Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-01-26
2001-07-03
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...
C510S153000, C510S155000
Reexamination Certificate
active
06255265
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to predominantly soap bars, particularly those having little or no synthetic surfactant which process well while maintaining consumer desirable properties such as good color, good odor and good slip properties.
BACKGROUND OF THE INVENTION
Bar compositions comprising soap, synthetic surfactant (e.g., acyl isethionate), free fatty acid and organic salts (e.g., sodium isethionate, sodium citrate) are known in the art.
U.S. Pat. No. 4,663,070 to Dobrovolny et al. and U.S. Pat. No. 4,695,395 to Caswell et al. for example, teach such compositions comprising 30% to 70% by wt. neat soap, 5% to 45% acyl isethionate, free fatty acid and sodium isethionate. By contrast, however, the amount of synthetic surfactant used in the compositions of the subject invention is less than 5%, preferably less than 4%, more preferably less than 3%, more preferably less than 2%, most preferably less than 1% by wt. and may be absent altogether. The amount of synthetic used in Dobrovolny is much higher.
U.S. Pat. No. 5,030,376 to Lee et al. also claims cleaning compositions comprising 20 to 80% fatty acid soap (mixture of tallow and coconut), 10% to 60% by wt. C8 to C18 fatty acyl isethionate and 1% to 6% by wt. electrolyte (e.g., organic salt) which may be sodium isethionate. Also, 1 to 20% free fatty acid is in the composition. Again, the synthetic surfactant comprises at least 10% by wt. composition in contrast to the amount of synthetic in the compositions of the invention being under 5%.
GB Patent 2,317,396 (to Cussons Int.) teaches bars with 30 to 90% soap, 1% to 35% secondary surfactant and combination of at least two materials which may be fatty acids, fatty alcohol and hydrocarbons of melting point above 25° C. (e.g., paraffin). There is no teaching or suggestion of adding the organic salts of the present invention in the GB patent.
In applicants copending application to Chambers et al., filed with British priority on Feb. 23, 1998, there is taught a specifically identified alkali metal soap; 3 to 35% fatty acid; 2 to 25% structurant; and water. There is no teaching of organic salts such as sodium isethionate or any teaching of the relationship between such salts and fatty acid in providing consumer benefits (as noted below).
Since synthetic surfactants (e.g., acyl isethionate, alkyl glycerol ether sulfate) are generally much milder than soap, one of the main reasons synthetic surfactant has been added to soap bars is to produce milder bars. The problem is that synthetic surfactants are also generally more expensive than soap.
One way of reducing the cost associated with synthetic surfactants is to replace some of the synthetic surfactant with free fatty acids. Such bars are known as superfatted bars. Unfortunately, substituting free fatty acid for synthetic surfactant, while this does possibly enhance mildness, may lead to the creation of bars with poorer user properties. Specifically, bars superfatted with long chain fatty acid, in the absence of the specific organic salts of the invention, tend to be tacky (e.g., extremely sticky, either to hands or equipment), to have noticeable discoloring and to have low lather.
In addition, a person of ordinary skill in the art would be disinclined to use any electrolyte (e.g., the specific organic salts of invention) in predominantly soap bar compositions because high (i.e., greater than 1%) levels of any electrolyte (e.g., organic or inorganic salts) have historically proven detrimental to the processability of these bars. Specifically, at high levels of, for example, sodium chloride, there is no cohesiveness between soap flakes formed when the flakes are extruded and the bars formed tend to become very brittle and “cracked” (see Comparative Examples 4 and 5). It should be noted that although higher levels of electrolyte are known in some bars (see, e.g., U.S. Pat. No. 5,894,172 to Taneri et al.), these are freezer bars made by a completely different process than flaked/extruded bars of subject invention. Further, the bars have much higher water content (e.g., at least 15%). Finally, this reference does not appreciate criticality between organic and non-organic salts at higher, partially fatty acid levels.
In short, in the absence of the specific organic salts of the invention, there is no incentive to replace synthetic surfactant with free fatty acids because bars with little or no synthetic surfactant have poor user properties (especially in presence of a large amount of free fatty acid); yet there has been no incentive in the art thus far (in fact there has been teaching away) from using electrolyte of any kind (including organic salts) in such bars because high levels of electrolyte (e.g., inorganic alkali metal salts) are known to cause brittle bars which are difficult to process, e.g., in a typical extruded bar process.
BRIEF SUMMARY OF THE INVENTION
Unexpectedly, applicants have now found that the use of specific organic salts (i.e., sodium isethionate, sodium citrate, sodium acetate) in such super-fatted, low synthetic surfactant compositions allow bars to be processed which are high lathering, have excellent bar slip, are low in mush, show excellent extrusion and stamping characteristics, and are generally milder than commercially marketed superfatted soaps (i.e., soap that generally tends to have larger amounts of free fatty acid). The bars are equivalent in consumer characteristics to currently marketed bars (i.e., Lever 2000®) which contained appreciable levels (at least 10%) of synthetic surfactant. The bars of the invention are less expensive (e.g., use less synthetic surfactant) and can be processed using standard soap processing equipment.
Since high levels of organic salts are used, minimum threshold levels of free fatty acid are required to ensure processability and user characteristics. In a preferred embodiment of the invention, the level of fatty acid is at least equal to the amount of organic salt; and the free fatty acid is more preferably a longer chain fatty acid (C16-C22). Mixtures of free fatty acid are of course contemplated and, when used, it is preferred the fatty acid mixture be predominantly (75%, preferably greater than 60%, more preferably greater than 50%) longer chain acid. The invention further contemplates use of 0 to 30%, preferably 5 to 20%, more preferably 7 to 15% water soluble benefit agent (e.g., polyalkylene glycol).
Specifically, the invention comprises (all percentages, unless otherwise noted, are by weight):
(1) about 50% to about 80%, preferably about 55%, more preferably greater than about 60% soap to about 80% soap;
(2) about 4% to 35%, preferably about 5% to 30%, more preferably 5% to 25%, more preferably 6% to 25%, more preferably 6% to 20% by wt. free fatty acid, where the free fatty acid is C8-C22, preferably C12-C18, more preferably C16-C18 fatty acid;
(3) about 1% to 10%, preferably 2% to 10%, preferably 3 to 7%, more preferably at least 4 or 5% organic salt, preferably selected from the group consisting of alkali metal isethionate, alkali metal citrate, alkali metal acetate and mixtures thereof;
(4) 0% to 20% benefit agent; and
(5) 0% to 30%, preferably 5% to 20%, more preferably 6% to 15% by wt. polyalkylene glycol,
where said composition comprises less than 5%, preferably less than 4%, preferably less than 3%, more preferably less than 2%, more preferably less than 1% and preferably no synthetic surfactant.
In preferred embodiments of the invention the polyalkylene glycol helps lessen amount of free fatty acid (e.g., 5-20% polyalkylene glycol and 4-10% free fatty acid) while retaining good consumer attributes (e.g., skin feel etc.) comparable to use of bar with more fatty acid but having no polyalkylene glycol.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to superfatted soap bar compositions (bars comprising predominantly soap and super-fatted with free fatty acid) containing low levels (less than 5%) of synthetic surfactant while maintaining low tackiness, good color and good lather.
The bars of the invention comprise a
Corr James Joseph
Podgorsky Joseph
Sheehan John Gerard
Van Gunst Edward Andrew
Koatz Ronald A.
Lever Brothers Company Division of Conopco, Inc.
Ogden Necholus
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