Note: Descriptions are shown in the official language in which they were submitted.
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2301-1308
This invention relates to liquid laundry detergent composition.
Liquid non aqueous heavy duty laundry detergent compositions are
well known in the art. For instance, compositions of that type may
comprise a liquid non ionic surfactant in which are dispersed particles
of a builder, such as a polyphosphate builder, as shown for instance in
United States patents Nos. 4,316,812; 3,630,929; 4,264,466, and British
patents Nos. 1,205,711 and 1,270,040.
It is known that such suspensions can be stabilized against
settling by adding an inorganic insoluble thickening agent or dispersant
of very high surface area such as finely divided silica of extremely
fine particle size (e.g. of 5-100 millimicrons diameter such as sold
under the name Aerosol) or the other highly voluminous inorganic
carrier materials disclosed in United States Patent 3,630,929, or by
including various clays, such as attapulgite, as disclosed in United
States Patent 4,264,466. Grinding to very fine particle sizes also
increases the stability.
In accordance with one aspect of the invention, there is
provided a liquid heavy duty laundry detergent composition comprising
a suspension of an alkali metal polyphosphate builder salt in a liquid
non ionic surfactant said composition containing an organic phosphorus
compound having an acidic -POX group which compound is present in
effective amount to raise the yield value of said composition.
Thus, the stability of the suspension is increased by including
therein an acidic organic phosphorus compound having an acidic - POW
group. This may be, for instance, a partial ester of phosphoric acid and
an alcohol such as an alkanol which has a lipophilic character, having,
for instance, more than 5 carbon atoms, e.g. 8 to 20 carbon atoms. It is
found that as a result of the inclusion of quite small amounts of the
acidic organic phosphorus compound the suspension becomes significantly more
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stable against settling on standing but remains parboil Thus,
as shown below, inclusion of the acidic phosphorus compound in-
creases the yield value of the suspension, but decreases its
plastic viscosity.
It 15 believed that the use of the acidic phosphorus
compound may result in the formation of a high energy physical
bond between the -POX portion of the molecule and the surfaces
of the inorganic polyphosphate builder so that these surfaces
take on an organic character and become more compatible with the
non ionic surfactant.
The invention is particularly suitable for use with
suspensions in which the particle size of the polyphosphate build-
or is reduced tub below about lo microns.
The suspensions of the polyphosphate builder, such
as sodium tripolyphosphate ("TOP") in the non ionic surfactant
are found to behave, theologically, substantially according to
the Caisson equation:
l/2 l/2 l/2 ' 112
+
is the shear rate, is the shear stress, is the yield
stress (or yield value) and CO is the infinite shear rate
plastic viscosity (which can be measured by determining the
slope of the graph of the square root of the shear stress (as
ordinate) vs. the square root of the shear rate. The yield
value is the minimum shear stress below which no flow occurs
(i.e., it corresponds to the intercept at the ordinate, at zero
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shear rate, of the graph mentioned above). it is accordingly
a criterion of stability. The plastic v16cosity is a measure
of the flyability once the yield value has been overcome.
It is preferred that the yield value (measured at
25 C) be at least about 2 Pixels and (for pour ability and disk
pens ability) not above about 8 Pascal, such as about 3 to 7
Pascal, more preferably about 4 Pascal.
For studying thus theological behavior, one should
use a uniform, well defined shear rat viscometer (with either
coaxial cylinders or cone-plate geometry) such as a ~heometrics
remoter.
The suspensions are preferably prepared by grinding
a mixture of non ionic surfactant, particles of polyphosphate
builder salt and the acidic organic phosphorus compound in a
mill which will break down the builds particles to diameters
below about 10 microns. The builder salt will generally be sup-
plied as much larger particles of above about 40 microns die- -
meter, such as lo, 200 or 400 microns. If desired, the builder
salt may be premixed with the acidic organic phosphorus come
pound (e.g. by spraying the acidic compound, dispersed or disk
solved in water or volatile organic solvent, onto the builder
salt).
During grinding it is preferred that the proportion of
solid ingredients be high enough (e.g. at least about 40% such
as about SWISS that the solid particles are in contact with each
other and are not substantially shielded Jo m one another by the
non ionic surfactant liquid. Mills which employ grinding balls
(ball mills or similar mobile grinding elements have given
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good results. Thus, one may use a laboratory batch attritor
having 8 mm diameter statute grinding balls. For larger scale
work a continuously operating mill in which there are 1 mm or
1.5 em diameter grinding balls working in a very small gap
between a stators and a rotor operating at a relatively high
speed (e.g. a Cobalt mill) may be employed; when using such
a mill it is desirable to pass the blend of non ionic surfactant
and solids first through a mill which does not effect such fine
grinding (e.g., a killed mill) to reduce the particle size to
less than 100 microns (e.g. to about 40 microns), prior to the
step of grinding to an average particle diameter below 10
microns in the continuous ball mill.
The following Example is given to illustrate this
invention further:
EXAMPLE
A non aqueous heavy duty built liquid detergent come
position is prepared by blending non ionic surfactant and sodium
tripolyphosphate ("TOP") with other ingredients with and without
an acidic organic phosphorus compound, as described below, and
then grinding the blend in an attritor mill (to reduce the particle
size of the suspended ingredients to less than 10 microns). The
grinding conditions are identical in each case: grinding for
hour in an attritor mill containing 8 mm diameter statute
grinding balls. (Wieneroto*W-l.S attritor, charged with 2.5Kg
of mixture).
* Trade Mark
OOZE
A B C D
Proportion of acidic organic
phosphorus compound (%) 0 0.1 0.2 0.3
Yield stress (Pascal) 0.3 1.6 3.2 5.6
Plastic viscosity (Pascal seconds) 1.1 1.0 1.0 0.9
The apparent viscosity at any shear rate can be
calculated, using the Caisson equation and the relationship:
apparent viscosity equals shear stress divided by shear rate.
The acidic organic phosphorus compound in this En-
ample is a partial ester of phosphoric acid and a C16 to C18
alkanol (Empiphos 5632 from Martian); it is made up of about
35% monster and 65% divester.
The composition contains the following ingredients
in the proportions specified.
35% non ionic surfactant comprising a mixture of equal
parts of;
(a) a relatively water soluble non ionic ~urfactant
which forms a gel when mixed with water at 25 C specifically a
C13 to C15 alkanol which has been alkoxylated to introduce 10
ethylene oxide and S propylene oxide units per alkanol unit and
(b) a less water-soluble non ionic surfactant specie
focally a C13 to C15 alkanol which has been alkoxylated to into-
dupe 4 ethylene oxide and 7 propylene oxide units per alkanol
unit.
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12% of the reaction product prepared by mixing 100 g
of succinic android with 522 go of the non ionic surfactant
known as Dobanol 25-7 (the product of wthoxylation of a C12 to
C15 alkanol, which product has about 7 ethylene oxide units per
molecule of alkanol) and 0.1 g. of pardon (which acts so an
esterification catalyst here); heating at 60C for 2 hours,;
cooling and filtering to remove unrequited succinic material
(infrared analysis indicates that substantially all the free
hydroxyls of the surfactant have reacted to form an acidic half
ester in which the OH group of the non ionic surfactant has been
esterified with one carboxyl group of the succinic android).
31~5% TOP in formulation A; owe in formulation B;
31.3% in C and 31~ 2% in D.
9% sodium perorate MindWrite, Nub H20.
4 5% tetraacetyl ethylene Damon; this is an activator
for the sodium perorate
4% copolymer of about equal-moles of methacrylic acid
and malefic android, completely neutralized to form the sodium
salt thief (Cyclone CP5); this serves to inhibit incrustation
(as from formation of dicalcium phosphate).
1% diethylene Damon pentamethylene phosphoric acid
sodium salt; this is a sequestering agent agent having a high
stability constant for complexation.
1% proteolytic enzyme slurry (it non ionic surfactant)
(Espresso)
1% mix of pa carboxymethylcellulose and hydroxymethyl-
cellulose (an antiredepoition agent) (Ralston DO 4050)
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0.5% perfume
0.5~ optical brightener of silbene 4 type)
The TOP preferably is largely aiders material
containing a small amount of TOP hexahydrate (e.g. an amount
such that the chemically bound water content is about 3%,
which corresponds to about one H20 per pentasodium Tripoli-
phosphate molecule). Such TOP may be produced by treating
an hydrous TOP with a limited amount of water. The presence of
the hexahydrate slows down the rapid rate of solution of the
TOP in the wash bath and inhibits caking. One suitable grade
of TOP is sold under the name Thermphos NW; the particle size
of this TOP as supplied is in the neighborhood of 400 microns,
it phase I content it about 60%.
The mixture dispenses readily with cold water in the
automatic washing machine. Its specific gravity is about 1.25
and it gives excellent washing when used at a dosage of about
lo grams per wash load (as compared with 170 grams per wash
lid Son the usual heavy duty laundry detergent powders) in
conventional European home laundry machines (which employ about
20 liters of water for the washing bath.
The partial esters of phosphoric acid are known to
act as foam suppressants and are mentioned for that purpose in
US. patent 4,264,466 (Column 33, lines 34-45). The compositions
of this Example are, however, of the low-foaming type; when used
to wash conventional wash loads in typical European e.g., Germ
man front-loading washing machines. They exhibit little foam
even in the absence of the partial ester of phosphoric acid and
thus do not require any foam suppressant.
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The acidic organic phosphorus compound may be sol-
acted from a wide variety of materials, in addition to the
partial esters of phosphoric acid and alkanols mentioned above.
Thus, one may employ a partial ester of phosphoric or phosphorous
acid with a moo or polyhydric alcohol such as hexylene glycol,
ethylene glycol, dip or t'ri-ethylene glycol or higher polyethylene
glycol, polypropylene glycol, glycerol, sorbitol, moo or dip
glycerides of fatty acids, etc. in which one, two or more of
the alcoholic I groups of the molecule may be esterified with
the phosphorus acid. The alcohol may be a non ionic surfactant
such as an ethoxylated or ethoxylated-propoxylated higher alkanol,
higher alkyd phenol, or higher alkyd aside. The -POX group need
not be bonded to the organic portion of the molecule through an
ester linkage; instead it may be directly bonded to carbon (as
in a phosphoric acid, such as a polystyrene in which some of
the aromatic rings carry phosphoric acid or phosphinic acid
groups, or an alkylphosphonic acid, such as propel or laurel-
phosphoric acid) or may be connected to the carbon through other
intervening linkages such as linkages through 0, S or N atoms).
Preferably, the carbon phosphorus atomic ratio in the organic
phosphorus compound is at least 3:1, such as 5:1, 10:1, 20:1,
30:1 or 40:1. Among the suitable compounds are the Phosphate
ester surfactants described and listed in Kirk-Othmer "Encyclo-
podia of Chemical Technology 3rd Edition, Vol. 22 (1983) Pages
359 to 361.
The particular partial alkyd ester of phosphoric acid
and the C16 to C18 alkanol, described in the foregoing Example,
is a solid which generally swells, but does not dissolve in the
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non ionic surf act ant. It is supplied US a powder. In a pro-
furred method, used in that example, the TOP is added last
(after the other solid ingredients have been added to the fig-
rid blend of non ionic surfactant and reaction product of sue-
cynic android and non ionic surfactant) and the powder of
partial alkyd ester of phosphoric acid is added just before
the TOP. Acidic organic phosphorus compounds soluble in the
non ionic surfactant may also be employed.
As is well known, the non ionic surfactants are char-
acterized by the presence of an organic hydrophobic group and
an organic hydrophilic group and are typically produced by the
condensation of an organic alpha tic or alkyd aromatic hydra-
phobic compound with ethylene oxide (hydrophilic in nature).
Practically any hydrophobic compound having a car boxy, hydra,
amino or amino group with a free hydrogen attached to the
nitrogen can be condensed with ethylene oxide or with the polyp
hydration product thereof, polyethylene glycol, to form a non-
ionic detergent. The length of the hydrophilic or polyoxy-
ethylene chain can be readily adjusted to achieve the desired
balance between the hydrophobic and hydrophilic groups. Typical
suitable non ionic surfactants are those disclosed in US. pat-
ens 4,316,812 and 3,630,929, as well as those described and
listed in the discussion of non ionic surfactants in Kirk-Othmer
"Encyclopedia of Chemical Technology", 3rd Edition, Vol. 22 (1983),
Pages 360 to 379.
Non ionic surfactants often tend to form gels with limited
amounts of cold water; this can sometimes interfere with the
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complete dispensing of the composition from the usual dispenser
found in conventional automatic home laundry machines used on
Europe. To lower the golfing temperature, and thus promote
easier dispensing, there may be included in the composition a
carboxylic acid anti-gelling agent. A preferred type of agent
of this type is a compound having a carboxy~ic moiety joined
to the residue of a non ionic surfactant, e.g., a half ester of
succinic acid or other dicarboxylic acid in which the Ox group
of the non~onic surfactant has been esterified with one carboxyl
group of the acid. This material is preferably in solution in
non ionic surfactant.
The polyphosphate builder salt is preferably an alkali
metal (e.g. pa or K) tripolyphosphate, pyrophosphate ego. twitter-
sodium pyrophosphate) or hexamethaphosphate. It is preferred
that these be largely in an hydrous form. Mixtures ox two or more
different polyphosphates may be used. The polyphosphate may also
be used in admixture with one or more other water-soluble deter-
gent builders.
Among the suitable builders are inorganic and organic
builder salts such as the phosphates, carbonates, silicates,
phosphonates, polyhydroxysulfonates, polycarboxylates and the
like. Typical suitable builders are those disclosed in US. pat-
ens 4,316,812; 4,264,466; and 3,630,929.
Since, as indicated in the Example, the compositions
of this invention may be used at relatively low dosage, it is
desirable to supplement any phosphate or phosphate-forming
builder (such as sodium tripolyphosphate) with an auxiliary
builder such as polymeric carboxylic acid having high calcium
binding capacity, in amount in the range, for instance, of about
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1 to 10% of the composition, to inhibit incrustation which
could otherwise be caused by formation of an insoluble calcium
phosphate. Such auxiliary builders are well known in the art.
The composition preferably comprises a per oxygen
bleaching agent. This may be a per oxygen compound, such as an
alkali metal perorate, per carbonate or per phosphate; a portico-
laxly suitable material is sodium perorate MindWrite. The per-
oxygen compound is preferably used in admixture with an activator
therefore Suitable activators are those disclosed in So pat-
en 4,264,466 or in column 1 of US. patent 4,430,244. Polyp
assaulted compounds are preferred activators; among these, come
pounds such as tetraacetyl ethylene Damon ("TOED") and glucose
pentaacetate are particularly preferred.
The activator usually interacts with the per oxygen
compound to form a peroxyacid bleaching agent in the wash water.
It is preferred to include a sequestering agent of high completing
power to inhibit any undesired reaction between such peroxyacid
and hydrogen peroxide in the wash solution in the presence of
metal ions. Such a sequestering agent is an organic compound
which is able to form a complex with Queue ions, such that the
stability constant (pi) of the complexation it equal to or great-
or than 6, at 25C, in water of an ionic strength of Do milliliter,
pry being conventionally defined by the formula: pK=-log K where
R represent the equilibrium constant. Thus, for example, the pox
values for complexation of copper ion with ETA and ETA at the
stated conditions are 12.7 and 18.8, respectively. Suitable so-
questering agents include the sodium salts of nitrilotriacetic
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-SWISS
acid (NAT); ethylene Damon tetraacetic acid (ETA); diethylene
trillion pentaacetic acid (DETPA); diethylene thiamine pent-
ethylene phosphoric acid DUMP and ethylene diamlne twitter-
ethylene phosphoric acid (EDITEMPA).
Other ingredients which may be included in the come
position are enzymes (e.g. pro teases, amylases or lapses or
mixtures thereof), optical brighteners, anti redeposition agents,
colorants (e.g. pigments or dyes) etc.
The composition may also contain an inorganic insole
ruble thickening agent or dispersant ox very high surface area
such as finely divided silica of extremely fine particle size
(e.g. of 5-100 millimicrons diameter such as sold under the
name Aerosol) or the other highly voluminous inorganic carrier
materials disclosed in US. patent 3,630,929, in proportions of
0.1-10%, e.g. 1 to 5%. For best results it is preferable, how-
ever, that compositions which form peroxyacids in the wash bath
(e.g. compositions containing per oxygen compound and activator
therefore be substantially free of such compounds and of other
silicates; it has been found, for instance, that silica and
silicates promote the undesired decomposition of the peroxyacid.
In addition, the use of these water-~nsoluble inorganic materials
can present other problems in the system. No voluminous silica
or chain structure type clay is needed in the practice of this
invention sod the composition is preferably substantially free
of such materials.
* Trade Mark
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While in the preferred compositions the average part-
tale size of the solids has been reduced to less than about
10 microns (e.g., typically only about 5-10% of the solids con-
tent has a particle size above lo microns), the invention may
also be applied to compositions which have not been so finely
ground. It will be understood thaw finer grinding increases
the stability of the composition against settling on standing;
according to Stokes law the smaller the particle size the lower
the rate of sedimentation. By raising the yield value obtained
with a given degree of grinding, the use of the acidic pros-
chorus compound can make it possible to increase the stability
of compositions in which the average particle diameter is say
15, 20, or 25 microns, as by using increased amounts of the
acidic phosphorus compound to attain the desired yield value of
at least about 2 Pascal.
In the compositions of the invention, typical propriety-
ions of the ingredients are as follows:
Suspended detergent builder, within the range of
about 10 to 60%, such as 20 to 50%, e.g., about 25 to 40%;
Liquid phase comprising non ionic surfactant (and, option-
ally, dissolved carboxylic acid gel-inhibitor) within the range
of about 30 to 70%, such as about 40 to 60%; this phase may also
include a delineate such as a glycol, e.g.. polyethylene glycol
ego., "PEG 400") or hexylene glycol.
; Carboxylic acid antigelling agent, an amount to supply
in the range of about 0.5 to 10 parts (e.g., about 1 to 6 parts,
such as about 2 to 5 parts) of -COO (M.~.45) per 100 parts of
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the blend o f such compound and the non ionic surfactant; typical-
lye the amount of this anti-gelling agent is in the range of
about 0.01 to 1 part per part of non ionic surfactant, such as
about 0.05 to 0.6 part, e.g. about 0.2 to 0.5 part;
Per oxygen compound (such as sodium perorate moo-
hydrate) in the range of about 2 to 15%, such as about 4 to lo;
Activator, in the Lange of about 1 to I such as
about 3 to 6%;
Sequestering agent of high co~plexing power, in the
singe of about to 3%, such as about to 2%;
Acidic organic -POX compound, in the range of Oily
to 5%, such as about 0.05 to 2%, e.g., about 0.1 to 1%.
In this application all proportions are by weight us-
less otherwise indicated. In the Examples atmospheric pressure
is used unless otherwise indicated.
It is understood that the foregoing detailed de-
ascription is merely by way of illustration and that variations
may be made therein without departing from the spurt of the in-
mention.
