Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
- 2 ~ 5~3~
H0 83/F 222
The present invention relates to copoLymers as
d;spersing agents for solidsO preferably in aqueous solu-
tion. The solids can differ greatly in nature, and their
concentrations in the liquid phase can vary to a very
considerable degree~ Thus, the compounds according to
the invention disperse solids in concentrations of a few
mg/l ~ust as effectively as in systems with a high solids
content, for example drilling muds and mineral binders,
such as cement and gypsum sLurries and kaol;n, carbon and
calcium carbonate slurries and the like~ sometimes with
extremely low solvent contents. In the case of the highly
concentrated dispersions of solids, the compounds accor-
ding to the invention enable the water content to be mini~
mi~ed and the v;scosity to be reduced, which offers indus-
trial advantages.
Very different dispers;ng auxiliaries are used
to opt;mize the properties of the most diverse disper-
sions, such as drilling muds, cement slurrie3~ carbon
slurr;es and d;spersions of pesticides and color pigments.
Dispersing agents which are used in drill~ng muds
are, for example, polyphosphates~ quebracho and, in par-
ticular, lignosulfonates and lignites, for example in
accordance with German ALIS legeschrift 1,1 3,874. Copoly-
mers of styrene sulfonate and maleic anhydride according
25 to U.S. Patent No. 3,730,900 have recently found use in
the field of drilling mudsO as liquefiers for high
temperatures.
If saline water has to be used -for drilling muds
when drilling through salt formations or when drilling in
the open sea, protective colloids, such as starch and
starch derivatives, carboxymethylhydroxyethyl-carboxy-
methylcellLIloses~ biopolymers and partly hydrolyzed acryl-
amicles are necessary for stabilizing these dispersions.
At very h;gh solids contents, low molecular weight ionic
polymers are preferred. The use of additives for drilling
muds is descr;bed ;n great cletail in: George ~ Gray,
3 ~ i8~7
H~C~Ho Darly, Walter F. Rogers "Composition and Properties
of Oil Well Drilling Fluids, Fourth Edition~ Gulf
Publishing Company Houston/Texas 1980.
Copolymers of v;nyl sulfonate and vinylamide
according to German Offenlegungsschrift 2,931,897 and
German Auslegeschrift 2,444S108 haue recently proved par-
ticularly suitable, when used in saline dri~ling muds,
for stabilizing properties established beforehand in very
deep hot bores.
In cement slurries which are pumped, d;spersing
agents reduce the v;scos;ty~ Th;s fac;litates the pum-
ping operation and enables the water content ~o be re-
duced, which improves the mechanical properties of the
hardened concrete. Lignosulfonates, polyacryLic acids,
condensation products of mononaphthalenesulfonates and
formaLdehyde according to U.S. Patent 3,465,825 and N-
sulfoalkyl-substituted acrylamides according to U.S.
Patent 4,053,323 are used as d;spers;ng agents ;n cement
slurr;esO Depend;ng on the f;eld of appl;cat;onr agents
~hich reduce water loss, setting retarders or setting
accelerators are added to cement slurr;es, and these must
be compatible with the particular dispersing agent. This
l;m;ts the appl;cabil;ty of the types of d;spersi~g agent.
Thus, for example, if calcium salts are used as setting
accelerators, polyacrylic ac;ds cannot be used 25 the
d;spersing agents.
The effect of partly hydrolyzed polyacrylamides
as agents which reduce water loss is also greatly de-
creased in the presence of calcium chloride. Where the
dispersions are exposed to particularly high stresses,
for example in the case of cement slurr;es and drill;ng
muds based on salt water for very deep hot bores, it is
diff;cult to establish opt;mum properties.
The most diverse non;on;c, anionic and cat;onic
surfactants are also used as dispersing agents.
The invention relates to novel copolymers con-
sisting of 5 - 95% by weight of groups of the formula I
, ~
-~ ~.2~ 7
~1 (I)
- C~l-C~.--
R2
in wh;ch
R~ denotes hydrogen or methyl and
R2 denotes carboxamido, carbomethoxy, cyano or,
preferably, carboxyl,
5 - 95% by we;ght of groups of the formula II, III or IV
~3
I CH
--1H-CH~ OEl ~CH- (III)
lo ~3 K ~ . CH ~S03XO
~ R4
--CH--CH-- (IVj
Co~H-R5- SO ;,e K~B
in which
R3 denotes hydrogen, C1-C6-alkyl or phenyl,
R4 denotes a hydrogen atom or CH3,
R5 denotes C1-C1Q-alkylene and
K+ denotes ammonium, lithium, sodium or potas- .
sium,
and 0 - 5% by weight of groups of the formula V
-CH -C~l-
N-R (V3
b=o
~7
~herein
R6 denotes hydrogen, CH3 or C2H5 and
R7 denotes CH3 or C2H5, or
R6 and R~ together deno~e a propylene group which
forms a pyrrolidone radical together ~ith
the radîcal -N~
O
~ . .
. . . ~ - .
_ 5 ~ 947
~ opolymers which contain up to ZO - 90% of mono-
mers of the ~ormula I and 5 - 50% of the formula II and/
or III or 20 - 70~ of the formula IV are preferred~ The
monomer o~ the formula V is additionally copolymerized
into copolymers used for suspensions of coarser part1cle
s;ze. The molecular weights of the copolymers are between
2,000 and 6 million, preferably between 10,000 and 500,000.
Higher molecular weights are necessary if extreme require-
ments are imposed on the suspension, such as h;gh tempera-
1~ tures and salt contents and low release of water~
The copolymers to be used can be prepared in amanner which is known per se by reaction of the monomers
at temperatures between about -10 and ~80~, preferably
at 20 to 60C~ in the presence of suitable polymer;za~
tion catalysts. The polymeri~at;on is advantageously car-
r;ed out in an aqueous phase, but if appropriate aqueous
solutions of water-miscible organic solvents, such as,
for example methanol, ethanol, tert.-butyl alcohol~ tetra-
hydrofuran or dime~hylFormamide, can also serve as the
polymeri~ation medium. Possible polymerization catalysts
are, ;n part;cular, per-compounds, such as benzoyl per-
oxide, acetyl peroxide, tert.-butyl hydroperoxide or
alkal; metal or ammon;um perox;de-disulfate, or redox
systems, such as N-p-tolylsulfonylmethylcarbamic acid
methyl ester/ammonium peroxide-disulfate.
If appropriate~ it may also be advantageous to
add cocatalysts, such as dibutylamine hydrochlor;de or
traces of copper salts. Compounds such as, for example,
azobisisobutyronitrile, can also be added as polymeri7a-
tion initiators.
On the bas;s of the formulae I, II, III, I~ and
V, the following monomers are preferably used for the
copolymers according to the invention:
1. acrylic acid
2. vinylsulfonic acid
3. me~hallylsulfonic acid
4. acrylamidopropenylmethylenesulfonic acid
5. N-vinyl N-methylacetamide
The copolvmers are obtained as viscous, preferably
,=,
125~39f~7
-- 6 --
aqueous, solut;ons. They can be used in this form~ If
;t is intended to prepare the copolymers in solid form,
the polymer solutions can be subjected to an evaporation
or drying process, for example spray-drying or drum-
drying. For use, it is appropriate for the sulfo groupsin the copolymers to be in the form of the ammonium or
alkal; metal salts.
The copolymers according to the ;nvent;on have a
very effective dispersing action on very small amounts
of solids~ for example calcium carbonate ;n industr;al
cooling c;rculations of only, for example, 10 ppm, or on
cement slurries w;th a very h;gh sol;ds content of up to
80X. The minimum concentrat;on used in the cooling waters
;s 5 ppm, ~hilst ;t can be up to 20% in the cement sLur-
r;es. The h;gh concentrat;ons ;n the cement slurr;esnot;ceably ;mprove the mechan;cal propert;es of the har-
dened cement~ Only the very good d;spersing effect of
the copolymers accord;ng to the ;nvent;on enable the h;gh
concentration ment oned for these polymers to be homo-
geneously distributed in the cement slurry.Examples:
1. D;spers;on of calcium carbonate
A slurry of freshly prec;p;tated calc;um carbo-
nate (100 mgll) in water was used~ 25, 100 and 500 ppm
of a copolymer consist;ng of 10% of me~halLylsulfon;c
acid and 90X of acryl;c acid tK value about 30) were added
to 500 ml of th;s slurry in measur;ng cyl;nders. The
m;xture was shaken and left to stand for about 2 hours
and the supernatant amount of water t250 m3) ~as then
decanted and the sol;ds content therein determined.
Result
Table 1
Amount used dispersed caLc;um carbonate in the
decanted water in % of the starting
concentration
O ppm O
Z5 ppm 22
100 ppm 47
500 ppm 77
~2~ 7
-- 7 --
.,
oo
o
~ o ~ ~ ~ ~ ~o ~
,o
~ U~
r-
-
~o
J~
Q ~-
o
n 0. ~ ~ oo o~
O ~ .-
W ....
C
o C)O
L O
Q N oo 1~ 0 ~ N
~J la ~o
~) >~ _
E O
~ ~ oo ~ U~
.~ ~ ~ r~ O
eL
C U~
O o
W L
o C~
O ~
~ U)
L ~ 1/~ U) 0 In In
a) o
L O 00 C~ 1~ ~ `O 00 O` ~J
O
a) cl: ~ m m
~ . .~
U) ., ~ L L i_ L _ J
~5 _ o
W E E~ E E E ~ E
E ~ ~ _ ~ _ _ ~ 0 t
, U~ ~1 ~ ~ ~ ~
C .. ~ O O ~ o O >~ O O
., ~ ~ + U ~ ~) U U ~:D Q Q
_ ~ E -O ~ ~ o ~ ~I Y- ~
_ E c:5~ ~ ~ ~1 0 ~ O o ~ O ~ O O ~ O ~ O O
., C E E E E E E E E
L U ., W ~I W W W W C5) W W
~a ., _ ~ ~ ~ O ~ O O ~ O -- O O -- O ~ O O
~t) ., 0~ O~
. 0 ~ ~ 0 ~ ~ ~ ~ ' 0
~ m c, ~ m m + m ~ + m + m + ~ m ~ m ~ +
., .
~L2 5~9L~7
- 8 -
Copolymer A: 90% acrylic acid
10% of Na methal~ylsulfonate
Copolymer B: 65% of acrylic acid
35% of acrylamidopropenyl methylenesulfonate
The dr;lling muds were measured at 20C and then
after 15 hours of aging at 200C~ The K value of the
polymers (Fikentscher, Cellulose Chemie 13~ 1932, page 58)
was about 60. The apparent viscos;ty and the liquid
lim;t were measured with a 35 SA FANN viscometer. The
~ater loss accord;ng to API is the filtrat;on rate in
30 minutes according to "API Code 29" wi~h a standardized
filter press at 7 kg/cm2.
3~ Cement slurries
a. Composition. 349 g of water
792 g of cement grade G
Water loss apparent ~iquid limit
API (cm3) viscosity (lbs/100 sq.ft.)
(mPas)
. _
Cement slurry
20 without additive CX3 54 53
Copolymer A from
Example 2 9.0 30 Z
Copolymer 9 from
Example 2 6.5 27
_
The amount of copolymers used is in each case
0~75%. The apparent viscos;ty and liqu;d limit were
determined with a 35 SA FAN~ viscometer,
b. Composition: 349 g of ~later
79Z g of cement grade D
34~
_ 9 ~
Amount Water apparent Liquid limit
used % loss viscosity (lbs/
APIlcm3 (mPas) 100 sq. ft~)
Cement sLurry
5 without additive 44 16
Copolymer s 0~3531.0 30 2
from Example 2 1 4D0 31
3 1.9 34
6 0.~ 38 2
4. Solids suspens;on based on barium sulfate, gypsum, cal-
cium carbonate and carbon.
a) Bar;um sulfate
The solids content is 80% by weight,
the dispersing agent concentration is O~Z5X by
~e;ght
b) Gypsum: CaSO~t.2 H20
The solids content ;s 55~ by weight,
the d;spers;ng agent concentration is 1~0% by
weight
c) Calciurn carbonate
The solids content is 55% by weight,
the dispers;ng agent concentration is 0.25% by
weight
d) Carbon
The solids content is 70% by weight,
the dispersing agent concentration is OD25% by
weight.
All the experiments were carr;ed out with a dis-
persing agent ~hich had a K value of about 60 and had
the following compos;tion:
65% by weight of acrylic acid
30% by weight of acrylamidomethylenepropenylsulfonic
acid
5% by we;ght of methylsulfonic acid
all the monorners were ;n the form of sodiurn salts.
The v;scosity was determined with a Fann VG-35
rotary v;scome~er a~ 6 rpm. The values thereby obtained
. . .
.~ .
~;~5~ 7
are given in the folLo~ing table.
Barium sulfate Gypsum Chalk Carbon
w;~hou~ a dis-
persing agent 31 4Z 19 52
5 ~ith a disper-
s;ng agent2 1~ 3 14
The examples show that the copolymers according
to the invention very effectively disperse both very small
amounts of solids in aqueous solutions and solids in high
concentrations, such as in dr;lling muds and cement slur-
ries. In drilling muds, they are particularly distingu-
ished by their stability to heat and the compatibility
of divalent ions toward polyacrylates.
As a result of their effectiveness in the neutral
range, they are superior to chromium lignosulfona~e and
chrom;um lignite, which are dispersing agents which have
hitherto been widely used for drilL;ng muds and only
operate we~l at h;gher pH va~ues, because high p~1 values
cannot be maintained a~ high temperatures in boreholes
because of reaction of the argillaceous constituents of
the mud with the alkali. In addition, chromium-containing
drill;ng muds are being increasingly subjected to~restric-
tions for environmental protection reasons.
The compounds according to the invention reduce
the viscosity of cement slurries, wh;ch significantly
improves their ease of pumping. ~he water content of the
cement slurries can be kept low, as a result of the good
dispers;ng effect, which r,1eans that the strength of the
hardened cement is increased. In addition, the mechani-
cal properties of the set cement improve as the polymercontent increases. The resu~ts with barium sulfate, gyp-
sum, cha~k and carbon suspensions show how the compounds
according to the inven~ion effectively disperse the most
diverse solids suspensions. Optimum results for the vari-
ous soLids can be achieved by varying the monomer concen-
trations and molecular weights of the compounds according
to the invention.
