Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
1998-12-16
2002-03-26
Kelly, Cynthia H. (Department: 1774)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S337000, C510S417000, C510S470000, C510S471000
Reexamination Certificate
active
06362156
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to transparent or translucent heavy duty liquid laundry detergent compositions containing polymers (e.g., gums) capable of suspending relatively large size particles (e.g., capsules) while at the same time remaining readily pourable. The suspended particles generally comprise a component subject to degradation (e.g., encapsulated enzymes or bleach) and/or a component not soluble in the heavy duty liquid and which causes an opaque appearance. Through careful selection of polymer/polymers, it is possible to find a polymer suspending system (i.e., a continuous or non-continuous polymer network) which is stable in an ionic (e.g., high surfactant or high electrolyte concentration) environment and which simultaneously provides consumer desirable appearance.
2. Background
For a variety of reasons, it is often greatly desirable to suspend particles in heavy duty liquid detergent compositions. For example, because there are certain components (e.g., bleaches, enzymes, perfumes) which readily degrade in the hostile environment of surfactant containing heavy duty liquids, these components can be protected in capsule particles (such as described, for example, in U.S. Pat. Nos. 5,281,355 and 5,281,356 to Tsaur et al., hereby incorporated by reference into the subject application) and the capsule particles may be suspended in the heavy duty liquid detergents. Other particles which may be suspended include enzymes (whether or not encapsulated) and desirable ingredients (e.g., polyvinylpyrrolidone, aminosilicones, soil release agents, antiredepositon agents, antiwrinkle agents, etc.)
One way to suspend particles in liquid compositions is to use so-called “structured” heavy duty liquids (sometimes referred to in the art as “duotropic” liquids and in contrast to single continuous phase “isotropic” liquids). Structured liquids may be broadly characterized in that they contain high levels of electrolyte and in that the liquids form so-called lamellar layers which are like sheets or plates in close proximity to one other. Structured liquids are well defined in U.S. Pat. No. 5,147,576 to Montague et al., hereby incorporated by reference into the subject application. Such structured liquids, by virtue of their close packing and lamellar sheets, are generally able to suspend particles (e.g., capsules, enzymes, polymers) more readily than isotropic liquids. Structured liquids are often difficult to pour and, because they are lamellar, are generally if not always opaque.
Another way of suspending particles in liquids is through the use of certain structuring gums (e.g., xanthan gum, rhamsan gum and the like). While such gums are desirably used to structure liquids and suspend particles, however, they are notoriously susceptible to electrolytes (e.g., surfactants, electrolyte) present in the compositions and so may generally only be used when the level of surfactant is severely limited (e.g., less than 10% by wt.). By contrast, compositions of the present invention comprise greater than 15%, preferably greater than 17% most preferably 20-85% by wt. surfactant and/or electrolyte. Use of gums and such high levels of surfactant is known to lead to instability/precipitation which in turn leads to non-clear product and to phase separation.
Moreover, when used to thicken compositions, the gum polymers are generally used in such high amounts as to render the compositions very difficult to pour. By difficult to pour is meant greater than about 3000 cps at 21S
−1
shear rate measured at room temperature (measurements of invention were made using Haake RV20 Rotovisco RC20 Rheocontroller; preferred sensor systems were MV1, MV2 and MV3 sensor systems).
As far as applicants are aware, all attempts to suspend particles, particularly large size particles (e.g., greater than 300 to 5000 microns, preferably 500 or greater to 3000 microns) in liquid compositions (preferably isotropic compositions), particularly those containing greater than 15% surfactant, while maintaining pourability have been unsuccessful. In particular, attempts to suspend particles in pourable liquids in a translucent/transparent composition is simply unknown.
U.S. Pat. No. 4,749,512 to Brown et al., for example, teaches suspension of builder salts in automatic dishwashing formulations. The compositions are neither translucent nor transparent. The compositions also contain no water and no polymeric thickeners. The builders are suspended due to surfactant structuring.
U.S. Pat. No. 5,562,939 to Lewis teaches a method using a pre-gel process to suspend particles in liquid. The compositions have no surfactant and a pH of 2.5 to 6, preferably 3.0 compared to much higher surfactant levels (minimum 15% preferably greater 20% by wt.) and pH (about 6 to 13, preferably 8 to 10) of the subject invention.
U.S. Pat. No. 5,597,790 to Thoen teaches suspension of solid peroxygen compounds having particle size of 0.5 to 20 microns in liquid detergents using low levels of silicate. The suspended particles were much smaller than those of the invention.
In “Xanthan Gum: Natural Biogum for Scientific Water Control”, 5
th
Edition, it is taught that biological polymer solutions (e.g., xanthan gum) may be stable up to 20% nonionic or 15% anionic surfactant alone. However, the reference clearly suggests that combinations of surfactant above 20% are unstable while surfactants of the invention may be used in much greater amounts. Further, the reference relates to formation of continuous network only.
WO 97/26315 (assigned to Colgate) discloses transparent containers with specific chromaticity defined by x and y values. It uses specific dyes so that liquid can match the color of the container.
The reference fails to teach or suggest transparent compositions having pourability and particle suspension properties of the compositions of the invention.
Finally GB 1,303,810 discloses clear liquid medium and a visually distinct component of at least 0.5 millemeter particle size. However where more than 10% surfactant is used, only clays, not gums are used to structure. Where a gum is used to structure (Keizan), no more than 10% surfactant is used.
In short, there is no teaching in the art of heavy duty liquid compositions containing 15% or greater, preferably about 20% to 85% surfactant, more preferably 21% to 75% by weight surfactant comprising suspending gum polymers stable in high surfactant environment (e.g., don't phase separate and cause opaqueness) able to suspend large size particles and simultaneously provide translucent/transparent, pourable compositions.
While not wishing to be bound by theory, it is believed these compositions can be formed only because of applicants realization that the suspending polymers (e.g., gums) must be given sufficient time or heat to swell prior to their combination with surfactant and/or electrolyte. Time and temperature are highly dependent on selection of gum but it is critical that the gum be allowed to swell. In addition, for hygienic purposes it is generally desirable to heat the gums to a temperature of about 150° F.
The swollen polymer can then be formed into “suspension bits” (e.g., a continuous interlocking network or as a series of non-continuous gum particles) in the liquid detergent formulation. In other words the swollen gum polymers can “lock” to form one large continuous network or they can be suspended independently in a non-continuous fashion. Each of these processes is dependent on gum section as is described in greater detail in applicants' copending process applications filed on same date as subject application, both of which are hereby incorporated by reference into the subject application. The polymer gum “bits” may be formed prior to combining with rest of liquid detergent formulation or they may be formed in situ.
In any event, because of these pre-swollen (e.g., swollen with water before contact with surfactant and/or electrolyte) “suspension bits”, surprisingly and unexpectedly, it has been found possible to form a tr
Bae-Lee Myongsuk
Buytenhek Cornelis Johannes
Garufi Kim
Hsu Feng-Lung Gordon
Kuzmenka Daniel Joseph
Garrett Dawn
Kelly Cynthia H.
Mitelman Rimma
Unilever Home & Personal Care USA , division of Conopco, Inc.
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