In-situ bromine regeneration process for producing brominated butyl elastomers

Abstract

In some embodiments, the method includes introducing an aqueous solution into a first hydrocarbon solvent to form an emulsion, wherein the aqueous solution comprises a solution containing an oxidant and a solution containing a surfactant. The method further includes introducing an adhesive together with the emulsion to form a first mixture within a reactor, wherein the adhesive comprises a butyl rubber elastomer and a second hydrocarbon solvent that is the same as or different from the first hydrocarbon solvent. The method further includes introducing a halogen source together with the first mixture contained within the reactor to form a second mixture comprising a halogenated butyl rubber elastomer. The method further includes introducing a neutralizing agent together with the second mixture to form a third mixture. The method further includes isolating the halogenated butyl rubber elastomer from the third mixture.

Description

[0001] Inventors: Sunny Jacob; Joseph D. Penney; Matthew Konderson; Jacob Hay; Darryl Averette; Joseph A. Maier; Yan-Ping He and Eric J. Wamsley

[0002] This application claims the benefit of U.S. Provisional Patent Application 63 / 598,689, filed November 14, 2023, entitled “In-situ Bromine Regeneration Method for the Production of Brominated Butyl Elastomers,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to a method for forming halogenated butyl elastomers. Background Technology

[0004] Several methods for in-situ bromine regeneration using oxidants in the production of brominated butyl rubber have been disclosed. When compared to conventional bromination methods, brominated butyl rubber produced using these regeneration methods (where the byproduct hydrogen bromide (HBr) is converted in situ to molecular bromine, for example using hydrogen peroxide, hypochlorite, etc.) exhibits unacceptable Mooney growth levels during warehouse aging. It has also been observed that the Mooney growth of brominated butyl rubber produced via bromine regeneration methods can be inhibited using certain antioxidants. However, some of these antioxidants are either color-enhancing or lack economic justification for use in typical brominated butyl rubber applications.

[0005] There is still a need to improve the Mooney stability of brominated butyl elastomers, and there is still a need for regenerative halogenation methods in which the resulting polymers exhibit reduced Mooney viscosity growth produced by the regeneration method.

[0006] References cited in the disclosure statement (37C.FR1.97(h)): ExxonMobil Ref. No. 2022EM136 (not yet published); U.S. Publication No. 2018 / 0334555. Summary of the Invention Invention Overview

[0008] This application relates to a method for forming halogenated butyl elastomers.

[0009] In some embodiments, the method includes introducing an aqueous solution into a first hydrocarbon solvent to form an emulsion, wherein the aqueous solution comprises a solution containing an oxidant and a solution containing a surfactant. The method further includes introducing an adhesive into the emulsion to form a first mixture within a reactor, wherein the adhesive comprises a butyl rubber elastomer and a second hydrocarbon solvent that is the same as or different from the first hydrocarbon solvent. The method further includes introducing a halogen source into the first mixture contained within the reactor to form a second mixture comprising a halogenated butyl rubber elastomer. The method further includes introducing a neutralizing agent together with the second mixture to form a third mixture. The method further includes isolating the halogenated butyl rubber elastomer from the third mixture.

[0010] In some embodiments, the method includes introducing an aqueous solution together with a first organic solvent to form an emulsion, wherein the aqueous solution contains an oxidant and a surfactant; the method further includes introducing an adhesive together with the emulsion to form a first mixture and containing the first mixture within a reactor, wherein the adhesive contains a butyl rubber elastomer and a second hydrocarbon solvent. The method further includes introducing a halogen source into the first mixture contained within the reactor to form a second mixture, wherein the formation of the second mixture further includes performing a halogenation reaction. The halogenation reaction includes reacting the halogen source with the butyl rubber elastomer to form an initial halogenated butyl rubber elastomer and a hydrogen halide, reacting the hydrogen halide with the oxidant to form a free halide, and continuing the halogenation reaction to produce additional halogenated butyl rubber elastomers. The method further includes introducing a neutralizing agent together with the second mixture to form a third mixture. The method further includes isolating the initial halogenated butyl rubber elastomer and / or additional halogenated butyl rubber elastomers from the third mixture.

[0011] In some embodiments, the method includes introducing an aqueous solution into a first hydrocarbon solvent to form an emulsion, wherein the aqueous solution contains an oxidant and a surfactant. The method further includes introducing an adhesive into the emulsion to form a first mixture within a reactor, wherein the adhesive contains a butyl rubber elastomer and a second hydrocarbon solvent that is the same as or different from the first hydrocarbon solvent. The method further includes introducing HBr into a reactor containing the first mixture to form a second mixture containing a halogenated butyl rubber elastomer. The method further includes introducing a neutralizing agent together with the second mixture to form a third mixture. The method further includes isolating the halogenated butyl rubber elastomer from the third mixture.

[0012] In some embodiments, the method includes introducing an aqueous solution together with a first organic solvent to form an emulsion, wherein the aqueous solution comprises an oxidant and a surfactant. The method further includes introducing an adhesive together with the emulsion to form a first mixture in a reactor, wherein the adhesive comprises a butyl rubber elastomer and a second organic solvent. The method further includes introducing a halogen source together with the first mixture contained in the reactor to form a second mixture such that the molar ratio of oxidant to halogen is about 0.2:1 to about 0.8:1. Forming the second mixture further includes carrying out a halogenation reaction comprising reacting the halogen source with the butyl rubber elastomer to form an initial halogenated butyl rubber elastomer and a hydrogen halide, reacting the hydrogen halide with the oxidant to form a free halide, and continuing the halogenation reaction to produce additional halogenated butyl rubber elastomer. The method further includes introducing a neutralizing agent together with the second mixture to form a third mixture. The method further includes separating the initial halogenated butyl rubber elastomer and / or the additional halogenated butyl rubber elastomer from the third mixture to form a waste mixture, wherein the waste mixture contains about 2,000 mg / L to about 2,650 mg / L of dissolved solids. Brief description of the attached diagram

[0014] To gain a more detailed understanding of the features listed above in this disclosure, a more specific description of the disclosure, which has been briefly outlined above, can be obtained by referring to some of the aspects shown in the accompanying drawings. However, it should be noted that the drawings illustrate only typical aspects of this disclosure and should not be considered as limiting its scope, as other equally effective aspects are permissible.

[0015] Figure 1 This is a diagram illustrating the formation of butyl rubber according to some embodiments.

[0016] Figure 2 This is a diagram illustrating a solvent displacement process according to some embodiments.

[0017] Figure 3 This is a diagram illustrating the halogenation and neutralization of an adhesive according to some embodiments to form a halogenated butyl rubber.

[0018] Figure 4 This is a diagram illustrating, according to some embodiments, the water / hydrocarbon emulsion flowing from the halogenation and neutralization section to the flash drum.

[0019] Figure 5 This is a diagram illustrating crumb finishing according to some implementation schemes.

[0020] For ease of understanding, the same reference numerals are used where possible to denote the same elements used in the accompanying drawings. The drawings are not drawn to scale and have been simplified for clarity. It is expected that elements and features of one aspect can be advantageously incorporated into other aspects without further description. Invention Details

[0022] This disclosure relates to methods for eliminating or suppressing Mooney viscosity growth (or, in other words, increasing Mooney viscosity stability) over a period of time, which typically occurs in halogenated (brominated) polymers, particularly those prepared using regenerative halogenation (bromination) methods. The regenerative halogenation methods disclosed herein provide halogenated butyl elastomers with Mooney viscosity growth and retention of physical properties comparable to elastomers formed by conventional halogenation methods. In particular, surfactants have been found to promote H₂O₂ conversion during regenerative halogenation by increasing the surface area between the aqueous and organic phases. The methods disclosed herein allow for low residence times and high concentrations of halogenated adhesives without affecting the Mooney stability of the halogenated butyl elastomers. Without being bound by theory, surfactants contribute to the formation of a more stable dispersion of the aqueous phase in a continuous hydrocarbon phase (e.g., a multiphase mixture) within the halogenation reactor. Therefore, aqueous H₂O₂ solutions can be well dispersed within the continuous hydrocarbon phase (e.g., the adhesive). In addition, a more stable dispersion allows for an increase in the surface area between the aqueous and hydrocarbon phases, which in turn promotes the migration of HBr from the hydrocarbon phase to the aqueous phase for halogen regeneration via the oxidation of HBr with H2O2, resulting in increased halogenation of aliphatic elastomers using fewer halogen reactants.

[0023] definition

[0024] When describing elements of various embodiments of this disclosure, the articles "a," "an," and "described" are intended to indicate the presence of one or more elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that additional elements may exist in addition to those listed. Furthermore, it should be understood that references to "an embodiment" or "an embodiment" of this disclosure are not intended to exclude the existence of additional embodiments that also include the described features.

[0025] "Diluent" refers to a diluent or solvent. A diluent is specifically defined as a chemical that can act as a solvent (e.g., a solvent) for Lewis acids, other metal complexes, initiators, monomers, or other additives, but preferably not as a solvent for elastomers obtained through the polymerization of dissolved monomers. The diluent does not alter the composition of the polymerization medium, such as the components of the catalyst system, monomers, etc., or their general properties. However, it must be recognized that interactions can occur between the diluent and the reactants. In a preferred embodiment, the diluent does not react with the catalyst system components, monomers, etc., to any significant extent. Additionally, the term diluent includes a mixture of at least two or more diluents. In the practice of this disclosure, the diluent is typically a hydrocarbon liquid that can be chlorinated or fluorohalogenated, as disclosed in U.S. Patent No. 7,232,872.

[0026] "Solvent" refers to a hydrocarbon liquid that can act as a solvent for elastomeric polymers. In the practice of this disclosure, the solvent is typically a hydrocarbon liquid having the formula CxHy, where x is 5 to 20 and y is 12 to 22, such as hexane, isohexane, pentane, isopentane, and cyclohexene.

[0027] "Polymer (one or more)" refers to any homopolymer, copolymer, terpolymer, etc. Similarly, "copolymer (one or more)" refers to any polymer containing at least two monomers, optionally with other monomers. When a polymer is referred to as containing monomers, the monomers are present in the polymer in the polymer in the polymeric form of the monomers or in the polymeric form of monomer derivatives (e.g., monomer units). However, for ease of reference, the phrase includes the (corresponding) monomers, etc., as an abbreviation. Likewise, when a catalyst component is described as containing a neutral, stable form of the component, those skilled in the art will understand that the ionic form of the component is the form in which it reacts with the monomers to produce the polymer.

[0028] "Elastomer (one or more)" means any polymer or composition of polymers that conforms to the definition in ASTM D 1566: "a material capable of recovering from large deformation and which, or has been modified, to be substantially insoluble in (but swellable in) solvents if vulcanized." Elastomers are also commonly referred to as rubber. The term elastomer may be used interchangeably with the term "rubber" herein. Preferred elastomers have a melting point that cannot be measured by DSC, or if it can be measured by DSC, a melting point less than about 40°C, or preferably less than about 20°C, or less than about 0°C. Preferred elastomers have a glass transition temperature (Tg) measured by DSC of about -50°C or less.

[0029] "Mounney viscosity" or simply "viscosity" refers to the viscosity of rubber. It is defined as the shear torque required to resist the rotation of a cylindrical metal disk (or rotor) embedded in a cylindrical cavity within the rubber. The dimensions, test temperature, and procedures for determining Mooney viscosity of shear disk viscometers are defined in ASTM D1646. Mooney viscosity is measured in Mooney units.

[0030] For the purposes of this disclosure, the numbering scheme for the periodic table families is based on the IUPAC periodic table of elements.

[0031] The term "and / or" as used in phrases such as "A and / or B" in this document is intended to include "A and B", "A or B", "A" and "B".

[0032] The terms “substituent”, “radical”, “group”, and “moiety” are used interchangeably.

[0033] When used herein and unless otherwise specified, the term "Cn" refers to a hydrocarbon (one or more) containing n carbon atoms (one or more) per molecule, where n is a positive integer.

[0034] When used herein and unless otherwise specified, the term "hydrocarbon" means a class of compounds containing hydrogen atoms bonded to carbon and covers (i) saturated hydrocarbon compounds; (ii) unsaturated hydrocarbon compounds; and (iii) mixtures of hydrocarbon compounds (saturated and / or unsaturated), including mixtures of hydrocarbon compounds with different n values.

[0035] For the purposes of this disclosure and the appended claims, unless otherwise stated, the term "substituted" means that a hydrogen group has been replaced by a heteroatom or a heteroatom-containing group. For example, a "substituted hydrocarbon" is a hydrocarbon made of carbon and hydrogen, wherein at least one carbon (and one or more accompanying hydrogens) and / or at least one hydrogen is replaced by a heteroatom or a heteroatom-containing group.

[0036] As used herein, the term "isoolefin" refers to any olefin monomer having at least one carbon atom with two substitutions thereon. The term "polyolefin" as used herein refers to any monomer having two (e.g., "diene") or more double bonds (e.g., "triene," etc.). In some embodiments, a polyolefin is any monomer containing at least two conjugated double bonds, such as a conjugated diene (e.g., isoprene).

[0037] The phrase "isobutylene-based elastomer" or "isobutylene-based polymer" refers to an elastomer or polymer containing at least 70 mol% repeating units derived from isobutylene. Additionally, the term "butyl" is used interchangeably with the phrase "isobutylene-based" herein.

[0038] Elastomers and their components

[0039] Elastomers that can be used in the practice of this disclosure include a) polymers derived from at least one C4 to C7 isoolefin monomer and at least one polyolefin monomer and b) homopolymers of C4 to C7 isoolefin monomers. For copolymers, in one embodiment, the isoolefin-derived content in the copolymer is from about 70% by weight to about 99.5% by weight, for example from about 85% by weight to about 99.5% by weight of the total monomer-derived units. The total polyolefin-derived content in the copolymer is present in a mixture ranging from about 0.5% by weight to about 30% by weight, for example from about 0.5% by weight to about 15% by weight, for example from about 0.5% by weight to about 12% by weight, for example from about 0.5% by weight to about 8% by weight. For the purposes of this disclosure, a polyolefin refers to any monomer having two or more double bonds. In a preferred embodiment, a polyolefin is any monomer containing two conjugated double bonds and may be an aliphatic or aromatic monomer.

[0040] C4 to C7 isoolefins can be selected from compounds such as isobutylene, isobutene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-butene, 2-butene, methyl vinyl ether, indene, vinyltrimethylsilane, hexene, and 4-methyl-1-pentene. Polyolefins are C4 to C7 isoolefins. 14 Polyolefins, such as isoprene, butadiene, 2,3-dimethyl-1,3-butadiene, myrcene, 6,6-dimethyl-fullen, hexadiene, cyclopentadiene, alkylstyrene, and isoprene, as well as other monomers as disclosed in U.S. Patent No. 5,506,316.

[0041] The elastomer can also be a random copolymer having one or more C4 to C7 isoolefin-derived units and one or more alkylstyrene-derived units. In some embodiments, the random copolymer contains about 85% to about 93.9% by weight of isoolefin units, for example, about 86.9% to about 93.5% by weight. In some embodiments, the random copolymer contains about 5% to about 12% by weight of alkylstyrene units and about 1.1% to about 1.5% by weight of halogen. In one or more embodiments, the polymer can be a random elastomer copolymer containing about 8% to about 12% by weight of methylstyrene, a C4-C7 α-olefin, and methylstyrene. The poly(isobutylene-copolymer-p-methylstyrene) polymer is also known as an IMSM polymer.

[0042] Other elastomers suitable for use in this disclosure that contain C4 to C7 isoolefin-derived units include terpolymers comprising isoolefins and two polyolefins, wherein the polyolefins have different main chain structures prior to polymerization. Such terpolymers include C4 to C8 isoolefin-derived units, C4 to C7 isoolefin-derived units, and C4 to C7 isoolefin-derived units. 14Block and random terpolymers of polyolefin-derived units and alkylstyrene-derived units. One such terpolymer can be formed from isobutylene, isoprene, and alkylstyrene (preferably methylstyrene) monomers. Another suitable terpolymer can be polymerized from isobutylene, cyclopentadiene, and alkylstyrene monomers. Such terpolymers are obtained under cationic polymerization conditions.

[0043] Therefore, polymers that can be used herein can be described as copolymers of C4 isomonoolefin-derived units (e.g., isobutylene-derived units) and at least one other polymerizable unit. Non-limiting examples of isobutylene-based elastomers include poly(isobutylene), butyl rubber (isoprene-isobutylene) rubber ("IIR"), branched ("star-branched") butyl rubber, star-branched polyisobutylene rubber, block terpolymers of isoprene-isobutylene-styrene, random copolymers of isobutylene and p-methylstyrene, and random terpolymers of isobutylene, isoprene, and p-methylstyrene.

[0044] In some embodiments, the elastomer is an isobutylene-based elastomer obtained by reacting about 92 wt% to about 99.5 wt% of isobutylene with about 0.5 wt% to 8 wt% of isoprene, or an isobutylene-based elastomer obtained by reacting about 95 wt% to 99.5 wt% of isobutylene with about 0.5 wt% to about 5.0 wt% of isoprene. Such copolymers derived from isobutylene and isoprene are commonly referred to as butyl rubber.

[0045] High-purity isobutylene (typically about 95 wt% to about 100 wt%) and isoprene (e.g., about 95 wt% to about 99.9 wt%) can be used to manufacture butyl rubber. Impurities can affect isobutylene / isoprene conversion, polymer molecular weight distribution, and reactor performance. Monomer purity is controlled through purchase specifications and rigorous quality control, with additional purification performed at the production unit if necessary. High-purity isobutylene can be derived from fossil fuels, advanced circular processes, or bio-based sources.

[0046] The polymers described above can be prepared by any suitable polymerization. The polymers can be prepared using slurry polymerization or solution polymerization. If the polymer is produced in a slurry polymerization process, where the polymer precipitates from the reaction medium, the polymer is dissolved in a suitable solvent, for example, to produce a polymer adhesive, prior to halogenation. For polymers produced via solution polymerization, halogenation can be performed using the same polymer-containing solution or polymer adhesive after removing unreacted monomers and removing or neutralizing unused catalyst. The polymer adhesive may contain about 1% to about 70% by weight of the polymer, for example, about 10% to about 60% by weight, for example, about 10% to about 50% by weight, for example, about 10% to about 40% by weight, for example, about 20% to about 30% by weight.

[0047] In some embodiments, the elastomers of this disclosure may include a weight-average molecular weight (Mw) of about 380 kDa to about 2,000 kDa, such as about 390 kDa to about 1,000 kDa, such as about 400 kDa to about 850 kDa, such as about 425 kDa to about 750 kDa, such as about 450 kDa to about 650 kDa, as determined by gel permeation chromatography (GPC). In some embodiments, the elastomers of this disclosure may be characterized by a narrow molecular weight distribution (MWD) as determined by GPC, such as about 1.01 to about 5, such as about 2 to about 5, such as about 2.5 to about 4.5.

[0048] A high-purity diluent (typically about 98% to about 100% by weight) used as a catalyst diluent from a diluent recovery tower is combined with an initiator, and then with a catalyst. The initiator is typically HCl, and the catalyst is typically an alkylaluminum catalyst or an aluminum chloride catalyst. Figure 1 This is a schematic diagram 100 illustrating the formation of butyl rubber. When using an alkylaluminum catalyst, the catalyst diluent and catalyst are combined at 102 and mixed using a static mixer to ensure good distribution. When using an aluminum chloride catalyst, the catalyst diluent stream is split, and a portion of the catalyst diluent is cooled at 104 and fed through one or more aluminum chloride dissolution beds, subsequently recombine with another portion of the catalyst diluent to achieve the desired catalyst concentration. The catalyst / diluent / initiator stream is injected into reactor 106 (one or more) at a high speed to ensure good distribution in the reactor, for example, from about 1.5 m / s to about 5 m / s. The catalyst to initiator ratio can be from about 1 mol / mol to about 5 mol / mol, for example, from about 1.5 to about 2.5 mol / mol.

[0049] The reaction is sensitive to oxygenated compounds, oxygen, and moisture. Moisture is removed from fresh isoprene at 108 and from isobutylene at 110 before being fed to reactor 106. The diluent / monomer recycle stream is dried at 112 using a fixed-bed alumina and / or molecular sieve dryer to remove residual moisture and oxygenated compounds. The recycle solvent stream is dried at 114 using a fixed-bed molecular sieve dryer or by fractionation before being reused in the process. Both the recycle stream and the feed stream are equipped with moisture analyzers, oxygen analyzers, and oxygenate analyzers to ensure control of moisture, oxygen, and oxygenate levels. Light fractions, including oxygen, are removed from the distillate drum of the distillate recovery tower.

[0050] Feed blends and reactor

[0051] Isobutylene and isoprene in a diluent are prepared into a predetermined composition in a feed blend drum at point 116, cooled to -90°C to -100°C using a series of heat exchangers, and fed into reactor 106(one or more). A catalyst and a co-catalyst are prepared in a high-purity diluent and fed into reactor 106(one or more). A copolymer of isobutylene and isoprene is prepared in reactor 106(one or more). An exemplary diluent used is chloromethane. In some embodiments, depending on the grade, the feed blend contains about 20% to about 40% by weight of isobutylene and about 0.4% to about 1.4% by weight of isoprene, with the remainder being primarily diluent.

[0052] Butyl reactors scale over time and are periodically shut down for cleaning. Therefore, the butyl reaction process can be a semi-batch process with reactors in multiple production modes and multiple non-production modes. At the end of the production cycle, the production reactor is quenched by injecting alcohol or water into the reactor to stop the reaction, then flushed with a diluent at approximately -40°C to -80°C to remove most of the rubber slurry and gradually warmed. Solvent is introduced to further warm the reactor to 0°C to 50°C. Reactor 106 is then washed with solvent at 0°C to 90°C to remove the rubber scaling agent that has accumulated on the vessel surface. While cleaning reactor 106, the solvent is replaced with a diluent at -40°C to -80°C to gradually cool the reactor, then cooled to -90°C to -100°C to prepare for production. The flow rate, temperature, and duration of each non-production phase are managed to ensure that the mechanical design conditions of the reactor and reactor pumps are not compromised.

[0053] When the cooling reactor 106 is used for production, it is infused with a mixture of diluent, isobutylene, and isoprene. The concentrations of the diluent, isobutylene, and isoprene are set to simulate the normal background concentrations during reactor production to ensure the polymer quickly reaches specifications. The initiator and co-initiator are then injected at a high rate to ensure rapid initiation of the reaction, and then set to a normal rate to ensure the rubber meets specifications.

[0054] Solvent replacement method

[0055] At 118, an alcohol or water quencher is injected into the reactor overflow outlet to quench the catalyst, for example as described in US4,154,924, which is incorporated herein by reference. Figure 2 This is a schematic diagram illustrating the solvent displacement process 118. (As shown...) Figure 2As shown, before adding quench 202 to the reactor outlet, quench 202 can be premixed with a polar diluent and then diluted with a solvent, with or without a static mixer. Quench 202 is injected and mixed with the reactor slurry at 204, with or without a mechanical mixer. The resulting stream is then fed to solution drum 206, where solvent vapor 208 is added to heat and dissolve the polymer to prepare a polymer / solvent solution called an adhesive. A typical solvent can be a mixture of n-hexane and hexane isomers. The liquid outlet 210 of the solution drum is then directed to a surge drum 212. Solution drum 206 and surge drum 212 can be combined into a single drum. The solution can be periodically sampled and analyzed to monitor polymer properties. Statistical process control techniques and basic or empirical models can be used to monitor product quality and guide the optimization of polymerization conditions. The drum(s) operating temperature can be from about -20°C to about +30°C, for example, from about -20°C to about +10°C, and the operating pressure can be from about 0 kPag to about 1000 kPag, for example, from about 0 kPag to about 500 kPag. The method is operated to produce a vapor stream comprising about 0% to about 30% of the total drum feed, for example, as described in U.S. Patent No. 3,257,349, which is incorporated herein by reference. A liquid stream containing adhesive / solvent / diluent / unreacted monomers from these drums is conveyed via line 216 to adhesive stripping tower 214. A vapor stream containing solvent / diluent / unreacted monomers from drums 206 and 212 is conveyed via line 216 to adhesive stripping tower 214 or via line 218 to the top of the adhesive stripping tower. Solvent vapors are injected at the bottom of the tower via line 220 and flow countercurrently to the adhesive. The overhead distillate from the adhesive stripping column, containing diluent, unreacted monomers, and a portion of the solvent, is conveyed via line 222 to solvent recovery column 224. High-purity solvent is recovered in the bottom stream (line 226) for recycling, and diluent and unreacted monomers are recovered in the overhead distillate (line 228) and sent to diluent recycle dryer 230. The diluent / monomer recycle stream (line 240) from the solvent displacement process section is dried using a combination of a fixed-bed alumina and chloride-resistant molecular sieve dryer 242 to remove moisture. The diluent / monomer stream 244 is then sent to a recycling column to separate and recover the diluent and monomers for reuse in the process.

[0056] The adhesive stripping tower 214 is operated to ensure very low monomer concentrations in the adhesive stream, as any monomer could react during subsequent halogenation and exceed desired product specifications (e.g., industrial hygiene controls). For good industrial hygiene controls, the monomer concentration in the adhesive stream (line 232) is <200 wtppm, and typically <50 wtppm.

[0057] The adhesive feed stream (line 232) from the bottom of the adhesive stripping column 214 is flashed into one or two adhesive concentrator drums 234. The adhesive is cooled and its concentration is increased. The vapor stream (line 234) at the top of the adhesive concentrator column has a temperature determined by the utility temperature (typically cooling water or air). The operating pressure of the concentrator drums 234 (one or more) is determined by the solvent vapor pressure profile, typically a mixture of n-hexane and hexane isomers. The adhesive concentrators 234 (one or more) operate at pressures of about 40 kPaa to about 150 kPaa, for example about 50 kPaa to about 100 kPaa, as described, for example, in U.S. Patent No. 3,257,349, which is incorporated herein by reference. The adhesive concentrator drum 234 is equipped with side trays or baffles (spray plates) that allow solvent vapors to separate from the viscous adhesive and minimize vapor entrainment in the bottom adhesive stream (line 236). The overhead solvent from the adhesive concentrator is circulated in the process. The bottom adhesive stream (line 236) is sent to a storage tank 238. The adhesive concentration sent to storage tank 238 is approximately 18% to approximately 30% by weight, for example, approximately 22% to approximately 28% by weight. Thermal integration is widely used in the solvent recovery section of the equipment and the resizing section of the unit to improve energy efficiency.

[0058] Bromination and Regeneration Methods

[0059] The preparation of butyl elastomers via conventional bromination is described in detail in, for example, U.S. Patent Nos. 2,356,128, 4,474,924, 4,068,051, 7,232,872, and 7,414,101, each of which is incorporated herein by reference. As disclosed in these references, monomers and catalysts are dissolved in a hydrocarbon diluent, and polymerization occurs in the hydrocarbon diluent. If the polymerization is slurry polymerization, the diluent is selected to ensure that the resulting polymer precipitates out of the diluent after formation. Slurry polymerization typically produces a slurry containing 10 to 70% by weight solids. After polymerization, for solution polymerization (where the polymer remains dissolved in the solvent) and slurry polymerization, the polymer must be recovered from the solvent. This is typically carried out in a flash drum, followed by washing and drying of the polymer to produce rubber pellets suitable for packaging and packaging.

[0060] Halogenation of dissolved polymers is carried out by adding bromine to the polymer adhesive solution. Halogenation of isobutylene copolymers is also described in U.S. Patent No. 5,670,582, which is incorporated herein by reference. In one embodiment, the halogen weight percentage in the formed elastomer is 0.1 to 10% by weight, based on the weight of the halogenated elastomer; in another embodiment, it is 0.5 to 5% by weight. In yet another embodiment, the halogen weight percentage in the halogenated rubber is 1.0 to 2.5% by weight.

[0061] Following halogenation, the solution undergoes a neutralization step, in which HBr reacts with an aqueous caustic alkali solution to produce a soluble salt in the aqueous phase. After neutralization, some or all of the aqueous phase may be removed before removing the hydrocarbon solvent still dissolved in the halogenated elastomer. For this dehydration, the solution temperature should not exceed 100°C, otherwise the properties of the final halogenated polymer may be negatively affected. After the neutralization step, a free radical scavenger may be added to the brominated butyl elastomer according to this disclosure.

[0062] The isobutylene-based polymer is then refined by stripping the solvent from the slurry or solution and drying the resulting solid polymer into granular form that can be packaged or packaged. Drying is typically accomplished using a continuous screw-path extruder, in which the elastomeric solids are molded as the polymer passes through the extruder, and water is extruded from the mixture or evaporated through the extruder's helical blades.

[0063] Isobutylene-based polymers with unsaturated moieties in their polymer backbone, such as isobutylene-isoprene polymers, can be readily halogenated via an ionic mechanism during contact with a halogen source (e.g., molecular bromine or chlorine) and at temperatures ranging from about 20°C to about 80°C. Isobutylene-based polymers without unsaturated moieties in their polymer backbone, such as isobutylene-alkylstyrene polymers, can undergo halogenation under radical halogenation conditions, such as in the presence of white photochemical light, or by including an organic radical initiator in the reaction mixture at temperatures ranging from about 20°C to about 90°C.

[0064] Regenerative halogenation can be carried out by contacting a polymer solution with a halogenating agent and an emulsion containing an oxidizing agent. The oxidizing agent can interact with the hydrogen halides generated during halogenation, converting the halogen back to a form that can be used for further halogenation of the polymer, thereby improving halogen utilization (e.g., converting HBr back to Br2).

[0065] Halogenation and neutralization can be performed using any suitable method. Figure 3 This is a schematic diagram 300 illustrating the halogenation and neutralization of an adhesive to form a halogenated butyl rubber. In some embodiments, the methods disclosed herein are continuous processes. For example... Figure 3 As shown, a solution containing oxidant 302 and a solution containing surfactant 304 are pumped to mixing system 305 via pumps 303A and 303B, respectively, to form an aqueous phase. Mixing system 305 may include one or more static or mechanical mixing devices, such as a static mixing device. Solvent 306 is added online to the aqueous phase and mixed in mixing system 307 to form an emulsion. Mixing system 307 may include one or more static or mechanical mixing devices, such as a static mixing device.

[0066] The oxidant that can be used in the methods of this disclosure is an oxygen-containing material, such as a water-soluble oxygen-containing agent. Suitable reagents include peroxides and peroxide-forming substances. In some embodiments, the oxidant is selected from hydrogen peroxide, organic hydrogen peroxide, sodium chlorate, sodium bromate, sodium hypochlorite or sodium bromate, oxygen, nitrogen oxides, ozone, urea peroxide, acids such as pertitanic acid, perzirconic acid, perchromic acid, permolybdic acid, pertungstic acid, peruranic acid, perboric acid, perphosphoric acid, perpyrophosphate, persulfate, perchloric acid, perchlorate, periodic acid, or combinations thereof. Among the above, hydrogen peroxide and compounds that form hydrogen peroxide, such as peracids and sodium peroxide, have been found to be very suitable for halogen regeneration. In at least one embodiment, the oxidant is hydrogen peroxide.

[0067] In some embodiments, the solution 302 containing the oxidant is a mixture of water and the oxidant, wherein the oxidant accounts for about 10% to about 60% by weight, for example about 20% to about 50% by weight, for example about 30% to about 40% by weight of the solution 302.

[0068] In some embodiments, solution 304 is a surfactant, a mixture of surfactants, or an aqueous solution thereof. When surfactant 304 or a solution thereof is combined with oxidant solution 302 to form an aqueous phase, surfactant 304 comprises about 0.1% to about 5% by weight, for example about 0.2% to about 4% by weight, for example about 0.3% to about 3% by weight, for example about 0.5% to about 2% by weight of the aqueous phase. In some embodiments, the surfactant is a nonionic surfactant, such as an ethoxylated alcohol emulsifier, such as octylphenol ethoxylate, ethoxytridecyl alcohol, polysorbate 80, poloxamer, and combinations thereof. In at least one embodiment, the surfactant may include any one or more nonionic surfactants known to those skilled in the art.

[0069] In at least one embodiment, the volume and flow rate of solutions 302 and 304 can be controlled via pumps 303A and 303B. The volume ratio of the two components can be expressed as the weight ratio of surfactant to oxidant (lbs surfactant / 100 lbs oxidant). In some embodiments, the aqueous phase contains about 1 lbs surfactant / 100 lbs oxidant to about 3.8 lbs surfactant / 100 lbs oxidant, for example, about 1.5 lbs surfactant / 100 lbs oxidant to about 3.5 lbs surfactant / 100 lbs oxidant, for example, about 2 lbs surfactant / 100 lbs oxidant to about 3 lbs surfactant / 100 lbs oxidant. In some embodiments, the oxidant is H2O2.

[0070] In at least one embodiment, solvent 306 can be any solvent suitable for or used to form the polymeric adhesive. In one embodiment, the solvent is selected to be the same solvent used to form the polymeric adhesive. Suitable solvents include hydrocarbons, such as pentane, hexane, heptane, etc., inert halogenated hydrocarbons, such as mono-, di-, or tri-halogenated C1-C6 alkanes or halogenated aromatic and / or aliphatic hydrocarbons, such as dichloroethane, n-butyl chloride, and monochlorobenzene or mixtures of hydrocarbons, and one or more inert halogenated hydrocarbon solvents, such as chloromethane, dichloromethane, chloroethane, and / or bromoethane. Furthermore, the solvent can be a combination of solvents provided herein, including their isomers.

[0071] In some embodiments, the emulsion formed by combining solvent 306 and the aqueous phase comprises a solvent to aqueous phase volume ratio of about 40:1 to about 1:1, for example about 20:1 to about 1.5:1, for example about 10:1 to about 2:1.

[0072] The memory 308 (which corresponds to) will come from memory 308 (which corresponds to Figure 2 The adhesive in the adhesive storage device 238 is pumped through a series of filters, such as ceramic filters with pore sizes of about 400 μm to about 600 μm, and added online with the emulsion in a well-mixed halogenation reactor 314. A halogen source, such as Br2, Cl2, NaBr, NaCl, or combinations thereof, is added via line 312 to form a halogenated butyl rubber. In at least one embodiment, the series of filters is configured to prevent solid particles (e.g., rust particles) from entering the halogenation system. The halogen can be vapor chlorine or liquid bromine, depending on the grade of the halogenated butyl rubber being prepared, for example, liquid bromine. The halogenation reactor 314 can be a CSTR (continuous stirred tank reactor) or a high-speed mixing device, such as one from STRATCO. TM CONTACTOR TM In some implementations, the reactor vessel is a stirred tank, a conventional stirred tank, a packed tower, or a tube with sufficient flow and residence time to allow the desired reaction to occur.

[0073] In some embodiments, the adhesive supplied to the halogenation reactor 314 is controlled such that the concentration of rubber present therein is from about 20% to about 35% by weight, for example from about 22% to about 30% by weight, for example from about 24% to about 30% by weight.

[0074] In some embodiments, the peroxide to bromine ratio (mol:mol) is about 0.2:1 to about 0.8:1, for example about 0.4:1 to about 0.7:1, for example about 0.4:1 to about 0.6:1. In one or more additional or alternative embodiments, the bromine to rubber ratio is about 18 kg / ton to about 45 kg / ton, for example about 25 kg / ton to about 45 kg / ton, for example about 25 kg / ton to about 35 kg / ton, for example about 25 kg / ton to about 30 kg / ton.

[0075] The residence time for the halogenation reaction is from about 0.5 minutes to about 60 minutes, for example, from about 0.5 minutes to about 25 minutes, for example, from about 1 minute to about 10 minutes, for example, from about 1 minute to about 5 minutes, for example, from about 2 minutes to about 3 minutes. In some embodiments, the halogenation reaction temperature is from about 20°C to about 70°C, for example, from about 30°C to about 65°C, for example, from about 40°C to about 60°C.

[0076] In some embodiments, the bromine utilization rate of the halogenation reaction is about 60% to about 90%, for example about 65% to about 85%, for example about 70% to about 80%. In some embodiments, the H2O2 conversion rate of the halogenation reaction is about 60% to about 99.9%, for example about 65% to about 99%, for example about 70% to about 95%.

[0077] Because a significant portion of the hydrogen halides (e.g., hydrogen bromide) generated in situ as a byproduct of the halogenation process are oxidized to regenerate useful halogens, a smaller amount of halogenating agent is initially required to achieve a given degree of polymer halogenation than would be the case if no oxidant is used in the reaction. As a general rule, the amount of halogenating agent present in the reaction medium can vary from about 0.1 php to about 10 php (parts by weight / 100 parts by weight of polymer), for example, from about 0.2 php to about 6 php, for example, from about 0.2 php to about 5 php.

[0078] In some embodiments, a halogen source may be added directly to the halogenation reactor 314 from an external source via line 312B. In one or more embodiments, the halogen source added to the halogenation reactor 314 via line 312B is HBr and / or any form thereof. The HBr halogen source may be introduced into the halogenation reactor 314 via line 312B as HBr gas or an aqueous HBr solution. In at least one embodiment, the halogen source is an aqueous HBr solution having about 20 vol% to about 90 vol% HBr, for example, about 30 vol% to about 70 vol%, for example, about 40 vol% to about 50 vol%.

[0079] After the halogenation reaction is completed, the polymer is recovered using one or more techniques known to those skilled in the art (line 324), such as neutralization with a dilute caustic alkali, washing with water and removing the solvent, for example by steam stripping or precipitation with a lower alcohol such as isopropanol. For example, the method detailed in U.S. Patent No. 5,670,582 is incorporated herein by reference.

[0080] In one or more embodiments, the polymer and reaction byproducts (line 324) are mixed with a neutralizing agent (such as sodium hydroxide) to neutralize the resulting HCl or HBr / bromine. Once neutralized, a stabilizing additive may be added to form a stable emulsion. In some embodiments, the additive is a calcium stearate dispersion containing a surfactant. In some embodiments, the surfactant is a nonionic alcohol ethoxylate, such as ethoxytridecyl alcohol. The final neutralization stage may include one or more separate process units, such as about one to about four separate process units, individually selected from, but not limited to, CSTR, CONTACTOR. TM Static mixers or combinations thereof.

[0081] In some embodiments, the stabilizing additive is calcium stearate, calcium palmitate, zinc stearate, or zinc palmitate. In some embodiments, the stabilizing additive is an alcohol, such as Impentin T / 070 (manufactured by KLK Oleo), Synperonic 13 / 7-85 (manufactured by Croda, formerly known as Volpo X078), Tergitol 15-S-7 (manufactured by Dow), or Genapol X050 (manufactured by Clariant). In some embodiments, the stabilizing additive is a low critical solution temperature (LCST) material, such as those described in U.S. Patent No. 10,611,886 (incorporated herein by reference), such as poly(N-isopropylacrylamide), poly(N-isopropylacrylamide-copolymer-N,N-dimethylacrylamide, poly(N-isopropylacrylamide)-alternating-2-hydroxyethyl methacrylate, poly(N-vinylcaprolactam), poly(N,N-diethylacrylamide), poly[2-(dimethylamino)ethyl methacrylate], poly(2- (Azoline) glyelastomer, poly(3-ethyl-N-vinyl-2-pyrrolidone), hydroxybutyl chitosan, polyoxyethylene (20) sorbitol monostearate, polyoxyethylene (20) sorbitol monolaurate, polyoxyethylene (20) sorbitol monooleate, methylcellulose, hydroxypropylcellulose, hydroxyethyl methylcellulose, hydroxypropyl methylcellulose, poly(ethylene glycol) methacrylate having 2 to 6 ethylene glycol units, or polyethylene glycol-copolymer-polypropylene glycol, such as those having 2 to 6 ethylene glycol units and 2 to 6 polypropylene units.

[0082] Figure 4 The diagram illustrates the feeding of an aqueous / hydrocarbon emulsion from the halogenation and neutralization section (line 324) to a flash drum 402 for solvent removal and recovery (line 406). The aqueous / hydrocarbon emulsion is flashed into the stirred flash drum 402, where steam is injected into the liquid to strip the solvent from the stream. Rubber fragments are formed in the flash drum 402, and an additive (line 408) is added to the flash drum 402 to prevent polymer agglomeration and container clogging. The additive is typically a calcium stearate dispersion with a surfactant. The aqueous / fragment mixture flows to a stirred stripper 404, where the additional residence time and reduced pressure allow the solvent to diffuse from the fragments into the vapor stream (line 410). Additional steam can be injected into the stripper 404 to aid the solvent diffusion process. Water is sprayed into the vapor spaces of the flash drum 402 and the stripper 404 to reduce container fouling and provide cooling; the spray pattern is typically a hollow cone or a solid cone. The slurry concentration of the flash drum 402 and stripper 404 process units is controlled, for example, by controlling the flow rates of calcium and surfactant injected into the flash drum, to minimize the tendency for agglomeration and clogging, thereby keeping the particle size within the desired operating parameters. Lower injection rates provide higher particle sizes, and vice versa.

[0083] The solvent / water in the vapor stream (line 406) from the flash drum is condensed, and the solvent is separated in the condenser / separator 412 and sent to the storage for subsequent drying and recycling, while the water is recycled in the process.

[0084] Flash drum 402 operates at a pressure of approximately 140 kPa to approximately 190 kPa, and the liquid temperature is approximately 105°C to approximately 120°C. Stripper 404 operates at a pressure of approximately 80 kPa to approximately 130 kPa, for example, approximately 90 kPa to approximately 120 kPa, and the liquid temperature is approximately 90°C to approximately 110°C. The pressure of stripper 404 is controlled by a vacuum pump or vacuum ejector. The stripper overhead feed stream (line 410) is circulated back to flash drum 402 (one or more) to save energy. In larger production facilities, multiple flash drums (one or more) and stripper towers (one or more) can be operated in parallel. In facilities employing parallel flash drums (one or more) and stripper towers (one or more), instrumentation can be used to ensure a uniform flow distribution among the parallel units.

[0085] Flash drum 402 may have an agitator to ensure good mixing between the adhesive and water and to promote particle formation, such as an eccentric flat blade agitator. Stripping tower 404 agitators for ensuring good mixing of floating rubber particles in the liquid include inclined blade turbines that pump upwards or downwards, and water jets that pump upwards or downwards.

[0086] Particle size should be controlled in flash drum 402 and stripping tower 404, as particles that are too small cause scaling and difficulty in dehydration / drying of the container and piping systems, while particles that are too large make solvent removal difficult and may cause blockage of the piping system. Particle size is controlled by adding calcium stearate, the particle size and particle size distribution of calcium stearate, and the surfactant added together with calcium stearate. Particle size distribution is measured and monitored, for example, depending on downstream processing, such as extruder size.

[0087] Structure III stabilizers

[0088] Brominated butyl rubber can be described as having different types of monomer units, referred to as Structure 1, Structure 2, and Structure 3, etc. Structure 1 refers to the unbrominated isoprene unit. Structure 2 refers to the isoprene unit brominated at a carbon atom along the polymer backbone. Structure 3 refers to the isoprene unit brominated at a methyl substituent. During the bromination of butyl rubber, brominated butyl rubber can have a large amount of Structure 2 units formed; however, over time, the formed brominated butyl rubber begins to have an undesirable high content of Structure 3, at which point the bromination conditions must be analyzed and modified, and / or bromination must be stopped. Ultimately, brominated butyl rubber with a high Structure 3 content reduces the yield of brominated butyl rubber with a high Structure 2 content. A high Structure 3 content also leads to an increase in the Mooney viscosity of brominated butyl rubber.

[0089] In one or more embodiments, the structure III stabilizer may be added at one or more locations during the halogenation process, such as upstream of the halogenation reactor. A free radical stabilizer, free radical scavenger, or antioxidant is provided at the upstream location of the halogenation reactor; these are collectively referred to herein as "structure III stabilizers." The structure III stabilizer may be an organically soluble or water-compatible compound, such as an oil-soluble compound or a hexane-soluble compound.

[0090] Suitable structure III stabilizers include sterically hindered nitryl ethers, sterically hindered nitryl radicals, butylated hydroxytoluene (BHT), hydrogenated hydroxycinnamate, thiodipropionate, phosphites, and combinations thereof. Commercially available examples of structure III stabilizers that can be added during the preparation of the halogenated butyl rubber of this disclosure include, but are not limited to, TEMPO, Tinuvin™ NOR 371, Irganox PS 800, Irganox 1035, Irganox 1010, Irganox 1076, and Irgafos 168. TEMPO is a term commonly used to refer to (2,2,6,6-tetramethylpiperidin-1-yl)oxy. The sterically hindered nitryl radical can be TEMPO. Tinuvin™ NOR 371, a high molecular weight hindered amine NOR stabilizer, can be used and is commercially available from BASF as a plastic additive. Irganox PS 800, commercially available from CIBA, is the trade name for bis(dodecyl-3,3'-thiodipropionate). Irganox 1035, commercially available from CIBA / BASF, is the trade name for thiodiethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate). Irganox 1010, commercially available from BASF, is the trade name for pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate). Irganox 1076, commercially available from CIBA, is the trade name for octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Stericly hindered phenols may include BHT, Irganox PS 800, Irganox 1035, or combinations thereof. Irgafos 168, which is commercially available from BASF and is a general-purpose phosphite, can be used. In some embodiments, other structure III stabilizers may be added to the brominated butyl rubber of this disclosure, including but not limited to light stabilizers and UV absorbers.

[0091] In one implementation, the structure III stabilizer may be added at more than one location during the halogenation process.

[0092] In some embodiments, the total amount of Structure III stabilizer to be added during the preparation of halogenated butyl rubber is greater than about 20 ppm, for example greater than 50 ppm, for example greater than 75 ppm, for example greater than 100 ppm, to less than about 500 ppm, for example less than about 400 ppm, for example less than about 300 ppm, for example less than about 200 ppm, for example less than about 150 ppm, for example less than about 100 ppm. The ppm weight basis is relative to the weight of the halogenated butyl rubber (whether in solution, slurry, or recycled).

[0093] Refined

[0094] The bottom feed stream containing rubber fragments and water from stripping tower (one or more) at point 414 is conveyed (via line 420) to the stirred slurry tank 502, such as... Figure 5 As shown. Figure 5 This is a schematic diagram illustrating particle finishing. Typically, inclined blade impellers or a combination of inclined and flat blade impellers are used in upward or downward pumping modes.

[0095] Rubber pellets / water slurry are pumped to dewatering screens 504 (one or more) to remove total water. The rubber pellets are then fed into one or more extruders in series, such as a dewatering extruder 506 and a drying extruder 508, to process the rubber pellets. The dewatering extruder and the first-stage drying extruders 506, 508 can be one or more of the following: expander, press, dewatering extruder, slurry dewatering unit, volatiles control unit, etc. The final-stage drying extruder can be a twin-screw drying extruder, for example, as described in U.S. Patent No. 7,858,735, which is incorporated herein by reference. Temperature and pressure in the extruder are controlled by adjusting the limits at the extruder outlet, typically using a fixed or variable die. Heat can be added by using a steam-jacketed extruder. Inert gases can be injected to improve drying, as described in U.S. Patent No. 4,508,592, which is incorporated herein by reference. Polymer additives are injected at various stages of the extrusion process to meet product specifications, and depending on the grade, may include zero or one of the following polymer additives: epoxidized soybean oil, calcium stearate, butylated hydroxytoluene, Irganox, or antioxidants.

[0096] The pellets from the final drying extruder are then conveyed (line 510) to a fluidized bed conveyor 512 for drying to product specifications. The rubber pellets can be transported via a mechanical conveyor. In some embodiments, the fluidized bed conveyor 512 has two sections, consisting of a primary hot section for drying the pellets and a secondary cooling section for cooling the pellets. The pellets from the fluidized bed conveyor 512 are then conveyed to a packaging unit 514, where the pellets are compacted into bales, packaged, and their quality checked. The final rubber polymer product at 516 is stored in a warehouse for distribution to customers. Large production facilities operate multiple parallel extrusion and fluidized bed drying lines. Solvent vapors from the slurry tank, extruder, and fluidized bed conveyor can be captured in an air collection system for treatment.

[0097] Rubber particles are removed from the finishing water recovered from the dewatering screens and extruders for recycling or disposal. The finishing water, after particle removal, is recycled to the resizing and halogenation units, and excess water is removed from the process. The excess water will be further treated at the facility prior to final disposal. Additional antifouling agents and additives may be added to the circulating water to reduce scaling and control pH. Additives may include, but are not limited to, zero or one of the following: calcium chloride, patented antifouling agents such as PETROFLO. TM Or borate-based buffers.

[0098] For some implementations involving halogen regeneration, additives, including epoxidized soybean oil (also known as ESBO) and calcium stearate, can be added during the regeneration process. For example, ESBO can be added in the drying extruder 508 at a range of about 1 to about 2 phr before or during drying. Alternatively, calcium stearate can be added to the adhesive during neutralization, and / or calcium stearate can be added to the flash drum to help prevent the polymer from adhering to the equipment and to control the rubber particle size in the water slurry.

[0099] In some implementations, additives, such as ESBO, may be added to stripper 404 and / or line 414.

[0100] Physical properties of halogenated butyl elastomers

[0101] The physical and mechanical properties of the halogenated butyl elastomers described herein can be incorporated into typical liner formulations to determine the physical and mechanical properties of these materials. In some embodiments, the halogenated butyl elastomers produced by the methods detailed herein (after compounding) have an initial modulus (determined by ASTM D412) of about 9.5 MPa to about 10.3 MPa, for example about 9.6 MPa to about 10.2 MPa, for example about 9.7 MPa to about 10 MPa. In one or more embodiments, the halogenated butyl elastomers of this disclosure (after compounding) exhibit an initial elongation at break (determined by ASTM D412) of about 775% to about 825%, for example about 785% to about 815%, for example about 800% to about 810%. In one or more embodiments, the halogenated butyl elastomer of this disclosure (after compounding) exhibits an initial tear strength (as determined by ASTM D624) of about 34.1 N / mm to about 37.5 N / mm, for example about 35 N / mm to about 37 N / mm, for example about 35 N / mm to about 36 N / mm. In one or more embodiments, the halogenated butyl elastomer of this disclosure (after compounding) exhibits an initial hardness value of about 45 to about 46 (as determined by ASTM D2240).

[0102] The halogenated butyl elastomers disclosed herein can undergo intentional aging processes to provide information related to the long-term thermal and mechanical stability of the material. Without being bound by theory, it is believed that the aged Mooney viscosity typically exhibits a time-temperature dependence, such that aging for a longer period at a lower temperature is roughly equivalent to aging for a shorter period at a higher temperature. For example, in some embodiments, it is believed that the aged Mooney viscosity measured after approximately 7 days of exposure to approximately 80°C is roughly equivalent to the aged Mooney viscosity measured after approximately 21 months of exposure to approximately 33°C. Furthermore, this thermally induced viscoelastic change will correspond to changes in physical and mechanical properties.

[0103] In some embodiments, the aged halogenated butyl elastomer produced by the methods detailed herein has an aging modulus (measured by ASTM D412) of about 7.9 MPa to about 8.65 MPa, for example, about 8.45 MPa to about 8.6 MPa, or for example, about 8.45 MPa to about 8.55 MPa, after aging for 7 days at about 80°C. In one or more embodiments, the aged halogenated butyl elastomer of this disclosure exhibits an aging elongation at break of about 500% to about 650%, for example, about 550% to about 625%, or for example, about 575% to about 620%, after aging for 7 days at about 80°C. In one or more embodiments, the aged halogenated butyl elastomer of this disclosure exhibits an aging tear strength of about 33.5 N / mm to about 36 N / mm, for example, about 34 N / mm to about 36 N / mm, or for example, about 35 N / mm to about 36 N / mm, after aging for 7 days at about 80°C. In one or more embodiments, when aged at about 80°C for 7 days, the aged halogenated butyl elastomer of this disclosure exhibits an aging hardness value of about 55 to about 58 (measured by ASTM D2240).

[0104] In some embodiments, the halogenated butyl elastomers produced by the methods detailed above exhibit an initial Mooney viscosity (measured at 100°C by ASTM D1646) of about 30 Mooney units (MU) to about 35 MU, for example, about 31 MU to about 33 MU, or about 31 MU to about 32 MU. Furthermore, when aged at about 80°C for 7 days, the halogenated butyl elastomers of this disclosure exhibit a Mooney viscosity of about 32.5 MU to about 35.5 MU, for example, about 33 MU to about 35 MU, or about 34.5 MU to about 33.5 MU. In some embodiments, when aged at about 80°C for 7 days, the halogenated butyl elastomers of this disclosure exhibit a Mooney viscosity change of about 2.5 MU to about 5 MU, for example, about 2.5 MU to about 3.5 MU, or about 2.5 MU to about 3.2 MU, or about 2.5 MU to about 2.7 MU.

[0105] Industrial applicability

[0106] The brominated elastomer compositions disclosed herein can be used to prepare any number of articles. In some embodiments, the articles are selected from tire-cured airbags, tire liners, tire inner tubes, and air sleeves. In some embodiments, the articles are hoses or multilayer hoses, such as hose assemblies containing polyamide as one of the constituent layers. Other useful articles that can be prepared additionally or alternatively using the polymers disclosed herein include air spring airbags, seals, molding articles, cable housings, rubber-based drug plugs, and other articles disclosed in THE VANDERBILT RUBBER HANDBOOK, pp. 637-772 (edited by Ohm, RTVanderbilt Company, Inc., 1990).

[0107] Environmental and safety considerations

[0108] The methods described herein offer several benefits that are not typically achieved by current commercial methods. In fact, the methods disclosed herein provide additional safety, environmental, and raw material preservation impacts not provided by prior methods and applications. For example, the methods disclosed herein can result in a 30% reduction in bromine delivery (liquid and / or gas phases), thereby increasing personal and environmental safety by reducing the handling of hazardous materials. Additionally or alternatively, the methods disclosed herein can reduce the use and reuse of bromine / bromine and reduce the total amount of dissolved solids (e.g., bromide salts) present in industrial wastewater streams, as determined by gravimetric analysis. In some embodiments, the methods disclosed herein reduce the total amount of dissolved solids (e.g., bromide salts) present in industrial wastewater streams by about 45% to about 65%, for example, about 50% to about 60%, compared to conventional methods. In one or more embodiments, the industrial wastewater stream derived from the methods disclosed herein includes about 2,000 mg / L to about 2,650 mg / L of dissolved solids (e.g., bromide salts), for example, 2,015 mg / L to about 2,645 mg / L. Not wishing to be bound by theory, this reduction in waste solids present in industrial wastewater streams is achieved by decreasing the input bromine requirement for such halogenation reactions (as exemplified by the corresponding hydrogen peroxide to Br2 ratio and / or Br2 to rubber ratio). As a result, the method disclosed herein can be attributed to increased personal and environmental safety as well as increased raw material conservation.

[0109] Example

[0110] Mooney viscosity

[0111] Mooney viscosity of elastomers and blends was tested using an MV-2000 instrument (Alpha Technologies) according to ASTM standard D1646 via a large rotor. Elastomers were tested at 125°C with a 1-minute pause before the rotor began rotating, and the test duration was 8 minutes. The Mooney viscosity of the elastomer was calculated at 8 minutes and reported as ML1+8@125°C. For blends, the test was performed at 100°C with a 1-minute pause before the rotor began rotating, and the test duration was 4 minutes; the Mooney viscosity result was reported as ML1+4@100°C. These methods were established using Enterprise software (Alpha Technologies) to report these values ​​at the end of the test.

[0112] Nuclear magnetic resonance spectroscopy (NMR)

[0113] Acquired at 25°C on a DD2 500MHz spectrometer (Agilent) with a 5mm H / F probe. 1 ¹H NMR spectra. Spectroscopy was performed using a standard 5mm tube at room temperature with 30 nm... o The apex angle, 5 s delay, and 128 transients were measured. The polymer sample was dissolved in 1,1,2,2-tetrachloroethane-d2 at a concentration of 30 mg / mL.

[0114] Fourier transform infrared spectroscopy (FTIR)

[0115] The quantification of bromide functional structures (Str I, II, and III) in elastomers and other components or additives present was determined using a PerkinElmer Frontier FTIR spectrometer equipped with a triglycine sulfate (TGS) detector and sample shuttle. The spectrometer was controlled by PerkinElmer Spectrum™ 10.6.0 software. Infrared spectra of the elastomers were obtained using an automated hydraulic press (Carver) with 0.06 cm thick compression-molded film samples. [The remaining text appears to be incomplete and requires further context.] -1 FTIR spectra were collected using 16 scans at a high resolution, with a scan range of 6525–400 cm⁻¹. -1 All FTIR spectra are for the common region 4400-4250 cm⁻¹. -1 Normalized, and in the range of 4980-2040cm -1 The base absorbance was measured.

[0116] X-ray fluorescence spectroscopy (XRF)

[0117] Elemental analysis was performed using a panalytical axios with a chromium X-ray tube. For X-ray fluorescence spectroscopy (XRF), the apparatus was able to analyze Br, Ca, and low levels of Fe using calibration standards prepared with the same polymer matrix. XRF tests were performed on a molded elastomer disk with a smooth surface, molded for 5 minutes at 120°C and 11000 kPa (1600 psi) using a metal ring (0.5 inches thick [2.54 cm] and 2 inches in diameter [5.08 cm]), followed by molding for 5 minutes at 11000 kPa (1600 psi) in a cooled press. Three samples were tested, and the average value was reported.

[0118] Material preparation and processing

[0119] Halogenated butyl rubber samples were prepared using conventional regenerative bromination methods (e.g., the method disclosed in U.S. Patent No. 5,670,582). Tables 1 and 2 summarize the various processing parameters and data used herein. For test batches to be compared with control batches, the molar ratio of peroxide to bromine was maintained at approximately 0.4 to approximately 0.6 (mol:mol). The ratio of bromine to rubber was adjusted to maintain the target range for total weight % bromine and / or functionalized bromine covalently bonded to the polymer backbone. Thus, bromine utilization was in the range of approximately 60% to approximately 80%, and could be further increased with a larger molar ratio of peroxide to bromine and a longer residence time. Undesirable brominated and acidic substances were monitored and minimized by adding sufficient 10% caustic soda solution to maintain a pH of approximately 9 to approximately 10 and a minimum molar ratio of caustic soda to unreacted bromine of approximately 2.2.

[0120] Table 1: Processing conditions and data for brominated butyl rubber (Experiment 1)

[0121]

[0122] Table 2: Processing conditions and data for brominated butyl rubber (Experiment 2)

[0123]

[0124] Interestingly, surfactants were found to play a crucial role in promoting H2O2 utilization during the regeneration bromination process. At a peroxide to bromine molar ratio of 0.2 (H2O2:Br2), the negative impact on H2O2 conversion was negligible without surfactant use or surfactant injection during regeneration, as the H2O2 conversion was calculated to be approximately 90% based on O2 measurements in the system exhaust gas. However, at a peroxide to bromine molar ratio of 0.4 (H2O2:Br2), a significant decrease in H2O2 conversion was observed without surfactant use or surfactant injection, as the conversion was calculated to be approximately 60%. Upon establishing or re-establishing surfactant flow, the H2O2 conversion immediately increased to nearly 100% without any other process intervention. Not wanting to be bound by theory, surfactants contribute to the formation of more stable dispersions (e.g., multiphase mixtures) in the halogenation reactor 314. Therefore, aqueous H2O2 solutions can be well dispersed within a continuous hydrocarbon phase (e.g., an adhesive). In addition, a more stable dispersion allows for an increase in the surface area between the aqueous and hydrocarbon phases, which in turn promotes the migration of HBr from the hydrocarbon phase to the aqueous phase for halogen regeneration.

[0125] Functionalized bromine determination

[0126] The PLS model was used to correlate FTIR spectral regions corresponding to the structures and / or components of interest with NMR data to determine the amount of functionalized bromine in the brominated polymer products. The calibration set was prepared from standard samples with known concentrations obtained by NMR, and a macro model was developed to automatically calculate the mol% of the bromide structure after collecting the spectra. The obtained values ​​are summarized in Tables 3 and 4.

[0127] Table 3: Functionalized bromine content (Experiment 1)

[0128]

[0129] Table 4: Functionalized bromine content (Experiment 2)

[0130]

[0131] As shown in Tables 3 and 4, Experiments 1 and 2 produced brominated butyl elastomers with comparable bromine content and structure.

[0132] Table 5: Residual salt content in the resulting wastewater (Experiment 2)

[0133]

[0134] As shown in Table 5, the halogen regeneration process in Experiment 2 resulted in a reduction in the salt content removed from the wastewater generated by the method disclosed herein. This reduction in the salt content (e.g., bromide salts) found in the resulting wastewater further illustrates the reduced risk of environmental impact associated with this method.

[0135] Mooney viscosity measurement

[0136] Initial Mooney viscosity was measured on brominated butyl elastomer samples within 1 hour of separation. The brominated butyl elastomer samples were aged in an air-circulating oven at 80°C for approximately 7–10 days. Samples aged at 80°C for 5 days were expected to exhibit properties similar to brominated butyl elastomers under warehouse conditions for 1 year. Samples aged at 80°C for 7 days were expected to exhibit properties similar to brominated butyl elastomers under warehouse conditions for 2 years. Samples were taken at 80°C at intervals of 0, 1, 3, 7, and 10 days, and Mooney viscosity was tested according to ASTM 1646. The change in Mooney viscosity was calculated to determine how it changes with aging. The aged Mooney viscosity was measured on the segregated brominated butyl elastomer samples before oven aging and after approximately 7 days of oven aging at approximately 80°C (simulating long-term storage conditions accelerated by using temperatures above ambient). Table 2 summarizes the Mooney viscosity of each test sample throughout the aging process at different time intervals. Table 3 summarizes the change in Mooney viscosity of each test sample throughout the aging process at different time intervals.

[0137] Table 5: Mooney viscosity throughout the aging process (Experiment 1)

[0138]

[0139] Table 6: Changes in Mooney viscosity throughout the aging process (Experiment 1)

[0140]

[0141] Table 7: Mooney viscosity throughout the aging process (Experiment 2)

[0142]

[0143] Table 8: Changes in Mooney viscosity throughout the aging process (Experiment 2)

[0144]

[0145] It has been determined that the Mooney stability of halogenated butyl elastomers developed via the methods disclosed herein is similar to that of those from conventional methods. In other words, the Mooney viscosity increase of halogenated butyl elastomers produced by the regenerated halogenation method disclosed herein is comparable to that produced by conventional methods (as illustrated in Tables 6 and 8). Therefore, even with low residence times and high concentrations of brominated adhesives, the regenerated products from the methods disclosed herein do not exhibit an increased Mooney viscosity increase (also known as Mooney run) when compared with control samples under all regeneration conditions.

[0146] Liner compound mixture

[0147] Compounds for application research and evaluation of physical and mechanical properties were prepared using a typical liner formulation (Table 9) prepared using a Banbury mixer. Mixing was carried out in a 1.6-liter Banbury mixer with a fill factor of 80% and a rotor speed of 70 rpm. The masterbatch density was ~1.11 g / cc, therefore, the batch weight for non-productive (NP) masterbatch and final mix was 1423 g. The polymer (or multiple polymers) was introduced into the mixer at time t=0 and masticated for 30 seconds; at time t=30 seconds, 2 / 3 of the carbon black was added; at t=120 seconds, chemicals (thickening agent, homogenizing resin, anti-scorching agent, oil) were added; this was followed by a plunger sweep cleaning cycle at time t=210 seconds; the NP masterbatch was discharged at 135°C. The total NP mixing time was approximately 5 minutes; in all cases, the mix was discharged according to controlled times. For the final batch, the fill factor was maintained at ~77% and the rotor speed at 40 rpm. To prepare the final batch, the masterbatch and curing agents (zinc oxide, sulfur, MBTS) were loaded into the mixer at time t=0; a plunger scan was performed at time t=60 seconds. The final batch was discharged at <100°C. The total final batch mixing time was 2 minutes. The discharge from the mixer was passed through a twin-roll mill twice to prepare a thick pad. Test samples for property evaluation were prepared using sheet rubber compound.

[0148] Table 9: Typical formulations for lining components

[0149]

[0150] Physical and mechanical properties

[0151] The material hardness was measured according to ASTM D2240. The arithmetic mean of five samples—original, steam-aged, and heat-aged—is reported. The material mechanical properties were measured according to ASTM D412, with the mean of three compound specimens—original, heat-aged, and steam-aged—reported. The material tear strength was determined according to ASTM D624, with the mean of three compound specimens—original, heat-aged, and steam-aged—reported. Samples were tested before oven aging and after oven aging at approximately 125°C for approximately 3 days (simulating long-term storage conditions accelerated by using temperatures above ambient).

[0152] The physical and mechanical properties of the halogenated butyl elastomers disclosed herein were measured before and after material aging to determine the retention of material properties. These physical and mechanical properties are summarized in Tables 10 and 11.

[0153] Table 10: Physical and mechanical properties throughout the aging process (Experiment 1)

[0154]

[0155] Table 11: Physical and mechanical properties throughout the aging process (Experiment 2)

[0156]

[0157] It has been determined that the physical and mechanical properties of the halogenated butyl elastomers prepared by the methods disclosed herein are comparable to those of conventional halogenation methods (as illustrated in Tables 10 and 11).

[0158] In summary, the regenerative halogenation method disclosed herein provides a simple yet effective route for developing halogenated butyl elastomers with Mooney viscosity growth and retention of physical properties comparable to elastomers formed by conventional halogenation methods. Furthermore, stable dispersions in the halogenation reactor can be obtained. The method disclosed herein allows for low residence times and high concentrations of halogenated adhesives without compromising the Mooney stability of the halogenated butyl elastomers.

[0159] Unless otherwise specified, the phrase “consistently of…” does not exclude the presence of other steps, elements or materials (whether or not specifically mentioned in the specification), provided that such steps, elements or materials do not affect the fundamental and novel characteristics of this disclosure, and furthermore, they do not exclude impurities and variations generally associated with the elements and materials used.

[0160] For simplicity, only certain numerical ranges are explicitly disclosed in this document. However, a lower limit can be combined with any other upper limit to define a range that is not explicitly stated, and similarly, a lower limit can be combined with any other lower limit to define a range that is not explicitly stated; likewise, an upper limit can be combined with any upper limit to define a range that is not explicitly stated. Furthermore, even if not explicitly stated, every point or individual value between the two endpoints is included within the range. Therefore, each point or individual value itself can serve as a lower or upper limit, combined with other points or individual values ​​or other lower or upper limits to define a range that is not explicitly stated.

[0161] All literature described herein, including any priority documents and / or experimental procedures, is incorporated herein by reference to all rights, without contradicting this document. It will be apparent from the foregoing overview and specific embodiments that, while the form of this disclosure has been illustrated and described, various modifications may be made without departing from the spirit and scope of this disclosure. Therefore, it is not intended that this disclosure be limited thereto. Similarly, the term “comprising” is considered synonymous with the term “including” for the purposes of U.S. law. Likewise, whenever a composition, element, or group of elements precedes the transitional term “comprising,” it should be understood that the same composition or group of elements preceding the listed composition, element, or elements, and vice versa, is also considered.

[0162] Although this disclosure has been described in accordance with many embodiments and examples, those skilled in the art will understand after reading this disclosure that other embodiments may be devised without departing from the scope and spirit of this disclosure.

Claims

1. Methods, including: An aqueous solution is introduced together with a first hydrocarbon solvent to form an emulsion, wherein the aqueous solution contains an oxidant and a surfactant; An adhesive is introduced together with the emulsion to form a first mixture in a reactor, wherein the adhesive comprises a butyl rubber elastomer and a second hydrocarbon solvent that is the same as or different from the first hydrocarbon solvent; A halogen source is introduced together with the first mixture contained in the reactor to form a second mixture containing a halogenated butyl rubber elastomer; The neutralizing agent is introduced together with the second mixture to form a third mixture; and The halogenated butyl rubber elastomer is separated from the third mixture.

2. The method of claim 1, wherein the oxidizing agent-containing solution is an aqueous solution containing about 30% to about 40% by weight of an oxidizing agent.

3. The method of claim 1, wherein the surfactant comprises an ethoxylated alcohol emulsifier.

4. The method of claim 2, wherein the oxidant is hydrogen peroxide.

5. The method of claim 1, wherein the aqueous solution comprises an input ratio of surfactant to oxidant of about 1:100 (lbs surfactant:lbs oxidant) to about 3.8:

100.

6. The method of claim 1, wherein the first hydrocarbon solvent is selected from pentane, hexane, heptane, and combinations thereof.

7. The method of claim 1, wherein the formation of the second mixture comprises a halogenation reaction in which the halogen source and the first mixture contained in the reactor have a residence time of about 0.5 minutes to about 60 minutes.

8. The method of claim 1, wherein the butyl rubber elastomer comprises about 18% to about 35% by weight of the adhesive.

9. The method of claim 1, wherein the second hydrocarbon solvent is selected from pentane, hexane, heptane, and combinations thereof.

10. The method of claim 1, wherein the halogen source is Br2.

11. The method of claim 10, wherein the ratio of peroxide to bromine (mol:mol) is about 0.3:1 to about 0.8:

1.

12. The method of claim 10, wherein the ratio of bromine to rubber is about 18 kg / ton to about 45 kg / ton.

13. Methods, including: An aqueous solution is introduced together with a first organic solvent to form an emulsion, wherein the aqueous solution contains an oxidant and a surfactant; An adhesive is introduced together with the emulsion to form a first mixture in a reactor, wherein the adhesive comprises a butyl rubber elastomer and a second organic solvent; A halogen source is introduced together with the first mixture contained in the reactor to form a second mixture, wherein forming the second mixture further includes carrying out a halogenation reaction, the halogenation reaction comprising: The halogen source is reacted with the butyl rubber elastomer to form an initial halogenated butyl rubber elastomer and hydrogen halide. The hydrogen halide reacts with the oxidant to form a free halide, and Continue the halogenation reaction to produce additional halogenated butyl rubber elastomers; The neutralizing agent is introduced together with the second mixture to form a third mixture; and Separate the initial halogenated butyl rubber elastomer and / or the additional halogenated butyl rubber elastomer from the third mixture.

14. The method of claim 13, wherein the halogen source is Br2.

15. The method of claim 14, wherein the bromine utilization rate of the halogenation reaction is from about 60% to about 90%.

16. The method of claim 14, wherein the residence time of the halogenation reaction is from about 1 minute to about 25 minutes.

17. The method of claim 14, wherein the halogenation reaction is carried out at a temperature of about 20°C to about 70°C.

18. The method of claim 14, wherein the halogenated butyl elastomer has an initial Mooney viscosity of about 20 MU to about 50 MU (as determined by ASTM D1646).

19. The method of claim 14, wherein the halogenated butyl elastomer has a Mooney viscosity increase of about 2.5 MU to about 5 MU (as determined by ASTM D1646) when aged at about 80°C for 7 days.

20. Methods, including: An aqueous solution is introduced together with a first hydrocarbon solvent to form an emulsion, wherein the aqueous solution contains an oxidant and a surfactant; An adhesive is introduced into the emulsion to form a first mixture within a reactor, wherein the adhesive comprises a butyl rubber elastomer and a second hydrocarbon solvent that is the same as or different from the first hydrocarbon solvent; HBr is introduced into a reactor containing the first mixture to form a second mixture containing a halogenated butyl rubber elastomer; The neutralizing agent is introduced together with the second mixture to form a third mixture; and The halogenated butyl rubber elastomer is separated from the third mixture.

21. Methods, including: An aqueous solution is introduced together with a first organic solvent to form an emulsion, wherein the aqueous solution contains an oxidant and a surfactant; An adhesive is introduced together with the emulsion to form a first mixture in a reactor, wherein the adhesive comprises a butyl rubber elastomer and a second organic solvent; A halogen source is introduced together with the first mixture contained in the reactor to form a second mixture, such that the molar ratio of oxidant to halogen is about 0.2:1 to about 0.8:1, wherein forming the second mixture further includes carrying out a halogenation reaction, the halogenation reaction comprising: The halogen source is reacted with the butyl rubber elastomer to form an initial halogenated butyl rubber elastomer and hydrogen halide. The hydrogen halide reacts with the oxidant to form a free halide, and Continue the halogenation reaction to produce additional halogenated butyl rubber elastomers; The neutralizing agent is introduced together with the second mixture to form a third mixture; and The initial halogenated butyl rubber elastomer and / or the additional halogenated butyl rubber elastomer are separated from the third mixture to form a waste mixture, wherein the waste mixture contains about 2,000 mg / L to about 2,650 mg / L of dissolved solids.

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