High crush strength heterogeneous ion exchange resins of crosslinked polymers having vinyl halide monomer polymerized therein

Ion exchange resins exhibiting increased crush strength and/or higher density are prepared from a cross-linked polymer by imbibing a halo-substituted olefin within the cross-linked polymer's structure and subsequently polymerizing the imbibed olefin. For example, imbibing vinylidene chloride within a chloromethylated, cross-linked copolymer of styrene and subsequently polymerizing the vinylidene chloride forms a high density resin, which resin is useful in the preparation of ion exchange and chelate type resins having improved crush strength.

BACKGROUND OF THE INVENTION 
This invention relates to heterogeneous ion exchange resins of a 
cross-linked polymer and a halo-substituted olefin. 
Ion exchange resins are normally solid materials which generally carry 
exchangeable ions. Due to their ability to exchange ions in a liquid 
without substantial alteration of the solid resin's structure, they are 
widely employed in recovery processes such as the recovery of uranium and 
in waste treatment to remove undesirable components from water. 
Generally, effective ion exchange resins are substantially insoluble but 
swellable to a limited degree in water and are resistant to physical 
deterioration such as excessive spalling and shattering. Moreover, in many 
applications, particularly up-flow column operations, often encountered in 
uranium recovery and sugar processing, the resin advantageously has a 
sufficiently high density to assure efficient removal of the valuable 
ionic ingredients from the ion containing liquid, which is generally a 
thick slurry, without entrainment loss of the resin. 
Conventionally, ion exchange resins are prepared by (1) haloalkylating a 
copolymer of a monovinylidene aromatic such as styrene and a cross-linking 
agent which is generally a polyvinylidene aromatic such as divinylbenzene 
in the presence of a Friedel-Crafts catalyst and (2) attaching ion active 
exchange groups to the halogenated product. For example, an anion exchange 
resin is prepared by aminating the haloalkylated polymer. See, Ion 
Exchange by F. Helfferich, published in 1962 by McGraw-Hill Book Company, 
New York. Unfortunately, these anion exchange resins, without 
modification, possess relatively low densities. 
Ion exchange resins having increased density are known in the art. For 
example, U.S. Pat. Nos. 2,769,788 and 2,809,943 disclose higher density 
ion exchange resins prepared by incorporating inert, finely divided solid 
materials of a high density, i.e., 2.5 g/cc or higher, into copolymer 
beads of the monovinylidene and polyvinylidene aromatic compounds. 
Unfortunately, these ion exchange resin beads exhibit excessive spalling 
and surface irregularities. Moreover, such beads have a low mechanical 
stability and have a tendency to break and spall when employed in a 
continuous operation. 
To increase the mechanical stability of high density ion exchange resin 
beads, German Patent Application No. 2,218,126 teaches higher density 
resins can be prepared by using a nonionic substituted styrene, such as 
monochlorostyrene, as the monovinylidene aromatic compound. Unfortunately, 
halogenated non-ionic substituted styrenes are relatively expensive and of 
limited availability. 
In view of the stated deficiencies of the known ion exchange resins having 
increased density and the methods for their preparation, it remains highly 
desirable to provide an improved heavy density ion exchange resin. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention is a heterogeneous ion exchange resin of 
(1) a cross-linked polymer having a plurality of active ion exchange 
groups pendant thereto and (2) an amount of a polymerized halo-substituted 
olefinic monomer (hereinafter referred to as a halo-olefin) sufficient to 
increase the density and/or improve the crush strength of the resin. 
In another aspect, the present invention is a method for preparing a 
heterogeneous ion exchange resin. In said method, a cross-linked polymer 
imbibes an amount of a halo-olefin sufficient to increase the density 
and/or improve the crush strength of the heterogeneous ion exchange resin. 
The imbibed halo-olefin is subsequently polymerized within the 
cross-linked polymer. Either before or after the imbibition of the 
halo-olefin, active ion exchange groups are attached as pendant groups to 
the cross-linked polymer. 
Surprisingly, the novel ion exchange resins of the present invention 
exhibit increased density and/or improved crush strength without a 
substantial reduction in their subsequent ion exchange activity. As such, 
gel or macroporous anion exchange resins, chelate type resins or weak acid 
resins having excellent capacities and an increased density or improved 
crush strength are provided. 
Among numerous other uses, the heterogeneous ion exchange resins of this 
invention are useful for removing electrolytes from water and other 
liquids in such operations as desalting, demineralizing and other 
purification processes. The heterogeneous anion exchange resins exhibiting 
increased densities are particularly useful in the removal of uranium from 
solution and the removal of ash and acidity from sugar solutions. 
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In general, the heterogeneous ion exchange resins of the present invention 
are characterized as having a halo-olefin polymerized within a normally 
solid cross-linked polymer bearing pendant active ion exchange groups. By 
the term "polymerized within" it is meant that the polymerized halo-olefin 
is physically and/or chemically attached to the cros-linked polymer and is 
contained within the cross-linked polymer's structure. 
The distribution of the halo-olefinic polymer within the cross-linked 
polymer may vary. For example, the halo-olefinic polymer may be grafted to 
groups pendant to the polymer chain, and, as such, become chemically 
attached to the cross-linked polymer. When the halo-olefin is imbibed by a 
haloalkylated cross-linked polymer and subsequently polymerized therein, 
the resulting halo-olefinic polymer is believed to be so chemically 
attached to the cross-linked polymer. Alternatively, the halo-olefinic 
polymer, while not being chemically attached to the cross-linked polymer, 
may constitute one or more distinct regions within the heterogeneous 
resin, e.g., the heterogeneous resin may have one or more regions of the 
halo-olefinic polymer dispersed in a continuous region of the solid 
polymer. On the other hand, the halo-olefinic polymer may constitute an 
essentially continuous web-like region which fills the interstices of the 
cross-linked polymer. In many cases, combinations of the above-mentioned 
distribution or other distributions may be present in the heterogeneous 
resin. Unless otherwise provided herein, the distribution of the 
halo-olefinic polymer within the cross-linked polymer is not particularly 
critical to the invention. 
In general, the cross-linked polymers forming the resins of the present 
invention are the addition copolymerization product of a polymerizable 
monoethylenically unsaturated monomer and a cross-linking agent 
copolymerizable therewith; typically, a polyethylenically unsaturated 
monomer. 
Kinds of polymerizable monoethylenically unsaturated monomers, 
cross-linking agents, catalysts, polymerization media and methods for 
preparing the cross-linked addition copolymers as granules or in 
spheroidal bead form, of the gel or macroporous type, are well known in 
the art and reference is made thereto for the purposes of this invention. 
Illustrative of such are U.S. Pat. Nos. 2,960,480; 2,788,331; 2,642,417; 
2,614,099; 2,591,573 for conventional gel type materials and U.S. Pat. 
Nos. 3,637,535; 3,549,562 and 3,173,892 for the more porous materials, 
i.e., the so-called macroporous material, all of which are hereby 
incorporated by reference. Of the known polymerizable monoethylenically 
unsaturated compounds, the monovinylidene aromatics such as styrene; 
monoalkyl substituted styrenes, e.g., vinyl toluene and ethyl 
vinylbenzene; and vinylnaphthalene are preferred in this invention, with 
styrene and vinylnaphthalene being most preferred. Preferred cross-linking 
agents include the polyvinylidene aromatics such as divinylbenzene, 
divinyl toluene, divinyl, xylene, divinyl naphthalene, trivinyl benzene, 
divinyl diphenyl ether, divinyl diphenyl sulfone and isopropenyl 
vinylbenzene; ethylene glycol dimethacrylate and divinyl sulfide; with the 
polyvinylidene aromatics, especially divinylbenzene, being most preferred. 
For the purposes of this invention, the copolymer product of such 
monoethylenically unsaturated monomers and cross-linking agents will be 
herein referred to as a "non-treated cross-linked polymer", meaning no 
subsequent chemical alteration of the copolymer product has taken place. 
Although the non-treated cross-linked addition copolymer can be employed in 
the preparation of the heterogeneous resins of this invention to achieve 
density increase, improvements in crush strength are generally exhibited 
in the heterogeneous ion exchange resin when the addition copolymer is 
halomethylated (preferably, chloromethylated) prior to the imbibition and 
subsequent polymerization of the halo-olefin. This significant increase in 
crush strength is believed to be due to the grafting of the olefinic 
polymer to the halomethyl groups pendant to the cross-linked addition 
copolymer and to the increased cross-linkage (via methylene bridging) of 
the copolymer during the polymerization of the olefinic monomer. 
Halomethylation of the cross-linked addition copolymer and the 
halomethylation agents employed in such halomethylation are also well 
known in the art and reference is made thereto for the purposes of this 
invention. Illustrative of such are U.S. Pat. Nos. 2,642,417; 2,960,480; 
2,597,492; 2,597,493; 3,311,602 and 2,616,877 and Ion Exchange, by F. 
Helfferich, published in 1962 by McGraw-Hill Book Company, New York, all 
of which are hereby incorporated by reference. In general, the 
cross-linked addition copolymer is halomethylated by contacting the 
copolymer with a halomethylating agent and a Freidel-Crafts catalyst such 
as ferric chloride, zinc chloride or aluminum chloride. Of the known 
halomethylating agents the halomethylating agents such as bromomethyl 
methyl ether, chloromethyl methyl ether and a mixture of formaldehyde and 
hydrochloric acid are preferred, with chloromethyl methyl ether being 
especially preferred. 
Alternatively, the halomethylated cross-linked polymer can be prepared by 
polymerizing a cross-linking agent as hereinbefore described, with a 
polymerizable halomethylated monoethylenically unsaturated monomer, 
advantageously a halomethylated monovinylidene aromatic such as 
vinylbenzyl chloride. As an example of such polymer and its method of 
preparation, reference is made to U.S. Pat. No. 2,992,544 (which is hereby 
incorporated by reference) wherein an ar-(chloromethyl)-styrene and a 
polyvinyl aromatic hydrocarbon cross-linking agent are copolymerized to 
form a cross-linked chloromethylated polystyrene. 
The resins of the non-treated or halomethylated cross-linked polymers 
employed for the imbibition and polymerization of the halo-olefin are 
preferably of the gel type. 
Although generally less preferred than the aforementioned non-treated or 
halomethylated cross-linked polymer, cross-linked polymers having active 
ion exchange groups such as primary, secondary or tertiary amine; 
quaternary ammonium; or carboxyl groups can be employed herein. In 
general, those resins of a cross-linked polymer having active ion exchange 
groups in ionic form, e.g., quaternary ammonium groups, are preferably 
macroporous type resins, whereas resins of a cross-linked polymer having 
non-ionic active ion exchange groups, e.g., 1.degree., 2.degree. or 
3.degree. amine or carboxyl groups, are preferably gel type resins. 
Cross-linked addition copolymers bearing pendant 1.degree., 2.degree. or 
3.degree. amine groups, i.e., weak base resins, or cross-linked copolymers 
bearing pendant quaternary ammonium groups, i.e., strong base resins, are 
easily prepared from the halomethylated, cross-linked addition copolymers 
(as described hereinbefore) using conventional techniques well known in 
the art. Illustrative of such techniques are U.S. Pat. Nos. 2,632,000; 
2,616,877; 2,642,417; 2,632,001; 2,992,544 and Ion Exchange by F. 
Helfferich, published in 1962 by McGraw-Hill Book Company, New York; all 
of which are hereby incorporated by reference. Typically, a weak base ion 
exchange resin is prepared by contacting the halomethylated polymer with a 
suitable aminating agent; generally, ammonia or a primary or secondary 
amine. Representative primary and secondary amines include methylamine, 
ethylamine, butylamine, cyclohexylamine, dimethylamine, diethylamine and 
the like. Such method generally comprises heating with reflux a mixture of 
the polymer and at least a stoichiometric amount of ammonia or the amine 
to a temperature sufficient to react the ammonia or amine with the 
benzylic halogen atom. A dispersing agent such as water, ethanol or the 
like is optionally employed. Advantageously, temperatures between about 
25.degree. and 150.degree. C. are employed for the reaction and the 
reaction is generally complete in from 2 to 6 hours at reflux temperature. 
Strong base ion exchange resins are prepared in a similar manner using 
tertiary amines such as trimethylamine, dimethylisopropanolamine, 
ethyldimethylamine and the like as the aminating agent. 
In the preparation of resins of non-treated, haloalkylated or aminated 
cross-linked addition copolymers by the methods hereinbefore described, 
the amount of the cross-linking agent most advantageously employed is 
dependent on a variety of factors including the desired density increase 
or crush strength improvement and the monomers employed in preparing the 
cross-linked addition copolymer. In general, the amount of cross-linking 
agent advantageously employed in said cross-linked addition copolymers is 
from about 2 to about 12, preferably from about 4 to about 10, weight 
percent based on the weight of the monomers employed in the preparation of 
the cross-linked addition copolymer. Advantageously, in resins of a 
non-treated cross-linked addition copolymer, the cross-linking agent is 
advantageously employed at from about 1 to about 6, preferably from about 
2 to about 4, weight percent based on the weight of monomers employed in 
preparing the cross-linked polymer. Alternatively, in resins of a 
halomethylated or aminated cross-linked addition copolymer, the 
cross-linking agent is advantageously employed at greater than about 4, 
preferably greater than about 6, weight percent based on the weight of 
monomers employed in preparing said resin. 
In addition, aminated resins useful in the practice of this invention can 
be the cross-linked addition polymerization product of a suitable nitrogen 
containing compound. For example, the addition copolymerization product of 
vinylpyridine or vinylmethylpyridine, a cross-linking agent such as 
divinylbenzene, divinyl ketone or methylene bisacrylamide, and, 
optionally, a monovinylidene aromatic such as styrene, is useful as a weak 
base resin. A strong base resin is easily prepared therefrom by 
post-converting the resin to quaternary ammonium form. A strong base resin 
can also be prepared by the addition polymerization of a diallyl 
dimethylammonium chloride which polymerization may also include a 
cross-linking agent such as divinyl ketone. 
Alternatively, as disclosed by U.S. Pat. Nos. 2,469,684; 2,610,156 and 
2,614,085; all of which are hereby incorporated by reference, a weak base 
resin can be prepared by the condensation reaction of a polyamine, e.g., 
triethylenetetraamine, with an epoxide, e.g., epichlorohydrin. Similarly, 
the reaction of a polyamine with formaldehyde or an alkyl halide forms a 
weak base resin. 
Weak acid resins bearing carboxyl groups are easily prepared by 
conventional techniques well known in the art such as the techniques 
disclosed by U.S. Pat. Nos. 2,340,110 and 2,340,111, which are hereby 
incorporated by reference, wherein an organic acid such as acrylic or 
methacrylic acid is copolymerized with a cross-linking agent such as 
divinylbenzene or ethylene dimethacrylate. Alternatively, the weak acid 
resin can also be prepared by the method of U.S. Pat. No. 2,597,437, which 
is hereby incorporated by reference, wherein an ester of acrylic or 
methacrylic acid is copolymerized with a cross-linking agent and the 
copolymerization product subsequently hydrolyzed. 
Unless otherwise distinguished, the term "cross-linked polymer" as used 
herein, refers to non-treated or halomethylated cross-linked polymers as 
well as cross-linked polymers having active ion exchange groups. 
Preferably, the normally solid resins of the cross-linked polymers are 
prepared in spheroidal bead form, preferably with a diameter from about 
0.04 to about 2.4 mm, with a diameter from about 0.3 to about 1.2 mm being 
more preferred. 
The halo-olefins advantageously employed in this invention include 
vinylidene halide and vinyl halide; wherein the halide is bromine or 
chlorine or a mixture thereof. Of such halo-olefins, vinylidene chloride, 
vinylidene chlorobromide and vinylidene bromide are preferred, with 
vinylidene chloride being most preferred. 
The halo-olefin is employed in a sufficient amount such that the density of 
the heterogeneous ion exchange resin prepared therefrom is measurably 
increased and/or the crush strength of said heterogeneous resin is 
measurably improved. 
By the term "measurably increase the density of the heterogeneous ion 
exchange resin" it is meant that the density of said heterogeneous resin 
is increased by an amount measurable using conventional test methods, 
e.g., ASTM D-792-60T, when compared to an otherwise identically prepared 
ion exchange resin which does not have the halo-olefin polymerized 
therein. Preferably, the density increase is at least about 5 percent, 
more preferably at least about 10 percent. By way of example, a 
heterogeneous ion exchange resin exhibits a 5 percent increase in density 
when it has a density of 1.155 g/cc and are identically prepared ion 
exchange resin having no halo-olefin polymerized therein has a density of 
1.100 g/cc. 
By "measurably improve the crush strength of the heterogeneous ion exchange 
resin" is meant that the crush strength of said heterogeneous resin is 
increased by an amount measurable using conventional test methods, e.g., 
the test method described in Note 8 of Table I, when compared to an 
identical ion exchange resin having no halo-olefin polymerized therein. 
Preferably, crush strength improvement of the heterogeneous ion exchange 
resin is at least 2 times, more preferably 4 times the crush strength of 
an identical cross-linked addition copolymer which has no halo-olefin 
polymerized therein. 
Typically, the amount of the halo-olefin which is most advantageously 
employed will depend on various factors, including the composition of the 
resin, i.e., the type and concentration of monomers employed in preparing 
the cross-linked polymer; the type of said polymer, i.e., whether the 
cross-linked polymer is non-treated, haloalkylated or a polymer bearing 
pendant ion active groups, the polymerization conditions and the specific 
halo-olefin employed. In general, the halo-olefin is advantageously 
employed at from about 10 to about 50, preferably from about 20 to about 
40, most preferably from about 25 to about 35, weight percent, said weight 
percent being based on the total weight of the ethylenically unsaturated 
monomer and cross-linking agent employed in preparing the cross-linked 
polymer. 
In the practice of the present invention, the halo-olefinic monomer is 
imbibed by a normally solid particle, e.g., bead, or the cross-linked 
polymer and the imbibed monomer subsequently polymerized within the 
polymer's structure. Although said imbibition and polymerization of the 
halo-olefin within a non-treated or halomethylated cross-linked polymer 
may be conducted neat, advantageously, said polymer is advantageously 
first dispersed in water and the halo-olefin added thereto. Alternatively, 
the halo-olefin and water may be added simultaneously to the polymer. 
Generally, water is advantageously employed in amounts between about 50 
and about 300, preferably between about 100 and about 200, weight percent, 
said weight percent being based on the total weight of the ethylenically 
unsaturated monomer and cross-linking agent. 
Alternatively, the imbibition and polymerization of the halo-olefin within 
a cross-linked polymer having active ion exchange groups in non-ionic form 
is preferably conducted neat, i.e., no water is employed. In general, 
following the imbibition of the halo-olefin, the nonionic groups of the 
cross-linked polymer are advantageously placed in a protonated form prior 
to the polymerization of the halo-olefin. In general, this is readily 
accomplished by contacting the cross-linked polymer with sufficient 
amounts, e.g., amounts sufficient to convert essentially all the 
1.degree., 2.degree. and 3.degree. amine groups to a protonated form, of a 
suitable acid, preferably an essentially water free form of acid such as 
glacial acetic or phosphoric acid. 
On the other hand, the cross-linked polymer having active ion exchange 
groups in ionic form is preferably swollen by methanol or a like swelling 
agent prior to the imbibition of the halo-olefin. 
Although, in the preparation of the heterogeneous resin particles, the 
order of addition of the reactants is not critical, the halo-olefin and a 
polymerization initiator, either as separate feed streams or as a single 
mixture, are advantageously added batchwise to the cross-linked polymer or 
a mixture of said polymer and the aqueous reaction diluent. During said 
addition, the polymer is advantageously maintained at a temperature below 
those temperatures at which polymerization of the olefin can occur. 
Alternatively, the halo-olefin and the initiator can be added continuously 
to the polymer or mixture of the polymer and the reaction diluent while 
the polymer is maintained at a temperature sufficient to polymerize the 
halo-olefin. Batchwise addition of a mixture of the halo-olefin and the 
polymerization initiator is preferred. During said addition and the 
polymerization of the halo-olefin, the reactants, i.e., the halo-olefin 
and the cross-linked polymer, are advantageously maintained as an 
essentially uniform mixture, typically, by mild agitation. 
In the practice of the invention, the cross-linked polymer is swollen by 
the halo-olefin and the polymerization of the olefin conducted in the 
presence of a polymerization initiator while the polymer is in this 
swollen state. Polymerization initiators suitably employed herein include 
ultraviolet light, high energy radiation such as X-ray radiation, and 
conventional chemical initiators useful as free radical generators in the 
polymerization of halo-substituted olefins. Representative of such 
chemical initiators are the azo compounds, e.g., azobisisobutyronitrile; 
bisulfites; persulfates; peroxygen compounds, e.g., diisopropyl 
percarbonate and benzoyl peroxide; and the like. 
In general, the polymerization initiator is preferably a peroxygen 
compound. As the peroxygens have been found to give the greatest crush 
strength improvements, they are especially preferred as the polymerization 
initiator when the cross-linked copolymer is in a haloalkylated form. 
The initiator is suitably employed in an effective amount, i.e., an amount 
sufficient to cause polymerization of the halo-olefins. This effective 
amount is typically dependent on many factors, including the particular 
initiator and halo-olefin employed. Generally, an effective amount of the 
initiator is from about 0.05 to about 1.0, preferably from about 0.1 to 
about 0.3, weight percent, said weight percent being based on the total 
weight of the halo-olefin employed. 
The temperature at which polymerization is conducted is primarily dependent 
on the type of initiation. For example, with an initiator of diisopropyl 
percarbonate, the polymerization temperature is advantageously between 
about 25.degree. and 40.degree. C., whereas with an azobisisobutyronitrile 
initiator the polymerization is advantageously conducted at from about 
60.degree. to about 70.degree. C. In general, with other initiators the 
polymerization is conducted at a temperature between about 25.degree. and 
about 100.degree. C., with temperatures between about 40.degree. and about 
70.degree. C. being preferred. At these temperatures, polymerization 
generally requires from about 1 to about 10, preferably from about 2 to 
about 4, hours. 
When prepared from a cross-linked polymer having active ion exchange 
groups, depending on the nature of said groups, following polymerization 
of the halo-olefin the resulting heterogeneous resin is a weak or strong 
base (anion exchange) resin or a weak acid (cation exchange) resin. 
Alternatively, when a non-treated or halomethylated cross-linked polymer is 
employed in the preparation of the heterogeneous resin, following 
polymerization of the halo-olefin, the resulting heterogeneous resin is a 
precursor resin useful in the preparation of anion exchange or chelate 
type resins. 
In the preparation of anion exchange or chelate type resins from the 
heterogeneous precursor resin prepared from a non-treated cross-linked 
polymer, typically, prior to the attachment of active ion exchange groups 
thereto, the polymer is advantageously halomethylated by the techniques 
hereinbefore described. Preferably, ferric chloride is employed as the 
Freidel-Crafts catalyst in said halomethylation. 
Anion exchange resins are prepared from the halomethylated, heterogeneous 
precursor resin using aminating agents hereinbefore described. As the 
conditions at which the heterogeneous precursor resin is aminated 
influences the properties of the resulting aminated resin, i.e., water 
retention capability and specific gravity, the amination conditions are 
generally advantageously controlled to achieve the desired properties in 
the resulting resin. Although the conditions of amination hereinbefore 
described can be employed in the practice of this invention, in general, 
the halomethylated, heterogeneous precursor resin is advantageously 
aminated using relatively milder conditions, with the halomethylated 
heterogeneous precursor resin being slowly and continuously added to an 
excess amount of the aminating agent. Generally, said mild conditions for 
amination consist of times and temperatures which cause a slight darkening 
of the resin or cause a small percentage of the individual resin beads to 
blacken. In general, the amination is preferably conducted at temperatures 
between about 0.degree. and about 100.degree. C., with temperatures 
between about 10.degree. and about 60.degree. C. being more preferred, and 
for reaction periods from about 5 to about 120, more preferably from about 
15 to about 60, minutes. In general, amination is preferably conducted in 
a closed pressure vessel. 
Optionally, prior to amination, the halo-methylated heterogeneous precursor 
resin may be swollen by a relatively volatile, normally liquid, swelling 
agent such as methylene chloride, methanol, dioxane and 
1,2-dimethoxyethane. Excess swelling agent is removed by conventional 
techniques, e.g., filtration and the swollen beads then aminated. 
Any dehydrohalogenation of the olefin which may occur during amination or 
in the subsequent use of the resin can be compensated for by 
post-halogenating the polymerized halo-olefin using conventional 
techniques. 
Chelate resins are prepared from the halomethylated heterogeneous precursor 
resins by attaching thereto chelate active exchange groups, e.g., 
iminodiacetic groups. In general, conventional methods, such as those 
illustrated in U.S. Pat. No. 2,888,441, which is herein incorporated by 
reference, wherein a halomethylated precursor polymer is aminated by 
techniques hereinbefore described and the primary amine containing polymer 
subsequently reacted with a suitable carboxyl containing compound, e.g., 
chloroacetic acid, can be employed herein. Alternatively, the precursor 
polymer can be directly reacted with a suitable amino acid such as 
diaminoacetic acid or glycine (see, for example, U.S. Pat. Nos. 2,875,162 
and 3,337,480) or an aminopyridine such as 2-picolylamine and 
N-methyl-2-picolylamine (see U.S. Pat. No. 4,031,038), all of said 
references being hereby incorporated by reference, to form a chelate resin 
.

The following examples are presented to illustrate the invention and should 
not be construed to limit its scope. All percentages and parts are by 
weight unless otherwise indicated. 
EXAMPLE 1 
To a suitable size flask equipped with an agitator, thermometer and heating 
and cooling means, is added 352 g of dried, chloromethylated copolymer 
beads of 94 parts styrene, 6 parts divinylbenzene and 2.6 parts 
ethylvinylbenzene. The dried chloromethylated beads contain about 19.4 
weight percent chlorine, indicating that about 77.5 percent of the benzene 
rings have chloromethyl substituents. About 195 g of chilled vinylidene 
chloride is then added to the flask. The resulting mixture is mildly 
agitated at room temperature for about 30 minutes to allow the beads to 
swell in the vinylidene chloride. At the end of this period, the mixture 
is subjected to 5 mrad of gamma-ray radiation at a rate of 0.15 mrad per 
hour. 
At the end of this radiation period, the resulting heterogeneous resin 
beads are dried and the dried beads found to weigh 497 g and to contain 
about 41.2 weight percent chlorine. The amount of vinylidene chloride 
which has been polymerized in the heterogeneous head is calculated to be 
42.8 weight percent, based on the weight of the dry heterogeneous resin 
beads. 
The dried beads are swollen by methylene chloride and the swollen beads 
recovered by filtration, allowing the methylene chloride to remain within 
the beads. The swollen beads are then placed in a suitable size glass 
flask equipped with agitator, thermometer and heating and cooling means. 
To the flask is added 1000 g of a 10 weight percent aqueous solution of 
trimethylamine and the flask then closed. The resulting mixture is mildly 
agitated at room temperature, i.e., about 20.degree. C., until the beads 
darken slightly, which, in this case, takes about 30 minutes. At the end 
of this period, the methylene chloride is removed from the beads by 
distillation, adding deionized water at the same rate of the methylene 
chloride distillation. 
The beads are then washed with deionized water, acidified with hydrochloric 
acid to a pH of about 6 and separated by conventional filtration 
techniques. The filtered beads weigh 498 g, retain 50.3 percent water and 
have a wet density of 1.129 g/cc, which corresponds to a 4.5 percent 
increase in density over similar beads which have no vinylidene chloride 
polymerized therein. They have a wet volume capacity of 0.94 meq/ml 
(milliequivalents per milliliter) and dry weight capacity of 2.89 meq/g. 
In a similar manner, except that polymerization initiation consists of 10 
mrad of gamma-ray radiation, an aminated heterogeneous resin in bead form 
is prepared from 127 g vinylidene chloride and 70.7 g of chloromethylated 
beads. The resulting aminated, heterogeneous beads weight 182.5 g, retain 
40.6 percent water and have a density of 1.189 g/cc which corresponds to a 
density increase of about 10 percent. These beads exhibit a wet volume 
capacity of 0.91 meq/ml and dry weight capacity of 1.94 meq/g. 
As evidenced by the foregoing results, heterogeneous anion exchange resin 
beads prepared from a heterogeneous, chloromethylated resin by the method 
of this invention exhibit substantially increased densities when compared 
to conventional anion exchange beads. 
EXAMPLE 2 
To a suitable size flask similar to the flask of Example 1, is added 200 g 
of water and 100 g of dried, chloromethylated beads of a copolymer of 98.2 
parts styrene and 1.8 parts divinylbenzene. To the flask is then added a 
chilled mixture of 45 g vinylidene chloride and a polymerization initiator 
of 0.5 g diisopropyl percarbonate and 0.2 g azobisdimethylvaleronitrile. 
The resulting mixture is mildly agitated at 25.degree. C. for 20 hours, 
under a slow nitrogen purge, allowing the beads to imbibe the vinylidene 
chloride and to polymerize the imbibed vinylidene chloride. At the end of 
this period, the beads are dried and found to weigh 125 g. The beads are 
then aminated with trimethylamine in a manner similar to that of Example 1 
except that the heterogeneous beads are slowly and continuously added to 
the aqueous solution of the trimethylamine at 50.degree. C. The resulting 
aminated, heterogeneous beads are designated Sample No. 1. 
In a similar manner, several other samples (Sample Nos. 2-5) of aminated, 
heterogeneous resin beads are prepared using various amounts of vinylidene 
chloride as specified in Table I. 
As a control (Sample No. C), chloromethylated beads of 98.2 parts styrene 
and 1.8 parts divinylbenzene having no halo-olefin polymerized therein are 
aminated following the procedure of Example 1. 
The aminated beads are evaluated for percent polyvinylidene chloride, dry 
weight and wet volume capacity, density and percent water retention. The 
results of this evaluation are recorded in Table I. 
TABLE I 
__________________________________________________________________________ 
VeCl.sub.2 
Poly(VeCl.sub.2) 
Wet Vol. 
Dry Wt. 
H.sub.2 O In 
Wet Crush 
Crush 
Sample 
Charge 
Content, 
Capacity 
Capacity 
Beads 
Density 
Density 
Strength 
Strength 
No. % (2) 
% (3) Meg/ml (4) 
Meg/g (5) 
% (6) 
g/ml (7) 
Increase, % 
g (8) 
Improvement 
__________________________________________________________________________ 
(9) 
C* 
-- -- 1.27 4.33 55 1.078 
-- 0.9 -- 
1 47 39 0.91 1.59 24 1.251 
16.0 7.7 8.5 
2 44 28 0.83 1.58 25 1.24 15.0 16.7 18.5 
3(1) 
39 24 1.0 1.8 30 1.121 
4.0 21.4 23.8 
4 31 11 1.0 2.5 27 1.169 
8.4 20.2 22.4 
5 29 8 1.08 2.5 45 1.10 2.0 12.8 14.2 
__________________________________________________________________________ 
*Not an example of this invention 
(1)A 1 part portion per 100 parts of the dried chloromethylated beads of 
sodium phosphate is added with the polymerization initiator in the 
preparation of the heterogeneous beads to precipitate residual iron 
remaining from the chloromethylation of the beads, which iron causes 
wastage of the percarbonate polymerization initiator. 
(2)Vecl.sub.2 (vinylidene chloride) Charge is reported as a weight 
percent based on the weight of the chloromethylated copolymer beads. 
(3)Poly(VeCl.sub.2) Content refers to amount of vinylidene chloride 
polymer in the heterogeneous resin reported as a weight percent of 
poly(VeCl.sub.2) based on the total weight of the heterogeneous resin 
beads. 
(4)Determination of available ion exchange sites per unit weight (dry) 
which is measured by chloride titration with silver nitrate as described 
in DOWEX: Ion Exchange published in 1964 by The Dow Chemical Company, 
pages 37 and 38. 
(5)Determination of available ion exchange sites per unit weight (dry) 
which is measured by chloride titration with silver nitrate as described 
in DOWEX: Ion Exchange published in 1974 by The Dow Chemical Company, 
pages 37 and 38. 
(6)Water in the beads is the total weight percent water retained by the 
beads based on the weight of the beads and the water. 
(7)Wet density of the heterogeneous beads as determined by ASTM method 
designated D792-60T. 
(8)Crush strength is the number average crush strength of the individual 
crush strengths of a sample comprising at least about 10 beads, each bead 
having a particle diameter of 0.5 mm .+-. 0.05 mm, wherein crush strength 
is the total force required to crush each bead as measured by an Instron 
tester at a crosshead speed of 0.05 cm per minute. 
(9)Crush strength improvement is reported as the number by which the 
crush strength of Sample C must be multiplied to obtain the crush strengt 
of the respective Sample Nos. 1-5. 
As evidenced by the data in the foregoing Table, the aminated heterogeneous 
resin beads prepared from heterogeneous chloromethylated beads by the 
method of this invention exhibit significant crush strength improvement 
and density increases. The amount of crush strength improvement and 
density increase is shown to be dependent on the amounts of the 
polymerized vinylidene chloride in the heterogeneous resin beads. Said 
amount of polymerized vinylidene chloride is also shown to influence the 
other properties of the resin. 
EXAMPLE 3 
To a suitable size flask similar to the one employed in Example 1, is added 
69 g of wet chloromethylated, cross-linked copolymer beads (50 g dry) of 
88.5 parts styrene, 8 parts divinylbenzene and 3.5 parts ethylvinylbenzene 
containing about 18.1 percent chlorine, indicating about 70 percent of the 
benzene rings have chloromethyl substituents. To the flask is then added a 
chilled mixture of 21.5 g vinylidene chloride, 0.04 g of diisopropyl 
percarbonate and 81.1 g of water. The vessel is closed and the resulting 
mixture agitated mildly with a slow nitrogen purge for 18 hours at 
40.degree. C. At the end of this period, the resulting heterogeneous resin 
beads are recovered by filtration and dried. The dry heterogeneous beads 
weigh 68.6 g and contain about 23 percent by weight of polymerized 
vinylidene chloride. 
The dried beads are swollen by methylene chloride and the swollen beads 
recovered by filtration. The swollen beads are then placed in a flask 
similar to the amination flask used in Example 1. To the flask is then 
added about 400 g of a 25 weight percent aqueous solution of 
trimethylamine. The flask is closed and the mixture is mildly agitated for 
one hour without external heating. During this period the temperature of 
the flask rises to about 40.degree. C. and the beads darken slightly. The 
methylene chloride is then removed from the beads. 
The resulting aminated, heterogeneous resin is a weak base ion exchange 
resin in bead form having a wet volume capacity of 1.08 meq/ml, a dry 
weight capacity of 3.39 meq/g and retains about 29 percent water. The 
heterogeneous resin beads have a wet density of 1.176 g/cc, an increase of 
about 8 percent when compared to a similar resin having no vinylidene 
chloride polymerized therein. 
EXAMPLE 4 
To a suitable size flask equipped with stirrer, reflux condenser, 
thermometer and heating and cooling means is added 100 g of a dry, 
cross-linked copolymer of 96 parts styrene and 4 parts divinylbenzene. To 
the flask is then added 30 g of vinylidene chloride and 0.5 g of 
azobisisobutyronitrile. The resulting mixture is mildly agitated for 
several hours at room temperature and then heated under pressure in a 
closed vessel for 22 hours at 70.degree. C. At the end of this period, the 
resulting non-treated heterogeneous resin beads are recovered by 
filtration, yielding 126 g of beads after drying. 
A 100 g portion of the recovered beads are transferred to a suitable size 
flask similar to the flask employed in the polymerization of the 
vinylidene chloride. To the flask is added 500 ml of chloromethyl ether. 
The resulting mixture is mildly agitated for about 60 minutes at a 
temperature of about 25.degree. C., thereby allowing the heterogeneous 
resin beads to swell in the chloromethyl ether. At the end of this period, 
86 g of zinc chloride is added to the flask. The flask is then heated to 
about 50.degree. C. and maintained at that temperature for 6.5 hours. 
Following this period, the flask is cooled to room temperature and the 
chloromethylated heterogeneous resin beads recovered by filtration. The 
chloromethyl ether is distilled off and the beads washed with methanol 
twice. 
The chloromethylated heterogeneous resin beads are then aminated following 
the procedure of Example 2. The resulting aminated, heterogeneous resin is 
a weak base ion exchange resin in bead form and is designated Sample No. 
1. 
In a similar manner, other heterogeneous weak base ion exchange resins in 
bead form (Sample Nos. 2 and 3) are prepared using the various amounts of 
vinylidene chloride as recorded in Table II. As a control, a similar 
aminated resin bead is prepared except that no vinylidene chloride is 
polymerized therein (Sample No. C). Each sample of beads is tested for wet 
volume and dry weight capacity, density, percent water content and crush 
strength. The results of this testing are recorded in Table II. 
TABLE II 
__________________________________________________________________________ 
VeCl.sub.2 
Poly(VeCl.sub.2) 
Wet Vol. 
Dry Wt. 
H.sub.2 O In 
Wet 
Sample 
Charge 
Content, 
Capacity 
Capacity 
Beads 
Density 
Density 
No. % (1) 
% (2) Meg/ml (3) 
Meg/ml (4) 
% (5) 
g/ml (6) 
Increase, % 
__________________________________________________________________________ 
C* 
-- -- 1.2 4.0 56.0 
1.06 -- 
1 30 15.2 1.23 3.35 46.0 
1.098 
3.8 
2 40 14.7 1.22 3.25 44.5 
1.102 
4.2 
3 50 14.6 1.22 3.15 51.0 
1.115 
5.4 
__________________________________________________________________________ 
*Not an example of the present invention. 
(1)Same as (2) in Table I 
(2)Same as (3) in Table I 
(3)Same as (4) in Table I 
(4)Same as (5) in Table I 
(5)Same as (6) in Table I 
(6)Same as (7) in Table I 
(7)Same as (8) in Table I 
As evidenced by the data recorded in Table II, heterogeneous weak base 
resins in bead form having increased density are shown to be effectively 
prepared by imbibing vinylidene chloride into non-treated heterogeneous 
resin beads and subsequently attaching anion active exchange groups 
thereto. The amount of density increase as well as the other resin 
properties are shown to be dependent on the amounts of the polymerized 
vinylidene chloride in the heterogeneous resin beads. 
EXAMPLE 5 
Several aminated, heterogeneous resins in bead form (Sample Nos. 1-4) are 
prepared from a copolymer of 96 parts styrene and 4 parts divinylbenzene 
following the procedure of Example 4 except that the various amounts of 
vinylidene chloride as recorded in Table III are employed and ferric 
chloride is used as the catalyst (in place of zinc chloride) at the 
amounts specified in Table III during chloromethylation of the 
heterogeneous resin beads. As a control, similar aminated resin beads are 
prepared except that no vinylidene chloride is polymerized therein (Sample 
No. C). The resulting aminated, resin beads are evaluated for wet volume 
capacity, wet density and water content, which evaluation results are 
recorded in Table III. 
As evidenced by the data in Table III, the conditions of halomethylating a 
non-treated halomethylated resin having the halo-olefin polymerized 
therein are shown to effect the density increases and other properties 
exhibited by the heterogeneous ion exchange resin beads prepared 
therefrom. 
TABLE III 
__________________________________________________________________________ 
VeCl.sub.2 
Poly(VeCl.sub.2) 
FeCl.sub.3 
Wet Vol. 
H.sub.2 O In 
Wet 
Sample 
Charge 
Content, 
Charge 
Capacity 
Beads 
Density 
Density 
No. % (1) 
% (2) % (3) 
Meg/ml (4) 
% (5) 
g/ml (6) 
Increase, % 
__________________________________________________________________________ 
C* 
-- 44.7 -- 1.2 56 1.06 -- 
1 45 44.7 34 0.59 14 1.347 
27 
2 45 44.7 20 1.58 39 1.16 9.2 
3 30 27.9 34 1.57 44 1.098 
3.5 
4 30 27.9 17 1.33 44 1.109 
4.8 
__________________________________________________________________________ 
*Not an example of the present invention. 
(1)Same as (2) in Table I 
(2)Same as (3) in Table I 
(3)FeCl.sub.3 charge is reported as a weight percent based on the total 
weight of the crosslinked, addition copolymer beads. 
(4)Same as (4) in Table I 
(5)Same as (6) in Table I 
(6)Same as (7) in Table I 
EXAMPLE 6 
To a 120 cc bottle is added 25 g of vinylidene chloride and 46.7 g of dried 
strong base ion exchange resin beads in the Cl.sup.- form derived from 
88.5 parts styrene, 8 parts divinylbenzene and 3.5 parts ethyl 
vinylbenzene. The resulting mixture is slowly agitated for about 60 
minutes to allow the resin beads to imbibe the vinylidene chloride. At the 
end of this period, the mixture is exposed to 5 mrad of gamma-ray 
radiation at a rate of 0.22 mrad/hr. After this treatment, the resulting 
aminated, heterogeneous resin beads are recovered by filtration and dried. 
They weigh 46.7 g. The beads have a wet volume capacity of 1.17 meq/ml, 
and a dry weight capacity of 2.85 meq/g. The beads also have a 34.5 
percent water content and a wet density of 1.206 g/cc, which represents an 
11 percent density increase when compared to a similar strong base resin 
in bead form which has no vinylidene chloride polymerized therein. 
As shown by this example, a heterogeneous anion exchange resin having an 
increased density can be effectively prepared by imbibing and subsequently 
polymerizing a halo-olefin within a cross-linked polymer having anion 
active exchange groups. 
EXAMPLE 7 
To a suitable size flask similar to the flask employed in Example 1 is 
added 250 g of a dry chloromethylated macroporous copolymer resin of 88.7 
parts styrene, 6 parts divinylbenzene and 4.3 parts ethyl vinylbenzene. To 
the flask is then added a chilled mixture of 250 g of vinylidene chloride 
and 1.0 g of azobisisobutyronitrile. The resulting mixture is mildly 
agitated for 4 hours at room temperature to allow the resin to imbibe the 
vinylidene chloride. At the end of this period, the flask is heated to 
65.degree. C. and maintained at this temperature for 16 hours. At the end 
of this period, the beads are dried and the dried beads found to weigh 500 
g. The beads are then aminated with trimethylamine in a manner similar to 
Example 1. The aminated beads are designated Sample No. 1. 
A 20 g portion of the resulting aminated beads are placed in a transparent 
60 cc bottle containing an open vial of liquid bromine. The bottle is 
placed in direct sunlight for a period of about 8 hours. During this 
period, the beads darken and some hydrogen bromide is formed. After this 
period, the beads are alternately washed with a 5 weight percent solution 
of hydrochloric acid and water until the rinse water contains essentially 
no halide ion. The beads are then recovered using conventional techniques. 
The recovered, post-brominated beads are designated Sample No. 2. 
Both Sample Nos. 1 and 2 and a control (Sample No. C) are evaluated for 
percent polymerized vinylidene chloride, dry weight and wet volume 
capacity, density and percent water retention. The results of this 
evaluation are recorded in Table IV. 
As evidenced by the data in Table IV, the heterogeneous resin beads are 
easily post-brominated, i.e., following amination of the copolymer bead, 
to produce an ion exchange resin having a further increased density. 
TABLE IV 
__________________________________________________________________________ 
Poly(VeCl.sub.2) 
Wet Vol. 
Dry Wt. 
H.sub.2 O In 
Wet 
Sample 
Content, 
Capacity 
Capacity 
Beads 
Density 
Density 
No. % (1) Meg/ml (2) 
Meg/g (3) 
% (4) 
g/ml (5) 
Increase, % 
__________________________________________________________________________ 
C* 
-- 1.27 4.33 55 1.078 
-- 
1 39 0.9 2.91 45.7 
1.15 6.9 
2 39 0.79 2.11 38.7 
1.33 23.5 
__________________________________________________________________________ 
*Not an example of this invention. 
(1)Same as (3) in Table I 
(2)Same as (4) in Table I 
(3)Same as (5) in Table I 
(4)Same as (6) in Table I 
(5)Same as (7) in Table I 
EXAMPLE 8 
To a suitable size flask similar to the flask employed in Example 1 is 
added 70 g of dry weak base resin beads of a copolymer of 88.7 weight 
percent styrene, 6 weight percent divinylbenzene and 4.3 weight percent 
ethyl vinylbenzene which copolymer bears dimethylaminomethyl groups. To 
the flask is then added a chilled mixture of 30 g of vinylidene chloride 
and 0.06 g azobisisobutyronitrile. The mixture of vinylidene chloride is 
quickly imbibed by the beads. Following this imbibition, 15.1 g of glacial 
acetic acid is added to the flask to convert the dimethylaminomethyl 
groups to a protonated form. The imbibed vinylidene chloride is 
polymerized by heating the beads for fifteen hours at about 60.degree. C. 
After this period, the beads are dried and found to contain 24.3 percent, 
by weight of polymerized vinylidene chloride. The beads are rinsed with a 
5 weight percent hydrochloric acid solution and then washed with water 
until the rinse water is essentially halide free. The resin is found to 
contain 48 percent water, a wet volume capacity of 1.38 meq/ml and a 
specific gravity of 1.16, which represents a density increase of about 8 
percent over a similar weak base resin having no vinylidene chloride 
polymerized therein.