Stable high solids water-in-oil slurry dispersion composition

This invention provides a non-gelling water-in-oil high solids slurry dispersion of water-soluble polymer. The slurry dispersion composition contains between about 40-80 weight percent of water-soluble polymer, and is prepared by dehydrating a water-in-oil dispersion of synthetic water-soluble polymer, and then slurrying a quantity of finely divided water-soluble polymer into the dehydrated dispersion.

BACKGROUND OF THE INVENTION 
Various synthetic and natural water-soluble polymers have been developed 
which exhibit superior thickening and flocculating properties in aqueous 
solutions. These polymers are being used increasingly in a number of 
commercial applications such as in the clarification of aqueous systems, 
in paper making operations, in the treatment of sewage and industrial 
waste, in stabilizers for drilling muds, and in the secondary recovery of 
petroleum by water flooding. 
Although these polymers are available commercially as powders or as finely 
divided solids, they are most frequently utilized as aqueous solutions. 
This requires the solid polymer material to be dissolved in water. This is 
a time consuming step as well as one which has serious drawbacks with 
respect to the actual dispersion of solids into the aqueous media. 
Water-in-oil emulsions having finely divided water-soluble polymers 
dispersed therein are known in the art. The primary disadvantage of such 
emulsions is that attempted further treatment of such emulsions generally 
results in coagulation or agglomeration of the polymer whereby the polymer 
does not remain finely divided and dispersed in the emulsion. 
Attempts to add surfactant to such emulsions to render the emulsions self 
inverting, whereby the polymer can be dispersed in aqueous solutions, have 
generally not been successful as a result of coagulation or agglomeration 
of the polymer. As a result, usually such emulsions are inverted into 
water by separately adding the surfactant and emulsion to the water, which 
necessitates separate shipping and handling of two products. 
In U.S. Pat. Nos. 3,624,019 and 3,734,873, it is indicated that it is 
possible in some cases to prepare a self inverting water-in-oil emulsion 
having finely divided polymer and surfactant dispersed therein. However, 
there are limitations in that the addition of the surfactants may tend to 
interact with the emulsifier or emulsion and destroy it prior to use 
thereof. 
Prior art references of interest relative to the present invention are 
those which are concerned with the production of stable water-in-oil 
emulsions of water-soluble polymers which are adapted for self inversion 
in aqueous solutions. 
U.S. Pat. No. 4,052,353 describes a self water dissolving composition of a 
water-soluble polymer dispersed in oil which is comprised of (1) a 
water-in-oil dispersion of a water-soluble polymer, wherein the water 
content of the dispersion has been reduced by distillation to less than 40 
weight percent; and (2) a water-soluble surfactant having an HLB number 
above 8. 
Other prior art of interest relating to dispersions of water-soluble 
polymer in oil include U.S. Pat. Nos. 3,282,874; 3,691,124; 3,826,771; 
3,849,361; 3,888,945; 4,021,399; 4,024,097; 4,029,622; 4,090,992; 
4,125,508; 4,176,107; and 4,299,755. 
There is continuing interest in the development of stable water-in-oil type 
dispersions of water-soluble polymers which are dispersible in aqueous 
solutions, and which preferably have a high solids content of 
water-soluble polymer. 
Accordingly, it is an object of this invention to provide a stable 
water-in-oil dispersion of water-soluble polymer which is readily 
dispersible in aqueous media. 
It is another object of this invention to provide a process for the 
production of a non-gelling water-in-oil dispersion of water-soluble 
polymer, which dispersion contains more than about 40 weight percent of 
water-soluble polymer. 
Other objects and advantages of the present invention shall become apparent 
from the accompanying description and examples. 
DESCRIPTION OF THE INVENTION 
One or more objects of the present invention are accomplished by the 
provision of a process for the production of a non-gelling water-in-oil 
high solids slurry dispersion of water-soluble polymer which comprises (1) 
subjecting a water-in-oil dispersion of synthetic water-soluble polymer to 
distillation to reduce the water content to less than about 15 weight 
percent of the dispersion; and (2) slurrying a quantity of finely divided 
solid water-soluble polymer into the step (1) water-reduced dispersion to 
provide a slurry dispersion containing between about 40-80 weight percent 
of water-soluble polymer, based on the weight of the slurry dispersion 
composition. 
The term "water-soluble polymer" refers to polymers and copolymers which 
are at least partially soluble in water at 25.degree. C., and the term is 
meant to include polymers which are water-dispersible. 
Illustrative of synthetic water-soluble polymers amenable to the step (1) 
procedure are those disclosed in U.S. Pat. No. 4,052,353, such as homo and 
copolymers of acrylamide, methacrylamide, acrylic acid, methacrylic acid, 
crotonic acid, fumaric acid, maleic anhydride, vinyl pyridine, quaternary 
and amino substituted acrylates, sulfoalkyl acrylates, vinyl benzene 
sulfonic acid and the like. Such monomers can be copolymerized with other 
monomers, such as alkyl acrylates and methacrylates, styrene, vinyl 
toluene, vinyl chloride and the like. 
The finely divided solid water-soluble polymer employed in the step (2) 
slurrying procedure can be selected from the types of synthetic 
water-soluble polymers enumerated above, and additionally can be selected 
from natural and semi-synthetic polymers such as cellulose and 
polygalactomannan gums and their semi-synthetic derivatives. Illustrative 
of this type of polysaccharides are hydroxyethylcellulose, 
carboxymethylcellulose, guar gum, locust bean gum, xanthan gum, 
hydroxypropyl guar, carboxymethyl guar and the like. 
A water-soluble polymer selected for purposes of the present invention 
typically will have a molecular weight of at least about 100,000. 
The oil phase of the invention slurry dispersion compositions can be 
essentially any water-immiscible organic liquid which is compatible with 
the water-in-oil nature of the compositions. Suitable liquid organic media 
include hydrocarbons and substituted hydrocarbons such as benzene, 
toluene, xylene, kerosene, mineral oil, naphtha, perchloroethylene, 
chlorobenzene, nitrobenzene, and the like. Other organic liquids, such as 
dibutyl ether and ethylhexyl ketone can also be used. It is desirable that 
a water-immiscible solvent or solvent mixture employed as the oil phase 
does not dissolve more than about one percent of any water-soluble polymer 
which is dispersed in a slurry dispersion composition. 
The starting water-in-oil dispersion of synthetic water-soluble polymer 
that is subjected to distillation in step (1) of the present invention 
process can be prepared by any one of a wide variety of procedures, and is 
preferably prepared by the water-in-oil emulsion polymerization technique 
for preparation of vinyl addition polymers. In accordance with such a 
procedure, a water-in-oil emulsion of water-soluble ethylenically 
unsaturated monomer(s) is formed and polymerized under free radical 
polymerization conditions to produce a latex of water-in-oil emulsion 
having finely divided polymer dispersed therein. A representative example 
of this technique is disclosed in U.S. Pat. No. 4,176,107 and several of 
the other references recited in the Background of the Invention section 
above. 
Alternatively, a water-in-oil emulsion having finely divided water-soluble 
polymer dispersed therein can be prepared by dispersing previously 
prepared polymer in a water-in-oil emulsion. Such techniques involve 
comminuting the polymer to provide finely divided polymer and then 
dispersing the polymer in a water-in-oil emulsion by means of suitable 
agitation. In most cases, a suitable oil-soluble emulsifying agent is used 
in preparing the emulsion. The emulsifier should be inert with respect to 
the components present in the emulsion or used in the subsequent 
treatment, and generally will have an HLB under (Hydrophilic-Liphophilic 
Balance) below about 10. 
The starting water-in-oil dispersion described above normally will contain 
above about 25 weight percent of each of the oil and water constituents, 
and above about 20 weight percent of the water-soluble polymer 
constituent. 
It is highly preferred that the water-soluble polymer in the starting 
water-in-oil dispersion in step (1) has a particle size that is less than 
about 10 microns. A water-soluble polymer with a particle size higher than 
about 10 microns has a greater tendency to agglomerate under distillation 
conditions. 
With respect to the distillation procedure in step (1) to reduce the water 
content to less than about 15 weight percent of the dispersion, in the 
usual case the overhead distillate will be in the form of a water-oil 
azeotrope. The oil phase (e.g., kerosene) is readily recoverable for 
recycle. The distillation may be run at atmospheric pressure but most 
preferably under reduced pressures. 
In most cases it can be advantageous to include additional oil phase prior 
to the distillation procedure, or recycle it continuously or 
intermittently during the distillation as convenient or necessary. If the 
volume of oil phase is low at any time during the distillation, gelation 
of the water-in-oil dispersion may occur. 
With respect to step (2) of the invention process wherein a quantity of 
finely divided solid water-soluble polymer is slurried into the 
water-reduced dispersion intermediate from step (1), the procedure is 
facilitated by efficient agitation and by the presence of a surfactant. 
The particle size of the solid water-soluble polymer being slurried into 
the dehydrated dispersion can be greater than 10 microns, e.g., the 
particles can be as large as 50-1000 microns in size. 
If the finely divided solid water-soluble polymer is added directly to 
water-in-oil dispersion of synthetic water-soluble polymer without going 
through step (1) gelation of the mixture usually occurs within 24 hours. 
The inclusion of a surfactant is advantageous for purposes of facilitating 
the rapid hydration of the slurry dispersion composition. The surfactant 
is employed in a quantity between about 0.1-20 weight percent, based on 
composition weight. If desired, a mixture of surfactants can be employed, 
e.g., one surfactant having an HLB below about 8, and another having an 
HLB above about 10. 
Suitable surfactants are those selected from cationic, anionic and nonionic 
materials such as those described in U.S. Pat. Nos. 3,624,019; 4,021,399; 
4,176,107; and references cited therein. Illustrative of surfactants are 
alkylene oxide adducts of linear alcohols and alkylphenols, sorbitan 
esters, ethoxylated sorbitan esters, fatty acid esters of polyalkylene 
oxides, ethoxylated fatty amides, alkyl sulfates and sulfonates, phosphate 
esters of ethoxylated linear alcohols and alkylphenols, long chain 
quaternary amines, olefin/N-vinyl/pyrrolidine copolymers and the like. 
In a further embodiment, the present invention contemplates the inclusion 
of a finely divided inorganic substrate as an additional component. 
Particularly desirable is the inclusion of a stabilizer (e.g., an 
anti-settling agent) such as clay or silica. Other suitable inorganic 
fillers are pigments such as calcium carbonate, titanium dioxide, and the 
like. The inorganic material is employed in a stablizing quantity, such as 
between about 0.5 and 10 weight percent, based on the weight of slurry 
dispersion composition. If some settling does occur on long standing, it 
is readily redispersed by suitable agitation. 
A water-in-oil high solids slurry dispersion composition of the present 
invention is suitable for the preparation of aqueous polymer solutions, 
preferably as a flocculant in various mineral processing operations, as a 
retention aid for fillers and water-removal accelerators in the production 
of paper, and also as a size for textiles or as a protective colloid. They 
are also suitable for various oil recovery operations.

The following Examples are further illustrative of the present invention. 
The reactants and other specific ingredients are presented as being 
typical, and various modifications can be devised in view of the foregoing 
disclosure within the scope of the invention. 
EXAMPLE I 
To a 1 liter three-neck flask equipped with stirrer and vacuum distillation 
apparatus are added 400 grams of a polyacrylamide inverse emulsion.sup.(1) 
containing about 28 weight percent polyacrylamide and about 40 weight 
percent water. To this are added dropwise 75 grams of kerosene. The 
emulsion is then subjected to vacuum distillation to remove water. A total 
of 159.1 grams of water-hydrocarbon azeotrope are removed at a final 
manometer reading of 8 mm Hg and a final temperature of 37.degree. C. The 
azeotrope distillate contains 85 weight percent water. The milky 
dispersion remaining in the flask has a calculated water content of 7.9 
weight percent and a calculated polymer content of 35.5 weight percent. It 
contains essentially no gel particles. 
FNT .sup.(1) American Cyanamid's 1320. 
EXAMPLE II 
Employing the same procedure of Example I, four inverse emulsions are 
dehydrated in accordance with step (1) of the invention process. 
The compositions of the water-in-oil dispersions, before and after 
dehydration, are listed in Table I. 
TABLE I 
__________________________________________________________________________ 
INVERSE DEHYDRATED 
EMULSION DISPERSION Grams 
DISPERSION 
Water-Soluble 
% % % % Grams 
Kerosene 
% % % 
Number 
Polymer Polymer 
H.sub.2 O 
HC Surfact. 
Charge 
Added 
H.sub.2 O 
Polymer 
HC 
__________________________________________________________________________ 
1 Ammonium 29.9 27.2 
28.8.sup.(1) 
5.7 400 100 5.45 
32.7 47.9 
Polyacrylate 
2 60/40 29.8 26.0 
28.6.sup.(1) 
6.0 402.5 
100 6.1 
31.3 52.6 
Acrylamide/ 
Acrylic Acid 
3 95/5 31.3 31.0 
28.3.sup.(1) 
3.5 459.5 
100 9.2 
34.8 45.7 
Acrylamide/ 
Acrylic Acid 
4 95/5 31.2 31.2 
28.3.sup.(2) 
3.9 461 75 9.2 
35.5 44.6 
Acrylamide/ 
Ageflex FA-2Q.sup.(3) 
__________________________________________________________________________ 
.sup.(1) Odorless Mineral Spirits 
.sup.(2) Kerosene 
.sup.(3) Dimethyl sulfate quat of 2Diethylaminoethyl methacrylate; C.P.S. 
EXAMPLE III 
This Example illustrates the preparation of a high solids slurry dispersion 
composition in accordance with the present invention process. 
A dehydrated 95/5 acrylamide/acrylic acid copolymer dispersion is prepared 
in the manner of Number 3 in Example II, except that it contains 9.0% 
water and 35.2% polymer. 
To 50 grams of this dehydrated dispersion are added with stirring 17.6 
grams of Natrosol 250 HR.sup.(1) premixed with 1.0 gram of Bentone 
38.sup.(2). The slurry dispersion is stirred for 15 minutes, then 1 gram 
of Triton X-114.sup.(3) is added and stirring is continued for an 
additional 15 minutes. The resulting smooth slurry dispersion composition 
contains 50.6% by weight total polymer with a 1:1 weight ratio of 
hydroxyethylcellulose; acrylamide/acrylic acid copolymer, based on the 
weight of slurry dispersion composition. 
FNT .sup.(1) Hydroxyethylcellulose; Hercules. 
FNT .sup.(2) Organic derivative of a special smectite clay; NL. 
FNT .sup.(3) Octylphenoxypolyethoxy ethanol; HLB=12.4; Rohm and Haas. 
EXAMPLE IV 
To 50 grams of the dehydrated dispersion of Example I are added 41.4 grams 
of powdered guar gum, premixed with 0.5 gram Bentone 38, with stirring. 
After stirring 15 minutes, 1.0 gram of Triton X-114 is added and stirring 
is continued for another 15 minutes. The resulting smooth slurry 
dispersion contains 63.7% by weight total polymer with a 7:3 weight ratio 
of guar:polyacrylamide. 
If the guar gum is added directly to the polyacrylamide inverse emulsion 
which has not been dehydrated, gelation occurs before all the guar gum is 
added. 
In a similar manner, a 50 gram quantity of a dehydrated polyacrylamide 
containing 9.7% by weight water and 38.2% by weight polymer is slurried 
with 38.2 grams of solid polyacrylamide (Percol 351; Allied Colloids) 
which has been premixed with 0.75 gram of Bentone 38. 
After 10 minutes of stirring, 1.0 gram of Triton X-114 is added and 
stirring is continued for another 10 minutes. The resulting slurry 
dispersion composition contains 63.7% by weight of polyacrylamide. 
If the second stage solid polyacrylamide is added to the same 
polyacrylamide water-in-oil emulsion, except that it has not been 
dehydrated in accordance with Example I, then gelation occurs before all 
of the solid polyacrylamide is added. 
EXAMPLE V 
To 50 grams of the Number 4 dehydrated dispersion of Example II are added 
41.5 grams of powdered guar gum, premixed with 0.5 gram Bentone 38, with 
stirring. After stirring 15 minutes, 1.0 gram of Triton X-114 is added, 
and stirring is continued for another 15 minutes. The smooth 
slurry-dispersion contains 65.8% total polymer with a 7:3 weight ratio of 
guar:acrylamide/FA-2Q copolymer. 
EXAMPLE VI 
Two present invention slurry dispersion compositions based on guar 
gum-polyacrylamide are evaluated vs. dry blends of guar gum-polyacrylamide 
as flocculants for acid-leached South African uranium ore. The results are 
summarized in Table II. 
The data in Table II demonstrate that the slurry dispersion compositions in 
accordance with the present invention provide better efficiencies than the 
corresponding dry blended polymers, and provide the added convenience of 
being in a liquid form. 
TABLE II 
______________________________________ 
Relative 
Efficiency* 
______________________________________ 
1:1 Guar gum:Polyacrylamide Slurry Dispersion, 
0.87 
54.2% total polymer 
7:3 Guar gum:Polyacrylamide Slurry Dispersion, 
0.94 
69.1% total polymer 
1:1 Guar gum:Polyacrylamide Dry Blend 
1.00 = Std. 
7:3 Guar gum:Ployacrylamide Dry Blend 
1.03 
______________________________________ 
*Pounds of polymer to obtain same floc settling rate at 1 pound of the 
standard. 
EXAMPLE VII 
Tables III and IV summarize the physical characteristics of paper prepared 
utilizing a slurry dispersion composition of the present invention as a 
retention and strength aid. It is compared with its individual polymer 
components. 
TABLE III 
______________________________________ 
1:1 Hardwood:Softwood 
pH 5.5, 10% Clay, 30 lbs. alum/ton of paper 
Polymer 
Level % 
Lbs./Ton 
Retention 
______________________________________ 
Blank -- 27.55 
95/5 Acrylamide/Acrylic Acid 
0.3 69.63 
Inverse Emulsion 1.0 82.30 
Guar Gum 0.7 36.36 
1.0 39.07 
Slurry-Dispersion of 7:3 Guar Gum: 
0.5 67.44 
95/5 Acrylamide/Acrylic Acid, 
1.0 71.85 
61.5% Polymer 
______________________________________ 
TABLE IV 
______________________________________ 
1:1 Hardwood:Softwood 
pH 5.5, 30 lbs. alum/ton of paper 
Polymer 
Strength 
Level Internal Corrected Corrected 
Lbs./Ton 
Bond Mullen Tensile 
______________________________________ 
Blank -- 44.4 17.5 11.5 
95/5 Acrylamide/ 
1.8 63.5 20.2 12.8 
Acrylic Acid 
6.0 78.0 20.8 12.5 
Inverse Emulsion 
Guar Gum 4.2 58.9 19.2 13.7 
6.0 57.6 19.4 12.8 
Slurry-Dispersion 
3.0 76.1 19.5 12.8 
of 7:3 Guar Gum: 
6.0 82.0 22.2 12.7 
95/5 Acrylamide/ 
Acrylic Acid, 
61.5% Polymer 
______________________________________ 
The principles, preferred embodiments and modes of operation of the present 
invention have been described in the foregoing specification. The 
invention which is intended to be protected herein, however, is not to be 
construed as limited to the particular forms disclosed, since these are to 
be regarded as illustrative rather than restrictive. Variations and 
changes may be made by those skilled in the art without departing from the 
spirit of the invention.