Note: Descriptions are shown in the official language in which they were submitted.
3~
SOFTENING COMPOSITIONS
The present invention relates to softening composi-
tions, more particularly to softening compositions used as
rinse cycle softeners in laundry washing operations.
Rinse cycle softeners have been known for a long time
and are described in a number of patent applications and
articles. Some rinse cycle softeners comprise in their
formulation silicone components. G.B. Patent Specification
1 549 180, for example, describes compositions for treating
fabrics in an aqueous bath such as the final rinse after a
washing process to improve various properties of the
fabric, comprising a fabric substantive cationic compound
and an emulsion of a predominantly linear di(Cl-C5) alkyl
or aralkyl siloxane, having a viscosity of at least
100 mm2/s and up to 8000 mm2/s; the weight ratio of the
siloxane content of the emulsion to the cationic compound
being in the range from 5:1 to 1:100. The compositions
described in said Patent Specification are claimed to
provide easier ironing, anti-static properties, pleasanter
feel of the fabrics and soil release properties.
~etergent compositions have also been developed which
include fabric softening components. It is intended that
these components are carried through to the rinse cycle of
the washing process. However, washing processes usually
have a number of rinse cycles, and the softening composi-
tion should preferably only be released in the last cycle
to ensure maximum effect. The advantage of such detergent
compositions lies in the fact that the user only has to add
one dosage of cleaning materials to ~he washing machine.
Many people still prefer to control the amount of softener
used on specific fabrics. There is, therefore, still a
need for a rinse cycle softener which is to be added at the
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last rinse cycle. Front loading washing machines are
usually provided with a multi compartment feeder tray, in
which detergent dosages for prewash and main wash and
softener compositions can be supplied in different compart-
ments at the onset of the washing cycle, thus onlyrequiring the user to measure ingredients out once per
washing process.
There has been a move towards more concentrated rinse
cycle softener compositions. These have the advantage of
requiring less storage space than the less concentrated
compositions. However, because of the change in formula-
tion as a consequence of concentrating the softener compo-
sitions, there is an inherent oam problem with some of
these compositions when they are introduced in the rinse
cycle of the washing process. It is regarded as aestheti-
cally unsatisfactory to retain a high foam level in the
rinse cycle of a washing process. The user of the washing
machine, particularly the housewife, tends to relate
excessive foam levels in the rinse cycle with inefficient
rinsing. When the washing liquor is drained off at the end
of the washing cycle prior to the first rinsing cycle there
is usually a certain amount of detergent which is carried
through from one cycle to the next. This also causes some
unwanted foaming in the rinse cycle. There is therefore a
need to control the foam in the rinse cycle of the washing
process, more particularly in the last rinse cycle into
which a softener composition is released.
G.B. Patent Specification 2 185 752 describes a
detergent composition which provides rinse cycle suds
control and comprises a surfactant, detergency builder and
rinse cycle suds control prills comprising fatty acid soap,
at least one quaternary ammonium salt and at least one
silicone fluid suds depressor. The silicone fluid suds
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depressor is described as a polysiloxane con-taining
moieties of the general structure -(R'R''SiO)X-, wherein x
has a val~le of from 20 to about 2000 and R' and R" are
alkyl or aryl groups. Such prills are effective in a solid
powder detergent, and rely on the pH of the washing liquor
and subsequent change of pH when entering the rinse cycle
for releasing the components. This means that the composi-
tion will be released, at least in part, from the first
rinse cycle onwards. Liquid rinse cycle softeners also
require a diferent solution to the problem of controlling
foam.
We have now found that improved rinse cycle softener
compositions can be produced by introducing into them a
silicone foam controlling agent, comprising a polydiorgano-
siloxane and hydrophobic solid particles, and a nonionic orcationic suractant which is able to emulsify the foam
controlling compound to some extent.
The invention provides in one of its aspects a rinse
cycle softener composition comprising
A) an organic cationic compound which is substantive to
water rinse on textile fibres,
B) a silicone foam controlling agent, comprising a liquid
polydiorganosiloxane and solid hydrophobic filler
particles,
and
C) a nonionic or cationic surfactant, capable o
emulsifying, at least to some extent, the silicone foam
controlling agent.
As Component (A) of the composition of this invention
there may be employed any organic cationic substance which
is substantive to water rinse on textile fabrics and which
is capable of imparting softness and/or lubricity to
textile fabrics. A large number of such substances is
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known and includes quaternary ammonium compounds such as
(a) alkylmethyl quaternary ammonium compounds having either
one C18-C2~ alkyl chain or two C12-C30 alkyl chains, the
long chain alkyl groups being most commonly those derived
from hydrogenated tallow. Examples of such compounds are
ditallowdimethyl ammonium chloride, ditallowdimethyl
ammonium methyl sulphate, tallowtrimethyl ammonium
chloride, dieicosyldimethyl ammonium chloride, tallowdi-
methyl(3-tallowalkoxypropyl)ammonium chlorid~, ~itetra-
decyldimethyl ammonium chloride, didodecyldiethyl ammoniumacetate and tallowtrimethyl ammonium acetate;
(b) amido a~koxylated quaternary ammonium compounds.
Quaternary compounds of this type can be prepared from
fatty acids or triglycerides and an amine e.g. diethylene
triamine. The product is then alkoxylated with ethylene
oxide or propylene oxide and quaternised with dimethyl
sulphate. Compounds of type (b) can be represented by the
formula
y 2y c
O I O
MC~INCH2CH2 -N-CH2CH2NHC-M X
_ CH3
wherein M represent~ a fatty alkyl group typically C12 to
C20, X represents for example Cl, Br or the methyl sulphate
group, y is 2 or 3 and c is an integer;
(c) quaternised amido imidazolines. Compounds of this type
can be obtained by heating the alkoxylated product of
reacting an amine and a fatty acid or triglyceride as
described for type (b) to effect ring closure to the
imidazoline. This is then quaternised by reaction with
e.g. dimethyl sulphate. An example of a type (c) compound
is 2-heptadecyl-1-methyl-1-(2'-stearoyl amido-ethyl)-
imidazolinium methyl sulphate;
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(d) polyamine salts and polyalkylene imine salts e.g.
[ l~H25NH(CH3)-(CH2)3-NH2C12H25]++[Cl-]2'
[Cl8H37NH(cH3)-(cH2)2-NH(c2H5)2] (CH3S04) 2 and a poly-
ethylene iminium chloride having about 10 ethylene imine
units;
(e) alkyl pyridinium salts e.g. cetyl pyridinium chloride.
The generally preferred organic cationic conditioning
agents are those having long chain, fatty alkyl groups
derived from tallow or hydrogenated tallow and the
generally preferred class of softening agents are those of
type (a), that is the alkylmethyl ammonium compounds.
Fabric conditioning agents which may be employed as
component (A) of the compositions of this invention are
well known substances and have been widely described in the
technical literature, see for example J. Am. Oil Chemists
Soc., January 1978 (Vol 55), pages 11~ - 121 and Chemistry
and Industry, 5th July 1969, pages ~93 - 903.
Component (B) is a silicone foam controlling agent.
These agents are known compounds and are commercially
available. Silicone foam controlling agents which are
suitable for the present invention consist essentially of
polydiorganosiloxane polymers and a solid particulate
filler which has been rendered hydrophobic, preferably a
silica ~iller. The polydiorganosiloxane is suitably subs-
tantially linear and may have the average formulaR[(R2)SiO]XSiR3, where each R independently denotes an
alkyl or an aryl group. Examples of such groups are
methyl, ethyl, propyl, isobutyl and phenyl. PreEerred
polydiorganosiloxanes are linear or substantially linear
polydimethylsiloxanes. Pre~erably they have trimethylsilyl
end-blocking units and a viscosity at 25C of 5 x 10 5 m2/s
to 0.1 m2/s i.e. a value of x in the range 40 to 1500.
These are preferred because of their commercial
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availability, their relative low cost and their suitable
surface energy. The solid filler consists preferably of
silica particles. These may be fumed or precipitated
silica particles or may be made by gel-formation
techniques. The silica particles suitably have an average
particle si~e of from 0.1 to 50 micron, preferably from 1
to 20 micron and a surface area of at least 50m2/g. These
silica particles can be rendered hydrophobic e.g. by
treating them with fatty acids, with dialkylsilyl groups
and/or trialkylsilyl groups either bonded directly onto the
silica, for example by reacting the silica with hydroxy-
endblocked polydialkyl siloxanes, or by means of a silicone
resin, having e.g. SiO2 and R'aSiO4 a units, wherein
each R' is independently an alkyl, aryl or hydroxyl group,
preferably methyl, and a has a value of 1 or 2 or prefer-
ably 3. We prefer to employ a silica, the particles
whereof have been rendered hydrophobic with dimethyl and/or
trimethyl silyl groups. Silicone foam controlling agents,
suitable for use in compositions according to the
invention, have filler from 1 to 50%, preferably 2 to 30%
by weight of the total weight of the silicone foam
controlling agent resulting in a compound having an average
viscosity in the range of from 2 x 10-4 mZ/s to 1 m2/s.
Preferred silicone foam controlling compounds may have a
viscosity of from 5 x 10 m2/s to 0.1 m2/s. The foam
controlling compound may be present as a dispersion of the
filler particles in the polydiorganosiloxane or they may be
provided in the form of an oil-in-water emulsion.
Component (C) of a composition according to the
invention is a nonionic or cationic surfactant, which is
capable of emulsifying component (B) at least to some
extent. Such surfactants include a range of materials,
. ~ _
e.g. quaternary ammonium salts, amine oxides, alkylphenol
ethoxylates, fatty or oxoalcohol polyethylene glycol
ethers, eth-ylene oxide/propylene oxide polymers and fat-ty
alcohol polyglycol ethers. Preferred surfactants are the
nonionic surfactants which have a silicone portion and an
oxyalkylene portion. The most preferred surfactants are
siloxane oxyalkylene copolymers, having a siloxane chain,
which has attached thereto one or more oxyalkylene groups,
for example oxyethylene or oxypropylene groups or a mixture
of both. The oxyalkylene groups are preferably linked to a
silicon atom via an alkylene group. This alkylene group is
for stability reasons preferably a propylene or isobutylene
group, having three carbon atoms between the silicon atom
and the oxyalkylene group. The remaining silicon-bonded
substituents may be hydrocarbon groups having 1 to 18
carbon atoms, which may be substituted with e.g. trifluoro-
propyl groups. Oxyalky]ene groups may be attached to each
end of a linear siloxane chain, thus forming the copolymers
of the ABA form, wherein A represents the oxyalkylene group
and B represents the siloxane chain. Alternatively the
oxyalkylene groups may be pending from the siloxane chain,
thus forming the so-called rake co-polymers. The oxyalky-
lene groups May be end-capped for example with an anion,
e.g. acetate, or they may be left uncapped, thus termi-
nating in a hydroxyl group.
Component (C) surfactants may be present as theemulsifier, or one of the emulsifiers, of the silicone foam
controlling agent when component (B) is added to the
composition of the invention as an emulsion. It is,
however, preferred that they are separate from the silicone
foam controlling agent, or additional to the emulsifier(s)
of the foam controlling agent when the latter is provided
as an emulsion.
gP41~'~
A composition according to the invention may comprise
up to 50~ by weigh~ of component (A), preferably from 5 to
35%. Most preferred are those compositions which are
regarded as concentrated fabric softeners, i.e. having from
12 to 30% of component (A). Component (B) may be present
at 0.01 to 5% by weight of the total composition. It is
preferred that from 0.05 to 1% is used. Higher levels are
also effective but increasing the amount of foam
controlling agent used does not tend to improve the control
of foam any further. Levels below 0.1% will work, but to a
lesser degree. The amount of component (C) used in the
composition of the invention may range from sufficient to
give a stable emulsion of the foam controlling agent, to an
amount equal to about 10 times the amount of component (B)
used. Preferably the ratio of component (B) to (C) is in
the range from 1:1 to 1:5.
The compositions according to the invention may also
comprise other ingredients, for example those which are
conventional in softening compositions. These include
water miscible solvents, perfume, dyes, thickeners, other
emulsifiers, electrolytes, preservatives, optical
brighteners etc. They may also include other organo-
siloxane polymers, for example linear or cyclic polydi-
organosiloxanes which may be present as e.g. as emulsions
or as diluent for the preferred component (C). The
ingredients may be mixed together in conventional ways
using blenders or other homogenising equipment.
The invention also provides a method of softening textile
materials by applying thereto a rinse cycle softener compo
sition comprising a liquid rinse cycle softener composition
comprising (A) an organic cationic compound which is
substantive to water rinse on textile fibres, (B) a
silicone foam controlling agent comprising a liquid
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polydiorganosiloxane and solid hydrophobic filler particles
and, (C) a nonionic or ca-tionic surfactant capable of
emulsifying, at least to some extent, the silicone foam
controlling agent.
There now follow a number of examples which
illustrate the invention~
To a concentrated softener composition (3~1% solids by
weight), which is believed to be based on ditallow or
distearyl dlalkyl ammonium salts, was added 1% by weight of
an emulsion containing 10% by weight of a silicone foam
controlling agent consisting of 88 parts polydimethyl-
siloxane having a viscosity of 1000 mm2/s and 12 parts of a
hydrophobic silica. The emulsifiers used in the emulsion
were glycerol monostearate and a monoester of polyethylene
glycol to form a first example softener.
A second example softener was prepared by adding
instead of the emulsion of the first example, 0.3% by
weight of a mixture of 15 parts of the silicone foam
controlling agent used in the first example, 15 parts of
polydimethyl siloxane polymer and 70 parts of a surfactant
which was a polydimethyl siloxane oxyalkylene copolymer
having 10 mole ~ oxyethylene/oxypropylene units pending in
the siloxane chain, and having a molecular weight of about
28000.
A third example softener was prepared by adding to
the first example softener the copolymer of the second
example softener in an amount giving a ratio of ~.5:1 to
the silicone foam controlling agent.
All three example compositions were tested for their
foam controlling ability. As a comparative test the
softener used in the examples was also tested without the
addition of components (B) and (C), according to the
invention. 3.5kg of clean cotton was washed in a
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conventional front loading washing machine (Miele 433) by
using lOOg of commercially available washing powder which
has no silicone foam controlling agent in it. The washing
cycle used was at 95C. At the fourth (last) rinsing
cycle, 30g of the e~ample softener was added to the machine
in the conventional way, and the foam height was measured
during the rinse cycle. A comparison was also made with a
blank run, using no softener addition in the rinse cycle.
Foam height is measured in % of the height of the window of
the front loading machine which is covered by foam at the
moment the drum is stationary. Results are given in the
following table showing that compositions according to the
invention control the foam of softener compositions
satisfactorily.
TABLE
Test Sample ~ Foam Height
Blank 40
Comparative 70
Example I 45
Example II35
Example III 35
