Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-04-18
2003-10-07
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, C510S141000, C510S133000
Reexamination Certificate
active
06630432
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to bars comprising primarily fatty acid soap as cleansing agent (although relatively small levels of synthetic surfactant are permissible) which bars also contain salts of alpha-hydroxy acids (e.g., sodium lactate).
BACKGROUND
It is greatly desirable to incorporate salts of &agr;-hydroxy acids (e.g., sodium lactate) into soap bar compositions. Sodium lactate, for example, is a molecule which is found in the skin and has humectant properties. Consumer research has identified that presence of such natural moisturizing factors in personal wash products has considerable consumer appeal, especially if associated with a benefit.
Incorporating such salts, which are generally strong electrolytes, into a soap bar, however, can create processing dilemmas. Since these molecules are strong electrolytes, for example, they may easily disrupt the liquid crystal phases of the soap matrix which binds the insoluble soaps together. Without these liquid crystal phases, soap cannot be extruded in any meaningful way.
Unexpectedly, applicants have now found that use of monoglycerides (especially glycerol monolaurate) and/or free fatty acid added to superfat the composition results in stabilization of liquid crystal phases such that a quality soap bar comprising high levels (2% to 15%, preferably 3% to 14%, more preferably 4% to 14% by wt.) of, for example, sodium lactate can be produced. While either superfattying free fatty acid or monoglycerides may be used in the absence of the other, there must be at least 3% by wt. of one, the other or both.
The use of certain moisturizing salts, e.g., lactates and glutamates, in soap based bars is not new. GB Patent 1,487,552 (assigned to Unilever) discloses at page 2, Example II, for example, tallow soap bars which may contain 12%, 15% or 18% sodium lactate. When attempts were made by applicants to extrude such bars, it was found to be extremely difficult (for example, 5 bars per hour or less versus at least 30 bars per hour which can be extruded using bar compositions of invention). This failure is not surprising because the previous patent specification does not teach or suggest use of monoglyceride and/or free fatty acid (and, as noted, minimum 3% of one, the other or combination of two). Thus, there is no recognition of the interaction of the salt with the monoglycerides and/or with free fatty acid and how this interaction leads to the high quality bars of the invention.
JP 83004079 discloses soap compositions comprising lactic acid, lauric acid condensate soap with fatty acid soap. Lactic acid is disclosed in condensation reaction but there is no disclosure of lactic acid or its salt in the final product. As such, there is no reason to believe there may or may not be processing problems and certainly no disclosure of additional components (e.g., monoglycerides and/or free fatty acid) to address these problems.
JP 62199699 discloses use of low levels (%) of lactic acid or sodium lactate to sodium soap base. There is no disclosure of adding ingredient (e.g., monoglycerides such as glycerol monolaurate and/or free fatty acid) to improve processing problems caused by the lactate salts.
JP 07026299 discloses composition comprising soap substrate, 5-50% anionic and/or amphoteric surfactant and mono fatty acid ester. The compositions of the invention comprise less than 10% by wt. synthetic surfactant, preferably less than 5%, more preferably 4% or less, more preferably 3% or less. Further, the Japanese reference does not appear to disclose salt of &agr;-hydroxy acid or to recognize the synergy between the salt and monoglyceride which prevents the salt from affecting processing.
JP 0908767 discloses soap base, at least one clay mineral and at least one of several listed clays. There is no teaching or disclosure of monoglyceride or super-fattying agent and, although sodium lactate is disclosed in a laundry list of moisturizers, there is no teaching or suggestion of interaction of such with monoglyceride and/or free fatty acid.
SUMMARY OF THE INVENTION
Suddenly and unexpectedly, applicants have discovered there is an interaction between salt of &agr;-hydroxy acid (e.g., sodium lactate) and monoglyceride and/or free fatty acid and that, because of said interaction, it is possible to make high quality, extrudable bars comprising said salt of &agr;-hydroxy acid. That is, it is possible to make high quality soap-based bars comprising a desirable moisturizing agent.
More specifically, in one embodiment, the invention comprises a composition comprising:
(a) 40% to 80% by wt. fatty acid soap;
(b) 2% to 15% by wt. of a salt of &agr;-hydroxy acid (e.g., sodium lactate);
(c) 0% to 15% by wt. monoglyceride (e.g., glycerol monolaurate);
(d) 0% to 15% by wt. free fatty acid; and
(e) 7% to 25% by wt. water.
According to the invention and, while not wishing to be bound by theory, it is believed that the monoglyceride or free fatty acid (“superfat”) or the combination of the two (there must be minimum 3% by wt. whether one alone is used or the combination is used) interact with salt &agr;-hydroxy acid so that the salt does not disrupt liquid crystal phases of the soap matrix necessary for extrusion of a good “high quality” bar.
In a second embodiment, the invention comprises a method or process for making a ploddable bar containing &agr;-hydroxy acid by mixing 40% to 80% fatty acid soap, 2 to 15% salt of &agr;-hydroxy acid and water with at least 3% of monoglycerate, free fatty acid or mixtures thereof High quality product has been produced from neutralizing the appropriate fatty acids (e.g., using NaOH) and adding additional ingredients (e.g., glycerol monolaurate and sodium lactate), while molten; or blending alkalimetal lactate and GML to a preformed soap base.
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment, the invention relates to a fatty acid soap composition comprising naturally moisturizing benefit agents such as salt of &agr;-hydroxy acids (e.g., alkali metal lactate). Though these salts normally disrupt formation of liquid crystal phase and make bars extremely friable (e.g., readily crackable and extremely difficult to extrude), applicants have found that combination of monoglyceride (e.g., glycerol monolaurate), free fatty acid or both (although one may be present to exclusion of the other, at least 3% of one, the other or both is needed), allow high quality bars to be extruded. By high quality is meant a bar which can be extruded at least 25 bars per hour. In the absence of GML and/or free fatty acid at minimal levels, the material is uncohesive, powder-like and cannot be extruded.
In a second embodiment, the invention provides a process for making a ploddable bar (i.e., at rate of 25 bars per hour and greater) even where bar comprises relatively high levels of salts of alpha-hydroxy acids. The soap bars may be prepared by either neutralization or saponification. For example, ingredients are heated until molten (e.g., 80° C. or so) and a salt of alpha-hydroxy acid is added (most likely by means of a solution) to molten mixture. The molten mixture and salt combine readily and there is no time limit associated with this addition.
If fatty acid is to be used, it may be introduced into the mixture a number of ways. The fatty acids, for example, may be added directly to the mixer and melted. A second way to introduce fatty acid to the soap is to add an acid (e.g., citric acid) to react with the soap forming fatty acids. Third, if the soap was formed from a fatty acid neutralization, under neutralizing the fat charge can supply the required fatty material. A combination of any or all three of the described methods is also acceptable.
If a single chain length monoglyceride is to be sued, the material may be added to the mixer and molten or may be pre-molten and added to the mixer. If the salt of the alpha-hydroxy acid is in the form of a solution, the monoglyceride may be combined with the solution and then added to the mixer. If the soap base was prepared via saponification, then a fraction of the triglycerides
Farrell Terence James
Francis Keith
Nunn Charles Craig
Koatz Ronald A.
Ogden Necholus
Unilever Home & Personal Care USA division of Conopco
LandOfFree
Processable soap based bars comprising soaps of &agr;... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Processable soap based bars comprising soaps of &agr;..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Processable soap based bars comprising soaps of &agr;... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3174110