Note: Descriptions are shown in the official language in which they were submitted.
~- r CA 02207609 1997-06-11
LIQUID LAUNDRY DETERGENT
Field of Invention
This invention relates to liquid laundry detergents and more particularly relates
to such deter~ents cont~ining zeolite builders.
Background
It is known that zeolites have been successfully employed as builders in laundrydetergents; and U.S. Patent 4,605,509 (Corkill et al.) discloses commercially attractive
detergent powders comprising 5-95% by weight of one or more water-soluble organic
surfactants, 5-95% by weight of a zeolite builder, and 5-50% by weight of one or more
a~LYiliary builders.
Developing liquid detergents comparable to the detergent powders of Corkill
et al. would be desirable. However, in order for them to be commercially attactive,
it would be necessary for these liquid detergents to have the zeolite stably suspended
therein and to have a maximum viscosity of 1000 mPa s, measured at a shear rate of
21 s-l.
U.S. Patent5,252,244 (Beaujean et al.) teaches aqueous zeolite-cont~iningliquid
detergents which are stabilized with an electrolyte s~stem comprising at least one
carbonate and at least one sulfate and which have viscosities of 2000-11,000 mPa s
(Brookfield viscosimeter, spindle NQ.671O rpm).
As taught in U.S. Patent 5,006,273 (Machin et al.), surfactant structuring--
believed to consist of an onion-like configuration comprising concentric bilayers of
surfactant molecules having water trapped therebetween--permits solid material to
be stably suspended in a liquid detergent. However, surfactant systems such as those
of Corkill et al. are frequently incapable of producing a structuring phase for a liquid
detergent. Moreover, as disclosed by Machin et al., even surfactant systems suitable
for this purpose can create another problem when used in an amount such as to provide
asurfactantcontentofatleastlO%byweight: Liquiddetergentscont~iningsuchlarger
amounts of surfactant and suspended solids are apt to have viscosities considerably
greater than 1000 mPa s unless they also contain a viscosity-reducing polymer.
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In developingCorkill-likeliquiddetergents havingthe characteristicsmentioned
above, i.e., stable suspension of the zeolite and a maximum viscosity of 1000 mPa s,
it would be advantageous to be able to avoid having to employ a viscosity-reducing
polymer in order to make the detergent pourable; and it would also be desirable for
S these liquid detergents to contain less allxili~rybuilder than the Corkill et al. powders.
Having a lower ~n~ rybuilder content would reduce the corrosivity of the deter~ents,
lessen detriment to the environment when ecologically-undesirable au~iliary builders
are employed, and provide a lower viscosity at any given zeolite level.
Summary of Invention
It has been found that li4uid detergents comprising a stable a(lueous suspensionof zeolite particles and having an auxiliary builder content of <5% by weight and a
viscosity of <1000 mPa s can be obtained without the use of a viscosity-reducingpolymerwhentheycontaincertainalkylbenzenesulfonate/nonionicethoxylatemixtures
as the surfactants.
Thus, the invention resides in an aqueous surfactant-structured liquid detergentcomprising:
(A) 5-45% by weight of suspended zeolite particles,
(B) 10-30% by weight of an alkylbenzene sulfonate/nonionic surf~c~nt
admixture in which (1) the nonionic component of the ad~ e
is an ethoxylate of an alcohol or an alkylphenol, which ethoxylate
maybe in ~(lm~ rewith an amine oxide as an optional addition-
al ingredient of the nonionic component, (2) the alkylbenzene
sulfonate/nonionic snrf~ct~nt weight ratio is in the range of 0.8-
5.3/1, (3) the amine oxide/ethoxylate weight ratio is in the range
of 0-4/1, and (4) the amine oxide/allylbenzene sulfonate weight
ratio is in the range of 0-O.S/1,
(C) an amount of ~ rybuilder in the range of 0.545% by weight
such that the nonionic surfactant/z~ ry builder weight ratio
is not higher than 3.5/1, and
(D) 35-80% byweight of water.
AA~tE~lDED S?~
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Detailed Description
Like the liquid detergents of Machin et al., the detergent compositions of the
invention are aqueous surfactdnt-structured liquid detergents. However, unlike those
known liquid detergents, they have the advantages of requiring no viscosity-reducing
S polymer in order to have a viscosity of C1000 mPas and of being able to have asuspended particle content as high as 45% by weight--a benefit because of the
contribution of zeolite to the cleaning ability of a detergent.
The alkylbenzene sulfonate used dS a component of the surfactant system may
be any of the alkylbenzene sulfonates known to be useful as surfactants. However,
10 it is preferably a salt, usually a sodium salt, of an alkylbenzene sulfonate in which the
alkyl group contains 10-15, most preferably 11-12 carbons.
As already mentioned, the ethoxylate utilized together with the alkylbenzene
sulfonate to provide the surfactant mixture of the novel-compositions may be an
ethoxylate of an alcohol or an alkylphenol. Such surfactants are well known and are
compounds which usually contain alkyl groups of 8-24 carbons and 4-30 ethoxy groups.
Among the ethoxylates which have been found to be particularly useful in the practice
of the invention are the C8-C~6 alcohol ethoxylates containing 4-12 ethoxy (EO) groups
per molecule and the octylphenol and nonylphenol ethoxylates containing 6-15 EO
groups per molecule. The ethoxylates of alkylphenols are apt to be ~lefelled when
20 it is important to keep the ~lxili~ry builder content of the compositions particularly
low.
The optional amine oxide component of the surfactant may be any of the amine
oxides conventionally employed as surfactants, typically an amine oxide corresponding
to the formula RR'R"NO in which R is a primary alkyl group cc nt~inin~ 8-24 carbons;
25 R' is methyl, ethyl, or 2-hydroxyethyl; and R" is independently selected from methyl,
ethyl, 2-hy~llo~y~thyl, and primary alkyl groups cont~ining 8-24 carbons. Such amine
oxides include, e.g., N-octyldimethylamine oxide, N,N-didecylmethylamine oxide, N-
decyl-N-dodecylethylamine oxide, N-dodecyldimethylamine oxide, N-tetradecyldimethyl-
amine oxide, N-tetradecyl-N-ethylmethylamine oxide, N-tetrddecyl-N-ethyl-2-lly~ y~;lll-
30 ylamine oxide, N-h~-Y~1ecyldimethylamine oxide, N-octadecyldimethylamine oxide, N,N-
dieicosylethylamine oxide, N-docosyldimethylamine oxide, N-tetracosyldimethylamine
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,~ .
oxide, and mi~tures thereof--the preferred amine oxides usually being those containing
one long-chain alkyl group, e.g., ~-tetradecyldimethylamine oxide.
When used, the amine oxide may constitute up to 80% of the weight of the
nonionic component of the surfactant as long as its concentration is not high enough
5 to provide an amine oxide/allylbenzene sulfonate weight ratio >0.5/1.
The allylbenzene sulfonate/nonionic surfactant proportionations required to
provide surfactant structuring of the liquid detergents can vary with the particular
~llxili~ry builder employed and with the concentrations of surfact;mt and ~
builder in the compositions--larger amounts of alkylbenzene sulfonate in the mixtures
10 being utilizable when the compositions have the higher surfactant contents, lower
allylbenzenesulfonate/nonionicsurfactantratiosbeingpermissiblewhen the detergents
have the higher ~llxili~rybuilder contents, and the range of useful sulfonate/nonionic
sur~actant ratios being narrowest at the lowest levels of ~ ry builder. However,in general, the ~ ble allylbenzene sulfonate/nonionic surfactant weight ratios are
in the range of 0.8-5.3/1, preferably 1.5~/1, and the ratios best suited for particular
compositions within the scope of the invention are easily determined by routine
experimentation.
As in Corkill et al., the ~llxili~ry builder may be any of the water-soluble
inorganic and organic salts conventionally used in detergent compositions to aid the
20 builder in sequestering "hardness" ions, such as c~lcillm and magnesium ions. Fxt~mrl~ly
of such salts are the alkali metal (e.g., sodium and potassium) carbonates,bicarbonates,
silicates, chlorides, iodides, citrates, phosphates, pyrophosphates, phosphonates,
nitrilotriacetates, polyacrylates, polyaspartates, polycarboxylates, and succinates.
Although, as indicated above, the amount of ~ Ty builder used in the
25 compositions may vary from 0.5-4.5% by weight, the quantity that is preferred in any
given instance depends on factors such as the particular surfactant mixture with which
it is utilized, the surfactant content of the composition, and the degree to which the
auxiliarybuilder might adversely affect the el.vho~ ent. Larger amounts of auxiliary
builder are needed when the compositions have the lower surfactant contents, and it
30 appears to be important to employ sufflcient ~llxili~rybuilder to ~l ev~llt the nonionic
surfactant/auxiliarybuilder weight ratio from exceeding 3.5/1. However, it is generally
AhlE~lD~ S~EET
preferred to utilize~the smaller amounts of au~iliarybuilder (i.e., 0.5-3.5~o by weight)
in combinalion with the higher surfactant contents (i.e., 20-30~ by weight) to reduce
the corrosivityof the detergents, lessen detrimentto the environmentwhen ecologically-
undesirable auxiliarybuilders are employed, and provide a lower viscosity at any given
5 zeolite level.
The particular zeolite employed as a builder in the novel liquid detergents is
not critical as long as it is a particulate sodium salt. Thus, although it may be a zeolite
of Corkill et al., other zeolites are also utilizable. It is usually a zeolite A or X or
mixture thereof, ~referably zeolite A or a zeolite A/zeolite X blend.
In the preparation of the l;quid detergents of the invention, it is not criticalto combine the ingredients in any particular order. However, it is ordinarily preferred
to dissolve the water-soluble surfactant ~ e and ~ rybuilder in water to providethe structwing phase before suspending the zeolite particles therein.
The invention is advantageous in its provision of all of its surfactant-structured
liquid detergents, but it is particularly beneficial in its permitting the formation of the
detergents having surfactant contents of 20-30% and zeolite contents of 15-45%--i.e.,
those havi~g a compositional makeup which has previously necessitated the use ofviscosity-reducing polymers to make them pourable. The liquid detergents of the
invention m ay include minor amounts of additives, such as the dyes, perfumes, enzymes,
and preser~vatives frequently used in such compositions; and they could also include
the viscosily-reducing polymers of known Iiquid detergents without losing their
surfactant ~tructuring. However, it is unlikely that it would ever be really desirable
to incorpor'3te viscosity-reducing polymers: They would be unnecessary and therefore
would merely add to the cost of the d~Lc;l~,ellL~.
The Eollowing examples are given to illustrate the invention and are not intended
as a limitationtherof. Unless otherwise specified, quantitiesmentionedin the examples
are quantit~es by weight, and codes are used to represent detelgellt ingredients as
indicated below.
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- Code Ingredient
S-l Sodium citrate
S-2 Sodium carbonate
LAS Sodium dodecylbenzene sulfonate
S AS Sodium Cl2-Cls allyl sulfate
AES Sodium lauryl ether sulfate containing three
EO (-OCH2CH2-) groups per molecule
AE A 7-EO ethoxylate of a mixture of Cl2-Cl4
alcohols
NPE l~he 9-EO etho~ylate of nonylphenol
EXAMPLE 1
Prepare a series of base compositions to determine their ability to serve as the
structuring phases of zeolite-containing liquid detergents. The ingredients used and
the amounts employed are shown in Table I.
TABLE I
Composition ¦ LAS ¦ AS ¦ AES ¦ AE ¦ NPE ¦ S-l ¦ S-2 ¦ Water
Part A - Base Compositions of Il~v~ ion
B 14 -- -- 6 -- 4 -- 76
D 14 -- -- -- 6 3 -- 77
G 18 -- -- 12 -- -- 4.165.9
Part B - Cu~ liv~ Base Compositions
A 7 -- 3 -- S -- 85
B-l -- 14 -- 6 -- 4 -- 76
B-2 -- 14 6 -- 4 -- 76
C 14 -- -- 6 -- 7 -- 73
C-l -- 14 -- 6 -- 7 -- 73
C-2 -- -- 14 6 -- 7 -- 73
E 14 -- -- -- 6 5 -- 75
E-l -- 14 -- -- 6 5 -- 75
E-2 -- -- 14 -- 6 5 -- 75
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CA 02207609 1997-06-ll
TABLEI-Pa~ B (Gont~ued)
F 14 -~ 6 7 -- 73
F-l 14 6 7 -- 73
F-2 -- -- 14 -- 6 7 -- 73
H-l 8 -- -- 12 -- 5 -- 75
H-2 -- 8 -- 12 -- 5 -- 75
H-3 -- -- 8 12 -- S -- 75
I-l 8 -- -- -- 12 6 -- 74
I-2 -- 8 -- -- 12 6 -- 74
I-3 -- -- 8 -- 12 6 -- 74
EXAMPLE 2
Test each of the base compositions of Example 1 for ability to seIve ~s a
structuringphaseby(1)stirringzeoliteparticlesthereintoformasuspensioncontaining
10-15~o byweight of suspended zeolite, (2) storing the suspension at room temperature,
15 and (3) ex~mining the suspension after two months to determine its stability. The test
shows that each of the suspensions made from a base composition within the scopeof the invention or from any of the comparacive compositions having an alphabetic
designation with no numeric suffix is stable, whereas there is appreciable settling of
the zeolite from each of the other comparative base compositions to form a second
20 phase.
As demonstrated above, the use of selected allylbenzene sulfonate/nonionic
etho~ylate ll~Lules as the s~ ct~nt~ has the unexpected result of providin~ a sllrf~rt~nt
structuring of zeolite-containing liquid detergents that is not obtained when they are
replaced with surfactant llli~sLulc;S which are norrnally considered equivalent thereto.
~5 This phenomenon is also observed when a portion of the ethoxylate is replaced with
an amine oxide and/or larger amounts of zeolite are suspended in the base compositions
to form other liquid detergents having viscosities ~1000 mPa s and zeolite contents
as high as 45% by weight.
A~1EN~ED SHE~
