Note: Descriptions are shown in the official language in which they were submitted.
03~76
This invention relates to a process for manufacturing a
low density, particulate, built synthetic organic detergent com-
position. More particularly, it relates to the inclusion of a
small proportion of an organic hydrotropic salt in a crutcher mix
before spray drying a substantially inorganic particulate base com-
position onto which nonionic detergent is subsequently coated. It
has been found that the presence of the hydrotrope in the crutcher
mix results in production of substantially lower density base and
final detergent composition particles. Also with the invention
are a method for manufacturing such low density base particles,
plus particulate base and built synthetic organic detergent com-
positions which may be made by such methods.
Recently, built particulate synthetic organic detergents
based on nonionic detergents have been found to posses various
advantages over the previously conventional heavy duty, built,
particulate anionic synthetic organic detergents. However, when
manufacture of the built nonionic detergent compositions was under-
taken by methods previously used for producing such counterparts,
such as by spray drying the final composition from a crutcher mix,
various problems were encountered. The most objectionable of these
was the fuming of the nonionic detergent during the spray drying
process, causing objectionable smoke from the spray drying plant
and resulting in the loss of the detergent. In addition to being
objectionable from the environmental standpoint the process is more
costly and results in the production of detergent composition part-
icles o widely varying active
c~,
11003~76
ingredient (nonionic detergent) content, depending on spray
tower conditions. Accordingly, post-addition of most or all
of the nonionic detergent has been suggested and commercial
products have been made by such method as disclosed in
United States patents 3,838,072; 3,849,327; 3,886,098;
and 3,971,726; and German Offenlegungsschrift 2,514,677.
Although post-addition of the nonionic detergent,
usually b~ spraying a melt thereof onto the surfaces of
moving particles of a base composition, which is usually
substantially inorganic and constituents the remainder of the
detergent composition or st of the remainder thereof,
results in a useful product, generally such product will be
of a higher bulk density than that previously produced when
anionic detergents (including soaps) were present in the
crutcher mix. In some instances the higher density particles
are acceptable and even desirable but in many cases it is
important to produce low bulk density products, such as those
to which the consumer has previously been accustomed, the
bulk densities of which are usually in the 0.3 to 0.5
g./cc. range. It has been found that when a substantially
inorganic crutcher mix is spray dried the beads produced
thereby, after nonionic detergent addition, will be of a
~igher density than desired, such densities often being in
the 0.55 to 0.75 g./cc. range. When nonionic detergent is
1100376
post-sprayed or otherwise coated onto the base composition part-
icles the densities thereof are increased slightly or sometimes may
remain about the same. Thus, so as to be able to produce a commer-
cial built heavy duty nonionic detergent product, efforts have been
made to decrease the bulk density of the spray dried beads of the
base composition and to make a low density particulate detergent
from such base particles.
The use of soap and other anionic detergents, in small
quantities, as constituents of an essentially inorganic crutcher
mix has been found to lower the bulk density of the dried particles
resulting from spray drying. Such effects are described in United
States patent 3,971,726 and in the German Offenlegungsschrift pre-
viously mentioned. However, the use of such detersive products,
even in comparatively small proportions, may promote foaming, which
is often undesirable for particular detergent compositions.
Furthermore, with the use of small quantities of anionic detergents,
as described in the German Offenlegungsschrift, certain specific
operating conditions may have to be maintained in the spray tower
and in some cases only particular compositions will be capable of
being produced in the desired low bulk density range. Such un-
desirable properties in the product and such restrictions on the
compositions and methods employed may be obviated by the present
processes and satisfactory compositions may be made, utilizing them.
~i
': llU~376
In accordance with the present invention there is
provided a process for manufacturing a low density, particulate,
built synthetic organic detergent composition which comprises
mixing together a plurality of components of a crutcher mix
comprising inorganic builder salt(s) selected from the group
consisting of water soluble polyphosphates, carbonates,
silicates, borates, bicarbonates, and phosphates, water soluble
organic hydrotropic salt(s) and water in such proportions that
when subsequently dried the water soluble organic hydrotropic
salt(s) present significantly reduces the density of the product,
drying the mix and applying onto the surfaces of particles of
the dried mix a detersive proportion of nonionic detergent.
The inorganic builder(s) may be sodium tripoly-
phosphate, sodium silicate and sodium carbonate, often with
inorganic filler salt~s), such as sodium sulfate. The water
soluble organic hydrotropic salt(s) may be sodium toluene
sulfonate and/or sodium xylene sulfonate. The water is usually
present to the extent of 0.2 to 5% in the crutcher mix and
preferably 1.2 to 2% in the final product. The density of
the product is significantly reduced (to 0.25 or 0.3 to 0.45
or 0.5 g./cc. [0.25 to 0.45 g./cc. in the base composition
particles]~. The detergent is normally applied to the surfaces
of particles of the dried mix by spraying in an amount, of
usually 5 to 17% and preferably 7 to 15~. Preferably the
nonionic detergent is higher fatty alcohol polyethylene oxide
condensate. Also, within the invention are a process for ma~ing
the base Co~pofiition particles to be spray treated and preferred
base and final detergent compositions.
The base detergent composition, sometimes referred
to as the carrier composition, will usually be composed
substantially of inorganic materials, primarily inorganic
B _5_
110(~!376
builder(s) and preferably also inorganic filler salt(s). However,
it may also contain other desirable constituents of the final
detergent composition, except the nonionic detergent, which are
sufficiently heat stable to withstand a drying operation, such as
conventional spray drying. Preferably, any anti-redeposition
agent, such as sodium carboxymethyl cellulose, and any quantity of
sodium silicate in excess of about 15%, preferably 10%, on a base
composition basis, will be post-added, before, after or with the
nonionic detergent, preferably as particulate solids. If desired,
flow promoting clays such as that sold under the trademark
Satintone, may also be post-added but use thereof is not normally
needed for the manufacture of a sufficiently free flowing, non-
tacky and non-caking product. Colorants, perfumes, fluorescent
brighteners, fungicides, herbicides and other adjuvants may also be
post-added and when sufficiently soluble, may be dispersed or dis-
solved in the nonionic detergent and applied to the base particles
with it, as by spraying.
The builder components of the present compositions are
preferably water soluble polyphosphates, carbonates, silicates,
borates, bicarbonates and phosphates, usually as the sodium or
potassium salts, e.g., pentasodium tripolyphosphate, tetrapotassium
pyrophosphate, sodium carbonate, potassium bicarbonate, sodium
silicate (Na20:SiO2 = 1:2.35), borax and disodium hydrogen phos-
phate, but it is contemplated that organic builder salts may also
be employed, at least in
X
~IU0376
partial replacement of the inorganic builders. Such replacement
may also be made with water insoluble builders such as the
sodium aluminosilicates preferably zeolites of Types A or X,
crystalline or amorphous, various examples of which are
disclosed in United States Patent 2,882,243; Belgian Patents
813,581 and 835,351; German Offenlegungsschriften 2,412,837 and
2,412,839; and Austrian Patent Applications A 4484/73;
A 4642/73; A 4666/73; A 4717/73; A 4750/73; A 4767/73;
A 4787/73; A 4788/73; A 4816/73; and A 4888/73. Additionally,
such insoluble builders are described in the text Zeolite
Molecular Sieves by Donald ~. Breck, published in 1974 by
John Wiley & Sons, specifically being listed in Table 9.6 at
pages 747-749 thereof. Of the builders present normally at
least 50% will be ~ater soluble inorganic builder salts.
Preferably, this proportion will be at least 80%, more
preferably, at least 9a% and most preferably, 100~. Although
it is not necessary to incorporate a filler salt in the base
beads or in the final detergent composition generally the
presence of such material will be desirable. Among the best
of the fillers, contributing particle strength, stability and
flowability at relatively little cost, is sodium sulfate,
which will u~ually be substantially all or all of the filler
present, usuall~ heing over 50~ and preferably over 90% of the
filler content.
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1100376
However, other water soluble and non-deliquescent inorganic salts
which are heat stable may also be employed, such as sodium chloride,
sometimes found as an impurity in one of the product components,
potassium sulfate, sodium bisulfate and potassium chloride.
The hydrotropic salt, which has been found to aid in the
manufacture of the low density carrier particles of this invention,
may be any such compound which has the property of promoting water
solubility of only slightly soluble compounds and of aiding in the
production of low density carrier and final product particles,
especially when crutcher mixes of a base composition are spray
dried at elevated temperatures. The preferred compounds of this
type are water soluble salts of substituted or unsubstituted ben-
zene sulfonic acids, such as the sodium and potassium salts thereof
(the alkali metal salts), especially the sodium salts. Although
alkali metal benzene sulfonates, such as sodium benzene sulfonate,
are useful hydrotropes and may be employed in the processes of this
invention, it is preferred to have one or more hydrogens of the
benzene ring substituted, as by a lower alkyl group of 1 to 4 car-
bon atoms, preferably 1 to 2 carbon atoms and most preferably one
carbon atom (methyl), e.g., sodium toluene sulfonate, sodium xylene
sulfonate, potassium toluene sulfonate and corresponding salts of
cumene, mesitylene, ethylbenzene and
.~
110(~376
pseudocumene. Usually, the sulfonates are mixtures of isomers,
with para- and ortho-configurations normally and preferably dominat-
ing, e.g., sodium p-methyl benzene sulfonate, sodium O,O-di-methyl
sulfonate, sodium o,p-dimethyl benzene sulfonate. Also, mixtures
of the various different types of hydrotropes may be used, e.g.,
sodium toluene sulfonate and sodium xylene sulfonate or the corres-
ponding potassium salts.
The nonionic detergents employed are preferably poly-
ethoxylated higher fatty alcohols such as the water soluble con-
densation products of 3 to 15 mols of ethylene oxide, preferably
7 to 11 mols, and higher fatty alcohols of 10 to 18 carbon atoms,
preferably 12 to 15 carbon atoms. Such nonionic detergents melt or
soften sufficiently to be sprayable in droplet form at a tempera-
ture below 45C. A preferred commercial product, which is the con-
densation product of a higher fatty alcohol mixture of 12 to 15
carbon atoms with about 7 mols of ethylene oxide per mol of fatty
alcohol, is sold under the trademark Neodo ~ 25-7, manufactured by
Shell Chemical Co. Other commercial nonionic compounds of this
general type which are also suitable include: Neodol 45-11, (also
made by Shell Chemical Company); Alfonic~ 1618-65, which is a 16 to
18 carbon alkanol ethoxylated with an average of 10 to 11 mols of
ethylene oxide per mol, manufactured by Continental Oil Company;
and Plurafac~ B-26, manufactured by BASF-Wyandotte.
110(1 376
In addition to the preferred polyethoxylated higher
fatty alcohols and similar alkanols there may also be used,
at least in part, e.g., up to 25 or 50%, various other nonionic
detergents such as are described at length in McCutcheon's
_etergents and Emulsifiers, 1973 Annual and in Surface Active
Agents, Vol. II, by Schwartz, Perry and Berch (Interscience
Publishers, 1958). Such nonionic detergents are usually pasty
or waxy solvents at room temperature (20C.) and are either
sufficiently water soluble to dissolve promptly in water,
especially in the presence of the hydrotrope, or quickly melt
and disperse therein at the temperature of the wash water, as
when that temperature is a~ove 40 or 50C. They will normally
not be fluid at room temperature because in such state they
might tend to make a tacky agglomerate of the final particulate
detergent, which could be poorly flowing and could lump or set
on storage. Typical useful nonionic detergents which may be
employed, providing that they are satisfactorily detersive in
the present compositions at the concentrations utilized, e.g.,
Q.l to 0.2% of detergent composition in ~ash water, are the
poly-lower alkenoxy derivatives that are usually prepared by
the condensation of lo~er (2 to 4 carbon atoms) alkylene oxide,
e.g., ethylene oxide, pr~pylene oxide (~ith enough ethylene
oxide to make a water soluble productl, with a compound having
a hydrophobic
B -lo-
~1~03!76
: ~
., ' ,:
e.g., hydrocarbon, chain containing one or more active hydrogen
atoms, such as higher alkyl phenols, higher fatty acids, higher
fatty mercaptans, higher fatty amines, higher fatty polyols and the ~
higher fatty alcohols previously mentioned. Generally, such com- ~ ;
pounds will be alkoxylated with an average of about 3 to 30, pre-
ferably 3 to 15 and more preferably 7 to 11 alkylene oxide units.
The most preferred nonionic detergents are those represented by the
formula RO(C2H4O)nH, wherein R is the residue of a linear saturated
primary alcohol (an alkyl) of 12 to 15 carbon atoms and n is an
integer from 7 to 11. Among additional nonionic detergents that
may be employed are the Igepals~9 (GAF Co. Inc.); Pluronics~
(RASF-Wyandotte); Poly-Tergents~ (Olin Corp.); and Amidoxes~
(Stepan Chemical Co.).
In addition to the adjuvants previously mentioned, which
~ are preferably post-added to the spray dried base particles, small
I proportions of anionic and amphoteric detergents may also be pre-
sent in the base beads or may be post-added. Such are not neces-
sary for the production of the desired detergent particles and if
employed are normally present in small proportions, e.g., 0.5 to
2%. Examples of such materials include the alkali metal, prefer-
ably sodium, higher alkyl benzene sulfonates having 12 to 15 carbon
atoms in their alkyl groups, which are preferably linear; higher
fatty alcohol sulfates; higher alkyl sulfonates; higher olefine
sulfonates; and polyethoxylated higher fatty alcohol sulfates. In
such cases the higher alkyl or alkene groups
-11-
110(~376
are usually of 1 to 20 or 12 to 18 carbon atoms and polyethoxyla-
tion is to the extent of 3 to 30 or 3 to 15 alkylene oxides per
mol. Instead of the synthetic anionic organic detergents mentioned
the ordinary fatty acid soaps, usually sodium soaps of mixed higher
fatty acids of 8 to 18 carbon atoms, such as those obtained from
tallow and coconut oil, may desirably be substituted in whole or in
part and mixtures of the anionic detergents may be used, with the
total amount being within the percentage range previously given.
Instead of the anionic detergents amphoteric surface active agents
may be employed. These are usually higher fatty carboxylates,
phosphates, sulfates or sulfonates which contain a cation sub-
stituent such as an amino group which may be quaternized, for ex-
ample, with lower alkyl groups, or may have the chain thereof ex-
tended at the amino group by condensation with a lower alkylene
oxide, e.g., ethylene oxide. Representative commercial water sol-
uble amphoteric organic detergents include Deriphat~ 151 and
Miranol~ C2M. Sometimes it may be desirable to employ small pro-
portions of cationic organic surface active agents, especially as
anti-static or softening materials. Typical of such compounds are
thoduomeens~ T/12 and T/13, which are ethylene oxide condensates
of N-tallow trimethylene diamines (Armour Industrial Chemical
Company) and Ethylqua ~ 18/12, 18/25 and 0/12, which are poly-
ethoxylated quaternary ammonium chlorides (Armour Industry Chemical
Co.). Various other synthetic detergents and
376
surface active agents which may be employed are disclosed in
the McCutcheon and Schwartz et al. texts.
To manufacture the low density particulate built
synthetic organic detergent composition and the corresponding
low density base composition particles, which are usually
substantially inorganic with respect to the normally solid
components thereof, an aqueous solution-dispersion, commonly
referred to as a crutcher mix, is prepared, containing the
various heat-resistant components of the final product, except
the nonionic detergent and any materials best post-added. To
save energy and to increase throughput of the drying equipment
the crutcher mix ~ill usually be of as high a solids content
as feasible, e.g. about 50 to 80%, with the balance, about
2Q to 50%, being watex. More water may be used but th~n energy
demands are increased, tower throughputs are diminished,
products resulting may be tackier and poorer flo~ing and often
the desired lo~ density ba$e and final detergent composition
particles will not be obtained. ~hen the moisture content of
the crutcher mix is about 20 to 50% the ~ater soluble,
inorganic buildex salt(s~ content ~ill be about 10 to 50%,
inorganic filler s~alt(s~ content will be about 5 to 50% and
the water soluhle~ organic hydrotropic salt(s) content will be
ahout Q.2 to 5%. ~hen no inorganic filler salt is present the
inorganic builder salt content may he
B -13-
110(~376
such as to be the balance of the composition, in addition to the water and
hydrotrope (and any other heat stable adjuvants, etc., present). Sodium
tripolyphosphate, normally charged as pentasodium tripolyphosphate, is a pre-
ferred builder salt and usually constitutes at least half of the builder salt
in the crutcher. Correspondingly, the preferred filler salt is sodium sul-
fate and generally this is at least half of the filler salt content in the
crutcher mix. Of course, the content of water in the crutcher mix will be
sufficient to satisfactorily dissolve-disperse the other components present.
Although other drying methods may be employed, such as drum drying,
tray drying, fluidized bed drying, film drying, etc., the most preferred
method is spray drying, wherein the crutcher mix is sprayed at an elevated
pressure, usually from 3 to 50 kg./sq. cm., preferably 20 to 40 kg./sq. cm.,
through a spray nozzle into a drying tower, through which drying air passes
to dry the resulting droplets of crutcher mix to globular, low density, free
flowing particles. Instead of spray nozzles, equivalent atomizers of other
designs may also be used. The preferred spray tower design is counter-
current, with the height of the tower usually being from 5 to 25 meters and
with the entering hot air, usually the gaseous products of combustion of oil
or gas, being at a temperature in the range of 200 to 400C. ar.d with the
outlet air usually at a temperature in the range of 50 to 90C. Concurrent
tower designs may also be employed wherein similar inlet and outlet air
temperatures obtain. It has been mentioned in German Offenlegungsschrift
2,514,677 that low density beads are more readily produced utilizing con-
current spray drying than result from countercurrent drying but with the
method of the present invention low density products can be obtained with
either type of tower. Countercurrent drying is preferred and has the bene-
fits of greater efficiency of the drying operation because the thermal grad-
ient for removal of the moisture in the partially dried product, near the
exit of the tower, is greater.
The nozzle size for producing droplets of crutcher mix of desired
-14-
11~3~
size is chosen to produce base particles in the 6 to 160 mesh, United States
Standard Sieve Series, range. Preferably, the product is substantially of
particles in such range when it is removed from the spray tower but any off-
size particles, such as may be from 2 to 10% by weight, as result outside
such size range, may be removed by screening, may be size-reduced to the de-
sired size range or may be recycled in the same or a subsequent crutcher mix.
In some cases the 6 to 160 mesh product may be further screened to a narrower
size range, such as 8 to 100 mesh. Also, spray characteristics may be
altered so as to obtain substantially such a product from spray drying, with-
out the need for further screening or size-reduction.
After drying is complete and the particles in the desired size
range are obtained the nonionic detergent is applied to the surfaces thereof,
preferably by spraying molten detergent, which may be in concentrated aqueous
solution but preferably is free of water, onto the surfaces of the tumbling
base particles in an inclined drum, through which the particles progress from
an elevated feed end to the discharge end. Instead of an inclined drum one
may also use fluidized beds of various conventional designs and other commer-
cial mixers, such as those of the Schugi type. The proportion of nonionic
detergent, preferably polyethoxylated higher fatty alcohol, will desirably be
from 4 to 15% and the beads onto which it is sprayed will contain about 3 to
16% moisture, preferably 5.6 to 13.3% and more preferably, 5.6 to 11.1% of
water, so that the final product will constitute about 2.5 to 15%, 5 to 12%,
or 5 to 10% of water. Of course, the moisture content of the base beads may
be higher when additional moisture-free constituents are to be post-added.
The proportions of adjuvant materials will generally be held to
less than 15%, preferably less than 10% and more preferably less than 5%
total of the total product and the proportions of individual adjuvants will
be less than 5% each, preferably less than 2% each and more preferably less
than 1% each, in most cases. Thus, the total range of ad~uvant content may
be from about 0 or 1 to 15%, preferably from 1 to 5% and the individual
-15-
component concentrations may be from 0 or 0.1 to 5%, preferably 0.2 to 1%.
If a bleaching agent, such as sodium perborate, usually as the tetrahydrate
and activated, is to be incorporated with the detergent, greater percentages
thereof, e.g., 5 to 40%, preferably 10 to 30%, may be present. Thus, sodium
perborate is not considered as one of the ordinary adjuvants previously dis-
cussed. If used, it should be post-added.
For superior products it has been found desirable for the propor-
tion of builder salt or filler salt to be within the range of 3:1 to 1:2,
preferably 2:1 to 1:1.5. The bulk density of the base beads is in the range
of 0.2 to 0.45 g./cc. and that of the final product beads is in the range of
0.3 to 0.5 g./cc. Preferably the bulk densities will be from 0.2 to 0.35 and
0.3 to 0.45 g./cc., respectively.
Preferred detergent compositions of this invention comprise about
20 to 40% of sodium tripolyphosphate, 3 to 15% of sodium carbonate, 5 to 15%
of sodium silicate of Na20:SiO2 ratio in the range of 1:1.6 to 1:3, 0 to 5%
of borax 1 to 3% of sodium toluene sulfonate or sodium xylene sulfonate 20 to
50% of sodium sulfate, 4 to 15% of higher fatty alcohol polyethylene oxide
condensation product nonionic detergent and 5 to 12% of water. In such pro-
ducts the higher fatty alcohol ethylene oxide condensation product is one
which melts or softens sufficiently to be sprayable in droplet form at a
temperature below 45C. and in the process of the invention it is melted and
sprayed onto the surfaces of the spray dried particles of base material at a
temperature below 55C., while such particles are in motion and are at a
temperature below 45 & . and greater than 10C. A highly preferable process
is one wherein the moisture content of the crutcher mix is about 30 to 45%,
the crutcher mix of such a composition as to result in a spray dried final
detergent composition product which, when it includes about 7 to 13% of poly-
ethoxylated higher fatty alcohol nonionic detergent post-added to the spray
dried base beads, includes 28 to 38% of sodium tripolyphosphate, 3 to 8% of
sodium carbonate, 5 to 10% of sodium silicate of ~a20:SiO2 ratio of 1:2 to
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1100376
1:2.4, 1.2 to 2% of sodium toluene sulfonate (or sodium xylene sulfonate),
0.5 to 2% of borax, 30 to 42% of sodium sulfate and 5 to 10% of moisture. In
such a product the nonionic detergent is preferably a condensation product of
a higher fatty alcohol of 12 to 15 carbon atoms and about 7 mols of ethylene
oxide per mol of fatty alcohol, which product is sold under the trademark
Neodol 25-7. In such process, the crutcher mix, at a temperature of 80 to
105C., is sprayed into the spray drying tower, preferably a countercurrent
tower, with the tower drying air inlet temperature being in the range of 200
to 400C., and the spraying is such as to result in droplets which dry to
particles of a mixture of sizes substantially in the 6 to 160 mesh range. To
produce such particles a nozzle orifice of a 0.2 to 0.8 mm. diameter may be
employed. In the post-spraying operation the nonionic detergent is sprayed
onto the surfaces of the tumbling particles of base beads in a rotating in-
clined drum which may be at an angle of about 5 to 15 and which rotates at a
speed of about 5 to 50 r.p.m., The nonionic detergent is at a temperature of
35 to 50C. when sprayed on the tumbling particles, which are at a temperature
of 20 to 45C.
The process for manufacture of the base or carrier beads has been
described pTeviously in conjunction with the overall process for the manufac-
ture of detergent composition particles. However, allowing for about 10% ofnonionic detergent being post-added to the base beads, the preferred and the
most preferred contents of various components of the beads are somewhat
different, being 22 to 44% of sodium tripolyphosphate, 3.3 to 16.7% of sodium
carbonate, 5.6 to 16.7% of sodium silicate, 1.1 to 3.3% of sodium toluene sul-
fonate or sodium xylene sulfonate, 0 to 5.6% of borax, 22 to 56% of sodium
sulfate and 5.6 to 13.3% of water, with the more preferred ranges being 31.1
to 42.2%; 3.3 to 8.9%; 5.6 to 11.1%; 1.3 to 2.2%; 0.5 to 2.2%; 33 to 47%; and
5.6 to 11.1%, respectively.
The various advantages of the described processes and the composi-
tions resulting have been referred to previously but will be recounted
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110~376
briefly here. Principally, a built heavy duty nonionic detergent is manufac-
tured which is in particulate form, of desired low density, non-tacky, non-
caking and free flowing. It is made by an economical process which allows
for ready variation in active detersive ingredient content of the composition.
The process is environmentally acceptable, producing no undesirable smoke or
fumes from the drying means, such as a spray tower. Also, tower throughput
is increased and energy consumption is decreased. Despite the comparatively
high contents of nonionic detergent in the final particulate composition such
detergent is readily sorbed by the hydrotrope-containing beads and compara-
tively short mixing times, e.g., 1 to 5 minutes, are sufficient. The pre-
sence of the hydrotrope in the product, while not interfering with the pro-
perties of the nonionic detergent, does aid in solubilizing some compara-
tively insoluble soiling substances often present on laundry and also aids in
promoting solubility of any poorly soluble adjuvants which may be present in
the detergent, thus preventing unwanted depositing thereof onto the laundry.
For example, colorants in detergents may be prevented from being deposited on
laundry fabrics of the laundered items. However, the main advantage of the
invention is in the production of desired low density particulate products
and in this respect the present process, utilizing a hydrotropic salt of the
type described, can produce a lower density product than is obtained with
soap, mixtures of soap and nonionic detergent, and anionic detergents, em-
ployed in similar quantities.
The reason for the desirable effects noted with the present pro-
cesses is not clear. It has been theorized that the hydrotropic salt aids in
the production of a more homogeneous crutcher mix and thereby avoids the pro-
duction of weak points or rupture-prone locations on the droplet or bead as
drying is effected. Therefore, the bead can swell to a larger size and main-
tain such size as it is dried, leading to the production of a lower density
product. However, even if such theory should become verified it would still
be unexpected that the small proportion of hydrotropic salt utilized would be
-1~-
X
1101~3~76
sufficiently effective to significantly modify the characteristics of a
crutcher mix or base droplet containing such a high percentage of inorganic
salts.
The detergent compositions of this invention, when employed in the
same manner as conventional heavy duty particulate detergents, at normal use
concentrations, e.g., 0.1 to 0.2%, in cold, warm or hot wash waters, result
in very satisfactory cleaning of the articles of laundry being washed. Addi- r
tionally, the particulate detergent may be made into a paste with water for
treatment of heavily soiled areas of the laundry and the presence of the
10hydrotrope assists in loosening such soil so that it may be more readily re-
moved during washing.
The following examples illustrate but do not limit the invention.
Unless otherwise mentioned, all parts in the specification are by weight and
all temperatures are in C.
EXAMPLE 1
A crutcher mix is made of 23.9% of sodium tripolyphosphate, 3.6% of
sodium carbonate, 5.1% of sodium silicate, 1.1% of sodium toluene sulfonate,
0.7% of borax, 25.6% of sodium sulfate and 40% of water. All the components
except the sodium silicate and the water are added as anhydrous powders.
Sodium silicate is added as 10.2% of a 50% aqueous solution and its Na20:SiO2
ratio is 1:2.35. The aqueous composition is mixed in a conventional heated
detergent crutcher for a period of about 15 minutes (polyphosphate is added
last) and is pumped by a high pressure pump (Triplex) at a pressure of 25 kg./
sq. cm. and at a temperature of 95C. into the top of a 20 m. tall spray
tower through a plurality of 0.5 mm. dia. nozzles, which create a spray of
droplets of sizes substantially in the 6 to 160 mesh, United States Standard
Sieve Series, range, which produce beads of a similar size. The drying air,
entering the bottom of the tower, is at a temperature of about 300C. and
when it leaves the tower at the top it is at a temperature of about 90C.
The droplets of sprayed crutcher mix, falling through the tower, have an
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1~003!76
average residence time therein of about one minute, with residence time modi-
fications, depending on particular drying conditions, being variable to from
30 seconds to three minutes. The spray dried beads, comprising over 95% of
particles in the desired 6 to 160 mesh range, are withdrawn from the tower at
a temperature of about 45C., after some preliminary cooling at the base of
the tower. The beads at this temperature are delivered to an inclined rotat-
ing drum wherein there is sprayed onto the surfaces thereof a melt of Neodol
25-7 (higher fatty alcohol mixture of about 12 to 15 carbon atoms poly-
ethoxylated with about 7 mols of ethylene oxide per mol) at a temperature of
about 40C. The drum is inclined at an angle of about 7 and residence time
of the particles therein is about 3 to 5 minutes. The spray nozzles are such
that the droplets of spray are of sizes corresponding to about 100 to 200
mesh ant the sprays are directed onto the surfaces of the tumbling particles.
During the tumbling the product is cooled somewhat and after removal from the
tumbling drum it is additionally cooled to a temperature in the 20 to 30C.
range, after which it is ready for packaging.
The product made is an excellent heavy duty laundry detergent,
especially good for cold and warm water use, wherein it is superior to many
detergents based on anionic synthetic active ingredients. Its bulk density
before packaging is about 0.34 g./cc., having been increased slightly during
the add-on of nonionic detergent, from about 0.29 g./cc. The moisture con-
tent to which the crutcher mix content had been dried to form the base beads
is 7.7%. The final detergent composition is of the following analysis: 33%
sodium tripolyphosphate; 5% sodium carbonate; 7% sodium silicate; 1.5% sodium
toluene sulfonate; 1% borax; 35.5% sodium sulfate; 10% nonionic detergent;
and 7% water.
In a control experiment, when the same operational steps are re-
peated with the same composition except that the sodium toluene sulfonate is
omitted from the crutcher mix, the density of the spray dried base beads re-
sulting is over 0.5 g./cc. and that of the finished detergent composition
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particles is 0.59 g./cc., which is objectionably high for a product designedto be commercially marketed in replacement of conventional spray dried deter-
gent compositions.
In modifications of the process of the invention the drying of the
crutcher mix is effected by drum and tray drying and the products resulting
are size reduced to the desired 6 to 160 mesh and narrower ranges. By such
method a desirable lowering of the density of the product into the 0.3 to
0.5 g./cc. range is obtained whereas without the presence of the hydrotropic
salt a higher density, outside such range, may result. The bulk density may
be desirably lowered further by aerating the mix before drying, with the
hydrotropic salt present therein. Also, further lowerings of the bulk den-
sity of the drum dried and tray dried products, as well as those made by
spray drying, as described above, are obtained when the particle size ranges
are from 8 to 140 and 8 to 100 mesh, with particles outside such ranges being
removed and subjected to size reduction or recycling treatments.
In other modifications of the described experiment, utilizing spray
drying, the proportions of the various components of the crutcher mix are
individually modified, +10, +20, and +30%, while still remaining in the
ranges specified, with the proportions of other components remaining con-
stant. In such cases the processing conditions are also changed, with thecrutcher mix temperature being modified to 85, 90 and 100C., the spray
nozzle cross-sectional area being increased and decreased 10% and the drying
air inlet temperature being changed to 250 and 350C. in various experi-
ments. Also, in addition to utilizing the inclined drum described, the angle
thereof is modified to 5 and 12 and in some cases the nonionic detergent is
applied in a Schugi apparatus or is directed into a fluidized bed of the base
particles. The temperature of the base beads is changed +5 C., as is that of
the nonionic detergent being sprayed onto them. In some instances 0.6% of
perfume is added with the nonionic (dissolved therein). In all such cases
useful products of the present invention are obtained, with the properties
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thereof being as described and within the mentioned desirable ranges.
EXAMPLE 2
The procedure of Example 1 is repeated, with sodium xylene sulfon-
ate being substituted for sodium toluene sulfonate, and essentially the same
types of low density base and final products are obtained. When sodium ben-
zene sulfonate is utilized instead, acceptable products result but the
effects thereof are not considered to be as good as those with the methyl-
substituted benzene sulfonates. When the potassium salts of the mentioned
hydrotropes are used, including potassium toluene sulfonate, essentially the
same types of detergent compositions are produced.
When the previous experiments are repeated, but with substitutions
of Neodol 45-11 and Alfonic 1618-65 for the Neodol 25-7, similar results are
obtained. When pentasodium tripolyphosphate is replaced by tetrasodium
pyrophosphate and when, in manufacturing non-phosphate detergents, the sodium
tripolyphosphate is completely replaced by a mixture of two parts of sodium
carbonate and one part of sodium silicate, products within the specifications
of this invention are obtainable. This is also the case when sodium sulfate
is replaced by sodium chloride or is omitted entirely, with the difference
being made up by increases in sodium tripolyphosphate and sodium carbonate,
and when sodium silicates of Na2O:SiO2 ratios of 1:2.0 and 1:2.4 are used.
g
