Note: Descriptions are shown in the official language in which they were submitted.
1;;~0~3~Z
BACRGROUND OF THE INvENTION
This invention relates in seneral to granular
detergent compositions which comprise as essential
ingredients an alkali metal silicate, a water-
insoluble aluminosilicate and a cationic surfactant.
More particularly it relates to spray-dried detergent
compositions containing the aforesaid essential
ingredients wherein the aluminosilicate particles
are coated with the cationic surfactant in an amount
of at least 50 ppm (wt.) at least prior to being
subjected to the elevated temperatures and C02-
containing environment of the spray dryer, and pre-
ferably prior to being brought into contact with an
agueous solution of the sodium silicate.
Because of the suspected en~rophication pro-
perties attributed to phosphate builders in detergent
compositions such as those used for laundering fabrics,
it has become conventional in the art to su~stitute
for ~ome or all of the phosphate formerly employed,
a water-insoluble aluminosilicate which can be either
amorphous or crystalline. Another necessary component
of such detergents is an alkali-metal silicate, such
as sodium silicate. These compounds are found to
minimize the corrosion of washing machine surfaces
attributed to the other detergent components. In
addition it has been proposed that alkali metal
silicates are desirable components in spray-dried
detergent granules in that they aid in crutcher mix
,~
1204362
processing and also aid in maintaininq crisp free-
following granules.
It is further known, however, that there are
difficulties attendant the use of both alumino-
silicates and alkali metal silicates in the same
detergent composition. As reported in U.S.P.
4,019,gg9 issued April 26, 1977 to T. H. Ohren
et al the~e two constituents have a pronounced
tendency to aggregate through bridging of the
aluminosilicate particles. In aqueous slurry
a chemical reaction takes place which can the
theorized as involving ~Si-0~ and/or ~SiO
ionized groups of the aluminosilicate and the alkali
metal silicate which can condense to form Si-0-Si
linkages and result in the aggregatio~-by bridging.
The aggregates then fail to disperse in-the washing
medium hnd deposit on the fabric as a white floc
which i8 particularly evident OA dark fabrics.
It has been proposed to avoid the deposition
problem by limiting the amount of sodium silicate
to less tban about 3S by weight based on the
overall weight of the detergent compositions con-
taining from 5 to 95 weight per cent aluminosilicate.
This solution is disclosed in U.S.P. 3,985,669
$ssued October 12, 1976 to Rrummel et al. The
sodium silicate is employed in the form of a solid
particle. ~ third essential ingredient is a water-
soluble surface-active agent selected from the group
~20436;i~
consisting of anionic, nonionic, ampholytic and
zwitterionic surfactants. It would be desirable,
however, to be able to utilize greater concentrations
cf alkali metal ~ilicates and~or aqueous solutions
o~ alkali metal silicates in preparing detergent
compositions.
It iQ therefore the general object of the present
invention to provide a detergent composition suitable
for spray-drying which contains an aqueous solution
of alkali metal silicate in conjunction with an
aluminosilicate builder, and which is highly dispers-
ible in water even after spray-drying so that floc
deposition on fabrics is ameliorated.
SUMMA~Y OF THE INVENTION
.
A spray-dried detergenS composition comprising
an alkali metal silicate and an aluminosilicate ion-
exchanger prepared by spray drying a precursor com-
position containing aqueous alkali metal silicate
solution and a cationic surfactant-coated alumino-
~ilicate. The cationic surfactant is found to
inhibit the tendency of the alkali metal silicate
or derivatives thereof formed during spray drying
to react with the aluminosilicate particle and
create non-dispersable floc aggregates.
~204362
THE PRESEN~ INVENTION
.
The aluminosilicate components uæed in the
present invention are any of ~ynthetic or naturally
occurring zeolites heretofore proposed for u~e in
detergent compositions ~uch as (1) crystalline
aluminosili~ate zeolites having the general formula
Mx[~AIO2)x(SiO2)y]Z H20
wherein x and y are integers, preferably having a
value of at least 6; the molar ratio of x to y is
in the range of 0.1 to 1.1; and z is an integer from
about 8 to 264, preferably a value such that in
the spray-dried detergent product containing s~me,
the zeolite contains from about 10 to 30 weight-4
adsorbed water, and M is preferably sodium but can
also be potassium, ammonium or substituted ammonium;
or (2) amorphous hydrated aluminosilicate material
of the empirical formula
M (ZAl2 Y Si2)
wherein M is sodium, potassium, ammonium or sub-
stituted ammonium, z is from about 0.5 to 2, y is 1
and said material has a magnesium ion exchange
capacity of at least about 50 milligrams of CaC03
hardness per gram of ankydrous aluminosilicate; or
~3) mixtures thereof. Mixture of zeolite A and
zeolite X wherein either zeolite constitutes at
least 30 weight per cent of the overall zeolite
mixture and the other zeolite constitutes a com-
plementary amount, are especially preferred as the
aluminosilicate constituent.
~2043~;2
The c~tionic surfactant is preferably any
of the quaternary ~mmonium compounds having the
formula
l~'R2R3R4 N] Y
wherein At lea t one, but not more than two, of
the R- groups is an organic radical containing a
group selected from C~ - C22 aliphatic radical, or
an alkyl phenyl or ~lkylbenzyl radical having 10 to
16 carbon atoms in the alkyl chain, the remaining
group or groups being selected from Cl-C4 alkyl,
C~-C4 hydroxy alkyl, and cyclic structures in which
the nitrogen atom forms par~ of the ring, Y con-
stituting an anionic radical selected ~rom the
group consisting of hydroxide, halide, sulfate,
methylsulfate, ethylsulfate and phosphate ions.
The alkali metal silicates employed in pre
paring the present detergent compositions are
preferably sodium silicates with about 1.0 to 4.0
moles of SiO2 per mole of Na2o. Equivalent potassium
and lithium silicates are also useful. The alkali
metal ~ilicates are preferably employed in the form
of concentrated aqueous solutions containing from
20 to 60~ solids, but hydrated and anhydrous
silicate powders can be imparted to the overall
detergent composition along with an appropriate
amount of water if desired.
It is an important ~spect of this invention that
the aluminosilicate constituent be coated with the
cationic surfactant, or a portion thereof, before
there is contact of the aluminosilicate with the
lZ0~362
alkali metal silicate under conditions which permit
significant reaction between the~e two materials.
Advantageously, and preferably, the aluminosilicate
is c~ated with from about 100 ppm to,about 2000 ~pm
of the cationic surfactant before any contact with
~n agueous sodium silicate solution i allowed,
i.e. the aluminosilicate-cationic surfactant com-
posite i8 imparted to the crutcher as an already
prepared ma~erial. In all events the aluminosilicate
must contain the cationic ~urfactant coating before
the overall detergent composition is subjected o
spray-drying.
While ~ot wishing to be bound ~y any particular
theory, it is belie~ed that ~he principal cause of
bridging of the aluminosilicate particles to form
undesirable aggregates is a condensation reaction
between silicic acid an/or terminal silanol groups on
polymerized silicic ~pecies and -Si-OH groups of the
aluminosilicate. While relati~ely ~mall amounts of 5ilicic
acid are present in the alkali metal silicate solution
employed, there is apparently enough to cause appreciable
floc formation even at ambient room temperatures during
prolonged periods.
In the spray-dryer, however, the detergent feed
containing relatively large amounts of water is contacted
at elevated temper~tures, i.e., 500F to about 900F, by
a rather high concentration of carbon dioxide. This permits
the formation of H2C03 which then can react with the alkali
metal silicate to produ~e ~ilicic acid in accordance with
the following
7 ~0436Z
equation:
(OH~30 ~a + H2C03 - 2 Si(OH)4 ~ Na2C03
The ~ilicic acid in ~urn bonds to ~lumino6ilicate (zeolite)
~urfaces by the following equat~on:
~gOL~ ;URFACE.~EOLITE SURF'ACE
0~ Na ~ N~,~ N~a~ Nn~
OH ~ OH ~ ~ ~10 ~ OH ~2H2
Na~ O~ N~ N ~ I Na~
L I f 1 1 ~
~i Al 1 Si Al
/1\/1\/1\ 11\ /1\ /1\
~EOL2TE l;U~FACE ZEOI.ITE SURFACE
of course mon~eric 8iliCic acit is not the only active
species, and polymerized silica can also be considered
to ~e a reactive bonding agent.
The cationic surfactant coating on the aluminosilica~e
$nterferes with th~ or ~imilar ~onding reaction~
without inhibiting appreciably the ion exchange activity
of the aluminosilicate when the detergent is adted to the
washing metium.
The method of coating the aluminosilicate with the
~urfactant i8 not B crltical factor. Ortinarily the alumin-
o~ilicate i6 s$mply slurried or otherwlse washed with a
olution of the ~urfactant in ~ suitable solvent such as
water or a mixture of water and polar organic solvent ~uch
as i~opropanol.
-8- i~04~
There i8 a con~iderable attraction between the
cationic surfactant and the ~i~ic aluminosilicate, and
accordingly other types of surfactants, builders and
other traditional detergent ingred$ents can be included
in the present composition~ ~ithout 1088 of the benefits
obtained using the three essential inRredients alone.
The compositions, properties and preparation of other
organic surfactants are well represented in the patent
literature and a detailed review of such readily available
naterial will not be undertaken here. We hereinafter
disclose examples of certain classes of and individual
surfactants that can be used in the detergents of our
invention. It is not intended that the ~cope of our
invention be l~mited to these specific materials, but that
equivalent materials also be includet.
Anionic surfactants are partlcularly important in
the deter~ent compositions of our invention. Such anionic
materials include, among others, alkali metal soaps of
fatty acids, alkali metal salts of alkyl sulfuric acit
reaction products, sodium alkyl glyceryl ether sulfonates,
succinamates and anionic phosphates, one of the most
commonly uset anionic surfactants is the sodium salt of
linear alkyl benzene sulfonate (LAS) wherein the alkyl
group contains more than lO carbon atoms. LAS forms at
least a part of many of the surfactant ~ystems used in
our tetergent compounds ant may be the only surfactant
u~ed.
Nonionic surfactants are also useful and include,
~mong others, polyethylene ox~de condensate of alkyl
-9- ~20~3f;2
phenol~, condensation products of aliphatic alcohols
wieh ethylene oxide, nonyl phenol-ethylene oxide con-
densates, amine oxides and posphine oxides.
Ampholytic surfactants such as ~hë aliphatic deriva-
tives of heterocyclic secondary and tertiary 2mine~ and
zev~tterion$c surfactants such as derivatives of al~phatic
qusternary ammonium compounds are also useful.
Although sufficient ~luminosilicate-cationic surfac-
tant composite builder ant alkali metal silicate can be
used to accommodate any laundering environment it may be
desired to lnclude an auxiliary builder in the detergent
compositions of our ~nven~ion. Such auxiliary builders
$nclude salts of phosphates, pryophosphates, orthophos-
phates, polyphosphates, phosphonates, carbonates, ant poly-
hydrsxysulfonates, organic sequestering agents such as
polyacetates, earboxylates, polyaminocarboxylates and
polyhydroxysulfonates are of use in our tetergent compo-
sitions. Specific exE~ples of useful materials inclute
sodium ant potassiu~ salts of tripolyphosphate, pyrophos-
phate, hexametaphosphate, ethylenediaaminotetraacetic acit,
nitrilotriacetic acid, citric acitS citric acid isomers
ant others.
The present detergents can also include numerous
additional detergent ingredients. Antiretiposition agents
~s~ch as sodium carboxymethyl cellulose prevent certain types
of soils from retipositioning on clean fabric. Minor
detergent ingredients such as enzymes, optical brighteners
and bleaches are included to remove stains and/or improve
the appearance of the fabric. Other minor detergent
-~o- ~0436Z
ingredients ~uch a~ perfume~, anti-caking agents, dyes,
colored specks and fabric ~ofteners are added to lmprove
the properties or appearance of the detergent or the
fabric. Since detergent actives are effective ~t low
concentrations, it i5 ~mportant the bulking agents be
added to the formulation so tha~ measurement of the appro-
priate dose i8 facilitated. We have found bulking agents
such as sodium sulfates, sodium chloride and other neutral
alkali metal ~alt~ to be effective.
The detergent oompositions of this invention thus
comprise, prior to spray-drying:
(a) 0 to 30Z by weight of one or more organic ~ur-
factants;
(b) 10 to 90Z by weight of a builder system consist-
ing of
(1) 1 to 9o parts by weight of an alumino-
~ilieate having as a coating on the particles
thereof, at least 50 ppm by weight of a
cationic surfactan~, said aluminosilicate
being
(i) a crystalline aluminosilicate zeolite
having the general formula
M,~[ (A102)X (Sio2)y]z H20
wherein x and y are integers, the
molar ratio of x to y being ~n the
range of 0.1 to 1.1, and ~ is an
integer from about 8 to 264; or
(ii) an amorphous hydrated aluminosilicate
having the empirical formula
Mz(ZAl2 Ysi2)
2043~2
wherein M is sodlum, potassium, ammonium
or ~ubstituted ammonium, z is from about
0.5 to 2, y i5 1, ~aid material hav~ng a
magnesium ion-exchange capacity of~~t least
about 50 m$11igrams of CaC03 hardne~ per
gram of anhydrous aluminosilicate; or
~iii) mixtures of (i) snd ~ii); and
(2) 4 to 35 parts by weight of a water soluble alkali
metal ~ilicate ha~ing a molar composition equivalent
to 1.0 to 4.0 ~oles of SiO2 per mole of Na2O, said
alkali metal silicate being in the form of an
aqueous solution having a solids content of from
20 to 60 weight per cent.
From presently available test data i~ appears that signi-
ficant improvement in the ~nhibiting aggregation tue to alumino-
silicate bridging i obtained when as little as about 100 ppm
(wt.) of the cationic surfactant is coatet on the alumino-
silicate particles. It ~ppear~ that ~ith coatings constituting
more than about 2000 ppm (wt), no further improvement is
obtained, and in f~ct some decrease in effectiveness results
compared w$th the effectiveness of lesser amounts. Accordingly
it ~s preferred that the aluminosilicate composites contain a
coating of from about 100 ppm to 2000 ppm by weight based
on the anhydrous weight of the aluminosilicate.
~xAmple 1
In order to demonstrate the effectiveness of cationic
~urfactant-treated zeolite particles in promoting the dis-
persability of a spray-dried detergent containing high levels
of Eodium silicate and zeolite particles, two spray-dried
detergents were prepared in which the only significant dif-
12 ~Z043fiz
ference was in the zeolite constituent. In Gne sample(~) the zeolite particles were coated with about 500 ppm
of a c~tionic quaternary ammonium (alkyltrimethylammonium
chloride in which the prLmary alkyl group contains ~rom 14
to 18 carbon ~toms). In ~ample 3, the zeolite was untreated.
The composition contained:
Weight-~
_ .. .. , , . _
component Sample A SamDle B
-- .. _ ...
4A zeolite
(anhydrous) 24.8 24.3
Sodium silicate
SiO2fNa2O ~ 2.4(wt.) 9.2 9.4
CO3(as Na2CO3~ 33.4 33.2
Volatiles tLoss
on heating to
100C.) 8.8 11.7
~ Coated with 500 ppm cationic surfactant (anhydrous basis
Both samples were subjected to a di~solution screen analysis
procedure which utilized a tergotometer, a R.O.
Tap Testing Sieve ~haker, a series of seven U.S. standard sieves
(Nos. 30, 40, 50, 70, 100, 200 and 325, plus top and bottom),
drying oven, a 10~ diameter ~uchner funnel, a 3~" diameter
Buchner funnel, a 2 liter vacuum flask, a 4 liter Erlemeyer
flask, Watman No. 1 filter paper and an aspirator. The analysis
procedure was as follows:
: : (a) The clean sieve series plus sieve bottom and
3~ ~uchner funnel twith ~ilter paper) were dried in a 100C
oven, cooled to room temperature, and weighed.
(b) One liter of a ~olution of hardness water (150 ppm,
Ca++/Mg++ ~ 3/2) was heated to 50C in the tergotometer.
(c) Twenty-five grams of the detergent sample to be
te~ted was added to the hardness water in the tergotometer
~20436Z
-13-
and the content~ agit~ted for 10 minutes at 100 RPM.
(d) A ~ieve tower~ i8 prepared from the ~ieve series
~nd ~et into the 10~ diameter Buchner ~unnel, whi~ is
incerted into the four liter Erlemeyer fl~sk.
(e~ The ~ontents of the tergotometer were ~mptied
into the sieve tower. Par~icles clinging to ~he ~ergoto~eter
tub were rinsed out with distilled water and added t~ the same
tower.
(f) When ~t was ob~erved that water was no longer
dripping from the sie~e tower, the bottom was placed on the
tower and the entire apparatus placed in a 100C drying oven
for twenty-two hours.
(g) The collected liquid fraction was filtered with the
aid of vacuum using ~he weighed 3~N Buchner funnel and Whatman
No. 1 filter paper.
(h) The 3~ Buchner funnel with filtered contents was
placed in a 100C drying oven for twenty-two hours.
(i) After drying the sieve top was placed on the sieve
tower ~nd along with the Buchner funnel was allowed to cool
to room temperature.
(j) The sieve tower was placed in the R.O. Tap Testing
Sieve Shaker for three minutes.
(k) Each sieve plus bottom and Buchner funnel was weighed
and any increase in weight noted.
(1) The total solids recovered plus the percentage of
olids on each sieve were recorded. The percent~ge of solids
collected on the sieve bottom and the filter were combined to
represent the ~ine fraction.
~;~04;~;Z
-14-
Screen analysi~ of the skarting samples showed that the
median particle ~ize o~ Sample A was about 360 micrometers,
~nd ~or Sample B the median pnrticle size was about 345
~icrometers. The re~ults of the dissolution screen analysis
procedure ~howed th~t detergent Sample A (containing the
~urfactan$ coated zeolite) dispersed to the degree that the
median par~icle size was less than 44 micrometers, whereas
the compari~on Sample B Icontaining untreated zeolite particles)~
th~ dispersion was ~uch that the ~edi~n particle size was
about 120 micrometers.
