Note: Descriptions are shown in the official language in which they were submitted.
2 ~ 3
CP-IR-482
LINEAR VISCO~LASTIC AQUEOUS LIQUID
DBT~RG~NT COMPOSITION, ~SP~CIALLY FOR
AUTOMATIC DISHWASHERS, OR IMPROVED HIGH
TEMPERATURE STABILITY
Field of Invention
The ~nvention relate~ to aqueous linear viscoelastie
(gel-like) liquid compo~ition~ which are especially useful as
automatic dishwasher detergent ¢ompo~ition~.
,~.,
Backqround of the Inven~ion
L~quid automatic dishwa~her detergent compo~itions,
both aqueous and nonaqueouo, have recently received muah
attention, and the aqueou~ products have achieved commercial
popularity.
The aceeptanee and popularity of the liquid
formulations as eompared to the more aonventional powder product~
stem~ from the convenienee and performanee of the liquid
product~. However, even the be~t of the eurrently ava~lable
liquid formulations still suffer from two ma~or problems, product
pha~e in~tability and bottle residue, and to some extent cup
leakage from the dispenser eup of the automatie dishwashing
~machine.
i
!
',.
J ~
2~3~23
Representative patent art in thi~ area include~ Rek,
U.S. Patent 4,556,504; Bush, et al., U.S. Patent 4,226,736;
Ulrich, U.S. Patent 4,431,559; Sabatelli, U.S. Patent 4,147,650;
Paucot, U.S. Patent 4,079,015; Leikhem, U.S. Patent 4,116,849;
Milora, U.S. Patent 4,521,332; Jones, U.S. Patent 4,597,889;
Heile, U.S. Patent 4,512,908; Laitem, U.S. Patent 4,753,748;
Sabatelli, U.S. Patent 3,579,4~5; Hynam, U.S. Patent 3,684,722.
Other patents relating to thickened aqueous detergent
compositions include U.S. Patent 3,985,~68 U.K. Patent
Applications G~ 2,116,199A and GB 240,450A; U.S. Patent
4,511,487; U.S. Patent 4,752,409 (Drapier, et al.); U.S. Patent
4,801,395 (Drapier, et al.); U.S. Patent 4,836,946 (Dixit); U.S.
Patent 4,889,653 (Ahmed, et al.). Commonly a~signed co-pending
patents include, for example, Serial No. 427,912 filed October
24, 1989; Serial No. 924,385, filed October 29, 1986; Serial No.
323,138, filed Marah 13, 1989; Serial No. 328,716, filed March
27, 1989; Serial No. 323,137, filed March 13, 1989; Serial No.
323,134, filed March 13, 1989.
The solubilizing effect of pota~sium ~alts on 30dium
tripolyphosphate in aqueous detergent compositions i~ described
in U.S. Patent 3,720,621 (Smeets~. Thi~ patent de~cribes
homogeneous liquid composition~ containing 14 to 35 percent
~odium tripolyphosphate, 0.1 to 50 percent of potassium and/or
ammonium salt of an inorganic or organic acid, water, and
optional ~urfactant~, ~olubilizing agent, organic eequestering
agent, per-compound, and other adjuvant~. Potassium
pyrophosphate (T~PP) is dieclosed ae the preferred potassium salt
for its ~equestering and solubilizing actlvity and al~o because
"it effectively stabilizes the tripolyphosphate agent hydroly~is
in aqueous ~olution into sodium pyropho~phate and ~odium
'- .-' . , ','''.. : : . . , ', '''', -, '
J ~ 2 ~ ~ .'3 ~3 i~
orthophosphate." Th~ patent al~o ~tate~ that, "[t]he content [of
TKPP] ~hould not ... be too great 80 as to undergo a double-
decomposition reaction with TPP to form ~odlum pyrophosphate,
which is well ~nown, has a very low solubility in water and,
therefore, tends to ~eparate out as a precipitate. The
applicants investigations have ~hown that the optimum proportion
of potas~ium pyrophosphate incorporated ~n the liquid detergent
compoqitions ... i~ between 5 and Z5 percent based on the TPP
present in the compositions."
U.S. Patent 4,836,948 discloses a vi~coela~tic gel
detergent composition characterized by its viscoeity under low
and high shear conditions, pH, and steady ~tate viscoelastic
deformation compliance. The composition requires the presence of
a polycarboxylate polymeric thickener, preferably a cross-linked
polyacrylic acid. The compos~tions of this patent also,
however, require a trivalent metal conta~ning material,
especially an aluminum containing material ~uch as alumina. ~he
compo~itions may further include a structuring chelant which may
be a salt of carbonate, pyrophosphate or mixture thereof, and
preferably the pota~sium salts.
The recently issued V.S. Patent 4,859,358 discloses the
incorporation of metal salts of long chain hydroxy fatty acids,
a6 anti-tarnishing agents, in thickened aqueous automatic
dishwashing detergent compositions. The thickeners for these
compositions may be a high molecular weight polycarboxylate
polymer, such as those sold under the Carbopol trade name, and
specific 600 and 900 ~eries resin~ are mentioned. It is also
disclosed that the compositions may include entrained gas, e.g.
air, bubbles to further ~nsure stability. Amounts of air in the
range o~ from about 1% to about 20%, preferably from about 5 to
.. ..
.. . . , : .: ,: .
. :; . ,
15~ by volume will lower the specific gravity of the overall
composition to within from about ~ more than to about 10~ le~
than, preferably from 1% more thnn to 5% les~ than, the specific
gravity of the aqueous phase. In Example III of this patent, the
~pecific gravity of the composition wa~ ~tated a~ 1.32 g/cm3.
The compositions are not described a~ being linear vi~coelastic
and as exemplified do not include any potassium salts.
While the compositions disclosed in our prior
application Serial No. 353,712 provided a satisfactory ~olution
lo to the problems of phase instability and bottle residu~, as well
as cup leaknge, it has now been found that under ~ome
storage/handling conditions and/or processing condition~,
additional imp~ovements would be desirable. Specifically, if the
viscoelastic composition is subjected to repeated heating and
cooling cycles, growth of crystals and product thinning and/or
precipitate formation has been ob~erved. Chemical analysi~ of
the precipitated crystal~ has shown that these cryetals are
comprised predominantly of sodium pyrophosphate. In addition, it
appears that the crystals tend to become entangled with the
polymeric thickener which tendency i~ presumed to account for the
thinning out or aqueous phase separation which has been observed
in conjunction with crystal formation and precipitation.
Another problem which has been encountered in the
preparation of the linear viscoelastic gel formulations of our
prior application involved the manner by which the preferred
Carbopol thickener is added to water. Specifically, if in
forming the slurry of the Carbopol type thickener, the water
temperature is maintained at ambient temperature conditions, e.g.
60-80F, the polymer tend~ to be only incompletely hydrated,
i.e. results in formation of fish eye~.
., , ., ' . ' ' . . . , . ! '
,~ 2l~
AB a re~ult of these problems, the finished product not
only may be perceived as unaesthetic but, more importantly, the
roduct ViBCo8ity iB often lowered which in turn may lead to cup
leakage and corresponding degradation in cleaning performance.
It ha~ also been discovered that there is an important
relationship between the pH of the composition at each ~tage
uring processing and product stability, including both phase
separation and loss of viscosity.
The presQnt invention provides iDgredient and
processing modification~ to our previously developed compositions
which help to alleviate and overcome the above problem~.
Brief De~criPt~on of the ~rawinas
Figures 1-6 are rheograms, plotting elasti~ modulus G'
and viscous modulus G" as a functlon of applied strain, for the
compositions of Example 1, Formulatlons A, ~, C, D, E and F,
respectively.
Summar~ of tha Invention
According to the present invention there is provided an
improved aqueou~ liquid automatic dishwasher detergent
composition. The composition is characterized not only by its
linear viscoelastic behavior, substantially indefinite ~tability
against phase separation or settling of dissolved or suspended
particle~ under high and low temperature conditions, low levels
of bott}e re~idue, relatlvely high bulk den~lty, and sub~tantial
absence of loosely bound water,but also by itB overall product
con3istency from batch to batch and run to run and over a wide
range of storage and aging conditions, including superior
' . .' . ', '' , ' . " " '' .,:' . ' '
~ 3 ~ 3
aesthetics, freedom from fish-eye~, absenoe of crystal formation
and growth, and resietance to cup leakage.
The present invention was accomplished based, in part,
on the diecovery that by repla¢ing part or ~11 of the
tetrapotassium pyrophosphate (T~PP) with potas~ium
tripolyphosphate (K~PP), cry~tal growth can be inhibited and
product consi~tency can be improved and the linear viscoelastic
propertie~ can be extended beyond that previou31y achieved.
Further improvements are obtained by utilizing more highly
cross-linked and branched, temperature stable and bleach and ~alt
compatible polymeric thickening agent~. Furthermore, by
controlling the condition~ of mixing the ingredients of the
compoeitions, 'and particularly the pH and temperature of the
aqueou~ phase used to form the aqueous ~olution of the polymeric
thickener, formation of fish-eyes and elimination of viscosity
reductions with time can be achieved.
Accordingly, in one aspect the present invention
provides an improved linear viscoelastic aqueous liquid automatic
¦di~hwasher detergent composition compri~ing water, up to about 2%
by weight of long chain fatty acid or salt thereof, from about
0.1 to 5% by weight of low-foam~ng chlorine bleaoh stable, water
dispereible automatic diehwaeher non-~oap organ~a detergent, from
about 10 to 35% by weight of alkali metal detergent builder
salt, at lea~t 50~ by weight of which i8 potas~ium
tripolyphosphate and at least about 5~ by weight of which is
eodium tripolypho~phate, from about 3 to 20~ by weight of a
chlorine bleach compound, and a crose-linked polyaarboxylate
thickening agent having a molecular weight of at least about
500,000, wherein the aqueous pha~e include~ both sodium and
potas~ium ions at a K/Na weight ratio of from about 1/1 to about
, : .. . -: ; . .
' . ' .,'' : . .'.,-.
, . , . - .: .. ..
~ ~3~2
45/1. The aompositions preferably have a bulk density of from
about 1.28 g/cm3 to about 1.42 g/cm3.
In a preferred embodiment, the linear vi~coela~tic
aqueous li~uid automatic dishwasher detergent comprise~,
approximately, by weight,
(a)(i) 8 to 25% pota~ium tripolyphosphate detergent
builder,
. (ii~ 2 to 10% sodium tripolyphosphate detergent
builder, at an (i)/(ii) weight ratio of from about 1.4/1 to :
10/1;
(b) 5 to 15~ alkali metal silicate;
(c) 1 to 6% alkali metal hydroxide;
(d) b.1 to 3% chlorine bleach stable, water-dispersible
organic detergent active material;
(e) 0.05 to 1.5% chlorine bleach stable foam
depressant;
(f) chlorine bleach compound in an amount to provide
about 0.2 to 4% of available chlorine;
~ g) 0.4 to 1.5~ hydrophilic crose-linked water
insoluble polycarboxylate thickening agent having a molecular
weight of from 800,000 to 4,000,000 to provide said linear
viscoela~tic property;
(h) 0.08 to 0.4% of long chain fatty acid or a metal
salt of a long chain fatty acid as a physical stabilizer to
increa~e the physical stability of the composition;
~ i) 0 to 10% of a non-cross-linked polyacrylic aaid
having a molecular weight in the range of from about 800 to
200,000; and .
(j) water;
! '
~ ~3~ .3
and wherein in the entire compo~itlon, the ratio, by weight, of
pota~sium and sodium iB from about 1.05/1 to 3/1.
In another aspect of the invention, ~ method for
preparing the aqueou~ linear vi~coela~tic composition iB
provided. According to this aspect, the method compri~e~ the
step~ of
I. (a) fully hydrating the cro~s-linked polycarboxylate
thickener by slowly adding the thicksner to heated water while
moderately agitating the mixture,
(b) ~lowly adding a neutralizing amount of cau~tic
~oda to the mixture from (a) while continuing agitation to obtain
a disper~ion of the neutralized thickener;
II. ~c) forming an aqueou~ mixture of ~urface active
agent~;
~d) heating the mixture in (¢) to a temperature
higher than that of the heated water in ~a) and mixing until a
homogeneou~ ~mooth premix i8 obtained;
III. (e) uniformly mixing alkali metal builder ~alt~
with the dispersion (b),
(f) uniformly mixing the heated premix (d) with
the mixture (e),
(g) cooling the mixture (f) to a temperature above
the temperature of the heated water in ~tep (a), and
(h) adding bleach to the mixture (g).
In a preferred embodiment of the lnvention proces~, the
pH of the aqueous slurry of the cross-linked polycarboxylate
thickener after the neutralization in ~tep (b) and in each
6ucceeding ~tep is maintained at a value of at lea~t 11.
. .. . . . . . .
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- .. - - .' . ' . . .. '
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Detailed De6cription and Preferred Embodiments
The compo~ition~ of this ~nvention are thickened
aqueou~ liquids containing various cleansing active ingredients,
detergent builder ~alt~ and other detergent adjuvants,
gtructuring and thickening agents and etabilizing components,
although some ingredisnt~ may serve more than one of these.
functions.
The advantageou~ characteristics of the compositions of
this invention, include physical ~tability, as manifested by
little or no phase separation, solid settling or vi~cosity
changes over time or resulting from exposure to low or high
temperatures, low bottle residue, low cup leakage, high cleaning
performance, e'.g. low spotting and filming, dirt residue removal,
and consistency in product characteristic~.and performance, and
superior aesthetics. These characteri~tics are believed to be
attributed to several interrelated factore such a~ low solid~,
i.e. undissolved particulate content, product den~ity and linear
viscoelastic rheology. ~hese factors are, ln turn, dependent on
several critical c.ompositional components and processing
conditions of the formulations, namely, (1) the inclusion of a
thickening effective amount of a temperature, bleach and salt
stable cros~-linked polymeric thickening agent having high water
absorption capacity, exemplified by cross-linked polyacrylic
: acid, (2) inclusion of a physical stabilizing amount of a long
chain fatty acid or salt thereof, and (3) potassium ion to sodium
ion weight ratio K/Na in the range of from about 1:1 to 45:1,
especially from 1:1 to 3:1, and preferably also (4)-(6): (4) a
product bulk density of at least about 1.28 g/cc, especially at
least 1.32 g/cc, (5) hydrating the cross-linked polymeric
thickener with heated water, and (6) maintainlng the pH of the
. , .- - , ,' . . .
. . , :. -
.. . . . . . :
.. . . - ... . . ~ .. : . - , -
~ 3;3 ~ r~
eutralized polymeric thickener at a p~ of at least 11,
referably at lea~t 11.5.
In particular, the linear viscoelastic aqueous liquid
utomatic dishwasher detergent compositions of thi~ invention
ill, at least in the preferred embodiments, satiafy each of the
ollowing stability criteria over the aging temperature-time
chedule shown by the following Table As
- TABLE A
ging Temperature Duration
(F) ~Weeksl
Minimum Prsferred
140 ~ 1 ~ 2
120 ~ 6 ~ 8
100 ~ 13 ~ 16
Ambient ' ~ 24 >> 24
More ~pecifically, the compoeitions are aonsidered stable if each
f the following stability criteria is satiefied for at least the
inimum number of weeks for each aging tsmperature shown in Table
s
. no visible phase separation (i~e. no solid/liquid
separation)
. no ~ignificant change (e.g. less than 10%) in
iscosities, yield stress or other dynamic-mechanical properties
. no crystal growth under repeated heating-cooling
ycles over a temperature range of at least 7F to 140F
. no deaolorization or signif~cant color change.
In addition to the above stabillty crlteria, the oompositLons of
this inventlon are further characterized by their low bottle
residue. Specifically, for the preferred cross-linked
polyacrylic acid thickened compositions of this invention, bottle
residue~, under the usual use conditions, will be no more than
:. . . . .
, -
.. . . . .
~ 3
bout 6 to 8~, preferably no more than about 4 to 5%, of the
riginal bottle contente, on a weight basis.
~he polymeric thickening agents contribute to the
inear viscoelastic rheology of the invention compo~itions. A~
sed herein, ~linear viscoela~tic~ or "linear viflcoelasticity"
ean6 that the elastic (storage) moduli (G') and the viscous
1OB8) moduli (G") are both substantially independent of strain,
t least in an applied strain range of from 0-50~, and preferably
ver an applied strain ~ange of from 0 to 80%. More
pecifically, a compoBition iB considered to be linear
iscoelastic for purposes of this invention, if over the strain
ange of 0-50~ the elastic moduli G' has a minimum value of 100
ynes/sq.cm., prefsrably at least 250 dynes/sq.cm., and varies
es~ than about 500 dyne~/~g.cm., preferably les~ than 300
ynes/~.cm., especially prefera~ly less than 100 dynes/sq.cm.
referably, the minimum value of G' and maximum variation of G'
pplies over the strain range of 0 to 80%. Typically, the
ariation in 1088 moduli G~ will be le~e th~n that of G'. As a
urther characteristic of the preferred linear viscoelastic
ompo~itions the ratio of G"/G' (tan ~) is less than 1,
referably less than 0.8, but mors than 0.05, preferably more
han 0.2, at lea~t over the strain range of 0 to 50%, and
referably over the strain range of 0 to 80%. It should be noted
n this regard that % ~train is shear strain xlO0.
By way of further explanat~on, the elastic (storage)
modulus G' iB a measure of the energy stored and retrieved when a
train iB applied to the composition while viscous (1088) modulus
" is a measure of the amount of energy dissipated as heat when
train is applied. Therefore, a value of tAn ~,
0.05 ~ tan ~
203.~23
preferably
0.2 ~ tan~S ~.8
means that the composition~ wLll retain ~ufficient energy when a
stress or strain i8 applied, at lea~t over the extent expected to
be encountered for products of this type, for example, when
poured from or 6haken ln the bottle, or stored in the dishwasher
detergent dispenser cup of an automatic dishwashing machine, to
return to itB previous condition when the stress or strain i8 .
removed. The compositions with tan ~ values in these ranges,
therefore, will also have a high cohesive property, namely, when
a shear or strain is applied to a portion of the composition to
cause it to flow, the ~urrounding portion~ will follow. AB a
re~ult of this'cohesiveness of the linear vl~coelastic
characteristic, the ¢ompositions will rea~ily flow uniformly and
homogeneou~ly from a bottle when the bottle i~ tilted, thereby
contributing to the physical (pha~e) stability of the formulation
and the low bottle residue (low product 108~ in the bottle) which
characterizes the invention composition~. The linear
vi~coelastic property also contributes to ~mproved phy~ical
st~bility again~t phase separation of any undis~olved suspended
particles by providing a resi~tance to movement of the particle~
due to the 6train exerted by a particle on the surrounding fluid
medium. ~inear vi~coela~ticity also contributes to the
elimination of dripping of the contents when the product iB
poured from a bottle and hence reduction of formation of drops
around the container mouth at the conclusion of pourlng the
product from a container.
A1BO contributing to the physical ~tability and low
bottle residue of the invention compo~itions iB the high
potassium to sodium ion ratio~ in the range of 1~1 to 45:1,
. . . ' . . . ..
': ' ' ' .~ .
preferably 1:1 to 4sl, especially preferably from 1.05:1 to 3:1,
for example 1.1:1, 1.2:1, l.S:l, 2:1, or 2.5:1. At these ratios
the- solubillty of the solid salt componente, such a~ detergent
builder ~alts, bleach, alkali metal ~ilicates, and the like, i8
substantially increaaed since the preeence of the potassium (K+)
ions requires less water of hydration than the sodium ~Na+~ ions,
such that more water is available to di~solve these salt
compounds. Therefore, all or nearly all of the normally solid
component~ are present dissolved in the aqueous phase. Since
there is none or only a very low percentage, i.e. less than 5~,
preferably less than 3~ by weight, of suspended solids present in
the formulation there is no or only reduced tendency for
undissolved pa~ticles to settle out of the composition~ causing,
for example, formation of hard masses of particles, which could
result in high bottle residue~ (i.e. loee of product).
Furthermore, ~ny undissolved eolids tend to be present in
extremely small particle sizes, ueually colloidal or
sub-colloidal, euch ae 1 micron or lese, thereby further reducing
the tendency for the undissolved particles to eettle. Since
there are ~ubstantially no undiesolved eolid particles of size in
excess of 1 micron, the invention products tend to be transparent
or at least translucent, depending, in part, on air bubble
content.
A still further attribute of the invention compositions
contributing to the overall product stability and low bottle
residue i~ the high water absorption capacity of the cros~-linked
polyacrylictacid-type thickening agent. AB a result of this high
water absorption capacity virtually all of the aqueous vehicle
component appear~ to be held tightly bound to the polymer matrix.
Therefore, there appears to be no or ~ubstantially no free water
13
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. J '~ ~38~2~
present in the invention compositions. Thi~ apparent ab~ence of
free water (as well a~ the cohe~iveness of the compo~ition) i8
manifested by the ob~ervation that when the compoBition i8 poured
from a bottle onto a piece of water ab~orbent filter paper
virtually no water i~ absorbed onto the filter paper over a
period of at least sQveral hours or longer ~nd, furthermore, the
mass of the linear vi~coelastic material poured onto the filter
paper will retain its shape and structurs. A~ a result of the
absence of loosely bound water, there i~ virtually no phase
separation between the aqueou~ pha~e and the polymeric matrix or
di~olved solid particle~. This characteri~tic i~ manifested by
the fact that when the sub~ect compo~itions are ~ub~ected to
centrifugation, e.g. at 1000 rpm for 30 minutes, there is no
pha~e separation and the composition remains homogeneous. The
preferred composltions have remalned stable for periods in excess
of 6 months and more.
In our ~arlier applicatlon Serial No. 07/353,712, it
was stated that to maximize physical (pha~e) stability, the
density of the composition should be controlled such that the
bulk den~ity of the liquid phase i8 approximately the same as the
bulk density of the entire compo~ition, including the polymeric
hickening agent. Thi~ control and equalization of the densitie~
as achieved, according to our earlier invention, by providing
the composition with a bulk density of at least 1.32 g/cc. A
density of about 1.42 g/cc i8 e~sentially equivalent to zero air
content.
It i8 important to note that the bulk density of the
product can be adjusted by ¢ontrolling the degree of aeration, as
well as total solid content. Further, the di~per~ed air bubble~
also contribute to the vi~coela~tic property of the product.
. . . ' . ' , . . ' . , . !. ,
,', . ' ' ' '''" ' " '.. "''' ' :'" ' '.;.. ' ' "' " ,' .
~ Ji~ 3
However, it has now been found that alr bubble
incorporation i~ not required to achisve atabilization and, in
fact, we have been able to prepare ~table thickened product~ with
densities a~ low a~ 1.28 g/cc. At den~itie~ below about 1.28
S c/g, however, the flowability of the product tend~ to be
degraded and the large air bubble content tends to cause the
componition to be too highly tran~lucent or cloudy to opaque.
Therefore, the product density i~ preferably selected in the
range of 1.28 to 1.42 g/cc, especially 1.32 to 1.40 g/cc, and
most preferably from 1.35 to 1.40 g/cc. Within these range~ air
bubble incorporation is determined to achieve the desired product
aesthetic appearance and flow characteristic~.
It h~s previously been found in connection with other
types of thickened aqueous liquid, automatic di~hwasher detergent
compositions that agglomeration or escape of incorporated air
bubbles could be avoided by incorporating certain surface active
ingredients, especially higher fat~y acids and the salts thereof,
such as stearic acid, behenic acid, palmitic acid, sodium
stearate, aluminum stearate, and the like.
Therefore, in the present invention, in order to avoid
stabilization of air bubble~ which may become incorporated into
the compositions during normal proces~ing, ~uch as during various
mixing 6teps, i~ avoided by po~t-adding the eurface active
ingredients to the remainder of the composition, under low shear
condition~ using mixing devices de~igned to minimize cavitation
and vortex formation.
A~ will be described in greater detail below the
surface aative lngredient~ present in the composition will
include the main deteryent surface active oleaning agent, and
will al~o preferably include anti-foaming agent (e.g. phosphate
~3~j
ester) and higher fatty acid or salt thereof a~ a physical
stabilizer.
Exemplary of the polycarboxylate type thickening agent~
are cross-linked polyacrylic acid-type thickening agents eold by
B.F. Goodrich under their Carbopol trademark, including both the
900 serie~ re~in~, e~pecially Carbopol 941, which iB the mo~t
ion-in~ensitive of this cla6s of polymers, and Carbopol 940 and
Carbopol 934, and the 600 series resine, e~pecially Carbopol 614.
The Carbopol 900 series resins are hydrophllia high molecular
weight, cross-linked linear acrylic acid polymers having an
average equivalent weight of 76, and the general structure
illustrated by the following formula:
~ C--C~
HO O n.
Carbopol 941 ha~ a molecular weight of about 1,250,000; Carbopol
940 a molecular weight of approximately 4,000,000 and Carbopol
934 a molecular weight of approximately 3,000,000. The Carbopol
900 series re~ins are cross-linked with polyalkenyl polyether,
e.g. about 1~ of a polyallyl ether of ~ucrose havlng an average
of about 5.8 allyl groups for each molecule of ~ucrose. The
reparation of this cla~s of cro~s-linked carboxylic polymer~ i~
escribed in U.S. Patent 2,798,053, the di~closure of which i~
incorporated by reference. Further detailed information on the
Carbopol 900 seriee resins i~ available from B.F. Goodrich, see,
for example, the B.F. Goodrich catalog GC-67, Carbopo ~ Water
Soluble Resins.
In general, these thickening re~ins are preferably
copolymer~ of a water disper~ible copolymer of an alpha-beta
.: ... - ... .. .. :
,.', ., ~;'' ',' ..',, '', '.. ''.' ,..
. ' : , . '.: '
~ 3
monoethylenically un~aturated lower aliphatic carboxylic acid
cross-linked with a polyether of a polyol ~elected from oligo
saccharide~, reduced derivatives thereof in which the carbonyl
group iB converted to an alcohol group and pentaerythritol, the
hydroxyl groups of the polyol which are modified being etherified
with allyl group~, there being preferably st least two such allyl
groups per molecule.
The~e water-di6per~ible cross-linked thickening resins
as described in the aforementioned U.S. Patent 2,798,053 and
which have been commercialized by B.F. Goodrich a~ the Carbopol
900 series re~ins are prepared from essentially linear
copolymer~. More recently, B.F. Goodrich has introduced the
Carbopol 600 series resin. ~he~e are high molecular weight, non-
linear polyacrylic acid croe~-linked with polyalkenyl ether. In
addition to the non-linear or branched nature of these resin~,
they are also believed to be more highly crc~s-linked than the
900 serie~ resins ant have molecular weights between about
1,000,000 and 4,000,000.
Mo~t e~pecially useful of the Carbopol 600 series
re~ins i~ Carbopol 614 which i8 the most chlorine bleach ~table
of this cla~ of thickening re~ln~. Carbopol 614 is aleo highly
stable in the high alkalinity environment of the preferred liquid
automatic di~hwa~her detergent compositions and i~ also highly
stable to any anticipated ~torage temperature conditions from
below freezing to elevated temperatures a~ high a~ 120F,
preferably 140F, and e~pecially 160F, for period~ of as long
as several days to several week~ or month~ or longer.
While the mo~t favorable results have now been achieved
with Carbopol 614 polyacrylic resin, other linear or branched
cross-linked polycarboxylate-type thicken~ng agents can al~o be
~ 2 ~
used in the composition~ of this invention. A~ u~ed herein
"polycarboxylate-type" refers to water-soluble carboxyvinyl
polymers of alpha,beta monoethylenically un~aturated lower
aliphatic carboxylic acids, which may be llnear or non-linear,
and are exemplified by homopolymers of acrylic acid or
methacrylic acid or water-di~persible or water-soluble salts,
esters or amide~ thereof, or water-soluble copolymers of these
acid~ or their salts, ester~ or amides with each other or with
one or more other ethylenically unsaturated monomers, such a~,
for example, styrene, maleic acid, maleic anhydride,
2-hydroxyethylacrylate, acrylonitrile, vinyl acetate, ethylene,
propylene, and the like, and which have molecular weights of from
about 500,000 ~o 10,000,000 and are cross-linked or
interpolymerized with a multi-vinyl or multl-allylic
functionalized cross-llnking agent, especially with a polyalkenyl
ether of a polyhydric compound.
These homopolymers or copolymers are characterized by
their high molecular weight, in the range of from about 500,000
to 10,000,000, preferably 750,000 to 5,000,000, especially from
about 1,000,000 to 4,000,000, and by their water solubility,
generally at least to an extent of up to about 5~ by weight, or
more, in water at 25C.
These thickening agents are used in their cross-linked
. form wherein the cross-linking may be accomplished by means known
in the polymer arts, as by irradiation, or, preferably, by the
incorporation into the monomer mixture to be polymerized of known
chemical cross-linking monomeric agents, typically
polyunsaturated (e.g. diethylenically unsaturated) monomers, such
as, for example, divinylbenzene, divinylether of diethylene
glycol, N,N'-methylene-bisacrylamide, polyalkenylpolyethers (such
: . . .. . .
.
. .. .. . -.. , . . : -
~ ~ ~ 3 !' ~ r) ',~
as de~cribed above), and the like. Typically, amounts of cros~-
linking agent to be incorporated in the final polymer may range
from about 0.01 to about 5 percent, preferably from about 0.05
to about 2 percent, and especially, preferably from about 0.1 to
about 1.5 percent, by weight of cross-linking agent to weight of
total polymer. Gen~rally, tho~e ~killed in the art will
recognize that the degree of cro~-llnking ~hould be sufficient
to impart some coiling of the otherwi~e generally linear or non
linear polymeric compound while maintaining the cro~s-linked
polymer at least water disper~ible and highly water-swellable in
an ionic aqueous medium.
The amount of the high molecular weight, cross-linked
polyacrylic acid or other high molecular weight, hydrophilic
cros~-linked polycarboxylate thickening agent to ~mpart the
desired rheologlcal property of linear vlscoelasticity will
generally be in the range of from about 0.1 to 2~, preferably
from about 0.2 to 1.4%, by weight, based on the weight of the
composition, although the amount will depend on the particular
cross-linking agent, ionic strength of the compo~Ltion, hydroxyl
donors and the like.
The compositions of this invention must include
sufficient amount of potassium ions and ~odium ions to provide a
weight ratio of K/Na of at lea~t 1:1, preferably from 1:1 to
45:1, especially from about 1:1 to 4~1, more preferably from
1.05:1 to 3:1, such as 1.1:1, 1.2:1, 1.5:1, or 2:1. When the
K/Na ratio i~ less than 1 there 18 insufficient ~olubllity of the
normally solid ingredients whereas when the K/Na ratio iB more
than 45, especially when it is greater than about 3 or 4, the
product becomes too liguid and phase ~eparation begins to occur.
When the K/Na ratios become much larger than 45, such as in an
. - . ' ' .
r most y p~ta~ni~m formulatlon, the polycarboxylate
¦thickener loses it ab~orption capacity and begin~ to salt out of
the aqueou~ phase.
The potassium and sodium ions will be made present in
¦the compositlons a~ the alkali metal cation of the detergent
builder ~alt( B ) ~ aB well as alkali metal silicate or alkali metal
hydroxide components of the compo~itions. The alkali metal
cation may also be present in the composition~ as a component of
¦anionic detergent, bleach or other ionlzable salt compound
¦additive, e.g. alkali metal carbonate. In determining the K/Na
¦weight ratios all of these sources ~hould be taken into
¦consideration.
¦ Spec~fic examples of detergent builder salt~ include
¦the polyphosphates, such a~ alkali metal pyrophosphate, alkali
¦metal tripolyphosphate, alkali metal metaphosphate, and the like,
¦for example, ~odium or potassium tripolyphosphate (hydrated or
¦anhydrous), tetrasodium or tetrapotassium pyrophosphate, sodium
10r potassium hexa-metaphosphate, trisodium or tripotassium
¦orthophosphate and the like, sodium or potassium carbonate,
¦sodium or potas~ium citrate, sodium or potassium
¦nitrilotriacetate, and the like.
¦ In accordance with the present invention, however, the
¦detergent builder salts will be compri~ed of mixtures of at least
potassium tripolyphosphate (KTPP) and ~odium tripolyphosphate
(NaTPP) (e~pecially hexahydrate). Typical ratios of KTPP to
NaTPP are from about 1.4:1 to lOsl, e~pecially from about 2:1 to
8:1. The total amount of detergent bullder salts is preferably
from about 10 to 35~ by weight, more preferably from about 15 to
35%, especially from about 18 to 30~ by weight of the
composition. Of this total amount of the detergent builders at
.:, . .. . . .. , ~ ,,.. ,'.; ,: ,. i ., '
~ 3
lea6t 50~ by weight (preferably at least about 8~ by weight of
the composition3 will be KTPP and preferably at least 5~ by
we.Lght (preferably at lea~t 2~ by weight of the composition) will
be NaTPP. More preferably, the alkali metal detergent builder
salt will be comprised of from about 65 to 95~ of RTPP,
especially 75 to 90% of KTPP and from about 5 to 35%, e~peoially
10 to 25% of NaTPP. In terms of the total compo~ition, the
amount of KTPP will be in the range of from about 8 to 25%,
preferably 15 to 22% by weight, and the amount of NaTPP will be
in the range of from about ~ to 10%, preferably 3 to 8~ by
weight.
When other alkali metal detergent builder ~alts are
present in the'formulation, they will usually be pre~ent in
amounts less than 5~ by welght based on thq total composition
and, in any ca~e, in amounts to maintain the X/Na ratios to
within the above described range, preferably from 1:1.1 to 1:3.
The linear viscoelastic composition~ of thi~ invention
may, and preferably will, contain a small, but stabilizing
effective amount of a long chain fatty acid or monovalent or
polyvalent salt thereof. Although the manner by which the fatty
acid or salt contributes to the rheology and stability of the
compo~ition has not been fully elucidated it iB hypothesized that
it may function as a hydrogen bonding agent or cross-linking
agent for the polymeric thickener.
~5 The preferred long chain fatty acids are the higher
aliphatic fatty aoids having from about 10 to 50 carbon atom~,
more preferably from about 12 to 40 carbon atoms, and especially
preferably from about 14 to 40 carbon atoms, inclusive of the
carbon atom of the carboxyl group of the fatty acid. The
aliphatic radical may be saturated or unsaturated and may be
2 ~
straight or branched. Straight chain saturated fatty acids are
preferred. Mixture~ of fatty acids may be used, such as tho~e
derived from natural ~ource~, such as tallow fatty acid, coco
fatty acid, soya fatty acid, etc., or from synthetic sources
available from industrial manufacturing processes.
Thu~, examples of the fatty acids include, for example,
decanoic acid, dodecanoic acid, palmitic acid, myri~tic acid,
~tearic acid, behenic acid, oleic acid, eicosanoic acid, 'allow
fatty acid, coco fatty acid, soya fatty acid, mixture~ of these
acid~, etc. Stearic acid and mixed fatty acid~, e.g. stearic
acid/palmitic acid, are preferred.
It has, however, also recently been discovered by some
of U8 and othe~s that further improvements in phase stability,
particularly under elevated temperature storage conditions, and
maintenance of product viscosity levels can be obtained by using
longer chain length fatty acids in the range of from Clg to C40.
Either individual or mixture~ of these longer ahain length fatty
acids can be used, however, the average chain length should be in
the range of from about 20 to 32 carbon atoms, especially 24 to
30 carbon atoms and mixture of fatty acids encompassing this
range are preferred. Sultable mixed fatty ac~ds are commeraially
available, for instance those sold under the trade name Syncrowax
by Croda.
When the free acid form of the fatty acid is used
directly it will generally associate with the potassium and
sodium ions in the aqueous phase to form the corresponding alkali
metal fatty acid soap. However, the fatty acid salts may be
direatly added to the composition as sodium salt or potassium
salt, or as a polyvalent metal salt, although the alkali metal
salts of the fatty acids are preferred fatty acid salts.
" ''' ' , '- ' :- ' - ,
The preferred polyvalent metals are the di- and tri-
valent metals of Groups IIA, II~ and III~, such as magnesium,
calcium, aluminum and zinc, although other polyvalent metals,
including those of GroupB IIIA, IVA, VA, IB, IVB, VB, VI~, VIIB
and VIII of the Periodic Table of the Elements can also be used.
Specific examples of such other polyvalent metals include Ti, Zr,
V, Nb, Mn, Fe, Co, Ni, Cd, Sn, Sb, Bi, etc. Generally, the
metal~ may be present in the divalent to pentavalent state.
Preferably, the metal ~alts are used in their higher oxidation
~tates. Naturally, for use in automatic dishwashers, as well a~
any other applications where the invention compo~ition will or
may come into contact with article~ used for the handling,
storage or ser~ing of food products or which otherwise may come
into contact with or be consumed by people or animals, the metal
salt should be selected by taking into consideration the toxicity
of the metal. For this purpose, the alkall metal and calcium and
magnenium salts are especially higher preferred a8 generally safe
food additives.
The amount of the fatty acid or fatty acid salt
stabilizer to achieve the desired enhancement of physical
stability will depend on such factors as tha nature of the fatty
cid or its salt, the nature and amount of the thickening agent,
etergent active compound, inorganic salts, other ingredients, as
ell as the anticipated storage and shipping conditions.
Generally, however, amounts of the fatty acid or fatty
acid salt stabilizing agente in the range of from about 0.02 to
2%, preferably 0.04 to 1%, more preferably from about 0.06 to
0.8%, especially preferably from about 0.08 to 0.4%, provide a
long term stability and ab~ence of phase separation upon standing
. ,.. . . . . - - :
.
:' ' ' "," :" - ' ' ' ' '' .''
~ Q~
or during transport at both low and elevated temperatures as are
required for a commercially acceptable product.
Depending on the amounte, proport~one and types of
fatty acid phy~ical stabilizers and polycarboxylate thickening
agent#, the addition of the fatty acid or ealt not only increases
physical etability but also provides a simultaneou~ increase in
apparent viscosity. Amounts of fatty acid or salt to polymeric
thickening agent in the range of from about 0.08-0.4 weight
percent fatty acid salt and from about 0.4-1.5 weight percent
polymeric thlckening agent are u~ually euffic~ent to provide
these simultaneous benefits and, therefore, the u~e of these
ingredients in these amountB i8 moet preferred.
In order to achieve the deeired benefit from the fatty
acid or fatty acid ealt stabilizer, without stabil~zation of
excess incorporated air bubbles and consequent excessive lowering
of the product bulk den~ity, the fatty acid or ealt iB preferably
poet-added to the formulation, preferably together with the other
surface active ingredients, including detergent active compound
and anti-foamLng agent, when present. Theee eurface active
ingredients are preferably added ae an emulsion in water wherein
the emulsified oily or fatty materiale are finely and
homogeneously disper13ed throughout the aqueous phase. To achieve
the desired fine emulsification of the fatty acid or fatty acid
ealt and other surface active ingredients, it ie usually
necessary to heat the emul~ion (or preheat the water) to an
elevated temperature near the melting temperature of the fatty
acid or its salt. For example, for stearic acid having a melting
point of 68-69C, a temperature in the range of between 50C and
70C will be used. For lauric acid (m.p.~47C) an elevated
temperature of about 35 to 50C can be used. Apparently, at
.;. : ... . . . ' , .
~ 3g~
these elevated temperatures the fatty acid or ~alt and other
surface active ingredients can be more readily and uniformly
dl~per~ed (emul~ified) in the form of fine droplets throughout
the composition.
Foam inhibition i~ important to increase dishwa~her
machine efficiency and minimize destabilizing effects which
might occur due to the pre~ence of exces~ foam within the washer
during use. Foam may be reduced by suitable selection of the
type and/or amount of detergent active material, the main foa~-
producing component. The degree of foam i~ also somewhat
dependent on the hardne~s of the wash water in the machine
whereby ~uitable adjustment of the proport~ons of the builder
galts, such as NaTPP which has a water softening effect, may aid
in providing a degree of foam inhibltion. However, it is
generally preferred to include a chlorine bleaah stable foam
depre~sant or inhibitor. Particularly effective are the alkyl
phosphoric acid e8ters of the formula
O
and especially the alkyl acid phosphate esters of the formula
HO P---OR
OR
In the above formulas, one or both R groups in each type of ester
may represent independently a C12-C20 alkyl group. The
ethoxylated derivative~ of each type of ester, for example, the
condensation products of one mole of e~ter with from 1 to 10
mole~, preferably 2 to 6 moles, more preferably 3 or 4 moles,
ethylene oxide can al80 be used. Some examples of the foregoing
~ J
are commercially available, such a~ the products SAP from Hooker
and LPKN-158 from Rnapsack. Mixture~ of the two types, or any
other chlorine blea¢h etable types, or mixture~ of mono- and di-
e~ters of the ~ame type, may be employed. E~pecially preferred
in a mixture of mono- and di-C15-C18 a}kyl ac~d pho~phate e~ter~
such as monostearyl/distearyl acid phosphate~ 1.2/l, and the 3 to
4 mole ethylene oxide aondensates thereof. When employed,
proportions of 0.05 to 1.5 weight percent, preferably 0.1 to 0.5
weight percent, of foam depressant in the composition is typical,
the weight ratio of detergent active component (d~ to foam
dep-essant (e) generally ranging from about 10:1 to 1:1 and
preferably about 5:1 to 1:1. Other defoamers which may be used
include, for ~xample, the known silicones, such as available from
Dow Chemicals. In addition, it i~ an advantageous feature of
this ~nvention that many of the stabilizing salts, such as the
stearate salts, for example, aluminum etearate, when included,
are also effective as foam killers.
Although any chlorine bleach compound may be employed
in the compositions of this invention, such as dichloro-
i~ocyanurate, dichloro-dimethyl hydantoin, or chlorinated TSP,
alkali metal or alkaline earth metal, e.g. potassium, lithium,
magnesium and especially sodium, hypochlorite is preferred. The
compo~ition should contain sufficient amount of chlorine bleach
compound to provide about 0.2 to 4.0% by weight of available
chlorine, as determined, for example, by acidification of 100
parts of the composition with excess hydrochloric acid. A
~olution containing about 0.2 to 4.0~ by weight of sodium
hypoahlorite contain~ or provides roughly the same percentage of
available chlorine. About 0.8 to 1.6% by weight of available
chlorine is especially preferred. For example, sodium hypo-
:. . . :
: ::
chlorite (NaOCl) 80Iution of from about 11 to about 13~a~ailable chlorine in amounts of about 3 to 20%, preferably about
7 to 12~, can be advantageously used.
Another surprising and unexpeeted benef it and advantage
of the preferred Carbopol thiekened eompo~itions of thi~
invention is the essentially total masking of any chlorine bleach
odor which i8 eharacteristic of, for example, the prior known
clay thickened produet~. By virtue of the masking of chlorine
bleach odor, it has been found that the ~ubjeet eompositions can
be blended with ~ubstantially lower amounts of fragranee, e.g.
lemon oil fragranee, to aehieve the same or superior olfaetory
sensation for the consumer. For instanee, as little as 0.05~ of
lemon fragrance will have the ~ame effect as about 0.12% in clay
thiekened produets.
Furthermore, the addition of fragranee does not
adversely affeet the stability criteria, as previously defined,
such a~ viscosity or phase ~tability, of the compo~itions.
Detergent active material useful herein ~hould be low-
foaming and stable in the presence of ehlorine bleaah, when
pre~ent, especially hypoehlorite bleaeh, and for thi~ purpose
those of the organic anionie, nonionic, amine oxide, phosphine
oxide, sulphoxide or betaine water dispersible surfaetant types
are preferred, the first mentioned anionies being most preferred.
Partieularly preferred ~urfaetants herein are the linear or
branched alkali metal mono- and/or di-(Cg-C14) alkyl diphenyl
oxide mono- and/or di-sulphates, eommereially available for
example as DOWFAX (registered trademark) 3B-2 and DOWFAX 2A-l.
In addition, the surfactant should be eompatible with the other
ingredient6 of the composition. Other suitable organic anionic,
: ;: ' . . '".' ',' ' - . '.. '
- ~ 2~3~
on-soap surfactants include the primary alkylsulphate~,
alkylsulphonate~, alkylarylsulphonates and
sec.-alkylsulphates. Examples include sod~um Clo-Clg
lkyl6ulphates such as sodium dodecylsulphate and sodium tallow
5 lcoholsulphate; sodium Clo-Clg alkanesulphonates such as sodium
exadecyl-l-~ulphonate and sodium C12-Clg alkylbenzenesulphonate~
such as ~odium dodecylbenzenesulphonates. The corresponding
otas~ium salts may also be employed.
AB other sultable surfactants or detergents, the amine
xide surfactants are typically of the structure R2RlN0, in
hich each R represents a lower alkyl group, for instance,
ethyl, and Rl repre~ents a long chain alkyl group having from 8
o 22 carbon a~oms, for instance a lauryl, myristyl, palmityl or
etyl group. Instead of an amine oxide, a corresponding
surfactant phosphine oxide R2RlP0 or sulphoxide RRlS0 can be
mployed. Betaine surfactant~ are typi¢ally of the structure
2RlN~R"C00-, in which each R repre~ent~ a lower alkylene group
having from 1 to 5 carbon atoms. Specific examples of these
surfactants include lauryl-dimethylamine oxide, myri~tyl-
dimethylamine oxide, the corre~ponding phosphine oxides andsulphoxide~, and the corresponding betaine~, including
dodecyldimethylammonium acetate, tetradecyldiethylammonium
pentanoate, hexadecyldimethylammonium hexanoate and the like.
For biodegradability, the alkyl groups in these surfactants
should be linear, and such compounds are preferred.
Surfactant~ of the foregoing type, all well known in
the art, are describedr for example, in U.S. Patents 3,985,668
and 4,271,030. If chlorine bleach is not u~ed than any of the
well known low-foaming nonionic surfactants such as alkoxylated
. , :, .~ . .'. . '. ,: .'
.
~ ~ 2~3~ 3
fatty alcohols, e.g. mixed ethylene oxide-propylene oxide
condensate~ of C8-C22 fatty alcohols can also be u~ed.
The chlor~ne bleach stable, water disper~ible organic
detergent-active material ~surfactant) will normally be pre~ent
in the composition in minor amounts, generally about 1~ by weight
of the composition, although smaller or larger amount~, such a~
up to about 5%, such as from 0.1 to 5%, preferably from 0.3 or
0.4 to 2% by weight of the composition~ may be used.
Alkali metal (e.g. potassium or sodium) silicate, which
provides alkalinity and protection of hard surfaces, such as fine
china glaze and pattern, i8 generally employed in an amount
ranging from about 5 to 20 weight percent, preferably about 5 to
15 weight perdent, more preferably 8 to 12% in the composition.
The sodium or potassium silicate i~ generally added in the form
of an aqueous solution, preferably having Na20sSiO2 or ~20:SiO2
ratio of about 1:1.3 to 1:2.8, especially preferably 1:2.0 to
1:2.6. At this point, it ehould be mentioned that many of the
other components of this compositlon, especially alkali metal
hydroxide and bleach, are also often added in the form of a
preliminary prepared aqueous dispersion or solution. However,
unles~ otherwise noted, when amount3 of a particular ingredient
are given, the reference iB to an active ingredient basis, i.e.
does not include the aqueous carrier.
In addition to the detergent active surfactant, foam
inhibitor, alkali metal silicate corrosion inhibitor, and
detergent builder salt~, which all contribute to the cleaning
performance, it is also known that the effectiveness of the
liquid automatic dishwasher detergent compo~itions is related to
the alkalinity, and particularly to moderate to high alkalinity
levels. Acaordingly, the compositions of this invention will
~ '- 21~3~
have pH values of at least about 9.5, preferably at least about
11 to as high as 14, generally up to about 13 or more, and, when
added to the aqueoua wash bath at a typical concentration level
of about 10 grams per liter, will provide a p~ in the wash bath
of at least about 9, preferably at least about lOt such as 10.5,
11, 11.5 or 12 or more.
The alkalinity will be achieved, in part, by ths alkali
metal ion~ contributed by the alkali metal detergent builder
~altc, e.g. sodium tripolyphosphate, potassium tripolyphosphate,
and alkali metal silicate, however, it i8 usually necessary to
include alkali metal hydroxide, e.g. NaOH or ROH, to achieve the
desired high alkallnity. Amounts of alkal~ metal hydroxide in
the ranqe of from about 0.5 to 8%, preferably from 1 to 6~, more
preferably from about 1.2 to 4%, by weight of the compo~ition
will be sufficient to achieve the desired pH level and/or to
adjust the K/Na weight ratio.
While as stated above, high alkalinity is desired with
regard to improved cleaning performance, it has now additionally
been discovered that the pH of the composition during processing
is highly important for product stability, e.g. viscosity, and
bleach stability and phase stability. Specifically, it has been
found that, e~pecially for the Carbopol clsss of thickening
agents, the amount of basic neutralizing agent, preferably NaOH,
should be sufficient to provide the neutralized thickening agent
with a pH of at least 11, preferably at lea~t 11.5. Furthermore,
these high alkallnity level~ should be mslnts~ned throughout the
product formulation steps, namely, the pH value of at lea~t 11,
preferably at least 11.5, should be maintained during the
successive additions of the other ingrediente of the composition.
~ 3
AB will be shown by the examples given below, if the pH
rop~ to a lower value, there 18 a 10~8 in vi~cosity, a~ well as
stability (as manifested by liqu~d phRse separation) over time.
Other alkali metal ~alt~, ~uah a~ alkali metal
carbonate may also be present ~n the composition~ ln minor
amounts, for example from O to 4%, preferably O to 2%, by weight
of the composition.
Another often beneficial additive for the pre6ent
liquid automatic dishwasher detergent compo~itions is a
relatively low molecular weight, non-crosslinked polyacrylic
acid or neutralized with cau~tic, such a8 the commercial product
Acrysol LMM-45N, which has a molecular welght of about 4,500.
The low m.w. polyacrylic acids can provide additional thickening
characteristics but are primarily introduced for their ability to
function as a builder or chelating agent. In this capacity, the
low m.w. polyacrylic acids can aontribute to reduced spotting or
streaking and reduced filming on di~hes, glas~ware, pots, pans,
and other utensil~ and appliances.
Generally, a suitable molecular weight ranges for the
non-cros~linked polyacrylic acid 18 from nbout 800 to 200,000,
preferably 1000 to 150,000, especially from about 2,000 to
100,000. When present in the formulat~on, the non-crosslinked
polyacrylic acid can be used in amounts up to about 10% by
weight, preferably from about 1 to 8% by weigbt, especially 2 to
6% by weight of the composition.
Other conventional ingredients may be ~ncluded in these
compositions in small amounts, generally les~ than about 3 weight
percent, ~uch as perfume, hydrotropic agents such as the sodium
benzene, toluene, xylene and cumene ~ulphonAtes, preservatives,
dyestuffs and pigments and the like, all of course being stable
;'" . ," '.'. '. ' '''. ' ", , '. .
o chlorine bleach compound and high alkalinity. E~pecially
referred for coloring ara the chlorinated phthalocyaninea and
olysulph~de~ of alumino~ilicate which provide, respectively,
lea~ing green and blue tint~. To achieve ~table yellow colored
roducts, the bleach stable mixed dyes C.I. Direct Yellow 28
(C.I. 19555) or C.I. Direct Yellow 29 (C.I. 195S6) can be added
o the compositions. These colors meet stability criteria
escribed in Table A. Tio2 may be employed for whitening or
eutralizing off-shades.
Although for the reasons previously discu~ed excessive
ir bubbles are not often desirable in the invention
ompositions, depending on the amounte of di~olved solids and
liquid phase densitie~, incorporation of small amount~ of finely
divided air bubbles, generally up to about 10% by volume,
preferably up to about 4% by volume, more preferably up to about
2~ by volume, can be incorporated to adjust the visual
appearance, product density and flowability. The incorporated
air bubbles should be finely divided, such as up to about 100
¦microns in diameter, preferably from abou~ 20 to about 40 microns
in diameter. Other inert gases can also be used, such as
nitrogen, carbon dioxide, helium, oxygen, etc.
The amount of water contained in the~e compositions
should, of course, be neither 80 high as to produce unduly low
viscosity and fluidity, nor 80 low as to produce unduly high
vis¢osity and low flowability, linear viscoelastic properties in
either oase being diminished or de~troyed by increasing tan
1. Such amount is readily determined by routine experimentation
in any particular instance, and generally will range from 30 to
5 weight percent, preferably about 35 to 65 weight percent.
Preferably, the watex should also be deionized or softened.
., ' , ' "..' -- .', .
. 2 ~
The manner of formulating the invention componitions i8
l~o important. AB di~cu~ed above, the order of mixing the
ngredient~ a~ well as the manner in which the mixing iB
erformed will generally have a signiflcAnt effect on the
roperties of the composition, and in particular on product
ensity, (by incorporation of more or less air), viscosity and
hysical ~tability (e.g. phase separation). Thus, according to
he preferred practice of this invention the compositions are
repared by forming a di~persion of the polycarboxylate type
hickener in heated water, e.g. 35 to 60C (95 to 140F),
referably 40~ to 50C (104 to 122F), under moderate to high
shear conditions, neutralizing the di~solved polymer to a pH of
t least 11, preferably at least 11.5, such a~ from 11.5 to 13.0,
to cau6e gelation. After transferring the thickener dispersion
to a main mixing tank processing 1B continued by introducing,
while continuing mixing, the detergent builder salts, alkali
jmetal silicatee, chlorine bleach compound and remaining detergent
additive~, including any previously unu~ed alkali metal
hydroxide, if any, other than the surface-active compounds. All
of the additional ingredient~ can be added simultaneously or
~equentially. Preferably, the ingredient~ are added
sequentially, with mixing continued for from 2 to 10 minute~ for
each ingredient, although it iB not neces~ary to complete the
addit~on of one ingredient before beginning to add the next
ingredient. Furthermore, one or more of the~e ingredient~ can be
divided into portions and added at different times. These mixing
steps should al~o be performed under moderate to high shear rates
to achieve complete and uniform mixing. These additional
ingredient mixing eteps may be carried out at room temperature,
but preferably the elevated temperature of the thickener ~lurry
; : '. . ' - ' . ' ' :
2038~2~
i8 maintained. The compo~ition may be allowed to age, if
neces~ary, to cause dissolved or di~persed air to dis~ipate out
of the composition.
The remaining surface active ingredients, including the
anti-foaming agent, organic detergent compound, and fatty acid or
fatty acid salt stabilizer is post-added to the previou~ly formed
mixture in the form of an aqueous emulsion (using from about 1 to
10%, preferably from about 2 to 4% of the total water added to
the composition other than water added a~ carrier for other
ingredients or water of hydration) which is pre-heated to a
temperature in the range of from about Tm-5 to Tm+20, preferably
from about ~m to Tm+10, where ~m is the melting point temperature
of the fatty acid or fatty acid salt. For the stearic acid
~tabilizer the heating temperature is in the range of 150 to
170F ~65 to 77C). For the high chain length fatty acid~ and
mixtures Cl~-C36, correspondingly higher temperatures may be
used, such as from about 160 to 200F ~ca. 70 to 95C).
However, if care i8 taken to avoid excessive air bubble
incorporation during the gelation step or during the mixing of
the detergent builder salts and other additives, for example, by
operating under vacuum, or using low shearing conditions, or
special mixing apparatus, etc., the order of addition of the
surface active ingredients should be less important.
In accordance with an especially preferred embodiment,
the thickened linear viscoelastic aqueous automatic dishwasher
detergent composition of this invent~on ~nclude~, on a weight
basis:
(a)(i) 8 to 25%, preferably 10 to 20%, potassium
ripolyphosphate detergent builder;
- - 20~2~ ~
(ii) 2 to 10~, preferably 4 to 8%, sodium
ripolypho~phate detergent builder, at an (i)/(ii) weight ratio
f from about 1.4/1 to 10/1, preferably 2/1 to 6/1;
(b) 5 to 15, preferably 8 to 12%, alkali metal
silicate;
(c) 1 to 6%, preferably 1.2 to 4%, alkali metal
ydroxide;
(d) 0.1 to 3%, preferably 0.5 to 2%, chlorine bleach
~table, water-disper~ible, low-foaming organic detergent active
material, preferably non-soap anionic detergent;
(e) 0.05 to 1.5%, preferably 0.1 to 0.5%, chlorine
bleach stable foam depressant;
(f~chlorine bleach compound in an amount to provide
about 0.2 to 4%, preferably 0.8 to 1.6%, of available chlorine;
(g) non-linear, water-di~persible polyacrylic acid
thickening agent comprising at least one high molecular weight
hydrophilic polycarboxylate having a molecular weight of from
750,000 to 4,000,000, preferably 800,000 to 3,000,000, in an
amount to provide a linear vi~coelasticity to the formulation,
referably from about 0.2 to 2%, e~pecially preferably from about
0.4 to 1.5%, more preferably from about 0.4 to 1.0%;
(h) a long chain fatty acid or a metal ~alt of a long
hain fatty acid in an amount effective to Lncrease the phy~ical
~tability of the aompositions, preferably from 0.08 to 0.4%, more
preferably from 0.1 to 0.3%; and
(i) 0 to 10%, preferably 1 to 8~, especially 2 to 6%
of non-cros~linked polyacrylic acid having a molecular weight in
the range of from about 8Q0 to 200,000, preferably 1000 to
150,000, especially 2,000 to 100,000; and
: ' , ',. , ~' . .
- 2 ~ 2 ~
(j) balance water, preferably from about 30 to 75%,
ore preferably from about 35 to 65%; and wherein in the entire
omposition the ratio, by weight, of potassium ion~ to ~odium
OIIB iB from about 1.05/1 to 3/1 or 4/1, preferably from 1.1/1 to
2.5/1. The composltions may also have an amount of air
ncorporated therein such that the bulk density of the
omposition is from about 1.28 to 1.42 g/c¢, preferably from
bout 1.32 to 1.42 g/cc, more preferably from about 1.35 to 1.40
/cc.
The compositions will be supplied to the consumer in
suitable di~penser containers preferably formed of molded
lastic, e~pecially polyolefin plastic, and most preferably
paque or tra~slucent polyethylene, for which the invention
ompositions appear to have particularly favorable ~lip
characteri~tice. In addition to their linear viscoelastic
character, the compositions of thi~ invention may also be
characterized a~ pseudoplastic gels (non-thixotropic) which are
typically near the borderline between liquid and solid
viscoelastic gel, depending, for example, on the amount of the
olymeric thickener. The invention composition~ can be readily
oured from their containers without any shaking or squeezing,
i.e. have a sufficiently low yield stress value to flow under
their own weight (gravity), although squeezable containers are
often convenient and accepted by the consumer for gel-like
product~.
The liquid aqueous linear viscoelastic automatic
i~hwa~her composition~ of this invention are readily employed in
known manner for washing dishes, other kitchen utensils and the
like in an automatic di~hwasher, provided with a suitable
¦¦dotergent dL~ en~er, ln an aqueou~ waoh bath conta1n1ng an
- . : ., . ., .:-
.. . . . .
'- 2~3~
ffective amount of the compo~ition, generally sufflcient to fill
r partially fill the automatic dispenser cup of the particular
achine being used.
The invention also provides a method for cleaning
ishware in an automatic dishwashing machine with an aqueou~
a~h bath containing an effective amount of the liquid linear
iscoelastic automatic dishwa~her detergent composition as
escribed above. The composition can be readily poured from the
olyethylene container with little or no squeezing or ~haking
into the dispensing cup of the automatic dishwashing machine and
will be sufficiently viscous and cohesive to-remain ~ec~rely
within the dispensing cup until ~hear forces are again applied
thereto, such'a~ by the water ~pray from the di~hwa~hing machine.
The invention may be put into practice in varioue way~
and a number of specific embodiments will be described to
illustrate the invention with reference to the accompanying
examples.
All amounts and proportions referred to herein are by
¦weight of the compo~ition unle~s otherwise indicated.
¦Exam~le 1
The following formulations A-F were prepared a~
escribed below:
37
2~3~23
I u~ I 1~ I ~
~ o~ I I ~ ~ C4 ,, , ,, l o
~ 1' l ~ I' ~ 1 1 I o ~ l
I l~u l~o
~: a~ Lt~ .CO CO _l _l ~1 O ~
1' l ~ I' ~ o o 1
l U~ ~D 1~, lo
cl: o~ o a~ ~ ~ co _~ I ,~ r~ O
, ~ 1~' ~ ~r ~ l o~ In 1~
.al ~ o~ m ~. u) ~o ~o ~1 ~1 o
E~ ~ C l l o ~ ~ l ~ u~ o o c ~1 O
f~ a~ u~ _l In ~ a~ ,1 -ol ,, o
m c l o l ~r N _1 l _1 O -I l~ ~ l
. I¢ o~ ~r _1 1~') ~ _~ _1 ~`I _l l
. .. . . . . ..... . . .
! ': ', . . . , - ' ' . . ~ ' . ' . . , ' ' .
`- - 203~3
U~ U~ U~ I I
m. 1~ ~ ~ g I I I
1~ ~ ~r ~r ~ Z
t.q u~ u~ u~ ul
o ¦ OD 3 !~ l ¦ H
JJI o~l ~ ~ ~ ~ I 1~
il ~
a,~ 1_ ~ 3 Pl
m I o ~1 a~ ~ l l ~-
I ~ ~ un~0
1, , ., ",. , . . ' .,' ' '.'
~: ' :.' ,,, " : ,
. ~.. :, . :, . .
'- 2 ~ i
Formulations A, B, C, D, E and F are prepared by fir~t
forming a uniform di~per~ion of the Carbopol 614 or 940 thickener
in about 97% of the water of the total formula water. The
Carbopol is slowly added by sprinkling it into the vortex of
previously colored deionized water preheated to a temperature of
105F u~ing a mixer equipped with a premier blade, with agitation
set at a medium shear rate, a~ recommended by the manufacturer.
After mixing for about 15 minutes, the dispersion i~ then
neutralized by addition, under the ~ame mixing, of the cau~tic
~oda (50% NaOH) componsnt until a thickened product of gel-like
con~istency is formed ~about 10 minutes).
To the resulting gelled dispers~on the silicate, sodium
tripolypho~phate (NaTPP), tetrapota~sium pyrophosphate (TKPP), or
pota~sium tripolyphosphate (KTPP), the surfactant emulsion
~described below) and bleach and ¢olor, are added ~equentially,
in the order stated, with the mixing continued at medium shear
for several minutes before adding the next ingredient. After the
addition of the surfactant emulsion ~at 160F), the mixture i~
cooled to from 90-95F before the bleach i~ added.
Separately, the surfactant emulsion of the phosphate
anti-foaming agent (LPKN), ~teario acid or fatty acid mixture and
etergent (Dowfax 3B2) is prepared b~ adding the~e ingredients to
the remaining 3~ of water and heating the resulting mixture to a
temperature in the range of 160~ (71C). In formulation E, the
~cry601 LMM 45-N may be added at this stage.
The rheograms for the formulations A, ~, C, D, ~ and F
are ~hown in figures 1-6, respectively.
These rheograms are obtained with the System 4
Rheometer from Rheometrics eguipped with a Flu~d Servo with a 100
grams-centimeter torque transducer and a 50 millimeter parallel
~ 40
2 ~ 2 ~
late geometry having an 0.8 millimeter gap between plates. All
easurements are made at room temperature (25~1C) in a humidity
hamber after a 5 minute or 10 minute holding per~od of the
eample in the gap. The measurements are made by applying a
frequency of 10 radians per second.
All of the compo~ition formulations C, D and F exhibit
linear viscoelasticity as seen from the rheograms of figure 2-6.
No phase separation at from ambient temperature to 140F were
ob~erved for any of the formulations for at least the minimum
number of week~ required to satisfy the criteria ~tability as
shown in Table A above. Formulations E and F were still being
tested when this application was filed.
However, in the control formulations A and B maintained
at 100F, the TKPP crystallized in the aqueous phase and
eventually formed ~ufficiently large size crystal~ which
separated to the bottom of the composition. Also, as seen in
figures 1 and 2 formulatione A and B are not linear vi~coela~tic,
at leaet within the preferred criteria a~ previously described.
Formulations C, D, E and F, according to the invention did not
ndergo any crystal growth.
For the bottle residue test, each formulation is
llowed to age for about 1 week at amb~ent temperature in a
standard 32 ounce small necked polyethylene bottle. An amount of
roduct is poured from the bottle to fill a standard ~ized
i~pen~er cup of an automatic di~hwasher. The bottle is then
replaced in an upright position and i~ retained in the upr~ght
position for at least 15 minutes. This procedure of filling the
diffpen~er cup, placing the container in the upright position and
waiting at least 15 minutes is repeated until no more product
. . . . ...
'.' , .''. ,' '-
. . ~3~^3~2~
low~ from the bottle. At thi~ time, the weight o~ the bottle i~
easured. Bottle residue iB calculated a
Wf x100
Wo
5 O i8 the initial weight of the filled bottle and ~f iB the final
eight of the filled bottle. The bottle renidue for each
formulation A-F i8 about 4 to 5%. ~ormulations C-F have
i~co~itie~ of from 10,000 to 20,000 mea~ured with a Brookfield
LVT viscometer, ~4 spindle at 20 rpm mea~ured at 80F. all of
he~e product~ are ea~ily pourable from the polyethylene bottle.
ExamPle 2
A Carbopol 614 ~lurry i~ formed a~ described in Example
1 except that,the coloring agent i~ fir~t added to the deionized
ater (about 92% of the total added water) and the amount~ of the
ingredient~ are changed a~ shown below. The premix (~urfactant
emul~ion) of the surface actlve ingredients is al~o formed as in
Example 1 using stearic acid a~ the fatty acid stabilizer and the
remaining 8% of the total added water.
The ingredient~ are then mixed together with the
Carbopol 614 ~lurry in the following order~ alkali metal
silicate, NaTPP (powder), RTPP (powder), ~urfaatant emulsion,
bleach and perfume. The reHulting compo~ition i~ obtained with
the following ingredient~ in the following amounts:
Inaredient Amount (wt%~
eionized Water q.~.l00
arbopol 614 1.00
aOH (38~Na2O~ 6.38
Na ~ilicate (1:24)(47.5S) 20.83
KTPP (anhydrou~)powder 20.35
aTPP (3% H2O)powder 5.26
owfax 3B2 0.80
LPRN 0.16
Stearic Acid 0.15
~leach (Na hypochlorite-13%) 9.23
CI Pigment Green 7 (CI 74260) 0.0024
Highlights (fragrance) 0.05
.: ' ,: ' . . ,
203go2~ ~
The compoBition has a pH of 11-3 ~ 0.2 and density
(~p.gr.) of 1.39 + 0.03. The vlsco~ity at 80F measured with a
Brookfield LVT viscometer at 20 rpm with a #4 spindle i~
12,000 + 2,000.
S All of the preferred criterla as set forth in Table A
above are sati~fied.
43
' ' ' ' .. ' . . ,, ., .: -
. . . .. -
