Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-06-01
2003-01-21
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Solid, shaped macroscopic article or structure
C510S447000, C510S450000, C510S357000, C510S428000
Reexamination Certificate
active
06509310
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to compositions. Specifically, the present invention relates to compositions containing c-sulfofatty acid esters and methods of making and using the same.
Detergent compositions have been known and used as cleaning agents for many years. (See, e.g., U.S. Pat. Nos. 5,783,540; 5,482,641; 5,397,494; 5,358,655; 5,324,649; 5,133,892; 4,913,832; 4,828,749; 4,828,745; 4,588,080; 4,569,780; 4,518,516; 4,219,435; Re. 32,763; and Re. 32,818; the disclosures of which are incorporated herein by reference.) Surfactants are included in detergents due to their excellent surface-activity characteristics. Typical surfactants include anionic, nonionic and cationic surfactants, those described in Surface Active Agents, Volumes I and II by Schwartz, Perry and Berch (New York, Interscience Publishers), Nonionic Surfactants ed. by M. J. Schick (New York, M. Dekker, 1967), and in McCutcheon's Emulsifiers & Detergents (1989 Annual, M. C. Publishing Co.), the disclosures of which are incorporated herein by reference. Such surfactants are used singly or in combination, according to the desired properties of the resulting composition.
Recently, a-sulfofatty acid esters (also referred to hereafter as “sulfofatty acids”) have gained attention due to the improved cleaning performance of these surfactants. (See, e.g., U.S. Pat. Nos. 5,616,781; 5,637,758; 5,681,803; 5,945,394; and 6,057,280, the disclosures of which are incorporated herein by reference.) &agr;-Sulfofatty acid esters are typically manufactured as sulfofatty acid salts, which also exhibit surface active agent properties. &agr;-Sulfofatty acid ester salts are usually formed as a mixture of salt forms, such as mono- and di-salts. For example, sodium methyl ester sulfonate (“sMES”) can be a mixture of mono-sodium MES (“msMES”) and di-sodium MES (“dsMES”). While mono-salts of &agr;-sulfofatty acid esters have the desired surface active agent properties, di-salts have several undesirable properties that degrade the performance of the &agr;-sulfofatty acid ester. For example, the Kraft point of a C
16
methyl ester sulfonate di-salt is 65° C., as compared to 17° C. for the mono-salt form of C
16
MES. (The Kraft point is the temperature below which surfactants form precipitates instead of micelles; at the Kraft point, the solubility of an ionic surfactant is equal to its critical micelle concentration.) Di-salts also increase the sensitivity of the surfactants to hard water. The resulting poor di-salt solubility in cool and even slightly hard water is a disadvantage in most applications. Generally, significant amounts of di-salt in otherwise high quality &agr;-sulfofatty acid ester degrade the performance of the &agr;-sulfofatty acid ester.
Mono-salts of &agr;-sulfofatty acid esters are unstable and react with basic substances, in the presence of moisture, to form di-salts. For example, msMES reacts with caustic soda (NaOH) in the presence of water to form a di-salt by the following chemical reaction:
Basic materials in detergents also react in a similar manner to form di-salts. Because the formation of di-salts degrades the performance of the &agr;-sulfofatty acid ester, more mono-salt must be added to the composition to provide the same level of surface active agent performance. Such supplementation increases the cost and unit size of the detergent. Accordingly, there is a need for &agr;-sulfofatty acid ester-containing compositions that reduce additional di-salt formation by the &agr;-sulfofatty acid esters, and for methods for making and using such compositions.
SUMMARY OF THE INVENTION
The present invention provides compositions, and methods for making and using such compositions, containing at least one &agr;-sulfofatty acid ester in a first (ester) portion and at least one basic material in a second (basic) portion. These separate portions are combined to form a composition, according to the present invention. The portions are joined to minimize contact between the &agr;-sulfofatty acid ester and basic materials, thereby reducing formation of additional di-salts.
In one embodiment, the composition comprises a first portion containing at least one &agr;-sulfofatty acid ester and a second portion containing at least one basic material, with minimal contact between the sulfofatty acid and the basic material. The &agr;-sulfofatty acid ester is typically a sodium methyl ester sulfonate. The basic material is a compound that causes hydrolysis of &agr;-sulfofatty acid ester by directly interacting with the &agr;-sulfofatty acid ester or by causing a change to higher (basic) pH values, which causes the &agr;-sulfofatty acid ester to hydrolyze. Such basic materials generally include zeolites, phosphates, silicates, carbonates, caustic soda, borate salts, and the like.
Contact between the (&agr;-sulfofatty acid ester in a first portion and the basic material in the second portion is minimized by an intermediate portion between the first and second portions, by a boundary layer at the interface of the first and/or second portions, by minimizing the surface area of the interface between the portions, and/or adjusting the concentration of the &agr;-sulfofatty acid ester and/or basic material in the first and/or second portions, respectively.
The invention also provides methods for making compositions by providing a first portion containing at least one &agr;-sulfofatty acid ester, providing a second portion containing at least one basic material, and joining first and second portions while minimizing contact between the &agr;-sulfofatty acid ester and the basic material. The &agr;-sulfofafty acid ester can be a sodium methyl ester sulfonate. Such basic materials generally include zeolites, phosphates, silicates, carbonates, caustic soda, borate salts, and the like. Contact between the &agr;-sulfofatty acid ester and the basic material can be minimized by providing an intermediate portion between the first and second portions, by providing a boundary layer at the interface of the first and/or second portions, by forming the detergent composition in a shape minimizing physical contact between the portions, and/or by adjusting the concentration of the &agr;-sulfofatty acid ester and/or the basic material in the first and/or second portions, respectively.
DETAILED DESCRIPTION OF THE INVENTION
The following description provides specific details, such as dimensions and materials, to provide a thorough understanding of the present invention. The skilled artisan will understand, however, that the present invention can be practiced without employing these specific details. Indeed, the present invention can be practiced in conjunction with fabrication techniques conventionally used in the detergent industry. Moreover, the processes below describe only steps, rather than a complete process flow, for manufacturing detergent compositions.
A preferred embodiment according to the present invention comprises at least two portions. The first portion comprises at least one &agr;-sulfofatty acid ester, and the second portion comprises at least one basic material. The composition is formed joining the first and second portions while minimizing contact between the &agr;-sulfofatty acid ester and the basic material.
The First (Ester) Portion
In a preferred embodiment, the first portion comprises at least one &agr;-sulfofatty acid ester. Suitable &agr;-sulfofatty acid esters include linear or branched esters of a carboxylic acid (e.g., a fatty acid) that is sulfonated. The &agr;-sulfofatty acid ester also includes those described in U.S. Pat. No. 5,945,394, the disclosure of which is incorporated herein by reference.
The &agr;-sulfofatty acid ester is typically of the following formula (I):
where R
1
is a linear or branched alkyl group, R
2
is a linear or branched alkyl group, and R
3
is hydrogen, a halogen, a mono-valent or di-valent cation, a metal, or an unsubstituted or substituted ammonium cation. R
1
can be a C
4
to C
24
alkyl group including a C
10
, C
12
, C
14
, C
16
, and/or C
18
alkyl
Fredrickson Mark J.
Huish Paul Danton
Jensen Laurie A.
Libe Pule B.
Huish Detergents, Inc.
Ogden Necholus
Townsend and Townsend / and Crew LLP
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