WO2023000095A1 - Branched polyisobutylene polymers - Google Patents

Abstract

A process for producing a branched polyisobutylene polymer involves polymerizing isobutylene in the presence of a branching agent, the branching agent being a polyfarnesene having 5 or more farnesene units. The resulting branched polymer has improved green strength and creep compliance. The polyfarnesene may be a homopolymer having a number average molecular weight in a range of 1,000-130,000 g/mol. Alternatively, the polyfarnesene can be a copolymer comprising a comonomer such as a conjugated diene or a styrene. The branched polyisobutylene polymer products are useful for the manufacture of articles such as seals, gaskets, adhesives, chewing gum, roofing material, or viscosity modifiers.

Description

BRANCHED POLYISOBUTYLENE POLYMERS

Cross-reference to Related Applications

This application claims priority to European patent application 21186987 filed July 21, 2021 and European patent application 21188259 filed July 28, 2021, the entire contents of which are herein incorporated by reference.

Field

This application relates to polymers and processes for producing polymers, in particular to branched isoolefin polymers, processes for producing the same and rubber compounds produced therefrom.

Background

Commercial polyisoolefins, as well as their halogenated analogues, are mostly linear polymers, and for the case of butyl rubber (HR), the level of branching or linearity is dictated primarily by the amount of isoprene that is added to the reactor. For a given molecular weight, the level of linearity for HR can range from what is observed in polyisobutylene (PIB) to commercial polymers with higher isoprene loadings (e.g., with 2.25 mol% isoprene). Without adding a branching agent, increasing the isoprene beyond 3-4 mol% will poison the polymerization reaction too much, lowering molecular weight substantially.

Branched polyisoolefins are generally obtained by adding a reagent that is active in cationic polymerization and leads to termination of a propagating polymer chain onto the branching agent. The branching agent is required to have unsaturation that allows the growing polymer chains to react with the additive.

Branched polyisoolefin polymers have been commercially available in several forms for decades. Polyisoolefin polymers have been produced using divinylbenzene (DVB) as a crosslinking/branching agent. The product was cross-linked (20-80%) and was mostly used in adhesives. Production of DVB crosslinked polyisoolefin polymers is undesirable due to environmental concerns around the use of DVB.

A starbranched bromobutyl rubber (EMC 6222, Exxon Mobil Corporation) has been produced commercially, which is mainly used in tire innerliner compounds. The commercial starbranched bromobutyl rubber uses a styrene-butadiene-styrene (SBS) resin as the branching agent, giving a starbranched fraction and a linear fraction. The combination of the two fractions imparts good green strength, reduced cold flow and creep, while also maintaining processability.

The proposed reactivity of the SBS resin is much different to the reactivity of DVB. With DVB, the propagating butyl polymer chain grows through the vinyl groups, giving a long chain HR with an additional pendant vinyl group. This second vinyl group can participate in the propagation of a second growing chain, leading to a crosslinked polymer with a higher molecular weight than the parent material without DVB. With the SBS resin added to the polymerization, the growing polymer chains terminate onto the unsaturated butadiene portion of the SBS resin, leading to multiple HR chains being attached to a single chain of SBS, giving rise to the star branched structure. In this case, rather than multiple full length HR chains being fused together (as with DVB), multiple shorter chains terminate onto the resin, which gives a fraction with a higher molecular weight, but one that is not crosslinked.

There remains a need for highly efficient branching agents that can be used to produce branched isoolefin polymers having desirable properties for various applications.

Summary

A polyfarnesene having 5 or more farnesene units can be used as a branching agent for producing a branched isoolefin polymer. The branched isoolefin polymer, and halogenated branched isoolefin polymer produced therefrom, have reduced cold flow and improved green strength.

Described herein is a process for producing a branched isoolefin polymer comprising polymerizing at least one isoolefin monomer in a reaction mixture in presence of a branching agent, the branching agent comprising a polyfarnesene having 5 or more farnesene units.

Also described herein is a branched isoolefin polymer comprising isoolefin units and farnesene units.

Also described herein is a rubber compound comprising the branched isoolefin polymer and a filler.

In comparison to the use of the SBS resin branching agent, the present process requires less branching agent on a weight basis to produce branched unsaturated isoolefin copolymers having desirably reduced cold flow and improved green strength, which leads to less impurities in the resulting polymer, which is highly desirable in pharmaceutical applications. Further, the branched isoolefin polymer, and halogenated branched isoolefin polymer produced therefrom, have higher levels of chain branching in comparison to star branched polymers produced with the SBS resin and similar branching agents, and halogenated polymers produced therefrom.

One or more of the following further features and benefits are obtained using a polyfarnesene as a branching agent. Higher green strength at equivalent Mooney viscosity is realized, therefore improving milling and calendaring operations. Less creep at equivalent Mooney viscosity and unsaturation is realized, therefore leading to less cold flow for raw polymer and mixed compounds. The polyfarnesene branching agent is biosourced, therefore leading to a sustainable process, which is useful for all applications. The polyfarnesene is a more effective branching agent, therefore providing less loading in the produced polymer leading to less potential for extractables and higher level of incorporation in the produced polymer. The polyfarnesene introduces an alternative monomer into the produced polymer, therefore leading to new properties. Different rheological behavior of uncurable polymers is realized, therefore providing a different mouthfeel/behavior, which is particularly useful for chewing gum applications and applications as thickeners.

Further features will be described or will become apparent in the course of the following detailed description. It should be understood that each feature described herein may be utilized in any combination with any one or more of the other described features, and that each feature does not necessarily rely on the presence of another feature except where evident to one of skill in the art.

Brief Description of the Drawings

For clearer understanding, preferred embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:

Fig. 1 depicts a van Gurp-Palmen plot of a lab-prepared butyl rubber control (Control) prepared without branching agent, a starbranched bromobutyl rubber and lab- prepared branched butyl rubbers prepared using varying amounts of a polyfarnesene (Krasol™ F 3000).

Fig. 2 depicts a van Gurp-Palmen plot of a starbranched bromobutyl rubber and lab-prepared branched butyl rubbers (PF-IIR Solution 1 and PF-IIR Solution 2) prepared using a polyfarnesene (Krasol™ F 3000) in two recipes determined using design of experiment (DoE) based on the results shown in Fig. 1. Fig. 3 depicts a graph of creep compliance (Pa-1) versus time (s) of lab-prepared branched butyl rubbers (PF-IIR Solution 1 and PF-IIR Solution 2) prepared using a polyfarnesene (Krasol™ F 3000) and commercial butyl rubbers (ARL RB100 and RB402).

Fig. 4 depicts a stress-strain plot of lab-prepared branched butyl rubbers (PF-IIR Solution 1 and PF-IIR Solution 2) prepared using a polyfarnesene (Krasol™ F 3000) and commercial butyl rubbers (ARL RB100 and RB402).

Fig. 5 depicts a van Gurp-Palmen plot of a commercial polyisobutylene control (Control) prepared without branching agent, lab-prepared branched polyisobutylene polymers prepared using varying amounts of a polyfarnesene (Krasol™ F 3000) and branched butyl rubbers also prepared using a polyfarnesene (Krasol™ F 3000).

Fig. 6 depicts a van Gurp-Palmen plot of lab-prepared branched poly(isobutylene- co-paramethylstyrene) (IB-co-pMS) using a polyfarnesene (Krasol™ F 3000) branching agent, a brominated poly(isobutylene-co-paramethylstyrene) (BIB-co-pMS), a starbranched bromobutyl rubber, a lab-prepared butyl rubber and a lab-prepared branched butyl rubber using a polyfarnesene (Krasol™ F 3000) branching agent.

Fig. 7 depicts a van Gurp-Palmen plot of comparative runs where lab-prepared branched butyl rubbers were produced with different polyfarnesene polymers with varying molecular weight and enchainment.

Fig. 8 depicts a van Gurp-Palmen plot of butyl rubber controls (Control) prepared without a branching agent, butyl rubber products produced from a polyfarnesene (Krasol™ F 3000) and from other cyclic polyterpenes (poly-a-pinene and poly-d- limonene) as branching agents for butyl rubber polymerization.

Fig. 9 depicts a van-Gurp-Palmen plot of isobutylene-type polymers produced using a solution polymerization process, including branched polymers produced using a polyfarnesene (Krasol™ F 3000) branching agent and controls which did not contain a branching agent.

Fig. 10 depicts a van Gurp-Palmen plot of a commercial polyisobutylene control (Control) prepared without branching agent, lab-prepared branched polyisobutylene polymers prepared using varying amounts of a polyfarnesene (Krasol™ F 3000) and branched butyl rubbers also prepared using a polyfarnesene (Krasol™ F 3000).

Fig. 11 depicts a van Gurp-Palmen plot of control and branched polyisobutylenes generated using polyfarnesenes of various molecular weight and composition. Fig. 12 depicts a van Gurp-Palmen plot of control polyisobutylene and PIBs generated using polyfarnesene and hydrogenated polyfarnesene.

Fig. 13 depicts a van Gurp-Palmen plot of a control and a polyfarnesene-branched polyisobutylene polymer produced by solution polymerization in hexane.

Fig. 14 depicts a ¹H NMR spectrum of polyfarnesene (bottom), lab-produced polyisobutylene (middle) and lab-produced PF-PIB (top).

Fig. 15 depicts a pyrolysis-GCMS chromatogram of PF-PIB (top, black), polyfarnesene (middle, light grey) and PIB N50 (bottom, dark grey).

Fig. 16 depicts a GPC chromatogram of PIB N100 and PF-PIB.

Fig. 17 depicts creep compliance versus time of commercial PIB grades and labprepared PF-PIB recipes.

Fig. 18 depicts creep compliance data showing decrease in creep compliance (improved stability) as samples were aged for PF-PIB while commercial PIB samples generally increased (worse stability).

Fig. 19 depicts a viscosity vs shear rate amplitude plot generated using an RPA at 200°C of commercial and lab produced polyisobutylene samples.

Fig. 20 depicts a mixer torque curve of uncured PIB in window seal compounds.

Fig. 21 depicts a tan delta (frequency sweep at 100 °C) plot of uncured window seal compounds with PIB, showing improved processability with higher tan delta.

Fig. 22 depicts a Payne effect (strain sweep at 60 °C) plot of uncured window seal compounds with PIB, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 23 depicts a stress-extension plot of combined uncured window seal compounds with PIB using the T2000 tensile instrument.

Fig. 24 depicts a mixer torque curve of uncured PIB in black sheeting compounds.

Fig. 25 depicts a tan delta (frequency sweep at 100 °C) plot of uncured black sheeting compounds with PIB, showing improved processability with higher tan delta. Fig. 26 depicts a Payne effect (strain sweep at 60 °C) plot of uncured black sheeting compounds with PIB, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 27 depicts a stress-extension plot of combined uncured black sheeting compounds with PIB using the T2000 tensile instrument.

Fig. 28 depicts unaged vs aged (dotted lines) black sheeting compounds tested on the T2000 tensile instrument, demonstrating that linear, commercial PIBs harden over time.

Fig. 29 depicts unaged vs aged (dotted lines) black sheeting compounds tested on the T2000 tensile instrument, demonstrating that the majority of PF-PIB samples soften overtime.

Detailed Description

Production of the isoolefin polymer involves polymerizing at least one isoolefin monomer in an organic diluent in the presence of an initiator system (a Bransted acid or a Lewis acid catalyst and a proton source) capable of initiating the polymerization process. Polymerization occurs in a polymerization reactor. Suitable polymerization reactors include, for example, flow-through polymerization reactors, plug flow reactor, moving belt or drum reactors, and the like. The process may be a continuous or batch process. In a preferred embodiment, the process is a continuous polymerization process. The process may comprise slurry or solution polymerization of the monomers.

Isoolefin polymers (i.e., polyisoolefins) comprise repeating units derived from an isoolefin monomer. In some embodiments, the isoolefin polymers comprise repeating units derived from one isoolefin monomer and repeating units derived from at least one copolymerizable monomer.

Suitable isoolefin monomers include hydrocarbon monomers having 4 to 16 carbon atoms. In one embodiment, the isoolefin monomer has from 4 to 7 carbon atoms. Examples of suitable isoolefins include isobutene (isobutylene), 2-methyl-1-butene, 3- methyl-1-butene, 2-methyl-2-butene, 4-methyl-1-pentene and 4-methyl-1-pentene. A preferred isoolefin monomer is isobutene (isobutylene).

Suitable copolymerizable monomers comprise one or more of a different isoolefin monomer from the one isoolefin monomer and a copolymerizable unsaturated monomer that is not an isoolefin. Copolymerizable unsaturated monomers that are not isoolefins include, for example, multiolefin monomers, styrenic monomers, b-pinene, cyclopentadiene, methylcyclopentadiene, indene and the like.

Multiolefin monomers include, for example, hydrocarbon monomers having 4 to 14 carbon atoms. In some embodiments, the multiolefin monomers are conjugated dienes. Examples of suitable conjugated diene monomers include butadiene, 2-methyl-1,3- butadiene (isoprene), 2,4-dimethylbutadiene, piperylene, 3-methyl-1,3-pentadiene, 2,4- hexadiene, 2-neopentylbutadiene, 2-methyl-1 ,5-hexadiene, 2,5-dimethyl-2,4-hexadiene, 2-methyl-1,4-pentadiene, 4-butyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 2,3- dibutyl-1,3-pentadiene, 2-ethyl-1,3-pentadiene, 2-ethyl-1, 3-butadiene, 2-methyl-1,6- heptadiene, cyclopentadiene, methylcyclopentadiene, cyclohexadiene, 1-vinyl- cyclohexadiene and mixtures thereof. A preferred conjugated diene is isoprene.

Styrenic monomers include, for example, alkyl-substituted vinyl aromatic co monomers, including but not limited to a Ci-C₄ alkyl substituted styrene. Some examples of styrenic monomers are styrene, a-methylstyrene, p-methylstyrene and chlorostyrene. A preferred styrenic monomer is p-methylstyrene.

In some embodiments, the isoolefin polymer is a terpolymer of isoolefin with two other different copolymerizable monomers.

In some embodiments, the isoolefin polymer is an unsaturated isoolefin copolymer. The unsaturated isoolefin copolymer is formed by copolymerization of a monomer mixture. Preferably, the monomer mixture comprises about 80-99.9 mol% of at least one isoolefin monomer and about 0.1-20 mol% of at least one multiolefin monomer, based on the monomers in the monomer mixture. More preferably, the monomer mixture comprises about 90-99.9 mol% of at least one isoolefin monomer and about 0.1-10 mol% of at least one multiolefin monomer. In one embodiment, the monomer mixture comprises about 92.5-97.5 mol% of at least one isoolefin monomer and about 2.5-7.5 mol% of at least one multiolefin monomer. In another embodiment, the monomer mixture comprises about 97.4-95 mol% of at least one isoolefin monomer and about 2.6-5 mol% of at least one multiolefin monomer. When a multiolefin monomer is used, the monomer mixture may also comprise from 0.01% to 1% by weight of at least one multiolefin cross-linking agent, and when the multiolefin cross-linking agent is present, the amount of multiolefin monomer is reduced correspondingly. The at least one multiolefin monomer is preferably a conjugated diene. If the monomer mixture comprises an additional copolymerizable monomer that is not a multiolefin, the additional copolymerizable monomer preferably replaces a portion of the multiolefin monomer. Some preferred isoolefin polymers are polyisobutylene (PIB), which is a polymer of isobutylene, poly(isobutylene-co-isoprene) (HR) also called butyl rubber, which is a copolymer of isobutylene and isoprene, and poly(isobutylene-co-paramethylstyrene) (IMS), which is a copolymer of isobutylene and p-methylstyrene.

Suitable organic diluents may include, for example, alkanes, chloroalkanes, cycloalkanes, aromatics, hydrofluorocarbons (HFC) or any mixture thereof. Chloroalkanes may include, for example methyl chloride, dichloromethane or any mixture thereof. Methyl chloride is particularly preferred. Alkanes and cycloalkanes may include, for example, isopentane, cyclopentane, 2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylpentane, 3- methylpentane, n-hexane, methylcyclopentane, 2,2-dimethylpentane or any mixture thereof. Alkanes and cycloalkanes are preferably C6 solvents, which include n-hexane or hexane isomers, such as 2-methyl pentane or 3-methyl pentane, or mixtures of n-hexane and such isomers as well as cyclohexane. The monomers are generally polymerized cationically in the diluent at temperatures in a range of from -120°C to +20°C, preferably -100°C to -50°C, more preferably -95°C to -65°C. The temperature is preferably about -70°C or colder or -80°C or colder.

The initiator system comprises a Bransted acid or a Lewis acid catalyst and a proton source. The Lewis acid catalyst preferably comprises aluminum trichloride (AICI₃). Alkyl aluminum halide catalysts are also useful for catalyzing the polymerization reaction. Examples of alkyl aluminum halide catalysts include methyl aluminum dibromide, methyl aluminum dichloride, ethyl aluminum dibromide, ethyl aluminum dichloride, butyl aluminum dibromide, butyl aluminum dichloride, dimethyl aluminum bromide, dimethyl aluminum chloride, diethyl aluminum bromide, diethyl aluminum chloride, dibutyl aluminum bromide, dibutyl aluminum chloride, methyl aluminum sesquibromide, methyl aluminum sesquichloride, ethyl aluminum sesquibromide, ethyl aluminum sesquichloride and any mixture thereof. Preferred of alkyl aluminum halide catalysts are diethyl aluminum chloride (Et₂AICI or DEAC), ethyl aluminum sesquichloride (EtisAICh s or EASC), ethyl aluminum dichloride (EtAICh or EADC), diethyl aluminum bromide (Et₂AIBr or DEAB), ethyl aluminum sesquibromide (EtisAIBr s or EASB) and ethyl aluminum dibromide (EtAIBr₂ or EADB) and any mixture thereof. A particularly preferred alkyl aluminum halide catalyst comprises ethyl aluminum sesquichloride, preferably generated by mixing equimolar amounts of diethyl aluminum chloride and ethyl aluminum dichloride, preferably in a diluent. The diluent is preferably the same one used to perform the copolymerization reaction. The proton source when a Lewis acid is the catalyst includes any compound that will produce a proton when added to the catalyst or a composition containing the catalyst. Protons are generated from the reaction of the catalyst with proton sources to produce the proton and a corresponding by-product. Proton sources include, for example, water (H2O), alcohols, phenols, thiols, carboxylic acids, and the like or any mixture thereof.

Water, alcohol, phenol or any mixture thereof is preferred. The most preferred proton source is water. A preferred ratio of catalyst to proton source is from 5:1 to 100:1 by weight, or from 5:1 to 50:1 by weight. The initiator system is preferably present in the reaction mixture in an amount providing 0.0007-0.02 wt% of the catalyst, more preferably 0.001-0.008 wt% of the catalyst, based on total weight of the reaction mixture.

The initiator system is dissolved in an organic solvent to produce an initiator solution, which is then contacted with the reaction mixture to initiate polymerization of the monomers. The organic solvent may comprise any of the organic diluents described above. Preferably, the organic solvent comprises a polar organic solvent. Methyl chloride is particularly preferred. The catalyst is preferably present in the initiator solution at a concentration of 0.01 wt% to 0.6 wt%, based on total weight of the initiator solution, more preferably 0.05 wt% to 0.6 wt%, 0.075 wt% to 0.5 wt% or 0.1 wt% to 0.4 wt%. The initiator system is preferably soluble in the reaction mixture.

The branching agent comprises a polyfarnesene. Polyfarnesenes can be prepared by anionic polymerization of farnesene monomers. Polyfarnesenes have been used in the past as processing additives after polymerization is complete. Farnesene monomers are terpenes and exist in a number of different isomeric forms. The chemical structures of the isomers of farnesene are shown in Scheme 1. Commercial farnesene generally exists as an approximately 1:1 mixture of (E,E)-a- and trans-p-farnesene with other isomers present as minor impurities.

Scheme 1: Structural Isomers of Farnesene Both of the major isomers of farnesene have been found through experimentation to poison polymerization reactions involving the polymerization of an isoolefin monomer. The presence of either of the major farnesene isomers in the polymerization reaction mixture, even in small amounts, resulted in molecular weight reductions of the polymers of about 200,000 g/mol and yield reductions of about 10% despite the addition of more initiator. Chromatograms from GPC analysis demonstrated no high molecular weight shoulder, but instead a very small peak of high molecular weight, suggesting initiation in the presence of monomeric farnesene results in a relatively normal polymerization of the isoolefin monomer (i.e., little or no branching) together with another fraction of “polyfarnesene” that is generated cationically, thereby further confirming that both major isomers of farnesene poison isoolefin polymerizations.

It has now been found that the presence of a polyfarnesene having 5 or more farnesene units (i.e., a degree of polymerization (DP) of 5 or more) in a reaction mixture for the polymerization of an isoolefin monomer leads to the generation of a branched isoolefin polymer product, in stark contrast to the monomeric farnesene. Further, the branching effectiveness of such polyfarnesenes is much higher than that of the styrene- butadiene-styrene (SBS) resin and similar branching agents mentioned above. In comparison to polyfarnesenes, loadings of 30 times or more of the SBS per polymerization of similar scale are required to give a branched product, the product even having less branching, as per rheological measurements, than the product obtained with the use of polyfarnesenes as the branching agent. Further, to achieve similar rheological characteristics in comparison to the use of SBS resin, the weight amount of polyfarnesene used as branching agent can be 10 or more times less than the amount of SBS resin.

Preferably, the polyfarnesene comprises from 5 to 640 farnesene units, more preferably 5 to 425 farnesene units, yet more preferably 15 to 105 farnesene units.

The polyfarnesene may be a homopolymer or a copolymer. Polyfarnesene homopolymers preferably have an average number average molecular weight (M_n) in a range of 1,000-130,000 g/mol, more preferably 1,000-85,000 g/mol, yet more preferably 3,000-21,000 g/mol. The polyfarnesene may be a copolymer comprising at least one comonomer. The at least one comonomer preferably comprises a conjugated diene or a styrenic. Conjugated dienes and styrenics may be selected from the list of conjugated dienes and styrenics provided above in connection with the at least one copolymerizable monomer. Preferably, the at least one comonomer comprises isoprene, 1,3-butadiene, piperylene, styrene, a-methylstyrene, p-methylstyrene, ocimene or myrcene. The at least one comonomer is preferably present in the polyfarnesene copolymer in an amount in a range of 1-75 mol%, for example 1-49 mol%.

The polyfarnesene may be a 1,4-co-1 ,2-addition polymer or solely a 1 ,4-polymer. The polyfarnesene may be linear or branched (e.g., star branched). The polyfarnesene may be terminated with a functional group or not terminated with a functional group. The terminal functional group may be hydroxy, carboxy or the like, especially hydroxy- terminated. Table 1 provides some known grades of polyfarnesene.

Table 1

The polyfarnesene is preferably derived from farnesene comprising at least 95 mol% of trans-p-farnesene. Scheme 2 illustrates the structures of trans-p-farnesene and a polyfarnesene derived from farnesene comprising at least 95 mol% of trans-p- farnesene. The resulting polyfarnesene is generally a mixture of addition isomers, a 1,4- isomer and a 1 ,2-isomer, which gives rise to the bottle-brush structure illustrated in Scheme 2.

Scheme 2: Structures of Trans-p-farnesene and a Polyfarnesene Derived Therefrom

11

RECTIFIED SHEET (RULE 91.1) The polyfarnesene is introduced into the reaction mixture before polymerization is complete. Preferably, the polyfarnesene is introduced into the reaction mixture before initiation, at initiation or shortly after initiation of the polymerization. The branching agent can be introduced neat to the reaction mixture, but is preferably introduced into the reaction mixture as a solution in a solvent, preferably an organic solvent, for example methyl chloride, dichloromethane, hexane, cyclohexane or mixtures thereof. Control of the level of branching can be achieved by adjusting the amount of the polyfarnesene in the reaction mixture. The branching agent is preferably present in the reaction mixture in a minimum amount of 0.01 wt%, based on weight of the isoolefin monomer in the reaction mixture. In some embodiments, the minimum amount may be 0.03 wt% or 0.05 wt%. The branching agent may be present in the reaction mixture in a maximum amount of 2 wt%, based on weight of the isoolefin monomer in the reaction mixture. In some embodiments, the maximum amount may be 1.5 wt% or 1.25 wt% or 1 wt% or 0.8 wt%. In some embodiments, the amount of branching agent may be 0.01-2 wt% or 0.01-1.5 wt% or 0.01-1 wt% or 0.01-0.8 wt%.

Likewise, the branched isoolefin polymer that is produced preferably comprises up to 2 wt% of farnesene units, based on weight of the isoolefin units in the polymer. Preferably, the minimum content of farnesene units is 0.01 wt%. In some embodiments, the minimum amount may be 0.03 wt% or 0.05 wt%. In some embodiments, the maximum amount may be 1.5 wt% or 1.25 wt% or 1 wt% or 0.8 wt%. In some embodiments, the content of farnesene units may be 0.01-2 wt% or 0.01-1.5 wt% or 0.01- 1 wt% or 0.01-0.8 wt%.

In some embodiments, a chain transfer agent can be added to the reaction mixture. The chain transfer agent further controls the rheology of the resulting isoolefin polymer by controlling the level of branching and the number of short chains in the isoolefin polymer. The chain transfer agent improves processibility of the isoolefin polymer produced in the process by reducing the average molecular weight of the isoolefin polymer. The chain transfer agent preferably comprises diisobutylene, piperylene, 1-methylcycloheptene, 1-methylcyclopentene, 2-ethyl-1 -hexene, 2,4,4- trimethyl-1-pentene, indene or any mixture thereof. More preferably, the chain transfer agent comprises diisobutylene (DIB). The chain transfer agent is preferably added to the reaction mixture in an amount of from 0.001 wt% to 1 wt%, based on weight of the isoolefin monomer in the reaction mixture. More preferably, the amount of chain transfer agent is in a range of from 0.005 wt% to 0.7 wt%. The isoolefin polymer can be subjected to a halogenation process in order to produce a halogenated branched isoolefin polymer. Halogenation preferably comprises bromination or chlorination. Halogenation agents useful for halogenating an isoolefin polymer may comprise elemental chlorine (Ch) or bromine (Br2) and/or organo-halide precursors thereto, for example dibromo-dimethyl hydantoin, tri-chloro isocyanuric acid (TCIA), n-bromosuccinimide, or the like. Preferably, the halogenation agent comprises or is bromine. The amount of halogenation during this procedure may be controlled so that the final polymer has a preferred amount of halogen. The specific mode of attaching the halogen to the polymer is not particularly restricted and those of skill in the art will recognize that modes other than those described above may be used while achieving the benefits of the invention. For additional details and alternative embodiments of solution phase halogenation processes, see, for example, Ullmann's Encyclopedia of Industrial Chemistry (Fifth, Completely Revised Edition, Volume A231 Editors Elvers, et al.) and/or "Rubber Technology" (Third Edition) by Maurice Morton, Chapter 10 (Van Nostrand Reinhold Company, 1987), particularly pp. 297-300, which are incorporated herein by reference.

The branched isoolefin polymer may be formulated into a compound. The compound comprises the branched isoolefin polymer and a filler. One or more fillers may be in the compound. The compound may be uncured or cured.

The filler may comprise a non-mineral filler, a mineral filler or mixtures thereof. The filler may be functionalized or unfunctionalized.

Non-mineral fillers include, for example, carbon blacks, rubber gels and mixtures thereof. Suitable carbon blacks are preferably prepared by lamp black, furnace black or gas black processes. Carbon blacks preferably have BET specific surface areas of 20 to 200 m.sup.2/g. Some specific examples of carbon blacks are SAF, ISAF, HAF, FEF and GPF carbon blacks. Rubber gels are preferably those based on polybutadiene, butadiene/styrene copolymers, butadiene/acrylonitrile copolymers or polychloroprene.

Mineral fillers include, for example, silica, silicates, clay, bentonite, vermiculite, nontronite, beidelite, volkonskoite, hectorite, saponite, laponite, sauconite, magadiite, kenyaite, ledikite, gypsum, alumina, talc, glass, metal oxides (e.g., titanium dioxide, zinc oxide, magnesium oxide, aluminum oxide), metal carbonates (e.g., magnesium carbonate, calcium carbonate, zinc carbonate), metal hydroxides (e.g., aluminum hydroxide, magnesium hydroxide) or mixtures thereof. Dried amorphous silica particles suitable for use as mineral fillers may have a mean agglomerate particle size in the range of from 1 to 100 microns, or 10 to 50 microns, or 10 to 25 microns. In one embodiment, less than 10 percent by volume of the agglomerate particles may be below 5 microns. In one embodiment, less than 10 percent by volume of the agglomerate particles may be over 50 microns in size. Suitable amorphous dried silica may have, for example, a BET surface area, measured in accordance with DIN (Deutsche Industrie Norm) 66131, of between 50 and 450 square meters per gram. DBP absorption, as measured in accordance with DIN 53601, may be between 150 and 400 grams per 100 grams of silica. A drying loss, as measured according to DIN ISO 787/11 , may be from 0 to 10 percent by weight.

High aspect ratio fillers useful in the present invention may include clays, talcs, micas, etc. with an aspect ratio of at least 1:3. The fillers may include acircular or nonisometric materials with a platy or needle-like structure. The aspect ratio is defined as the ratio of mean diameter of a circle of the same area as the face of the plate to the mean thickness of the plate. The aspect ratio for needle and fiber shaped fillers is the ratio of length to diameter. The high aspect ratio fillers may have an aspect ratio of at least 1:5, or at least 1:7, or in a range of 1:7 to 1:200. High aspect ratio fillers may have, for example, a mean particle size in the range of from 0.001 to 100 microns, or 0.005 to 50 microns, or 0.01 to 10 microns. Suitable high aspect ratio fillers may have a BET surface area, measured in accordance with DIN (Deutsche Industrie Norm) 66131, of between 5 and 200 square meters per gram. The high aspect ratio filler may comprise a nanoclay, such as, for example, an organically modified nanoclay. Examples of nanoclays include natural powdered smectite clays (e.g., sodium or calcium montmorillonite) or synthetic clays (e.g., hydrotalcite or laponite). In one embodiment, the high aspect filler may include organically modified montmorillonite nanoclays. The clays may be modified by substitution of the transition metal for an onium ion, as is known in the art, to provide surfactant functionality to the clay that aids in the dispersion of the clay within the generally hydrophobic polymer environment. In one embodiment, onium ions are phosphorus based (e.g., phosphonium ions) or nitrogen based (e.g., ammonium ions) and contain functional groups having from 2 to 20 carbon atoms. The clays may be provided, for example, in nanometer scale particle sizes, such as, less than 25 microns by volume. The particle size may be in a range of from 1 to 50 microns or 1 to 30 microns or 2 to 20 microns. In addition to silica, the nanoclays may also contain some fraction of alumina. For example, the nanoclays may contain from 0.1 to 10 wt% alumina, or 0.5 to 5 wt% alumina, or 1 to 3 wt% alumina, based on weight of the branched isoolefin polymer. The branched isoolefin polymer may be present in the compound in an amount of about 1-100 phr, or 1 to 90 phr or about 5-75 phr, or less than 50 phr, or about 1-50 phr, or about 1 phr to less than 50 phr, or about 10-50 phr, or about 5-30 phr, or about 15-30 phr. Fillers may be present in the compound in an amount of about 1-100 phr, or about 3- 80 phr, or about 5-60 phr, or about 5-30 phr, or about 5-15 phr.

The compound may contain further auxiliary products, such as reaction accelerators, vulcanizing accelerators, vulcanizing acceleration auxiliaries, antioxidants, foaming agents, anti-aging agents, heat stabilizers, light stabilizers, ozone stabilizers, processing aids, plasticizers, tackifiers, blowing agents, dyestuffs, pigments, waxes, extenders, organic acids, inhibitors, metal oxides, and activators such as triethanolamine, polyethylene glycol, hexanetriol, etc., which are known to the rubber industry. The aids are used in conventional amounts, which depend inter alia on the intended use. Conventional amounts are e.g., from 0.1 to 50 wt%, based on the weight of branched isoolefin polymer. For example, the compound furthermore may contain in the range of 0.1 to 20 phr of an organic fatty acid, such as an unsaturated fatty acid having one, two or more carbon double bonds in the molecule which more preferably includes 10 wt% or more of a conjugated diene acid having at least one conjugated carbon-carbon double bond in its molecule. For example, those fatty acids have in the range of from 8-22 carbon atoms, or for example, 12-18. Examples include stearic acid, palmitic acid and oleic acid and their calcium-, zinc-, magnesium-, potassium- and ammonium salts.

The compound may further contain other natural or synthetic rubbers such as ABR (butadiene/acrylic acid-Ci-C -alkylester-copolymers), CR (polychloroprene), IR (polyisoprene), SBR (styrene/butadiene-copolymers) with styrene contents in the range of 1 to 60 wt%, NBR (butadiene/acrylonitrile-copolymers with acrylonitrile contents of 5 to 60 wt%, HNBR (partially or totally hydrogenated NBR-rubber), FKM (fluoropolymers or fluororubbers), PIB (polyisobutylene), HR (butyl rubber), IMS (poly(isobutylene-co- paramethylstyrene)) and mixtures thereof.

The compound may be prepared by blending the branched isoolefin polymer and the filler, and optionally then curing the blend. The ingredients of the final compound can be mixed together in any known manner. Normally the mixing time does not exceed one hour and a time in the range from 2 to 30 minutes is usually adequate. Ingredients may be compounded together using conventional compounding techniques. Suitable compounding techniques include, for example, mixing the ingredients together using, for example, an internal mixer (e.g., a Banbury mixer), a miniature internal mixer (e.g., a Haake or Brabender mixer) or a two-roll mill mixer. An extruder also provides good mixing, and permits shorter mixing times. It is possible to carry out the mixing in two or more stages, and the mixing can be done in different apparatuses, for example one stage in an internal mixer and one stage in an extruder. For further information on compounding techniques, see Encyclopedia of Polymer Science and Engineering, Vol. 4, p. 66 et seq. (Compounding). Other techniques, as known to those of skill in the art, are further suitable for compounding.

The choice of curing system suitable for use is not particularly restricted and is within the purview of a person skilled in the art. In certain embodiments, the curing system may be sulphur-based, peroxide-based, resin-based or ultraviolet (UV) light- based.

A sulfur-based curing system may comprise: (i) a metal oxide, (ii) elemental sulfur and (iii) at least one sulfur-based accelerator. The use of metal oxides as a component in the sulphur curing system is well known in the art. A suitable metal oxide is zinc oxide, which may be used in the amount of from about 1 to about 10 phr. In another embodiment, the zinc oxide may be used in an amount of from about 2 to about 5 phr.

Elemental sulfur is typically used in amounts of from about 0.2 to about 2 phr. Suitable sulfur-based accelerators may be used in amounts of from about 0.5 to about 3 phr. Nonlimiting examples of useful sulfur-based accelerators include thiuram sulfides (e.g., tetramethyl thiuram disulfide (TMTD)), thiocarbamates (e.g., zinc dimethyl dithiocarbamate (ZDC)) and thiazyl or benzothiazyl compounds (e.g., mercaptobenzothiazyl disulfide (MBTS)).

Peroxide based curing systems may also be suitable. A peroxide-based curing system may comprises a peroxide curing agent, for example, dicumyl peroxide, di-tert- butyl peroxide, benzoyl peroxide, 2,2'-bis(tert.-butylperoxy diisopropylbenzene, benzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexyne-3, 2,5-dimethyl-2,5- di(benzoylperoxy)hexane, (2, 5-bis(tert-butylperoxy)-2, 5-dimethyl hexane and the like. A preferred peroxide curing agent comprises dicumyl peroxide. Peroxide curing agents may be used in an amount of about 0.2-15 phr, or about 1-6 phr, or about 4 phr. Peroxide curing co-agents may also be used. Suitable peroxide curing co-agents include, for example, triallyl isocyanurate (TAIC), N,N'-m-phenylene dimaleimide, triallyl cyanurate (TAC) or liquid polybutadiene. Peroxide curing co-agents may be used in amounts equivalent to those of the peroxide curing agent, or less.

The compound may be cured by resin cure system and, if required, an accelerator to activate the resin cure. Suitable resins include but are not limited to phenolic resins, alkylphenolic resins, alkylated phenols, halogenated alkyl phenolic resins and mixtures thereof.

In some cases, curing may be achieved by heating the compound at a suitable curing temperature in the presence of the curing system. The curing temperature may be about 80°C to about 250°C., or 100°C to about 200°C., or about 120°C to about 180°C.

The branched isoolefin polymers, halogenated branched isoolefin polymers and compounds thereof are useful in the production of articles of manufacture. Branched polymers produced by the process described herein have reduced cold flow and improved green strength, which are particularly beneficial for the production of tire parts (e.g., tire innerliners, tire inner tubes, tire sidewalls and tire treads), curing bladders, curing envelopes, seals, gaskets, adhesives, sealants, building and construction applications, chewing gum, food contact applications (e.g., conveyor belts, closures, etc.), pharmaceutical closures, medical devices (e.g., plungers, vacuum tube stoppers, etc.), tank linings, personal protective equipment (e.g., gloves, masks, clothing, etc.), hoses, thermoplastic vulcanizates (TPV), shoe soles, diaphragms in water contact applications, septa, vibration dampers, viscosity modifiers, and roofing materials.. Branched isoolefin polymers are also useful as tackifiers for greases and as a motor oil additive to provide suitable viscosity characteristics. Branched HR and IMS copolymers in particular also find use in vibration dampers. Branched PIB is in particular also added as a component with other polymers in other articles, generating a blended material.

The process and the branched isoolefin polymers, halogenated branched isoolefin polymers and rubber compounds thereof have one or more of the following advantages: ability to produce a branched polymer in one step that performs equally to a post-modified cross-linked isoolefin polymer; faster dissolution of the polyfarnesene in comparison to other branching agents; improved slurry stability during polymerization; higher mixer torque with similar creep; reduced mixing time when compounding; less processing oil required when compounding to produce uncured articles of the same processability but improved permeability; better filler dispersion with similar creep; higher green modulus with similar creep; similar raw polymer Mooney viscosity but lower compound Mooney viscosity; higher tan delta values across a frequency sweep; lower G’ values across a range of dynamic amplitudes; higher viscosity polymer produced with a small amount of branching agent within a given production process; maintaining molecular weight at higher polymerization temperatures; higher PDI but lower oligomer content; and, improved or maintained creep over aging. EXAMPLES

Test Methods :

Mooney viscosity was measured according to ASTM 1646.

Green strength was measured according to ASTM 6746.

Rheological measurements for van Gurp-Palmen plots were done in accordance with known methods as described in Van Gurp and Palmen. Rheol Bull, 67, 5 (1998); Trinkle and Fredrich. Rheol Acta, 40, 322 (2001); and, Trinkle. et al. Rheol Acta, 41, 103 (2002), the entire contents of all incorporated herein by reference. In short, rheological measurements were made with an Anton Paar MCR stress-controlled rheometer. All measurements were made under strain amplitudes within the linear viscoelastic limit, which was determined from strain sweep experiments.

Rheological measurements for creep were done in accordance with known methods as described in Plazek et al. Macromolecules, 25, 4920 (1992); and, Liu et al. J. Rheol., 57, 89 (2013), the entire contents of both incorporated herein by reference. In short, steady-shear creep measurements were made with an Anton Paar MCR stress- controlled rheometer. Creep testing was performed at 20°C with a constant applied stress. The yield point was identified as point at which the maximum stress is achieved.

Materials:

Isobutylene (IB) (99.5%) was purchased from Air Liquide. Methyl chloride (MeCI) (99.5%) was purchased from Praxair. Hexanes (a mixture of isomers, 98+%, anhydrous), isoprene (IP, 3-methyl-1, 3-butadiene), paramethylstyrene (pMS), aluminum chloride (AlCh), diethylaluminum chloride (DEAC, 1.0 M in hexanes and 100%), ethylaluminum dichloride (EADC, 1.0 M in hexanes), hydrogen chloride gas (99%), isopropyl alcohol and DIB (3 parts 2,4,4-trimethyl-1-pentene + 1 part 2,4,4-trimethyl-2-pentene) were purchased from Sigma-Aldrich. Isoprene was distilled over calcium hydride before use; paramethylstyrene was passed over an inhibitor removal column; hexanes, methyl chloride, aluminum chloride, DEAC, EADC and DIB were used as received. Polyfarnesene (Krasol F 3000) was obtained from Total Cray-Valley and used as received. Other polyfarnesenes were obtained from Kuraray (US) and Polymer Source (CA). Irganox™ 1076 was purchased from Cieba and used as received. Additional hexanes, ethanol and sodium hydroxide were purchased from VWR and used as received. Slurry polymerization reactions:

All manipulations for the slurry polymerization reactions were performed in an MBraun™ glovebox filled with nitrogen and equipped with liquid nitrogen-cooled pentane baths. The following general procedure for slurry polymerization was used to prepare butyl rubber and other isobutylene polymer samples in Examples 1-5.

A stock initiator solution of aluminum trichloride (AICI₃) is prepared by dissolving 0.3 g in 100 mL of methyl chloride at -30°C and stirring for 30 mins, which is then set aside for subsequent use.

A stock solution of polyfarnesene is prepared by dissolving 0.2 g in 100 mL of methyl chloride at -30°C, which is then set aside for subsequent use.

A cooling bath is cooled to -95°C. Isobutylene (10 mL if no other comonomer is present, otherwise 20 mL) and methyl chloride (180 mL) and a desired amount of branching agent are added to a stainless steel 600 mL reactor being cooled by the cooling bath. For HR polymers, isoprene (0.7 mL unless otherwise noted) was also added with the isobutylene. For IMS polymers, p-methylstyrene (2 mL) was also added with the isobutylene. A desired amount of chain transfer agent is also added, if desired.

An aliquot of the stock AICI₃ solution is then added once the reaction mixture reaches less than -90°C. The reaction is allowed to proceed for 5 minutes and then quenched with 1 mL of a 1 wt% NaOH in ethanol solution. The reactor is removed from the glovebox, hexane is added and the methyl chloride is allowed to evaporate overnight. The polymer is then coagulated from the hexane cement using ethanol, and dried at 60°C under vacuum.

Solution polymerization reactions:

All manipulations for the solution polymerization reactions were performed in an MBraun™ glovebox filled with nitrogen and equipped with liquid nitrogen-cooled pentane baths. The following general procedure for solution polymerization was used to prepare butyl rubber and other isobutylene polymer samples in Example 6.

In an Erlenmeyer flask, a catalyst solution was prepared by mixing approximately 1 part 1.0 M DEAC in hexanes, 1 part 1.0 M EADC in hexanes with 8 parts hexanes, generating a solution of ethylaluminum sesquichloride (EASC). The solution was stirred for approximately 5 minutes, after which point a small amount of deionized water is added dropwise (< 40 pL per 1 mL of DEAC/EADC). The solution was allowed to stir for approximately 15 minutes, after which point it was filtered through a 0.45 pm filter disc and collected into a new Erlenmeyer flask.

In a separate Erlenmeyer flask, a polyfarnesene solution of 0.1 g in 50 mL of hexane was prepared swirling the flask by hand to dissolve the liquid polymer. A pentane bath was cooled to -85 °C and a 600 mL stainless steel reactor was allowed to cool in the bath. 40 mL of hexanes, minus any hexane added with the polyfarnesene required, was added to the reactor, followed by 80 mL of liquid isobutylene. The reactor, equipped with an overhead stirrer, was stirred at approximately 400 rpm. At room temperature, 2.4 mL of isoprene or 2 mL of paramethylstyrene were added if required. Polymerization reactions were initiated using between 2 and 4 mL of the catalyst solution once the reactor temperature was below -80 °C.

Polymerizations were allowed to continue for 30 minutes or until the temperature rise exceeded 15°C, at which point 1-2 mL of a 1 wt% NaOH solution in ethanol was added to quench the reaction. The reactors were removed from the glovebox and hexanes (about 200 mL) and a 1 wt% Irganox™ 1076 solution in hexanes (1 mL) were added. After allowing to stand overnight, the polymers were coagulated by adding ethanol (about 500 mL) to the reactors. The polymers were dried at 60°C under vacuum. Polymers used in compounding studies were dried on the mill at 100°C prior to compounding.

Halogenation of butyl-type polymers:

Typical brominations were performed in a 300 mL ChemRxnHub™ jacketed lab reactor. Polymer cement was prepared overnight with stirring at 100 rpm by adding hexane (210 mL), 25 g of polymer, and 0.125 g of calcium stearate to the reactor. 30 minutes before brominations were to commence, stirring was increased to 350 rpm, water (87.5 mL) was added to the reactor, and the temperature control unit was set to 20°C. Bromination was commenced by adding 0.29 mL of liquid bromine to the reactor via a glass syringe. The reaction was allowed to proceed for 5 minutes at which point 10 mL of a 2.5 M sodium hydroxide solution was added to quench the reaction and HBr byproduct. Water washes were performed until aqueous extracts reached an approximate pH of 7. Irganox™ 1010 (0.0125 g), calcium stearate (0.650 g), and epoxidized soybean oil (0.325 g) were incorporated into the cement, after which the product was steam coagulated on the same day. All samples were dried in a 60°C vacuum oven and analyzed by ¹H NMR, GPC, and X-ray fluorescence. Polymers used in compounding studies were dried on the mill at 100°C prior to compounding. Typical chlorinations were performed as follows. 15 g of rubber was dissolved in hexane (150 mL) in a round bottom flask. Distilled water (100 mL) was added to the round bottom flask and the solution was agitated for approximately 5 minutes. While under agitation, NaOCI (commercial 5 wt% solution, 12 mL) and glacial acetic acid (4 mL) were added according to the desired halogenation level. The mixture was then stirred for 30 minutes, after which point acetone (130 mL) was added to coagulate the polymer. The polymer was dried using a Carver press heated to 100°C and analyzed for chlorine content by ¹H NMR. Polymers used in compounding studies were dried on the mill at 100°C prior to compounding.

Preparation ofSB-BIIR:

Styrene-butadiene-styrene copolymer (SBS) (KR01; Chevron Phillips Chemicals now produced by INEOS) was used as received. An SBS resin solution was prepared by dissolving about 4.4 g of resin in 100 mL MeCI in a 250 mL Erlenmeyer flask at -30°C with minor agitation for 30-60 minutes, unless otherwise stated. 180 mL of MeCI measured at -90°C, 20 mL of isobutylene measured at -90°C, 0.6 mL of isoprene measured at room temperature, 4.5 mL of the SBS resin solution (~0.2 g SBS resin) measured at -90°C, 6.0 mL of ~0.0225 M AICI₃ measured at -90°C were added in one shot.

The starbranched copolymer was then isolated as described above for slurry polymerizations and brominated as described above for bromination reactions.

Preparation of BIB-co-pMS\

A similar procedure to the slurry polymerization procedure described above. A stock solution of EADC was prepared, 20 wt% EADC in hexane. A stock solution of diluted HCI was prepared by mixing 1 mL of liquid HCI (by cooling the HCI cylinder in the cold pentane bath) with 14 mL methyl chloride to make 1/15 diluted HCI solution. Catalyst feed was prepared by mixing 8.8 mL of EADC stock solution and 7.02 mL of HCI stock solution in to 800 mL methyl chloride. Monomer feed mixture, 2200 mL, was prepared by mixing MeCI, IB, and pMS in the ratio of 85:13.5:1.5 by wt%, of which 400 mL was placed in a stainless steel reactor prior to the start of the polymerization.

The monomer feed, a 10 wt% pMS and 90 wt% IB feed in methyl chloride was stored at -95°C to -98°C in the cold bath during use. Catalyst solution (mixture of EADC and HCI) was prepared in methyl chloride and stored was stored at -95°C to -98°C in the cold bath for use. Polymerizations were performed semi-continuously by continual addition of monomer feed to the reactor. The reactions was quenched with about 10 ml of isopropyl alcohol. The polymer obtained was separated after evaporating the MeCI in a ventilated hood, and the precipitated polymer was removed from the reactor and collection pot. The polymer was dried in a vacuum oven at 40°C.

Bromination was carried out in a two-liter stirred glass reactor with nitrogen purge. The dried polymer prepared from the polymerization step was used for bromination reactions. 110 g of polymer was dissolved in 1200 mL dried hexane in the bromination reactor. The required amount of bromine needed (~3.5 g) to achieve the target was weighed in a beaker. The bromine was added slowly to the polymer solution with vigorous stirring. To initiate the bromination reaction, a light was placed over the reactor to shine on the reaction mixture. At end of the reaction, the bromination reaction was quenched by adding 1.5 M aqueous sodium hydroxide solution. The reaction mixture was washed four times with 500 mL portions of distilled water, stirring each washing vigorously for 15 minutes, settling, and removing the aqueous layer. Washing was repeated until the pH of the aqueous phase was about 7. The brominated polymer was isolated from the hexane by precipitation by pouring the mixture in to a beaker containing excess acetone. The polymer was separated and dried in a vacuum oven at 40°C.

Example 1 Branched HR using polyfarnesene branching agent

Comparison of polyfarnesene and SBS branching agents

The general polymerization procedure above was used to produce branched butyl rubbers (branched HR) using various amounts of polyfarnesene (Krasol™ F 3000) as follows: 5 mg, 10 mg, 20 mg, 30 mg, and 30 mg + 100 pL diisobutylene (DIB). The rheology of the branched butyl rubbers produced was studied and compared to the rheology of a butyl rubber Control prepared in the same way without branching agent and compared to the rheology of a starbranched bromobutyl rubber (SB-BIIR) prepared using about 1.4 wt% of a styrene-butadiene-styrene (SBS) resin (KR-01 Resin, INEOS) as a branching agent in the polymerization reaction.

Comparison of the starbranched bromobutyl rubber (SB-BIIR) with the butyl rubber polymers from the reactions containing various amounts of polyfarnesene are shown using a van Gurp-Palmen plot in Fig. 1, which demonstrate the differences in the level of long chain branching (LCB) and the number of short chains by looking at d at G* = 8,000 Pa and the d at G* = 300,000 Pa, respectively. It is evident from Fig. 1 that the level of branching is higher for all of the samples produced using polyfarnesene than for both the SB-BIIR and the Control. Further, the number of short chains is higher in the SB- BIIR than in the branched butyl rubbers produced using polyfarnesene, except for the butyl rubber sample that was prepared using both the polyfarnesene branching agent and DIB chain transfer agent. Rheological analysis using the van Gurp-Palmen plot allowed for the use of design of experiments (DoE) to determine recipes of polyfarnesene (Krasol™ F 3000) and chain transfer agent (DIB) that are required to generate a branched butyl rubber with a similar level of chain branching, a similar number of short chains and a similar modulus to SB-BIIR. The recipes of the branched butyl rubbers produced using polyfarnesene (PF- HR Solution 1 and PF-IIR Solution 2) as well as the butyl rubber Control and SB-BIIR are shown in Table 2. PF-IIR Solution 1 contains 20 mg of polyfarnesene added to the polymerization along with 70 pl_ of diisobutylene (DIB) as a chain transfer agent, while PF-IIR Solution 2 contains 11 mg of polyfarnesene and 40 mI_ of DIB.

The rheological analysis of PF-IIR Solution 1 and PF-IIR Solution 2 and the SB- BIIR material is shown in Fig. 2. It is evident from Fig. 2 and Table 2 that far less polyfarnesene than SBS resin is needed to produce branched butyl rubber having similar rheological characteristics.

Table 2

Creep compliance and green strength

The branched butyl rubber products produced from use of a polyfarnesene branching agent (PF-IIR Solution 1 and PF-IIR Solution 2) were both analyzed as raw polymers. The raw polymer properties demonstrated that the branched butyl rubber products have improved creep compliance (Fig. 3) and higher peak green strength (Fig. 4) in comparison to commercial polymers ARLANXEO regular butyl polymers RB100 and

RB402 with similar Mooney viscosity (see Table 3). Table 3

Halogenation of HR

The branched butyl rubber products produced from use of a polyfarnesene branching agent (PF-IIR Solution 1 and PF-IIR Solution 2) were halogenated on a small scale to produce halogenated versions of each product. The branched bromobutyl products (PF-BIIR Solution 1 and PF-BIIR Solution 2) are alternatives to starbranched bromobutyl rubbers. The raw polymer properties of the brominated butyl rubbers in comparison to a commercial ARLANXEO regular bromobutyl polymer (BB2030) and a starbranched bromobutyl rubber are shown in Table 4.

Table 4

Example 2 Branched PIB using polyfarnesene branching agent

The general polymerization procedure above was used to produce branched polyisobutylene polymers using polyfarnesene (Krasol™ F 3000) together with diisobutylene (DIB) chain transfer agent. The rheology of the branched polyisobutylene polymers produced was studied and compared to the rheology of a commercial PIB Control prepared without branching agent and compared to the rheology of branched poly(isobutylene-co-isoprene) (butyl rubbers: PF-IIR Solution 1 and PF-IIR Solution 2) also produced using Krasol™ F 3000 as a branching agent. The polymerization recipes used are shown in Table 5. Results of rheological studies are shown using a van Gurp-Palmen plot in Fig. 5, which demonstrate the differences in the level of long chain branching (LCB) and the number of short chains by looking at d at G* = 8,000 Pa and the d at G* = 300,000 Pa, respectively. When polyfarnesene is added to polyisobutylene polymerizations, all of the PIB polymers produced are more branched, with fewer short chains than highly branched butyl rubber polymers (PF-IIR Solution 1 and PF-IIR Solution 2) also produced using polyfarnesene, as seen in Fig. 5.

It was found that the addition of greater than 50 mg of Krasol™ F 3000 per 10 mL (7.05 g) of isobutylene resulted in minimal or no conversion in the polymerization.

Table 5

Example 3 Branched IMS using polyfarnesene branching agent

The general polymerization procedure above was used to produce branched poly(isobutylene-co-paramethylstyrene) using polyfarnesene (Krasol™ F 3000) together with diisobutylene (DIB) chain transfer agent. The rheology of the branched isobutylene- co-paramethylstyrene polymers produced was studied and compared to the rheology of various other polymers. Polymerization recipes are shown in Table 6.

Table 6

Results of rheological studies are shown using a van Gurp-Palmen plot in Fig. 6, which demonstrate the differences in the level of long chain branching (LCB) and the number of short chains by looking at d at G* = 8,000 Pa and the d at G* = 300,000 Pa, respectively. The following matches the entries in Table 6 to the legend in Fig. 6

P1 = Butyl Glovebox Control (MR control) P2 = Butyl + Polyfarnesene + DIB (PF-IIR Solution 1)

P3 = IB-co-pMS (IMS control) P4 = Butyl + DIB (MR control with DIB)

P5 = IB-co-pMS + Polyfarmesene + DIB (branched IMS) P6 = IB-co-pMS + DIB (IMS control with DIB) P7 = BIB-co-pMS (brominated IMS control)

P8 = SB-BIIR (star branched BUR prepared with SBS)

As seen in Fig. 6, polyfarnesene is also an effective branching agent for isobutylene-co-paramethylstyrene polymerizations, giving a branched version of IMS, which is the precursor to brominated IMS (BIB-co-pMS). BIB-co-pMS has about 5 mol% paramethylstyrene, about 0.85 mol% brominated paramethylstyrene units and a Mooney viscosity of 35 (MU 1+8, 125°C). BIB-co-pMS is a very linear polymer in comparison to HR, as there are no mechanisms by which branching can be introduced during polymerization. This leads to poor processability of the BIB-co-pMS during mixing, and has limited its widespread adoption in the industry. When polyfarnesene is added, along with DIB to an isobutylene/paramethylstyrene polymerization, a branched polymer, PF- IMS, can be generated with a similar amount of branching to SB-BIIR (Fig. 6). The ability to introduce short chains into IMS while maintaining a higher Mooney viscosity may give a polymer than behaves more like HR, but maintains the cleanliness and improved permeability of BIB-co-pMS. The addition of 120 mg of polyfarnesene was well tolerated by the isobutylene/paramethylstyrene polymerization but began to poison the reaction above 140 mg per 20 mL of isobutylene.

Example 4 Different polyfarnesenes

Branched butyl rubber samples were produced in accordance with the general polymerization reaction described above using 20 mg of various polyfarnesenes having various molecular weights and enchainment. The samples were produced using the polyfarnesenes listed in Table 1.

Results of rheological studies are shown using a van Gurp-Palmen plot in Fig. 7, which demonstrate the differences in the level of long chain branching (LCB) and the number of short chains by looking at d at G* = 8,000 Pa and the d at G* = 300,000 Pa, respectively. Results on polyisobutylene (PIB), a related isoolefin polymer that is highly linear, produced without a branching agent are included in Fig. 7 for further comparison. It is evident from Fig. 7 that the level of branching is higher for all of the samples produced using a polyfarnesene than for the Control butyl rubbers and much higher than in the highly linear polyisobutylene. Thus, polyfarnesenes across a large molecular weight range and with a variety of enchainment types are useful as branching agents.

Example 5 Different polyterpenes

Other cyclic polyterpenes were screened for their ability to branch butyl rubber during polymerization. Poly-a-pinene, poly-b-pinene, poly-d-limonene, mixed polypinene, styrenated poly-a-pinene and terpene phenolic resins were all screened for branching ability for butyl rubber and it was shown that with the examples that were used, there was no difference in rheology between control experiments and experiments with 100 mg of cyclic polyterpene added. Fig. 8 shows the results for poly-a-pinene and poly-d-limonene (M_n <1000 g/mol and used in an amount of 100 mg) in comparison to branched butyl rubber produced using a polyfarnesene branching agent (Krasol™ F 3000 used in an amount of 20 mg) and butyl rubber controls that were not produced in the presence of a branching agent. Results on polyisobutylene (PIB), a related isoolefin polymer that is highly linear, produced without a branching agent are included in Fig. 8 for further comparison. It is evident from Fig. 8 that the poly-a-pinene and poly-d-limonene did not act as branching agents as the level of branching of the butyl rubber polymers produced is little different from the Controls. Example 6 - Solution polymerization

The addition of polyfarnesene to solution polymerizations of isobutylene-co- isoprene (HR), isobutylene-co-paramethylstyrene (IMS) and polyisobutylene (PIB) in hexane have also been successfully performed. MR, IMS, PIB and the branched versions with polyfarnesene were prepared according to the recipes in Table 7 (MR), Table 8 (IMS) and Table 9 (PIB), and analyzed using MCR.

Table 7

Table 8

Table 9

As seen in Fig. 9, branching is observed for each polymer type when polyfarnesene is introduced into the monomer feed. Although it appears as though the PF-IMS polymer has less branching than the parent IMS polymer, this is not the case, as the IMS polymer appears to have a broad molecular weight distribution, broadening the relaxation of the polymer.

Example 7 - Branched PIB using polyfarnesene branching agent

Polyfarnesene can be used to generate branched polyisobutylene polymers. When polyfarnesene is added to polyisobutylene polymerizations in the amounts outlined in Table 10, all of the polymers produced are branched, with fewer short chains than the N50 PIB production sample, as per rheological testing using a modular compact rheometer (MCR) shown in a van Gurp-Palmen plot in Fig. 10. It was found that the addition of greater than 50 mg of Krasol F 3000 (25 mL of a 2 mg/ml_ solution) per 10 mL of isobutylene resulted in some poisoning of the polymerization.

Table 10

Example 8 Different polyfarnesenes

The range of farnesene polymers that can be used to generate branched polyisobutylenes is quite wide. Along with Krasol F 3000 that has a molecular weight of 3000 g/mol (number of farnesene units = 14), polyfarnesenes with as few as 6 units and as many as 636 units (Table 11) have been used to generate branched polyisobutylenes, shown in Table 12 and Fig. 11. Farnesene copolymers with butadiene also show effectiveness in producing branched polymers.

Table 11

Table 12

30

RECTIFIED SHEET (RULE 91.1) Example 9 - Hydrogenated polyfarnesene

To confirm that the effect of polyfarnesene is due to the presence of the unsaturation in the polymer, hydrogenated polyfarnesene, commercially available from Total-Cray Valley as Krasol F 3100, was screened. 50 mg of Krasol F 3100 was added to polymerizations with isobutylene (Table 13) and the resultant polymer was analyzed using a van Gurp-Palmen plot, shown in Fig. 12. This polymer was compared to examples containing 10 mg of Krasol F 3000, and was found to be linear, with a similar curve profile to the PIB N50 control.

Table 13

Example 10- Solution polymerization

The addition of polyfarnesene to solution polymerizations PIB in hexane were also successfully performed. PIB and the analogous version with polyfarnesene was prepared (Table 14) and analyzed using an MCR. These data are shown in Fig. 13. Branching is observed when polyfarnesene is introduced into the monomer feed.

Table 14

Example 11 - Characterization of PF-PIB

To demonstrate the presence of polyfarnesene in the PF-PIB samples and to confirm it is chemically bound to the polymer, beyond the rheological changes, ¹H NMR spectroscopy, pyrolysis-GCMS and GPC methods were used. As there is no unsaturation in polyisobutylene, the ¹H NMR spectrum of PIB displays no signals between approximately 2.5 and 6.5 ppm. When polyfarnesene is added as a branching agent to a PIB polymerization, the resultant polymer has several signals in this region corresponding to polyfarnesene, shown in Fig. 14.

Pyrolysis-GCMS also demonstrated that polyfarnesene was chemically bound to the PIB polymer chains and was not simply behaving as an additive causing alternative rheological behaviour. A sample of PF-PIB was purified by dissolving in hexane and coagulating with acetone three times to ensure that any residual, unbound polyfarnesene was removed from the polymer matrix. An overlay of pyrolysis-GCMS chromatograms, shown in Fig. 15, demonstrate a signal at a retention time of approximately 15.1 minutes that is present in a sample of pure polyfarnesene (middle, light grey) and PF-PIB (top, black), but not present in a control PIB N50 production sample (bottom, grey). The pyrolysis-GCMS was performed on a CDS Analytical Pyroprobe 5250T coupled to an Agilent 7890B GC with a 5977B MSD. 100 ug of sample was used and pyrolyzed at 500°C for 15 s. The sample was then run through an HP-5MS Ul column (30 m x 0.25 mm x 1 urn) using helium as the carrier gas, at a flow of 0.8 mL/min, with an inlet temperature of 250°C, and an initial column temperature of 50°C (held for 2 mins), followed by a ramp rate of 20°C per minute to 280°C, held for 10 min.

GPC was also used to analyzed the PF-PIB polymers prepared. A sample solution with 0.5 mg/ml_ in THF was prepared and analyzed using a Waters Alliance e2695 Separations module equipped with a Water 2414 Differential Refractometer. THF was used as the eluent at a flow rate of 0.8 mL/min at 35°C and passed through three Agilent Technologies PLgel 10 urn MIXED-B LS 300x7.5 mm columns. K and alpha values of 0.000200 and 0.670, respectively, were used for molecular weight calculations, based on polystyrene standards. Fig. 16 demonstrates a chromatogram of a N100 PIB production sample and a PF-PIB sample with similar creep behaviour. The MP of the PF-PIB sample has shifted to longer retention times (lower molecular weight) as shown by the chromatogram in Fig. 16, due to the increased number of shorter polymer chains. In addition, a significant high molecular weight shoulder is shown in the chromatogram, corresponding to the branched fraction of the polymer. Example 12- Scale up using design of experiments for recipe determination

Several polyfarnesene-containing PIB recipes were developed using design of experiments (DoE), utilizing creep compliance by MCR and molecular weight data as the key responses. This allowed for creep to be minimized, while also minimizing molecular weight, with various importance levels being assigned to each factor, depending on the performance of the rubber being targeted. Van Gurp-Palmen plots were not used for this DoE, as it was deemed to be more important to tune to the final polymer properties that would be most beneficial for the applications of this polymer. As high molecular weight PIB that is produced by ARLANXEO is primarily used in adhesives, sealants and sheeting, creep compliance was the logical property to examine.

The normal PIB recipe was used as a foundation for the DoE, where half of the isobutylene and half the initiator loading of the PF-IIR recipe was used (10 mL and 2.5 mL, respectively). A wider range of polyfarnesene loading was used due to the highly linear nature of the PIB polymer and the high activity of the polymerization. 2.5 to 23 mL of a 0.2 g / mL solution of Krasol F 3000 was used in the DoE, as well as a range of 7.6 to 92.5 uL of DIB. GPC data and creep data at 100°C were collected and analyzed by Design Expert 11 software. Three different recipes were determined by altering the priority level of the following responses: maximizing yield, minimizing Mn, Mw and Mz, while maximizing zero shear viscosity (inverse of the slope of the creep curve) and minimizing creep compliance (the end point after 7000 s). The three recipes obtained were 38 mg polyfarnesene, 23 uL DIB; 22 mg polyfarnesene, 50 uL DIB; and 30 mg polyfarnesene, 43 uL DIB. The recipes were scaled up and analyzed for their creep behaviour. They were compared to commercial production samples of N50, N80, N100 and N150.

Creep compliance and green strength

Overall, it was observed that all glovebox produced PF-PIB recipes demonstrated less creep, shown in Fig. 17, than the linear commercial samples, with comparable or lower Mn and Mp values (Table 15). Mw was higher in some cases than the grade that was being targeted; this is due to the branching being introduced by the polyfarnesene, increasing primarily the weight average molecular weight. The three recipes can be compared as such. PF-PIB 1, with 38 mg PF and 23 uL DIB, has a better zero shear viscosity with a roughly equivalent creep compliance to N150. The lower slope (inverse of zero shear viscosity) indicates that over longer time, this material will creep less. The reason for the slightly increased creep compliance at 7000 s is likely due to the higher number of short chains which cause an initially high slope in the first portion of the test. This also suggests that the material will be more processable than N150 but have comparable creep performance over time. The molecular weight data of PF-PIB 1 demonstrates a much lower Mn and Mw, which are roughly 1 million g/mol less and approximately half the values for N150, respectively.

PF-PIB 2, with 22 mg PF and 50 uL DIB, is a more comparable material to N50, with comparable Mn and slightly higher Mp, but with much improved zero shear viscosity and creep compliance, both by an order of magnitude. PF-PIB 2 has a better zero shear viscosity and similar creep compliance to N80 at 7000 s, again with the benefit of a lower overall molecular weight than N80. Similarly, PF-PIB 3, with 30 mg PF and 43 uL DIB, behaves similarly to N100 in terms of zero shear viscosity and creep compliance, but having a much lower overall molecular weight, especially in Mn, giving rise to the expected improvements in processability.

Table 15

A second set of PF-PIB samples were scale up for further analyses. The properties of these samples are shown in Table 16. A portion of these samples were aged in a hot air oven at 60°C for 161 days, simulating 5 years at ambient conditions. The samples were analyzed by GPC and creep compliance was measured using MCR at various times. Overall, the aged behaviour of the PF-PIB was improved in comparison to production samples of PIB. After 2 years, the PF-PIB samples experienced either no change, or a slight improvement in creep compliance, whereas linear commercial PIB samples demonstrated worse creep behaviour after two years, as shown in Fig. 18. As poorer performance can be attributed to degradation of the polymer, the results suggest that there is another process at play in the PF-PIB samples, preventing the loss of performance and improving the creep compliance overtime.

Table 16

Example 13- Preparation of a B200 analogue using polyfarnesene

A set of glovebox experiments were run to determine whether the introduction of branching through polyfarnesene could increase the viscosity of a polyisobutylene to a sufficient point to behave like a grade of PIB with a higher molecular weight. B200 is a commercial grade of PIB previously produced using a different polymerization process that has a higher molecular weight and higher viscosity than the current N150 grade, which is the upper limit of the current production process in terms of molecular weight. As shown in Fig. 19, which is a plot of viscosity vs shear rate amplitude measured at 200°C, at a shear rate of 0.05 s^_1, B200 and N150 have a different viscosity, with B200 being higher. Similarly, if comparing Exp 12 to Exp 13, the introduction of a small amount of polyfarnesene in Exp 13 has increased the viscosity of this polymer over the control. This would suggest that in a process that is limited to a given molecular weight (i.e., N150), polyfarnesene could be used in very small amounts to generate a product that has a higher viscosity than can normally be achieved, with a lower molecular weight (Table 17).

Table 17

Example 14- White filled compound of PF-PIB

PF-PIB materials were compounded into a white-filled window seals application, the formulation for which is shown in Table 18 and filled properties were measured, shown in Table 19. PF-PIB polymers with similar creep to commercial polymers demonstrated higher mixer torque, better filler dispersion, better processing and higher green modulus, as shown in Fig. 20 to Fig. 23.

Table 18

Table 19

Example 15- Black filled compound of PF-PIB

Similar results were observed with PF-PIB in a black filled sheeting compound, the formulation for which is shown in Table 20 and the filled compound properties are shown in Table 21. Again, PF-PIB polymers with similar creep to commercial polymers demonstrated higher mixer torque, better filler dispersion, better processing and higher green modulus, as shown in Fig. 24 to Fig. 27.

Table 20

Table 21

Fig. 28 and Fig. 29 show aged tensile data for a black sheeting compound with production PIB samples and PF-PIB. Overall, the results demonstrate that aged production PIB samples harden after hot air aging at 60°C, whereas PF-PIB samples with lower PF loadings soften after aging (with the exception of the PF-PIB with creep similar to N150). This would be advantageous for roofing applications, as a material that softens over time will maintain flexibility and avoid cracking. It could also improve performance at edges and areas of high curvature.

The novel features will become apparent to those of skill in the art upon examination of the description. It should be understood, however, that the scope of the claims should not be limited by the embodiments, but should be given the broadest interpretation consistent with the wording of the claims and the specification as a whole.

Claims

Claims:

1. A process for producing a branched polyisobutylene polymer, the process comprising polymerizing isobutylene monomer in a reaction mixture in presence of a branching agent, the branching agent comprising a polyfarnesene having 5 or more farnesene units.

2. The process of claim 1, wherein the polyfarnesene comprises from 5 to 640 farnesene units.

3. The process of claim 1, wherein the polyfarnesene comprises from 5 to 425 farnesene units.

4. The process of any one of claims 1 to 3, wherein the polyfarnesene is a homopolymer.

5. The process of claim 4, wherein the polyfarnesene homopolymer has a number average molecular weight (M_n) in a range of 1,000-130,000 g/mol.

6. The process of claim 4, wherein the polyfarnesene homopolymer has a number average molecular weight (M_n) in a range of 1,000-85,000 g/mol.

7. The process of any one of claims 1 to 3, wherein the polyfarnesene is a copolymer comprising at least one comonomer, the at least one comonomer comprising a conjugated diene or a styrene.

8. The process of claim 7, wherein the at least one comonomer comprises isoprene, 1,3-butadiene, piperylene, styrene, a-methylstyrene, paramethylstyrene, ocimene or myrcene.

9. The process of claim 7 or claim 8, wherein the at least one comonomer is present in the polyfarnesene copolymer in an amount in a range of 1-75 mol%.

10. The process of any one of claims 1 to 9, wherein the polyfarnesene is derived from farnesene comprising at least 95 mol% of trans-p-farnesene.

11. The process of any one of claims 1 to 10, wherein the branching agent is present in an amount of 0.01-2 wt% based on weight of the isobutylene in the reaction mixture.

12. The process of any one of claims 1 to 11, wherein the branching agent is introduced into the reaction mixture as a solution in an organic solvent.

13. The process of any one of claims 1 to 12, further comprising including a chain transfer agent in the reaction mixture.

14. The process of claim 13, wherein the chain transfer agent comprises diisobutylene (DIB).

15. The process of any one of claims 1 to 14, wherein the reaction mixture further comprises an organic diluent and an initiator system.

16. The process of claim 15, wherein the diluent comprises methyl chloride.

17. The process of claim 15, wherein the diluent comprises an alkane or cycloalkane.

18. The process of any one of claims 15 to 17, wherein the initiator system comprises a Lewis acid and a proton source.

19. A branched polyisobutylene polymer produced by the process of any one of claims 1 to 18.

20. A branched polyisoolefin polymer comprising isoolefin units and farnesene units.

21. The polymer of claim 20, wherein the isoolefin units are isobutylene units.

22. An article of manufacture produced from the polymer of any one of claims 18 to 21

23. The article of claim 22, which is a seal, a gasket, an adhesive, chewing gum, roofing material or a viscosity modifier.

24. Use of a polyfarnesene having 5 or more farnesene units as a branching agent for producing a branched polyisobutylene polymer.