Note: Descriptions are shown in the official language in which they were submitted.
2~7~
IR-4681N
LINEAR VISCOELASTIC AQUEOUS
~IQUID AUTOMATIC DISHWASHER
DETERGENT COMPOSITION
Backqround of the Invention
Liquid automatic dishwasher detergent compositions, both
aqueous and nonaqueous, ha~e recently received much attention,
and the aqueous products have achieved commercial popularity.
The acceptance and popularity of the liquid formulations
as compared to the more conventional powder products stems
from the convenience and performance of the liquid products.
However, even the best of the currently available li~uid
formulations still suffer from two major problems, product
phase instability and bottle residue, and to some extent cup
leakage from the dispenser cup of the automatic dishwashing
machine.
Representative of the relevant patent art in this area,
mention i9 made of 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
4,07g,015; ~eikhem, U.S. Patent 4,116,849; Milora, U.S. Patent
4,521,332; ~ones, U.S. Patent 4,597,889; Heile, U.S. Patent
4,512,908; Laitem, U.S. Patent 4,753,748; Sabatelli, U.S.
Patent 3,579,455; Hynam, U.S. Patent 3,684,722: other patents
relating to thickened detergent compositions include U.S.
Patent 3,9a5,668; U.K. Patent Applications GB 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.);
2 0 7 ~
U.S. Patent 4,801,395 (Drapier, et al.). Commonly assigned
co-pending patents include, for example, Serial No. 204,476
filed ~une 9, 1988; Seriai No. 92~,385, filed October 29,
1986; Serial No. 323,138, filed March 13~ 1989; Serial No.
087,836, filed August 21, 1987; 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 present invention provides a solution to the above
problems.
~rief_Description of the Drawings
Figures 1-13 are rheograms, plotting elastic modules G'
and viscous modulus G" as a function of applied strain, for
the compositions of Example 1, Formulations A, C, D, G, ~, H,
I and K, Example 2, A and B, Example 3, L and M and
Comparative Example 1, respectively.
Summary of the Invention
According to the present invention there is provided a
novel aqueous liquid automatic dishwasher detergent
composition. The composition is characterized by its linear
viscoelastic behavior, substantially indefinite stability
against phase separation or settling of dissolved or suspended
particles, low levels of bottle residue, relatively high bulk
density, substantial absence of unbound or free water, and
that the composition will not adhere onto the interior surface
of a polyolefinic bottle. This unique combination of
properties is achieved by virtue of the incorporation into the
~rl~D~3~.
aqueous mixture of dishwashing detergent surfactant, alkali
metal deteryent builder salt(s) and chlorine bleach compound,
a small but effective amount of a polymeric thickening agent
such aæ a high molecular weight cross-linked polyacrylic acid
type thickening agent, a physical stabilizing amount of a long
chain fatty acid or salt thereof, and a source of potassium
ions to provide a potassium/sodium weight ratio in the range
of from 1:1 to 45:1, such that substantially all of the
detergent builder salts and other no~mally solid detergent
additives present in the composition are present dissolved in
the aqueous phase. The compositions are further characterized
by a bulk density of at least 1.28 g/cc, such that the
density of the polymeric phase and the density of the aqueous
(continuous) phase are approximately the same.
Detailed Description of the Preferred Embodiments
The compositions of this invention are aqueous liquids
containing various cleansing active ingredients, detergent
adjuvants, structuring and thickening agents and stabilizing
components, although some ingredients may serve more than one
of these functions.
The advantageous characteristics of the compositions of
this invention, including physical stability, low bottle
residue, high cleaning performance, e.g. low spotting and
filming, dirt residue removal, and so on, and superior
aesthetics, are believed to be attributed to several
interrelated factors such as low solids, i.e. undissolved
particulate content, product density and linear viscoelastic
rheology as well as a means for preventing the composition
from wetting and adhering to the interior surface of a
polyolefinic bottle. These factors are, in turn, dependent on
several critical compositional components of the formulations,
namely, (1) the inclusion of a thickening effective amount of
polymeric thickening agent having high water absorption
capacity, exemplified by high molecular weight cross-linked
polyacrylic acid, (2) inclusion of a physical stabilizing
amount of a long chain fatty acid or salt thereof, (3)
potassium ion to sodium ion weight ratio K/Na in the range oE
from 1:1 to ~5:1, especially from 1:1 to 3:1, and (4) a
product bulk density of at least 1.28 g/cc, such that the
bulk density and liquid phase density are the same.
The polymeric thickening agents contribute to the linear
viscoelastic rheology of the invention compositions. As used
herein, "linear viscoelastic "or" linear viscoelasticity"
means that the elastic (storage) moduli (G') and the viscous
(109s) moduli (G") are both substantially independent of
strain, at least in an applied strain range of from 0-50%, and
preferably over an applied strain range of from 0-80~. More
specifically, a composition is considered to be linear
viscoelastic for purposes of this invention, if over the
strain range of 0-50~ the elastic moduli G' has a minimum
value of 100 dynes/sq.cm., preferably at least 250
dynes/sq.cm., and varies less than 500 dynes/sq.cm,
preferably less than 300 dynes/sq.cm., especially preferably
less than 100 dynes/sq.cm. Preferably, the minimum value of
G' and maximum variation of G' applies over the strain range
~7~
o~ 0 to 80~. Typically, the variation ln loss moduli G" will
be less than that of G'. As a further characteristic of the
preferred linear viscoelastic compositions the ratio of G"/G
(tanS) is less than 1, preferably less than 0.8, hut more than
0.05, preferably more than 0.2, at least over the strain range
of 0 to 50%, and preferably over the strain range of 0 to 80%.
It should be noted in this regard that ~ strain is shear
strain xlO0.
By way of further explanation, the elastic (storage)
modulus G' is a measure of the energy stored and retrieved
when a strain is applied to the composition while viscous
(loss) modulus G" is a measure to the amount of energy
dissipated as heat when strain is applied~ Therefore, a value
of tan ~
O.OSc tan S ~1,
preferably
0.2 ~ tan ~ 0.8
means that the compositions will retain sufficient energy when
a stress or strain is applied, at least over the extent
expected to be encountered for products of this type, for
example, when poured from or shaken in the bottle, or stored
in the dishwasher detergent dispenser cup of an automatic
dishwashing machine, to return to its previous condition when
the stress or strain is 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
surrounding portions will follow. As a result of this
cohesiveness of the subject linear viscoelastic compositions,
the compositions will readily flow uniformly and homogeneously
from a bottle when the bottle is tilted, thereby contributing
to the physical (phase) stability of the formulation and the
low bottle residue (low product loss in the bottle) which
characterizes the invention compositions. The linear
viscoelastic property also contributes to improved physical
stability against phase separation of any undissolved
suspended particles by providing a resistance to movement of
the particles due to the strain exerted by a particle on the
surrounding fluid medium.
Also contributing to the physical stability and low
bottle residue of the invention compositions is the high
potassium to sodium ion ratios in the range of 1:1 to 45:1,
preferably 1:1 to 4:1, especially preferably from 1.05:1 to
3:1, for example 1.1:1, 1.2:1, 1.5:1, 2:1, or 2.5:1. At these
ratios the solubility of the solid salt components, such as
detergent builder salts, bleach, alkali metal silicates, and
the like, is substantially increased since the presence of the
potassium (K~) ions requires less water of hydration than the
sodium (Na+) ions, such that more water is available to
dissolve these salt compounds. Therefore, all or nearly all
of the normally solid components 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 ~uspended solids present in the formulation there
is no or only reduced tendency for undissolved particles to
settle out of the compositions causing, for example, formation
2 ~ g ~
of hard masses of particles, which could result in high bot~le
residues (i.e. 105s oE product). Furthermore, any undissolved
solids tend to be present in extremely small particle sizes,
usually colloidal or sub-colloidal, such as 1 micron or less,
thereby further reducing the tendency for the undissolved
particles to settle.
A still further attribute of the lnvention compositions
contributing to the overall product stability and low bottle
residue is the high water absorption capacity of the cross-
linked polyacrylic acid type thickening agent. As a result of
this high water absorption capacity virtual].y all of the
aqueous vehicle component is held tightly bound to the polymer
matrix. Therefore, there is no or substantially no free water
present in the invention compositions. This absence of free
water (as well as the cohesiveness of the composition) i9
manifested by the observation that when the composition i9
poured from a bottle onto a piece of water absorbent filter
paper virtually no water i9 absorbed onto the filter paper
and, furthermore, the mass of the linear viscoelastic material
poured onto the filter paper will retain its shape and
structure until i~ i9 again subjected to a stress or strain.
As a result of the absence of unbound or free water, there is
virtually no phase separation between the aqueous pha~e and
the polymeric matrix or dissolved solid particles. This
characteristic is maniEested by the fact that when the subject
compositions are subjected to centrifugation, e.g. at 1000 rpm
for 30 minutes, there is no phase separation and the
composition remains homogeneous.
~' ~ 7 ~
However, it has also been discovered that linear
viscoelasticity and K/Na ratios in the above-mentione~ range
do not, by themselves, assure long term physical stability (as
determined by phase separation). In order to ma~imize
physical (phase) stability, the den~ity of the composition
should be controlled such that the bulk density of the liquid
phase is approximately the same as the bulk density of the
entire composition, including the polymeric thickening agent.
This control and equalization of the densities is achieved,
according to the invention, by providing the composition with
a bulk density of at least 1.28 g/cc, preferably at least 1.32
g/cc, up to 1.42 g/cc, preferably up to 1.~0 g/cc.
Furthermore, to achieve these relatively high bulk densities,
it i9 important to minimize the amount of air incorporated
into the composition (a density of 1.42 g/cc is essentially
equivalent to zero air content).
It has previously been found in connection with other
types of thickened aqueous liquid, automatic dishwasher
detergent compositions that incorporation of finely divided
air bubbles in amounts up to 8 to 10~ by volume can function
effectively to stabili~e the composition against phase
separation, but that to prevent agglomeration of or escape of
the air bubbles it was important to incorporate certain
surface active ingredients, especially higher fatty acids and
the salts thereof, such as stearic acid, behenic acid,
palmitic acid, sodium stearate, aluminum stearate, and the
like. These surface active agents apparently functioned by
forming an interfacial film at the bubble surface while also
forming hydrogen bonds or contributing to the electrostatic
attraction with the suspended particles, such that the air
bubbles and attracted particles formed agglomerates of
approximately the same density as the density of the
continuous liquid phase.
Therefore, in a preferred embodiment of the present
invention, stabilization of air bubbles which may become
incorporated into the compositions during normal processing,
such as during various mixing steps, is avoided by post-adding
the surface active ingredients, including Eatty acid or fatty
acid salt stabilizer, to the remainder of the composition,
under low shear condition~ using mixing devices designed to
minimize cavitation and vortex formation.
As will be described in greater detail below the surface
active ingredients present in the composition will include the
main detergent surface active cleaning agent, and will also
preferably include anti-foaming agent and higher fatty acid or
salt thereof as a physical stabilizer.
Exemplary of the cross-linked polyacrylic acid-type
thickening agents are the products sold by B.F. Goodrich under
their Carbopol trademark, especially Carbopol 941, which is
the most ion-insensitive of this class of polymers, and
Carbopol 940 and Carbopol 934. The Carbopol resins, al90
known as "Carbomer", are hydrophilic high molecular weight,
cross-linked acrylic acid polymers having an average
equivalent weight of 76, and the general structure illustrated
by the following formula:
2~7
f H
H0-'-' ~ 0 n.
Carbopol 941 has a molecular weight of 1,250,000; Carbopol
940 a molecular weight of approximately ~,000,000 and Carbopol
934 a molecular weight of approximately 3,000,000. The
Carbopol resins are cross-linked with polyalkenyl polyether,
e.~ of a polyallyl ether of sucrose having an average of
5.8 allyl groups for each molecule of sucrose. Further
detailed information on the Carbopol resins is available from
~.F. Goodrich, see, for example, the ~.F. Goodrich catalog GC-
67, Carbopol~ Water Soluble Resins.
While most favorable results have been achieved with
Carbopol 941 polyacrylic resin, other lightly cross-linked
polyacrylic acid-type thickening agents can also be used in
the compositions of this invention. As used herein
"polyacrylic acid-type" refers to water-soluble homopolymers
of acrylic acid or methacrylic acid or water-dispersible or
water-soluble salts, esters or amides thereof, or water-
soluble copolymers of these acids of their salts, esters or
ameides with each other or with one or more other etylenically
unsaturated monomers, such as, for example, styrene, maleic
acid, maleic anhydride, 2-hydroxyethylacrylate, acrylonitrile,
vinyl acetate, ethylene, propylene, and the like.
The homopolymers or copolymers are characterized by their
high molecular weight, in the range of from 500,000 to
10,000,000, preferably 500,000 to 5,000,000, especially from
' '' , .
~37~
1,000,300 to ~,ooo,ooo, and by their water solubility,
generally at least to an extent o~ up to 5~ by weight, or
more, in water at 25C.
These thickeniny agents are used in their lightly cross-
linked form wherein the cross-llnking may be accompli~hed by
means known in the polymer arts, as by irradiation, or,
preferably, by the incorporation into the monomer mixture to
be polymeri~ed 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 as described
above), and the like. Typically, amounts of cross-linking
agent to be i.ncorporated in the final polymer ma~ range from
0.01 to 1.5 percent, preferably from 0.05 to 1.2 percent,
and especially, pre~erably from 0.1 to 0.9 percent, by
weight of cross-linking agent to weight of total polymer.
Generally, those skilled in the art will recognize that the
degree of cross-linking should be sufficient to impart some
coiling of the otherwise generally linear polymeric compound
while maintaining the cross-linked polymer at least water
dispersible and highly water-swellable in an ion.ic aqueous
medium. It is also understood that the water-swelling of the
polymer which provides the desired thickening and viscous
properties generally depends on one or two mechanisms, namely,
conversion of the acid group containing polymers to the
corresponding salts, e.g. sodium, generating negative charges
along the polymer backbone, thereby causing the coiled
11
2 ~ rll ;~
molecules to expand and thicken the aqueous solution; or by
formation of hydrogen bonds, for example, between the carboxyl
groups of the polymer and hydroxyl donor. The former
mechanism is especially important in the present invention,
S and therefore, the preferred polyacrylic acid-type thickening
agents will contain free carboxylic acid (COOH) groups along
the polymer backbone. Also, it will be understood that the
degree of cross-linking should not be so high as to render the
cross-linked polymer completely inso:Luble or non-dispersible
in water or inhiblt or prevent the uncoiling of the polymer
molecules in the presence of the ionic aqueous system.
The amount of at least one high molecular weight, cross-
linked polyacrylic acid or other high molecular weight,
hydrophilic cross-linked polyacrylic acid-type thickening
agent used to impart the desired rheological property of
linear viscoelasticity will generally be in the range of from
0.1 to 2~, preferably from 0.2 to 1.4~, by weight, based on
the weight of the composition, although the amount will depend
on the particular cross-linking a~ent, ionic strength of the
composition, hydroxyl donors and the like.
The compositions of this invention must include
sufricient amount of potassium ions and sodium ions to pro~ide
a weight ratio of K/Na of at least 1:1, preferably from 1:1 to
45:1, especially from 1:1 to 3:1, more preferably from 1.05:1
to 3:1, such as 1.5:1, or 2:1. When the K/Na ratio is less
than 1 there is insufficient solubility of the normally solid
ingredients whereas when the K/Na ratio is more than 45,
especially when it is gre~ter than 3, the product becomes too
12
2 ~
liquid and phase separation begins to occur. When the K/Na
ratio is more than ~5, especially when it is greater than 3,
the product becomes too liquid and phase separation begins to
occur. When the K/Na ratios become much larger than 45, such
as in all or mostly potassium formulation, the polymer
thickener loses its absorption capacity and begins to salt out
of the aqueous phase.
The potassium and sodium ions can be made present in the
compositions as the alkali metal cation of the detergent
builder salt(s), or alkali metal silicate or alkali metal
hydroxide components of the compositions. The alkali metal
cation may also be present in the compositions as a component
of an ionic detergent, bleach or other ionizable salt compound
additive, e.g. alkali metal carbonate. In determining the
K/Na weight ratios all of these sources should be taken into
consideration.
Speci~ic examples of detergent builder salt~ include the
polyphosphates, such as alkali metal pyrophosphate, alkali
metal tripolyphosphate, alkali metal metaphospha~e, and the
like, for example, sodium or potassium tripolyphosphate
(hydrated or anhydrous), tetrasodium or ~etrapotassium
pyrophosphate, sodium or potas~ium hexa-metaphosphate,
trisodium or tripotassium orthophosphate and the like, sodium
or potassium carbonate, sodium or potassium citrate, sodium or
potassium nitrilotriacetate, and the like. The phosphate
builders, where not precluded due to local regulations, are
preferred and mixtures of tetrapotassium pyrophosphate (TKPP)
and sodium tripolyphosphate (NaTPP) (especially the
2 ~ L
hexahydrate) are especially preferred. Typical ratio~ of
NaTPP to TKPP are fro~ 2:1 to 1:8, especially from 1:1.1 to
1:6. The total amount of detergent builder salts is
preferably from 5 to 35~ by weight, more preferably from 15
to 35~, especially ~rom 18 to 30~ by weight of the
composition.
In connection with the builder salts are optionally used
a low molecular weight noncrosslinked polyacrylates having a
molecular weight of 1,000 to 100,000, more preferably 2,000 to
80,000. A preferred low molecular weight polyacrylate is
Norasol ~MW45ND manufactured by Norsoshaas and having a
molecular weight of 4,500. These low molecular weight
polyacrylates are employed at a concentration of 0.1 to 15
wt.%, more preferably 0.25 to 10 wt.~.
Other useful low molecular weight noncrosslinked polymers
are Acusol~640D provided by Rohm & Haas; Norasol QR1014 from
Norsohaas having a GPC molecular weight of 10,000.
The linear viscoelastic compositions of this 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 composition has not been fully elucidated it is
hypothesi2ed that it may function as a hydrogen bonding agent
or cross-linking agent for the polymeric thickener.
The preferred long chain fatty acids are the higher
aliphatic fatty acids having from 8 to 22 carbon atoms, more
preferably from 10 to 20 carbon atoms, and especially
14
preEerably from 12 to 1~ carbon atoms, and especially
preferably from 12 ~o 18 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 straight or
branched. Straight chain saturated fatty acids are preferred.
Mixtures of fatty acids may be used, such as those derived
from natural sources, such as tallow fatty acid, coco fatty
acid, soya Eatty acid, mixtures of these acids, etc. Stearic
acid and mixed fatty acids, e.g. stearic acid/palmitic acid,
are preferred.
The more preferred long chain fatty acids are the higher
aliphatic fatty acids having from 10 to 50 carbon atoms, more
preferably from 12 to ~0 carbon atoms, and especially
preferably from 14 to 40 carbon atoms, and most preferably
20 to 40, inclusive o~ the carbon atom of the carboxyl group
of the fatty acid. The aliphatic radical may be saturated or
unsaturated and may be straight or branched. Straight chain
saturated fatty acids are preferred. Mixtures of fatty acids
may be used, such as those deri~ed from natural sources, such
as tallow fatty acid, coco fatty acid, soya fatty acid, etc.,
or from synthetic sources available from industrial
manufacturing processes.
Thus, examples of the fatty acids include, for example,
decanoic acid, dodecanoic acid, palmitic acid, myristic acid,
stearic acid, behenic acid, oleic acid, eicosanoic acid,
tallow fatty acid, coco fatty acid, soya fatty acid, mixtures
of these acids, etc. Stearic acid and mixed fatty acids, e.g.
stearic acid/palmitic acid, are preferred.
~7~
It has, however, al50 recently been discovered by some of
us and others that further improvements in phase stabilit~,
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 C~8
to C~0. Either individual or mixtures of these longer chain
length fatty acids can be used, however, the average chain
length should be in the range of from 20 to 32 carbon atoms,
especially 2g to 30 carbon atoms and mixture of fatty acids
encompassing this range are preferred. Suitable mixed fatty
acids are commercially 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 directly 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, IIB and IIIB, such as magnesium,
calcium, aluminum and zinc, although other polyvalent metals,
including those of Groups IIIA, IVA, VA, IB, IVB, VB VIB, 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 metals may be present in the divalent to
16
2 ~
pentavalent state. Preferably the metal salts are u~ed in
their higher oxidation states. Naturally, Eor use in
automatic dishwashers, as well as any other application~ where
the invention composition will or may come in contact with
articles u~ed for the handling, storage or serving 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 alkali metal and calcium and
magnesium salts are especially higher preferred as 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 the nature of the
fatty acid or its salt, the nature and amount of the
thickening agent, detergent active compound, inorganic salts,
other ingredients, as well as the anticipated storage and
shipping conditions.
Generally, however, amounts of the fatty acid or fatty
2Q acid salt stabilizing agents in the range of from 0.02 to 2%,
preferably 0.04 to 1%, more preferably from 0.0~ to 0.8~,
especially preferably from 0.08 to 0.4~, provide a long term
stability and absence of phase separation upon standing or
during transport at both low and elevated temperatures as are
required for a commercially acceptable product.
Depending on the amounts, proportions and types of fatty
acid physical stabilizers and polyacrylic acid-type thickening
agents, the addition of ~he fatty acid or salt not only
17
increases physical stability but also provides a simultaneous
increase in apparent viscosity. Amounts of fatty acid or salt
to polymeric thickening agent in the range of from 0.08-0.4
weight percent fatty acid salt and from 0.~-1.5 weight
percent polymeric thlckening ayent are usually sufficient to
provide these simultaneous benefits and, therefore, the use of
these ingredients in these amounts is most preferred.
In order to achieve the desirecl benefit ~rom the fatty
acid or fatty acid salt ~tabilizer, without stabilization of
excess incorporated air bubbles and consequent excessive
loweriny of the product bulk density, the fatty acid or salt
should be post-added to the formulation, pre~erably together
with the other surface active ingredients, including detergent
active compound and anti-foaming agent, when present. These
surface active ingredients are preferably added as an emulsion
in water wherein the emulsified oily or fatty materials are
finely and homogeneously dispersed throughout the aqueous
phase. To achieve the desired fine emul~ification of the
fatty acid or fatty acid salt and other surface active
ingredients, it is usually necessary to heat the emulsion (or
preheat the water) to an elevated temperature near the melting
temperature of the fatty acid or its salt. For e~ample, for
stearic acid having a melting point of 68C-69C, a temperature
in the range of between 50C and 70C will be used. For lauric
acid (m.p.=47C) an elevated temperature o 35C to 50C can be
used. Apparently, at these elevated temperatures the fatty
acid or salt and other surface active ingredients can be more
18
2 ~
readily ancl uniformly dispersed (emulsified) in the ~orm o~
fine droplets throughout the composition.
In contrast, as will be shown in the examples which
follow, if the fatty acid is .simply post-added at ambient
temperature, the composition is not linear viscoelastic as
defined above and the stability of the composition is clearly
inferior.
Foam inhibition is important to increase dishwasher
machine efficiency and minimize destabilizing effects which
might occur due to the presence of e~cess foam within the
washer during use. Foam may be reduce by suitable selection
of the type and/or amount of detergent active material, the
main foam-producing component. The degree of foam is also
somewhat dependent on the hardness of the wash water in the
machine whereby ~uitable adjustment of the proportions of the
builder salts such as NaTPP which has a water softening
effect, may aid in providing a degree of foam inhibition.
However, it i3 generally preferred to include a chlorine
bleach stable foam depressant or inhibitor. Particularly
effective are the alkyl phosphoric acid estexs of the formula
HO-~-R
OR
and especially the alkyl acid phosphate esters of the formula
ll
HO-P-OR
OR
19
2 ~
In the above fo~nulas, one or both R groups in each type of
ester may represent independently a Cl2-C20 a]kyl group. The
ethoxylated derivatives of each type of ester, for example,
the condensation products of one mole of ester with from 1 to
10 moles, preferably 2 to ~ moles, more preferably 3 or 4
moles, ethylene oxide can also be used. Some examples of the
foregoing are commercially available, such as the product~ SAP
from Hooker and LPKN-158 from Knapsack. Mixtures of the two
types, or any o~her chlorine bleach stable types, or mixtures
of mono- and di-esters of the same t~pe, may be employed.
Especially preferred is a mixture of mono- and di-CI6-C~8 alkyl
acid phosphate esters such as monostearyl/distearyl acid
phosphates 1.2/1, and the 3 to 4 mole ethylene oxide
condensates thereof. When employed, proportions of 0.0 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 depressant (e)
generally ranging from 10:1 to 1:1 and preferably 5:1 to
1:1. Other defoamers which may be used include, for example,
the known silicones, such as available from Dow Chemicals. In
addition, it is an advantageous feature of this invention that
many of the stabilizing salts, such as the stearate salts, for
example, aluminum stearate, 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-
isocyanurate, dichloro-dimethyl hydantoin, or chlorinated TSP,
alkali metal or alkaline earth metal, e.g. potassium, lithium,
~ ~.Q~3~
magnesium and especially sodium, hypochlorite i.s preferred.
The composition should contain sufficient amount of chlorine
bleach compound to provide 0.2 to ~.0% by weight oE available
chlorine, as determined, for example by aciclification of 100
parts of the composition with excess hydrochloric acid. A
solution containing 0.2 to 4.0~ by weight of sodium
hypochlorite contains or provides roughly the same percentage
of available chlorine. 0.~ to 1.6~ by weight of available
chlorine i9 especially preferred. For example, sodium
hypochlorite (NaOCL) solution of Erom 11 to 13% available
chlorine in amounts of 3 to 20~, preferably 7 to 12~, can be
advantageously used.
Detergent active material useful herein should be stable
in the presence of chlorine bleach, especially hypochlorite
bleach, and for this purpose those of the organic anionic,
amine oxide, phosphine oxide, sulphoxide or betaine water
dispersible surfactant types are preferred, the first
mentioned anionics being most preferred. Particularly
preferred surfactants herein are the linear or branched alkali
metal mono- and/or di-(C8-CI~) alkyl diphenyl oxide mono- and/or
di-sulphates, commercially a~ailable for example as DOWFAX
(registered trademark) 3B-2 and DOWFAX 2A-l. ln addition, the
surfactant should be compatible with the other ingredients of
the composition. Other suitable organic anionic, non soap
surfactants include the primary alkylsulphates,
alkylsulphonates, alkylarylsulphonates and sec.-
alkylsulphates. Examples include sodium Cl0-C~8 alkylsulphates
such as sodium dodecylsulphate ancd sodium tallow
~"~ J~
alcoholsulphate; sodium C~0- C18 alkanesulphonates such as sodium
hexadecyl-1-sulphonate and sodium Cl2-C~8
alkylbenzenesulphonates such as sodium
dodecylbenzenesylphonates. The corresponding potassium salts
may also be employed.
As other suitable surfactants or detergents, the amine
oxide surfactants are typically of the structure R2RINO, in
which each R represents a lower alkyl group, for instance,
methyl, and Rl represents a long chain alkyl group having Erom
8 to 22 carbon atoms, for instance a lauryl, myristyl,
palmityl or cetyl group. Instead of an amine oxide, a
corresponding surfactant phosphine oxide R2RIPO or sulphoxide
RR~SO can be employed. Betaine surfactants are typically of
the structure R2RIN+R'7COO-, in which each R represents a lower
alkylene group having from 1 to 5 carbon atoms. Specific
examples of these surfactants include lauryl-dimethylamine
oxide, myristyl-dimethylamine oxide, myristyl-dimethylamine
oxide, the corresponding phosphine oxides and sulphoxides, and
the corresponding betaines, including dodecyldimethylammonium
acetate, tetradecyldiethylammonium pentanoate,
hexadecyldimethylammonium hexanoate and the like. For
biodegradability, the alkyl groups in-~hese surfactants should
be linear, and such compounds are preferred.
Surfactants of the foregoing type, all well known in the
art, are described, for example, in U.S. Pa~ents 3,985l668 and
4,271,030. If chlorine bleach i9 not used than any of the
well known low-foaming nonionic surfactants such as
alkoxylated fatty alcohols, e.g. mixed ethylene oxide-
propylene oxide condensates of C8-C22 fatty alcohols can also be
used.
The chlorine bleach stable, water dispersible organic
detergent-active material (surfactant) will normally be
present in the composition in minor amounts, generally 1% by
weight oE the composition in minor amounts, generally 1% by
weight of the composition, although smaller or larger amounts,
such as up to 5%, such as from 0 to 5~, preferably form 0.1
or 0.~4 to 3~ 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, is generally employed in an
amount ranging from 5 to 20 weight percent, preferably 5 to
15 weight percent, more preferably 8 to 12~ in the
composition. The sodium or potassium silicate is generally
added in the form of an aqueous solution, preferably havin~
Na20:SiO2 or K20: SiO2 ratio of 1:1.3 to 1:2.8, especially
preferably 1:2.0 to 1:2.6. At this point, i~ should be
mentioned that many of the other components of this
composition, especially alkali metal hydroxide and bleach, are
also often added in the form of a preliminary prepared a~ueous
dispersion or solution.
In addition to the detergent active surfactant, foam
inhibitor, alkali metal silicate corrosion inhibitor, and
detergent builder salts, which all contribute to the cleaning
performance, it i9 also known that the effectiveness of the
liquid automatic dishwasher detergent compositions is related
to the alkalinity, and particularly to moderate to high
,
'
.
alkalinity levels. Accordingly, the compositions of this
invention will have pH values of at least 9.5, preferably at
least 11 to as high as 14, generally up to 13 or more, and,
when added to the aqueous wash bath at a typical concentration
level of 10 grams per liter, will provide a pH in the wash
bath of at least 9, preferably at least 10, such as 10.5,
11, 11.5 or 12 or more.
The alkalinity will be achieved, in part by the alkali
metal ions contributed by the alkali metal detergent builder
salts, e.g. sodium tripolyphosphate, tetrapotassium
pyrophosphate, and alkali metal silicate, however, it is
usually necessary to inclu~e alkali metal hydroxide, e.g. NaOH
or KOH, to achieve the desired high alkalinity. Amounts of
alkali metal hydroxide in the range of (on an active basis) of
from 0.5 to 8%, preferably from 1 to 6~, more preferably from
1.2 to 4~, by weight of the composition will be sufficient to
achieve the desired pH level and/or to adjust the K/Na weight
ratio.
Other alkali metal salts, such as alkali metal carbonate
may also be present in the compositions in minor amounts, for
example from 0 to 4%, preferably 0 to 2~, by weight of the
composition.
Other conventional ingredients may be included in these
compositions in small amounts, generally less than 3 weight
percent, such as perfume, hydrotropic agents such as the
sodium benzene, toluene, xylene and cumene sulphonates,
preservatives, dyestuffs and pigments and the like, all of
course being stable to chlorine bleach compound and high
24
2 ~ J~
alkalinity. Especially preferred ~or coloring are the
chlorinated phythalocyanines and polysuphides of
aluminosilicate which provide, respectively, pleasing green
and blue tints. TiO2 may be employed for whitening or
neutralizing off-shades. Even more preferred colorants used
at a concentration of 0.01 to 1.0 wt. ~ are CI Direct Yellow
# 2~ and Grapthlol Green pigment both made by Sandoz Chemical
Corp.
Although for the reasons previously discussed excessive
air bubbles are not often desirable in the invention
compositions, depending on the amounts of dissolved solids and
liquid phase densities, incorporation of small arnounts of
finely divided air bubbles, generally up to 10% by volume,
preferably up to 4% by volume, more preferably up to 2~ by
volume, can be incorporated to adjust the bulk density to
approximate liquid phase density. The incorporated air
bubbles should be finely divided, such as up to 100 microns
in diameter, preferably from 20 to 40 microns in diameter,
to assure maximum stability. ~lthough air is the preferred
gaseous medium for adjusting densities to improve physical
stability of the composition other inert gases can also be
used, such as nitrogen, carbon dioxide, helium, oxygen, etc.
The amount of wa~er contained in these compositions
should, of course, be neither 50 high as to produce unduly low
viscosity and fluidity, nor so low as to produce unduly high
viscosity and low flowability, linear viscoelastic properties
in either case being dimini~hed or destroyed by increasing tan
Such amount is readily determined by routine
2 ~ /7 ~
experimentation in any particular instance, generally ranginy
from 30 to 75 weight percent, prefera~ly 35 to 65 weight
percent. The water should also be preferably deionized or
softened.
The manner of formulating the invention compositions is
also important. ~s discussed above, the order of mixing the
ingredients as well as the manner in which the mixing is
performed will generally have a significant effect on the
properties of tha compo~ition, and in particular on product
density (by incorporation and stabilization of more or less
air) and physical stability (e.g. phase separation). Thus,
according to the preferred practice of this invention the
compositions are prepared by first forming a dispersion of the
polyacrylic acid-~ype thickener in water under moderate to
high shear conditions, neutralizing the dissolved polymer to
cause gelation, and then introducing, while continuing mixir,g,
the detergent builder salts, alkali metal dilicates, chlorine
bleach compound and remaining detergent additi~es, including
any previously unused alkali metal hydroxide, if any, other
than the surface-active compounds. All of the additional
ingredients can be added simul~aneously or se~uentially.
Preferably, the ingredients are added sequentially, although
it is not necessary to complete the addition of one ingredient
before beginning to add the next ingredient. Furthermore, one
or more of these ingredients can be divided into portions and
added a~ different times. These mixing steps should also be
performed under moderate to high shear rates to achieve
complete and uniform mixing. These mixing steps may be
2 ~
carried out at room temperature, although the polymer
thickener neutralization (gelation) is usually exothermic.
The composition may be allowed to age, if necessary, to cause
dissolved or dispersed air to dissipate 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 previously
formed mixture in the form of an aqueous emulsion (using from
1 to 10~, preferably from 2 to 4~ of the total water added to
the composition other than water added as carrier for other
ingredients or water of hydration) which is pre-heated to a
temperature in the range of from Tm~5 to Tm-20, preferably
from Tm to TM-10, where 1~ is the melting point temperature
of the fatty acid or fatty acid salt. For the preferred
stearic acid stabilizer the heating temperature is in the
range of 50C to 70C. However, if care is taken to avoid
excessive air bubble incorporation during the gelatin step or
duriny the mixing of the detergent builder salts and other
additives, for example, by operating under vacuum, or using
low shearing conditions, or special mixing operatatus, 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 invention includes, on a weight
basis:
27
2 ~
(a) 10 to 35~, preferably 15 to 30~, ~lkali metal
polyphosphate detergent builder;
(b) 5 to 15~, preferably 8 to 12~, alkali metal
silicate;
(c) 1 to 6~, preferably 1.2 to 4%, alkali metal
hydroxide;
(d) 0 to 5~, preferably 0.1 to 3%, chlorine bleach
stable, water-dispersible, low-foaming organic detergent
active material, preferably non-soap anionic detergent;
(e) 0 to 1.5~, preferably 0.1 to 0.5~, chlorine bleach
stable foam depressant;
(f) chlorine bleach compound in an amount to provide
0.2 to 4%, preEerably 0.8 to 1.6~, of available chlorine;
(g) at least one polymeric thickening agent such as a
high molecular weight hydrophilic cross-linked polyacrylic
acid thickening agent in an amount to pro~ide a linear
viscoelasticity to the formulation, preferably from 0.1 to
2.0~, more preferably from 0.2 to 1.0%;
(h) a long chain fatty acid or a metal salt of a long
chain fatty acid in an amount effective to increase the
physical stability of the compositions, preferably from 0.02
to 2.0%, more preferably from 0.04 to 1.0%; and
(i) balance water, preferably from 30 to 75~, more
preferably from 35 to 65~; and wherein in (a) the alkali
metal polyphosphate includes a mixture of from 5 to 30%,
preferably from 12 to 22% of tetrapotassium pyrophosphate,
and from 0 to 20~, preferably from 3 to 18~ of sodium
tripolyphosphate, and wherein ln the entire composition the
28
2 ~
ratio, by weight, of potassium ions to sodium ions is from
1.05/1 to 3/1, preferabl~ from ~ to 2.5/l, the
compositions having an amount of air incorporated therein such
that the bulk density of the composition i9 from 1.28 to 1.42
g/cc, preferably from 1.32 to 1.40 g/cc. The improved gel-
like viscoelastic automatic dishwashing composition are
further describe~ as containing 10 to 60 weight percent of
an alkali metal containing compound which is selected from the
group consisting essentially of alkali metal hydroxides,
alkali metal tripolyphosphates, alkali metal pyrophosphates,
alkali metal carbonates and alkali metal silicates, wherein
there is present in the composition both potassium ions and
~odium ions in a ratio o~ 1/1 to 45/1, 0 to 1.5 weight
percent of a foam depressant, 0 to 5 weiyht percent oE a
chlorine bleach stable, water-dispersible organic detergent
active material, 0.02 to 2.0 weight percent of a long chain
fatty acid or a metal salt thereof and a means for
substantially preventing the composition from wetting and
adhering to an interior vertical surface of a polyolefinic
bottle; wherein the means comprises adding a polymeric
thickening agent such as a high molecular weight polyacrylic
thickening agent to the composition, wherein substantially all
of the normally solid components of the composition are
present dissolved in the aqueous phase, and substantially all
of the water is tightly bound to the polymeric thickening
agent and the composition has a bulk density of from 1.28 g/cm3
to 1.42 g/cm3 and the composition does not exhibit phase
separation and remains homogenous, when the composition is
29
s~
centrlfu~3ed at 1000 rpm for three mi~utes. The composition
can further include 0.1 to 10.0 weight percent of a
polyacrylate havlng a molecular weight of 1,000 to 100,000
and a chlorine containing compound to provide 0.2 to 4.0
weight percent of available chlorine.
Another especially preferred embodiment, the thickened
linear viscoelastic aqueous automatic dishwasher detergent
composition of this invention in~ludes, on a weight basis:
(a) (i) 8 ~o 25~, preferably 10 to 20%, potassium
tripolyphosphate detergent builder;
(ii) 2 to 10%, preferably 4 to 8%, sodium
tripolyphosphate detergent builder, at an (i)/(ii) weight
ratio of from 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
hydroxide;
(d) 0.1 to 3%, preferably 0.5 to 2~, chlorine bleach
stable, water-dispersible, low-foaming organic detergent
active material, preferably non-soap anionic detergent;
(e) 0 to 1.5~, preferably 0.1 to 0.5%, chlorine bleach
stable foam depressant;
~f) chlorine bleach compound in an amount to provide
0.2 to 4~, preferably 0.8 to 1.6%, of available chlorine;
(g) at least one non-linear, water-dispersible
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
~ ~3 ~ ~ ~ Q 1
viscoelasticity to the formulation, preEerably from 0.2 to
2~, especially preferably from 0.~ to 1.5%, more preferably
from 0.4 to 1.0~;
(h) a long chain fatty acid or a metal salt of a long
chain fatty acid in an amount effective to increase the
physical stability of the compositions, preferably from 0.02
to 0.4%, more pre~erably from 0.1 to 0.3%;
(i) 0 to 10~, preferably 1 to a%, especially 2 to 6% of
non-cross-linked polyacrylic acid having a molecular weight in
the range of from 800 to 200,000, p:referably 1000 to 150,000,
especially 2,000 to 100,000; arld
(j) balance water, preferably from 30 to 75%, more
preferably from 35 to 65%; and wherein in the entire
composition the ratio, by weight, of potassium ions to sodium
ions is from 1.05/1 to 3/1 or 4/1, preferably from 1.1/1 to
2.5/1. The compositions may also have an amount of air
incorporated therein such that the bulk density of the
composition is from 1.28 to 1.42 g/cc, preferably from 1.32
to 1.42 g/cc, more preferably from 1.35 to 1.40 g/cc.
Another especially preferred embodiment, the
thickened linear viscoelastic aqueous automatic dishwasher
detergent composition of this invention includes, on a weight
basis:
(a) 10 to 35%, preferably 15 to 30%, of at least one
alkali metal detergent builder salt;
(b) 0 to 15, preferably 8 to 12%, alkali metal silicate;
(c) 1 to 6%, preferably 1.2 to ~, alkali metal
hydroxide;
2 ~ ~ ~U
(d) 0 to 3~, preferably 0.1 to 2%, chlorine bleach
stable, water-dispersible, low-foaming organic detergent
active material, pre:Eerably non-soap anionic detergent;
(e) 0 to 1.5~, preferably 0.1 to 0.5~, chlorine bleach
stable foam depressant;
(f) chlorine bleach compound in an amount to provide
0.2 to 4~, preferably 0. a to 1.6%, of available chlorine;
(g) high molecular weight hydrophilic cross-linked
polyacrylic acid thickening agent in an amount to provide a
linear viscoelasticity to the formulation, preferably from
0.1 to 2.0~, more preferably from 0.4 to 1.5~;
(h) a long chain fatty acid or a metal salt of a long
chain fatty acid in an amount effective to increase the
physical stability of the compositions, preferâbly from 0.08
to 2.0%, more preferably from 0.04 to 0.5~; and
(i) balance water, preferably from 30 to 75%, more
preferably from 35 ~o 65~; and wherein in (a) the alkali
metal polyphosphate includes a mixture of from 5 to 30~,
preferably from 12 to 22~ of tetrapotassium pyrophosphate,
and from 0 to 20~, preferably from 3 to 18~ of sodium
tripolyphosphate, and wherein in the entire composition the
ratio, by weight, of potassium ions to sodium ions is from
1.05/1 to 3/1, preferably from 1.1/1 to 2.5/1, the
compositions ha~ing an amount of air incorporated therein such
that the bulk density of the composition is from 1.32 to 1.42
g/cc, preferably from 1.35 to 1.40 g/cc.
(j) 0.01 to 1.09~ of a chlorine stable dye or chlorine stable
pigment.
32
The compositions will be supplied to the consumer in
suitable dispenser containers preferably formed of molded
plastic, e~pecially polyolefin plastic, and most preferably
polyethylene, for which the invention compositions have
particularly favorable 51ip characteristics. The slip
characteristic of the composition i~: manifested by the fact
that the in~tant compositions do not substantially adhere to
the interior vertical surface of a polyolefinic bottle such as
a blow molded high density polyethylene bottle or a
polyethylene tetraphthatate bottle. This slip characteristic
of the composition i9 directly attributable to the addition of
the polymeric thickening agent to the composition which causes
the composition to obtain its gel-like viscoelastic
characteristic. In addition to their linear viscoelastic
character, the compositions of this invention may also be
characterized as pseudoplastic gels (non-thixotropic) which
are typically near the borderline between liquid and solid
viscoelastic gel, depending, for example, on the amount and
type of the polymeric thickener. The invention compositions
can be readily poured from their containers without any
shaking or Rqueezing, although squeezable containers are often
convenient and accepted by the consumer for gel-like products.
The liquid aqueous linear viscoelastic automatic
dishwasher compositions of this invention are readily employed
in known manner for washing dishes, other kitchen utensils and
the like in an automatic dishwasher, provided with a suitable
detergent dispenser, in an aqueous wash bath containing an
effective amount of the composition, generally sufficient to
2 ~
fill or partlally fi].l the automatic dispenser cup of the
particular machine being used.
The invention also provides a method for cleaning
dishware in an automatic dishwashing machine with an aqueous
wash bath containing an effective amount of the liquid linear
viscoelastic automatic dishwasher detergent composition as
described above. The composition can be readily poured from
the polyethylene container with little or no squeezing or
shaking into the dispensing cup of ~he automatic dishwashing
machine and will be sufficiently viscous and cohesive to
remain securely within the dispensing cup until shear forces
are again applied thereto, such as by the water spray Erom the
dishwashing machine.
The invention may be put into practice in various ways
and a number of specific embodiments will be described to
illustrate the invention with reference to the accompanying
examples.
All the amounts and proportions referred to herein are by
weight of the composition unless otherwise indicated.
Example 1
The following formulation~ A-K were prepared as described
below:
34
_:~ ~ _~ __lli _ ~ ~ ~ _ I_ ~ ~ ~
K m O N , ~ 0 N ,l N ~1 O ~ V , ~
_ _ _ _ _ _ ___ _ _ _ _
~ m ~ ~ ll N ~ N l ~ ~ O ~ N ~ ~
~! __ _ _ _ _ , __ _ u~ o __
H m _ N . ~ N _ __ _ _ . A _ _
m O 'l N 0 'l 'l r ~ ~ O ~ N ' ~r
_ _ __ _ _ _ _ _ _ _
~ m Nr~ ' N , N ,l N H O ~ N , ~r
_ _ . _ _ _ _ ~ _
~ m ~ ~ ll N ~ ~ ll ~ ~ ~ ~ A ~ ~
~! ; Ln - o 111 r~ __ _ _ ~ o _ o~ Ll~
~ ~ ,1 r~l l ~ t~ ~ l l ~1 l a~ Y l ,~
_ _ _ _ .. _ _ _ _ _ _
_ m O N ~ N ~ N ~ ~ ~ O ~ N ~ 0
_ _ _ _ _ _ _ _ _ _--O _ _
r~ ~ o ~ ll 'n ~ ~ ', ~ ~ ~1 ~ Y l
O N _ In ~ N , N H O m V O N
. _ _ _ __ _ _ __ _ _
~ m C Nr. ' m ~1 ' N ~1 O m v ' N
~ ~ _ ~i ~ __ e~_ ~ ~1115 11~1 ~_ ~11 ~11 _
~ ~ ~r ~ _ N~ ~ o\
H ~ ~Z O In In ~ H 111 H ~ô In m H V o\~ H
H ~ H ~J m K K ~i ~ H ~ ~ 3 _ m rJ ~ ~ _
~7~ f3~
~i ~ 9
t` 0
K . ~
~ ~ Ln .
~ .~ o o ~ O ~
~_~i_ O O R ~.
H lA A O ,q
~ _ _ O _ ~r~
. . . ~ U r~
P l,l i 4 N A X
. t~ ~r ~0 u
.~ O' O 0~
I_ _ O O V h
l O O ~
'~ _ _ A h O ~ (I)
O O
~ A A
~ _ ._
-" o o ~1 U :~ O h
o o ~ ~ U
~ L~ ~ ._._ . __
o ,~ .~ o o ,u~ ~
_~ _ . _ a) a~ o o
r~ O o u~
. . . ~ ~ ~
m~ O O 4~ ~ ~, h a
_ . _
~ H h a h w
~ ,i ~ o o ,X l~
:b..,. _ ~ __ _ o 3 h h
U . ~ K O ,1 a) aJ h ~a
H O H ~i H o b~ O
~ ~3 ~ cn O ~ u~ o ~
E~ ~ O E~ P~ o 0\O
cn~o~0 cq~_ . . .
~1 . _ ~a __ ~
2~3S,~
Formulations A, B, C, D, E, G, J, and K are prepared by
first forming a uniform dispersion of the Carbopol 9~1 or 940
thickener in 97~ of the water (balance). The Carbopol is
slowly added to deionized water at room temperature using a
mixer equipped with a premier blade, with ayitation set at a
medium shear rate, as recommended by the manufacturer. The
dispersion is then neutralized by addition, under mixing, of
the caustic soda (50~ NaO~ or KOH) component to form a
thickened product of gel-like consistency.
To the resulting gelled dispersion the silicate,
tetrapotassium pyrophosphate (TKPP), sodium tripolyphosphate
TP(TPP, Na) and bleach, are added sequentially, in the order
stated, with the mixing continued at medium shear.
Separately, an emulsion of the phosphate anti-foaming
agent (LPKN), ~tearic acid/palmitic acid mixture and detergent
~Dowfax 3B2) is prepared by adding these ingredients to the
remaining 3~ of water (balance) and heating the resulting
mixture to a temperature in the range of 50C to 70C.
This heated emulsion i9 then added to the previously
prepared gelled dispersion under low shear conditions, such
that a vortex is not formed.
The remaining formulations F, H and ~ are prepared in
essentially the same manner as described above except that the
heated emulsion of LPKN, stearic acid and Dowfax 3B2 is
directly added to the neutralized Carbopol dispersion prior to
the addition of the remaining ingredients. As a result,
formulations F, H and I, have higher levels of incorporated
air and densities below 1.30 g/cc.
37
2 ~3 1~
The rheograms for the formulations A, C, D, G and ~ are
shown in figures 1-5, respectively, and rheograms for
formulations H, I and K are shown in figures 6, 7 and 8
respectively.
These rheograms are obtained with the System 4 Rheometer
Erom ~heometrics equipped with a Fluid Servo with a 100 grams-
centimeter torque transducer and a 50 millimeter parallel
plate geometry having an 0.8 millimeter gap between plates.
All measurements are made at room temperature (25C*1C) in a
humidity chamber after a 5 minute or 10 minute holding period
of the sample in the gap. The measurements are made by
applying a frequency of 10 radians per second.
All of the co~position formulations A, B, C, D, G and J
according to the preferred embodiment of the invention which
include Carbopol 941 and stearic acid exhibit linear
viscoela~ticity as seen from the rheograms of figure 1-5.
Formulation E which includes Carbopol 941 but not stearic acid
showed no phase separation at either room temperature or 100F
after 3 week~, but exhibited 10% phase separation after 8
weeks at room temperature and after only 6 weeks at 100F.
Formulation K, containing Carbopol 940 in place of
Carbopol 941, as seen from the rheogram in figure 8, exhibits
substantial linearity over the strain range of from 2~ to 50~
(G' at 1~ strain-G' at 50~ strain 500 dynes/~q.cm.) although
tan ~ at a strain above 50~.
38
2 ~
Example 2
This example demonstrates the importance of the order of
addition of the surface active component premix to the
remainder of the composition on product density and stability.
The following formulations are prepared by methods A and
B :
Ingr dlent
Water, deionized Balance
Carbopol 941 0.5
NaOH (50~) 2.4
Na Silicate (47.5~) 21
TKPP 15
TPP, Na 13
Bleach (1%) 7.5
LPKN 0.16
Stearic Acid 0.1
Dowfax 3B2
Method A:
The Carbopol 941 i9 dispersed, under medium shear rate,
using a premier blade mixer, in deionized water at ambient
temperature. The NaOH is added, under mixing, to neutralize
and gel the Carbopol 941 dispersion. To the thickened mixture
the following ingredients are added sequentially while the
stirring i9 continued: sodium silicate, TKPP, TPP, and
bleach.
Separately, an emulsion i~ prepared by adding the Dowfax
3B2, stearic acid and LPKN to water while mixing at moderate
shear and heating the mixture to o5C to finely disperse the
emulsified surface active ingredients in the water phase.
This emulsion premix is then slowly added to the Carbopol
dispersion while mixing under low shear conditions without
forming a vortex. The results are shown below.
39
2 ~ ,r~ ~
Method B:
Method A i9 repeated except that the heated emulsion
premix is added to the neutralized Carbopol 941 dispersion
before the sodium stearate, TKPP, TPP, and bleach. The
results are also shown below.
Method AMethod B
Density (g/cc) 1.38 1.30
Stability (RT-8 weeks) 0.00~ 7.00~
Rheogram Fig. 9Fig.10
From the rheograms of figures 9 and 10 it is seen that
both products are linear viscoelastic although the ela.stic and
viscous moduli G' and G~' are higher for Method A than for
Method ~.
From the results it i9 seen that early addition of the
surface active ingredients to the Carbopol gel significantly
increases the degree of aeration and lowers the bulk density
of the final product. Since the bulk density i9 lower than
the density of the continuous liquid phase, the liquid phase
undergoes i.nverse separation (a clear liquid phase forms on
the bottom of the composition). This process of inverse
separation appears to be kinetically controlled and will occur
faster as the density of the product becomes lower.
Example 3
This example shows the importance of the temperature at
which the premixed surfactant emulsion is prepared.
Two formulations, L and M, having the same composition as
in Example 2 except that the amount of stearic acid was
increased from 0.1~ to 0.~ are prepared as shown in Method A
~7~
for formulation L and by the following Method C Eor
formulation M.
Method C
The procedure of Method A is repeated in all details
except that elnulsion premix of the surEace active ingredients
is prepared at room temperature and is not heated before being
post-added to the thickened Carbopol dispersion containing
silicate, builders and bleach. The rheograms for formulations
L and M are shown in figures 11 and 12, respectively. From
these rheograms it is seen that formulation L i9 linear
viscoelastic in both G' and G" whereas formulation M is non-
linear viscoelastic particularly for elastic modulus G' (G' at
1% strain-G~ at 30% strain > 500 dynes/cm2) and also for G" (G"
at 1% strain-G" at 30~ strain ~ 300 dynes/cm2).
Formulation L remains stable after storage at RT and 100F
for at least 6 weeks whereas formulation M undergoes phase
separation.
Comparative Example 1
The following formulation is prepared without any
potassium salts:
Weiqht %
Water Balance
Carbopol 941 0.2
NaOH (50~) 2.4
TPP, Na (50%) 21.0
Na Silicate (47.5%) 17.24
Bleach ~1%) 7.13
Stearic Acid 0.1
LPKN (5%) 3.2
Dowfax 3B2 0.8
Soda Ash 5.0
Acrysol LMW 45-N 2.0
41
.7 ~ ~
The procedure used is analogous to Method A of Example 2
with the soda ash and Acrysol ~MW 45-N (low molecular weight
polyacrylate polymer) being added before and after,
respectively, the silicate, TPP and bleach, to the thickened
Carbopol 941 dispersion, followed by addition to the heated
surface active emulsion premix. The rheogram is shown in
figure 13 and is non-linear with G~/G~ (tan~) ~ 1 over the
range of strain of from 5~ to 80~.
Example 4
Formulations A, B, C, D and K according to this invention
and comparative formulations F and a commercial liquid
automatic dishwasher detergent product as shown in Table 1
above were subjected to a bottle residue test using a standard
polyethylene 28 ounce bottle as used for current commercial
liquid dishwasher detergent bottle.
Six bottles are filled with the respective samples and
the product is dispensed, with a minimum of force, in 80 gram
dosages, with a 2 minute rest period between dosages, until
flow stops. At this point, the bottle was vigorously shaken
to try to expel additional product.
The amount of product remaining in the bottle is measured
as a percentage of the total product originally filled in the
bottle. The results are shown below.
42
2~7~
Bottle R sidue
Formulation Res~idue
A 8
B 10
C 6
: D 5
K 7
F* 4
Commercial Product 20
*The sample separates upon aging
Example 5 - The following formulations A-F were prepared as
described below:
2a7~
r_c -, _ m o _ ul, ~:, _ _ ._ ~, _ 'o`7 =
~ O _ _ O _ 0 _ N _ O C O ~1 O O _
¦ IYi 01 l l O ~ O l r~ ~1 0 r~ r~ rl O l N
a o _ _ O -- N ~D O O O O O _ _ r~l
r ~ ~ w ~ ~
I ~ o~ u) o o ~ a~ ,~ rl O O
¦ U 01 l l O ~p N l N 11~ O O O r~ O l N
_ _ _ _ _ _ _ _~ _ ~1 0 r~ 1~ _ _
O _ O _ ql N r~ _ r~ O O O r1 O _ N
F~ a~ ~~1 Ll') r~l r1 O rl O
_ _ O _ _ N N _ _ _ _ O O _ O _ N
.1 0 ~ 1 ~ r
z ~ ~ ,, ~ ~ l. ~ ~, 0~O a) ~ ~
~ S-l O r-l _ r _ N ri 1~ r~ ~ -rl r Cq
O ~ R ~ R ~ ol X ~ Fj~l O ~ u ~ h H -rl
~H _ _ c ~-) z; _ E~ _ _ a _ ~ _ _ _ _
2~7~?~
= ~ = = _ = = _ = _
Ul ~D 1~, ~ ~ ~ ~ O .
l O ,, ,, ~ ~ ~ ~ æ
_ _ ._ __ _ M _ M _ _
~p Ul r~ 00 ~ ~ 'Y3 ~ 0 ,tn
~ o ,1 ~1 ,J a~ c~l ~`I ~ 1~
_ _ _ _ _ _ _ _ _ _
It) rl I~ 'Y3 ~ ~ ~
O ~O ~) . ~ ~ ~)
_ O rl ~1 ~ N _ ~;
11~ ~ ~` 3 ~)
_ O ,, ~ ~ _ _ l æ .~
Ot) t` M Ul _ _ t`~
O~ ~ ~ ~ Ul .~
_ _ O _ _ N _ __ _ _
~O tO ~1
a~ I
a~ IY) 3 3 Q~ .
l l O ~i O~ ~ l l ~
u~ i~ o ~ 1~4 ~
~ I .,1 .,1 .,1 .,1 ~ ~
-,~ J ~ ~ ~1 ~1 1~ ~1
~ w x a w w w w ~ w
.~
2~70~
Formulations A, B, C, D, E and F are prepared by first
forming a uniform dispersion of the Carbopol 614 or 940
thickener in 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 using a mixer equipped with a premier
blade, with agitation set at a medium shear rate, as
recommended by the manufacturer. After mixing for 15
minutes, the dispersion is then neutralized by addition, under
the same mixing, of the caustic soda (50% NaOH) component
until a thickened product of gel-like consistency is formed (
10 minutes).
To the resulting gelled dispersion the silicate, sodium
tripolyphosphate (NaTPP), tetrapotassium pyrophosphate (TKPP),
or potassium tripolyphosphate (KTPP), the surfactant emulsion
(described below) and bleach and color, added sequentially, 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
is cooled to from 90-95F before the bleach i9 added.
Separately, the surfactant emulsion of the phosphate
anti-foaming agent (LPKN), stearic acid or fatty acid mixture
and detergent (Dowfax 3B2) is prepared by adding these
ingredients to the remainin~ 3% of water and heating the
resulting mixture to a temperature in ~he range of 160F
(71C). In formulation E, the Acrysol LMW 45-N may be added at
this stage.
46
3 ~ s~ ~
The rheograms for the Eormulations A, ~3, C, D, E and F
are shown in figures 1-6, respectively.
These rheograms are obtained with the System 4 Rheometer
from Rheometrics e~uipped with a Fluid Servo with a 100 grams-
centimeter torque transducer and a 50 millimeter parallelplate geometry having an 0.8 millimeter gap between plates.
All measurements are made at room temperature (25~1C) in a
humidity chamber after a 5 minute or 10 minute holding period
of the sample in the gap. The measurements are made by
applying a frequency of 10 radians per second.
All of the composition formulations C, D and F exhihit
linear viscoelasticity as seen from the rheograms of figure 2-
6. No phase separation at from ambient temperature to 140~F
were observed for any of the formulations for at least the
minimum number of weeks re~lired to satisfy the criteria
stability 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 sufficiently large size crystals which
separated to the bottom of the composition. Also, as seen in
figures 1 and 2 formulations A and B are not linear
viscoelastic, at least within the preferred criteria as
previou~qly described. Formulations C, D, E and F, according
to the invention did not undergo any crystal growth.
For the bottle residue test, each formulation is allowed
to age for 1 week at ambient temperature in a standard 32
ounce small necked polyethylene bottle. An amount of product
2 ~
is poured from the bottle to fill a standard sized dispenser
cup of an automatic dishwasher. The bottle is then replaced
in an upright position and is retained in the upright position
for at least 15 minutes. This procedure of filling the
dispenser cup, placing the container in the upright position
and waiting at least 15 minutes is repeated until no more
product flows from the bottle. At this time, the weight of
the bottle is measured. Bottle res:idue is calculated as
Wf x 100
Wo
Wo is the initial weight o~ the ~illed bottle and Wf is the
final weight of the filled bottle. The bottle residue for
each formulation A-F iY 4 to 5~. Formulations C-F have
viscosities of from 10,000 to 20,000 measured with a
Brookfield LVT viscometer, ~4 spindle at 20 rpm measured at
80F. All of these products are easily pourable from the
polyethylene bottle.
Example 6
A Carbopol 614 slurry is formed as described in Example 1
except that the coloring agent is first added to the deionized
water ( 92~ of the total added water) and the amounts of the
ingredients are changed as shown below. The premix
(surfactant emulsion) of the surface acti~e ingredients i9
also formed as in Example 1 using stearic acid as the fatty
acid stabilizer and the remaining 8~ of the total added water.
The ingredients are then mixed together with the Carbopol
6i4 slurry in the following order: alkali metal silicate,
NaTPP (powder), KTE'P (powder), surfactant emulsion, bleach and
48
2 ~ 7 ~ ~J ~
perfume. The resulting composition is obtained with the
following ingredients in the following amounts:
Ingredient Amount (wt. ~)
Deionized water q.s. 100.00
Carbopol 614 1.00
NaOH (38% Na2O) 6.38
Na silicate (1:24)(47.5~) 20.83
KTPP (anhydrous) powder 20.35
NaTPP (3~ H2O) 5.26
Dowfax 3B2 0.80
LPKN 0.16
Stearic acid 0.15
Bleach (Na hypochlorite-13~) 9.23
CI Pigment Green 7 (CI 74260) 0.0024
Highlights (fragrance) 0.05
The composition has a pH of 11.3 + 0.1 and density (9p .
gr.) of 1.39 -~ 0.03. The viscosity at 80F measured with a
~rookfield LVT viscometer at 20 rpm with a #4 spindle is
12,000 + 2,000.
All of the preferred criteria as set forth in Table A
above are satisfied.
~QrJ~O~
Example 7
The Eollowing formulas were prepared according to the
procedure of Example 1 and tested.
. _
I 1 _ 2 _ 3 -4
¦Water _ q.a. q.a. q.a. q.a
¦Carbopol 941 0.9
_ ~ _ ._
¦Carbopol 940 0.9
~ ~ ... _
¦Carbopol 614 0.9 0.9
I _ _
¦NaOH 4.5 4.5 4.5 4.5
Na-Silicate 21 21 21 21
1 TKPP 15 15 15 15
.__~ . __ . _ ~_
Na-TPP Anhy. 13 13 13 13
.__ _ _ . _ _ . ._ ..
NaOC1 (1.0 Av. Chlorine) 7.5 11.1 11 11
. ._ . _
.
LPKN 158 0.16 0.16 0.16 0.16
Dowfax 3B-2 1 0.8 _ 0.8 0.8
l .__
_ . _ .. _ ~. __
l Sa (Emery 132) 0.2
_ __ , ... _ .... ___
Syncro Wax Acid (Cl836) - 0.2 -
Syncro Wax Acid (C~36) 0.1 0.2
_ .~ .. ,
Air (~ v/v) c 2.0 c 2.0 ~ 2.0 c 2.0
__ .__ . .__
Vis. 0 wk. R.T. 8600 7020 8000 8000
_ ~ . . ,._ ._ , _
Vis. 6 wks~. R.T. 4200 _ 6000 7100 8000
Vis. 6 wk9. at 100F 3200 __ 5920 9100 9350
Phase separation RT Slight Sep. Stable Stable Stable
, . .___ ._ _
Stability 100F Unstable Stable Stable Stable
r~ ~ ~3 1
~ ~ ~ ~ ~ ~ ~ ~_ _ _ ~_ _ ~a
Ln o o C` ~ ~ ~ _
1~ O ~ (~ r~ 00 r~l O O Ln Ln O O
H O _ _ _ O O . _ r` _ O O _
cL~n d~ (~l r~ cO ri O O In Ln Ln O
~ o ~ rl ~ 1~ o ~ ~1 c~ c~ ~ o o~
_ _ _ _ _ _ _ . ___ __ __ O
C!~ Ln r-l N r~ O r-l r l O C` C In r-l
_ _ _ _ _ _ ____ _ _ _ O
Ln In ~ ~ rl O r-l Ln r-l Ln C Ln r l O
. _~ O ~ ~`l rl O N O r' ul In -- ~`i o ~
- - - - - - - - - #
Ln O ~ ~ r-l a~ O O O Ln Ln L~ O ~ Lrt)
~ Ot`l ~`1 ~ O O r l O t~ t~ Ln ~1 r-l
_ Ln _ _ _ _ o o o _ Ln ~. _ _ O s~
_ C~O ~ ~ r~ r-l L j r-l Ln t~ r~ r-l CU
Ln _ _ _ _ _ OO O _ Ln _ _ O r~ O
tq O Lll ~ N r-l O ri r-l N Ln ~l r-l r~
_ _ _ _ _ _ _ _ _ __ _ _ _ O
cn ~ N rl a~ O O O Ln Ln ~1 ~OI
O O N ~1 O O r-l Ln rl ~ ~ r; r-l
_~ ~ ~ ~ _ _ _ h _~ #: __ ~3
Z; li~ ~ g ~ 'O
r-l L o\~ H ~q H ~ ~C O E~ H
O O ~ Ln v ~ E~ Ln H O E~ O P~ H ~Zj H r-l
~ V O ~ h O H O ~ H 111 O r-t ~ V H W O
V ~ ~ ~ ~q ~ U~~ ~ P~ V~ ~ U~`~ ~ ~ ~ ~ _~
_~ ~ 3~_ ~ ~_ __ _ _ _~2 _ _
Example 8
The ,llowing formulars A-B were prepared accordinq to the
procedure oE Example 1.
A B
~__ ____ I
CARBOPOL 614 1 0 1 0
_ I
NaOH (50~) 4 5 4 5 l
LPKN 158 3 2 3 2 I
_
STEARIC ACID 0.06 0 06
. _
DOWFAX 3B-2 0 8 0 8 l
._ _._ ._
SODIUM SILICATE (47.5~) _ 20.83 _ 20.83 __
POTASSIUM TRIPOLYPHOSPHATE 20.35 20.35
. _ _ . _ _ .,_
SODIUM 3% H20 TRIPLOYPYPHOSPH~TE 5.26 _ 5.26
SODIUM HYPOCHLORITE (13~) 10.13 _ 10.13
WATER 36.877 36 877
, . .. _ . __ -- -- I
CI DIRECT YELLOW 28 0.003
HIGHLIGHTS III PERFUME O.05 O.03
. . _ ~
DENSITY 1 30
._ . _ _
VISCOSITY 12 100
~rookfield viscosity measured at room temperature at #4 spindle
at 20 rpms.
52
