Note: Descriptions are shown in the official language in which they were submitted.
2 & ~
IR 46810
AQUEOUS LIQUID DETERGENT COMPOSITION,
HAVING A POLYMERIC THICKENER
Background of the Invention
Liquid automatic dishwasher detergent compositions both
aqueous and nonaqueous, have 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.
Howe~er, even the best of the currently available liquid
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 patent art in this area includes 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 4,597,889i
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 aqueous
detergent compositions include U.S. Patent 3,985,668; U.K.
Patent Applications GB 2,116, l99A 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
2 ~ 3 rj
;Dixit); IJ.S. Patent 4,889,6S3 (Ahmed, et al.). Commonly
assigned co-pending patents include, for example, S
42~,912 filed October 24, 1989; Serial No. 324,385, filed
~ctober 29, 1986; Serial No. 323,138, filed March 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 potassium salts on sodium
tripolyphosphate in aqueous detergent compositions is
described in U.S. Patent 3,720,621 (Smeets).
U.S. Patent 4,836,948 discloses a viscoelastic gel
detergent composition characterized by its viscosity under low
and high shear conditions, pH, and steady state viscoelastic
deformation compliance. The recently issued U.S. Patent
4,8S9,358 discloses the incorporation of metal salts of long
chain hydroxy fatty acids, as anti-tarnishing agents, in
thickened aqueous automatic dishwashing detergent
compositions.
Brief DescriPtion of the Drawinqs
Figures 1-6 are rheograms, plotting elastic modulus G'
and viscous modulus G" as a function of applied strain, for
the compositions of Example 1, Formulations A, B, C, D, E and
F, respectively.
Summary of the Invention
~ccording to the present invention there is provided an
improved aqueous liquid automatic dishwasher detergent
composition. The composition is characterized by its
2~ 3
-i~bstantially indefinite stability against phase separation or
settling of dissolved or suspended particles under high and
low temperature conditions, low levels of bottle residue,
relatively high bulk density, and substantial absence of
loosely bound water, but also by its overall product
consistency from batch to batch and run to run and over a wide
range of storage and aging conditions, including superior
aesthetics, freedom from Eish-eyes, absence of crystal
formation and growth, and resistance to cup leakage. The
linear viscoelastic aqueous ~iquid automatic dishwasher
detergent comprises, by weight,
(a) 5 to 40% of at least one alkali metal detergent
builder salt;
~ b) 0 to 20% alkali metal silicate;
(c) 0 to 6% alkali metal hydroxide;
(d) Optionally, 0 ts 5% chlorine bleach stable, water-
dispersible organic detergent active material;
(e~ 0 to 1.5% chlorine bleach stable foam depressant;
(f) chlorine bleach compound in an amount to provide 0.2
to 4% of available chlorine;
(g) 0.1 to 2.0% of at least one hydrophilic cross-linked
water insoluble polyacrylic acid thickening agent having a
molecular weight of from 800,000 to 4,000,000 to provide said
linear viscoelastic property;
(h) 0.01 to 2.0% of long chain fatty acid or a metal
salt of a long chain fatty acid as a physical stabilizer to
increase the physical stability of the composition;
2 ~
(i) v t~ l0-O of a llorl-cross-linked polyacrylic acid
having a molecular weight in the range of from 800 to 200,000;
and
(j) water;
and wherein at least 98 weight % of the water is bound to the
polyacrylic acid thickening agent.
In another aspect of the invention, a method for
preparing the aqueous composition is provided. According to
this aspect, the method comprises the steps of
I. ~a) fully hydrating the cross-linked polycarboxylate
thickener by slowly adding the thickener to heated water while
moderate agitating the mixture.
(b) slowly adding a neutrali~ing amount of caustic soda
to the mixture from (a) while continuing agitation to obtain a
dispersion of the neutralized thicke~er;
II. (c) forming an aqueous mixture of surface active agents;
(d) heating the mixture in (c) to a temperature higher
than that of the heated water in (a) and mixing until a
homogeneous smooth premix is obtained;
III. (e) uniform].y mixing alkali metal builder salts 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 step (a), and
(h) adding bleach to the mixture (g).
In a preferred embodiment of the invention process, the
pH of the agueous slurry of the cross-linked polycarboxylate
2 ~ 3 ~
~hickener after the neutralization in step (b) and in each
succeeding step is maintained at a value of at least 11.
Detailed Description and Preferred Embodiments
The compositions of this invention are thickened aqueous
liquids containing various cleansing active ingre~ients,
detergent builder salts and other detergent adjuvants,
structuring and thickening agents and stahilizing components,
although some ingredients may serve more than one of these
functions.
The advantageous characteristics of the compositions of
this invention include physical stability, as manifested by
little or no phase separation, solid settling or viscosity
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 characteristics
and performance, and superior aesthetics. These
characteristics are believed to be attributed to several
interrelated factors such as low solids, i.e. undissolved
particulate content, product density and linear viscoelastic
rheology. These factors are, in turn, dependent on several
critical compositional components and processing conditions of
the formulations, namely, (a) the inclusion of a thickening
effective amount of a temperature, bleach and salt stable
cross-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
2 ~
chain fatty acid or salt thereof, and (3) a product bulk
density of at least 1.28 g/cc, especially at least 1.32 g/cc,
(4) hydrating the cross-linked polymeric thickener with heated
water, and (5) maintaining the pH of the neutralized polymeric
thickener at a pH of at least 11, preferably at least 11.5.
In particular, the aqueous liquid automatic dishwasher
detergent compositions of this invention will, at least in the
preferred embodiments, satisfy each of the following stability
criteria over the aging temperature-time schedule shown by the
following Table A:
TABLE A
Aging Temperature Duration
(F) (Weeks)
_
Minimum Preferred
140 > 1 > 2
120 > 6 > 8
100 > 13 > 16
Ambient > 24 > 24
More specifically, the compositions are considered stable if
each of the following stability criteria is satisfied for at
least the minimum number of weeks for each aging temperature
shown in Table A:
o no visible phase separation (i.e. no
solid/liquid separation)
o no significant change (e.g. less than 10%) in
viscosities, yield stress or other dynamic-mechanical
properties
o no crystal growth under repeated heating-
cooling cycles over a temperature range of at least 7F to
140F
2 ~ 3 ~
~ decolorization or significant color change.
in addition to the above stability criteria, the compositions
of this invention are further characterized by their low
bottle residue. Specifically, for the preferred cross-linked
polyacrylic acid thickened compositions of this invention,
bottle residues, under the usual use conditions, will be no
more than 6 to 8%, preferably no more ~han 4 to 5%, of the
original bottle contents, on a weight basis.
The polymeric thickenin~ agents contribute to the
gel-type rheology of the invention compositions. As used
herein, "linear viscoelastic" or "linear viscoelasticity"
means that the elastic (storage) moduli (G') and the viscous
(loss) 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 to 80%.
More specifically, a composit,on is considered to be linear
viscoelastic for purposes of this invention, if over the
strain ranye 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
of 0 to 80%. Typically, the variation in 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'
(tan ~) is less than 1, preferably less than 0~8, but more
than 0.05, preferably more than 0.2, at least over the strain
2 ~ 3 ~
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 f~rther 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 of the amount of energy
dissipated as heat when strain is applied. Therefore, a value
of tan ~,
0.05 < tan ~ < 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 linear viscoelastic characteristic, 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
2 ~ 3 ~
characterizes the invention compositions. The linear
viscoelaslic 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. Linear viscoelasticity also
contributes to the elimination of dripping of the contents
when the product is poured from a bottle and hence reduction
of formation of drops around the container mouth at the
conclusion of pouring the product from a container.
A still further attribute of the invention
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 virtually all of
the aqueous vehicle component appears to be held tightly bound
to the polymer matrix. Therefore, there appears to be no or
substantially no free water present in the invention
compositions. This apparent absence of free water (as well as
the cohesiveness of the composition) is manifested by the
observation that when the composition is poured from a bottle
onto a piece of water absorbent filter paper virtually no
water is absorbed onto the filter paper over a period of at
least several hours or longer and, furthermore, the mass of
the linear viscoelastic material poured onto the filter paper
will retain its shape and structure. As a result of the
absence of loosely bound water, there is virtually no phase
separation between the aqueous phase and the polymeric matrix
2~
or dissolved solid particles. This characteristic is
manifested 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. The preferred compositions have remained stable
for period in excess of 6 months and more.
In order to maximize physical (phase) stability, the
density 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 was achieved, according to our earlier
invention, by providing the composition with a bulk density of
at least 1.32 g/cc. A density of 1.42 g/cc is essentially
equivalent to zero air content.
It is important to note that the bulk density of the
product can be adjusted by controlling the degree of aeration,
as well as total solid content. Further, the dispersed air
bubbles also contribute to the viscoelastic property of the
prcduct.
However, it has now been found that air bubble
incorporation is not required to achieve stabilization and, in
fact, we have been able to prepare stable thickened products
with densities as low as 1.28 g/cc. At densities below the
1.28 cc/g, however, the flowability of the product tends to be
degraded and the large air bubble content tends to cause the
composition to be too highly translucent or cloudy to opaque.
Therefore, the product density is preferably selected in the
2~ 3
l-ange of 1.,8 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 ranges
air bubble incorporation is determined to achieve the desired
product aesthetic appearance and flow characteristics.
It has previously been found in connection with
other types of thickened aqueous liquid, automatie dishwasher
detergent compositions that agglomeration or escape of
incorporated air bubbles could be avoided by incorporating
certain surface active ingredients, especially higher fatty
acids and the salts thereof, such as stearic acid, behenie
acid, palmitic acid, sodium stearate, aluminum stearate, and
the like.
Therefore, in the present invention, in order to
avoid stabilization of air bubbles whieh may become
incorporated into the compositions during normal processing,
sueh as during various mixing steps, is avoided by post-adding
the surfaee aetive ingredients to the remainder of the
eomposition, under low shear eonditions using mixing deviees
designed to minimize eavitation and vortex formation.
As will be deseribed in greater detail below the
surface aetive ingredients present in the eomposition will
inelude anti-foaming agent (e.g. phosphate ester) and higher
fatty aeid or salt thereof as a physieal stabilizer and
optionally a detergent surfaee aetive cleaning agent.
Exemplary of the polyearboxylate type thiekening
agents are eross-linked polyaerylic aeid-type thiekening
agents sold by B. F. Goodrich under their Carbopol trademark,
including both the 900 series resins, especially Carbopol 941,
2 ~ 3 ~j
which is the most ion-insensitive of this class of polymers,
and Carbopol 940 and Carbopol 934, and the 600 series resins,
especially Carbopol 614. The Carbopol 900 series resins are
hydrophilic 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:
~ H H
~----C ------~ -- C --------~--
H
/ \\
HO O n.
Carbopol 941 has a molecular weight of 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 resins are cross-linked with polyalkenyl polyether,
e.g. 1% of a polyallyl ether of sucrose having an average of
5.8 allyl groups for each molecule of sucrose. The
preparation of this class of cross-linked carboxylic polymers
is described in U.S. Patent 2,798,053. Further detailed
information on the Carbopol 900 series resins is available
from B. F. Goodrich, see, for example, the B. F. Goodrich
catalog GC-67, Carbopol'~' Water Soluble Resins.
~n general, these thickening resins are preferably
copolymers of a water dispersible copolymer of an alpha-beta
monoethylenically unsaturated lower aliphatic carboxylic acid
cross-linked with a polyether of a polyol selected from oligo
saccharides, reduced derivatives thereof in which the carbonyl
group is converted to an alcohol group and pentaerythritol,
the hydroxyl groups of the polyol which are modified being
2 ~ 3 ~
etherified with allyl groups, there being preferably at least
two such allyl groups per molecule.
These water-dispersible cross-linked thickening
resins as described in the aforementioned U.S. Patent
2,798,053 and which have been commercialized by B. F. Goodrich
as the Carbopol 900 series resins are prepared from
essentially linear copolymers. More recently, B. F. Goodrich
has introduced the Carbopol 600 series resin. These are high
molecular weight, non-linear polyacrylic acid cross-linked
with polyalkenyl ether. In addition to the non-linear or
branched nature of these resins, they are also believed to be
more highly cross-linked than the 900 series resins and have
molecular weights between 1,000,000 and 4,000,000. Mixtures
of two or more Carbopol resins can be used in the composition.
Most especially useful of the Carbopol 600 series
resins is Carbopol 614 which is the most chlorine bleach
stable of this class of thickening resins. Carbopol 614 is
also highly stable in the high alkalinity environment of the
preferred li~uid automatic dishwasher detergent compositions
and is also high stable to any anticipated storage temper~ture
conditions from below freezing to elevated temperatures as
high as 120F, preferably 140F, and especially 160F, for
pexiods of as long as several days to several weeks or months
or longer.
While the most favorable results have now been
achieved with Carbopol 614 polyacrylic resin, other linear or
branched cross-linked polycarboxylate-type thickening agents
can also be used in the compositions of this invention. As
used herein "p~lycarboxylate-type" refers to water-soluble
carboxyvinyl polymers of alpha,beta monoethylenically
unsaturated lower aliphatic carboxylic acids, which may be
- linear or non-linear, and are exemplified by homopolymers of
S acrylic acid or methacrylic acid or water-dispersible or
water-soluble salts, esters or amides thereof, or water-
soluble copolymers of these acids or their salts, esters or
amides with each other or with one or more other ethylenically
unsaturated monomers, such as, for example, styrene, maleic
acid, maleic anhydride, 2-hydroxyethylacrylate, acrylonitrile,
vinyl acetate, ethylene, propylene, and the like, and which
have molecular weights of from 500,000 to 10,000,000 and are
cross-linked or interpolymerized with a multi-vinyl or multi-
allelic functionalized cross-linking 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 500,000
to 10,000,000, preferably 750,000 to 5,000,000, especially
from 1,000,000 to 4, aoo, ooo, and by their water solubility,
genexally 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 as described
above), and the like. Typically, amounts of cross-linking
agent to be incorporated in the final polymer may range from
0.01 to 5 percent, preferably from 0.05 to 2 percent, and
especially, preferably from 0.1 to 1.5 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 or non-linear polymeric
compound while maintaining the cross-linked polymer at least
water dispersible and highly water-swellable in an ionic
aqueous medium.
The amount of at least one high molecular weight,
cross-linked polyacrylic acid or other high molecular weight,
hydrophilic cross-linked polycarboxylate 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 agent, ionic strength of the
composition, hydroxyl donors and the like.
Specific examples of detergent builder salts used in
the instant composition include the polyphosphates, such as
alkali metal pyrophosphate, alkali metal tripolyphosphate,
alkali metal metaphosphate, and the like, for example, sodium
or potassium tripolyphosphate (hydrated or anhydrous),
tetrasodium or tetrapotassium pyrophosphate, sodium or
potassium hexa-metaphosphate, trisodium or tripotassium
orthophosphate and the like, sodium or potassium carbonate,
sodium or potassium citrate, sodium or potassium
nitrilotriacetate, and the like.
In accordance with one embodiment of the present
invention to prepare a translucent composition, the detergent
builder salts will be comprised of mixtures of at least
potassium tripolyphosphate ~KTPP) or potassium pyrophosphate
and sodium tripolyphosphate (NaTPP) (especially hexahydrate).
Typical ratios of KTPP to NaTPP are from about 1.4:1 to 10:1,
especially from 2:1 to 8:1. The total amount of detergent
builder salts is preferably from 10 to 35% by weight, more
preferably from 15 to 35%, especially from 18 to 30% by weight
of the composition. Of this total amount of the detergent
builders at least 50% by weight (preferably at least 8% by
weight of the composition) will be KTPP and preferably at
least 5% by weight (preferably at least 2% by weight of the
composition) will be NaTPP. More preferably, the alkali metal
detergent builder salt will be comprised of from 65 to 95% of
KTPP, especially 75 to 90% of KTPP and from 5 to 35%,
especially 10 to 25% of NaTPP. In terms of the total
composition, the amount of KTPP will be in the range of from 8
to 25%, preferably 15 to 22% by weight, and the amount of
NaTPP will be in the range of from 2 to 10%, preferably 3 to
8% by weight.
An opaque composition can be prepared by the use of
sodium tripolyphosphate or a mixture of sodium
tripolyphosphate and potassium tripolyphosphate or potassium
16
2 ~ 3 3
pyrophosphate wherein the ratio of sodium tripolyphosphate to
either potassium tripolyphosphate and/or potassium
pyrophosphate is 100/1 to 1.01/1, more preferably 100/1 to
- 1.05/1. In other words, there is an excess of sodium ions to
potassium ions in the composition.
The 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 hypothesized
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 10 to 50 carbon atoms, more
preferably from 12 to 40 carbon atoms, and especially
pref~rably from 14 to 40 carbon atoms, and most preferably
about 20 to 40, 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
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,
~$~3~
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.
It has, however r also recently been discovered by
some of us and others 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 Cl8 to C40. 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 about 20
to 32 carbon atoms, especially 24 to 30 carbon atoms and
mixture of fatty acids encompassing this range are preferred.
lS 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 di- and tri-
valent metals of Groups IIA, IIB and IIIB, such as magnesium,
calcium, aluminium and zinc, although other polyvalent metals,
including those of Groups III~, IVA, VA, IB, IVB, VB, VIIB and
18
2 ~
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 pentavaler.t
state. Naturally, for use in automatic dishwashers, as well
as any other applications where the invention composition will
or may come into contact with articles used 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 acid salt stabilizing agents in the range of from 0.02
to 2% preferably 0.04 to 1%, more preferably from 0.06 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.
19
2 ~
Depending on the amounts, proportions and types of
fatty acid physical stabilizers and polyacrylic acid-type
thickening agents, the addition of the fatty acid or salt not
only 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 0.01 - 2.0 weight percent fatty acid and salt from 0.1 -
2.0 weight percent polymeric thickening agent are usually
sufficient to provide these simultaneous benefits and,
therefore, the use of these ingredients in these amounts is
more preferred.
In order to achieve the desired benefit from the
fatty acid or fatty acid salt stabilizer, without
stabilization of excess incorporated air bubbles and
consequent excessive lowering of the product ~ulk density, the
fatty acid or salt should be post-added to the formulation,
preferably 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 a~ueous phase. To achieve the desired fine
emulsification 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 example, for stearic acid having a melting point of 68 -
69C, a temperature in the range of between 50C and 70C will
2 ~ 3 ~
be used. For lauric acid (m.p.=47C) an elevated temperature
of 35 to 50C can be used.
Foam inhibition is important to increase dishwasher
machine efficiency and minimize destabilizing effects which
might occur due to the presence of excess 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 foam-producing component. The degree of foam is also
somewhat dependent on the hardness of the wash water in the
machine whereby suitable 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 is generally preferred to include a chlorine
bleach stable foam depressant or inhibitor. Particularly
effective are the alkyl phosphoric acid esters of the formula
Jol
HO -~P - R
OR
and especially the alkyl acid phosphate esters of the formula
HO~ P--- OR
~R
In the above formulas, one or both R groups in each type of
ester may represent independently a Cl2-C20 alkyl or
ethoxylated alkyl 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 6
moles, more preferably 3 or 4 moles, ethylene oxide can also
3 3 ~
be used. Some examples of the foregoing are commercially
available, such as the products SAP from Hooker and LPKN-158
from Knapsack. Mixtures of the two types, or any other
chlorine bleach stable types, or mixtures of mono- and di-
esters of the same type, may be employed. Especially
preferred is a mixture of mono- and di-ClG-Cl8 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 0.05 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 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
dichloroisocyanurate, dichloro-dimethyl hydantoin, or
chlorinated TSP, alkali metal or alkaline earth metal, e.g.
potassium, lithium, magnesium and especially sodium,
hypochlorite is preferred. The composition should contains
sufficient amount of chlorine bleach compound to provide 0.2
to 4.0% by weight of available chlorine, as determined, for
example, by acidification of 100 parts of the composition with
2 ~
~xcess hydrochloric acid. A solution containing 0.2 to 4.0%
by weight of sodium hypochlorite contains or provides rcughly
the same percentage of available chlorine. 0.~ to 1.6% by
weight of avai]able chlorine i5 especially prefexred. For
example, sodium hypochlorite (NaOC1) solution of from 11 to
13% available chlorine in amounts of 3 to 2~%, preferably 7 to
12%, can be advantageously used.
Another surprising and unexpected benefit and
advantage of the preferred Carbopol thickened compositions of
this invention is the essentially total masking of any
chlorine bleach odor which is characteristic of, for example,
the prior known clay thickened products. By virtue of the
masking of chlorine bleach odor, it has been found that the
subject compositions can be blended with substantially lower
amounts of fragrance, e.g. lemon oil fragrance, to achieve the
same or superior olfactory sensation for the consumer. For
instance, as little as 0.05% of lemon fragrance will have the
same effect as 0.12% in clay thickened products.
Furthermore, the addition of fragrance does not
adversely affect the stability criteria, as previously
defined, such as viscosity or phase stability, of the
composltions.
Detergent active material which are optionally
useful herein should be low-foaming and stable in the presence
of chlorine bleach, when present, especially hypochlorite
bleach, and for this purpose those of the organic anionic,
nonionic, amine oxide, phosphine oxide, sulphoxide or betaine
water dispersi~le surfactant types are preferred, the first
~ ~ ~ e~ ( ~ 3 ~
mentioned anionics being most preferred. Particularl~
preferred surfactants herein are the linear or branched alkali
metal mono- and/or di-(C8-Cl4) alkyl diphenyl oxide mono-
and/or di-sulphates, commercially available for example as
DOWFAX tregistered trademark) 3B-2 and DOWFAX 2A-l. In
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 C1O_C1~
alkylsulphates such as sodium dodecylsulphate and sodium
tallow alcoholsulphate; sodium C1O_C1~ alkanesulphonates such
as sodium hexadecyl-l-sulphonate and sodium Cl2-Cl8
alkylbenzenesulphonates such as sodium
dodecylbenzenesulphonates. The corresponding pota~sium salts
may also be employed.
As other suitable surfactants or detergents, the
amine oxide surfactants are typically of the structure R2RlNO,
in which each R represents a lower alkyl group, for instance,
methyl, and Rl represents a long chain alkyl group having from
8 to 22 carbon atoms, for instance a lauryl, myristyl,
palmityl or cetyl group. Instead of an amine oxide, a
corresponding surfactant phosphine oxide R2RlPO or sulphoxide
RRlSO can be employed. Betaine surfactants are typically of
the structure R2RlN+R"COO-, in which each R represents a lower
alkylene group having from 1 to 5 carbon atoms. Specific
examples of these suractants include lauryl-dimethylamine
oxide, myristyl-dimethylamine oxide, the corresponding
24
2 ~
phosphine oxides and sulphoxides, and the corresponding
betaines, 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.
Surfactants of the foregoing type, all well known in
the art, are described, for example, in U.S. Patents 3,985,668
and 4,271,030. If chlorine bleach is not used then 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 of the composition, although smaller or larger
amounts, such as up to 5~, such as from 0.1 to 5%, preferably
from 0.3 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 having
Na20:SiO2 or K20- sio2 ratio of 1:1.3 to 1:2.8, especially
3 ;3
preferably 1:2.0 to 1:2.6. At this point, it should be
mentioned that many of the other components of this
composi.tion, especially alkali metal hydroxide and bleach, are
- also often added in the form of a preliminary prepared aqueous
dispersion or solution. However, unless otherwise noted, when
amounts of a particular ingredient are given, the reference is
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 salts, which all contribute to the cleaning
performance, it is 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 composition 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, potassium
tripolyphosphate, and alkali metal silicate, however, it is
usually necessary to include alkali metal hydroxide, e.g. NaOH
or KOH, to achieve the desired high alkalinity. Amounts of
alkali metal hydroxide in the range 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 ~/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, especially for the
Carbopol class 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 least 11.5. Furthermore, these high
alkalinity levels should be maintained throughout the product
formulation steps, namely, the pH value of at least 11,
preferably at least 11.5, should be maintained during the
successive additions of the other ingredients of the
competition.
As will be shown by the examples given below, if the
pH drops to a lower value, there is a loss in viscosity, as
well as stability (as manifested by liquid phase separation)
over time.
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.
Another often beneficial additive for the present
liquid automatic dishwasher detergent compositions is a
2~ 7
rclatively low molecular weight, non-cross-linked polyacrylic
acid or neutralized with caustlc, such as the commercial
product Acrysol LMW=45N, which has a molecular weiyht of
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 contribute
to reduced spotting or streaking and reduced filming on
dishes, glassware, pots, pans, and other utensils a~d
appliances.
Generally, a suitable molecular weight ranges for
the non-cross-linked polyacrylic acid is from 800 to 200,000,
preferably 1000 to 150,000, especially from 2,000 to 100,000.
When present in the formulation, the non-cross-linked
polyacrylic acid can be used in amounts up to 10% by weight,
preferahly from 1% to 8% by weight, especially 2 to 6% by
weight of the composition.
Other conventional ingredients may be included in
these compositions in small amQunts, generally less than about
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
alkalinity. Especially preferred for coloring are the
chlorinated phthalocyanines and polysulphides of
aluminosilicate which provide, respectively, pleasing green
and blue tints. To achieve stable yellow colored products,
the bleach stable mixed dyes C.I. Direct Yellow 28 (C.I.
28
2 ~Y ~
19555) or C.I. Direct Yellow 29 (C.I. 19556) can be added to
the compositions. These colors meet stability criteria
described in Table A. TiO2 may be employed for whitening or
neutralizing off-shades.
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 amounts of
finely divided air bubbles, generally up to about 10% by
volume, preferably up to 4% by volume, more preferably up to
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 100
microns in diameter, preferably from 20 to 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 these compositions
should, of course, be neither so 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 diminished or destroyed by increasing tan
1. Such amount is readily determined by routine
experimentation in any particular instance, and generally will
range from 30 to 75 weight percent, preferably 35 to 65 weight
percent. Preferably, the water should also be deionized or
softened.
The manner of formulating the invention compositions
is also important. As discussed above, the order of mixing
~ ~ r~ 3 ~;
the ingredients as well dS the manner in which the mixing is
performed will generally have a significant effect on the
properties of the composition, and in particular on product
density (by incorporation of more or less air), viscosity and
physical stability (e.g. phase separation). Thus, according
to the preferred practice of this invention the compositions
are prepared by forming a dispersion of the polycarboxylate
type thickener in heated water, e.g. 35 to 60C (95 to
140F), preferably 40C to 50C (104 to 122F), under
moderate to high shear conditions, neutralizing the dissolved
polymer to a pH of at least 11, preferably at least 11.5, such
as from 11.5 to 13.0, to cause gelation. After transferrin~
the thickener dispersion to a main mixing tank processing is
continued by introducing, while continuing mixing, the
detergent builder salts, alkali metal silicates, chlorine
bleach compound and remaining detergent additives, including
any previously unused alkali metal hydroxide, if any, other
than the surface-active compounds. All of the additional
ingredients can be added simultaneously or sequentially.
Preferably, the ingredients are added sequentially, with
mixing continued for from 2 to 10 minutes for each ingredient,
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 at different times. These mixing
steps should also be performed under moderate to high shear
rates to achieve complete and uniform mixing. These
additional ingredient mixing steps may be carried out at room
2~g~^3
temperature, but preferably the elevated temperature of the
thickener slurry is maintained. 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, optionally, organic detergent
compound, and fatty acid or fatty acid salt stabilizer is
post-added to the previously formed mixture in the form of an
a~ueous 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 about Tm to Tm+10, where Tm is the
melting point temperature of the fatty acid or fatty acid
salt. For the stearic acid stabilizer the heating temperature
is in the range of lS0 ~o 170F (6S to 77C). For the high
chain length fatty acids and mixtures C1~_C3G~ correspondingly
higher temperatuxes may be used, such as from about 160 to
200F (ca. 70 to 95C). However, if care is 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
2S be less important.
In accordance with an especially preferred
embodiment, the thickened linear viscoelastic aqueous
2 ~
automatic dishwasher detergent composition of this invention
includes, on a weight basis:
(a) (i) 8 to 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 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%, prefera~ly 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 oE from 750,000 to 4,000,000, preferably
800,000 to 3,000,000, thickening agent is present at a
25 concentration of 0.1 to 2%, more preferably from 0.2 to 1.5%,
and most 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
2 ~
physical stability of the compositions, preferably from 0.01
to 0.2%, more preferably from 0.1 to 1.5%;
(i) 0 to 10%, preferably 1 to 8%, especially 2 to
6% of non-cross-linked polyacrylic acid having a molecular
weight in the range of from 800 to 200,000, preferably 1000 to
150,000, especially 2,000 to 100,000; and
(j) balance water, preferably from 30 to 75%, more
preferably from 35 to 65%; and wherein at least 95 weight % of
the water is tightly bound to the crosslinked polyacrylic acid
thickening agent. 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.
The compositions will be supplied to the consumer in
suitable dispenser containers preferably formed of molded
plastic, especially polyolefin plastic, and most preferably
opaque or translucent polyethylene, for which the invention
compositions appear to have particularly favorable slip
characteristics. 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 li~uid and solid
viscoelastic gel, depending, for example, on the amount of the
polymeric thickener. The invention compositions can be
readily poured 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
2 ~
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 know 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
fill or partially fill the automatic dispenser cup of the
particular machine being used.
The invention also provides a method for c~eaning
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 the 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 from 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 amounts and proportions referred to herein are
by weight of the composition unless otherwise indicated.
34
Exam~le 1- The ~ollowing Eormulations A-F were prepared as ~c~)b~
ow:
Table 1
r - ~ _ ~
YORM~LATION ~
I TNGREDIENT A B C D E F
¦ Water Q.A Q.A Q.A Q.A Q.A Q.A _
arbopol 941 0.9 _ _ ¦ _
Carbopol 940 _ 0.9 _ _ _
Carbopol 614 _ 0.9 0.9 0.9 ¦ 0.9
NaOH ~50%) 2.4 4,5 4.5 4.0 4.5 4.5
Na-Silicate (47.5%)(1:2.4) 21 21 20.83 20.83 20.83 20.83
I
TKPP 15 15 _ _ _ _
KTPP _ _ 20.35 20.35 13 20.35
NaTPP (anhydrous) 13 13 5.26 5.26 3 5.26
DOWFAX3B2 1 0.8 0.8 n.8 0.8 0.8
LPKN (anti-foaming agent) 0.16 0.16 0.16 0.16 0.16 0 16
Fatty acid 0. loZ O, 201 0.15~ 0.15 o,l52 ! l57
Bleach (13.l%) 8.1 11.1 10.13 10.13 10.13 10.13
Grapthol green _ 0.0025 0.003 0.003 0.003 0.003 _
CI Direct Yellow 28 _ _ _ _ _ 0.003
Air (Vol. %) approx. ~ 2 2 2 2 2
Acrysol LMW 45-N (45.0%) _ _ _ _ 4.4 _
Highlights (fragrance) _ _ 0.05 0.05 0.05 0.05
K/Na 0.98 0.98 1.61 1.61 1.17 1.61
Density 1.35 1.37 1.37 1.37 1.28 1.37
Stability ambient 8 wks 8 wks 24 wks 24 wks 12 wks 4 wks
_
Stability 100F 2 wkæ 2 wks _ 20 wks 8 wks 4 wks
Stabiiity 120C?F _ _ _ 8 wks 8 wks 4 wks
Stability 140F _ _ _ 2 wks 2 wks 2 wks
Crystal growth (100"F) Yes Yes No No No No
Rheogram Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig 5 Fig 6
2 Stearic acid
Syncrowax C24_26
3 Syncrowax Cl 8 - 3 ~
2~ 3
Formulations A, B, C, D, E and F are prepared by first
forming a uniform dispersion 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 using a mixer equipped with a premier
blade, with agitation set at a medium shear rate, as
recommended by the manufacturer. After mixing for about 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
(about 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 is 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 remaining 3% of water and heating the
resulting mixture to a temperature in the range of 160F
(71C). In formulation E, the Acrysol LMW 45-N may be added
at this stage.
36
2 ~ 3 ~
The rheograms Eor the formulations A, B, C, D, E and F
are shown in figures 1-6, respectively.
These rheograms are obtained with the System 4 Rheometer
from Rheometrics equipped 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 exhibit
linear viscoelasticity as seen from the rheograms of figure 2-
6. No phase separation at from ambient temperature to 140F
were observed for any of the formulations for at least the
lS minimum number of weeks required 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 lOO~F, 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
previously 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 about 1 week at ambient temperature in a standard
32 ounce small necked polyethylene bottle. An amount of
2 ~ 3 ~
product 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 minutcs is repeated until no
more product flows from the bottle. At this time, the weight
of the bottle is measured. Bottle residue is calculated as
Wf x 100
Wo
Wo is the initial weight of the fiiled bottle and Wf is the
final weight of the filled bottle. The bottle residue for
each formulation A-F is about 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 Erom the
polyethylene bottle.
ExamPle 2
A Carbopol 614 slurry is formed as described in Example 1
except that the coloring agent is first added to the deionized
water (about 92% oE the total added water) and the amounts of
the ingredients are changed as shown below. The premix
(surfactant emulsion) of the surface active ingredients is
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
614 slurry in the following order: alkali metal silicate,
NaTPP (powder), KTPP (powder), surfactant emulsion~ bleach and
38
2 ~ 3 ~
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 l.00
NaOH (38% NazO) 6.38
Na silicate (1:24)(47.S%) 20.83
KTPP (anhydrous) powder 20.35
NaTPP (3O 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 (sp.
gr.) of 1.39 + 0.03. The viscosity at 80F measured with a
Brookfield 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.
39
2 ~ t'.;~ .~
Example 3
The following formulas were prepared according to the
- procedure of Example 1 and tested.
Table II
Ingredient Amount (wt. %)
Color Graphtol Green .003
Water Distilled 40.947
Carbopol 614 1.0
Na silicate (47.5%~ 20.83
NaOH 4.50
NaTPP 2.00
LPKN - 158 0.10
Stearic Acid 0.08
Isostearic Acid 0.03
Fragrance 0.03
Bleach (13%) 10.13
Stability 3 monthsStable No Sedimination
Brookfield Viscosity
At R.T. Spindle #64
1. # rpms 15,600 cps
2. 30 rpms 3,340 cps
Thixotropic Index 4.19
