Note: Descriptions are shown in the official language in which they were submitted.
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Aqueous Compositions Thickened With
Acrylate-Based Polymeric Rheology Modifiers
The present invention is related to acid- and/or surfactant-containing
aqueous compositions having pH of less or equal to about 11, more
particularly from about 0.4 to about 10.5, which have been thickened with an
acrylate-based polymeric rheology modifier.
Rheology modifiers are used generally to adjust or modify the
rheological properties of aqueous compositions. Such properties include,
without limitation, viscosity, flow rate, stability to viscosity change over
time,
and the ability to suspend particles in such aqueous compositions. The
particular type of modifier used will depend on the particular aqueous
composition to be modified and on the particular end-use of that modified
aqueous composition. Examples of conventional rheology modifiers include
thickeners such as cellulosic derivatives, polyvinyl alcohol, sodium
polyacrylate, and other water-soluble macromolecules, and copolymeric
emulsions in which monomers with acid groups have been introduced onto
the main chain. Such thickeners are used widely in fiber treatment and
adhesives.
It has been reported that when thickeners such as cellulosic
derivatives and polyvinyl alcohol are mixed with aqueous emulsions, the
thickened emulsion tends to exhibit poor stability to viscosity change over
time. The cellulosics are said to result in a substantial decline in viscosity
over time. It also has been reported that large quantities of polyvinyl
alcohol
are required in order to thicken aqueous emulsions. When such thickened
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aqueous emulsions are used in, for example, adhesives and coatings, the
high levels of polyvinyl alcohol result in a loss of adhesive and/or cohesive
properties as well as a loss in water resistance in the films formed
therefrom.
Another class of rheology modifiers known to thicken aqueous
emulsions is one typically referred to as associative modifiers. Such
associative modifiers are reported in U.S. Patent Nos. 4,743,698, 4,600,761,
RE 33,156, 4,792,343, 4,384,096,3,657,175, 5,102,936 and 5,294,692. As
noted, these thickeners become effective upon the addition of base, thereby
raising the pH of the thickened composition to alkaline, but the thickeners
are
not designed to thicken aqueous compositions having a pH less than 7.
Other rheology modifiers which are "activated" by the addition of acid
to aqueous compositions which contain the modifiers also have been
reported. As reported, emulsions are prepared via free-radical emulsion
polymerization utilizing colloidal stabilizers. The emulsions are mixed with
the
composition to be thickened and then acid is added to the mix, thereby
lowering the pH of the system to 6.5 to 0.5. These thickeners are reported to
be effective at thickening certain acidic aqueous compositions, but are not
effective at thickening aqueous compositions having basic pH.
It would be desirable to develop a rheology modifier which is stable to
change in viscosity and phase separation over time, which does not
detrimentally affect film properties such as adhesive/cohesive properties and
water resistance, and which advantageously may be used to thicken both
acidic and basic aqueous compositions.
The present invention relates to thickened aqueous compositions
which have a pH of less than or equal to about 11, preferably from about 0.4
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to about 10.5, which compositions comprise a thickening amount of an
acrylate-based polymeric rheology modifier in the form of a stable, aqueous
emulsion; and an active ingredient selected from the group consisting of an
acid and a surfactant, said active ingredient being present in amounts
effective to provide to said thickened composition the performance
characteristics required for the particular end-use thereof. The stable
emulsion of the acrylate-based polymeric rheology modifier is prepared by
single-stage emulsion polymerization of from about 5 to about 80 weight
percent of an acrylate monomer (a) selected from the group consisting of a
C2-C6 alkyl ester of acrylic acid and a C1-C6 alkyl ester of methacrylic acid,
from about 5 to about 80 weight percent of a monomer (b) selected from the
group consisting of a vinyl-substituted heterocyclic compound containing at
least one of a nitrogen or sulfur atom, (meth)acrylamide, a mono- or di- (C,-
C,)alkylamino (C,-C,)alkyl (meth)acrylate, a mono or di-(C,-CQ)alkylamino (C,-
C4)alkyl (meth)acrylamide, 0 to about 2 weight percent of a cross-linking
monomer (c); and 0 to about 30 weight percent of an associative monomer
(d), all percentages based on the total weight of monomer. The emulsion
polymerization is conducted in the presence of water, a first surfactant in
amounts effective to emulsify the polymer in the water, a free-radical
initiator,
and from about 0.5 to about 20 weight percent of an alcohol selected from the
group consisting of a Ca C12 linear or branched monohydric alcohol and non-
polymeric polyhydric aicohols, such as ethylene glycol, propylene glycol and
glycerol, based on the total weight of the stable emulsion. The emulsion
, polymerization is conducted essentially in the absence of a polymeric
colloidal
stabilizer.
s_
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Thus, in more specific terms, the present invention provides an
aqueous composition having a pH of less than or equal to about 11,
comprising: a thickening amount of a stable emulsion of a poiymer, said
emulsion prepaned by sing"ape emuision poiymerization of monomers
selected from the group consisting of from about 5 to about 80 weight perr.ent
of an acrylate monomer (a) selected from the group consisting of a Cr-Ce
a)kyi ester of acrylic acid and a C1-Cs alkyl ester of methacrylic acid, from
about 5 to about 80 weight percent of a manomer (b) seieci:ed from the group
consisting of a vinyi-substih,ted heterocyciic compound containing at least
one of a nitroyen or sulfur atom, (meth)acryiamide, a mono- or di-(C,-
C4)alkylamino (C7-C4)alkyi (meth)acryiate, a mono- or di-(C.,-C4)aikylamino
(Cl-Ca)aikyi (meth)acryiamide, 0 to about 2 weight percent of a cross-linking
monomer (c), and 0 to about 30 weight percent of an associative monomer
(d), all peirsntages based on the total weight of monomer, wherein said
emulsion polymerization is conducted in the presence of water, a first
surfactant in amounts effective to emulsify the polymer in the water, a free-
radicai initiator and from about 0.5 to about 20 weight percent of an alcohol
selected from the group consisting of a C2-C2 2 linear or bnaricffied
monohydric
alcohol and a non-polymeric polyhydric alcohol, based on the total weight of
said emulsion, wherein said single-stage emulsion poiymerization is
conducted essentially in the absence of a poiymer~c colloidal stabitizer, and
a
minimum effective smourrt of an active ingredient setected from the group
consisting of an acid and a second surfactent.
3a
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Preferably, the thickening amount of the potymer emulsion comprises from 15
to 40 w8ight pert:ent of said polymer, based on the total weight of seid
emulsion.
3b
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in another embodiment, the emulsion comprises the composition of Claim '1 or 2
wherein
said emulsion comprises from 0.1 to 5 weight percent of sald first surfactant,
based on
the total weight of monomer, said first surfactant setected from the group
tonsisting of
anionic, cationic, nonionic, amphoteric and zwdterionic surfactants.
In yet another aspect of the invention, the emulsion comprises the composition
of Claim 5
wherein said emulsion comprises from 0.1 to 1 weight percent of said cross-
linking
monomer, based on the total weight of monomer.
in another embodiment, there is disdcsed a composition for use as a rheology
modifier in
aqueous systems having pH of less than or equal to 11, said composition
comprising- a
stable emuision of a polymer, said emulsion prepared by single-stage emulsion
polymerization of monomers seiected from the group consisting of from 5 to 80
weight
percent of an acrylate monomer (a) selected from the group consisting of a C2-
C6 alkyl
esters of acrylic acid and a C1-CB alkyl ester of inethacryiic acid, from 5 to
80 weight
percent of a monomer (b) selected from the group consisting of a vinyl-
substituted
heterocyGic compound containmg at least one nitrogen or sulfur atom,
(meih)acryiamide,
a mono- or di- (CI-C4)aikylamino (C,-C4)alkyl (meth)acylate, a mono or di-(Cl-
C4)elkyIamino (Cti-C4)eikyi (meth)acrylamide, 0 to 2 weight percent of a
aross4inking
monomer (c); and 0 to 30 welght percent of an asaociative monomer (d), all
percentages
based on the total weight of monomer, wherein said emuision polymerization is
condueted in the presence of water, a surfactant In an amount effective to
emulsify the
polymer In the water, afivwadical initiator, and from 0.5 to 20 weight percent
of an
alcohoi selected from the group consisting of a C2-C12 linear or branched
monohydric
alcohol and a non-polymeric polyhydric alcohol, based on the total weight of
said
emulsion, wherein said emulsion polymerixation Is conducted substantially in
the
absence of a potymeric colloidal stabilizer.
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Exemplary thickened aqueous compositions of the present Invention include,
without
limitation, deansers such as toiiet bowl cieaners, hard surface cieaners and
liquid hand
dishwaahing detergents, drilling fluid additives, saturants for corrugated
paper
manufaoture, adhesives, paints, inks, dyes and anti-stat coatings for paper.
The
emuisions are stable, meaning that no appreciable phase separation or change
in
viscosity is noted over time, for example one to five days at standard
temperature and
pressure, such that the emulsions may not be used to thicken aqueous
composittons
having pH of less than or equal to about 11.
The acrylate monomers (a) are selected from the group consisting of esters
prepared
from acrylic acid and C2 -C8 aicohois, such as ethyl or pnupyI alcohol, and
esters
prepared from methacayiic acid and Cl -C8 alcohols. (Meth)aaryiic sdd Is used
herein to
denote both ac;rylic add and methacrylic acid. Preferred acrylate monomers
comprise C2
-Ce aitryl esters of acrylic acid. Even more preferred, the acrylate monomer
is ethyl
acrytate_ From about 5 to about 80 weight percent of the acrylate monomer are
used in
preparing the composition of the present Invention, based on total weight of
monomer.
Preferably from about 15 to about 70 weight percent of the acrylate monomer
are used,
based on total weight of monomer. More preferably, from about 40 to about 70
weight
percent oF the acryiate monomer are used.
Methyl acrylate should not be used in preparin9 the emuisions and is not
induded within
the metes and bounds of this invention, as it haa been found to result In
emulsions which
are unstable with respect to viscosity change over time- It was unexpected
that polymers
prepared in the absence of a polymeric colloidal stabilizer with ethyl
aCrylate provided
stabillty to viscosity change over time when compared to polymers prepared in
the
absence
4a
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of a polymeric colloidal stabilizer with ethyl acrylate provided stability to
viscosity change over time when compared to polymers prepared in the
absence of a polymeric colloidal stabilizer with methyl acrylate, as emulsions
prepared with methyl acrylate were found to be unstable to viscosity change.
In addition to the acrylate ester (a), polymerized therewith is a
monomer (b) selected from the group consisting of a vinyl-substituted
heterocyclic compound containing at least one of a nitrogen or sulphur atom,
(meth)acrylamide, a mono- or di- (C,-C4)alkylamino (C,-C4)alkyl (meth)-
acrylate, a mono or di-(C,-C4)alkylamino (C,-C4)alkyl (meth)acrylamide.
Exemplary monomers include N,N-dimethylamino ethyl methacrylate, N,N-
diethylamino ethyl acrylate, N,N-diethylarnino ethyl methacrylate, N-t-
butylamino ethyl acrylate, N-t-butylamino ethyl methacrylate, N,N-dimethyl-
amino propyl acrylamide, N,N-dimethylamino propyl methacrylamide, N,N-
diethylamino propyl acrylamide, N,N-diethylamino propyl methacrylamide.
From about 5 to about 80 weight percent of the monomer are used in
preparing the modifiers of the present inverition, based on total weight of
monomer. Preferably, from about 10 to about 70 weight percent of the
monomer are used, based on total weight of nionomer. More preferably, from
about 20 to about 60 weight percent of the monomer are used.
In addition to the required monomers,-monomers which provide cross-
linking in the polymer may also be utilized in relatively low amounts, up to
about 3 weight percent, based on the total weight of monomer. When used,
the cross-linking monomers preferably are used at levels of from about 0 to
about 2 weight percent, based on total weiqht of monomer. Cross-linking
monomers include multi-vinyl-substituted arorriatic monomers, alicyclic
5
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monomers selected from the group Consisting of cycloparrafins and
cyclooletins, di-
furtctional esters of phthallc acid, di-functional esters of inethacryiic
alcid, multi-functional
esters of acrylic acid, dienes, trienes, tetraenes, and N-methylene-Bis-
acrylamide.
Exemplary cross-Iinking monomers include divinyibenzene, trivinylbenzene,
1,2,4-
tricinylcyciohexane, 1,5-hexadiene, 1,5,9-decatriene, 1,9-decadiene, and 1,5-
heptadiQne,
di-allyl phthelate, ethylene glycol dimethaaylate, polyethylene glycol
dimethacrylate,
pente- and tetra-acryiates, and N-methylene-Bis-acrylarride. The polyethylene
glycol
dimethacryiates are partiouiariy preferred for thickening In acid aqueous
compositions, as
they tend to minimime turbidity.
In certain preferred embodiments, an associative monomer may be used to
prepare the
rheology modifiens, in amounts up to about 30 weight percent, besed on total
weight of
monomer. When used, the associative monomers preferabiy are used at lavels
ranging
from about 0.1 to about 10 weight percent, based on total weight of monomer.
Such
monomers indude those disclosed In U.S_ Pat. Nos. 3,667,175, 4,384,096,
4,616,074,
4,743,698, 4,792,343, 5,011.978, 5,102,936, 5.294,692, and U.S. Pat. No. Re.
33,156.
Preferred associetive monomers include the urethane reaction products of a
monoethylanically unsaturated Isocyanate and non-ionic surFactants comprising
Cl -C4
aikoxy-terminated, block copotymers of 1,2-butylene oxide and 1,2-ethyiene
oxide, as
disclosed in U.S. Pat. No. 5,294,892 (Barron et al.), an ethyianiC111ty
unsaturated
copolymerizable surfactant monomer obtalned by condensing a nonionic
surfactant with
methylenesucciniC acid (also known as Itaconic acid) as disclosed In U.S.
6
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Pat. No. 4,616,074 (Ruffner), a surfactant monomer selected from the urea
reaction
product of a monoethylenicaify unsaturated monoisocyanate with a nonionic
surfactant
having amine functionaiity as disclosed in U.S. Pat. No. 5,011,978 (Barron et
al.), and a
nonionic urethane monomer which is the urethane reaction product of a
monohydric
nonionic surfactant with a monoethylenicaily unsaturated monoisocyanate,
preferably one
lacking ester groups such as aipha, alpha-dimethyl-m-iso-propenyl benzyl
isocyanatQ as
disclosed In U.S. Pat. No. Re. 33,156 (Shay et al.). Particularly preferred
are the
ethyienically unsaturated copolymerizable surtactant monomers obtained by
condcnsing
a nonionic surfactant with methylenesuccinic acid. Methods for preparing such
monomers
are disdosed in detail in the various patents referenced herein above.
The rheology modifier is prepered first by forming an emuision uttliztng
single-stage
emulsion polymerization techniques. Monomer, water, free-radicai initiator, a
first
surfactant in amounts effective to disperse the polymer in the water upon
polymerization
of the monomers, and from about 0.5 to about 20 weight percent of an alcohol
selected
from the group consisting of a C2 -C12 linear or branched monohydric 7tlcohoi
and a non-
polymeric po{yhydric aioohoi, such as ethylene glycol, propylene glycol and
glycerol,
based on total weight of the emuision, are combined in a polymerization
reactor and
maintained at a desired temperature and for a period of time which are
effective to
polymerize the monomers, theneby forming a polymeric emulsion comprisins the
copolymer of monomers (a) and (b), water, surfactant and alcohol.
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The contents of the polymerization vessel preferably are maintained
at a temperature and for a period of time effective to cause polymerization of
the monomers. Preferably the polymerization reaction is initiated at about 30
degrees Centrigrade, with the contents of the polymerization vessel attaining
a temperature of about 60 degrees Centigrade. The reaction time will be from
about 1 to about 6 hours. One skilled in the art of emulsion polymerization
will
be able to ascertain readily exactly what conditions of temperature and time
are required, as both are well within the knowledge of one skilled in the art.
Preferably, from about 1 to about 10 weight percent of the alcohol are
used and, more preferably, from about 1 to about 5 weight percent of the
alcohol are used, based on the total weight of the emulsion. If no alcohol, or
an insufficient amounts of the alcohol, is used in preparing the emulsion, the
resultant emulsion will not be stable to change in viscosity over time. It is
desirable to minimize the level of alcohol used. The maximum amount of
alcohol used may be limited practically by factors such as cost, flammability
and volatile organic compound environmental concerns. Other than those
factors, amounts of alcohol in excess of 20 weight percent conceivably may
used.
It is essential that polymeric colloidal stabilizers such as polyvinyl
alcohol not be used during preparation of the emulsion via emulsion
polymerization in any amount which materially alters the properties of the
emulsion, particularly the emulsion stability. Preferably, no polymeric
colloidal
stabilizer is used during emulsion preparation. It was discovered surprisingly
that use of such polymeric colloidal stabilizers results in emulsions which
are
2 5 not stable to changes in viscosity or phase separation over time.
Accordingly,
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the emulsions and rheology modifiers comprising the emulsions essentially
are free and more preferably are free of polymeric colloidal stabilizers.
Thickened aqueous compositions according to the present invention,
in addition to containing a thickening amount of the acrylate-based, stable
aqueous emulsion, that is, an amount effective to thicken the aqueous
composition compared to a comparable composition which does not contain
the acrylate-based emulsion, will also comprise a minimum effective amount
of an active ingredient selected from the group consisting of an acid and a
second surfactant. Preferably, the thickened composition will comprise
enough of the emulsion such that the thickened composition comprises
greater than about 0.5 dry weight percent of the emulsion polymer on a dry
weight basis, based on total weight of the thickened aqueous composition,
and more preferably from about 0.5 to about 20 dry weight percent of the
polymer, based on total weight of the thickened composition. Most preferably,
the thickened composition will comprise from about 1 to about 10 dry weight
percent of the emulsion polymer, based on total weight of the thickened
composition.
By minimum effective amount, it is meant that the active ingredient
will be present in the thickened aqueous composition in a minimum amount
effective to provide the thickened aqueous composition with the particular
performance characteristics required for the particular end-use of the
thickened composition. For example, where the thickened composition is a
cleanser, the composition must provide cleaning performance, as described
below. In some cases, the surfactant may be used to enhance the thickening
efficiency of the acrylate-based emulsion, for instance in an ink paste base
or
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in an acid-containing cleanser: Accordingly, the thickened composition may
comprise from about 0.1 to about 95 active weight percent of surfactant
and/or from about 0.1 to about 50 active weight percent acid, based on total
weight of the thickened composition, with the balance being polymer and
water, as well as possibly other optional conventional ingredients utilized in
thickened compositions described herein.
The actual active ingredient and the actual minimum effective amount
will be determined by the actual prod uct/appi ication in which the thickened
composition is to be used. For example, where the end-use is a cleaning
composition such as a toilet bowl cleaner, a hard surface cleaner or a liquid
hand dishwashing detergent, the active ingredient is selected from the group
consisting of an acid and a second surfactant, present at a minimum amount
effective to achieve minimum cleansing performance. By minimum cleansing
performance, it is meant that the active ingredient is present in minimum
i5 amounts effective to clean or remove deposits from the surface of
substrates
to which the thickened aqueous compositions have been applied. For
example, where the composition is applied to toilet bowls, an acid will be
present in minimum amounts effective to remove salts and stains caused by
continuous and/or repeated exposure to water, for example iron salts such as
rust and the like. In this case, the thickened composition may comprise from
about 0.1 to about 50 active weight percent of the acid, more preferably from
about 2 to about 50 active weight percent of acid, based on total weight of
the
thickened composition.
Where the compositions are applied in the form of a liquid hand
dishwashing detergent to, for instance, dishes and plates, a second surfactant
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C
will be present in minimum amounts effective to remove deposits such as oils
and fatty substances emanating from food products, dried food products
themselves, dirt, and so forth. Preferably, such cleaning composition will
comprise from about 2 to about 95 active weight percent of the second
surfactant, more preferably from about 5 to about 95 active weight percent of
the second surfactant, based on total weight of the thickened aqueous
composition.
Exemplary acids used in compositions of the present invention
include, without limitation, citric, sulfuric, hydrochloric, phosphoric,
acetic,
hydroxyacetic, and sulfamic acids. Synergistic thickening of compositions
comprising an amount of an acid required for a desired performance have
been surprisingly noted where a second surfactant selected from the group
consisting of a nonionic and anionic surFactant is added to the composition.
In those cases, the addition of the second surfactant has been found to
improve thickening efficiency by as much as eighty fold, depending on the
amount of surfactant added to the aqueous composition which comprises an
acid. In these cases, the second surfactant need not be present at a level
greater than that necessary to impart synergistic thickenening of the
composition, as the acid performs the primary application function and the
second surfactant serves to improve the thickening efficiency of the acrylate-
based emulsion.
Thickened aqueous compositions according to the invention also
include those compositions which comprise a second surfactant in minimum
cleansing amounts. Such thickened compositions include, for example, liquid
hand dishwashing detergents. Exemplary second surfactants which may be
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used in the thickened aqueous compositions include, without limitation,
sodium lauryl sulfate, (di)alkylsulfosuccinates, alkyl sulfonates, alkyl
ti
phosphates, alkyl ethoxylates, and alkylaryl ethoxylates. It should be noted
that the second surfactant is in addition to the first surfactant, which will
be
present in the aqueous composition due to its presence in the acrylate-based
emulsion. Accordingly, the second surfactant may be formulated or blended
into the aqueous composition after the emulsion has been prepared, and
should not be confused with the first surfactant_ While the second surfactant
may be the same as the first surfactant, it is preferred that the second
surfactant be selected from the group consisting of anionic and nonionic
surfactants, and thus may be different than the first surfactant used to
prepare
the emulsion.
In addition to the above essential elements of the invention, the
thickened aqueous compositions may further comprise conventional
ingredients known to be used therein.
The following examples are set forth merely to exemplify the invention
and are not intended to limit the metes and bounds of the invention, which is
set forth by the claims appended hereto.
Example 1: Acid Thickening
Two emulsions were prepared according to procedures set forth
herein above and designated Emulsions 1A and 1B respectively. Each
emulsion was prepared at twenty (20) weight percent polymer solids, based
on total weight of the emulsion, utilizing acrylate-ester and alkylamino
(meth)acrylate monomers. Each emulsion was incorporated into an acid-
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containing solution at a level such that the polymer solids, based on total
weight of the thickened composition, are as set forth in Table 1.
TABLE 1
Emulsion sample 121 Brookfield Viscosity (cPs)
pH initial 1 day 5 day 35 day
Emulsion IA (20% 8.2 50 60 66 92
polymer solids)
3% 1A in 5% citric acid 2.2 3200 6000 6000 5300
3% 1A in 5% 2.2 2200 4500 4000 4400
hydroxyacetic / 5%
sulfamic acid blend
4% 1A in 9% 0.4 740 2060 1900 ------
hydrochloric acid
Emulsion 1B (20% 8.2 108 280 310 1550
polymer solids)
3% 1 B in 5% citric acid 2.2 6000 8000 8700 8550
3% 1 B in 5% 2.3 4150 7000 6800 6800
hydroxyacetic / 5%
sulfamic acid blend
[1j Brookfield viscometer model RVDVII+ ; All measurements obtained
with spindle #2 @ 20 rpm, 21 C.
[2] All values are listed in dry weight % on total composition weight; e.g.
3 % 1A polymer solids and 5 % ciTric acid solids, based on total weight of
thickened composition.
Example 2: Surfactant Thickening _
Stable emulsion 1 A was added at the noted polymer solids to a blend
of anionic and nonionic surfactants (2(a)) typical of commercially available
liquid hand dishwashing detergents. The pH and Brookfield viscosity of the
surfactant blend were recorded both prior to and after addition of the stable
emulsion. The surfactant composition pH was then adjusted with addition of
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50% sodium hydroxide solution to a pH 10 and the resulting Brookfield
viscosity was recorded Again, the stable emulsion product unexpectedly
provided a significant increase in the viscosity of the surfactant blend at pH
8.4 as well as pH 10.
Additional samples of anionic and non-ionic surfactants were selected
for investigation of the ability of the stable emulsion thickener
representative
of this invention to thicken aqueous compositions comprising a second
surfactant as the active ingredient. It is significant to note that the
compositions of this example contain no acidic components, and no acid
substances are added as neutralizing agents, compatibilizers, stablizers, or
the like. The data contained in TABLE 2 includes as-is viscosity and pH
measurements for an anionic surfactant (sodium lauryl sulfate, 2(d)) and a
non-ionic surfactant (nonylphenol 4 mole ethoxylate (2(f)). The table also
provides the resulting viscosity and pH of the referenced surfactant samples
after addition of a noted level of the stable emulsion thickener IA of this
invention, demonstrating the ability of the stable emulsion thickener to
provide
an unexpected and substantial increase in the surfactant viscosity at an
alkaline pH .
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TABLE 2
Sample # Description pH Brookfield Viscosity 121
(cPs)
2(a) Commercial Anionic / Nonionic 8.2 540
surfactant blend
2(b) Sample 2(a) with 1.2 % 8.4 1270
Emulsion 1A added M
2(c) Sample 2(b) with added 10.0 930
sodium hydroxide
2(d) Sodium lauryl sulfate (30 % 8.6 94
active in water)
2(e) Sample 2(d) with 1.25 % 1A 9.3 738
emulsion added I'l
2(f) Nonylphenol ethoxylate 9.3 386
2(g) Sample 2(f) with 2.2 % 1A 8.1 1060
emulsion added
[1] dry polymer weight % on total composition weight;
[2] spindle #2 @ 20 rpm, 21 C.
Example 3:Thickening Surfactant Containing Acidic Systems
Evaluation of the interaction of the stable emulsion product in an
acidic system containing surfactant provided the data in TABLE 3, below. A
solution containing 5 active weight % of citric acid was prepared. Addition of
the stable emulsion product at a level of 2 % dry polymer on total solution
weight yielded a significant increase in the citric acid solution Brookfield
viscosity. To the thickened acid solution was added, in 2 gram increments, an
ethoxylated alkylphenot surfactant (HLB 8.8). Viscosity response to the
incremental addition of the nonionic surfactant was recorded and
= demonstrates the ability of the stable emulsion product to thicken systems
containing both acid and surfactant. Increasing the HLB of the added
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surfactant over the surfactant referenced in TABLE 3 is expected to provide
an initial increase in the system viscosity that will more rapidly decrease
with
continued addition of the surfactant versus the referenced TABLE 3 viscosity
data. =
TABLE 3
Sample # Sample Description Brookfield
Viscosity
(cPs) I'I
3(a) 5 % Citric acid121 solution <10
3(b) 3(a) + 2%1A emuisionE21 216
3(c) 3(b) + 2 grams nonionic surfactant 4460
3(d) 3(b) + 4 grams nonionic surfactant 6200
3(e) 3(b) + 6 grams nonionic surfactant 8000
3(f) 3(b) + 8 grams nonionic surfactant 11200
3(g) 3(b) + 10 grams nonionic surfactant 16000
3(h) 3(b) + 12 grams nonionic surfactant 16000
3(i) 3(b) + 14 grams nonionic surfactant 9500
3(j) 3(b) + 16 grams nonionic surfactant 7200
3(k) 3(b) + 18 grams nonionic surfactant 6110
3(l) 3(b) + 20 grams nonionic surfactant 5000
[1] Brookfield Viscometer model RVDVII+; All measurements obtained
with spindle #2 @ 20 rpm, 21 C.
[2] Solids weight percent based on total weight of solution.
16
