Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
2000-03-14
2001-09-11
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S450000, C446S450000, C446S447000
Reexamination Certificate
active
06288020
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to detergent compositions and additives used in those compositions. Specifically, the present invention relates to compositions containing &agr;-sulfofatty acid esters that can be additives to a detergent, and methods for making and using the same.
Detergent compositions have been known and used as cleaning agents for many years. See U.S. Pat. Nos. 5,783,540, 5,133,892, 4,219,435, 5,358,655, 4,913,832, 5,324,649, 5,397,494, 4,828,745, 4,588,080, 4,518,516, 5,482,641, 4,569,780, 4,828,749, Re. 32,763, and Re. 32,818, the disclosures of which are incorporated herein by reference. A large number of surfactants have been used with detergents because of their excellent surface-activity characteristics. Recently, interest in &agr;-sulfofatty acid esters (also referred to hereafter as “sulfofatty acids”) has increased due to the superior cleaning properties of these compounds. For example, see U.S. Pat. Nos. 5,681,803, 4,816,188, 5,688,982, 5,475,134, and 5,429,773, the disclosures of which are incorporated herein by reference.
&agr;-Sulfofatty acid esters are typically manufactured as sulfofatty acid salts. These salts also exhibit surface active agent properties. Sulfofatty acid salts can be a mixture of salt forms, typically including mono- and di-salts. For example, methyl ester sulfonate (“MES”) has both mono- and di-salt forms, i.e. mono-sodium MES (“msMES”) and di-sodium MES (“dsMES”). Mono-salts of sulfofatty acids generally have superior washing properties as compared with the di-salt forms. The mono-salts are unstable, however, and react with alkali-containing detergent components to form di-salts. In particular, di-salts form under alkaline conditions at pH values of 9 or greater. For example, mono-sodium methyl ester sulfonate reacts with caustic soda (NaOH) to form a di-salt by the following chemical reaction:
Other bases also catalyze di-salt formation. Moisture and/or humid conditions can accelerate base-catalyzed di-salt formation. Heat, in the presence of moisture or humid conditions, can further accelerate di-salt formation.
The formation of di-salts detracts from the desirability of sulfofatty acids as a detergent additive. As the amount of di-salt increases, the amount of the mono-salt correspondingly decreases. To compensate, more mono-salt of the sulfofatty acid must be added to a detergent mixture to provide the same level of surface active agent performance, which increases the cost and unit size of the detergent. Thus, there is a need for compositions, and methods of making and using such compositions, which limit additional di-salt formation in sulfofatty acids.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a composition that protects &agr;-sulfofatty acid esters from di-salt formation.
It is a further object of the invention to provide a composition, such as a detergent additive, having an inner portion containing at least one &agr;-sulfofatty acid ester and an outer portion that protects the &agr;-sulfofatty acid ester from di-salt formation.
It is another object of the invention to provide a detergent containing such a composition. It is still another object of the invention to provide a method of making such a composition, as well as a method of making a detergent containing such a composition.
The present invention includes compositions having an inner portion containing &agr;-sulfofatty acid ester and an outer portion on any part of the inner portion. Preferably, the outer portion is disposed on any outer surface of the inner portion. More preferably, the outer portion is a coating. The outer portion inhibits di-salt formation by protecting the sulfofatty acid from base-catalyzed di-salt formation, and from substances or conditions, such as moisture alone or in combination with an elevated temperature, which accelerate or increase di-salt formation. Such protection can occur by physically or chemically blocking the sulfofatty acid from exposure to substances or conditions which cause di-salt formation, or by neutralizing di-salt forming substances before they interact with sulfofatty acid. By providing such protection, the invented sulfofatty acid composition beneficially extends the useful life of &agr;-sulfofatty acid ester after its manufacture, during shipping and storage, and/or as a detergent ingredient.
In another embodiment of the present invention, the inner portion contains one or more other detergent components. Suitable detergent components are those that do not promote more than a minor amount of di-salt formation when in the presence of sulfofatty acid. For example, detergent components such as other surfactants or non-basic salt may be mixed with sulfofatty acid to form the inner portion.
In any of the embodiments of the present invention, the sulfofatty acid may be a methyl ester sulfonate, and more preferably a sodium methyl ester sulfonate. The shape of the composition—such as a tablet, cylinder or sphere—may be chosen according to the method of making, or intended use of, the composition, as will be appreciated by those skilled in the art.
The present invention further includes methods of making compositions containing at least one &agr;-sulfofatty acid ester. Such methods generally include providing an inner portion containing at least one &agr;-sulfofatty acid ester and providing an outer portion on any part of the inner portion. Preferably, the outer portion is disposed on any outer surface of the inner portion. More preferably, the method includes forming an inner portion containing at least one &agr;-sulfofatty acid ester and applying an outer portion on outer surface of the inner portion. In any of these methods, the outer portion protects or inhibits the at least one &agr;-sulfofatty acid ester from di-salt formation.
The outer portion preferably covers the inner portion. It is not required, however, that the outer portion cover the entire surface of the inner portion. The outer portion can be formed on any part of the inner portion. Preferably, the outer portion can be formed on any part of the outer surface of the inner portion. Techniques for applying the outer portion to the inner portion include, but are not limited to, spray coating, dip coating, spin coating, and spray-drying. Suitable methods of spray drying include counter-current and co-current methods. Another technique for applying the outer portion is agglomeration, in which the inner portion is mixed with an outer portion material to form the invented composition.
The present invention also includes methods for manufacturing detergents, or parts of detergent formulations, using a composition containing at least one &agr;-sulfofatty acid ester. One method includes providing a composition having an inner portion containing at least one &agr;-sulfofatty acid ester and mixing the composition with at least one detergent component. A more preferred method includes providing a composition having an inner portion containing at least one &agr;-sulfofatty acid ester and an outer portion, and mixing the composition with other detergent components to form a detergent or a part of a detergent formulation. Methods of mixing the invented composition with detergent components can include dry-blending, post-adding, agglomerating or spray drying the sulfofatty acid composition with such other detergent components. For example, a detergent can be made by providing a suitable amount of the invented composition containing at least one &agr;-sulfofatty acid ester and mixing it with other detergents components, including soaps, other surfactants, and/or alkaline material(s), by dry-blending. Dry blending or post-adding are the preferred methods of mixing.
DETAILED DESCRIPTION OF THE INVENTION
The following description provides specific details, such as materials and dimensions, to provide a thorough understanding of the present invention. The skilled artisan, however, will appreciate that the present invention may be practiced without employing these specific details. Indeed
Huish Paul Danton
Jensen Laurie A.
Libe Pule B.
Huish Detergents, Inc.
Ogden Necholus
Townsend and Townsend / and Crew LLP
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