compound. Consequently, the replacement is typically based on equal volume rather than equal weight.

[0051] Other conventional rubber additives may be added. These include, for example, process oils, plasticizers, antioxidants and ozone degradation inhibitors, curing agents, and so on. Advantageously, the rubber composition according to the present invention does not need to contain a large amount of antioxidants / ozone degradation inhibitors to provide a vulcanized product with an appropriate level of ozone resistance.

[0052] All components can be mixed using standard equipment, such as a Banbury or Brabender mixer. Mixing is typically carried out in two or more stages. During the first stage (often referred to as the masterbatch stage), mixing usually begins at a temperature of about 120-130°C and increases until it reaches the so-called temperature drop, usually around 165°C.

[0053] When the formulation contains fillers other than carbon black, or in addition to carbon black, a separate re-grinding step is often used for each separate addition of silane components. This step is often performed at a temperature similar to that used in the masterbatch stage, but often slightly lower, i.e., from approximately 90°C to approximately 150°C.

[0054] The reinforced rubber compound is cured by conventional methods with one or more known vulcanizing agents, such as sulfur or peroxide-based curing agents, at a rate of approximately 0.2 to 5 phr. For a general disclosure of suitable vulcanizing agents, interested readers should refer to the overview provided in Kirk-Othmer, Encyclopedia of Chem.Tech., 3d ed., (Wiley Interscience, New York, 1982), vol 20, pp. 365-468. The vulcanizing agent, accelerator, etc., are added in the final mixing stage. To reduce unwanted scorching and / or premature onset of vulcanization, this mixing step is often carried out at a low temperature, for example, starting at approximately 60° to 65°C and not exceeding a temperature of approximately 105° to 110°C.

[0055] Subsequently, the compounded mixture is processed into sheets (e.g., milled) and then vulcanized before being formed into any of the various components. This vulcanization is typically carried out at a temperature about 5° to 15°C higher than the highest temperature used during the mixing stage, most commonly at about 170°C.

[0056] As is evident from the preceding explanation, overall preferences regarding features, scope, numerical limitations, and embodiments can be combined to a practical extent with other such generally preferred features, scope, and numerical limitations, provided they do not interfere or are incompatible. The embodiments listed below are provided to assist in considering some of such combinations.

[0057] Process Embodiment P1. A process for providing a polymer comprising graft chains containing EPDM and polyemmer, comprising reacting functionalized EPDM with a carbanion polymer containing polyemmer, wherein the functional groups of the functionalized EPDM are reactive to carbanions. P2. The process described in P1, wherein the functional group is an epoxy group. P3. The process described in P2, wherein the functionalized EPDM is a reaction product of EPDM and m-chloroperoxybenzoic acid. P4. The process according to any one of P1 to P3, wherein the carbanion polymer consists of a polyemer. P5. A process described in any one of P1 to P4, wherein the polyene is a conjugated diene. P6. Carbanion polymers are 50-250 kg / mol M n A process described in any one of P1 to P5, having the following characteristics. P7. Carbanion polymers are 100-200 kg / mol M n The process described in P5, which has the following characteristics.

[0058] Polymer Embodiments M1. A polymer containing graft chains containing EPDM and polyemer. M2. A polymer as described in M1, wherein the graft chains consist of polyemer. M3. A polymer according to M1 or M2, wherein the polyene is a conjugated diene. M4. The graft chain has a molecular weight of 50-250 kg / mol. n A polymer having any one of M1 to M3. M5. The graft chain has a concentration of 100-200 kg / mol. n A polymer as described in M4, having the properties of M4. M6.400~1500 kg / mol n A polymer having any one of M1 to M5. M7,500~1250 kg / mol n A polymer having the properties described in M6.

[0059] Examples of rubber compounds A rubber composition containing a polymer including graft chains containing R1.EPDM and polyemer. R2. The rubber composition according to R1, wherein the composition does not contain other polymers including polyemer. R3. The rubber composition according to R1 or R2, wherein the total amount of EPDM in the composition is 15 phr or less. R4. A rubber composition of R3 in which the total amount of EPDM in the composition is 10 phr or less. R5. Polymers are M 400-1500 kg / mol n A rubber composition according to any one of R1 to R4, having the properties of R1 to R4.

[0060] Vulcanized products supplied from any of R1 to R5 are also intended.

[0061] The following non-limiting and exemplary examples provide detailed conditions and materials that may be useful in carrying out the present invention. These examples use 1,3-butadiene as exemplary polyene due to various factors including cost, availability, ability to handle, and, most importantly, the ability to perform internal comparisons as well as comparisons with previously reported polymers. Those skilled in the art can extend these examples to polymers prepared from a variety of other polyenes. [Examples]

[0062] In the following examples, the n-butyllithium (n-BuLi) solution is 1.6 M, and the 2,2-bis(2'-tetrahydrofuryl)propane (BTHFP) solution is 1.6 M, both in hexane.

[0063] The molecular weight (all in kg / mol) of the polymer samples was determined by GPC using THF as the solvent and calibrated with a series of polystyrene standards. The styrene and 1,2-linkage (vinyl) content of the polymer samples was determined by NMR spectroscopy, while the glass transition temperature (T) was determined. g The value was determined by DSC.

[0064] Examples 1-2: BR In a 7.5 L (2 gallon) N2-purged reactor equipped with a stirrer, 1.16 kg of hexane and 3.27 kg of 1,3-butadiene solution (20.8% w / w in hexane) were added, followed by the addition of 0.14 mL of BTHFP solution and 3.62 mL of n-BuLi solution. The reactor jacket was heated to 65°C.

[0065] The batch temperature peaked at 99.8°C.

[0066] Approximately 60 minutes later, the required amount of polymer cement was filled into the bottles used in Examples 4-7 below, and the remainder was added dropwise to approximately 4 L of a mixture of 0.002 g of 2,6-di-tert-butyl-4-methylphenyl (BHT) per 1 mL of isopropanol.

[0067] The above was repeated, with the only difference being that the batch temperature peaked at 98.3°C. This material is designated as Example 2 below.

[0068] Example 3: Epoxy-coated EPDM A glass bottle containing 20g of EPDM was purged with N2 for 30 minutes, and then 400mL of THF was added to it.

[0069] After standing overnight, the bottle was stirred at 65°C for approximately 6 hours, and then 1.86 g of meta-chloroperoxybenzoic acid was added. The contents of the bottle were stirred using a magnetic stirrer at room temperature for approximately 210 minutes.

[0070] The polymer cement was solidified in an isopropanol solution, washed twice with isopropanol, and then dried in a vacuum oven at 45°~50°C for approximately 14 hours (yield 85.9%).

[0071] For use in the following grafting examples, 15 g of recovered EPDM polymer was added to an N2-purged glass bottle, followed by the addition of 300 mL of cyclohexane. After the polymer dissolved, 20 g of orange silica gel was added to prepare a solution of epoxidized EPDM (6.8% (w / w) in cyclohexane). The contents were magnetically stirred at room temperature until most of the bubbles disappeared, and then the contents were transferred to a new N2-purged bottle to remove the silica gel.

[0072] Examples 4-11: Grafting Four bottles containing 19 mL of the purified epoxidized EPDM solution from Example 2 were purged with N2 for approximately 30 minutes. 31 mL of the polymer cement product from Example 1 was added to each bottle.

[0073] No additional n-BuLi solution was added to the bottle designated as Example 4. The following amounts of additional n-BuLi solution were added to the other three bottles. Example 5 - 0.04 mL Example 6 - 0.10 mL Example 7 - 0.20 mL

[0074] After shaking each bottle well (by hand), let it stand overnight.

[0075] The following day, 0.5 mL of isopropanol was added to each bottle, and the polymer cement was allowed to solidify in the isopropanol solution, followed by two washes with isopropanol.

[0076] Each polymer cement was dried in a vacuum oven at 45° to 50°C for 6 hours.

[0077] The GPC data for polymers from Examples 1 and 3-7 are shown in the table below, with all molecular weights expressed in kg / mol. EPDM (Example 3) does not have a first peak, but after grafting with BR, the resulting grafted polymer product exhibits a first peak. The amount of grafted polymer product can then be estimated using the ratio of the first peak to the second peak.

[0078] [Table 1]

[0079] The polymers from Examples 5-7 exhibited a higher first-to-second-peak ratio, suggesting that the addition of at least some additional initiators during grafting may improve grafting efficiency. (This may simply be due to the additional initiators removing residual moisture and active H-containing materials such as isopropanol.)

[0080] In addition to the above, the solution from Example 3 and the cement from Example 2 were used in further reactions, and the information regarding these is shown in the table below. Each bottle was shaken by hand for several minutes, then left to stand for 2 days, followed by quenching (0.5 mL isopropanol), solidification in isopropanol solution, washing with isopropanol (twice), and drying in a vacuum oven (45°C to 50°C for 6 hours).

[0081] [Table 2]

[0082] The GPC data for the polymers from Example 2 and Examples 8-11 are shown in the table below. (Data for Example 3 can be found in Table 1 above.) All molecular weights are expressed in kg / mol. Regarding percentages, "BR%" represents the weight percentage of the total polymer attributable to the 1,3-butadiemer, while the three percentages below represent the weight percentages of the ungrafted polymers (BR and EPDM, respectively) and the grafted polymers. (The sum of the last three numbers is 100 and is rounded to the nearest whole number.)

[0083] [Table 3]

[0084] Examples 12-19: Rubber compositions and vulcanized products Various polymers were mixed during the masterbatch stage, while the same type and amount of additives and curing agents were mixed during the final stage. The mill temperature at both stages was 65°C. (EPDM is a commercially available material.)

[0085] Green rubber is cured at 171°C to provide a vulcanized material for physical testing.

[0086] Ozone tolerance data was collected using instruments provided by Corporate Consulting Service & Instruments, Inc. (Akron, Ohio). Each test specimen (75 mm × 12 mm × 2 mm) was set to 20% strain and 40°C for 140 hours, with the ozone concentration maintained at 0.5 ppm during measurement. Each sample was assigned a grade based on the following scale: Ap No cracks B = crack C=Damaged near the clip D=damaged

[0087] [Table 4]

[0088] The comparative vulcanized products (Examples 12-15) required 25% (w / w) of EPDM before cracking was no longer observed. Conversely, each of the BR-grafted EPDM-containing vulcanized products (Examples 16-19) received the same grade even though they contained significantly less EPDM than the comparative example in Example 15.

[0089] Although not bound by theory, vulcanized products prepared from compositions containing BR-grafted EPDM (Examples 16-19) were found to have much smaller EPDM domains (i.e., better dispersion) than the vulcanized product of Comparative Example 13 when subjected to transmission electron microscopy. This disclosure includes the following embodiments. <1> A polymer containing graft chains made of EPDM and polyemer. <2> The graft chain is made of a polyemer, <1> The polymers described above. <3> The polyene is a conjugated diene. <1> or <2> The polymers described above. <4> The aforementioned graft chain has a molecular weight of 50-250 kg / mol. n Having the above <1> or <2> The polymers described above. <5> The aforementioned graft chain has a molecular weight of 100-200 kg / mol. n Having the above <4> The polymers described above. <6> M 400-1500 kg / mol n Having the above <1> or <2> The polymers described above. <7> M 500-1250 kg / mol n Having the above <6> The polymers described above. <8> A method for providing a polymer comprising graft chains containing EPDM and polyemmer, wherein the method comprises reacting functionalized EPDM with a carbanion polymer containing polyemmer, wherein the functional groups of the functionalized EPDM are reactive to carbanions. <9> The functional group is an epoxy group, and the epoxy group is optionally provided by the reaction of EPDM with m-chloroperoxybenzoic acid. <8> Methods used. <10> The carbanion polymer is made of a polyemer, <8> or <9> Methods used. <11> The polyene is a conjugated diene. <8> or <9> Methods used. <12> The carbanion polymer is 50-250 kg / mol M n Having the above <11> Methods used. <13> The carbanion polymer is M100-200 kg / mol n Having the above <12> Methods used. <14> A rubber composition comprising a polymer containing EPDM and a polyemer-containing graft chain, wherein the composition optionally does not contain other polymers containing polyemer. <15> The aforementioned polymer is M, which has a concentration of 400-1500 kg / mol. n Having the above <14> The rubber composition described above. <16> The total amount of EPDM in the composition is 15 phr or less. <14> or <15> The rubber composition described above. <17> The total amount of EPDM in the composition is 10 phr or less. <16> The rubber composition described above.

Claims

1. A polymer comprising EPDM and a graft chain containing a butadiemer, The aforementioned graft chain has a molecular weight of 50-250 kg / mol. ｎ It has, The EPDM is a functionalized EPDM containing epoxy functional groups, The graft chain is bonded to the EPDM via the functional group. Polymer.

2. M ｎ The polymer according to claim 1, having the properties of

3. A method for providing a polymer comprising EPDM and a graft chain containing a butadiemer, wherein the method comprises reacting functionalized EPDM with a carbanion polymer containing a butadiemer, and the functional group of the functionalized EPDM is an epoxy group.

4. The method according to claim 3, wherein the functional group is provided by the reaction of EPDM with m-chloroperoxybenzoic acid.

5. A tire sidewall comprising a rubber composition comprising a reinforcing filler and a polymer comprising graft chains containing EPDM and butadiemer, The rubber composition optionally does not contain other polymers including polyemer. The EPDM is a functionalized EPDM containing epoxy functional groups, The graft chain is bonded to the EPDM via the functional group. Tire sidewall.

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