Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-05-15
2003-10-21
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S123000, C510S125000, C510S126000, C510S127000, C510S130000, C510S137000, C510S138000, C510S158000, C510S159000, C510S501000, C510S502000, C510S506000
Reexamination Certificate
active
06635607
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to alkoxylated alkanolisostearamides useful as adjuvants to modify the rheological properties of surfactant systems. More specifically, the invention relates to polypropylene glycol hydroxyethyl isostearamide compositions and methods of use to provide unanticipated and exceptional increases in viscosity, especially when used as the sole thickener for a surfactant system.
BACKGROUND OF THE RELATED TECHNOLOGY
Surfactants may be combined in a cleansing system to alter the properties and/or esthetic qualities of the system including rheology. Rheology is the study of how materials deform and flow under the influence of external forces. Viscosity, which is the measure of resistance to flow, is one aspect of the scientific discipline of rheology. One area in which rheological properties are important is related to liquid cleansers and personal care products. The rheological properties of liquid cleansers, such as shampoos, liquid hand cleansers, and industrial cleansers, are a key element of their acceptability in the marketplace. A consumer will purchase these products based on their esthetics or perceived qualities. Even though a product may be otherwise functional, a consumer will often not repurchase a product, if there is the slightest degradation of esthetics compared to the expected profile which includes the thickness and feel of the product.
Desirable properties of surfactants include the ability to increase viscosity (or thicken), maintain color stability, and provide foam boosting and stabilization. Monoethanolamides and diethanolamides are commonly known to provide these characteristics. These are typically added to a cleansing system that includes a primary surfactant which may be cationic, anionic, nonionic, or amphoteric. Surfactants that are frequently used as the primary surfactant in personal care and industrial cleanser products include sodium lauryl sulfate (SLS), sodium laureth sulfate (SLES), ammonium lauryl sulfate (ALS), ammonium lauryl ether sulfate (ALES), alpha olefin sulfonates (AOS) such as 2-alkene sulfonate, 3-hydroxyalkene sulfonate, 4-hydroxyalkene sulfonate, secondary C
14-17
alkane sulfonates (SAS), amine oxides, cocoamidopropyl betaine (CAB), and combinations thereof. Both diethanolamides and monoethanolamides, as will be discussed later herein, have disadvantages associated with their use.
Surfactant compositions, particularly anionic and cationic ones, will frequently include an addition of sodium chloride or other salts to modulate the viscosity of a liquid cleansing system. Typical cleansing systems use between 0.05% and 3% by weight or more salt to control the viscosity to a desired level. SLS and SLES are two commonly employed surfactants that can be thickened with only nonionic surfactants and salt. Economically, it is highly desirable to achieve a rich, thickened formulation with only a minimum amount of surfactants, since water and salt are very inexpensive.
Branched surfactant materials are usually much more difficult to thicken than straight chain counterparts. An example of this is C
14-16
alpha olefin sulfonates, a mixed anionic surfactant which contains a portion of hydroxy branching and another example is secondary (C
14
-C
17
) alkane sulfonates (SAS). The materials are significantly harder to thicken in a traditional manner (using non-ionic surfactants and salt) as compared to the predominantly linear SLS or SLES type surfactants.
Typically, liquid alkyl diethanolamide (DEA) surfactants have been used as foam boosters and thickeners in liquid cleansing systems. One of the most favorable attributes of diethanolamides is their liquidity at room temperature. This allows cleansing products to be manufactured without the additional step of heating the production batch thereby saving the cost of providing the heat energy needed. However, diethanolamides have unfavorable characteristics and are frequently associated with diethanolamines, which can react with nitrogen oxides and sodium nitrite to form nitrosamines, which are known to be carcinogenic. Consequently, diethanolamides are poor choice for inclusion in future surfactant formulations due to possible regulatory considerations.
Cocamide MEA (monoethanolamide) is also known to provide the desired thickening properties. However, monoethanolamides, including cocamide MEA, are not generally a liquid at room temperature and therefore require an additional heating step. Furthermore, it is difficult to incorporate fragrances in monoethanolamides due to their solid state at room temperature. The more desirable method of incorporating a fragrance into a surfactant system, which will include water, is to mix the fragrance with a liquid surfactant first, because the fragrances are frequently oil-soluble and not water soluble.
Individual alkoxylated alkanolamide surfactants for cleansing systems and methods of preparation have been disclosed in a U.S. application Ser. No. 09/793,042, filed Feb. 26, 2001, a continuation of U.S. application Ser. No. 09/334,812 filed Jun. 17, 1999, now abandoned, which is a continuation in part of U.S. application Ser. No. 09/038,736 filed Mar. 11, 1998, all of which are hereby incorporated by reference. These alkoxylated alkanolamides may include capryl, stearic, soy oil, and coconut oil fatty monoethanolamides.
While each of these materials have many useful properties, they have potential drawbacks if used individually as the sole thickener. These potential drawbacks include one or more of the following: poor color stability, poor viscosity increasing performance, or poor foam boosting performance as well as incompatibility with some surfactant systems. One example is polypropylene glycol (PPG) hydroxyethyl caprylamide, which provides excellent color stability and is a good foam booster, but has little viscosity building character. Another example is PPG hydroxyethyl cocamide, which is compatible with nearly all surfactant systems and has good color stability, but does not build viscosity very well in comparison to cocamide MEA, from which it is derived. A third example, PPG hydroxyethyl soyamide (a straight chained unsaturated C
18
derived from soy bean oil) provides viscosity building character, but has poor color stability.
Japanese Laid Open Patent Application No. 8-337560 to Kawaken Fine Chemicals Co., Ltd, also describes propoxylated amides, but does not disclose surfactant compositions that exclude diethanolamides. Furthermore, Kawaken recognizes no difference
Consequently, there is a need to provide a surfactant composition that is substantially a liquid at room temperature, and increases viscosity and foam boosting, while providing color stability and desired rheological properties and does not have the potential to create nitrosamines. Desirably, the surfactant composition may also act as a solubilizer to make added substances soluble in the preparation of either solid or liquid compositions.
SUMMARY OF THE INVENTION
One aspect of the present invention provides a surfactant system that includes a primary surfactant composition and an adjuvant composition that includes poly (C
2
-C
4
) alkylene glycol hydroxy (C
2
-C
3
) alkyl isostearamide, wherein the adjuvant composition is substantially a liquid at room temperature and modifies the rheological properties of the surfactant system. The adjuvant enables the surfactant system to be formulated without the need for mono- and di-ethanolamines or diethanolamides.
Another aspect of the present invention provides an adjuvant composition for modifying the rheological properties of a surfactant system, wherein the adjuvant composition is substantially liquid at room temperature and includes a first surfactant comprising poly (C
2
-C
4
) alkylene glycol hydroxy (C
2
-C
4
) alkyl isostearamide and a second surfactant different than the first surfactant.
A further aspect of the present invention provides a method of thickening a surfactant system that includes at least one primary surfactant. The method includes the step of adding to the surfactant system a
Gormley John L.
Queen Craig B.
Delcotto Gregory
ICI Americas Inc.
Ramstad Polly E.
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