Note: Descriptions are shown in the official language in which they were submitted.
~32~3~
METHOD FOR BARIUM SULFATE AND/OR CALCIUM OXALATE SCALE CONTROL
Field of the Invention
The eeesent invention ~e~tain~ to a method of
controlling calcium oxalate and/or ba~ium sulfate ~cale formation
in an aqueous system by using certain copolymers of (meth)acrylic
acid and allyl ether ba~ed monomer~.
- Backqround o the Invention
In the paper~aking proeess, caleiu~ oxalate
scale often form~ on proeesa eguipment during the
bleaching~delignification of pulp by ehlorine, caustie
soda, ehlorine dioxide, hypoehlorite and peroxide. ~sual
areas of scale build-up are on washer drw~ face wires; in
washer vats; in stoek line~ and pu~ps; in filtrate tank~,
lines, and pumps; on extraetion sereens: and in treatment
towers. The for~ation of ealeiu~ oxalate ~eale provides
an eeonomie hardship on ~ills prineipally beeau~e of lost
produetion due to deereased bleaehing~deliqnifieation
effie~eney and eqyip~ent downti~e assoeiated with the
removal of seale.
.~
.
. ~
.. . . ...
,.. ~ ,, . .. =, .. . . .
.. , . , . . .~ .. ..
" 1~26~3~
--2--
One option available to pulp mill~ to attempt to
prevent this scale build-up has been the use of
continuously fed scale control agents. ~istorically,
these additives have included polyphosphates, organic
phosphonic acids, ligno~ulfonates, and various water
~oluble polycarboxylates. ~owever, recent industrial
trends to recycle water in order to reduce blea~h plant
effluent volumes for environmental reasons and the use of
calciw~ carbonate laden paper ~achine white water a~7
bleach plant process water are expected to increase tbe
frequency and severity of calcium osalate scale for~ation.
Moreover, increases in bleach plant hardness and oYalate
levels associated with these trends have caused some of
the convèntional scale control agents to fail because of
their inability to function under condition~ ~hich pro~ote
extensive scale for~ation, na~ely high le~els of calciu~
and,.o,xal.ateO
In the pulp and paper industry, the problem of
bariu~ sulfate deposition has only recently been
addressea. ~he proble~ doe~ not seem to be i~olated to
any particular geographic region, since it has been seen
on ground~ooa ~achinea, fine paper ~achine~ ana unbleached
kraft ~ach~ne~ in all part~ of thc ~nited State-.
Generallr, the deposits ha~e heen found in the ~creens,
cleaner~, fan pu~p, organ tube~, headbox, rectifier rolls,
headbox lip and lice, ana on the Fourarinier foiln.
~he~e depo~it- can lead to for~ation proble~, fiber
~ bundle- or ~t~i~t-~ cooing loo~e and caudng hole~ in the
~heet, and even paper maahine break~ due to crushouts at
- ~ the pres~e~. Deponition àl~o pro~ide~ a favorable
location for ~ulfatc reducing bacteria to fester, leading
e~entuall~ to coFro~ion problem~ and subse~uent
~3~ 132643~
papermaking problems. Where bariu~ sulfate depGsition
problems haYe been especially severe, dollar losses can be
attributed to lost production because of off-seec paper
and cleaning downtimes, labor and mechanîcal cost~ of
cleaning, and shortened equipment life because of corroded
headboxe~. The problem i~ especially acute due to the low
aolubility of the compound in water.
The proble~ of barium sulfate scale formation
has been experienced for ~Rny years in the petroleum
inaustry wherein its formation in drilling case~
surrounaing mud slurries and the like has impeded
petroleum recovery and has caused fouling ana de~osit
formation along drilling i~plements and oil recovery
_line~, ~
SummaeY of the Invention
We have found that calcium oxalate scale and/or barium
sulfate scale may be adequately conteolled by.adding to the
desired aqueous system, such as a eulP and eaeermaking aqueou~
system, fcom about .5 to about 500 eem of a water soluble
~meth)acrylic acid~allyl ether copolymer, based on one
~illion part~ of the aqueou~ ~yste~.
-4- 1326~30
The (~ethlacrylic acidiallyl etber copolymers~
u~eful in accordance with the invention, ha~e the
structure
R~
--IEI-- --ICE~CEII -
c I d
c~
o
~a,
(Xz)
~ . a
wherein E i8 the repeat unit remaining after
polymerization of an~L, ~, ethylenically un~aturated
compound, R~, is ~ or lower ~C~-C.) alkyl, R, i8
~C8.-c~-0)~8, (c8~-cs-o~8~ ~onohydrox~lated C,-C8
C~,
alkyl, monohydroxylated C~-C. alkylene, di- or
polyhydroxy C~-C8 al~yl, dihydroxy or polyhydroxy C~-C8
alkylenc, C~-C8 alkyl, or C~-C~ alkylene, n i~ an integer
of rom 1 to about 20, a i8 0 or 1, X, wheA present, i~ an
anionic radical selected fro~ the group con-i~ting of S0.,
PO~, P0~, and oO0, ~, when prescnt, i~ 8 or hydrogens or a
water ~olublc cation or cat}ons, Z being chosen to
counterbalance thc ~alence o X, X,Z co~bined ~ay also . '.
denote an a ine functionality of the for~ula
. . .
: . ~
132643~
s~z 003 P2A3 -5--
- ~N - F,
F2
wheeein F~ F. and F. are in~ependently ~elected rom ~,
a~d C~-~ alkyl, C~-C5..hydroxy-sl~stituted or carboxy-
substituted alkyl, the ~olar ratio of repeat units c:dbeing from a~out 30:1 to about 1:20.
- In accordance with the method, from O.l to 500
part~ of the (meth)acrylic acid~allyl ether copolymer are
admitted to the desired agueous system, ba~ed upon one
million parts o the aqueous system.
Pcior Art
The water ~oluble or water diseersible copolymers used
in accordance with the invention to control calcium oxalate and/o~
barium sulfate scale are not new. For instance,
~.S. Patent ~,500,693 ~Takehara et al) di6closes water
soluble copolymer~ ha~ing an acrylic acid or methacrylic
acid repeat unit ~hich i~ co-polymeri~ed ~ith certain
allyl ether ~onomer~ e polymers di~clo~ed in
accordance ~itb Takehara et al are useful calciu~
carbonate inhibitors and ~ay also be used a~ pigment
dispersants.
.S. Patent ~,469,615 ~ssuruoka et al) discloses
~ater treat~ent co~positions co~prising a ~ater soluble
copolymer having, a~ the co~ponents, one repeat unit
formed fro~ an addition reaction product o a glycidyl
ether or glrcidyl-e~ter and an ~, B ethylenically
unsaturated carbo~yl~c acid. She ca-~ono~ee ~ay comprise
.
- 132~`~3~
-6-
any vinyl monomer. The copolymers are reported a~ being
useful aff corrosion inhibition agents in ~ater system~.
Japanese Patent Publication S~056-155692,
~Method o Collecting Dust~ discloses use of acrylic
acid/polyethylene glycol monoallylether copolymers which
are utilized to treat the recirculating water in an
aqueous dust collectinq ~ystem. In this disclosure, the
number o woles of etho~ylation i8 taught as being rom 5
to 100. If the nu~ber is le~s than 5, the scale control
and di~persant efficacie~ are insufficient.
~ offenlegungs~chrift 25 22 637 discloses varied
acrylic acid type copolymer~ which may he utilized to
stabilize haraness in water systems.
European Publication 01~2929 aisclose~ water
treat~ent poly~ers which are in many cases coextensive
~ith those herein aisclo~ed. The poly~ers are utilized to
inhibit calciu~ phosphate and calciu~ phosEbonate in
aqueou~ ~yste ~. They also function to provide a
passivated oxide fil~ along treated metal ~urfaces when
they arc used con~ointly with a water soluble
orthophosphate source.
.S. Patents 4,659,481 IChen) and ~,732,698
~Chen) disclose the utili~ation of certain ~meth)acrylic
acid~allyl ether copolymer~ that ~ay be utilized to
provide the elu~ive passive oxidc fil~ along ~ater system
metallurgy ~hen used con~ointly ~ith an orthophosphate ion
source. ~bst ~pecifically preferred i8 utilizat~on of an
acrylic acia~2-hydro~yeropylsulfonate ether copolymer.
, . .. . .
1326~3~
~ .S. Patents 4,659,482 (Chen) and 4,717,499
(Chen) diselose use of (meth)acrylic acid/allyl ether
copolymers to simultaneously inhibit corrosion and calcium
carbonate depo~ition in water systems under elevated p~
~ ~i.e., 7.5-9.0) and calciu~ carbonate supersaturation
conditions.
- ~.S. Patent 4,701,262 (Chen) discloses the
utilization of acrylic acid/allylhydroxyalkyl ether
copolymers in combination with 2-pho~phonobutane 1,2,4-
tricarboxylic acid to inhibit calcium sulfate and calcium
carbonate ~cale.
U.S. P2tent 4,759,851, discloses utilization
of acrylic acid/allylhydroxyalkyl ether copolymers to
control calcium phosphonate scale in water'sy~ems.
a.s. Patents 4,659,480 (Chen et al) and
4,708,815 (Chen et al) disclose utilization of certain
acrylic acid/allyl alkylene phospbite ether copolymers in
water,~rea,tment systems.
U.S. Patent 4,560,481 (~ollander) discloses
utilization of acrylic acia~allylhydroxypropylsulfonate
ether copolymers to control iron-ba~ed fouling in cooling
water system~. ~.S. Patent 4,671,880 Wisener et al
discloses use of such polymers to control alum carryover
" from clarifiers, etc.
~.S. Patent 4,693,829 ~Boffardi) disc10ses
utilization of acrylic acid~2-acrylamido-2-methyl propane
sulfonic acid copolymers for barium sulfate inhibition.
~owever~ the disclosed copolymers contain amide'lin~ages
which are not as thermally and hydrolytically stable as
the copoly~ers of the present invention which contain
ether linkageJ.
Proce~ses for controlling calcium oxalate scale
over a ~ide p~ range are disclose~d in ~.S. P~ent
4,575,425 (Boffardi et al). In accordance with the
discloJure, calciu~ oxalate in agueous systems i8
,
A
~6~
-
controlied by use of (al a water ~oluble phosphate,
pho~phonate or pho~phinate and ~b) an anionic water
soluble polyelestrolyte As to the anionic water soluble
polyelectrolytes which ~ay be utilized the preferred
polyelectrolytes are poly~ers o unsaturated carboxylic
acids or salts thereof As example~, acrylic acid,
methacrylic acid, copolymers of acrylic acid and
methacrylic acid, copolymers of ~meth)acrylic acid and 2-
acryla~ido-2-~ethyl propane sulonic acid, copolymers of
acrylic acid and 2-hydrosyproprl acrylate, and copolymers
of metha~rylic acid and 2-hydroxypropyl acrylate are
mentioned Ater reading the '425 disclosure, one s~illed
in the art would not expect that allyl deri~ed ~onomers
would be effecti~e a~ calciu~ o~alate dbpo~it control
agents
Other pa~ents which may be of intere~t to the present
invention include U.S. Patent 3,549,548 (Newman) U.S. Patent
3,992,31~ (Gaupp et al); U.S. Patent 4,029,577 (Godlewski et al);
4,303,568 (May et al) 4,324,684 (Geiger et al).
Chcm Abstract- 99:58708X, 'Scale Inhibitor~ for Cooling
~ater Srstea', al~o appears to be of interc~t as the
discloJed ~ale inhibitors comprise an acrylic or
methacr~lic acid copolymer wherein the second ~onomer i8
formea froo a polyalkyle~e glycol monoallyl ether.
Chem ~b-Sract~ 98 203736r, 'Additives or Dust
Scrubbi~g Liguor', discloses ~tilization o a copoly~er of
polyalkylene glycol ~ono~llyl ether and methacrrlic acid.
. :. .
1326430
g
Detailed DescriPtion of the Preferred E~bodi-en~
In accordance with the invention, it has been di~covered
that certain water ~oluble copolymer~, as ~hown in Formula I
hereinafter, are effective in conteolling the formation of calcium
oxalate andior barium sulfate deeosits in vaeious water sy~tems.
The poly~ers ~omerise repeat units composed of an~ ethylenically
unsaturated compound and an allyl alkylene ether based compound.
The (meth)acrylic acid/allyl ether polymer~ u~eful in accordance
with the invention have the structure
R~
-IE } { C~l-C~I
c , I d
CQ,
O ~ FORM~LA I
R~
~XZ)
~herein E i~ thc repeat unit remaining ater
poly~eriration of an~,8, ethylenically unsaturated
co~pound, R~ is ~ or lower ~C~-C~) alkyl, ~ C~,-
C~,-O)~ c~,-C~O)_~, c~, monohydro~ylatea C~-C~ alkyl,
CE~
~onohydro~ylated C~-C~ alkylene, di- or polyhydro~y C~-
C. alk~l, C~ ~ alkylene, n i~ an integer of froa 1 to
about 20, a i~ 0 or f, i, w~en present, i~ an anionia
radical ~clected froa the group consirting of SO~, PO,,
.
. . . .
1~2~3~
--~o
Po~, and coO, Z, when present, i8 8 or hydrogens or a
water soluble cation or aation~, ~ being chosen to
counterbalance the ~alence of X, X,Z combined may also
denote an amine functionality of the formula
F~
F,
F~
wherein Fl, F2. F3 are independently 6elected from H, and
Cl-C5 alkyl, Cl-C5 hydroxy-substituted or
carboxy-substituted alkyl, the molar ratio of repeat unit~ c:d
being from about 30:1 to about 1:20.
E in the above for~ula may, for instance,
comerise the repeat unit obtained after polymerization of
ano~ ethylenically unsaturated ~onomer, preferably a
carboxylio acid, amide form thereof, or lower alkyl ~C~-
C,~ e~ter or hydroxylated lower alkyl ~C,-C~ ester of
such carboxylic acid. Exemplary comeounds encompassed by
E inciude, but are not restricted to the repcat unit
for~ed by polymeri~ation of acrylic acid, rethacrylic
aci~, acrylamide, maleic acid or anhydride, fu~aric acid,
itaconic acid, 2-hydroxypropy~ acrylate, atyrene ~ulfonic
acid, and 2-acryla~ido-2-methyl proeane-sulfonic acid and
the like. Water soluble salt for~ of ~hese acid- are
also within the purview of the in~ention.
She second repeat unit in Fonmula I may include,
a~ exe~plary repeat unit-, repeats unit~ for~ed fro~
mono era ~uch a~ l-allyloxy-2-propanol, l-allyloxypropane
2,3-diol ~glyceryl allyl ether), polyethylene glycol allyl
cther, polypropyleneglycol allyl ~ther, l-allyloxypropane
: . .
132~
2-hydroYy-~-sulfonic acid and water soluble salt-forms
thereof.
The ~olar ratio c:d o the repeat units may fall
withi~ the range of 30:1 to 1:20, ~ore de~irably within
lS:l to 1:10.
The number average ~olecular weight of the water
~oluble copolymers of Formula I i8 not critical and may
fall within the Mn range of from about 1,000 to l,OOO,OOG,
desirably, l,000 to 30,000, and most desirably 1,500 to
25,000. The ~ey criterion is that the copolymer be water
, solu})le.
~ he polymers may be prepared by conventional
techniques such as those e~pressea in U.S. Patent
4,659,481 (Chen) and 4,708,815 ~Chen et ?l), both being of
common assignment herewith,
.. It is noted that in the case in
which XZ in repeat unit td) i8 a~ auine functionality, the.
mono~er can be prepared in accordance ~ith the followinq
mechanislo:
C~, = C - C~ - O - C~y - C~-~C~, ~ ,N - ~ ~r
C~, --Cll - C~. ~ O - CE~, - CE~O~ - CE~
F~
For ~ak~ of brevity, suffice it here to state that these
conventional techniques include frce raaical ~so1ution,
precipitation or e~ulsion poly~erization technigye#.- - -
Conventional poly~eri~ation initiators ~uch a#
: ... ., . - :
1i~2643~
persulfates, peroxide~, W light, etc. may be used.
Chain transfer agent~ such as alcohols ~preEerably
isopropanol), amine or mercapto compounds ~ay be used to
regulate the ~olecular weight of the poly~er. ~he
resulting.polymer ~ay be isolated by well known technigue~
including precipitation, etc. If polymerized in water,
the polymer ~ay ~imply be u~ed in it8 aqueous ~olution.
The polymers presently preferred for use are
acrylic acidt2-hydroYypropyl sulfonate ether polymers of
the formula:
' ~' EI
I _ I I I
~ c
El C = O ~ C~, '
OM O Foemula II
c~,
. ~
- ~C - 08
c~. .
So~M
~herein M i- ~ or a water 801uble cation, the ~olar ratio
c:d being about 15:1 to 1:10. The optL~al nu~ber average
molecular ~e~gbt ~Mn~ of the For~ula II copolymer i~ OA
the order of 1,000 to 30,000.
~, , Superior perfor~ance han al80 be howA by
acrylic acid~l-allylosy-2-peopanol ~AOP) copolymers
~ illu~trated by the following Formula III:
.
. -
1326~
- 1~
C ~ I ~d
E~ C = O ~ CE~ ,
OM O Formula III-
CE~
C~
M is as defined in Formula II, the molar ratio of c d i8
from about 15 1 to 1 10 and the molecular ~eight Mn of the
copolymer i~ preferably about 1,000-30,000.
Another qroup of poly~ers showing particular
promise are the acrylic acid~polyethylene glycol allyl
; ether polymer- baving the ~tructure
~ C - C ~ ~ ~ I ~d
.'. ~ C = 0 11 C
OM. O
- C~, Foraula IV
C~
~ t'n
..
wherein n i~ roo 1 to about 20, preerably 1 to 15, c:d
- 1326430
i8 fro~ 15:1 to l:lO, and wherein the preferred Mn
molecular weight i~ about 1,000-30,000.
The polymers (Formulae I-IV) should be added to the
aqueous ~ystem in which ~alcium oxalate and/o~ barium sulfate
de~ofiit control activity is desired. in an amount effective for
the purpo~e~ This amount will vary depending upon the
particular syste~ for which treat~ent i8 desired and will
be influenced by factors such as: hardness, p~,
temperature, water quality and the respective
- concentrations in the water of the potential scale and
deposit for~ing species~ For the most part, the polymer~
~ill be effective when used at levels of about 0.1-500
parts per million parts of water, and preferably from
about 1.0 to lO0 parts per million of water contained in
the aqueou~ system to be treated. The polymers may be ~
added directly into the desired water system in a fixed
guantity and in the state of an aqueous solution,
continuoudy or inten~ittently.
~ he p~ly~ers of the present invention are not
limited to use in any specific category of water system.
For in~tance, in addition to paper and pulp processing,
the eolymers may al60 be effectively utilized in other water
systems wherein calcium oxalate and/or barium sulfate scale
control is important.
In an especially ~ignificant aspect of the
in~ention, tbe calciu~ oxalate scale control agents herein
di~clo~ed exhibit tbe characteristic of being highly
calciu~ tolerant. By this, ~e ~ean, that unli~e some
other kno~n anionic polyelectrolytes, the ~meth)acrylic
~2`1~
-15-
acid/allyl ether copolymers of the pre~ent invention are
able to perform their intended caloiwm oxalate scale
control function even in those waters having a high
calciu~ ion content ~i.e., greater than about 300-400 pp~
as Ca~-). In contrast, some other anionic polymers
selectively eeact with the high levels of ~alcium in the
system water and are then unavailable to perform their
intended scale control function.
The invention will now be further de~cribed with
reference to a number of specific examples which are to be
regarded solely as illustrative, and not as restricting
the scope of the in~ention.
E~tamples
The following e~amples deal with the
preparation of the copolymers which have prove~n
efficaciou~ in cont~olling calcium oxalate and/or barium sulfate
~cale~formation.
E~ample~ 1-6: Preparation of acrylic acid ~AA) allyl
hydroxyproeylsulfoAate ethcr, sodium Jalt
~A8PS~ )
Shcse poly~ers were all prepared in substantial
confor ity to the procedure given in Examples 1 and 6 of
~.S. Patent ~,659,481, with ~a~or exception~ being the
relative ratio~ of reactants used and the ~olecular
weight~ of the resulting poly~ers. EYample 1 of the '481
patent i~ repéated hereinbelow.
~ A~auitable reactloA flask was equipped with a
- mechanical agitator, a thenDo~eter, a reflus condenser, a
nitrogen inlet and two addition iAlets for the initiator
... .
.
- 1326430
- - -16
and monomer solutions. The fla~k was charged with 200g
of deionized water and 269 of isopropanol. The resulting
solution was then heated to reflux under a nitrogen
blan~et 72~ of acrylic acid ~ mole) and 1369 of l~propane
~ sulfonic acid, 2-hydro~y-3-~2-propenyl o~y) mono sodium
salt IA~PSEl (40%, 0.25 mole) were miYed in a separate
flask 80 a8 to provide a mixed monomer solution. ~he
mixed monomer 801ution was then transferred to an addition
funnel . An initiator solution containing 27.3% of ~odium
- persulfate in deionized water was prepared separately and
sparged with nitrogen. The initiator sclution (20 ml) was
then added to the reaction flask along with the mi~ed
monomer ~olution over a period of 2 hours. After this
addition, the resulting ~ixture was heated for 2 more
hours at 85C and ~ub~equently, 66.59 of the
isoproeanolJwater ~olution was stripped off. She reaction
misture ~as then cooled to less than 40C and 60g of 50%
aaustic ~olution was then added.
EYa~ple 7 : Preparation of Acrylic Acid (AA)~I-
Allylo~y-2-propanol ~AOP) Copolymer of
about 3~1 mole ratio AAfAOP.
A ~uitable reaction flask was equipped with a
mechanical agitator, a thermo~eter, a reflu~ condenser, a
nitrogen inlet and two addition inlets for the initiator
and monomer solution~. ~he flask was charged with 2209 of
deionized ~ater a~d 35g of isopropanol. Thc re~ulting
aolutioA ~a- then heated to reflux under a nitrogen
blan~et. In a ~eparate ~esJel, 43.29 ~0.6 mole) of
acrylic acid aAd 23.29 (94~ pure, 0.19 mole) of 1-
..
1326~
-17-
allyloxy-2-propanol were miYed 80 as to provide a mîxed
mono~er ~olution. ~he ~ixed mono~er solution was then
transferred to an addition funnel. An initiator ~olution
containing 24.4~ o sodiu~ persulate in deionized water
was prepared separately and sparged with nitrogen. The
initiator ~olution ~1791 was then added to the reaction
flask along with the ~ixed mono~er 801ution over a period
of two hours. After this addition, so~e additional
persulfate solution wa~ added to the reaction mixture for
',''5 one more hour at 85C and, subsequently, lO9.0g of the
i~opropanol/water 801ution were stripped off. The
reaction mixture was then cooled to lower than 40C and 34g
of 50% caustie solution was added.
The structure of the resulting polymer was
verified by Carbon 13 NMR. The polymer solution, after
being diluted to 2~.8% solids with water, had a Broo~ield
visco~ity of 1~.7 cp~ at 25C. It wa~ rtable ~olution with
a slightlr yello~ color. ~he ~olecular ~eight ~as IMn)
was ~,000 as deten~ined by aP
E~ample 8:
~ tilizing the apparatus and procedure described
in E~ample 7, ~3.29 of acrylic acid ~0.6 ~ole) and 129 of
AOP 19~%, 0.097 mole) were used for copolymerization. The
resulting poly~er solution, after being dilutea to 23.8%
solids had a Brookfield ~iscosity of 15.7 cps lat 25C).
~326430
18-
Exa~ple 9: AAJpolyethyleneglycol (PEG) Allyl Ether
Copolymer
~ tilizing both aeearatus and procedure similar
to that de~cribed in Exa~ple 6, 120g of deionized watcr
and-2~q of polyethylene~lycol allyl ether Iwith ~ moles of
ethylene glycol) wese charged to a reaction flask. The
solution was then heated to 90C under a nitrogen blanket.
21.69 of acrylic acid were then added to the reaction
flask along with an initiator solution co~pri8ing ~odiu~
persulfate o~er a period of 1 hour. The reaction ~i~ture
was heated for 3 ~ore hours and was subsequently cooled
to lower than ~OC whil.e 169 of 50% caustic solution were
added. C13 NMR showed that'no residual monomer was
present.
The re~ultinq polymer solution~ after being
diluted to 25~ ~ith-~ater, had a Brookfield viscosity of
- 2~-cp~ ~at 25C). ~he ~olecular ~eight IMn) ~a- 7,500 a~
deter~ined by GPC.
Ex;~ple lOs AA/PEG Allyl Ether
~ til~zing the apearatus and procedure de~cribed
in 8~a~plc 6, 21~69 of acrylic acid (0.3 ~ole) and ~8.1g
of polyethyleneglycol al'lyl ether ~containing 9.6 ~oles of
ethyleneglycol~ ~ere used for copolymeri~ation. The
resulting eoly~er solution, after being diluted to 25.3
had a Brookfleld vi~co~ity of 22.6 Cp8 ~at 25C~. The
~olecular ~eight ~a- 5,100 a~ ~easured by GPC.
~ aqele~ 18 ,~ere prepared by the s~ilar
, ~ethods as des,cr~bed above., '
Table I hereinbelow ~resents a ~umma~y of the
- phy~ical propertie- of the copolyme~s. `"
- - lg 132~3~
Table I
Copolymer Properties
Viscosity, cps
Brookfield #
Copolymer CompositionMole Ratio 25~, 25C Mn
Example 1 AA/AHPS 3:1 15.8 6,900
Example 2 AA/AHPS 3:1 14.9 5,100
Example 3 AA/AHPS 6:1 23.0 7,500
Example 4 AA/AHPS 6:1 15.2 4,500
Example 5 AA/AHPS 6:1 13.6 2,610
Example 6 AA/AHPS15:1 18.8 6,800
Example 7 AA/AOP 3:1 14.7 4,000
Example 8 AA/AOP 6:1 15.7 4,000
Example 9 AA/PEG AE*3:1 24.0 7,500
Example 10 AA/PEG AE** 3:1 22.6 5,100
Example 11 MAA/PEG AE** 6:1 132.0(30%)
Example 12 MAA/PEG AE* 6:1 122.0(30%)
Example 13 AA/GAE 3:1 18.6
Example 14 AA/GAE 6:1 22.5
Example 15 AA/AMPS4.3:1 12.7
Example 16 AA/AMPS15:1 14.4 5,200
Example 17 AA/AMPSE/AMPS 6:1:1 18.0 2,980
Example 18 AA/HPA 15:1 18.8 5,500
AA = acrylic acid
AHPS = l-allyloxypropane-2-hydroxypropane-3-sulfonic acid sodium
salt
AOP = l-alloxy-2-propanol
MAA = methacrylic acid
PEG AE = polyethyleneglycol allyl ether
*Q9.6 moles of ethyleneglycol
**@ 4 moles of ethyleneglycol
GAE = glyceryl allyl ether
AMPS = 2-acrylamido-2-methylpropane sulfonic acid
HPA = 2-hydroxypropyl acrylate
#Mn. number average molecular weight, was measured by the gel
permeation chromatography (GPC) method using Toyo Soda G-2000 SW or
G-4000 SW column calibrated with polystyrene sulfonate standards
in sodium nitrate solution. Molecular weight results from GPC
depend on the type of column, condition and standards used.
Example 15, 16 and 18 are disclosed in U.S. Patent 4,575,425. They
are used herein to serve as a basis for comparison.
~r
1~2~3~
-20-
In addition to test~ run with the copolymers
reported in ExaMples 1-18 hereof~ co~parative test~ were
al80 perfor~ed u~ing mRny conventional, ~ell-known, water
treatment agents. These are identified in the following
~Control Table~.
Control Table
CONTROL DESCRIPTION
A - sodium tripolyphosphate 8TPP
8 - ~odium hexametaphosphate
c - 2-phosphonobutane-1,2,~-tricarbo~ylic acid
D - a~inotris(methylene phosphonic acid) = AMP
~ - ~ulfonated lignin
F - polyacrylic acid
G - copolymer of sulfonated strrene ~aleic
anhydride ~AROO Chemical Co.)
- copolymer malei~ anhydride~methylvinyl ether
I - ~ulfonated napthalene for~aldehyde
conden~ate
J - copolymer of ~ulfonated ~tyrene~maleic
anhydride (National Starcb Co.)
~ - ~tyrene~maleic anhydride
Efficac~ Testina
Calcium Oxalate Control Te~t-
The dcpo~it control te~ting was basea on cry~tal
modific,ation. Oxalate, depo~it control age~t, and calciu~
were respcct~vel~ adaed to a ~o~n volume of.deionized
~ter prehcated to 60C. The~ p~ of the te~t 80iution ~as
checked~aa~u-ted follo~ing the addition of the de~o~it.
.. . . . .
- ~26~30
- -21-
control agent; the p~ of the calciu~ sto~k solution was
pread~usted to the appropriate value prior to addition.
The saople was then incubated at 60~C for one hour. At
that time, the percent transmittance of the supernatant
~olution was ~easured withoS disturbing any settled
precipitate. ~he ~ percent trans~ittance wa~ ~etermined
at a wavelength of dlS nano~eter~.
During incubation un~odified calcium oYalate
crystals settled guickly: the solution was clear and
yielded a high percent tran~mittance measurement.
Crystals ~odified by the adsorption o anionic deposit
control agent~ were smaller and more negatively charged
and remained suspended for long period~ of tL~e; in this
case the test ~olution was cloudy and yielded a lower
percent transmittaAce measurement.
The percent aeposit control ~a- calculated from
the e~pres~ioa.
%C - %T~untreated) - ~T~treated) ~ 100
Test Condition-: 60-C, I hour incubation time
~ 00 pp~ Ca~ae Ca~'~, 300 pp~ o~alate,
10-100 pp~ deQosit control agent, p~ 7-10
~ e~ultr are ~eporte~ in Table~ ~IA and II8.
. . .
1~26~31~
--22--
Table IIA
Calcium O~alate Control Te~t
_ _ _ _ _
( 60C; 10 p~ actiYe)
~ Control~
Examl?le Additive p~ 7 p0 10
PSE 91.8 9~.3
2 AA~ABPSE 92 . 8 g2 .1
3 AA/A~IPSE 85.8 - 90.6
4 AA/A~PSE 90-9 93.0
S AA/A~PSE 78 . 6 88 . 7
6 AA~A~PSE 46.~ 48.4
7 M~AOP 82.8 70.9
8 AA~AOP 70-6 71-4
9 AA~PEG AE 75 . 0 77 . 8
MJPEG AE 80-1 79.6
11 MAA~PEG AE 5~. 9 53 . 8
12 MAA~PEG AE 52.8 ~7.7
13 M~ 35-6 30.9
14 AA~GAE 67-7 63.0
AAJAMPS gO.1- 92.0 .
16 AA~AttP8 76-2 68-2
17 ~ M~ABPSEJAMPg 90.9 -95.4
18 AA~E~PA 6~.3 87.
A 0 2.2
B 22.8 15.5
C ~ 5.1 2.0
O O
E 5.6 3.1
F 4.8 25.4
G 1.0 5.3
B 0 0
0 1.1
J ~.C 5-2
1~ 7.5 3.7
. . A lo~er te~peratur~ tert at 25-C i8 reE?o~td il~ ~able IIB. .
:. .
~3;~
- 23 -
Table IIB
Calciu~ Oxalate Control ~est
~25Ç; 10 ppm aati~te)
~ Control
ExamPle Additive p~ 7 P~ 10
1 AA~A~PSE 9~ .8 85.7
2 AA~A~PSE 90.8 96.1
8 M/A~PSE 9~. . 693 . 2
4 AA/AEIPSE 85.5 88.1
S AA/A~PSE 75. o 73 3
6 AA/A~PSE 66.7 63.6
7 AA/AOP 8~ .8 81.0
8 AA/AOP 85.0 90.4
- ~ 9 AA/PEG AE 88.9 90.5
U~/PEG AE 9~.. 4 85.0
1~ . MAA/PE~ AE 93.0 . 81.8
12 MAA/PEG AE 93.0 90.0
13 M/GAE 92.2 81.
1~ M/GAE 88.3 90.3
AA/AM`PS - 85.7 8~.6
16 AAJAMPS 88.9 87.2
17 AA~A~PSE~AMPS 85.7 88.6
18 AA/EPA 93.3 82.1
A 0 ~0.2
B 0 0
C __ __
D __ __
E ~1.7 59.5
" F 59.~ 7~,8
G 92.1 83.9
86.S 0
I 0 22.8
J 76.2 88.6
82.9 2.2
Fro~ the results reported in Tables IIA and IIB,
it can be seen th t the poly~e~- in accoraan¢e ~ith the
- :.
132~3~
-24-
inYention are ~uperior to the tested comparative water
treat~ent agent~ in inhibiting calciu~ oxalate ~cale
formation, especially at elevated temperature which i~ a
more common fi~ld condition. Copolymers of E~amples 15,
16, and 18 a~ disclosed in the prior art Boffardi et al
patent are al~o efficacious under the~e conditions.
Bowever, they contain either amide or ester linkages which
are not as thenmally and hydrolytical1y stable as the
copolymers in this invention which contain ether
linkages.
The Controls and Examples previously describea
were also exa~ined at 60-400 pp~ calciu~ and 100 pp~
o~alatc. The ~ control in this case wa~ de~ermined by
measuring the filtered residual calcium levels since there
is insuficient a~ount of crystal to be obser~ed by liqht
trans~ittancc. Hith a 25 ppm acti~e of copolymer of
E~a ple 3 proviaed ~2.~ and ~8.9% control, respectively.
~nder the identical condition~, duplicate te~ts ~ith a 25
pp~ acti~e of Control B material providcd 95t and ~S.6
control. ~he incon-istency in this data preclude any
conclusive co pari~o~c and the data are deemed to be
irrele~ant in thi~ testinq conditions. In contra~t, the
resQlt~ cho~ in Ta~lea IIA and II8 are reproducible.
Calciu~ Tolerance Test
Calciu~ tolerance te~ting wa~ basea on the
appearance of turbidity or a deposit ~hen a deposlt
control agent wa- aaded to a known concentration of
calcium and incuba~ed at 60C for one hour. A deposit
.
.
i32~3~
-25-
control agent was consiaered intolerant o calcium if it~
associated te~t solution was turbid or contained a
sedi~ent at the end of the incubation period. ~esting
results of the polymers in this in~ention and tbe
co~parative ~2teri~1 are sho~n in Table III.
Test conditions: Te~p. = 60C, I hour incubation
time, 400 pp~ Ca~' (as Ca ') 10-lO0 ppm deposit control
agent, p~=7-10.
.,
,
~3~2~43~
- --26--
Table III
C21ci~ Tolerance Test
.
~60C; 100 pplo active~
Final Solution Appearance
ExamPle _ P~ 7 P~ 10
C C
2 C C
3 - C C
4 C C
C C
6 C D
7 C C
8 C C
9 C C
- 10 C
11 ' C C
12 . C C
13 C S
1~ C S
C C
16 - C T
17 C C
18 C C
A C D
B C T,D
C . , C D
D D D
E C C
F .~ T D
G S T
C D
Ç C
J~ C C
C ~ Clear
~ = Surb~d ,~
D e Depo~t
~ =. .
26~30
-27-
Addi~ional te~t was also done at 10 ppm activ~
for t~e copolymer~ of ~xamples 6, 13, and 1~. At p~ 7 and
10, they are all clear.
Discus~ion of Results_ana OPinion ~hereon
~ ~hown in the Tables IIA and IIB, it i8 clear
that the poly~ers in the instant inventio~ control the
gro~th of calciu~ oxalate cry8tal8 ~ore effectively than
~any of the conventional depo~it control agent~. In
- paeticular, the poly~ers used in accordance with the
invention perfor~ ~uch more effectively than the acrylic
acid homopolrmer, the ~aleic anhydride copolymers, and the
sulfonatea copoly~ers. ~n addition, the data in Table III
prove that the turbidity ~hich developed durinq the
deeosit control test involvinq the acrylic acid~allyl
ether eolymers, i~ due to calciu~ oxalate crystal gro~th
~odification, and not ~;~ply due to calciu intolerance.
In co0eariso~, se~eral of the tc8toa co~trol ~aterial~ are
calciu i~toleeant. ~hesefore, the methoa~ herein
aisclosed #ol~e t~e proble of coAtrolling calciu~ oxalate
Eor~atio~ espe¢ially iQ aqueou~ sxste~s in ~hich high
calciu~ andJor o~alate levels precl~de the use of ~ore
,co~eational agent-.
- 1~236~
-28-
Examples L9 and 20
Copoly~ees particularly useful in ac~ordance with th~
inventio~ for the inhibition of barium sulfate scale fo~mation
were also pee~ared i~ accocda~ce with the procedure given in U.S.
Patent 4,659~81 (CheQ). Copolymer A however is the copolymec o~
Example ? S~ecifically, in each instance of polymer preearation,
the following peocedure was used. A eeactio~ flask was equipped
with a mechanical agitator, a thermo~eter, a reflux co~densec, a
~itrogen inlet and two addition inlets for the initiator and
~onomer solutions. The flask was charged with the reguired amount
of deio~ized water, isoeropanol, and AHPSE (allyl hydroxy pro~yl
~ulfonate ether, 1 - allyloxy propane 2-hyd~oxy-3-sulfonic a~id,
60aium ~alt) ~onomee. The resulting ~olution wa~ then heated to
85-C under a nitroge~ blanket.
An initiator ~olution coAtaining ~odium
persulEate in deionized water was seEura~^~r preEared and
then sparged ~ith n~itrogen. ~he initiator solution uas
theA added to the reaction flas~ along with acrylic acid
o~er a perioa of three kour~. Ater this additio~, the
resulting ~isture uas heated for one ~ore ~our at 85-C and
~ubsegue~tl~ the i~opropanol~ater ~olutio~ ~as stripEed
off. She reaction d xture was then ccoled and neutralized
by cau~tic addition. Structures of the re~ulting poly~ers
ere ~erifiea by ~arbon 13 NMR.
Sable rYhercinbel~ present~ a s~marr o the
pSy~ical properties o the co~oly~er~.
.. . . . . . .
- 1~2643~
g
Tablc nt - Pol~mer ProPertie~
Monomer Ratio _ Vi~c08ity
Example PolYmer AA~A~PsE % 8O1 ia8 Mn CP8 25~C
2 A 3:1 24.6 5,100 14.9
19 B 6:1 29.5 8,S00 28.0
~e 25~ solids)
. C 6:1 30.7 e~ooo 28-5
~e 25% solids)
AA = acrylic acia
~PSE = allyl hydrosypropyl ~ulonate ether
Mn, nu~ber a~eraqe molecular ~ei~ht, ~as measurea by gel
per~eation chro~atography ~G~C~ method usiog ~oyo S~da G
2000 S~ or G-4000 SW colu~n calibrated ~ith Eolystyrene
~ulfonate ~tandard~ i~ 80diw~ nitrate ~olution. Molecular
~eight re~ults fro~ GPC depena on the type o column,
condition and,~tandaral~ u~ed.
.
--30--
132~3~
Efficac~ Testinn
Bariu~ 8ulfate Inhibition - ~est Procedure
2 pplo E~a~a
1000 pp~ SO4,-
~p~ 5.5
60C
To lO0 g~ total test ~olution are added Ba~', polymer, and
S0.~~. ~he p~ of the test 801ution i8 aa~ustea to 5.5
after the eolymer addition. She p~ of the S0,~' stock
solution i8 preadju~ted to S.S prior to its addition to
the tests. Tbe test solutions are heated at 60C for l
hour and then cooled at roo~ temperature for 20 minutes.
Next cac~ ~olution i~ iltered through a clea~ 0.2 ~icron
pore~ e filter, acidified with BCl to a final p~ of 2
and analyzed for soluble bariu~. The ~ inhibition is
deter~ined by the expressions
~ Ba (treated~ - Ba (co~trol)
% Inhibition ~ 100 ~ 8a ~theoretical) - Ba (control)
~ax.
Bere, ~a~' (treated) i8 the ppm soluble 8a~' resulting
ron a qiveQ polyoer dosage, ~a~' Icontrol) i~ the ppm
Ba~' resultiQg fro~ no treat~ent, and Ba~' (theoretical
~a~) i8 the ~oluble 8a~i intioduced into the test fro~ the
:
-3~ 32~3~
sa~ stock 801ution- In this experiment, sa~'
~theoretical mRx) i8 2 ppm. Typically, Ba~' (control) i~
approxi~ately .3 pp~.
~ esulte of the barium sulfate inhibition tests
are reported in Table Y .
TableV
sarium Sulfate Inhibition
~Result~ Expressed as Percent Inhibition)
SSM~ SSMA+
Pol~rmer A Pol~,nDer BPol~rmer C~000 3000
-
5 Pe~*23.6 25.5 24.8 0 0
2J.. 9 22.~, - 24.2 0 0
10 ppQ~21.2 2~.2 29.1 0 0
31.2 32.1 26.~ 0 0
20 pp~ 51.5 27.9 29.1 0 0
~,8.5 36.~ -27.3 0 0
pp~ on an actives basi~
coo~erciallr avallable tyrene sulfonate~aleic
anbydeide copoly~er~
In separate tests, the results were rouqhly
co parable ~ith ~ell-knonA agents such as polyaceylic
acid, but were ~o e~hat in~erior to po1yphosphate.
~o~ever, polyphosphate i8 not as hydrolytically stable as
the polyner~ of the prese~t inveAtioA wh~ch contain ether
lin~aqe~.
While thi~ iAveAtioA has been de~cribed ~ith
respect to particular c~bodi~eA~ thereof, it i8 apparent
that numerou~ otber for~ aAa ~odîfication~ oE this
iA~ tioA dll be obvious to thosë skil~cd i;~ the art.
She a~e~ded clai-~ ~d th~ ~n~ention generally should be
coA~trued to cover all ~ch obvious for~ and
~odifi~tio~ ~d~ are ~ithiQ the true ~pirit ~rt.
