U.S. patent number 3,886,098 [Application Number 05/134,324] was granted by the patent office on 1975-05-27 for manufacture of free flowing particulate detergent composition containing nonionic detergent.
This patent grant is currently assigned to Colgate-Palmolive Company. Invention is credited to Walter A. DiSalvo, Edward J. Kenney, Frank R. Smith, Jr..
United States Patent |
3,886,098 |
DiSalvo , et al. |
* May 27, 1975 |
Manufacture of free flowing particulate detergent composition
containing nonionic detergent
Abstract
A free flowing particulate detergent composition containing a
nonionic detergent is made by spray drying inorganic
salt-containing base particles which have in their composition
sodium carbonate, sodium bicarbonate or sodium sesquicarbonate, a
limited amount of sodium silicate and limited amounts, if any, of
higher alkyl benzene sulfonate detergent, nonionic detergent,
sodium carboxymethyl cellulose and other detergent composition
materials which adversely affect sorption of nonionic detergent by
the base particles, and distributing over the surfaces of the
particles, as by spraying, a liquid poly-lower alkoxy lower
alkanol-containing nonionic detergent compound. Such spraying is
normally effected continuously in a tumbling drum over a short
period of time and preferably, the base particles are freshly
charged from a spray drying tower. Sodium carboxymethyl cellulose,
other organic gum anti-redeposition agents and other detergent
constituents may be tumbled in with the detergent base beads
without adversely affecting the sorption of the liquid nonionic
detergent by the beads.
Inventors: |
DiSalvo; Walter A. (North
Arlington, NJ), Kenney; Edward J. (Bernardsville, NJ),
Smith, Jr.; Frank R. (Plainfield, NJ) |
Assignee: |
Colgate-Palmolive Company (New
York, NY)
|
[*] Notice: |
The portion of the term of this patent
subsequent to September 20, 1988 has been disclaimed. |
Family
ID: |
26822224 |
Appl.
No.: |
05/134,324 |
Filed: |
April 15, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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124111 |
Mar 15, 1971 |
3838072 |
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Current U.S.
Class: |
510/326; 510/101;
510/438; 510/443; 510/497; 510/506; 510/472; 510/441; 510/351 |
Current CPC
Class: |
C11D
1/83 (20130101); C11D 1/72 (20130101); C11D
11/02 (20130101); C11D 11/0088 (20130101) |
Current International
Class: |
C11D
1/72 (20060101); C11D 11/02 (20060101); C11D
11/00 (20060101); C11D 1/83 (20060101); C11d
001/22 (); C11d 001/83 (); C11d 011/00 () |
Field of
Search: |
;252/89,99,135,531,535,539,540,550,554,558,559 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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|
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|
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525,514 |
|
Aug 1940 |
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GB |
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1,191,356 |
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May 1970 |
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GB |
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918,499 |
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Feb 1963 |
|
GB |
|
164,603 |
|
Aug 1955 |
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AU |
|
205,479 |
|
Jan 1957 |
|
AU |
|
491,125 |
|
Mar 1953 |
|
CA |
|
511,415 |
|
Mar 1955 |
|
CA |
|
540,252 |
|
Apr 1957 |
|
CA |
|
586,622 |
|
Nov 1959 |
|
CA |
|
Primary Examiner: Willis, Jr.; P. E.
Attorney, Agent or Firm: Sylvester; Herbert S. Grill; Murray
M. Tomaszewski; John J.
Parent Case Text
This is a continuation-in-part of application Ser. No. 124,111,
filed Mar. 15, 1971 now U.S. Pat. No. 3,838,072.
Claims
What is claimed is:
1. A method of producing a particulate detergent composition which
comprises making inorganic salt-containing base particles
comprising, on a detergent composition weight basis, at least 5
percent of sodium carbonate, sodium bicarbonate or sodium
sesquicarbonate, at least 5 percent and less than 30 percent of
sodium silicate, having Na.sub.2 O:SiO.sub.2 ratio of 1:1.6 to
1:3.4, less than 15 percent of soluble higher alkyl benzene
sulfonate detergent, less than 4 percent of nonionic detergent and
less than 0.5 percent of sodium carboxymethyl cellulose, with the
components of the base particles being such that the subsequently
mentioned nonionic detergent is readily sorbed thereby, and
distributing over the surfaces of the particles, while they are in
motion, from 2 to 20 percent by weight of the detergent composition
of a higher alkoxy poly-lower alkoxy lower alkanol containing
nonionic detergent wherein said higher alkoxy contains from 10 to
18 carbon atoms, said lower alkoxy and lower alkanol contains from
2 to 3 carbon atoms, the total number of carbon atoms in said poly
lower alkoxy lower alkanol being from 20 to 30.
2. A method of producing a particulate detergent composition which
comprises spraying onto the surfaces of detergent particles while
they are in motion, said detergent comprising on a detergent
composition weight basis, at least 5 percent of sodium carbonate,
sodium bicarbonate or sodium sesquicarbonate, at least 5 percent
and less than 30 percent of sodium silicate, having Na.sub.2
O:SiO.sub.2 ratio of 1:1.6 to 1:3.4, less than 15 percent of
soluble higher alkyl benzene sulfonate detergent, less than 4
percent of nonionic detergent and less than 0.5 percent of sodium
carboxymethyl cellulose, with the components of the base particles
being such that the subsequently mentioned nonionic detergent is
readily sorbed thereby, from 2 to 20 percent by weight of the
detergent composition of higher alkoxy poly-lower alkoxy lower
alkanol containing nonionic detergent, said higher alkoxy
containing from 10 to 18 carbon atoms, said lower alkoxy and lower
alkanol containing from 2 to 3 carbon atoms, the total number of
carbon atoms in the poly lower alkoxy lower alkanol being from 2 to
30.
3. A method according to claim 1 wherein the detergent composition
particles comprise from 5 to 12 percent of sodium linear higher
alkyl benzene sulfonate wherein the higher alkyl is of 12 to 15
carbon atoms, 0 to 3 percent of higher alkoxy poly-lower alkoxy
lower alkanol nonionic detergent compound wherein the higher alkoxy
is linear alkoxy of 10 to 18 carbon atoms and the poly-lower alkoxy
lower alkanol is polyethoxy ethanol of 20 to 26 carbon atoms, 5 to
75 percent sodium carbonate, 15 to 50 percnt pentasodium
tripolyphosphate, 5 to 30 percent of sodium silicate of Na.sub.2
O:SiO.sub.2 ratio of from 1:2 to 1:3, of which no more than 15
percent is dissolved in the aqueous mix that is spray dried, and
from 2 to 15 percent moisture, all of which materials are in the
base particles, sodium silicate, pentasodium tripolyphosphate and
anti-redeposition agent selected from the group consisting of
carboxy methyl cellulose, hydroxypropyl methyl cellulose, polyvinyl
pyrrolidone and polyvinyl alcohol are admixed with the base
particles, and the higher alkoxy poly-lower alkoxy lower alkanol
nonionic detergent applied to the base particles and particles
mixed with them is one in which the higher alkoxy is linear alkoxy
of 10 to 18 carbon atoms and the poly-lower alkoxy lower alkanol is
polyethoxy ethanol of 20 to 26 carbon atoms, and is from 2 to 15
percent of the detergent composition.
4. A method according to claim 3 wherein the detergent composition
particles comprise from 5 to 10 percent of the sodium linear higher
alkyl benzene sulfonate, 8 to 13 percent of the sodium silicate, 25
to 50 percent of pentasodium tripolyphosphate, 5 to 10 percent
moisture, 12 to 40 percent sodium sulfate, 2 to 40 percent sodium
carbonate, the proportion of such carbonate with respect to sodium
sulfate being at least 1:3, all of which preceding components are
in the spray dried base particles, from 5 to 10 percent of higher
linear alkoxy poly-lower alkoxy lower alkanol nonionic detergent,
applied to the base particles as a spray and from 0.5 to 5 percent
carboxy methyl cellulose, applied as a finely divided powder to the
tumbling base particles in the same tumbler in which the nonionic
detergent spray is applied thereto.
5. A method according to claim 3 wherein the detergent composition
particles comprise from 5 to 8 percent of sodium linear tridecyl
benzene sulfonate and 5 to 8 percent of higher alkoxy polyethoxy
ethanol wherein the higher alkoxy is of 14 to 15 carbon atoms and
the polyethoxy ethanol is of 22 carbon atoms.
6. A method according to claim 4 wherein from 0.1 to 2 percent of a
synthetic organic fluorescent brightening compound is present in
the base beads, causing brightening of the surfaces of the
detergent particles when contacted with the sprayed nonionic
detergent, and from 0.1 to 1 percent of perfume is sprayed onto the
beads in the tumbler.
7. A method according to claim 1 wherein the base particles are
made by spray drying an aqueous mix comprising sodium carbonate,
sodium silicate, soluble higher alkyl benzene sulfonate detergent
and water and the higher alkoxy poly-lower alkoxy lower alkanol is
sprayed onto the surfaces of the spray dried particles in fine
liquid droplet form while the base particles are in tumbling
motion.
8. A method according to claim 7 wherein the base particles to
which nonionic detergent is applied are substantially hollow
globules which pass through a 6 mesh U.S. Standard Sieve Series
sieve and remain on a 200 mesh U.S. Standard Sieve Series sieve and
are at a temperature from 10.degree. to 65.degree.C. when the
liquid spray, of particle size from 50 to 500 microns, at a
temperature of 10.degree. to 65.degree.C., is applied thereto,
which application takes place within 30 minutes after removal of
the spray dried particles from the spray dryer.
9. A method according to claim 8 wherein the detergent composition
particles comprise from 5 to 12 percent of sodium linear higher
alkyl benzene sulfonate wherein the higher alkyl is of 12 to 15
carbon atoms, 0 to 3 percent of higher alkoxy poly-lower alkoxy
lower alkanol nonionic detergent compound wherein the higher alkoxy
is linear alkoxy of 10 to 18 carbon atoms and the poly-lower alkoxy
lower alkanol is polyethoxy ethanol of 20 to 26 carbon atoms, 5 to
83 percent sodium carbonate, 5 to 25 percent sodium silicate of
Na.sub.2 O:SiO.sub.2 ratio of from 1:2 to 1:3 and from 2 to 15
percent moisture, all of which are in the base particles, and the
higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent
applied to the base particles is one in which the higher alkoxy is
linear alkoxy of 10 to 18 carbon atoms and the poly-lower alkoxy
lower alkanol is polyethoxy ethanol of 20 to 26 carbon atoms and
comprises from 2 to 15 percent of the detergent composition.
10. A method according to claim 9 wherein there is present in the
spray dried base particles, on a detergent composition basis, 15 to
40 percent sodium sulfate, with the proportion of sodium carbonate
to sodium sulfate being at least 1:3, 0 percent of higher alkoxy
poly-lower alkoxy lower alkanol nonionic detergent and 0 percent
sodium carboxymethyl cellulose, the higher alkoxy poly-lower alkoxy
lower alkanol nonionic detergent applied to the base particles is
from 5 to 12 percent of the detergent composition, with the total
of sodium linear higher alkyl benzene sulfonate and higher alkoxy
poly-lower alkoxy lower alkanol nonionic detergent being from 8 to
16 percent, and from 0.5 to 5 percent of sodium carboxymethyl
cellullose is added as a finely divided powder or in granular form
to the tumbling base particles in the same tumbler in which the
nonionic detergent spray is applied thereto.
11. A method according to claim 8 wherein from 3 to 15 percent of
sodium silicate is maintained undissolved in a crutcher mix, from
which the base particles are spray dried, by adding thereto, as one
of the last components of the crutcher mix, a hydrous sodium
silicate in particulate form of relatively large particle size,
compared to the other particulate materials added to the crutcher
mix, maintaining the temperature of the crutcher mix sufficiently
low so as to allow the hydrous sodium silicate to remain
substantially undissolved, mixing slowly after the addition of
hydrous sodium silicate, and spray drying the crutcher mix within
10 minutes after addition of the hydrous sodium silicate.
12. A method according to claim 8 wherein there is spray dried in
the base bead from 5 to 20 percent, on a detergent composition
basis, of sodium citrate, as a builder.
Description
This invention relates to the manufacture of free flowing
particulate detergent compositions which contain a nonionic
detergent constituent. More particularly, it is of methods useful
for making such compositions, which are of improved detergency,
which include overspraying certain nonionic detergents or mixtures
of such detergents onto detergent base particles, such as those
which may be made by spray drying.
In accordance with the present invention, a method of manufacturing
a particulate detergent composition comprises making inorganic
salt-containing base particles comprising, on a detergent
composition weight basis, at least 5 percent of sodium carbonate,
sodium bicarbonate or sodium sesquicarbonate, at least 5 percent
and less than 30 percent, generally less than 15 percent of sodium
silicate, less than 15 percent of soluble higher alkyl benzene
sulfonate detergent, less than 4 percent of nonionic detergent and
less than 0.5 percent of sodium carboxymethyl cellulose, with the
components of the base particles being such that the subsequently
mentioned nonionic detergent is readily sorbed thereby, and
distributing over the surfaces of the particles, while they are in
motion, from 2 to 20 percent by weight of the detergent composition
of a poly-lower alkoxy lower alkanol-containing nonionic detergent
compound wherein the poly-lower alkoxy lower alkanol is of 20 to 30
carbon atoms. For best detergency, the compositions made will
include anionic synthetic organic detergent, nonionic synthetic
organic detergent and pentasodium tripolyphosphate but the
inventive method also lends itself very well to the manufacture of
products wherein the phosphate is substantially decreased in amount
or is omitted entirely, and of others in which the anionic
detergent is also omitted. Within the invention is the manufacture
of strong sorptive essentially inorganic salts beads, suitable to
be post-sprayed with nonionic detergent or for use in formulating
detergent compositions. The products, as well as the methods for
their manufacture, are also within the invention.
In useful embodiments of the invention a detergent of the base is a
water soluble higher alkyl benzene sulfonate detergent, present in
a quantity less than that which prevents sorption of a subsequently
oversprayed nonionic detergent, the nonionic detergent of the base,
if present, is present in limited quantity and is a higher alkoxy
poly-lower alkoxy lower alkanol detergent, sodium silicate of an
Na.sub.2 O:SiO.sub.2 ratio of between 1:1.6 and 1:3.4 is present in
amount sufficient to strengthen the base bead but not to prevent
sorption of the oversprayed nonionic detergent, and the carbonate
is sodium carbonate, useful to aid in sorbing the nonionic
detergent overspray and, in the absence of the tripolyphosphate,
acting to build the detergent composition and thereby improve its
washing power. Of great importance in the present invention is the
use of sodium carbonate in the base particles, usually of spray
dried, substantially inorganic salt composition, since with the
present detergents and in the formulas described, the base beads
quickly and sufficiently sorb the nonionic overspray material to
allow it to be free flowing soon after completion of the relatively
fast overspraying operation. Thus, a product may be packaged
shortly after manufacture, using high speed filling machinery,
without fear of laziness of flow preventing satisfactory movement
through the filling machinery. The product made, in addition to
being free flowing, is essentially non-tacky. It is of good
spherical particle appearance, satisfactory white or colored and is
especially useful as a home laundry washing product.
To maintain the product free flowing and non-tacky, the amounts of
synthetic detergent, moisture, synthetic organic gum
anti-redeposition agent, sodium sulfate and pentasodium
tripolyphosphate in the detergent base will usually be limited, if
present at all. The base is best spray dried and most of the
nonionic detergent or substantially all of it will be oversprayed
as liquid onto the surfaces of the spray dried base particles while
they are in tumbling motion, at a time usually shortly after the
completion of spray drying.
By the present method there may be added to detergent compositions
liquid or near liquid nonionic detergents which significantly
improve the washing properties of the compositions and still allow
them to remain free flowing and of acceptable non-tacky properties.
When the detergent particles are relatively light in weight,
usually of a bulk density of 0.3 to 0.6 g./cc., and of readily
soluble hollow globular form, such as are produced by spray drying,
significant improvements are made in production methods over
processes wherein nonionic detersive compounds are present in the
crutcher mix and are spray dried with the other ingredients. In
such comparative spray drying operations the nonionics tend to
plume and often are lost from the spray dryer as aerosols. This can
cause air pollution and represents an economic loss. Additionally,
changes in the amounts of nonionics plumed out of the tower causes
variations in the analyses of the final products. By following the
present methods, greater tower throughput is obtainable and
formulating flexibility is realizable. Various materials may be
added to the described compositions in the tumbling drum, whereby
modifications of the product may be made over those which are
available by corresponding additions to the crutcher mix. An
additional useful feature of the present invention is in the
improved appearance of the product made, compared to products of
similar formulations wherein granular materials are tumbled
together or in which spray drying alone is utilized. Details of
such improvements will be given later.
Various compositions, methods, operations, constructions,
conditions, details, uses and advantages of the invention will be
apparent from the following description, taken in conjunction with
the illustrative drawing of a preferred embodiment thereof, in
which drawing:
FIG. 1 is a schematic flow diagram showing the manufacture of an
oversprayed spray dried detergent;
FIG. 2 is an enlarged partially sectional side elevation of
tumbling apparatus employed in the practice of the invention;
and
FIG. 3 is a sectional end elevation of the apparatus of FIG. 2.
In FIG. 1, aqueous detergent base crutcher mix 11 is agitated in
crutcher 13 by stirring means 15 which maintains it in
substantially homogeneous condition. Heating means, not shown, are
usually employed to raise and regulate the crutcher mix temperature
so as to increase the solubilities or dispersibilities of the
detergent components and to diminish the mix viscosity, so as to
facilitate spraying. A high pressure pump 17, capable of producing
pressures of 200 to 2,000 lbs./sq. in., pumps the crutcher mix
through line 19 and spray nozzles 21 when valve 23 is opened. In
spray tower 25 the sprayed droplets 27 of crutcher mix pass
downwardly through an upwardly moving stream of heated air
generated by burner 29, which air passes into the spray tower 25
through duct 31 and inlet ring 33. As illustrated, the heated air
or combustion products result from burning oil passed through
nozzle 35 with air supplied by blower 37. A vacuum is drawn on the
spray tower by blower 39 and the spent drying air is removed from
the tower through duct 41 and cyclone separator 43, which removes
fine particles from the air at 45, allowing the cleaned air to be
vented at outlet 47, after having passed through blower 39.
Additional air cleaning means, such as bag-type dust separators,
may also be used in conjunction with the cyclone separator but are
not illustrated herein.
The dried detergent particles 49, usually in hollow globular or
bead form, are removed from the spray drying tower by gravity and
air lift 51, which is operated by vacuum generated by blower 53,
and the particles travel past baffle 55 to hopper 57 for bin 58,
from which they are ready to be fed to a tumbling apparatus for
post spraying to make the product of this invention.
The various parts of the overspraying apparatus next described are
better illustrated in enlarged FIG'S. 2 and 3 than in FIG. 1. Belt
feeder 59 carries spray dried base beads 49 from bin 58 under
hopper 57 through hopper 61 and passage 63 into continuous tumbling
drum 65. Instead of utilizing the continuously rotating drum
illustrated, other continuously moving tumblers, such as twin shell
blenders, may be employed. Such other tumblers or the present drum,
if suitably modified, may be used in batch operations. In the
preferred continuous operation, other adjuvants which it may be
desirable to add before or at the early stages of tumbling may be
fed from bin 67 by feed belt 69 through line 71 to drum 65.
Materials desirably added at this time include anti-redeposition
agents, such as sodium carboxymethyl cellulose, extra sodium
silicate and sometimes, additional sodium tripolyphosphate. In
enzyme-containing detergents, the enzymes may be added at such
points or farther down the tumbling drum.
Perfume and/or any other liquid additives which are insufficiently
stable to be spray dried or which for any other reasons are
desirably added after spray drying, may be forced onto the base
beads through line 73 and out spray nozzle 75 or through other
similar lines and nozzles. Usually slightly farther down stream
than the "perfume addition" nozzle, the nonionic detergent
overspray material is similarly passed through line 77 and nozzles
79. As illustrated, three such spray nozzles are shown, each of
which is separated from the next adjacent nozzle by from one to two
feet. Separations may be varied, depending on the sizes of the
drums, and can be from 3 inches to 3 feet. The number of nozzles
may be from one to six. In some instances the perfume and other
liquid or soluble components of the formulation may be pre-mixed
with the nonionic detergent and may be sprayed with it rather than
through separate nozzles. After a sufficient residence time in the
tumbling drum, preferably in continuous operation, the treated
detergent particles 81 may have other powdered additives mixed with
them, usually to improve flow and reduce tackiness. Thus, a finely
divided clay, talc or other suitable "lubricant" or flow-inducing
agent, such as calcined aluminum silicate (Satintone), may be added
to the tumbling drum near the downstream end thereof by feeding it
from bin 83 through screw feeder 85, hopper 87 and line 89. The
various screw feeds, belt feeds and pumping rates for the liquids
to be sprayed are regulatable individually or may be controlled by
a proportioning mechanism, not shown, which maintains the desired
balances of the various material to be charged. Thus, the entire
operation may be automated.
After production of the oversprayed detergent particles 81 and
dusting thereonto of flow-inducing powder or other suitable finely
divided materials, the product is removed through exit 91 and forms
a bed 93 on vibratory feeder 95. This bed of material is
transported by the feeder to hopper 97 past screen 99 to filling
bin 101, from which it is discharged to packages 103 passing along
belt 104 under filling head 105. The packages are then
automatiically closed, sealed, cased and shipped. Any oversize
particles failing to pass through screen 99 are discharged at
takeoff 100. These and other oversized and undersized particles may
be re-worked or otherwise further processed to be made suitable for
blending with the rest of the oversprayed detergent particles
produced.
Although it is not intended to effect substantial evaporation of
moisture or other volatiles in the tumbling drum 65, a slight flow
of air through the drum is maintained by applying vacuum to the
downstream end thereof, as illustrated by vacuum hood 107. The hood
is so formed as to exert a slight effect on bed 93 of oversprayed
particles and through the bed to cause an air flow from the
upstream to the downstream end of the tumbling drum. Thus, any very
finely divided mist-like droplets of liquid to be oversprayed onto
the detergent particles will be drawn by the vacuum through the bed
93 and deposited on the particles, if this is not completely
effected in the tumbling drum. Colloidal liquid not so deposited
and very finely divided solid particles are removed via line
109.
FIG. 3 shows the relative positioning of the various lines for the
addition of detergent base particles, sodium carboxymethyl
cellulose or other resinous or gum anti-redeposition agents or
other particulate additives, overspraying nonionic detergent and
perfume or other liquid additives. It will be noted that nozzles 75
and 79 are so directed as to spray the liquids onto the moving
particles 49, which action avoids production of large quantities of
tailings due to overconcentrations of the liquids on apparatus
walls or on any relatively quiescent materials near the points of
spraying. Arrow 111 indicates the direction of rotation of the
tumbling drum.
In making the base detergent composition it is highly preferred to
employ a spray dryer, either countercurrent or concurrent, such as
are known in the detergent industry to be useful for the production
of light weight and substantially globular detergent beads, which
preferable are also hollow. Other apparatuses may be used providing
that the base particles produced are of desired particle size,
shape, density and flow characteristics. However, it is not
desirable to use agglomerated particles, made by mere mixing of
finely powdered detergent composition constituents in the presence
of a binding agent, nor is it preferred to employ dry mixtures of
ground detergent composition ingredients.
Spray drying is effected by crutching an aqueous crutcher mix of
the base detergent composition, which may be esentially inorganic
salt but often will include a synthetic organic detergent,
preferably an anionic detergent, which term includes the usual
higher fatty soaps. Of the anionic detergents the higher alkyl
benzene sulfonates, especially the water soluble salts of linear
higher alkyl benzene sulfonates, e.g., the alkali metal salts, of
which sodium linear higher alkyl benzene sulfonate is preferred,
will be employed. However, other anionic detergents and minor
proportions of nonionic detergents, providing that they do not
cause pluming in the spray tower, may also be present. Such
compounds are well known in the detergent 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. Among the important anionic
compounds so listed are the higher alkyl sulfates, the higher fatty
acid monoglyceride sulfates, the higher olefin sulfonates, the
higher alkyl sulfonates, the sulfated phenoxy polyoxythanols, the
branched higher alkyl benzene sulfonates and the higher fatty acid
soaps. Usually, such compounds or derivatives are employed as water
soluble salts and generally these are alkali metal salts, e.e.,
sodium salts, of the mentioned compounds. Also, the higher alkyl or
fatty groups will generally be of 12 to 18 carbon atoms. Of the
nonionic detergents, those are preferred which are
hydroxyl-containing linear polymers of lower alkylene oxides and
are normally liquid or semi-solid at room temperature. These
include condensation products of higher fatty alcohols with
polyoxy-lower alkylene glycols, such as Neodol 45-11, Plurafac B-26
and Alfonic 1618-65. Also useful are the block copolymers of
propylene glycol, propylene oxide and ethylene oxide, such as the
Pluronics, e.g., Pluronic L-44, and the middle alkyl phenyl
polyoxyethylene ethanols, such as those sold as Igepals. Most of
these compounds are not as good in the present detergent products
as the anionics because they usually plume objectionably when spray
dried, and can cause environmental mist problems when present in
larger proportions in the base product. Therefore, they will be
present in minor proportions, which will generally be less than
half the content of the organic detergent component of the
base.
The linear higher alkyl benzene sulfonates will normally be of 12
to 15 carbon atoms in the alkyl groups, preferably of 13 or about
13 carbon atoms and the linear alkyl will be substantially
terminally joined to the phenyl group. However, a minor proportion
thereof may be joined to the 2- or 3-carbon but generally the
amount thereof will be less than 30 percent and most of that will
be joined on the 2-carbon. Although small quantities of such
soluble sulfonates of metals other than sodium may be present, such
metals normally will be minor proportions of the salt-forming
metal. It will usually be preferred to employ the sodium higher
linear alkyl benzene sulfonate as the sole anionic detergent
constituent of the base beads, since it is a good and acceptably
biodegradable detergent, but it may sometimes be desirable to mix
it with other anionics for specific purposes. For example, small
proportions of soap, e.g., the sodium salt of an 80:20 or 85:15
tallow-coconut oil fatty acids mixture, may be present.
The greater part of the solids content of the crutcher mix is of
inorganic salts, principally as builders or fillers for the
detergent. An important builder salt constituent of this type is
sodium silicate, although other alkali metal silicates may also be
used. Of the sodium silicates which are employed, those having an
Na.sub.2 O:SiO.sub.2 ratio of from 1:1.6 to 1:3.4 are generally
useful, either as the entire silicate content or a part thereof.
Silicates of Na.sub.2 O:SiO.sub.2 ratio of 1:2 to 1:3 are preferred
and of them those of ratios of 1:2 to 1:2.5, specifically 1:2.3,
are presently most preferred, although 1:2 silicates may be most
used in the future. These silicates have building properties, add
desired alkalinity, are anti-corrosive and are suitable for
producing good crutcher mixes and stronger detergent beads. Other
useful builders include pentasodium tripolyphosphate and
tetrasodium pyrophosphate. Trisodium nitrilotriacetate is a good
builder, if environmentally acceptable, but its content should be
minor because of a tendency to counter sorption of the nonionic
overspray. Additional compounds which serve as builders, usually
most effective in the absence of phosphates, are borax, sodium
carbonate, sodium bicarbonate and sodium sesquicarbonate. A good
filler salt is anhydrous sodium sulfate and sodium chloride may
sometimes also be employed.
Various other constituents and adjuvants may be present in the
crutcher mix or may be post-added, including sanitizers, e.g.,
trichlorocarbanilide, coloring agents, e.g., dyes and pigments,
foam improvers, foam depressants, fungicides, anti-oxidants,
stabilizers, chelating agents, optical bleaches or fluorescent
brighteners, soil suspending agents and soil anti-redeposition
agents. Of the foregoing adjuvants those of most importance to the
present invention, especially with respect to ready operativeness
of the method and unexpected improvements in the products, are the
anti-redeposition agents, including natural and synthetic organic
gums or resinous materials which aid in maintaining the removed
soil and other constituents of a detergent wash water in suspension
so that they are not deposited on the laundry as the rinse water is
drained through it. Such compounds include sodium carboxymethyl
cellulose, polyvinyl pyrrolidone, polyvinyl alcohol and similar
agents known in the art. The fluorescent brighteners are members of
a well-known class in the detergent art and usually are reaction
products of cyanuric chloride and the disodium salt of diamino
stilbene disulfonic acid, benzidine sulfone disulfonic acids, amino
coumarins, diphenyl pyrazoline derivatives or naphthotriazoly
stilbenes. Such materials are described in the article Optical
Brighteners and Their Evaluation by Per S. Stensby, a reprint of
articles published in Soap and Chemical Specialties in April, May,
July, August and September, 1969, especially at pages 3-5 thereof.
They include cotton brighteners, polyamide brighteners, polyester
brighteners and bleach-stable brighteners of the types mentioned,
such as those sold as Stilbene No. 4, Calcofluor White ALF
(American Cyanamid), SOF (Ciba), Blancophor PD (GAF) and Tinopal
RBS (Geigy). These are of complex structures. For example, the
formula of Stilbene No. 4 is disodium
4,4'-bis-(4-anilino-6-morpholine-s-triazin-2-ylamino)
-2,2'-stilbene disulfonate. Yet, despite the complexities of their
structure and their differences, the brighteners act to whiten the
detergent particles made according to this invention.
The base head composition will depend to some extent on the type of
final detergent product that it is intended to make. Thus, where
making a product of excellent cleaning power is most important
there will often be present therein significant quantities of
pentasodium tripolyphosphate or other phophate builders, with an
anionic detergent, such as the sodium salt of linear higher alkly
benzene sulfonic acid. Although the phosphate may be post-added, it
will generally be preferred to spray dry a significant proportion
of, it not most or all of it, in the beads. Small quantities of
nonionic supplementing detergents may also be present in the
crutcher mix. When large proportions of phosphates may not be used
in detergents, the quantities thereof may be approximately halved
and other inorganic salts may be employed for their building or
filler effects. Thus, with less phosphate, more silicate, carbonate
and sulfate will usually be present. When phosphates are eliminated
entirely, the amounts of carbonates and filler salts may be further
increased to make up for its absence. It has been found that
silicate content of the crutcher mix should not be increased over
about 30 percent to avoid having the beads of low sorptive effect
with respect to the nonionic detergent applied to them. In those
instances where detergent application is by overspraying, ratther
than by incorporation in the crutcher mix and wherein neither
phosphates nor anionic surface active agents are to be present in
the base beads, the crutcher mix may almost entirely of inorganic
salt, principally sodium carbonate (sodium sesquicarbonate and
sodium bicarbonate may be employed, too), with an allowable
proportion of sodium silicate, which improves the strength of the
spray dried carbonate beads. Depending on which type of formulation
is being made, proportions of constituents will be regulated
accordingly.
The proportions of the various components in the crutcher mix from
which the spray dried bead is produced are regulated so as to
obtain a bead on which the nonionic surface active or detergent
overspray may be deposited and in which it will be sorbed without
causing the production of sticky, tacky or poorly flowing beads.
The crutcher mix will usually comprise from 25 to 75 percent
solids, preferably from 50 to 70 percent, with the balance being
mostly, almost entirely or only water. The proportions of various
crutcher mix constituents will be such as to result in detergent
products having the compositions given below. Percentages of
constituents calculated on a detergent product basis are considered
to be more convenient to use than percentages based on either the
crutcher mix or the spray dried base beads, which would require
re-calculations to determine concentrations in the product. Of
course, the products can be re-formulated with other materials to
make still more "end" or "final" detergent products. Thus, colored
detergent or inorganic salt particles may be blended in with the
products to produce dotted effects or the products can be diluted
with filler particles to produce detergents of varying active
ingredient concentrations.
The quantity of silicate employed will generally be from 5 to 50
percent in the final product and about 5 to 15 percent of soluble
sodium silicate is acceptable in the crutcher mix. The remainder is
usually post-added but when its solubility can be retarded, as by
late addition to the crutcher mix, little agitation, low crutcher
temperature, large particle size and temporary coating with other
materials, or any suitable combination of these, to prevent
dissolving in the crutcher mix, 1 to 15 percent of a hydrous sodium
silicate may be employed in the crutcher, together with the soluble
silicate, so that the total silicate therein does not exceed about
30 percent and the soluble silicate is from 5 to 15 percent. The
hydrous silicate used may be made by spray drying an aqueous
solution of sodium silicate of a suitable ratio of from about 1:1.8
to 1:2.5 Na.sub.2 O:SiO.sub.2, with, preferably about a 1:2 ratio,
to a moisture content of about 10 to 25 percent. Although the use
of such a hydrous undissolved silicate in the crutcher allows a
higher silicate content in the product and avoids the use of
metering equipment to add silicate in the tumbling apparatus in
which overspraying takes place, because of the need to carefully
watch the crutching operation to prevent any solubilization of more
than 15 percent of sodium silicate, it will sometimes be preferred
to post-add silicate, rather than to employ the temporarily
insoluble material in the crutcher. With respect to the soluble
silicate in the crutcher mix, 12 percent is a preferred limit and
10 percent is most useful in the spray dried base. At 5 to 15
percent concentration in the spray dried base beads the silicate
exerts a significant building effect and strengthens the bead but
does not inhibit sorption of the nonionic detergent of the
overspray so as to produce a poorly flowing or tacky product. Use
of more than about 15 percent of soluble sodium silicate in the
crutcher mix causes a significant lumping of the base beads and a
decrease in flowability of the oversprayed particles and therefore,
is to be avoided. When other consitutents which have negative
effects on flowability or non-tacky properties of the product are
also present, the proportion of soluble sodium silicate will
usually be decreased further, as to 10 percent or 8 percent. Below
5 percent content thereof its building properties and contribution
to increased particle strength are not substantial. An additional
20 percent of silicate, over the 30 percent mentioned, may be
present in the final product, if post-addition of silicate is
practiced.
Although the silicate content may usually be varied over the 5 to
15 percent range for a variety of detergent compositions of this
invention, the concentrations of the various other, more
significant components of the detergent base beads utilized will
depend more on the desired end properties of the compositions and
the types of compositions. By types of composition is meant the
phosphate content, high, low or medium, and none, and the organic
detergent content. Thus, when phosphate content varies from 0 to 50
percent, usually being from 15 or 20 to 50 percent, the contents of
carbonates, sulfate and other builder adjuvants will be adjusted
accordingly. For a high pentasodium tripolyphosphate composition,
one having from 25 to 50 percent of the tripolyphosphate, the
proportions of other constituents can be from 5 to 10 percent of
sodium linear higher alkyl benzene sulfonate, 8 to 13 percent of
soluble sodium silicate, 12 to 40 percent sodium sulfate, 5 to 40
percent sodium carbonate (the proportion of carbonate to sulfate
being at least 1:3), 5 to 15 percent moisture and from 0.1 to 2
percent of a synthetic organic fluorescent brighhtening compound.
The foregoing materials are generally present in the base beads
made but the percentages are on a final composition basis. Such
base beads, like, the other described herein, include less than 0.5
percent of sodium carboxymethyl cellulose and usually less than 4
percent of nonionic detergent, preferably 0 to 3 percent thereof
and most preferably 0 percent. Such a detergent is usually a higher
alkoxy poly-lower alkoxy lower alkanol nonionic detergent.
Generally broader ranges of constituents, for phosphate-containing
formulas having 15 to 50 percent of the phosphate include from 5 to
12 or 15 percent of sodium linear higher alkyl benzene sulfonate of
12 to 15 carbon atoms, 0 to 3 percent of the nonionic detergent, 5
to 75 percent of sodium carbonate, 5 to 30 percent of the sodium
silicate of Na.sub.2 O:SiO.sub.2 ratio of 1:2 to 1:3, and 2 to 18
percent moisture, in the base beads. In compositions which may be
devoid of phosphates but still include anionic detergent, from 5 to
12 percent of sodium linear higher alkyl benzene sulfonate may be
present, with 0 to 3 percent of the nonionic detergent, 5 to 83
percent of sodium carbonate, 5 to 25 percent of sodium silicate,
but not more than 15 percent water soluble, and 2 to 15 percent of
moisture. In preferred embodiments of such compositions, there is
no nonionic detergent and no sodium carboxymethyl cellulose present
in the crutcher and the sodium sulfate content is from 15 to 40
percent. When the base beads comprise principally sodium silicate
and sodium carbonate, bicarbonate or sesquicarbonate or mixtures
thereof, the silicate will usually be from 5 to 30 percent, with no
more than 15 percent being water soluble, the carbonate will be
from 40 to 87 percent, adjuvants will comprise 0 to 5 percent and
moisture will be 2 to 15 percent from the base. In some preferred
processes and compositions the sodium carbonate content will be
from 40 to 70 percent. On a base bead basis, 70 to 95 percent may
be sodium carbonate and 5 to 30 percent sodium silicate. It has
been found that up to about 20 percent of sodium citrate can be
substituted in the various formulas for phosphate, sulfate and to
an extent, for carbonate and silicate. In such formulations from 5
to 20 percent of the citrate is useful. The sodium citrate performs
some builder functions but is not as effective in this respect as
the phosphates. Among other useful builders that may be employed is
sodium dioxyacetate, in amount like that mentioned with respect to
the citrate. The inorganic builders include borax, usually from 5
to 25 percent and preferably from 5 to 15 percent of the
composition. NTA may be utilized generally to the extent of 5 to 20
percent, but will be omitted in present formulations, in compliance
with government recommendations. Among the fillers or extenders, in
addition to the sodium sulfate, up to 15 percent and preferably
less than 8 percent of sodium chloride may be used. In the above
description various compounds are referred to as builders although
they may have only a fraction of building effects of the
tripolyphosphates, because, in the absence of the phosphates, such
materials are relied upon to improve washing action.
The synthetic organic detergent component will usually be from 5 to
15 percent of the product and is preferably the mentioned sodium
linear alkyl benzene sulfonate. The content of such detergent
compound should generally not exceed 20 percent of the product, nor
be less than 5 percent thereof to have any significant detersive
effect. Other anionic or nonionic detergents may be used to
supplement or partially replace the alkyl benzene sulfonate but
normally such total content of other synthetic detergent (s) will
not exceed the amount of sodium alkyl benzene sulfonate present in
the crutcher mix. Genrally, the amounts of supplementing detergent,
if present at all, will be less than 10 percent. For example, from
0.1 to 5 percent of soap may be used, or 2 to 5 percent of sodium
higher alkyl sulfate, or from 0.1 to 4 percent, preferably 1 to 2
or 3 percent, of nonionic, if present. The contents of various
adjuvants in the base beads will usually be limited to about 15
percent of the product and generally will be less than 10 percent
thereof, preferably less than 5 percent. The content of
anti-redeposition agents, e.g., CMC, will be held as low as
feasible in the crutcher because these materials counter sorption
of the nonionic overspray. Usually the maximum proportion of such
anti-redeposition agent in the base beads will be about 0.5 to 1
percent, preferably about 0.5 percent and desirably will be 0.2
percent or less. when greater quantities of CMC or other
anti-redeposition agent are to be present, they may be added to the
tumbling drum in proportions up to 6 percent, since it has been
found that such additions do not prevent sorption of the overspray
nonionic detergent. It is highly preferable that all the CMC or
other anti-redeposition agent be tumbled into the detergent
formulations, rather than be spray dried with it. If bleaches, such
as sodium perborate, are present, the content thereof will usually
be from 1 to 30 percent, with some or all of the bleach being
post-added. The various other constituents present will normally
not exceed 2 percent and preferably will be held to 1 percent each,
if present. Moisture contents of the spray dried beads will be from
1 to 18 percent, preferably from 3 to 15 percent and most often
will be in the 5 to 12 percent range. This will also approximate
the moisture contents of the final detergents made. After
completion of the manufacture of the spray dried beads, accoring to
a method which will be described subsequently, there is distributed
over the surfaces thereof the nonionic detergent, which
significantly improves washing action. Applications of liquid
nonionic detergents to granular mixes of organic detergent and
inorganic builder and filler salts have been effected in the past.
However, the amounts of liquid nonionics employed usually had to be
low, often under 1 percent or even under 0.5 percent, which small
amounts could alleviate dusting problems and would not cause
lumping or tackiness of the product but would also not greatly
increase detergency. It has now been found, in accordancne with
this invention, that from 2 to 20 percent, preferably 2 to 15
percent and most preferably about 5 to 10 or 12 percent higher
linear alkoxy poly-lower alkoxy lower alkanol detergent may be
oversprayed onto the base beads. Such detergent is preferably one
in which the higher linear alkoxy is of 10 to 18 or 10 to 16 carbon
atoms, most preferably of 12 to 15 carbon atoms and the poly-lower
alkoxy lower alkanol is one in which the lower alkoxy and alkanols
are of 2 to 3 carbon atoms each, with the total of carbon atoms in
the poly-lower alkoxy lower alkanol, which is preferably polyethoxy
ethanol, being 20 to 30. Preferably, the higher alkoxy is of 14 to
15 carbon atoms and the polylower alkoxy lower alkanol is of about
22 carbon atoms. Such compounds are commercially available from
Shell Chemical Company under the name, Neodol 45-11. Nonionic
detergents similar to Neodol 45-11, made by Shell Chemical Company
or other manufacturers, are also useful when they are of 10 to 18
or 13 to 16 carbon atoms in the higher alkanol and of 20 to 26
carbon atoms in the polyethoxy ethanol portions of the molecule.
The nonionic overspray materials used will be liquid under the
conditions of use and will preferably remain liquid or near-liquid
after manufacture. Surprisingly enough, rather than such liquid
state causing a plasticizing action and resulting in agglomeration
or adherence of the particles to each other, it seem to promote
penetration of the base beads and removal of the liquid from the
surfaces thereof, causing the product to be free-flowing, and
non-tacky.
With the application of the overspray nonionic detergent it may
sometimes be desirable for other constituents of the final product
to be added during the tumbling operation. For example, although in
the drawing, perfume or other liquid additive is sprayed onto the
tumbling particles through a nozzle separate from those utilized
for the nonionic detergent, it may be blended in with the nonionic
and sprayed through a single nozzle. Similarly, other liquid or
soluble components or adjuvants may be sprayed. For example, amine
anti-foam agents such as di-higher alkyl amine, e.g., dicocoyl
amine, which may be present to the extent of 0.2 to 3 percent,
usually about 1 or 2 percent, may be dissolved in the Neodol 45-11,
together with the perfume. Likewise, foaming agents, bactericides,
dyes and other coloring agents, solvents, etc., may be sprayed onto
the base particles, either separately or together with other such
materials. Mixtures of the nonionics, e.g., mixtures of Neodol
45-11, Alfonic 1618-65 and Plurafac B-26 may be employed.
To make no-foam detergents one will usually employ 2 percent soap +
1 percent DCA (dicocoyl amine) or 2 percent of the amine, without
any soap, in otherwise nonionic detergent formulas. Using 2 percent
soap alone in such formulas makes a low foaming detergent. The use
of DCA-Neodol 45-11 mixtures to apply them to the base detergent
beads by overspraying gives a flowable non-tacky product superior
to that obtained from separate oversprayings or from crutching the
DCA and/or nonionic and spray drying.
In the tumbling apparatus or other suitable mixer in which the
overspraying is effected, it will often be desirable for other
constituents of the final product to be added. Usually, the most
important of these is the anti-redeposition agent and from 0.2, 0.3
or 1 to 5 percent of such an agent, preferably sodium carboxymethyl
cellulose (CMC), hydroxypropyl methyl cellulose or polyvinyl
alcohol, will often be blended in with the base detergent beads
before overspraying. In some formulations, no organic
anti-redeposition agent is needed but generally CMC will be a very
useful additive. Stain-removing enzyme can be added at the same
location as the CMC, usually to the extent of about 0.05 to 1
percent, and in the form of prills. The perfume content, generally
from 0.1 to 1 percent of the product, may be added as previously
described. If it is desired to further promote whitening or
brightening of the surfaces of the particles a fluorescent dye or
optical brightener, if soluble, may be applied in the
overspray.
When considered to be advantageous, proportions of other
constituents, normally as solid particles, may be incorporated in
manner similar to that in which sodium carboxymethyl cellulose may
be added. In such cases, corresponding amounts of such materials
can be removed from the base formula. Such additions are especially
desirable when the materials to be added in the tumbler are of
substances which, in the spray dried or homogeneous detergent
beads, inhibit penetration of the overspray into the beads, as do
CMC and excess anionic detergent. For example, portions of sodium
silicate and sodium sulfate may be added in the tumbler, rather
than in the crutcher mix, to permit more ready processing of
formulating containing larger amounts of these materials than would
otherwise be desirable. On the other hand, sodium carbonate will
usually not be post-added because it aids penetration of nonionic
overspray into the interior of the base beads if it is in the bead
formula. The post-added solid material in excess of 5 percent
should preferably be granular (of particle size like that of the
base bead). However, the CMC is usually added as a finely divided
powder.
The oversprayed particulate detergent produced according to the
foregoing formula and general procedure will be free flowing and
does not tend to cake objectionably on storage. Thus, when at a
density of about 0.3 to 0.6 grams/cu. cm., packed in cardboard
detergent cartons, it pours easily despite storage at ordinary
temperatures in humid atmospheres. Such a detergent box need
usually only be tilted slightly to allow pouring of the contents as
they are being measured for addition to a washing machine. For
further insurance of excellent flow properties, however, it may
sometimes be desirable to add from 0.2 to 3 percent of a very
finely divided flow improving clay for such purposes, such as
calcined aluminum silicate, sold as Satintone. Such additions will
preferably be at a point near the outlet from the tumbling drum or
will be effected near the end of the tumbling or mixing operation,
after addition of the overspray liquid. This is done so that the
clay will not be worked into the body of the detergent bead but
will remain thinly spread out over the surfaces thereof to promote
easy slip and free flow. For best effects, the clay should be
sufficiently finely divided so as to pass substantially entirely
(98 percent or more) through a 325 mesh sieve. Other ingredients,
including salts and CMC, etc., can be added at either end of the
mixer or intermediately but preferably are added upstream, with
only Satintone being added at the downstream end.
Production of the homogeneous base may be by any suitable
well-known method employed in the art. In spray drying operations,
the general operation will be as outlined in the figures of the
accompanying drawing. The crutcher mix will be heated to a
temperature of about 60.degree. to 90.degree.C. and will be sprayed
through spray drying nozzles at a pressure of 200 to 2,000 lbs/sq.
in. to globular droplets which will pass through drying gas,
usually at a temperature of 150.degree. to 300.degree.C., and will
have their moisture content reduced to 15 percent or less. The
dried particles resulting, which may be at 10 to 65.degree.C. but
are usually at 27.degree. to 43.degree.C., will largely be in the 6
to 200 or 6 to 140 mesh particle size range but may be screened to
remove tailings. Preferably, the particles will be produced in the
8 to 100 mesh range, U.S. Standard Sieve Series.
When spray dried detergent particles are fresh and warm, having
been spray dried within the half hour, often within 5 minutes or
less and being at a temperature of from 27.degree. to 43.degree.C.,
they are often soft so that upon addition of liquid materials they
would be expected to agglomerate and become tacky. It is a feature
of the present invention that, utilizing the homogeneous and
preferably hollow globular detergent base beads with the particular
nonionic detergent overspray described, overspraying is possible on
fresh warm base particles without objectionable agglomeration.
Thus, special cooling and/or storage of the spray dried base
particles are not neccessary and the efficiency of the
manufacturing operation can be raised substantially. In fact, it is
preferred to use fresh warm base particles, usually within 30
minutes to an hour after making and sometimes within five minutes
or less. Rather than producing tacky or poorly flowing product as
might have been expected, the fresh warm particles are usually even
more sorptive than aged particles (several hours or a day old) and
the product is better. The minor amount of agglomeration which may
occur during practice of the present invention is not objectionable
because the large particles readily break up in a screening
operation. After screening, the particle sizes are in substantially
the same range as originally produced and are still freely flowing
beads or globules.
The spray dried base particles are charged to the tumbling machine,
preferably a continuous tumbling drum, at one end thereof and, due
to the inclination of the drum, usually from 2.degree. to
15.degree., often 5.degree. to 10.degree., they pass through it
while continually tumbling so as to bring them in contact with
beads and overspray material. Because the beads are substantially
spherical and of rather large particle sizes, areas of contact
between the particles are not great and strong aggregates are not
formed. Yet, the liquid in the tumbler can be sorbed into the
interiors of the particles. Preferably, the spherules will be in
the 6 to 140 or 20 to 100 mesh range for best overspray results.
Throughput times in the continuous tumbler or a batch tumbler, if
that is employed, will usually be from 1 to 20 minutes, preferably
from 2 to 15 minutes and most often around 4 to 6 minutes. The
tumbling drum will rotate at about 2 to 30 revolutions per minute,
usually 4 to 10 r.p.m. for best treatments.
Along with the base beads may be added finely divided sodium
carboxymethyl cellulose or other anti-redeposition agents of
particle sizes that pass through a 200 mesh sieve, so that it is
dry mixed with the detergent base beads, usually before application
thereto of perfume or overspray nonionics. Other particulate
solids, such as builders and fillers, may be added together with or
at about the same locations in the drum as that at which the beads
are added. Usually, the different particulate solid materials added
are sufficiently mixed in the first 5 to 15 percent of the length
of the tumbling drum and after such point liquids may be added. It
is considered preferable to add the various solid components at the
upstream end of the tumbler in a continuous operation, so that the
liquid(s) are sprayed onto the dried mix. However, in variations of
the process successful products may be made by later additions of
particulate detergent components, in addition to additions of
"lubricant" or Satintone, which is best added at the end of the
drum or near the completion of tumbling.
Due to the rotation of the drum the particulate materials are
lifted upwardly along the upwardly rising drum wall and fall
downwardly before reaching the drum top, forming a continually
surface-changing section or particle screen against which the
liquid overspray may be directed. Thus, the overspray will normally
be aimed at such surface at an angle inclined from the vertical and
toward the surface. It will be apparent to one skilled in the art
how this angle should be adjusted to obtain most effective covering
of the particles with the liquid sprays. The most preferred
direction will be that in which the sprayed droplets, whether of
overspray material, perfume or other liquid, are directed onto the
most rapidly moving portion of the base particles in the tumbler
without contacting any quiescent sections of such particles and
without touching tumbler walls or parts. Of course, the sprays
should also avoid being directed at the inlets for the base beads,
CMC or other particulate or powdered materials and usually should
not be aimed at such incoming constituent streams.
The liquid droplets of sprays will normally be in the 50 to 500
micron diameter range, preferably 50 to 250 microns. Such very fine
particles tend to coalesce less and often a portion thereof will be
carried as a fog through at least the early part of the tumbling
apparatus, facilitating gradual contact with the base particles and
allowing penetration of the liquid overspray without causing
lumping or tackiness. The mass transfer of liquid overspray
nonionic detergent through the detergent base bead is important for
obtaining free flowing and non-tacky particles, and gradual contact
of finely divided liquid with quickly moving or tumbling base
particles allows the proper penetration of the liquid and
contributes to satisfactory production of a free flowing
product.
After tumbling for the desired time, the finished product is
removed and without any special cooling being required, is
packaged, following the procedure previously described, illustrated
in the drawing. Such packing takes place within 30 minutes or less
after removal of the product from the tumbling drum and when
packed, the beads, which may still be warm, are so retentive of the
overspray liquid (which may then still be in the liquid state,
inside the base particles) that the particles will not badly stain
an untreated cardboard carton at normal room temperatures. With
waxed, resin-coated or otherwise treated cartons, results will be
even better and the products will not cake, lump or become tacky on
prolonged storage. Thus, the nonionic is sorbed by the beads
sufficiently within the tumbling period to make the particles free
flowing and not sticky. Their "sorption coefficients" are high,
with from 2 to 20 percent of nonionic overspray being sorbed by a 6
to 200 mesh bead within 1 to 5 minutes. Flowability of the
particles will be further improved if they have dusted onto the
surfaces thereof 1/2 to 1 percent of a flow-inducing agent, such as
Satintone or other suitable powdered constituent, toward the
downstream end of the tumbler.
Within the proportions and conditions mentioned in this
specification useful oversprayed detergent products are
manufactured. A principal advantage of these products is in their
desired content of nonionic detergent. Although it is difficult to
spray dry any appreciable quantities of such compounds with other
components of a detergent composition, by following the present
methods a product is obtainable which is like a spray dried bead
and yet, contains the desired amount of nonionic. Pluming, the
production of bluish hazes over spray towers and the accompanying
smoke and air pollution are obviated. Of course, for best
processing and product results, the components, amounts thereof and
conditions of treatment will be modified within the ranges given.
For example, in compositions in which it is desired to include very
large quantities of silicate, in which, although 30 percent is a
usual upper limit, it might be wanted to extend to as much as 50
percent of the product in some instances, the very fact that
silicate inhibits penetration by the nonionic detergent militates
against more than 15 percent of the soluble silicate being included
in the crutcher mix. Thus, the remainder, in such a case, will
normally be separately produced in granular form and may be blended
in with the detergent base or oversprayed particles in the early or
late portions of the tumbling apparatus. Then too, if any CMC, NTA,
sodium sulfate or anionic detergent, such as linear alkyl benzene
sulfonate would be present in the base detergent in sufficiently
large quantities, or a combination thereof would be present in such
quantity, so that sorption of the nonionic would be inhibited,
portions of these materials might well be post-added. This is
especially true of the CMC since only a small quantity of that
material is tolerable in the crutcher mix without causing tackiness
in the product after post spraying. Additionally, materials which
aid penetration of the nonionic, such as sodium carbonate, might
well be increased in crutcher mixes which contain inhibiting
compounds, too. The amounts of lubricants or flow-inducing powder
such as Satintone should be increased if there is a danger that the
product will not flow well, due to content of too much of materials
which inhibit sorption of the nonionics. In a similar manner, the
rule of reason with respect to formulation is applicable to the
types of nonionic detergents that are employed. For example, where
there are present penetration-inhibiting materials, it may well be
preferable to utilize smaller quantities of the nonionics and the
nonionics might be of more or less fluid types, such as those of
lower or higher degrees of lower-alkoxylation. The more fluid
compounds penetrate the detergent base beads better and the less
fluid compounds do not migrate as readily to the surfaces of beads
of higher nonionic contents.
In the specification the terms minor, major, substantial,
substantially entirely and substantially all have been employed to
describe various concentrations or proportions of materials. As so
employed, minor means under 50 percent, major stands for more than
50 percent, substantial and substantially mean over 90 percent, and
substantially entirely and substantially all indicate over 98
percent.
Various advantages attending the practice of this invention are
unexpected and are significant. Thus, the fact that the liquid
nonionic detergent does not bleed from the detergent beads and make
them tacky is surprising. That detergent particles which resemble
spray dried detergents in their flowability are producible by this
method would not have been predicted. Rather, it would have been
expected that the beads would agglomerate, lose their spherical
outlines, increase in particle size and be of diminished flow
rates. Strangely enough, in most cases the bulk density of the
product does not change during treatment, nor does its particle
size distribution vary much from that of the starting material. It
might well have been anticipated that the addition of liquid
post-spray would cause a significant increase in bulk density of
the particles. That the process of overspraying should be so
efficient and so quickly effected is surprising, as is a noted lack
of criticality with respect to continuing the tumbling for
substantial periods of time, up to 30 minutes, after completion of
normal sorption of the overspray. It would normally be expected
that such additional tumbling would be detrimental to the detergent
bead but such is found not to be the case.
Other significant and surprising effects attending the present
invention include the use of hydrous silicate or other detergent
composition components which would normally tend to limit sorption
of nonionics on the detergent base particles, which use is effected
in such a manner as to limit their abilities to dissolve in the
crutcher mix before spray drying. Since it appears to be soluble
forms of such components which inhibit sorption of the nonionic
detergent, by adding them last, temporarily coating them with
protective agents, agitating for only a short period of time,
utilizing comparatively large particle sizes, etc., the
solubilities of such crutcher components are minimized and a
product is made which may usefully sorb nonionic detergents sprayed
thereon. Of course, the coating materials, particle sizes, etc.,
are chosen so that in final detergent use the added components will
dissolve and exert useful washing or adjuvant effects. The sorption
of nonionic detergent on the carbonate-containing beads appears to
be a combination of absorption and adsorption. Enough of the liquid
penetrates to the interior of the bead to prevent it from being
unduly wet and the nonionic on the surface appears to be held there
so that it does not cause particles to stick together. Whatever the
mechanism of sorption, the significant result obtained is a
free-flowing product which may be high in nonionic detergent
content.
Although the nonionic content may range from 2 to 20 percent,
usually, if the nonionic detergent is the only detergent present
and is mostly or entirely in the overspray, the limit thereon will
be about 15 percent. It has been found that 16 percent can be
incorporated in a freely flowable product if the detergent beads
are fresh, that is at a temperature of 27.degree.to 43.degree.C.
and less than 2 hours old, preferably less than 30 minutes and most
preferably, less than 5 minutes old. Such beads sorb the nonionic
better, whereas if they are allowed to stand for a day, addition of
lubricant (Satintone) is desirable to maintain the free flowing
nature of the product. By the present method, spray dried and
oversprayed products high in nonionic detergent content may be made
and products in which the active organic detergent is a mixture of
anionic and nonionic, totaling about 14 percent and about equally
divided between the two types of organic detergents, may be made,
although such formulas cannot be spray dried economically from
crutcher mixes.
A surprising aspect of the present invention is in the free flowing
nature of the recently oversprayed detergent particles. Despite
their contents of silicate, sulfate, anionic detergent and
sometimes, anti-redeposition gums, all of which act to slow down
sorption, because of the presence of sodium carbonate and the
adherence to formula restrictions given, quick sorption is
obtainable. Thus, product may be packed immediately after removal
from the overspraying apparatus whereas, for formulas outside the
described ranges which also contain sorption-inhibiting agents, a
curing period of about a day is required. A 24 hour holdup of all
the produced detergent requires huge storage facilities plus
transporting equipment, all of which are unnecessary when the
present invention is followed. For compositions outside the present
invention which are not satisfactorily aged to
EXAMPLE 1 ______________________________________ Parts by weight
______________________________________ Water 267.0 Sodium linear
higher alkyl* benzene 125.0 sulfonate** detergent base, 56% solids
aqueous slurry Sodium sulfate, anhydrous 250.0 Fluoroescent
brightener (Stilbene No. 4) 4.0 Fluorescent brightener (ALF) 1.0
Antioxidant 0.3 Sodium carbonate, anhydrous 85.0 Sodium silicate
(Na.sub.2 O:SiO.sub.2 = 1:2.3), 231.0 43.2% solids aqueous solution
Pentasodium tripolyphosphate, anhydrous 330.0
______________________________________ *C.sub.12.sub.-15, averaging
about C.sub.13.5. **87.5% active ingredient, the balance being 10%
sodium sulfate and 2.5% unreacted oil (alkyl benzene). suitable for
passing through filling equipment, lazy movements thereof often
cause only partial fills of cartons and sometimes result in jamming
of the filling equipment. Another important advantage noted for the
products of this invention is that the fluorescent dye or optical
brightener incorporated in the crutcher mix, when the detergent
particles containing it are oversprayed, whitens the product much
more than the same amount of dye in a product which has not been
oversprayed. It appears that the nonionic overspray material
encourages migration of the fluorescent dye to the surfaces of the
beads, increasing their concentrations at the bead exteriors. Such
a mechanism can also be useful in maintaining concentrations of
perfumes and similar adjuvant materials higher at the outside of
the detergent particles than in the interior, giving it a greater
appeal to the consumer or allowing a saving in the quantity of
perfume employed. It has also been theorized that the nonionic
detergent may also improve the transparency or translucency of the
surface of the particles, thereby better enabling the optical
brighteners to whiten the product.
In addition to the mentioned unexpectedly beneficial results, the
present processes and formulations allow the making of excellent,
free flowing detergent products by efficient and practicable means,
utilizing available equipment and actually improving its
capacity.
The following examples illustrate the invention but should not be
considered as limiting it. Unless otherwise mentioned, all
temperatures are in .degree.F. and all parts are by weight.
T,380
The listed components of the 65 percent solids crutcher mix for
making the detergent base are sequentially added to a crutcher and
are mixed therein for about 15 minutes, with the final temperature
of the mix in the heated crutcher becoming about 185.degree.F. The
mix is then pumped to a spray drying tower of the countercurrent
type, spray dried to base beads and the beads are tumbled while
overspraying materials are applied to them, after which they are
packaged. The method followed is in accordance with the drawing.
However, it should be understood that operations and equipment not
essential for the practice and understanding of the invention have
been omitted from the drawing and from this description in the
interest of simplicity of presentation.
The crutcher mix is pumped to the spray tower by a positive
pressure pump which produces about 800 pounds gauge pressure at a
manifold before the spray nozzle. A single No. 2-15 Whirljet spray
nozzle is used to spray the crutcher mix into the top of the 60 ft.
high, 8 ft. diameter tower. The inlet air temperature to the tower
is 450-500.degree.F. and the outlet temperature is about
400.degree.F. The slurry enters the spray nozzle at about
180.degree.F. Residence time of the droplets and particles in the
tower is about 1 to 4 minutes. The product is withdrawn at the
bottom of the tower and is air lifted to a bin from which it is
dispensable to a mixing drum or twin shell blender, in which the
overspraying operation is effected. Extensive experimentation has
shown that the actions of batch and continuous tumbling drums and
twin shell blenders are substantially equivalent, with respect to
the characteristics of the products produced. Accordingly, in
commercial operations the continuous inclined drum tumbler will
usually be employed because it produces a satisfactory product and
often has a much higher throughput rate than corresponding batch
tumblers or blenders.
The spray dried detergent base beads, of particle sizes in the 6 or
8 to 140 or 200 mesh range, a substantial proportion of which is in
the 6 to 100 range and the major proportion of which is in the 6 to
80 mesh range, have a moisture content of about 10 percent, upon
being charged to the tumbling apparatus. They are of a density of
about 30 lbs. per cubic foot and a temperature of about
80.degree.F. to 120.degree.F., when charged.
To a continuous tumbling drum like that illustrated in the drawing
are added, within a half hour of manufacture and in many instances,
within 5 minutes, about 90.5 parts of the base bead, including
about 9 to 10 percent moisture, 2 percent of powdered CMC and 7.5
percent of Neodol 45-11. At the temperature of addition, about
90.degree.F., the Neodol 45-11 has a viscosity of about 68
centipoises. No perfume, enzymes or Satintone or other
flow-improving agent is utilized in this run but such may be added
at the points previously described in the specification, if
desired. The CMC employed is finely powdered, passing through a 100
mesh sieve and with substantially all passing a 200 mesh sieve. It
is added in the beginning portion of the tumbling drum by a
metering device and is substantially mixed with the detergent base
beads in the first 5 to 15 percent of the length of the tumbler.
The tumbler is operated at about 25 r.p.m. and blending takes about
4 to 8 minutes, with the initial 30 seconds being allowed for
blending the CMC with the base beads. The Neodol 45-11 is sprayed
into the mixing drum in spherical particles approximately 50 to 100
microns in diameter, which are directed against a wall of falling
detergent beads. The spray is made by using a Spray Systems Inc.
round spray cone atomization nozzle at an air pressure of about 40
lbs./sq. in. gauge. After completion of mixing the beads are
withdrawn and are immediately packaged (within a minute) in
carboard cartons, which are sealed and sent to storage.
The product made is an excellent household laundry detergent for
use in automatic washing machines. It has a flow rate of between 60
and 70 percent, which is good. (See out application entitled
MANUFACTURE OF FREE FLOWING PARTICULATE DETERGENT CONTAINING
NONIONIC SURFACE ACTIVE COMPOUND, filed Mar. 15, 1971, which is
incorporated by reference herein, for additional information on
flow rate tests and other procedures, ingredients, processes,
etc.). The final product is also found to be non-tacky and does not
pack or lump objectionably. Its bulk density is about the same as
that of the starting detergent base beads.
The above overspraying method utilizes a tumbling drum like that
shown in the drawing but when a batch operation is desired to be
effected, the same equipment may be used, except for the
installation of baffles to maintain good mixing throughout the
drum, the changing of the angle of the drum from about 3.degree. to
about 0.degree. and the more central addition of materials and
overspray thereon, to obtain equally good results. Similarly,
continuous or batch twin-shell blenders, with and without breaker
bars, and equipped with internal sprays, may be used to obtain such
results. However, for speediness and ease of manufacture and
control of product quality, the continuous drum blender illustrated
is preferred.
By the method of this example there is produced a built detergent
composition containing approximately equal amounts of anionic and
nonionic detergent and with the total content thereof at about 14
percent. Such a formula cannot be produced by spray drying only,
without waste of nonionic and violation of anti-pollution codes,
due to the pluming of the nonionic from the spray tower. Yet, by
the present method, a free flowing, high quality product results
with little extra processing and without producing the
objectionable plume.
In formulas of this type, when the proportion of soda ash is
increased, replacing the sulfate, the products made are not as
freely flowing as those wherein the sulfate is present with the
soda ash. This result for anionic-nonionic detergents is different
from that noted for all-nonionic products. In both cases the
presence of sodium carbonate is very helpful in producing a free
flowing and non-tacky product.
An important advantage noted is that the overspraying of the
nonionic detergent results in a whiter or brighter product,
apparently due to an effect of the overspraying on the content of
fluorescent dyes or optical brighteners in the base beads, whereby
they are attracted to near the beads' surfaces.
Instead of Neodol 45-11 in the overspray, other Neodols within the
description given may be used, either in replacement of the Neodol
45-11 or together with it, to obtain similar results. In a like
manner, replacement may be with Plurafac B-26 or Alfonic 1618-65
and a good product will be obtained. A small proportion, preferably
no more than 0.2 percent of CMC or other antiredeposition agent
(most preferably, none) may be present in the crutcher without
interfering with the overspraying operation. Builders and fillers
may be employed in place of those shown. Thus, 10 percent of borax
may be used in place of some of the tripolyphosphate and 5 percent
salt may replace some of the sulfate. The silicate may be replaced
in whole or in part by other metasilicates of Na.sub.2 O:SiO.sub.2
ratio of 1:2 or 1:2.6 and hydrosilicates may be employed as such a
replacement to the extent of about 3.5 percent in this formula.
Other anionic detergents, including sodium lauryl sulfate and
sodium coco-tallow soaps, and other nonionics, including nonyl
phenoxy polyoxy ethanols (Igepal CA-630) may replace a part of the
respective anionic and nonionic detergents, to the extent of about
3 percent, without changing the characteristics of the product
greatly. In a similar manner, the proportions of the various
constituents may be altered, as may be the processing temperatures,
times, etc., within the scopes described in the specification. When
the proportions are changed about .+-. 20 percent, the product
resulting has properties essentially the same as those of that
described.
Particle size of the detergent base beads to be sprayed has a
bearing on flowability of the oversprayed detergent. Thus, when
particle sizes are in the 60 to 200 mesh range flowability will be
descreased, compared to a similar product in the 6 to 60 mesh
range. However, even with the smaller particles, the products of
the present formulas and treatments will be superior to those not
containing the carbonate and silicate or which are manufactured by
ordinary powder mixing methods. Also, although when ordinary
detergent compositions, containing no carbonate, are post-sprayed
with nonionic, it may be possible to add as much as 5 percent of
nonionic to the product, providing that no CMC at all is present in
the crutcher, the silicate content is kept low and the product
sprayed is a spray dried product of large bead size, even in such
situations products made according to the invention are superior in
flowability when of the same bead sizes.
EXAMPLE 2 ______________________________________ Parts by weight
______________________________________ Water 130.0 Fluorescent
brightener (Stilbene No. 4) 2.0 Fluorescent brightener (ALF) 0.5
Antioxidant 0.3 Sodium carbonate, anhydrous 310.0 Sodium silicate
(Na.sub.2 O:SiO.sub.2 = 1:2.32), 116.0 43.2% solids aqueous
solution ______________________________________
Water, fluorescent brighteners, antioxidant, sodium carbonate and
sodium silicate are added sequentially to a heated crutcher and the
procedure described in Example 1 is followed. In the tumbling
apparatus there is mixed with spray dried base detergent beads,
which are of hollow, substantially globular form and analyze about
10 percent moisture, 3 parts of sodium carboxymethyl cellulose per
82 parts of beads and there is then sprayed onto the surfaces of
the tumbling beads 15 parts higher alkoxy polyethoxy ethanol
(Neodol 45-11). The product taken off, a low sudsing built nonionic
detergent, containing 15 percent of the nonionic detergent
material, is in flowable form and is not tacky. It does not lump in
the carton on ordinary storage at the usual room temperatures.
However, when the temperature is raised to about 120.degree.F. for
any period of time, some staining of the nonionic detergent onto
container walls may be noted. When products are to be stored at
such temperatures, barrier linings will usually be employed in the
cardboard boxes. When larger quantities of nonionic overspray
material, within the range of this invention, are employed, it may
be desirable to utilize a flow-aiding agent, such as Satintone, or
other suitable powdered clay product, to improve flowability and
diminish any minor tendency to tackiness.
In additional experiments it has been noted, with respect to the
essentially inorganic spray dried base bead, that best sorption of
nonionic is obtained when the moisture content of the bead is from
0.5 to 5 percent and the particle sizes are in the 6 to 80 mesh
sieve size range.
EXAMPLE 3
Following the procedure described in Example 1, there is produced
an essentially inorganic spray dried detergentbuilder composition
comprising 15 parts sodium carbonate, anhydrous; 33 parts sodium
tripolyphosphate; 18 parts sodium sulfate, anhydrous; 10 parts of
sodium metasilicate of a Na.sub.2 O:SiO.sub.2 ratio of about 1:2.3;
and 10 parts of water. To this, in the described tumbling drum are
added by overspraying 10 parts of higher alkoxy polyethoxy ethanol
wherein the higher alkoxy is mixed C.sub.14 and C.sub.15 and the
ethoxy ethanol content is such that it contains about 22 carbon
atoms, and 2 parts of dicocoyl amine. The dicocoyl amine (Armeen
2C, made by Armour Chemical Company), is first melted and blended
with the liquid nonionic higher alkoxy polyethoxy ethanol, after
which the mixture is sprayed onto the detergent base beads, which
are of particle sizes that pass through an 8 mesh U.S. Standard
Sieve Series sieve and rest on a 140 mesh sieve.
The dicocoyl amine is useful in these compositions as an
anti-foaming agent and prevents any foaming at all of the product.
Instead of utilizing 2 percent, in similar experiments 1 percent
has been incorporated with the nonionic detergent and 2 percent of
sodium coco-tallow soap (85:15) replaces 2 percent of the sodium
sulfate in the spray dried beads. When the dicocoyl amine or other
higher alkyl amine anti-foam agent is added in the crutcher, it is
usually destroyed or lost during the spray drying process. When it
is added separately in the tumbling drum, it causes tackiness and
sticking of the product. However, by following the method of this
example, a good free flowing, non-tacky, non-foaming product is
obtained.
In changes of the formula and process, the proportions of nonionic
are varied from 5 to 15 percent, with the obtaining of similar
improved results. The proportion of dicocoyl or other dialkyl amine
may be varied over the range of 0.5 to 4 percent but usually 1 to 2
percent will be used. Similar changes in the contents of sodium
carbonate, sodium tripolyphosphate and sodium sulfate may be made
within the ranges described in the specification, and the moisture
content may be adjusted in like manner. With respect to sodium
silicate content, it will normally be undesirable to increase this
above 15 percent, unless it is post-added, or hydrous silicate or
some other form of "unreactive" silicate, which does not prevent
sorption of the nonionic, is employed in the crutcher mix, such
employment being in a manner to prevent its dissolving before
intended final use. When the hydrous or other metasilicate is added
to the tumbling drum it yields best results and most free-flowing
product, with a minimum of tailings, especially when the silicate
granules employed are in the 8 to 140 mesh range.
To improve the anti-redeposition properties of the product, about
0.5 to 5 parts of sodium carboxymethyl cellulose are added,
sometimes with from 5 to 10 parts of granular hydrous silicate, in
the tumbling drum.
Although good results are obtainable when the nonionic
detergent-DCA blend is applied at slightly elevated temperataures
(it is desirably made by first heating to 60.degree. to
70.degree.C. and blending the components), in many applications,
such as that described herein it will be more desirable to heat
this mix to a temperature of 50.degree.-70.degree.C. before
spraying.
The density of the product made is about 0.7, a little higher than
the preferred 0.3 to 0.6 g./cc. range but this can be lowered by
utilizing different spray nozzles and larger particle size beads.
The density is only very slightly greater than that of the base
beads employed. The final product has an excellent flow rate, being
76 percent by the flow test employed.
EXAMPLE 4
In a manner similar to that followed in Example 3, a base bead
comprising 2 parts of sodium coco-tallow soap (approx. 85:15); 50
parts soda ash; 10 parts sodium metasilicate (1:2.3 Na.sub.2
O:SiO.sub.2 ratio); 10 parts of water and 15 parts hydrous sodium
silicate, added last to the crutcher mix, just before spray drying,
is prepared by crutching and spray drying to hollow globular beads
of the size range previously described in Example 3. Then, 0.5
percent of sodium carboxymethyl cellulose is admixed with the beads
in the tumbling drum and a mixture of 12 parts of Neodol 45-11 and
1 part of Armeen 2C is sprayed onto the tumbling beads. The beads
are at approximately room temperature and the liquid being sprayed
is initially at a temperature of about 65.degree.C. At the end of
the tumbling drum is added 2 percent of Satintone flow-improving
agent. Although the product is not as free flowing as many of the
formulations containing lesser proportions of silicate, it does
flow fast enough to be fillable into cartons by automatic filling
equipment, without undue bridging or blocking of passageways, which
would otherwise cause holdups in the filling line. When a lesser
amount of flow improving additive is used the flow test results are
poorer, as would be expected.
Contrary to the results obtained in Example 3, the densities of the
products of this experiment are in the 0.2-0.3 g./cc. range and the
flow rates are less than those of the spray dried beads charged to
the tumbling drum. When the blending times are varied over the
range of 3 to 10 minutes the physical properties of the product are
not significantly altered. Similar results are obtainable when
larger quantities of sodium carboxymethyl cellulose are used, from
0.6 to 3 percent, and when a portion of the soda ash is replaced by
15 parts of sodium sulfate and the hydrous silicate is replaced by
sodium tripolyphosphate. Also, the addition of 0.1 to 2 percent of
fluorescent brightener in the crutcher mix (preferably replacing
some of the silicate) and the spraying on of 0.1 to 1 percent of
perfume in the tumbling drum do not change the properties of the
product. It is noted that the post treatment of the spray dried
beads improves the whiteness thereof, apparently due to the
fluorescent dye being aided in migrating to the beads'
surfaces.
Although additional experimentation is being conducted to find
better ways of adding the hydrous silicate in the crutcher so that
the proportion thereof dissolving may be diminished, a preferred
method at the present is to add the hydrous silicate in the
tumbling drum as granules of approximately the same particle size
distribution as the spray dried beads. It has been found that the
less chance there is for dissolving of the hydrated silicate, the
more free flowing the product. Certainly in postadding the silicate
to the tumbling drum the dissolving is minimized.
When instead of 10 parts of hydrous silicate being added in the
crutcher, 30 parts thereof are added in the tumbling drum, with the
porportion of soda ash being diminished from 50 to 30 parts, the
product obtained has a density of about 0.35, up from 0.25 for the
base beads, and the flow rate is 57 percent, down 8 percent from
the base beads. However, by addition of 1 percent of Satintone in
the tumbler on the downstream end thereof the flow rate is
increased to 65 percent, which is highly acceptable, and the
density is still about 0.35.
EXAMPLE 5 ______________________________________ Parts
______________________________________ Sodium tripolyphosphate 33
Soda ash 10 Sodium metasilicate (Na.sub.2 O:SiO.sub.2 = 1:2.3) 10
Sodium sulfate, anhydrous 22 Linear tridecyl benzene sulfonate,
sodium salt 7 Higher alkoxy polyethoxy ethanol (Neodol 45-11) 2
Fluorescent brightener, Stilbene No. 4 0.6 Fluorescent brightener,
Stilbene No. 3 0.06 Fluorescent brightener, Tinopal RBS 0.06
Oxazole fluorescent brightener ALF 0.4 Water 9
______________________________________
The above composition is sprayed from a 60 percent solids aqueous
crutcher mix in a spray tower like that described in Example 1 and
in accordance with the method mentioned therein. While still fresh,
at a temperature of about 110.degree.F., the detergent composition
base beads, of hollow globular form and of particle sizes in the 6
to 140 mesh range, are fed by the illustrated apparatus, a weigh
belt feeder, to an 18 ft. long rotary drum or cylinder, having a
diameter of about 21/2 ft. 0.85 Part of sodium carboxymethyl
cellulose is also fed to the tumbling drum, through the same chute
as the detergent base beads, with the feed of base beads varying
from 94 to 87 parts. 0.15 Part of detergent perfume is blended with
7 parts of Neodol 45-11 and from 5 to 12 parts of this mixture,
heated to 140.degree.F., is sprayed into the tumbling drum onto the
detergent beads, as illustrated in FIG. 3, except for no separate
perfume spraying. The ratios of base + CMC to Neodol 45-11 +
perfume are varied from 95:5 to 88:12.
Tumbling in the drum, which rotates at about 16 r.p.m. takes place
at about room temperature, approximately 80.degree.F., with about
130 lbs. of mateial in the drum at any time, a residence time of
about 7 minutes and a throughput of about 16.5 pounds per foot and
hammers are employed to keep material from adhering to the side
thereof.
The products obtained are of a density of 0.5 to 0.6 g./cc., flow
well and are not tacky. No Satintone or other lubricants are needed
to promote flow. In the detergent beads manufactured, there are
present 7 percent of anionic detergent and from 7 to 14 percent of
the nonionic detergent.
The product produced is brighter appearing than the base beads,
despite the fact that there is a lower content of fluorescent
brighteners in the post-sprayed detergent. The particle sizes of
the detergent are about the same as those of the base beads charged
to the tumbling drum.
When the amount of sodium tripolyphosphate is reduced to 23 percent
and the soda ash is increased to 20 percent, an even better flowing
detergent is made. Similarly, when the Neodol 45-11 is omitted from
the crutcher mix and is replaced by sodium sulfate, better sorption
of the nonionic overspray results. In some embodiments of the
invention, fluorescent brighteners or portions of the fluorescent
brightener charge are mixed in with the overspraying materials to
produce brighter detergent beads. When part of the
tripolyphosphate, e.g., 10 percent thereof, is post-added, together
with an additional proportion, e.g., 10 percent of the sodium
metasilicate, perferably as hydrous sodium silicate, leaving the
base beads providing 23 percent of the sodium tripolyphosphate and
12 percent of the anhydrous sodium sulfate, good detergent products
which are free flowing and non-tacky also result.
EXAMPLE 6
A series of detergent compositions is made substantially in
accordance with the method described in Example 1 and the flow
rates and densities of the products made are recorded. The products
include 10 percent of sodium silicate (Na.sub.2 O:SiO.sub.2 =
1:2.3), 7 percent of linear higher alkyl benzene sulfonate, sodium
salt, and 7 percent of higher alkyloxy polyethoxy ethanol (Neodol
45-11). Variations in the base bead composition and in the final
product formulas are explored to determine their effects on
flowability of the detergent beads produced. With 66 percent (all
percentages are on a final product basis) of soda ash and 0.5
percent of sodium carboxymethyl cellulose in the crutcher with the
silicate and linear tridecyl benzene sulfonate, flowability is poor
after post-spraying onto the base beads of the 7 percent of Neodol
45-11. However, when the sodium carboxymethyl cellulose is omitted
from the formulation and the soda ash content is increased to 67
percent, the flow is 62 percent, which is highly acceptable.
Densities of the products are 0.35 and 0.45, respectively. When the
crutcher mix comprises 66 percent sodium sulfate, 10 percent
silicate, 7 percent of the anionic detergent and 0.5 percent of
CMC, the flowability is 0, as is also the case when the CMC is
omitted. With 33 percent of tripolyphosphate, 34 percent of sodium
sulfate, 10 percent of sodium silicate and 7 percent anionic
detergent, flowability is 0 but when the sulfate is replaced by
soda ash, flowability increases to 68 percent. For a 33 percent
TSPP, 10 percent silicate and 7 percent anionic detergent bead,
containing from 8.5 to 25 percent of sodium sulfate and from 25 to
8.5 percent soda ash, excellent flows are obtained. Such results
also obtain when the TSPP is replaced with TPP. Similarly, when 1
or 2 percent of Neodol 45-11 and/or 1 or 2 percent of soap is
present in such formulations, good flows are obtained except in the
simultaneous presence of soap and the absence of Neodol 45-11 and
sodium sulfate from the base bead. When 20 percent of sodium
citrate is added to such formulations, in replacement of some of
the TPP, so that TPP content is dropped to 15 percent, flow is
good, providing that 1 or 2 percent of Satintone is present. When
an 80 percent soda ash, 15 percent silicate and 5 percent moisture
bead is made, later blended with 1 percent CMC and oversprayed with
10 percent Neodol, a flowable detergent results.
A wide variety of other experiments is conducted, varying the
proportions of the constituents within the ranges described in this
specification, and good detergents which are free flowing,
non-tacky and stable are obtained. Such is also the case when
processing conditions are changed within the ranges given with
respect to temperatures, times, speeds, type of tumbling employed,
etc. The conditions to employ will be clear to one of skill in the
art, following the specification. No extensive experimentation to
determine formulas and processes will be necessary.
The invention has been described with respect to working examples
and illustrations thereof but is not to be considered as being
limited thereto, since equivalents and substitutes may be employed
within the inventive concepts.
* * * * *