Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1999-09-28
2001-06-26
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C570S130000, C570S152000, C570S153000, C570S154000
Reexamination Certificate
active
06251843
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to synthetic detergent bars and detergent compositions which can be shaped into bars.
BACKGROUND
Washing bars can be classified into soap bars, mixed active bars containing a significant proportion of soap and thirdly synthetic detergent bars containing only a small proportion of soap or none at all.
Conventional soap bars comprise a large proportion, typically 60-80% by weight, of fatty acid soap. Fatty acid soaps are selected to provide a balance of soluble and insoluble soaps which provide the required functional properties as regards lather formation and bar structure. Conventional soap bars are manufactured by milling, plodding and stamping a semi-solid mass of soap and other components.
Bars are known which contain a mixture of soap and synthetic detergent where the amount of soap may be less than the amount of synthetic detergent but is nevertheless still a significant contributor to the content of the bar. In such bars, as in conventional soap bars, the content of soap, especially the insoluble soap, contributes to the structure and physical properties of the bar.
The third category is synthetic detergent bars, often known as “Syndet” bars, in which there is no soap or only a small amount and the detergent active is mostly or wholly a synthetic, non-soap, detergent. Generally such bars contain a substantial proportion of material which is not a detergent and which serves to give structure to the bar. Such “structurants” are normally water-insoluble and include such materials as starch and kaolin. The bars frequently also contain a plasticiser: known plasticisers include stearic acid and cetyl alcohol. Known surfactants for Syndet bars include primary alkyl sulphates, alkyl ether sulphates, betaines, sarcosinates, sulphosuccinates and isethionates. These syndet bars containing no soap or only a small proportion of soap are traditionally produced by energetic working of a physical mix of structurant, plasticiser and surfactant, i.e., both the soluble and insoluble components, in a high shear mixer to an end point at which the product is not gritty. The mix is then formed into ‘syndet’ bars.
The known process has several disadvantages in that the physical mixing step is performed batchwise and requires an energetic mixer.
We have now found that by adopting a novel composition, syndet bars may be produced by a process which dispenses with the known energetic working step.
In contrast with prior compositions and processes, the invention relies on ingredients which are molten at conveniently accessible temperatures but which are above the temperatures normally encountered during use of “Syndet” bars. As a result the necessary intimate mixing of the ingredients of the bar can be accomplished by simple mixing while the bar composition is liquid rather than by relying on energetic working to achieve intimate mixing of a mixture of solids.
The present invention further recognizes that it is only a specific class of water-soluble structurants, i.e., those having defined minimum melting points, which can function to partially replace hydrophobic fatty acid structurants normally used in bar structuring.
If the melting temperature is too low, the composition will be too “liquidy”, extruded bar product will be extremely soft and during refining stage, rather than typical “noodles”, large sticky balls will typically form. Yield stress measurements show extremely soft and essentially, from a consumer perspective, useless bar.
If, on the other hand, melting point were too high, the bars would be too sticky to process, have low lather and low dissolution.
In short, the water-soluble structurant must be chosen precisely so as to be not too liquidy, so as to be hard enough to process well, yet not be so hard as to form sticky product which will clog machinery and inhibit processing.
It has never been previously recognized that large amounts (i.e., 20% or greater) of specific water-soluble material (e.g., alkylene oxides) could be used for this purpose because there was no recognition that minimum melting point (i.e., MW) was required. Water soluble materials such as alkylene glycols in the art have traditionally been viewed as “moisturizing” ingredients and the materials used would be generally perceived by the art to be liquidy and to not process well.
U.S. Pat. No. 4,812,253 to Small et al., for example, discloses a composition comprising surfactant (component (a) of the subject invention), water-insoluble structurant such as fatty acid (component (c)) and water (component (d)). Although Small et al. mentions that polyalkylene glycol can be used as “moisturizer/emollient” at levels of 10-40% by wt., there is nothing in this reference teaching or suggesting the melting point or MW be above certain minimum levels (i.e., 40° C. and up, preferably 47°-100° C., more preferably 50° to 100° C.).
Indeed, there are no examples of such “moisturizer” at all and preferred moisturizers are said to be coco and tallow fatty acids. As noted, previous art would not have used high levels of alkylene oxides as structurants because they would have believed the bar was unprocessable or, if processable, would create soft, mushy bars of very low yield strength. Nothing in this or any other reference would have motivated the inclusion of specifically defined water-soluble structurants of the invention.
BRIEF SUMMARY OF THE INVENTION
Accordingly, the present invention provides a detergent composition which is, or can be shaped into, a synthetic detergent bar, the composition comprising:
(a) 10 to 60% by weight of a synthetic, non-soap detergent,
(b) 10 to 60%, preferably 20 to 60% by weight of a water-soluble structurant which is neither soap nor a non-soap detergent and which has a melting point in the range 40° to 100° C., preferably 47° C. to 100° C., more preferably about 50° C. and greater to 100° C.,
(c) 5 to 50% by weight of a water-insoluble structurant which is neither soap nor a non-soap detergent and which has a melting point in the range 40° to 100° C, and
(d) 1 to 20% by weight water, preferably 1% to 14%, more preferably 3% to 12%, more preferably 4% to 11% and most preferably 5 to 10%.
It is desirable that the content (if any) of material other than said synthetic non-soap detergent (a) which does not melt below 100° C. is less than 20% by weight of the composition.
In many embodiments of this invention the content of the synthetic detergent (a) will lie in the range 10 to 50% by weight. Preferably the composition will contain some water, in an amount from 1% to 14% or 15%, preferably 3% to 12%, more preferably 4% to 10%, and most preferably 5% to 10%.
It will be seen from the above, that a significant constituent of a composition according to this invention is a water-soluble material which melts at a temperature in the range 40-100° C., preferably above 46°, i.e., 47° to 100° C., and serves as a bar structurant. Such a material assists in giving the desired properties notably that the bar has a rigid solid form.
It is also be noted from the above that the composition of the bar can tolerate the presence of some material which does not melt at temperatures below 100° C. Such material can also serve as a structurant. Such material is not an essential requirement and it may be entirely absent. If such material is present, the molten composition will not be fully liquid at temperatures of up to 100° C. unless the non-melting material dissolves in the other materials present. We have found that a moderate amount of material which does not melt can be dispersed in the molten composition while it remains sufficiently liquid to be stirred without requiring energetic working. As will be mentioned again below, this material which disperses but does not melt may be at least part of the non-soap synthetic detergent (a) and/or material other than this category.
Suitable synthetic detergents (a) are: alkyl ether sulphates; alkyl ethoxylates; alkyl glyceryl ether sulphonates; alpha olefin sulphonates; acyl taurides; methyl acyl taurates; N-acyl glutamates; acyl is
Chambers John George
Joy Bryan Stuart
Katz Melissa Iva
Sheehan John Gerrard
Koatz Ronald A.
Ogden Necholus
Unilever Home & Personal Care USA , division of Conopco, Inc.
LandOfFree
Synthetic detergent bar and manufacture thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Synthetic detergent bar and manufacture thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synthetic detergent bar and manufacture thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2506167