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Description  |
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BACKGROUND OF THE INVENTION
(1) Field of Invention
This invention relates to stabilization of non-aqueous liquid suspensions,
especially non-aqueous liquid fabric-treating compositions. More
particularly, this invention relates to non-aqueous liquid laundry
detergent compositions which are made stable against phase separation
under both static and dynamic conditions and are easily pourable, to the
method of preparing these compositions and to the use of these
compositions for cleaning soiled fabrics.
(2) Discussion of Prior Art
Liquid nonaqueous heavy duty laundry detergent compositions are well known
in the art. For instance, compositions of this type may comprise a liquid
nonionic surfactant in which are dispersed particles of a builder, as
shown for instance in U.S. Pat. Nos. 4,316,812; 3,630,929; 4,254,466; and
4,661,280.
Liquid detergents are often considered to be more convenient to employ than
dry powdered or particulate products and, therefore, have found
substantial favor with consumers. They are readily measurable, speedily
dissolved in the wash water, capable of being easily applied in
concentrated solutions or dispersions to soiled areas on garments to be
laundered and are non-dusting, and they usually occupy less storage space.
Additionally, the liquid detergents may have incorporated in their
formulations materials which could not stand drying operations without
deterioration, which materials are often desirably employed in the
manufacture of particulate detergent products.
Although they are possessed of many advantages over unitary or particulate
solid products, liquid detergents often have certain inherent
disadvantages too, which have to be overcome to produce acceptable
commercial detergent products. Thus, some such products separate out on
storage and others separate out on cooling and are not readily
redispersed. In some cases the product viscosity changes and it becomes
either too thick to pour or so thin as to appear watery. Some clear
products become cloudy and others gel on standing.
The present inventors have been extensively involved as part of an overall
corporate research effort in studying the rheological behavior of nonionic
liquid surfactant systems with particulate matter suspended therein. Of
particular interest have been non-aqueous, built, liquid laundry detergent
compositions and the problems of phase separation and settling of the
suspended builder and other laundry additives. These considerations have
an impact on, for example, product pourability, dispersibility and
stability.
It is known that one of the major problems with built, liquid laundry
detergents is their physical stability. This problem stems from the fact
that the density of the solid suspended particles is higher than the
density of the liquid matrix. Therefore, the particles tend to sediment
according to Stoke's law. Two basic solutions exist to solve the
sedimentation problem: increasing liquid matrix viscosity and/or reducing
solid particle size.
For instance, it is known that such suspensions can be stabilized against
settling by adding inorganic or organic thickening agents or dispersants,
such as, for example, very high surface area inorganic materials, e.g.
finely divided silica, clays, etc., organic thickeners, such as the
cellulose ethers, acrylic and acrylamide polymers, polyelectrolytes, etc.
However, such increases in suspension viscosity are naturally limited by
the requirement that the liquid suspension be readily pourable and
flowable, even at low temperature. Furthermore, these additives do not
contribute to the cleaning performance of the formulation. U.S. Pat. No.
4,661,280 to T. Ouhadi, et al. discloses the use of aluminum stearate for
increasing stability of suspensions of builder salts in liquid nonionic
surfactant. The addition of small amounts of aluminum stearate increases
yield stress without increasing plastic viscosity.
According to U.S. Pat. No. 3,985,668 to W. L. Hartman, an aqueous false
body fluid abrasive scouring composition is prepared from an aqueous
liquid and an appropriate colloid-forming material, such as clay or other
inorganic or organic thickening or suspending agent, especially smectite
clays, and a relatively light, water-insoluble particulate filler
material, which, like the abrasive material, is suspended throughout the
false body fluid phase. The lightweight filler has particle size diameters
ranging from 1 to 250 microns and a specific gravity less than that of the
false body fluid phase. It is suggested by Hartman that inclusion of the
relatively light, insoluble filler in the false body fluid phase helps to
minimize phase separation, i.e. minimize formation of a clear liquid layer
above the false body abrasive composition, first, by virtue of its
buoyancy exerting an upward force on the structure of the colloid-forming
agent in the false body phase counteracting the tendency of the heavy
abrasive to compress the false body structure and squeeze out liquid.
Second, the filler material acts as a bulking agent replacing a portion of
the water which would normally be used in the absence of the filler
material, thereby resulting in less aqueous liquid available to cause
clear layer formation and separation.
British Application GB 2,168,377A, published June 18, 1986, discloses
aqueous liquid dishwashing detergent compositions with abrasive, colloidal
clay thickener and low density particulate filler having particle sizes
ranging from about 1 to about 250 microns and densities ranging from about
0.01 to about 0.5 g/cc, used at a level of from about 0.07% to about 1% by
weight of the composition. It is suggested that the filler material
improves stability by lowering the specific gravity of the clay mass so
that it floats in the liquid phase of the composition. The type and amount
of filler is selected such that the specific gravity of the final
composition is adjusted to match that of the clear fluid (i.e. the
composition without clay or abrasive materials). According to this patent
the filler material improves stability by lowering the specific gravity of
the clay mass so that it floats in the aqueous liquid phase.
It is also known to include 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 Aerosil) or the other highly voluminous inorganic
carrier materials as disclosed in U.S. Pat. No. 3,630,929.
It has long been known that aqueous swelling colloidal clays, such as
bentonite and montmorillonite clays, can be modified by exchange of the
metallic cation groups with organic groups, thereby changing the
hydrophilic clays to organophilic clays. The use of such organophilic
clays as gel-forming clays has been described in U.S. Pat. 2,531,427 to E.
A. Hauser. Improvements and modifications of the organophilic gel-forming
clays are described, for example, in the following U.S. Pat. Nos. No.
2,966,506 - Jordan; 4,105,578 - Finlayson, et al.; 4,208,218 Finlayson;
4,287,086 - Finlayson; 4,434,075 - Mardis, et al.; 4,434,076 - Mardis, et
al.; all assigned to NL Industries, Inc., formerly National Lead Company.
According to these NL patents, these organophilic clay gellants are useful
in lubricating greases, oil based muds, oil base packer fluids, paints,
paint-varnish-lacquer removers, adhesives, sealants, inks, polyester gel
coats and the like. However, use as a stabilizer in a non-aqueous liquid
detergent composition for laundering fabrics has not been suggested.
On the other hand, the use of clays in combination with quaternary ammonium
compounds (often referred to as "QA" compounds) to impart fabric softening
benefits to laundering compositions has been described.. For instance,
mention can be made of the British Patent Application GB 2,141,152 A,
published Dec. 12, 1984, to P. Ramachandran, and the many patents referred
to therein for fabric softening compositions based on organophilic QA
clays.
According to the aforementioned U.S. Pat. No. 4,264,466 to Carleton, et
al., the physical stability of a dispersion of particulate materials, such
as detergent builders, in a non-aqueous liquid phase is improved by using
as a primary suspending agent an impalpable chain structure type clay,
including sepiolite, attapulgite, and palygorskite clays. The patentees
state and the comparative examples in this patent show that other types of
clays, such as montmorillonite clay, e.g. Bentolite L, hectorite clay
(e.g. Veegum T) and kaolinite clay (e.g., Hydrite PX), even when used in
conjunction with an auxiliary suspension aid, including cationic
surfactants, inclusive of QA compounds, are only poor suspending agents.
Carleton, et al. also refer to use of other clays as suspension aids and
mention, as examples, U.S. Pat. Nos. 4,049,034 and 4,005,027 (both aqueous
systems); and U.S. Pats. 4,166,039; 3,259,574; 3,557,037 and 3,549,542;
and U.K. Patent Application No. 2,017,072.
Commonly assigned copending application Ser. No. 063,199, filed June 12,
1987 (Atty's Docket IR-347LG) discloses incorporation into non-aqueous
liquid fabric treating compositions of up to about 1% by weight of an
organophilic water-swellable smectite clay modified with a cationic
nitrogen-containing compound including at least one long chain hydrocarbon
having from about 8 to about 22 carbon atoms to form an elastic network or
structure throughout the suspension to increase the yield stress and
increase stability of the suspension.
While the addition of the organophilic clay improves stability of the
suspension, still further improvements are desired, especially for
particulate suspensions having relatively low yield values for optimizing
dispensing and dispersion during use.
Grinding to reduce the particle size as a means to increase product
stability provides the following advantages:
(1) the particle specific surface area is increased, and, therefore,
particle wetting by the non-aqueous vehicle (liquid non-ionic) is
proportionately improved; and
(2) the average distance between pigment particles is reduced with a
proportionate increase in particle-to-particle interaction.
Each of these effects contributes to increase the rest-gel strength and the
suspension yield stress while at the same time,, grinding significantly
reduces plastic viscosity.
The above-mentioned U.S. Pat. No. 4,316,812 discloses the benefits of
grinding solid particles, e.g., builder and bleach, to an average particle
diameter of less than 10 microns. However, it has been found that merely
grinding to such small particle sizes does not, by itself, impart
sufficient long term stability against phase separation.
In the commonly assigned copending application filed on July 15, 1987 in
the names of N. Dixit, et al. under Ser. No. 073,653 (Attorney's Docket
IR-4494), and titled "STABLE NON-AQUEOUS CLEANING COMPOSITION CONTAINING
LOW DENSITY FILLER AND METHOD OF USE" the use of low density filler
material for stabilizing suspensions of finely divided solid particulate
matter in a liquid phase against phase separation by equalizing the
densities of the dispersed particle phase and the liquid phase is
disclosed. These modified liquid suspensions exhibit excellent phase
stabilization when left to stand for extended periods of time, e.g., up to
6 months or longer or even when subjected to moderate shaking. However, it
has recently been observed that when the low-density filler modified
suspensions are subjected to strong vibrations, such as may be encountered
during transportation by rail, truck, etc., the homogeneity of the
dispersion is degraded as a portion of the low density filler migrates to
the upper surface of the liquid suspension.
In commonly assigned, copending application Ser. No. 073,551, filed July
15, 1987 in the name of Cao et al. (Attorney's Docket No. IR-344LG)
entitled "Stable Non-Aqueous Suspension Containing Organophilic Clay And
Low Density Filler" the use of low density filler material for
stabilizing suspensions of finely divided solid particulate matter in a
liquid phase against phase separation is disclosed as being improved by
the incorporation of organophilic modified clays which aid in resisting
the destabilizing effect of strong vibrations.
Nonetheless, still further improvements are desired in the stability of
non-aqueous liquid fabric treating compositions.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide liquid fabric
treating compositions which are suspensions of insoluble fabric-treating
particles in a non-aqueous liquid and which are storage and transportation
stable, easily pourable and dispersible in cold, warm or hot water.
Another object of this invention is to formulate highly built heavy duty
non-aqueous liquid nonionic surfactant laundry detergent compositions
which resist settling of the suspended solid particles or separation of
the liquid phase.
A more general object of the invention is to provide a method for improving
the stability of suspensions of finely divided solid particulate matter in
a non-aqueous liquid matrix by incorporating a low density filler and/or a
vicinal hydroxy compound into the suspension whereby phase separation of
the composition is inhibited.
These and other objects of the invention which will become more apparent
hereinafter have been accomplished based on the inventors' discovery that
by adding a small amount of a stabilizer, having the formula
##STR1##
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4, independently, represent H,
lower alkyl of up to 6 carbon atoms, hydroxy-substituted lower alkyl of up
to 6 carbon atoms, or aryl and R.sup.1 and R.sup.4, together with the
carbon atoms to which they are attached, may form a 5- or 6-membered
carbocyclic ring, with the proviso that no more than two of R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 may be aryl, to a liquid suspension of at
least one particulate detergent builder salt in at least one nonionic
surfactant, phase separation of the suspension may be inhibited.
According to another aspect, the invention provides a method for cleaning
soiled fabrics by contacting the soiled fabric with the liquid non-ionic
laundry detergent composition as described above.
According to still another aspect of the invention, a method is provided
for stabilizing a suspension of a first finely divided particulate solid
substance in a continuous liquid vehicle phase, the suspended solid
particles having a density greater than the density of the liquid phase,
which method involves adding to the suspension of solid particles an
amount of a low density filler such that the density of the dispersed
solid particles together with the low density filler becomes similar to
the density of the liquid phase and a small amount of the aforementioned
stabilizer to inhibit phase separation of the suspension.
In the preferred embodiment of special interest herein the liquid phase of
the composition of this invention is comprised predominantly or totally of
liquid nonionic synthetic organic detergent. A portion of the liquid phase
may be composed, however, of organic solvents which may enter the
composition as solvent vehicles or carriers for one or more of the solid
particulate ingredients, such as in enzyme slurries, perfumes, and the
like. Also as will be described in detail below, organic solvents, such as
alcohols and ethers, may be added as viscosity control and anti-gelling
agents.
DETAILED DESCRIPTION OF THE INVENTION
The nonionic synthetic organic detergents employed in the practice of the
invention may be any of a wide variety of such compounds, which are well
known and, for example, are described at length in the text Surface Active
Agents, Vol. II, by Schwartz, Perry and Berch, published in 1958 by
Interscience Publishers, and in McCutcheon's Detergents and Emulsifiers,
1969 Annual, the relevant disclosures of which are hereby incorporated by
reference. Usually, the nonionic detergents are poly-lower alkoxylated
lipophiles wherein the desired hydrophile-lipophile balance is obtained
from addition of a hydrophilic poly-lower alkoxy group to a lipophilic
moiety. A preferred class of the nonionic detergent employed is the
poly-lower alkoxylated higher alkanol wherein the alkanol is of 10 to 22
carbon atoms and wherein the number of mols of lower alkylene oxide (of 2
or 3 carbon atoms) is from 3 to 20. Of such materials it is preferred to
employ those wherein the higher alkanol is a higher fatty alcohol of about
12 to 18 carbon atoms and which contain from 3 to 14, preferably 3 to 12
lower alkoxy groups per mol. The lower alkoxy is often just ethoxy but in
some instances, it may be desirably mixed with propoxy, the latter, if
present, often being in a minor (less than 50%) proportion. Exemplary of
such compounds are those wherein the alkanol is of 12 to 15 carbon atoms
and which contain about 7 ethylene oxide groups per mol, e.g., Neodol 25-7
and Neodol 23-6.5, which products are made by Shell Chemical Company, Inc.
The former is a condensation product of a mixture of higher fatty alcohols
averaging about 12 to 15 carbon atoms, with about 7 mols of ethylene oxide
and the latter is a corresponding mixture wherein the carbon atom content
of the higher fatty alcohol is 12 to 13 and the number of ethylene oxide
groups present averages about 6.5. The higher alcohols are primary
alkanols. Other examples of such detergents include Tergitol 15-S-7 and
Tergitol 15-S-9, both of which are linear secondary alcohol ethoxylates
made by Union Carbide Corp. The former is mixed ethoxylation product of 11
to 15 carbon atoms linear secondary alkanol with seven mols of ethylene
oxide and the latter is a similar product but with nine mols of ethylene
oxide being reacted.
Also useful in the present compositions as a component of the nonionic
detergent are higher molecular weight nonionics, such as Neodol 45-11,
which are similar ethylene oxide condensation products of higher fatty
alcohols, with the higher fatty alcohol being of 14 to 15 carbon atoms and
the number of ethylene oxide groups per mol being about 11. Such products
are also made by Shell Chemical Company. Another preferred class of useful
nonionics are represented by the commercially well known class of
nonionics which are the reaction product of a higher linear alcohol and a
mixture of ethylene and propylene oxides, containing a mixed chain of
ethylene oxide and propylene oxide, terminated by a hydroxyl group.
Examples include the nonionics sold under the Plurafac trademark of BASF,
such as Plurafac RA30, Plurafac RA40 (a C.sub.13 -C.sub.15 fatty alcohol
condensed with 7 moles propylene oxide and 4 moles ethylene oxide),
Plurafac D25 (a C.sub.13 -C.sub.15 fatty alcohol condensed with 5 moles
propylene oxide and 10 moles ethylene oxide), Plurafac B26, and Plurafac
RA50 (a mixture of equal parts Plurafac D25 and Plurafac RA40).
Generally, the mixed ethylene oxide-propylene oxide fatty alcohol
condensation products represented by the general formula
RO(C.sub.3 H.sub.6 O).sub.p (C.sub.2 H.sub.4 O).sub.q H,
wherein R is a straight or branched, primary or secondary aliphatic
hydrocarbon, preferably alkyl or alkenyl, especially preferably alkyl, of
from 6 to 20, preferably 10 to 18, especially preferably 12 to 18 carbon
atoms, p is a number of up to 14, preferably 3 to 8, and q is a number of
up to 14, preferably 3 to 12, can be advantageously used where low foaming
characteristics are desired. In addition, these surfactants have the
advantage of low gelling temperatures.
Another group of liquid nonionics are available from Shell Chemical
Company, Inc. under the Dobanol trademark: Dobanol 91-5 is an ethoxylated
C.sub.9 -C.sub.11 fatty alcohol with an average of 5 moles ethylene oxide;
Dobanol 25-7 is an ethoxylated C.sub.12 -C.sub.15 fatty alcohol with an
average of 7 moles ethylene oxide; etc.
In the preferred poly-lower alkoxylated higher alkanols, to obtain the best
balance of hydrophilic and lipophilic moieties the number of lower
alkoxies will usually be from 40% to 100% of the number of carbon atoms in
the higher alcohol, such as 40 to 60% thereof and the nonionic detergent
will often contain at least 50% of such preferred poly-lower alkoxy higher
alkanol.
Higher molecular weight alkanols and various other normally solid nonionic
detergents and surface active agents may be contributory to gelation of
the liquid detergent and consequently, will preferably be omitted or
limited in quantity in the present compositions, although minor
proportions thereof may be employed for their cleaning properties, etc.
With respect to both preferred and less preferred nonionic detergents the
alkyl groups present therein are generally linear although branching may
be tolerated, such as at a carbon next to or two carbons removed from the
terminal carbon of the straight chain and away from the alkoxy chain, if
such branched alkyl is not more than three carbons in length. Normally,
the proportion of carbon atoms in such a branched configuration will be
minor rarely exceeding 20% of the total carbon atom content of the alkyl.
Similarly although linear alkyls which are terminally joined to the
alkylene oxide chains are highly preferred and are considered to result in
the best combination of detergency, biodegradability and non-gelling
characteristics, medial or secondary joinder to the alkylene oxide in the
chain may occur. It is usually in only a minor proportion of such alkyls,
generally less than 20% but, as is the case of the mentioned Tergitols,
may be greater. Also, when propylene oxide is present in the lower
alkylene oxide chain, it will usually be less than 20% thereof and
preferably less than 10% thereof.
When greater proportions of non-terminally alkoxylated alkanols, propylene
oxide-containing poly-lower alkoxylated alkanols and less
hydrophile-lipophile balanced nonionic detergent than mentioned above are
employed and when other nonionic detergents are used instead of the
preferred nonionics recited herein, the product resulting may not have as
good detergency, stability, viscosity and non-gelling properties as the
preferred compositions but use of viscosity and gel controlling compounds
can also improve the properties of the detergents based on such nonionics.
In some cases, as when a higher molecular weight poly-lower alkoxylated
higher alkanol is employed, often for its detergency, the proportion
thereof will be regulated or limited in accordance with the results of
routine experiments, to obtain the desired detergency and still have the
product non-gelling and of desired viscosity. Also, it has been found that
it is only rarely necessary to utilize the higher molecular weight
nonionics for their detergent properties since the preferred nonionics
described herein are excellent detergents and additionally, permit the
attainment of the desired viscosity in the liquid detergent without
gelation at low temperatures. Mixtures of two or more of these liquid
nonionics can also be used and in some cases advantages can be obtained by
the use of such mixtures.
In view of their low gelling temperatures and low pour points, another
preferred class of nonionic surfactants includes the C.sub.12 -C.sub.13
secondary fatty alcohols with relatively narrow contents of ethylene oxide
in the range of from about 7 to 9 moles, especially about 8 moles ethylene
oxide per molecule and the C.sub.9 to C.sub.11, especially C.sub.10 fatty
alcohols ethoxylated with about 6 moles ethylene oxide.
Furthermore, in the compositions of this invention, it may be advantageous
to include an organic solvent or diluent which can function as a viscosity
control and gel-inhibiting agent for the liquid nonionic surface active
agents. Lower (C.sub.1 -C.sub.6) aliphatic alcohols and glycols, such as
ethanol, isopropanol, ethylene glycol, hexylene glycol and the like have
been used for this purpose. Polyethylene glycols, such as PEG 400, are
also useful diluents. Alkylene glycol ethers, such as the compounds sold
under the trademarks, Carbopol and Carbitol which have relatively short
hydrocarbon chain lengths (C.sub.2 -C.sub.8) and a low content of ethylene
oxide (about 2 to 6 EO units per molecule) are especially useful viscosity
control and anti-gelling solvents in the compositions of this invention.
This use of the alkylene glycol ethers is disclosed in the commonly
assigned copending application Ser. No. 687,815, filed Dec. 31, 1984, to
T. Ouhadi, et al., now U.S. Pat. No. 4,753,750 the disclosure of which is
incorporated herein by reference. Suitable glycol ethers can be
represented by the following general formula
RO(CH.sub.2 CH.sub.2 O).sub.n H
where R is a C.sub.2 -C.sub.8, preferably C.sub.2 -C.sub.5 alkyl group, and
n is a number of from about 1 to 6, preferably 1 to 4, on average or by
the following general formula
R.sub.1 O(CH.sub.2 CH.sub.2 CH.sub.2 O).sub.m H
where R.sub.1 is a C.sub.2 -C.sub.8, preferably C.sub.2 -C.sub.5 alkyl
group, and m is a number of from about 1 to 6, preferably 1 to 4, on
average.
Specific examples of suitable solvents include ethylene glycol monoethyl
ether (C.sub.2 H.sub.5 --O--CH.sub.2 CH.sub.2 OH), diethylene glycol
monobutyl ether (C.sub.4 H.sub.9 --O--(CH.sub.2 CH.sub.2 O).sub.2 H),
tetraethylene glycol monooctyl ether (C.sub.8 H.sub.17 --O--(CH.sub.2
CH.sub.2 O).sub.4 H), propylene glycol monoethyl ether, dipropylene glycol
monobutyl ether, tripropylene glycol monomethyl ether, etc. Diethylene
glycol monobutyl ether and tripropylene glycol monomethyl ether are
especially preferred.
In contrast, and quite unexpectedly, the small quantities of
vicinal-hydroxy containing glycols which form the present stabilizers
inhibit phase separation of the suspension.
Another useful antigelling agent which can be included as a minor component
of the liquid phase, is an aliphatic linear or aliphatic monocyclic
dicarboxylic acid, such as the C.sub.6 to C.sub.12 alkyl and alkenyl
derivatives of succinic acid or maleic acid, and the corresponding
anhydrides or an aliphatic monocyclic dicarboxylic acid compound. The use
of these compounds as antigelling agents in non-aqueous liquid heavy duty
built laundry detergent compositions is disclosed in the commonly
assigned, copending application Ser. No. 756,334, filed July 18, 1985, now
U.S. Pat. No. 4,744,916 the disclosure of which is incorporated herein in
its entirety by reference thereto.
Briefly, these gel-inhibiting compounds are aliphatic linear or aliphatic
monocyclic dicarboxylic acid compounds. The aliphatic portion of the
molecule may be saturated or ethylenically unsaturated and the aliphatic
linear portion may be straight of branched. The aliphatic monocylic
molecules may be saturated or may include a single double bond in the
ring. Furthermore, the aliphatic hydrocarbon ring may have 5- or 6-carbon
atoms in the ring, i.e. cyclopentyl, cyclopentenyl, cyclohexyl, or
cyclohexenyl, with one carboxyl group bonded directly to a carbon atom in
the ring and the other carboxyl group bonded to the ring through a linear
alkyl or alkenyl group.
The aliphatic linear dicarboxylic acids have at least about 6 carbon atoms
in the aliphatic moiety and may be alkyl or alkenyl having up to about 14
carbon atoms, with a preferred range being from about 8 to 13 carbon
atoms, especially preferably 9 to 12 carbon atoms. One of the carboxylic
acid groups (--COOH) is preferably bonded to the terminal (alpha) carbon
atom of the aliphatic chain and the other carboxyl group is preferably
bonded to the next adjacent (beta) carbon atom or it may be spaced two or
three carbon atoms from the .alpha.-position, i.e. on the .alpha.- or
.DELTA.- carbon atoms. The preferred aliphatic dicarboxylic acids are the
.alpha.,.beta.-dicarboxylic acids and the corresponding anhydrides, and
especially preferred are derivatives of succinic acid or maleic acid and
have the general formula:
##STR2##
wherein R.sup.1 is an alkyl or alkenyl group of from about 6 to 12 carbon
atoms, preferably 7 to 11 carbon atoms, especially preferably 8 to 10
carbon atoms, wherein n=1, when .sub.-- is a double bond and n=2, when
.sub.-- is a single bond.
The alkyl or alkenyl group may be straight or branched. The straight chain
alkenyl groups are especially preferred. It is not necessary that R.sup.1
represent a single alkyl or alkenyl group and mixtures of different carbon
chain lengths may be present depending on the starting materials for
preparing the dicarboxylic acid.
The aliphatic monocyclic dicarboxylic acid may be either 5- or 6-membered
carbon rings with one or two linear aliphatic groups bonded to ring carbon
atoms. The linear aliphatic groups should have at least about 6,
preferably at least about 8, especially preferably at least about 10
carbon atoms, in total, and up to about 22, preferably up to about 18,
especially preferably up to about 15 carbon atoms. When two aliphatic
carbon atoms are present attached to the aliphatic ring they are
preferably located para- to each other. Thus, the preferred aliphatic
cyclic dicarboxylic acid compounds may be represented by the following
structural formula
##STR3##
where
--T-- represents --CH.sub.2 --, --CH.dbd., --CH.sub.2 --CH.sub.2 -- or
--CH.dbd.CH--;
R.sub.2 represents an alkyl or alkenyl group of from 3 to 12 carbon atoms;
and
R.sup.3 represents a hydrogen atom or an alkyl or alkenyl group of from 1
to 12 carbon atoms,
with the proviso that the total number of carbon atoms in R.sup.2 and
R.sup.3 is from about 6 to about 22.
Preferably --T-- represents --CH.sub.2 --CH.sub.2 -- or --CH.dbd.CH--,
especially preferably --CH.dbd.CH--.
R.sup.2 and R.sup.3 are each preferably alkyl groups of from about 3 to
about 10 carbon atoms, especially from about 4 to about 9 carbon atoms,
with the total number of carbon atoms in R.sup.2 and R.sup.3 being from
about 8 to about 15. The alkyl or alkenyl groups may be straight of
branched but are preferably straight chains.
The amount of the nonionic surfactant is generally within the range of from
about 20 to about 70%, such as about 22 to 60% for example 25%, 30%, 35%
or 40% by weight of the composition. The amount of solvent or diluent when
present is usually up to 20%, preferably up to 15%, for example, 0.5 to
15%, preferably 5.0 to 12%. The weight ratio of nonionic surfactant to
alkylene glycol ether as the viscosity control and antigelling agent, when
the latter is present, as in the preferred embodiment of the invention is
in the range of from about 100:1 to 1:1, preferably from about 50:1 to
about 2:1, such as 10:1, 8:1, 6:1, 4:1 or 3:1. Accordingly, the continuous
non-aqueous liquid phase may comprise from about 30% to about 70% by
weight of the composition, preferably from about 50% to about 60%.
The amount of the dicarboxylic acid gel-inhibiting compound, when used,
will be dependent on such factors as the nature of the liquid nonionic
surfactant, e.g. its gelling temperature, the nature of the dicarboxylic
acid, other ingredients in the composition which might influence gelling
temperature, and the intended use (e.g. with hot or cold water,
geographical climate, and so on). Generally, it is possible to lower the
gelling temperature to no higher than about 3.degree. C., preferably no
higher than about 0.degree. C., with amounts of dicarboxylic acid
anti-gelling agent in the range of about 1% to about 30%, preferably from
about 1.5% to about 15%, by weight, based on the weight of the liquid
nonionic surfactant, although in any particular case the optimum amount
can be readily determined by routine experimentation.
The invention detergent compositions in the preferred embodiment also
include as an essential ingredient water soluble and/or water dispersible
detergent builder salts. Typical suitable builders include, for example,
those disclosed in the aforementioned U.S. Pat. Nos. 4,316,812, 4,264,466,
3,630,929, and many others. Water-soluble inorganic alkaline builder salts
which can be used alone with the detergent compound or in admixture with
other builders are alkali metal carbonates, borates, phosphates,
polyphosphates, bicarbonates, and silicates. (Ammonium or substituted
ammonium salts can also be used.) Specific examples of such salts are
sodium tripolyphosphate, sodium carbonate, sodium tetraborate, sodium
pyrophosphate, potassium pyrophosphate, sodium bicarbonate, potassium
tripolyphosphate, sodium hexametaphosphate, sodium sesquicarbonate, sodium
mono and diorthophosphate, and potassium bicarbonate. Sodium
tripolyphosphate (TPP) is especially preferred where phosphate containing
ingredients are not prohibited due to environmental concerns. The alkali
metal silicates are useful builder salts which also function to make the
composition anticorrosive to washing machine parts. Sodium silicates of
Na.sub.2 O/SiO.sub.2 ratios of from 1.6/1 to 1/3.2, especially about 1/2
to 1/2.8 are preferred. Potassium silicates of the same ratios can also be
used.
Another class of builders are the water-insoluble aluminosilicates, both of
the crystalline and amorphous type. Various crystalline zeolites (i.e.
aluminosilicates) are described in British Patent No. 1,504,168, U.S. Pat.
No. 4,409,136 and Canadian Patent Nos. 1,072,835 and 1,087,477, all of
which are hereby incorporated by reference for such descriptions. An
example of amorphous zeolites useful herein can be found in Belgium Patent
No. 835,351 and this patent too is incorporated herein by reference. The
zeolites generally have the formula
(M.sub.2 O).sub.x.(Al.sub.2 O.sub.3).sub.y.(SiO.sub.2).sub.z.WH.sub.2 O
wherein x is 1, y is from 0.8 to 1.2 and preferably 1, z is from 1.5 to 3.5
or higher and preferably 2 to 3 and W is from 0 to 9, preferably 2.5 to 6
and M is preferably sodium. A typical zeolite is type A or similar
structure, with type 4A particularly preferred. The preferred
aluminosilicates have calcium ion exchange capacities of about 200
milliequivalents per gram or greater, e.g. 400 meq/o g.
Examples of organic alkaline sequestrant builder salts which can be used
alone with the detergent or in admixture with other organic and inorganic
builders are alkali metal, ammonium or substituted ammonium,
aminopolycarboxylates, e.g. sodium and potassium ethylene
diaminetretraacetate (EDTA), sodium and potassium nitrilotriacetates (NTA)
and triethanolammonium N-(2-hydroxyethyl)nitrilodiacetates. Mixed salts of
these polycarboxylates are also suitable.
Other suitable builders of the organic type include
carboxymethylsuccinates, tartronates and glycollates and the polyacetal
carboxylates. The polyacetal carboxylates and their use in detergent
compositions are described in U.S. Pat. Nos. 4,144,226; 4,315,092 and
4,146,495. Other patents on similar builders include U.S. Pat. Nos.
4,141,676; 4,169,934; 4,201,858; 4,204,852; 4,224,420; 4,225,685;
4,226,960; 4,233,422; 4,233,423; 4,302,564 and 4,303,777. Also relevant
are European Patent Application Nos. 0015024, 0021491 and 0063399.
The proportion of the suspended detergen | | |
