CA2264803A1 - Aqueous dispersions - Google Patents

Abstract

Aqueous dispersion of polymers is provided which comprises: (a) a first cationic water-soluble or water-swellable polymer; and (b) at least one second water-soluble polymer different from said first polymer; and (c) a kosmotropic salt; and (d) a chaotropic salt, wherein the amounts of said (b), and (d) are such that a homogeneous composition is obtained in the absence of said (b). Process to form an aqueous dispersion. Method for dewatering a suspension of dispersed solids and method to produce clarified water using said dispersion.

Description

1015202530CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/ 16647Aqueous DispersionsBackground of the inventionThis invention relates to aqueous dispersions comprised of water-soluble polymers,processes for making said dispersions, and methods of using said dispersions in watertreating, dewatering, water clarification, papermaking, oil field, soil conditioning, foodprocessing, mineral processing, and biotechnological applications.U.S. Patent No. 4,380,600 discloses a process for producing an aqueous dispersionof water-soluble polymers. The aqueous dispersion may contain inorganic salt. However,the aqueous dispersions exemplified therein have disadvantageously high bulk viscosities.U.S. Patent No. 4,673,704 and EP 0 170 394 A2 disclose products comprised ofparticles above 20 microns in size of a high molecular weight polymer gel interconnectedby a continuous phase that is an aqueous solution of an equilibrating agent that holds thewater content of the particles in equilibrium with the water content of the aqueous phaseand that prevents substantial agglomeration of the particles in the fluid product. Althoughthese references are entitled “Aqueous Polymer Dispersions,” the products disclosed thereinare distinguished trom the aqueous dispersions of U.S. Patent No. 4,380,600 and from theaqueous dispersions of the instant invention in that the particles of U.S. 4,673,704 and EP0 170 394 A2 are not generally held suspended in a continuous matrix of the aqueousphase but instead generally rest substantially in contact with one another but slide over oneanother. A process for dispersing the polymer gel into an aqueous solution of anequilibrating agent and working the polymer while in that medium is disclosed in U.S. PatentNo. 4,778,836 and EP 0 169 674 B1. Also, U.S. Patent No. 4,522,968 discloses a processfor dispersing certain powdered water-soluble homopolymers or copolymers in an aqueoussolution containing a polymer of ethylene oxide and/or propylene oxide.U.S. Patent Nos. 4,929,655 and 5,006,590 disclose processes for preparing aqueousdispersions of water-soluble polymers by polymerizing benzyl-containing monomers in thepresence of an organic high molecular multivalent cation and a multivalent anionic salt. Thebenzyl group-containing monomer may be replaced by a hydrophobic alkyl group-containingmonomer as in EP 0 525 751. Numerous references concern these and similar polymers,e.g. U.S. 5,332,506; 5,332,507; 5,330,650: 5,292,793, 5,435,922; 5,466,338; EP 0 595 156A1; EP 0 630 909 A1; EP 0 657 478 A2; EP 0 629 583 A2; EP 0 617 991 A1, EP 0183466 B1, EP 0 637 598 A2; EP 0 717 056 A2; JP 61-6396; JP 61-6397; JP 61-6398; JP 62-262799; JP 64-15130; JP 2-38131; JP 62 15251; JP 61-138607; Hei 6-329866; and JP 62-1101520253035CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647100548. Although some of the aqueous dispersions in these references have relatively lowbulk viscosities, the need to include special monomers containing aromatic or hydrophobicalkyl groups in order to render the polymer insoluble in salt solution may bedisadvantageous because the special monomers may be expensive and dilutive of thepolymer effect in a specific application.The effect of salts on the solubility of various substances in aqueous solution is welldiscussed in the scientific literature. The “Hofmeister” series ranks anions according to theirability to increase or decrease the solubility of substances in water. Although positions in theranking may vary slightly, depending on the substance, a generally accepted ranking of theanions is:Salting-out 8042' ~ HPO42‘ > F‘ > Cl" > Br’ > l‘ ~ CIO4‘ > SCN' Salting-in(kosmotropic) (chaotropic)Kosmotropic salts generally decrease the solubility of substances in water. For instance, theHofmeister ranking apparently guided the choice of salts for precipitating cationic water solublepolymers, containing hydrophobic groups, in U. S. Patent Nos. 4, 929,655 and 5,006,590, aswell as EP 0 630 909 A1. EP 0 525 751 A1, and EP 0 657 478 A2, as evidenced by their useof strongly kosmotropic salts containing sulfate and phosphate anions. On the other hand,chaotropic salts generally increase the solubility of substances in water.There are numerous means known to those skilled in the art for determining whethera particular salt is kosmotropic or chaotropic. Representative salts which contain anions suchas sulfate, fluoride, phosphate, acetate, citrate, tartrate and hydrogenphosphate arekosmotropic. Representative salts which contain anions such as thiocyanate, perchlorate,chlorate, bromate, iodide, nitrate and bromide are chaotropic. The chloride anion is generallyconsidered to be at about the middle of the Hofmeister ranking, being either weakly chaotropicor weakly kosmotropic, depending on the particular system. In the instant invention, althoughoccasionally chaotropic, inorganic salts which contain the chloride anion tend to be kosmotropic.Small amounts of sodium thiocyanate, for instance about 0.1% by weight, on total, havebeen reported to be useful as stabilizers for polymer dispersions as in EP 0 657 478 A2, where(NH,,)2SO,, was used to deposit the polymer. Sodium thiocyanate and sodium iodide have beenreported to be useful as stabilizers for hydroxylamine-containing water-soluble polymer systems,as in EP 0 514 649 A1. U.S. 3.234.163 teaches that small amounts of thiocyanate salts,21015202530CA 02264803 1999-03-04wo 98/14405 PCT/US97/16647preferably 0.1 to 1 percent, based on the weight of the polymer, are useful for stabilizingpolyacrylamide solutions.The Hofmeister ranking has been observed in solutions of high molecular weight, water-soluble polymers. For instance, the effect of various salts on the solubility of synthetic, water-soluble polymers was explored by Shuji Saito, J. Polym. Sci.: Pt. A, Vol. 7, pp. 1789-1802(1969). This author discussed the effect of various anions or polymer solubility and stated"This anionic order seems to be independent of the type of counter cations and is in line withHofmeisters Iyotropic series for anions." Similarly, in M. Leca, Polymer Bulletin, Vol. 16, pp.537-543, 1986, the viscosity of polyacrylamide, as detennined in 1N solutions of various salts,was found to increase in the order HPO,,2' < H20 < Br < N03‘ < l‘ = Bros‘ < ClO3,' = SON‘. Theviscosities were reported to be higher in more chaotropic salt solutions than in less chaotropic,or kosmotropic, salt solutions. Certain novel cationic polyelectrolytes, termed ionene polymers,were reported (D. Casson and A. Rembaum, Macromolecules, Vol. 5, No. 1, 1972, pp. 75-81)to be insoluble in either 0.4 M potassium iodide or 0.4 M potassium thiocyanate. It has alsobeen reported (W-F. Lee and C—C. Tsai, J. Appl. Polym. Sci., Vol. 52, pp. 1447-1458, 1994) thatpoly(trimethyl acrylamido propyl ammonium iodide) did not dissolve in 0.5 M Na2ClO,, or 0.5M NaNO3.Certain anionic organic salts, such as hydrotropes and surfactants, also tend to increasethe solubility of substances in water. However, poly(allylammonium chloride) was reported (T.ltaya et al., J. Polym. Sci., Pt. B: Polym. Phys., Vol. 32, pp. 171-177, 1994, and references 3,5 and 6 therein; also Macromolecules, Vol 26, pp. 6021-6026, 1993) to precipitate in solutionscontaining the sodium salt of p-ethylbenzenesultonate, p-propylbenzenesulfonate ornaphthalenesulfonate. Po|y(4—viny| pyridine) quatemized with butyl chloride andpoly(allylammonium chloride) were reported (M. Satoh, E. Yoda, and J. Komiyama,Macromolecules, Vol. 24, pp. 1123-27, 1991) to precipitate in solutions of Nal and also insolutions containing the sodium salt of p—ethylbenzenesulfonate, respectively. Compositionscomprising sulphonated hydrocarbon surfactants and hydrophilic cationic polymers weredisclosed in U.S. Patent No. 5,130,358. Mixtures of chaotropic salts, or anionic organic salts,and kosmotropic salts may be used to precipitate cationic polymers as in U.S. Application SerialNo. (attorney docket No. 96052), filed even date herewith.Aqueous dispersions of water-soluble polymers are disclosed in U.S. 5,403,883;5,480,934; 5,541,252; EP 0 624 617 A1: EP 0 573 793 A1; and WO 95/11269. A problemremains in that the aqueous dispersions exemplified in these references still have relativelyhigh bulk viscosities.1015202530CA 02264803 1999-03-04wo 93/14405 PCT/US97/16647A process for preparing crosslinked copolymer beads from water-soluble monomersin an aqueous solution containing an inorganic salt and a dispersant is disclosed in U.S.5,498,678 and EP 0 604 109 A2.emulsions are disclosed in Hei 7—62254 and Hei 6-25540. The addition of a nonionicMixtures of aqueous dispersions and water-in-oilsurfactant and an oleaginous liquid to an aqueous dispersion to maintain flowability isdisclosed in U.S. Patent No. 5,045,587. Mixtures of cationic polymers are disclosed in Sho-52-71392 and homogeneous blends of water-soluble polymers are disclosed in U.S. PatentNo. 4,835,206 and EP 0 262 945 B1. Bimodal cationics for water clarification are disclosedin U.S. Patent Nos. 4,588,508 and 4,699,951. Blends of water-in-oil polymer emulsions aredisclosed in U.S. Patent Application Serial No. 08/408,743.in spite of the effort to make satisfactory aqueous dispersions, the problem remainsof producing aqueous dispersions of high molecular weight water soluble polymers thathave advantageously low bulk viscosities, high active solids content, minimal quantities ofdilutive material, and that dissolve readily and can be prepared with a broad range ofcationicity.Summary of the InventionThis problem is solved in the present invention by providing novel aqueousdispersions of high molecular weight water-soluble or water-swellable polymers, as well asprocesses for making and methods of using said aqueous dispersions. Accordingly, anaqueous dispersion of polymers is provided which comprises: (a) a first cationic water-soluble or water-swellable polymer; and (b) at least one second water-soluble polymerdifferent from said first polymer; and (c) a kosmotropic salt; and (d) a chaotroplc salt,wherein the amounts of said (b), (c) and (d) are such that a homogeneous composition isobtained in the absence of said (b). in another embodiment, an aqueous dispersion ofpolymers is provided which comprises: (a) a first cationic water-soluble or water-swellablepolymer; and (b) at least one second water-soluble polymer different from said first polymer;and (c) a kosmotropic salt; and (d) an anionic organic salt, wherein the amounts of said (b),(C) and (d) are such that a homogeneous composition is obtained in the absence of said(b)-In another embodiment, an aqueous dispersion of polymers is provided which iscomprised of (a) a discontinuous phase containing polymer that is comprised predominatelyof a first cationic water-soluble or water-swellable polymer having at least one recurring unitof the formula (I),101520CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647wherein R, is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylenegroup having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl,ethyl, or propyl group, R4 is a methyl, ethyl or propyl group, X is a counterion, and R2, R3,and R4 together contain a total of at least 4 carbon atoms; and (b) at least one secondwater-soluble polymer different from said first polymer.in another embodiment, an aqueous dispersion of polymers is provided whichcomprises: (a) a first cationic water-soluble or water-swellable polymer having at least onerecurring unit of the formula (I), wherein R, is H or CH3, A is O or NH, B is an alkylene orbranched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl,or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is an alkyl or substituted alkylgroup having from 1 to 10 carbons, or an aryl or substituted aryl group having from 6 to 10carbons, X is a counterion, and R2, R3, and R4 together contain a total of at least 4 carbonatoms; and (b) at least one second water-soluble polymer different from said first polymer,wherein a homogeneous composition is obtained in the absence of said (b).in another embodiment. a process for making an aqueous dispersion of polymersis provided which comprises polymerizing vinyl-addition monomers to form an aqueousdispersion comprised of a first cationic water-soluble or water-swellable polymer, whereinsaid polymerizing is carried out in the presence of an aqueous composition comprised of(a) at least one second water-soluble polymer different from said first polymer; (b) akosmotropic salt; and (c) a chaotropic salt, wherein the amounts of said (a), (b) and (c) aresuch that a homogeneous composition is obtained if said polymerizing is carried out in theabsence of said (a).101520CA 02264803 1999-03-04wo 93/14405 PCTIUS97/16647In another embodiment, a process for making an aqueous dispersion of polymersis provided which comprises polymerizing vinyl-addition monomers to form an aqueousdispersion comprised of a first cationic water-soluble or water-swellable polymer, whereinsaid polymerizing is carried out in the presence of an aqueous composition comprised of(a) at least one second water-soluble polymer different from said first polymer; (b) akosmotropic salt; and (C) of an anionic organic salt, wherein the amounts of said (a), (b) and(c) are such that a homogeneous composition is obtained if said polymerizing is carried outin the absence of said (a).In another embodiment, a process for making an aqueous dispersion of polymersis provided which comprises polymerizing vinyl-addition monomers comprised of at leastone monomer of the formula (II) to form an aqueous dispersion comprised of a first cationicwater-soluble or water-swellable polymer,wherein R, is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylenegroup having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl,ethyl, or propyl group, R4 is a methyl, ethyl or propyl group, X is a counterion, and R2, R3,and R4 together contain a total of at least 4 carbon atoms; and wherein said polymerizingis carried out in the presence of an aqueous composition comprised of at least one secondwater-soluble polymer different from said first polymer.in another embodiment, a process for making an aqueous dispersion of polymersis provided which comprises polymerizing vinyl-addition monomers comprised of at leastone monomer of the formula (ll) to form an aqueous dispersion comprised of a first water-6101520253035CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647soluble or water-swellable cationic polymer, wherein R, is H or CH3, A is O or NH, B is analkylene or branched alkylene or oxyaikylene group having from 1 to 5 carbons, R2 is amethyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is an alkyl orsubstituted alkyl group having from 1 to 10 carbons, or an aryl or substituted aryl grouphaving from 6 to 10 carbons, X is a counterion, and R2, R3, and R4 together contain a totalof at least 4 carbon atoms; and wherein said polymerizing is carried out in the presence ofan aqueous composition comprised of an amount of at least one second water-solublepolymer different from said first polymer; and wherein said amount of said second polymeris such that a homogeneous composition is obtained if said polymerizing is carried out inthe absence of said second polymer.in another embodiment, a process for blending two or more aqueous dispersionsis provided, comprising intermixing (a) a first aqueous dispersion of a water-soluble orwater-swellable polymer with (b) a second aqueous dispersion of a water-soluble or water-swellable polymer, wherein said (a) is different from said (b), to form a third aqueousdispersion.in another embodiment, a method of dewatering a suspension of dispersed solidsis provided which (a) intermixing an aqueous dispersion of polymers, or aqueous admixturethereof, in an amount effective for dewatering, with a suspension of dispersed solids, and(b) dewatering said suspension of dispersed solids, said aqueous dispersion beingcomprised of (i) a first cationic water-soluble or water-swellable polymer; and (ii) at leastone second water-soluble polymer different from said first polymer; and (iii) a kosmotropicsalt; and (iv) a chaotropic salt, wherein the amounts of said (ii), (iii) and (iv) are such thata homogeneous composition is obtained in the absence of said (ii).In another embodiment, a method of dewatering a suspension of dispersed solidsis provided which comprises (a) intermixing an aqueous dispersion of polymers, or aqueousadmixture thereof, in an amount effective for dewatering, with a suspension of dispersedsolids, and (b) dewatering said suspension of dispersed solids, said aqueous dispersionbeing comprised of (i) a first cationic water-soluble or water-swellable polymer; and (ii) atleast one second water-soluble polymer different from said first polymer; and (iii) akosmotropic salt; and (iv) an anionic organic salt, wherein the amounts of said (ii), (iii) and(iv) are such that a homogeneous composition is obtained in the absence of said (ii).In another embodiment, a method of dewatering a suspension of dispersed solidsis provided which comprises (a) intermixing an aqueous dispersion of polymers, or aqueousadmixture thereof, in an amount effective for dewatering, with a suspension of dispersedsolids, and (b) dewatering said suspension of dispersed solids, said aqueous dispersion7101520253035CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647being comprised of (i) a discontinuous phase containing polymer that is comprisedpredominately of a first cationic water-soluble or water-swellable polymer having at leastone recurring unit of the formula (I), wherein R, is H or CH3, A is O or NH, B is an alkylene"or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl,or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is a methyl, ethyl or propyl group,X is a counterion, and R2, R3, and R4 together contain a total of at least 4 carbon atoms;and (ii) at least one second water-soluble polymer different from said first polymer.In another embodiment, a method of dewatering a suspension of dispersed solidsis provided which comprises (a) intermixing an aqueous dispersion of polymers, or aqueousadmixture thereof, in an amount effective for dewatering, with a suspension of dispersedsolids, and (b) dewatering said suspension of dispersed solids, said aqueous dispersionbeing comprised of (i) a first cationic water-soluble or water-swellable polymer having atleast one recurring unit of the formula (I), wherein R, is H or CH3, A is O or NH, B is analkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is amethyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is an alkyl orsubstituted alkyl group having from 1 to 10 carbons, or an aryl or substituted aryl grouphaving from 6 to 10 carbons, X is a counterion, and R2, R3, and R4 together contain a totalof at least 4 carbon atoms; and (ii) at least one second water-soluble polymer different fromsaid first polymer, wherein a homogeneous composition is obtained in the absence of said(ii).In another embodiment, a process for producing substantially dry water-soluble orwater-swellable vinyl-addition polymer particles is provided which comprises (a) spray-dryinga vinyl-addition polymer-containing aqueous dispersion into a gas stream with a residencetime of about 8 to about 120 seconds and at an outlet temperature of about 70° C to about150° C and (b) collecting resultant polymer particles.In another embodiment, substantially dry water-soluble or water-swellable polymerparticles are provided which are comprised of (a) a first cationic water-soluble or water-swellable polymer; and (b) at least one second water-soluble polymer different from saidfirst polymer; and (c) a kosmotropic salt; and (d) a chaotropic salt, wherein about 90% ormore of said polymer particles each individually contains both said (a) and said (b), saidparticles having a bulk density of about 0.4 grams per cubic centimeter to about 1.0 gramsper cubic centimeter.in another embodiment, there is provided a method comprising (a) intermixing acomposition comprising substantially dry water-soluble or water-swellable polymer particlescomprised of (i) a first cationic water-soluble or water-swellable polymer; and (ii) at least81015202530CA 02264803 1999-03-04W0 98/ 14405 PCT/U S97/ 16647one second water-soluble polymer different from said first polymer; and (iii) a kosmotropicsalt; and (iv) a chaotropic salt, wherein about 90% or more of said polymer particles eachindividually contains both said (i) and said (ii), said particles having a bulk density of about0.4 grams per cubic centimeter to about 1.0 grams per cubic centimeter, with water to forman aqueous polymer admixture, (b) intermixing said aqueous polymer admixture, in anamount effective for dewatering, with a suspension of dispersed solids, and (c) dewateringsaid suspension of dispersed solids.In another embodiment, there is provided a method comprising (a) intermixing acomposition comprising substantially dry water-soluble or water-swellable polymer particlescomprised of (i) a first cationic water-soluble or water-swellable polymer; and (ii) at leastone second water-soluble polymer different from said first polymer; and (iii) a kosmotropicsalt; and (iv) an anionic organic salt, wherein about 90% or more of said polymer particleseach individually contains both said (i) and said (ii), said particles having a bulk density ofabout 0.4 grams per cubic centimeter to about 1.0 grams per cubic centimeter, with waterto form an aqueous polymer admixture, (b) intermixing said aqueous polymer admixture,in an amount effective for dewatering, with a suspension of dispersed solids, and (c)dewatering said suspension of dispersed solids.in another embodiment, there is provided a method comprising (a) intermixing acomposition comprising substantially dry water-soluble or water-swellable polymer particlescomprised of (i) a first cationic water-soluble or water-swellable polymer having at least onerecurring unit of the formula (I), wherein Ft, is H or CH3, A is O or NH, 8 is an alkylene orbranched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl,or propyl group, R3 is a methyl, ethyl, or propyl group, R, is an alkyl or substituted alkylgroup having from 1 to 10 carbons, or an aryl or substituted aryl group having from 6 to 10carbons, X is a counterion, and R2, R3, and R4 together contain a total of at least 4 carbonatoms; and (ii) at least one second water-soluble polymer different from said first polymer,wherein about 90% or more of said polymer particles each individually contains both said (i)and said (ii), said particles having a bulk density of about 0.4 grams per cubic centimeterto about 1.0 grams per cubic centimeter, with water to form an aqueous polymer admixture,(b) intermixing said aqueous polymer admixture, in an amount effective for dewatering, witha suspension of dispersed solids, and (c) dewatering said suspension of dispersed solids.101520CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647Detailed Description of Preferred EmbodimentsThe aqueous dispersions of the instant invention contain a first cationic water-soluble or water-swellable polymer, preferably a vinyl-addition polymer. The cationic chargeof said first cationic polymer may vary over a broad range by containing from about 1% toabout 100% cationic recurring units, preferably about 5% or greater, more preferably about10% or greater, even more preferably about 20% or greater, most preferably about 30% orgreater, preferably about 90% or less, more preferably about 80% or less, most preferablyabout 70% or less, by mole based on total moles of recurring units in said first cationicpolymer. Cationic recurring units may be formed by post-reaction of polymer, but arepreferably formed by polymerization of cationic monomers. Cationic monomers may includeany cationic monomer, including diallyldialkylammonium halide, cationic (meth)acrylates,and cationic (meth)acrylamides commonly used in preparing water-soluble polymers,preferably diallyldimethylammonium halide, as well as acid and quaternary salts ofdialkylaminoalkyl(alk)acrylate and dialkylaminoa|kyl(alk)acrylamide. Cationic recurring unitsmay be formed by the polymerization of quaternizable monomers such asdialkylaminoalkyl(alk)acrylate or dialkylaminoalkyl(alk)acrylamide, followed by acidificationor quaternization. Most preferably, the first cationic polymer contains cationic recurring unitsof the formula (I), preferably formed by polymerization of the corresponding monomers ofthe formula (II):(|)10101520CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/ 16647(N)wherein Ft, is H or CH3, A is O or NH, B is alkylene or branched alkylene or oxyalkylenehaving from 1 to 5 carbons, R2 and R3 are each individually methyl, ethyl, or propyl, R4 isan alkyl or substituted alkyl group having from 1 to 10 carbon atoms, or an aryl orsubstituted aryl group having from 6 to 10 carbon atoms, X is a counterion, and R2, R3 andR4 together contain at least a total of 4 carbon atoms, preferably at least 5 carbon atoms.in certain preferred embodiments, R4 isa methyl, ethyl or propyl group. in other preferredembodiments, R4 is an alkyl or substituted alkyl group having from 4 to 10 carbon atoms.In other preferred embodiments, R4 is benzyl. Preferably, X is chloride, bromide, iodide,methylsulfate, or ethylsultate.The first cationic water-soluble or water-swellable polymer may be a copolymer andmay contain other cationic recurring units or nonionic recurring units. Nonionic recurringunits may be formed from water-soluble monomers such as N-vinylpyridine, N-vinylpyrrolidone, hydroxya|kyl(meth)acrylates, etc., preferably (meth)acrylamide, or may beformed from hydrophobic monomers having low water-solubility, so long as the inclusion ofthe poorly water-soluble, e.g. hydrophobic, recurring units does not render the resultingpolymer water-insoluble or water—nonswellab|e. The first cationic polymer may containamounts of recurring units of water-soluble non-ionic monomers ranging from 0% to about99%, preferably about 10% or greater, more preferably about 20% or greater, mostpreferably about 30% or greater; preferably about 90% or less, more preferably about 80%or less, most preferably about 70% or less. by mole based on total moles of recurring units111020”2530CA 02264803 1999-03-04W0 98/14405 PCTIUS97/16647in said polymer. The hydrophobic monomers may be hydrocarbon monomers e.g. styrene,butadiene, 1~alkene, vinyl cyclohexane, etc., other vinyl monomers such as vinyl halide,other primarily aliphatic or aromatic compounds with polymerizable double bonds, ormonomers with only moderate water-solubility such as acrylonitrile. Preferably, thehydrophobic monomers are alkyl (alk)acrylates or aryl (alk)acrylates in which the alkyl oraryl groups contain about 1-12 carbon atoms, such as methyl (meth)acrylate, ethyl(meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, ethylhexyl(meth)acrylate, isoalkyl (meth)acrylate, cyclohexyl (meth)acrylate, or aromatic(meth)acrylate, or alkyl or aryl (alk)acrylamides in which the alkyl or aryl groups containabout 1-12 carbon atoms, such as methyl (meth)acrylamide, ethyl (meth)acrylamide, t-butyl(meth)acrylamide, dimethyl (meth)acrylamide, hexyl (meth)acrylamide, ethylhexyl(meth)acrylamide, isoalkyl (meth)acrylamide, cyclohexyl (meth)acrylamide, or aromatic(meth)acrylamide. The first cationic water-soluble or water-swellable polymer may containamounts of hydrophobic non-ionic recurring units ranging from 0% to about 15%, preferablyabout 2% to about 10%, by mole based on total moles of recurring units in said polymer.Although hydrophobic recurring units may be dilutive of the polymer effect in certainapplications, inclusion in controlled amounts may advantageously affect a particularcharacteristic of the aqueous dispersion, e.g. solubility rate, bulk viscosity, cost, ease ofprocessing, performance, etc. Depending on the specific embodiment, it may be preferablefor the polymer to be devoid of hydrophobic recurring units, or to contain chosen amountsof hydrophobic recurring units so as to achieve an advantageous effect withoutdisadvantageously increasing the dilutive effect.The amount of the first cationic water-soluble or water-swellable polymer in theaqueous dispersion is as high as practicable, taking into account the effect of high solidson bulk viscosity, preferably about 5% or greater, more preferably about 10% or greater,most preferably about 20% or greater, by weight based on the total weight of the aqueousdispersion. Generally, the solids are not increased above an amount which increases thebulk viscosity to an impractical level. Practically, the amount of first cationic polymer in theaqueous dispersion is about 75% or less. preferably about 60% or less, more preferablyabout 50% or less, by weight based on total weight. The weight average molecular weightof the first cationic polymer in the aqueous dispersion is not critical and depends on theapplication, but is generally higher than about 1,000,000, preferably greater than about2,000,000, more preferably greater than about 5,000,000, and most preferably greater thanabout 10,000,000.determined by means known to those skilled in the art, preferably by light scattering.Molecular weights of polymers are weight average and may be..1'?1015202530CA 02264803 1999-03-04wo 93/14405 PCT/US97/16647The aqueous dispersions of the instant invention are generally comprised of adiscontinuous phase of small aqueous droplets, containing polymer that is comprisedpredominately of the first cationic water-soluble or water-swellable polymer, that aredispersed in the aqueous continuous phase, although of course minor amounts of said firstpolymer may be found in the continuous phase. Thus, the first cationic water-soluble orwater-swellable polymer generally constitutes more than 50%, preferably more than 75%,of the polymer in a typical small aqueous droplet. The amount of first cationic polymer inthe discontinuous and continuous phases may be determined by known analyticaltechniques e.g. Raman microscopy. Although large aqueous droplets or gel particles maybe formed by adding dry or gel polymer to the other components as in U.S. Patent No.4,673,704 and EP 0 170 394 A2, the aqueous dispersions of the instant invention arepreferred because it is generally more desirable for the first cationic polymer to be in theform of small droplets which are generally held suspended in a continuous matrix of theaqueous phase and do not generally rest substantially in contact with one another.Although aqueous dispersions prepared by polymerization of monomers as herein describedmay sometimes have an average droplet size of about 30 microns or more, the averagedroplet size is generally less than about 30 microns, preferably less than 20 microns, morepreferably about 15 microns or less. Droplet size of a non—spherical droplet is the lengthalong a major axis. Droplet size and shape tend to be a function of reactor conditions suchas stirring rate, reactor configuration, type of stirrer, etc. Preferably, the size of the dropletsis chosen by carrying out the polymerization in the presence of one or more insolublepolymeric seeds, said polymeric seeds being insoluble in an aqueous solution having thesame inorganic salt concentration as said aqueous dispersion.The aqueous dispersions of the instant invention contain a second water-solublepolymer, preferably a vinyl-addition polymer, that is different from and, preferably,incompatible with, said first water-soluble or water-swellable cationic polymer. The secondpolymer is different from the first polymer when it can be distinguished from the first polymeron the basis of a particular physical characteristic e.g. chemical composition, charge,molecular weight, molecular weight distribution, distribution of recurring units along thepolymer chain, etc., by known characterization methods e.g. spectroscopy, chromatography,etc. The second polymer is incompatible with the first polymer when solutions of the twopolymers, at the concentrations present in the aqueous dispersion, do not form ahomogenous mixture when blended, or do not form a homogenous mixture when onepolymer is formed by polymerization of monomers in the presence of the other polymer.13I0202530DJ‘J:CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647The second, preferably cationic, water-soluble polymer in the aqueous dispersionof the instant invention is generally dissolved in the aqueous continuous phase, althoughof course minor amounts may be found in the discontinuous phase. The amount of secondpolymer in the discontinuous and continuous phases may be determined by knownanalytical techniques e.g. Ftaman microscopy. The second polymer may be any nonionicwater-soluble polymer, preferably a polyalkyleneoxlde, a polyvinylalcohol, polyvinylpyridine,polyvinylpyrollidone, polyhydroxylalkyl(alk)acrylate, etc., most preferablypoly(meth)acry|amide. Even more preferably, the second water-soluble polymer is cationic.The second polymer may be any cationic polymer, and the charge may vary over a broadrange by containing about 1% to about 100% cationic recurring units, preferably about 10%or greater, more preferably about 20% or greater, even more preferably about 30% orgreater, by mole based on total moles of recurring units in the polymer. Although in somecases the second cationic polymer may contain about 70% or less, or even about 50% orless, of cationic recurring units, preferably the second polymer is predominately cationic i.e.contains more than 50% cationic recurring units, by mole based on total moles of recurringunits in the polymer; most preferably about 80% or greater of recurring cationic units, samebasis. Cationic recurring units may be formed by polymerization of cationic monomers orby post-reaction of polymer as above, and may be a copolymer and may contain othercationic recurring units or nonionic recurring units as above. Preferred second cationicwater-soluble polymers contain recurring units of diallyldialkylammonium halide, methylchloride quaternary salt of dialkylaminoalkyl(alk)acrylate, dimethyl sulfate quaternary salt ofmethyl chloridedimethylEspecially preferred second cationic water-solubledialkylaminoalky|(alk)acrylate, quaternary salt ofdialkylaminoalkyl(alk)acrylamide. or sulfate quaternary salt ofdialkylaminoaIkyl(alk)acrylamide.polymers contain recurring units of diallyldimethylammonium chloride, methyl chloridequaternary salt of dimethylaminoethyl(meth)acrylate, or dimethyl sulfate quaternary salt ofdimethylaminoethyl(meth)acrylate. One or more second cationic polymers may be used.Depending on the application, it may be preferable for the second polymer to becationic in order to maximize the cationic charge density of the aqueous dispersion. Also,for embodiments which contain salt, it may be preferable for the second polymer to becationic because cationic polymers are often more soluble in salt solution than nonionicpolymers.The amount of the second, preferably cationic, water-soluble polymer in theaqueous dispersion is generally chosen to control aqueous dispersion properties e.g.performance, bulk viscosity, charge, molecular weight, solubility rate, physical stability, e.g.1410._..‘J!202530K1.)’JICA 02264803 1999-03-04W0 98/ 14405 PCT/US97/ 16647settling, etc. Generally, the amount of said second polymer is about 5% or greater,preferably about 10% or greater, more preferably about 20% or greater, most preferablyabout 30% or greater, by weight based on the amount of first cationic water-solublepolymer. Practically, the amount of second water-soluble polymer in the aqueous dispersionis 100% or less, preferably about 80% or less, more preferably about 50% or less, byweight based on the amount of first cationic water-soluble polymer. in certain preferredembodiments, the amounts of the first and second polymers are effective to form anaqueous dispersion. in some embodiments, an aqueous dispersion is not formed in theabsence of the second polymer, and a homogeneous composition is obtained instead.Practically, the amount of first and second polymer may be found by routineexperimentation, and different amounts will ordinarily be used depending on the identity ofthe first and second polymers, the total polymer solids level, the bulk viscosity, cost, easeof production, product performance, etc.The weight average molecular weight of the second water-soluble polymer in theaqueous dispersion is also generally chosen to provide the most advantageous effect, e.g.bulk viscosity, performance, cost, etc., but is generally higher than about 10,000, preferablygreater than about 50,000, more preferably greater than about 500,000, and most preferablygreater than about 1,000,000. Molecular weights of polymers are weight average and maybe determined by means known to those skilled in the art, preferably by light scattering.The second water-soluble polymer is primarily in the continuous phase of the aqueousdispersion, although of course minor amounts may be contained in the dispersed droplets.Preferably, the aqueous dispersions of the instant invention are heterogeneouscompositions in which more than 50%, preferably about 75% or more, of the first cationicwater-soluble or water-swellable polymer is in the form of a discontinuous phase of aqueousdroplets that are dispersed in an aqueous solution that is comprised of more than 50%,preferably about 75% or more, of the second, preferably cationic, water-soluble polymer.The aqueous dispersions of the instant invention may contain a third water-solubleor water—swellable polymer that is different from the first or second polymers. For instance,the third polymer may also be contained in droplets dispersed in the aqueous solution, inwhich case it may be described as discussed above for the first cationic polymer. The thirdpolymer may also be dissolved in the aqueous solution along with the second polymer, inwhich case it may be described as discussed above for the second polymer. Preferably,the third polymer is cationic.A third aqueous dispersion, containing three or more polymers, may be formed byblending first and second aqueous dispersions of the instant invention, wherein the first and1510202530CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647second aqueous dispersions are different from each other. Blending is generally carriedout by intermixing the aqueous dispersions, typically with stirring. Blending may beadvantageous to achieve a balance of properties exhibited by the individual aqueousdispersions, e.g. performance, charge, total polymer solids, cost, molecular weight, etc.Surprisingly, in many cases the blends are stable, e.g. remain in the form of aqueousdispersions having low bulk viscosity e.g. less than 10,000 centipoise for periods of oneweek or more, even when the salt or second polymer level in the blend is greatly differentfrom the level needed to obtain a stable product for one or both of the dispersed polymers,if formulated alone. Also surprisingly, the bulk viscosity of the blend is often lower than thebulk viscosity of any of the individual aqueous dispersions.The molecular weight of the aqueous dispersion, as that term is used herein, issimply the weight average molecular weight of the polymers contained therein, obtained bysubjecting the entire dispersion to a suitable molecular weight characterization techniquee.g. light scattering. Since the aqueous dispersion contains two or more different polymers,each of which may have a molecular weight and molecular weight distribution different fromthe other(s), the molecular weight distribution of the aqueous dispersion may be multimodal.The molecular weight of the aqueous dispersion is generally about 1,000,000 or greater,preferably greater than 2,000,000, more preferably about 3,000,000 or greater, mostpreferably about 5,000,000 or greater.in some cases it may be more convenient to characterize the aqueous dispersionin terms of standard viscosity instead of by molecular weight. As used herein, “standardviscosity" is determined by: diluting an aqueous dispersion with water to form an aqueousadmixture (in the case of water-swellable polymers) or solution (in the case of water-solublepolymers) having a polymer concentration of about 0.2%; mixing together 8.0 g of thisaqueous admixture or solution with 8.6 g of 2M NaCl; and then measuring the viscosity ofthe resultant mixture at 25°C on a rotating cylinder viscometer e.g. Brookfield viscometerequipped with a UL adapter at 60 rpm. The standard viscosities of the aqueous dispersionsof the instant invention are generally about 1.5 centipoise or greater, preferably about 1.8centipoise or greater, more preferably about 2.0 centipoise or greater, most preferably about2.5 centipoise or greater, depending on the application.The aqueous dispersions of the instant invention may also be intermixed withwater-in-oil emulsions or microemuisions of water-soluble polymers to form compositionswhich, though they contain oil, contain proportionately less oil than the water-in-oilemulsions or microemuisions from which they are derived. Consequently, these1610203035W0 98/ 14405CA 02264803 1999-03-04PCT/US97/16647compositions may advantageously produce less secondary pollution, have lowerflammability, etc.Certain embodiments of the instant invention require salt. Effective amounts of salttend to reduce the bulk viscosity of the aqueous dispersion. The salt may be any inorganicsalt, preferably a kosmotropic salt e.g. a chloride, sulfate, phosphate, or hydrogenphosphatesalt, more preferably ammonium sulfate, sodium chloride, and sodium sulfate, mostpreferably sodium sulfate and ammonium sulfate. The counterion may be any counterion,e.g. Group IA and Group llA metal ions, ammonium, etc., preferably ammonium, sodium,potassium and magnesium. Mixtures of salts may be used, and the amount of salt may bechosen to achieve a desirable bulk viscosity or any other desirable effect. Since the saltmay have a dilutlve effect, in certain preferred embodiments the salt is only added inamounts so as to achieve a homogeneous composition in the absence of the second water-soluble polymer. In these embodiments, the aqueous dispersion is not formed by the actionof the salt, but by the interaction of the first and second polymers. Effective or viscosity-reducing amounts of salt may be found through routine experimentation and are generallychosen to reduce the bulk viscosity without causing precipitation of the polymer. In otherpreferred embodiments, the salt is only added in amounts so as to achieve a homogeneouscomposition in the absence of the first cationic polymer. In embodiments where salt ishelpful but not necessary, salt levels may rangeupwards from 0%, preferably about 3% orgreater, most preferably about 5% or greater, by weight based on total weight, dependingon the upper limit to solubility, because solubility of the salt in the aqueous dispersion ispreferred. In embodiments where salt is necessary, salt levels are chosen to favorablyinfluence product attributes such as cost, bulk viscosity, etc. and may range upwards fromabout 1%, preferably about 3% or greater, most preferably about 5% or greater, by weightbased on total weight, depending on the upper limit to solubility, because solubility of thesalt in the aqueous dispersion is preferred. Frequently, no practical effect of the salt isobserved above about 30%, so salt levels are generally about 30% or less, preferably about25% or less, by weight based on total weight. Practically, the salt level may be determinedby routine experimentation, e.g. balancing the tendency for positive product attributes e.g.lower bulk viscosities resulting from higher salt levels, against the negative aspects of saltuse e.g. cost and dilutlve effect.Surprisingly, it has been discovered that mixtures of chaotropic salts withkosmotropic salts, or anionic organic salts with kosmotropic salts, have a tendency toreduce the bulk viscosity of the aqueous dispersion. in many cases, the salt mixture ismore effective than either salt alone, on a weight basis. Useful chaotropic salts include171020253035CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/16647thiocyanates, perchlorates, chlorates, nitrates, bromides, iodides, and mixtures thereof,preferably sodium thiocyanate and sodium iodide. Useful anionic organic salts includeanionic surfactants and anionic hydrotropic salts, preferably aryl and substituted arylsulfonates having from 6 to 22 carbons, preferably 6 to 18 carbons, and alkyl andsubstituted alkyl sulfonates having from 2 to 22 carbons, preferably 4 to 18 carbons, andmixtures thereof. Especially preferred anionic organic salts are dialkylsulfosuccinates,diarylsulfosuccinates, benzenesulfonates, benzenedisulfonates, naphthalensulfonates,naphthalenedisulfonates, and mixtures thereof; 1,3-benzendisulfonates are most preferred.Counterions to the chaotropic and anionic organic salts may be any typical counterion, e.g.Group lA metal ions, ammonium, etc., preferably ammonium, sodium, and potassium.Effective or viscosity-reducing amounts of chaotropic and anionic organic salts may befound through routine experimentation and are generally chosen to reduce the bulk viscositywithout causing precipitation of the polymer. in certain preferred embodiments, the amountsof chaotropic salt, or anionic organic salt, and kosmotropic salt are chosen such that ahomogeneous composition is obtained in the absence of the second cationic polymer; i.e.the concentration of the salts is such that the first cationic polymer is not precipitated in theabsence of the second cationic polymer. Generally, amounts of chaotropic, or anionicorganic, salts are about 10% or less, preferably about 5% or less, and generally 0.5% ormore, preferably 1% or more, by weight based on total weight. At very low chaotropic oranionic organic salt levels, the viscosity-reducing effect of the salt is negligible, whereas thesalt may cause undesirable precipitation or layering at high levels of incorporation. Toachieve a certain bulk viscosity, amounts of kosmotropic salts used with the chaotropic, oranionic organic salt, are generally less than when the kosmotropic salt is used alone, butstill within the ranges given above for the use of inorganic or kosmotropic salts alone.The aqueous dispersions of the instant invention generally have lower bulkviscosities than comparable aqueous dispersions. A comparable aqueous dispersion isgenerally one which is substantially identical in many functional aspects, but lacks aparticular element of the instant invention. In general, the aqueous dispersions of theinstant invention have lower bulk viscosities than comparable aqueous dispersions whichhave substantially the same polymer solids. cationic charge level and weight averagemolecular weight, but which lack an important feature of the instant invention e.g. lack arecurring unit of formula (I); lack the amount of recurring units of formula (I) found in theaqueous dispersions of the instant invention; not made by a process which comprisespolymerizing vinyl-addition monomers comprised of at least one monomer of the formula(ll); not made by a process which comprises polymerizing vinyl-addition monomers1810152030CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647comprised of the amount of monomers of the formula (ll) used in the processes of theinstant invention, etc. For instance, in a composition comprising an aqueous dispersioncomprised of: (a) a discontinuous phase containing polymer that is comprised predominatelyof a first cationic water—soluble or water-swellable polymer having at least one recurring unitof the formula (l), and (b) at least one second water-soluble polymer different from said firstpolymer, a comparable aqueous dispersion may be one which contains the same amountof each component, except the R2, R3 and R4 in the corresponding recurring formula (I) unitof the comparable aqueous dispersion together contain a total of 3 carbon atoms, insteadof the 4 or more carbons in the corresponding recurring unit of formula (I) in the claimedaqueous dispersion.Surprisingly, aqueous dispersions having formula (l) recurring units in which R2, R3and R, contain four or, preferably, five carbons generally have bulk viscosities which aredramatically lower than the bulk viscosities of aqueous dispersions that are substantiallyidentical except that R2, R3 and R4 contain only three carbons. The bulk viscosity ofaqueous dispersions is typically influenced by e.g. total polymer solids, salt level, polymertype, ratio of first cationic polymer to second cationic polymer, etc. as disclosed herein.Although aqueous dispersions having bulk viscosities of about 20,000 centipoise (cps) ormore, or even about 200,000 cps or more may be suitable in certain circumstances, muchlower bulk viscosities are generally preferred for ease of handling. Aqueous dispersionshaving bulk viscosities of about 20,000 centipoise (cps) or less, preferably about 10,000 cpsor less, more preferably about 8,000 cps or less, even more preferably about 5,000 cps orless, most preferably about 2,500 cps or less, may be obtained by the practice of the instantinvention. Bulk viscosity may be measured by any convenient method known to thoseskilled in the art, preferably a rotating cylinder viscometer as described in the Examplesbelow.Aqueous dispersions are preferred which have as many of the followingadvantageous attributes as possible: relatively high cationic polymer solids, preferably 20%or greater, more preferably 25% or greater, by weight based on total; high molecular weight,preferably 2,000,000 or greater, more preferably 5,000,000 or greater; reducedenvironmental impact (low VOC, substantially free of organic solvents and aromatic groups,e.g. aromatic- or benzyl-containing oils or recurring units); minimal levels of diluents(preferably, 20% or less of salt, by weight based on total, and polymer devoid orsubstantially free of hydrophobic recurring units); bulk viscosity about 2,000 cps or less; forrecurring units based on formula (I), R2, R3 and R4 together containing a total of 5 carbons;1910I5202530CA 02264803 1999-03-04W0 98/14405 PCT/US97l16647and superior or equivalent performance. Products having all of these attributes may beobtained by the practice of the present invention.Aqueous dispersions of water-soluble polymers are preferably formed bypolymerization of the corresponding monomers to form the first cationic water-solublepolymer, in the presence of at least one second cationic water-soluble polymer and, incertain embodiments, an inorganic salt. Polymerization may be effected by any initiatingmeans, including redox, thermal or irradiating types. Examples of preferred initiators are2,2’-azobis(2-amidino-propane)dihydrochloride (V-50), 2,2’-azobis(isobutyronitrile), sodiumbromate/sulfur dioxide, potassium persulfate/sodium sulfite, and ammoniumpersulfate/sodium sulfite, as well as peroxy redox initiators e.g. those disclosed in U.S.4,473,689. Initiator levels are chosen in a known manner so as to create polymers of thedesired molecular weight. Amounts of chain transfer agents, e.g. isopropanol, lactic acid,mercaptoethanol, etc. and branching or crosslinking agents, e.g. methylenebisacrylamidemay be added in a known manner to further adjust the properties of the first cationic water-soluble polymer. Depending on the production conditions, e.g. types and relative amountsof chain transfer agent and branching agent, water-swellable or branched, water-solublepolymers may be formed. in general, the use of greater amounts of branching orcrosslinking agent increases the tendency for the product to be water-swellable instead ofwater-soluble, and increased amounts of chain transfer agent tend to reduce molecularweight. When chain transfer agent and branching agent are used together, water-swellableproducts are more likely to be obtained at high branching agent and low chain transferagent levels, whereas branched, water-soluble polymers may be obtained at high chaintransfer and low branching agent levels. Components may be added at any time; e.g. allof the monomers may be present from the onset of the polymerization, or monomers maybe added during the course of the polymerization. If salt is used, all of the salt may bepresent from the onset of the polymerization, or salt may be added during the course of thepolymerization or after polymerization is complete. Likewise, polymerization parameters e.g.temperature and time may be chosen in a known manner, and may be varied during thecourse of the polymerization. Polymerization is generally effected in the presence of aninert gas, e.g. nitrogen. Conventional processing aids e.g. chelating agents, sequestrants,pH adjusters, etc. may be added as required.The aqueous dispersions of the present invention have advantageous aspects inthat they are preferably substantially free of dilutive substances such as surfactant, oil,hydrocarbon liquids, organic solvents, etc. Although viscosity-reducing additives e.g.glycerin, glycerol, alcohol, glycol, etc. may be present in the aqueous dispersions, amounts20101520253035CA 02264803 1999-03-04WO 98/14405 PCT/US97/ 16647should be 2% or less, more preferably 1% or less, most preferably 0.1% or less, in orderto maintain the advantageous properties of the invention.The aqueous dispersions of the instant invention may be homogenous in theabsence of a particular component e.g., said second water-soluble polymer. Homogenouscompositions are generally characterized as being clear or translucent, and are not aqueousdispersions because they do not contain dispersed droplets as described above.Depending on the embodiment, said first cationic water-soluble polymer or said secondcationic water-soluble polymer is dispersion-creating in that aqueous dispersions are notobtained in the absence of an effective or dispersion-creating amount of the particularcomponent.Waters used in the present invention may be from any source, e.g. process water,river water, distilled water, tap water, etc. Preferably, polymerizations are conducted inaqueous solutions that do not contain substantial amounts of materials which detrimentallyaffect the polymerization. Advantageously, the aqueous dispersions of the present inventiontend to dissolve quickly when diluted with water.The aqueous dispersion of the instant invention may be dehydrated to increase thetotal polymer solids content, or to create substantially dry products. Any means known inthe art e.g. stripping, spray drying, solvent precipitation, etc. may be used to reduce thewater content. Surprisingly, partial dehydration may reduce the bulk viscosity of anaqueous dispersion, in spite of the tendency for dehydration to increase polymer solids.Dehydration may be performed by heating, preferably under reduced pressure, although ofcourse excessive heating may be detrimental to polymer properties. A substantially drymass of polymer may be obtained by removal of water, and the mass may be comminutedto create a powdery, particulate, or granular product.Surprisingly, substantially dry polymer products may be obtained by spray-drying theaqueous dispersions of the instant invention. Although oil-containing polymer emulsions anddispersions have been spray-dried, see e.g. U.S. Patent Application Serial No. 08/668,288and references therein, spray-drying of aqueous dispersions, which are generally free of oiland surfactants, has not previously been reported. In accordance with the instant invention,vinyl-addition polymer-containing aqueous dispersions may be sprayed—dn'ed by a suitablemeans into a large chamber through which a hot gas is blown, thereby removing most or allof the volatiles and enabling the recovery of the dried polymer. Surprisingly, the means forspraying the aqueous dispersion into the gas stream are not particularly critical and are notlimited to pressure nozzles having specified orifice sizes; in fact, any known spray-dryingapparatus may be used. For instance, means that are well known in the art such rotary211020Ix)U!30CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/16647atomizers, pressure nozzles, pneumatic nozzles, sonic nozzles, etc. can all be used to spray-dry the aqueous dispersion into the gas stream. The feed rate, feed viscosity, desired particlesize of the spray-dried product, droplet size of the aqueous dispersion, etc. are factors whichare typically considered when selecting the spraying means. The size and shape of thechamber, the number and type of spraying means, and other typical operational parametersmay be selected to accommodate dryer conditions using common knowledge of those skilledin the art.Although closed cycle spray-dryers may be used, open cycle spray-drying systems arepreferred. Gas flow may be cocurrent, countercurrent or mixed flow, cocurrent flow beingpreferred. The hot gas, or inlet gas, may be any gas that does not react or form explosivemixtures with the feed and/or spray-dried polymer. Suitable gases used as the inlet gas aregases known to those skilled in the art, including air, nitrogen, and other gases which will notcause undesirable polymer degradation or contamination, preferably gases containing about20% or less oxygen, more preferably about 15% or less oxygen. Most preferably, inert gasessuch as nitrogen, helium, etc. that contain about 5% or less of oxygen should be used.The dried polymer may be collected by various means such as a simple outlet,classifying cone, bag filter, etc., or the polymer may be subjected to further stages of drying,such as by fluid beds. or agglomeration. The means for collecting the dry polymer product isnot critical. 9There are four interrelated operating parameters in the instant spray-drying process:gas inlet temperature, gas outlet temperature, product volatiles and residence time in the dryer.The outlet temperature generally should be about 150°C or below, preferably about 120°C orbelow, more preferably less than 100°C, even more preferably about 95°C or below, mostpreferably about 90°C or below. The outlet temperature is generally about 70°C or higher,preferably about 75°C or higher. Therefore, outlet temperatures are generally about 70° C toabout 150° C, preferably about 70° C to about 120° C, more preferably about 70° C to less than100°C, even more preferably about 70° C to about 95° C, most preferably about 75°C to about90°C. Outlet temperatures below about 70°C may be suitable in certain instances, thoughgenerally this is less preferred. For instance, at the cost of efficiency, spray drying could becarried out at long residence times, high gas flow rates and low outlet temperatures. Generally,the dryer should be operated at the lowest possible outlet temperature consistent with obtaininga satisfactory product.The inlet temperature, the feed rate, and the composition of the aqueous dispersions mayall affect outlet temperatures. These parameters may be varied to provide a desired outlettemperature. Feed rates are not critical. and generally will vary depending on the size of the22101520-2530CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647dryer and the gas flow rate. inlet gas temperature is less critical than outlet gas temperature,and is generally about 140°C or above, preferably about 160°C or above. The inlet gastemperature is preferably about 200°C or below and more preferably about 180°C or below.Thus, preferred inlet gas temperature ranges from about 140°C to about 200°C, more preferablyfrom about 160°C to about 180°C. Proper inlet gas temperatures tend to avoid productdegradation on the high side and to avoid inadequate drying on the low side.Residence time is a nominal value obtained by dividing the volume of the dryer by thevolumetric gas flow. Residence time is generally at least about 8 seconds, preferably at leastabout 10 seconds. Residence time is generally no more than about 120 seconds, preferablyno more than about 90 seconds, more preferably no more than about 60 seconds, and mostpreferably no more than about 30 seconds. Therefore, the general range of residence time isabout 8 to about 120 seconds, preferably about 10 to about 90 seconds, more preferably about10 to about 60 seconds, and most preferably about 10 to about 30 seconds. it is known tothose skilled in the art that longer residence times are to be expected when larger dryers areused or when the dryer is run in a less efficient manner. For instance, at the cost of efficiency,longer residence times would be expected at very low inlet temperatures and slow gas flowrates. As a practical matter, the residence times useful in the present invention may vary fromthe values described above, depending on the size and type of spray dryer used, the efficiencyat which it is operated, and other operational parameters. Thus, residence times specifiedherein may be modified to accommodate dryer conditions using common knowledge of thoseskilled in the art.When produced according to the spray drying processes disclosed herein, polymerparticles of the instant invention are generally about 10 microns or greater in diameter,preferably about 40 microns or greater, more preferably about 100 microns or greater, mostpreferably about 200 microns or greater. it is preferred that the polymer particles be non-dusting. Dusting and flow problems are typically exacerbated when the polymer particles aresmall, so larger polymer particles are generally desirable. However, very large particles maydissolve more slowly. Therefore, it is generally desirable for the polymer particles to be about1200 microns or less in diameter, preferably about 800 microns or less in diameter, morepreferably about 600 microns or less, most preferably about 400 microns or less. Generally,at least about 90% of the polymer particles range in size from about 10 microns to about 1200microns, preferably at least about 95%, more preferably at least about 98%. The size of thepolymer particles can be varied somewhat by altering the operational parameters e.g. sprayconfiguration, aqueous dispersion viscosity, feed rate, etc. Particles may be substantially231015202530CA 02264803 1999-03-04WO 98114405 PCTIUS97/ 16647spherical or non—spherical; “diameter” of a non-spherical particle is the dimension along a majoraxis.Although in some cases the polymer particles are hollow, porous structures having at leastone opening in their walls, it has been discovered that these features are not always necessaryin order to obtain particles having desirable properties e.g. fast dissolution times. In manycases, the spray-drying parameters e.g. nozzle type, nozzle size, outlet temperature, etc.needed to produce particles that are hollow, porous structures having at least one opening intheir walls are inconvenient or uneconomical, and it is advantageous to produce particles thatlack some or all of these features.The particles formed by the spray-drying processes of the instant invention may bescreened to remove an oversize or underslze fraction. Oversize particles may be fragmentedby e.g. grinding, whereas undersized particles are generally agglomerated. Sizes may bedetermined by methods known to those skilled in the art e.g. sieving, screening, light scattering,microscopy, microscopic automated image analysis, etc.Surprisingly, the bulk densities of the spray-dried polymer particles of the instant inventionare generally greater than the bulk densities of dry polymers prepared by precipitation of e.g.water—in-oil emulsions of the same polymer. Polymer particles having greater density may beadvantageous because they occupy a smaller volume, resulting in e.g. lower shipping andstorage costs. Whereas the densities of precipitated polymers are usually less than about 0.35grams per cubic centimeter (g/cc), the bulk densities of the spray-dried polymer particles of theinstant invention are generally about 0.35 g/cc or greater, preferably about 0.4 g/cc or greater,more preferably about 0.45 g/cc or greater, most preferably about 0.50 g/cc or greater. Thebulk densities of the spray-dried polymer particles of the instant invention are generally about1.1 g/cc or less, preferably about 1.0 g/cc or less, more preferably about 0.95 g/cc or less, mostpreferably about 0.90 g/cc or less. Therefore, the bulk densities of the spray-dried polymerparticles of the instant invention generally range from about 0.35 to about 1.1 g/cc, preferablyabout 0.4 to about 1.0 g/cc, more preferably about 0.45 to about 0.95 g/cc, most preferablyabout 0.50 to about 0.90 g/cc.Under the conditions of drying set forth herein, the polymer particles produced by theprocesses described herein are substantially dry. As used to describe the polymer producedherein, “substantially dry” generally means that the polymer contains about 12% or lessvolatiles. preferably about 10% or less by weight, based on the weight of the spray driedpolymer. The polymer generally contains about 2% or more volatiles, preferably about 5% ormore, by weight based on total weight, and most preferably contains from about 8% to about24101520253035CA 02264803 1999-03-04WO 98/14405 PCT/US97/1664710% volatiles by weight, same basis. The volatiles are measured by determining the weightloss on drying the polymer product at about 105°C for about 30 minutes.it has also been discovered that agglomeration of the polymer particles of the instantinvention may improve the flow properties and dissolution times of the polymers. Agglomeratlonis a known process for increasing particle size and various methods for agglomerating particlesare known to those skilled in the art, e.g. “Successfully Use Agglomeratlon for sizeEnlargement,” by Wolfgang Pietsch, , April 1996, pp. 29-45;“Speeding up Continuous Mixing Agglomeratlon with Fast Agitation and Short ResidenceTimes,” by Peter Koenig, Powder and Bulk Engineering, Febmary 1996, pp. 67-84. Knownagglomeration methods such as natural agglomeration, mechanical agglomeration, tumble orgrowth agglomeration, pressure agglomeration, bindertess agglomeration, agglomeration withbinders, etc. may be used to agglomerate the polymer particles of the instant invention.Agglomeratlon may optionally be followed by drying e.g. fluid bed drying, to remove binder e.g.water. Pressure agglomeration is preferred, and mechanical agglomeration using a waterbinder, followed by fluid bed drying is most preferred.The agglomerates formed by agglomerating the polymer particles of the instant inventiontend to have improved flow properties and faster dissolution times when compared to theunagglomerated polymer particles. Preferably, the agglomerates are non-dusting. Typically,about 90% of the agglomerates of the instant invention have an agglomerate size of about 120microns or greater, preferably about 160 microns or greater, more preferably about 200 micronsor greater, most preferably about 300_microns or greater. Generally, about 90% of theagglomerates have an agglomerate size of about 1500 microns or less, preferably about 1200microns or less, more preferably about 1100 microns or less, most preferably about 1000microns or less. Thus, about 90%, preferably 95%, of the agglomerates have a size in therange of about 120 to about 1500 microns, preferably about 160 microns to about 1200microns, more preferably about 200 microns to about 1100 microns, most preferably about 300microns to about 1000 microns Usually, at least about 5% of the agglomerates, preferably atleast about 10%, most preferably at least about 15%, are larger than about 900 microns. Theagglomerates fonned by agglomerating the spray-dried particles of the instant invention maybe screened to remove an oversize or undersize fraction. Preferably, agglomerates larger thanabout 1200 microns and smaller than about 175 microns are removed by e.g. screening.Oversize agglomerates are generally fragmented by e.g. grinding, whereas undersizedagglomerates are generally recycled into the agglomerator.The bulk density values of the agglomerates of the instant invention tend to be lower thanthe bulk density values of the spray-dried particles from which they are formed. The bulk251015202530CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647densities of the agglomerates of the instant invention are generally about 0.35 g/cc or greater,preferably about 0.4 g/cc or greater, mo: e preferably about 0.45 g/cc or greater, most preferablyabout 0.50 g/cc or greater. The bulk densities of the agglomerates of the instant invention aregenerally about 1.0 g/cc or less, preferably about 0.95 g/cc or less, more preferably about 0.90g/cc or less, most preferably about 0.85 g/cc or less. Therefore, the bulk densities of theagglomerates of the instant invention generally range from about 0.35 to about 1.0 g/cc,preferably about 0.4 to about 0.95 g/cc, more preferably about 0.45 to about 0.90 g/cc, mostpreferably about 0.50 to about 0.85 g/cc.in order to obtain agglomerates of a preferred size, it is preferred that the polymer particlesthemselves be of such a size that they are agglomerable. Agglomeration obviously tends tomultiply the average particle size, so that it is frequently easier to cause large increases inparticle size than it is to cause small increases .in particle size. Therefore, to produceagglomerates of a preferred size or size range, it is generally preferred to agglomerate particlesthat are much smaller than the desired agglomerate size, rather than particles that are onlyslightly smaller. Agglomerable particles are generally those that may be convenientlyagglomerated to produce agglomerates having a preferred size. It is possible, but lesspreferred, to agglomerate larger particles to produce agglomerates that are larger than desired,then remove the oversize agglomerates as described above.The substantially dry polymer particles and agglomerates of the present invention aregenerally comprised of the polymer that was contained in the aqueous dispersion that wasspray—dried, as discussed hereinabove.Spray-drying of the aqueous dispersions of the instant invention is advantageous becausetypically 90% or greater, preferably 95% or greater, most preferably substantially all, of theresultant spray-dried polymer particles each individually contains two or more water-soluble orwater-swellable vinyl-addition polymers, so that stratification effects may be minimized.Stratification may occur when two different dry polymers having differing particle sizes or particlesize distributions are blended together because of the tendency for the larger particles to settletowards the bottom of the container. Stratification on storage may affect blend productperformance as the top of the container tends to become enriched in the polymer having thesmaller particle size. For obvious reasons, changes in product performance as a function ofstorage depth are to be avoided, and it is generally preferred that each polymer in a blend beof similar particle size, see e.g. EP 479 616 A1 and U.S. Patent No. 5,213,693. A dry blendof the two different polymers is likely to exhibit greater stratification than a dry blend obtainedby spray-drying the instant aqueous dispersions because the majority of the spray-dried polymerparticles of the instant invention each individually contains two or more water-soluble or water-2610152030CA 02264803 1999-03-04W0 93/14405 PCT/US97/16647swellable vinyl-addition polymers. Surprisingly, the spray-dried aqueous dispersions of theinstant invention tend to dissolve faster than polymers obtained by spray-drying conventionalwater-in—oil emulsions of similar polymers.A suspension of dispersed solids may be dewatered by a method which comprises(a) intermixing an effective amount of an aqueous dispersion of polymers, or aqueousadmixture thereof, with a suspension of dispersed solids, and (b) dewatering saidsuspension of dispersed solids. Substantially dry polymers derived from the aqueousdispersions of the instant invention as described above may also be used to dewatersuspended solids. For instance, a suspension of dispersed solids may be dewatered bya method which comprises (a) intermixing an effective amount of a substantially dry water-soluble or water-swellable polymer, or aqueous admixture thereof, with a suspension ofdispersed solids, and (b) dewatering said suspension of dispersed solids. Preferably, anaqueous admixture of the dry polymer or aqueous dispersion is prepared by intermixing thedry polymer or aqueous dispersion with water, more preferably by dissolving the drypolymer or aqueous dispersion in water to form a dilute polymer solution. Effective amountsof dry polymer or aqueous dispersion are determined by methods known in the art,preferably by routine laboratory or process experimentation.Examples of suspensions of dispersed solids which may be dewatered by meansof the instant invention are municipal and industrial waste dewatering, clarification andsettling of primary and secondary industrial and municipal waste, potable water clarification,etc. Because of the advantageous aspects of the invention e.g. substantially oil—free.minimum amounts of inactive diluents, little or no surfactant, etc., the polymers may beespecially wel|—suited to situations where part or all of the dewatered solids or clarified wateris returned to the environment, such as sludge composting, land application of sludge,pelletization for fertilizer application, release or recycling of clarified water, papermaking, etc.Other applications which may benefit from the advantageous aspects of the instantinventions include soil amendment, reforestation, erosion control, seed protection/grovvth,etc., where the aqueous dispersion or dry polymer, preferably an aqueous admixturethereof, is advantageously applied to soil.Other examples of suspensions of dispersed solids which may be dewatered bymeans of the instant invention are found in the papermaking area, e.g. the aqueousdispersions or dry polymer may be used as retention aids, drainage aids, formation aids,washer/thickener/drainage production aid (DNT deink application), charge control agents,thickeners, or for clarification, deinking, deinking process water clarification, settling, colorremoval. or sludge dewatering. The polymers of the instant invention may also be used in271020253035CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/ 16647oil field applications such as petroleum refining, waster clarification, waste dewatering andoil removal.Dewatering and clarification applications for the aqueous dispersions and drypolymers of the instant invention may also be found in the food processing area, includingwaste dewatering, preferably waste dewatering of poultry beef, pork and potato, as well assugar decoloring, sugar processing clarification, and sugar beet clarification.Mining and mineral applications for the aqueous dispersions and dry polymers ofthe instant invention include coal refuse dewatering and thickening, tailings thickening, andBayer process applications such as red mud settling, red mud washing, Bayer processfiltration, hydrate flocculation, and precipitation.Biotechnological applications for the aqueous dispersions and dry polymers of theinstant invention include dewatering and clarification of wastes and preferably, dewateringand clarification of fermentation broths.The aqueous dispersions of the instant invention may be employed in the aboveapplications alone, in conjunction with, or serially with, other known treatments.All patents, patent applications, and publications mentioned above are herebyincorporated herein by reference. Unless otherwise specified, all percentages mentionedherein are understood to be on a weight basis.The Standard Viscosity (SV) values in the following Examples were determined bymixing together 8.0 g of a 0.2 wt. % polymer solution in water and 8.6 g of 2M NaCl, thenmeasuring the viscosity of the resultant solution at 25°C on a Brookfield viscometerequipped with a UL adapter at 60 rpm. Molecular weights were determined by highperformance size exclusion chromatography using a light scattering detector.The bulk density of polymer particles and agglomerates was determined by adding theparticles or agglomerates to a suitable preweighed measuring container and “tapping” or slightlyagitating the container to cause the particles or agglomerates to settle. The volume of thepolymer was then read from the measuring container, the measuring container weighed, andthe bulk density calculated in units of grams per cubic centimeter (g/cc).EXAMPLE 1A suitable vessel equipped with a mechanical stirrer, reflux condenser, and anitrogen inlet tube was charged with 17.10 parts deionized water and 9 parts of a 40%aqueous solution of the polymer obtained by polymerizing the methyl chloride quaternarysalt of dimethylaminoethylmethacrylate (poly(DMAEM.MeCl)), weight average molecular281015202530CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647weight about 200,000. After completion of dissolution, 7.08 parts of a 53.64% aqueoussolution of acrylamide (AMD), and 14.56 parts of a 72.80% solution of the dimethyl sulfatesalt of diethylaminoethylacrylate (DEAEA.DMS) were added and mixed. To this mixture,8.1 parts ammonium sulfate, 0.7 parts citric acid, and 2.02 parts of a 1% solution of chelantethylenediaminetetraacetic acid tetrasodium salt (EDTA) were added and mixed. The pHof the mixture was about 3.3. The vessel was sealed and sparged with nitrogen for 30minutes, and then polymerization was started by adding 1.44 parts of 1% aqueous solutionof 2,2‘-azobis(2-amidino-propane)dihydrochloride (V-50). The reaction mixture was heatedto 40° C for 2 hours and then raised to 50°C and held for an additional 8 hours. Theconversion was greater than 99%. A stable fluid aqueous dispersion was obtained. Thebulk viscosity (BV) of the dispersion was 2250 centipoise (cps) showing preferable fluidityas measured with a Brookfield viscometer, No. 4 spindle, 30 rpm at 25° C. The dispersionwas dissolved to give a standard viscosity (SV) of 2.56 cps.EXAMPLES 2-8Additional aqueous dispersions were prepared in the same manner as Example 1,showing the effect of various polymer and ammonium sulfate salt levels on bulk viscosityas shown in Table 1.Table 1FIRSTPOLYMER°/o SOLIDSSECONDPOLYMER %°/o SOLIDS SALT% TOTALSOLIDSExample No.30 24 13.530 24 12.530 24 1330 2430 2429101520l\)U:30CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/166476 13.5 2,640 2.6114 3,470 2.397,080 2.17 EXAMPLE 9A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and a nitrogen inlet was charged with 72.60 parts of deionized water and 30.8parts of a 40% aqueous solution of poly(DMAEM.MeCi), weight average molecular weightabout 222,600. After dissolution was complete, 24.37 parts of a 53.33% aqueous solutionof acrylamide and 45.93 parts of a 79% aqueous solution of DEAEA.DMS were added andmixed. To this mixture, 31.9 parts ammonium sulfate, 2.57 parts citric acid, and 6.9 partsof 1% solution of EDTA were added and mixed. The pH of the mixture was about 3.3. Thevessel was sealed and sparged with nitrogen for 30 minutes, and then polymerization wasstarted by adding 4.93 parts of 1% solution of V—50. The reaction mixture was heated to40°C for 2 hours and then raised to and held at 50°C for 4 hours. The overall conversionwas greater than 99%. A stable fluid aqueous dispersion was obtained. The bulk viscosityof this dispersion was about 1460 cps showing preferable fluidity as measured with aBrookfield viscometer, No. 4 spindle, 30 rpm at 25° C. The dispersion was dissolved to givea SV of 2.40 cps.EXAMPLES 10-33Additional aqueous dispersions were prepared in the same manner as Example 9demonstrating the effect of total polymer solids, ratio of first cationic to second cationicpolymer, second cationic polymer molecular weight, and ammonium sulfate salt level on thebulk viscosity (BV) of the aqueous dispersion, as shown in Table 2.3010152025303540WO 98/14405EXAMPLENO.WBTOTALSOUDS282828282828282830303030302828282727CA 02264803 1999-03-04HRSTPOLYMER%SOUDS22.422.422.422.422.422.422.422.42424242424Table 2SECONDPOLYMER%SOUDS5.65.65.65.65.65.65.631SECONDPOLYMERMW222,600194,000199,300172,870221,500159,000145.000199,300242,900230,600230,600230,600230,600230,600230,600230,600230,600230,600PCT/U S97/ 16647101520253035CA 02264803 1999-03-04W0 93/14405 PCT/US97/1664727 230,600 . 1 ,770 2.4328 . . 230,600 . 1,820 2.5629 . . 230,600 3,120 2.4430 230,600 1,620 2.531 230.600 . 96232 230,600 1 ,50033 . . 230,600 . 1 ,260EXAMPLE 34This polymerization was carried out in the same manner as Example 9, except thata poly(DMAEM.MeCI) having a weight average molecular weight of about 395,000 wasused. A stable fluid aqueous dispersion was obtained. The bulk viscosity of this aqueousdispersion was about 5100 cps showing preferable fluidity as measured with a BrookfieldViscometer, No. 4 spindle, 30 rpm at 25° C. The dispersion was dissolved to give a SV of2.35 cps.EXAMPLE 35This polymerization was carried out in the same manner as Example 34, exceptthat 2.46 parts of 10% glycerol solution was added. Polymerization proceeded smoothly.A stable fluid aqueous dispersion was obtained. The bulk viscosity of this dispersion wasabout 3700 cps as measured with a Brookfield Viscometer, No. 4 spindle, 30 rpm at 25°Cshowing improved fluidity. The bulk viscosity was greatly reduced relative to Example 34,demonstrating the viscosity-reducing effect of the glycerol additive. The dispersion wasdissolved to give a SV of 2.35 cps.3210152030CA 02264803 1999-03-04“'0 93/14405 PCT/US97/16647EXAMPLE 36A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and nitrogen inlet tube was charged with 39.73 parts deionized water and30.1 parts of 41% poiy(DMAEM.MeCl), weight average molecular weight about 395,000.After completion of dissolution, 23.77 parts of a 53.57% aqueous solution of acrylamide.45.20 parts of an 80% aqueous solution of DEAEA.DMS and 38.7 parts of 1% aqueoussolution of tertiary butyl acrylamide were added and mixed. To this mixture, 49.28 partsammonium sulfate, 2.57 parts citric acid, and 3.45 parts of 2% EDTA were added andmixed. The pH of the mixture was about 3.3. The vessel was sealed and sparged withnitrogen for 30 minutes, and then polymerization was started by adding 246 parts of 2%V-50. The reaction mixture was raised to 40°C for 2 hours and then raised to 50°C for anadditional 4 hours. The overall conversion was greater than 99%. A stable iluid aqueousdispersion was obtained. The bulk viscosity of this aqueous dispersion was about 1900 cpsas measured with a Brooktield viscometer No. 4 spindle, 30 rpm at 25° C, showingimproved fluidity compared to Example 34 and demonstrating the effect of incorporatinghydrophobic recurring units of tertiary butyl acrylamide. The aqueous dispersion wasdissolved to give a SV of 2.32 cps.EXAMPLE 37A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and nitrogen inlet tube was charged with 78.84 parts deionized water and30.1 parts of 41% poiy(DMAEM.MeCl), weight average molecular weight about 395,000.After completion of dissolution, 20.95 parts of a 53.57% aqueous solution of acrylamide,42.73 parts of a 80% aqueous solution of DEAEA.DMS and 4.84 parts of a 80% aqueoussolution of the benzyl chloride quaternary salt of dimethylaminoethyl acrylate (DMAEA.BzCl)were added and mixed. To this mixture, 49.28 pans ammonium sulfate, 2.57 parts citricacid, and 3.45 parts of 2% EDTA were added and mixed. The pH of the mixture was about3.3. The vessel was sealed and sparged with nitrogen for 30 minutes, and thenpolymerization was started by adding 2.46 parts of 2% V-50. The reaction mixture wasraised to 40°C for 2 hours, and then raised to and held at 50° C for 4 hours. The overallconversion was greater than 99%. A stable fluid aqueous dispersion was obtained. Thebulk viscosity of this dispersion was about 3840 cps as measured with a Brookfield331015loU:3035CA 02264803 1999-03-04W0 98’ 1‘“°5 PCT/US97/16647Viscometer No. 4 spindle, 30 rpm at 25°C showing preferable fludlty. The dispersion wasdissolved to give a SV of 2.14 cps.EXAMPLE 38A suitable vessel with an external jacket for heating or cooling was equipped witha mechanical stirrer, reflux condenser, thermocouple and nitrogen inlet tube. The vesselwas charged with 294.47 parts deionized water and 117.60 parts of 40% aqueous solutionof poly(DMAEM.MeCl), weight average molecular weight about 210,000. After completionof dissolution, 94.03 parts of a 52.77% aqueous solution of acrylamide and 173.18 parts ofan 80% aqueous solution of DEAEA.DMS were added and mixed. To this mixture, 130.20parts ammonium sulfate, 9.83 parts citric acid, and 13.17 parts of 2% EDTA were addedand mixed. The pH of the mixture was about 3.3. The vessel was sealed and sparged withnitrogen for 30 minutes, and then polymerization was started by adding 7.53 parts of %V-50. The reaction mixture was heated to 40°C for 2 hours and then raised to and held at50°C for 4 hours. The overall conversion was greater than 9 %. A stable fluid aqueousdispersion was obtained. The bulk viscosity of this dispersion was about 760 cps asmeasured with a Brookfield viscometer No. 4 spindle, 30 rpm at 25°C showing preferablefluidity. The dispersion was dissolved to give a SV of 2.52 cps.EXAMPLE 39A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and nitrogen inlet tube was charged with 6318 parts deionized water and30.8 parts of 40% aqueous solution of poly(DMAEM.MeCl), weight average molecularweight about 230,600. After completion of dissolution, 27.96 parts of a 53.33% aqueoussolution of acrylamide (AMD), 26.02 parts of a 80% aqueous solution of DEAEA.DMS and16.94 parts of a 80% aqueous solution of the methyl chloride quaternary salt ofdimethylaminoethylacrylate (DMAEA.MeCl) were added and mixed. To this mixture, 40.7parts ammonium sulfate, 2.57 parts citric acid, and 6.9 parts of 1% EDTA were added andmixed. The pH of the mixture was about 3.3. The vessel was sealed and sparged withnitrogen for 30 minutes, and then polymerization was started by adding 4.93 parts of 1%V-50. The reaction mixture was raised to 40° C for 2 hours, and then raised to and heldat 50° C for 4 hours. The overall conversion was greater than 99%. A stable fluid aqueousdispersion was obtained. The bulk viscosity of this dispersion was about 3840 cps as341520I\)U:3035CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647measured with a Brookfield Viscometer, No. 4 spindle, 30 rpm at 25° C showing goodfluidity. The dispersion was dissolved to give a SV of 2.14 cps.EXAMPLES 40-42Polymerizations were carried out in the same manner as Example 39 except thatthe bulk viscosity was adjusted by varying the level of ammonium sulfate salt as shown inTable 3. These Examples demonstrate that aqueous dispersions having low bulk viscositiesand high polymer solids may be prepared, wherein the first cationic polymer is aDMAEA.MeCl / DEAEA.DMS / AMD terpolymer.Table 3‘FIRST SECONDEXAMPLE % TOTAL POLYMER POLYMER %NO. SOLIDS % SOLIDS % SOLIDS SALT BV (cps) SV (cps)39 28 22.4 5.6 18.5 2,620 2.9940 28 22.4 5.6 18 4.310 2.9641 28 22.4 5.6 19 1,820 2.6542 28 22.4 5.6 19.5 2,000 2.62EXAMPLE 43A suitable vessel equipped with an external jacket for heating or cooling, amechanical stirrer, reflux condenser, thermocouple and nitrogen inlet tube was charged with260.35 parts deionized water and 117.6 parts of a 40% aqueous solution ofpoly(DMAEM.MeCl), weight average molecular weight about 210,000. After completion ofdissolution, 107.89 parts of a 52.77% aqueous solution of acrylamide, 99.35 parts of a 80%aqueous solution of DEAEA.DMS and 64.68 parts of a 80% aqueous solution ofDMAEA.MeCl were added and mixed. To this mixture, 271.92 parts ammonium sulfate, 9.8335102530CA 02264803 1999-03-04W0 98/14405PCT/US97/16647parts citric acid, and 13.17 parts of 2% EDTA were added and mixed. The pH of the mixturewas about 3.3. The vessel was sealed and sparged with nitrogen for 30 minutes, and thenpolymerization was started by adding 7.58 parts of 2.5% V-50. The reaction mixture wasraised to 40°C for 2 hours, and then raised to and held at 50° C for 4 hours. The overallconversion was greater than 99%. A stable fluid aqueous dispersion was obtained. Thebulk viscosity of this dispersion was about 1240 cps as measured with a Brookfieldviscometer, No. 4 spindle, 30 rpm at 25° C showing good fluidity. The dispersion wasdissolved to give a SV of 2.74 cps.EXAMPLE 44A suitable vessel equipped with a mechanical stirrer, reflux condenser. and nitrogeninlet tube was charged with 1886 parts deionized water and 9 parts of a 40% aqueoussolution of poly(DMAEM.MeCl), weight average molecular weight about 200,000. Aftercompletion of dissolution, 4.39 parts of a 53.64% aqueous solution of acrylamide and 15.19parts of a 79.3% aqueous solution of DEAEA.DMS were added and mixed. To this mixture,8.4 parts ammonium sulfate, 0.7 parts citric acid, and 2.02 parts of 1% EDTA were addedand mixed. The pH of the mixture was about 3.3. The vessel was sealed and sparged withnitrogen for 30 minutes, and then polymerization was started by adding 1.44 pans of 1%V-50. The reaction mixture was raised to 40°C for 2 hours and then raised to and held at50° C for 8 hours. The conversion was greater than 99%. A stable fluid aqueous dispersionwas obtained. The bulk viscosity of this dispersion was about 850 cps as measured witha Brookfield viscometer, No. 4 spindle, 30 rpm at 25° C showing preferable fluidity. Thedispersion was dissolved to give a SV of 2.27 cps.EXAMPLES 45-49Additional aqueous dispersions were prepared in the same manner as Example 44,demonstrating the effect of ratio of first cationic to second cationic polymer and salt contenton the bulk viscosity of the dispersion as shown in Table 4.361015203035CA 02264803 1999-03-04W0 98/14405 PCTIUS97/16647Table 4FIRSTPOLYMER% SOLIDSSECONDPOLYMER %% SOLIDS SALT BV (cps) SV (cps)EXAMPLE % TOTALNO. SOLIDS44 30 24 14 852 2.2745 30 24 12 2,400 2.1946 30 24 13 1 ,10047 30 24 15 1 .77048 30 25 13 1 ,26O49 30 25 14 4,75050 30 24 6* 14 780*Molecular weight of second polymer was about 222,600.EXAMPLE 51A suitable vessel equipped with a mechanical stirrer, reflux condenser, and nitrogeninlet tube was charged with 92.9 parts deionized water and 30.1 parts of a 41% aqueoussolution of poly(DMAEM.MeCl), weight average molecular weight about 395,000. Aftercompletion of dissolution, 15.03 parts of a 53.57% aqueous solution of acrylamide and51.53 parts of an 80% aqueous solution of DEAEA.DMS were added and mixed. To thismixture 22 parts of sodium sulfate, 2.57 parts citric acid, and 3.45 parts of 2% EDTA wereadded and mixed. The pH of the mixture was about 3.8. The vessel was sealed andsparged with nitrogen for 30 minutes, and then polymerization was started by adding 2.46parts of 2% V-50. The reaction mixture was raised to 40°C for 2 hours and then raised toand held at 50° C for 4 hours. The overall conversion was greater than 99%. A stable fluidaqueous dispersion was obtained. The bulk viscosity of this dispersion was about 1100 cpsas measured with a Brooktield Viscometer, No. 4 spindle, 30 rpm at 25°C. The dispersion37101520'25CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/16647was dissolved to give a SV of 2.19 cps. This Example demonstrates the effectiveness ofsodium sulfate.EXAM P LE 52A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and nitrogen inlet tube was charged with 17.57 parts deionized water and 9parts of a 40% aqueous solution of poly(DMAEM.MeCl), weight average molecular weightabout 200,000. After completion of dissolution, 4.77 parts of a 53.64% aqueous solutionof acrylamide, 12 parts of a 79.3% aqueous solution of DEAEA.DMS and 2.91 parts of an80% aqueous solution of DMAEA.MeC| were added and mixed. To this mixture, 9.6 partsammonium sulfate, 0.7 parts citric acid, and 2.02 parts of 1% EDTA were added and mixed.The pH of the mixture was about 3.3. The vessel was sealed and sparged with nitrogen for30 minutes, and then polymerization was started by adding 1.44 parts of 1% V-50. Thereaction mixture was raised to 40°C for 2 hours and then raised to and held at 50° C for 4hours. The overall conversion was greater than 99%. A stable fluid aqueous dispersion wasobtained. The bulk viscosity of this dispersion was about 800 cps as measured with aBrookfield viscometer, No. 4 spindle, 30 rpm at 25° C showing good fluidity. The dispersionwas dissolved to give a SV of 2.3 cps.EXAM PLES 53-80Polymerizations were carried out in the same manner as Example 52. The effectof total polymer solids, first cationic polymer composition (in terms of % AMD, °/0DEAEA.DMS and % DMAEA.MeCl in monomer feed), ratio of first cationic to secondcationic polymer, and ammonium sulfate salt content on the bulk viscosity of the aqueousdispersion is demonstrated as shown in Table 5.3810203040W0 98/ 14405CA02264803 1999-03-04PCT/US97ll6647'TatHe 5FIRST ONDOTAL POLYMER LYMERLIDS SOLIDS SOLIDS30 2430 2430 2430 2430 2430 2430 2430 2430 2530 2530 2530 2430 2430 2430 2430 2430 2423.3910203035CA 02264803 1999-03-04“'0 98’1""°5 PCT/US97/1664723.44 5.86 . 2,900 2.423.44 5.86 6,600 2.2422.8 5.7 200,000+ 2.3522.8 5.7 200,000+ 2.3422.4 5.6 200,000+ 2.523.2 5.8 18200,000+ 2.223.2 5.8 18.5 5,54023.2 5.8 19 3,57023.2 5.8 18 6,35023.2 5.8 18.5 3,06023.2 5.8 19 200,000+EXAMPLE 81A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and nitrogen inlet tube was charged with 89 parts deionized water and 20.9parts of a 40% aqueous solution of po|y(DMAEM.MeCl), weight average molecular weightabout 190,000. After completion of dissolution, 30.96 parts of a 52.77% aqueous solutionof acrylamide and 21.38 parts of a 80% aqueous solution of DEAEA.DMS were added andmixed. To this mixture, 49.5 parts ammonium sulfate, 2.57 parts citric acid, and 2.34 partsof 1% EDTA were added and mixed. The pH of the mixture was about 3.3. The vessel wassealed and sparged with nitrogen for 30 minutes, and then polymerization was started byadding 3.34 parts of 1% V-50. The reaction mixture was raised to 40°C for 2 hours andthen raised to and held at 50° C for 4 hours. The combined conversion was greater than99%. A stable fluid aqueous dispersion was obtained. The bulk viscosity of this dispersion40101520toUI3035W0 98/ 14405C showing good fluidity. The dispersion was dissolved to give a SV of 1.60 cps.Polymerizations were carried out in the same manner as Example 81. The effectof chelant (EDTA) concentration, chain transfer agent (lactic acid), first cationic polymercomposition (in terms of % AMD, % DEAEA.DMS, and % DMAEA.MeCl in monomer feed).ratio of first cationic to second cationic polymer, and ammonium sulfate salt content onCA 02264803 1999-03-04PCT/US97/16647was about 280 cps as measured with a Brookfield viscometer, No. 4 spindle, 30 rpm at 25°EXAMPLES 82-97standard viscosity and bulk viscosity are demonstrated as shown in Table 6.% ‘TrNO. AMD DE.AEA.DMS‘%DM/\EA.McCl'1}TOTALSOLIDSTable 6FIRST SECOND ‘TrPOLYMER POLYMER L-’\C'TlC‘% SOLIDS ‘Xv SOLXDS ACID142,000411030CA 02264803 1999-03-04W0 98/14405PCT/US97/16647 ‘Molecular weight of second polymer was about 222,600.EXAMPLE 98A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and nitrogen inlet tube was charged with 87.97 parts deionized waternand20.9 parts of a 40% aqueous solution of poly(DMAEM.MeCl), weight average molecularweight about 190,000. After completion of dissolution, 33.99 parts of a 52.77% aqueoussolution of acrylamide, 11.74 parts of a 80% aqueous solution of DEAEADMS and 7.64parts of a 80% aqueous solution of DMAEA.MeCl were added and mixed. To this mixture.49.5 parts ammonium sulfate, 2.57 parts citric acid, and 234g of 2% EDTA were added andmixed. The pH of the mixture was about 3.3. The vessel was sealed and sparged withnitrogen for 30 minutes, and then polymerization was started by adding 2.34 parts of 1%V-50. The reaction mixture was raised to 40°C for 2 hours and then raised to and held at50°C for 4 hours. The overall conversion was greater than 99%. A stable fluid aqueousdispersion was obtained. The bulk viscosity of this dispersion was about 760 cps asmeasured with a Brookfield Viscometer, No. 4 spindle, 30 rpm at 25°C. The dispersion wasdissolved to give a SV of 2.09 cps.101520rdUI3035CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647EXAMPLES 99-1 00Polymerizations were carried out in the same manner as Example 97. The effectof chain transfer agent (lactic acid) concentration on bulk viscosity is demonstrated asshown in Table 7.Table 7FIRST SECOND LACTICEXAMPLE % TOTAL POLYMER POLYMER ACID %NO. soups % soups % souos % SALT BV sv (cps)98 19 15.2 3.3 0 22.5 760 2.0999 19 152 38 025 225 460 286100 19 152 38 05 225 340 274EXAMPLE 101A suitable vessel equipped with a mechanical stirrer, reflux condenser,thermocouple and nitrogen inlet tube was charged with 82.15 parts deionized water and30.8 parts of a 20% aqueous solution of poly(dlallyldimethylammonium chloride)(poly(DADMAC)), weight average molecular weight about 289,000. After completion ofdissolution, 48.24 parts of a 52.77% aqueous solution of acrylamide and 13.27 parts of an80% aqueous solution of DEAEADMS were added and mixed. To this mixture, 49.5 partsammonium sulfate, 2.57 parts citric acid, 1.67 parts of 10% lactic acid, and 3.34 parts of 2%EDTA were added and mixed. The pH of the mixture was about 3.3. The vessel was sealedand sparged with nitrogen for 30 minutes, and then polymerization was started by adding3.34 parts of 1% V-50. The reaction mixture was raised to 40°C for 2 hours and then raisedto and held at 50°C for 4 hours. The combined conversion was greater than 99%. A stablefluid aqueous dispersion was obtained. The bulk viscosity of this dispersion was about 960cps as measured with a Brookfield Viscometer, No. 4 spindle, 30 rpm at 25°C showingpreferable fluidity. The dispersion was dissolved to give a SV of 3.67 cps. This Exampledemonstrates aqueous dispersions having poly(DADMAC) as the second cationic polymer.43101520253035CA 02264803 1999-03-04WO 98/14405PCT/US97/16647EXAM PLE 1 02A suitable vessel equipped with an external jacket for heating or cooling,mechanical stirrer, reflux condenser, thermocouple and nitrogen inlet tube was charged with262.6 parts deionized water, 47.4 parts of a 40% aqueous solution of poly(DMAEM.MeCl),weight average molecular weight about 41,500, and 92.60 parts of a 40% aqueous solutionof poly(DMAEM.MeCl), weight average molecular weight about 205,000. After completionof dissolution, 88.1 parts of a 53.12% aqueous solution of acrylamide and 133.9 parts ofa 72.6% aqueous solution of the methyl chloride quaternary salt of diethylaminoethylacrylate(DEAEA.MeC|) were added and mixed. To this mixture, 144 parts ammonium sulfate, 2.644parts citric acid, and 14.4 parts of 1% EDTA were added and mixed. The pH of the mixturewas about 3.3. The vessel was sealed and sparged with nitrogen for 30 minutes, and thenpolymerization was started by adding 14.4 parts of 2% V—50. The reaction mixture wasraised to and held at 40-45° C for 6 hours. The conversion was greater than 99.9%. Astable fluid aqueous dispersion was obtained. The bulk viscosity of this dispersion wasabout 2,200 cps as measured with a Brookfield viscometer, No. 4 spindle, 30 rpm at 25°C.The dispersion was dissolved to give a SV of 3.31 cps. This Example demonstrates anaqueous dispersion having a third cationic polymer.EXAMPLE 103Polymerization was carried out in the same manner as Example 102, except thatthe two poly(DMAEM.MeCl) polymers were replaced with a single poly(DMAEM.MeCl)having a weight average molecular weight of about 1,500,000. The bulk viscosity of thisdispersion was about 8.000 cps as measured with a Brookfield viscometer, No. 4 spindle,30 rpm at 25°C showing preferable fluidity. The dispersion was dissolved to give a SV of2.45 cps.EXAMPLE 104A suitable vessel equipped with an external jacket for heating, mechanical stirrer,reflux condenser, thermocouple and nitrogen inlet tube was charged with 23.8 partsdeionized water and 25.3 parts of a 20% aqueous solution of poly(DADMAC), weightaverage molecular weight about 289,000. After completion of dissolution, 7.9 parts of a53.1% aqueous solution of acrylamide and 11.3 parts of a 77.9% aqueous solution of44102030CA 02264803 1999-03-04W0 98/ 14405 PCT/US97/ 16647DEAEA.MeCl were added and mixed. To this mixture, 18 parts ammonium sulfate, 1.08parts citric acid, 0.37 part of 5% EDTA, and 0.9 part glycerol were added and mixed. ThepH of the mixture was about 3.3. The vessel was sealed and sparged with nitrogen for 30minutes, and then polymerization was started by adding 1.3 parts of 1% V-50 at 40°C. Thistemperature was held for 2 hours and then was raised to 50°C and maintained at thistemperature for 8 hours. The residual acrylamide level was about 209 parts per million(ppm). A stable fluid aqueous dispersion was obtained. The bulk viscosity of this dispersionwas about 2,950 cps as measured with a Brookfield Viscometer, No. 4 spindle, 30 rpm at25°C showing preferable fluidity. The dispersion was dissolved to give a SV of 2.47 cps.EXAMPLES 1 05-1 08Polymerizations were carried out in the same manner as Example 104, except thatpart of the poly(DADMAC) was replaced with a poly(DADMAC) polymer having a lowerweight average molecular weight. The effect on the aqueous dispersion bulk viscosity ofincluding the third polymer is shown in Table 8.Table 8% FIRST SECOND SECOND THIRD THIRDTOTAL POLYMER POLYMER POLYMER POLYMER POLYMERNO. SOLIDS % SOLIDS °/o SOLIDS MW °/o SOLIDS MW289,000289,000289,000289,000289,000 10152()CA 02264803 1999-03-04W0 98”"‘“’5 PCT/US97/16647EXAMPLE 109An aqueous dispersion containing 12.5% ammonium sulfate and having a polymersolids of 30%, a bulk viscosity of about 7200 cps and a standard viscosity of about 2.34 cpswas prepared in the same manner as in Example 2.EXAMPLE 1 10An aqueous dispersion containing 15.5% ammonium sulfate and having a polymersolids level of 28%, a bulk viscosity of about 2640 cps and a standard viscosity of about 2.4cps was prepared in the same manner as in Example 9.EXAMPLES 1 1 1-1 33Various amounts of either ammonium sulfate, sodium thiocyanate, or 1,3-benzenedisulfonate (1,3-BDS) were added to the base aqueous dispersions of Example109, Example 110, Example 103, Example 1, Example 102 and Example 142. The bulkviscosities of the resultant aqueous dispersions were further reduced as shown in Table 9.These Examples demonstrate that the bulk viscosity of aqueous dispersions may bereduced by adding salt to the dispersion. and that the addition of 1.3-BDS may be moreeffective than ammonium sulfate on a weight basis. Substantially similar results areobtained by polymerizing the monomers in the presence of the salts.461530CA 02264803 1999-03-04W0 98/14405 PCTIUS97/16647Table 9BV ofExample Base Base °/o Total °/o Total BVNo. Aqueous Aqueous Added Salt Salt Solids (cps)Dispersion Dispersion111 Example 109 7200 (NH4)2SO4 14.21 29.41 2100112 Example 109 7200 (NH4)2SO., 15.86 28.84 1,000113 Example 109 7200 (NH4)2SO,, 17.45 28.3 501114 Example 109 7200 (NH,,)2SO,, 19 27.8 319115 Example 109 7200 1,3-BDS 13.37 29.7 2200116 Example 109 7200 1,3-BDS 14.21 29.41 1160117C Example 109 7200 1,3-BDS 15 29.12 FL118 Example 110 2640 NaSCN 16.3 27.7 540119C Example 110 2640 NaSCN 17.15 27.45 FL120C Example 110 2640 NaSCN 17.96 27.18 FL121 Example 103 8000 1,3-BDS 19.6 24.51 1660122 Example 103 8000 1,3-BDS 21.15 24.04 762123 Example 103 8000 1,3-BDS 22.64 23.58 FL124 Example 103 8000 (NH4)2SO,, 19.6 24.51 3440125 Example 103 8000 (NH4)2SO4 21.15 24.04 1990126 Example 103 8000 (NH4)2SO4 22.64 23.58 1300127 Example 103 8000 (NH4)2SO4 24.07 23.15 982128 Example 1 2300 (NH,,)2SO4 19 27.8 501129 Example 102 2200 (NH.,)2SO4 19.6 24.51 1002130 Example 102 2200 (NH,,)2SO4 21.15 14.04 441131 Example 102 2200 (NH4)2SO., 22.64 23.58 301132 Example 102 2200 (NH4)9SO4 24.07 23.15 200133 Example 142 10,000 (NH4)2SO4 24.07 23.15 1380C: ComparativeFL: Formed Layers471015203035CA 02264803 1999-03-04W0 98/144” PCT/US97/16647EXAMPLE 134About 18 parts of the aqueous dispersion of Example 49 and about 20 parts of theaqueous dispersion of Example 91 were intermixed with stirring. The resultant aqueousdispersion blend was stable and very uniform with a bulk viscosity of about 880 cps.demonstrating that differently charged dispersions may be blended to prepare an aqueousdispersion having an intermediate charge. The aqueous dispersion blend had an overallcharge of about 40% and a SV of 2.5 cps.EXAMPLE ‘1 35About 18 parts of a high charge aqueous dispersion prepared as in Example 48and about 18 parts of a low charge aqueous dispersion prepared as in Example 101 wereintermixed with stirring. The resultant aqueous dispersion blend was stable and veryuniform with a bulk viscosity of about 2300 cps, demonstrating that differently chargeddispersions may be blended to prepare an aqueous dispersion having an intermediatecharge. The resultant aqueous dispersion contained four different polymers.EXAMPLE 136 (Comparative)A polymerization was conducted in the same manner as Example 9, except that theDEAEA.DMS was replaced with an equal weight of DMAEA.MeCl. During the process ofpolymerization, the contents of the vessel became so viscous that stirring becameimpossible. The product was obtained as a gel without fluidity. This Example demonstratesthat replacement of DMAEA.MeCl with DEAEADM8 results in an aqueous dispersionhaving a dramatically lower bulk viscosity.EXAMPLE 137 (Comparative)A polymerization was conducted in the same manner as Example 50, except thatthe DEAEADMS was replaced with an equal weight of DMAEA.MeCl. During the processof polymerization, the contents of the vessel became so viscous that stirring becameimpossible. The product was obtained as a gel without fluidity. This Example demonstratesthat replacement of DMAEA.MeCl with DEAEA.DMS results in an aqueous dispersionhaving a dramatically lower bulk viscosity.481020 ‘3035CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647EXAMPLE 138 (Comparative)A polymerization was conducted in the same manner as Example 91, except thatthe DEAEA.DMS was replaced with an equal weight of DMAEA.MeCl. During the processof polymerization, the contents of the vessel became so viscous that stirring becameimpossible. The product was obtained as a gel without fluidity. This Example demonstratesthat replacement of DMAEA.MeCl with DEAEA.DMS results in an aqueous dispersionhaving a dramatically lower bulk viscosity.EXAMPLE 139 (Comparative)A polymerization was conducted in the same manner as Example 100, except thatthe DEAEA.DMS was replaced with an equal weight of DMAEA.MeCl. During the processof polymerization, the contents of the vessel became so viscous that stirring becameimpossible. The product was obtained as a gel without fluidity. This Example demonstratesthat replacement of DMAEA.MeCl with DEAEA.DMS results in an aqueous dispersionhaving a dramatically lower bulk viscosityEXAMPLE 140A suitable vessel equipped with a mechanical stirrer, reflux condenser, and nitrogeninlet tube was charged with 20 parts deionized water and 10.51 parts of a 40% aqueoussolution of poly(DMAEM.MeCl), weight average molecular weight about 210,000. Aftercompletion of dissolution, 6.57 parts of a 53.27% aqueous solution of acrylamide, 14.56parts of an 80% aqueous solution of DMAEA.MeCl and 4.15 parts of a 80% aqueoussolution of DMAEA.BzCl were added and mixed. To this mixture, 10.8 parts ammoniumsulfate, 0.4 parts citric acid, and 1.51 parts of 1% EDTA were added and mixed. The pHof the mixture was about 3.3. The vessel was sealed and sparged with nitrogen for 30minutes, and then polymerization was started by adding 1.08 parts of 1% V-50. Thereaction mixture was raised to 40°C for 2 hours by placing the vessel in a water bath andthen raised to 50° C for 6 hours. The conversion was greater than 99%. A stable fluidaqueous dispersion was obtained. The bulk viscosity of this dispersion was about 2000 cpsshowing preferable fluidity as measured with a Brookfield viscometer No. 4 spindle, 30 rpmat 25°C. The dispersion was dissolved to give a SV of 2.2 cps.4910D?‘U:203035WO 98114405CA 02264803 1999-03-04EXAMPLES 141 -144PCTIUS97/ 16647Polymerizations were carried out in the same manner as Example 140. The effectof the composition of the first polymer (given in terms of % AMD, % DMAEA.MeCl, andDMAEA.BzCl in monomer feed) and molecular weight of the poly(DMAEM.MeCl) on theaqueous dispersion bulk viscosity is shown in Table 10.N0.140141142143144%AMI) DM/\EA.MeCl60606060609}25252525Table 10% FIRST‘7( TOTAL POLYMERDMAEILBZCI SOLIDS L/C SOLIDS15 25 1815 25 1815 25 1815 25 1825 19SECONDPOLYMER% SOLIDSSECONDPOLYMERMW210,000500,0001 500.000800,000200,000 EXAMPLES 145-1 50 (Comparative)‘V: BV SVSALT (cps)tcps)18 2,000 2.218 13,200 2.3418 10,000 2.418 11,500 2.218 8,680 2.59Polymerizations were carried out in the same manner as Example 140 at differentratios of AMD/DMAEA.MeCl/DMAEA.BzC|/DEAEA.DMS except that the poly(DMAEM.MeCl)was omitted. During the polymerization process, the contents of the vessel became veryviscous to the point that stirring became impossible. The resulting polymerization productwas obtained as a clear gel, a homogeneous composition without fluidity as shown in Table11.50101520253035CA 02264803 1999-03-04W0 98/14405PCT/US97/16647Table 1 1'7: ‘/c ‘/1 ‘7: %N(). DMAEA.McCl DMAEA.BzCl DEAEADMS SOLIDS SALT145C 50 40 10 14.4 20146C 45 40 15 14.4 20147C 60 . . 18 18148C 60 . 18 18149C 55 .. ' 18 18150C 55 - 25 18C: ComparativeEXAMPLES 1 51 -1 53An aqueous dispersion having a bulk viscosity of about 3570 cps was prepared inthe same manner as Example 13. The dispersion was concentrated by placing about 135parts into a suitable vessel and heating to 45°C under flowing nitrogen. A total of 26 partsof water was removed in two stages by this dehydration process. The aqueous dispersionremained stable demonstrating that dehydration is effective for achieving high solids, lowbulk viscosity aqueous dispersions as shown in Table 12.Table 12Polymer BulkExample No. §om_s_(?@) Vi i151 (as polymerized) 28.0 3570152 31.5 660153 34.6 3260102030CA 02264803 1999-03-04“'0 98’1‘“°5 PCT/US97/16647EXAMPLE 154A suitable vessel equipped with a mechanical stirrer, reflux condenser, and anitrogen inlet tube was charged with 277.75 parts deionized water and 112.0 parts of a 40%aqueous solution of poly(DMAEM.MeCl), weight average molecular weight about 200,000.After completion of dissolution, 89.03 parts of a 53.64% aqueous solution of acrylamide,and 164.93 parts of an 80% solution of DEAEA.DMS were added and mixed. To thismixture, 124.0 parts ammonium sulfate, 9.36 parts citric acid, and 5.02 parts of a 10/0solution of EDTA were added and mixed. The pH of the mixture was about 3.3. Thecontents were heated to 48° C and sparged with nitrogen for 30 minutes, and thenpolymerization was started by adding 17.92 parts of 1% aqueous solution of V-50. Thereaction mixture was maintained at 48° C for 5 hours. About 3.5 hours into thepolymerization the aqueous dispersion bulk viscosity began to noticeably increase. The finalbulk viscosity of the aqueous dispersion was about 8,000 cps as measured with aBrookfield Viscometer No. 4 spindle, 30 rpm at 25° C.EXAMPLE 1 55-1 56Duplicate polymerizations ware carried out in a similar manner to Example 154except that an additional amount of ammonium sulfate (4% on total) was addedapproximately 3 hours after initiation of polymerization. This prevented any substantialincrease in bulk viscosity during the polymerization and resulted in a final bulk viscosity thatwas lower than the bulk viscosity obtained in Example 154 as shown in Table 13.Table 13Example No. Final Bulk Viscositv (#4 spindle. 30 rprm155 300 cps156 500 cps521020CA 02264803 1999-03-04WO 98/14405PCT/U S97/ 16647EXAMPLES 1 57-1 72General Polymerization Procedure: The following components were mixed togetherin a suitable vessel and the pH was adjusted to about 3.5 with a 28 wt. % solution ofammonium hydroxide.Acrylamide (55.5 wt. %)DEAEA.DMS (80 wt. °/0)Citric acidAmmonium sulfatepo|y(DMAEM.MeCI) (40 wt. %, 200,000 MW)Deionized WaterV-50 (1 wt. %)EDTA (1 wt. %)Methyienebisacrylamide (MBA)Lactic acid (chain transfer agent)5.34 parts1035 parts0.58 parts7.78 parts7.03 parts16.22 parts1.12 parts1.57 partsvariablevariableForty parts of the solution were placed into a suitable vessel and the solution wassparged with nitrogen. The vessel was sealed and placed into a 40°C water bath for 2hours. The temperature was then increased to 50°C and maintained for an additional 3hours. Results are summarized in Table 14, showing that substantial levels of branchingagent and chain transfer agent can be incorporated into aqueous dispersions of water-soluble and water—swe|lable polymers. The aqueous viscosity values were obtained bydissolving or dispersing the aqueous dispersions in the same general manner as for thestandard viscosity values described above, except that the polymer concentration was 0.135wt. °/o.531015202530CA 02264803 1999-03-04wo 93/14405 PCT/US97/16647Table 14Dispersion buikLactic acid (wt. % MBA (ppm on viscosity (#4 Aqueous ViscosityEx. No. on monomer) monomer) spindle, 30 rpm)157 0 O - 3.91158 0.4 0 - 3.41159 0.8 0 - 3.04160 0 0 1 100 3.71161 0 2 1000 3.61162 0 4 1600 3.66163 0 6 2500 3.31164 O 0 2200 3.11165 0 10 3300 1.90166 0 15 3300 1.77167 O 20 8100 1.67168 0 0 1200 2.81169 0 30 1800 1.46170 0 40 3500 1.43171 O 50 1.44172 O 100 1.28EXAMPLE 1 73A aqueous dispersion was prepared as in Example 155. The aqueous dispersionhad a bulk viscosity of about 240 cps and an aqueous viscosity (obtained as in Examples157-172) of 3.55 cps.EXAMPLE 174The aqueous dispersion of Example 173 was spray—dn'ed on a commercially availablelaboratory spray dryer. The chamber of the laboratory spray dryer was 760 millimeters (mm)in diameter with a 860 mm vertical side and a 65 degree conical bottom. Nominal gas flow5410203035CA 02264803 1999-03-04W0 98/14405 PCT/U S97/ 16647through the dryer was about 180 cubic meters per hour. The aqueous dispersion feed was fedat the center of the top of the chamber using a variable speed pump, through a two—fluid nozzleusing air for atomization. The outlet gas temperature was 86°C and controlled by varying theinlet gas temperature (169° C) and the feed rate (60 milliliters/minute). To provide an inertatmosphere, the spray-dryer was supplied with nitrogen gas from a cryogenic storage tank. Thedried polymer product was discharged through the bottom of the dryer cone to a cyclone wherethe dry product was removed and collected. Residence time in the dryer was about 14seconds. The resultant spray-dried polymer particles, which had a volatiles content of 3.4% anda bulk density of about 0.50 grams per cubic centimeter (g/cc), were readily soluble in waterand had a SV a 3.49 cps.EXAMPLE 1 75The dissolution rate of the spray-dried polymer of Example 174 was compared toa dry polymer of similar composition obtained by spray-drying a commercial water-in-oilemulsion. Solutions were prepared in a wide mouth quart jar using a 2.5 inch magneticstirring bar. The stirring rate was adjusted so that a deep vortex was obtained in the water.The dry polymer was added slowly over a period of 5 minutes at the edge of the vortex toavoid clumping. The spray-dried polymer of Example 174 wet more readily and completelydissolved over a period of 30-40 minutes, giving a clear solution. in contrast, the drypolymer obtained by spray-drying an inverse emulsion did not wet as rapidly and was notcompletely dissolved after two hours. This Example demonstrates that a dry polymerobtained by spray-drying an aqueous dispersion oi the instant invention dissolved fasterthan a dry polymer obtained by spray-drying a corresponding water-in-oil emulsion.EXAMPLE 1 76CThe procedure of U.S. Patent No. 5,403,883 Example 1 was followed. A dispersionhaving a bulk viscosity of about 10,600 cps (#4 spindle, 30 rpm) was obtained.EXAMPLE 177The procedure of U.S. Patent No. 5,403,883 Example 1 was followed, except thatthe 2—trimethlyammoniumethy| acrylate chloride was replaced by an equal weight of1015202530CA 02264803 1999-03-04“'0 98’1‘“°5 PCT/US97/16647DEAEA.MeCl. The resulting aqueous dispersion had a bulk viscosity of about 6,900 cps(#4 spindle, 30 rpm), demonstrating improved bulk viscosity as compared to Example 176C.EXAMPLE 1 78A suitable vessel equipped with a mechanical stirrer, reflux condenser, and a nitrogen inlettube was charged with 22.94 parts deionized water and 10.5 parts of a 40% aqueoussolution of po|y(DMAEM.MeCI), weight average molecular weight about 245,000. Aftercompletion of dissolution, 6.47 parts of a 54.20% aqueous solution of acrylamide, and 7.49parts of the propyl chloride quaternary salt of dimethylaminoethyl acrylate were added andmixed. To this mixture, 10.8 parts ammonium sulfate, 0.7 parts citric acid, and 0.76 partsof a 2% solution of EDTA were added and mixed. The pH of the mixture was about 3.3. Thevessel was sealed and sparged with nitrogen for 30 minutes. and then polymerization wasstarted by addition of 0.54g of 2% aqueous solution of V-50. The reaction mixture washeated to 40°C for 2 hours and then raised to 50° C and held for an additional 4 hours. Theconversion was greater than 99%. A stable fluid aqueous dispersion was obtained. Thebulk viscosity of the aqueous dispersion was about 1300 cps showing preferable fluidity asmeasured with a Brookfield viscometer, No. 4 spindle, 30 rpm at 25° C. The aqueousdispersion was dissolved to give a SV of 2.1 cps. This Example demonstrates that, despiteComparative Example 1 of EP 0 525 751 A1. an aqueous dispersion may be formed whenthe first polymer contains recurring units of the propyl chloride quaternary salt ofdimethylaminoethylacrylate.EXAMPLE 1 79An aqueous dispersion was prepared in a similar manner to Example 40 except thatthe first polymer composition was AMD/DEAEA.DMS/DMAEA.MeCl (60/30/10 mole). Theaqueous dispersion had a bulk viscosity of about 3,600 cps (No. 4 spindle, 30 rpm at 25°C) and a SV of 2.64 cps.EXAMPLE 180An aqueous dispersion was prepared in a similar manner to Example 40 except thatthe first polymer composition was AMD/DEAEA.DMS/DMAEA.MeCl (60/25/15 mole). Theaqueous dispersion had a bulk viscosity of about 1,000 cps (No. 4 spindle, 30 rpm at 25°C) and a SV of 2.87 cps.1020CA 02264803 1999-03-04W0 98/14405 PCT/US97/16647EXAMPLES 1 81 -261The performance of aqueous dispersions of the instant invention was determinedby measuring free drainage rate and cake solids from dewatered sludge as follows: Twohundred grams of sewage sludge from a municipal waste treatment plant were weighed intoeach of a series of jars. Solutions of the aqueous dispersions and of W/O, a commercialwater-in-oil emulsion control (60/40 mole % AMD/DMAEA.MeCl), were prepared so that theconcentration of the polymer was about 0.2%. Various doses of the polymer solutions wereintermixed with the sludge samples and agitated at 500 rpm for 10 seconds (500 rpm/10seconds) or at 1000 rpm for 5 seconds (1000 rpm/5 seconds) with an overhead mixer. Theresultant aqueous mixture of flocculated sludge was dewatered by pouring it into a Buchnerfunnel containing a 35 mesh stainless steel screen; the free drainage was determined bymeasuring the milliliters of filtrate collected in 10 seconds. Cake solids were determinedby drying the pressed sludge at 105°C. The results are shown in Table 15, with eachpolymer identified by previous Example No., free drainage in units of milliliters/10 seconds,mixing in rpm/seconds, dosage in units of pounds of polymer per ton of dry sludge, andcake solids as a weight percent of dry solids in wet cake. The notation “N/A” in the Tablemeans that an accurate cake solids value could not be obtained. These Examples show thatthe performance of the aqueous dispersions of the instant invention is substantiallyequivalent or superior to a comparable commercial product.57152025303540CA 02264803 1999-03-04W0 98/14405PCT/US97/16647Table 15Free Cgkgfig. Pol mer Mixing Dggage Drainage §o|id§ (°/o)181 102 500/10 24.4 137 17.3182 102 500/ 1 0 26.7 140 16.9183 102 500/10 28.9 128 17.1184 103 500/10 20 138 15.8185 103 500/10 22.2 155 16.5186 103 500/ 1 0 24.4 158 16.5187 103 500/10 26.7 162 15.7188C W/O 500/10 24.4 112 15.01890 W/O 500/10 26.7 122 15.6190C W/O 500/10 28.9 114 15.2191 102 1000/5 20.2 142 15.5192 102 1000/5 22.2 145 15.8193 102 1000/5 26.7 140 15.3194 103 1000/5 24.4 130 15.7195 103 1000/5 26.7 138 15.8196 103 1000/5 28.9 145 15.2197C W/O 1000/5 22.2 112 16.0198C W/O 1000/5 24.4 120 16.21990 W/O 1000/5 26.7 110 15.7200 9 500/10 23 144 16.6201 9 500/10 27.2 160 17.0202 9 500/10 31.4 140 17.1203 179 500/10 23 144 17.0204 179 500/10 27.2 153 17.6205 179 500/10 31.4 152 17.4206 180 500/10 23 100 16.9207 180 500/ 1 0 27.2 130 16.8208 180 500/10 31.4 125 17.15820I‘-J’JI303540CA 02264803 1999-03-04WO 98/14405PCT/US97/16647209C W/O 500/10 23 99 14.9210C W/O 500/10 27.2 92 15.2211 9 1000/5 25.1 96 17.6212 9 1000/5 29.3 97 18.0213 9 1000/5 31.4 93 17.9214 179 1000/5 29.3 107 17.7215 179 1000/5 31.4 92 18.4216 179 1000/5 35.6 104 18.7217 180 1000/5 25.1 84 16.9218 180 1000/5 29.3 92 17.9219 180 1000/5 31.4 136 17.1220 180 1000/5 35.6 104 17.1221C W/O 1000/5 25.1 110 16.1222C W/O 1000/5 29.3 112 16.5223C W/O 1000/5 31.4 108 16.8224 44 500/10 22.1 140 17.5225 44 500/10 24.5 138 17.0226 44 500/10 27 139 17.4227 44 1000/5 22.1 120 19.0228 44 1000/5 25.8 117 19.3229 44 1000/5 29.4 104 19.5230C W/O 500/10 18.4 108 NA231C W/O 500/10 22.1 110 NA232C W/O 500/10 25.8 66 NA233C W/O 1000/5 22.1 128 17.9234C W/O 1000/5 25.8 102 17.6235 61 500/10 16.9 130 17.2236 61 500/10 18.6 140 18.0237 61 500/10 21.9 130 17.3238 67 500/10 15.2 80 16.859152025303540W0 98/ 14405CA02264803 1999-03-04PCT/US97/16647239 67 500/10 16.9 105 17.8240 67 500/10 18.6 126 18.2241C W/O 500/10 15.2 116 16.2242C W/O 500/10 16.9 116 15.6243C W/O 500/10 18.8 82 15.4244 140 500/1 0 26.5 138 18.0245 140 500/10 29.4 140 18.5246 140 500/10 32.4 130 18.2247 140 1000/5 29.2 118 17.8248 140 1000/5 32.4 129 18.4249 140 1000/5 35.7 137 19.0250 142 500/10 26.5 120 16.9251 142 500/10 29.4 142 17.2252 142 500/10 32.4 127 17.1253 142 1000/5 25.9 120 17.3254 142 1000/5 29.2 140 17.8255 142 1000/5 32.4 138 18.3256C W/O 500/10 14.7 76 14.0257C W/O 500/10 17.6 114 14.8258C W/O 500/10 20.6 105 14.8259C W/O 1000/5 22.7 104 16.8260C W/O 1000/5 25.9 134 16.3261C W/O 1000/5 29.2 113 16.70: ComparativeW/O: Commercially available water-in-oil emulsion copolDMAEA.MeCl (60/40 mole °/o)60ymer of acrylamide and10l\)‘J130CA 02264803 1999-03-04WO 98/14405 PCT/US97/16647EXAMPLES 262-263The performance of the aqueous dispersions of Examples 118 and 121 isdetermined by measuring free drainage rate and cake solids from dewatered sludge byfollowing the procedure of Examples 181-261. Similar results are obtained.EXAMPLE 264A solution of the spray-dried polymer of Example 174 is prepared so that theconcentration of the polymer is about 0.2%. The performance is determined by measuringfree drainage rate and cake solids from dewatered sludge by following the procedure ofExamples 181-261. Similar results are obtained.EXAMPLES 265-277Solutions of the aqueous dispersions and spray-dried polymers of Examples 9, 44,61, 67, 102, 103, 118, 121, 140, 142, 174, 179, and 180 are prepared so that theconcentration of the polymer is about 0.2%. The performance is determined by measuringfree drainage rate by following the procedure of Examples 181-261, except that a 1%suspension of paper solids is dewatered instead of sewage sludge. Similar results areobtained.EXAMPLES 278-293Aqueous admixtures are prepared by intermixing the aqueous dispersions ofExamples 157-172 with water so that the concentration of the polymer is about 0.2%. Theperformance is determined by measuring free drainage rate by following the procedure ofExamples 181-261, except that a 1% suspension of paper solids is dewatered instead ofsewage sludge. Similar results are obtained.61

Claims (23)

We Claim:

1. A composition comprising an aqueous dispersion comprised of:

(a) a first cationic water-soluble or water-swellable polymer; and (b) at least one second water-soluble polymer different from said first polymer; and (c) a kosmotropic salt; and (d) a chaotropic salt or an anionic organic salt, wherein the amounts of said (b), (c) and (d) are such that a homogeneous composition is obtained in the absence of said (b).

2. A composition comprising an aqueous dispersion comprised of:

(a) a discontinuous phase containing polymer that is comprised predominately of a first cationic water-soluble or water-swellable polymer having at least one recurring unit of the formula (I) wherein R, is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is a methyl, ethyl, or propyl group, X is a counterion, and R2, R3 and R4 together contain a total of at least 4 carbon atoms; and (b) at least one second water-soluble polymer different from said first polymer.

3. A composition comprising an aqueous dispersion comprised of:

(a) a discontinuous phase containing polymer that is comprised predominately of a first cationic water-soluble or water-swellable polymer having at least one recurring unit of the formula (1), wherein R. is H or CH3, A is O or NH. B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons. R2 is a methyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R2 is an alkyl or substituted alkyl group having from 1 to 10 carbons, or an aryl or substituted aryl group having from 6 to 10 carbons. X is a counterion, and R2 R3 and R2 together contain a total of at least 4 carbon atoms: and (b) at least one second water-soluble polymer different from said first polymer, wherein a homogeneous composition is obtained in the absence of said (b).

4. A composition as claimed in Claim 2 or 3 which is further comprised of an inorganic salt selected from the group consisting of chlorides. sulfates, phosphates, hydrogenphosphates and mixtures thereof.

5. A composition as claimed in Claim 2. 3 or 4 wherein said first polymer is further comprised of hydrophobic recurring units.

6. A process which comprises polymerizing vinyl-addition monomers to form an aqueous dispersion comprised of a first cationic water-soluble or water-swellable polymer, wherein said polymerizing is carried out in the presence of an aqueous composition comprised of (a) at least one second water-soluble polymer different from said first polymer; and (b) a kosmotropic salt; and (c) a chaotropic salt or anionic organic salt, wherein the amounts of said (a), (b) and (c) are such that a homogeneous composition is obtained if said polymerizing is carried out in the absence of said (a).

7. A process which comprises polymerizing vinyl-addition monomers comprised of at least one monomer of the formula (II) to form an aqueous dispersion comprised of a first cationic water-soluble or water-swellable polymer, wherein R, is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is a methyl, ethyl, or propyl group, X is a counterion, and R2, R3 and R4 together contain a total of at least 4 carbon atoms; and wherein said polymerizing is carried out in the presence of an aqueous composition comprised of at least one second water-soluble polymer different from said first polymer.

8. A process which comprises polymerizing vinyl-addition monomers comprised of at least one monomer of the formula (II) to form an aqueous dispersion comprised of a first cationic water-soluble or water-swellable polymer, wherein R1 is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is an alkyl or substituted alkyl group having from 1 to 10 carbons, or an aryl or substituted aryl group having from 6 to 10 carbons, X is a counterion, and R2, R3 and R4 together contain a total of at least 4 carbon atoms; and wherein said polymerizing is carried out in the presence of an aqueous composition comprised of an amount of at least one second water-soluble polymer different from said first polymer; and wherein said amount of said second polymer is such that a homogeneous composition is obtained if said polymerizing is carried out in the absence of said second polymer.

9. A process as claimed in Claim 7 or 8 wherein said aqueous composition is further comprised of an inorganic salt selected from the group consisting of chlorides, sulfates, phosphates, and hydrogenphosphates.

10. A process as claimed in Claim 7, 8 or 9 wherein said vinyl-addition monomers are further comprised of a hydrophobic monomer.

11. A method comprising (a) intermixing an aqueous dispersion of polymers, or aqueous admixture thereof, in an amount effective for dewatering, with a suspension of dispersed solids, and (b) dewatering said suspension of dispersed solids, said aqueous dispersion being comprised of (i) a first cationic water-soluble or water-swellable polymer; and (ii) at least one second water-soluble polymer different from said first polymer; and (iii) a kosmotropic salt; and (iv) a chaotropic salt or anionic organic salt, wherein the amounts of said (ii), (iii) and (iv) are such that a homogeneous composition is obtained in the absence of said (ii).

12. A method comprising (a) intermixing an aqueous dispersion of polymers, or aqueous admixture thereof, in an amount effective for clarification, with oil-containing water to produce clarified water, and (b) separating said clarified water from said oil, said aqueous dispersion being comprised of (i) a first cationic water-soluble or water-swellable polymer; and (ii) at least one second water-soluble polymer different from said first polymer; and (iii) a kosmotropic salt; and (iv) a chaotropic or anionic organic salt, wherein the amounts of said (ii), (iii), and (iv) are such that a homogeneous composition is obtained in the absence of said (ii).

13. A method comprising (a) intermixing an aqueous dispersion of polymers, or aqueous admixture thereof, in an amount effective for dewatering, with a suspension of dispersed solids, and (b) dewatering said suspension of dispersed solids, said aqueous dispersion being comprised of (i) a discontinuous phase containing polymer that is comprised predominately of a first cationic water-soluble or water-swellable polymer having at least one recurring unit of the formula (I), wherein R is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons. R2 is a methyl, ethyl. or propyl group, R3 is a methyl, ethyl or propyl group, R4 is a methyl, ethyl. or propyl group, X is a counterion, and R2, R3 and R4 together contain a total of at least 4 carbon atoms: and (ii) at least one second water-soluble polymer different from said first polymer.

14. A method comprising (a) intermixing an aqueous dispersion of polymers, or aqueous admixture thereof, in an amount effective for clarification, with oil-containing water to produce clarified water. and (b) separating said clarified water from said oil, said aqueous dispersion being comprised of (i) a discontinuous phase containing polymer that is comprised predominately of a first cationic water-soluble or water-swellable polymer having at least one recurring unit of the formula (I), wherein R1 is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is a methyl, ethyl, or propyl group, X is a counterion. and R2, R3 and R4 together contain a total of at least 4 carbon atoms; and (ii) at least one second water-soluble polymer different from said first polymer.

15. A method comprising (a) intermixing an aqueous dispersion of polymers, or aqueous admixture thereof, in an amount effective for dewatering, with a suspension of dispersed solids, and (b) dewatering said suspension of dispersed solids, said aqueous dispersion being comprised of (i) a discontinuous phase containing polymer that is comprised predominately of a first cationic water-soluble or water-swellable polymer having at least one recurring unit of the formula (I), wherein R1 is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is an alkyl or substituted alkyl group having from 1 to 10 carbons, or an aryl or substituted aryl group having from 6 to 10 carbons. X is a counterion, and R2, R3 and R4 together contain a total of at least 4 carbon atoms; and (ii) at least one second water-soluble polymer different from said first polymer, wherein a homogeneous composition is obtained in the absence of said (ii).

16. A method comprising (a) intermixing an aqueous dispersion of polymers, or aqueous admixture thereof, in an amount effective for clarification, with oil-containing water to produce clarified water, and (b) separating said clarified water from said oil. said aqueous dispersion being comprised of (i) a discontinuous phase containing polymer that is comprised predominately of a first cationic water-soluble or water-swellable polymer having at least one recurring unit of the formula (I), wherein R1 is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl, ethyl, or propyl group, R4 is an alkyl or substituted alkyl group having from 1 to 10 carbons, or an aryl or substituted aryl group having from 6 to 10 carbons, X is a counterion, and R2, R3 and R4 together contain a total of at least 4 carbon atoms; and (ii) at least one second water-soluble polymer different from said first polymer, wherein a homogeneous composition is obtained in the absence of said (ii).

17. A method as claimed in Claim 13, 14, 15 or 16 wherein said aqueous dispersion is further comprised of an inorganic salt selected from the group consisting of chlorides, sulfates, phosphates, hydrogenphosphates and mixtures thereof.

18. A method as claimed in Claim 13, 14, 15, 16 or 17 wherein said first polymer is further comprised of hydrophobic recurring units.

19. A method as claimed in Claim 11, 13 or 15 wherein said suspension comprises paper solids, mineral solids, food solids, or a biologically treated suspension.

20. A process for producing substantially dry water-soluble or water-swellable vinyl-addition polymer particles comprising (a) spray-drying a vinyl-addition polymer-containing aqueous dispersion into a gas stream with a residence time of about 8 to about 120 seconds and at an outlet temperature of about 70° C to about 100° C and (b) collecting resultant polymer particles.

21 . A composition comprising substantially dry water-soluble or water-swellable polymer particles comprised of (a) a first cationic water-soluble or water-swellable polymer; and (b) at least one second water-soluble polymer different from said first polymer; and (c) a kosmotropic salt; and (d) a chaotropic salt or an anionic organic salt, wherein about 90% or more of said polymer particles each individually contains both said (a) and said (b), said particles having a bulk density of about 0.4 grams per cubic centimeter to about 1.0 grams per cubic centimeter.

22. A composition comprising substantially dry water-soluble or water-swellable polymer particles comprised of (a) a first cationic water-soluble or water-swellable polymer having at least one recurring unit of the formula (I), wherein R1 is H or CH3, A is O or NH, B is an alkylene or branched alkylene or oxyalkylene group having from 1 to 5 carbons, R2 is a methyl, ethyl, or propyl group, R3 is a methyl.
ethyl, or propyl group, R4 is an alkyl or substituted alkyl group having from 1 to 10 carbons, or an aryl or substituted aryl group having from 6 to 10 carbons, X is a counterion, and R2, R3 and R4 together contain a total of at least 4 carbon atoms; and (b) at least one second water-soluble polymer different from said first polymer, wherein about 90% or more of said polymer particles each individually contains both said (a) and said (b), said particles having a bulk density of about 0.4 grams per cubic centimeter to about 1.0 grams per cubic centimeter.

23. A method comprising (a) intermixing the composition of Claim 21 or 22 with water to form an aqueous polymer admixture, (b) intermixing said aqueous polymer admixture, in an amount effective for dewatering, with a suspension of dispersed solids, and (c) dewatering said suspension of dispersed solids.