SULFONATED COPOLYMER OF AN ISOOLEFIN AND AN ALKYL-STYRENE

Abstract: A sulfonated copolymer of an isoolefin and an alkylstyrene is provided. Organic solutions of these sulfonated copolymers and organic solutions of an interpolymer complex of these sulfonated copolymers and an amine-containing copolymer are also provided.

Description: SULFONATED COPOLYMER OF AN ISOOLEFIN AND AN ALKYL-STYRENE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to novel compositions of a sulfonated copolymer of an isoolefin and an alkyl-styrene and the use of these sulfonated copolymers or complexes of these copolymers with an amine-containing copolymer to thicken the organic liquid Description of Information Disclosures There are many diverse uses for very viscous or gelled solutions of polymers. Physical and chemical processes for preparing such systems are also known. The present invention is directed to a process for gelling a liquid system by mixing into the liquid system the sulfonated polymer or the interpolymer complex of the sulfonated polymer. The potential uses for this process and the resulting products will be apparent from the ensuing description. Some of these uses include their use as a thickening agent for oils, lubricants, in coatings and in oil well drilling uses. The term "gelling" or "gelation" is used herein to denote thickening the liquid sufficiently to produce a semisolid (e.g. grease, petrolatum, gelatin). European Patent Application 8930595.9 filed May 26, 1989 (Publication No. 0344021 published November 29, 1989) discloses copolymers of a isomonoolefin and a para-alkylstyrene and the corresponding halogenated copolymers. U.S. Patent Nos. 4,361,658, 4,322,329 and 4,282,130 are directed to the gelling of the organic liquid by a water insoluble, neutralized sulfonated polymer. The sulfonated copolymer and complexes of the present invention show a great improvement in heat stability and low permeability compared to these known processes. This is useful in coatings and controlled release uses. The process of the present invention permits: (1) the preparation of a polymer solution of a sulfonated copolymer of an isoolefin and an alkyl¬ styrene or a complex of said sulfonated copolymer with an amine-containing copolymer in organic liquid having reasonably low viscosities; and (2) the preparation of extremely viscous solutions or gels of the solutions by applying shear to the solution. SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a sulfonated copolymer of an isomonoolefin having from 4 to 7 carbon atoms and a para-alkylstyrene. In accordance with a second embodiment of the invention, there is provided a solution of an organic liquid and a neutralized sulfonated copolymer of an isomonoolefin having from 4 to 7 carbon atoms and a para-alkylstyrene. In accordance with a third embodiment of the invention, there is provided a solution of an organic liquid and an interpoly er complex comprising a sulfonated copolymer of an isoolefin and an alkylstyrene and an amine-containing copolymer. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel sulfonated copolymers and to a process ' for the thickening or viscosification of an organic solution which includes the steps of forming a solvent system of an organic liquid or oil and, optionally, a polar cosolvent, the polar cosolvent being less than about 15 weight percent of the solvent system, with a viscosity of the solvent system being less than about 100 cps; subsequently forming a solution of a sulfonated copolymer of an isoolefin and an alkyl-styrene or an interpolymer complex of the sulfonated copolymer and a copolymer of styrene/vinylpyridine in the solvent system to form a solution with a concentration of the sulfonated copolymer or the interpolymer complex in the solution ranging from about 0.001 to about 25 weight percent. The component materials of the present process generally include a water insoluble sulfonated copolymer of an isoolefin and an alkyl-styrene interpolymer complex of said sulfonated copolymer and an amine-containing copolymer at a concentration level suitably ranging from about 0.001 to about 25 weight percent, a nonpolar organic liquid and, optionally, a polar cosolvent. Gelation of the organic liquid does not occur if one employs a conventional unsulfonated polymer, or a water soluble, neutralized sulfonated polymer, or a styrene-4-vinylpyridine copolymer in place of the water insoluble sulfonated copolymer, the interpolymer complex thereof having both ionic groups and basic moieties. In general, the interpolymer complex is formed from the interaction of a water insoluble sulfonated copolymer of an isoolefin and an alkyl¬ styrene and a copolymer of styrene/vinylpyridine. The water insoluble sulfonated copolymer generally comprises from about 0.01 to about 500 millimole equivalents (meq.) of pendant sulfonate groups per 100 grams of sulfonated copolymer, preferably from 1 to 100 meq. pendant sulfonate groups. In most instances the sulfonated copolymers utilized in the instant invention are neutralized with the basic materials selected from Groups IA, IIA, IB and IIB of the Periodic Table of Elements and lead, tin and antimony, as well as ammonium and amine counterions. The Periodic Table of Elements referred to herein is in accordance with the table published by Sargent-Welch copyright 1968, Sargent-Welch Scientific Company. Neutralization of the acid form of the sulfonated copolymer is done by the addition of a solution of a basic material such as a basic salt to the acid form of the sulfonated copolymer dissolved in the mixture of the aliphatic alcohol and non-reactive solvent. The basic salt is dissolved in a binary solvent system consisting of water and/or aliphatic alcohol. The cation of the basic salt is selected from antimony, iron, aluminum, lead, or Groups IA, IIA, IIIA, IVA, VA, IB or IIB of the Periodic Table of Elements and mixtures thereof. The transition elements having atomic numbers ranging from 21 to 30 are preferred. The more preferred cation is selected from the group consisting of zinc, copper, iron, nickel, mercury, cadmium, cobalt, and mixtures thereof. The anion of the preferred basic salt is selected from a carboxylic acid having from about 1 to about 4 carbon atoms, a hydroxide or alkoxide and mixtures thereof. The preferred neutralizing agent is a metal acetate, more preferably transition metal salts, such as zinc acetate. Sufficient metal salt of the carboxylic acid is added to the solution of the acid form of the sulfonated copolymer to effect neutralization. It is preferable to neutralize at least 95 percent of the acid groups, more preferably about 98 percent, most preferably 100 percent.. Metal oxides can also be effective in some instances as neutralizing agents. The sulfonated copolymers and base-containing polymers of the present invention may be prepared prior to incorporation into the organic solvent, or by neutralization of the acid form in situ. For example, in the case of the sulfonate-containing species, preferably the acid derivative is neutralized immediately after preparation. For example, if the sulfonation of the copolymer of isobutylene and paramethylstyrene is conducted in solution then the neutralization of that acid derivative can be conducted immediately following the sulfonation procedure. The neutralized polymer may then be isolated by means well known to those skilled in the art, i.e., coagulation, steam stripping or solvent evaporation, because the neutralized polymer has sufficient thermal stability to be dried for employment at a later time in the process of the instant invention. The unneutralized sulfonic acid derivatives may not possess good thermal stability and the above operations avoid that problem. It is also possible to neutralize the acid form of these polymers in situ, however, this is not a preferred operation since in situ neutralization requires preparation of the sulfonic acid in the organic liquid which is to be subjected to the present process, or the acid form of the ionic polymer must be dissolved in said organic liquid. The latter approach may involve handling of an acid form of an ionic polymer which may have limited thermal stability. Therefore, it is quite apparent that the preparation and isolation of a neutralized ionic polymer affords the maximum latitude in formulation, less the problems in handling polymers of limited thermal stability and maximum control over the final mixture of ionic polymer, polar cosolvent and organic liquid. It has been found, surprisingly, that a very important factor in determining the strength of the interaction between the amine-containing and the sulfonate-containing copolymer is the nature of the counterion. There are, broadly speaking, three major classes of such counterions. The first class, which are less preferred, are those metals of Group IA and IIA, which include Li, Na, K, etc.. Be, Mg, Ca, etc. These species do not interact as strongly with amine groups as the more preferred species described below. The preferred metals are commonly defined as members of the transition elements having atomic numbers ranging from 21 to 30. These metal cations are best exemplified by zinc and interact strongly with pyridine and similar amines. Consequently, a zinc neutralized sulfonated copolymer interacts much more strongly with a styrene/vinylpyridine copolymer than does a magnesium- or sodium-neutralized system. It is for this reason that the transition elements are preferred, with zinc, copper, iron, nickel, mercury, cadmium and cobalt being especially preferred. Suitable cations also include titanium, vanadium, chromium, and manganese. A third species which is preferred is the free acid of the sulfonated copolymers, which will also interact with amine-containing polymers. In this latter case, it is clear that the interaction is a classic acid-base interaction, while with the transition metals, a true coordination complex is created, which is due to the donation of the electron pair of the nitrogen element. This distinction is a very important one and sets these complexes apart from classic acid- base interactions. The surprising observation is that such coordination complexes can form in such extreme dilution insofar as interacting groups are concerned, and that they are apparently formed so far removed from their expected stoichiometry (based on small molecule analogs) . Neutralization of the given polymers with appropriate metal hydroxides, metal acetates, metal oxides or ammonium hydroxide, etc. can be conducted by means well known in the art. For example, the sulfonation process, as with butyl rubber containing from 0.3 to 1.0 mole percent unsaturation, can be conducted in a suitable solvent, such as hexane, with acetyl sulfate as the sulfonated agent, such as is described in U.S. Patent No. 3,836,511, the teachings of which are hereby incorporated by reference. The resulting sulfonic acid derivative can then be neutralized with a number of different neutralization agents, such as sodium hydroxide or sodium phenolate and similar metal salts. The amounts of such neutralization agents employed will normally be equal stoichiometrically or in excess to the amount of free acid in the polymer plus any unreacted reagent which is still present. It is preferred that the amount of neutralizing agent be equal to the molar amount of sulfonating agent originally employed, plus 10 percent more to ensure full neutralization. The use of more of such neutralization agent is not critical. Sufficient neutralization agent is necessary to effect at least 50 percent neutralization of the sulfonic acid groups present in the copolymer, preferably at least 90 percent, and more preferably essentially complete neutralization of such acid groups should be effected. The degree of neutralization of the sulfonate groups may vary from 0 (free acid form) to 100 mole percent, preferably 50 to 100 mole percent. With the utilization of neutralized ionomers in the present invention, it is preferred that the degree of neutralization be substantially complete, that is, with no substantial free acid present and without substantial excess of the base other than that needed to insure neutralization. The neutralized ionomers possess greater thermal stability than their acid form. Thus, the polymers which are preferably utilized in the present invention comprise substantially neutralized pendant groups. An excess of the neutralizing material may be utilized without deleterious effect. The sulfonated copolymers of the present invention may have a number average molecular weight ranging from about 1,000 to about 10,000,000, preferably from about 5,000 to about 1,000,000, more preferably from about 10,000 to about 500,000. The sulfonation of the copolymers may be performed by introducing a sulfur trioxide complex into the solution of the copolymer such as the method described in U.S. Patent 3,642,728, the teachings of which are hereby incorporated by reference, wherein a butyl rubber or ethylene-propylene diene elastomers are sulfonated utilizing a sulfur trioxide complex. Suitable sulfonation agents also include the sulfonation agents described in U.S. Patent 3,870,841, the teachings of which are hereby incorporated by reference, such as acetyl sulfonate, i.e., the mixed anhydride of acetic acid and sulfuric acid (CH3COOSO 3 H) , and sulfur trioxide complexes with dioxane, tetrahydrofuran, and trialkyl phosphate complexes, preferably those having a trialkyl phosphate to SO3 ratio of about 1.0. Sulfonation agents such as sulfuric acid and chlorosulfonic acid can also be used. As described in U.S. Patent 3,870,841, the sulfonation agent is introduced into a solution of the polymer which is to be sulfonated in a suitable solvent. For the sulfonation process of the present invention, it is preferred to use mixtures of polar and non-polar organic solvents. A preferred mixture comprises 1,2- dichloroethane and n-hexane. Preferably, the mixture comprises 20 to 90 weight percent of 1,2- dichloroethane. The sulfonated copolymer of an isoolefin and an alkyl-styrene may be represented by the formula: wherein x ranges from about 50 to about 99.5 wt.%, y ranges from about 0.001 to about 2.0 wt. %, Z ranges from about 0.5 to about 50 wt. % and ] _ and R2 are independently selected from an alkyl group having 1 to 4 carbon atoms and x is selected from the group consisting of hydrogen, a metal cation and mixtures thereof. A single sulfonate group is likely to reside in either of the two meta positions, with a lower likelihood of sulfonations at the ortho position or a still lower likelihood of multiple sulfonations on one aromatic ring. The novel sulfonated ionomers and sulfonic acid polymers of the present invention have definite advantages over other known sulfonated ionomers. These advantages are mainly a combination of heat stability, low permeability (relative to permeability of elastomeric ionomers) , and the latitude of further functionalization of the para-alkyl group. These make the novel compositions unique over other elastomeric ionomers. For example, sulfonated-EPDM ionomers display low stability in the sulfonic acid form and a relative high permeability to small molecules; sulfonated butyl ionomers contain unsaturated sites along the backbone that reduce their thermal and ozone stability. The sulfonated copolymer of isoolefin having from 4 to 7 carbon atoms and a para-alkylstyrene have a number average molecular weight (M n ) of at least about 1,000, and preferably at least about 5,000 to about 10,000,000 The sulfonated copolymers also preferably have a ratio of weight average molecular weight (M w ) to number average molecular weight, or M w /M n of less than about 20, more preferably less than about 10, most preferably less than about 5. These sulfonated copolymers of the isoolefinic and para-alkylstyrene have between about 80 to 99.5 weight percent of the isoolefin such as isobutylene and about 0.5 and 20 weight percent of the para-alkylstyrene such as para-methylstyrene. In accordance with another embodiment, however, where glassy or plastic materials are being produced, copolymers may have between about 10 and 99.5 weight percent of the isoolefin, or isobutylene, and about 0.5 and 90 weight percent of the para-alkylstyrene, such as para-methylstyrene. Suitable copolymers of a C 4 to Cη isomonoolefin and a para-alkylstyrene for use as a reactant to produce the polymers of the present invention composition comprise at least 0.5 weight percent of the para-alkylstyrene moiety. The para- alkylstyrene moiety may range from about 0.5 weight percent to about 50 weight percent, preferably from about 1 to about 50 weight percent, more preferably from about 2 to about 20 weight percent of the copolymer. For elastomeric copolymer products, the para-alkylstyrene moiety ranges from about 0.5 to about 20 weight percent. The copolymers of the isomonoolefin and para- alkylstyrene copolymers suitable as reactant of the present invention include copolymers of isomonoolefin having from 4 to 7 carbon atoms and a para- alkylstyrene, such as those described in European patent application 89305395.9 filed May 26, 1989, (Publication No. 0344021 published November 29, 1989). The copolymers have a substantially homogeneous compositional distribution and include the para- alkylstyrene moiety represented by the formula: in which R and R 1 are independently selected from the group consisting of hydrogen, alkyl preferably having from 1 to 5 carbon atoms, primary haloalkyl, secondary haloalkyl preferably having from 1 to 5 carbon atoms, and mixtures thereof. The preferred isomonoolefin comprises isobutylene. The preferred para-alkylstyrene comprises para-methylstyrene. Suitable copolymers of an isomonoolefin and a para-alkylstyrene include copolymers having a number average molecular weight (M n ) of at least about 25,000, preferably at least about 30,000, more preferably at least about 100,000. The copolymers also, preferably, have a ratio of weight average molecular weight (M w ) to number average molecular weight (M n ) , i.e., M w /M n of less than about 6, preferably less than about 4, more preferably less than about 2.5, most preferably less than about 2. The brominated copolymer of the isoolefin and para- alkylstyrene obtained by the polymerization of these particular monomers under certain specific polymerization conditions now permit one to produce copolymers which comprise the direct reaction product (that is, in their as-polymerized form) , and which have unexpectedly homogeneous uniform compositional distributions. Thus, by utilizing the polymerization and bromination procedures set forth herein, the copolymers suitable for the practice of the present invention can be produced. These copolymers, as determined by gel permeation chromatography (GPC) demonstrate narrow molecular weight distributions and substantially homogeneous compositional distributions, or compositional uniformity over the entire range of compositions thereof. At least about 95 weight percent of the copolymer product has a para-alkylstyrene content within about 10 wt. percent, and preferably within about 7 wt. percent, of the average para- alkylstyrene content for the overall composition, and preferably at least about 97 wt. percent of the copolymer product has a para-alkylstyrene content within about 10 wt. percent and preferably within about 7 wt. percent, of the average para-alkylstyrene content for the overall composition. This substantially homogeneous compositional uniformity thus particularly relates to the intercompositional distribution. That is, with the specified copolymers, as between any selected molecular weight fraction the percentage of para-alkylstyrene therein, or the ratio of para- alkylstyrene to isoolefin, will be substantially the same, in the manner set forth above. In addition, since the relative reactivity of para-alkylstyrene with isoolefin such as isobutylene is close to one, the intercompositional distribution of these copolymers will also be substantially homogeneous. That is, these copolymers are essentially random copolymers, and in any particular polymer chain the para-alkylstyrene and isoolefin units will be essentially randomly distributed throughout that chain. The sulfonate level in sulfonated isomers can be described in mole percent sulfonate or sulfur content, but has been previously described in terms of millimole equivalents (meq.) of sulfonate groups per 100 grams of presulfonated backbone polymer. The preferred sulfonation level of the novel polymers ranges from about 0.01 to about 500 meq./100 g in order to render these compositions soluble in organic solvents. Very high sulfonate levels can render sulfonate ionomers water soluble, similar to sulfonated polystyrene ionomers with 500 to 1,000 meq./lOO g. The preferred level of sulfonate moieties in the polymers of the present invention can be achieved by sulfonating copolymer of an isoolefin and an alkylstyrene having lower or higher alkyl-styrene levels. This will change the ratio of sulfonated alkyl-styrene to unsulfonated alkyl-styrene groups and, thereby, the elastomeric nature of the resulting polymers. Compositions that further enhance the viscosities of organic solutions, over those of sulfonated copolymers of an isoolefin and an alkyl¬ styrene salts are solutions of interpolymer complexes obtained by blending sulfonated copolymers of an isoolefin and an alkyl-styrene with anionic polymers. Such complexes can be based on the sulfonic acid form of sulfonated copolymers of an isoolefin and an alkyl¬ styrene or on salts with cations which are transition elements, such as copper, cobalt and nickel or zinc salts of sulfonated copolymers of an isoolefin and an alkyl-styrene. The sulfonic acid, or these salts of sulfonated copolymers of an isoolefin and an alkyl¬ styrene interact strongly with anionic polymers such as styrene vinylpyridine (SVP) , and particularly SVP wherein the vinylpyridine is 4-vinylpyridine. The pyridine or anion content of such anionic polymers can vary from at least two anionic groups per polymeric chain to a very high content of anionic moieties per chain as long as the chain is soluble in the organic solvent of interest. If interpolymer complexes, such as those of the present invention are formed by melt mixing in the bulk, the resulting blend will have a higher melt viscosity and a finer morphology in the case of microphase separated blends. Such microphase separations occur when backbones of blended polymers are incompatible, as is the case for copolymer of an isoolefin and an alkyl-styrene and SVP polymers. Therefore, blends of sulfonated copolymers of an isoolefin and an alkyl-styrene and SVP polymers, wherein the sulfonated copolymer of an isoolefin and an alkylstyrene is either a sulfonic acid or a salt of the preferred cations listed above, form a more compatible blend with smaller microphase separated distances. The preferred ratio of sulfonated copolymers of an isoolefin and an alkyl-styrene or their preferred salts to the anionic polymer is in the vicinity of the stoichiometric ratio between anions to cations of both polymers or more specifically from one tenth to ten times this ratio. The ratio between the two polymers will, therefore, be a function of the anionic and cationic contents in each polymer. The water insoluble base (amino)-containing copolymer may comprise from about 0.1 to 50 weight percent basic groups situated along the chain backbone. The basic groups may be conveniently selected from the groups containing polymerizable primary, secondary and tertiary amine groups. Included in these categories are the pyridine, anilines, pyrroles, amides and other basic polymerizable ammonia derivatives. The base (amine-containing copolymer of the present invention) is selected from the groups consisting of styrene/vinylpyridine copolymer, vinyl-pyridine/ styrene/butadiene terpolymers, isoprene/vinyl-pyridine copolymer, ethylacrylate/vinylpyridine copolymer and alkyl acrylate copolymers with vinylpyridine, where the alkyl group varies in carbon number from 1 to 18, methyl methacrylate/-vinylpyridine copolymer and alkyl methacrylate copolymers with vinylpyridine, wherein the number of carbon groups in the alkyl group varies from 1 to 18 carbon atoms, butadiene/vinylpyridine copolymer, propylene/vinylpyridine block copolymer, ethylene/vinylpyridine block copolymer, t-butyl styrene/vinylpyridine copolymers, and vinylpyridine copolymers with alpha-beta ethylenically unsaturated copolymers or terpolymers. Specific polymers include styrene-4 vinylpyridine, t-butyl styrene-4-vinyl- pyridine, ethylene-4-vinylpyridine copolymers, propylene-4-vinylpyridine copolymers, acrylonitrile-4- vinylpyridine, methyl methacrylate-4-vinylpyridine copolymers, block copolymers of ethylene oxide/4- vinylpyridine, acrylic acid-4-vinylpyridine copolymers, ethylene-propylene4-vinylpyridine terpolymers, isoprene -4-vinylpyridine, 4-vinylpyridine-elastomers, copoly¬ mers and the like. The preferred base containing polymers of the present invention are styrene and 4- vinylpyridine and ethylene-propylene terpolymers with grafted 4-vinylpyridine. The former polymers are the preferred species. The amount of vinyl pyridine in the amine- containing polymer may vary widely. Suitable amounts may include less than 50 weight percent down to at least 0.5 weight percent of the amine-containing polymer. Preferably, the amine content in the basic polymer is expressed in terms of basic nitrogen. In this respect, the nitrogen content in amides and similar nonbasic nitrogen functionality is not part of the interacting species. A minimum of three basic groups must be present on the average per polymer molecule and the basic nitrogen content generally will range from 4 meq. per 100 grams of polymer up to 500 meq. per 100 grams. A range of 8 to 200 meq. per 100 grams is preferred. These materials are prepared through conventional solution, suspension and emulsion copolymerization technique. The copolymers of styrene/vinylpyridine are typically formed by the emulsion copolymerization of freshly distilled styrene and N-vinylpyridine monomers. This method of copolymerization is generally known to those well versed in the art. As noted previously, solution or suspension techniques may also be used to prepare these base-containing polymeric materials. The interpolymer complex of the neutralized sulfonated copolymer and the copolymer of styrene/vinylpyridine is formed by forming a first solution of the neutralized sulfonated copolymer in the previously described solvent system. A second solution of the copolymer of styrene/vinyl pyridine is formed by dissolving the copolymer of styrene/vinylpyridine in an aromatic solvent, such as xylene or benzene. The concentration of the neutralized sulfonated copolymer in the first solution may range from about 0.001 to about 20 grams per deciliter (g/dl) , preferably from about 0.01 to about 15 g/dl. The concentration of the the copolymer of styrene/vinylpyridine in the second solution may range from about 0.01 to about 50 g/dl, preferably from about 0.05 to about 30 g/dl and more preferably from about 0.1 to about 20 g/dl. The first solution of the neutralized sulfonated copolymer and the second solution of the copolymer of styrene/vinylpyridine are mixed together, thereby permitting the interaction of the neutralized sulfonated copolymer and the copolymer of styrene/vinylpyridine to form the water insoluble interpolymer complex. The molar ratio of neutralized sulfonated copolymer to the copolymer of styrene/vinylpyridine in the interpolymer complex ranges from about 0.1 to about 20, preferably from about 0.5 to about 10, and more preferably about 1 to about 5. The organic liquids which may be utilized in the present invention are selected with relation to the sulfonated copolymer and vice versa. The organic liquid is selected from the group consisting essentially of aromatic hydrocarbons, cyclic aliphatic ethers, aliphatic ethers, organic aliphatic esters of organic acids and mixtures thereof. The preferred organic liquid is selected from the group consisting of benzene, toluene, ethyl benzene, xylene, styrene, and mixtures thereof. All viscosity measurements made or referred to in this invention were measured at a shear rate of about 1.0 to 300 l/second at about room temperature. The water insoluble neutralized sulfonated copolymers of the present invention may have from about 0.01 to about 500 meq. pendant neutralized sulfonate groups per 100 grams of the neutralized sulfonated copolymer, preferably from about 1 to about 100, and more preferably from about 1 to about 50, wherein water insoluble refers to the neutralized sulfonated polymer and not to the unneutralized sulfonated polymer or to the unsulfonated polymer. The concentration of the sulfonated copolymer alone or the interpolymer complex of the sulfonated copolymer and an amine-containing copolymer in the final solution may suitably range from about 0.001 to about 25 grams per deciliter (g/dl), preferably about 0.01 to about 15 g/dl, and more preferably about 0.01 to about 10 g/dl. The organic liquids employed in the present invention may have a solubility parameter of less than 10.5. The water employed in the present invention may be tap water or distilled water, wherein the water may contain up to 1.0 weight percent of acids, bases or salts. The method of the present invention includes optionally incorporating a polar cosolvent, in the mixture of organic liquid and water insoluble interpolymer complex to solubilize the pendant sulfonate groups. The polar cosolvent may have a solubility parameter of at least 10.0, preferably at least 11.0, and is water miscible and may comprise from 0.1 to 15.0 weight percent, preferably 0.1 to 5.0 weight percent, of the total mixture of organic liquid, water insoluble sulfonated copolymer and polar cosolvent. The solvent system of polar cosolvent and organic liquid in which the water insoluble interpolymer complex is dissolved suitably contains less than about 15 weight percent of the polar cosolvent, preferably from about 0.1 to about 5.0 weight percent, and more preferably from about .1 to about 5.0 weight percent. The viscosity of the solvent system is generally less than about 1,000 cps, preferably less than about 800 cps, and more preferably less than about 500 cps. Normally, the polar cosolvent will be a liquid at room temperature, however, this is not a requirement. It is preferred, but not required, that the polar cosolvent be soluble or miscible with the organic liquid at the levels employed in this inven¬ tion. The polar cosolvent is selected from the group consisting of water soluble alcohols, amines, di- or trifunctional alcohols, amides, acetamides, phosphates or lactones and mixtures thereof. Especially preferred polar cosolvents are aliphatic alcohols, such as methanol, ethanol, n-propanol, isopropanol, 1,2-propane diol, onethyl ether of ethylene glycol and n- ethyIformamide. The following examples will demonstrate the performance of a sulfonated copolymer of isobutylene and paramethylstyrene and an interpolymer complex consisting of a sulfonated copolymer of isobutylene and para-methyl styrene and a styrene-4-vinylpyridine in specific organic solution environments. Example 1 Preparation of sulfonated isobutylene-p-methylstryene fS-IP and zinc salt of sulfonated isobutylene-p- methylstyrene (Zn-S-IP ) A. lOOg, of IP (isobutylene-p-methylstyrene copolymer) containing 10 wt% para-methylstyrene moieties (PMS) was dissolved in 750 ml of 1,2- dichloroethane and 250 ml of n-hexane at 50 β C. Acetic anhydride, 5.4g, was added and then concentrated sulfuric acid, 3.4 g, was added dropwise. The mixture was stirred at 50°C for one hour to sulfonate the polymer. A solution of zinc acetate dihydrate, 8.6 g. in 80 ml of methanol and 4 ml of water was added to terminate the reaction and form the zinc salt. Polymer product was isolated by steam stripping and drying on a hot mill. The products from these experiments were analyzed for sulfur and zinc content. These results were: B. Similar to above, except reagents (acetic anhydride, sulfur acid, zinc acetate dihydrate) were doubled in quantity. The product (15030-14-1) contained 1.1% sulfur and 2.2% zinc. Example 2 Tensile Properties of Zn-S-IP The polymers of Example 1 were tested for their tensile properties using the following procedures. Some of polymer 15030-13-1 and some of polymer 15030-14-1 were blended with zinc stearate (ZnSt) on a mini ill. 10 parts of Zinc Stearate was used per 100 parts of Zn-S-IP. Some of the original ZN-S-IP polymers, the Zinc Stearate blends of these polymers and the IP backbone used in Example 1 were molded into thin films. The molding was done in a compression press at 150°C where the polymers were pressed down to 0. 03 + 0. 005 inches. If the molded films were not well fused, a few layers were layered up and pressed again until a uniform film was obtained. The molded films were allowed to cool under pressure in a water cooled press. The polymeric films were cut into ASTM micro-dumbbells (0.1 inch wide) and pulled at a rate of 5 inches/minute at ambient temperature, using a tensile testing machine. The tensile properties which were obtained are described in Table I. The data in Table I demonstrates the ionomeric nature of Zn-S-IP polymers. These polymers show increased modulus and highly increased tensile strength over those of the non sulfonated backbone polymer. Also, blending with zinc stearate, which was demonstrated in the literature as an ionic plasticizer for sulfonated ionomers, improved the molding ease and the surface appearance of the molded films and raised the 100 % modulus and the elongation. This shows that the Zn-S-IP polymers of Example 1 behave as ionomers. Polymer 14-1 also exhibited a higher modulus than 13-1. This was consistent with the higher sulfonation level of polymer 14-1. Example 3 Solution Viscosities of Zn-S-IP The Zn-S-IP polymers and the unsulfonated backbone polymer of Example l were dissolved in xylene and in xylene methanol mixtures. 0.4 g of polymer was added to 19.6 g of solvent in a closed glass bottle that was placed on a mixing wheel for gentle mixing. The solvent was composed of mixtures of xylene and methanol. The various solution combinations are shown in Table II. TABLE II UP-J. Polvmer X_£i£Il£ Methanol Viscosity Shear Rate Cominents* (0.4 g) (g) (g) (cP) (1/sec) A Unsulfonated 19.6 — 3.6 — Newtonian Backbone B 13-1 C 13-1 D 14-1 E 14-1 F 13-1 G 13-1 H 13-1 I 13-1 J 13-1 *Newtonian behavior was observed at a shear rate range of 0-300 1/sec. Viscosities were measured with a Haake CV-100 viscometer. Low viscosity solutions (less than 50 cP) were measured with a ME-30 sensor system where shear rate was scanned from 0 to 300 1/sec in 2 minutes. The more viscous solutions were measured with a ZA-15 sensor system. Solutions B and D were scanned from a shear rate of zero to 2.4 1/sec in 0.8 minutes. Solution J was scanned up to a shear rate of 300 1/sec in 2 minutes. This example shows that a low concentration solution of Zn-S-IP in an organic solvent can attain very high viscosities and that viscosity can be greatly suppressed by addition of small amounts of a polar cosolvent such as methanol. Intermediate amounts of methanol lead to intermediate viscosities, or selective evaporation of the polar cosolvent, such as is possible in a methanol-xylene solvent system, could lead to gelation. Example 4 Solution Viscosities of Zn-S-IP Complexes In this example interpolymer complexes were formed in xylene solutions of Zn-S-IP and SVP. A SVP copolymer (707-A) containing about 8 mole % of 4-vinylpyridine, was dissolved in xylene at concentrations of 0.1 g SVP in 19.9 g xylene (solution K) and 0.2 g SVP in 19.8 g xylene (solution L) . Polymers 13-1 and the unsulfonated backbone of examples 1 and 2 were also dissolved in identical concentrations as the above (solutions M, N, 0 , P respectively) . The solutions were prepared using the method of Example 3 and the viscosities of these solutions were measured as in Example 3. Table III shows the resulting viscosities. Table III Ho. Polymer and Weight (g ) K SVP 707A, 0.1 g SVP 707B, 0.2 g M 13-1, 0.1 g N 13-1, 0.2 g O Unsul onated 19.9 1.3 300 Newtonian Backbone, 0.1 g Unsulfonated 19.8 1.4 300 Newtonian Backbone, 0.2 g Solution M of Zn-S-IP, which was a 0.5 solution, is considered a "dilute" solution, since its viscosity approaches the viscosity of the unsulfonated backbone at 0.5% concentration (solution 0). There appears to be no ionic interaction between the Zn-S-IP polymer molecules at 0.5% concentration while at higher concentrations (solution N) there is an interaction with significant viscosification. Interpolymer complexes in solution were formed by adding the solutions of Zn-S-IP to the solutions of SVP, at various volumetric ratios. Methanol was also added to some of the blended solutions in order to dissociate the formed complexes. Viscosities and other observations are shown in Table IV. * Some of the solutions are from Example 3 ** Volume parts of the solutions indicated in the column on left, respectively. The blends of Table IV were first made without adding extra methanol, the total amount of methanol shown in Table IV included some extra methanol added to the blend. Without adding extra methanol, Blend No. 2 was an extremely viscous solution. Blend No. 3 produced a gel like precipitate, Blend No. 4 produced a precipitate of fine flakes and Blend No. 5 produced a shear thickening viscous fluid. Shear thickening could be easily observed by shaking the solution container. When the extra methanol was added to Blends No. 3 and No. 4, the precipitate disappeared and the low viscosity solutions shown in Table IV were formed. Also, blending solutions 0,P,K and L at any combination or ratio, formed low viscosity solutions which were bounded by the viscosities of the solutions used before blending. Example 4 shows that Zn-S-IP can interact with anionic polymers, such as SVP, and form strong interpolymer complexes. Such complexes will precipitate in otherwise good solvents such as xylene. However, an addition of a polar cosolvent, such as methanol, can reduce the strength of interaction to form homogeneous solutions of the interpolymer complex with a viscosity that ranges from high to as low as the blends of the corresponding non-sulfonated analogs.

Claims: CLAIMS : 1. A sulfonated copolymer of an isomonoolefin having from 4 to 7 carbon atoms and a para-alkylstyrene. 2. The sulfonated copolymer of claim 1, wherein said para-alkylstyrene is a para-methylstyrene. 3. The sulfonated copolymer of claim 1, wherein said sulfonated copolymer is represented by the formula: wherein x ranges from about 50 to about 99.5 weight percent, y ranges from about 0.001 to about 2 weight percent, Z ranges from about 0.5 to about 50 weight percent, Ri and R2 are independently selected from an alkyl group having from 1 to 4 carbon atoms, and x is selected from the group consisting of hydrogen, a metal cation, and mixtures thereof. 4. The sulfonated copolymer of claim 3, wherein said metal cation is selected from the group consisting of Groups IA, IIA, IIIA, IVA, VA, IB, IIB of the Periodic table of elements, antimony, iron and mixtures thereof. 5. A solution comprising: (a) an organic liquid selected from the group consisting of an aliphatic hydrocarbon, aromatic hydrocarbon and mixtures thereof; and (b) from about 0.001 to about 20 grams per deciliter of a sulfonated copolymer represented by the formula: -(CH2 - χ~CH2 - ξΑy wherein x ranges from about 50 to about 99.5 weight percent, y ranges from about 0.001 to about 2 weight percent, Z ranges from about 0.5 to about 50 weight percent, Ri and R 2 are independently selected from an alkyl group having from 1 to 4 carbon atoms, and x is selected from the group consisting of hydrogen, a metal cation, and mixtures thereof. 6. The solution of claim 5 wherein said metal cation is selected from the group consisting of Groups IA, IIA, IIIA, IVA, VA, IB, IIB of the Periodic table of elements, antimony, iron and mixtures thereof. 7. The solution of claim 5 additionally comprising a polar cosolvent wherein said polar cosolvent is selected from the group consisting of methanol, ethanol, propanol, isopropanol and mixtures thereof. 8. The solution of claim 5, wherein said polar cosolvent has .a solubility parameter of at least about 10. 9. The solution of claim 5, wherein said organic liquid is selected from the group consisting of aromatic hydrocarbons, ketones, chlorinated aliphatic hydrocarbons, aliphatic hydrocarbons, cyclic aliphatic ethers, aliphatic ethers, aliphatic esters and mixtures thereof. 10. The solution of claim 5, wherein said organic liquid is selected from the group consisting of benzene, toluene, ethyl benzene, xylene, and mixtures thereof. 11. An interpolymeric complex comprising: (a) a sulfonated copolymer of an isoolefin having from 4 to 7 carbon atoms and a para-alkyl styrene; and (b) an amine containing copolymer, wherein a molar ratio of said sulfonated copolymer to said amine containing copolymer ranges from about 0.1 to 20. 12. The interpolymeric complex of claim 11, wherein said sulfonated polymer is represented by the formula: Ri -(CH 2 ~ H) z —(CH 2 - C )χ—CH 2 - CHy wherein x ranges from about 50 to about 99.5 weight percent, y ranges from about 0.001 to about 2 weight percent, Z ranges from about 0.5 to about 50 weight percent, R^ and R2 are independently selected from an alkyl group having about 1 to about 4 carbon atoms and x is a metal cation. 13. The interpolymeric complex of claim 12, wherein said amine-containing copolymer is a copolymer of styrene/vinyl pyridine and said interpolymer has a molar ratio of said sulfonated copolymer to said copolymer of styrene/vinyl pyridine ranging from about 0.1 to about 20.0. 14. The interpolymeric complex of claim 13, wherein said metal cation is a transition metal having an atomic number ranging from 21 to 30. 15. The interpolymer complex of claim 12, wherein said metal cation is selected from the group consisting of zinc, copper, iron, nickel, mercury, cadmium, and mixtures thereof. 16. The interpolymer complex of claim 12, wherein said sulfonated copolymer is a neutralized sulfonated copolymer and wherein said neutralized sulfonated copolymers has from about 0.01 to about 500 meq. of pendant neutralized sulfonate groups per 100 grams of the neutralized sulfonated copolymer. 17. The interpolymer complex of claim 13, wherein said vinylpyridine in said complex ranges from less than 50 weight percent to at least about 0.5 weight percent. 18. A solution comprising: (a) an organic liquid selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons and mixtures thereof; and (b) from about 0.001 to about 25 grams per deciliter of an interpolymeric complex comprising a sulfonated copolymer of an isoolefin having from 1 to 4 carbon atoms and a para-alkylstyrene; and an amine containing copolymer, wherein a molar ratio of said sulfonated copolymer to said amine-containing copolymer ranges about 0.1 to 20. 19. The solution of claim 18, wherein said sulfonated polymer is represented by the formula: wherein x ranges from about 50 to about 99.5 weight percent, y ranges from about 0.001 to about 2 weight percent, Z ranges from about 0.5 to about 50 weight percent, R^ and R2 are independently selected from an alkyl group having 1 to 4 carbon atoms, and x is a metal cation. 20. The solution of claim 18, wherein said amine containing copolymer is a copolymer of styrene/vinyl pyridine. 21. The solution of claim 19, wherein said metal cation is selected from the group consisting of Groups IA, IIA, IIIA, IVA, VA, IB, IIB of the Periodic Table of Elements, antimony, iron and mixtures thereof. 22. The solution of claim 19 wherein said sulfonated copolymer is a neutralized sulfonated copolymer and wherein said neutralized sulfonated copolymer has from about 0.01 to about 500 meq. of pendant neutralized sulfonate groups per 100 grams of the neutralized sulfonated copolymer. 23. The solution of claim 19, wherein said metal cation is a transition metal having an atomic number ranging from 21 to 30. 24. The solution according to claim 20 wherein said vinylpyridine in said complex ranges from less than 50 weight percent to at least about 0.5 weight percent. 25. The solution of claim 18 additionally comprising a cosolvent selected from the group consisting of methanol, ethanol, propanol, isopropanol, nd mixtures thereof. 26. The solution of claim 25, wherein said polar cosolvent has a solubility parameter of at least about 10. 27. The solution of claim 18, wherein said organic liquid is selected from the group consisting of aromatic hydrocarbons, ketones, chlorinated aliphatic hydrocarbons, aliphatic hydrocarbons, cyclic aliphatic ethers, aliphatic ethers, aliphatic esters, and mixtures thereof. 28. The solution according to claim 18, wherein said organic liquid is selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, and mixtures thereof. 29. The solution of claim 18, wherein said organic liquid is selected from the group consisting of benzene, toluene, ethyl benzene, xylene, styrene, and mixtures thereof.

Inventors: DUVDEVANI ILAN, FUSCO JAMES VINCENT, NEWMAN NEIL FREDERICK, DUVDEVANI, ILAN, FUSCO, JAMES, VINCENT, NEWMAN, NEIL, FREDERICK
Applicants: EXXON CHEMICAL PATENTS INC, EXXON CHEMICAL PATENTS INC.
Application year: 1992
Main classification: C08F8
IPC codes: C08F8, C08F12, C08F210, C08F212