Note: Descriptions are shown in the official language in which they were submitted.
~Z~73~2
This invention relates to particulate synthetic
organic detergent compositions and ~ethods for the manufac-
ture thereof. More particularly, it relates to fabric soften-
ing detergent compositions containing bentonite, agglomerated
from finely divided bentonite powder onto surfaces of larger
detergent composition particles, and to processes of effect-
ing such agglomeration.
Spray dried detergent compositions are well known
and comprise a major proportion of particulate heavy duty
laundry products sold for use in automatic washing machines.
Because laundry washed with such compositions may be uncomfort-
ably hard or "boardy", especially if dried on a washline
instead of in an automatic dryer, fabric softeners have been
emplo~ed, sorne~imes in the rinse cycle of the washing process
and sometimes in an automatic laundry dryer, to deposit
softening material onto surfaces of the laundry. Waxv fabric
softeners, such as quaternary ammonium halides~have also been
included in detergents,but only a minor proportion of such
softener will not be discharged with the wash water, leaving
little depos ted on the laundry. Also, such cationic ma-
terials react witn anionic detergents and fluorescent bright-
ener dyes and therefore are detrimental. Bentonite has been usedin detergent compositions as a filler and as a softening
agent. The bentonite particles, of very small ultimate
particle sizes, tend to adhere to the material being washed
and provide lubricating sites on such material, making it
softer to the touch. However, various naturally occurring
lZ173(~
bentonites, such as Wyoming bentonite, which may be desirably
employed as a softening agent in detergent compositions,
tend to be off-color or of a tannish shade, and thereby ~ay
adversely affect the appearance of products containing it,
which eff~ct is more objectionable when the bentonite is
applied as a surface coating to detergent particles or
beads (because agglomeration appears to accentuate the
bentonite color and also because the color is not masked by
other constituents of the beads?. Also, bentonite, usually
being a very finely divided powder, may separate during
storage from other detergent composition particles of larger
siæe unless it i5 attached to them. By means of the present
invention such disadvantages of post-added bentonite are
overcome. Additionally, the invented products tend to cake
less than conventional detergent compositions, are of more
uniform appearance than products containing bentonite-
only agglomerates mixed with detergent beads, and are of bet-
ter bead strengths than products ~herein the clay is incorpor-
ated in the crutcher or post-added as a powder. Also, in one
aspect of the invention, flowability of the product is further
improved over corresponding products containing tacky materials
in the detergent ccm~osition formula.
In accordance with a product aspect of the
present invention, a particulate synthetic organic detergent
product comprises a ~mixture of 10 to 60~ of detergent composi-
tion particles having finely divided bentonite powder adhered
to external surfaces thereof and 90 to 40~ of detergent
composition particles devoid of such bentonite powder on the
surfaces thereof. In preferred embodiments of such invention
~2173~2
the detergent composition is in the form of spray dried
white beads, the bentonite is an off-white or tannish powder,
the bentonite comprises from 20 to 80~ of the beads of which
it is a surface portion and the bentonite is held to such
beads by a small proportion of sodium silicate binder. A
further preferred embodiment is one wherein the bentonite-
surfaced beads are higher in tacky synthetic organic detergent
content than the non-bentonite-surfaced beads. According to
the process aspect of the present invention a method of
manufacturing a particulate synthetic organic détergent
product comprises agglom2rating finely divided bentonite
powder and larger sized detergent composition particles so
that the bentonite powder adheres tc the external surfaces
of the detergent particles, and blending lO to60~ of said
bentonite-surfaced detergent composition particles with 90
to 40~ of non-bentonite-surfaced detergent composition
particles. In preferred embodiments of this inventive
aspect the bentonite powder is blended with spray dried
built synthetic organic detergent composition beads and is
agglomerated onto them by mixing while spraying a dilute
aqueous solution of sodium silicate onto the mix.
Such process is also useful for making deter-
gent compositions wherein all the detergent particles
have bentonite agglomerated onto them, as when the
bentonite is of excellent whiteness, off-color is not
~Z~73~iZ
objectionable, or the beads are dyed ox pigmented. In
accordance with this aspect of the invention a process for
manufacturing a fabric softening particulate synthetic
organic detergent composition comprises mixing together a
minor proportion of a finely divided bentonite powder and a
major proportion of larger sized detergent composition
particles, spraying onto the surfaces of the mixture, while
it is in motion, with new surfaces of the mixing materials
being continuously presented to the spray, a minor propor-
tion of an aqueous sodium silicate solution at a concentra-
tion in the range of 2 to 8~ in such quantity that the spray
deposits from about O.l to 0.4% of sodium silicate and about
2 to 8~ of moisture on the mixture, continuing mixing after
application of the aqueous sodium silicate solution, ~Ind
removing agglomerated particulate de1ergent with bentonite
powder held to the surfaces thereof. Preferably, the
bentonite employed i5 of particle sizes such that substan-
tially all of it passes through a No. 200 sieve, U.S. Sieve
Series (more p~eferably, all of it passes through a No. 325
sieve), the detergent composition particles are spray dried
particles of a built synthetic organic deter~ent composition
of particle sizes in the range of No's. 8 to lO0 sieves (more
preferably No's. lO to 60 sieves), the sodium silicate is of
Na2O:SiO2 ratio of about l:2.4, the droplets of the sodium
silicate spray are of diameters no greater than one milli-
i2173(~2
meter, (more preferably in the range of 0.1 to 0.5 mm.~,and the process takes place in a rotary drum type mixer,
such as one which extends longitudinally at an angle of from
about ~ to 15 to the horizontal, with the initial mixing,
the spraying-agglomerating and the subsequent mixing taking
place sequentially in an upstream third, a middle third, and
a downstream third of the mixer, respectively.
The present invention, including the process
thereof, will be readily unders.tood from the present specifi-
cation, taken in conjunction with the drawing, in which:
FIG. 1 is a schematic central longitudinal sectional
elevational view of a rotary drum type mixer, with other
equipment which may be utilized in the practice of a
process of this invention; and
FIG. 2 is a transverse sectional view of said
rotary drum along p.lane 2-2, showing the spraying of silicate
solution onto the tumbling particles of detergent composition
and bentonite.
The detergent composition particles which are the
base particles used in this invention, some of which may be
agglomerated with a more finely divided bentonite powder on
the surfaces thereof, may be any suitable particles and can
be produced in any of various ways. However, it will be
much preferred that they be spray dried particles of sizes
within the No's. 8 to 100, preferably 8 or 10 to 60 and more
1217~3~D2
preferably 10 to 40 or 60 sieve ranges,U.S. ~ieve Series.
Normally such products will comprise a synthetic organic
detergent which will be either an anionic or nonionic deter-
gent, a builder for the detergent, adjuvant(s) and moisture.
Among the vario~s anionic detergents that may be employed,
usually as their sodium salts, those which are most preferred
are linear higher alkyl benzene sul~onates, higher alkyl
sulfates and higher fatty alcohol polyethoxylate sulfates.
Preferably, in the higher alkyl benzene sulfonate the higher
alkyl is linear and averages 11 or 12 to 15 carbon atoms,
e.g., 12 or 13, and is a sodium salt. However, other alkyl
benzene sulfonates, of 10 or 12 to 18 carbon atoms in the
alkyl groups, may also be employed. The alkyl sulfate is
preferably a higher fatty alkyl sulfate of 10 to 18 carbon atoms,
preferably 12 to 16 carbon atoms, e.g~, 12, and is also employed
as the sodium salt. The higher alkyl ethoxamer sulfates will
similarly be o~ 10 or 12 to 18 carbon atoms, e.g., 12, in
the higher alkyl, which will preferably be a fatty alkyl,
and the ethoxy content will normally be from 3 to 30 ethoxy
groups per mol, preferably 3 or S to 20. Again, the sodium
salts are preferred. Thus, it will be seen that the alkyls
are preferably linear or fatty higher alkyls of 10 to 18
carbon atoms, the cation is preferably sodium, and when a
polyethoxy chain is present the sulfate is at the end thereof.
Other useful anionic detergents include the higher olefin
-- 7 -- ~
12~73~2
sulfonates and paraffin sulfonates, e.g., the sodium salts
wherein the olefin or paraffin groups are of 10 to 18 carbon
atoms. Specific examples of the preferred detergents are
sodium tridecyl benzene sulfonate, sodium dodecyl benzene sul-
fate, sod-um tallow alcohol polyethoxy (3 EtO) sulfate, and
sodium hydrogenated tallow alcohol sulfate. In addition to the
preferred anionic detergents mentioned, others of this well-
known group may also be present, especially in only minor propor-
tions with respect to those previously described. Also, mixtures
thereof may be employed and in some cases such mixtures can
be superior to single detergenl:s. The various anionic
detergents are well known in the art and are described at
length at pages 25 to 138 of the text Surface Active Agents
and Detergents, Vol. II, by Schwartz, Perry and Berch,
published in 1958 by Interscience Publishers, Inc.
Although various nonionic detergents of satisfactory
physical characteristics may be utilized, including condensation
products of ethylene oxide and propylene oxide with each
other and with hydroxyl-containing bases, such as nonyl phenol
and Oxo-type alcohols, it is highly prelerable that the nonionic
detergent, if present, be a condensation product of ethylene
oxide and higher fatty alcohol. In such products the higher
fatty alcohol is of 10 to 20 carbon atoms, preferably 12 to
16 carbon atoms, and the nonionic detergent contains from
about 3 to 20 or 30 ethylene oxide groups per mol, prefer-
ably from 6 to 12. Most preferably, the nonionic detergent
lZ1730Z
will be one in which the hi~her fatty alcohol is of about 12
to 13 or 15 carbon atoms and which contains from 6 to 7 or
11 mols of ethylene oxide. Such detergents are made b~
Shell Chemical Company and are available under the trade
names Neodol~ 23-6.5 and 25-7. Among their specially attrac-
tive properties, in addition to good detergency with respect
to oily marks on goods to be washed, is a comparatively low
melting point, which yet is appreciably above room temperature,
so that they may be sprayed onto base beads (which may contain
builders but usually little or no detergent) as a liquid
which solidifies. When nonionic detergents are utilized and
are applied to detergent beads as a spray, such spray may be
applied exclusively to the beads to be surface coated with
bentonite, or part of the nonionic detergent may be spray
dried with the builder salt and stable adjuvants. Alternative-
ly, and sometimes preferably (but this is rare) the nonionic
detergent may be sprayed onto the agglomerated bentonite-base
beads or onto a mixture of such beads with non-bentonite-
containing product.
The water soluble builder or mixture of builders
employed may be one or more of the conventional materials
that have been used as builders or suggested for such purpose.
These include inorganic and organic builders, and mixtures
thereof. Among the inorganic builders tnose of preference
are the various phosphates, preferably polyphosphates, e.g.,
tripolyphosphates and pyrophosphates, such as pentasodium
tripolyphosphate and tetrasodium pyrophosphate. Trisodium
nitrilotriacetate (NTA), preferably employed as the mononhydrate,
_ g _
~Z:173(~2
and other nitrilotriacetates, such as disodium nitrilotriacetate,
are preferred organic builder salts. Sodium tripolyphosphate,
sodium pyrophosphate and NTA may be utilized in hydrated or
anhydrous forms. Other water soluble builders that are
considered to be effective include the various other inorganic
and organic phosphates, borates, e.g., borax, citrates,
gluconates, EDTA and iminodiaceta~es. Preferably the various
water soluble builders will be in the forms of their alkali
metal salts, either the sodium or potassium salts, or a
mixture thereof, but sodium salts are normally more preferred.
The silicates,preferably sodium silicates of Na2O:SiO2
ratio within the range of 1:1.6 to 1:3.0, preferably 1:2 to
1:2.8, e.g., 1:2.35 or 1:2.4, also serve as water soluble
builder salts, but because of their strong binding properties
are useful to assist in agglomeration. The content of
silicate in the product will normally not exceed 10 or
15%, with the range of 5 to 15% being feasible, preferably
3 to 7 or 8% when zeolite is not present and 0 to 2 or 5%
in the presence of zeolite (with only small proportions of
silicate being employed as a binder to hold the bentonite
to the detergent or detergent base particles when zeolite
is present). In some cases it may be desirable to post-add
free flowing sodium silicate, such as hydrated sodium silicate
particles. In addition to the water soluble builders, water
insoluble builders, such as the zeolites, especially zeolite A,
preferably hydrated, e.g., containing 20% water, may be
substituted, preferably only partially.
-- 10 --
~2173(~;2
The bentonite employed is a colloidal clay (,aluminum
silicate) containing montmorillonite. The type of bentonite
clay which is most useful in making the invented base beads
is that which is known as sodium bentonite (or Wyoming or
western bentonite), which is normally a light to cream-col-
ored or tannish impalpable powder which, in water, forms a
colloidal suspension having strongly thixotropic properties.
In water the swelling capacity of such clay will usually be i~ a
range of 3 to 15 or 20 ml./gram, preferably 7 to 15 ml./g.,
and its viscosity, at a 6% concentration in watér, will
usually be in the range of 3 to 30 centipoises, preferably 8
to 30 centipoises. Prcferred swelling bentonites of this
type are sold under the trade mark Mineral Colloid, as indus-
trial bentonites, by Benton Clay Company, an affiliate of
Georgia Kaolin Co. These materials which are the same as,
those formerly sold under the trademark THIXO-JEL, are
selectively mined and beneficiated bentonite, and those
considered to be most useful are available as Mineral Colloid
No's. 101, etc., corresponding to THIXO-JELs No's. 1, 2, 3
and 4. Such materials have pH's (6~ concentration in water)
in the range of 8 to 9.4, maximum free moisture contents of
about 8% and specific gravities of about 2.6, and for the
pulverized grade about 85~ passes through a 200 mesh U.S.
Sieve Series sieve. ~eneficiated Wyoming bentonite is
preferred as a component of the present compositions but
-- 11 --
~217302
other bentonites including the synthetic bentonites (those
made from ~entonites having exchangeable calcium and/or
magnesium by sodium carbonate treatment) are also useful.
Also, the particle size may be lowered so that all of the
bentonite passes a No. 325 scxeen. Although it is desirable
to limit maximum free moisture content, as mentioned, it is
more important to make certain that the bentonite being
emp~oyed includes enough free moisture, most of which is
considered to be present between adjacent plates of the
bentonite, to facilitate quick disintegration of the bentonite
and any adjacent materials in the particles when such pa~ticles
or detergent compositions containing them are brought into
contact with water, such as wash water. It has been found
that at least about 2%, preferably at least 3% and more
preferably, about 4% or more of water should be present
in the bentonite initially, before it is admixed with
the other bead components in the crutcher, and such pro-
portion should also be present after spray drying or any
other drying that is undertaken. In other words, over-
drying to the point where the bentonite loses its "internal"moisture can significantly diminish the utility of the
present compositions. When the bentonite mois~.ire content
is too low the bentonite does not satisfactorily aid in
disintegrating the beads in the wash water. When the
bentonite is of satisfactory moisture content it may exhibit
an exchangeable calcium oxide percentage in the range of
- 12 -
12 IL73(}'2
about 1 to 1.8 and with respect to magnesium oxi~e such
percentage can be in the range of 0.04 to 0.41. Typical
chemical analyses of such materials are from 64.8 to 73.0%
of SiO2, 14 to 18~ of A12O3, 1.6 to 2.7~ of MgO~ 1-3 to
3.1% of CaO, 2.3 to 3.4% of Fe2O3, 0.8 to 2.8% of Na2O and
0.4 to 7.0% of K2O.
Although some adjuvants, such as fluorescent
brightener, pigment, e.g., ultramarine blue, titaniuin
dioxide, polyacrylate, and inorganic filler salt may be
added to the crutcher, others, such as perfumes, enzymes,
bleaches, some colorants, bactericides, fungicides, and flow
promoting agents may often be sprayed onto or otherwise
mixed with the base beads or spray dried detergent composi-
tions, with any nonionic detergent to be post-added, and/or
independently, so that they will not be adversely affected
by the elevated temperatures of the spray drying operation
and also so that their presence in the spray dried beads
does not inhihit absorption of nonionic detergent, when such
is to be post-sprayed onto the beads~ However, for stable
and normally solid adjuvants, mixing with the starting
slurry in the cr~tcher is also often feasible. Also, any
less stable adjuvants may be post-added to the agglomerate.
Of course, water is present in the crutcher to
serve as the medium for dispersing the various other bead
components, and some water, in both free and hydrate form,is
in the product. During drying of the beads the initial
- 13 -
12173~2
moisture content thereof, which will be about 25 to 60~,may
be lowered to about 5 to 15%, with such moisture content
being sufficient so that the bentonite in the dried beads
(normally less than 10% and preferably none is present)
contains at least 2% and preferably at least 4% of moisture.
It is prefered to employ deionized water, so that the hard-
ness ion contents thereof may be very low and so that metal~
lic ions that can promote decomposition of any organic
materials which may be present in the crutcher mix or post-
added materials are minimized, but city or tap water mayusually be employed instead. Normally the hardness content
of such water will be less than about 300 p.p.m., as CaCO3,
preferably less than 150 p.p.m.
The proportions of the various components in the
base beads ~nd in the spray dried detergent composition
beads will be such as to result in their being effective
cleaning agents, of acceptable flow properties, bulk density
and appearance. Preferably, in most cases, they will be
white, except that the beads coated with bentonite will often
appear darker in color (off-color) if examined closely.
If desired, a whitening agent may be employed, such as
Tio2 in an amount from 0.2 to 5% of the bentonite.
However, it is within the invention to utilize a coloring
dye or pigment in the crutcher mix so that the spray dried
beads (or beads otherwise produced) are colored.
It has been found tha-t satisfactory detergent composi-
tion beads can be made comprising 2 or 5 to 30 or 35%, preferably
S or 15 to 25 or 30%, e.g., 6 to 15% or 20 to 25%,of synthetic
organic detergent, preferably anionic detergent, 20 or 30 to 90%,
~2173~i2
preferably 30 or 35 to 80 or 85% and more preferably 35 or
45 to 70% of builder, 0.2 or 0.5 to 35 or 40~, preferably
0.5 or 1 to 20 or 30% and more preferably 1 to 10% or 1 to 20% of
adjuvant(s), and 3 to 20%, preferably 4 to 15% and more
preferably 5 to 12~ o5 moisture, e.g., 7 or 8~. 5uch beads,
which may be made by normal spray dr.~ing processes, or by
other "equivalent" means, will usually be of characteristic
globular or other shape known to result from spray drying,
often make ideal nuclei onto which bentonite powder may be
agglomerated. They will normally be of bulk densities
within the range of 0.2 to 0.7 g./cc., such as 0~3 to 0.5,
e.g., 0.35. The particle sizes thereof will normally be in
the 8 to 100 range and particles outside such range may be
removed by screening or other separating operations. More
preferably, the bead sizes will be from No. a or 10 to 40 or
60, U.S. Series, and the beads are white or of some other
color which would appear objectionably affected by application
of the commercial tannish or off-color bentonite particles to
the surfaces thereof, even if a color agent is applied with
it in an attempt to duplicate the original bead color. When the
beads containing bentonite on the surfaces thereof are to be
used directly, without blending with detergent beads, it is
preferred that they be white, not gray or tan, even if a
whitener such as TiO2 has to be used.
It has been found that when 10 to60%, by weight,
of the detergent composition particles have finely divided
bentonite powder agglomerated onto the surfaces thereof,
with 90 to 40% of the de'ergent composition particles being
devoid of such powder on the surfaces thereof, the hlman eye
- 15 -
lzl73a2
does not note the darkening of the bentonite-surfaced beads
and does not detect any objectionable speckling of the product,
at least not compared to products of similar composition in
which the bentonite powder is evenly distributed over the spray
dried beads, or in which bentonite-only agglomerates are used,
and so the invented products are not found to be objection
ably off-color by consumers. Preferred ranges are 20 to 50%
and 30 to 45%, e.g., 40%, for the bentonite surfaced material,
with the balance heing uncoated detergent composition particles.
The proportion of bentonite, by weight, on the surface of
the detergent beads on which it is coated, will normally be
with the range of 10 or 20 to 80%, preferably 35 to 65%, more
preferably 40 to 60%, e.g., 50% for the product to be blended
with bentonite-free detergent particles. For the agglomerated
particles to be used directly (no blending with detergent
particles) such ranges are 10 to 30%, preferably 15 to 25%,
e.g., 20% of the product. It is found that because
the spray dried beads are not solid, the applications of
these comparatively large quantities of bentonite do not
change the particle sizes dramatically, although there may be
some increase, such as about 5 to 15 or 30%, in bead diameters.
The relatively slight increase in the bead dimensions does
not create settling or "floating" problems and the presence
of the bentonite on the bead exterior appears to help inhibit
separations of different sized particles on storage (compared
to smooth surfaced, similarly non-tacky beads). Also, it does
not cause objectionable changes in product bulk density.
The application of the bentonite to the detergent
composition beads (which in some ca.ses may be inorganic builder
- 16 -
~Z173~2
beads, as when nonionic detergent is to be pos~-added) may
be effected by standard agglomeration techniques and equipment,
such as a rotary drum type mixer-agylomerator like that shown in
the drawing. One process that has been found to be especially
useful is to mix the desired weights of the detergent composition
beads and finely divided bentonite powder and while mixing, spray
water or more preferably,spray a dilute sodium silicate
solution onto the moving surfaces thereof. Such sprayings may
be at room témperature and will be gradual enough so as to
prevent any objectionable lumping of the mixture. Mixing
will continue in known manner until the bentonite powder is
all held to the detergent beads, after which mixing may be
halted and the product may be screened or otherwise size-
classified to be within the desired product size range. The
silicate solution employed when the agglomerate is to be mixed
with detergent particles will normally be at a concentration
of 0.05 to 10%, such as 0.2 to 6%, e.g., 1, 2 or 4~. Enough
will be employed so that on the beads on which it is present
it will constitute from 0.01 to 2%, such as 0.02 to 0.2 or 0.4
At such application concentrations satisfactory agglomeration
and surface coating are obtained, using suitable agglomerating
equipment, such as an O'Brien agglornerator, or a conventional
inclined drum equipped with spray nozzles, baffles, etc. Also,
the moisture sprayed onto the beads is not excessive, usually
being about 1 to 10% of the bead weight, e.g., 2 to 5%, which
will be less on the basis of the final product. The product
resulting is sufficiently firm to be able to withstand
handling, packaging and storage without objectionable powder-
ing and loss of the bentonite coating. Also, the silicate
lZ173C~2
concentration is not so high as to inhibi~ dispersion of the
bentonite in the wash water when the produ~t is employed in
laundry operations. Although it is preferred tha~ silicate
be employed in the agglomerating spray, useful product is
obtainable by utilizing water alone as an agglomerating
agent or by employing aqueous solutions of other binders,
such as gums~ resins, surface active agents (detergents),
but in the absence of such material the bentonite, which has
binding properties, will normally be cohesive enough to make
coated particles of desired physical stability, which will
rapidly disperse in the wash water. If desired, a dye may
be applied in the liquid spray utilized in agglomeration, so
as to color the resulting particles. Normally the dye
concentration will be less than 1~ of the liquid being
sprayed, e.g., 0.01 to 0.1~ thereof. By employing the dye
for only tha bentonite surfaced particles the resulting
detergent product will have an attractive appearance and the
"softener particles" will be dye-identified. If it is de-
sired to have the product all colored (and blue is a ~re-
ferred color), the base beads may also be colored. Specif-
ically, ultramarine blue pigment may be crutched in w th the
other components of the spray dried detergent composition and
Acilan blue or Polar Brilliant blue (dyes) may be sprayed onto
the surfaces of the agglomerated bentonite particles.
In a variation of the present invention, the
flowability of the resulting product can be improved by
incorporating some or all of the most tacky components of
the final product in the beads to be bentonite-surfaced.
Then, such beads are coated with a protective film of
- 18 -
~2~73~Z
agglomerated finely divided bentonite particles and the
tacky component is buried below the bentonite surface, thus
being ineffective to inhjbit free flow. The other particles
of the detergent, not containing such component, flow more
freely than wsuld be the case if it was included in their
composition, too. Additionally, the tacky material may act
to promote agglomeration of the bentonite and the firm
holding thereof to the surfaces of the base particles. In
fact, in another version of the invention some or all of the
synthetic organic detergent, either an aqueous solution of
anionic detergent or a liquid state nonionic detergent, is
sprayed onto the detergent composition base particles before
mixing thereof with the bentonite. This post-spraying of
the detergent, rather than incorporating it (or some of it)
in the crutcher and spray drying it, improves the spray
drying operation and increases spray tower throughput rates.
Of course, in situations where flowability is not a problem
and where relatively large proportions of nonionic detergent
are to be post-sprayed onto the detergent composition base
bead surfaces,it may not be necessary or desirable to apply
all the detergent or more than a pro rata share of it to the
bentonite-surfaced beads but where flowability is unsatisfac-
tory this aspect of the present invention provides means for
improving it significantly. When at least a part of the
synthetic organic detergent is to be spray dried in the base
beads then normally the beads to be coated with bentonite
will have at least 10%, preferably 25% and more preferably
50% more of detergent than the rest of the beads.
-- 19 --
12~73~2
After the bentonite-surfaced beads are produced
they may subsequently be mixed with materials to be post-
added or such materials may ~e sprayed onto the bead surfaces
but normally the bentonite-surfaced beads will first be
mixed with the halance of the spray dried detergent composi-
tion material, after which any post-added material may be
applied or mixed with them. Among such materials are enzyme
powders, bleaches and perfumes. Alternatively, some of said
materials may be applied to or mixed with the different
beads or to or with some of them before the hentonite-
surfaced beads and the other beads are mixed together. It
is also possible to post-add some of the adjuvants to the
detergent beads before application of the bentonite to such
beads but such method is not usually practiced. After
mixing togethex of the different portions of the present
compositions, they may be stored for a curing period of one
to twenty-four hoùrs, for example, but usually there will not be
any need for such a cure,and they may then be mixed with any
adjuvants, unless such was accomplished earlier. They may
then be transported to packaging equipment, and may be packed,
cased, stored and/or shipped.
The products resulting from this invention, as previously
described, when detergent composition beads are white, will appear
noticeably whiter than corresponding products in which the bentonite
to be applied is distributed evenly over all the particles.
This phenomenon appears to depend on the proportions of the
beads, and to some extent, on the particle sizes thereof.
Also of importance is that the invented products do not
appear speckled although they do contain white ~nd tannish
particles. Yet, they appear uniform and are light of color.
When lesser proportion~ of bentonite-surfaced particles than
- 20 -
lZ173~2
the lower limit of the broadest range specified herein areemployed, while the darker color of such particles may not be
objectionably noticeable, the bentonite content of the
product will usually be less than desirable. When a greater
proportion o~ bentonite-surfaced particles than the upper
limit of the broadest range given are employed the product
will be noticeably darker and off-color and its appearance
will be objectionable to the average consumer, making it
difficult to market. Specific reflectance differences are
not given herein because of the varying natures of the
natural and synthetic bentonites available commercially and
their different shades, but differences are noticeable by
use a reflectometer, such as a Hunter reflectometer, or by
use of a spectrophotometer, such as one made by C~neral
Electric Company. IIowever, it is usually not necessary to
employ instrumentation to detect the differences in color
because these arP so readily apparent to the eye of the
average consumer. When different percentages of deterqent
are present in the bentonite-surfaced and non-bentonite-
surfaced beads, as previously taught, and when detergent isapplied to the beads to be coated with bentonite,improvements
in product flowability are noted and the products resulting
are noticeably less tacky to the touch and tend less to
clump in the box on storaqe. Such improvements in these
2S properties are verifiable by standard tests employed in the
detergent industry, such as flow-time, angle-of-repose and
compaction tests.
As will be evident, the properties of the final
detergent product are improved without need for adjuvants
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lZ173~;Z
to improve color, flow or non-tackiness. Thus, the expenses
of such adjuvants and their sometimes undesirable other
properties are avoided. Because only a portion of the
detergent beads is subjected to agglomeration, throughput
5 times for the agglomerating equipment are diminished. Thus,
both composition and process advantages are obtained and the
final product is surprisingly improved, compared to one
containing the same total proportion of bentonite coating
all the detergent composition particles.
The following examples illustrate but do not limit
the aspects of the invention that have been described in detail.
Unless otherwise indicated all parts are by weight and all
temperatures are in C.
_XAMPLE 1
Percent
Sodium linear tridecylbenzene sulfonate 12
Pentasodium tripolyphosphate, hydrated 34
Sodium silicate (Na2O:SiO2 = 1:2.4) 7
Sodium sulfate 12
Borax 2
Sodium carboxymethyl cellulose 0.5
Bentonite (Mineral Colloid 101, 200 20
mesh, 7~ H2O)
Perfume O . S
Moisture 12.0
100. 00
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121730Z
A detergent composition of the above formula is
made by spray drying a mixture of the components of such
composition, except for the bentonite and perfume (and with
slightly less silicate, to allow for that post-added), at a
crutcher mix moisture content of about 35~ in a standard
commercial countercurrent spray d~^ying tower under normal
conditions, with the drying air temperature in the ran~e of
200 to 400C., to produce globular beads of normal particle
size distribution in the range of No's. 10 to 100, U.S.
Sieve Series. One part of such beads is transferred to an
O'Brien agglomerator or similar agglomerating apparatus and
is mixed therein with an equal weight of the bentonite,
and while mixing is continued there is sprayed onto the
moving surfaces of the particles an aqueous solution (at room
temperature containing 5% of sodium silicate, with the total
proportion of spray applied being about 0.04 part. Agglom-
erating is continued for about 20 minutes, during which time
some moisture evaporates, and after which substantially all
the particles are in the 8 to 100 sieve si e range. Particles
outside this range are removed and 1.5 times the weight of
the remaining particles (omitting added water) of the spray
dried detergent beads, devoid of bentonite coating, are then
blended with the bentonite-surfaced beads in a tumbling drum
for a period of twenty minutes, after which the product is
2~ perfumed and packed in cartons. The spray dried detergent em-
oyed herein has a moisture content of about 8 to 10% but
this can be changed by using beads and bentonite of other
moisture contents and varying the spray accordingly. The product
_ 23 ~
lZ173(~;2
made, when it is compared with a control product, made in
similar manner but with the bentonite being coated onto all
the detergent particles (with the total proportion of benton-
ite being the same as in the final product of the invention),
appears lighter in colo~, uniform in appearance (not "spotty"),
and more attractive to the human eye, making it more acceptable
to the consumer. To make a colored product 0.2~ of ultramarine
blue pigment may be in th~ spray dried beads, with 0.004% of
Acilan blue being on the bentonite agglomerates to match color.
When silicate is omitted from the agglomerating spray a satis-
factory product can also be made but upon aging such a product
may be significantly more friable.
When the above described procedures are varied by
blending 0.3 part of enzyme powder (Alcalase ,2 Anton units
per gram) in prilled or powder form (prills within the 10 to
100 mesh range and powder through 200 mesh) before perfuming,
the improvement in the appearance of the product is still
evident.
The various products of this example are all
satisfactory fabric softening particulate detergents, useful
in automatic washing machines for heavy duty washing of
soiled laundry.
EXAMPLE 2
A product of the formula of that of ~xample 1 is
made by spray drying two different compositions, one containing
24~ of sodium linear tridecylbenzene sulfonate and the other
containing 12~ thereof. The difference is made up by decreasing
or increasing the sodium sulfate contentsof the respective
formulas. The product higher in anionic detergent content
* a trade mark
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~2~73(3 Z
(and lower in sulfate) is tackier to the touch and it is
this product which is coated with an equal weight of bentonite
powder (throu~h a No. 325 sieve) and which is subsequently
blended with 1.5 times the weight of the resulting agglom-
erate (which is agglomera~ed in the same way as in Example1) of the non-bentonite-surfaced beads, ~hich are lower in
anionic detergent content. The mixture is then perfumed in
the normal manner.
The product resulting is of improved flowability
compared to the product of Example 1, apparently due to the
"insulating" effect of the bentonite particles agglomerated
onto the surfaces of the beads higher in anionic detergent
content. Also, due to the tackiness of such beads, the
amount of silicate solution applied may be reduced, sometimes
to half that employed in Example 1. In addition to making
a product which is more free flowing, less tacky and less
susceptible to caking on storage than the products of Example
1 (which products are acceptable for commercial purposes),
the presence of the greater proportion of anionic detergent
in the bentonite-containing beads promotes more rapid
disintegration and dispersion of such beads in the wash water,
which improving is aided by the presence of a lesser propor-
tion of silicate in the surfacing bentonite matcrial. In
some instances, as in Example 1, the silicate may be omitted
fxom the agglomerating spray or equal proportions of other
binding materials, such as sodium polyacrylate, polyvinyl
pyrollidone or hydroxypropylmethyl cellulose may be substituted.
An additional advantage of the process of this example is that
bentonite fines, sometimes present with the bentonite agglome-
rate, are reduced, attributable to the tacky detergent, in part.
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1;~173~
~XAMPLE 3
The procedure o~ Example 1 is varied by decreasing
the anionic detergent content of the spray dried beads from
15% to 14~ and spraying the remaining anionic detergent onto
the surface of the portion of the beads to be coated with
bentonite particles, and in the agglomerating spray. The
sprayed material is of a solids concentration of about 10
in water and if the product made becomes too sticky, heat
and air flow may be employed to lower the moisture content
to reduce such stickiness to an acceptable "tacky" level.
The detergent composition resulting, after mixing of the
bentonite-surfaced beads with the non-bentonite-surfaced
beads, is of properties comparable to that of Example 2.
EXAMPLE ~
15 When the sodium linear tridecylbenzene sulfonate
of Example 1 is replaced by sodium hydrogenated tallow
alcohol polyethoxy (3 EtO) sulfate, sodium hydrogenated
tallow alcohol sulfate, sodium paraffin sulfonate or sodium
olefin sulfonate of 16 carbon atoms in the paraffin and
olefin groups, or by any two-component mixtures thereof (of
equal parts) products comparable in properties to those of
Example 1 are obtained. This is also the case when the total
of the penta~odium tripolyphosphate and sodium sulfate
contents is replaced by pentasodium tripolyphosphate, sodium
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lZ173~2
carbonate, sodium bicarbonate, zeolite A or equal part two
component mixtures thereof. Also, when the proportion of
bentonite applied to the bentonite-surfaced beads is varied
to 15 and 25~ acceptable products of improv~d appearance are
obtained, which is also the case when the proportion of
bentonite-surfaced particles is changed to 15 and 25~,
respectively.
EXA~lPLE 5
Percentages
Sodium carbonate 22
Sodium bicarbonate 16
Zeolite A, hydrated (20~ moisture) 32
Fluorescent Brightener (Tinopal ) 1.5
Moisture 9.o
Perfume 0 5
Nonionic detergent (Meodol 23-6.5) 19
100. 00
Decergent beads of the above composition are made
by spray drying from a 60~ solids crutcher mixture beads of
the indicated particle sizes comprising all the described
constituents except the perfume and nonionic detergent,
which are post-sprayed onto such moving bead surfaces
(although preferably perfume is applied to the bentonite-
containing beads after agglomeration). Due to the content
* a trade mark
- 27 -
~lZ1730Z
of ~eolite A the nonionic detergent is satisfactorily
absorbed. Then, one part o~ such composition is surface-
agglomerated with one part of bentonite powder (-325 mesh)
which appears tannish after coating such particles. After
the agglomeration is completed l-1/2 parts of non-bentonite~
containing detergent composition bea~ are blended with the
bentonite-surfacedproduct. The final product is an excellent
softening detergent of the heavy duty nonionic built detergen~
type and is of whiter appearance than a control wherein the
bentonite is surface agglomerated onto all the particles (at
the same total concentration of bentonite). The product is
a satisfactory heavy duty laundry detergent.
In a modification of this invention a small proportion,
0.1%, of blue dye (Acilan blue), in the silicate solution,is
sprayed onto the surfaces of the particles in the agglomerator
to color such particles.
When variatiGns are made in the manufacturing
method whereby more nonionic detergent, e.g., 1/lO to l/4 more,
is sprayed onto the beads to be coated with bentonite than
onto the beads not to be so coated, flowability is improved
and the product made is less tacky.
The foregoing description relates primarily to
the aspectsof this invention which involve making a fabric
softening detergent product of improved co]or (or appearance)
and flowability. Now the making of a detergent composition
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~21730Z
in which bentonite is agglomerated onto detergent particles
will be described in more detail. It will be understood
that the resulting composition may be blended with detergent
composition particles or may be used without such blending.
In FIG. 1 an open ended, inclined, cylindrical rotary
drum 11 is shown rotating about an axis which is at a
relatively small acute angle to the horizontal, with such
rotation being in the direction shown by arrows 13 and 15.
Drum 11 rests on rollers 17, 19 and 21, which rotate in the
opposite direction from the drum (counterclockwise, rather
than clockwise, viewed from the left), causing it to turn as
indicated. Rotary drum 11 contains a mixture 23 of spray
dried built synthetic crganic detergent beads and bentonite
powder which is agglomerated in the drum into fabric softening
detergent composition beads or particles, due to the spraying
of a dilute sodium silicate solution onto the particles
while the mixture is in motion. Final agglomerated softening
detergent particles 25 are removed from drum 11 via shute
27. Spray nozzles 29, 31 and 33 are employed to produce essen-
tially conical sprays of silicate solution, such as thoserepresented by numera~ 35, which impinge on the moving
mixture of detergent beads and bentonite powder and promote
agglomeration of the powder onto the surfaces of the beads
although in some instances agglomerates may also be formed
o~ bentonite alone or detergent beads alone tthe latter
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~2~73~Z
being less common). In the rotating drum, the right or
upstream third or similar part is a mixing zone wherein the
bentonite and detergent beads are dry mixed, the middle
portion is a spraying and agglomerating zone, and the down-
stream third or so is one wherein spraying i~ not effected,the moistened particles and agglomerates are "finished" to
relatively free flowing product, and the desired form and
character of the agglomerate results.
The foregoing description relates primarily to a rotary
drum which is a preferred embodiment of the apparatus employed in
the practice of this aspect of the invention although other
equivalent or substitute means may also be utilized. In
addition to the rotary drum, supply means for adding the
various final product constituents are provided. Thus,
supply tank 37 contains sodium silicate solution 39 (as
distinguished from spray 35), which is delivered to spray
nozzles 29, 31 and 33 through line 41. Hopper bin 43 contains
detergent beads 45 which are delivered to hopper 47 by means
of delivery belt 49. Similarly, hopper bin 51 contains
bentonite powder 53 which is delivered to hopper 47 by
delivery belt 55. Arrows 57 and 59 indicate the directions
of such belt movements, respectively.
~ In FIG. 2 the mixture 23 in drum 11 is shown being
carried up the left wall of the drum, which is rotating in
the direction of arrow 13. As mix 23 falls downwardly along
- 30 -
~Zi~3~)2
the face 61 of the upper wall thereof spray 35 of aqueous
silicate solution, sprayed in conical patterns from nozzle
29 and other hidden nozzl~s 31 and 33,impinges on the moving
mixture,moistens the surfaces of the nucleus detergent compo-
sition beads and promotes agglomeration o~ the bentonitewith the bead_, with t'ne more finely divided bentonite
powder usually adhering to the surfaces of the larger detergent
composition particles. Thus, constantly renewing faces Ol-
curtains of falling particles are contacted by the sprays
and substantially uniform moistening and application o the
silicate to the particles is obtained, which leads tG produc-
tion of a ~lore uniform and better agglomerated product.
The detergent composition particles, bentonite,
silicate, adjuvants, etc. employed in the agglomeration process
~ust described are those previously recited in this specification.
When the agglomerated detergent particles, with
bentonite on the surfaces thereof, are to be used directly a
silicate solution will preferably be used to bind the bentonite
to the detergent particles. While the solution concentrations
and proportions previously mentioned may be used usually the
silicate solution concentration will be 2 to 8%, preferably 3 to
7% and more preferably 3 to 6%, e.g., 4% and 5%. Enough will be
employed so that on the beads on which it is present the silicate
from the spray will constitute from 0.1 to 0.4%, preferably
0.2 to 0.3~ of the final product weight. At such application
concentrations and amounts satisfactory agglomeration and
surface coating are obtained, using the rotary drum Gr other
lZ1~3(1 2
suitable agglomerating equipment. Also, the moisture sprayed
onto the beads is not excessive, usually being about 3 to 6~
of the product weight. Allowance can be made for this added
mois~ure by making the detergent composition beads drier by
a corre5p~nding amount.
As with the previously described products, that
which results is suf~iciently firm to be able to
withstand handling, packaging and storage without objec-
tionable powdering and loss of the bentonite coating.
Also, the silicate concentration is not so high as to inhibît
dispersion of the bentonite in the wash water when ~he product
is employed in laundry operations. If desired, a dye may be
applied in the liquid spray utilized for agglomeration, so
as to color the resulting particles. Normally the dye concen-
tration will be less than 1% of the liquid being sprayed, e.g.,0.01 to 0.1% thereof.
After the bentonite-surfaced beads are produced
they may subsequently be mixed with materials to be post-
added or such materials may be sprayed onto the bead surfaces.
Among such materials are enzyme powders, bleaches and perfumes.
Alternatively, some of said materials may b~ applied to or
mixed with the base beads or the bentonite before agglomeration.
After agglomeration is completed the products may be stored for
a curing period of one to twenty-four hours, for example, but
usually there will not be any need for such a cure, and the
agglomerates may be mixed directly with any adjuvants, unless
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~Z~73(~2
such was accomplished earlier. The agglomerated beads made are good
detergents possessing significant softening properties. They
are also free flowing, non-dusting and substantially non-
friable, and possess good bead strengths and abrasion resistances.
The following examples additionally illustrate the
invention~
EXAMPLE 6
A crutcher slurry is made comprising 1,009 parts
of water, 2,584 parts of a detergent base (about 37~ active
ingredient and about 20% of sodium sulfate, with the balance
being water), 841 parts of sodium silicate (Na20:SiO2 =
1:2.4), 1,315 parts of pentasodium tripolyphosphate, 542
parts of soda ash, 24 parts of sodium sulfate and 293 parts
of an aqueous solution of fluorescent brightener, anti-
redeposition agent, stabilizer, and other minor components
in dilute aqueous solution. Crutching is in a commercial
plant detergent crutcher at a temperature of about 55C. for
a period of about ten minutes after addition of all the
components, with the solids content of the crutcher mix
being adjusted to!about 58C. during the crutching. The
cr-utcher mix~ i$~subsequently pumped to a countercurrent
spray drying tower wherein it is forced through eight nozzles
of the 10/10 type at a temperature of 52C. under a pressure
of about 24 kg./sq. cm. The tower temperatures are: Tl =
410C. and T2 = 120C. The detergent beads produced are at
a moisture content of about 7~ and the spray rate is about
9,000 kg./hr. The beads made are screened to be in a size range
of 10 to 60, U.S. Sieve Series. The beads are white and are
- 33 -
~17302
of a bulk density of about 0.3 g./ml.
Equipment essentially like that illustrated in
FIG'S. 1 and 2 is employed to agglomerate finely divided
bentonite onto the surfaces of t,he described spray dried
-detergent composition beads. To make the desired approximately
20% ben~onite produc~ No. 325 sieve bentonite powder (contain-
ing about 5% of moisture) is mixed with the detergent composition
beads in a proportion of 76. 4 parts of the base beads to
19.2 parts of the bentonite. 3.8 Parts of a 5~ sodium
silicate solution (Na2O:SiO2 = 1:2.4) are sprayed onto the
tumbling mixture in the rotary drum agglomerator-mixer,
utilizing a spray lance having six nozzles (three are illus-
trated in the drawing) spaced apart about 1/2 meter. The
spray pressure is about 5 kg./sq. cm., which produces a
misty spray in which the individual droplets are of diameters
within the range of about 0.1 to 0.5 mm. (weight average).
After about eight minutes total mixing in the rotary drum,
which is at an angle of about 7,with about the last third
of the drum being free of silicate spray application, the
product is continuous~y removed, after which it is perfumed
with 0.2 part of a suitable perfume and has 0.4 part of
enzyme powder blended with it. In a variation of the process
the enzyme may be bIended with the product in the tumbling
drum, in the last third thereof, with or without perfume.
The product resulting is an especially useful
fabric softening particulate detergent, which may be screened,
if desirable, so as to be in the No's. 10 to ~0 range or the
8 ~o 100 sieve range, as desired. The bulk density of the
product is about 0.35 or 0.4 g./ml. and it comprises about
- 34 -
lZ1730Z
18% of sodium dodecyl be~zene sulfonate, 25% of sodium
polyphosphate, 9.5~ of sodium silicate, 9~ of soda ash, 10%
of sodium sulfa~e, lg~ of bentonite, 0.4% of enzyme powder,
0.2~ of perfume, 0.1% of fluorescent brightener and 9% of
water. The detergent beads are free flowing, non-tacky,
sufficiently strong for commercial marketing, readily dispers-
able in wash water and attractive in appearance. In short,
the product is an excellent fabric softening heavy duty
particulate laundry detergent.
EXAMPLE 7
The procedure of Example 6 is followed except that
the silicate solution applied is 3% of sodium silicate and
the proportion of solution applied is 4% of the total final
product. Flowability, bead strength, non-friability and
abrasion resistance are satisfactory, like that of the
product of Example 6, and the product is a satisfactory
heavy duty fabric softening detergent composition. Similarly,
when the same proportion of 6~ sodium silica~e solution is
utilized good results are also obtained. However, when the
silicate solution is at 10% concentration the product is less
satisfactory, being lumpy in appearance. When only water
is employed as the spray an agglomerate is obtainable but it
tends to be higher Ln fines and generally less satisfactory
than those agglomerates which are made using the sodium
silicate solution at 2 to 8% concentration. From these
- 35 -
~Z~73~Z
experim~nts and others in which the proportion of silicate solu-
tion spray is varied it is concluded that better products are
obtained when the proportion of spray is about 2 to 8% ~moisture
basis) of the product ~nd the silicate deposited in the
spray is from 0.1 to 0.4% of such product.
EXAMPLE 8
The procedure of Example 6 is varied by omitting
the soda ash from the crutcher mix and replacing it with
sodium sul~ate. Also, modifications may be made in the
location of the spray nozzles in the agglomerating rotary
drum, so that the bentonite and detergent composition beads
are mixed in the first quarter of the drum, spraying takes
place in the middle half, and subsequent mixing takes place
in the end quarter. The product resulting is also a s~tisfac-
tory fabric softening particulate heavy duty detergent likethoRe of Examples 6 and 7. When a blue dye, such as Polar
Brilllant blue, iR present at a concentration of 0.2~ in the
silicate spray solution (or from 0.01 to 0.4%) attractively
colored product results. Ultramarine blue and other pigments
may be substituted for the dye or may be used with it.
EXAMPLE 9
Chal~ges in the crutcher mix formulations, temperatures,
mixing times and mixing procedures are made and different spray
drying tower conditions are employed to produce the detergent
25 composition base beads. Variations of +lO~ and i20~ are made
in the different formula ingredients of Examples 6-8 and in
- 36 -
lZ1730;~
the mixing times, nozzle pressures and other conditicns (but
such variations are kept within the described ranges) and a
good base bead is made, having a bulk density in the range
of 0.3 to 0.5. Also, changes are made in the nozzle designs,
pressures and silicate concentrations for the spray solutions,
as previously described, and so long as the silicate concentra-
tion, amount of solution applied and silicate deposited with
the bentonite on the base beads are within the ranges previously
given good products result. Such is also the case when the
concentration of bentonite in the final product agglomerate
is varied within the range of 15 to 25~. Also, similar
results are obtainable when the detergent beads agglomerated
with bentonite are nonionic detergents made by spraying
nonionic detergent in liquid state onto base inorganic
builder beads, after which agglomeration with bentonite and
aqueous sodium silicate solution is effected.
Good products are also obtained when instead of
employing the very finely divided bentonite (through No. 325
sieve), such as the Thixo-Jel No. 1 (Mineral Colloid No.
1,001) used for these examples, other bentonites axe used,
such as those prGduced by American Colloid Company and those
made from European and other bentonites having exchangeable
calcium and/or magnesium ions therein converted to sodium ions
by sodium carbonate treatment.
The invention has been described with respect to
illustrations and examples thereof but is not to be limited
to these because it is evident that substitutes and equivalents
may be employed without departing from the invention.
* a trade mark
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