BRANCHED BUTYL RUBBER POLYMERS

Cross-reference to Related Applications

This application claims priority to European patent application 21186984 filed July 21, 2021 and European patent application 21188260 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 (MR), 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 MR 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 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. 11 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. 10.

Fig. 12 depicts a van Gurp-Palmen plot of comparative runs with different polyfarnesene polymers with varying molecular weight and enchainment as branching agents for butyl rubber.

Fig. 13 depicts a van Gurp-Palmen plot of comparative runs with different polyfarnesene and polyfarnesene-co-butadiene polymers as branching agents for butyl rubber.

Fig. 14 depicts a van Gurp-Palmen plot of comparative runs of control, polyfarnesene and hydrogenated polyfarnesene as branching agents for butyl rubber.

Fig. 15 depicts a van Gurp-Palmen plot of glovebox controls, polyfarnesene, poly- a-pinene and poly-d-limonene as branching agents in butyl rubber.

Fig. 16 depicts a van-Gurp-Palmen plot of butyl rubber produced using a solution process. Fig. 17 depicts a ¹ H NMR spectrum of lab-produced butyl rubber (bottom) and lab- produced PF-IIR with 0.14 wt% polyfarnesene (top).

Fig. 18 depicts a pyrolysis-GCMS chromatogram of lab-produced butyl rubber (black), PF-IIR (grey) and polyfarnesene (dark grey).

Fig. 19 depicts a GPC chromatogram of control glovebox butyl rubber, and butyl rubbers produced in the glovebox using various amounts of polyfarnesene and diisobutylene.

Fig. 20 depicts a creep compliance versus time plot of lab-produced polyfarnesene-butyl rubber and commercial ARL RB100, RB402 and RB301 at 100°C.

Fig. 21 depicts a stress-strain plot of glovebox-produced polyfarnesene-butyl recipes and commercial polymers RB100 and RB402.

Fig. 22 depicts a creep compliance versus time plot of PF-IIR samples, aged at 50°C for the specified number of days.

Fig. 23 depicts highly branched PF-IIR comparable to Kalar grades. Fig. 24 depicts highly branched HR grades having improved creep compared to Kalar grades.

Fig. 25 depicts a cure curve generated using a moving die rheometer (MDR) at 1.7 Hz, 1 ° arc and 180°C of inner tube compounds, showing the cure rate and state of the regular butyl rubbers tested.

Fig. 26 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured inner tube compounds with regular butyl rubbers, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 27 depicts a tan delta (frequency sweep at 100 °C) plot of uncured inner tube compounds with regular butyl rubbers, showing improved processability with higher tan delta.

Fig. 28 depicts a mixer torque curve of large head uncured curing bladder compound.

Fig. 29 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 180°C of curing bladder compounds, showing the cure rate and state of the regular butyl rubbers tested.

Fig. 30 depicts a tan delta (frequency sweep at 100 °C) plot of uncured curing bladder compounds with regular butyl rubbers, showing improved processability with higher tan delta. Fig. 31 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured curing bladder compounds with regular butyl rubbers, showing improving no improvement in filler dispersion with equivalent G’ at 0.06 % dynamic amplitude.

Fig. 32 depicts a stress-extension plot of uncured curing bladder compounds with regular butyl rubber using the T2000 instrument. Fig. 33 depicts a stress-strain plot of cured curing bladder compounds demonstrating the tensile strength at break of regular butyl rubbers tested.

Fig. 34 depicts a mixer torque curve of highly filled black compound.

Fig. 35 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 160°C of highly filled black compounds, showing the cure rate and state of the regular butyl rubbers tested. Fig. 36 depicts a tan delta (frequency sweep at 100 °C) plot of uncured highly filled black compounds with regular butyl rubbers, showing improved processability with higher tan delta.

Fig. 37 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured highly filled black compounds with regular butyl rubbers, showing improved dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 38 depicts a G’ plot of cured strain sweep of highly filled black compounds with regular butyl, showing improved dispersion with lower G’ at low dynamic strain.

Fig. 39 depicts a stress-extension plot of uncured highly filled black compounds with regular butyl rubber using the T2000 instrument.

Fig. 40 depicts a stress-strain plot of cured highly filled black compounds demonstrating the higher modulus with PF-IIR vs. regular butyl rubbers tested.

Fig. 41 depicts a mixer torque curve of medical white filled compound.

Fig. 42 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 180°C of medical white filled compounds, showing the cure rate and state of the regular butyl rubbers tested.

Fig. 43 depicts a tan delta (frequency sweep at 100 °C) plot of uncured medical white filled compounds with regular butyl rubbers, showing improved processability with higher tan delta.

Fig. 44 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured medical white filled compounds with regular butyl rubbers, showing improved dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 45 depicts a stress-extension plot of uncured medical white filled compounds with regular butyl rubber using the T2000 instrument.

Fig. 46 depicts a stress-strain plot of cured medical white filled compounds demonstrating the higher modulus with PF-IIR vs. regular butyl rubbers tested.

Fig. 47 depicts a van Gurp-Palmen plot of lab chlorobutyl control and PF-CIIR.

Fig. 48 depicts a creep compliance at 100°C versus time plot of lab prepared PF- CIIR and lab prepared CNR rubber samples. Fig. 49 depicts a stress-strain plot of lab prepared PF-CIIR and lab prepared CNR.

Fig. 50 depicts a mixer torque curve of large head uncured innerliner compound.

Fig. 51 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured innerliner compounds with chlorobutyl rubbers, showing similar filler dispersion by G’ at 0.06 % dynamic amplitude.

Fig. 52 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 160°C of innerliner compounds, showing the cure rate and state of the chlorobutyl rubbers tested.

Fig. 53 depicts a tan delta (frequency sweep at 100 °C) plot of uncured innerliner compounds with chlorobutyl rubbers, showing improved processability with higher tan delta at a frequency of 25 Hz.

Fig. 54 depicts a stress-extension plot of uncured innerliner compounds with chlorobutyl rubber using the Instron instrument.

Fig. 55 depicts a stress-extension plot of cured innerliner compounds with chlorobutyl rubber.

Fig. 56 depicts a mixer torque curve of small head uncured pharmaceutical compounds.

Fig. 57 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 170°C of pharmaceutical compounds, showing the cure rate and state of the chlorobutyl rubbers tested.

Fig. 58 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured pharmaceutical compounds with chlorobutyl rubbers, showing similar filler dispersion at lower G’ at 0.06 % dynamic amplitude.

Fig. 59 depicts a tan delta (frequency sweep at 100 °C) plot of uncured pharmaceutical compounds with chlorobutyl rubbers, showing improved processability with higher tan delta at a frequency of 25 Hz.

Fig. 60 depicts a stress-extension plot of combined uncured pharmaceutical compounds with chlorobutyl rubber using the Instron instrument. Fig. 61 depicts a stress-extension plot of cured pharmaceutical compounds with chlorobutyl rubber.

Fig. 62 depicts compression set and permeability of cured pharmaceutical compounds with chlorobutyl rubber. Fig. 63 depicts a van Gurp-Palmen plot of lab BUR control vs. PF-BIIR.

Fig. 64 depicts a creep compliance at 100°C versus time plot of lab prepared PF- BIIR, lab prepared BUR, BB2030 and BBX2 rubber samples.

Fig. 65 depicts a stress-strain plot of lab prepared PF-BIIR, lab prepared BUR, BB2030 and BBX2. Fig. 66 depicts a mixer torque curve of large head uncured innerliner compound.

Fig. 67 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 160°C of innerliner compounds, showing the cure rate and state of the bromobutyl rubbers tested.

Fig. 68 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 69 depicts a tan delta (frequency sweep at 100 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing improved processability with higher tan delta.

Fig. 70 depicts a stress-extension plot of uncured innerliner compounds with bromobutyl rubber using the T2000 tensile instrument.

Fig. 71 depicts a stress-extension plot of uncured innerliner compounds with bromobutyl rubber using the Instron instrument.

Fig. 72 depicts a mixer torque curve of large head uncured innerliner compound.

Fig. 73 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 160°C of innerliner compounds, showing the cure rate and state of the bromobutyl rubbers tested. Fig. 74 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing similar filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 75 depicts a tan delta (frequency sweep at 100 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing improved processability with higher tan delta at a frequency of 25 Hz.

Fig. 76 depicts a stress-extension plot of uncured innerliner compounds with bromobutyl rubber using the T2000 tensile instrument. Includes comparison of previous results. Fig. 77 depicts a stress-extension plot of cured innerliner compounds with bromobutyl rubber using the T2000 tensile instrument.

Fig. 78 depicts a mixer torque curve of large head uncured innerliner compound.

Fig. 79 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 160°C of innerliner compounds, showing the cure rate and state of the bromobutyl rubbers tested.

Fig. 80 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 81 depicts a tan delta (frequency sweep at 100 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing improved processability with higher tan delta.

Fig. 82 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude. Fig. 83 depicts a tan delta (frequency sweep at 100 °C) plot of uncured innerliner compounds with bromobutyl rubbers, showing improved processability with higher tan delta.

Fig. 84 depicts a stress-extension plot of uncured innerliner compounds with bromobutyl rubber using the Instron instrument. Fig. 85 depicts 0 ₂ permeability of cured innerliner compounds with bromobutyl rubber using the Mocon instrument at 40 °C.

Fig. 86 depicts a mixer torque curve of two small head uncured pharmaceutical compounds. Fig. 87 depicts a cure curve generated using an MDR at 1.7 Hz, 1° arc and 170°C of pharmaceutical compounds, showing the cure rate and state of the bromobutyl rubbers tested.

Fig. 88 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured pharmaceutical compounds (day 1 samples) with bromobutyl rubbers, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 89 depicts a Payne Effect (strain sweep at 60 °C) plot of uncured pharmaceutical compounds (day 2 samples) with bromobutyl rubbers, showing improving filler dispersion with lower G’ at 0.06 % dynamic amplitude.

Fig. 90 depicts a tan delta (frequency sweep at 100 °C) plot of uncured pharmaceutical compounds with bromobutyl rubbers, showing improved processability with higher tan delta.

Fig. 91 depicts a stress-extension plot of combined uncured pharmaceutical compounds with bromobutyl rubber using the T2000 tensile instrument.

Fig. 92 depicts a stress-extension plot of cured pharmaceutical compounds with bromobutyl rubber of Day 1 samples.

Fig. 93 depicts a stress-extension plot of cured pharmaceutical compounds with bromobutyl rubber of Day 2 samples.

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-C ₄ 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 (AICI ₃ ). 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 (Et ₂ AICI or DEAC), ethyl aluminum sesquichloride (Eί _{1 5} AIOI _{1 5} or EASC), ethyl aluminum dichloride (EtAIC or EADC), diethyl aluminum bromide (Et ₂ AIBr or DEAB), ethyl aluminum sesquibromide (Et _t sAIBn s or EASB) and ethyl aluminum dibromide (EtAIBr ₂ 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 (H ₂ 0), 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

16

RECTIFIED SHEET (RULE 91.1)

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 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.

17

RECTIFIED SHEET (RULE 91.1) 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-CrC ₄ -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 (AICI3), 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 (AICI ₃ ) 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 MR 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 AICI ₃ 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 ¹ H 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 ¹ H NMR. Polymers used in compounding studies were dried on the mill at 100°C prior to compounding.

Preparation of SB-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 AICI ₃ 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 UR 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 mI_ 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 (HR 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 BIIR 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 HR using polyfarnesene branching agent

The addition of small amounts of polyfarnesene, as Krasol F 3000 (between 5 and 30 mg per 14.7 g of monomers) lead to the generation of a branched butyl product. The branching effectiveness of polyfarnesene is much higher than the SBS resins used by EMC, as loadings greater than 200 mg per polymerization of similar scale was required to give a product with less branching, as per rheological measurements (Table 10). Polyfarnesene was added to butyl polymerizations up to 100 mg before poisoning of the reaction was observed. Comparison of EMC 6222 and polymers containing various amounts of polyfarnesene are shown using a van Gurp-Palmen plot in Fig. 10. These plots demonstrate the differences in the amount of branching and the number of short chains by looking at the d at G* = 8,000 Pa and the d at G* = 300,000 Pa. Rheological analysis using the van Gurp-Palmen plot allowed for the use of design of experiments (DoE) to determine the recipe of polyfarnesene and chain transfer agent that is required to generate a branched polymer with similar branching, number of short chains and modulus to EMC 6222. One recipe contains 20 mg of polyfarnesene added to the polymerization along with a higher amount of diisobutylene (DIB) as the chain transfer agent, the other with 10.8 mg of polyfarnesene and a lower amount of DIB. The rheological analysis of these two recipes and the competitor EMC 6222 material are shown in Fig. 11.

Table 10

Example 8 Different polyfarnesenes

Other branching agents that have not been previously reported in the prior art were explored. Various versions of polyfarnesene with a range of molecular weights (from 1200 to 130,000 g/mol, 1,4-co-1,2 and solely 1,4- polymers, linear and star branched varieties) were screened as branching agents for butyl rubber. The degree of polymerization ranged from 5 to 636. The range of polymers tested also varied the enchainment type (1,2-co-1,4 or solely 1,4), linear or branched and hydroxy-terminated and not. They also include other comonomers, such as butadiene for two examples (Table 11). The prior art also suggests many other comonomers for farnesene, including: isoprene, styrene, alpha and para-methylstyrene, myrcene and ocimene. The rheological data comparing all of the polyfarnesene polymers as branching agents for butyl rubber are shown in Fig. 12 and Fig. 13.

Table 11

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

36

RECTIFIED SHEET (RULE 91.1) Total-Cray Valley as Krasol F 3100, was screened as a branching agent for butyl rubber. 100 mg of Krasol F 3100 was added to a butyl rubber polymerization and the resultant polymer was analyzed using a van Gurp-Palmen plot. The polymer produced with Krasol F 3100 was compared to a glovebox control, as well as examples containing 20 mg of Krasol F 3000, and was found to be linear, with a similar curve profile to the glovebox control, shown in Fig. 14.

Example 10- Different branching agents

Other cyclic polyterpenes were screened for their ability to generate branched butyl rubber. 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. It was shown that there was no difference in rheology between control experiments and experiments with 100 mg of cyclic polyterpene added. These materials tested were low molecular weight (<1000 g/mol) which could be the reason why no branching was observed (Fig. 15). While they could potentially result in a branched butyl rubber, this cannot be confirmed at this time and at these loadings, and as such, may be studied further later.

Example 11 - Solution Polymerization

The addition of polyfarnesene to solution polymerizations of butyl rubber in hexane has also been successfully performed (Table 12). MR and the analogous version with polyfarnesene were prepared and analyzed using MCR. These data are shown in Fig. 16. Branching is observed when polyfarnesene is introduced into the monomer feed.

Table 12 Example 12- Characterization ofPF-IIR

To demonstrate the presence of polyfarnesene in the PF-IIR samples produced and to confirm it is chemically bound within the polymer matrix, beyond the rheological data changes, ¹ H NMR spectroscopy, pyrolysis-GCMS and GPC methods were used.

A butyl rubber sample normally has 0.9 to 2.5 mol% isoprene, in the form of 1,4 enchainment and branched microstructure, which undergoes a hydride shift, resulting in a branch point at isoprene. The signals for these two functionalities are found around 5.1 ppm (triplet) and 4.9 ppm (doublet) in the ¹ H NMR spectrum, respectively. When polyfarnesene is added as a branching agent to a butyl polymerization, the resultant polymer appears no different by ¹ H NMR (Fig. 17). Farnesene itself is a sesquiterpene, meaning it is comprised of 3 isoprene units, two of which are 1,4 enchained, which is the exact same structure found in butyl rubber. The isoprene subunit in farnesene that is used to polymerize to generate polyfarnesene is also primarily found in the 1 ,4 structure. Additionally, despite the PF-IIR sample having 40% 1,2 enchainment in the polymer backbone, the quantity of this functionality in the polyfarnesene and the quantity of polyfarnesene in the rubber is too low for detection by ¹ H NMR.

Pyrolysis-GCMS demonstrated that polyfarnesene was chemically bound to the butyl polymer chains and was not simply behaving as an additive causing alternate rheological behaviour. A sample of PF-IIR 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 a pyrolysis-GCMS chromatogram demonstrates a signal at a retention time of approximately 15.1 minutes that is present in a sample of pure polyfarnesene (dark grey trace) and PF-IIR (light grey trace), but not present in a normal lab-produced butyl rubber sample (black trace) (Fig. 18). Another signal at 16.4 min shows the same pattern. 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 rate 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 analyze the PF-IIR polymers formed. 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 um 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. 19 demonstrates a chromatogram of a control lab-produced butyl rubber, as well as three PF-IIR samples with varying amounts of polyfarnesene and diisobutylene. The chromatograms show that the control signal is quite symmetric, in contrast to all three PF-IIR samples. The sample with the highest amount of PF and no DIB shows the most pronounced shoulder, demonstrating a bimodal distribution with a linear fraction and a higher molecular weight fraction. This shoulder decreases in intensity as DIB is added to the polymerization and again when the polyfarnesene loading is decreased.

Example 13- Process variations using Polyfarnesene Maintaining high molecular weight at increased temperatures

Polyfarnesene can be used as a polymerization additive to modify the properties of the polymer produced under a given set of conditions. Low levels of polyfarnesene were added to polymerizations conducted at higher temperatures to determine whether it had the effect of increasing the molecular weight of the polymer produced, to match control butyl rubber produced at lower temperatures. Butyl rubber controls produced in the lab have a Mw between 500,000 and 700,000 g/mol, and the results from a day of experiments is considered valid when the molecular weight is above 500,000 g/mol. The addition of a small amount of polyfarnesene to a polymerization performed at -80°C gave a butyl polymer with a molecular weight comparable to the control reaction at -90°C. Similarly, the addition of polyfarnesene to a polymerization produced at -70°C still produced a polymer with a Mw above 500,000 g/mol (Table 13).

Table 13 Increased PDI butyl rubber with lower oligomer content

Polyfarnesene was also used in an attempt to produce a polymer with lower oligomers and a comparable or higher polydispersity (PDI) than a control sample. Butyl rubber oligomers, CI ₃ H ₂ 4 and C ₂ IH _O , are by products of the polymerization process. The amount of oligomers in a sample of butyl rubber is dependent on the polymerization conditions, such as temperature and monomer concentration. One way to reduce the oligomer content in butyl rubber is to reduce the catalyst loading while trying to maintain an adequate conversion. Reducing the amount of initiator present lowers the amount of oligomers, but also the number of short chains being formed, decreasing the PDI. As lower PDI values generally indicate poor processability, finding a method to reduce oligomers while also increasing PDI would be beneficial to butyl rubber properties.

A series of experiments were performed where polyfarnesene was added to butyl polymerizations, and the oligomer content was measured for each polymer (Table 14). Additionally, to compare and contrast the ability of polyfarnesene to reduce the amount of oligomers while also raising the PDI, polymerizations with a butadiene polymer branching agent, namely ARL CB380, a lithium butadiene rubber, were performed. Previous work had shown that polyfarnesene had 5x the effectiveness as a branching agent as CB380, therefore, 5x the amount of CB380 was used. It was found that the addition of low levels of polyfarnesene did not have a significant impact on the polymer yield, but increased the PDI and while reducing the oligomer content. Conversely, the addition of CB380 did not reduce the oligomers content as substantially and at the higher loading, gave a lower PDI than polyfarnesene. This is likely due to the Mn of the polymer produced with the higher level of CB380 as it was higher than observed for the higher loading of polyfarnesene; the impact of polyfarnesene seems to keep Mn lower while increasing Mw, thereby increasing the PDI.

Table 14 Example 14- Raw polymer analyses

Creep compliance and green strength

The polyfarnesene-butyl (PF-IIR) recipes that were scale up were both analyzed as raw polymers. The raw polymer properties demonstrated that glovebox polymer produced with polyfarnesene as a branching agent led to improved creep compliance (Fig. 20) and higher green strength (Fig. 21) in comparison to commercial ARLANXEO regular butyl polymers with higher Mooney viscosity (Table 15).

Table 15 Aged properties

An accelerated aging study at 50°C was performed on two samples of PF-IIR. It was found that after aging, there was a slight improvement in creep compliance at 2 years theoretical age vs 6 months theoretical age. This is shown in Fig. 22. It would be expected that a sample of regular butyl rubber would degrade after aging, which would negatively affect the creep compliance, resulting in worse performance after 2 years accelerated aging. The PF-IIR appears to maintain its flow properties even after aging. This could be due to the presence of polyfarnesene, as the small, localized areas of unsaturation could undergo cross-linking or due to the effect of the branching morphology on the properties of the aged polymer. Example 15- Highly branched PF-IIR alternative to cross-linked butyl rubber

A highly branched grade of regular butyl rubber was also created in the lab. This involved the use of higher levels of polyfarnesene with less or no DIB (Table 16). Polymers were prepared with similar branching to commercial Kalar cross-linked butyl rubber (Fig. 23), but with improved creep (Fig. 24). Kalar is produced from regular butyl rubber (i.e., RB301), where a peroxide resin is used to cross-link the rubber through the unsaturation in the polymer. This is a post-modification step that is not required when using polyfarnesene as a branching agent, as an equivalent product can be produced, without consuming the unsaturation. This could allow for additional curing of a formulation containing PF-IIR in place of Kalar or other cross-linked butyl rubber

Table 16

Example 16- Innertube (blac filled) compound of PF-IIR

In an inner tube compound, the polyfarnesene-butyl rubber out performed commercial rubber of higher Mooney viscosity and glovebox control rubber of similar Mooney viscosity in many properties. Table 17 demonstrates the raw polymer properties for the PF-IIR samples used in this study. Table 18 gives the innertube formulation used in the example. Table 19 gives the compound properties for the samples included in the innertube study. Fig. 25 shows the cure behavior for the compounds prepared. Improvements were observed in filler dispersion (Fig. 26) and processability (Fig. 27), and nearly matched the performance of RB301 that is normally used in this type of compound, in terms of green strength. The branching that is imparted to the butyl polymer by the polyfarnesene is thought to disrupt filler aggregation, improving the filler dispersion. In terms of processability, achieving the same Mooney viscosity as the glovebox control rubber, while also having more short chains, improves the behaviour of the PF-IIR polymer while mixing and compounding.

Table 17

Table 18 Table 19

Example 17- Curing bladder (black filled) compound of PF-IIR

An initial curing bladder mixing study demonstrated that PF-IIR had higher mixer torque and improved processability compared to RB301. The permeability was unaffected by the presence of polyfarnesene in the rubber.

A larger mix with higher Mooney PF-IIR samples was undertaken, as well as additional testing to determine other potential improvements polyfarnesene-branched butyl rubber has on physical properties of a curing bladder compound. The formulation is shown in Table 20 and the compound properties are shown in Table 21. PF-IIR showed similar physical properties and improved processability but did not demonstrate better filler dispersion as observed in other PF compounding studies. It also only maintained compound green strength of similar Mooney viscosity raw polymers. The lack of improvement in terms of filler dispersion and green strength is likely due to the high amount of resin in the compound. It should be noted that better processability was still achieved for equivalent green strength materials. There was no impact on tear, aged tear, aged stress strain and dynamically aged stress strain or permeability of the final material. These data are shown in Fig. 28 to Fig. 33.

Table 20

Table 21

Example 18- Highly filled black compound of PF-IIR

Compounding studies in other cure systems with higher Mooney PF-IIR samples were undertaken, as well as additional testing to determine other potential improvements polyfarnesene-branched butyl rubber has on physical properties. Both innertube and curing bladder compounds contain high amounts of oil or resin, which can mask processability and green strength effects, making it difficult to observe any changes between samples. To overcome this, a lower oil, highly filled carbon black compound was investigated to exaggerate improvements with PF-IIR. A white filled medical compound was also evaluated to look at the impact in a second filler system. The raw polymer properties for the materials in these mixes are described in Table 22.

Table 22 In the lower oil, highly filled black compound, the formulation for which is shown in Table 23, PF-IIR showed some improved physical properties (i.e., higher modulus) and improved processability (Table 24). Better filler dispersion was also demonstrated by Payne effect by RPA as well as cured filler dispersion by DMA. Compound green strength was maintained of similar Mooney viscosity raw polymers. These data are shown in Fig. 34 to Fig. 40.

Table 23

Table 24

Example 18- Pharmaceutical (white filled) compound of PF-I I R

In the medical white filled compound, the formulation for which is shown in Table 25, PF-IIR showed improved physical properties (i.e., higher modulus) in addition to the improved processability observed in other systems (Table 26). Slightly better filler dispersion was also demonstrated by Payne effect by RPA. Compound green strength was also improved in PF compounds compared to similar Mooney viscosity raw polymers. These data are shown in Fig. 41 to Fig. 46. Table 25

Table 26

Example 19- Chlorinated polyfarnesene-butyl rubber

As with most butyl rubbers, halogenation of the rubber is an important modification to use the material in a variety of applications, including innerliners and pharmaceutical stoppers. As such, the PF-IIR material was halogenated. A chlorinated version was generated using an ARLANXEO technique with sodium hypochlorite and acetic acid (Table 27). The chlorination was efficient and gave a PF-CIIR rubber with approximately 0.9 mol% exo-CFh functionality. MCR analysis using a van Gurp-Palmen plot demonstrated that the PF-CIIR was branched as shown in Fig. 47. Raw polymer testing demonstrated improved creep compliance (Fig. 48) and green strength (Fig. 49) with polyfarnesene branched chlorobutyl rubber.

Table 27

Example 20 Innerliner (black filled) compound of PF-CIIR

A small head mix with the PF-CIIR samples (Table 28) to determine potential improvements polyfarnesene-branched butyl rubber has on physical properties of an innerliner compound was completed, using the formulation in Table 29. PF-CIIR shows improvements in physical properties to a lab generated chlorobutyl rubber of a similar Mooney viscosity, while having no effect on the permeability of the innerliner compound (Table 30). As shown in Fig. 50, the torque evolution during the mix was higher with the PF-CIIR in comparison to other rubbers tested, but as shown in Fig. 51 the filler dispersion was maintained instead of improved in this system. In Fig. 52, the cure state of the PF-CIIR compound was slightly higher than the CB1240 lab sample, which had similar Mooney viscosity and Cl content. The cure rate is lower for the PF-CIIR, but this could be attributed to the higher volatiles indicating some remaining reactants or moisture in the product when mixing. Fig. 53 demonstrates the improved processability imparted by the presence of the branching agent in PF-CIIR and Fig. 54 demonstrates PF-CIIR having higher green strength than a non-branched rubber. Similar, Fig. 55 shows the cured modulus of the innerliner compounds with lab prepared CNR and PF-CIIR. Overall, this compounding study demonstrated that PF-CIIR is a much better processing polymer than CNR of similar Mooney.

Table 28

Table 29

Table 30

Example 21 Pharmaceutical stopper (white filled) compound ofPF-CIIR

A slightly less branched PF-CIIR polymer was then used in a pharmaceutical stopper compounding study (Table 31), where it was again compared to two CNR samples, a lab chlorinated CNR and CB1240. Similar to the innerliner formulation, many benefits were observed with the PF-CIIR material, where it exceeded a similar Mooney CNR control in most tests (Table 32). Increases in mixer torque (Fig. 56) and improvements in M _H -M _L (Fig. 57), filler dispersion (Fig. 58), processability (Fig. 59) and green strength (Fig. 60) were demonstrated in comparison to the lab polymer tested. On top of these benefits that were also seen in the innerliner mix, the cured modulus (Fig. 61) and compression set (Fig. 62) were improved with PF-CIIR in comparison to other polymers indicating a higher cure state with the polyfarnesene branched rubber. As with the innerliner study, the introduction of polyfarnesene into the polymer matrix did not impact the permeability of the pharmaceutical compound.

Table 31 Table 32

Example 22 - Brominated polyfarnesene butyl rubber

The polyfarnesene butyl rubber was brominated at small scale to give a branched bromobutyl alternative to EMC 6222. As is the case with small batch reactors, the bromination of butyl rubber often gives a high amount of rearranged microstructure (CH ₂ - X) in comparison to plant produced material. As such, a DoE was undertaken on BB2030 base rubber to determine the optimal conditions to minimize the rearranged product, while also maximizing the exo-CH ₂ microstructure. It was found that 10 wt% rubber, 35 wt% water and 55 wt% hexanes gave the optimal conditions to give ~0.7 mol% exo-CH ₂ and <0.2 mol% CH ₂ -X. When brominating PF-IIR for compounding studies, it was found that to meet the targets of 0.9 mol% total functional bromine and 1400 ppm Ca, slightly more bromine and calcium stearate were required to achieve those targets, in comparison to the control material. The brominated raw polymer was compared to lab brominated BIIR from BB2030 base material obtained from the ARLANXEO Sarnia site, and to commercial ARLANXEO BIIR grades, BB2030 and BBX2. Two different BB2030 batches were analyzed: one had a Mooney viscosity of 34 MU, whereas the BB2030 retains had a Mooney of 29, which more closely matched the PF-BIIR batches, which had Mooney viscosities of 29. Additional polyfarnesense samples were created to match the Mooney of BBX2 at both low and high branching levels (Table 33). van gurp-Palmen plots were generated to show that these polymers were branched by the incorporation of PF (Fig. 63). The creep compliance of the polymers at 100 °C was tested using an Anton Paar MCR instrument (Fig. 64). The data demonstrated that all polyfarnesene bromobutyl rubbers had improved creep compliance in comparison to similar Mooney viscosity linear polymers. The initially higher slope for the PF-BIIRs demonstrated the impact of the short chains of the polymer, giving an indication that they will have improved processability, but the lowered slope at the end of the curve indicated better long-term dimensional stability (Fig. 64). The green strength of the raw polymers was also measured using the MCR and demonstrated that the peak stress of the PF-BIIR samples outperformed all production and lab samples of similar Mooney viscosity (Fig. 65). One of the lower Mooney PF-BIIR samples was very similar in terms of green strength to BBX2, and one of the higher Mooney PF-BIIR samples was more than double BBX2. This demonstrates the large impact that a small amount of branching agent can have on the physical properties of the rubber.

Table 33

Example 23 Innerliner (black filled) compound of PF-BIIR

A large head mix with PF-BIIR samples with equivalent Ca and Br levels were undertaken (Table 34), as well as additional testing to determine other potential improvements polyfarnesene-branched butyl rubber has on physical properties of an innerliner compound. The formulation is given in Table 35. PF-BIIR shows improvements in physical properties to BB2030 of a similar Mooney viscosity, while having no effect on the permeability of the innerliner compound (Table 36). As shown in Fig. 66, the torque evolution during the mix was higher with the PF-BIIR in comparison to all other rubbers tested. Higher mixer torque could lead to benefits in reduced mixing time, while maintaining the required filler dispersion required for a given compound. In Fig. 67, the cure rate and state of the PF-BIIR compounds were similar to the BB2030 retains, which had similar Mooney viscosities. At high Mooney viscosity, as the PF increased to very high amounts (15 PF), there is an observed drop in MH in the MDR. This translated over to a reduced cure state in the stress strain modulus as well. Fig. 68 shows the benefits observed in filler dispersion of an innerliner formulation with PF-BIIR; even the lower MV PF-BIIR have much improved filler dispersion compared to commercial BB2030 and similar filler dispersion to a much higher Mooney material BBX2. Fig. 69 demonstrates the improved processability imparted by the presence of the branching agent in PF-BIIR, where a lower Mooney PF branched material behaves like a higher Mooney linear material across a frequency sweep. Fig. 70 demonstrates higher green strength than a non-branched rubber of similar Mooney viscosity as tested on the T2000 instrument. Fig. 71 demonstrates a similar result in the higher Mooney viscosity PF-BIIR materials on the Instron tensile tester. Due to differences in the extensometer these could not be all graphed on the same plot. The improved green strength with improved processability is due to an increase in branching alongside an increase in number of short chains. Overall, this compounding study demonstrated that even with a low Mooney viscosity material, PF-BIIR has much better processing than BB2030 of similar Mooney and in some cases, exceeds the performance of the much higher Mooney BBX2 and has improved green strength to a similar Mooney BB2030. A higher Mooney viscosity PF-BIIR processes better than commercial high Mooney viscosity butyl rubber BBX2 and again has improved green strength compared to any ARL commercial bromobutyl rubber. The aged properties of the innerliner compounds were also tested, and PF-BIIR aged similarly to commercial bromobutyl.

Table 34

Table 35

Table 36

Innerliner compound with added polyfarnesene

A small head innerliner study was undertaken to ensure the effect of polyfarnesene was from the branching of the polymer and not the addition of the polymer itself. 0.2 phr polyfarnesene was mixed into a compound to represent a high amount of branching agent vs. BB2030 alone (Table 37). The variation from peak mixer torque from the above table is due to the change in mixer size. There was no positive impact on the mixing torque (Fig. 72), cure behaviour (Fig. 73), filler dispersion (Fig. 74), processing (Fig. 75) or green strength (Fig. 76) of BB2030 by mechanical addition of this small amount of polyfarnesene. Additional green strength data from previous innerliner mixes above was included in Fig. 76 below to show that the 0.25 MPa value for BB2030 was low, and that the addition of PF does not cause an increase in green strength. Finally, the cured modulus of the compound was unchanged with the additional of polyfarnesene to the formulation (Fig. 77).

Table 37

Innerliner compound of PF-BI I R blended with natural rubber

An additional innerliner study was undertaken as a blend of bromobutyl rubber with natural rubber as shown in Tables 38 and 39. The green strength was not measured, but the higher mixer torque (Fig. 78) was maintained in this study. There was no change in cure behaviour (Fig. 79) or filler dispersion (Fig. 80) compared to other innerliner studies, likely due to the dilution of the PF-BIIR polymer due to natural rubber. Processability improvements continued in this study (Fig. 81). Again, there were no changes in physical properties or permeability for these compounds.

Table 38 Table 39

Example 24 Innerliner compound of PF-BIIR with lower oil loading

An additional innerliner study was undertaken as an attempt to lower the oil in the formulation and improve the permeability by substituting PF-BIIR for BIIR (Table 40). When the amount of oil is reduced in the bromobutyl control rubber, the compound Mooney viscosity is increased (Table 41) and the filler dispersion worsened (Fig. 82). Conversely, it was found that polyfarnesene branched butyl rubber could maintain the compound Mooney viscosity and filler dispersion by using 5 phr of oil. The processability of the PF-BIIR with lower oil maintained the processability improvements observed with other innerliner compounding studies (Fig. 83). The green strength of the compounds demonstrated the expected effect of reducing the oil (Fig. 84). The reduction of oil loading resulted in a 10% improvement in permeability (Fig. 85). Table 40

Table 41 Example 25 Pharmaceutical stopper (white filled) compound of PF-BIIR

Similar PF-BIIR polymers were then used in a pharmaceutical stopper compounding study, where they were again compared to two BB2030 samples, a lab brominated BIIR and BBX2. As another control, a BB2030 sample was again spiked with 0.2 phr of polyfarnesene (Table 42) to show the improvement was from the branching with polyfarnesene and could not be achieved by mechanical mixing. Similar to the innerliner formulation, many benefits were observed with the PF-BIIR material, where it exceeded a similar Mooney BB2030 control in most tests (Table 43). Increases in mixer torque (Fig. 86), cure state by torque in the MDR (Fig. 87) improvements in filler dispersion (Fig. 88, 89), processability (Fig. 90) and green strength (Fig. 91) were demonstrated in comparison to linear polymers of similar Mooney viscosity tested. On top of these benefits that were also seen in the innerliner mix, improvements in cured modulus (Fig. 92, Fig. 93), die B and die C tear strength and compression set were also observed in comparison to similar Mooney viscosity polymers. There were a few differences between day 1 and day 2 samples for unknown reasons, so the filler dispersion and tensile strength are separated into 2 graphs, but improvements against controls are seen in each. As with the innerliner study, the introduction of polyfarnesene into the polymer matrix did not impact the permeability of the pharmaceutical compound.

Table 42

Table 43

In many compounding studies, the mixer torque was shown to be higher during the mixing stage of the study for polyfarnesene branched butyl. This was seen for most formulations and with all PF-(X)IIR samples, in comparison to the linear, commercial analogues. The reason for this is unknown at this time. It is also unclear whether this increase in torque is causing or a result of improved filler dispersion. It is also thought that increased mixer torque and filler dispersion could indicate that to achieve an identical level of dispersion, a customer could mix for less time, leading to reduced energy costs or higher throughput. Several studies have been performed at the lab scale to recreate this, but the methods used to this point were unsuccessful.

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.