HK1060584A - Halogen- and sulfur-free shaped articles comprising peroxide curable compounds of butyl rubber - Google Patents

Description

Halogen-free and sulfur-free shaped articles containing peroxide-cured compounds of butyl rubber

Technical Field

The present invention relates to shaped articles useful in high purity applications comprising at least one peroxide cured compound comprising a butyl polymer containing less than 15 wt.% of solid matter that is insoluble in cyclohexane boiling under reflux conditions for 60 minutes. In another aspect, the invention relates to a sealing material and a medical device comprising at least one peroxide cured compound comprising a butyl polymer containing less than 15% by weight of solid matter that is insoluble in cyclohexane boiling under reflux conditions for 60 minutes. In another aspect, the invention relates to a fuel cell comprising at least one peroxide cured compound comprising a butyl polymer containing less than 15 wt% solid matter of cyclohexane that is insoluble in boiling under reflux conditions for 60 minutes. In another aspect, the present invention relates to halogen-free and sulfur-free shaped articles.

Background

Butyl rubber is known to have excellent insulating and gas barrier properties. Generally commercial butyl polymers are prepared by a cationic polymerization process at low temperatures using a Lewis acid catalyst, typically aluminum trichloride. The most commonly used method is to use methyl chloride as a diluent for the reaction mixture, the polymerization is carried out at a temperature below-90 ℃ and finally the polymer is obtained in a slurry of the diluent. In addition, it is also possible to produce the polymer in a diluent which acts as a solvent for the polymer (e.g., hydrocarbons such as pentane, hexane, heptane and the like). Conventional processes may be used in the rubber manufacturing industry to recover polymer products.

In many of its applications, butyl rubber is used in the form of a vulcanized compound. The vulcanization systems typically used for butyl rubber include sulfur, quinoids, resins, sulfur donors, and low sulfur high performance vulcanization accelerators. However, sulphur residues in the compound are generally undesirable, for example they promote corrosion of parts in contact with the compound.

High performance applications such as condenser caps or butyl rubber for medical devices require halogen-free and sulfur-free compounds. In this case, it is preferred that the curing system be peroxide-based, since it produces articles free of harmful residues. In addition, peroxide cured compounds have higher heat resistance and other advantages compared to sulfur cured materials.

It is well known to those skilled in the art that bromobutyl rubbers can be cured with peroxides (e.g., Brydson "Rubber Chemistry" 1978, page 318). However, residual halogen in the cured compound is undesirable in certain high purity applications such as condenser caps. Bromobutyl rubber also contains high concentrations of stabilizers as well as vulcanization inhibitors such as epoxidized soybean oil or calcium stearate. These leachable chemicals limit the use of bromobutyl rubber in medical applications.

If peroxides are used for the crosslinking and vulcanization of conventional butyl rubbers, the main chain of the rubber is degraded and a satisfactorily vulcanized product cannot be obtained.

One way to obtain peroxide cured butyl rubber is to use conventional (regular) butyl rubber having ｃA vinyl aromatic compound such as Divinylbenzene (DVB) and an organic peroxide as disclosed in JP- ｃA-107738/1994. Another similar method for obtaining ｃA partially crosslinked butyl rubber is to use ｃA conventional butyl rubber having ｃA polyfunctional monomer having an electron-withdrawing group (ethylene glycol dimethacrylate, trimethylolpropane triacrylate, N, N' -m-phenylene dimaleimide (dimaleimide), etc.) and an organic peroxide, which is disclosed in JP-A-172547/1994. The disadvantage of these processes is that the resulting compound is contaminated with low molecular weight agents added to initiate crosslinking, which do not react sufficiently with the rubber in the solid state. In addition, the action of peroxides in conventional butyl rubber can lead to the formation of certain low molecular weight compounds in degraded rubber. The final products based on these compounds may have undesirable properties, such as leaching out of the low molecular weight substances and accelerated ageing.

The presently preferred method is to use commercial pre-crosslinked butyl rubber, such as commercially available Bayer^XL-10000 (or XL-20 and XL-50 from the outset), which can be crosslinked with peroxides, see, for example, Walker et al "journal of the Institute of the Rubber Industry" 8(2), "1974, 64-68. XL-10000 is partially crosslinked with divinylbenzene already at the polymerization stage. No peroxide will be present during the polymerization process by cationic mechanism. This gives ｃA "cleaner" article than the partially crosslinked butyl rubber disclosed in JP-A-107738/1994. In the latter case, the vulcanization must be continued for a sufficient time for the two functional groups of the DVB molecule to react and be incorporated into the polymer chain.

Although the commercial pre-crosslinked polymers described have excellent properties in many applications, their gel content is at least 50 wt%, sometimes making it difficult to uniformly disperse the fillers and curatives normally used during vulcanization. This increases the likelihood of under-and over-cured areas in the rubber article, which can exhibit poor physical properties and unpredictable results. In addition, the Mooney viscosity of the rubber is very high, typically 60-70 units (1 '+ 8' @125 ℃ C.) which can present significant processing difficulties, particularly during the compounding and sheeting stages.

Improved processability polymers are often added to pre-crosslinked butyl rubber to overcome some of these problems. These polymers are particularly useful for improving the compounding or kneading properties of rubber compositions. They include natural rubbers, synthetic rubbers (e.g., IR, BR, SBR, CR, NBR, IIR, EPM, EPDM, acrylic rubber, EVA, urethane rubber, silicone rubber, and fluororubber), and thermoplastic elastomers (e.g., styrene, olefin, vinyl chloride, ester, amide, and urethane series). These processability-improving polymers are used in amounts of up to 100 parts by weight, preferably up to 50 parts by weight, most preferably up to 30 parts by weight, per 100 parts by weight of partially crosslinked butyl rubber. But the presence of other rubbers can impair the properties of the butyl rubber.

Co-pending Canadian application CA-2,316,741 discloses polymers of isobutylene, isoprene, Divinylbenzene (DVB) and chain transfer agents such as diisobutylene which are substantially gel-free and have improved processability. The above application is silent with respect to peroxide curing and high purity applications.

Disclosure of Invention

The invention provides a rubber compound, which comprises:

a. at least one elastomeric polymer comprising at least one member derived from C₄-C₇Isomonoolefin monomer, at least one C₄-C₁₄Multiolefin monomer or beta-pinene, at least one polyeneA hydrocarbon crosslinker and at least one chain transfer agent, said polymer containing less than 15% by weight of solid matter of cyclohexane that is insoluble in boiling under reflux conditions in 60 minutes,

b. at least one filler and

c. a peroxide cure system suitable for use in the manufacture of shaped articles for high purity applications.

Another aspect of the present invention is to provide a vulcanized rubber part for high purity applications.

Another aspect of the invention is to provide a condenser cover comprising said substantially gel-free peroxide-cured compound interposed between said dynamic device and static structure at the point of attachment.

Another aspect of the invention is to provide a medical device comprising said peroxide-cured compound substantially free of gel.

Drawings

FIG. 1 shows the MDR plots for stocks 1 and 2.

Detailed Description

The present invention relates to butyl rubber polymers. The terms "butyl rubber", "butyl polymer" and "butyl rubber polymer" are used interchangeably in this specification. Although the prior art using butyl rubber mentions by including C₄-C₇Isomonoolefin monomer and C₄-C₁₄Polymers prepared by reacting a multiolefin monomer or a monomer mixture of beta-pinene, however, the invention is particularly directed to polymers comprising monomers derived from at least one C₄-C₇Isomonoolefin monomer, at least one C₄-C₁₄Multiolefin monomer or beta-pinene, at least one multiolefin cross-linkingAn elastomeric polymer of repeating units of a linking agent and at least one chain transfer agent. The butyl polymer of the present invention is preferably non-halogenated.

In connection with the present invention, the term "substantially gel-free" is understood to mean a polymer containing less than 15% by weight, preferably less than 10% by weight, in particular less than 5% by weight, of solid matter insoluble in cyclohexane boiling under reflux conditions within 60 minutes.

The present invention is not limited to any particular C₄-C₇An isomonoolefin monomer. Preferred is C₄-C₇The monoolefin is isobutylene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 4-methyl-1-pentene and mixtures thereof. Most preferred C₄-C₇The isomonoolefin monomer is isobutylene.

Furthermore, the present invention is not limited to any particular C₄-C₁₄A polyene. However, C, conjugated or not₄-C₁₄Dienes are particularly useful. Preferred is C₄-C₁₄The multiolefin monomer is isoprene, butadiene, 2-methylbutadiene, 2, 4-dimethylbutadiene, piperylene (piperyline), 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, 2-methyl-1, 6-heptadiene, cyclopentadiene, methylcyclopentadiene, cyclohexadiene, 1-vinyl-cyclohexadiene or mixtures thereof. Most preferred C₄-C₁₄The multiolefin monomer is isoprene.

The present invention is also not limited to any particular multiolefin cross-linking agent. Preferably, the multiolefin cross-linking agent is a hydrocarbon compound of a multiolefin bond. Examples thereof are norbornadiene, 2-isopropenylnorbornene, 5-vinyl-2-norbornene, 1, 3, 5-hexatriene, 2-phenyl-1, 3-butadiene, divinylbenzene, diisopropenylbenzene, divinyltoluene, divinylxylene or C of the above-mentioned compound₁-C₂₀Alkyl substituted derivatives. More preferably, the multiolefin cross-linking agent is divinylbenzene, diisopropenylbenzene, divinylToluene, divinylxylene or C of said compounds₁-C₂₀Alkyl substituted derivatives. Most preferably, the multiolefin crosslinking agent is divinylbenzene or diisopropenylbenzene.

As will be clear to those skilled in the art, the chemical formulas of the preferred multiolefin monomers and multiolefin crosslinkers overlap. It will be appreciated by those skilled in the art that the differences between these compounds are functional differences. Monomers tend to grow in one dimension, while crosslinkers tend to react in two or more chains. Whether the compounds are reacted under the given conditions, as crosslinkers or as monomers can be obtained directly without error, easily and unambiguously by means of a few very limited preliminary experiments. While an increase in crosslinker concentration will result in a directly related increase in crosslink density within the polymer, an increase in monomer concentration will not generally affect crosslink density in the same manner. Preferred multiolefin monomers will not cause crosslinking if present in the reaction mixture in an amount of up to 5 mole%.

Further, the present invention is not limited to any particular chain transfer agent. However, the chain transfer agent should preferably be a strong chain transfer agent, i.e. it should be able to react with the growing polymer chain, stop its further growth and subsequently initiate a new polymer chain. The type and amount of chain transfer agent depends on the amount of cross-linking agent. At low crosslinker concentrations, low amounts of chain transfer agent and/or weak chain transfer agents may be employed. However, as the crosslinker concentration increases, the chain transfer agent concentration should increase and/or a stronger chain transfer agent should be selected. The use of weak chain transfer agents should be avoided as too much may reduce the polarity of the solvent mixture and also make the process uneconomical. The strength of the chain transfer agent can be determined conventionally, see for example J.Macromol.Sci. -chem., A1(16) p.995-1004 (1967). The number called the transfer constant represents its strength. The transfer constant of 1-butene is 0 according to the values disclosed in this article. Preferably, the chain transfer agent has a transfer coefficient of at least 10, more preferably at least 50. Non-limiting examples of useful chain transfer agents are piperylene, 1-methylcycloheptene, 1-methyl-1-cyclopentene, 2-ethyl-1-hexene, 2, 4, 4-trimethyl-1-pentene, indene, and mixtures thereof. The most preferred chain transfer agent is 2, 4, 4-trimethyl-1-pentene.

Preferably, the monomer mixture to be polymerized comprises 65 to 98.98% by weight of at least one C₄～C₇Isomonoolefin monomer, 1.0-20 wt% of at least one C₄～C₁₄The multifunctional crosslinking agent comprises a polyene monomer or beta-pinene, 0.01-15 wt% of a multifunctional crosslinking agent and 0.01-10 wt% of a chain transfer agent. More preferably, the monomer mixture comprises 72 to 98.9 wt% of C₄～C₇Isomonoolefin monomer, 1.0-10 wt% of C₄～C₁₄The multifunctional crosslinking agent comprises a polyene monomer or beta-pinene, 0.05-10 wt% of a multifunctional crosslinking agent and 0.05-8 wt% of a chain transfer agent. Most preferably, the monomer mixture comprises 85 to 98.85 wt% C₄～C₇Isomonoolefin monomer, 1.0-5 wt% of C₄～C₁₄The multifunctional crosslinking agent comprises a polyene monomer or beta-pinene, 0.1-5 wt% of a multifunctional crosslinking agent and 0.05-5 wt% of a chain transfer agent. It is obvious to the person skilled in the art that the total amount of all monomers will amount to 100% by weight.

The monomer mixture may contain minor amounts of one or more additional polymerizable comonomers. For example, the monomer mixture may contain minor amounts of styrenic monomers such as p-methylstyrene, styrene, α -methylstyrene, p-chlorostyrene, p-methoxystyrene, indene (including indene derivatives) and mixtures thereof. If present, it is preferred to use up to 5.0% by weight of the monomer mixture of styrenic monomers. C₄～C₇Isomonoolefin monomer and/or C₄～C₁₄The value of the multiolefin monomer or β -pinene must therefore be adjusted to again obtain a total of 100% by weight.

It is even possible to use other monomers in the monomer mixture, provided, of course, that they can copolymerize with the other monomers in the monomer mixture.

The present invention is not limited to a particular process for preparing/polymerizing the monomer mixture. Such polymerizations are well known to those skilled in the art and generally involve contacting the reaction mixture described above with a catalyst system. Preferably, the polymerization is carried out at temperatures conventional in the production of butyl polymers, for example-100 ℃ to +50 ℃. The polymers may be produced by polymerization in solution or by a slurry polymerization process. The polymerization is preferably carried out in suspension (slurry process), see for example Ullmann's Encyclopedia of Industrial Chemistry (Fifth, complete revived Edition, volume A23; editor et al, pages 290-292).

The polymer of the present invention preferably has a Mooney viscosity ML (1+8 at 125 ℃) of 5 to 40 units, more preferably 7 to 35 units.

As an example, in one embodiment, the polymerization is conducted in the presence of an inert aliphatic hydrocarbon diluent (e.g., n-hexane) and a catalyst mixture comprising a major amount (80 to 99 mole%) of a dialkylaluminum halide (e.g., diethylaluminum chloride), a minor amount (1 to 20 mole%) of a monoalkylaluminum dihalide (e.g., isobutylaluminum dichloride), and a minor amount (0.01 to 10ppm) of at least one member selected from the group consisting of water, alumoxane (e.g., methylalumoxane), and mixtures thereof. Of course, other catalyst systems conventionally used to produce butyl polymers may be used to produce the butyl polymers used herein, see for example "cationic polymerization of olefins" by Joseph p. Kennedy: an important finding "(John Wiley & Sons, Inc.  1975, pages 10-12).

The polymerization may be carried out continuously or batchwise. In the case of continuous operation, the process is preferably carried out with the following three feed streams:

I) solvent/diluent + isomonoolefin (preferably isobutylene)

II) multiolefins (preferably dienes, piperylenes), polyfunctional crosslinkers and chain transfer agents

III) catalysts

In the case of batch operation, the process can be carried out, for example, as follows: the reactor, pre-cooled to the reaction temperature, is charged with solvent or diluent and reactants. The initiator is then pumped in the form of a dilute solution, in such a way that the heat of polymerization can be dissipated without problems. The course of the reaction can be monitored by means of the release of heat.

The compound also comprises at least one active or inactive filler. The fillers are preferably:

highly dispersed silicas, for example prepared by precipitation of silicate solutions or flame hydrolysis of silicon halides, with specific surface areas of 5 to 1000m²(ii)/g, the primary particle size is 10 to 400 nm; the silica can optionally also be present in the form of mixed oxides with other metal oxides, such as oxides of Al, Mg, Ca, Ba, Zn, Zr and Ti;

synthetic silicates, such as aluminum silicate and alkaline earth metal silicates, such as magnesium silicate or calcium silicate, having a BET specific surface area of 20 to 400m²(ii)/g, the primary particle diameter is 10 to 400 nm;

natural silicates, such as kaolin and other naturally occurring silicas;

glass fibers and glass fiber products (wovens, extrudates) or glass microbeads;

metal oxides, such as zinc oxide, calcium oxide, magnesium oxide and aluminum oxide;

metal carbonates, such as magnesium carbonate, calcium carbonate and zinc carbonate;

metal hydroxides, such as aluminum hydroxide and magnesium hydroxide;

-carbon black; the carbon black used here is prepared by the lamp black, furnace black or gas black process and preferably has a BET (DIN 66131) specific surface area of 20 to 200m²(iv)/g, for example SAF, ISAF, HAF, FEF or GPF carbon black;

-a rubber sol, in particular based on polybutadiene, butadiene/styrene copolymers, butadiene/acrylonitrile copolymers and polychloroprene;

or mixtures thereof.

Preferred mineral fillers include silica, silicates, clays such as bentonite, gypsum, alumina, titanium dioxide, talc, mixtures thereof and the like. These mineral particles have hydroxyl groups on their surface, making them hydrophilic and oleophobic. This exacerbates the difficulty of obtaining good interaction between the filler particles and the tetrapolymer. For many purposes, the preferred mineral is silica, especially silica produced by the carbon dioxide precipitation process of sodium silicate. Dried amorphous silica particles suitable for use in the present invention may have an average agglomerate particle size of from 1 to 100 microns, preferably from 10 to 50 microns, most preferably from 10 to 25 microns. It is preferred that less than 10 volume percent of the agglomerate particles have a size of less than 5 microns or greater than 50 microns. Suitable amorphous dry silicas generally have a BET surface area, determined in accordance with DIN (Deutsche Industrie norm)66131, of from 50 to 450 square meters per gram, and a DBP absorption, determined in accordance with DIN53601, of from 150 to 400 grams per 100 grams of silica, and a drying loss, determined in accordance with DIN ISO 787/11, of from 0 to 10 percent by weight. Suitable silica fillers may be available under the trade name HiSil^210、HiSl^233 and HiSl^243 were obtained from PPG Industries inc. Also suitable are Vulkasil from Bayer AG^S and Vulkasil^N。

It may be advantageous to use a combination of carbon black and mineral filler in the inventive compound. In such a combination, the ratio of mineral filler to carbon black is generally in the range of 0.05 to 20, preferably 0.1 to 10. It is generally advantageous for the rubber composition of the present invention to contain carbon black in an amount of 20 to 200 parts by weight, preferably 30 to 150 parts by weight, more preferably 40 to 100 parts by weight.

The compound also includes at least one peroxide cure system. The present invention is not limited to a particular peroxide curing system. For example, inorganic or organic peroxides are suitable. Preferred are organic peroxides such as dialkyl peroxides, ketal peroxides, aralkyl peroxides, peroxide ethers, peroxide esters, e.g. di-tert-butyl peroxide, bis- (tert-butylperoxyisopropyl) -benzene, dicumyl peroxide, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) -hexane, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) -hexene- (3), 1-bis- (tert-butylperoxy) -3, 3, 5-trimethylcyclohexane, benzoyl peroxide, tert-butylcumyl peroxide and tert-butylperbenzoate. The amount of peroxide in the compound is generally from 1 to 10phr (per 100 rubber), preferably from 4 to 8 phr. The subsequent vulcanization is generally carried out at a temperature of from 100 to 200 ℃ and preferably from 130 to 180 ℃. Peroxides can be advantageously applied in a polymer bound (bound) form. Suitable systems are commercially available, such as polydispersion t (vc) D-40 (polymer-bound di-tert-butyl peroxy-isopropylbenzene) from Rhein Chemie Rheinau GmbH, D.

The compound may further comprise other natural or synthetic rubbers, such as BR (polybutadiene), ABR (butadiene/acrylic acid-C), if not preferred₁-C₄Alkyl ester-copolymers), CR (polychloroprene), IR (polyisoprene), SBR (styrene/butadiene copolymer) having a styrene content of 1 to 60% by weight, NBR (butadiene/acrylonitrile copolymer having an acrylonitrile content of 5 to 60% by weight), HNBR (partially or fully halogenated NBR rubber), EPDM (ethylene/propylene/diene copolymer), FKM (fluoropolymer or fluororubber) and mixtures of the given polymers.

The rubber composition of the present invention may further contain auxiliary products for rubbers, such as reaction accelerators, vulcanization acceleration auxiliaries, antioxidants, foaming agents, anti-aging agents, heat stabilizers, light stabilizers, ozone stabilizers, processing aids, plasticizers, tackifiers, foaming agents, dyes, pigments, waxes, fillers, organic acids, inhibitors, metal oxides, and activators such as triethanolamine, polyethylene glycol, hexanetriol, etc., which are known to the rubber industry. The rubber auxiliaries are used in conventional amounts, which depend inter alia on the intended use. The conventional amount is 0.1 to 50% by weight based on the rubber. Preferably, the composition further comprises 0.1 to 20phr of an organic fatty acid, preferably an unsaturated fatty acid having one, two or more carbon double bonds in the molecule, more preferably 10% by weight or more of a conjugated diene acid having at least one conjugated carbon-carbon double bond in the molecule. Preferably, these fatty acids have from 8 to 22 carbon atoms, more preferably from 12 to 18 carbon atoms. Examples include stearic acid, palmitic acid and oleic acid and their calcium-, zinc-, magnesium-, potassium-and ammonium salts.

The ingredients of the final compound are suitably mixed together at an elevated temperature of 25 to 200 ℃. Typically the mixing time does not exceed 1 hour and a time of 2 to 30 minutes is usually sufficient. The mixing is suitably carried out in an internal mixer such as a Banbury mixer, a Haake or Brabender miniature internal mixer. The two-roll mill also provides good dispersion of the additives within the elastomer. The extruder also provides good mixing and allows for shorter mixing times. The mixing can be carried out in two or more stages and can be carried out in different equipment, for example one stage in an internal mixer and one stage in an extruder. It should be noted, however, that no undesirable pre-crosslinking (═ scorch) occurs during the compounding stage. For compounding and vulcanization, see also: encyclopedia of Polymer Science and Engineering, Vol.4, part 66 and beyond (compounding) and Vol.17, part 666 and beyond (vulcanization).

Further, the present invention provides shaped vulcanized rubber parts for high purity applications comprising said substantially gel-free peroxide-cured compound. The rubber parts are suitable for many high purity applications, such as containers for pharmaceuticals, in particular stoppers and seals for glass or plastic vials, tubes, syringe parts and bags for medical and non-medical applications, condenser caps and seals for fuel cells, parts for electronic equipment, in particular insulating parts, seals and parts for containers containing electrolytes.

The invention will be further described by the following examples.

Examples

Methyl chloride (Dow Chemical) and isobutylene monomer (Matheson, 99%) used as polymerization diluents were transferred to the reactor by condensing the vapor phase. Aluminum chloride (99.99%), isoprene (99%) and 2, 4, 4-trimethyl-1-pentene (97%) were obtained from Aldrich. The inhibitor was expelled from the isoprene by expelling a disposable column with inhibitor from Aldrich. Commercial divinylbenzene (ca. 64%) was obtained from Dow Chemical.

The mixing of the compounds containing carbon black (IRB #7) and peroxide (DI-CUP40C, Struktol Canada Ltd.) was carried out with a Brabender miniature internal mixer (Brabender MIM) from C.W., which was driven by a drive unit (Plasticorder)^Type PL-V151) and a data interface module.

Mooney viscosity measurements were performed on a Monsanto MV 2000 Mooney Viscometer according to ASTM standard D-1646.

Moving DieRheometer (MDR) measurements were carried out on a Monsanto MDR 2000(E) according to ASTM standard D-5289. The upper die oscillates through a small arc of 1 degree.

The solubility of the polymer was determined after the sample was refluxed in cyclohexane for 60 minutes.

Example 1

Commercial butyl Polymer (Bayer) was compounded using the following formulation^Butyl 402, copolymer of isobutylene and isoprene):

butyl polymer: 100phr

Carbon black (IRB # 7): 50phr

Peroxide (DI-CUP 40C): 1.0phr

The mixing was carried out in a Brabender internal mixer (capacity about 75 ml). The starting temperature was 60 ℃ and the mixing speed was 50 rpm. The following steps are carried out:

and (3) 0 minute: addition of Polymer

1.5 minutes: adding carbon black in incremental manner

7.0 min: adding peroxide

8.0 min: discharging the rubber compound

The resulting compound was passed 6 times through a small nip mill (6 "12").

The compound was subjected to an MDR test to determine cure performance. The MDR diagram is given in fig. 1.

Example 2

To a 50mL Erlenmeyer flask was added 0.45 grams of AlCl₃Then 100mL of methyl chloride was added at-30 ℃. The resulting solution was stirred at-30 ℃ for 30 minutes and then cooled to-95 ℃, thereby forming a catalyst solution.

To a 2000mL glass reactor equipped with an overhead stirrer, 900mL of methyl chloride was added at-95 deg.C, followed by 100.0mL of isobutylene at-95 deg.C, 3.0mL of isoprene at room temperature, 4.0mL of commercial DVB at room temperature, and 3.0mL of 2, 4, 4-trimethyl-1-pentene at room temperature. The reaction mixture was cooled to-95 ℃ and 10.0mL of catalyst solution was added to start the reaction.

Under a dry nitrogen atmosphere, in MBRAUN^The reaction was carried out in a dry box. After 5 minutes, the reaction was stopped by adding 10mL of ethanol containing some sodium hydroxide to the reaction mixture.

The resulting polymer was steam coagulated and dried on a 6 "x 12" mill at about 105 ℃ and then dried to constant weight in a vacuum oven at 50 ℃. The Mooney viscosity of the rubber was 7.5 units (1 '+ 8', at 125 ℃) and the solubility in cyclohexane was 98.0% by weight.

The polymer was compounded using the same formulation and procedure as given in example 1. The compound (compound 2) was subjected to an MDR test to determine the cure performance. Figure 1 gives the MDR diagram.

The above examples demonstrate that: substantially gel-free polymers are peroxide cured, unlike conventional butyl rubber. Meanwhile, as can be seen from the Mooney viscosity and the content of insoluble fraction, the polymer obtained in the presence of the chain transfer agent is significantly different from the commercial pre-crosslinked polymer.

Claims (11)

1. A shaped vulcanized article suitable for high purity applications comprising at least one compound comprising:

a. at least one elastomeric polymer comprising at least one member derived from C₄～C₇Isomonoolefin monomer, at least one C₄～C₁₄A multiolefin monomer or repeating units of beta-pinene, at least one multiolefin cross-linking agent and at least one chain transfer agent, said polymer containing less than 15% by weight of solid matter insoluble in cyclohexane boiling under reflux conditions in 60 minutes,

b. at least one filler and

c. a peroxide curing system.

2. The article of claim 1, wherein C in the compound₄-C₇The isomonoolefin monomer is selected from the group consisting of isobutylene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 4-methyl-1-pentene, and mixtures thereof.

3. Article according to claim 1 or 2, wherein C in the size₄-C₁₄The multiolefin monomer is 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, 2-methyl-1, 6-heptadiene, cyclopentadiene, methylcyclopentadiene, cyclohexadiene, 1-vinyl-cyclohexadiene and mixtures thereof.

4. The article according to any of claims 1 to 3, wherein the multiolefin cross-linking agent in the size is selected from norbornadiene, 2-isopropenylnorbornene, 2-vinylnorbornene, 1, 3, 5-hexatriene, 2-phenyl-1, 3-butadiene, divinylbenzene, diisopropenylbenzene, divinyltoluene, divinylxylene or C of the aforementioned compounds₁-C₂₀Alkyl substituted derivatives.

5. The article of any of claims 1-4 wherein the chain transfer agent is selected from the group consisting of piperylene, 1-methylcycloheptene, 1-methyl-1-cyclopentene, 2-ethyl-1-hexene, 2, 4, 4-trimethyl-1-pentene, indene, and mixtures thereof.

6. The article according to any of claims 1 to 5, wherein the peroxide system in the compound is an organic peroxide.

7. The article according to any one of claims 1 to 6, wherein the article is halogen-free and sulfur-free.

8. An article according to any one of claims 1 to 7 in the form of a condenser cap.

9. An article according to any one of claims 1 to 7 in the form of a medical device.

10. A medical device comprising the article of any one of claims 1-7.

11. A fuel cell comprising the article of any one of claims 1 to 7.