Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions
Reexamination Certificate
2002-05-03
2003-10-28
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
C424S070270, C424S070280
Reexamination Certificate
active
06638497
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to the fields of chemistry and personal care products and provides additives which are useful and convenient for formulating shampoos, conditioners and the like, as well as methods of providing same.
BACKGROUND OF THE INVENTION
Fatty ammonium quaternary compositions (hereinafter “quats”) are useful additives to hair care products such as shampoos, conditioners and the like. U.S. Pat. No. 4,891,214 issuing to Stevens et al. on Jan. 2, 1990 provides an informative background into quats and their uses.
In the hair care industry, it is desirable to provide quats in compounds and formulations having a high cationic activity (i.e., relative high concentration of quats to water/solvent mixture). It is also desirable to produce compounds and formulations that, in addition to having a high cationic activity, provide for ease in commercial handling and storage. This is easier said than done. Quats, to be most useful as an additive, should be in the form of a flakeable solid. For the purposes of this application, the term “flakeable” is used to describe the products of processes such as flaking and pastillation.
Achieving the desired high cationic activity while maintaining the product in the liquid state is generally not feasible. Even in the case of compositions using a relatively short chain quat (i.e., a C
16
(16 carbons) fatty chain monoalkyl quat), with water as a solvent, the maximum cationic activity is about 30%. This is the limit for most quats in the liquid state. The cationic activity decreases significantly as the chain lengths increase. Further, the shipping and use of such dilute solutions of quats are undesirable. Finally, high volumes of materials will be required to obtain the necessary quat content in hair care products. This increases total volume, package size, weight, etc.
To boost the cationic activity, and therefore the quat content, other solvents have been tried. Mixtures of water and short chain normal alcohols, for example, produced improved results. Use with, for example, IPA (isopropyl alcohol) increased the cationic activity potential dramatically. In fact, with certain quats, cationic activities as high as about 85% could be realized.
While these products exhibit the desired cationic activity, the normal alcohols are volatile organic solvents (solvents with a boiling point of 85° or lower) which raise significant environmental and safety concerns, both for the consumer and for the company formulating the personal care product. This volatility makes these products less commercially viable. Therefore, it is desirable to find other, non-volatile solvent systems which exhibit the same potential for high cationic activities.
Another potential solvent system utilizes fatty alcohols as opposed to the volatile normal alcohol/water mixtures. Fatty alcohols do not share the same problem with volatility that plagues normal alcohol/water solvent mixtures. In fact, fatty alcohols such as cetearyl alcohol (a mixture of cetyl and stearyl alcohol) have been used as quat solvents. The use of fatty alcohols as solvents has a number of advantages. First of all, many hair care and cosmetic products would have included some amount of fatty alcohols anyway. Also, these quat formulations can be flakeable.
However, as one attempts to boost the effective cationic activity in the formulation, namely the amount of quat used, and as the chain length of the quats and/or the fatty alcohols used increases, so too do the handling problems. In order to effectively handle and, ultimately, flake the material, it must often be heated to a point near, or above, its melting point. This melting point is typically over 100° C. and at that temperature, the quat can begin to degrade. Viscosity also becomes a dramatic stumbling block to formulating end products. For example, using a quat raw material in a fatty alcohol solvent at about 25% cationic activity and assuming it was desired that the finished product would have a 1.5% effective cationic activity, one would need to use 6% by weight of the product (1.5% divided by 0.25 equals 6%). At that level, the relatively high content of fatty alcohol tends to dramatically increase the viscosity of the finished product.
The viscosity/handling problems significantly increase the costs associated with using fatty alcohols as a solvent and the effectiveness of the resulting product. This effectively renders the use of fatty alcohols as a solvent not commercially feasible.
These problems are further complicated at higher cationic activities, longer chain fatty alcohols and/or longer chain fatty quats. These complications, coupled with the addition of other traditional additives to personal care products including emollients and conditioners typically have a further negative impact on commercial handling properties. Their addition in combination with the alcohol/quat mixture will only exacerbate the problem.
Thus, as can be readily understood, while fatty alcohols can provide the desired cationic activities, they do so at the expense of commercial feasibility due to the described viscosity/handling problems.
Another potential solvent system is one comprised of glycols. Glycols such as low molecular weight, short chain alkylene glycols, both normal and branched, can be effective solvents. Glycols offer several advantages. Specifically, they allow for relatively higher concentrations of cationic activity, a lower melting point than the fatty alcohol solvent systems, and do not tend to elevate the viscosity undesirably, at least not to a level comparable to the fatty acids.
However, glycols also have a number of drawbacks. First, quats containing glycols as a solvent generally result in formulations which are not flakeable. Instead, they form a somewhat viscous, waxy, “gummy” solid. While this material may have a lower overall melting point than the fatty alcohol based solvent quats, the overall handling problems involved from this material are significantly greater.
In particular, a drum of this material would most likely require heating for several hours or even days under moderate heat to place it in a state where it can be pumped and handled. The material must then be melted further to a usable form taking time and considerable cost in energy. Flakes, on the other hand, can merely be dumped into a vat and are easier to handle, measure and the like.
In sum, each attempt to increase the cationic activity while obtaining desirable commercial handling properties falls short in one aspect or another. Use of water as a solvent results in low cationic activity. Use of normal alcohols as a solvent results in high organic volatility. Use of fatty alcohols as a solvent results in viscosity problems which require heating the resulting product to a point in which the quats begin to degrade. Use of glycols as a solvent results in a product which is not flakeable. Until now, there existed no quat compound or composition which exhibits all of the favorable properties described above.
SUMMARY OF THE INVENTION
It has been discovered that by producing a solvent mixture of fatty alcohols and glycols, one can achieve many of the advantages of both without many of the disadvantages realized by the use of either. This is contrary to the common understanding that both fatty alcohols and glycols, when used by themselves, as solvents exhibit substantial commercial handling problems.
Utilizing the mixture of fatty alcohols and glycols as a solvent according to the present invention, one can achieve higher cationic activities. For a C
16
fatty quat, for example, one can obtain cationic activities as high as 50 or 60%. At longer fatty chain length based quats, 40 to 50% activity may be the maximum.
In addition, quats containing a mixture of fatty alcohols and glycols as a solvent generally result in formulations which are flakeable. The melting point of the resulting flakeable material is also generally low enough that it can be melted conveniently without a likelihood of damaging the quat. Most preferably, this can be done at commercia
Barinova Helena S.
Nikolopoulos Kostas
Pereira Abel G.
Croda Inc.
Lerner, David, Littenbery, Krumholz & Mentlik, LLP
Ware Todd D
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