CH656888A5 - COLD VOLCANIZABLE RUBBER COMPOSITION AND ITEMS THEREOF. - Google Patents

Description

It was an object of the invention to provide a cold-vulcanizable rubber composition which advantageously combines rubber technology and anaerobic technology which is curable under anaerobic conditions, which can preferably be used as or in the form of films, tapes and the like, and which has rubber characteristics and flexible characteristics when cured.

The object is achieved according to the invention in the composition characterized in claim 1.

Advantageous developments of the subject matter of the invention can be found in the dependent claims. 5 An anaerobic system is usually defined as a system which, in its compounded form, remains stable in the presence of oxygen, but which polymerizes to a higher polymeric state in the absence of oxygen. This actually means that the presence of oxygen prevents or delays the polymerization (hardening).

An anaerobic curing is preferably carried out at ambient temperatures or room temperature; however, the rate of polymerization is a function of the monomer, the initiator and depends on whether inhibitors and / or accelerators are present or not. For example, the term "anaerobic curing" has been widely used to refer to a polymerization that takes place even at temperatures higher than ambient temperature, the main factor being that curing is inhibited in the presence of oxygen, but in the absence or in the presence of it reduced oxygen concentration occurs. Elevated temperatures and / or metals also accelerate the polymerization.

For reasons of expediency, the curing process of the compositions according to the invention is referred to as "cold vulcanization" and is described as a curing process by anaerobic agents from liquid long-chain segments or unvulcanized rubber to high molecular weight polymer material with suitable values for the crosslink density to ensure the rubber-like Properties defined. The rubber-like properties (rubber elasticity) are all properties of a high elastic reaction of a tough flexible material with high moduli. A definition of rubber elasticity is found in F.W. Billmeyer's "Textbook of Polymer Science" (John Wiley & Sons, Fourth Printing, 1966), p. 189.

The invention and preferred embodiments are described below.

The invention relates to compositions which achieve rubber-like properties on aerobic curing.

The term "anaerobic monomer" as used herein refers to a monomer having at least one and preferably two polymerizable acrylate ester residues, usually at the ends of a backbone, which polymerize or cure in the presence of an initiator with essentially the exclusion of oxygen or air. The anaerobic monomer is referred to here as an acrylate ester and is to be understood in a broader sense, in which it also includes esters of α-substituted acrylic acid.

One of the most preferred groups of anaerobic monomers that can be used in the composition of the invention are polyacrylate esters, which have the following general formula I;

0 u h, c = c - c - 0

b

- (ch21

c = R2

ch.

t'-rj in which R1 is selected from the group of hydrogen, lower alkyl radicals having 1 to 4 carbon atoms,

Hydroxyalkyl radicals with 1 to 4 carbon atoms and radicals of the general formula II

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- CHg - 0 - C - ç = CH2

(II)

R

wherein R2 is selected from the group of hydrogen, halogen and lower alkyl radicals having 1 to 4 carbon atoms; R3 is selected from the group of hydrogen, hydroxyl and radicals of the general formula III

_ 0 - C - C

R

CÏÏ2

(III)

m is an integer equal to at least 1, e.g. is from 1 to 15 or greater, and preferably from 1 to 8 inclusive; n is an integer equal to at least 1, e.g. Is 1 to 20 or more; and p is one of the following digits: 0, 1.

Polyacrylate esters which are used in the composition according to the 20 invention and correspond to the general formula I above are to be represented, for example, without limitation: di-, tri- and tetramethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, polyethylene glycol dimethacrylate, di- (pentamethylene glycol) dimeth-25 acrylate, Tetraäthylenglykoldiacrylat, Tetraäthylenglykoldi- (chloroacrylate), Diglyzerindiacrylat, Diglyzerintetramethacry-lat, tetramethylene dimethacrylate, ethylene dimethacrylate, neo-pentylglykoldiacrylat, trimethylolpropane triacrylate, the reaction product of hydrogenated bisphenol A with 2,4-tolylene diisocyanate and 2-hydroxyethyl methacrylate so and the reaction product of Methylene diphenyl isocyanate and 2-hydroxymethacrylate or 3-hydroxymethacrylate. The above monomers need not be in the pure state, but may include commercially available varieties containing inhibitors 35 or stabilizers such as quinones.

Monoacrylate esters, especially those esters in which the non-acrylate portion of the ester contains a hydroxyl, mercapto or amino group or other reactive substituent which serves as a site for potential crosslinking with itself and / or the synthetic rubbery polymer.

The choice of the anaerobic monomer that can be used in the composition according to the invention

depends on the specially selected synthetic rubber-like polymer. The anaerobic monomer must be soluble or completely miscible in the synthetic rubber-like polymer.

The solubility or miscibility of the anaerobic monomer in the rubbery polymer can easily be determined as follows: (1) If the polymer is a liquid and the anaerobic monomer is a liquid, the visual assessment shows the solubility or miscibility; (2) If the polymer has solid properties, the compounded material is applied to paper after the monomer has been mixed with the polymer. An oily, wet spot appears on the paper if the monomer is not soluble in the polymer or is not fully miscible with it.

The term “polymers” used here denotes 60 customary known synthetic rubbers from the group of acrylonitrile / butadiene with a weight-average molecular weight of 50,000 to 500,000 and terminal and /

or pendant vinyl groups or acrylonitrile / butadiene with reactive terminal carboy, mercapto or amino 65 groups; Polybutadiene; Polyisoprene; Butadiene / styrenes and acrylonitrile / butadiene / styrenes.

Acrylonitrile / butadiene is available from B.F. Goodrich

Co. under the trade name Hycar and the preferred polymer has a weight average molecular weight in the range of 50,000 to 500,000.

The butadiene-styrene copolymer is called SBR and generally has a butadiene to styrene ratio of about 78:22.

The acrylonitrile / butadiene / styrenes preferably contain 15 to 35% acrylonitrile and 15 to 35% butadiene.

The catalyst or initiator for this system preferably consists of a peroxy compound and a co-initiator.

The preferred peroxy initiators are the hydroperoxy initiator and particularly preferably the organic hydroperoxides which have the formula R4OOH, where R4 is generally a hydrocarbon radical having up to 18 carbon atoms, preferably an alkyl, aryl or aralkyl radical having up to 12 carbon atoms. Typical examples of such hydroperoxides are cumene hydroperoxide, tert-butyl hydroperoxide and methyl ethyl ketone hydroperoxide. However, other peroxy initiators such as hydrogen peroxide, dihydroperoxides, or materials such as certain organic peroxides or peresters that hydrolyze or decompose to form hydroperoxides and dihydroperoxides, and dihydroperoxides can also be used. Examples of such peroxy initiators are benzoyl peroxide and 2,5-dimethylhexyl-2,5-dihydroperoxide. These compounds are known in the literature.

Co-initiators which are suitable for the composition according to the invention are the known hydrazine derivatives which are suitable for initiating the free radical polymerizations, and in particular compounds having the general formula IV

R5 - N

l

H

0

11 6

N - C - R

I.

H

(IV)

wherein R5 can be selected from the following radicals: alkyl, preferably lower alkyl having 1 to 6 carbon atoms, either straight-chain or branched, particularly preferably methyl, ethyl or isopropyl; Cycloalkyl containing up to 8 carbon atoms; Alkenyl containing up to 10, preferably 2 to 5 carbon atoms; Cycloalkenyl containing up to 10, preferably up to 6, carbon atoms; Aryl, including halogen-substituted aryl, hydroxy-substituted aryl, nitro-substituted aryl and aryl substituted by lower alkyl or alkoxy groups having 1 to 6 carbon atoms. R6 can be hydrogen or any of the radicals given for R15 and can additionally be an amino or substituted amino group or a carbonyl group to which a non-reactive group is attached, such as lower alkyl containing 1 to about 4 carbon atoms.

Examples of compounds according to the above formula are to be shown without limitation 1-acetyl-2-phenylhydrazine, 1-acetyl-2- (p-toyl) hydrazine, 1-benzoyl-2-phenylhydrazine, 1 - (1 '1', 1'-trifluoroacetyl) -2,2-phenylhydrazine, 1,5-diphenylcarbohydrazide, l-formyl-2-phenylhydrazine, 1 -acetyl-2- (p-bromophenyl) hydrazine, 1 -acetyl-2- (p -nitrophe-nyl) -hydrazine, 1 -acetyl-2- (p-methoxyphenyl) -hydrazine, l-acetyl-2,2- (2'-phenylethyl) -hydrazine and l-acetyl-2-methylhydrazine.

The effectiveness of the co-initiators appears to require the presence of a proton on each of the nitrogen atoms, but not more than 1 proton on each nitrogen atom.

If this criterion is met, the exact nature of the R groups does not appear to be critical, provided, of course, that the R groups cannot be selected such that they significantly affect the storage properties of the compound

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intervene or affect the performance of the accelerator for its intended purpose. So the choice of specific groups R and combinations thereof is a matter of trial and selection. Of course, it is obvious to the expert that

that an optimal selection of the groups R from the curable ester monomers or mixture of monomers, and from the initiator or optionally used co-initiator.

The catalyst system, which also includes the co-initiators, is 0.1-7% of the weight of the anaerobic monomer. A slight effect is found below the lower limit. The upper limit is not critical, with significant improvements usually not found above about 5 wt% concentrations. For practical reasons, a concentration range of 0.1 to 2.0% by weight leads to an optimal overall benefit and this range is therefore particularly preferred.

Accelerators are also often used in the compositions of the invention. Examples include organic amides such as formamide and succinimide and the like; tertiary amines such as tributylamine and triethylamine and the like; aromatic tertiary amines such as dimethyl-p-toluidine and the like; and organic sulfimides such as benzoic acid sulfimide and the like. Any accelerators present are in the range from about 0.1 to about 7% by weight and preferably between 2 and 3% by weight.

Stabilizers or inhibitors used in the composition of the invention include benzoquinone, naphthaquinone, hydroquinones, monomethyl ether of hydroquinone, hindered phenols and the like. The concentration of the inhibitors is in the range from about 25 to about 1000 ppm.

The compositions of the invention may contain any other ingredients which do not significantly alter the anaerobic properties or affect the workability of the compositions. Examples of such additional components are fillers, such as titanium dioxide, Teflon, glass, nylon fibers and the like, which are expediently added to the rubber-like polymer; Dyes, plasticizers or plasticizers and the like.

Various types of products can be prepared from the compositions, for example in the form of films, tapes, sheets, or layered on a peelable base. The composition can be extruded, rolled or deposited from a solution, slurry or latex, depending on the intended use for the product and the physical properties of the compounded formulation. The solution, slurry or latex can be used "as such" without intermediate deposition on any other basis, such as a paint.

Compositions according to the invention are used as a material for insulating, sealing or carrier materials in the form of tapes or foils. Such tapes can be placed on threaded objects such as pipe fittings and can replace the currently used Teflon tapes because they provide superior sealing results and are resistant to the effects of pressure and solvents. The materials retain their flexible characteristics during hardening and when used on threaded parts such as pipe threads, the hardened product provides both a sealing and a locking function.

For convenience of storage and use, the tapes of compositions according to the invention may be coated with a thin layer of a polymer

Material like nylon can be covered. While the polymeric coating is sufficiently thick to allow the tape to roll and prevent it from sticking to itself, it is still thin enough to allow air access through the coating to the tape.

When coated with a polymeric coating, the coating material should be soluble in alcohol and is usually deposited on the unvulcanized polymeric composition from an alcoholic solution, preferably from methanol. Nylon-6-12 (DuPont Elvamide 8061) and nylon-12-12 (Vestamid XI874, X2191 and X2302) were used for coatings.

Regardless of their natural shape or form, the products described here are stable in storage and suitable for surviving normal storage and transport conditions. They do not polymerize (harden) as long as they are kept in reasonably thin sheets (such as 1.27 cm or less) and in contact with air or another oxygen supplier. If they are placed between non-porous surfaces or otherwise brought into an oxygen-free atmosphere, the compositions will harden. The cured product has the properties of a vulcanized rubber and can consist of the reaction product of the copolymer and monomer, of the complete intermeshing of the polymer in the polymerized monomer, or a combination of both.

The polymerized product, which has the characteristics of a vulcanized rubber, can be distinguished from the unpolymerized reaction products by its extractability. The unpolymerized reaction products are soluble in organic solvents, whereas the polymerized product is insoluble in organic solvents or is therefore not extractable. The polymerized product is at least 75% and preferably 80% non-extractable.

The product obtained after curing maintains its flexibility and forms a seal that resists pressures from 10.3 to 17.2 jxPa and is resistant to solvents. These characteristics are maintained over a wide temperature range from -54 to 204 ° C.

Although curing usually takes place at room temperature, the time required for curing can be reduced by exposing the assembly containing the composition to moderate temperatures, such as 37 to 94 ° C.

The sodium salt of ethylenediaminetetraacetate, if used in the formulation, can be added to either the monomer composition or the polymer-monomer composition.

Examples

The following examples serve to illustrate typical compositions within the scope of the invention and methods for producing and using these compositions. The examples are not meant to be limiting. Unless otherwise stated, all ratios and percentages in the examples are by weight.

example 1

An anaerobic curing polymerizable monomer formulation was prepared by mixing the ingredients listed in Table I in approximately the amounts indicated.

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Table I

Components weight (g)

Polyethylene glycol dimethacrylate

(average molecular weight 330) 100

l-acetyl-2-phenylhydrazine 0.002

Benzoic acid sulfimide 1.6

Cumene hydroperoxide 3.0

1,4-p-naphthoquinone solution

(100 ppm in methanol) 0.2

To a mixture consisting of 50 g of acrylonitrile / butadiene (Hycar 1492) and 20 g of titanium dioxide, mixed in a Waring mixer, 25 g of the mixture in Table I and 1 g of a solution of sodium ethylenediaminetetraacetate (73.5% methanol, 23 % Water and 3.5% sodium ethylenediaminetetraacetate) added.

The resulting mixture was processed in a rubber roll mill until the lumps disappeared and then extruded through a slot die about 508 µm thick. The extruded material was then passed through modified heated chill rolls (only one roll was heated) with an opening of about 0.0762 µm.

The resulting material was in tape form from about 0.00508 to about 0.635 cm thick and was applied to a peelable paper strip and wound on take-up spools.

Example 2

A copolymeric-anaerobic monomer mixture was prepared according to the procedure of Example 1.

The resulting mixture was extruded through a slot die about 508 Jim thick. The extruded material was then passed through modified heated cooling rolls, as in Example 1.

When leaving the cooling roll (calender rolls), the material was passed through a nylon 6-12 solution (6 to 7% nylon 6-12, in methanol) and then through an air column heated to about 52 ° C. The methanol was evaporated in the hot air, covering the rubber tape with a layer of nylon from 12.7 to 25.4 µm thick, and the coated tape was then wound onto a paper spool without a paper layer separating the layers of the tape .

To use the tape, it was applied to the threads and stretched to break the nylon cover.

Example 3

30 g of the mixture in Table 1 and 1.5 g of a solution of sodium ethylenediaminetetraacetate were added to a mixture of 50 g of acrylonitrile / butadiene (Hycar 1492), 19.5 g of titanium dioxide and 0.5 g of Teflon, mixed in a Waring mixer (73.5% methanol, 23% water and 3.5% sodium ethylenediaminetetraacetate) added.

The resulting mixture was processed in a rubber roller mill until the lumps disappeared and then extruded through a slot die about 508 µm thick. The extruded material was then passed through a modified heated chill roll, as in Example 1.

When leaving the calendering rolls, the material was passed through an approximately 6 to 7% nylon 6-12 solution (in methanol) and then through a column with air, heated to approximately 52 ° C. The methanol was evaporated in the hot air process, covering the rubber band with a thin layer of nylon. In the unhardened state, this tape has a storage life of more than one year. If it is in the hardened state, the tape has an elongation of 470%, a tensile strength in the mass of 6.8 jiPa and a working range of - 54 to 204 ° C.

The tape was applied to a pressure-deformable iron T-joint (0.95 cm) and subjected to a torque of 41 Nm and load tests with the following results:

a) after immediate assembly or after 24 hours and 48 hours of curing, the seals did not leak at a hydraulic pressure exceeding 13.6 jiPa;

b) no leakage occurred when the combined T-pieces (hardened for 24 hours) were exposed to temperatures of 93 to 204 ° C for 500 hours and at a pressure of about 10.3 uPa;

c) there was no leakage at pressures of 20.7 jiPa after curing the T arrangement for 24 hours when immersed in the following solvents at the specified temperatures for eight weeks: transmission fluids 149 ° C, motor oil 149 ° C, 50% glycol / water 132 ° C; Gasoline 82 ° C and air 86 ° C;

d) various T-pieces (hardened for 24 hours), which were exposed to 95% moisture at 38 ° C for 1000 hours, showed no leakage after a pressure of 13.8 p.Pa.

Example 4

The mixture and procedure of Example 1 were repeated using t-butyl hydroperoxide instead of cumene hydroperoxide.

Example 5

To a mixture of 75 g of acrylonitrile / butadiene (Hycar 1494) and 20 g of titanium dioxide, mixed in a Waring mixer, 25 g of the mixture from Table I and 1 g of a sodium ethylenediaminetetraacetate solution (73.5% methanol, 23% water and 3 , 5% sodium ethylenediamine traacetate) added.

The resulting mixture was processed in a rubber roll mill and processed by calender rolling to a film material of 50.8 µm in thickness.

Example 6

Useful uncured tape and film materials were obtained using the following copolymers and anaerobic monomers according to the procedure of Examples 1,2 and / or 5.

Copolymer Monomer a) acrylonitrile / butadiene lauryl methacrylate b) butadiene / styrene tetramethylene glycol dimeth-

acrylate c) acrylonitrile / butadiene with terminal

Carboxy groups 3-hydroxypropyl methacrylate d) butadiene / styrene 80% styrene / 20%

Pentaethylene glycol dimethacrylate e) acrylonitrile / butadiene 2-hydroxyethyl methacrylate

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The processing of the final product by extrusion, calendering or solution deposition depends on the feasibility of the operation and the physical properties of the product. Most products are a rubbery or supple solid that is without

7,656,888

Application of excessive forces can be extruded. If the product is not easily extrudable in nature, it can be processed by calendering rolls or by separation from solution.

G

Claims (24)

656 888 1. Cold-vulcanizable rubber composition, characterized by a mixture of a) rubber, selected from the group of acrylonitrile / butadiene copolymers with a weight average molecular weight of 50,000 to 500,000 and terminal and / or pendant vinyl groups, acrylonitrile / butadiene Copolymers with terminal reactive carboxy, mercapto or amino groups, polybutadiene, polyisoprene, acrylonitrile / butadiene / styrene copolymers and butadiene / styrene copolymers, b) anaerobic acrylate ester monomers which is soluble or miscible in the polymer mentioned under a), 30 to 80% of component a) and the remaining 70 to 20% of the total of components a) and b) Component b) is eliminated, c) 0.1 to 7% of the weight of the anaerobic monomer of a catalyst system, and d) a stabilizer, wherein the composition under anaerobic conditions by polymerization, in which high-molecular material with properties of vulcanized rubber is formed, can give a product in which the portion of its mass derived from the monomer or components and component a) is at least 75% non-extractable solid mass. 2. Composition according to claim 1, characterized in that the mixture also contains e) an accelerator. 2nd PATENT CLAIMS 3rd 656 888 3. Composition according to claim 1 or 2, characterized in that the anaerobic acrylic atester monomer mentioned under b) of the general formula I. 0 contains one or more fillers in an amount of 5 to 20 wt .-%, based on the total weight of the composition. 4. Composition according to claim 1 or 2, characterized in that the rubber is acrylonitrile / butadiene copolymer with terminal and / or pendant vinyl groups and with a weight average molecular weight of 50,000 to 500,000. 5. Composition according to one of claims 1 to 3, characterized in that the mixture (ii) means R2 is hydrogen, halogen or a lower alkyl radical with 1 to 4 carbon atoms, R3 is hydrogen, hydroxyl or a radical of the general formula III 50 60 comprises, wherein R5 is alkyl, preferably having 1-6 carbon atoms, straight-chain or branched; Cycloalkyl of up to 8 15 carbon atoms; Alkenyl with up to 10, preferably 2-5 carbon atoms; Cycloalkenyl having up to 10, preferably up to 6 carbon atoms or aryl, and R6 is hydrogen or has one of the meanings given for R5, or an optionally substituted amino group or a carbonyl group to which a non-reactive group such as e.g. Alkyl with 1-4 carbon atoms, and the peroxy initiator from the group of hydrogen peroxide, hydroperoxides of the general formula R4OOH, in which R4 is a hydrocarbon radical with up to 12 carbon atoms selected from alkyl, aryl and aralkyl, peroxides, peresters and dihydroperoxides is selected. 6. Composition according to claim 1, characterized in that the catalyst system mentioned under c) is a peroxy initiator and as a co-initiator a compound of the general formula N - 0 r "h9c = c-c — o-j— (ch2) m c- r2 -C — 0- -c-c = ch- <D corresponds to what R 'is hydrogen, a lower alkyl radical having 1 to 4 carbon atoms, a hydroxyalkyl radical having 1 to 4 carbon atoms or a radical of the general formula II 0 -ch2-o - c c = ch, i ' r2 - 0 - c - c = ch- i * - n2 (iii) means m is an integer greater than or equal to 1, n is an integer greater than or equal to 1 and p is 0 or 1. 7. The composition according to claim 6, characterized in that the peroxy initiator is cumene hydroperoxide and the co-initiator is l-acetyl-2-phenylhydrazine. 3o 8. The composition according to claim 2, characterized in that the accelerator is selected from the group of organic amides, tertiary alkyl amines, aromatic tertiary amines and organic sulfimide. 9. The composition according to claim 8, characterized in that the accelerator is an organic sulfimide. 10. The composition according to claim 9, characterized in that the organic sulfimide is benzoic acid sulfimide. 11. The composition according to claim 10, characterized 40 characterized in that the stabilizer mentioned under d) is selected from the group of benzoquinone, naphthoquinone, hydroquinone, monomethyl ether of hydroquinone and sterically hindered phenols. 12. The composition according to claim 11, characterized 45 characterized that the stabilizer is naphthoquinone. 13. The composition according to claim 12, characterized in that the anaerobic acrylate ester monomer is polyethylene glycol dimethacrylate. 14. The composition according to claim 13, characterized in that the polyethylene glycol dimethacrylate has a molecular weight of about 330. 15. The composition according to claim 14, characterized in that of the total mass of components a) and b) 60 to 75% to component a) and the remaining 40 to 25% to component b). 16. The composition according to claim 5, characterized in that the filler is selected from titanium dioxide in the range from 5 to 20% by weight and polytetrafluoroethylene in the range from 0 to 10% by weight and the total weight of the fillers is not 20% by weight exceeds, the percentages by weight based on the total composition. 17. The composition according to claim 16, characterized in that the filler is a mixture of titanium dioxide in the range from 18 to 19.5% by weight and polytetrafluoroethylene in the range from 0.5 to 2% by weight. 18. The composition according to claim 16, characterized in that the filler is titanium dioxide in the range of 18 to 20 wt .-%. 19. Cold-vulcanizable tape of a composition according to claim 2 with a thickness in the range of 0.00508 to 0.635 cm as an insulating or sealing material. 20. Tape according to claim 19, characterized in that the composition is one according to claim 2 and one of claims 4, 6, 7, 9-12, 14, 15, 17 and 18. 21. Tape according to claim 19, characterized in that the composition is that of claims 2 and 18 and that the tape is coated with a polymeric coating having a thickness of 12.7 to 25.4 µm, which coating allows air to enter the rubber composition. 22. Tape according to claim 21, characterized in that the polymeric coating is nylon-6.12. 23, cold-vulcanizable film of a composition according to claim 2 with a thickness in the range of 0.00508 to 0.0381 cm as a sealing or carrier material. 24. A film according to claim 23, characterized in that that the composition is one according to claim 2 and any of claims 4,6, 7,9-12, 14, 15, 17 and 18. Anaerobically curable adhesive compositions are known and their use has become increasingly important in the industry as an insulating agent, sealant and because of their adhesive properties. Anaerobic insulating agents and adhesives are commonly used in a form from water-like to light-weight fat-like consistency. The composition in this form "wets" the surface to be bound. Disadvantages are associated with conventional anaerobic compositions currently on the market for certain applications. The fields of application of anaerobic compositions can be greatly increased if the composition is in a form with fixed characteristics. In addition, many applications, such as seals, may require the polymerized (hardened) composition to be resistant to solvents and maintain flexibility. Synthetic rubbers have many of these desired properties, but their use is limited due to the relatively drastic means required to cure the rubber, such as high temperatures or radiation.