RU2808455C2 - Method for producing isoolefin polymers using tertiary ether - Google Patents

Abstract

FIELD: production of butyl rubbers.

SUBSTANCE: proposed method for producing isoolefin polymers by preparing a reaction medium containing a single diluent, an isoolefin, a multiolefin and an aluminum compound with a tertiary ether as an initiating system, where the molar ratio of the tertiary ether to the sum of aluminium atoms from the aluminium compounds used is from 0.001 to 0.200, followed by polymerization of monomers in a reaction medium in presence of a given initiator system at a temperature ranging from -100°C to -60°C to form the resulting medium, wherein the resulting isoolefin polymer contains butyl rubber having a molar ratio of 1,4-isoprene to branched structure from 14.0 to 20.0; variants of butyl rubbers for manufacturing of rubber products obtained by the proposed method, and a mixture containing the proposed butyl rubber.

EFFECT: provision of a universal method for producing high-quality isoolefin polymers, such as polyisobutene or butyl rubber, with improved process control.

13 cl, 7 tbl, 6 ex

Description

Field of technology to which the invention relates

The invention relates to an effective method for producing isoolefin polymers, such as polyisobutene or butyl rubber, by polymerizing isobutene and optionally additional monomers in the presence of an initiator system containing at least one boron or aluminum compound and at least one secondary or tertiary alkyl ether.

State of the art

Polymers containing repeating units derived from isoolefins are produced on an industrial scale through carbocationic polymerization. Of particular importance are polyisobutene and butyl rubber, which is a copolymer of isobutylene and a smaller amount of multiolefin (polyene) such as isoprene.

Carbocationic polymerization of isoolefins and their copolymerization with multiolefins has a complex mechanism. The initiator system typically consists of two components: an initiator and a Lewis acid, such as aluminum trichloride, which is often used in large-scale commercial processes.

Examples of initiators include proton sources such as hydrogen halides, alcohols, phenols, carboxylic and sulfonic acids, and water.

In the initiation step, the isoolefin reacts with a Lewis acid and an initiator to form a carbenium ion, which then reacts with the monomer to form a new carbenium ion in what is called the chain propagation step.

The type of monomers, the type of diluent or solvent and its polarity, the polymerization temperature, and the particular combination of Lewis acid and initiator influence the chain propagation chemistry and therefore the incorporation of the monomer into the growing polymer chain.

It is common practice in industry to use the suspension polymerization process to produce polyisobutylene, butyl rubber and other isoolefin polymers in methyl chloride as a diluent. Typically, the polymerization process is carried out at low temperatures, typically below -90°C. Alkyl chlorides, particularly methyl chloride, are used for a variety of reasons, including the fact that it dissolves the monomers and the initiator aluminum chloride, but not the polymer product. Methyl chloride also has suitable freezing and boiling points to provide, respectively, low temperature polymerization and efficient separation from the polymer and unreacted monomers. The method of suspension polymerization in methyl chloride provides the advantage that it is possible to achieve a polymer concentration in the reaction mixture of up to 40% by weight. and higher, in contrast to the technically achievable maximum polymer concentration of 20 wt%. during polymerization in solution, depending on the given molecular weight. It is necessary to maintain a suitable, relatively low viscosity of the polymerization solution, which allows the heat of polymerization to be removed by heat exchange through the surface of the reaction apparatus. In the production of high molecular weight polyisobutylene polymers and isobutylene-isoprene butyl rubbers, polymerization methods in suspension and solution in methyl chloride or alkanes are used.

Alternatively, aliphatic solvents such as normal and isopentanes and hexanes, as well as mixtures thereof, are used for polymerization, as for example disclosed in WO2010/006983A and WO2011/089092A, which have significant advantages in subsequent processing, for example chemical modification polymer.

An isoolefin polymer, such as polyisobutene or butyl rubber produced by polymerization, dissolves in this aliphatic medium and is therefore commonly referred to as solution processes.

A common feature of both suspension and solution processes is that, due to the high reactivity of the initiators used, it is difficult but critical to control the temperature and avoid so-called “local hot spots” due to the heterogeneity of the polymerization medium. achieving the desired product quality and preventing contamination of the reactor, that is, the formation of polymer deposits on the surface of the reactor. Such deposits, due to their insulating effect, reduce cooling efficiency and can cause the temperature inside the reactor to rise rapidly, thereby increasing the rate of exothermic polymerization and rapidly releasing additional heat, which is again not sufficiently removed. Eventually, it may even lead to thermal runaway.

Several attempts have been made in the past to provide external or internal cooling in order to maintain the desired (low) temperature inside the reactor.

Other attempts have been made by replacing the commonly used aluminum and boron initiators with other less reactive initiators or by modifying them with bulky fluorinated substituents to provide a more uniform heat distribution during polymerization. However, these attempts were economically unrealistic.

Therefore, there remains a need to provide a universal method for producing high quality isoolefin polymers with improved process control.

The essence of the invention

According to one aspect of the invention, there is now provided a process for producing isoolefin polymers, a process comprising at least the following steps:

a) providing a reaction medium containing an organic diluent, at least one isoolefin monomer, and an initiator system comprising

at least one boron or aluminum compound and,

at least one tertiary ether,

And

b) polymerizing at least one monomer in a reaction medium in the presence of a given initiator system to form a resultant medium containing an isoolefin polymer, an organic diluent and optionally residual monomer(s).

Detailed Description of the Invention

The invention also covers all combinations of preferred embodiments, ranges of parameters that are disclosed hereinafter, either with each other or with the widest range or parameter disclosed.

Isoolefins and other monomers

In step a), a reaction medium is obtained containing an organic diluent, at least one isoolefin monomer, and an initiator system.

As used herein, the term isoolefin refers to compounds containing one carbon-carbon double bond, where one carbon atom of the double bond is replaced by two alkyl groups and the other carbon atom is replaced by two hydrogen atoms or one carbon atom and one alkyl group.

Examples of suitable isoolefins include isoolefins having 4 to 16 carbon atoms, preferably 4 to 7 carbon atoms, such as isobutene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene. The preferred isoolefin is isobutene.

The reaction medium may contain additional monomers that copolymerize with at least one isoolefin. Such additional monomers include multiolefins.

As used herein, the term multiolefin refers to compounds containing more than one carbon-carbon double bond, conjugated or non-conjugated.

Examples of suitable multiolefins include isoprene, butadiene, 2-methylbutadiene, 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 and 1-vinylcyclohexadiene.

Preferred multiolefins are isoprene and butadiene. Isoprene is particularly preferred.

The reaction medium may additionally or alternatively contain additional monomers that copolymerize with at least one isoolefin and are neither isoolefins nor multiolefins. Such co-monomers include β-pinene, styrene, divinylbenzene, diisopropenylbenzene, o-, m- and p-alkylstyrenes such as o-, m- and p-methylstyrene.

In one embodiment, isobutene is used as the sole monomer, with the term “sole” as used herein denoting a proportion of 99.9% by weight. or greater than the sum of all monomers used.

In another embodiment, the monomers used in step a) may contain from 80 wt%. up to 99.5% wt., preferably from 85% wt. up to 98.0% wt., more preferably from 85% wt. up to 96.5% wt., even more preferably from 85% wt. up to 95.0% wt., at least one isoolefin and from 0.5% wt. up to 20% wt., preferably from 2.0% wt. up to 15% wt., more preferably from 3.5% wt. up to 15% wt. and even more preferably from 5.0 wt%. up to 15 wt.% of at least one multiolefin based on the total mass of all monomers used.

In another embodiment, the mixture of monomers contains from 90% of the mass. up to 95% wt., at least one isoolefin and from 5% wt. up to 10% wt. multiolefin from the total mass of all monomers used. Even more preferably, the mixture of monomers contains from 92% of the mass. up to 94% wt., at least one isoolefin and from 6% wt. up to 8% by weight of at least one multiolefin monomer based on the total weight of all monomers used. A preferred isoolefin is isobutene, and a preferred multiolefin is isoprene.

If at least one multiolefin is used in the reaction medium, the multiolefin content of the final copolymers obtained is typically 0.1 mol%. or more, preferably from 0.1 mol%. up to 15 mol%, in another embodiment 0.5 mol%. or more, preferably from 0.5 mol%. up to 10 mol%, in another embodiment 0.7 mol%. or more, preferably from 0.7 to 8.5 mole%, in particular from 0.8 to 1.5, or from 1.5 to 2.5 mole%, or from 2.5 to 4.5% mol., or from 4.5 to 8.5 mol%, especially when isobutene and isoprene are used.

In another embodiment, the multiolefin content of the copolymers produced according to the invention is 0.1 mol%. or more, preferably from 0.1 mol%. up to 3 mol%, especially when isobutene and isoprene are used.

In one embodiment, the monomers are purified before use in step a), particularly if they are recycled from the optional step c). Purification of monomers can be accomplished by passing them through adsorbent columns containing suitable molecular sieves or alumina-based adsorption materials. To minimize interference with the polymerization reaction, it is preferable to reduce the total concentration of water and substances such as alcohols and other organic oxygenates that act as reaction poisons to less than about 10 ppm by weight.

Organic thinners

The term "organic diluent" covers diluting or dissolving organic chemicals that are in a liquid state under reaction conditions. Any suitable organic diluent that does not react to any appreciable extent with the monomers or components of the initiator system may be used.

However, such interactions between the diluent and the monomers or components of the initiator system are known to those skilled in the art.

In addition, the term organic diluent includes mixtures of at least two diluents.

Examples of organic diluents include chlorocarbon(s) such as methyl chloride, methylene chloride or ethyl chloride.

Additional examples of organic diluents include hydrofluorocarbons represented by the formula: C _x H _y F _z where x is an integer from 1 to 40, alternatively from 1 to 30, alternatively from 1 to 20, alternatively from 1 to 10, alternatively from 1 to 6 , alternatively from 2 to 20, alternatively from 3 to 10, alternatively from 3 to 6, most preferably from 1 to 3, where y and z are integers and are equal to at least one.

In one embodiment, the hydrofluorocarbon(s) are selected from the group consisting of saturated hydrofluorocarbons such as fluoromethane; difluoromethane; trifluoromethane; fluoroethane; 1,1-difluoroethane; 1,2-difluoroethane; 1,1,1-trifluoroethane; 1,1-,2-trifluoroethane; 1,1,2,2-tetrafluoroethane; 1,1,1,2,2-pentafluoroethane; 1-fluoropropane; 2-fluoropropane; 1,1-difluoropropane; 1,2-difluoropropane; 1,3-difluoropropane; 2,2-difluoropropane; 1,1,1-trifluoropropane; 1,1,2-trifluoropropane; 1,1,3-trifluoropropane; 1,2,2-trifluoropropane; 1,2,3-trifluoropropane; 1,1,1,2-tetrafluoropropane; 1,1,1,3-tetrafluoropropane; 1,1,2,2-tetrafluoropropane; 1,1,2,3-tetrafluoropropane; 1,1,3,3-tetrafluoropropane; 1,2,2,3-tetrafluoropropane; 1,1,1,2,2-pentafluoropropane; 1,1,1,2,3-pentafluoropropane; 1,1,1,3,3-pentafluoropropane; 1,1,2,2,3-pentafluoropropane; 1,1,2,3,3-pentafluoropropane; 1,1,1,2,2,3-hexafluoropropane; 1,1,1,2,3,3-hexafluoropropane; 1,1,1,3,3,3-hexafluoropropane; 1,1,1,2,2,3,3-heptafluoropropane; 1,1,1,2,3,3,3-heptafluoropropane; 1-fluorobutane; 2-fluorobutane; 1,1-difluorobutane; 1,2-difluorobutane; 1,3-difluorobutane; 1,4-difluorobutane; 2,2-difluorobutane; 2,3-difluorobutane; 1,1,1-trifluorobutane; 1,1,2-trifluorobutane; 1,1,3-trifluorobutane; 1,1,4-trifluorobutane; 1,2,2-trifluorobutane; 1,2,3-trifluorobutane; 1,3,3-trifluorobutane; 2,2,3-trifluorobutane; 1,1,1,2-tetrafluorobutane; 1,1,1,3-tetrafluorobutane; 1,1,1,4-tetrafluorobutane; 1,1,2,2-tetrafluorobutane; 1,1,2,3-tetrafluorobutane; 1,1,2,4-tetrafluorobutane; 1,1,3,3-tetrafluorobutane; 1,1,3,4-tetrafluorobutane; 1,1,4,4-tetrafluorobutane; 1,2,2,3-tetrafluorobutane; 1,2,2,4-tetrafluorobutane; 1,2,3,3-tetrafluorobutane; 1,2,3,4-tetrafluorobutane; 2,2,3,3-tetrafluorobutane; 1,1,1,2,2-pentafluorobutane; 1,1,1,2,3-pentafluorobutane; 1,1,1,2,4-pentafluorobutane; 1,1,1,3,3-pentafluorobutane; 1,1,1,3,4-pentafluorobutane; 1,1,1,4,4-pentafluorobutane; 1,1,2,2,3-pentafluorobutane; 1,1,2,2,4-pentafluorobutane; 1,1,2,3,3-pentafluorobutane; 1,1,2,4,4-pentafluorobutane; 1,1,3,3,4-pentafluorobutane; 1,2,2,3,3-pentafluorobutane; 1,2,2,3,4-pentafluorobutane; 1,1,1,2,2,3-hexafluorobutane; 1,1,1,2,2,4-hexafluorobutane; 1,1,1,2,3,3-hexafluorobutane, 1,1,1,2,3,4-hexafluorobutane; 1,1,1,2,4,4-hexafluorobutane; 1,1,1,3,3,4-hexafluorobutane; 1,1,1,3,4,4-hexafluorobutane; 1,1,1,4,4,4-hexafluorobutane; 1,1,2,2,3,3-hexafluorobutane; 1,1,2,2,3,4-hexafluorobutane; 1,1,2,2,4,4-hexafluorobutane; 1,1,2,3,3,4-hexafluorobutane; 1,1,2,3,4,4-hexafluorobutane; 1,2,2,3,3,4-hexafluorobutane; 1,1,1,2,2,3,3-heptafluorobutane; 1,1,1,2,2,4,4-heptafluorobutane; 1,1,1,2,2,3,4-heptafluorobutane; 1,1,1,2,3,3,4-heptafluorobutane; 1,1,1,2,3,4,4-heptafluorobutane; 1,1,1,2,4,4,4-heptafluorobutane; 1,1,1,3,3,4,4-heptafluorobutane; 1,1,1,2,2,3,3,4-octafluorobutane; 1,1,1,2,2,3,4,4-octafluorobutane; 1,1,1,2,3,3,4,4-octafluorobutane; 1,1,1,2,2,4,4,4-octafluorobutane; 1,1,1,2,3,4,4,4-octafluorobutane; 1,1,1,2,2,3,3,4,4-nonafluorobutane; 1,1,1,2,2,3,4,4,4-nonafluorobutane; 1-fluoro-2-methylpropane; 1,1-difluoro-2-methylpropane; 1,3-difluoro-2-methylpropane; 1,1,1-trifluoro-2-methylpropane; 1,1,3-trifluoro-2-methylpropane; 1,3-difluoro-2-(fluoromethyl)propane; 1,1,1,3-tetrafluoro-2-methylpropane; 1,1,3,3-tetrafluoro-2-methylpropane; 1,1,3-trifluoro-2-(fluoromethyl)propane; 1,1,1,3,3-pentafluoro-2-methylpropane; 1,1,3,3-tetrafluoro-2-(fluoromethyl)propane; 1,1,1,3-tetrafluoro-2-(fluoromethyl)propane; fluorocyclobutane; 1,1-difluorocyclobutane; 1,2-difluorocyclobutane; 1,3-difluorocyclobutane; 1,1,2-trifluorocyclobutane; 1,1,3-trifluorocyclobutane; 1,2,3-trifluorocyclobutane; 1,1,2,2-tetrafluorocyclobutane; 1,1,3,3-tetrafluorocyclobutane; 1,1,2,2,3-pentafluorocyclobutane; 1,1,2,3,3-pentafluorocyclobutane; 1,1,2,2,3,3-hexafluorocyclobutane; 1,1,2,2,3,4-hexafluorocyclobutane; 1,1,2,3,3,4-hexafluorocyclobutane; 1,1,2,2,3,3,4-heptafluorocyclobutane.

Particularly preferred HFCs include difluoromethane, trifluoromethane, 1,1-difluoroethane, 1,1,1-trifluoroethane, fluoromethane and 1,1,1,2-tetrafluoroethane.

In yet another embodiment, the hydrofluorocarbon(s) are selected from the group consisting of unsaturated hydrofluorocarbons such as vinyl fluoride; 1,2-difluoroethene; 1,1,2-trifluoroethene; 1-fluoropropene, 1,1-difluoropropene; 1,2-difluoropropene; 1,3-difluoropropene; 2,3-difluoropropene; 3,3-difluoropropene; 1,1,2-trifluoropropene; 1,1,3-trifluoropropene; 1,2,3-trifluoropropene; 1,3,3-trifluoropropene; 2,3,3-trifluoropropene; 3,3,3-trifluoropropene; 2,3,3,3-tetrafluoro-1-propene; 1-fluoro-1-butene; 2-fluoro-1-butene; 3-fluoro-1-butene; 4-fluoro-1-butene; 1,1-difluoro-1-butene; 1,2-difluoro-1-butene; 1,3-difluoropropene; 1,4-difluoro-1-butene; 2,3-difluoro-1-butene; 2,4-difluoro-1-butene; 3,3-difluoro-1-butene; 3,4-difluoro-1-butene; 4,4-difluoro-1-butene; 1,1,2-trifluoro-1-butene; 1,1,3-trifluoro-1-butene; 1,1,4-trifluoro-1-butene; 1,2,3-trifluoro-1-butene; 1,2,4-trifluoro-1-butene; 1,3,3-trifluoro-1-butene; 1,3,4-trifluoro-1-butene; 1,4,4-trifluoro-1-butene; 2,3,3-trifluoro-1-butene; 2,3,4-trifluoro-1-butene; 2,4,4-trifluoro-1-butene; 3,3,4-trifluoro-1-butene; 3,4,4-trifluoro-1-butene; 4,4,4-trifluoro-1-butene; 1,1,2,3-tetrafluoro-1-butene; 1,1,2,4-tetrafluoro-1-butene; 1,1,3,3-tetrafluoro-1-butene; 1,1,3,4-tetrafluoro-1-butene; 1,1,4,4-tetrafluoro-1-butene; 1,2,3,3-tetrafluoro-1-butene; 1,2,3,4-tetrafluoro-1-butene; 1,2,4,4-tetrafluoro-1-butene; 1,3,3,4-tetrafluoro-1-butene; 1,3,4,4-tetrafluoro-1-butene; 1,4,4,4-tetrafluoro-1-butene; 2,3,3,4-tetrafluoro-1-butene; 2,3,4,4-tetrafluoro-1-butene; 2,4,4,4-tetrafluoro-1-butene; 3,3,4,4-tetrafluoro-1-butene; 3,4,4,4-tetrafluoro-1-butene; 1,1,2,3,3-pentafluoro-1-butene; 1,1,2,3,4-pentafluoro-1-butene; 1,1,2,4,4-pentafluoro-1-butene; 1,1,3,3,4-pentafluoro-1-butene; 1,1,3,4,4-pentafluoro-1-butene; 1,1,4,4,4-pentafluoro-1-butene; 1,2,3,3,4-pentafluoro-1-butene; 1,2,3,4,4-pentafluoro-1-butene; 1,2,4,4,4-pentafluoro-1-butene; 2,3,3,4,4-pentafluoro-1-butene; 2,3,4,4,4-pentafluoro-1-butene; 3,3,4,4,4-pentafluoro-1-butene; 1,1,2,3,3,4-hexafluoro-1-butene; 1,1,2,3,4,4-hexafluoro-1-butene; 1,1,2,4,4,4-hexafluoro-1-butene; 1,2,3,3,4,4-hexafluoro-1-butene; 1,2,3,4,4,4-hexafluoro-1-butene; 2,3,3,4,4,4-hexafluoro-1-butene; 1,1,2,3,3,4,4-heptafluoro-1-butene; 1,1,2,3,4,4,4-heptafluoro-1-butene; 1,1,3,3,4,4,4-heptafluoro-1-butene; 1,2,3,3,4,4,4-heptafluoro-1-butene; 1-fluoro-2-butene; 2-fluoro-2-butene; 1,1-difluoro-2-butene; 1,2-difluoro-2-butene; 1,3-difluoro-2-butene; 1,4-difluoro-2-butene; 2,3-difluoro-2-butene; 1,1,1-trifluoro-2-butene; 1,1,2-trifluoro-2-butene; 1,1,3-trifluoro-2-butene; 1,1,4-trifluoro-2-butene; 1,2,3-trifluoro-2-butene; 1,2,4-trifluoro-2-butene; 1,1,1,2-tetrafluoro-2-butene; 1,1,1,3-tetrafluoro-2-butene; 1,1,1,4-tetrafluoro-2-butene; 1,1,2,3-tetrafluoro-2-butene; 1,1,2,4-tetrafluoro-2-butene; 1,2,3,4-tetrafluoro-2-butene; 1,1,1,2,3-pentafluoro-2-butene; 1,1,1,2,4-pentafluoro-2-butene; 1,1,1,3,4-pentafluoro-2-butene; 1,1,1,4,4-pentafluoro-2-butene; 1,1,2,3,4-pentafluoro-2-butene; 1,1,2,4,4-pentafluoro-2-butene; 1,1,1,2,3,4-hexafluoro-2-butene; 1,1,1,2,4,4-hexafluoro-2-butene; 1,1,1,3,4,4-hexafluoro-2-butene; 1,1,1,4,4,4-hexafluoro-2-butene; 1,1,2,3,4,4-hexafluoro-2-butene; 1,1,1,2,3,4,4-heptafluoro-2-butene; 1,1,1,2,4,4,4-heptafluoro-2-butene; and mixtures thereof.

Additional examples of organic diluents include chlorofluorocarbons.

Additional examples of organic diluents include hydrocarbons, preferably alkanes, which in a further preferred embodiment are selected from the group consisting of: n-butane, isobutane, n-pentane, methylcyclopentane, isohexane, 2-methylpentane, 3-methylpentane, 2-methylbutane, 2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2- methylheptane, 3-ethylhexane, 2,5-dimethylhexane, 2,2,4,-trimethylpentane, octane, heptane, butane, nonane, decane, dodecane, undecane, hexane, methylcyclohexane, cyclopentane, methylcyclopentane, 1,1-dimethylcyclopentane, cis -1,2-dimethylcyclopentane, trans-1,2-dimethylcyclopentane, trans-1,3-dimethylcyclopentane, ethylcyclopentane, cyclohexane, methylcyclohexane.

Additional examples of hydrocarbon diluents include benzene, toluene, xylene, ortho-xylene, para-xylene and meta-xylene.

In addition, suitable organic diluents include mixtures of at least two compounds selected from the groups of chlorocarbons, hydrofluorocarbons, chlorofluorocarbons and hydrocarbons. Specific combinations include mixtures of chlorocarbons and fluorocarbons, such as mixtures of methyl chloride and 1,1,1,2-tetrafluoroethane, in particular mixtures with 40-60% vol. methyl chloride and 40-60% vol. 1,1,1,2-tetrafluoroethane, with the above two diluents being added to a total amount of diluent of 90-100% vol., preferably up to 95-100% vol., with a potential remainder of 100% vol. includes other halogenated hydrocarbons; or mixtures of methyl chloride and at least one alkane or mixture of alkanes, such as mixtures containing at least 90% by weight, preferably 95% by weight. alkanes having a boiling point at a pressure of 1013 hPa from -5°C to 100°C or in another embodiment from 35°C to 85°C. In another embodiment, at least 99.9% by weight, preferably 100% by weight. alkanes at a pressure of 1013 hPa have a boiling point of 100°C or less, preferably from 35 to 100°C, more preferably 90°C or less, even more preferably from 35 to 90°C.

Depending on the nature of the polymerization intended for step b), the organic diluent is selected to provide suspension polymerization or solution polymerization.

Initiating system

The monomer(s) are polymerized in a reaction medium in the presence of an initiator system to form a resultant medium containing an isoolefin polymer, an organic diluent, and optionally residual monomer(s).

The initiating system contains:

at least one boron or aluminum compound and

optionally at least one tertiary ether,

at least one additional activating compound.

Suitable boron or aluminum compounds are those represented by the formula MX ₃ where M is a boron or aluminum atom and X is a halogen atom. Examples of such compounds include aluminum trichloride, aluminum tribromide, boron trifluoride, boron trichloride and boron tribromide, with aluminum trichloride being preferred.

Additional suitable boron or aluminum compounds are those represented by the formula MR _(m) X _(3-m) where M is a boron or aluminum atom and X is a halogen atom, R is a monovalent hydrocarbon radical selected from the group consisting of C ₁ -C ₁₂ alkyl and C ₇ -C ₁₄ alkylaryl radicals; and m is equal to one or two. The term "alkylaryl" refers to a radical containing both aliphatic and aromatic structures, the radical being in an aliphatic moiety.

Examples of such compounds include methylaluminum dibromide, methylaluminum dichloride, ethylaluminum dibromide, ethylaluminum dichloride, butylaluminum dibromide, butylaluminium dichloride, dimethylaluminum bromide, dimethylaluminum chloride, diethylaluminum bromide, diethylaluminum chloride, dibutylaluminum bromide, dibutylaluminum chloride, methyl Aluminum sesquibromide, methyl aluminum sesquichloride, ethylaluminum sesquibromide, ethylaluminum sesquichloride.

Preferred are diethylaluminum chloride (Et ₂ AlCl or DEAC), ethylaluminum sesquichloride (Et _1.5 AlCl _1.5 or EASC), ethylaluminum dichloride (EtAlCl ₂ or EADC), diethylaluminum bromide (Et ₂ AlBr or DEAB), ethylaluminum sesquibromide (Et _1.5 AlBr _{1, 5} or EASB) and ethyl aluminum dibromide (EtAlBr ₂ or EADB).

A particularly preferred aluminum compound is aluminum trichloride.

Ethers

Tertiary ethers as used herein are ethers bearing at least one tertiary alkyl or tertiary arylalkyl group, preferably only one tertiary alkyl or tertiary arylalkyl aryl group at the ether oxygen atom.

Preferred tertiary alkyl groups include t-butyl and t-amyl.

Preferred tertiary arylalkyl aryl groups include cumyl.

Examples of tertiary alkyl ethers include methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), methyl tert-amyl ether (MTAE) and phenyl tert-butyl ether (PTBE) or mixtures thereof, wherein preferred are methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), methyl tert-amyl ether (MTAE) or mixtures thereof, and even more preferred are methyl tert-butyl ether (MTBE).

Additional activating compounds suitable for this invention are selected from those capable of reacting with selected boron or aluminum compounds to form a complex that reacts with the monomers to form a growing polymer chain.

In a preferred embodiment, such activating compounds are selected from the group consisting of water, alcohols, phenols, hydrogen halides, carboxylic acids, carboxylic acid halides, carboxylic acid esters, carboxylic acid amides, sulfonic acids, sulfonic acid halides, alkyl halides, alkylaryl halides and polymeric halides.

Preferred alcohols include methanol, ethanol, propanol, 2-propanol, 2-methylpropan-2-ol, cyclohexanol and benzyl alcohol.

Preferred phenols include phenol; 2-methylphenol; 2,6-dimethylphenol; p-chlorophenol; p-fluorophenol; 2,3,4,5,6-pentafluorophenol and 2-hydroxynaphthalene.

Preferred hydrogen halides include hydrochloride, hydrobromide and hydroiodide. A particularly preferred hydrohalide is hydrochloride.

Preferred carboxylic acids include both aliphatic and aromatic carboxylic acids. Examples of carboxylic acids suitable for this invention include acetic acid, propanoic acid, butyric acid; cinnamic acid, benzoic acid, 1-chloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, p-chlorobenzoic acid and p-fluorobenzoic acid. Particularly preferred carboxylic acids include trichloroacetic acid, trifluoroacetic acid and p-fluorobenzoic acid.

Carboxylic acid halides useful in this invention have a structure similar to that of carboxylic acids by replacing the OH of the acid with a halide. The halide may be fluoride, chloride, bromide or iodide, with chloride being preferred.

Carboxylic acid halides useful in this invention include acetyl chloride, acetyl bromide, cinnamyl chloride, benzoyl chloride, benzoyl bromide, trichloroacetyl chloride, trifluoroacetyl chloride and p-fluorobenzoyl chloride. Particularly preferred acid halides include acetyl chloride, acetyl bromide, trichloroacetyl chloride, trifluoroacetyl chloride and p-fluorobenzoyl chloride.

Carboxylic acid esters include methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, allyl acetate, benzyl acetate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, dimethyl maleate, diethyl maleate, dipropyl maleate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, allyl benzoate, butylidene benzoate, benzyl benzoate, phenylethyl benzoate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dipentyl phthalate, dihexyl phthalate, diheptyl phthalate and dioctyl phthalate.

Carboxylic acid amides include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide and N,N-diethylacetamide. Preferred tertiary alkyl and aralkyl initiators include tertiary compounds represented by the formula below: wherein X is halogen, pseudohalogen, ether, ester or mixtures thereof, preferably halogen, preferably chloride, and R ₁ , R ₂ and R ₃ are independently any linear , cyclic or branched alkyls, aryls or arylalkyls, preferably containing from 1 to 15 carbon atoms and more preferably from 1 to 8 carbon atoms. n is equal to the number of initiator sites and is a number greater than or equal to 1, preferably from 1 to 30, more preferably n is a number from 1 to 6. Arilalkyls may be substituted or unsubstituted. For the purposes of this invention and any claims, an arylalkyl is defined as a compound containing both aromatic and aliphatic structures. Preferred examples of initiators include 2-chloro-2,4,4-trimethylpentane; 2-bromo-2,4,4-trimethylpentane; 2-chloro-2-methylpropane; 2-bromo-2-methylpropane; 2-chloro-2,4,4,6,6-pentamethylheptane; 2-bromo-2,4,4,6,6-pentamethylheptane; 1-chloro-1-methylethylbenzene; 1-chloroadamantane; 1-chloroethylbenzene; 1,4-bis(1-chloro-1-methylethyl)benzene; 5-tert-butyl-1,3-bis(1-chloro-1-methylethyl)benzene; 2-acetoxy-2,4,4-trimethylpentane; 2-benzoyloxy-2,4,4-trimethylpentane; 2-acetoxy-2-methylpropane; 2-benzoyloxy-2-methylpropane; 2-acetoxy-2,4,4,6,6-pentamethylheptane; 2-benzoyl-2,4,4,6,6-pentamethylheptane; 1-acetoxy-1-methylethylbenzene; 1-acetoxyadamantane; 1-benzoyloxyethylbenzene; 1,4-bis(1-acetoxy-1-methylethyl)benzene; 5-tert-butyl-1,3-bis(1-acetoxy-1-methylethyl)benzene; 2-methoxy-2,4,4-trimethylpentane; 2-isopropoxy-2,4,4-trimethylpentane; 2-methoxy-2-methylpropane; 2-benzyloxy-2-methylpropane; 2-methoxy-2,4,4,6,6-pentamethylheptane; 2-isopropoxy-2,4,4,6,6-pentamethylheptane; 1-methoxy-1-methylethylbenzene; 1-methoxyadamantane; 1-methoxyethylbenzene; 1,4-bis(1-methoxy-1-methylethyl)benzene; 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene and 1,3,5-tris(1-chloro-1-methylethyl)benzene.

Sulfonic acids suitable as initiators in this invention include both aliphatic and aromatic sulfonic acids. Examples of preferred sulfonic acids include methanesulfonic acid, trifluoromethanesulfonic acid, trichloromethanesulfonic acid and p-toluenesulfonic acid.

Sulfonic acid halides useful in this invention have a structure similar to that of sulfonic acids by replacing the OH of the parent acid with a halide. The halide may be fluoride, chloride, bromide or iodide, with chloride being preferred. The preparation of sulfonic acid halides from starting sulfonic acids is known in the art, and one skilled in the art should be familiar with these techniques. Preferred sulfonic acid halides useful in this invention include methanesulfonyl chloride, methanesulfonyl bromide, trichloromethanesulfonyl chloride, trifluoromethanesulfonyl chloride and p-toluenesulfonyl chloride.

Alkyl halides useful in this invention include 2-chloro-2,4,4-trimethylpentane and 2-chloro-2-methylpropane.

Alkylaryl halides useful in this invention include 1-chloro-1-methylethylbenzene.

Polymer halides useful in this invention include halides having at least two halogenated tertiary carbon atoms located at the end of the chain, along or within the polymer backbone.

The preferred molar ratio of tertiary ester to the sum of boron and aluminum atoms of the boron or aluminum compounds used is generally from 0.001 to 0.500, preferably from 0.005 to 0.500, more preferably from 0.001 to 0.200, even more preferably from 0.002 to 0.200.

The initiator system, including the Lewis acid and the initiator, is preferably present in the reaction mixture in an amount of from 0.002 to 5.0% by weight, preferably from 0.1 to 0.5% by weight. on the mass of monomers used.

In another embodiment, in particular where aluminum trichloride is used, the weight ratio of the monomers used and boron or aluminum compounds, in particular aluminum trichloride, is from 500 to 20,000, preferably from 1500 to 10,000.

In a particularly preferred initiator system, the boron or aluminum compound is ethylaluminum sesquichloride, preferably prepared by mixing equimolar amounts of diethylaluminum chloride and ethylaluminum dichloride, preferably in an organic diluent. The organic diluent is preferably the same as that used to carry out the polymerization in step b).

The above-described initiator system is also included in the invention whether it is a combination with an organic diluent or not.

In one embodiment, water is also used as an additional activating compound. In this embodiment, the amount of water is 0.1 to 4.0 moles of water per mole of boron or aluminum compound, preferably 0.2 to 2 moles of water per mole of boron or aluminum compound, most preferably 0.5 to 1 moles of water per mole of boron or aluminum compound, in particular where compounds of the formula MR _(m) X _(3-m) as described above are used.

In one embodiment where aluminum halides, in particular aluminum trichloride, are used as the boron or aluminum compound, it is preferable to use water and/or alcohols as the additional activating compound.

Reaction environment

Monomer(s) may be present in the reaction medium in an amount of from 0.01 wt%. up to 80% wt., preferably from 0.1% wt. up to 65 wt.%, more preferably from 10.0 wt.%. up to 65.0% wt. and even more preferably from 25.0 wt%. up to 65.0% wt. or in another embodiment from 5.0 wt%. up to 55.0% wt.

The organic diluent may be present in the reaction medium in an amount of from 0.01 wt%. up to 80% wt., preferably from 0.1% wt. up to 65 wt.%, more preferably from 10.0 wt.%. up to 65.0% wt. and even more preferably from 25.0 wt%. up to 65.0% wt. or in another embodiment from 10.0 wt%. up to 40.0% wt.

The amounts of organic diluent, monomers and initiator system are selected so that they constitute at least 95% by weight, preferably from 97 to 100% by weight. and more preferably from 99 to 100 wt%. reaction medium used in step b).

The remainder, up to 100%, if present, may contain other organic or inorganic compounds, preferably those that have little or no effect on the polymerization reaction.

In one embodiment, the reaction medium contains from 10.0 wt.%. up to 65.0% wt. monomer(s), from 20.0% wt. up to 89.9% wt. organic diluent and from 0.1% wt. up to 15.0% wt. carbon dioxide, wherein the amounts of organic diluent, monomer(s) and carbon dioxide are selected so that they can be at least 95% by weight, preferably from 97 to 100% by weight. and more preferably from 99 to 100 wt%. reaction environment. From the point of view of productivity and efficiency, it is desirable to increase the concentration of monomers relative to the diluent, that is, the reacting fractions of the reaction medium relative to the non-reacting ones. However, this has the side effect of increasing the thermal load on the reactor, potentially exceeding its ability to remove reaction heat. In addition to reducing reactor performance, this may lead to undesirable effects on product properties, including, but not limited to, polymer molecular weight distribution.

Polymerization conditions

In one embodiment, the organic diluent and monomers used are substantially free of water. As used herein, "substantially free of water" is defined as less than 30 ppm of the total weight of the reaction medium, preferably less than 20 ppm, more preferably less than 10 ppm, even more preferably less than 5 ppm and most preferably less than 1 ppm.

One skilled in the art will know that the water content of the diluent and monomers must be low to ensure that the initiator system is not affected by additional amounts of water not specifically added, for example, to serve as an initiator. Each step a) and b) can be performed in a continuous or batch mode, with continuous operation being preferred. Typically, the provision of the reaction medium in step a) and the initiation of polymerization in step b) are carried out simultaneously.

In an embodiment of the invention, the polymerization according to step b) is carried out using a polymerization reactor. Suitable reactors are known to those skilled in the art and include flow polymerization reactors, plug flow reactors, stirred tank reactors, moving belt or drum reactors, jet or nozzle reactors, tube reactors and self-cooled boiling tank reactors. Specific suitable examples are disclosed in WO 2011/000922 A and WO 2012/089823 A.

Depending on the choice of organic diluent, the polymerization according to step b) is carried out either as a suspension polymerization or as a solution polymerization.

In suspension polymerization, all monomers and the initiator system are usually soluble in the diluent or mixture of diluents, i.e. constitute one phase, while the copolymer, upon formation, precipitates from an organic diluent. It is desirable that reduced or no polymer "swelling" be exhibited, as indicated by little or no suppression of the polymer's Tg and/or little or no mass uptake of organic diluent. In solution polymerization, all monomers and the initiator system are usually soluble in the diluent or mixture of diluents, i.e. constitute one phase, like the copolymer formed during polymerization.

The solubilities of the desired polymers in the organic diluents described above, as well as their swelling under reaction conditions, are well known to those skilled in the art.

The advantages and disadvantages of solutions compared to suspension polymerization have been extensively described in the literature and are thus also known to those skilled in the art.

Step b) is preferably carried out as a suspension process.

In one embodiment, step b) is carried out at a temperature in the range of -100°C to -60°C, preferably -98°C to -80°C and even more preferably -97°C to -90°C.

The reaction pressure in step b) is typically 500 to 100,000 hPa, preferably 1,100 to 20,000 hPa, more preferably 1,300 to 5,000 hPa.

When the polymerization according to step b) is carried out as a slurry process, the solids content of the suspension in step b) is preferably in the range of 1 to 45 wt%, more preferably 3 to 40 wt%, even more preferably 15 to 45 wt%. 40% wt.

As used herein, the expressions “solids content” or “solids level” refer to the weight percentage of isoolefin polymer in the medium containing the produced isoolefin polymer, organic diluent, and optionally residual monomer(s) obtained according to step b).

In one embodiment, the interaction time in step b) is between 2 minutes. up to 2 hours, preferably from 10 minutes. up to 1 hour and more preferably from 20 to 45 minutes.

The process can be carried out batchwise or continuously. When a continuous reaction occurs, the above reaction time is equal to the average residence time.

In one embodiment, the reaction is stopped with quenching agents, for example, 1 wt%. a solution of sodium hydroxide in water, methanol or ethanol.

In another embodiment, the reaction is quenched by contact with an aqueous medium in step ) which in one embodiment may have a pH value measured at 20° C. and 1013 hPa of 5 to 11, preferably 6 to 10, and more preferably 8 to 9 .

Adjustment of pH where necessary can be accomplished by adding acidic or alkaline compounds, which preferably do not contain polyvalent metal ions. Adjusting the pH to higher values is accomplished, for example, by adding sodium or potassium hydroxide.

In particular, for solution polymerization, the conversion usually stops after consumption of the monomer from 5% of the mass. up to 25% wt., preferably from 10% wt. up to 20% wt. from the initial amount of monomers used.

Monomer conversion can be monitored using online viscometry or spectral monitoring during polymerization.

In one embodiment, in optional step c), in particular where step b) is carried out as a suspension process, the medium containing the product obtained in step b) is brought into contact with an aqueous medium, removing at least part of the organic diluent and to the extent that it is present in the medium, removing at least partially the residual monomer and carbon dioxide to obtain an aqueous suspension containing the isoolefin polymer in the form of fine particles, often called crumb rubber. The contact may be carried out in any suitable vessel and may be carried out periodically or continuously, the continuous method being preferred. In industry, such contact is usually carried out in a stripper, flash drum or any other vessel known for separating liquid and vapor.

To remove organic diluent and optionally monomers, other types of distillation can also be used to sequentially or simultaneously remove residual monomers and organic diluent to the desired extent. Distillation processes for the purpose of separating liquids with different boiling points are well known in the art and are described, for example, in the Encyclopedia of Chemical Technology, Kirk Othmer, 4th Edition, pp. 8-311, which is incorporated herein by reference. Typically, unreacted monomers and diluent can be reused separately or together in step a) of the process of the invention.

The pressure in optional step c) and in one embodiment the stripper or flash drum depends on the organic diluent and monomers used in step b).

The temperature in optional step c) is selected such that it is sufficient to at least partially remove the organic diluent, and to the extent that residual monomers are still present.

The organic diluent and/or monomer(s) removed in step c) can be reused again in steps a) and/or b).

In one embodiment, the temperature is from 10 to 100°C, preferably from 50 to 100°C, more preferably from 60 to 95°C, and even more preferably from 75 to 95°C.

In the case of step b) being carried out as a solution polymerization, after contact with water, the organic diluent is evaporated and the isoolefin polymer forms discrete particles suspended in the aqueous suspension.

In a further optional step d), the isoolefin polymer contained in the aqueous suspension obtained according to step c) can be isolated to produce an isoolefin polymer.

The separation can be accomplished by flotation, centrifugation, filtration, dewatering in a dewatering extruder, or any other methods known to those skilled in the art to separate solids from liquids.

In a further optional step e), the isoolefin polymer particles produced in step d) are dried, preferably to a residual volatile content of 7000 ppm or less, preferably 5000 ppm or less, even more preferably 4000 ppm or less, in another embodiment, 2000 ppm or less, preferably 1000 ppm or less.

As used herein, the term "volatile matter" refers to compounds having a boiling point below 250°C, preferably 200°C or less at standard pressure and includes water as well as remaining organic diluents.

Drying can be accomplished using conventional means known to those skilled in the art, which include drying on a heated mesh conveyor belt or in an extruder.

It has surprisingly been found that the isoolefin polymers produced according to the invention, in particular when isobutene and isoprene, commonly referred to as butyl rubber, are used as monomers, exhibit a unique microstructure.

If isoprene is incorporated into an isobutene backbone, this incorporation occurs primarily in two different ways and therefore results in two different structures. One structure is the so-called 1,4-isoprene structure

1,4-isoprene

The other structure is a branched structure

branched

A suitable method for differentiating these structures is nuclear magnetic resonance (NMR) spectroscopy. The proton NMR spectrum contains peaks that can be assigned to each of the above structures. Integrating the area of these peaks gives results that can be converted into mole percentages of each structure.

A maximum content of 1,4-isoprene is desirable as this allows easier curing of the isoolefin polymer or other chemical modifications such as halogenation to chlorobutyl rubber and bromobutyl rubber.

However, the typical molar ratio for the 1,4-isoprene structure and the branched structure of known and commercially available butyl rubbers is from 8.0 to 12.5. Surprisingly, this ratio for the butyl rubber produced according to the process described above is from 14.0 to 20.0, preferably from 14.0 to 17.0, and is therefore shifted into a more desirable range relative to what is currently known.

A further unexpected effect of the method according to the invention is that the formation of undesirable by-products is minimized.

Regardless of whether the polymerization is carried out in a suspension or solution manner, the cyclic oligomers of 1-isopropenyl-2,2,4,4-tetramethylcyclohexane, hereinafter designated C13, and 1,1,5,5-tetramethyl-2-(1 -methylethenyl)-3-(2,2,4-trimethylpentyl)cyclohexane, hereinafter referred to as C21, are produced as a by-product and remain in butyl rubber in amounts ranging from 1000 to 2500 ppm depending on the commercial source.

C13 C21

These cyclic oligomers are undesirable for certain applications, such as pharmaceutical closures, closures, blood collection vessel stoppers, medical devices, and food products due to the potential for such cyclic oligomers to migrate into/on the pharmaceutical or food product and then affect or interact with product and/or be administered to a patient. Therefore, reducing the levels of cyclic oligomers in butyl rubber is highly desirable, particularly when subsequent halogenation is contemplated, since halogenated oligomers are of even greater concern due to their reactivity.

It has been found that in the process according to the invention, in particular after performing step c) or optionally also step d), the sum of C13 and C21 in the butyl rubber is usually less than 800 ppm, preferably from 50 to 800 ppm and even more preferably from 200 to 700 ppm

The C13 content of butyl rubber is typically less than 350 ppm, preferably 20 to 300 ppm, and even more preferably 50 to 300 ppm

The C21 content of butyl rubber is typically less than 450 ppm, preferably 30 to 450 ppm, and even more preferably 50 to 400 ppm

The weight ratio of C21 to C13 in butyl rubber is usually from 0.9 to 2.0, preferably from 1.2 to 2.0, while for known butyl rubbers from various commercial sources, the ratio is usually from 2.3 to 4.0.

According to the invention, preferred butyl rubbers are those already covered in the above preparation paragraph and include butyl rubbers containing repeating units, isobutene derivatives and isoprene derivatives.

Typically, the butyl rubber according to the invention has an isoprene content of 0.1 mol%. or more, preferably from 0.1 mol%. up to 15 mol%, in another embodiment 0.5 mol%. or more, preferably from 0.5 mol%. up to 10 mol%, in another embodiment 0.7 mol%. or more, preferably from 0.7 to 8.5 mole%, in particular from 0.8 to 2.0, or from 1.5 to 2.5 mole%, or from 2.5 to 4.5% mol., or from 4.5 to 8.5% mol.

In another embodiment, the isoprene content of the butyl rubbers of the invention is 0.001 mol%. or more, preferably from 0.001 mol%. up to 3 mol%, preferably from 0.8 mol%. up to 3% mol.

In one embodiment, the weight average molecular weight of the butyl rubber of the invention is from 10 to 2000 kg/mol, preferably from 20 to 1000 kg/mol, more preferably from 50 to 1000 kg/mol, even more preferably from 200 to 800 kg/mol, still more preferably 375 to 550 kg/mol and most preferably 400 to 500 kg/mol. Molecular weights are obtained by gel permeation chromatography in tetrahydrofuran (THF) solution using polystyrene molecular weight standards unless otherwise stated.

In one embodiment, the polydispersity of the butyl rubber of the invention is in the range of 1.5 to 4.5, as determined by the ratio of weight average molecular weight to number average molecular weight, as determined by gel permeation chromatography, preferably in the range of 2.5 to 3.5.

Butyl rubber is, for example, according to the invention and typically has a Mooney viscosity of at least 10 (ML 1+8 at 125°C, ASTM D 1646), preferably from 10 to 80, more preferably from 20 to 80 and even more preferably from 25 to 60 (ML 1+8 at 125°C, ASTM D 1646).

In one embodiment, the butyl rubber of the invention has an ash content, measured in accordance with ASTM D5667, of 0.25% by weight. or less, preferably 0.15 wt%. or less, more preferably 0.10 wt%. or less and even more preferably 0.05 wt%. or less.

Rubber Products

One or more butyl rubbers according to the invention can be mixed either with each other or additionally or alternatively with at least one secondary rubber, which is preferably selected from the group consisting of natural rubber (NR), epoxidized natural rubber (ENR), polyisoprene rubber, polyisobutylene rubber, poly(styrene butadiene) rubber (SBR), chloroprene rubber (CR), polybutadiene rubber (BR), perfluoroelastomer (FFKM/FFPM), ethylene acetate (EVA) rubber, ethylene acrylate rubber, polysulfide rubber (TR), poly( Isoprene Butadiene Rubber (IBR), Styrene Isoprene Butadiene Rubber (SIBR), Ethylene Propylene Rubber (EPR), M Class Ethylene Propylene Diene Rubber (EPDM), Polyphenylene Sulfide, Nitrile Butadiene Rubber (NBR), hydrogenated nitrile butadiene rubber (HNBR), propylene oxide polymers, star-branched butyl rubber and halogenated star-branched butyl rubber, butyl rubbers which are not the subject of the present invention, i.e. have varying levels of polyvalent metal ions or purities, brominated butyl rubber and chlorinated butyl rubber, star-branched polyisobutylene rubber, star-branched brominated butyl (polyisobutylene/isoprene copolymer) rubber; poly(isobutylene-co-p-methylstyrene) and halogenated poly(isobutylene-co-p-methylstyrene), halogenated poly(isobutylene-co-isoprene-co-p-methylstyrene), poly(isobutylene-co-isoprene-co-styrene) ), halogenated poly(isobutylene-co-isoprene-co-styrene), poly(isobutylene-co-isoprene-co-α-methylstyrene), halogenated poly(isobutylene-isoprene-α-methylstyrene). One or more butyl rubbers according to the invention, or mixtures thereof with secondary rubbers described above, can be additionally or alternatively mixed, for example, simultaneously or separately, with at least one thermoplastic polymer, which is preferably selected from the group consisting of polyurethane (PU), polyacrylic esters (ACM, PMMA), thermoplastic poly(ester)urethane (AU), thermoplastic poly(ether)urethane (EU), perfluoroalkoxyalkane (PFA) and polytetrafluoroethylene (PTFE).

The butyl rubbers of the invention, or mixtures thereof with the disclosed secondary rubbers and/or thermoplastic polymers, may or may not contain other components commonly used in the rubber industry, such as fillers and hardeners. They are typically formulated with one or more fillers and are collectively referred to hereinafter as rubber products.

Applications

The rubber products of the present invention are very useful in a wide variety of applications. The low degree of gas permeability, sites of unsaturation that can serve as crosslinking sites, sites of curing or post-polymerization modification, and low levels of interfering additives are the reason for the greatest use of these rubber products.

Thus, the invention also covers the use of the rubber products of this invention for inner casings, cylinders, tubes, air bags, air springs, air cylinders, battery bags, hoses, conveyor belts and pharmaceutical caps. The invention also covers the above-mentioned articles containing the rubber products of the present invention, whether cured or uncured.

The rubber products of the present invention further exhibit high damping and a uniquely wide range of damping and damping, both in temperature and frequency.

Thus, the invention also covers the use of the rubber products of the present invention in automobile suspension bumpers, automobile exhaust brackets, body supports and shoe soles.

The rubber products of the present invention are also suitable for tire sidewalls and treads. In the sidewalls, the characteristics of butyl rubber provide good ozone resistance, crack growth and appearance.

The rubber products of the present invention can be molded into the desired product before curing. Articles containing the cured butyl rubber of the present invention include, for example, belts, hoses, shoe soles, gaskets, O-rings, wires/cables, membranes, rollers, cylinders (eg, vulcanization cylinders), tire liners, tire treads, shock absorbers , equipment fastenings, balloons, balls, golf balls, protective clothing, medical tubing, storage tank lining, electrical insulation, bearings, pharmaceutical stoppers, adhesives, containers such as bottle, bag, storage tank, etc.; container seal or lid; sealant or sealant, such as gasket or potting; a material handling device such as an auger or conveyor belt; drive belts, cooling tower; metal working devices or any devices that come into contact with metal working fluids; engine components such as fuel lines, fuel filters, fuel tanks, gaskets, seals, etc.; membranes for filtering liquids or sealing tanks.

Hereinafter, the invention is further explained by way of examples, without being limited thereto.

Experimental part:

X.1 Batch polymerization

Polymerization was carried out in a MBraun MB-200G glove box equipped with a pentane cooling bath, a reactor, and a bath temperature recorder. Isoprene (>99%) was purchased from Sigma-Aldrich and further purified by drying over CaH ₂ for 24 hours. under a nitrogen atmosphere, and distilled over CaH ₂ under nitrogen into an oven-dried receiver flask before being transferred to a glove box where it was stored at -2°C until use. Methyl tert-butyl ether (MTBE, anhydrous, 99.8%) was dried over 3A molecular sieves before use. AlCl ₃ (99.99%) was purchased from Sigma Aldrich and used as received.

Example 1: preparation of AlCl initiator solution ₃

Each day, a fresh AlCl ₃ initiator solution was prepared and used for all experiments performed during that day. In a glove box, AlCl ₃ (0.30 g, 2.25 mmol) was loaded into a 100 ml Erlenmeyer flask, dissolved in MeCl (100 ml) and cooled to -30°C. The solution was stirred using a mechanical stirrer at 450 rpm. for 30 min at -30°C. Stirring was stopped, the flask was sealed and the solution was cooled to -95°C until use.

Example 2: General Suspension Polymerization Procedure

A 500 mL stainless steel beaker equipped with a temperature probe was placed in a pentane bath cooled to -95°C and pre-cooled methyl chloride (MeCl, 180 mL) was charged. Isobutene (20 mL, 14.24 g, 25.0 mmol) was condensed as a liquid into a pre-cooled graduated cylinder and transferred to the reaction vessel. Isoprene (0.8 mL, 0.54 g, 7.92 mmol) was pipetted into the reaction mixture. The solution was mechanically stirred at 800 rpm. until the temperature stabilizes. Transfer the pre-prepared solution of AlCl ₃ initiator (3 ml, 0.0090 g, 0.0675 mmol) into the reaction mixture using a pre-cooled pipette, initiating the reaction. The polymerization mixture was stirred for 5 minutes. at 800 rpm unless otherwise stated. The polymerization was stopped by adding ethanol NaOH solution (1.0 mL, 1 wt%, 0.01 mmol). The polymer suspension was removed from the glove box, diluted with hexane (approximately 300 ml) and antioxidant (1.0 ml, 1 wt% Irganox 1076 in hexane) and left to stand in a fume hood overnight to remove volatiles. The polymer was coagulated with ethanol (approximately 500-1000 ml) and the resulting polymer (7.9800 g, 53.7%) was collected and dried in a vacuum oven at 60°C for 48 hours. The degree of conversion was determined by gravimetric analysis. The initiator efficiency was calculated at 887 g polymer/g AlCl ₃ . The results are shown in Table 1.

Table 1: Suspension polymerization without MTBE

Mode
(for comparison) Conversion (%) Efficiency
(g polymer/g AlCl ₃ ) 1 41.3 681 2 52.2 862 3 50.7 837 4 48.2 796 5 53.8 889 6 57.9 957 7 36.9 609 8 36.6 813 9 36.9 819 10 38.8 861 eleven 30.8 683 12 68.0 631 13 69.6 646 14 57.4 836 15 54.4 792 16 74.4 614 17 72.6 599

Example 3: Preparation of MTBE solution

A 100 mL Erlenmeyer flask kept in a pentane bath cooled to -95°C was charged with pre-cooled MeCl (100 mL). Methyl tert-butyl ether (MTBE, 5 μL, 0.0037 g, 0.042 mmol) was transferred into the flask using a micropipette. The contents of the flask were stirred to disperse the MTBE in MeCl, the flask was then sealed and the solution was stored at -95°C until use.

Example 4: Suspension polymerization with MTBE added to the reactor

A 500 mL stainless steel beaker equipped with a temperature probe was placed in a pentane bath cooled to -95°C and pre-cooled MeCl (180 mL) was charged. Isobutene (20 mL, 14.24 g, 25.0 mmol) was condensed as a liquid into a pre-cooled graduated cylinder and transferred to the reaction vessel. Transfer isoprene (0.8 mL, 0.54 g, 7.92 mmol) to the reaction mixture using a pipette. A portion of the pre-prepared MTBE solution was transferred into the reaction vessel using a pre-cooled pipette. The amounts of MTBE added are shown in Table 2. The solution was mechanically stirred at 800 rpm. A pre-prepared solution of AlCl ₃ initiator (3 ml, 0.0090 g, 0.0675 mmol) was transferred into the reaction mixture using a pre-cooled pipette, initiating the reaction. The polymerization mixture was stirred for 5 minutes. at 800 rpm unless otherwise stated. The polymerization was stopped by adding ethanol NaOH solution (1.0 mL, 1 wt%, 0.01 mmol). The polymer suspension was removed from the glove box, dissolved in hexane (approximately 300 ml) and antioxidant (1.0 ml, 1 wt% Irganox 1076 in hexane) and left to stand in a fume hood overnight to remove volatiles. The polymer was coagulated with ethanol (approximately 500-1000 ml) and the resulting polymer was collected and dried in a vacuum oven at 60°C for 48 hours. The degree of conversion was determined by gravimetric analysis. The results are shown in Table 2.

Table 2: Suspension polymerization when adding MTBE to the reactor

Mode MTBE (µl) MTBE(g) MTBE
(mol) Molar ratio MTBE:AlCl ₃ Conversion (%) Efficiency (g polymer/g AlCl ₃ ) 18 0.025 0.00002 2.0998E-07 0.005 70.8 1062 19 0.050 0.00004 4.1997E-07 0.01 79.1 1187 20 0.150 0.00011 1.2599E-06 0.02 83.8 1256 21 0.300 0.00022 2.5198E-06 0.03 84.6 1268 22 0.450 0.00033 3.7797E-06 0.05 84.9 1274 23 0.600 0.00044 5.0396E-06 0.07 87.5 1312 24 0.750 0.00056 6.2995E-06 0.08 84.8 1272 25 1,000 0.00074 8.3993E-06 0.11 85.4 1281

Example 5: Suspension polymerization with addition of MTBE to initiator

A portion of the pre-prepared AlCl ₃ initiator solution (20 ml, 0.06 g, 0.45 mmol) was transferred to a new 100 ml Erlenmeyer flask and kept at -95°C in a cooled pentane bath. Methyl tert-butyl ether (MTBE, 4 μL, 0.0029 g, 0.034 mmol) was transferred into the flask using a micropipette. The contents of the flask were stirred to disperse the MTBE in the initiator solution, then the flask was sealed and the solution was stored at -95°C until use.

A 500 mL stainless steel beaker equipped with a temperature probe was placed in a pentane bath cooled to -95°C and loaded with pre-cooled methyl chloride (MeCl, 180 mL). Isobutene (20 mL, 14.24 g, 25.0 mmol) was condensed as a liquid into a pre-cooled graduated cylinder and transferred to the reaction vessel. Transfer isoprene (0.8 mL, 0.54 g, 7.92 mmol) to the reaction mixture using a pipette. The solution was mechanically stirred at 800 rpm until the temperature stabilized. A pre-prepared solution of AlCl ₃ initiator containing MTBE (3 ml, AlCl ₃ = 0.0090 g, 0.0675 mmol; MTBE = 0.0004 g, 0.0050 mmol) was transferred into the reaction mixture using a pre-cooled pipette, initiating the reaction . The polymerization mixture was stirred for 5 minutes. at 800 rpm unless otherwise stated. The polymerization was stopped by adding ethanol NaOH solution (1.0 mL, 1 wt%, 0.01 mmol). The polymer suspension was removed from the glove box, diluted with hexane (approximately 300 ml) and antioxidant (1.0 ml, 1 wt% Irganox 1076 in hexane) and left to stand in a fume hood overnight to remove volatiles. The polymer was coagulated with ethanol (approximately 500-1000 ml) and the resulting polymer (12.3520 g, 83.2%) was collected and dried in a vacuum oven at 60°C for 48 hours. The degree of conversion was determined by gravimetric analysis. Initiator efficiency was calculated at 1287 g polymer/g AlCl ₃ . The results are shown in Table 3.

Table 3: Suspension polymerization with initiator system containing MTBE

Mode MTBE (µl) MTBE(g) MTBE (mol) Molar ratio
MTBE:AlCl ₃ Conversion (%) Efficiency (g polymer/g AlCl ₃ ) Mw (g/mol) 26 0.050 0.00004 4.1997E-07 0.01 81.8 1227 626259 27 0.150 0.00011 1.2599E-06 0.02 85.1 1276 563055 28 0.300 0.00022 2.5198E-06 0.03 81.5 1222 463035 29 0.450 0.00033 3.7797E-06 0.05 86.2 1293 463696 thirty 0.600 0.00044 5.0396E-06 0.07 83.7 1256 448724 31 0.750 0.00056 6.2995E-06 0.08 81.4 1222 423516 32 1,000 0.00074 8.3993E-06 0.11 83.3 1249 439745 33 1.688 0.00125 1.4174E-05 0.19 75.1 1093 424494

X.2 Polymer analysis

Polymerization was monitored using a digital thermocouple to monitor temperature changes. NMR spectral analysis was carried out on a Bruker 500 MHz NMR spectrometer using solutions of the polymer in CDCl ₃ with concentrations of about 5 mg/ml. A delay of 10 seconds was applied. for 32 accumulations with 90° pulse. Chemical shifts in ^1H spectra were expressed in ppm. relative to tetramethylsilane (TMS) (δ=0).

Further experiments were carried out to demonstrate the necessary structural characteristics to obtain the desired benefits. Experiments were carried out as described above, but with variation in the ether component. It has been found that a tertiary alkyl group is required to realize maximum efficiency of the initiator. The results on the effectiveness of the initiator are shown in Table 4:

Table 4: Suspension polymerization using an initiator system containing various ethers

Ether g polymer/g AlCl ₃ Control (off-air) 876 Methyl tert-butyl ether (MTBE) 1264 Ethyl tert-butyl ether (ETBE) 1283 Methyl sec-butyl ether (MSBE) 847 Dipropyl Ether (DPE) 954 Methyl tert-amyl ether (MTAE) 1338

X.3 - Continuous polymerization

Example 6:

The following experiments were performed to demonstrate the ability of tertiary alkyl ethers to be beneficial in continuous cationic polymerization to isobutylene-isoprene rubber.

A polymerization feed (Stream 1) was prepared comprising 62% methyl chloride, 37% isobutylene, 1% isoprene and 10 ppm MTBE and cooled to approximately -100°C. Separately, a solution of the initiator (stream 2) of aluminum trichloride (~0.2% wt) and water (traces) in methyl chloride was prepared and also cooled to approximately -100°C. Streams 1 and 2 were continuously fed into a stainless steel reaction vessel, which was also cooled to -100°, said vessel being equipped with a stirrer and a temperature sensor. After contact of the two streams in the vessel with stirring, the monomers reacted to form isobutylene-isoprene rubber with a yield of 60 to 90%, defined as the weight of the polymer produced relative to the weight of the isobutene introduced. The contents of the stirred reaction vessel were allowed to flow continuously into a second vessel where the remaining active initiator molecules from Stream 2 were neutralized with sodium hydroxide. The ratio between streams 1 and 2 was continuously adjusted in response to changes in temperature within the cooled reaction vessel, maintaining the temperature from -100°C to -85°C. Samples were periodically taken from the second vessel for further analysis. After flow 1 was exhausted, the experiment was stopped and the neutralized samples were degassed and analyzed.

The control experiment was performed as described above, but in the absence of MTBE.

It was thus demonstrated that in the presence of MTBE, isoprene-isobutylene elastomer can be continuously produced using a fraction of the initiator solution normally required for polymer formation. In the table below this is expressed in grams of polymer produced per gram of _AlCl3 :

Sample g polymer/g AlCl ₃ T1 control 1386 T2 control 1245 T3 control 1306 MTBE T1 3381 MTBE T2 3553 MTBE T3 3915

Analysis of samples collected from the MTBE and control experiments revealed a number of clear benefits to the products obtained using MTBE. These benefits include a reduction in product polydispersity, a reduction in by-product cyclic oligomers, and a reduction in the non-reactive "branched" component of the product's intrachain unsaturation. The results are presented in tables 5 to 7.

Table 5:

Reduced molecular weight distribution determined using the polydispersity index

Sample Mn Mw Polydispersity Control 1 167433 654448 3.91 Control 2 146152 641169 4.39 Control 3 159201 656921 4.13 MTBE 1 227448 675115 2.97 MTBE 2 241128 613962 2.55 MTBE 3 204572 555522 2.72 MTBE 4 182767 515347 2.82 MTBE 5 170178 491620 2.89 MTBE 6 175831 488686 2.78 MTBE 7 176687 507678 2.87

Table 6:

Reducing the amount of C ₁₃ H ₂₄ and C ₂₁ H ₄₀ oligomers and the ratio of C ₂₁ /C ₁₃ oligomers determined by gas chromatography

Sample C ₁₃ H ₂₄ C ₂₁ H ₄₀ Ratio C ₂₁ / C ₁₃ Control 1 485 1423 2.93 Control 2 483 1523 3.15 Control 3 481 1404 2.92 MTBE 1 218 365 1.67 MTBE 2 224 275 1.23 MTBE 3 237 321 1.36 MTBE 4 278 421 1.51 MTBE 5 272 444 1.64 MTBE 6 276 452 1.64 MTBE 7 240 439 1.82

Table 7:

Reducing the relative contribution of branched unsaturation (non-reactive) to total unsaturation

Sample %
1,4-isoprene %
Branched %
General unsaturated %
Branch/common Control 1 1.61 0.13 1.74 7.5 Control 2 1.59 0.13 1.72 7.6 Control 3 1.62 0.13 1.74 7.5 MTBE 1 1.55 0.10 1.65 6.1 MTBE 2 1.60 0.10 1.69 5.9 MTBE 3 1.70 0.11 1.81 6.1 MTBE 4 1.69 0.10 1.79 5.6 MTBE 5 1.71 0.12 1.82 6.6 MTBE 6 1.70 0.12 1.81 6.6 MTBE 7 1.66 0.11 1.77 6.2

Claims (19)

1. A method for producing isoolefin polymers, the method comprising the following stages: a) providing a reaction medium containing a single organic diluent, an isoolefin monomer, a multiolefin monomer, and an initiator system containing at least one aluminum compound and, at least one tertiary ether, where the molar ratio of the tertiary ether to the sum of aluminum atoms of the aluminum compounds used is from 0.001 to 0.200, And b) polymerizing the monomers in a reaction medium in the presence of a given initiator system at a temperature in the range of -100°C to -60°C to form a resultant medium containing an isoolefin polymer, an organic diluent and optionally residual monomer(s), wherein the isoolefin polymer contains butyl rubber having a molar ratio of 1,4-isoprene to branched structure from 14.0 to 20.0, preferably from 14.0 to 17.0. 2. The method according to claim 1, wherein the isoolefin is isobutene. 3. The method according to claim 1, where the multiolefins are selected from the group consisting of isoprene, butadiene, 2-methylbutadiene, 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 or 1-vinylcyclohexadiene or mixtures of the substances mentioned above. 4. The method according to claim 3, wherein the multiolefin is isoprene. 5. The method of claim 1, wherein the reaction medium further contains monomers that copolymerize with at least one isoolefin and are neither isoolefins nor multiolefins. 6. The method of claim 1, wherein the diluents include chlorohydrocarbon(s), such as methyl chloride, methylene chloride or ethyl chloride; hydrofluorocarbons represented by the formula: C _x H _y F _z where x is an integer from 1 to 40, and y and z are integers and are equal to at least one; unsaturated hydrofluorocarbons; hydrocarbons, preferably alkanes. 7. The method of claim 1, wherein the aluminum compounds are compounds represented by the formula MX ₃ where M is an aluminum atom and X is a halogen atom, preferably aluminum trichloride, or compounds represented by the formula MR _(m) X _(3-m) where M is an aluminum atom and X is a halogen atom, R is a monovalent hydrocarbon radical selected from the group consisting of C ₁ -C ₁₂ alkyl and C ₇ -C ₁₄ alkylaryl radicals; and m is equal to one or two. 8. The method of claim 1, wherein the tertiary ethers are methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), methyl tert-amyl ether (MTAE) and phenyl tert-butyl ether ( PTBE) or mixtures thereof, with methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), methyl tert-amyl ether (MTAE) or mixtures thereof being preferred, and methyl tert-butyl ether (MTAE) or mixtures thereof being even more preferred. butyl ether (MTBE). 9. Butyl rubber for the manufacture of rubber products, obtained by the method according to any one of paragraphs. 1-8, having a molar ratio of 1,4-isoprene to branched structure from 14.0 to 20.0, preferably from 14.0 to 17.0. 10. Butyl rubber for the manufacture of rubber products, obtained by the method according to any one of paragraphs. 1-8, having a mass ratio of 1,1,5,5-tetramethyl-2-(1-methylethenyl)-3-(2,2,4-trimethylpentyl)cyclohexane (C ₂₁ ) to 1-isopropenyl-2,2, 4,4-tetramethylcyclohexane (C ₁₃ ) in butyl rubber from 0.9 to 2.0, preferably from 1.2 to 2.0. 11. Butyl rubber according to claim 9 or 10, having the sum of 1,1,5,5-tetramethyl-2-(1-methylethenyl)-3-(2,2,4-trimethylpentyl)cyclohexane (C ₂₁ ) and 1-isopropenyl -2,2,4,4-tetramethylcyclohexane (C ₁₃ ) in butyl rubber less than 800 ppm, preferably from 50 to 800 ppm and even more preferably from 200 to 700 ppm. 12. Butyl rubber of claim 9 or 10, having a polydispersity of 1.5 to 4.5, determined from the ratio of weight average molecular weight to number average molecular weight, as measured by gel permeation chromatography. 13. A mixture for the manufacture of rubber products containing butyl rubber according to any one of paragraphs. 9-12 and at least one secondary rubber.