Fabric softener composition

A fabric softener composition with improved fabric softening performance is based upon a mixture of quaternary ammonium fatty acid derivatives one of which is obtained from partially hydrogenated soy triglyceride or fatty acids derived from such triglyceride possessing certain properties of cis/trans isomer ratio and iodine value and the other of which is obtained from tallow acids.

BACKGROUND OF THE INVENTION 
This invention relates to fabric softener compositions containing 
quaternized derivatives of fatty acids. More particularly, the invention 
relates to a fabric softener composition containing at least two different 
quaternary ammonium fatty acid derivatives, one such derivative being 
based on fatty acids obtained from soy and the other being based on fatty 
acids derived from tallow. 
Fabric softeners are compositions containing one or more active substances 
which are used in the laundering process to provide laundered fabrics with 
a texture or hand that is smooth, pliable and soft to the touch. Fabric 
softeners generally contain one or more cationic surfactants in the form 
of water-insoluble quaternary ammonium compounds in which the ammonium 
nitrogen atom contains at least two long chain acyclic aliphatic 
hydrocarbon groups. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a fabric softener composition is 
provided which comprises: 
a) a first quaternary ammonium fatty acid derivative obtained by the 
process which comprises reacting partially hydrogenated soy triglyceride 
or partially hydrogenated fatty acids obtained from soy triglyceride, the 
aliphatic residues of which possess a ratio of cis isomer to trans isomer 
of from about 1:1 to about 15:1 and an iodine value of not less than about 
30 and not greater than about 70, with a secondary amine of the formula 
X'--R'--NH--R"--X" in which X' and X" each is the same or different and is 
--OH or --NH.sub.2 and R' and R" each is the same or different and is 
alkylene of from 2 to about 6 carbon atoms in a mole ratio of 
triglyceride/fatty acid to amine of at least about 1.85:1 to provide the 
corresponding aminodiester, -diamide or -esteramide, alkoxylating the 
aminodiester, -diamide or -esteramide with an alkylene oxide selected from 
the group consisting of ethylene oxide, propylene oxide and butylene oxide 
in a mole ratio of alkylene oxide to aminodiester, -diamide or -esteramide 
of up to about 8:1 to provide an alkoxylated fatty acid derivative and 
quaternizing the alkoxylated fatty acid derivative with alkylating agent 
to provide the corresponding quaternary ammonium fatty acid derivative; 
and, 
b) a second quaternary ammonium fatty acid derivative obtained from tallow 
acids. 
Surprisingly, it has been found that the foregoing fabric softener 
composition provides significantly better softening performance than a 
fabric softener composition containing an equivalent amount of quaternary 
ammonium fatty acid derivative obtained entirely from tallow acids. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The first of the quaternary ammonium fatty acid derivatives present in the 
fabric softener composition of this invention is obtained by derivatizing 
one or more fatty acids obtained from soy triglycerides. The soy 
triglyceride or free fatty acid(s) derived from soy triglyceride are first 
hydrogenated employing known and conventional procedures to provide a 
partially hydrogenated product in which the aliphatic residues possess a 
ratio of cis isomer to trans isomer of from about 1:1 to about 15:1, 
preferably from about 2:1 to about 9:1, and an iodine value of not less 
than about 30 and not greater than about 70 and preferably not less than 
about 35 and not greater than about 58. It is generally preferred to 
hydrogenate soy triglyceride; however, the free fatty acids can also be 
hydrogenated. Care is taken to reduce or remove polyunsaturates that may 
be present in the hydrogenated product in order to increase the color and 
odor stability of the quaternary ammonium derivatives ultimately obtained 
therefrom. Generally useful hydrogenation conditions for hydrogenating soy 
triglycerides include the use of from about 0.02 to about 0.15 weight 
percent of a typical hydrogenation catalyst such as Nickel supported 
catalyst e.g., G49B.RTM. from United Catalysts, Inc., Louisville, Ky., a 
filter aid such as Celite.RTM. or diatomaceous earth in the usual amount 
of from about 0.05 to about 5% of the material being filtered, hydrogen 
gas at a pressure of from 50 psi to about 600 psi, a temperature of from 
about 60.degree. to about 150.degree. C. and a reaction time of from about 
0.5 to about 4 hours. 
One example of the C-chain distribution of a soy triglyceride both before 
and following partial hydrogenation in accordance with this invention can 
be as follows: 
______________________________________ 
C.sub.16 :0 
C.sub.18 :0 
C.sub.18 :1 
C.sub.18 :2 
C.sub.18 :3 
______________________________________ 
Before Hydrogenation, % 
11 4.0 21 55.5 18.5 
Following Hydrogenation, % 
11 .about.30 
.about.60 
.about.0 
.about.0 
______________________________________ 
Other distributions can be achieved depending on the conditions of 
hydrogenation. 
Hydrogenation conditions other than those stated can be used as appreciated 
by those skilled in the art provided, of course, that the foregoing 
properties of cis to trans isomer ratio and iodine value are obtained in 
the partially hydrogenated product. 
The partially hydrogenated soy glyceride/fatty acids are then reacted with 
a secondary amine of the general formula 
EQU X'--R'--NH--R"--X" 
in which X' and X" each is the same or different and is --OH or --NH.sub.2, 
and R' and R" each is alkylene of from 2 to about 6 carbon atoms. The 
secondary amine can thus possess two hydroxyl groups, two primary amine 
groups or a hydroxyl group and a primary amine group. A preferred 
secondary amine reactant is diethylenetriamine. The glyceride/fatty acids 
are reacted with the secondary amine in a mole ratio of at least about 2:1 
based on the number of moles of free or bound fatty acids. This reaction 
provides a diester, diamide or ester amide (depending on the nature of the 
X' and X" groups) which can be represented by the following general 
formula (I): 
EQU R--CO--X'--R'--NH--R"--X"--CO--R (I) 
in which each R is the same or different and is the residue of partially 
hydrogenated soy triglyceride/fatty acids possessing the aforementioned 
ranges of cis/trans isomer ratio and maximum iodine value. 
This reaction product is preferably stabilized with an antioxidant/reducing 
agent (such as, e.g., BHT/sodium borohydride) to preserve its color and 
odor qualities. Preferably the antioxidant is a phenolic antioxidant 
including but not limited to 3,5-Di-tert-butyl-4-hydroxy toluene (BHT); 
3,5-Di-tert-butyl-4-hydroxy anisole (BHA); Corn oil-60%, butylated 
hydroxytoluene-20%, butylated hydroxyanisole-10%, propyl gallate-6%, 
citric acid-6% (Tenox.RTM.6); octadecyl 
3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox.RTM.10); and 
3,5-Di-tert-butyl-4-hydroxyhydrocinnamic acid, triester with 
1,3,5-tris(2-hydroxyethyl)-s-triazine-2,4,6(1H,3H,5H)-trione (Irganox.RTM. 
3125). IRGANOX.RTM. 1076 and IRGANOX.RTM. 3125 are trademarks of Ciba 
Geigy Corporation, while TENOX.RTM.4 and TENOX.RTM.6 are trademarks of 
Eastman Chemical Co. Other antioxidants useful herein are readily apparent 
to one of ordinary skill in the art and can be found, for example, in 
McCutchen's Functional Materials, 1995 (McPublishing Co., N.J., U.S.A.) 
the relevant portions thereof being incorporated herein by reference. 
The reaction product of the foregoing general formula (I) is also 
preferably alkoxylated with an alkylene oxide such as ethylene oxide, 
propylene oxide or butylene oxide to provide the corresponding alkoxylated 
diester, diamide or esteramide. The mole ratio of alkylene oxide to 
diester, diamide or esteramide is at least 1 to about 8 and is preferably 
from about 1 to about 4. The alkoxylated product can be represented by the 
following general formula (II): 
##STR1## 
in which x is 2 to 4 and n is 1 to about 8 and preferably 1 to 4. 
The alkoxylated product is then quaternized with any of several known and 
conventional alkylating agents, e.g., those of the formula 
EQU R'".sub.m A 
in which R'" is hydrogen, an alkyl radical of 1 to about 4 carbon atoms or 
a phenalkyl radical of 1 or 2 carbon atoms in the alkyl radical, m is the 
valence A and A is the residue of an organic or inorganic acid. Examples 
of suitable alkylating agents include the alkyhalides such as methyl 
chloride, the benzylhalides such as benzyl chloride and the 
dialkylsulfates such as dimethyl sulfate. The resulting quaternized fatty 
acid derivative can be presented by the formula 
##STR2## 
The second quaternary ammonium fatty acid derivative can be represented by 
the general formula 
##STR3## 
in which R.sup.1 and R.sup.3 each is the same or different and is the 
hydrogenated residue of fatty acid derived from tallow and is selected 
from C.sub.12 -C.sub.22 straight or branched chain alkyl or alkylene 
groups, P is 0 or 1, R.sup.2 and R.sup.4 each is alkylene of from 2 to 6 
carbon atoms, R.sup.5 is alkyl of 1 to 4 carbon atoms, R.sup.6 is alkyl of 
1 to 4 carbon atoms or (C.sub.x H.sub.2x.O).sub.n wherein x is 2 to 4 and 
n is 1 to 8, m is the valence of A and A is as defined above. 
The preferred second quaternary ammonium fatty acid derivatives are those 
in which R.sup.2 and R.sup.4 each is --CH.sub.2 CH.sub.2 -- and R.sup.5 
and R.sup.6 each is methyl. 
The fabric softener composition can contain (a) and (b) in a weight ratio 
of (a) to (b) of about 8:1 to 1:6 and preferably about 6:1 to 1:4 together 
with one or more known and conventional additives such as fragrance, 
colorant, stabilizing agent, additional surfactant(s), antioxidants, 
chelating agents, and the like, in the usual amounts. 
Components (a) and (b) and optional additives are dispersed in water to 
provide a finished fabric softener product. The amount of water can 
represent from about 40 to about 98 weight percent of the total 
composition and preferably from about 50 to about 96 weight percent of the 
total composition of the dispersed product based on the amount of combined 
components (a) and (b). Such dispersions will possess a quaternary 
activity of at least about 2 percent and preferably at least about 4 
percent.

The following examples are further illustrative of the fabric softener 
composition herein. 
EXAMPLE 1 
In this Example, three fabric softener dispersions are prepared for 
evaluation in a sensory evaluation for softening effectiveness and in 
quantitative evaluations for rewetting of treated fabric. A 1.5 liter 
resin kettle equipped with an electric motor to drive the agitator is used 
to prepare the dispersions. Pre-blends of quaternary ammonium compounds 
are made prior to their addition to the water. 
In the first pre-blend, 50.2 grams of dihydrogenated tallow dimethyl 
ammonium chloride is heated to 60.degree. C. and combined with 92.6 grams 
of hydroxypropyl di(partially hydrogenated soya) methyl amidoamine 
methylsulfates (starting triglyceride I.V.=20). The two products are mixed 
to form a homogeneous blend to be used as the quaternary pre-blend for 
preparing the softener dispersion. 
To prepare a softener dispersion using the pre-blend, 350 grams of 
deionized water (DI) is heated to 65.degree. C. and added to the resin 
kettle which is jacketed to maintain the formulating temperature between 
60.degree. and 70.degree. C. With agitation, 3.75 grams of a dispersant 
(Igepal.RTM. CO-720 from Rhone-Poulenc) is added to the water and 
solubilized. Next, 142.8 grams of the molten quaternary pre-blend is added 
to the stirring hot water with intermediate additions of calcium chloride 
to maintain a handlable viscosity at all times. After the incorporation of 
quaternary pre-blend is completed the temperature of the batch is allowed 
to fall to 40.degree. C. At that time 3.75 grams of fragrance (Bush, 
Boake, and Allan 920165) is incorporated. The pH of the dispersion is 
adjusted to 4.5-5.0 with 1N HCl and then the dispersion was colored and 
final viscosity adjusted with calcium chloride. The net weight of the 
dispersion is then adjusted to 500 grams. The formulation is allowed to 
age for approximately 1 week prior to evaluation for softening 
effectiveness. 
A second dispersion in accordance with this disclosure is prepared in a 
similar manner except that the amidoamine quaternary used is based upon a 
partially hydrogenated soya triglyceride where the triglyceride had been 
hydrogenated to an I.V. of 50 cg/gm. 
The aforementioned products were then compared with a softener dispersion 
formulated as above with the exception being that a hydroxypropyl ditallow 
methyl amidoamine methyl sulfate is used in place of the similar product 
based upon soya triglyceride. 
Garments were then treated using the three dispersions by washing seven 
pounds of fabric in a topload clothes washer and adding about one fluid 
ounce of the dispersion (24% actives) during the rinse cycle. The use 
level per treatment was approximately 7 grams of active per 7 lbs. of 
fabric. The garments were dried for 50 minutes on a high setting in a 
tumble drier and then bagged and allowed to equilibrate for 24 hrs. Next, 
pairs of towels were presented to trained panelists with the requirement 
that they judge which towel of the pair to be softer. No judgment of 
equality was permitted. The number of judges ranged from 18 to 24 for each 
test conducted. 
The results indicated that the dispersion made from soya triglyceride 
(I.V.=50) gave the best softening performance. When the I.V. of the soya 
triglyceride was 20, the performance relative to the tallow-based product 
decreased. This was surprising and an unexpected result based upon 
knowledge of those skilled in the art regarding I.V. and its influence on 
softening performance. 
In several tests the softening preference was compared for the I.V.=20 soya 
triglyceride amidoamine quaternary to that of the tallow-based quaternary 
and the softening preference for the I.V.=50 soya triglyceride amitoamine 
quaternary was compared to that of the tallow-based quaterary. The results 
can be summarized as follows: 
______________________________________ 
AAQ (Tallow based) 
AAQ (I.V. = 20 soya triglyceride) 
______________________________________ 
Test 1 67% 33% 
Test 2 72% 28% 
Test 3 71% 29% 
______________________________________ 
AAQ (Tallow based) 
AAQ (I.V. = 50 soya triglyceride) 
______________________________________ 
Test 4 29% 71% 
Test 5 40% 60% 
Test 6 35% 65% 
______________________________________ 
EXAMPLE 2 
In a second example three softener dispersions were prepared in the same 
manner as in Example 1. The alkyl chain source of the amidoamine 
quaternary used to form the first dispersion was a soya triglyceride of 
I.V.=60. A second dispersion was also prepared but with the amidoamine 
quaternary sourced from a partially hydrogenated soya triglyceride with an 
I.V. of 70. Again a reference or comparative dispersion was prepared using 
an amidoamine quaternary based on tallow triglyceride (I.V.=55). 
The three dispersions were allowed to age for one week prior to softening 
evaluation. Whereas in the previous example the odor and color of the 
dispersion remained substantially the same over time, in the product 
formulated with amidoamine quaternary sourced from partially hardened soya 
triglyceride I.V.=70, the dispersion darkened slightly and had taken on a 
rancid odor. The color and odor characteristics of the other two softener 
dispersions remained substantially the same as when the product was first 
formulated. Because the I.V.=70 sample began to show signs of color and 
odor degradation, this dispersion was not evaluated for softening 
performance. 
Fabric was treated and evaluated as in example 1. The results of evaluation 
are summarized below: 
______________________________________ 
AAQ (Tallow Based) 
AAQ (PH Soya triglyceride I.V. = 60) 
______________________________________ 
Test 1 17% 83% 
______________________________________ 
It will be understood that various modifications may be made to the 
embodiments disclosed herein. Therefore, the above description should not 
be construed as limiting, but merely as exemplifications of preferred 
embodiments. Those skilled in art will envision other modifications within 
the scope and spirit of the claims appended hereto.