Cleaning compositions for solid surfaces – auxiliary compositions – Auxiliary compositions for cleaning – or processes of preparing – Textile softening or antistatic composition
Reexamination Certificate
2000-05-12
2001-10-16
Hardee, John (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Auxiliary compositions for cleaning, or processes of preparing
Textile softening or antistatic composition
Reexamination Certificate
active
06303565
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of stabilising the viscosity of fabric softening compositions comprising cationic fabric softening agents and perfume.
BACKGROUND AND PRIOR ART
Fabric softener compositions, especially those added in the rinse, are well known. Typically, these compositions comprise a cationic fabric softening agent and perfume. However, frequently these compositions suffer from problems with viscosity stability during storage, especially at storage at, or above, room temperature. The compositions may also suffer with physical stability during storage. Often this is associated with viscosity stability problem.
This has been found to be particularly problematic in fabric softener compositions comprising relatively high levels of fabric softeners actives, e.g. 8% by weight and above, and, of perfume.
It is known to incorporate one or more additional materials, such as silicones, to reduce wrinkling of the fabric during the rinsing and drying stages of the wash.
For example WO-A-96/15309 discloses the use of a combination of a silicone and a film-forming polymer for this purpose. (C) PCT Typical silicones in this application are polydiorganosiloxanes. In many prior art compositions, the silicones are incorporated in the form of an emulsion, which is a micro-emulsion, that is to say the silicone is present as liquid droplets having a droplet size less than the wavelength of visible light and so the emulsion is substantially transparent. However, in a few cases, they are macro-emulsions (e.g. WO-A-97/31997 and WO-A-97/31998). The silicones before emulsification are those having relatively low viscosities, because it is assumed that those with higher viscosities are more difficult to handle during the process of manufacturing the product and are less suited for anti-creasing performance. WO-A-95/24460 discloses a fabric softening composition which contains from about 0.2% to about 20% of a polydimethyl siloxane having a viscosity from about 2 to 5,000 centi-Stokes (cSt).
Our co-pending British patent application 9911942.2 describes fabric softening compositions comprising a cationic fabric softener and an emulsified silicone which has a viscosity before emulsification of 10,000 cSt to 1,000,000 cSt and is a macro-emulsion, and/or, has a median droplet size in the emulsion of at least 0.2 &mgr;m and is emulsified with an emulsifier comprising one or more cationic surfactants.
However, the above do not disclose how to provide improved viscosity stability upon elevated temperature storage for fabric softening compositions comprising cationic fabric softeners and perfume.
The present invention seeks to address the problems with viscosity stability upon storage at temperatures above. room temperature, in particular between 25° C. but below 40° C.
It has now been discovered that surprisingly good viscosity stability upon storage at temperatures above room temperature can be achieved by formulating concentrated fabric softening compositions with 3.5 to 15% by weight of a silicone which is emulsified with one or more cationic surfactants and which is incorporated in the form of a macro-emulsion and which silicone has a viscosity of from 10,000cSt to 400,000cSt, and/or the emulsified silicone has a median droplet size of at least 0.2 &mgr;m.
References herein to the “emulsified silicone emulsion” are to be construed as being to the emulsion product containing the emulsified silicone. References to the “emulsified silicone” are to be construed as being to the emulsified silicone within the emulsion product that is added to the fabric softening composition.
DEFINITION OF THE INVENTION
Thus according to a first aspect of the invention there is provided a method of improving the viscosity stability upon storage at temperatures of 25° C. or more but below 40° C. of a fabric softening composition comprising:
(a) 8 to 50% by weight of a cationic fabric softening agent; and
(b) perfume;
by the inclusion of 3.5% to 15% by weight of an emulsified silicone, based upon the total amount of the composition, which has been emulsified with one or more cationic surfactants to form a macro-emulsion, with the viscosity of the silicone before emulsification being from 10,000 cSt to 400,000 cSt, preferably from 20,000 cSt to 350,000 cSt, more preferably from 25,000 cSt to 250,000 cSt.
A second aspect of the present invention provides a method of improving the viscosity stability upon storage at temperatures between 25° C. or more but below 40° C. of a fabric softening composition comprising:
(a) 8 to 50% by weight of a cationic fabric softening agent; and
(b) perfume;
by the inclusion of 3.5% to 15% by weight of an emulsified silicone, based upon the total amount of the composition, wherein the median droplet size of the emulsified silicone is at least 0.2 &mgr;m, preferably at least 0.25 &mgr;m, more preferably at least 0.39 &mgr;m, preferably also no greater than 25 &mgr;m and the silicone is emulsified with an emulsifier comprising one or more cationic surfactants.
A third aspect of the present invention provides a fabric softening composition comprising;
(a) 8 to 50% by weight of a cationic fabric softening agent; and
(b) perfume; and
(c) 3.5% to 15% by weight of an emulsified silicone has been emulsified with one or more cationic surfactants to form a macro-emulsion;
wherein the viscosity of the silicone before emulsification is from 10,000 cSt to 400,000 cSt, preferably from 20,000 cSt to 350,000 cSt, more preferably from 25,000 cSt to 250,000 cSt.
A fourth aspect of the present invention provides a fabric softening composition
(a) 8 to 50% by weight of a cationic fabric softening agent; and
(b) perfume;
(c) 3.5% to 15% by weight of an emulsified silicone which has been emulsified with one or more cationic surfactants;
wherein the median droplet size of the emulsified silicone is at least 0.2 &mgr;m, preferably at least 0.25 &mgr;m, more preferably at least 0.39 &mgr;m, preferably also no greater than 25 &mgr;m.
The methods according to the present invention may optionally embody both the first and second aspects of the present invention and compositions of the present invention optionally may embody both the third and fourth aspects.
For the avoidance of doubt, in the context of the present invention, the term emulsified silicone means that the silicone is in emulsion form prior to incorporation in the fabric softening composition but does not necessarily remain in that form in the final product.
The cationic fabric softening agent may comprise one or more cationic fabric softening materials and the emulsified silicone may comprise one or more individual silicone materials.
DETAILED DESCRIPTION OF THE INVENTION
Method
The method of the present invention provides a fabric softening composition having improved viscosity stability upon storage at elevated temperatures, e.g. 25° C. and above, particularly 25° C. and above but below 40° C., e.g. at 37° C., by the addition of 3.5% to 15% by weight of the emulsified silicone described below.
The emulsified silicone may be included in the fabric softening composition at any suitable time during its preparation. The emulsified silicone may be post-added to a fabric softening composition comprising a cationic fabric softening agent and a perfume, e.g. where the composition has been formed as in the following examples. Alternatively, the emulsified silicone may be added to the cationic fabric softening agent and then the perfume added thereto, or, the perfume and softening agent may be added to the emulsified silicone.
The method preferably provides a fabric softening composition comprising a cationic fabric softening agent and perfume (as referred to herein) having viscosity stability upon storage at 37° C. for 43 days or more, preferably 56 days or more. For example, the viscosity does not increase or decrease by a factor of 3, preferably not by more than a factor of 2.5, e.g. not more than a factor of 2 of the initial viscosity, during storage.
Cationic Fabric Softening Agents
Preferably, the cationic fabric softening agen
Clarke David Ellis
Small Samantha
Hardee John
Unilever Home & Personal Care USA, Divison of Conopco, Inc.
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