Cross-linking epihalohydrin polymers
[ Apr. 1,1975  
 [ 4 l CROSS-LINKING EPll-[ALOHYDRIN POLYMERS [75] Inventor: Joseph E. Mirolli, Beaumont. Tex.  
 [73] Assignee: Hercules Incorporated, Wilmington,  
 Del.  
 [22] Filed: May 15, 1973 [21] Appl. No.: 360,692  
  52 us. Cl..... 260/78.4 D. 260/l8 EP, 260/37 EP. 260/457 R [51] Int. Cl C08g 23/20 [58] Field of Search 260/784 D, 78.4 EP, 2 EP, 260/2 A. 2 EC, 2 N, 2 BP, 18 EP [56] References Cited UNITED STATES PATENTS 3.239.486 3/1060 Willis 260/45.75 334L491 9/1967 Robinson ct al 260/45.75 3.720841 4/l973 Mirolli ct al. 260/79 Primary hlmmiiu&#39;rHarry Wong, Jr. .is&#39;sl&#39;xlu/zl l:&#39;.\&#39;amimrJohn Kight. lll AIM/714&#39;). Agent. or Firm-Marion C. Staves [57] ABSTRACT Epihalohydrin polymers and copolymers can be crosslinked with a polycarboxyplate polyanion having the formula where R is a radical selected from C C alkylene, phenylene, C -C cycloalkylene and the hydrocarbon radical remaining after the removal of the carboxylic acid groups from the dimer and trimer acids of C,;-C. diunsaturated fatty acids, and x is an integer from 2 to 4. The cross-linking can be accomplished by heating the polymer with one of the following agents or mixtures of agents which yield polycarboxylate polyanions:  
 1. quaternary ammonium salts of the polycarboxylic acids 2. a mixture of the polycarboxylic acid, certain lead compounds and quaternary ammonium halides 3.-. a mixture of an alkali metal salt of the polycarboxylic acid and a small amount of the quaternary ammonium salt of the polycarboxylic acid.  
 8 Claims, No Drawings CROSS-LINKING EPIHALOHYDRIN POLYMERS The present invention relates to cross-linking epihalohydrin polymers and to the polymers so cross-linked. More particularly, this invention relates to crosslinking epihalohydrin polymers with polycarboxylate polyanions.  
  Epihalohydrin polymers have been cross-linked, i.e., vulcanized, in the past using various agents, such as polyamines, urea, thiourea and certain heterocyclic compounds in combination with various metal compounds to produce elastomers that have numerous good attributes.  
  It has now unexpectedly been found that polymers and copolymers of epihalohydrins can be cross-linked with a polycarboxylate polyanion having the formula where R is a radical selected from the group consisting of C ,-C most preferably C C alkylene, phenylene, C C}, cycloalkylene and the hydrocarbon radical remaining after the removal of the carboxylic acid groups from the dimer and trimer acids of C C diunsaturated fatty acids, and X is an integer from 2 to 4.  
  Any solid polymer, homopolymer or copolymer of an epihalohydrin, as. for example, epichlorohydrin, epiiodohydrin. or epibromohydrin homopolymers, copolymers of two different epihalohydrins, or copolymers of an epihalohydrin with one or more other epoxides or oxetanes can be cross-linked in accordance with this invention. These polymers are readily prepared by the polymerization of epihalohydrins with, for example, organoaluminum compounds as catalysts. Particularly effective catalysts for the polymerization of epihalohydrins are alkylaluminum compounds that have been reacted with from about 0.2 to about 1 mole of water per mole of alkylaluminum compound. The polymers obtained by these catalysts may be essentially wholly amorphous or crystalline or they may be a mixture of the amorphous and crystalline polymers. Generally, the amorphous polymers provide the most rubbery vulcanizates, the crystalline polymers on vulcanization tending to be hard, brittle, and lacking in elasticity. These properties are, of course, useful in the case of relatively rigid molded articles which can be prepared by molding the compounded polymer and then curing to cross-link and set it. However, excellent rubbers are obtained by vulcanizing mixtures of amorphous and crystalline polymers. [n this case, the amount of the crystalline polymer is generally less than about -30% of the mixture.  
  When epihalohydrins are polymerized by the above process, polymerization takes place at least in major part through the epoxide linkage so that the product is a polyether containing halomethyl groups attached to the main polymer chain. The homopolymers are believed to have the following general formula where X is halogen. In the same way, when an epihalohydrin is copolymerized with one or more other epoxides or oxetanes (including other epihalohydrins), polymerization takes place through the epoxide or oxetane linkage even though other polymerizable groups may be present. Typical of epoxides and oxetanes that can be copolymerized with an epihalohydrin to produce a copolymer that can be cross-linked in accordance with this invention are the alkylene oxides such as ethylene oxide, propylene oxide, butene oxide, etc.; butadiene monoxide, cyclohexene oxide, vinyl cyclohexene oxide, epoxide ethers such as ethyl glycidyl ether, 2chloroethyl glycidyl ether, hexyl glycidyl ether, allyl glycidyl ether, etc.; trimethylene oxide (oxetane), alkyl substituted oxetanes, such as Z-ethyloxetane, 3- butyloxetane, 3,3-dimethyloxetane, etc.; haloalkyl substituted oxetanes such as 2-chloromethyloxetane, 3- iodopropyloxetane, etc.; alkoxy substituted oxetanes such as 2-ethoxyoxetane, 3-propoxyoxetane, etc.; alkoxyalkyl substituted oxetanes such as 2- butoxymethyloxetane, 3-hexoxymethyloxetane, etc.; haloalkoxy substituted oxetanes such as 2- bromobutoxyoxetane; 3-fluoromethoxyoxetane, etc.; haloalkoxyalkyl substituted oxetanes such as 2-chloroethoxymethyloxetane, 3-fluoromethoxymethyloxetane, etc. The copolymers will in general contain at least about 10% by weigth of an epihalohydrin monomer.  
  The polymers of an epihalohydrin that are crosslinked, i.e., vulcanized, in accordance with this invention. are high molecular weight solid polymers. Any homopolymer or copolymer that has a Reduced Specifid Viscosity (RSV) of at least about 0.2, i.e., a molecular weight of at least about 40,000, can be cross-linked with the agents of this invention to yield a polymer of increased tensile strength and modulus. The term RSV, which is a function of molecular weight, is used herein to designate the specific viscosity measured at C. on an a-chloronaphthalene solution of the polymer containing 0.1 g. per 100 ml. of solution divided by the concentration of the solution. Polymers having an RSV above about 0.2, and preferably above about 0.5, on cross-linking yield excellent general purpose specialty rubbers.  
  These epihalohydrin polymers generally contain a small amount (i.e., from about 0.1% to about 2% by weight) of anti-oxidant added at the time of their preparation. It may in some cases be desirable to add a small additional amount of antioxidant before or at the time of cross-linking the polymer. Exemplary of the most preferable antioxidants are phenyl-B-naphthylamine, di-B-naphthyl-p-phenylenediamine, syn-di-B-naphthylp-phenylenediamine, N-isooctyl-p-aminophenol, the reaction product of diphenylamine and acetone, polymerized trimethyldihydroquinolinc, 4,4-thio-bis(6- tert-butyl-m-cresol), the reaction product of crotonaldehyde and 3-methyl-6-tert-butylphenol, nickel -dibutyldithiocarbamate, the zinc salt of 2- mercaptobenzimidazole, etc.  
  Epihalohydrin polymers are cross-linked in accordance with this invention by heating a mixture of the polymer with one or more agents which yield polycarboxylate polyanions.  
  In one modification of this invention, the polymer is admixed and then heated with a quaternary ammonium salt of a polycarboxylic acid having the formula o Ndwi In another modification of this invention, the polymer is admixed and then heated with l) a polycarboxylic acid having the formula R-(-COOH),  
 where R and x are as defined above, (2) a lead compound selected from the lead salts of aromatic carboxylic acids, the lead salts of aliphatic carboxylic acids, the lead salt of carbonic acid, the lead salt of phosphorous acid, the lead salt of silicic acid and the lead oxides, and (3) a quaternary ammonium halide having the formula X&#39; N(R&#39;) where X is a halide radical selected from chloride, bromide and iodide and R is as defined above. it is believed that the polycarboxylic acid and quaternary ammonium halide when heated in the presence of the lead compound form the quaternary ammonium salt of the polycarboxylic acid, which in turn yields the polycarboxylate polyanion. Typical polycarboxylic acids that can be used in the above modification are malonic acid, succinic acid, adipic acid, pimelic acid, suberic&#39;acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,3,5- pentane tricarboxylic acid, terephthalic acid, isophthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, 1,3-cyclobutane dicarboxylic acid, 1,3- cyclopentene dicarboxylic acid, l,2,3,4-cyclopentane tetracarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 1,3,5-cyclohexane tricarboxylic acid, l,2,4,5- cyclohexane tetracarboxylic acid, 1,4-cycloheptane dicarboxylic acid, 1,3,5-cycloheptane tricarboxylic acid, 1,5-cyclooctane dicarboxylic acid, 1,5-cyclononane dicarboxylic acid, and the dimer and trimer acids prepared by the polymerization of unsaturated fatty acids, such as palmitolic acid, linoleic acid, eicosinic acid, etc. Typical quaternary halides that can be used in the above modification are methyltributylammonium iodide, tetrabutylammonium bromide, hexyltrimethylammonium bromide, tetramethylammonium bromide, tetraethylammonium chloride, octyltrimethylammonium bromide, cyclopentyltrimethylammonium bromide, cyclohexyldiethylmethylammonium bromide, dimethylmorpholinium iodide, and cyclononyltrimethylammonium iodide. Typical lead compounds that can be used in the above modification are dibasic lead phthalate, lead oleate, lead adipate, dibasic lead stearate, the lead salt of carbonic acid, the lead salt of phosphorous acid, the lead salt of silicic acid, lead monoxide and red lead oxide. The polycarboxylic acid and quaternary ammonium halide can be present in various molar ratios. However, for best results, a ratio of about one mole of quaternary ammonium halide per mole of carboxyl group will be used. The lead compound will be present in an amount of from about 0.1% to about 20% by weight based on the polymer.  
  In still another modification of this invention the polymer is admixed and then heated with l an alkali metal salt of a polycarboxylic acid having the formula RCOOM) where M is an alkali metal, such as lithium, sodium or potassium, and R and are as defined above, and (2) a relatively small amount of a quaternary ammonium salt of a polycarboxylic acid having the formula o Nm&#39;n).  
 where R, R and x are as defined above. It is believed that the quaternary ammonium salt helps to solubilize the alkali metal salt of the polycarboxylic acid in the polymer so that it may ionize forming the polycarboxylate polyanion. As little as 10 mole 7c of the quaternary ammonium salt, based on the total moles of polyanion cross-linkers (alkali metal salt plus quaternary ammonium salt), is effective. Generally, from about 10 mole 7: to about 50 mole of the quaternary ammonium salt, based on the total moles of polyanion cross-linkers will be used. It will be understood that even larger percentages of the quaternary ammonium salt can be used but no advantages will be obtained therefrom. Typical alkali metal salts of polycarboxylic acids that can be used in the above modification are disodium adipate,  
 disodium azelate, dipotassium malonate, dilithium sebacate, dipotassium azelate, the disodium salt of the dimer acid of linoleic acid, trisodium 1,3,5-pentanetricarboxylate, dipotassium terephthalate, dilithium phthalate, disodium l,4-cyclohexanedicarboxylate, and tripotassium l.3,5-cycloheptanetricarboxylate. Typical quaternary ammonium salts of polycarboxylic acids are listed above.  
  The amount of polycarboxylate polyanion used in the cross-linking process of this invention will vary, depending upon the specific polycarboxylate polyanion being employed and the amount of cross-linking required. The amount of cross-linking required to produce a vulcanized epihalohydrin elastomer (i.e.. rubber) will naturally be less than the amount required to produce a hard plastic. in general, from about 0.0025 gram mole to about 1.0 gram mole, most preferably from about 0.0075 gram mole to about 0.02 gram mole, of the polyanion per 100 grams of polymer will be used for cross-linking in accordance with this invention.  
  As indicated above, cross-linking in accordance with this invention is initiated by heating the polymer in admixture with one or more agents which will yield the necessary amount of polycarboxylate polyanion. Various temperatures. below the decomposition point of the polymer. can be used. In general, the cross-linking temperature will be in the range of from about 200F. to about 400F. The amount of time required to effect cross-linking will vary inversely with the temperature. In general, the amount of time will be from about 1 minute to about 60 minutes.  
  ln addition to the cross-linking agents (i.e., polycarboxylate polyanion producers) it may be desirable to also admix with the polymer one or more metallic stabilizers. particularly lead stabilizers. The most preferred stabilizers are the lead compounds recited above, particularly red lead oxide. Therefore, it may be desirable to add at least a small amount, i.e.. from about 0.2% to about 5.0% by weight. based on the weight of the polymer. of a lead stabilizer. although even larger amounts may be used. it will. of course. be recognized that there are cases in which a metallic stabilizer is not desired and excellent vulcanizates can be obtained without it.  
  Besides the cross-linking agents and metallic stabilizers. still other ingredients may be incorporated. ln certain cases. it may be desirable to use one or more of the additives commonly used in rubber vulcanizates, such as extenders. fillers, pigments. plasticizers and softeners. The presence of a filler and, in particular, carbon black. may be beneficial, as in rubber compounding. Obviously, there are many cases in which a filler, extender. plasticizer, etc.. is not required or desired and excellent results are achieved when only the crosslinking agent is used.  
  The cross-linking agents (stabilizers and other additives if they are used) can be incorporated or ad mixed with the polymer in any desired fashion; for example. they can be uniformly blended with a polymer by simply milling on a conventional rubber mill or mixing in a Banbury mixer. By this means, the agents are uniformly distributed throughout the polymer and uniform cross-linking is effected when the blend is subjected to heat. Other methods of admixing the crosslinking agents with the polymer will be apparent to those skilled in the art.  
  In addition to improving the physical properties of epihalohydrin polymers, cross-linking with polycarboxylate polyanions has been found to greatly increase the adhesion of epihalohydrin polymers to polyesters, particularly poly(ethylene terephthalate). In the past, the use of polyester cords or fibers to reinforce epihalohydrin rubber articles was plagued by poor adhesion between the polyester and the rubber. Now it has been found that polyester reinforced epihalohydrin rubber having good adhesion between the epihalohydrin rubber and polyester can be prepared by cross-linking the rubber with a polycarboxylate polyanion while in contact with the polyester reinforcement. This improvement can be accomplished using various methods. One method which may be used is to coat the polyester cord or fiber with a solution of the epihalohydrin rubber and an agent which yields polycarboxylate polyanions, remove the solvent and heat to effect crosslinking. The resulting rubber coated cord or fiber can then be embedded in epihalohydrin rubber to yield articles having excellent reinforcing properties.  
  The following examples will illustrate the process of cross-linking epihalohydrin polymers in accordance with this invention and the vulcanizates so obtained. All parts and percentages are by weight unless otherwise indicated.  
 GENERAL PROCEDURE FOR PREPARATION OF VULCANIZATES In all of the examples, polymer stocks are made up by mixing on a two-roll mill (rolls maintained at about 150F.) one hundred parts of dry polymer with the specified cross-linking agents and any other additives for about ten minutes. The polymer is first added to the mill and when it bands, the other ingredients are added in the general order: lubricant, followed by filler, followed by antioxidant, followed by metallic stabilizer, followed by cross-linker. Where recipes indicate omissions, the order of addition is merely advanced. The resulting polymer stocks are cross-linked by one of two methods:  
  l. in an oscillating disk rheometer (as described in ASTM D-2705-68T) at a temperature of 320F. The extent of cross-linking is indicated by the inch-pounds of torque required to twist the sample. Completion of cross-linking is characterized by the maximum inchpounds of torque recorded when plotted against time.  
  2. ln two-part steel molds under 100 p.s.i. minimum pressure. Specimen thickness is approximately mils. The properties of the resulting vulcanizate are given in terms such as modulus, tensile strength, elongation at break, Shore hardness and compression set.  
 EXAMPLES 1 AND 2 These examples illustrate cross-linking an epihalohydrin polymer with polycarboxylate polyanions resulting from a polycarboxylic acid, a lead compound and a quaternary ammonium halide.  
  In each example, epiehlorohydrin homopolymer having an RSV of approximately 1.8 is milled and crosslinked in two-part steel molds for 30 minutes at 320F. with azelaic or isophthalic acid and tetrabutylammonium bromide. The amounts of the ingredients (by parts) in the formulation and the physical properties of the vulcanizates are tabulated below:  
 Examples Comparators Ingredients 1 2 a h c d Polyepichloro- I 1 ()0 I00 I00 I00 I ()0 hydrin Sorbitan monol l l l l l stearatc (Lubricant) Fast extruding O 5O 50 50 50 50 furnace black Nickel dibutyl l l l l l l dithiocarhamate (Antioxidant) Red lead .5 5 5 Azelaie acid 2 2 2 lsophthalic acid l Tetrabutylammonium 4 3.2 4 4 bromide Physical Properties Modulus at 100% (p.s.i.) l 2 a b c d Unagcd 780 770 100 I00 100 l()() Aged* 1730 1945 l()() l ()0 l ()0 I00 Tensile Strength (p.s.i.l Unagcd 1835 I640 100 l()() 100 I00 Agcd* I945 I945 100 100 l()() 100 Maximum Elongation 7!) Unaged 75 280 400 400 400 400 Agcd* 1 l()() 400 400 400 400 Shore A Hardness Unaged 72 7O 27 27 27 27 Aged* 82 8. 25 25 25 Compression Set (/1) 70 hours at 257F. 64 92 I00 I00 lUO 100 *3 days at 3(|2F. in air.  
 EXAMPLE 3 -Continued This example illustrates cross-linking an epihalohyg Ul&#39;l&#39;ltlC UL drin copolymer with a polycarboxylate polyanion re- NickcldiLbum 1 1 sulting from a polycarboxylic acid, a lead compound dithroca amatc and a quaternary ammonium halide. fmgf&#39; igg 75 An epichlorohydrin--ethylene oxide copolymer hav- Azelaic acid I ing an RSV of approximately 3.0 and containing epii 31 chlorohydrin and ethylene oxide in a mole ratio of 40 :50 is milled and cross-linked in a two-part steel mold at 320F. for 30 minutes with azelaic said, red lead and tetrabutylammonium bromide. The amounts of the ingredients (by parts) in the formulation and the EXAMPLES 4-11 These examples illustrate cross-linking an epihalohydrin polymer with polycarboxylate polyanions resulting physical properties of the vulcanizate are tabulated be- 45 from a p y y i acid, a lead mpoun and a quaternary ammonium halide.  
 low:  
  In each example epichlorohydrin homopolymer hav- Example 3 Comparator ing an RSV of approximately 1.8 is milled and crosslinked in two-part steel molds for minutes at 320F. Epichlorohydrln- I00 1 ()0 ethylene Oxide 50 The amounts of the ingredients (by parts) in the formup b&#39; lation and the physical properties of the vulcanizate are Sorbltan monostcaratc l l b d b l (lubricant) m u ate e Examples Comparator Ingredients 4 .5 o 7 9 l() l l A Polyepichlorohydrin I00 I00 I00 100 I00 I00 l()() IOU Sorhitan monostearate l l l l l l l l l Fast extruding furnace black 0 0 0 0 0 0 .50 0 0 Nickel dihutyl dithioearhamate &#39;l l l l l l I l 1 Red lead 7.5 7. 7 7 5 7 5 7.5 7.. 7.5 7 5 l.-l-(&#34; \&#39;clohexane dicarboxylic acid 1.7 Z0 1.7 L7 3-(arhoxy-3-melhyl adipic acid l. l3.3.-l-()&#39;clopentune tctracarhoxylic acid 2.5 5 ll 1U Tetrahutylammonium bromide 3.2 3 2 3.2 6.4 6.4 20 3.2 &#39;l&#39;etrabutylammonium chloride 2.8 3.7  
 Tetrnhut lamnionium iodide Physical Properties 4 5 6 7 8 9 I I I A Modulus at I00)? (p.s.i.) Lfi eed 930 850 800 I250 I850 825 I140 I I50 I340 I200 I450 I700 I600 I I40 I500 300 ensile Strength (p.s.i Unaged 2250 I950 2000 2450 I900 2 I 00 2150 2420 200 Aged* 2 I ()0 2300 2200 2200 I600 I900 2300 2200 300 Maximum Elongation (/i) Ln&#39;iged 370 420 400 230 I20 IO 4 I0 250 400 Aged 200 220 210 I50 100 I0 200 I80 380 Shore A Hardness L&#39;naged 70 68 68 84 I00 I00 68 75 30 Aged 76 74 75 89 I00 I00 73 80 34 Compression Set (&#34;2) 70 hours at 302F. 78 85 80 75 75 85 75 70 I00 3 days al 302 1 in air.  
 EXAMPLES I2 AND 13 These examples illustrate cross-linking an epihalohydrin polymer with a polycarboxylate polyanion resulting from a quaternary ammonium salt of a polycarboxylie acid.  
  In each example. the polyepichlorohydrin described in Examples I and 2 is milled and cross-linked in twopart steel molds for 30 minutes at 320F. with bis(tetramethylammonium) azelate. The amounts of the ingredients (by parts) in the formulations and the physical properties of the vulcanizates are tabulated below:  
  Examples Ingredients 12 Comparator Polyepichlorohydrin I00 I00 I00 Sorbitan monostearate l I l (lubricant) Fast extruding 50 50 50 furnace black Nickel dibutyl I I I dithioearbamate (antioxidul&#39;it) (a() (stabilizer) 5 5 Iiisl teiramethylammonium) 3.6 3.2  
 azelate Physical Properties Modulus at 1009 (p.s.i.) l&#39;naged I035 H4O I00 Aged 660 I4 I 0 I00 Tensile Strength (p.s.i.)  
 2070 2040 l ()0 980 I960 I00 76 86 28 72 82 32 Compressison Set (&#34;i l 70 hours at 257 F. 34 I00 70 hours at 302Fi X6 50 I00 2 days at KIII&#39;I III air.  
 EXAMPLE 14 This example illustrates cross-linking an epihalohydrin polymer with a polycarboxylate polyanion resulting from a quaternary ammonium salt ola polycarbox- \&#39;lie acid.  
  The poIyepichlorohydrin described in Examples I and 2 is milled and cross-linked in two-part steel molds for minutes at 320F. with bisttetrabutylammonium) azelate. The amounts of the ingredients (by parts) in the formulation and the physical properties of the vulcanizates are tabulated below:  
 Ingredients Example l4 Comparator Polyepichlorohyd rin I00 I 00 Sorbitan monostearate l I (lubricant) Fast extruding 50 50 furnace black Nickel dibutyl dithio- I I carbamate (antioxidant) *3 days at 302F. in air.  
 EXAMPLES 1521 These examples illustrate cross-linking an epihalohydrin polymer with polycarboxylate polyanions resulting from quaternary ammonium salts of polycarboxylic acids.  
  In each example, the polyepichlorohydrin described in Examples 1 and 2 is milled and cross-linked in an oscillating disk rheometer with various quaternary ammonium salts. In each sample. I00 parts of the polymer is compounded with 1 part of sorbitan monostearate (lubricant), 50 parts of fast extruding furnace black. I part of nickel dibutyldithiocarbamate (antioxidant) and 0.01 mole of quaternary ammonium salt per grams of polymer. The specific quaternary ammonium salt used and the inch-pounds of torque required to twist the sample after cross-linking 30 minutes at 320F. is tabulated below:  
 Polyester Cord Polyester cord is placed between two sheets of the above polyepichlorohydrin rubber formulation and vulcanized in a two-part mold for 15 minutes at 320F. Specimens having an H shape are cut from the resulting cord reinforced sheets and tested for force required to separate specimen (American Standard Testing Method No. D2l38-67) and to determine if the rubber adheres to the cord. The specific polyester cords used and the results of the tests are tabulated below:  
 Example 28 Comparator H-test Rubber H-test Rubber (lbs. of force) Adheres (lbs. of force) Adhcres Polyethyleneterephthalate&#39; 40 yes 18 no High earboxyl polyethyleneterephthalate 37 Yes l8 no Polyt l.-l&#39;c \&#39;elohex \&#39;lenedimethylenete rephthalate&#34; 42 yes 18 no Sold by Du Pont and designated &#39;Mx. &#34;&#39;Sold by (&#39;elanese under the trade name &#34;Fortrel&#34;. &#34;Sold by Eastman Kodak under the trade name Kodel ll&#34;.  
 EXAMPLES 22-27 These examples illustrate cross-linking an epihalohydrin polymer with polycarboxylate polyanions resulting from an alkali metal salt of a polycarboxylic acid and a quaternary ammonium salt of a polycarboxylic acid.  
  In each example. the polyepichlorohydrin described in Examples 1 and 2 is milled and cross-linked in an os- What I claim and desire to protect by Letters Patent 1. The process of cross-linking a polymer of an epihalohydrin which comprises heating said polymer in the presence of from about 0.0025 gram mole to about 1.0 gram mole per 100 grams of polymer of at least one agent which yields a polycarboxylate polyanion having the formula cillating disk rheometei&#39; with various alkali metal and quaternary ammonium salts of azelaic acid. The amounts of the ingredients (by parts) in the formula- 0 tion and the inch-pounds of torque required to twist the sample after cross-linking 30 minutes at 320F. is tabu- T K e lated below: 0  
  Exam les C 2 t Ingredients 22 23 2 p 2. 26 27 it m Polyepichlorohydrin I00 I00 I00 I00 I00 I00 100 Sorbttan monostearate l l l l l l 1 Fast extruding 50 S0 50 50 50 50 furnace black Nickel dibutyldithiocarbamate l l l l l l l Red lead 5 5 5 5 5 5 5 Dipotassium azelate 0.6 0.9 l. 3.0 3.0 2.2 Disodium azelate 1.6 Bist tetrabutylammoniuml l.4 1.4 l. 0.9 0.9 l .4  
  azelate Mole &#39;1; of quaternary 50 40 25 10.5 ,l() 25 ammonium salt Torque (inch-pounds) 92 92 l0) 84 80 X4 in EXAMPLE 28 where R is a radical selected from the group consisting This example illustrates the bonding of an epihalohydrin polymer toa&#39;fpolyester using aquaternary ammot nium salt of polycarboxylic-acidq The poly&#39;ep&#39;ichlorohydrin described in Examples l and 2 is milled&#39;with the following ingredients Example 28 azelare of phenylene, alkylene. cycloalkylene and the hydrocarbon radical remaining after the removal of the carboxylic acid groups from the dimer and trimer acids of diunsaturated fatty acids and is an integer from 2 to 4 2. The process of claim 1 wherein the polycarboxylate polyanion is formed in situ from a mixture of l. a polycarbox&#39;ylic acid having the formula where R is a radical selected from the group consisting 13 2. about one mole per mole of carboxyl group of a quaternary ammonium halide having the formula X N( R where X is a halide radical and R is a hydrocarbon group selected from alkyl and cycloalkyl, and  
 3. from about 0.1 to about 20% by weight based on the polymer of a lead compound selected from the lead salts of aromatic carboxylic acids. the lead salts of aliphatic carboxylic acids, the lead salt of carbonic acid. the lead salt of phosphorous acid, the lead salt olsilicic acid and the lead oxides.  
  3. The process olelaim 2 wherein the polycarboxylic acid is azelaic acid and the quaternary ammonium halide is tetrabutylammonium bromide.  
  4. The process of claim I wherein the polycarboxylate polyanion is formed in situ from a quaternary ammonium salt of a carboxylic acid having the formula 0 Nt &#39;a where R is a radical selected from the group consisting of phenylene. alkylene, cycloalkylene. and the hydrocarbon radical remaining after the removal of the carboxylic acid groups from the dimer and trimer acids of R-(-COOM wherein R is a radical selected from the group consisting of phenylene, alkylene, cycloalkylene and the hydrocarbon radical remaining after the removal of the carboxylic acid groups from the dimer and trimer acids of diunsaturated fatty acids, M is an alkali metal and .r is an integer from 2 to 4. and  
 2. from about 10 mole to about mole 71, based on the total moles of polyanion cross-linkers, of a quaternary ammonium salt ofa polycarboxylic acid having the formula where R is a radical selected from the group consisting of phenylene, alkylene, cycloalkylene and the hydro-- carbon radical remaining after the removal of the carboxylic acid groups from the dimer and trimer acids of diunsaturated fatty acids, R is a hydrocarbon group selected from alkyl and cycloalkyl, and x is an integer from 2 to 4.  
  8. A cross-linked polymer of an epihalohydrin prepared by heating a solid polymer of an epihalohydrin having a reduced specific viscosity of above about 0.2 in the presence of at least one agent which yields a polycarboxylate polyanion having the formula where R is a radical selected from the group consiting of phenylene, alkylene, cycloalkylene and the hydrocarbon radical remaining after the removal of the carboxylic acid groups from the dimer and trimer acids of diunsaturated fatty acids, and .r is an integer from 2 to 4.  
  UNITED STATES PATENT OFFICE CERTIFICATE ()F CORRECTION PATENT NO, 3,875,122  
 DATED April 1, 1975 INVENTOR(S) Joseph E. Mirolli It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 In the abstract, line 2 of printed patent;  
 &#34;polycarboxyplate&#34; should read --polycarboxylate-- Column ,8, line 40 of printed patent; Page 14 of spec. 7  
 Complete table missing, see attached table Column 9, line 33 of printed patent; No. &#34;2&#34; missing under Examples Column 14, line 39 (in the claims) of printed patent;  
 &#34;consiting&#34; should read --consisting- Patent NO- Dated 9 Joseph E. Mirolli Page 2 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 Physical Properties Example 3 Comparator iodulus at 100% (p.s.i.)  
 Unagec&#39;i 51s 10o Aged* 780 300 Tensile Strength (p.s.i.)  
 Unaged 1635 100 Aged* 825 300 Maximum Elongation Unaged 430 400 Aged* 105 800 Shore A Hardness Wm *3 days at 302F. in air.  
 Signed and sealed this 27th day of May 1975.  
 (SEAL) Attest C. MARSHALL DANN f Patents RUTIi C. MAQOR Commissioner 0 Attesting Officer and Trademarks F ORM FO-105C 10-69) USCOMM-DC 60376-5 69 u.s GOVERNMENT PRINTING OFFICE: a 69 93 o