CA1161197A - Emulsion copolymer anion exchange resins and ion exchange process therewith - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

According to one aspect of the invention as disclosed, emulsion copolymer particles with diameters smaller than 1.5 micrometers and functionalized with cation exchange functional groups are prepared and suspended as emulsions in liquid media to form liquid cation exchange materials.
Also, emulsion copolymer particles with diameters than 1.5 micrometers are functionalized with anion exchange functional groups by a method involving coagulation of the emulsion, according to another aspect of the invention disclosed herein. Both weakly basic and strongly basic anion exchange resins are prepared from aromatic or acrylic copolymers, and the emulsion may be resuspended to form anion exchange emulsions. Additionally, by a further aspect of the invention as disclosed, ions are exchanged between emulsion ion exchange resins and conventional ion exchange resins during both batch and column contact. This process may be used to place the emulsion resin or the conventional resin in the desired ionic form.

Description

a ~ 7 ION E~C~NGE PROCESS INVOLVING EMULSION
~ XCPlAM~E ~S ~
Back round of the Invention The present invention concerns fine-particle-size ion exchange resins and methods ~or their preparation.
In particular it concerns spherical, crosslinked emulsion copolymer particles in a size range of from about 0.01 to about 1.5 micrometers in diamet~r, which bear ion exchange functional groups, and emulsions of these particles. It fur~her concerns the preparation of these par~icles and emulsions, and the use of ~hese par~icles and emulsions in removing dissolved and undissolved material from liquids.
;` Finely divided ion exchange materials have been used ex~ensively as fil~er media for the ~imul~aneous fil~ration and deionization of condensate water from steam ~urbine generators, and to a lesser extent in pharmaceutical applications ~uch as druy carriers and tablet disintegrators, and in other commercial applications.
In the past such finely divided ion exchange materials have been produced by grinding or otherwise physically reducing the size of ion exchange particles produced by conventional processes involving the separa~e `~ 25 ~teps of polymerizati~n -- most commonly suspension " polymerization -- and functionalization.

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3 ~B1~97 Schultz and Crook (I & EC Product Research and Development, Vol. 7, pp. 120-125, June, 1968) have produced particles of ground ion exchange resin with average diameters of one micron or smaller, but the particles are not spherical, ana the range of diameters within a given sample of such materials is large, i.e., the particles are not uniformly sized. Even though large particles may constitute only a small ~raction of the total number of ground particles, they represent a much larger fraction of the sample weight. As a result, such ground resins exhibit settling o~ a significant fraction of the ion exchange material weight from aqueous suspension.
Suspension polymerization involves suspendlng droplets of organic liquid containing monomers, polymerization initiators and suspension stabilizers in an aqueous-phase medium. The droplet size, largely a function of agitation rate, controls the final polymer partlcle slze, which normally ranges down to about 40 micrometers, although sizes down to 5 micrometers (US
Patent 3,357,158) or 10 micrometers (US Patent 3,991,017) have been disclosed. Ion exchange materials have also been produced by bulk polymerization.
Physically reduclng the particle size of such polymers in bulk or bead form to sub-mlcron sizes is difficult and expensive, and produces material with undesirable physical characteristics such as irregular particle shape and broad particle-size distribution. It may also produce undesirable heat degradation of the resln.
Sub-micron sized, spherical polymer particles have been prepared in the past, including some with limited ion exchange functionality. These partlcles were ~611~7 prepared ~rom monomers which contained ion exchange functional groups, such as acrylic and methacrylic acld, or dlalkylaminoalkyl acrylates and methacrylates. In most cases the polymerization reaction used was emulsion polymerlzatlon. Thus Haag et al (U.S. Patent 3,847,857) used ~'...from 5 to 70% by weight...of one or more monomers contalning an amlne or quaternary ammonium group..." (column 2, llnes 56-59) in forming a functional, crosslinked emulsion ion exchange resln for use ln palnts and other coatings.
Rembaum et al (U.S. Patent 3,985,632) simllarly prepared chromatographic adsorbents by emulsion polymerizing monomer mixtures containing minor amounts of monomers with amine functlonality (column 5, lines ~5-46). Fitch (U.S. Patent 3,104,231) used up to 15% by weight of monomers containlng carboxylic acid groups when preparing crosslinked emulsion copolymers. He cautions that higher content of such monomers leads "to either solubility of the copolymer in water or dilute alkali or signlflcant swelling of the copolymer in such aqueous media." (column 6, line 70 - column 7, line 4).
Hatch (U.S. Patent 3,957,698) descrlbes a preclpitation polymerization for maklng crosslinked, spherlcal lon exchange resin partlcles in a size range similar to that of emulsion polymer particles. The precipitation process lnherently produces larger particles, in the range of Ool~10 micrometers (compare 0.01-1.5 mm for emulsion polymerization), and involves the precipitation of polymer particles from a monomer-solvent solution in whlch polymer is insoluble. In emulsion polymerization the monomer is only slightly . I

,s soluble in the solvent, and the polymer particles are formed when monomer-swollen soap mlcelles contact solvent-phase-initiated polymer chains. Hatch mentions that "suitable micro bead resins can be prepared by suspension or emulsion polymerization..." He then descrlbes suspension polymerization but fails to indicate any detail of an emulsion polymerization process (column 3~ llnes 30-40). The lon exchange mlcrobeads of Hatch are weak acid resins made from carboxylic acid monomers such as acrylic or methacrylic acid, although the use of esters of these acids ls mentioned, with hydrolysis subsequent to polymerizatlon. Hatch exemplifies the preparation of a microbead from vinylbenzyl chloride (Example 4), but the particle size (3-7 microns) is clearly oul;side the range of the present invention~ and no attempt iB made to impart ion exchange functionality to the microbead itself until it has been incorporated in an ion exchange resin matrix. Hayward (U.S. Patent ~,976,629) also prepared weakly acidic cation exchange resins of a slze "less than 20 microns" uslng a modified suspension polymerization and carboxylic acld monomers.
Tamura (Nippon Kagaku Kaishi 76 (4), pages 654-8, 1976) discloses the preparation of strongly acidic cation exchange resin material from emulsion copolymers. Tamura coagulated styrene-divlnylbenzene copolymer emulslons and functionalized them with fuming sulfuric or chlorosulfuric acids. He subsequently mixed the coagulum into a polypropylene membrane, but 3o dld not teach that the coagulum might be re-emulsified.
The Invention According to this lnvention a novel class of small partlcle-size, spherlcal ion exchange resins, having particle diameters smaller than those hereto~ore known in the art, has been discovered. These resins ~ are prepared ~rom crosslinked emulsion copolymer partlcles, and may possess a degree of functionalization greater than about 0.7, and as high as about 1.5,~ functional groups per monomer unlt. The process by which these resins are prepared involves functionalizatlon of the emulsion copolymer particles wlth weakly acidic, strongly acldic, weakly basic or strongly basic ion exchange functional groups. The emulsion copolymer particles may be ~unctionalized directlyi as by hydrolysis, sul~onation, and similar reactions, or indirectly by such reactions as chloromethylation followed by a functionalization reaction such as amination. To facilitate handling of the particles, the emulsion may be coagulated, and the large coagulum particles handled like large polymer beads for isolation and reaction. Alternatively, the emulsion copolymer particles may be dried prior to functionalizing them. After functionalization the particles may be resuspended as an emulslon oY discrete particles by high-shear mixingl ultrasonic vibration, mild grinding or other comminuting method which disrupts the agglomerated pieces without damaging the spherical particles of the emulsion ion exchange resin.
The ion exchange resins o~ this invention may be prepared in narrow particle-size ranges with mean values in the submicroscopic range (which term, as used herein, means having particle diameters below about 1.5 micrometers), variable from about 0.01 micrometers to about 0.5 micrometers ln diameter, and by the use o~

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- 5a -special techniques, to as large as about 1.5 micrometers ln diameter. They may be prepared as cakion or anion exchange resins, that is, with strongly acidic~ strongly basic, ~eakly acidic or weakly basic functionality.
The invention, in a further aspect, resides in a process for changing the lonic form of a plurality of ion exchange resins of the same ion exchange type, at least one of the resins being in the physical form of approximately spherical, s~bmicroscopic beads and initially belng substantlally in a first ionic form, and the balance of the resins being in the physical form of macrobeads and initlally being substantially in a second ionlc form, which process comprises contacting the macrobeads in the second ionic form with an emulsion of the submicroscopic beads in the first ionic form until ion exchange occurs between the ions of the submlcroscopic beads and the ions of the macrobeads.
This aspect of the invention is disclosed and claimed in Canadian Application No. 335,831 of Berni P. Chong, filed September 18, 1979, of which the present appllcation is a divisional.
In the Drawings:
Figures 1-3 and 4a~4d are electron photomicrographs of typical ion exchange materials of the present invention. Figures 1-3 are photomicrographs of three different sizes of anion exchange emulsion resins in the hydroxyl form, at a magnification of X50,000. Figures 4a-4d are photomicrographs of a single floc at four different ~magnifications; the floc was prepared by mixing a cation exchange emulsion resin with an anlon exchange .

emulsion resin8 Each of the materials shown ln these photomlcrographs was prepared by methods taught herein.
Figure 1 shows a strongly basic anion exchange emulsion resin in the hydroxyl ion f'orm, derived from a ~ copolymer contalnlng 3% (weight) divinylbenzene and prepared according to Example 14 below, coagulated according to Example 2 below, chloromethylated and amlnated according to Example 17 below, and converted to the hydroxyl form accordlng to Example 21 below.
Flgure 2 shows a strongly baslc anion exchange emulsion resin in the hydroxyl ion f'orm, derived from a copolymer containing 3% tweight) dlvlnylbenzene and prepared accordlng to Example 1 below, coagulated according to Example 2 below~ chloromethylated and aminated according to Example 17 below~ and converted to the hydroxyl form accordlng to Example 21 below.
Figure 3 shows the strongly basic anion exchange emulsion resin ln the hydroxyl ion form of Example 21 below.
Flgure 4b shows the floc of Example 22 below at a magnification of X300; Figure 4a shows the same floc at a magniflcation of X1000; Figure 4d shows the same floc at a magniflcation of X3000; and Figure 4c shows the same floc at a magnification of X10,000.
By referring to the particles shown in the figures, it may be seen that these particles are approxlmately spherical, that as prepared they have a relatively narrow partlcle-size dlstribution, and that they may be prepared in diff'erent partlcle sizes. The particles of these figures range in size from about 0.017 micrometers to about 0.45 micrometers.
Although the figures lllustrate strongly basic anion exchange emulsion resins, the particles of other anion exchange emulsion resins~ and of cation exchange emulslon resins, have similar appearances and size distribution.
The aggregations of particles ln these figures were concluded by the laboratory preparing the photomicrogra~hs to be artifacts assoclated with preparation of the samples for mlcrography.
In khe case of strongly acidic and basic, and weakly basic resins, the formation of physlcally stable coa~ula from the crosslinked emulslon copolymers makes posslble the isolation of the copolymers for functionalization. Because of their small particle size the emulsion copolymer particles cannot practically be filtered or otherwise separated from the liquids in which they are prepared, nor coulcl functionalized copolymer particles be separated from the functionalization mlxtures. After coagulation, the large coagulum particles can be filtered and washed in much the same way as ion exchange resin beads of conventional size. Functionalization of the coagulated emulsion copolymer involves conventional reactions well known in this art.
Weakly acidic emulsion copolymer resins have physical properties similar to those of the resins descrlbed aboveS but they need not be coagulated prior to isolation and functionallzation. A preferred method of preparing the weakly acidic resins of thls inventlon lnvolves adding a crosslinked acrylic ester emulsion copolymer to an alkali hydroxide solution. Upon addition the emulsion may coagulate, but as the copolymer ester llnkages are hydrolyzed to form ~ ~61197 carboxylic acid groups in the salt form, any coagulum ~ormed re-suspends to form an emulsion of the salt of the functionaliæed resin. The functlonal groups of the resin may then be converted to the ~ree acid ~orm by treating the emulsion with a conventional, strongly acidic cationlc exchange resin ln the free acid form.
The emulsion copolymer ion exchange resins of thls invention possess the followlng advantageous properties:
(a) regular, generally spherlcal shape, (b) a high degree of structural rigidlty which is controllable by the degree of crosslinking in the emulslon copolymer, (c) a controllable, small particle size, the medlan value of which may be varied from about 0~01 to about 1.5 micrometers, (d) a narrow particle size range; photomicrographic analysis shows ranges typlcally i 9 nanometers of the particle median diameter for about 80% of the particles, (e) a large surface area per unit weight, variable wlth particle diameter from about 4 square meters per gram to as great as about 120 square meters per gram, compared with about 0.1 square meter per gram for typlcal, small-diameter conventional ion exchange resins, (~) a high degree of ion exchange functionality, variable to greater than one functional group per monomer unit, (g) the abllity to form essentially non-settling emulslons~ except in the largest particle slzes, (h) a particle size increase on hydration, controlled .` i . . . ~ . .

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by the degree of crosslinking in the emulslon copolymer, which is variable from about 10% ko about 500% or more of the dry partlcle diameter, (i) water insolubility and negligible water extractability, and desirable sensible properties of (J) subdued ~aste~
(k) ability to mask the taste of materials bound to the resin, (1) a smooth, non~gritty texture to the mouth, and (m) a smooth, non-irritatlng texture to the skin.
The emulsion copolymers from which the ion exchange resin of this invention are derived may be prepared by conventional emulsion polymerizatlon techniques. These techniques typlcally involve~ but are not limited to, polymeriz~ation of an emulsion comprising the monomers and a surface-active agent.
The polymerization is usually initiated by a water-soluble initiator. It is well known that the action of most such initiators is inhibited by the presence o~
oxygen, so oxygen-excluding techniques, such as using lnert gas atmosphere and deoxygenated solutions and emulslons, are pre~erably employed in the polymerization. The choice of surface-active agents and initiators will be apparent to one skllled in this art. The monomers from which the emulsion copolymers are derived comprise a ma~or amount of a monoethylenically unsaturated monomer or mixture of such monomers and a minor amount of a polyethylenically unsaturated monomer or mixture of such monomers which act to crosslink the polymer. The following are examples of monoethylenically unsaturated monomers '~;. i ;

il J 6~ ~7 useful in preparlng the emulsion copolymers: aromatic monomers, lncluding polycyclic aromatic monomers such as vinylnaphthalenes and monocyclic aromatic monomers such as styrene and substituted styrenes, whlch include ` ethylvinylbenzene9 vinyltoluene and vinylbenzyl chlorlde; and acrylic monomers, the esters of methacryllc ænd acrylic acld, such as methyl acrylate, ethyl acrylate, propyl acrylate, lsopropyl acrylate ~ butyl acrylate, tert butyl acrylate, ethylhexyl acrylate, cyclohexyl acrylate, lsobornyl acrylateg benzyl acrylate, phenyl acrylate, alkylphenyl acrylate~
ethoxymethyl acrylate, ethoxyethyl acrylate, ethoxypropyl acrylate, propoxymethyl acrylate, propoxyethyl acrylate, propoxypropyl acrylate~
ethoxyphenyl acrylate, ethoxybenzyl acrylate, and the corresponding methacrylic acld esters.
In the case of the acrylic esters, the pre~erred embodlment employs lower aliphatic esters of acrylic acid in which the allphatic group contains from 1 to 5 carbon atoms. This is a particularly preferred embodiment when the copolymers therefrom are to be employed as intermedlates in the preparation of either carboxylic cation-exchange emulsion copolymer reslns or anion-exchange emulslon copolymer resins. In the preparation of both the carboxylic exchanger and the anlon exchanger, the ester group is replaced. Thus, the practlcal choice is methyl or ethyl acrylate.
Suitable polyunsaturated cross-linking monomers include the following: divinylbenzene, divinylpyridine, divinyltoluenes, divinylnaphthalenes, ethylene glycol dimethacrylate, divinylxylene, divinylethylbenzene, divinylsulfone, divinylketone, , I

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divinylsulfide, trivinylbenzene, trivlnylnaphthalene, trimethylolpropane, trimethacrylate, polyvinylanthracenes and the polyvinylethers of glycol, glycerol, pentaerythritol, and resorcinol.
Particularly preferred cross-linklng monomers include the following: polyvinylaromatic hydrocarbons such as divinylbenzene and trivinylbenzene, glycol dimethacrylates such as ethylene glycol dimethacrylate, and polyvinyl ethers of polyhydric alcohols, such as divinoxyethane and trivinoxypropane. Aqueous emulsion polymerizatlon of mixtures of ethylenically unsaturated monomers are described in United States Patent Nos.

2,753,318 and 2,918,391, among others.
As noted above, emulsion copolymer ion exchange resins of this invention may be prepared with medlan particle diameters ~rom about 0.01 to about 1.5 micrometers; they may also be prepared in a range of preferred median particle diameters from about 0.01 to about 0.5 mlcrometers. The median particle diameter of the resin may be accurately controlled within these ranges, and the distribution of particle diameters about the median value is narrow, far narrower than distributions obtained with comminuted resins of small particle diameter. Control of the resin particle diameter depends on the emulsion copolymer, even though the particle size is increased by functionallzation.
Such control of the emulsion copolymer particle diameter is well known. For example, within the copolymer particle diameter range of about 0.05 to about 0.3 micrometers the size may be controlled by varying the level of surface active agents present in the polymerization mixture, an increase in these agents I

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~ ~6~l97 tending to produce a smaller emulsion copolymer particle. Crosslinker levels in the polymer tend also to exert an effect on copolymer particle diameter; more highly crosslinked copolymer particles 'end not to swell as much when they hydrate as lightly crosslinked particles. Below diameters of about 0.1 mlcrometers special surfa~e active agents may be used to control particle size down to about 0.01 micrometers as illustrated below in Example 14. Copolymer partlcles larger than about 0.3 micrometers may be ~ormed by ~urther reduction of the level of surface active agents, or by growing larger particles from ~Iseed~
particles of pre-formed emulsion copolymers. Polymer particles may be formed in this way to as large as about 1 micrometer in diameter; subsequent functionalization produced ion exchange resin particles with diameters as large as about 1.5 micrometers. The process of making large copolymer particles is illustrated below in Example 13.
Crosslinker levels may be selected between about 0.1% and about 25~, a more preferred range being from about 1% to about 20%. Selection of crosslinker levels depends upon the particular type of resin9 physical properties, and the level of functionali~y desired in the emulsion ion exchange resin product. For example, sulfonlc acid functionalized resins are prepared from emulsion copolymers with higher levels of crosslinker than copolymers for preparing amine functionalized resins. Simllarly, if very low swelllng is deslred, a processing advantage that permits the use of smaller reaction containers, higher crosslinker levels are used. Ranges of about 3% to about 12% crosslinker are .~ I
;~-~B~197 typical for sulfonic acid ~unctionallzed reslns with ` low swelling properties, and higher levels may be used when exceptionally low swelling is desired. Levels above about 25% may be employed for speclal purposes, so long as the crossllnker, as well as the monoethylenically unsaturated monomer, may be functionalize~ to produce a reasonable number of ~unctional groups per monomer unit. Where more rapid kinetics are deslred, lower crosslinker levels are selected. While anion exchange emulslon resins preferably contain crosslinker levels between about 0.1% and about 7% or higher, they more preferably contain from about 0.5% to about 3% crosslinker. The selectlon of speci~ic crosslinker levels to produce the desired balance of physical properties is well known to those skilled with conventional ion exchange resins, and the same guiding princlples are used with emulsion resins.
To permit further handling5 the emulslon copolymer is coagulated using one of several well-known procedures. A preferred coagulation procedure ls to add the emulsion to a hot saline solution; aqueous so~utions at concentrations ~rom saturated to about 2%
~wt) sodium chloride or other inorganic salts such as calcium chloride, aluminum sulfate and others may be used. Aqueous sulfuric acid solutlons, concentrated to about 4% (wt), are also suitable 3 and aqueous alkali hydroxide solutions such as those of potassium or sodium hydroxide are especlally sultable for coagulation and slmultaneous hydrolysis and functionalization of acrylic ester copolymers.
Additlon of the emulsion to the stlrred coagulant ~.

solution allows the coagulum to disperse as particles with size dependent upon the stirring rate, the useful size spans a wide range but for easiest handling should ; not fall below small granules into the powder range.
Addition of the coagulank solution to the emulsion is possible, but tends to produce an unwleldy coagulated mass rather than coagulum particles. The emulsion may also be coagulated by drying it; spray drying is a preferred procedure for the preparation of strongly basic resin product from an aromatic copolymer; the particles produced by this prGcedure tend to be too small for efficient handling when used for functionalization reactions that require subsequent filtration and washing. Other useful procedures for coagulating the copolymer emulslon include vigorous stirring, alternating ~reezing and thawing, and addition of an organic solvent to the emulsion.
Once produced, the coagulum particles are coherent enough to withstand typical handling techniques used in the washing, filtration, and functionalization of conventional, suspension-polymerized ion exchange beads. The coagulum is preferably freed from water by evaporation at ambient or higher temperatures, or by rinsing with a water-mlscible, dry, organic solvent, to prepare it for convention functionalization reactions.
In general the reactions employed to functionalize emulsion copolymer ion exchange resins are the same as those used to produce ion exchange resins from conventional, suspension-polymerized copolymers. As a high degree of functionalization is desirable because it produces a large number of functional ion exchange sites per unit weight of resin, the emulsion ion , j ,_.

11 ~161~97 exchange resins of the present invention are functionalized to between about 0.7 and about 1.5 functlonal groups per monomer unlt. The more preferred range ls ~rom about 0.8 to about 1.2 functional groups per monomer unit. The term, "functional groups per monomer unit"~ as used hereln, refers to the number of ion exchange functional groups per total monomer unitsg both "backbone", monoethylenlcally unsaturated monomer and crosslinklng, polyethylenically unsaturated monomer- For example, in the case of an aromatlc backbone monomer and aromatlc crosslinker monomer used to prepare a copolymer, this term would refer to the number of functlonal groups per aromatlc rlng in the polymer. Similarly, ln the case of a copolymer with a functionalized acryllc backbone and an unfunctionalized aromatic crossllnker, the degree of functlonallzatlon will be the functional lon exchange groups per total monomer unlts, both acryllc and aromatic. The degree of functionalizatlon may be thought of as the number of functional groups per mole of all the monomers which constitute the copolymer. Some of the typical processes for functionallzing the copolymer are lllustrated below.
Strongly acidic emulsion copolymer lon exchange reslns of thls lnvention may be prepared~ for example, by heating coagulum particles of crossllnked styrene or substituted styrene emulsion copolymer with concentrated sulfuric acid to produce a sulfonic acld-functlonalized resin, rlnsing the product free of excess acld wlth water, and re-suspending the coagulated emulsion particles by the processes described above.
i ~61~97 Weakly acidic emulsion copolymer lon exchange resins of thls invention may be prepared, ~or example, by hydrolyzing crossllnked acrylic ester emulsion copolymers with alkali metal hydroxide solutions, to ~orm carboxylic acid-functionalized reslns. It should be noted that this particular procedure does not require that the emulslon be coagulated prior to ~unctionalization; upon addition of the emulslon to the hydroxide solutlon coagulation may occur, but as the ester linkages are hydrolyzed any coagulum of the copolymer resin re-suspends. The carboxylic acid-functionalized resin produced by this procedure ls in the alkali metal form, and may be converted to the free acid (hydrogen) form by contacting it with a conventional, strongly acidic cation resin in the hydrogen form~ Similarly, acrylic ester copolymer resins may be hydrolyzed wlth strong acids to produce carboxylic acid-functionalized resins in the hydrogen ~orm, but in this case the product is a coagulum rather than an emulsion.
Strongly basic emulsion copolymer ion exchange resins of this invention may be prepared, for example, by chloromethylating coagulated particles of crosslinked styrene emulsion copolymer with chloromethyl methyl ether in the presence of a Lewis acid such as aluminum chloride, and treating the resulting intermediate emulsion copolymer material with a tertiary amine such as trimethylamine to form a quaternary amine chloride functional group.
Alternatively, a strongly basic quaternary amihe resln may be prepared by treating a crosslinked acrylic ester emulsion copolymer with a diamine containing both a ` !
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t ~1197 - 17 ~
tertiary amine group and a primarg or secondary amine group, such as dimethylaminopropylamine or di(3-dimethylaminopropyl)amine, and quaternlzing the resulting weakly basic resin with an alkyl halide such as methyl chloride.
Weakly basic emulsion copolymer ion exchange resins of this inventlon are prepared, for example3 in the same manner described for strongly basic resins, except that for a styrene copolymer primary or secondary amines are employed instead of tertiary amines, and for an acrylic ester copolymer the resin ls not quaternized with an alkyl halide.
While the functionalized coagulum particles possess ion exchange properties, and are sufficiently cohesive that they may be used in conventional ion exchange processes in much th~ same manner as conventional resin beads, a preferred form for utilizing the materials of this invention is the re-suspended form. Re-suspension of the functionalized coagulated particles may be achieved by the processes described above, i.e., by high-shear mixing, ultrasonic vibration, mild grinding, or other comminuting method which disrupts the coagulum without damaging the spherical resin particles. Spontaneous resuspension of the emulsion particles occurs during preparation of the strongly basic product from aromatic copolymers under some conditions, eliminating the need for a comminuting step.
It should be noted that the hydrophobic nature of the unfunctionalized emulsion copolymer particies encourages coagulation. Once ~unctionalized the ion exchange resln particles are relatively hydrophllic;

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they tend not to coagulate from emulslon ~orm under the conditions suggested for the unfunctionali%ed copolymer emulsions. Photomicrographic and other physical evldence indicates that the emulsions of the functionalized ion exchange resin particles tend to contain largely indivldual particles. On drying a sample of su~h an emulsion the particles may remain as individual particles, or they may ~orm small, loosely bound clusters of partlcles. These clusters may be disrupted by very mild force - rubbing between the flngers is often sufficient - ln contrast to the tightly bound nature of the coagula. The loose clusters also tend to disperse spontaneously upon additlon to water, to form emulsions of the individual resin particles.
In general, the emulsio~ copolymer ion exchange resins of this invention may be used in any applicatlon where ground lon exchange resins, produced by bulk or suspension polymerization, are used, but because of the special properties of the reslns of this invention, they o~ten prove superior to ground resins. In addition, these special properties permit resins of this invention to be used for a wide variety of applications where ground resins are unsuitable.
Among the uses for the resins o~ this invention are those as orally administered medicines or medical treatments~ These include the use of the weakly acidic resins in the calcium or magnesium form as gastric antacids, of the strongly acidic resins in the sodium form ln treating hyperkalemia, of the strongly acidic resins in the calcium form or the strongly basic resins in the chloride form in treatlng hypercholesterolemia, ~,r :f`~

116t19~

and of the weakly acldic resins ln the calcium rorm ln treating gallstones. ~urther such uses are as drug carrlers and sustained release agen~s for drugs and other materials; ln this application and others an added advantage ls the masking of obJectionable flavors or odors of the adsorbed materials. The resins may further be used in the treatment of acute polsoning, such as by heavy metals, drugs, and the endotoxins, exotoxlns, enterotoxins and the llke of micro-organisms. Other uses in the area of lnternal medicineinclude removal of pyrogens from materlals which would come into contact with the blood, removal of micro-organisms from the stomach and intestines, and use as an in~ectable contrast medium for radiography.
Further uses of the resins of this invention are in the area of externa] medicines and medical treatments. These lnclude use as pH control agents, for the treatment of contact dermatitis caused by poison ivy or other agents, as anti-perspirants, deodorants, and skin mlcrobiocldes, as antl-irritants either for this property alone or while also serving as a drug carrier, and in the treatment of bites or stings from insects, arachnids, snakes and the like.
Domestlc and industrial uses of the resins of this invention are in the areas of flocculation, filtration and deionization. Combinlng the strongly acidic resins in the hydrogen form with the strongly baslc resins in the hydroxyl form produces a floc which may be used as a flltration and deionization medium for condensate water, or as a flocculant and filtration aid for fermentation broths. The strongly basic or weakly basic resins may be used to remove free acids from 1 ~6~197 edible oils and for decolorizing crude sugars and molasses. The strongly basic and weakly baslc resins may be used to remove ~ulvic and hu~ic acids from potable water, and to bind and remove micro-organlsms 5 ~ from such water. The floc formed by combining weakly acidic and weakly basic resins may be used for deionization-of water, crude sugars and the like. The floc formed by combining strongly basic and strongly acidlc resins may be used for demineralization of process fluids, crude sugars, whey, and the like.
Further uses for the resins of this invention are as additives to paper and nonwoven textile ~aterials.
They may be incorporated into disposable diapers and sanltary napkins as deodorants and anti-bacterial agents. They also serve as dye acceptors for incorporation into paper, te~tiles and pain~s; in this application they may also be blended into polymers prior to fiber extrusion.
~urther uses for the resins of this in~vention are as formulating aids for agricultural products. They may serve as controlled-release substrates for biologically active materials, including pesticides, fertilizersa growth hormones, minerals and the like, as suspension aids for pesticide formulations and similar applications where their emulsifiability and ion exchange activity are desirable, and as pH control agents.
Still further uses for the resins of this invention are in the area of catalysis and scavenging. They may serve as high-surface-area, heterogeneous acid or base catalysts, for example, ln the conversion of cumene hydroperoxlde to phenol and ~ ~.6~g~

acetone, as an acld acceptor, ~or example, in the synthesis of ampicillin, and as a scavenger ~or products, by-products or metabolites to shift reaction equilibria toward completlon. They may serve as enzyme actlvators, for example, in fructose con~ersion, and as substrates for lmmobilizing enzymes. The dry resins may be used as desiccants for organic solvents.
Miscellaneous uses for the resins of thls invention include use of the weakly acidlc resins in synthetic detergents as sequestering agents and replacements for phosphate builders, use, especially of the weakly acidic resins in the potassium ~orm, as tablet dislntegrating agents; and use as extractants in hydrometallurgy, for the recovery of germanium, uranlum, zinc and the like. The small size of the resins allows their use in ultrafiltration applications within the lumens of fine hollow fibers. They may be used as ion exchangers or adsorbents for removing metals or metal porphyrlns ~rom petroleum residues.
They may be used as high-surface-area extractants for the purification of organic acids such as lactlc, citric, tartaric and similar acids produced by ~ermentation. They may be used to remove proteins and amino acids from the waste ~ater of sugar refineries, slaughter houses and the like, and the resulting loaded resins, because of their pleasant mouth feel and lack of taste, may be fed directly to domestic animals such as cattle.
Sugar decolorization and clarification using 3o emulsion ion exchange resins of the present lnvention offers significant advantages over conventional processes. Conventionally raw sugar solutions are . . ' i 1 IB~97 treated wlth regenerable adsorbents such as bone char, activated carbon, or conventlonal ion exchange resinsO These adsorbents requlre chemical regenerants or heat for regeneration, and produce undesirably dilute sugar solutions. In most refineries several decolorization operatlons follow the clarlfication operations, aften includlng a sulfur dioxide bleach, addition of non-recoverable powdered carbon, or use of a flocculating agent. The emulsion reslns of the present invention permit a slngle-step decolorization and clarificationO When added to lmpure sugar solutions they form coherent, filterable flocs with the charged particulate impurities usually present in such solutions. Although the resin particles are incorporated into the floc, they retain their ion exchange functionality, and therefore remove dissolved ionic impuritles and color-imparting impurities from the solutlons. They further remove particulate and color-imparting impuritles either by co-precipitation during the formation of the floc, or by retaining such impurities during filtration of the floc-containing solution. Yet another mechanism by which the flocs remove impurities from the solutions is adsorption onto the particles which comprise the flocs; being extremely small, these particles contribute high surface area to the flocs. By one or more of these mechanisms the emulsion ion exchange resins of this invention remove from the sugar solutions the impurlties which impart color and lack of clarity, and additionally salts and the precursors to the color impurlties. The flocs containing adsorbed and entrained impurities may be removed ~rom the sugar solutlon by ~iltration, ~, . .. . .
~ . , 1 ~119~

flotatlon or other known processes~ The sugars which may be treated include cane, corn, beet and other sugars. The excellent kinetics of khese emulsion resins, resulting from their flne particle size, allow them to act far more rapldly as ion exchangers than the conventlonal ion exchange resins heretofore employed, and the flocs -themselves have the added advantage of acting as a filker aidO The use of the emulslon resins of this lnvention for decolorlzing and clarlfying sugar solutions is illustrated in Example 27 below.
In those cases where lnsufflcient charged particulate impurities are present in the impure sugar solution to lncorporate all of the added emulsion resin into the floc, a separate flocculating agent may be added to the solution. Such flocculating agents include both ionic surface-active agents having a charge opposite that of the emulsion resin, nl~nionic surface-active agents and finely divided ion exchange materials having a charge opposite that of the emulsion resin. These ion exchange materlals may be ground conventional resins or emulsion reslns.
While the preferred emulsion resins for sugar decolorization and clarification are anion exchange emulsion resins and the strongly baslc anion exchange emulsion resins are most preferred, acidic, cation exchange emulsion resins may also be used to treat sugars, and especially to treat sucrose for the purpose of inverting it. Inversion, the process of hydrolyzing the 12-carbon sucrose to a mlxture of the 6-carbon sugars, glucose and fructose, occurs in the presence of certain enzymes or of hydrogen ions.
Strongly acidic emulslon cation exchange resins may be ~1 .
,f~ '.

l lg7 used to supply these hydrogen ions without introducing undesirable soluble anions into the sugar. Following inversion the cation exchange emulsion resln may be removed from the invert sugar solution with a conventional flocculating agent or by addition of an anion exchange emulslon resin such as a strongly baslc emulsion resln. When such an emulsion resin is used~
it tends to further clarlfy and decolorize the sugar solution, and the floc which forms acts as a filtratlon aid. The advantage of such a process over conventional treatment of sucrose solutions in a bed of catlon exchange resin beads is that a more concentrated, hence more viscous, solution may be treated with the emulsion resin than with the bead resins.
As noted above, combinlng a cationic emulsion copolymer resln with an anio~ic emulsion copolymer resin allows the oppositely charged particles of the two types of resins to interact and form a loose, electrostatically bound floc. The floc has excellent kinetic properties for lon exchange because liquids readily penetrate it, and because the lndivldual particles themselves are so small that they are readily penetrated. The floc is readily disrupted by shear forces, but because the electrostatic attraction of the oppositely charged particl~s remains, the floc re-forms when the shear force is removed. Because of thls the floc may be pumped by conventional, liquid-handling pumps as though lt were a liquid. It may also be supported on relatively coarse, low-pressure-drop filter screens where the electrostatic attraction mlnimlzes particle sloughage during use. In additlon to the deionlzation propertles, these flocs have : , J ~6~197 ~excellent filtration properties, as shown by Example 25 below The deionization and ~iltration properties of these flocs may be utilized simultaneously, as when ~removing ions and particulate matter from steam generator condensate water. In such an appllcation the floc is usually pre-coated onto the filter cloth, filter screen; filter leaf or other mechanical filter means. The floc may be pre-formed by mixing the cationic and anionic copolymer resin emulslons prior to transferring it to the filter ltself, or the floc may be prepared in the llquid to be treated and filtered by adding emulslons of the cationic and anionic emulsion copolymer resins to the liquid. In this latter case, entrainment of particulate matter within the floc as it forms may be an additional advantage. The flocs described hereln may be prepa~ed by mlxlng strongly acidic emulsion copolymer resins with strongly basic or weakly basic emulsion copolymer reslns and weakly acidic emulsion copolymer resins with strong~y baæic or weakly basic emulsion copolymer resins. They may be formed by mixing particles of one or more cationic emulsion resins with particles of one or more anionlc resins; weakly acidic and strongly acidlc emulsion resins may be mixed, as may weakly basic and strongly basic emulslon resins, and these mixtures may be used to form flocs. Emulsion reslns having different particle sizes may be mixed to form flocs, including a multiplicity of cationic emulsion resins having different sizes, or a multipllcity of anionic emulsion resins ha~ing different sizes; such mlxtures are used to control the texture, and hence the flltering and other handling characteristics, of the flocs. The I

"```i !

- 25a -; formation of flocs is illustrated ln Examples 22 and 23 below.
Flocs prepared ~rom weakly acidic and weakly basic emulsion reslns have the additional useful property of being thermally regenerable~ That is, the floc may be used to remove anions and cations from a relatlvely cold liquld,-and these anions and catlons may be replaced with hydrogen and hydroxyl ions from a relatively hot aqueous llquld during regeneration.
Such flocs differ from conventlonal thermallg regenerable reslns which are usually large, hard beads containing areas of both acidic and basic functionality. Because the thermally regenerable floc can ~orm a large, coherent mass, it may be used with mo~ing-bed deionization equipment. In such equlpment the floc is coated on a movlng filter support which continuously transports the floc through a deionization section, where it contacts the cold liquid being treated, and through a regeneration section, where it contacts a hot, aqueous regeneration liquid. It may similarly be used in continuous-deionization processes in which the floc is circulated by pumping through a deionization vessel and a regeneration vessel, the floc moving through the deionization vessel in a direction opposite to the flow of treated llquld. The thermal regenerability of the weak acid-weak base flow at two different pH values, and a comparison of its thermal capacity with that of a conventional thermally regenerable bead resln ls illustrated ln Example 24 below. -In the formation of flocs upon mixing cationlc andanlonic emulsion resin materials, a single particle !

t ~ B~ ~7 ~ 26 -establlshes an electrostatic attraction for more than one particle of opposlte chargeO Especially where larger partlcles of one charge, as for lnstance particles between about 0.7 and about 1.5 micrometers in diameter, are mixed with fine particles, as for lnstance those with diameters smaller than 0.1 micrometer, of the opposlte charge, many fine particles may cluster about the large particles. As a result the ratio of cationic emulsion resln to anlonlc emulsion resin in flocs may be varied over a wlde range by ad~usting particle slzes. Flocs may be prepared with the cationic resln to anionic resin ratio ranglng from about 9:1 to about 1:9. Even in the case of particles of opposite charges having approximately the same diameter the cationic resln to anionic resin ratio may be varied over at least the range from about 3:2 to about 2:3; this is a preferred range, regardless of diameter. A more preferred ratio of cationic resin to anionic resin is about 1:1.
The emulsion copolymer ion exchange reslns of this invention may be changed from one ionic form to another by contacting them with conventlonal ion exchange resins, that is, with ion exchange resins having particle si~es of about 40 micrometers or larger, and preferably those resins suited for use in conventional ion exchange beds. Particles of ion exchange resin havlng diameters of about 40 micrometers or greater are referred to hereln as "macrobeads", regardless of whether they are spherlcal beads or of other geometric shapes. For example, an emulsion anion exchange resin prepared in the chloride form may be changed to the hydroxyl form by passlng an emulslon of the resin .

~61~97 - 26a -through a conventional bed of strongly baslc anion exchange resin in the hydroxyl form. Chloride lons of the emulsion resin are exchanged for hydroxyl lons of the conventional large-bead resin as the emulsion resln passes through the column. Because the ions are exchanged by each resin, the lonic form of the conventional resin is also changed. This process may therefore be used to change the ionlc form of the ~ emulslon resin to a desired form, or to change the resins of fixed beds to a desired ionic form, as in ion exchange bed regeneration. Individual or mixed emulsion resins, and individual or mixed conventional resins, may be employed in this process. The emulsion resins are preferably of the same ion exchange type as the~conventional resins; "ion exchange type" as used herein meaning the lonic type of the lon exchange functional groups: either substantially catlonic (acidic) or substantlally anionic (basic).
Ion exchange will occur between such resins both ln a batch process, where the exchange is al:Lowed to reach equllibrium, and in a column or bed pr~Jcess, where continuous equilibration produces a high conversion to the deslred ionic form, ~ust as it does in conventional treatment of ionized solutlons wlth lon exchange beds. Thls process ls illustrated in Examples 8, 19 and 21, below.
The following examples are intended to lllustrate, and not to limit, the invention. All percentages used herein are by weight unless otherwise specifled, and all reagents are of good commerclal quality.
Example 1 This example illustrates the preparation of a ... :', 116î3197 styrene divinylbenzene emulsion copolymer. A monomer emulsion is prepared by stirrlng vieorously under a nitrogen atmosphere 370 g of deoxygenated water, 48.2 g o~ Triton X-200 (trademark of Rohm and Haas Company~
Phlladelphia, Pennsylvaniag for the sodium salt of an alkyl aryl pol~ether sulfonate surface-active agent containing 28% solids), 348.8 g of styrene and 51.2 g of commercial-grade divinylbenzene (54.7%
divinylbenzene, balance essentially ethylvinylbenzene). An aqueous initiator solution is prepared by dissolving 2.0 g of potassium persulfate in 100 g of deoxygenated water, and 50 g of the monomer solution is added to the initiator solution. The mixture is stirred to develop a l-inch vortex and is heated to 70C under the nitrogen atmosphere. When polymerization begins, as evidenced by a sudden decrease in opaGity, the remaining monomer emulsion is added over a period of 1.5 houræ. The temperature is held at 70C for one hour after the addition is completed. The polymer emulsion is cooled tc room temperature and filtered through cheesecloth. The measured solids content of the emulsion is 43.0%, - versus a calculated value of 45%.
Example 2 This example illustrates the brine coagulation of the polymer emulsion prepared in Example 1~ A 1400-ml quantity of 25% aqueous sodium chloride solution is heated to 100C. While stirring the solution, 700 ml of the emulsion prepared in Example 1 are added at as rapid a rate as is possible without the solution temperature falling below 95C. The solution temperature is held at 100-103C for 30 minutes, and !

- 27a -the solid coa~ulum ls filtered out on a USA Standard Series 150~m (alternative designation No. 100) sieve. The coagulum is rinsed wlth water and drled overnight at 100C~ the yield after drying is 292.1 g.
Example 3 This example illustrates the sulfuric acld coagulation of the polymer emulsion prepared in Example 1~ To 250 ml of stirred, concentrated sulfuric acid, 41 ml of the polymer emulsion of Example 1 are added through a Pasteur pipette with its tip beneath the sur~ace of the acid. The resulting vermiform coagulum is about 1.5 mm in dlameter and 5-7 mm long.
Example 4 This example illustrates the sulfonation of the coagulum of Example 2 to form a strongly acidic catlon exchange materlal. A 20-g ~uantity of the dry coagulum from Example 2 is mixed with 120 ml of concentrated sulfuric acid and heated under nitrogen atmosphere with stirring to 120C; it is held at this temperature for 5 hours. The reaction mixture is allowed tc cool, and water is added as rapidly as possible without allowing the temperature to rise above 95C. The solid material is allowed to settle, and the supernatant liquid is removed. About 120 ml of water are added to the solid material and then removed~ The solid material is transferred to a filter tube, rlnsed with water and drained; the yield is 103.8 g of material with 31.7%
solids. The cation exchange capaclty of this material is 5.22 milliequlvalents per gram of the material in dry, H+ form, compared with 5.26 meq/g theoretical.
It should be noted that theoretical ion exchange capaclty and theoretical degree of functionallzation, , - I

~; ' t ~ 61~97 as used herein, is based upon the assumptlon of one functional group per aromatic ring (styrene reslns) or per monomer unit (acrylic resins). Since this value may be exceeded under certain conditions, measured values greater than "theoretical" may occur Example 5 This example illustrates the chloromethylation and aminolysls of the coagulum from Example 2. A 20-g sample of the dry coagulum from Example 2 is 3welled ln a mixture of 17 ml of chloromethyl methyl ether and 69 ml o~ propylene dichloride. While stirring ~his slurry a solution of 19 g of alumlnum chlorlde in 25 ml of chloromethyl methyl ether is added slowly with cooling, keeping the temperature at 32C or less throughout the additlon. The reaction mixture ls held at 32C ~or 2 hours and then ~s cooled to 15C'C. Water is added dropwise with cooling, keeping the temperature to 30C or less. The aqueous layer is decanted from the swollen organic layer and the product is washed twice with water, once with 4% aqueous sodium hydroxide solution, and once again with water. The solid product is filtered; its weight while still wet with propylene chloride is 105 g. A 15-g sample of this chloromethylated intermediate is slurried with water containing 40 mg of 1200-molecular-weight poly(ethyleneimine). The mixture is heated and the propylene chloride stripped out. The mlxture ls cooled and 9 ml o~ 25% trimethylamine are added. The temperature o~ the mixture ls raised to 70C, held constant for 5 hours, and raised to 95C to strip out the excess trimethylamine. The resulting solid is transferred to a fllter tube, rinsed with water and ,, ~ 1 611~

- 28a -dralned; the yleld is 14.6 g o~ mater1al with a sol1ds , X

1 1 6~97 , - 29 -content of 35.9%. The anion exchange capacity of this material is 3.~4 meq/g of dry material in the chloride form. Microanalysis ~hows it to have the following composition:
~ 67.16~
8~49%
O 6.~2%
N 4.82%
Cl 12.37%
(correc~e~ for = ~2~) N = 3.7 meq/g.
Cl = 3.8 meq/g.
Example 6 This example illustrates the aminolysis of a vinylbenzyl chloride-divinylbenzene emulsion copolymer coagulum. An emulsion copolymer of vinylbenzyl chloride and divinylbenzene (commercial grade, containi,ng 54.7%
divinylbenzene and the balance essentially ethylvinylbenzene) is prepared according to the procedure of Example 15 below; ~he copolymer contains 8%
~ divinylbenzene and has a measured solids content of `' 29.6%. The emulsion copolymer is allowed to stand'until it coagulates, and 50 9 of the coagulum are s3urried with a solution of 0.15 g of 1200-molecular weight poly(ethyleneimine) in 100 ml of wa~er. The slurry is heated to 60C, held a~ that ~emperature for one hour, ,~ and transferred to a pressure reactor. To the reactor 40 g of 40% dimethylamine and 5.4 g of 50% aqueous sodium hydroxide solution are added. The mix~ure is stirred and heated to 60C, held a~ that temperature for one hour, then heated to 87C and held at that temperature for 4 hours. T~he reactor is cooled and purged with nitrogen, and the reaction mixture is filtered. The solids are rinsed with water and drained; microanalysis of a small, dried sample of the solids shows the following ` :

values:
C81.59%
H9.00%
02.52%
N6~57%
(results are corrected for 0 = H20).
N = 4.8 meq/g, as compared to a theoretical value of 5.3 meq/g-Example 7 This example lllustrates the preparation of a methyl acrylate-divinylbenzene emulsion copo]ymer. A
dispersion of 24 g of Triton X-200 in 360 g of deoxygenated water is prepared under a nitrogen atmosphere in a l-liter, round-bottomed f`lask9 and is stirred to create a l-inch vortex. A mixture of 29 g of di~inylbenzene (commercial grade containing 55.2%
dlvinylbenzene and the balance essentially ethylvinylbenzene) and 171 g of methylacrylate is added to the aqueous dispersion, followed by 4 ml c,f freshly 20 prepared, 820 ppm ferrous sulfate solutlon and 50 ml of deoxygenated water containing 1.0 g of ammonium persulfate solution. This mixture is stlrred for about 15 minutes and cooled to 20C. A solution of 1.0 g of sodium metabisulfite in 20 ml of water and 5 drops of ~5 70% t-butyl hydroperoxide are added to the mixture.
After a 5-minute induction period the temperature is observed to rise to 80C during a period of 6 minutes, and thereafter to fall slowly. After 30 minutes, the mixture is cooled to room temperature and filtered through cheesecloth. The solids content of the filtered emulsion is determined to be 31.0%, as compared to a theoretical value of 31.4%.
!

J `,~.

Example 8 This example illustrate8 the hydrolysls and resuspension of ~he methylacrylate-dlvinylbenzene copolymer of Example 7 to produce a weak-acid-functionalized ion exchange resin emulsion. A 200-g sample of the emulsion produced in Example 7 ls added to a stirred solution of 57.4 g of 50% aqueous sodium hydroxide solution in 250 ml Or water -- this represents a 20% excess of base -- and the emulsion is observed to coagulate. This mixture is heated to 93C, held at that temperature for 2 hours, and cooled to room temperature. The coagulum is observed 1;o re-suspend in the sodium hydroxide solution dur'lng the stlrring and heating period. The emulsion product is diluted to 800-850 ml with water and is passed through a column of "Amberlite IR-120" cation exchan~,e resin (trademark of Rohm and Haas Company, Philadelphia, Pennsylvania~ for a sulfonic acid functionalized, styrene/divinylbenzene gel cation exchange bead resin) in the H+ form to remove the excess sodium hydroxide and convert the product to the free acid form. The solids content of the resulting emulsion is 4.74%, and the weak acid cation exchange capacity is 9.4 meq/g of dry polymer.
Example 9 This example illustrates resuspension of the functionalized emulsion copolymer coagula prepared in precedlng examples. The functionallzed coagulum is transferred to a high-speed blender container tmlnibottle assembly of a "Waring Blendor"*, *Trademark 1~61~97 model 7011-31 BL 41) and ~ust covered with water. The blender is operated at hlgh or low speed ~or one-hal~
minute to twenty mlnutes, as required to re-suspend the emulslon.
Example 10 This example lllustrate~ the aminolysls and resuspension ~r the emul~ion copolymer coagulum prepared as des ribed ln Example 6. A 1 7-e sample of the coagulum i8 slurried ln 125 ml of water and 9.0 g of~anhydrous trlmethylamlne are added. The temperature is observed to rise to 33C, the slurry ls further heated to 65C, and the excess trimethylamine ls swept off with a nltrogen gas stream. The resulting product, although Yery thick, is fully suspended. The solids content of the emulsion is 16.3%.
Example 11 The particle-slze distributlon of a sample of the OH form of a strongly baslc, emulslon copolymer ion exchange resin9 prepared a~ described in Examples 1~ 2 and 5 by amlnatlng a chloromethylated styrene-7%
divlnylbenzene emulslon copolymer wlth trimethylamine, ls measured ~y electron photomicrography. The mean particle dlameter i8 147 nanometerq (1 mlcrometer =
1000 nanometers) 9 approximately 76% of the partlcle diameters ~all wlthin a 18-nanometer range, and approximately 95% of the particle dlameters fall within a 33-nanometer range.
Example 12 The partlcle size dlstrlbutlon of a sample of weakly acldic, carboxyllc acld functionalized, acrylate emulslon copolymer lon exchange resin containing 8%
divlnylbenzene9 in the H form, prepared as described . i ~ .

... . . . .. .. . . ... . . . . . . .. .

~ 18~19~

~ 33 -in Examples 7 and 8, is measured by electron photomicrography. The mean particle dlameter ls 48 nanometers, approximately 84% of the particle diameters fall within a 19-nanometer range, and approximately 95% o~ the particle diameters fall within a 29-nanometer range.
Example 13 This example illustrates the preparation of a styrene-divlnylbenzene emulsion copolymer having a particle slze larger than 0.5~ m by a process whlch involves adding the monomer solution to a pre-formed copolymer emulsion for polymerization~ A monomer emulsion is prepared by stirring vigorously under a nitrogen atmosphere 180 g of deoxygenated water, 14.3 g f Triton X-200 377~8 g of styrene 22.2 g of divlnylbenzene (54% divinylbçnzene, balance largely ethylvinylbenzene) and 0.8 g of ammonium persulfate.
Under a nitrogen atmosphere in a separate container 348 g of deoxygenated water is stirred to develop a l-inch vortex and is heated to 95C. To this 13 g of a previously prepared emulsion copolymer is adcled, followed by 1.2 g of ammonium persulfate. (The previously prepared emulsion,copolymer is a 3%
divinylbenzene-styrene emulsion copolymer containing 43.3% solids, previously prepared according to the method of Example 1 and having a particle size of approximately O.l~m.) The mixture is stirred for 30 seconds and the monomer emulsion prepared above is added dropwise during a 3.5-hour period; the temperature is maintained at about 90C. When the addition is complete the temperature is maintained at 90C for 30 minutes, after which 33.7 g of TRITON X-200 . . .
;

is added. The emulsion ls cooled to room temperature and filtered through cheesecloth. The measured sollds content is 36.5% versus a calculated value of 42.4%.
Example 14 This example illustrates the preparatlon of a styrene~divinylbenzene emulsion copolymer of fine particle size; A monomer emulsion is prepared by stlrring vigorously under a nitrogen atmosphere 90 g of deoxygenated water, 2.73 g of Slponate DS-4 (trademark of Alcolac, Inc. for the sodium salt of dodecylbenzene sulfonic acid), 123.5 g of styrene, 72.5 g of divinylbenzene (55.2% dlvinylbenzene, balance largely ethylvinylbenzene~ and 4.0 g of glacial methacrylic acld. Under a nitrogen atmosphere in a separate container 350 g of water, 33.09 g of Siponate DS-4, and 1.0 g of potassium persulfate~are stirred and heated to 850C. The above monomer emulslon is added dropwise during a 3.5~hour period while the temperature is maintained at 850C. A solution of 0.4 g of potassium persulfate in 75 ml of water ls added and the mixture is stirred at 85C for 2 hours. The product is cooled to room temperature and flltered through cheesecloth.
The measured solIds content is 26.0% versus a calculated value of 27.0%.
Example 15 This example illustrates the preparation of vinylbenzyl chloride-divinylbenzene emulsion copolymer. A mixture of 1~0 g of potassium persulfate, 35.74 g of Siponate DS-4 and 350 g of deoxygenated water are stirred under a nitrogen atmosphere. A
mixture of 171 g of vinylbenzyl chloride and 29 g of divinylbenzene (55.2~ divlnylbenzene, balance largely ` !

,~ I

~ ~ 61 19~

ethylvinylbenzene) are added. This m~xture ls cooled to 0-10C and swept with nitrogen for 2 hours. A
solution of 1.0 g of potassium persulfate in 50 g Or water is added and khe temperature ls raised to 30C
for 18 hours. A solutlon of 0.48 g of sodium bicarbonate in 20 g of water is added and the temperatu~e is raised to 400C for 6-24 hours. The product is cooled to room temperature and is filtered through cheesecloth. The measured solids content ls 29.6% versus a calculated value of 31.8%.
Example 16 This example illustrates the brine coagulation of the polymer emulsion prepared ln Example 7. A 40 g sa~ple of polymer emulsion prepared in Example 7 is added to lOO ml of a stirred solution of 25% sodium chloride in water at 100C. ,The temperature is maintained for 2 mlnutes and cooled to 50C. The solid product ls filtered and rinsed with water followed by methanol. The solids content of the water-rinsed coagulum is 50%.
Example 17 This example illustrates the chloromethylation and aminolysis of the copolymer emulsion prepared in Example 13. A sample of the copolymer emulslon prepared in Example 13 was coagulated and dried according to the method of Example 2. A 44.4 g sample of dry coagulum ls swelled in 403 ml of propylene dichloride at room temperature for 1.5 hours. The slurry is stirred and 80.5 ml of chloromethyl methyl ether is added. The mixture ls cooled to 10C and a solution of 34.5 g of aluminum chloride in 42 ml of chloromethyl methyl ether is added dropwise over 20 ~'~
... .

- 35a -minutes while the temperature is maintained at 10C.
The stlrred mixture is held at 10C for 4 hours; it is subsequently added to 350 ml of water with sufflcient cooling that the temperature never rises above 30C.
The reaction mixture is diluted with 250 ml of water, stirred for 30 minutes and the phases are permitted to separate. The aqueous phase is decanted and the organic layer is batch washed three tlmes with water, once with 4% sodium hydroxide solution, and twice more with water. Approxlmately 25% of this product, 80 ml of 25% aqueous trimethylamine, 3 g of 50% sodium hydroxide solution and 120 ml of water are co~blned and heated to 65C durlng a 3-hour period. The temperature ls then raised to about 75C and the propylene dichloride-water azeotrope ls stripped out. The material is cooled to 50C and nitrogen is s~ept across the surface of the stirred product to remove excess trimethylamine. The polymer emulsion product is allowed to stand overnight and is decanted from any small residue of settled solid The solids content of the product is 17%.
Example 18 This example illustrates the aminolysis of a chloromethylated styrene-divinylbenzene copolymer coagulum prepared as described in Example 5. A 20 g sample of a 7% divinylbenzene-styrene copolymer coagulum ~. ~

1 3Bll9~

prepared according to Example 2 is chloromethylated according to the procedure of ~xample 5. Approximately ~0~ of the propylene dichloride-swollen product, lO0 ml of water, and 25 ml of 25% aqueous trimethylamine are stirred at room temperature for the two hours and h~ated to 65C for five hours. The temperature is raised ~o 85C and the propylene dichloride and excess trim~thylamine are stripped out. The aminolyzed product is a solid which is filtered and rinsed with water.
Example 19 This example illustrates the conversion of a hydrolyzed and resuspended methyl acrylate-divinylbenzene emulsion copolymer from the salt form to the free acid form by batch treatment with a strong-acid ion exchange lS resin. A sample of 237.7 g (0.71 eq) of a methyl acrylate-divinylbenzene copolymer emulsion prepared according to Example 7 is hydrolyæed with 250 g of 12.5%
sodium hydroxide solution according to the procedure of Example 8. The resulting thick, homogeneous product is slurried with 500 ml (0.9 eq) of Amberlite IR-120 ion exchange resin (product of the ~ohm and ~aas Company, Philadelphia, Pennsylvania) in the ~ form and rapidly becomes more fluid. The beads of Amberlite I~L-120 ion exchange resin are filtered and rinsed wi~h water; the combined filtrate and rinses weigh 672 9 (9.17% solids, 97~ of theory)~ Microanalysis shows the following results:
C-55.92%
~=6.18%
O=34.54%
Na=144 ppmO
Example ~0 This example illustrates the amination of the emulsion polymer coagulum prepared in Example 16.
sample of the coagulum prepared in Example 16 is dried at .. , . .. ~ . . .... , . , .; , ~ 16~197 110C and 4 g of the dry solid is heated with 15 g of bis(3-dimethylaminopropyl)amine to 230C ~or two hours. The methanol produced is swept away with a stream of nitrogen. The reaction mixture is diluted with methanol and the coagulum is filtered, rinsed wlth methanol and with water~ and drained. The solids ~content Or the aminated product is 40% versus 50% for the water-rinsed starting material.
Example 21 This example illustrates the ion exchange and conversion of a strong-base-functionalized copolymer emulsion prepared according to Example 17 from the chloride form to the hydroxide form by means of column treatment with Amberlite IR-120 and Amberlite IRA-400 ion exchange resins (products of Rohm and Haas Company, Philadelphia, Pa.), in the hydrogen and hydroxyl forms respectively. A 5 ml sample ~f a strong-base-functionalized copolymer emulsion prepared according to Example 17 is passed through a column of 8.55 ml of Amberlite IR-120 ion exchange resin in the Hl at a rate of 0.5 bed volumes per hour; it is washed through the column with deionized water. The effluent is then passed through a column of 7.6 ml of Amberlite IRA~400 ion exchange resin in the OH at 0.5 bed volumes per hour and is similarly washed through the column with deionized water. A total of 13.1 ml of effluent is collected. A 4 ml sample of this effluent is titrated to a pH = 7 endpoint with 4.35 ml of 0.1 N hydrochloric acid. A 0.5 g sample of effluent and .56 ml of 0.1 N
hydrochloric acid are evaporated to dryness, yielding 0.164 g of a solid material; 2.99% solids in the hydroxyl form is calculated. A titrable strong base , ~r 1 1 6 1 ~7 -- 38 ~
capacity of 3.64 meq/g is calculated.
Example 22 This example illustrates the preparation of a floc ` from a strong-acid-functionalized copolymer emulslon and a strong-base-functionalized copolymer emulsion. A
sample of ll ml of a 0.5%-sollds suspension of a strong-base-f~nctionalized copolymer emulsion in the hydroxide ~orm, prepared according to Example 5, column treated with sodium hydroxide and resuspended as ln Example 9, and a sample of 9 ml of a 0.5%-solids strong-acid-functionalized copolymer emulsion prepared according to Example 4 and resuspended as in Example 9 are combined and shaken. The result is a solid floc which settles, leaving a clear, supernatant liquid.
Exam~e 23 This example illustrates.the preparation of a floc from a weak-acid-functionalized copolymer emulsion and a weak-base-functionalized copolymer emulsion. A
sample of 5 ml of a 2~07% solids, weak-acid-functionalized copolymer emulsion prepared according to Example 8 and a sample of 2.5 ml of a 3.97% solids, weak-base-functionalized copolymer emulsion prepared according to Example 6 are combined and shaken.
Deionized water is added and the product is a solid floc which settles, leaving a hazy supernatant liquid.
Example 24 This example illustrates the thermal regenerability of the floc produced by combining weak acid and weak base emulsion resins. A floc is prepared according to Example 23, the quantity of weak base and weak acid resin emulsions being selected to yield 0 7 2 g of floc. This floc is transferred to 16 ml of water, , ,~: ~
; ~

~ 3 Bl 1 97 and the pH is adJusted to 5.6 by addltion of ~ilute acid or base, as required, with rapid mixlng. Sodium chloride is added to the mixture until its concentration in the liquid phase is approximately 100 ppm, and the mixture is allowed to equilibrate at room temperature. The specific resistance is determined to-be 7200 ohm-cm, equivalent to 70 ppm sodium chloride. The mixture is heated to 92C while stirring, and is allowed to equilibrate at that temperature. Stirrlng is stopped, the floc is allowed to settle while the temperature is maintained, and a portion of the supernatant liquid is transferred to a conductlvity cell. This sample is allowed to cool to room temperature, and its specific Fesistance is determined to be 4900 ohm-cm, equivalent to 102 ppm sodium chloride. The sample of supernatant liquld is returned to the total mixture, which is then cooled to room temperature. The pH and specific resistance are measured again, and are ~ound to be equal to the initial, room temperature values.
This procedure is repeated using a second sample of the same floc, and again using a typical, thermally regenerable, hybrid ion exchange resin, the preparation of which is described in U.S. Patent 3,991,017. The 25 measurement results for these materials are shown in the following table:

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This example illustrates the use of a strong acid~strong base floc for filtration of a finely divided, suspended material from water. ~ floc is prepared according to Example 22, the quantity of strong base and strong acid resin emulsions being selected to yield 79.5 mg of floc containing 47% cation resin and 53% anion resin. This floc is transferred to a 1/2-inch (1.3 cm) diameter ~lass tube containing a 100-mesh nylon screen.
A room-temperature suspension of 300 ~pb hematite (yellow iron oxides) in water is allowed to pa~s through the tube at a flow rate o~ 3.7 gpm/ft2 ~18 ml/minute ab~olute flow rate), at an inlet pressure of 25 psi (1.70 atmospheres). The pressure drop across the bed of floc and the Silting Inde~ of the ef~luent are monitored with time. The determination is stopped after 630 minutes, when ~he pressure drop approaches the 25-psi inlet pressure, although the floc is still filtering acceptably, as indicated by the 5ilting Index. The results of this determination are shown in Table II below.
The Silting Index is a number determined using the Millipore Silting Index Apparatus (~illipore Catalogue No. XX6801300), and is based on the times required to deliver pre-determined volumes of liquid through a 0.45-micron Millipore filter. Silting Index is described in Federal Test ~ethod 5350.

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TABLE II
Time, Minutes Pressure DroP, psl Siltinq Index 2 0.7 0.7 0.9 1.53 1.0 5~ 1.2 1.2 106 1.3 l.fi8 160 1.4 0.81 208 1.5 ` 1.00 ~55 1.7 1.17 310 1.8 1.76 350 2.0 2.09 400 4.4 3.19 44~ 7.8 2.15 490 13.4 2.45 540 19.2 2.47 5~0 - 2~.1 2.24 630 24.7 2.~0 Example 26 This example illus~rates the use of the strong acid-strong base floc for deionization. ~ floc was prepared according to Example 22, the ~uantities of strong base and strong acid resin emulsion being selected to yield 200 mg of floc containing 40% cation and 60~
anion emulsion resin. This floc was transferred to a 1/2-inch (1.3 cm) diameter glass tube containing a 100-mesh nylon screen. A solution containing 9.76 ppm NaC1 calculated as CaCO3 was allowed to pass downward `~ through ~he tube at a flow rate of 3.7 gpm/~ (18 ml/minu~e absolute flow rate) at roo~ temperature, at an inlet pressure of 25 psi (1.70 atmosphere). The pressure ~ 1 61197 . - 43 -drop across the bed and the specific resisthnce of the effluent are monitored. Breakthrough is defined as the point at which the effluent resistivity declines to 4.D
megohm-cm (approximately 10% leakage). This breakthroUgh occurs at about 23.5 minutes, and is equivalent to a calculated capaci~y of 0.048 g Cl /g dry anion re~in.
The results of this de~ermination are tabulated in Table III below:
A~LE IIT
Specific Resistance Time, MinutesPressure Drop, psimegohm-cm 1 0 6.20

3 ~ 7.60 6 0 8.4C
0 d.40 0 8.2 0 6.00 0 3.10 0 1.60 . 20 40 ~ 0.60 S0 0 0.275 0 0.140 0 O.G94 Example 27 This example illustrates th~ decolorization of a washed, raw sugar solution using emulsion ion exchange resins. A 125 ml sample of washed, raw sugar solution, typical of that received at refineries, and having an ICUMSA color of ~00 and a concentration of 65 Brix is ~ 30 heated to 80~C. To his is added 0.20 g, dry basis `~ (equivalent to 2000 parts resin per million parts sugar solids), of s~rongly basic anion exchange resin emulsion in the chloride form, made from the emulsion copolymer of 1 31611g7 ~ 4~ -Example 1, coagulated according to Example 2, chlorinated and aminolyzed according to Example 17. The mixture is stirred for five ~inutes, and is then transferred to a pressure filter where it is filtered through diatomaceous earth supported on coarse filter paper. The sugar solution filt~rs rapidly, and the filtrate is a clarified, decolorized solution with an ICUMSA color of lS0.
~he ICUMSA color determinatio~ ~y Revisea ICUMSA
Method 4 is described in the Cane Su~ar ~and~ook~ 10th Edition, published by John Wiley and Sons. This color determination is made at a wave length of 420 n~nometers and a measured pH of 7.0, and the result is e~trapolated to a sugar concentration of 100%.
~
This exam~le illustrates the suspension in an ; organic solvent of a floc prepared from cation and anion emulsion resins. A 9-ml sample of strongly acidic emulsion cation exchange resin, prepared according to ~; 20 Example 4 and resuspended as a 0.5% solids e~,ulsion according to Example 9 is mixed ~ith an ll-ml sample of strongly basic emulsion anion exchange resin, prepared according to Example 18, rinsed as a coagulum with 4%
a~ueous sodium hydroxide solution to correct it to ~he hydroxyl form and resuspended as a 4.5% solids emulsion according to Example 9, ~o form a floc. ~he floc is transferred to a sintered glass filter funnel, allowed to drain, and rinsed with acetone to replace the water from the floc. ~he floc is observed to retain its flocculant character in the non-aqueous, acetone medium. The floc ~ is subse~uently dried, first in a stream of nitrogen and '~ finally in an oven a~ 95C. The dried floc is ;. photographed u~ing a scanning electron microscope, and is : observed to h~ve a microporous ~tructure, that is, `~ : 35 relatively large void ~paces exist ~ithin the structure ` o~ cohered, emulsion resin beads.

- . .~ . . . .

Claims (22)

1. Novel, submicroscopic anion exchange resin particles comprising approximately spherical beads of crosslinked copolymer having diameters within the range from about 0.01 to about 1.5 micrometers, and bearing from about 0.7 to about 1.5 anion exchange functional groups per monomer unit.

2. The anion exchange resin particles of Claim 1 wherein the copolymer is an aromatic copolymer.

3. The anion exchange resin particles of Claim 2 wherein the aromatic copolymer is a styrene copolymer.

4. The anion exchange resin particles of Claim 3 wherein the styrene copolymer is a copolymer of styrene and divinylbenzene.

5. The anion exchange resin particles of Claim 1 wherein the copolymer is an acrylic copolymer.

6. The anion exchange resin particles of Claim 5 wherein the acrylic copolymer is a copolymer of divinylbenzene and an acrylic monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate.

7. The anion exchange resin particles of Claim 1 wherein the anion exchange groups are strongly basic groups.

8. The anion exchange resin particles of Claim 1 wherein the anion exchange groups are weakly basic groups.

9. The anion exchange resin particles of Claim 1 wherein the diameters are within the range from about 0.01 to about 0.5 micrometers.

10. An aqueous anion exchange emulsion comprising water and suspended therein the anion exchange resin particles of Claim 1.

11. The anion exchange emulsion of Claim 10 wherein the copolymer is an aromatic copolymer.

12. The anion exchange emulsion of Claim 11 wherein the aromatic copolymer is a styrene copolymer.
15.

13. The anion exchange emulsion of Claim 12 wherein the styrene copolymer is a copolymer is styrene and divinylbenzene.

14. The anion exchange emulsion of Claim 10 wherein the copolymer is an acrylic copolymer.

15. The anion exchange emulsion of Claim 14 wherein the acrylic copolymer is a copolymer of divinylbenzene and an acrylic monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate.

16. The anion exchange emulsion of Claim 10 wherein the anion exchange functional groups are strongly basic groups.

17. The anion exchange emulsion of Claim 10 wherein the anion exchange groups are weakly basic groups.

18. The anion exchange emulsion of Claim 10 wherein the diameters are within the range from about 0.01 to about 0.5 micrometers.

19. A process for preparing novel, submicroscopic anion exchange resin particles comprising spherical beads of crosslinked copolymer having diameters within the range about 0.01 to about 1.5 micrometers and bearing from about 0.7 to about 1.5 anion exchange functional groups per monomer unit, which process comprises the steps of a) emulsion polymerizing a mixture of a major amount of a monoethylenically unsaturated monomer and a minor amount of a polyethylenically unsaturated monomer to form an emulsion of crosslinked copolymer beads, b) coagulating the emulsion to form coagulum particles of the copolymer beads, c) separating the coagulum particles from the emulsion polymerization medium, and d) functionalizing the copolymer beads with anion exchange functional groups.

20. The process according to Claim 19 wherein the copolymer beads re-disperse during functionalization to form an emulsion of functionalized beads.

21. The process according to Claim 19 wherein the copolymer beads remain as coagulum particles during functionalization, and the copolymer beads are re-dispersed subsequent to functionalization, to form an emulsion of functionalized beads.

22. A method for the removal of anionic impurities from a liquid containing such impurities which comprises contacting the liquid with an emulsion of submicroscopic, approximately spherical beads of crosslinked copolymer having diameters within the range of from about 0.01 to about 1.5 micrometers, and bearing from about 0.7 to about 1.5 anion exchange functional groups per monomer unit.