Note: Descriptions are shown in the official language in which they were submitted.
- 1 - C3416
FABRIC SOFTENING COMPOSITION
The present invention relates to fabric softening
compositions; in particular the invention relates to
aqueous dispersions of biodegradable fabric softening
compositions comprising a water insoluble cationic fabric
softening agent and a nonionic stabilising agent suitable
as rinse-added fabric softener compositions.
Rinse added fabric softener compositions are well known.
Typically such compositions contain a water insoluble
quaternary ammonium fabric softening agent dispersed in
water at a level of softening agent up to 7% by weight in
which case the compositions are considered dilute, or at
levels from 7~ to 50~ in which case the compositions are
considered concentrates. In addition to softening, fabric
softening compositions desirably have other benefits. One
is the ability to confer soil release properties to
fabrics, particularly those woven from polyester fibres.
One of the problems associated with fabric softening
compositions is the physical instability of such
compositions when stored. This problem is accentuated by
having a concentrated composition and by storage at low or
high temperatures.
Concentrates and storage stability at low or high
temperature are however desired by the consumer. Physical
instability manifests as a thickening on storage of the
composition to a level where the composition is no longer
pourable and can even lead to the formation of an
irreversible gel. The thickening is very undesirable
since the composition can no longer be conveniently used.
2C?'~~5~."~
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In the past physical stability of rinse added fabric
softener compositions has been improved by the addition of
viscosity control agents or anti-gelling agents. For
example in EP 13780 (Procter & Gamble) viscosity control
agents are added to certain concentrated compositions.
The agents may include Clo-~a fatty alcohols. More recently
in EP 280550 (Unilever) it has been proposed to improve
the physical stability of dilute compositions comprising
biodegradable, ester-linked quaternary ammonium compounds
and fatty acid by the addition of nonionic surfactants.
With concentrated compositions comprising biodegradable
ester-linked quaternary ammonium compounds the problem of
physical instability is more acute than with traditional
quaternary ammonium compounds.
In EP 0 040 562 (Lesieur Cotelle) a nonionic
emulsifier/stabiliser is added to concentrate~comprising
an ester-linked quaternary ammonium compound to form a
viscous gel. The stabiliser is a C12-14 alcohol ethoxylated
with 9 molecules of ethylene oxide. fihe degree of
branching of the alcohol is not, however, mentioned.
Certain nonionic stabilising agents not only stabilise
concentrated compositions comprising biodegradable
quaternary ammonium compounds but are also environmentally
friendly, in that they show acceptable biodegradability
and are not substantially toxic in aquatic systems.
We have found that the high temperature stability of
compositions containing biodegradable quaternary ammonium
compounds may be improved by the use of selected nonionic
stabilising agents.
20"~~SZ'~
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Thus, according to one aspect of the invention there is
provided a fabric softening composition comprising a water
insoluble cationic fabric softening agent and a nonionic
stabilising agent wherein the water insoluble cationic
fabric softening agent is a quaternary ammonium material
which comprises a compound having two C12_18 alkyl or
alkenyl groups connected to the quaternary nitrogen atom
via an ester link and the nonionic stabilising agent is a
predominantly linear C8 to C2z alcohol alkoxylated with 10
or more moles of alkylene oxide, and in that the nonionic
stabilising agent has a clear phase at a 1% concentration
in water somewhere in the range of 0°C and 45°C and a
Krafft point less than 30°C.
Such compositions show improved high temperature
stability, in particular stability at 37°C.
The nonionic surfactant preferably has a krafft point of
less than 10°C, most preferably less than 5°C. Krafft
point is a term well known in the art, for example from R
J Hunter 'Foundations of Colloid Science', Oxford
University Press, Volume 1 1989 page 571. In general
terms the krafft point of a stabilising material is the
temperature below which the solubility of tha material is
low and no micelles are apparent. At temperatures above
the krafft point the solution is clear, at temperatures
below it the solution is cloudy. Thus a solution of a
material with a krafft point of 5°C will be clear between
at least 5°C and 45°C, while a material with a krafft
point of 45°C will be cloudy between 0°C and 45°C and
only
clear above 45°C.
Preferably the compositions of the invention are liquids
comprising an aqueous base.
20735 't7
- 4 - C3416
A preferred type of ester-linked quaternary ammonium
material for use in the compositions according to the
invention can be represented by the formula:
OOCRz
I
( Rl ) 3N+ ( CHZ ) " CH
I
CHZOOCR2
wherein each R1 group is independently selected from C,_,
alkyl, alkenyl or hydroxyalkyl groups; and wherein each Rz
group is independently selected from C$_28 alkyl or alkenyl
groups; n is an integer from 0-5.
A second preferred type of quaternary ammonium material
can be represented by the formula:
R1
1
R1 - N' (CHZ)" T RZ
I I
( CHz ) 2 T RZ
wherein Rl, n and R~ are as defined above.
0 0
I 1
T is -o-c- or -c-o-.
Preferred materials and their method of preparation are,
for example, described in US 4 137 180 (Lever Brothers).
Preferably these materials comprise small amounts of the
corresponding monoester as described in US 4 137 180 for
c
CA 02073517 1999-09-27
_ ~.
- 5 - C3416
example 1-tallowoxy, 2-hydroxytrimethyl ammonium propane
chloride.
Preferably the level of ester linked quaternary ammonium
compounds is at least 1~ by weight of the composition,
more preferably more than 3~ by weight of the composition;
especially interesting are concentrated compositions which
comprise more than 7~ of ester-linked quaternary ammonium
compound. The level of ester-linked quaternary ammonium
compounds is preferably between 1$ and 80$ by weight, more
preferably 3~ to 50$, most preferably 8~ to 50~.
Suitable nonionic stabilisers which can be used include
the condensation products of C8 - Cz2 primary or secondary
predominantly linear alcohols with 10 or more moles of
ethylene oxide, preferably 15 to 20 moles of ethylene
oxide. The alcohols may be saturated or unsaturated. In
particular *Genapol T-150, Genapol T-200, Genapol C-200
all ex Hoechst AG, *Lutensol ATl8 ex BASF, Genapol C-100
Genapol C-150 & Genapol T-350 ex Hoechst. *Dobanol 91-2.5,
Dobanol 91-5, Dobanol 91-6, Dobanol 91-8 ex Shell.
Preferably the nonionic stabiliser has an HLB of between
10 and 20, more preferably 12 and 20.
Preferably, the level of nonionic stabiliser is within the
range of from 0.1 to 10~ by weight, more preferably from
0.5 to 5$ by weight, most preferably from 1 to 4~ by
weight. The mole ratio of the quaternary ammonium
compound to the nonionic stabilising agent is within the
range from 40:1 to about 1:1, preferably within the range
from 18:1 to about 3:1.
The composition can also contain fatty acids for example
C8 - C2, alkyl or alkenyl monocarboxylic acids or polymers
thereof. Preferably saturated fatty acids are used, in
*denotes trade mark
_ _ _ _ _.__ ____ _ _ _ T
- 6 - ~~~~5~"~ C3416
particular, hardened tallow C16-18 fatty acids. Preferably
the fatty acid is non-saponified, more preferably the
fatty acid is free for example oleic acid, lauric acid or
tallow fatty acid.
The level of fatty acid material is preferably more than
0.1~ by weight, more preferably more than 0.2~ by weight.
Especially preferred are concentrates comprising from 0.5
to 20~ by weight of fatty acid, more preferably 1~ to 10~
by weight. The weight ratio of quaternary ammonium
material to fatty acid material is preferably from 10:1 to
1:10.
The compositions of the invention preferably have a pH of
more than 2.0, more preferably between 2 and 5.
The composition can also contain one or more optional
ingredients, selected from non-aqueous solvents, pH
buffering agents, perfumes, perfume carriers, fluorescers
colourants, hydrotropes, antifoaming agents,
antiredeposition agents, enzymes, optical brightening
agents, opacifiers, anti-shrinking agents, anti-wrinkle
agents, anti-spotting agents, germicides, fungicides,
anti-oxidants, anti-corrosion agents, drape imparting
agents, antistatic agents and ironing aids.
The composition may also contain nonionic fabric softening
agents such as lanolin and derivatives thereof.
The invention will now be illustrated by the following
non-limiting examples. In the examples all percentages
are expressed by weight.
7 _ 2Q~''~35~.'7
C3416
Example 1
Liquid fabric softening compositions were made as follows.
The cationic fabric softening agent, fatty acid (and
nonionic stabilising agent where appropriate) were
premixed and heated together to form a clear melt. The
molten mixture thus formed was added to water at 70°C to
80°C over a period of at least one minute, with constant
stirring to form a dispersion.
The viscosity of the compositions was measured by Haake
rotoviscometer following 1 and 3 months storage at ambient
temperature or at 37°C.
The Krafft point was measured by preparing a 1~ solution
of the nonionic stabilising agent in distilled water and
storing the solution at 5°C for 5 days. The solution was
then heated gradually with stirring until the solution
became clear. The temperature at which the solution
became clear was taken as the Krafft point.
CA 02073517 1999-09-27
.r
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Composition A B C D E F G
HT TMAPC1 11.5811.58 11.58 11.58 11.58 11.58 11.58
Fatty Acidz 1.93 1.93 1.93 1.93 1.93 1.93 1.93
Tallow 11E03. 2.5
Tallow 15E0' 1.5
Tallow 18E05 1.5
Tallow 20E06 1.5
Coco 10E0' , 1.5
*Arosurf 66-e108 1.5
Water and Minors ----- Balance --
---
Viscosity at A B C D E F G
110 s-lmPas
1 month Ambient 164 87 42 17 44 31 80
1 month 37C 161 427 28 24 41 58 53
3 months Ambient 178 72 35 - 39 35 -
3 months 37C 175 735 53 - 38 162 -
-
Krafft point C - 45 <5 <5 <5 35 <5
Clear phase - No Yes Yes Yes No Yes
at 1~ concentrat ion
in water between
0C and 45C.
*denotes trade mark
w CA 02073517 1999-09-27
- 9 - C3416
Notes
1. HT TMAPC is a 1,2 dihardened tallowyloxy-3-trimethyl-
ammonio propane chloride ex Hoescht.
2. is hardened tallow fatty acid, *Pristerine 4916 ex
Unichema.
3. is tallow alcohol ethoxylated with 11 moles of
ethylene oxide.
4. is tallow alcohol ethoxylated with 15 moles of
ethylene oxide.
5. is tallow alcohol ethoxylated with 18 moles of
ethylene oxide.
6. is tallow alcohol ethoxylated with 20 moles of
ethylene oxide.
7. is coco alcohol ethoxylated with 10 moles of ethylene
oxide.
8. is isostearic alcohol ethoxylated with 10 moles of
ethylene oxide.
These results show that addition of selected nonionic
stabilising agents to compositions comprising ester linked
quaternary ammonium compounds counteracts destabilisation
at high temperature to give stable concentrated
compositions.
To show that the Krafft point is critical a composition
similar to B was prepared,with Genapol T-110 (NR), a
narrow range tallow alcohol ethyoxylate, ethoxylated with
*denotes trade mark
- 10 - 2~ ~J~~~~~ C3416
11 moles ethylene oxide. This has a Krafft point <5°C and
gave a stable product. Other ethoxylates with Krafft
points <5°C have also been tested and all give stable
products, in contrast to ethoxylates with higher Krafft
points.
