DE2815289A1 - GEL-FREE POLYMER AND THIS VULCANIZABLE MOLDING COMPOUND - Google Patents

Description

The invention relates to new polymer products which are gel-free copolymers of isobutylene and isoprene and Terpolymers of isobutylene-isoprene-cyclopentadiene with a number average molecular weight, by means of membrane osmometry measured, is at least 90,000 and a proportion of double bonds of at least 5 mol%. The invention relates to also a process for making these essentially gel-free copolymers.

You have to, when using the copolymers and terpolymers of the invention wants to receive, carry out the reaction at temperatures below -1OO ° C. To achieve the desired The number average molecular weight of a substantially gel-free polymer is required to polymerize homogeneously. This is achieved if the reaction is carried out in a carrier medium which, at the reaction temperature, is a solvent for the copolymer is performing. The carrier medium is predominantly the monomers to be polymerized in combination with an inert cosolvent or mixtures of inert cosolvents plus catalyst solvents.

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The copolymers of the invention are made from an isoolefin and a straight chain conjugated hydrocarbon multiolefin or a cyclic conjugated hydrocarbon multiolefin educated.

The terpolymers of the invention are made from an isoolefin and two conjugated hydrocarbon multiolefins are formed, and the two multiolefins can be either a straight-chain multiolefin and a cyclic multiolefin or two cyclic multiolefins.

Isoolefins suitable for the purposes of the present invention are preferably hydrocarbon monomers having from 4 to 10 carbon atoms. Examples of such isoolefins are isobutylene, 2-methyl-1-butene, 3-methyl-1-butene, 4-methyl-1-pentene and ß-pinene. Isobutylene is preferably present as the isoolefin.

Multiolefins useful for the purposes of the present invention are conjugated hydrocarbon multiolefins with 5 to 14 Carbon atoms, particularly preferably conjugated diolefins having 5 to 9 carbon atoms are present as multiolefins. Examples of such multiolefins are isoprene, piperylene, 2,3-dimethylbutadiene, 2,5-dimethylhexadiene-2,4-ene, cyclopentadiene, Cyclohexadiene, methylcyclopentadiene, fulvene and the like and mixtures thereof.

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When carrying out the process according to the invention, it is essential that the cosolvent is present in an amount of at least 5% by volume, but not more than 40% by volume, based on the total reaction mixture. It is expedient to use 5 to 30% by volume of solvent, in particular 0.5 to 25% by weight and particularly preferably 10 to 20% by weight, that is to say 15% by volume
Solvent used. The term "total reaction mixture" is used in the present description and claims to denote the total amount of monomers plus cosolvent.

The optimum amount of cosolvent to be used corresponds to the minimum amount required to prevent the To prevent the reactor or gelatinization. If you use too little cosolvent, the reactor can become dirty or gel the product. If one uses too much cosolvent, a polymer product with an undesirably low one results Number average molecular weight.

In the present context, it is useful to define the volume percentages for the inert cosolvent
as the volume calculated based on the volume of the monomer at -78 C (dry ice temperature), while the volume of the cosolvent is determined at 25 C. The calculated volume percentages for the cosolvent are relative to

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Changes in volume and cooling of the solvent to reaction conditions uncorrected.

The minimum amount of a given cosolvent required to produce gel-free polymers is a function this cosolvent, the conjugated multiolefin used and the polymerization temperature. If you look at the mixture composition of monomers and the cosolvent to be used, the required The minimum amount of cosolvent can simply be determined by preliminary experiments in which the polymerization is carried out with different Performs amounts of cosolvent. The minimum amount of cosolvent required is the amount that you can use required to maintain a homogeneous system, i.e. the amount that is required to cause precipitation to prevent polymer during polymerization.

The term "cosolvent" is used in the specification and claims for the inert solvent which together serves with the monomer charge as a carrier medium for the reaction. The cosolvent and monomers must be soluble in each other and the mixture of monomers plus cosolvent has to be at the Poiymerisation Temp Be solvent for the copolymer. The term "inert" means that the cosolvent neither interacts with the catalyst

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reacts or intervenes in the polymerization reaction in any other way. The cosolvent is allowed in its molecular structure do not contain any substituents that could co-react during the polymerization reaction. Suitable cosolvents are aliphatic hydrocarbons. Preferred cosolvents are paraffinic hydrocarbons and carbon disulfide. Useful as a paraffinic hydrocarbon solvent are hydrocarbons with 5 to 10 carbon atoms, in particular advantageously hydrocarbons with 5 to 8 carbon atoms. Examples of the hydrocarbon solvents are Pentane, isopentane, methylpentane, hexane, cyclohexane, methylcyclohexane, Dimethylcyclohexane, heptane, isooctane, 1, 2, 3,3-tetramethy ^ eXane, Tetramethy ^ yc ^ heXan and the like. As a general rule any paraffin that is liquid under the polymerization conditions can be used, regardless of whether it is a normal, branched or cyclic paraffin. The term "paraffin" is used in the description and the claims for the designation of normal paraffins, cycloparaffins and branched paraffins and mixtures thereof are used. If a cyclodiene is used as the diene Preferred cosolvents that contain cycloparaffins.

Since some of the monomers serve as a solution system for the polymer, the degree of conversion during the polymerization must not be be so large that the copolymer as a result of depletion of solution

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is medium. The degree of implementation is preferably 2 to 30%, in particular 3 to 15% and especially preferably 5 to 13%, for example 10%.

For the purposes according to the invention, an aluminum halide or a hydrocarbyl aluminum dihalide can serve as a catalyst. When an aluminum halide is used, it must be in the form of a homogeneous solution or an ultrafine dispersion of the catalyst particles, i.e. colloidal dispersion. It is therefore necessary to disperse or dissolve the aluminum halide catalyst in a suitable catalyst solvent or mixture of solvents. The solvent for the aluminum halide catalyst must be a polar solvent. Examples of suitable aluminum halides are AlCl ₃ and AlBr ₃ . The preferred aluminum halide catalyst is aluminum chloride. The term "polar solvent" is used in the description and the claims to denote non-aromatic organic solvents with a dielectric constant at 25 ° C. of at least 4, preferably 4 to 20, in particular 6 to 17 and particularly preferably 9 to 13. However, these polar solvents must not contain sulfur, oxygen, phosphorus or nitrogen in their molecule, since compounds with these elements can react with the catalyst or otherwise deactivate it.

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The preferred polar solvents are inert halogenated aliphatic hydrocarbons. Halogenated paraffinic hydrocarbons and vinyl or vinylidene halides are particularly useful, and the primarily or secondary chlorinated paraffinic hydrocarbons are particularly preferred. The halogenated hydrocarbons are expediently paraffinic hydrocarbons with 1 to 5 carbon atoms, especially a C ₁ -C ₂ paraffin. The ratio of carbon atoms to halogen atoms in the polar solvent is advantageously 5 or less. Chlorine is advantageously present as halogen.

Examples of such polar organic solvents are methyl chloride, ethyl chloride, propyl chloride, methyl bromide, Ethyl bromide, chloroform, methylene chloride, vinyl chloride, vinylidene chloride, dichloroethylene and the like. Methyl chloride or ethyl chloride are preferred as polar solvents. In general, any inert halogenated organic Compound that is normally liquid under polymerization conditions and has a dielectric constant of at least 4.0 can be used.

When carrying out the process according to the invention, it is essential that the aluminum halide catalyst in the polar organic solvent is brought into solution,

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before the catalyst is introduced into the reaction medium. When the polar organic solvent is brought together with the reaction medium and only then the aluminum halide catalyst admits, it is not possible to obtain polymers according to the invention with the specified high Mn and the high proportion of double bonds to manufacture.

When the term "solution" is used with reference to the polar organic solvent / aluminum halide systems, Both real solutions and colloidal dispersions are understood by this, because these are next to each other in the same System can exist.

In the aluminum halide / polar solvent catalyst system, from 0.01 to 2% by weight, expediently from 0.05 to 1% by weight and in particular 0.1 to 0.8% by weight aluminum halide is present.

As previously mentioned, the catalyst can also be a hydrocarbyl aluminum dihalide. The hydrocarbyl group can be a straight chain containing 1 to 18 carbon atoms, be branched or cyclic group. Both cycloaliphatic and aromatic substituents can use the Form hydrocarbyl radical. Alkyl groups, especially lower alkyl groups, for example those with 1 to 4 carbon atoms,

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are preferred because they are generally readily available and economical. The halogen can be bromine or chlorine; chlorine is particularly useful. The term "dihalide" is used in the description and claims for dichloride or Dibromide used.

Examples of such hydrocarbyl aluminum dihalides are methyl aluminum dichloride, ethyl aluminum dichloride, isobutyl aluminum dichloride, Methyl aluminum dibromide, ethyl aluminum dibromide, benzyl aluminum dichloride, phenyl aluminum dichloride, Xylyl aluminum dichloride, toluyl aluminum dichloride, butyl aluminum dichloride, Hexyl aluminum dichloride, octyl aluminum dichloride, cyclohexyl aluminum dichloride, etc. The preferred Catalysts are methyl aluminum dichloride, ethyl aluminum dichloride and isobutyl aluminum dichloride.

The hydrocarbyl aluminum dihalide catalyst can be added as such or in solution. When a catalyst solvent is used, it is advantageous to use a liquid paraffinic solvent or a cycloparaffinic one Solvent. It is beneficial, although not essential, to use low freezing paraffins use. Methylcyclohexane is particularly advantageous because catalyst solutions have a concentration of about 1% at -120.degree don't freeze.

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The concentration of the catalyst is not critical. But overly dilute catalyst solutions are not desirable, since certain partial amounts of the catalyst can be deactivated by impurities. Very concentrated solutions are undesirable because at polymerization temperatures catalyst can be lost by freezing out of the solution.

When carrying out the polymerization for the preparation of the polymers according to the invention, the person skilled in the art will find that only catalytic amounts of catalyst solution are required. The volume ratio of monomer is preferably plus cosolvent to catalyst solution 100/1 to 9/1, appropriate 80/1 to 10/1 and in particular 40/1 to 20/1.

When carrying out the process according to the invention, it is important that the polymerization takes place in a homogeneous phase, without any precipitation of polymer occurring. Conventional slurry processes are for the production of the polymers of the invention with a high proportion of double bonds not usable since polymer precipitation in them by nature and as a result Gelation of the polymer takes place.

The amount of cosolvent that is required to make the reaction components for the polymerization and the polymerization product in solution during the entire polymerization time

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is a function of the multiolefin chosen for the polymerization and its concentration in the monomer charge. The polymerization temperature at which precipitation of the polymer can take place is in turn a function the amount and type of cosolvent and the particular copolymerized multiolefin.

The term "critical homogeneous polymerization temperature" is used in the present description and claims to denote the polymerization temperature can take place below the precipitation of the polymer if no cosolvent is present in the reaction mixture, that is, if only the monomer charge is used as the solvent for the reaction components and the reaction product is available.

Characterization of a polymer prepared by bulk polymerization, that is, without cosolvents, shows that polymers formed thereby have a low number average molecular weight (Mn). It is a common measure to lower the polymerization temperature in order to increase the Mn. If, however, one works without cosolvent, then the result achieved is not a larger Mn but gelation '.

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The gelation problem is eliminated by adding a cosolvent, which makes it possible to keep the polymerization temperature below the critical homogeneous polymerization temperature to lower. It has been found that a polymerization temperature below -100 C is required to achieve Mn values of at least 90,000 for the copolymers and terpolymers of the invention to reach. At least 5% by volume of inert solvent, based on the monomer charge, are required to carry out the polymerization in solution at such low temperatures to be able to.

In Fig. 1 of the accompanying drawings is the volume percentage of multiolefin (isoprene) in the monomer mixture (B #) as a puncture of the polymerization temperature, below the precipitation of the polymer takes place as a result of gelation in the absence of the cosolvent, applied. The curve illustrates the critical homogeneous polymerization temperatures for isobutylene-isoprene systems.

In the process according to the invention, isobutylene and isoprene are used in the same ratio in which they are present in the feed, incorporated into the copolymer. For example, if there is 15 volume percent isoprene in an isobutylene-isoprene monomer feed the polymer formed therefrom contains about 12.5 mol% of double bonds.

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The term "double bonds" or "multiolefin" is used used synonymously to indicate the amount of multiolefin built into the product. The composition of the copolymer (mol.% Double bond = mole percent diene content) is essentially the same as the feed composition for acyclic ones Serve such as isoprene and piperylene. However, when they are cyclic dienes such as cyclopentadiene these in the copolymer in significantly higher amounts, for example 3 to 4 times more, than are present in the feed.

In Fig. 2 of the accompanying drawing is illustrated that _t it is necessary to employ low polymerization temperatures. FIG. 2 shows the exponential decrease in the number average molecular weight with increasing temperature. It can be seen from Figure 3 that the selection of appropriate amounts of cosolvent is critical. If too little solvent is present, precipitation of the polymer occurs and corresponding fouling of the reactor or gelation occurs. If too much cosolvent is present, low molecular weight products will result. Further advantages of a low temperature and a suitable selection of a correspondingly low concentration of cosolvent are illustrated in FIGS. Figure 4 indicates that reactivity at low temperatures is favored (in addition to the benefit of the desired molecular weight). Fig. 5 shows that the catalyst efficiency is indicated by low concentration

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Cosolvent is improved (in addition to the benefit of the desired molecular weight).

For carrying out the method according to the invention, the Proceed as follows to determine the preferred reaction conditions of the person skilled in the art.

First, a suitable polymerization temperature below -100 ⁰ C is selected. Next, the desired composition of the feed, i.e., the monomers to be used and the ratio of isoolefin to conjugated dienes and cosolvent to be used, is selected. The polymerization reactions are carried out with successively larger amounts of solvent. The first polymerization reaction is set up using 5% by volume of cosolvent, based on the total amount of monomer plus solvent, since smaller amounts are inconvenient. For each subsequent batch, an additional 5% by volume is added. Work is continued until the reaction medium remains clear throughout the reaction. Turbidity is an indication of polymer precipitation, which is causing reactor fouling, or causing gelation.

The polymer formed is based on the Mn value and the mol% content characterized by double bonds. If a higher

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Mn value is desired, one can do so either by reducing it the polymerization temperature or, if possible, by using a temperature lower than that specified above Achieve the amount of solvent, for example 1 to 2% by volume or less, provided that no turbidity occurs. If the polymerization temperature is reduced, it may be necessary to use a larger amount of cosolvent. Consequently, the above-described process of adding additional amounts of solvent to the reaction medium must be continued until the reaction medium again remains clear throughout the polymerization.

If you want to regulate the mol% amount of double bonds somewhat, you can use more or less diene, depending on whether a higher or a lower level of double bonds is desired. When considering the composition of the feed changes, it may be necessary to readjust the required amount of cosolvent accordingly. In general, when the multiolefin content is increased in the monomer feed, the required amount of Cosolvent in the system with acyclic diene such as isoprene decreases and with cyclic diene such as cyclopentadiene the required Amount of cosolvent increases.

The optimal reaction conditions are those under which, for a given double bond content, the maximum

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Mn value is reached at the highest (warmest) temperature. The smaller the amount of cosolvent used, the larger the Mn value becomes. Because of economical reasons the warmest temperature at which the polymerization can be carried out is used. Working at lower Temperatures require larger amounts of cosolvent. The polymerization temperature is preferably above

Another type of preliminary tests to determine the required amount of cosolvent is that reactions in Mass can be carried out without the use of cosolvents. For every monomer feed with a different multiolefin content the polymerization is carried out at gradually lower temperatures until the critical homogeneous polymerization temperature is intended for the composition of the charge. The polymerization is used for different feed compositions repeated, and the values obtained give the critical homogeneous polymerization temperatures as a function the multiolefin content in the feed. Recording this data gives the curve for the critical homogeneous Polymerization temperature analogous to the representation in FIG. 1. The polymer formed is analyzed for its multiolefin content, and the relationship between the mole percentage of double bonds in the polymer and the VoI.% multi

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olefin determined in the feed. The polymers formed in the bulk copolymerization of isobutylene and isoprene or isobutylene-isoprene-cyclopentadiene are unsuitable for commercial use because they have a very low Mn value. To increase the Mn value of the polymers it is necessary to conduct the polymerization at lower temperatures, that is carried out at less than -100 ⁰ C, and to the precipitation of polymer during the polymerization, the addition of co-solvent necessary to prevent.

The amount of solvent used should be kept as low as possible because of excess cosolvent the Mn value is lowered. The composition is used to determine the amount of solvent to be used the monomer feed determined. A suitable polymerization temperature below -100 ° C is selected.

One can determine the minimum required amount of cosolvent for a particular isoolefin-multiolefin by that the polymerization at the critical homogeneous polymerization temperature for the isoolefin-multiolefin feed composition carried out, the polymerization terminated by destruction of the catalyst and the temperature with constant stirring of the system to the desired polymerization temperature

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lowers. The polymer, of course, by definition, below the critical homogeneous polymerization temperature is insoluble, then precipitates and the system takes on a cloudy appearance at. However, the polymer will not gel because the polymerization had stopped before the precipitation. The selected Equal amounts of cosolvent are then added until the cloudiness disappears. The admitted The amount of solvent is a good approximation of the minimum amount of solvent, one for the polymerization of a given isoolefin-multiolefin feed at a given Temperature required.

The term "solvent polymerization" is used in the specification and the claims used to denote a polymerization reaction carried out on the polymer product remains in solution throughout the reaction.

When isoprene is present as the diene to be polymerized, the preferred cosolvents are hexane (s), heptane (s), cyclohexane and methylcyclohexane or mixtures thereof, and these are used in amounts of 5 to 30% by volume, preferably 10 to 25% by volume, for example 10% by volume are used. When cyclopentadiene is present as the diene, the preferred cosolvents are methylcyclohexane (MCH) and cyclohexane or one of these substances containing paraffin mixtures, and these are expediently in Quantities of about 10 to 30% by volume, for example 20 to about 25% by volume, are used.

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The products of the invention have a number of significant advantages over the commercially available butyl rubber products. They have improved cold flow properties and better strength in the uncrosslinked state, with low air permeability and the mechanical damping properties, which have the usual low double bond content Isoolefin copolymers are peculiar to, are also still present. The products according to the invention can also be more versatile vulcanize. While isoolefin-multiolefin copolymers are commonly used for vulcanization, ultra-accelerators, for example Thiuram (Tuads) or dithiocarbamates (Tellurac) have to be used, products according to the invention with thiazole hardeners, for example mercaptobenzothiazole, which is currently used in the vulcanization of rubber products used for general purposes, for example, natural rubber, SBR, polybutadiene and the like can be vulcanized. From certain Reasons, primarily to prevent premature vulcanization (burning), tend to be modern working methods to use a special class of thiazoles, so-called accelerators with delayed action. This delayed Effective accelerators enable the rubber compounds (which already contain the vulcanizing agents) to be processed at the vulcanization temperature for a certain period of time before the start of vulcanization. Such hardening techniques cannot be used for conventional isoolefin copolymers. However, the delayed-action accelerators are for that Vulcanization of isoolefin copolymers according to the invention can advantageously be used.

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Suitable for the vulcanization of products according to the invention Delayed-action accelerators are, for example, the benzathiol sulfenamides of the following general formula

. ■ ΛΛ

, C-S-X

wherein X is an amino group. The amino group is mono- or di-organosubstituted and can be cyclic and

be heterocyclic. For example, X can be - N \ _n or

^R 1

N = R ₀ , where R _{1 is} H or R, R is an organo- or cycloorgano- and R "is a divalent organo radical. Examples of X are cyclohexylamines, tertiary butylamino, diisopropylamino, dicyclohexylamino, pentamethyleneamino, morpholino, 2- (2,6-dimethylmorpholino) etc. Specific examples of such sulfenamides are N, N-diethylbenzenothiazol-2-sulfenamid, N, N-diisopropy1- benzothiazole-2-sulfenamide, N-tertiary-butylbenzothiazole-2-sulfenamide, N-cyclohexylbenzothiazole-2-sulfenamide, N, N-dicyclohexylbenzothiazole-2-sulfenamide, 2- (morpholino) benzothiazolesulfenamide, 2- (2,6-dimethylmorpholino) -benzothiazolesulfenamide, 2-piperidinylbenzothiazolesulfenamide. Generally used as an accelerator with a delayed effect

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for the sulfur vulcanization of polymers according to the invention any benzothiazole sulfenamide can be used.

The delayed-action accelerator is preferably used in the vulcanizable polymer molding composition in amounts of 0.1 to 5% by weight, expediently 0.25 to 3.5% by weight, in particular 0.5 to 3.0% by weight, for example 0.5 to 2.5% by weight, based on the polymer.

It is known that the delayed cure action is sulfur cure and sulfur must be in the polymer blend be incorporated either as elemental sulfur or as non-elemental sulfur. Not more elementary Sulfur is suitably in the form of those compounds which, under vulcanization conditions, are sulfur release to the polymer. Such compounds with non-elemental sulfur are described, for example generally in Vulcanization of Elastomers, Ch. 4, J.C. Ambelang, Reinhold, New York, 1964. Examples of such compounds with non-elemental sulfur are dimorphovinyl disulfide and alkylphenol disulfides. The expression "Sulfur donor" is used in the present specification and claims both for elemental sulfur as well as for the aforementioned compounds with non-elemental sulfur. The one for vulcanization

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required amount of sulfur donor is known. If the sulfur donor is elemental sulfur, it will be in abundance from about 0.1 to 5% by weight, preferably about 0.25 to 3.5% by weight, expediently about 0.5 to about 3.0% by weight, for example 0.5 to about 2.5% by weight, based on the polymer, incorporated into the polymer. If the sulfur donor is a compound with non-elemental sulfur, this will be in a percentage by weight incorporated corresponding to three times the amount required for elemental sulfur. The phrase "connections with non-elemental sulfur "means organic compounds that contain sulfur and have the ability to to release the sulfur under vulcanization conditions, such as diusulphides and polysulphides.

The retarding accelerators can be retarded by means of retarders and activators, which retard the sulfur vulcanization or activate, modified. By adding a retarder, the point in time at which vulcanization begins is postponed even further, while the activator accelerates vulcanization, i.e. a shorter delay time, is achieved.

Suitable retarders for the purposes of the present invention include organic compounds having a pKa value from 2 to less than 7, preferably 3 to 6.5, especially 4 to 6, e.g. 5. The term "pKa value" means the

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Dissociation constant, measured in aprotic solvents, see e.g. Acid-Base Behavior in Aprotic Solvents, NBS Monograph 105, August 1968.

Activators suitable for purposes according to the invention are metal oxides, Hydroxides and alkoxides of metals of groups Ia and Ha of the periodic table and organic compounds with a pKa of 8 to 14, preferably 9 to 12 and especially 9 to 11, e.g. 10.

Examples of retarders are N-nitrosodiphenylamine, N-cyclohexylthiophthalimide, Phthalic anhydride, salicylic acid, benzoic acid and the like. Generally the preferred Retarders nitroso compounds, phthalimides, anhydrides and acids.

Examples of activators are MgO, diphenylguanidine, hexan-1-amine, 1,6-hexanediamine, sodium methoxide and the like. The preferred activators are guanidines and amines.

The retarders and activators are in the polymer in amounts of advantageously 0.1 to 5 wt.%, In particular 0.25 to 3.5% by weight, expediently 0.5 to 3% by weight, e.g. about 2.5% by weight, are incorporated.

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As is known to the person skilled in the art for the processing of elastomers, the copolymers according to the invention can also and terpolymers with suitable fillers and oils and stretched for physical properties of the commercial article manufactured from it can be modified.

The copolymers and terpolymers of the invention can processed without difficulty mixed with other rubbers and, as is known to the person skilled in the art, in their chemical and physical properties are modified. As such other rubber additives one chooses non-polar, crystallizable rubbers (whose crystallization either by low temperature or tension or by both Measures can be triggered), polar, crystallizable rubber types, non-polar, non-crystallizable rubber types and polar, non-crystallizable rubbers. Such rubber products are in the blend composition advantageously in a concentration of 5 to 95 parts by weight, in particular 10 to 50 and especially 10 to 30 parts by weight each 100 parts of the total amount of rubber plus copolymer and / or terpolymer present. Typical examples of these additives are non-polar, crystallizable rubbers such as natural rubber and butyl rubber with a low isoprene content, the has less than 1 mole percent isoprene; polar, crystallizable rubbers such as polychloroprene rubbers (the neoprene types);

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non-polar, non-crystallizable rubbers such as styrene-butadiene copolymers, Polybutadienes and butyl rubber with more than 1 mole percent isoprene; polar, non-crystallizable rubbers such as styrene-acrylonitrile copolymers.

As fillers in molding compositions according to the invention, for example Carbon black, silicon oxide, talc, ground calcium carbonate, water-precipitated calcium carbonate or delaminated, calcined or hydrated clays and mixtures thereof can be used. These fillers are used in quantities of 5 up to 350 parts by weight, preferably 25 to 350 parts by weight and especially 50 to 300 parts by weight per 100 parts of the polymer incorporated into the blend composition. Typically, such fillers have particle sizes of 0.03 to 20 microns, preferably 0.3 to 10 microns, and especially 0.5 to 10 microns. The oil absorption, measured in grams of oil absorbed by 100 g of the filler, is up to 100, preferably 10 to 85 and especially 10 to 75.

The oils used in molding compositions according to the invention for kneading and softening are non-polar process oils less than 2% by weight polar compound as determined by clay gel molecular analysis. These oils are selected from paraffinic ASTM Type 104B oils, defined in ASTM-D-2226-70,

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ASTM Type 102 aromatic oils or ASTM Type 104A naphthenic oils. The oils are said to have a flash point (according to Cleveland
open cup) of at least 177 C, a pour point of at least 4.4 ° C, a viscosity of 70 to 3000 SSU at 37.8 ° C and a number average molecular weight of 300 to 1000,
preferably 300 to 750. Preferred process oils are
paraffinic oils.

The oils are used in a concentration of 5 to 200 parts by weight, preferably 25 to 150 parts by weight and most preferably 50 to 150 parts by weight per 100 parts by weight of polymer incorporated into the mixture composition.

Other plasticizers suitable for the purposes of the invention are ester plasticizers of medium viscosity, which are especially highly effective for increasing the elongation properties, especially at low temperatures. Some examples
for these plasticizers are dioctyl phthalate, dioctyl azelate,
Die octyl sebacate or dibutyl phthalate. The ester plasticizers
are incorporated into the mixture composition in concentrations of 5 to 100 parts by weight, in particular 5 to 75 and preferably 5 to 50 parts by weight per 100 parts by weight of polymer.

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Terpolymers with isoolefins and cyclodienes, e.g. isobutylene-isoprene and cyclopentadiene have greatly improved resistance to ozone degradation compared to acyclic diene copolymers. Although such terpolymers have been postulated to have such improved properties would have to, since the double bonds on it are located in the side chains and not in the main chain, it has not yet been done has been possible to produce practically gel-free isoolefin-cyclodiene terpolymers with a high number average molecular weight, even not with a low proportion of double bonds.

According to the invention it has now become possible to produce such cyclodiene terpolymers both with a low double bond content, as low as 0.5 mol%, and with a high proportion of double bonds as high as 45 mole percent. The polymers preferably contain 5 to 45%, in particular 5 to 40 mol% of double bonds. Even more preferred are those which contain 8 to 40 mol%, especially 8 to 30 mol%, e.g. have 12 to 30 mol% of double bonds.

Due to the relatively low reactivity of the double bonds compared to isoprene copolymers, copolymers are the About 2 to 4 mol.% Cyclopentadiene contain, about as reactive as butyl rubber with an isoprene content of 0.5 to 1.5 mol%, and ultra-

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acceleration required. On the other hand, in the case of copolymers with a high content of double bonds, e.g. with at least 5 mol.%, preferably at least 8 mole percent double bonds sulfur vulcanization using a sustained release accelerator en as previously described, can be carried out.

In general, copolymers according to the invention should not contain more than 45 mol% of double bonds. With a content of Double bonds above 45 mol.% Are made with acyclic multiolefins Polymers produced are difficult to handle and unstable, for example they gel if left to stand. When the multiolefin is a cyclic multiolefin and the proportion of double bonds is more than 45 mol%, the glass transition temperature of the polymer is too high. As a result, the polymers have poor low temperature properties. Preferably contain the copolymers according to the invention 5 to 45 mol% of double bonds, in particular 5 to 40 mol%, even more advantageously 8 up to 40 mol.% and in particular 8 to 30 mol.%, e.g. 12 to 30 mol.% double bonds.

The permeability of isobutylene-isoprene copolymers increases exponentially with the isoprene content and decreases exponentially with cyclopentadiene content in the isobutylene-cyclopentadiene copolymers. In the case of terpolymers made of isobutylene-isoprene

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Cyclopentadiene almost additive. The effect of adding one unit of isoprene to the isobutylene chain can be the effect counteract the addition of one unit of cyclopentadiene with regard to the resulting impermeability value. If e.g. for the permeability of polyisobutylene (or isoprene with few double bonds, e.g. the butyl rubber types)

O O _ -1

a value of about 1 χ 10 (cm sec.) under given test conditions is found, this remains unchanged with isoprene / cyclopentadiene contents of 5/5, 10/10, 20/20 etc. If the ratio is changed, e.g. to 10/20, then the permeability would correspond to the behavior of the predominant Structure (this is cyclopentadiene) will be more similar. The reverse would apply for a ratio of e.g. 20/10.

According to the invention it is thus possible to use isoolefin copolymers and to produce terpolymers that were previously unachievable and that surprisingly all have beneficial properties conventional butyl rubbers with a low double bond content have retained improved vulcanization properties and, in some cases, for example, when it comes to cyclodiene-containing copolymers and terpolymers, improved ozone resistance and Have airtightness.

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The term "essentially gel-free" is used herein Description and the claims copolymers, which are less than 2 wt.%, Preferably less than 1 wt.%, For Example contain 1/2 wt.% Gel. The term "D #", where # is an integer, gives the value for% by volume of cyclopentadiene in a monomer mixture in which D is cyclopentadiene and the integer is the value for% by volume of diene.

In the accompanying drawing illustrate:

Fig. 1 the relation between critical homogeneous polymerization temperature and diene content,

Fig. 2 shows the effect of the polymerization temperature on the number average the molecular weight,

3 shows the effect of the concentration of cosolvent the molecular weight,

4 shows the effect of the polymerization temperature on the reaction,

5 shows the catalyst efficiency as a function of the concentration of cosolvent,

Figure 6 shows the relationship between mole percent cyclopentadiene in the feed compared to mole percent cyclopentadiene in the polymer,

809842/0920

7 shows the relationship between glass transition temperature and

Mol% of cyclopentadiene incorporated in the copolymer,

8 shows a correlation of D # (vol.% CPD in the monomer) to mol.% Cyclopentadiene in the monomer feed.

In the graph according to FIG. 1, the diene content in mol.% In the copolymer formed is on the abscissa, and on the The ordinate shows the temperature in C. The values apply to the maximum monomer concentration. In the areas above the Curves of the respective systems, the copolymers are soluble; gel in the areas below the curves for the systems the copolymers.

In the representation of FIG. 2, the abscissa is the temperature in C and at the same time in one for polymerization temperatures The usual temperature specification is given as 1 / K χ 10, while the average molecular weight is on the ordinate is shown in the form of the number average molecular weight. The relationships illustrated in FIG. 2 were determined on the isobutylene-cyclopentadiene system.

The decrease in molecular weight with increasing concentration of the cosolvent methylcyclohexane in the isobutylene / Cyclopentadiene, as shown in FIG. 3, was determined at -120 ° C. On the abscissa is the concentration of

809842/0920

Cosolvent in% by volume and the average on the ordinate Molecular weight shown as number average. In the diagram of FIG. 4, temperature data are given on the abscissa in the form according to FIG. 2 and on the ordinate the percentage conversion of the isobutylene / cyclopentadiene system investigated worn away. The amount of catalyst and the polymerization time were constant. On the abscissa of the diagram of Fig. 5 is how in Fig. 3, the concentration of the co-solvent methylcyclohexane in the isobutylene / cyclopentadiene system in the feed 95/5 isobutylene / cyclopentadiene and the catalyst efficiency is plotted on the ordinate. The values shown were determined at a polymerization temperature of -120 ° C. In the diagram of FIG. 7, the abscissa indicates the content of cyclopentadiene in the isobutylene / cyclopentadiene systems investigated. The upper scale applies to the cyclopentadiene content in the feed; the lower scale applies to the cyclopentadiene content in the copolymer. Are on the abscissa the glass transition tempera doors (T ") in the form 1 / T", χ 10 K applied. The individual measuring points were at 0% by volume, 3% by volume, 5% by volume and 7% by volume of cyclopentadiene in the monomer charge having polymer samples determined. The illustration in FIG. 8 is used for conversion purposes. as The abscissa is the level of cyclopentadiene in the isobutylene-cyclopentadiene monomer charge and the ordinate shows percentages for cyclopentadiene in the monomer

809842/0920

Send, which for the upper straight line in the diagram as% by weight and for the lower straight line in the diagram are to be understood as mol%. The two straight lines in this diagram can be seen in Connection with the abscissa as a scale for any conversion of cyclopentadiene contents in the system mentioned Serve in% by weight or% by mol or% by volume.

The advantages of the physical properties of molding compositions according to the invention are clear from the following examples and tables recognizable.

example 1

The amounts of used to make these copolymers and terpolymers Reaction components used were measured as volume at -78 C, and the volumes were, if necessary, converted to moles using saved density values.

Varying amounts of isobutylene and isoprene and in some trials Cyclopentadiene-containing monomer mixtures were also used polymerized in the presence of suitable amounts of methylcyclohexane cosolvent. The polymerization was carried out using a 0.061m solution of ethylaluminum dichloride, which with such Speed was added that the temperature in the reaction vessel fluctuated only by 2 of the specified polymerization temperature, initiated. In some cases were

809842/0920

small amounts of a 0.031 M solution of HCl were used, the HCl serving as a cocatalyst for the polymerization. All polymerizations were carried out in a dry, inert atmosphere. The reactions were carried out for a period of 40 minutes, after which time they were stopped by adding a small amount of 10% propanol in pentane. The reaction solutions were then briefly _{treated with gaseous NH 3} and then coagulated by pouring into a hot methanol containing antioxidant. Polymer samples were at about 6O ⁰ C in vacuo. The polymerization details are given in Table 1.

809842/0920

at
game Isobutylene
ml (mole) Table 1 Cyclopenta cosolvent
dien, ml medium, ml Cat.
solution
ml Co-Cat.
solution
ml T, C yield
G 4129
note
a book
Digits 1 2880 (36.4) 800 100 - -110 243 22-110 2 688 (8.70) 200 20th 0.8 -110 49 117-4 3
4th 2720 (34.4)
654 (8.27) 600
100 200
35 2 -119
-110 61
49 50-120
115-3 5 621 (7.85) Details of the polymerization of isobutylene-isoprene
Copolymers and terpolymers with cyclopentadiene 50 50 2 -118 38 114-4 / 8608 Isoprene
ml (mole) NJ 320 (3.72) O 6th 2784 (35.2) 112 (1, 30) 96 (1.30) 800 200 - -1 10 57 23-110 CO 7th 2560 (32.4) 680 (7.90)
196, (2.28) 160 (2.17) 800 200 8th -110 117 97 ts>
O 279 (3.24) 320 (3.72) 480 (5.58)

Cosolvent - methylcyclohexane catalyst solution - 0.061 M EtAlCl ₂ in methylcyclohexane cocatalyst solution - 0.031 HCl in methylcyclohexane

IV QO

cn K) OD CD

Example 2

The polymers of Example 1 were formulated as follows:

Polymer 100 parts by weight

Zinc stearate 1.65

HAF carbon black 60

Hydrocarbon oil plasticizer 20

Antioxidant 1.11

Zinc oxide 5

Sulfur 2.5

Sulfenamide Accelerator 0.75

¹ Flexon 845, ASTM Type 4

Thermoflex A, 50% N-phenyl-ß-naphthylamino, 25% ρ, ρ ¹ -dimethoxydiphenylamine, 25% diphenyl-p-phenylenediamine

Santocure NS; N-tertiary-butylbenzothiazole-2-sulfenamide.

Samples were vulcanized at 169 C so that approximately the same Crosslink densities were achieved. The physical properties of the vulcanized samples of Table 1 are in Table 2 given.

809842/0920

Table 2

Some properties of isobutylene-isoprene copolymers and terpolymers with cyclopentadiene and their vulcanizates (a)

(see also table 1)

At-
game Double bin
dung (b) Mn
x 10 " ³ (c) 1.99
1.77 Moduli, kg / cm Tensile strength
ability ₂
kg / cm strain 4129
note
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Digits 1
2 6.34
10.6 105
91 1, 72 (§ ■ 100% @ 300% 103
127.3 565
355 65-5
119-4 8608 3 16.8 114 1.90 22.5
25.7 54.1
109 139.6 365 67-6 4th 18.6 88 1, 94 16.5 1 10 111.1 255 118-3 ο 5 26.8 103 1.98 32.7 - 137.8 280 1 16-4 u>
ο 6th 7/17 (e) 91 1, 82 33.6 - 166.3 395 65-8 7th 5 / 2O (e) 91 27.4 122.3 151, 8 415 155-1 23.9 107.2

(a) Cured at 169 C to an almost constant crosslink density

(b) Mol.% determined by means of infrared technology

(c) membrane osmometry

(d) Crosslink density, moles / cm 10

(e) isoprene / cyclopentadiene

CT! K)

Polymers and molding compositions according to the invention can be used either in individual batches or in continuous polymerization Manufacture isothermally or at different temperatures. Continuous polymerization is preferred because this procedure is used is more advantageous for industrial working conditions and results in more uniform (more homogeneous) products. The molecular weight distributions (Mw / Mn) are advantageously between 2.0 and 20.

me: kö

8098A2 / 0920

Claims (19)

UEXKÜLL & STOLaERu PATENTANWÄLTE BESELERSTRASSE 4 2000 HAMBURG 52 DR. J.-D. FRHR. by UEXKÜLL DR. ULRICH GRAP STOLBERG DIPL.-ING. JÜRGEN SUCHANTKE Exxon Research and (Prio: April 18, 1977 Engineering Company US 788 504 - 14812) P.O. Box 55 Linden, N.J./V.St.A. Hamburg, April 6, 1978 Gel-free polymer and vulcanizable molding compound containing it Patent claims 1. Essentially gel-free polymer, characterized in that it contains a major proportion of isoolefin having 4 to 10 carbon atoms and contains 5 and 45 mol% of at least one conjugated diolefin having 5 to 9 carbon atoms and has a number average molecular weight of 90,000 to 120,000. 2. Polymer according to claim 1, characterized in that it as isoolefin isobutylene, 2-methyl-l-butene, 3-methyl-1- ORIGINAL INSPECTED butene, 4-methyl-1-pentene, ß-pinene or mixtures thereof contains. 3. Polymer according to claim 1, characterized in that it is isobutylene as the isoolefin and isoprene, piperylene, Contains methylcyclopentadiene or cyclopentadiene. 4. Polymer according to claim 1, characterized in that it is a mixture of isobutylene as the isoolefin and a mixture of diene Cyclopentadiene as the first diene with isoprene, piperylene or methylcyclopentadiene as a second diene. 5. Polymer according to claim 4, characterized in that it contains at least 5 mol% of cyclopentadiene. 6. Polymer according to claim 1 to 4, characterized in that it contains 8 to 40 mol% of diene. 7. Vulcanizable molding compound, characterized in that it (a) a major proportion of substantially gel-free, number average molecular weight from 90,000 to 120,000 polymer of essentially one Isoolefin with 4 to 10 carbon atoms and 5 to 45 mol% of at least one conjugated diene, 8098 4 2/0920 (b) a vulcanizing amount of a sulfur donor, and (c) a delayed-action accelerator contains. 8. Molding composition according to claim 7, characterized in that it is isobutylene as the isoolefin and isoprene, piperylene, Contains methylcyclopentadiene or cyclopentadiene. 9. Molding composition according to claim 7, characterized in that it is isobutylene as the isoolefin and a mixture as the diene of cyclopentadiene as the first diene and isoprene, piperylene or methylcyclopentadiene as the second diene. 10. Molding composition according to claim 9, characterized in that the polymer contained therein is at least 5 mol% of cyclopentadiene contains. 11. Molding composition according to claim 9, characterized in that the diene content is about 8 to 40 mol%. 12. Molding composition according to claim 9, characterized in that the content of the first diene is about 8 to 30 mol%. 809842/0920 13. Molding composition according to claim I _1, characterized in that it contains, as an accelerator with a delayed action, a benzothiazole sulfenamide in an amount of 0.5 to 3% by weight, based on the polymer. 14. Molding composition according to claim 7, characterized in that it contains a retarder with a pKa value of less than 7 incorporated. 15. Molding composition according to claim 7, characterized in that one of the following activators (1) Oxides, hydroxides and alkoxides of metals of the groups IA and HA of the periodic system, (2) organic compounds with a pKa value of 8 to 14 contains. 16. Molding composition according to claim 7, characterized in that it additionally contains a filler in an amount of 5 to 350 parts by weight per 100 parts of the polymer. 17. Molding compound according to one of claims 7 and 16, characterized characterized in that they additionally contain a non-polar process oil in an amount of 5 to 200 parts by weight, based on 100 parts of the polymer. 009842/0920 18. Molding composition according to any one of claims 7, 16 and 17, characterized in that it additionally contains an ester plasticizer in a concentration of 5 to 100 parts by weight per 100 parts of the polymer. 19. Molding composition according to any one of claims 7, 16, 17 and 18, characterized in that it also contains a non-polar crystallizable rubber, a polar one crystallized rubber, a non-polar non-crystallizable rubber and / or a polar one non-crystallizable rubber in a concentration of 5 to 95 parts by weight per 100 parts by weight of the total of rubber and polymer. 809942/0920