Note: Descriptions are shown in the official language in which they were submitted.
~ 3L~5
FABRIC CONDITIONING COMPOSITIONS
Andre' Cesar Baeck
Young Sik Oh
The present invention relates to granular fabric conditioning
compositions. More specifically it relates to compositions
containing a fabric-softening amount of a hector;te clay, the clay
being in the form of particles having a narrowly-defined layer
charge distribution and preferably having a high level of
deposition upon fabrics.
British Pztent 1 4()0 898, published July 23, 1975, discloses detergent
compositions comprising~ as a fabric-softening ingredient, a smectite-type clay.Any smectite-type clay having a cation exchange capacity of at least 50 meg/
100 g is taught to be suitable. Gelwhite GP and Volclay BC, both of which are
soclium montmori~lonite clays, are disclosed to be preferred for reasons of color
and cation exchange capacity.
It is now well recognized in the detergent industry that
clays of the type disclosed in British Patent 1 400 898 provide
significant fabric softening benefits when used in a laundry
detergent. Yet, it is equally well recognized that deposition of
these clays onto the fabrics during the laundering process is far
from complete; in fact, under typical European laundry conditions,
less than half of the available clay is deposited onto the
fabrics, the remainder being rinsed away with the laundry liquor
during the subsequent rinsing steps. Moreover, the softening
effect obtained as a result of the clay deposition is affected by
factors that are not well understood.
It is an object of the present invention to provide granular
fabric conditioning compositions that can be added to the laundry
during a rinse stage of the laundry process comprising a fabric
softening clay from which the clay particles are more efficiently
deposited onto fabrics during the laundry process. It is further
object of this invention to select clay materials for use in
conditioning compositions that provide a significantly better
fabric-softening performance than the clay materials used to date
in commercial detergent and other fabric conditioning
compositions.
SUMMARY OF THE INVENTIO~
The present inventiorl relates to granular fabric conditioning
compositions containing a hectorite clay for addition to laundry
loads in the rinse stage, as opposed to the wash stage wherein
detergent ingredients are typically pr~sent in substantial
amounts. The clay is in the form of agglomerates. The clay has a
narrowly defined layer charge distribution, such that at least
about 50% of the clay has a layer charge of from about 0.23 to
about 0.31. Preferably the compositions of the present invention
exhibit Relative Depositions of at least about 2.5.
DETAILED DESCRIPTION OF THE INYENTION
The fabric conditioning compositions of the present invention
contain from about 10% to about 99% of the fabric so-ftening clay
described below, and from about .5% to about 40% of a
binding/dispersing agent. The clay is in the form of an
agglomerate. The composition may optionally contain other fabric
conditioners, perfumes, dyes or other ingredients useful for
fabric conditioning compositions. These agglomerated particles
should not contain detersive ingredients, such 3S surfactants,
builders, clay soil removers, enzymes, and the like, in
sufficiently large quantities to significantly interfere with the
rinsing process. The agglomerated clay particles may contain low
amounts of ingredients such as surfactants, builders, and the like
which can aid in dispersing the clay in the rinse. Generally,
less than about 30%, by weight of the agglomerate, of such
compounds will be present, preferably less than about 15%, more
3~ preferably less than about 10%. The clay, utilized in the present
invention which is of the smectite-type, is selected on basis of
its layer charge properties. The hectorite clays of natural
origin, suitable for the detergent compositions of the present
invention, have the general formula:
, ,~',,
[(M93 XLiX) Si4~yMeIIIyolo(oH2-zFz)]-(x+y)(~ + Y)Mn+
wherein y = o; or, if y f o, MeIII is Al, Fe, or B: Mn~ js a
monovalent (n = 1) or divalent (n = 2) metal ion, for example
sele~ted from Na, K, Mg, Ca, Sr. The value of (x ~ y~ is the
layer charge of the hectorite clay. The hectorite clays suitable
for the detergent compositions of the present invention have a
layer charge distribution such that at least 50% is in the range
of from 0.23 to 0.31.
Preferred are hectorite clays of natural origin ha~ing a
layer charge distribution such that at least 65% is in the range
of from 0.23 to 0~31.
The layer charge distribution of the clay material can be
determined using its swelling in the presence of cationic
surfactants having specific chain lengths. This method is
described in detail by Lagaly and Weiss, Zeitschrift fuer
Pflanzenernaehrung und Bodenkunde, 130(1), 1971, pages 9-24, the
disclosures of which are incorporated herein by reference.
The hectorite clay is provided in the composition of the
present invention as free-flowing agglomerates of clay. The
agglomerates can comprise smaller particles of clay such as are
commercially available in the industry. Typically, the particles
. Wi 11 be from about 1 micron to about 50 microns. The clay
agglomerates can also be made in the desired size range (discussed
below) directly from an aqueous clay slurry by spray drying or
other techniques known in the art. ~he agglomerates should have a
median diameter of from about 75 microns to about 2000 microns,
preferably a median diameter of from about 100 microns and about
1250 microns, most preferably from about 300 microns to about 1000
microns. The clay asglomerates are preferably screened so as to
separate agglomerates less than about 75 microns, preferably less
than about 100 microns, and greater then about 2000 microns,
preferably greater than about 1250 microns.
2~
It is an essential aspect of this invention that the clay
agglomerates contain, in addition to the clay, a
binding/dispersing agents as described hereafter. It has been
found that the clay, when agglomerated and added to the rinse
5stage of an automatic washing machine without presence of such
binding/dispersing agent, does not provide well-distributed
deposition of the clay upon the fabrics. Rather, the clay tends
to further agglomerate at the surface of the rinse water and
deposit upon the fabrics with poor distribution. It is important
10for obtaining even deposition that the clay agglomerates sink or
otherwise remain below the surface of the rinse water during the
rinse stage and, further, become well-dispersed prior to the end
of the rinse stage. Typically, the rinse stage of an automatic
washing machine will be between about 2 and about S minutes.
15Agglomeration methods and equipment suitable for use include
those methods known in the art. Non-limiting examples of the
eq~ipment suitable for agglomeration of clay from smaller
particles include a Dravo pan agglomerator, KG/Schugi
Blender-Granulator, whirling knife continuous vertical fluidized
20bed agglomerator. Niro Fluidized Bed agglomerator, Obrian
Mixer/Agglomerator, and a Littleford mixer (Littleford Brothers,
Inc., Florence, Kentucky, USA, eg. Model FMI30D).
Other methods and equipment which use larger amounts of
water, including the manufacture of agglomerates (as defined
25herein) directly from a clay slurry, include a spray drying tower,
and a prilling tower.
On a laboratory scale, food processors which are widely
available to the general public can be used to agglomerate smaller
clay particles into agglomerates in the disclosed size ranges.
30In making the clay agglomerates, an aqueous mixture of water
and the binding/dispersing agent can be first prepared and slowly
added to the clay while the clay is subjected to the mechanical
agitation of the agglomeration equipment. Once agglomerated, the
clay can be dried, but should not be over-dried. Overdrying can,
35as will be understood by those skilled in the clay art, lead
.
.
. .
- 6 -
to reduced ability of the clay to disperse. Drying at ambient
temperatures unaided or aided by fsrced air provides acceptable
' drying levels.
Preferred binding/dispersing agents are water-soluble
inorganic salts. These can include sodium carbonate, sodium
sulfate, potassium carbonate, potassium sulfate, magnesium
sulfate, lithium sulfate, lithium carbonate, sodium citrate, and
sodium sesquicarbonate. Preferred are sodium sulfate and sodium
carbonate. Without limiting the invention, it is theorized that
salts such as sodium carbonate which are basic in character are
particularly advantageous for the present compositions. ~hese
water soluble inorganic salts are believed to act as binding
agents which impart a temporary bind;ng force that facilitates
agglomerate integrity for a sufficiently long period after being
added to the rinse stage of an automatic washing machine such that
the agglomerates can slnk or rema;n below the surface of the
water. ~owever, importantly, since the salts are water soluble,
the binding force dissipates during the rinse stage so that the
clay agglomerates can hydrate and disperse, to thereby facilitate
even distribution of the clay upon the fabrics in the washing
machine. Additionally, the salts are of relatively high density
and inclusion of the salts into the agglomerates can aid with
increasing the agglomerate density. Excessive compression of the
clay to achieve the desired density can inhibit dispersion. The
agglomerates preferably have a density of greater than about 1.0
g/cc. The agglomerates typ~ically will contain from about 1% to
about 40%, preferably from about 5% to about 35~/O~ more preferably
from about 10% to about 35% of a water -soluble ;norganic salt,
based upon the total weight of the agglomerate.
Another type of binding/dispersing agent that and be used,
alone or in combination with a water insoluble inorganic salt, is
.~
:
.
.. ..
~6~0 ~3L6~
a dispersing aid. Dispersing aids that can be used can generally
include surfactants. These include surfactants com~only use as
detersives in 1aundry detergents (though they will be present in
substantially lower concentrations when added to the rinse stage
as part of the present compositions). lhe surfactants suitable
for use can comprise an anionic, nonionic, ampholytic or
zwitterionic surfactant or a mixture thereof. Nonionic
surfactants, or other surfactants, that can interfere with clay
deposition should be used in low amounts only, preferably less
IO than about 10% of the weight of the agglomerate. Anionic
surfactants are preferred. Typical anionic surfactants are the
alkyl benzene sulfonates, alkly- and alkylether sulfates, paraffin
sulfonates, olefin sulfonates, alkoxylated (especially
ethoxylated) alcohols and alky phenols, am;ne oxides,
alpha-sulfonates of fatty acids and of fatty acid esters, and the
like, which are well known from the detergency art. In general,
such surfactants contain an alkyl group in the Ca-C26 range, more
generally in the C8-CIa range. The anionic surfactants can he
used in the form of their sodium, potassium or triethanolammonium
salts: Anionic phosphate surfactants are also useful in the
present invention. These are surface active materials in which
the anionic solubilizing group connecting hydrophobic moieties is
an oxy acid of phosphorus. The more common solubilizing groups,
of course are -SO~H and -SO3H. Alkyl phosphate esters such as
(R--0)2PO2H and ROPO3H2 in which 2 represents an alkyl chain
containing from about 8 to about 20 carbon atoms are useful
herein. Suitab1e nonionic surfactants useful in the present
invention include those obtained by the condensation of one to
twelve ethylene oxide moieties with a C10-C~8 aliphatic alcohol.
The alcohol may be completely linear as occurs in materials
derived from the natural feedstocks such as vegetable oils and
animal fats, or may be slightly branched as occurs in petroleum
derived alcohols made by oxo-type synthesis. Other nonionic
materials are Cl~-CIs alcohol condensed with an average of seven
ethylene oxide groups. Cl2-CI3 alcohol condensed with an average
of about four ethylene oxide groups and then subjected to
stripping to remove unetnoxylated and low ethoxylated materials,
to leave an ethoxylated having a mean of 4.5 ethylene oxide
groups. Suitable zwitterionic materials include derivatiYes of
quaternary ammonium compounds containing an aliphatic straight
chain group of 14-18 carbon atoms and a sulfate or sulfonate
anionic solubilizing group. Specific examples include 3-N,
N-dimethyl~N-hexadecylammonio-2-hydroxpropane-1-sulfonates;
3-(N,N-dimethyl-N-tallowylammonio)-2-hydroxypropane-1-sulfonate;
3-(N,N-dimethyl-N-tetradecyl amonio)-propane-lsulfonate; and
6-(N,H-dimethyl-N-hexadecylammonion)-hexanoate.
The preferred composition of the present invention ~ill
contain at least about 10%, more preferably at least about 20%,
most preferably at least about 40%, of a bind;ng aid as defined
above, and optionally contain about 1% to about 10% a dispersing
aid.
When the clay agglomerates are made from clay slurry, the
binding/dispersing agent can be added and mixed with the slurry
prior to formation of the clay into relatively small particles by,
for example, prilling or spray drying. These particles can then
be agglomerated into the agglomerate range defined above.
Alternately, agglomerates encompassed by said size range can be
formed directly from the slurry by the same general processing
methods. In the former case, the particles are preferably
agglomerated with the use of an aqueous solution which contains
more of a binding/dispersing agent.
Recently, a method has developed for objective assessment of
fabric softeners. The method consists of a battery of tests,
known in the detergent industry as the KES-F system of Kawabata.
The method is described in S. Kawabata, "The Standardization and
Analysis of Hand Evaluation", 2nd Ed., Textile Mach. Soc. of
Japan, Osaka, 1980 The shear hys~eresis parametër 2HG5 of the
K~S-F system is believed to be particularly useful in the
characterization of fabric softening clays. Preferred herein are
hectorite clays which, when incorporated in fabric conditioning
,~
compositions at 10~, by weight, reduce the shear hysteresis of
fabrics laundered therein by at least 32%, more preferable by at
least 35%. The shear hysteres;s parameter 2HG~ is discussed in
more detail in Finnimore and Koenig, Melliand Textilberichte 67
(1986) pages 514-516.
Softness measurements can also be obtained from expert
panelists' subjective assessment of softness relative to a
control.
~he preferred hectorite clays used in the fabric conditioning
compositions can be further characterized by their high level of
deposition onto fabrics. Deposition of hectorite clays of the
present invention from fabric conditioning composition onto
fabrics is surpr;singly greater than the deposition of other
IS naturally occurring clays. Deposition can be measured accordin~
to the Relative Deposition procedure described on pages 13-16.
The Relative Oeposition of the clays of the present invention for
77 ppm treatment levels is preferably at least about 2.5 more
preferably at least about 2.7, and most preferably at least about
2.9 as defined therein. As used herein, ~Relative Deposition"
shall refer to the above-referenced procedure using a 77 ppm
treatment level, unless otherwise specifically indicated.The
deposition of these clays appears to be proportional to the
softness of the treated fabric. Examples of suitable hectorite
clays include Bentone~ EW and Macaloid~ both mined in or near
Amargosa Valley, Nevada (U.S.A.) and available from NL Chemicals,
NJ. Naturally occurring hectorite clays within the scope of the
present invention also include IMV Hectorite~ available from
Industrial Mineral Ventures, Amargosa Valley, Nevada. Also
encompassed herein are hectorites mined in ~urkey such as, but not
limited to, Turkish calcium hectorite clay.
~''
- 10 -
Additional Conditioning Ingredients
The fabric conditioning compositions of the present invention
~ay further contain, in addition to the clay material, other
fabric conditioning ingredients. Organic and inorganic materials
can be included either as part of the hectorite-conta;ning
agglomerates, or as separate particles or agglomerates admixed
with the hectorite-containing agglomerates. Suitable examples
include amines of the formula R~R2R3N, wherein R1 is C~ to C20
hydrocarbyl, R2 is C1 to C2~ hydrocarbyl, and R3 is C1 to C10
hydrocarbyl or hydrogen. A preferred amine of this type is
ditallowmethylamine.
Preferably, the conditioning amine is present as a complex
with a fatty acid of the formula RCOOH, wherein R is a Cg to C20
alkyl or alkenyl. It is desirable that the amine/fatty acid
complex be present in the form of microfine particles, having a
particle size in the range of from e.g., 0.1 to 20 micrometers.
These amine/fatty acid complexes are disclosed more fully in
published European Pa~ent Ap~lication No. 0 133 80~.
Preferred are compositions that contain from l% to
10% of the amine
Suitable are also complexes of the above described amine and
phosphate esters of the formula
O O
Ra P OH and HO P ~ OH
OR9 OR9
wherein R9 and R3 are C1-C20 alkyl, or ethoxylated alkyl groups of
the general formula alkyl-~OCH~CH2)y, wherein the alkyl
substituent is C1-C20~ preferably C0-C16, and y is an integer
to 15, preferably 2-10, most preferably 2-5. Am;ne/phosD~at.e
ester complexes of this type are more fully disclosed inpublished
European Patent Application No~ 0 168 889.
Further examples of optional conditioning ingredients include the amides
of the formllla R1oRIlNCORl2~ wherein R1o and R11 are independently selected
from Cl-C22 alkyl, alkenyl, hydroxyl alkyl, aryl, and alkyl-aryl groups; Rl2 is
hydrogen, or a Cl-C22 alkyl or alkenyl, an aryl or alkyl-aryl group. Preferred
examples of these amides are ditallow acetamide and ditallow benzamide.
Good results are obtained when the amides are present in the composition in
the form of a composite with a fatty acid or with a phosphate ester, as
described hereinbefore for the softening amines.
The amides are present in the composition at 1%-10% by weight.
The additional conditioning ingredients may be incorporated into the
conditioning compositions by those methods known in the art. Thus the
adclitional softness can be addecl to the crutcher mix and spray-clried, or may
be added as a dry powcler to a clay slurry which is then IEormecl into the
agglomerates of the present invention, or may be sprayed onto the clay
agglomerates or onto a carrier, either in melted or in dissolved form. An
example of a suitable carrier is perborate monohydrate.
Suitable conditioning ingredients are also the amines disclosed in
C~n~1iz)n Patent 1286059, pub]ished July 16, 1991, in particular the substitutedcyclic amines disclosed therein. Suitable are imidazolines of the general
formula 1-(higher alkyl) amido (lower alkyl)-2-(higher alkyl) ;midazoline
wherein higher alkyl is alkyl having *om 12 to 22 carbon atoms, and lower
alkyl is alkyl having from 1 to 4 carbon atoms. Softener materials of this type
are preferably added to the composition as particles or agglomerates as
disclosed in U.S. Patent 4,770,815, issued September 13, 1988 by Baker et al.
.,;
- l2 -
A preferred cyclic amine is l-tallowamidoethyl-2-tallow
imidazoline. Preferred compositions contain from 1% to lO~O of the
substituted cyclic amine.
It may also be desirable to include a conditioning agent
which controls static in the dryer. Suitable static control
agents include ion-pair complexes of the formula (R~R2R3N+H) ~A-)
~her~in RI and R2 are C,2-C20 alkyl or alkenyl, R3 is H or CH3 and
A- is an anion, such as a Cl-C~3 linear alkyl benzene sulfonate.
These and other suitable anti-static agents are disclosed in U.S. Patent
3,959,155, R.E. Montgomery, et al., issued May 25, 1976.
Moreover, the compositions herein can contain, in addition to
ingredients already mentioned, various other optional ingredients
typically used in commercial products to provide aesthetic or
additional product performance benefits. Typ;cal ingredients
include pH regulants, perfumes, dyes, bleach, optical brighteners,
soil suspending agents, hydrotropes and gel-control agents,
freeze-thaw stabilizers, bactericides, preservatives, carriers for
such optional ingredients, and the like.
The fabric conditioning compositions are typical1y used at a
concentration to provide in the rinse cycle at least about 75 ppm,
preferably at least about 100 ppm, and less than about 200 ppm,
more preferably between about 100 ppm and about 150 ppm, of clay
based upon the clay/water weight ratio. When used at
concentration of 150 ppm, the compositions encompassed by the
present invention will typically have a Relative Depos;tion, as
measured by the test described in the Experimental, of at least
about }3.0 in an aqueous laundry bath at pH 7-ll. The fabric
conditioning can be carried out oYer the range from about 5'C to
the boil.
-
~...... . ~ , j
- 13 -
EXPER~MENTAL
Relative Deposition Measurement
A. ~ashing procedure:
Prewash: Cotton/Polyester (86Yo/14~) terry cloths (Style 4025,
Dundee Mills, Griffin, GA) that are 11 X 11 square inches ~27.9 X
27.9 square cm) and weigh about 509 each a~e used for the Relative
Deposition test. The cloths are washed two times with
conventional non-clay containing detergent formulation (shown
below) in 0 grain/gallon water at 125~F (52~C) for 12 minutes
each, then washed two times in 0 grain/gallon water at 125~F
(52~C) without detergent and dried in a Whirlpool 3 Cycle Portable
Dryer tModel ~LE4905XM, Whirlpool Corp., Benton Harbor, MI).
Prewash Deterqent Composition:
Ingredient %(Wt.)
C12 Linear Alkyl Benzene Sulfonate (Na Salt) 4.1
Tallow Alcohol Sulfate (Na Salt) 5.0
NeodolR 23-6.S (Alkyl Ethoxylate) 2.0
Tallow Soap 1.9
Sodium Tripolyphosphate 32.0
Silicate 6.5
~ater and Miscellaneous --balance to 100--
Test Wash: A miniwasher with five pots (such as those
manufactured by Yorktown Tool & Die Corp., Yorktown, IN) is used.
For wash added clay softener tests, 9.129 of detergent product
(Testwash Detergent Composition, as shown below) and 0.589 of a
clay of the present invention (77ppm in the wash) are added to two
gallons of 6 grain/gallon water at 95~F (35~C3 in each mini-washer
pot and agitated for two minutes. Alternately, where specifically
set forth herein~ higher clay concentrations, eg. 150 ppm, can be
* Trademark
',' ''''
utilized. This, of course, will affect results and direct
comparisons between clay concentrations are not reliable. A load
of fabrics weighing about 3419 and including test fabrics of four
of the prewashed terry cloths, six polyester/cotton (65~o/35%) 11 x
1 square inch (27.9 x 27.9 square cm) swatches (product #7435,
Test Fabrics, ~iddlesex, NJ) weighing a total of about 379, three
11 X 11 inch nylon swatches (product ~322, Test Fabrics) weighing
a total of about 189, three 11 X 11 inch polyester swatches
~product ~720-H, Test Fabrics) weighing a total of about 449, and
one polyacrylic sock (Burlington Socks, Balfour Inc.t Asheboro~
NC) weighing about 429 are added to the wash water. The fabrics
are washed for 12 min. and spin dried for two minutes. The
fabrics are then rinsed with two gallons of 6 grain/gallon water
at 70~F (2ioC) for two minutes, spin dried for two minutes, and
dried in a Whirlpool 3 Cycle Portable Dryer(~od~i ~No.LE~905XM,
Whirlpool Corp., Benton Harbor, MI). This test wash procedure ls
repeated for a second cycle, and the Relative Deposition is
measured as described belo~.
Test ~ash Deterqent Composition
Ingredient % (~t.)
C13 Linear Alkyl Benzene Sulfonate 9.0
C14 15 Alkyl Sulfate Y.0
NeodolR 23-6.5T (Alkyl ethoxylate) 1.5
(Mfg. by Shell Chem. Co.)
Sodium Tripolyphosphate 38.4
Silicate 14.6
Sodium Carbonate 21.3
Water and Miscellaneous-~balance to 100--
B. Relative Deposition Measurement
~,~
The deposition of the clay containing compositions is calculated
based on the deposition of silicon (Si) of terry cloth swatches
washed with the test wash detergent composition relative to terry
cloth swatches that were prewashed but not subjected to the test
wash procedure (blank swatches). Silicon deposition is determined
by measurement of the X-ray fluorescence of the silicon. Each
Silicon fluorescence is measured in the following manner:
An EDAX 9500 X-ray f1uorescence unit with a rhodium anode X-ray
~ source (Philips Electronics, Inc., Cincinnati, OH3 is used. Each
terry cloth swatch is analy2ed for lO0 live seconds. Count rate
of Si (on a per second basis) for each sample is measured and
recorded.
Relative Deposition of clay is calculated by the following
equation:
Relative Deposition ~ STf - SBF X 1000
SW
wherein, STF is the Si count rate of clay-treated terry cloth
fabric~s~F is the Si count rate of blank terry cloth fabric and
SW is the Si count rate of a clay sample wafer (pressed clay
particles of same area of terry cloth fabric). Count rates of Si
for the clay sample wafer and clay deposition on fabric are
measured as follows:
(a) Si count rate for clay sample wafer: The X-ray generator is
set at 20 kV/500 microamps. About 29 of clay powder is pressed at
about 20,00Q psi into a pellet with a 30 ton hydraul;c press
(Angstrom, Inc., Chicago, IL). The sample is rotated during the
count rate analysis in a vacuum atmosphere (less than 300
millitorr).
(b) Si count rate for the terry cloth treated with clay: The
X-ray generator parameter is set at 15kV/500 microamps. A disk
with a 3cm diameter is cut from a terry cloth swatch. The disk is
compressed at about 20,Q00 psi to form a flat smooth disk using a
. ~
2~ L~~~5
- - I6 -
ton hydraulic press, then rotated during the count rate
analysis in a vacuum atmosphere.
EXAMPLES
The following product formulations exemplify the present
invention.
Example #
Ingredient (all wt. percentages) I II III IY Y
Bentone EW (NL Industries) 90% 67% 90~0 76.5% 76.S%
Sodium Carbonate 10% 33% - - 15.0%
Sodium Sulfate - - IO~o 15.0%
Silica/dye composite - - 8.5% 8.5%
In the formulations above the Bentone E~ can be replaced, in
whole or part, with ~acoloid (NL Industries), IMV Hectorite
(Industrial Mineral Ventures), or Turkish Calcium Hectorite Clay,
while still providing excellent results.
The compositions can be prepared by agglomerating the clay in
a commercial food processor, or other agglomeration equipment
known in the art, with a solution of the salt dissolved in
deionized water (eg. 15.0 9 salt per 30.0 ml water). The salt
solution should be slowly added during the agglomeration
procedure. The resulting product can be air-dried at ambient
temperature.
Optionally, a water-soluble dye can be incorporated into the
com~osition. This can be done, às in Example IV and Y, by
stirring a carrier, such as formed silica gel particles (eg.
Syloid R 234), with the agglomeration equipment and slowly adding
a dye solution (eg. 1.0 gram of F.D. & C Blue ~1 per 30 ml of
deionized water), at a final dye to silica ~eight ratio of about
1.0%, until the desired dye level (relative to the total weight of
the composition) is obtained. The silica/dye particles can then
be agglomerated, preferably with an aqueous salt solution ~15.0 9
Na2SO~ in 30.0 ml deionized water~, air dried, and admixed with
the clay particles.
- 17 -
The agglomerated clay and silica/dye particles are screened
with testing sieves known in the art to, separate agglomerates
less than 100 microns and greater than 1250 microns.
