Note: Descriptions are shown in the official language in which they were submitted.
132~803
PATENT
IR 4425 /
4442(B)
TIIIXOTROPIC AQUEOUS LIQUID AUTOMATIC
DISHWASHING DETERGENT COMPOSITION
FIELD OF THE INVENTION
_ .
The present invention relates to a thixotropic aqueous liquid automatic
dishwashing detergent composition with improved anti-filming and
anti-spotting properties and method of using the detergent composition to
clean dishware, glassware, china and the like. The dishwashing
composttion contains alumina or titanium dioxide, as the anti-filming agent,
polyacrylic acid polymer builder inorganic builder salts, chlorine bleach,
bleach stable detergent and a thixo~ropic thickener.
The detergent dishwash1ng composition of the present invention
reduce8 filming and 8potting on dishware, glassware, china and the like,
particularly in hard water, and remains stable against phase separation.
More specifically, the invention relates to the use of aluminum or
titanium dioxide as an anti-filming agent and polyacrylic acid polymer
builder in thixotropic aqueous liquid dishwashing detergent compositions to
reduce ~llming and spotting.
The detergent compositions do no require an added rinse aid, are
stable in storage, do not settle and are readily redispersible and are
pourable .
The pre8ent invention al80 relates to thixotropic aqueous suspension
with improved physical ~tability. The invention relates to the use of long
chain fatty acids, metal salts of fatty acids and clay as thixotropic agents
for forming stable gel-like liquid suspensions suitable for use as liquid
automatic dishwasher detergent composition.
The present invention specifically relates to aqueous liquid automatic
dishwashing detergent compositions having thixotropic properties, improved
anti-filming and anti-spotting properties and improved physical stability
1326~03
properties, which are readily di6persible in the washing medium to provide
effective cleaning of dishware, glassware, china and the like.
PRIOR ART
Commercially available household-machine dishwasher detergents
provided in powder form have several disadvantages, e. g. non-uniform
composition; costly operations necessary in their manufacture; tendency to
cake in storage at high humidities, resulting in the formation of lumps
which are difficult to disperse; dustiness, a source of particular irritation
to users who suffer allergies; and tendency to cake in the dishwasher
machine dispenser. Liquid forms of such compositions, however, generally
cannot be used in automatic dishwashers due to high foam levels,
unacceptably low viscosities and exceedingly high alkalinity.
In addit10n, the presently used formulated powder detergents
frequently require a separate step of hand towel wiping and drying o~ the
dishwarQ, glassware, china and the like to avoid leaving undesirable traces
or film of precipitated calcium and magnesium salts. The use of liquid
detergent compo~itions present other problems. The builder salts settle in
storage and are not readily redispersed. The compositions also frequently
become thicker in storage and are not readily pourable.
Recent research and development activity has focused on the gel or
"thixotropic" form of such compositions, however, such compositions have
generally proven to be insufficiently viscous to remain "anchored" in the
dispenser cup of the dishwasher, and moreover yield spotty residues on
dishware, glassware, china and the like. Ideally, thixotropic cleansing
compositions should be highly viscous in a quiescent state, Bingham plastic
in nature, and have relatively high yield values. When subjected to shear
stresses, however, such as being ~haken in a container or squeezed
through an orifice, they should quickly fluidize and, upon cessation of the
applied shear stress, quickly revert to the high viscosity/Bingham plastic
1326803
state. Stability is likewise of primary importance, i.e. there should be no
significant evidence of phase separation or leaking after long standing.
For effective use, it is generally recommended that the automatic
dishwashing detergent, hereinafter also designated ADD, contain (1) sodium
tripolyphosphate (NaTPP) to soften or tie up hard-water minerals and to
emulsify andlor peptize soil; (2) sodium silicate to supply the alkalinity
necessary for effective detergency and to provide protection for fine china
glaze and pattern; (3) sodium carbonate, generally considered to be
optional, to enhance alkalinity; (4~ a chlorine-releasing agent to aid in the
eliminution of soil specks which lead to water spotting; and (5)
defoamer/surfactant to reduce foam, thereby enhsncing machine efficiency
and supplying regui~ite detergency. See, for example, SDA Detergents in
Depth, "Formulations Aspects of machine Dishwashing," Thomas Oberle
(1974). Clean8ers approximating to the afore-described compositions are
mostly liquid~ or powder~. Generally, su¢h compodtions omit hypochlorite
bleach, since it tends to react with other chemically active ingredients,
particularly surfactant, thereby degrading the suspending or thixotropic
agent and impairing its effectiveness.
Thus, U.S. Patent No. 3,985,ff68 describes abrasive scouring cleaners
of gel-like consistency contdning (1) suspending agent, preferably the
Smectite and attapulgite types of clay; (2) abrasive, e.g. silica sand or
perlite; and ( 3 ) filler comprising light density powdered polymers,
expanded perlite and the like, which has a bouyancy and thus stabilizing
effect on the composition in addition to serving as a bulking agent, thereby
replacing water otherwise available for undesired supernatant layer
formation due to leaking and phase destabilization. The foregoing are the
essential ingredients. Optional ingredients include hypochlorite bleach,
bleach stable surfactant and buffer, e. g. silicates, carbonates, and
monophosphates. Builders, ~uch as NaTPP, can be included as further
optional ingredients to supply or supplement building function not provided
1326803
by the buffer, the amount of such builder not exceeding 5% of the total
composition, according to the patent . Maintenance of the de~ired ( greater
than) pH 10 levels is achieved by the buffer/builder components. High pH
is said to minimize decompo~ition of chlorine bleach and undesired
S interaction between surfactant and bleach. When present, NaTPP is limited
to 5%, as stated. Foam killer is not disclosed.
In U.K. Patent Application GB 2,116,199A and GB a,140,450A, both of
which are assigned to Colgate-Palmolive, liquid ADD compositions are
diselosed which have properties desirably charaeterizing thixotropic,
gel-type strueture and wMeh inelude eaeh o~ the various ingredients
neeessary for effective detergency with an automatie dishwasher. The
normally gel-like aqueous automatlc dishwasher detergent composition having
thlxotropie propert~e~ ineludes the following ingredients, on a weight basis:
(a) 5 to 3S% alkall metal tripolyphosphate;
(b) 2,5 to 20% sodium silieate;
(e) 0 to 9% alkali metal earbonate;
(d) 0.1 to 5% ehlorine bleaeh stable, water dispersible organie
detergent aetive material;
(e) 0 to 5% chlorine bleaeh stable foam depressant;
(0 ehlorine bleach eompound in an amount to provide about 0.2
to 491 of available chlorine;
(g) thixotropie tMckener in an amount sumcient to provide the
composition wlth thixotropy index of about 2.5 to 10; and
(h) sodium hydroxide, as necessary, to adjust pH.
ADD compositions 80 formulated are low-foaming; are readily soluble in
the washing medium and mo~t effective at pH values best conducive to
improved eleaning performanee, viz, pH 10.5-13.5. The compositions are
normally of gel consisteney, i.e. a highly viseous, op&~ue jelly-like material
having Bingham plastic character and thus relatively high yield values.
Accordingly, a definite shear force is neeessary to initiate or increase flow,
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1326803
62301-1519
such as would obtaln wlthln the agltated dlspenser cup of an
energlzed automatlc dlshwasher or a stream of water. Under
such condltlons, the composltlon ls qulckly fluldlzed and
easlly dlspensed. When the shear force ls dlscontlnued, the
fluld composltlon ~ulckly reverts to a hlgh vlscoslty, Blngham
plastlc state closely approxlmatlng lts prlor conslstency.
U.S. Patent 4,511,487 dated Aprll 16, 1985 descrlbes
a low-foaming detergent paste for dlshwashers. The composltion
ls based on a mlxture of flnely dlvlded hydrated sodlum meta-
slllcate, an actlve chlorlne compound and a thlckenlng agent
whlch ls a follated slllcate of the hectorlte type. Small
amount of nonlonlc tensldes and alkall metal carbonates and/or
hydroxldes may be used.
A related Canadlan patent appllcatlon ls Serlal No.
526,708, flled January 6th, 1987. The copendlng appllcatlon
dlscloses thlxotroplc aqueous automatlc dlshwashlng detergent
composltlon which contalns a long chaln fatty acld as a thlxo- ;
troplc thlckener agent.
Another related Canadlan patent appllcatlon 19 Serlal
No. 550,065 flled October 23rd, 1987. Thls copendlng appllca-
tlon dlscloses an aqueous llquld thixotroplc clay dlshwashlng
detergent composltlon comprlslng a metal salt of a long chaln
fatty acid and a polyacryllc acld polymer or salt stablllzlng
agent.
ADVANTAGES OVER THE PRIOR ART
The thlxotroplc aqueous llquld detergent composltlons
of the present lnventlon overcome many of the prlor art prob-
lems assoclated wlth powder and llquld detergents. Because of
the addltlon of a small effectlve amount of an alumlna or tlta-
nlum dloxlde antl-fllmlng agent and polyacryllc acld polymer or
salt bullder to the composltlon an added rinse ald 18 not re-
qulred and towel wlplng and drylng are not requlred to obtaln
dry sparkllng clean dlshes, glasses, cups and eatlng utenslls.
The thlxotroplc
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62301-1519
aqueous liquid detergent compo~ition has the additional
advantages of being stable, non-settling in storage and readily
redispersible. The liquid compositions of the present
invention are easily pourable, easily measured and easily put
into the dishwashing machines.
An additional and unexpected advantage of adding the
alumina or titanium dioxide anti-filming agent to the detergent
formulatlon is that the alumlnum or tltanlum dloxlde inhibits
brown stain formation in the dishwashing machlne. The brown
stain is formed by the deposltlon ln the dishwashlng machine of
lron and/or manganese oxldes. The brown staln formatlon ls a
particularly serlous problem ln areas havlng hard water. The
alumlna or titanlum dioxide in the formulation acts on the iron
and/or manganese ln the wash water to prevent thelr deposltion
in the dishwashing machine as iron and/or manganese oxides.
ASPECTS OF THE PRESENT INVENTION
It 18 an aspect of the present lnventlon to provlde a
thlxotropic aqueous llquld automatlc dishwasher detergent
composition that has improved anti-filming and anti-spotting
properties.
It is another aspect of the invention to provide a
thlxotropic aqueous llquld detergent compositlon which is
stable in storage, easily pourable and readlly dispersible in
the dishwashing water.
A further aspect of the lnvention is to provide a
method of washing dishware, glassware, china and the like in an
automatic dishwashlng machlne using a thixotropic aqueous
liquid detergent composition in which a separate rinse aid is
not added or needed.
A still further aspect of the inventlon is to provide
a method of washing dishware, glassware, china and the like in
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an automatlc washing machine using an aqueous liquid detergent
composltion by whlch method the dishware, glassware, china and
the like are machine dried without leaving traces or a film.
It is a further aspect of this invention to provide
stable aqueous thlxotropic aqueous liquid compositions,
especially automatic dishwasher detergent compositions, by
incorporating in the aqueous suspension a small effective
amount of an alumina or titanium dioxide anti-filming agent and
polyacrylic acid polymer or salt builder. There is also added
a minor amount of a fatty acid, metal salt of a fatty acid
and/or clay thixotroplc thickener effec~ive to inhibit the
settling of the suspended particles and to prevent phase
separation.
DE~AILED DESCRIPTION OF THE INVENTION
The invention will become more readily understood
from the following detailed description of the lnvention and
preferred embodiments thereof. The lnvention concerns the
incorporatlon in an aqueous llquld detergent composition of a
small but effective amount of an alumina or titanlum dloxide
antl-filmlng agent and polyacrylic acld polymer or salt
builder. The physical stability of the composition is improved
by the additlon of a fatty acid, metal salt of a fatty acid
and/or clay thixotropic thickener. The lnvention provides a
gel-llke thixotropic aqueous liquid automatic dishwashing
detergent composition comprislng water, at least one lngredient
selected from the group conslsting of organic detergent,
chlorine bleach, detergent builder, sequestering agent, foam
lnhlbitor and mixtures thereof in which is incorporated from
about 0.5 to 5% of an alumina or titanium dioxide partlcles as
anti-filming agent and about 2 to 14% of a water soluble
polyacrylic acid polymer or salt builder. The alumina or
1~ 2g 803 62301-1519
titanium dloxide anti-filming agent has a particle size of
about 0.1 to 10 microns. The water polyacrylic acld or salt
preferably has a molecular weight of about 500 to 100,000. The
composition comprises a sufficient amount of a long chain fatty
acid or metal salt of a long chain fatty acid, or elther of the
foregoing in admixture with a clay thixotropic thickener to
provide a thixotropic index of about 2.5 to 10 and to inhibit
settllng of the suspended particles, such as alkali metal
builder salts, etc.
In accordance with this aspect, the present invention
also provides a normally gel-like aqueous llquid automatic
dishwasher detergent composition having thixotropic properties
whlch includes, on a weight basis.
(a) 5 to 35% of detergent bullder, such aæ alkali metal
tripolyphosphate;
(b) 2.5 to 40% sodium silicate;
(c) 0.5 to 5% alumlna or titanium dioxlde anti-filmlng
aqent having a particle slze of about 0.1 to 10 mlcrons;
(d) 2 to 14% polyacryllc acid polymer or salt bullder
havlng a molecular welght of about 1,000 to 100,000;
(e) 0 to 9~ alkall metal carbonate;
(f) 0.1 to 5% chlorine bleach stable, water dispersible
organlc detergent actlve materlal;
(g) 0 to 5% chlorine bleach stable foam depressant;
(h) chlorlne bleach compound ln an amount to provide
about 0.2 to 4% of avallable chlorlne;
(1) thlxotroplc thlckener in an amount sufficlent to
provlde a thlxotroplc index of about 2.5 to 10;
(;) 0 to 8% sodium hydroxide; and
(k) balance water.
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Also related to this specific aspect, the invention
provides a method for cleaning dishware in an automatic
dlshwashlng machine with an aqueous wash bath containing an
effective amount of the liquid automatic dishwasher detergent
(LADD) composition as described above. According to this
aspect of the invention, the LADD composition can be readily
poured into the dispensing cup of the automatic dishwashing
machlne and will, within just a few seconds, promptly thicken
to its normal gel-like or pa#ty state to remain securely within
the dispensing cup untll shear forces are again applied
thereto, such as by the water spray from the di~hwa~hing
machine.
The invention will now be descrlbed in greater detall
by way of specific embodiments thereof.
The LADD products of for example the prlor dlsclosure
ln the aforementioned GB 2,116,199A and GB 2,140,450A exhibit
rheologlcal
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properties as evaluated by testing product viscosity a8 a function of shear
rate. The compositions exhibited higher viscosity at a low shear rate and
lower viscosity at a high shear rate, the data indicating efficient
fluidization and gellation well within the shear rates extant within the
standard dishwasher machine. In practical term6, this means improved
pouring and processing characteristics as well as less leaking in the
machine dispenser-cup, compared to prior liquid or gel ADD products. For
applied shear rates corresponding to 3 to 30 rpm, viscosities (Brookfield)
correspondlngly ranged from about 10,000 to 30,000 cps to about 3,000 to
7,000 cps, as measured at room temperature by means of ~n LVT Brookfield
viscometer sfter 3 minutes using a No. 4 spindle. A shear rate of 7.4
sec 1 corresponds to a spindle rpm of about 3. An approximate 10-fdd
increase in shear rate produceo about a 3- to 9-fold reduction in viscosity.
The compositions of the assignee's prior invention thus exhibit threshold
nutdizsttons at lower shear rates and of s1gniflcantly greater extent in
terms ot in¢remental increases 1n shear rate versus incremental decrease in
viscosity. This property of the LADD produ¢ts of the prior invention i8
summarized in terms of a thixotropi¢ index (TI) which is the ratio of the
apparent viscosity at 3 rpm and st 30 rpm. The prior compositions have a
TI of from 2 to 10. The LADD compositions should exhibit substantial and
quick return to prior quiescent state consistency when the shear force is
discontinued.
In terms of apparent viscosity, it has been ascertained that 80 long as
the viscosity at room temperature (22+1C) measured ln a Brookfield
Viscosimeter HATD, using a number 4 spindle at 20 rpm, is less than about
20,000 cps, the composition can be readily shaken so that a thixotropic
composition can be easily "fluidized" or "liquefied" to allow the product to
be dispensed through a conventional squeeze tube bottle or other
convenient dispenser.
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62301-1519
The present invention is based upon the surprising
dlscovery that substantially improved anti-fllming and anti-
spottlng properties can be obtained by adding to the
thixotropic aqueous liquid detergent composition a smal}
effective amount of a silica anti-filming agent and polyacrylic
acid polymer or salt builder. The physical stability, i.e.,
resistance to phase separation, settling, etc. can be achieved
by adding to the composition a small effective amount of a
thixotropic thickener and stabilizing agent.
_NTI-FILHING AGENTS
The alumina or titanium dioxlde anti-filming agent
materials that can be uged are readily commercially available.
The alumlna material that can be used as an anti-filming agent
is insoluble in water and has the formula Al203. Suitable
materlal~ are available under the trademarks Alumlnum Oxide C,
Degussa and Catapal D, Vista. A preferred alumina material i~
Alumlnumoxld C~.
The particle slze of the alumlna and titanlum dloxlde
material that 1~ used iæ important in achieving the desired
anti-filming properties.
The alumina or titanlum dloxlde particles that are
used are finely dlvided and can have a particle size of about
0.10 to 10 mlcron~, preferably 0.50 to 8 mlcrons and more
preferably about 1.0 to 5.0 mlcrons. The llica particles of
this size and ln the amount used herein are not abrasive.
The finely divided alumina or titanium dioxide
materlal partlcles ln the dishwashing wash act to coagulate
proteinaceous particulate soils and keeps them in suspenslon
and with the polyacrylic acid polymer or salt acts as an anti-
redeposition agent to prevent them from depositing on the cleanglass and dishware.
~Trade-mark 10
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... . . . , . . . ~ , - .
1 3 2 g~3 62301-1519
Without intending to limit the invention in any way
it is theorized that the alumina and tltanium dioxide anti-
fllmlng agents function in the following manner. The glass
surface of vitreous glassware contain negative charges on their
surface through the Si-0 bonds. Usually the oxygen atoms carry
these charges. It is postulated that these negatively charged
lons will
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attract pos~tively charged particles snd thereby will form sn "artificial soil"
layer. This protective layer will then repel the regular food 80il and will
increase the anti-redeposition property of the automatic dishwushing
detergent. The ~umina and titanium dioxide particles, respectively, will
generate poslti~rely charged p-rticles which will bond themselves to the
glssswsre surfsce to form the artificial soil layer which will prevent the
formation of film.
The amount of alumins or titanium dioxtde anti-fflming agent that can
be used to achieve tho dedred improvement in fflming and spotting will
depend on the hsrdness ot the wster, detergent active compound, inorganic
salt~ and other ADD ingredients. The aluminum or titanlum dioxide
anti-fllming ~gent is partlculsrly eftective in hard wssh water of, for
examplo, 300 ppm hsrdness or more.
The smount ot alumina or titsntum dioxide snti-fllm sgent thst is used
can b~ bout 0.5 to 5~, pre-erabb about 1 to ~% and moro preferably sbout
1.S to 3~ by wdght b-sed on tho welght ot the entire compodtlon.
The alumina snd tltsnlum dloxide csn e~ch be used alone or csn be
used mixed together snd/or mixed with 8 si1ica snti-~llming sgent. When
the antt-filmtng agents sre used mlxed together the wdght percent amounts
; 20 mentloned sbove are the totsl for the ingredients in the mixture.
POLYACRYLIC ACID POLYMPRS ~ND SALTS THEREOP
The polyscrylic scld polymers snd sslts thereof thst can be used sre
generslly comm-rcially svaihble Imd sre brietly described a8 follows.
The polyscrylic scid polymers snd salts thereof that can be used
comprise wster soluble low moleculsr weight polymers havlng the îormula
I-IRl 12
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R3 COOM n
1326803
wherein the Rl, R2 and R3 can be the same or different and can be
hydrogen, Cl-C4 lower alkyl, or combinations thereof. The value of n is 5
to 1000, preferably, 10 to 500, snd more preferably 20 to 100. M
represents hydrogen, or an alkali metal such as sodium or potassium. The
pre&rred substituent for M is sodium.
The preferred Rl, R2 and R3 groups are hydrogen, methyl, ethyl and
propyl. Preferred acrylic acid monomer i8 one where 1~1 to R3 are
hydrogen, e. g. acrylic acid, or where R1 and R3 are hydrogen and R2 is
methyl, e.g. methyl acrylic acid monomer.
The degree of polymerization, i . e. the value of n, i9 generally
determined by the limit compatible with the solubility of the polymer in
water. The terminal or end groups of the polymer are not critical and can
be H, OH, CH3 or a low molecular weighe hydrocarbon.
The poly~crylic acid polymers and salts thereof can have a molecular
weight of 500 or 1,000 to 100,000, preferably 1,500 to 50,000 and especially
preierably 2,000 to 10,000.
r ~ SpeclNc polyacrylic acid polymers which can be used include the
A Acrysol~LMW acrylic acid polymers from Rohm snd Haas, such as the
Acrysol LMW-45NX, a neutralized sodium salt, which has a molecular weight
of about 4,500 and Acrysol LMW-20NX, a neutralized sodium salt, which hss
a molecular weight of about 2, 000 . The low molecular weight acrylic acid
polymers can, for example, have a molecular weight of about I, 000 to
10, 000 . Another polyacrylic acid polymer that can be used is Alcosperse~
110 (from Alco) which is a sodium salt of an organic polycarboxylate and
2S which has a molecular weight of about 100,000.
The above polyacrylic acid polymers and salts thereof can be made
using procedures known in the art, see for example U.S. Patent 4,203,858.
The amount of polyacrylic acid polymer or salt builder that can be
used to achieve the desired improvement in anti-filming and anti-spotting
12
1~26803 62301-1519
properties will depend on the hardness of the water, detergent
active compound, inorganic salts and other ADD ingredients.
The polyacrylic acid or salt builder is particularly
effective in reducing spotting in hard water of, for example,
300 ppm hardness or more.
Generally, the amounts of the polyacrylic acid
polymer or salt that can be used are in the range of from about
2.0 to 14%, preferably from about 3.0 to 12%, especially
preferably about 4 to 10~.
THIXOTROPIC THICKENERS
The thixotropic thickeners or suspending agents that
can be used ln accordance wlth the present inventlon to provide
the aqueous medlum wlth thlxotropic properties may be organic,
for example, fatty acid or fatty acld polyvalent metal salt~ or
inorganlc collold forming clay materials. The thixotropic
thickeners ~hould be stable to high alkalinity and stable to
chlorine bleach compounds such as sodium hypochlorite. The
preferred thixotropic thlckeners comprlse the fatty aclds, the
fatty acld polyvalent metal salts and the lnorganlc, collold-
formlng clays of smectlte and/or attapulglte types. The amountof the thlxotroplc thlckener used wlll depend on the particular
thickener used, but sufficlent thlckener 1B added to the
formulatlon to provlde the compo~ltion with a thixotropy index
of about 2.5 to 10.
The preferred fatty acld thixotropic thickeners are
the higher allphatlc fatty monocarboxylic acids having from
about 8 to about 22 carbon atoms, more preferably from about 10
to 20 carbon atoms, and especially preferably from about 12 to
18 or 16 to 20 carbon atoms, lnclusive of the carbon atom of
the carboxyl group of the fatty acid. The aliphatic radical
1 3 2 6 8 03 62301-1519
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
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:~ 1326803 62301-1519
acld, soya fatty acid, etc., or from synthetlc sources avall-
able from lndustrial manufacturlng processes.
Thus, examples of the fatty aclds whlch can be used
as thlckeners lnclude, for example, decanolc acld, laurlc acld,
dodecanolc acld, palmltlc acld, myrlstlc acld, stearlc acld,
olelc acld, elcosanolc acld, tallow fatty acld, coco fatty
acld, soya fatty acld and mlxtures of these aclds. Stearlc
acld and mlxed fatty aclds, e.g. coco fatty acld, are pre-
ferred.
The amount of the fatty acld thlckener to achleve the
deslred values of thlxotropy and physlcal stablllty wlll depend
on such factors as the nature of the fatty acld, detergent
actlve compound, lnorganlc salts, especlally TPP, other LADD
lngredlents, as well as the antlclpated storage and shlpplng
condltlons.
Generally, however, amounts of the fatty acld thlxo-
troplc agent that can be used are ln the range of from about
0.03 to 0.5%, preferably from about 0.03 to 0.2%, especlally
preferably from about 0.05 to 0.15%, provlde the de~lred long
term stablllty and absence of phase separatlon.
The polyvalent metal ~alts of the above fatty aclds
can also be used ln the present lnventlon as thlxotroplc thlck-
ener agents. Sultable metal salt thlxotroplc thlckeners are
dlsclosed ln Canadlan appllcatlon Serlal No. 546,121 flled
September 4, 1987.
The preferred metals are the polyvalent metals such
as magneslum, calclum, alumlnum and zlnc.
Generally, the metals may be present ln the dlvalent
to pentavalent state. Preferably, the metal salts are used ln
thelr hlgher oxldatlon states. Naturally, for LADD composl-
tlons, as well as any other appllcatlons where the lnventlon
composltlon wlll or may come lnto contact wlth artlcles used
for the handllng, storage or servlng of food products or whlch
otherwlse may come lnto contact wlth or be consumed by people
or anlmals, the metal salt should be selected by taklng lnto
conslderatlon the toxlclty of the
14
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1~6803
metal. Por this purpose, the calcium and magnesium salts are especially
highly preferred as generally safe food additives.
Many of these metal salts are commercially available. For example, the
aluminum salts are available in the triacid form, e. g. ~luminum steurate as
S aluminum tristearate, Al((~l7-H35C00)3. The monoacid ~alts, e.g. aluminum
mono8tearate, Al(OH)2(C17H35C00) snd diacid salts, e.g. aluminum
distearate, Al(OH)C17H35C00)2, and mixtures of two or three of the
mono-, di- snd tri-acid salts can be used for those metals, e. g. Al, with
valences of +3, and mixtures of the mono- and di-acid salts can be used for
those metals, e.g. Zn, with valences of +2. It is more preferred that the
diacids of the +2 valent metals and the trlacids of the +3 valent metals, the
tetraacid~ of the +4 metals, and the pentacids of the +5 valent metals, be
used in predom1nant amounts. For example, at least 309~, preferably at
least S0%, especially preferably from 80 to 100% of the total metal salt should
be in the h1ghest po~otble oxidation state, i.e. ea¢h of the possible valence
sites is occupied by a fatty acid residue.
The metal salts, as mentioned above, are generally commercially
avdlabb but can be eadly produced by, for example, saponification of a
fatty acid , e . g. animal at , stearic acid , etc ., or the corresponding i'atty
acid ester, followed by treatment with an hydroxide or oxide of the
polyvalent metal, for exsmple, in the case of the aluminum salt, with alum,
alumina, etc.
Calcium stearate, i . e . calcium distearate, magnesium stearate, i . e .
magnesium distearate, aluminum stearate, i.e. aluminum tristearate, and zinc
steflrate, i.e. zinc distearate, are the preferred polyvalent fatty acid salt
stabilizers. Mixed fatty acid metal salts, such as the naturally occurring
acids, e. g. coco acid, as well as mixed fatty acids resulting from the
commercial manufacturing process sre also advantageously used a~ an
inexpensive but effective source of the long chain fatty acid.
1326803
The amount of the fatty acid salt stabilizers to achieve the desired
enhancement of physical stability will depend on such factors as the nature
of the fatty acid sslt, the nature ~nd amount of the thixotropic agent,
detergent active compound, inorgsnic salts, especislly TPP, other LADD
ingredients, as well as the anticipsted storsge and shipping conditions.
Generally, however, amounts of the polyvalent metal fatty acid salt
stabilizing agents in the rsnge of from sbout 0.02 to 1%, preferably from
about 0 . 06 to 0 . 896, especially prefersbly from about 0 . 08 to 0 . 4%, provide
the long term stsbility snd absence of phase separation upon standing or
during transport at both low and elevated temperatures as are required for
a commercially acceptable product.
There may also be used in the present invention the conventional
inorganic thixotropic clay thickeners. The clay thickeners may be used in
small amounts in combination with the fatty acid thickeners or in
combination wtth fatty acid polyvalent metal salt thlckener8. The clay
thickener8, however, may be used by themselves as the thixotropic
thickeners.
The preferred clay thickeners comprise the inorganic, colloid forming
clay8 of smectite and/or attapulgite types.
Smectite clays include montmorillonite (bentonite), hectorite,
attapulgite, smectite, saponite, and the like. Montmorillonite clays are
preferred and are available under tradenames such as Thixogel (Registered
Trademark) No. 1 and Celwhite (Registered Trademark) GP, H, etc., from
Georgia Kaolin Company; and Eccagum (Registered Trsdemark) GP, H, etc.,
from Luthern Clay Products. Attapulgite clays include the msterials
.~ commercially available under the~ittagel (Registered Trademark),
i. e . Attagel 40, Attagel 50 and Attagel 150 from Engelhard Minerals and
Chemicals Corporation. Mixtures of smectite and attapulgite types in weight
ratios of 4:1 to 1:5 nre also useful herein. Thickening or suspending
sgents of the foregoing types are well known in the art, being described,
16
13268~3
for example, in V.S. Patent No. 3,985,668 referred to above. Abrasives or
polishing agents should be avoided in the LADD compositions as they may
mar the surface of fine dishware, crystal and the like.
When used in combination with the fatty acids or the fatty acid
polyvalent metal salts, the clsy thixotropic thickeners are used in amounts
of 0.1 to 3%, preferably 0.1 to 2.5% and more preferably in amounts of 0.1
to296.
When the clay thixotropic thickeners are used alone as the thixotropic
thi¢kener agent they can be used in amounts of about 1,5 to 8%, preferably
2 to 5% by weight of the formulstion.
Generally, LADD effectiveness is directly related to (a) available
chlorine levels; (b) alkalinity; (c) solubility in washing medlum; and (d)
foam inhibltlon. It is preferred herein that the pH of the LADD composition
be st least about 9, S, more preferably from about 10 . 5 to 13 . S and most
preferably at least about 11,5. At the relatlvely lower pH values, the
LADD product is too viscous, i.e. 801id-like, and thus not readily fluidized
under the shear-for¢e levels created within the dispenser cup under normal
machine operating conditions. Addition of NaOH is thus often needed to
increase the pH to withln the above range8, and to increase flowability
properties. The presence of carbonate is also often needed herein, since it
acts as a buffer helping to maintain the desired pH level. Excess carbonate
is to be avoided, however, since it may cause the formation of needle-like
crystals of carbonate, thereby impairing the stability, thixotropy and/or
detergency of the LADD product, as well as impairing the dispensibility of
the product from, for example, squeeze tube bottles. Caustic soda (NaOH)
serves the further function of neutralizing the phosphoric or phosphonic
acid ester foam depressant when present. About 0.5 to 3 wt96 of NaOH and
about 2 to 9 wt~ of sodium carbonate in the LADD composition are typical,
although it should be noted that sufficient alkalinity may be provided by
the NATPP and sodium silicate.
17
1326803
The NsTPP may be employed in the LADD composition in a range of
about 8 to 35 wt%, prefer~bly about 20 to 30 wt%, and should preferably be
free of heavy metal which tends to decompose or inactivate the preferred
sodium hypochlorite and other chlorine bleach compounds. The NaTPP may
be anhydrous or hydrated, including the stable hexahydrate with a degree
Or hydration of 6 corresponding to about 18% by weight of water or more.
Actually, in view of the stabUity of the hexahydrate, the presence of some
water of hydration is highly effective, serving it is thought to form seeds
of the stable hexahydrate which expedites hydration and solubilization of
the remaining NaTPP particles. If only the hexahydrate is used, the
detergent product may be too liquid. Conversely, if only the anhydrous
NaTPP is used, the product may, in some cases, be too thick and,
therefore, unsuitable. Bepecially preferred LADD compositions are
obtained, for exampb, when using a 0,5:1 to 2:1 we1ght ratio of anhydroua
lS ¦ to hexahydrated NaTPP, values of about 1:1 being particularly preferred.
Poam inhibltion is important to increase dishwasher machine efficiency
and mln1mize dostabilizing effects which might occur due to the presence of
excess foam within the washer during use. Foam may be sufficiently
reduced by suitable selection of the type andlor 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 NaTPP which has a water
softening effect may aid in providing the desired degree of foam inhibition.
However, it i8 generally preferred to include a chlorine bleach stable foam
depressant or inhibitor. Particularly effective are the alkyl phosphonic acid
esters o- the formula
1l
HO--IP--R
OR
1326803
available for exsmple from BASF-Wyandotte (PCUK-PAE), and especially the
alkyl acid phosphate esters of the formula
O
HO--P--OR
OR
available, for example, from Hooker (SAP) snd Knapsack (LPKn-158), in
which one or both R groups in each type of ester may repre~ent
independently a Cl2_20 alkyl group. Mixture~ of the two type8, or any
other chlorine bleach stable types, or mixtures of mono- and di-esters of
the same type, may be employed . 13 specially preferred is a mixture of
l mono- and di-C16 18 alkyl acid phosphate esters such as
l monostearyl/distearyl acid phosphates 1.2/1 (Knapsack). When employed,
proportions of 0,01 to 5 wt%, preferably 0.1 to 5 wt%, especially about 0.1
to 0.5 wt%, of foam depressant in the composition is typical, the weight
ratio of detergent active component (d) to foam depressant (e) generally
ranging from about 10 :1 to 1:1 and preferably about 4 :1 to 1:1. Other
defoamers which may be used include, for example, the known silicones.
Although any chlorine bleach compound may be employed in the
compositions of this invention, such as dichloro-isocyanurate,
dichloro-dimethyl hydantoin, or chlorinated TSP, alkali metal, e.g.
potassium, lithium, magnesium and especiallr sodium hypochlorite is
preferred. The composition should contain sufficient chlorine bleach
compound to provide about O . 2 to 4 . 0% by weight of available chlorine, as
determined, for example, by acidification of 100 parts of the composition
with excess of hydrochloric acid . A solution containing about O . 2 to 9 . 0%
by weight of sodium hypochlorite contains or provides roughly the same
percentage of available chlorine. A solution containing about 0.8 to 1.6% by
weight sodium hypochlorite contains about 0.8 to 1.6% by weight of available
chlorine and i8 especially preferred. For example, sodium hypochlorite
1~268~3
(NaOCI) solution of from about 11 to about 13% available chlorine in amounts
of about 3 to 20%, preferably about 7 to 12%, can be advantageously used.
The sodium silicate, which provides alkalinity and protection of hard
surfaces, such as fine china glaze and pattern, is employed in an amount
ranging from about 2.5 to ~0 wt9~, preferably about 10 to 35 wt%, in the
composition. At the higher levels specified herein for example at levels
greater than about 10 wt% the silicate al80 provides increased antispotting
action. The sodium silicate is generally added in the form of an aqueous
solution, preferably having an Na20:SiO2 ratio of sbout 1:2.2 to 1:2.8, for
example, 1:2.4. Most of the other components of the composition, especially
NaOH, sodium hypochlorite and foam depressant may also be added in the
~orm o- an aqueous dispersion or solution.
Detergent active material useful herein must be stable in the presence
of chlorine bleach, especially hypochlorite bleach, and those of the organic
anionic, amine oxide, phosphine oxide, sulphoxide or betaine water
dispersible surfactant types are pre-erred, the flrst mentioned anionics
being most preferred. They are used in amounts ranging rom about 0.1 to
5% pre-erably about O . 3 to 2 . 0% . Particularly preferred surfactants herein
are the Ihear or branched alkali metal mono- and/or di-(C8 14) alkyl
diphenyl oxide mono andlor disulphates, commercially available for example
as DOWFAX (Registered Trademark) 3B-2 and DOWFAX 2A-1.
In add1tion, the surfactant should be compatible with the other
ingredients of the composition. Other suitable surfactants include the
primary alkylsulphates, alkylsulphonates, alkylaryl-sulphonates and
sec.-alkylsulphates. Examples include sodium C10_18 alkylsulphates such as
sodium dodecylsulphate and sodium tallow alcoholsulphate; sodium C10 18
alkanesulphonates such as sodium hexadecyl-l-sulphonate and sodium C12 18
alkylbenzenesulphonates such as sodium dodecylbenzenesulphonates. The
corresponding potassium salts may also be employed.
ZO
1326803
As other suitable surfactants or detergents, the amine oxide
surfactants ~re 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 surractant phosphine oxide RaRlPO or sulphoxide RRlSO can
be employed. Betaine surfactants are typically of the structure R2RlN -
RnCOO, in which each R represents a lower alkylene group having from 1
to 5 carbon atoms. Specific examples of these surfactants are
lauryl-dimethylamine oxide, myristyldimethylsmine oxide, the corresponding
phosphine oxides snd sulphoxides, and the corresponding betaines,
including dodecyldimethybmmonium scetate, tetrsdecyldiethylammonium
pentanoato, hexsdecyl-dimethylsmmonium hexsnoste and the like. For
biodegradability, the alkyl groups in these surfsctsnts should be linear,
lg and su¢h compounds are preferred.
Sur~actants of the foregoing type, all well known ln the srt, are
described, for example, in U. S . Patents 3 ,085 ,668 and 4, 271,030.
The amount o~ water contained in these compositions should, of course,
be neither 80 hlgh a8 to produce unduly low visco~ity and fluidity, nor 80
low a8 to produce unduly high viscosity and low flowsbility, thixotropic
properties in either case being diminished or destroyed. Such smount is
readily determined by routine experimentation in any particular instsnce,
generally ranging from about 25 to 75 wt%, pre(ersbly sbout 50 to 65 wt%.
The water should also be preferably deionized or softened. These amounts
2~ of water in the composition include the water added as parts of the liquid
solutions of other ingredients, but do no include bound water, for example
that in NaTPP hexahydrate.
Other conventional ingredients may be included in these compositions
in small amounts, generally less than about 3 wt%, such as perfume,
hydrotropic agents such as the sodium benzene, toluene, xylene and cumene
~ 1326803
sulphonate~, preservatives, dyestuffs and pigments and the like, all of
course being stable to chlorine bleach compound snd high ~Ikalinity
(properties of all the components). Especi~lly preferred for coloring are
the chlorinated phthalocyanines and poiysulphides of aluminosilicate which
provide, respectively, pleasing green and blue tints.
The liquid ADD compositions of this invention are readily employed in
known manner for washing dishes, glssses, cups, esting utensils and the
like in an automatic dishwasher, provided with a suitable detergent
dispenser, in an aqueous wash bath contdning an effective amount of the
10 composition.
In a preferred embodiment of the inYention the aqueous liquid
dishwsshing detergent composition is Çormulated using the below named
ingredients.
l Component Weight Percent
Alkali Metal Tripolypho~phate 10-25
Sodium Biltcate (47.5~) 15-40
Alumina or Titanium Dioxide Anti-filming Agent 1-4
Polyacrylic Acid Polymer or Salt 3-12
Alakli Metal Carbonate (anhydrous) 2-8
Chlorine Bleach Stable, Water Dispersible Organic
Detergent Active Material 0.5-3
Chlorine Bleach Stable Foam Depressant 0.10-3
Chlorlne Bleach Compound 0.2-4
Fatty Acid Thixotropic Thickener 0.03-0.5
Sodium Hydroxide (50%) 2-6
Balance Water
The thixotropic aqueous liquid automatic dishwashing detergent
compositions of the present invention can contain conventional dishwashing
detergent composition additives. The formulations can be prepared with
1326803
commerclally available solid powder builders, and/or the ingredients can be
mixed and the formulations ground to a desired particle size.
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 exdmples.
All amounts and proportions referred to herein are percent by weight
of the composition unless otherwise Indicated.
The present invention is further illu~trated by the ~ollowing examples.
23
1326803 62301-1519
ExamPle 1
A thixotropic aqueous liquid automatic dishwashing
detergent composition is formulated from the following
ingredients in the amounts specified.
Component Weiqht Percent
Deionized Water 31.04
Knapsack LPKN-158 Foam Depressan~(l) 0.16
Sodium Hydroxide (50%) 2.34
Sodium Carbonate (anhydrous)4.88
Sodium Tripolyphosphate (anhydrous) 11.70
Sodium Tripolyphosphate (hexahydrate) 11.70
Alumina Anti-fllming Agent(2)2.5
Sodium polyacrylate polymer builder(3)
(A.I.) 8.00
Gel White H Clay 1.22
Alumlnum Stearate Thlxotropic Thickener 0.09
Dowfax 3B-2 Surfactant(4) 0.78
Sodium Hypochlorite (11%) 8.78
Sodlum Sillcate (1/2.23 - 43.5%) 16.81
Graphtol Green Color 0.002
100.002
(1) Mixture of mono and distearyl (C16-C18) alkyl esters of
phosphoric acid, mole ratio 1.1.3.
(2) Aluminumoxid C (Degussa) has a particle s~ze of about
4 microns and is available from Degussa Corporation.
(3) Alcosperse 149, about 2000 mw, available as a 40%
solution.
(4) Na mono- and didecyl dlphenyl ether disulfonate
(45~ solution).
3d
The ingredients are mixed following the procedure
of Canadlan patent appllcation Serial No. 546,121 filed
September 4th, 1987.
(The ingredients are added to the water generally in
the order listed and gently stirred until a homogeneous mixture
is obtained). The formulation is tested by washing glassware
and dishware at a temperature of
B 24
~ 13~`$~1~
¦ 120F in hard water (300 ppm hardness) in an sutomatic dishwushing
¦ machine and the clean and dried dishe~ are found to have no apparent film
¦ and very few apparent ~pot8.
¦ Example 2
¦ In order to demonstrate the effect of adding the silica anti-filming
agent, formulations are prepared with and without the silica anti-filming
agent and are compsred to a commercially available powder detergent
composition.
The compositions are formulated to contain the following ingredients.
A B C D E
Alumina Alumina Titanium Tltanium ~o Anti-film
Poly- No Poly- Dioxide Dioxide Agent/
acrylate acrylate Poly- No Poly- Polyacrylate
Component acrylate acrylate
Deionized Water 31,04 39.04 31.04 39.04 33.54
Knapsa¢k LPKN-158
Poam Depreos~nt O.lB 0,16 0.1B 0,16 0.16
Sodium Hydroxide (50~) 2.34 2.34 2,34 2.34 2,34
Sodlum Carbonate
(anhydrous) 4.88 4.88 4.88 4.88 4.88
Sodlum Trlpolyphosphate
(anhydrous) 11.70 11.70 11.70 11.70 11.70
Sodium Tripolyphosphate
(hexahydrate) 11.70 11.70 11.70 11.70 11.70
Anei-filming Agent 2.50 2.50 2.50 2.50 ---
Sodium ~yacrylate
Polymer (A.l.) 8.00 --- 8.00 --- 8.00
Cel White H Clay 1.22 1.22 1.22 1.22 1,22
Aluminum Stearate
Thixotropic Thickener 0.09 0.09 0.09 0-09 0-09
Doxfnx 3B-2 Surfactant 0.78 0.78 0.78 0.78 0.78
Sodium
Hypochlorite (11%) 8.78 8.78 8.78 8.78 8.78
Sodium Silicate
(1/2.23 - 43.5%) 16.81 16.81 16.81 16.81 16.81
100.00 100.00 100.00 100.00 100.00
(1) Alcosperse 149.
6 2 30 1 - 1 5 1 9
1326803
¦ The Ingredlen~s ore mlxed In n conventlonnl manner or cnn be mixe l
followlng the procedure of Canadian patent application
¦ Serial No. 546,121 filed September 4th, 1987.
¦ (The Ingredlents nre added to the water generolly In thc order llstcd
ond genlly slirrecl untll a homogeneouY mlxlure 18 ol)tDIned. ) Tlle
formulntlon i~ tested by waehlng glassware at 12~F In hard wnter (300 ppm
hardnes~) .
I The three abolre formulatlon~ (A) (U) (C) ~D) and (E) wore tcstcd
¦ ond compared wllh o commerclQlly avalloble powder outomollc dlshwasher
detergent formulallon F. The formulatlon~ were lesled In a Kenmore
oulomalic dlshwosher uslng the procedure de~cribed In ASTMD ~56G-7~
except lhat only four cleanlng cyclee nre u~ed. The fllming and epotllng
l are evalualed accordlng to lhe following sc~le~:
¦ Fllm natlng Scale .
l. ~eet no apparent film
¦ 2 FYlmlng slighl becomlng apparent
¦ J. Noticeflble film increasing
¦ 4. Continued Incrense of slgnlflcent film
¦ 5. Nlmlng becomlng exceeelve
G Nlmlng hlE~h exces~Jve buildup
¦ 7. Continued increa~e of exces~ive film.
¦ Spot natlng Scule
¦ A UeHt - no epota
2S ¦ 1~. Very few spot~ apparent
¦ C. Dl~tlnct
¦ D. Slgnlflcant coverage approxlmately 50~.
The ree~ obtnined a re reported In lhe below Toble 1
A 25
.~ , . . .
~ - 132~803
TABLE 1
¦ Formulstion Performance Rating
¦ Spot Fqlm
(A) Alumina/Polyacrylate B 1-2
l (B) Alumina/No Pdyacrylate B-C 2
¦ (C) Titanium Dioxide/Polyacrylate B 2-3
(D) Titanium Dioxide/No Polyacrylate B-C 2-3
(E) No Anti-film Agent/Polyacrylate B-C 3-4
(F) Commercial Powder DetergentB-C 3-4
l The producte (A) and (C) left no spot on glasswares except onettwo
10 ¦ prong marks and were rated (B). The product (E) with no anti-film agent
¦ left ~ significant uniform film B-C, 3-4 on glasswares. However, significant
¦ spotting and filming improvement were obtained with the formulations .
¦ contdning both snti-filming agent and polyacrylate.
27
1 ~32~8~3
¦ Example 3
¦ A thixotropic aqueous liquid automatic dishwashing detergent
¦ composition i8 formulated from the following ingredients in the amounts
¦ specified.
¦ Component Weight Percent
¦ Deionlsed Water 26.8
¦ Knap8ack LPKN-158 Foam Depressant0.16
¦ Sodium Hydroxide (50%) 2.34
¦ Sodium Carbonate (anhydrous) 4.88
¦ Sodium Tripolyphosphate (anhydrous) 11.70
¦ Sodium Tripolyphosphste (hexahydrste) 11.70
¦ Alumina ~nt1-filming Agent 2.50
¦ Stearic ~cid Thixotroplc Th~¢kener0.10
¦ Sodium Polyacrylato (MW 2000) 6.00
¦ Dow~ax 3B-2 Surfactant .~
¦ Sodium Hypochlorite (11%) 7.ô1
¦ Sodium Silicste (1/2.4-47.5~) 25.B0
¦ Graphitol Greon 0.01
1 100.00
l The ingrodient~ sre added to the water genersUy in the order listed
20 ¦ and gently st1rred until a homogeneous mixture is obtained.
¦ The formulstion is tested by washing glassware at 130F in hard water
¦ (300 ppm hardness) in an sutomstic dishwsshing mschine. The cleaned and
¦ dried glassware are found to have no apparent film and very few appsrent
¦ epots.
25 ¦ The thixotropic squeous liquid sutomstic dishwashing detergent
¦ compositions of the present invention provide improved film properties.
¦ The invention is not to be limited by the sbove disclosure and Exsmples
which are given as illustrstlons only. The invention is to be interpreted in
accordance with the below claims.
