Note: Descriptions are shown in the official language in which they were submitted.
M t147~
MEE-FLOWING POWDfR FABRIC SO~J NI~IG COMPOSlTiON
AND PROCESS FOR JTS MANLIFACTVRE
This invention relates to a free-flowing, spray-dried concentrated
particulate fabric softening composition which is readi/y dispersible in water and
to a process for its manufacture and use. More particularly, the present
invenrion relates to an effective fabric softening composition in a form which is
convenient for use, capable of containing a re/atively high proportion of cationic
fabric softener, and can be economically packaged and shipped.
Fabric softening or conditioning compositions for use in househo/d
washing machines are marketed extensive/y in the United States and Europe.
Genera//y, these compositions are aqueous /;quids containing as the principal
active ingredient a cationic quaternary ammonium compound to impart a
softening effect to fabrics treated therewith in the laundry bath Typica/iy,
these fabric softeners ~the common designation for such softening
compositionsJ contain from about 5 to 8% of the active catianic softening
compound. In a Unlted States washing machine containing about 6~ /iters of
water, norma/ly about 90 grams of a 6% active liquid fabric softener is added to
the rinse cycle to achieve an acceptable softening leve/
Liqufd fabric softeners, however, have certain inherent disadvantages
The level of the active cationic ~uaternary ammon~um compound capahJe of
2~8~18
being introduced into an aqueous system is generally limited by properties of
solubiljty of ~he qvaternary compovnd and stability and pourabliity of the f;nal
product. Conventional rinse-added fabric softening compositions contain
quaternary ammonium compounds, typica//y having two /ong alky/ chains,
which are substantia/ly water-insoluble materials. The softening compositions
are, therefore, normally in the form of an aqveous dispersion or emulsion.
Conseqvently, at higher concentrations of the active cationic softening
compound, genera/Jy above about 6%, by weight, prob/ems in product
formu/ation, stabi/ity ~i.e. product separationJ, gel-formation and water
dispersibi/ity are /ikely to occvr. At concentrations above about 9%, by weight,
of quaternary ammonium compounds, the viscosity and stability of the aqueous
liquid softener are often unacceptable for commercial purposes.
There are also economic disadvantages associated with marketing /iqvid
fabric softeners. These primari/y re/ate to the substan~ia/ costs of pacJ~aging
and shipping bott/es of a di/ute aqveovs /iqvid prodvct containing a re/atively
/ow leve/ of active softening ingredient. The pac/~aging also poses a prob/em
from an environmental standpoint. The manvfacture and disposal of p/as~ic
containers, which are common/y vsed for liqvid hovsehold products are often
incompatible with consumer demands in the United States and Evrope for the
vse of recyc/able pac/~aging materia/s which are readi/y biodegradabJe.
According/y, there is a need in ttJe art for a fabric softenjng composit;on in
particu/ate form capable of containing re/atively high concentrations of active
softenjrtg ingredients and capabJe of being supplied in an economica//y pac/~aged
form.
Fabric softeners in powdered form are described in the patent literatrJre.
/n U.S. Patent 2,940 816 there is described a powdered fabric softener
comprised of a defined quaternary ammonium compound in combination with
urea. U.S. Patent 3,256,180 describes a process for producing a fabric
softener which comprises reacting urea with a quaternary ammonium compound
in the presence of water to form a granular product. U.S. Patent Nos.
3,356,526 and 3,573,091 to Woldman et. al. relate to a process for preparing
a powdered quaternary softener wherein a solution of the quaternary ammonium
compound is sprayed onto a particulate carrier, such as urea or sodium
tripolyphosphate, so as to provide particles of carrier having a coating of the
softener.
U.S. Patent 4,427,558 to David discloses fabric softening particles
comprised of a quaternary ammonium compound, urea, and a calcium soap
such as calcium tallow soap. The process of preparation comprises forming a
liquid mixture of the desired components, cooling the liquid to form a solid and
then grinding to form particles. Prior to grinding, the solid is "weathered" for
severa/ hours, the term "weathering " being used to describe the process of
alJowing the water content of the particles to approach equilibrium with rhe
environment. Particles may also be formed, according to the disclosure, by
"spray coo/ing " a Jiquid mixture whereby a solid is formed with no
accompanying loss of water. ~he resulting solid is then ground and weathered.
In European Patent App/ication EP 1315 tProcter & Gamb/e) there is
described a process whereby mo/ten partic/es of a quaternary ammonjum
compound and a dispersion inhibitor such as a fatty alcohol or fatty acid are
~ttached to spray-drjed base detergent granu/es containing surfactant and
builder The emphasis in this as well as other patents in the /iterature is to
avoid dispersing the cationic softening compound in the wash water in order to
prevent its inactivation in the wash solution, In those patents which seek to
provide a quaternary ammonium compound in the form of a readily dispersib/e
powder in cold water, with particular emphasis on rinse-cyc/e app/ications, such
dispersibility has remained a problem, particularly at higher concentrations of
the quaternary compounds.
It has now been discovered that a highly concentrated particulate fabric
softening composition can be prepared in accordance with the invention by a
spray drying process which provides partic/es of a softening composition
containing up to about 40% of a cationic softening compound in combination
with a nonionic and/or an anionic surfactant, among other components, which
particles are readi/y dispersible jn water and provide effective softening.
SUMMARY OF T~JE INVENTION
According/y, the present invention provides a free-flowing spr~y-dried
particu/ate fabric softening composition which is readily dispersible in water
comprising:
laJ from about 5 to 40%, by weight, of a cationic quaternary
ammonium softening compound;
IbJ from about 0.5 to 15%, by weight, of an anionic and/ora nonionic
detergen~ compound; and
IcJ from about 45 to 85%, by weight, of urea; the balance being
water.
/n a preferred embod~ment of the invention the composition further
contains from about 1 to 10%, by weight, of a fatty acid alkano/amide.
The invention a/so encompasses a process of producing a free-flowing
spray-dried particuiate fabric softening composition whjch is readi/y dispersible
in water comprising:
~aJ forming a crutcher slurry containing:
~iJ from about 5 to 40%, by weight, of a cationic quaternary
ammonium softening compound;
~ii/ from about 0. 5 to 15%, by weight, of an anionic and/or a
nonionic detergent compound;
~iii) from about I to 10%, by weight, or an a/kanolamide; and
tivJ from about 45 to 85%, by weight, of urea, the ~bove
percentages being based on the so/ids content of the slurry,
in the absence of w3ter;
~bJ mixing the crutcher sJurry formed in step ~aJ such that a uniform
mixture or dispersion is formed having an aver7ge particle size of
less than about 1. 0 micron and there~fter;
~cJ spray drying the aforesaid mixture or dispersion in a spray tower
wherein the water content of the mixture is substantially
evaporated to provide free-flowing particles of a softening
composition capable of being readily dispersed jn water
The invention is predicated on the discovery that a fabric softening
composition can be prepared in particulate form by spr~y drying to provide a
composition more highly concentr~ted than conventiona/ liquid rinse-cycle
2 ~
;ofteners. ~e resulting spr~y dried partic~es are dis,oersJ'~le in water and
provjde effective softening to fabrics in a wash or r~'nse cycle aqueous bath. An
essential feature of the composition of the invention is that uniform spray dried
particles are formed by utilizing a mixjng step prior to spray drying the crutcher
slurry such that the contents of the crutcher slurry are thoroughly dispersed and
form a mixture or dispersion having an average particle size of below about 1. 0
micron, Uniform mixtures of this type may be achieved with various types of
mixers, miJls or pumps known in the art, but it is preferred to use a so-called
"homogenizer" such as a Gaulin Homogenizer marketed by Gaulin Corporation
of Everett, Massachusetts, U. S.A. or Hilversum, Ho/land, which consists
essential/y of a positive disp/acement pump to which is attached a
homogenizing va/ve assembly capab/e of providing an intimate mixture having
an average partic/e size diameter of be/ow about 1. 0 microns, and more
preferably be/ow about 0. 7~; microns. The preferreg maximum size of partic/es
in such mixture is be/ow about 5.0 microns and more preferably be/ow about
3. 0 microns.
DETAJLEf:) DESCfi~/PTlON Of J/JE JNVEN~/ON
The process of spray drying a softening composition in accordance with
the invention uti/izes, for the most part, we// known technology reJating to the
productjon of particu/ate detergent compositions. General/y, an a~ueovs
crutcher slurry is formed containing a mixture of water with many or most of
the ingredients desired in the fabric softening composition ~he soJids content
of the s/urry is genera~/y from aoout 20% to about 70%, preferabJy 30% to
60%, and most preferab/y from 40% to 50~0 thereof, ~he ba/ance being water.
The crutcher s/urry is then atomjzed by pumping it an atomizing nozzle at a
pressure of about 1000 to 2000 psi in~o a spray-drying tower, the typical
dimensions of a commercial tower being about 35-100 feet in height and about
12-30 feet in diameter At the base of the tower, air is introduced at a
temperature of from about 300-1000F which contacts the atomized s/urry to
provide a hot drying gas for the drop/ets of the slurry thereby evaporating most
of the water. Jhe resulting partic/es or beads are co//ected at the bottom of the
tower, the moisture and heated air existjng at the top. Heat or water-sensjtive
ngredients such as perfume may be post-added to the tower particles jn a
subsequent mixjng or blending operation
The crutcher slurry is preferably made by sequentjally adding the various
components thereof in the manner which will result in the most miscjble and
readily pumpable slurry for spray drying. Jhe order of addition of the various
components may be varied, depending on the circumstances. Norma/ly, it is
preferab/e for a// or a/most all of the water to be added to the crutcher first,
preferably at about the processing temperature, after which the other
components are added in sequence namely, urea, the quaternary ammonium
sof~ening compound, anionic and/or nonionic surfactants, a fatty acid
alkanolamides and optionally adjuvants, such as pigments, anti-oxidants and
germicides.
The temperature of the aqueous medium in the crutcher wil/ usually be
about room temperature or elevated, normally being in the 20 to 70C range,
and preferably from about 25 to 40C.
62301~
Crutcher mixing times to obtain thoroughly mixed homogeneous s/urrles
can Yary wide/y, from as littte as five minutes in sma/l crutchers and for slurr/es
of higher moisture contents, to as much as one hovr, in some cases, although
30 minutes is a preferable upper /imit. Following mixing in the crutcher, the
crutcher s/urry is transferred for further mixing to a "homogemzer" or s~milar
mixer or pump to obtain the uniform dispersion or mixture described above
having an average particle size of below about 1.0 micron.
Jhe resulting dispersion is thereafter transferred in the usual manner to a
spray drying tower, which is located near the crutcher. Jhe dispersion is forced
at high pressure through spray nozzles into the spray tower ~countercurrent or
concurrentJ, wherein the drop/ets of the s/urry fa/l through a hot drying gas to
form particles or beads of the fabric softening composition while evaporating
substantially all the water The moisture content of the particles is preferably
about 2 to 4%, by weight.
The cationic ~uaternary ammonium softening compounds useful for the
invention include imidazolinium salts, di-long chain a/kyl quaternary ammonium
sa/ts and diesterified long chain fatty acid di/ower alkyl ~uaternary ammonium
salts. The general structure of the preferred imidazolinium salts is shown
below
r f l 1
N N R3 !
~f~ \~ j X
R
f~ ~
wherein:
P~ is a C8 to C30 a/iphatic radical and preferably a C,4 to C"~ alkyl or
alkenyl;
R2 and R3 independently may be any of R, or preferably, /ower a/kyl or
substituted alkyl of (~, to C4 such as haloaJkyl, hydroxya/kyl, acylaminoalkyl and
the like;
X is a water-so/ubiljzing anion such as chloride, bromide, iodide, fluoride,
sulfate, methosulfate, nitrite, nitrate, phosphate and carboxylate, le.g. acetate,
adipate, phtha/ate, benzoate, o/eate, etc.);
Typical imidazo/inium softening compounds inc~ude:
2-heptadecy/- 1-methy/- 1-o/ey/amidoethy/ imidazo/inium ethosu/fate
2-heptadecyl- 1-methyl- J - /2-stearoylamidoJethyl - imidazolinium sulfate,
2-heptadecyl- 1-methyl- 1- /2-stearoylamidoJethyl - imidazolinium chloride,
2-coco- 1-12-hydroxyethyl~- 1-benzyl imidazolinium chloride,
2-coco- 1-~hydroxyethylJ- 1-(4-ch/orobutylJ imidazolinium chloride,
2-coco- 1-~2-hydroxyethyl)- 1-octadecenyl imidazolinium chloride,
2-tall oil fatty- 1-12-hydroxyethyl)- 1-benzyl imidazolinium ch/oride,
2-tal/ oil fatty- 1-~2 hydroxyethylJ- 1-~4-chtorobutylJ-imidazolinium chloride,
2-h~ptadecenyl- 1-12-hydroxyethyl)- 1-14-chlorobutylJ-imidazolinium
chloride,
2-heptadecenyl- 1-12-hydroxyethyl) 1-benzyl imidazolinium chloride.
2-heptadecyl- 1-~hydroxyethylJ- 1-octadecylimjdazolinium ethyl sulfste.
The genera/ structure of the di-/ong chsin all~yl quaternary ammonium
salts js shown below:
12J I /~ +
R N ! Y~
R
wherein the R groups are selected from C, to C30 aliphatic, preferably alkyl or
alkenyl; aryl ~e,g. phenyl, toloyl, cumyl, etc.J; aralkyl ~e.g. benzyl, phenethyl,
methylbenzyl, etc.J; and the halo, amide, hydroxyl, and carhoxy sustituents
thereof such as halo C2 to C6 alkyl /e.g. 2-chloroethyl~; and hydroxy C2 to C6
alkyl ~e.g. 2-hydroxyethylJ; with the proviso that at least two R's are C~2 to C30
and preferably C~2 ~0 C22 and the others are lower alkyl; more preferably at least
two R's are C~2 to C,O and the others are /ower alkyl of C, to C4 ~and most
preferably methy/ or ethyll and Y is an anion as defined for X jn Formula ~1J.
Typical quaternary ammonium salts of formula ~2J include the following:
distearyl dimethyl ammonium chloride
djtallow dimethyl ammonium chloride
dihexadecyl dimethyl ammonium chloride
dis~eary/ dimethyl ammonium bromide
di~hydrogenated ta/low~ dimethyl ammonium bromide
dJstearyl, dilisopropylJ ammonium chloride
djstearyl dimethyl ammonium methosulfate.
di (hydro~qenated tallow~ dimethyl ammonium methosu/fate.
Another preferred class of the carjomc fabric softeners are diesterifjed
long chajn fatty acid di/ower alkyl quaternary ammonium salts and diesterified
c~
long cha~n fatty acid Jower alky1 Jower hydroxy alkyl quate~nary ammonium
salts. This class of cationic fabric softeners can be represented by the generalformula:
1~ +
R40CA
O
R3_ IV_ R40CR~ X
wherein RC0 represents the residue of a f~tty acid having from about 12 to 24
carbon atoms;
R2 and R3 represent independent/y a /ower a/ky/ group or a hydroxyall~yl
group having 1 to 4 carbon atoms, and preferably 1 to 3 carbon atoms;
R4 represents a /ower aJky/ene group having 1 to 4 carbon atoms,
preferably 1 to 3, and most preferably has 2 carbon atoms, i. e. R4 is
-- CH2CH2 --; and X is a water-so/ubi/izing anion as defined above Such
compounds are commercially avallable from, for instance, Stepan Chemica/ Co.
under the Stepantex trademar*, such as Stepantex VHR90 which has the
formula:
ICH2CH200CR
CH3 V--CH2CH200CR.X
CH2CH20H
where RC0 is derived from tallow or coco fatty acids and X may be chJoride or
su/fate.
The quaternary ammonium softening compound is generaJly from a~out 5
to 40%, by weight, of the partjculate softening composition, preferably from
about 10 to 30%, and most preferably from about 15 ~o 25%, by weight.
An optional fabric softening ingredient is a fatty a/cohol wherein the
hydrophobic group may be a straight or branched chain alky/ or alkenyl group
having from about 10 to 24, preferably from abovt 10 to 20, especially
preferably from about 12 to 20 carbon atoms. Specific examples of the fatty
alcohol inc/ude decanol, dodecano/, tetradecanol, pentadecanol, hexadecanol,
octadecano/, l~uryl alcohol, palmityl alcohol, stearyl alcohol, oleyl alcohol, and
mixtvres thereof. Furthermore, the fatty alcohol may be of natural or synthetic
origin and may include, for example, mixed a/cohol, such as C,6 to C,0 alcoho/s
prepared by Zjegler polymerization of ethylene,
The fatty alcohol may be present in the composition in a minor amount
relative to the cationic fabric softener such ~hat the ratio, by weight, of the
cationic fabric softener to fatty alcohol is in the range of from abovt 6:1 to 2:1,
especial/y preferably about ~:1 to 3:1.
The fatty acid aJkano/amides useful in the present invention are those
derived from fatty acid amides whose alkyl radical contains at least 12 carbon
atoms. They preferably have the general formula:
R If_ N
O Cnfl2nOh'
wherein n is 2 or 3. A preferred material is coco monoethanolamide.
12
2~ 8
~ he concentration of fatty acid alkanolamide in the sof~ening composi~ion
is genera//y from aoout 1 to 10%, ~y weight, and preferably from abovt 1 to
5%, by weight. The combination of fatty acid alkanolamide and quaternary
ammonium softening compound in accordance with the invention provides a
superior softening effect to fabrics.
An essential component of the fabric softening composition is urea. The
particles general/y contain from about 45 to 85/6, by weight, of urea, preferably
from about 55 to 7~%, and most preferably from ahout 60 to 70%, by weight.
Another important ingredient for purposes of improving particle solubility
and dispersibility is an anionic and/or nonionic svrfactant. Among the
anionic surface active agents useful in the present invention are those surface
active compounds which contain an organic hydrophobic group contajning from
about 8 to 26 carbon atoms and preferably from about 10 to 18 carbon atoms
in their molecular structure and at /east one water-solubilizing group selected
from the group of sulfonate, sulfate, carboxylate, phosphorate and phosphate
so as to form a water-soluble detergent.
Examples of suitable anionic detergents include soaps, such as, the
water-solubJe salts le.g., the sodium potassjum, ammonium and aJ~anol-
ammonium salts~ of hlgher fatty acids or resin salts cont~ining from about 8 to
20 carbon atoms and preferably 10 to 18 carbon atoms Particularly useful are
the sodium and potassium salts of the fatty acid mixtures derived fr~m coconut
oil and tallow, for example, sodium coconut soap and pot~ssium tallow soap.
The anionic c~ass of detergents also includes the water-soluble sulfated
and sulfonated detergents having an aliphatic, preferably an aJkyl radical
containjng from a~out 8 to 26, and preferab/y from abovt J2 ro 2~ carbon
atoms. Examples of the suffonated anionic detergents are the higher alky/
aromatic sulfonates such as the higher alkyl benzene sulfonates containing from
about 10 to 16 carbon atoms in the higher alkyl group in a straight or branched
chain, such as, for examp/e, the sodium, potassiurn and ammonium salts of
higher aJkyl benzene sulfonates, higher alkyl toluene sulfonates and higher alkyl
phenol sulfonates,
Other suitable anionic detergents are the olefin sulfonates including long
chain alkene sulfonates, long chain hydroxyalkane sulfonates or mixtures of
alkene sulfonates and hydroxyalkane sulfonates and hydroxyalkane sulfonates.
Other suitable anionic detergents are su/fated ethoxylated higher fatty
alcohols of the formula RO~C~t40J,r,SO3M, wherein R is a fatty alkyl of from 10
to 18 carbon atoms, m is from 2 to 6 ~preferably having a value from about 1/5
to 1/2 the number of carbon atoms in RJ and M is a solubilizing salt-forming
cation, such as an alkali me~a/, ammonium, /ower a/kylamino or lower
alkanolamino, or a higher alkyl benzene sulfonate wherein the higher alkyl is of
10 to 15 carbon atoms. The propor~ion of ethylene oxide in the
polyethoxylated higher alkanol su/fate is preferably 2 to 5 moles of ethylene
oxide groups per moJe of anionic detergent, with three moles being most
preferred, especia/ly when the higher alkanol is of 11 to 15 carbon atoms. A
preferred polyethoxylated aJcohoJ sulfate detergent is marketed by SheJJ
ChemicaJ Company as Neodol 25-3S.
The most highly preferred water-soluble anionic detergent compounds are
the ammonium and substituted ammonium ~such as mono, di and tri-
3~ ~ethanolamineJ, al~:aii metal ~such as, sodium and potassiumJ and alka/ine earth
meta/ fsuch as, ca/cium and magnesium~ sa/~s of the higher alky/ benzene
su/fonares, o/efine su/fonates and higher a/ky/ su/fates. Among the above-listed
anionics, the most preferred are the sodium linear a/kyl benzene svlfonates
/La~S), and especia//y those wnerein the a/ky/group is a straight chain a/ky/
radica/ of 12 or 13 carbon atoms.
Among the suitab/e nonionic surfactants are ~he ethoxy/ated fatty
a/coho/s having from 12 to 20 carbon atoms, and an average degrees of
ethoxy/ation of 3 to 9. Preferred nonionic detergents are coconut a/coho/s
having an average of 6 or 7 ethyoxy groups per mo/ecu/e and C,4-C,6 primari/y
a/coho/s with 6 or 7 ethoxy groups per mo/e of higher fatty a/coho/.
Ethoxy/ated /aury/ a/coho/ having about 7 mo/es of ethoxy/ate per mo/e of
a/coho/ is particularly preferred for use herejn.
Other usefu/ nonionic detergent compounds inc/ude the a/ky/po/yg/ycosjde
and a/kylpo/ysaccharide surfactants which are weJ/ known in the art.
Jhe amount of anionic surfactant in the particulate composition may vary
from O to 3%, and preferably will vary with the percentage of cationic softening
compound as fol/ows: from about 1 to 4% of anionic surfactant when the
percentage of c~tionic compound is be/ow about 20%, and from about 3 to 3%
of anionic svrfactant when the percentage of cationic softening compound is
from about 20 to 40%, a/J percentages being by weight of the particuJate
composition. Genera/ly, the leve/ of anion;c surfactant is from about 2 to 4 %,
by weight. The nonionjc surfactant is optiona//y present from about 0.5 to 5%,
by weight, and preferab/y no more than about J %, by weight.
~8~t~
The fabric softening compositions of the invention may further jnclude
additional or supp/emental ingredients whjch do not adversely affect the sta~ility
or functiona/ characteristics of the softening composition. Included among such
supplemental ingredients are perfumes, dyes, pigments, germicjdes, soi/-release
agents, f~bric crisping agents, anti-oxidants and anti-corrosion agents.
2 ~
EXAMPLE J
A granular fabric softening composition of the invention had the fo/lowing
composition:
ComDonent Weiqht Percent
DSDMAC' 24
Nonionic SurfactantZ 2
Sodium Dodecy/ Benzene Sulfonate 3
Cocomonoethanol Amide 3
Urea 64
Moisture Balance
_
'D;steary/ dimethyl ammonium chloride
2Ethoxylated lauryl alcohol having about 7
moles of ethoxylate per mo/e of alcohol.
Ten and one-half r10,5J grams of the above-described softening
composition was added to a top-loaded washing machine in the rinse cyc/e at a
water temperature of 25C and at water hardness of 100 and 320 ppm. The
dispersibjlity tjme ~f the granular product jn the water was about 1.5 minutes,
The softness and hydrophilicity of the resulting fabrics was measured and
compared with the measured softness for fabrics conditioned in the same top
loading machine with forty two ~42J grams of a commercial liquid fabric
softener containing 6% of a quaternary ammonium softener. The fabrics
conditioned with the granular softening composition of the invention were
measurably softer and equal in hydrophilic properties to those conditioned with
the commercial liquid product.
?7
