Controlled molecular weight distribution of isobutylene-co-p-methylstyrene elastomer compositions and methods related thereto

Abstract

A method of controlling the molecular weight distribution of an elastomeric composition, in particular an isobutylene-co-p-methylstyrene elastomer composition, in particular for a tire composition such as an inner liner. At least the first and second isobutyl-co-p-methylstyrene compositions are blended together, and the blended isobutyl-co-p-methylstyrene composition has a blended molecular weight distribution of greater than or equal to about 2.5.

Description

[0001] Inventor :Sunny Jacob;Zaccheus M.Mokua;CaolP.Huff

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 405,926, filed September 13, 2022, entitled CONTROLLED MOLECULAR WEIGHTDISTRIBUTION OF ISOBUTYLENE-CO-PARAMETHYLSTYRENE ELASTOMER COMPOSITIONS AND METHODS RELATED THERETO, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0004] The present invention relates to a method for controlling the molecular weight distribution of an elastomeric composition, and in particular to a method for broadening the molecular weight distribution of an isobutylene-co-p-methylstyrene elastomer composition. Background Art

[0005] Tires contain many rubber compounds and other materials, and they need to operate safely in various harsh conditions for vehicles such as passenger vehicles, trucks, buses and airplanes. It is expected that they will continue to operate for thousands of miles while maintaining their basic performance and safety properties. Tire performance depends at least in part on their ability to retain air or inflation pressure. Butyl rubbers such as isobutylene-co-p-methylstyrene elastomers are particularly suitable for air retention and can be formulated for specific tire applications (such as innerliners, i.e., the innermost layer of tires). Select a specific butyl rubber composition used as an innerliner, including additional additives, to reach suitable properties related to processability and uncured and cured physical properties (which include mechanical strength, surface appearance and joint integrity). Several factors can affect these properties.

[0006] Molecular weight distribution (MWD = Mw / Mn), also known as the polydispersity index, has a significant impact on the mechanical and physical bulk properties of the polymer and the resulting compounded product, including those that are integral to making a commercially viable tire innerliner - processability and uncured versus cured physical properties. For innerliner applications, butyl rubber compound Mooney viscosity and Mooney relaxation are important to producing a rubber with innerliner bonding characteristics that result in suitable bond strength integrity after cure. A balance of MWD in butyl rubber (high molecular weight butyl rubber versus low molecular weight butyl rubber) is required to achieve these properties while maintaining processability; the high molecular weight portion contributes to mechanical properties such as tensile break, elongation, impact strength, etc., while the low molecular weight portion contributes to processability factors such as low melt viscosity, plasticizer quality, etc. Therefore, a broad MWD of butyl rubber is important for producing commercially viable tire innerliners and ultimately finished tire products.

[0007] Butyl rubber polymerization is conventionally carried out using suitable monomers and Lewis acid catalysts (and initiators). However, widespread inconsistency in the MWD of butyl rubber throughout the tire industry has been previously documented. It has also been observed that currently produced innerliner tire products generally exhibit narrow MWD. ​​As described above, narrow MWD can lead to processing difficulties and / or undesirable physical and mechanical properties.

[0008] The present disclosure provides methods and systems for producing isobutylene-co-p-methylstyrene elastomer compositions having controlled MWD, particularly isobutylene-co-p-methylstyrene elastomer compositions having relatively broadened MWD. Summary of the invention

[0009] In a non-limiting aspect of the present disclosure, a method is provided, the method comprising blending at least a first isobutylene-co-p-methylstyrene composition and a second isobutylene-co-p-methylstyrene composition to produce a blended isobutylene-co-p-methylstyrene composition. The blended isobutylene-co-p-methylstyrene composition has a blend molecular weight distribution greater than or equal to about 2.5.

[0010] In a non-limiting aspect of the present disclosure, a method is provided, the method comprising polymerizing a first polymerization medium in a reactor, the first polymerization medium comprising a first isobutylene monomer, a first p-methylstyrene monomer, a first diluent, and a first catalyst system, wherein the first catalyst system comprises a first Lewis acid and a first initiator, thereby producing a first isobutylene-co-p-methylstyrene composition; and polymerizing a second polymerization medium in a reactor, the second polymerization medium comprising a second isobutylene monomer, a second p-methylstyrene monomer, a second diluent, and a second catalyst system, wherein the second catalyst system comprises a second Lewis acid and a second initiator, thereby producing a second isobutylene-co-p-methylstyrene composition. The first isobutylene-co-p-methylstyrene composition and the second isobutylene-co-p-methylstyrene composition are blended to produce a blended isobutylene-co-p-methylstyrene composition, and the blended isobutylene-co-p-methylstyrene composition has a blended molecular weight distribution greater than or equal to about 2.5.

[0011] These and other features and attributes of the disclosed controlled MWD methods and systems for producing the isobutylene-co-p-methylstyrene elastomer compositions of the present disclosure, as well as their advantageous applications and / or uses, will become apparent from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] To assist one of ordinary skill in the relevant art in making and using the subject matter herein, reference is made to the accompanying drawings. The following figures are included to illustrate certain aspects of the present disclosure, and these figures should not be construed as exclusive configurations. The disclosed subject matter is capable of considerable modification, alteration, combination, and equivalence in form and function, as will occur to one skilled in the art having the benefit of this disclosure.

[0013] Figure 1 is a schematic flow diagram of a simplified aggregation system 100 according to one or more aspects of the present disclosure.

[0014] Figure 2 is a schematic diagram of the bromination reaction of isobutylene-co-p-methylstyrene polymer according to one or more aspects of the present disclosure.

[0015] Figure 3 and 4 A blending scheme for producing a blended isobutylene-co-p-methylstyrene polymer according to one or more aspects of the present disclosure.

[0016] Figure 5 is a graph showing the MWD of control and blended isobutylene-co-p-methylstyrene polymers according to one or more aspects of the present disclosure.

[0017] Figure 6is a graph showing the MWD of control and blended isobutylene-co-p-methylstyrene polymers according to one or more aspects of the present disclosure. DETAILED DESCRIPTION

[0018] The present application relates to a method for controlling the molecular weight distribution of an elastomeric composition, and in particular to a method for broadening the molecular weight of an isobutylene-co-p-methylstyrene elastomeric composition.

[0019] The present disclosure provides methods for controlling the MWD of isobutylene-co-p-methylstyrene elastomer compositions by blending two or more polymers. In particular, the present disclosure provides controlled MWD broadening by blending two or more isobutylene-co-p-methylstyrene polymers in a specific ratio to obtain a determined molecular weight and MWD. ​​In one or more aspects, the resulting broadened isobutylene-co-p-methylstyrene composition can be further functionalized, for example, by halogenation (e.g., bromination).

[0020] In various aspects of the present disclosure, separate isobutylene-co-p-methylstyrene polymers are prepared in separate polymerization reactors and blended in a finishing step, such as in a mixing drum. One or more of the separate isobutylene-co-p-methylstyrene polymers may be brominated prior to blending. Each of the separate isobutylene-co-p-methylstyrene polymer compositions has a known MWD and other known properties such as Mooney viscosity. In one or more alternative aspects of the present disclosure, separate isobutylene-co-p-methylstyrene polymers may be polymerized in two or more reactors in series. For example, polymerization may be initiated in a first reactor and at a predetermined time, the resulting partially polymerized medium is fed to a second reactor to continue polymerization to allow polymer chain growth, optionally followed by bromination after the desired MWD is reached.

[0021] The resulting blended isobutylene-co-p-methylstyrene polymer compositions of the present disclosure can have any desired MWD, but preferably have a broadened MWD of greater than or equal to about 2.5.

[0022] definition

[0023] As used herein, the term "catalyst system" and its grammatical variants refer to and include any Lewis acid (one or more) or other metal complex (one or more) and optionally at least one initiator for catalyzing the polymerization of hydrocarbon monomers. Other additives such as catalyst modifiers may be included. The catalyst system is combined with a diluent for polymerization, collectively referred to as a "polymerization medium." As used herein, "polymerization system" and its grammatical variants refer to the use of a polymerization medium to produce a polymer.

[0024] As used herein, the term "diluent" and grammatical variations thereof refer to a diluting or dissolving agent, including mixtures thereof (eg, two or more separate diluents). When the diluent acts as a diluting agent it may also be used to affect reactor agitation.

[0025] As used herein, the term "solvent" and grammatical variations thereof refer to a chemical agent that can dissolve the produced polymer.

[0026] As used herein, "reactor" and its grammatical variants refer to any container (one or more) in which a chemical reaction (e.g., polymerization) occurs. Examples of butyl polymerization reactors include continuous flow stirred tank reactors using continuous kettles, and draft tube reactors (draft tube type reactors). Various cooling jackets, pipelines, etc. can be used in combination with reactors (or can be integrated with reactors) to control or otherwise maintain reactor temperature during polymerization. Commercial reactors can generally be well-mixed containers with a volume greater than 10 to 500 liters (excluding jackets) with a high circulation rate provided by a pump impeller. Both polymerization and pumps can generate heat and in order to keep the slurry cool, the reaction system can include a heat exchanger. In some reactors, the slurry can be circulated through the tubes of the heat exchanger. Cooling can be provided, for example, by evaporating ethylene on the shell side. The slurry temperature can be set by the temperature of boiling ethylene, the required heat flux, and the overall heat transfer resistance.

[0027] As used herein, the term "slurry" and grammatical variations thereof refer to an amount of diluent comprising polymer precipitated from the catalyst system and the diluent. The slurry concentration is the weight percentage of partially or fully precipitated polymer based on the total slurry.

[0028] As used herein, the term "quench" and grammatical variations thereof refer to the process of rapidly heating a reactor effluent stream and mixing it with a quench medium, thereby terminating further polymerization.

[0029] As used herein, the term "polymer" and its grammatical variants refer to homopolymers, copolymers, interpolymers, terpolymers, and the like. The term "copolymer" and its grammatical variants are meant to include polymers having two or more monomers. The term "interpolymer" and its grammatical variants are meant to include polymers having two or more monomers. The term "interpolymer" and its grammatical variants are meant to be any polymer or oligomer having a number average molecular weight of 500 or greater prepared by polymerization or oligomerization of at least two different monomers. As used herein, when a polymer is referred to as "comprising" a monomer, the monomer is present in the polymer in the polymerized form of the monomer or in the form of a derivative of the monomer.

[0030] The term "functionalized" and its grammatical variations refer to a polymer to which a functional group is chemically bonded. The term "functional group" and its grammatical variations may refer to halides, activated esters, anhydrides, thiols, ketones, epoxides, etc. Of particular interest to the present disclosure are halide or halogen functionalizations.

[0031] As used herein, the term "olefin" and its grammatical variations refer to hydrocarbons containing a carbon-carbon double bond. "Isoolefin" and its grammatical variations refer to any olefin monomer having two substituents on the same carbon.

[0032] As used herein, "elastomer" or "elastomeric composition" and grammatical variations thereof refer to any polymer or composition of polymers that conforms to the definition of ASTM D1566, Revision 21A (November 2021). Elastomer may be used interchangeably herein with the term "rubber(s)".

[0033] As used herein, "Mooney viscosity" and its grammatical variants are the Mooney viscosity of a polymer or polymer composition. The polymer composition analyzed to determine the Mooney viscosity should be substantially free of diluent. For example, the sample can be placed in a boiling water steam table cover to evaporate most of the diluent and unreacted monomers, then dried in a vacuum oven overnight (12 hours, 90°C), and then tested according to laboratory analytical techniques, or the sample for testing can be taken from a devolatilized polymer (i.e., devolatilization after the polymer in an industrial scale process). Unless otherwise indicated, the Mooney viscosity is measured using a Mooney viscometer according to ASTM D1646-19A (November 2019), but the following modifications / clarifications of the procedure are used. First, the sample polymer is pressed between two hot plates of a compression press before testing. The plate temperature is 125°C + / - 10°C instead of 50 + / - 5°C recommended in ASTM D1646-17, because 50°C does not cause sufficient aggregation. Additionally, although ASTM D1646-17 allows for several options for mold protection, if any two options provide conflicting results, PET 36 microns is used as mold protection. Additionally, ASTM D1646-17 does not specify sample weight in Section 8; therefore, given that results may vary based on sample weight, the Mooney viscosity determined according to the D1646-17 Section 8 procedure using a sample weight of 21.5 + / - 2.7 grams (g) is used. Finally, the pre-test quiescent procedure specified in D1646-17 Section 8 is 23 + / - 3°C in air for 30 minutes; the Mooney values ​​reported herein are determined after quiescent at 24 + / - 3°C in air for 30 minutes. According to the ASTM D1646-17 test method, the sample is placed on both sides of the rotor; the Mooney viscosity is determined by measuring the torque required to turn the viscometer motor at 2 rpm using a sensor. Results are reported in Mooney units (ML, 1+4 at 125°C or ML, 1+8 at 125°C), where MU is the Mooney viscosity number, L represents the large rotor (defined as ML in ASTM D1646-17), 1 is the warm-up time in minutes, 4 or 8 is the sample run time in minutes after the motor is started, and 125°C is the test temperature. Thus, a Mooney viscosity of 90 determined by the above method is reported as a Mooney viscosity of 90MU (ML, 1+8 at 125°C) or 90MU (ML, 1+4 at 125°C). Alternatively, the Mooney viscosity may be reported as 90MU; in such cases, it should be assumed that such viscosity was determined using the method just described (ML, 1+4 at 125°C), unless otherwise indicated. In some cases, a lower test temperature (e.g., 100°C) may be used, in which case the Mooney is reported as the Mooney viscosity (ML, 1+8 at 100°C) or at T°C, where T is the test temperature.

[0034] As used herein, the term "Mooney relaxation" or "Mooney stress relaxation" and grammatical variations thereof refer to the response of an elastomer (e.g., isobutylene-co-p-methylstyrene) to rapid cessation of flow or sudden deformation and is dependent on the Mooney viscosity. Mooney relaxation is determined according to ASTM D1646-17.

[0035] Numerical ranges used herein include the values ​​recited in the range. For example, a numerical range of "1 wt % to 10 wt %" includes 1 wt % and 10 wt % within the recited range.

[0036] Aggregation System

[0037] The present disclosure provides methods for controlling the MWD to achieve a desired MWD using post-polymerization blending of two or more isobutylene-co-p-methylstyrene polymer (hereinafter referred to as "polymer") compositions having known MWD. ​​In one or more aspects described herein, the present disclosure provides a blending method to achieve improved processability by broadening the MWD compared to conventional isobutylene-co-p-methylstyrene polymers, such as for use in the manufacture of tire innerliners. In one or more aspects, the resulting blended isobutylene-co-p-methylstyrene polymer composition has an MWD greater than or equal to about (hereinafter referred to as "about") 2.5, including an MWD in the range of about 2.5 to about 5.0, covering any value and subsets therebetween, such as about 2.5 to about 3.5, or about 3.5 to about 4.5, or about 4.5 to about 5.0, or about 2.5 to about 3.0, or 2.6 to 3.75 MWD.

[0038] Before describing the methods of the present disclosure in further detail, a brief overview of a generalized example polymerization system for producing isobutylene-co-p-methylstyrene elastomer is provided so that various aspects of the present disclosure may be better understood, including the additional blending configurations that will be described and depicted herein.

[0039] The polymerization system for producing isobutylene-based elastomers, such as isobutylene-co-p-methylstyrene elastomer, is typically carried out using a continuous slurry polymerization system, wherein the polymerization reactor temperature is below 0° C., such as in the range of about −105° C. to about 0° C. However, it should be understood that a batch or reactor series polymerization system may be used in accordance with one or more aspects described herein without departing from the scope of the present disclosure.

[0040] Reference now Figure 1, which is a schematic flow diagram of a polymerization system 100 according to one or more aspects of the present disclosure. Catalyst system 102 and monomer 104 are fed into polymerization reactor 108. In some cases, catalyst system 102 and monomer 104 may be blended in a blending device (not shown) and then fed into polymerization reactor 108. In addition, in some cases, if necessary, monomer 104 may be treated to remove impurities before being introduced into polymerization reactor 108 (or blending device). For the production of isobutylene-co-p-methylstyrene, monomer 104 comprises C 4 -C 7 Isoolefins are isobutylene (hereinafter referred to as "isobutylene") and paramethylstyrene (hereinafter referred to as "p-methylstyrene").

[0041] The catalyst system 102 and the monomer 104 may be fed simultaneously or separately to the polymerization reactor 108, for example, by one or more pump impellers (not shown). The monomer 104, alone or in combination with the catalyst system 102, is fed to the polymerization reactor 108 at a temperature below 0°C. The catalyst system 102 and the monomer 104, including the components of the catalyst system 102 (e.g., Lewis acid(s) and initiator(s)), are mixed within the polymerization reactor 108 and may initially exist as a single phase dissolved in the diluent 106, which is also fed simultaneously or separately. The diluent 106 serves to dissolve the catalyst system 102 and the monomer 104 without dissolving the polymerization product (polymer) and thus causing them to precipitate and form a slurry. When one or more input materials are fed simultaneously to the polymerization reactor 108, a single pump impeller may be used. The one or more pump impellers are typically capable of either or both of upward pumping or downward pumping (i.e., bidirectional pumping) and often include an electric motor with a measurable amperage. The pump impeller serves to maintain a continuous flow of monomer, catalyst system and diluent, including reacted and unreacted materials (eg, monomer), within the reactor.

[0042] The polymerization reactor 108 can be any reactor suitable for polymerization to produce an isobutylene-based elastomer. In one or more aspects, the polymerization reactor 108 is a continuous flow tube reactor (daft tube reactor) with a circulation pump 108a built into the overflow pipe for efficient stirring. Typically, the polymerization reactor 108 is equipped with an external cooling jacket 108c and associated internal cooling (or heat exchange) pipes to remove the heat generated during polymerization and maintain the desired reaction temperature. In one or more aspects, the cooling pipe can contain liquid ethylene to remove heat from the polymerization reaction.

[0043] In one or more aspects, the polymerization reactor can have a volume in the range of about 425 liters (L) to about 500 L (including any values ​​and subsets therebetween), including the jacket and associated internal cooling pipes, and can be larger by about 50 L if the jacket is not included. The volume is conducive to large-scale volume polymerization reactions according to various aspects described herein. Therefore, reactors with larger volumes (and smaller volumes, although less preferred) can be used to facilitate scale-up without departing from the scope of the present disclosure.

[0044] Typically, the polymerization temperature within the polymerization reactor 108 for producing the isobutylene-based elastomer of the present disclosure is in the range of about -105°C to about 0°C, or -100°C to -50°C, or -98°C to -92°C, etc., preferably 0°C to the freezing point of the polymerization medium, such as the diluent and monomer mixture, and the reaction is then quenched by adding a quenching agent to the polymerization medium.

[0045] During polymerization, the catalyst system 102 and the monomer 104 react and the produced polymer precipitates from the diluent 106. A reactor effluent stream 110 comprising polymer (produced during polymerization), the diluent 106, unreacted monomer 104, and unreacted catalyst system 102 exits the reactor from the reactor outlet. For an isobutylene-based elastomer polymerization system 100, the reactor effluent stream 110 may be warmed to room temperature (RT) or heated, for example, from a temperature at or below 0°C (within the polymerization reactor 108) to, for example, a temperature in the range of about -50°C to about 20°C (including any values ​​and subsets therebetween).

[0046] The unreacted catalyst system 102 in the reactor effluent stream 110 may form undesirable substances that interfere with downstream processing of the polymer produced during polymerization (e.g., functionalization thereof). During warming or heating, but before heating above about -50°C to about 20°C, the reactor effluent stream 110 may be quenched 118. The quenching serves to terminate the reactivity of all unreacted catalyst systems 102 (i.e., the catalyst (s) in the catalyst system 102) before any significant warming or heating of the reactor effluent stream 110, so as to prevent continued polymerization and crosslinking reactions (which may interfere with downstream processing) from occurring as the reactor effluent stream 110 is heated. Conventional quenchers include steam and / or hot water introduced into the reactor effluent stream 110. Other conventional quenchers include linear or branched alcohols, such as ethanol, tert-butyl alcohol, methanol, triethylene glycol (TEG), and any combination thereof. During the quench, the reactor effluent stream 110 can be combined with a solvent 116 to dissolve and fractionate the desired polymer in the reactor effluent stream 110 for downstream processing 120 (e.g., halogenation and additional blending with other polymer streams) (e.g., for forming an isobutylene-co-p-methylstyrene polymer composition having a desired MWD according to the present disclosure), separated from the diluent(s) 106, the solvent(s) 116, and any unreacted monomer 104 or diluent or solvent, to a tank or other storage container (not shown). In one or more aspects of the present disclosure, the contents of the tank can be recycled.

[0047] Polymerization system for controlling MWD (and MRI) of isobutylene-co-p-methylstyrene elastomers

[0048] The method of the present disclosure for producing an isobutylene-co-p-methylstyrene elastomer composition having a controlled MWD generally uses an existing polymerization system, such as reference Figure 1 The present disclosure is directed to a polymerization system described herein, but employs unconventional post-polymerization blending of two or more isobutylene-co-p-methylstyrene elastomer compositions. These blending methods can be advantageously used to widen the MWD of the resulting isobutylene-co-p-methylstyrene elastomer product. Although the present disclosure is described with respect to tire innerliners having a desired wide MWD of an isobutylene-co-p-methylstyrene elastomer, it should be understood that the present disclosure can be applicable to other types of air retention products or can be applicable to other rubber products having a desired wide MWD. ​​That is, the various aspects of the present disclosure can generally be used to control the MWD of an isobutylene-co-p-methylstyrene elastomer without departing from the scope of the present disclosure. In addition, the various aspects described herein can encompass blending of any isobutylene-based elastomer to achieve a desired widened MWD, not just isobutylene-co-p-methylstyrene bodies, without departing from the scope of the present disclosure.

[0049] In one or more aspects, the present disclosure provides a polymerization system for polymerizing a polymerization medium comprising monomers isobutylene and p-methylstyrene, a diluent and a catalyst system to form an isobutylene-co-p-methylstyrene polymer composition. Thereafter, two or more such isobutylene-co-p-methylstyrene polymer compositions are blended in a specific ratio to achieve a desired broadened MWD. ​​In optional aspects, one or more of such isobutylene-co-p-methylstyrene polymer compositions may be brominated or halogenated prior to blending.

[0050] For preparing the isobutylene-co-p-methylstyrene body composition for blending disclosed herein, the monomers used for polymerization include isobutylene and p-methylstyrene. Isobutylene and p-methylstyrene may be present in equal or unequal amounts without departing from the scope of the present disclosure.

[0051] In one or more aspects, the monomers (total) can be present in the polymerization medium in an amount from about 30 weight percent (wt%) to about 40 wt%, e.g., from about 30 wt% to about 35 wt%, or in the range of about 35 wt% to about 40 wt%, encompassing any values ​​and subsets therebetween.

[0052] In one or more aspects of the present disclosure, the isobutylene-co-p-methylstyrene polymer produced comprises from about 80 mole percent (mol%) to about 99.5 mol% isobutylene, encompassing any values ​​and subsets therebetween, such as from about 80 mol% to about 90 mol%, or from about 90 mol% to about 99.5 mol% isobutylene; and comprises from 0.5 mol% to about 20 mol% p-methylstyrene, encompassing any values ​​and subsets therebetween, such as from about 0.5 mol% to about 5 mol%, or from about 0.5 mol% to about 10 mol%, or from about 5 mol% to about 10 mol%, or from about 10 mol% to about 20%.

[0053] The diluent or solvent, or a mixture thereof, is selected so that the catalyst dissolves in the catalyst system and the monomer(s) and precipitates the polymerization product (polymer) - isobutylene-co-p-methylstyrene. An acceptable relatively low viscosity polymerization medium is obtained so that the heat of polymerization can be removed more effectively by surface heat exchange. Suitable solvents include organic compounds, especially those having an affinity for hydrocarbon fluids. Examples of solvents suitable for use in the present disclosure include, but are not limited to, hydrocarbons, such as hexane, heptane, halogenated hydrocarbons, such as chlorinated hydrocarbons, such as ethyl chloride, methyl chloride, CHCl 3 , CCl 4 , n-butyl chloride, chlorobenzene, etc., and any combination thereof. In one or more aspects of the present disclosure, the selected solvent is methyl chloride, dichloromethane or hexane. For example, methyl chloride is a commercially acceptable solvent due to its suitable freezing point and boiling point.

[0054] According to one or more aspects of the present disclosure, a solvent such as methyl chloride or hexane is selected for the polymerization system described herein to control the molecular weight and advantageously can achieve an isobutylene-co-p-methylstyrene elastomer polymer product concentration in the range of about 20 volume percent (volume %) to about 60 volume %, encompassing any values ​​and subsets therebetween, such as about 20 volume % to about 50 volume %, or about 30 volume % to about 35 volume %, or about 18 volume % to about 28 volume %, or about 24 volume % to about 27 volume %. Among other factors, the amount of solvent can be adjusted according to one or more aspects of the present disclosure to adjust the viscosity of the polymerization medium.

[0055] Catalyst system of the present disclosure comprises lewis acid (one or more) or metal complex (one or more) and initiator.Before introducing monomer (one or more), lewis acid (one or more) or metal complex (one or more) are contacted with each other for a period of time, in one or more aspects, for at least several hours, for example, from about 0.5 second to about 5 hours, or from about 0.5 second to about 2 hours, or from about 0.5 second to about 30 minutes in the range, covering any value and subset therebetween.In some aspects, the contact time between lewis acid (one or more) or metal complex (one or more) and initiator is from about 0.5 second to about 5 minutes or from about 1 second to about 5 minutes in the range, covering any value and subset therebetween.In other aspects again, lewis acid (one or more) or metal complex (one or more) and initiator can be separately sent to reactor, therefore do not have predetermined contact time.

[0056] The purpose of Lewis acid (one or more) or metal complex (one or more) is to catalyze polymerization to produce isobutylene-co-p-methylstyrene elastomer. Lewis acids based on aluminum can be used in various aspects of the present disclosure. Suitable examples of Lewis acids based on aluminum include, but are not limited to, aluminum chloride, aluminum bromide, ethylaluminum dichloride (EADC), sesquiethylaluminum chloride, diethylaluminum chloride, methylaluminum dichloride, sesquimethylaluminum chloride, dimethylaluminum chloride, etc., and any combination thereof alone or with other suitable Lewis acids. Other suitable examples include Lewis acids based on boron, such as boron trifluoride, and Lewis acids based on titanium, such as titanium tetrachloride, etc., and any combination thereof alone or with other suitable Lewis acids. In exemplary aspects of the present disclosure, the selected Lewis acid (one or more) includes Lewis acids based on aluminum.

[0057] In one or more aspects, the Lewis acid(s) and the initiator can be present in the polymerization system described herein in a molar ratio ranging from about 1.0 to about 10.0 (ratio of Lewis acid(s) to initiator), with any values ​​and subsets therebetween being encompassed, for example, from about 1.0 to about 2.5, or from about 2.5 to about 5.0, or from about 5.0 to about 7.5, or from about 7.5 to about 10.0. Such ratios are equally applicable to any other Lewis acid(s) or metal complex(s) to initiator ratios, as described herein, without departing from the scope of the present disclosure.

[0058] A variety of initiators can be used in the polymerization system of the present disclosure to control the MWD of the isobutylene-co-p-methylstyrene elastomer, provided that they are compatible with the other components of the polymerization medium. The initiators used in the present disclosure are selected so that they can be complexed with the selected Lewis acid(s) or other metal complex(s) in a suitable diluent to produce a complex that reacts rapidly with the isobutylene and p-methylstyrene monomers to form a growing polymer chain (polymerization). Suitable examples of initiators for use in the present disclosure include, but are not limited to, Bronsted acids such as H 2 O, HCl, RCOOH (wherein R is an alkyl group), alkyl halides such as (CH 3 ) 3 CCl, C 6 H 5 C(CH 3 ) 2 Cl, 2-chloro-2,4,4-trimethylpentane and 2-chloro-2-methylpropane, hydrohalides and any combination thereof. Other suitable initiators may also be used, as known to those skilled in the art.

[0059] In one or more aspects, the selected initiator(s) are diluted in a diluent (e.g., hexane, methyl chloride) to provide a concentration in the polymerization slurry (contents of the reactor) of 1.0 parts per million (ppm) to about 10.0 ppm, encompassing any values ​​and subsets therebetween, such as about 1.0 ppm to about 2.5 ppm, or about 2.5 ppm to about 5.0 ppm, or about 5.0 ppm to about 7.5 ppm, or about 7.5 ppm to about 10.0 ppm, etc. If the catalyst system and monomer reactor feed streams and the diluent feed stream are added separately, they can be adjusted to achieve the desired diluent concentration.

[0060] In one or more aspects, after the polymerization is completed, the isobutylene-co-p-methylstyrene polymer can be present in an amount of about 22 wt % to about 50 wt % of the remaining polymerization slurry (e.g., diluent, unreacted monomer, unreacted catalyst, unreacted initiator), encompassing any values ​​and subsets therebetween, such as about 22 wt % to about 30 wt %, or about 30 wt % to about 40 wt %, or about 40 wt % to about 50 wt %. The specific reactor residence time to achieve the desired isobutylene-co-p-methylstyrene body concentration is not particularly limited and depends on several factors, such as catalyst activity and concentration, monomer concentration, feed injection (flow) rate, production rate, reaction temperature, desired molecular weight, etc. The feed injection rate of the monomer can have the greatest impact on the residence time. Typically, in aspects of the present disclosure, the reactor residence time is in the range of about 10 minutes (min) to about 60 min, encompassing any values ​​and subsets therebetween, such as about 10 min to about 20 min, or about 20 min to 30 min, or about 30 min to about 40 min, or about 40 min to about 50 min, or about 50 min to about 60 min. Thereafter, as described above, the polymerization slurry leaves the reactor and the pump impeller can continue to fill the reactor for continued polymerization without departing from the scope of the present disclosure.

[0061] The isobutylene-co-p-methylstyrene polymers of the present disclosure have an average molecular weight distribution of about 2.5 and typically have a molecular weight (Mw) in the range of about 200,000 to about 2,000,000, encompassing any values ​​and subsets therebetween, such as about 200,000 to about 500,000, or about 500,000 to about 1,000,000, or about 1,000,000 to about 1,500,000, or about 1,500,000 to about 200,000.

[0062] The isobutylene-co-p-methylstyrene polymers produced according to the present disclosure may be halogenated and particularly brominated in one or more aspects. The polymer may be brominated as described in U.S. Patent No. 5,162,445, which is incorporated herein by reference in its entirety. The bromination of the isobutylene-co-p-methylstyrene polymers of the present disclosure includes substitutions occurring almost exclusively on the para-methyl group to obtain the desired benzylic bromine functionality. The high specificity of the bromination reaction can be maintained under a wide range of reaction conditions, but the prerequisite is to avoid factors that promote the reverse reaction route. Typically, bromination is a free radical bromination.

[0063] The isobutylene-co-p-methylstyrene polymers described herein are brominated in a hydrocarbon solvent such as pentane, hexane or heptane using light, heat or a selected free radical initiator (depending on the conditions, i.e., a specific free radical initiator must be selected with a half-life suitable for the specific temperature conditions used, generally longer half-lives are preferred at warmer hydrogenation temperatures) as a promoter for free radical halogenation to produce the desired benzylic bromine functionality almost exclusively via substitution on the para-methyl group without significant chain scission and / or crosslinking. Without being bound by any theory, it is believed that the bromination reaction proceeds by way of a rapid free radical chain reaction, wherein the chain carrier is alternatively a benzylic group and a bromine atom generated by abstraction of a hydrogen atom from a para-methyl group on the p-methylstyrene moiety on the chain. The proposed mechanism thus includes Figure 2 The reaction terminates when one of the free radicals reacts with a quencher in the system (or is quenched), or when the free radical eliminates itself by recombination or disproportionation.

[0064] Reference Figure 2 , the reaction can be initiated by forming bromine atoms photochemically or thermally (with or without a sensitizer) as shown in step (1), or the free radical initiator used can be an initiator that preferentially reacts with bromine molecules rather than non-selectively with bromine atoms, or with solvents or polymers (e.g., via hydrogen abstraction). The photochemical sensitizer preferably absorbs lower energy photons and dissociates by itself, thereby in turn causing the dissociation of bromine (including materials such as iodine). In one or more aspects, the free radical initiator has a half-life in the range of about 0.5 min to about 2500 min under the desired reaction conditions, covering any value and subset therebetween, such as about 0.5 min to 500 min, or about 500 min to about 1000 min, or about 1000 min to about 1500 min, or about 1500 min to about 2000 min, or about 2000 min to about 25500 min. In some aspects, the free radical initiator has a half-life in the range of about 10 min to about 300 min, encompassing any values ​​and subsets therebetween.

[0065] The amount of free radical initiator used for bromination can be in the range of about 0.02% to about 1.0% by weight of the isobutylene-co-p-methylstyrene polymer, for example, about 0.02% to about 0.1% by weight, or about 0.1% to about 0.5% by weight, or about 0.5% to about 1.0% by weight. In some aspects, the amount of free radical initiator is in the range of about 0.02% to about 0.3% by weight of the isobutylene-co-p-methylstyrene polymer, encompassing any values ​​and subsets therebetween.

[0066] Suitable free radical initiators include, but are not limited to, bis-azo compounds such as azobisisobutyronitrile, azobis(2,4-dimethylvalero)nitrile, azobis(2-methylbutyro)nitrile, and the like, and any combination thereof. Other free radical initiators may also be used, but it is preferred to use a free radical initiator with relatively weak hydrogen abstraction ability so that it reacts preferentially with bromine molecules to form bromine atoms rather than with isobutylene-p-methylstyrene or solvent to form alkyl radicals. In such cases, it tends to cause molecular weight loss of the isobutylene-co-p-methylstyrene body and promote undesirable side reactions such as crosslinking. The free radical bromination reaction used in the present disclosure is highly selective and almost exclusively produces the desired benzylic bromine functionality. In fact, the only major side reaction that may occur is disubstitution at the para-methyl group to produce a dibromo derivative, but even so, this side reaction will not occur until more than about 60% of the p-methylstyrene moieties on the chain have been monosubstituted. Thus, any desired amount of benzylic bromine functionality in monobrominated form can be introduced into the isobutylene-co-p-methylstyrene bodies of the present disclosure, up to about 60 mole % of the p-methylstyrene content. In addition, because the p-methylstyrene content can be varied within the generally wide ranges described herein, a wide range of functionality can be additionally introduced. The brominated isobutylene-co-p-methylstyrene polymers of the present disclosure are therefore very useful in subsequent reactions such as crosslinking reactions (e.g., for forming tire innerliners).

[0067] It is desirable that the termination reaction discussed above be minimized during bromination, so that long, rapid free radical chain reactions occur, and so that each initiation introduces a lot of benzylic bromine, while minimizing the side reactions caused by termination. Therefore, system purity is important, and the steady-state free radical concentration must be kept low enough to avoid a large amount of recombination and possible crosslinking. Once the bromine is consumed, the bromination reaction must also be quenched so that continued free radical generation and resulting secondary reactions (in the absence of bromine) do not occur or are minimized. Quenching can be accomplished by cooling, turning off the light source, adding a dilute base, adding a free radical scavenger, or the like, or a combination thereof.

[0068] Since each mole of bromine that reacts with or replaces the p-methylstyrene moiety on the chain produces one mole of hydrogen bromide (HBr), it is desirable in one or more aspects to neutralize or otherwise remove the HBr during the reaction or at least during polymer recovery to prevent it from participating in or catalyzing undesirable side reactions. Such neutralization and removal can be accomplished using a post-reaction caustic wash, typically using a base in molar excess to the HBr. Alternatively, neutralization can be accomplished by making a specific base (which is relatively non-reactive with bromine) such as calcium carbonate powder (present in dispersed form during the bromination reaction) absorb the HBr as it is produced. Removal of HBr can also be accomplished by using an inert gas (e.g., N 2 ) is preferably accomplished by stripping at elevated temperature.

[0069] The brominated, quenched and neutralized isobutylene-co-p-methylstyrene polymer described herein is recovered and can be stabilized using a suitable stabilizer (eg, bistetrazole, calcium stearate, etc.) and then further processed to broaden the MWD as described herein.

[0070] Method for controlling the MWD of isobutylene-co-p-methylstyrene elastomer

[0071] In one or more aspects of the present invention, a method is provided comprising post-polymerization blending of two or more isobutylene-co-p-methylstyrene polymer compositions (each having a known MWD) to achieve a broadened MWD. ​​Advantageously, it has been found that as provided herein, a broadened MWD can be achieved compared to that expected from the isobutylene-co-p-methylstyrene polymer composition alone or by simple combination, which, without being bound by theory, is believed to be at least due to different Mooney viscosities. The Mooney viscosity can be controlled by controlling the feed ratio of the catalyst system to the monomers.

[0072] In various aspects of the present disclosure, one or more of the isobutylene-co-p-methylstyrene polymer compositions may be brominated or halogenated to improve certain properties of the polymer, such as mechanical or chemical properties.

[0073] The widened MWD is achieved by blending various isobutylene-co-p-methylstyrene polymer compositions in a certain ratio so as to achieve an MWD greater than about 2.5. The resulting wide MWD is particularly advantageous for forming one or more rubber product components, such as tire components, including inner liners. Other applicable end-use rubber products include, but are not limited to, rubber devices (usually air retention), such as inner tubes, tire bladders, tire sidewalls, rubber plugs (e.g., medical plugs), etc. and any combination thereof. The blending ratio can depend on several factors, including but not limited to the MWD of each (two or more) individual isobutylene-co-p-methylstyrene polymer composition, the Mooney viscosity of each (two or more) individual isobutylene-co-p-methylstyrene polymer composition, the Mooney relaxation of each (two or more) individual isobutylene-co-p-methylstyrene polymer composition, and any combination thereof. The Mooney viscosity of the isobutylene-co-p-methylstyrene polymer composition alone can be in the range of about 20 MU to about 70 MU, encompassing any values ​​and subsets therebetween, such as about 30 MU to about 40 MU, or about 40 MU to about 50 MU, or about 50 MU to about 60 MU, or about 60 MU to about 70 MU.

[0074] The blending described herein can occur in various reactors and mixing configurations provided herein after polymerization of a separate isobutylene-co-p-methylstyrene polymer composition. The blending of at least two isobutylene-co-p-methylstyrene compositions can be in the range of about 10:90 to about 90:10, encompassing any values ​​and subsets therebetween, such as about 10:90 to about 70:30, or about 10:90 to about 50:50, or about 10:90 to about 20:80, or about 20:80 to about 90:10, or about 40:60 to about 60:40.

[0075] Methods of controlling the MWD of isobutylene-co-p-methylstyrene elastomers are further described below with reference to the non-limiting examples described herein.

[0076] Example Implementation

[0077] Non-limiting example embodiments of the present disclosure include:

[0078] Embodiment A: A method comprising: blending at least a first isobutylene-co-p-methylstyrene composition and a second isobutylene-co-p-methylstyrene composition to produce a blended isobutylene-co-p-methylstyrene composition, wherein the blended isobutylene-co-p-methylstyrene composition has a blend molecular weight distribution greater than or equal to about 2.5.

[0079] Embodiment B: A method comprising: polymerizing a first polymerization medium in a reactor, the first polymerization medium comprising a first isobutylene monomer, a first p-methylstyrene monomer, a first diluent, and a first catalyst system, wherein the first catalyst system comprises a first Lewis acid and a first initiator, thereby producing a first isobutylene-co-p-methylstyrene composition, polymerizing a second polymerization medium in a reactor, the second polymerization medium comprising a second isobutylene monomer, a second p-methylstyrene monomer, a second diluent, and a second catalyst system, wherein the second catalyst system comprises a second Lewis acid and a second initiator, thereby producing a second isobutylene-co-p-methylstyrene composition, blending the first isobutylene-co-p-methylstyrene composition and the second isobutylene-co-p-methylstyrene composition to produce a blended isobutylene-co-p-methylstyrene composition, wherein the blended isobutylene-co-p-methylstyrene composition has a blended molecular weight distribution greater than or equal to about 2.5.

[0080] Embodiment C: A method comprising: polymerizing a first polymerization medium in a first reactor, the first polymerization medium comprising a first isobutylene monomer, a first para-methylstyrene monomer, a first diluent, and a first catalyst system, wherein the first catalyst system comprises a first Lewis acid and a first initiator, thereby producing a first isobutylene-co-p-methylstyrene composition; polymerizing a second polymerization medium in a second reactor, the second polymerization medium comprising a second isobutylene monomer, a second para-methylstyrene monomer, a second diluent, and a second catalyst system, wherein the second catalyst system comprises a second Lewis acid and a second initiator, thereby producing a second isobutylene-co-p-methylstyrene composition; wherein the first reactor and the second reactor are separate, and polymerizing the first polymerization medium and polymerizing the second polymerization medium are separately conducted in parallel; and blending the first isobutylene-co-p-methylstyrene composition and the second isobutylene-co-p-methylstyrene composition to produce a blended isobutylene-co-p-methylstyrene composition, wherein the blended isobutylene-co-p-methylstyrene composition has a blended molecular weight distribution greater than or equal to about 2.5.

[0081] Non-limiting example embodiment A may include one or more of the following elements:

[0082] Element A1: wherein the blended molecular weight distribution of the blended isobutylene-co-p-methylstyrene composition is in the range of about 2.5 to about 5.0.

[0083] Element A2: wherein the blended molecular weight distribution of the blended isobutylene-co-p-methylstyrene composition is within the range of 2.6 to 3.75.

[0084] Element A3: wherein the first isobutylene-co-p-methylstyrene composition has a first molecular weight distribution and the second isobutylene-co-p-methylstyrene composition has a second molecular weight distribution, and wherein one or both of the first molecular weight distribution and the second molecular weight distribution are less than the blended molecular weight distribution.

[0085] Element A4: wherein the first isobutylene-co-p-methylstyrene composition has a first molecular weight distribution and the second isobutylene-co-p-methylstyrene composition has a second molecular weight distribution, and wherein one or both of the first molecular weight distribution and the second molecular weight distribution are less than the blended molecular weight distribution, and wherein the first molecular weight distribution and the second molecular weight distribution are the same or different.

[0086] Element A5: wherein the ratio of the first isobutylene-co-p-methylstyrene composition to the second isobutylene-co-p-methylstyrene composition used to produce the blended isobutylene-co-p-methylstyrene composition is in the range of 10:90 to 90:10.

[0087] Element A6: Also includes halogenating the blended isobutylene-co-p-methylstyrene composition.

[0088] Element A7: Also includes halogenating the blended isobutylene-co-p-methylstyrene composition, and wherein the halogenation is a free radical halogenation process.

[0089] Element A8: further comprising halogenating the isobutylene-co-p-methylstyrene composition, and wherein the halogenation comprises bromination.

[0090] Element A9: wherein the blended isobutylene-co-p-methylstyrene composition comprises an isobutylene content in the range of about 80 mole percent (mol %) to about 99.5 mol %, and a p-methylstyrene content in the range of about 0.5 mol % to about 20 mol %.

[0091] Element A10: Also included is the use of the blended isobutylene-co-p-methylstyrene composition to produce a rubber product.

[0092] Element A11: Also included is the use of the blended isobutylene-co-p-methylstyrene composition to make a rubber product, and wherein the rubber product is selected from the group consisting of a tire innerliner, a tire innertube, a tire bladder, a tire sidewall, a rubber plug, and any combination thereof.

[0093] Each of the elements A1 to A11 may be combined in any combination without limitation.

[0094] Non-limiting example embodiment B may include one or more of the following elements:

[0095] Element B1: wherein the blended molecular weight distribution of the blended isobutylene-co-p-methylstyrene composition is in the range of about 2.5 to about 5.0.

[0096] Element B2: wherein the first isobutylene-co-p-methylstyrene composition has a first molecular weight distribution and the second isobutylene-co-p-methylstyrene composition has a second molecular weight distribution, and wherein one or both of the first molecular weight distribution and the second molecular weight distribution are less than the blended molecular weight distribution.

[0097] Element B3: wherein the ratio of the first isobutylene-co-p-methylstyrene composition to the second isobutylene-co-p-methylstyrene composition used to produce the blended isobutylene-co-p-methylstyrene composition is in the range of 10:90 to 90:10.

[0098] Element B4: further comprises halogenating the blended isobutylene-co-p-methylstyrene composition.

[0099] Element B5: further comprising halogenating the blended isobutylene-co-p-methylstyrene composition, and wherein the halogenation comprises bromination.

[0100] Element B6: wherein the blended isobutylene-co-p-methylstyrene composition comprises an isobutylene content in the range of about 80 mole percent (mol %) to about 99.5 mol %, and a p-methylstyrene content in the range of about 0.5 mol % to about 20 mol %.

[0101] Element B7: Also included is the use of the blended isobutylene-co-p-methylstyrene composition to produce a rubber product.

[0102] Element B8: Also included is the use of the blended isobutylene-co-p-methylstyrene composition to manufacture a rubber product, and wherein the rubber product is selected from the group consisting of a tire innerliner, a tire innertube, a tire bladder, a tire sidewall, a rubber plug, and any combination thereof.

[0103] Each of the elements B1 to B8 may be combined in any combination without limitation.

[0104] Non-limiting example embodiment C may include one or more of the following elements:

[0105] Element C1: wherein the first reactor has a first feed stream for a first polymerization medium and the second reactor has a second feed stream for a second polymerization medium, and wherein the first feed stream and the second feed stream are independently controllable.

[0106] Element C2: further comprising storing one or both of the first polymerization medium and the second polymerization medium in a storage tank, wherein the first p-methylstyrene monomer and the second p-methylstyrene monomer have the same or different concentrations in the first polymerization reactor and the second polymerization reactor, or the storage tank.

[0107] Element C3: wherein the blended molecular weight distribution of the blended isobutylene-co-p-methylstyrene composition is in the range of about 2.5 to about 5.0.

[0108] Element C4: wherein the first isobutylene-co-p-methylstyrene composition has a first molecular weight distribution and the second isobutylene-co-p-methylstyrene composition has a second molecular weight distribution, and wherein one or both of the first molecular weight distribution and the second molecular weight distribution are less than the blended molecular weight distribution.

[0109] Element C5: wherein the ratio of the first isobutylene-co-p-methylstyrene composition to the second isobutylene-co-p-methylstyrene composition used to produce the blended isobutylene-co-p-methylstyrene composition is in the range of 10:90 to 90:10.

[0110] Element C6: Also includes halogenating the blended isobutylene-co-p-methylstyrene composition.

[0111] Element C7: Also includes brominating the blended isobutylene-co-p-methylstyrene composition.

[0112] Element C8: wherein the blended isobutylene-co-p-methylstyrene composition comprises an isobutylene content in the range of about 80 mole percent (mol %) to about 99.5 mol %, and a p-methylstyrene content in the range of about 0.5 mol % to about 20 mol %.

[0113] Element C9: Also included is the use of the blended isobutylene-co-p-methylstyrene composition to make a rubber product.

[0114] Each of the elements C1 to C9 may be combined in any combination without limitation.

[0115] In order to promote a better understanding of the embodiments of the present invention, the following examples of preferred or representative embodiments are given. The following examples should in no way be construed as limiting or defining the scope of the present invention.

[0116] Example

[0117] In the following non-limiting examples, four (4) separate isobutylene-co-p-methylstyrene monomers (hereinafter referred to as "IMS" in the examples) - referred to as polymer A, polymer B, polymer C, and polymer D - are composed of isobutylene and p-methylstyrene (hereinafter referred to as "pMS" in the examples) monomers and are polymerized in a reactor using a Lewis acid, an initiator, and a diluent. Before describing the specific methods, the general composition parameters of each of polymers AC will be described. As shown, certain polymers are combined to have the same or different concentrations of p-methylstyrene monomer in the storage tank, or certain polymers can have the same or different concentrations of p-methylstyrene monomer during polymerization.

[0118] Example Polymer A

[0119] Polymer A is prepared according to the method described above. The catalyst system and the monomer feed rate are adjusted to reach an initiator concentration in the range of about 1.5 ppm to about 3.0 ppm in the polymerization reactor. The resulting polymer A contains a pMS content of about 5 weight % (wt%), has a Mooney viscosity of about 65 MU and an MWD of about 2.5. The average molecular weight (Mw) of polymer A is in the range of about 200,000 to about 2,000,000. The prepared polymer A is stored in a storage tank.

[0120] The Mooney viscosity method conditions for Polymer A are provided in Table 1 below. The sample interval was approximately 1 hour. The term "Rx" means reaction.

[0121] Table 1

[0122]

[0123]

[0124] Example Polymer B

[0125] Polymer B is prepared according to the method described above. The catalyst system and the monomer feed rate are adjusted to reach an initiator concentration in the range of about 4.0ppm to about 8.0ppm in the polymerization reactor. The produced polymer B comprises a pMS content of about 5% by weight, has a Mooney viscosity of about 30MU and an MWD of about 2.5. The average molecular weight (Mw) of polymer B is in the range of about 200,000 to about 2,000,000. The prepared polymer B is stored in a storage tank.

[0126] The Mooney viscosity method conditions for Polymer B are provided below in Table 2. The sample interval was approximately 1 hour.

[0127] Table 2

[0128]

[0129] Example Polymer C b

[0130] Polymer C b is a combination of polymer A and polymer B brominated in a ratio of about 20:80. Each of polymer A and polymer B is produced separately and the produced polymerization slurries are mixed in a mixing drum and then stored. It should be understood that in order to mix polymer A and polymer B, they can be produced separately (polymerized in reactors) (and have independent feed streams to each reactor) and stored in separate tanks and then mixed, or produced in parallel and immediately combined in a mixing drum and then placed in a tank, or can be mixed and not placed in a tank, but immediately produce polymer C when brominated. b That is, the resulting mixture of polymer A and polymer B is brominated according to the method described above to produce polymer C b .

[0131] Figure 3 and 4 The blending schemes 300 and 400 are shown respectively. Figure 3 Reactors 301, 303, and 305 each produce polymer B and are mixed with polymer A from storage tank (e.g., cement storage) 309 in mixing drum 307. Thereafter, the blended combination of polymer A and polymer B may be stored in storage tank 311 for a period of time. The mixture of the combination of polymer A and polymer B is then brominated 313 to produce polymer C. b Typically, the number of reactors for producing polymer A and polymer B is determined by the desired blend ratio; for example, a 25:75 blend would require one reactor for producing polymer A and three reactors for producing polymer B; another example, a 75:25 blend would require three reactors for producing polymer A and one reactor for producing polymer B. The monomer feed rate to each reactor can be varied to more precisely control the blend ratio. Alternatively, and referring now to Figure 4 , reactor 401 produces polymer A and reactors 403, 405 and 407 produce polymer B. The contents of each of reactors 401, 403, 405 and 407 are mixed in mixing drum 409 and can be stored in storage tank 411. The combined mixture of polymer A and polymer B is then brominated 413 to produce polymer C. b .

[0132] Example Polymer D

[0133] Polymer D was prepared according to the method described above. The resulting polymer D contained a pMS content of about 10 wt %, had a Mooney viscosity of about 35 MU and a MWD of about 2.5. The average molecular weight (Mw) of polymer D was in the range of about 200,000 to about 2,000,000. The prepared polymer D was stored in a storage tank.

[0134] Broadening polymers A, B and C b Example Blending Method of MWD

[0135] In this example, polymers A, B, C b The combination was performed in a certain ratio to detect the effect of MWD using gel permeation chromatography (GPC) testing. Polymer A and Polymer B were also tested alone as a control. The GPC tested polymers are shown in Table 3 below.

[0136] Table 3

[0137] Polymers for GPC testing Blending ratio (%) Polymer A 100 Polymer B 100 <![CDATA[Polymer C b (B:A)]]> 78:22 Polymer B:Polymer A 80:20 Polymer B:Polymer A 60:40 Polymer B:Polymer A 50:50 Polymer B:Polymer A 40:60 Polymer B:Polymer A 20:80

[0138] The results of the GPC testing of Polymer A and Polymer B and their blends are provided in Table 4 below.

[0139] Table 4

[0140] polymer Blending Mn(kDa) Mw(kDa) Mz(kDa) Mw / Mn Polymer A 100 454.1 1299.4 2320 2.86 Polymer B 100 181 402 688.1 2.22 Polymer B:Polymer A 80:20 213.1 614.4 1537.8 2.88 Polymer B:Polymer A 60:40 237.8 807.9 1949.3 3.40 Polymer B:Polymer A 50:50 276.7 912.8 2075.5 3.30 Polymer B:Polymer A 40:60 262.5 984.1 2142 3.75 Polymer B:Polymer A 20:80 380.6 1150.3 2260.1 3.02

[0141] As shown in Table 4, each of the blended polymer A and polymer B combination has a broader MWD than either polymer A or polymer B alone. Additionally, it should be understood that commercially available isobutylene-co-p-methylstyrene polymers typically have an MWD of less than 2.3, such as in the range of 2.0 to 2.3. Thus, this example shows that blending according to the methods described herein can broaden the resulting MWD. ​​A graphical depiction of the results of Table 4 is provided at Figure 5 middle.

[0142] Polymer C b The results of the GPC testing of (78:22 polymer B to polymer A, then brominated) are provided in Table 5 below.

[0143] Table 5

[0144] polymer Blending Mn(kDa) Mw(kDa) Mz(kDa) Mw / Mn <![CDATA[Polymer C b > 78(B):22(A) 150.8 527.3 1058.3 3.5

[0145] As shown in Table 5, the use of bromination further broadens the MWD compared to the 80:20 blend of Polymer B:Polymer A provided in Table 4. Thus, according to aspects of the present disclosure, halogenation, and in particular bromination, may be further used to broaden the MWD.

[0146] Example Blending Methods for Broadening the MWD of Polymers A and D

[0147] In this example, polymers A and D were combined in a certain ratio to examine the effect of MWD using GPC testing. Polymers A and D were also tested individually as controls. The GPC tested polymers are shown in Table 6 below.

[0148] Table 6

[0149] Polymers for GPC testing Blending ratio (%) Polymer A 100 Polymer D 100 Polymer D:Polymer A 10:90 Polymer D:Polymer A 20:80 Polymer D:Polymer A 30:70 Polymer D:Polymer A 40:60 Polymer D:Polymer A 50:50 Polymer D:Polymer A 60:40 Polymer D:Polymer A 70:30 Polymer D:Polymer A 80:20 Polymer D:Polymer A 90:10

[0150] The results of the GPC testing of Polymer A and Polymer D and their blends are provided in Table 7 below.

[0151] Table 7

[0152]

[0153]

[0154] As shown in Table 4, each of the blended Polymer A and Polymer D combinations has a broader MWD than either Polymer A or Polymer D alone and the commercially available isobutylene-co-p-methylstyrene polymer (MWD less than 2.3). Thus, this example further shows that blending according to the methods described herein can broaden the resulting MWD. ​​A graphical depiction of the results of Table 7 is provided in Figure 6 middle.

[0155] Thus, the present disclosure shows that post-polymerization control and modification of the polymerization system according to one or more methods of the present disclosure can be used to broaden the molecular weight distribution of the produced polymer.

[0156] Unless otherwise indicated, all numerical values ​​expressing quantities of ingredients, properties such as molecular weight, reaction conditions, etc. used in this specification and the associated claims are to be understood as being modified in all instances by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that may vary depending upon the desired properties sought to be obtained by implementations of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed based on the number of reported significant digits and by applying ordinary rounding techniques.

[0157] This paper shows one or more illustrative implementations that incorporate one or more inventive elements. For the sake of clarity, not all physical implementation features are described or shown in the application. It should be understood that in the development of the physical embodiment of one or more elements of the present invention, many specific decisions must be made to achieve the developer's goal, such as meeting system-related, business-related, government-related and other restrictions, which vary with implementation and time. Although the developer's work can be time-consuming, such work is a routine matter for those of ordinary skill in the art who benefit from the disclosure.

[0158] Although the compositions and methods are described herein in terms of "comprising" various components or steps, the compositions and methods may also be "consisting essentially of" or "consisting of" the various components and steps. Therefore, the present invention is well adapted to achieve the objects and advantages mentioned as well as those inherent therein. The specific embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent ways obvious to those of ordinary skill in the art having the benefit of the teachings herein. In addition, no limitation is intended to the details of construction or design shown herein, except as described in the claims below. It is therefore apparent that the specific illustrative embodiments disclosed above may be altered, combined or modified and all such changes are considered to be within the scope and spirit of the present invention. The invention illustratively disclosed herein may be suitably practiced in the absence of any elements not specifically disclosed herein and / or any optional elements disclosed herein. Although the compositions and methods are described in terms of "comprising", "containing", or "including" various components or steps, the compositions and methods may also be "consisting essentially of" or "consisting of" the various components and steps. All numerical values ​​and ranges disclosed above may be changed by a certain amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any numerical value and any included range falling within the range are specifically disclosed. In particular, each range of values ​​disclosed herein ("about a to about b" or equivalent "about a to b" or equivalent "about ab" form) should be understood as each numerical value and range included in the wider range of the listed values. In addition, unless otherwise clearly and clearly defined by the patentee, the terms in the claims have their plain, ordinary meanings. In addition, the indefinite article "a" or "a kind" used in the claims is defined herein as meaning one (kind) or more than one (kind) of the elements introduced therein.

Claims

1. Methods, include: blending at least a first isobutylene-co-p-methylstyrene composition and a second isobutylene-co-p-methylstyrene composition to produce a blended isobutylene-co-p-methylstyrene composition, The blended isobutylene-co-p-methylstyrene composition has a blend molecular weight distribution of greater than or equal to about 2.

5.

2. The method of claim 1, wherein the blended isobutylene-co-p-methylstyrene composition has a blended molecular weight distribution in the range of about 2.5 to about 5.

0.

3. The method of claim 1, wherein the blended molecular weight distribution of the blended isobutylene-co-p-methylstyrene composition is in the range of 2.6 to 3.

75.

4. The method of claim 1, wherein the first isobutylene-co-p-methylstyrene composition has a first molecular weight distribution and the second isobutylene-co-p-methylstyrene composition has a second molecular weight distribution, and wherein one or both of the first molecular weight distribution and the second molecular weight distribution are less than the blended molecular weight distribution.

5. The method of claim 4, wherein the first molecular weight distribution and the second molecular weight distribution are the same or different.

6. The method of claim 1, wherein the ratio of the first isobutylene-co-p-methylstyrene composition to the second isobutylene-co-p-methylstyrene composition used to produce the blended isobutylene-co-p-methylstyrene composition is in the range of 10:90 to 90:

10.

7. The method of claim 1 further comprising halogenating the blended isobutylene-co-p-methylstyrene composition.

8. The process according to claim 7, wherein the halogenation is a free radical halogenation process.

9. The method of claim 7, wherein the halogenation comprises bromination.

10. The method of claim 1, wherein the blended isobutylene-co-p-methylstyrene composition comprises an isobutylene content in the range of about 80 mole percent (mol %) to about 99.5 mol %, and a p-methylstyrene content in the range of about 0.5 mol % to about 20 mol %.

11. The method of claim 1, further comprising using the blended isobutylene-co-p-methylstyrene composition to make a rubber product.

12. The method of claim 11, wherein the rubber product is selected from the group consisting of a tire innerliner, a tire innertube, a tire bladder, a tire sidewall, a rubber plug, and any combination thereof.

13. Methods, include: polymerizing a first polymerization medium in a reactor, the first polymerization medium comprising a first isobutylene monomer, a first p-methylstyrene monomer, a first diluent, and a first catalyst system, wherein the first catalyst system comprises a first Lewis acid and a first initiator, thereby producing a first isobutylene-co-p-methylstyrene composition; polymerizing a second polymerization medium in a reactor, the second polymerization medium comprising a second isobutylene monomer, a second p-methylstyrene monomer, a second diluent, and a second catalyst system, wherein the second catalyst system comprises a second Lewis acid and a second initiator, thereby producing a second isobutylene-co-p-methylstyrene composition; and blending the first isobutylene-co-p-methylstyrene composition and the second isobutylene-co-p-methylstyrene composition to produce a blended isobutylene-co-p-methylstyrene composition; The blended isobutylene-co-p-methylstyrene composition has a blend molecular weight distribution of greater than or equal to about 2.

5.

14. The method of claim 13, wherein the blended isobutylene-co-p-methylstyrene composition has a blended molecular weight distribution in the range of about 2.5 to about 5.

0.

15. The method of claim 13, wherein the first isobutylene-co-p-methylstyrene composition has a first molecular weight distribution and the second isobutylene-co-p-methylstyrene composition has a second molecular weight distribution, and wherein one or both of the first molecular weight distribution and the second molecular weight distribution are less than the blended molecular weight distribution.

16. The method of claim 13, wherein the ratio of the first isobutylene-co-p-methylstyrene composition to the second isobutylene-co-p-methylstyrene composition used to produce the blended isobutylene-co-p-methylstyrene composition is in the range of 10:90 to 90:

10.

17. The method of claim 13, further comprising halogenating the blended isobutylene-co-p-methylstyrene composition.

18. The method of claim 18, wherein halogenating comprises brominating.

19. The method of claim 13, wherein the blended isobutylene-co-p-methylstyrene composition comprises an isobutylene content in the range of about 80 mole percent (mol %) to about 99.5 mol %, and a p-methylstyrene content in the range of about 0.5 mol % to about 20 mol %.

20. The method of claim 13, further comprising using the blended isobutylene-co-p-methylstyrene composition to make a rubber product.

21. Methods, include: polymerizing a first polymerization medium in a first reactor, the first polymerization medium comprising a first isobutylene monomer, a first p-methylstyrene monomer, a first diluent, and a first catalyst system, wherein the first catalyst system comprises a first Lewis acid and a first initiator, thereby producing a first isobutylene-co-p-methylstyrene composition; polymerizing a second polymerization medium in a second reactor, the second polymerization medium comprising a second isobutylene monomer, a second p-methylstyrene monomer, a second diluent, and a second catalyst system, wherein the second catalyst system comprises a second Lewis acid and a second initiator, thereby producing a second isobutylene-co-p-methylstyrene composition; wherein the first reactor and the second reactor are separate, and polymerizing the first polymerization medium and polymerizing the second polymerization medium are separately conducted in parallel; and blending the first isobutylene-co-p-methylstyrene composition and the second isobutylene-co-p-methylstyrene composition to produce a blended isobutylene-co-p-methylstyrene composition, The blended isobutylene-co-p-methylstyrene composition has a blend molecular weight distribution of greater than or equal to about 2.

5.

22. The process of claim 1, wherein the first reactor has a first feed stream for a first polymerization medium and the second reactor has a second feed stream for a second polymerization medium, and wherein the first feed stream and the second feed stream are independently controllable.

23. The method of claim 1, further comprising storing one or both of the first polymerization medium and the second polymerization medium in a storage tank, wherein the first p-methylstyrene monomer and the second p-methylstyrene monomer have the same or different concentrations in the first polymerization reactor and the second polymerization reactor, or the storage tank.

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