Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2002-09-03
2004-06-08
Mruk, Brian P. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S360000, C510S392000, C510S421000, C510S424000, C510S475000, C510S492000, C510S505000, C510S535000, C008S137000
Reexamination Certificate
active
06746997
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
FIELD OF THE INVENTION
This invention relates to a process for the preparation of mixed ethoxylated alkylphenol/ethoxy sulfate surfactant systems, to the surfactants thus produced, and to synthetic detergent formulations incorporating the same. In particular, it relates to the preparation of ethoxylated alkylphenol/sulfated ethoxylated alkylphenol surfactant blends providing low cost, low capital, low-energy intensive laundry detergents which exhibit both good cleaning and sudsing characteristics.
BACKGROUND OF THE INVENTION
The manufacture and use of synthetic laundry detergents containing mixtures of nonionic and anionic surfactants has been documented in the patent literature. See, for example, Bonaparte et al. U.S. Pat. No. 3,920,586 and Lengyel et al U.S. Pat. No. 4,464,292 (both of which are incorporated herein by reference in their entirety). Moreover, the use of ethoxylated alcohols (referred to herein, for convenience, by the “EA” acronym) as the nonionic constituent of such mixtures, and ethoxy sulfates (referred to herein by the “ES” acronym) as the anionic constituent of such mixtures has also been described (see the aforesaid Bonaparte patent, column 2, lines 32-37; column 3, lines 17-28; column 9, lines 30-45; and column 9, line 67 column 10, line 20).
Dry blended laundry detergents containing such EA/ES or other nonionic/anionic surfactant systems are further described, for example, in Winston et al. U.S. Pat. No. 4,265,790 (incorporated herein by reference. In the past, however, when for cost purposes EA's have been utilized as the nonionic constituent of such surfactant systems, the sudsing characteristics of the resulting dry blended detergent formulations have been impaired. Moreover, the use of EA/ES surfactant systems in dry blended detergent powders has been said to interfere with the processing characteristics thereof. Various efforts have been made to improve such processing characteristics. See, for example, Kowalchuk U.S. Pat. Nos. 4,137,197, and 4,162,994, both of which are incorporated herein by reference.
It has also been suggested in the patent literature that EA/ES mixtures useful in detergent compositions may be prepared by the direct sulfation of various EA materials. See, for example,
Roele U.S. Pat. No. 3,309,392, and Harris U.S. Pat. No. 3,959,186 (both incorporated herein by reference). The Roele patent describes a two-stage, gas phase reaction for the sulfation of EA's having at least 8 carbon atoms with sulfur trioxide/inert gas mixtures. The final products, which are said to be useful as detergents, wetting agents or the like, are sulfated with conversions ranging from 87 to 97%.
The Harris patent, on the other hand, describes the sequential partial sulfation of, first, a highly ethoxylated EA (incorporating from 8 to 25 moles of ethoxylate per mole of the alcohol) and, thereafter, a less ethoxylated compound (incorporating from 2 to 12 moles of ethoxylate per mole of alcohol, but at least 4 ethoxylate groups per mole less than the EA first sulfated). Harris further discloses that, after neutralization of the partial sulfate mixture thus produced, the resulting product may contribute both detergent and builder properties to dry detergent formulations. Detergents incorporating the same are said to be capable of dispersing lime soap and to possess satisfactory washing characteristics as compared with other commercial dry powder detergents.
Lengyel et al, U.S. Pat. No. 4,464,292 discloses sulfation of (a) a blend of an alcohol and an alkyl ethoxylate or (b) a blend of an alkylaryl-OH (AAr) and an alkylarylethoxylate (AArE) and the use of the blend of the sulfated and unsulfated product which results in laundry detergents. While Lengyel mentions the degree of ethoxylation generally can be from 1-12 ethoxy units, only the alkyl ethoxylates are mentioned specifically with ethoxylations of less than 8 units. The only alkylaryl-O-ethoxylates mentioned have 8-10 ethylene oxide units per mole of alkylaryl-OH.
Although the art surfactant systems provide workable laundry detergent products, the laundry detergent area is a very cost conscious field and there are always efforts at developing lower cost alternatives that provide the same or better cleaning products. In addition, cost savings are also sought in manufacturing processes by eliminating steps or reducing energy demands, etc. meeting these goals takes on additional challenges when dealing with liquid formulations as components which might not interact when in a powder formulation may adversely interact in liquid formulations. Furthermore, liquid formulations may separate on storage, especially when subjected to extremes of temperature as may be encountered in the normal commercial distribution chain.
OBJECTS OF THE INVENTION
It is among the objects of the present invention to provide an improved process for the preparation of mixed AArE/AArES surfactants, which process may be efficiently and inexpensively carried out.
Another object of the invention is to provide a liquid laundry product which has improved stability while maintaining desired viscosity, performance, and soda ash loading.
A further object is to provide such surfactants, and detergents incorporating the same, which exhibit the detergency (cleaning) and esthetic (whiteness) characteristics required of commercial laundry detergents and which, moreover, have substantially improved sudsing characteristics.
It is a further object of the invention to provide a detergent which is more tolerant of high soda ash content, especially in liquid detergent formulations, than otherwise.
Yet another object of the invention is to provide a detergent formulation, especially a liquid detergent formulation, which has an increased soda ash content so as to permit a reduced surfactant content and thereby reduce overall detergent cost.
Still other objects of the invention will be recognized by those of ordinary skill in the art.
BRIEF SUMMARY OF THE INVENTION
These objects are surprisingly achieved by the utilization of a mixture of alkylaryl-O-ethoxylates and the corresponding sulfates thereof as the surfactant portion of a high soda ash content laundry detergent, especially a high soda ash liquid laundry detergent. The mixture of alkylaryl-O-ethoxylates (which is then partially sulfated) is of the formula:
C
6-12
alkyl-C
6-10
aryl-O—(CH
2
CH
2
O)
n
OH (I)
where there is at least one component where n is 1-6 (the low ethoxylate component) and at least one component where n is 7-12 (the high ethoxylate component). This mixture is then partially sulfated generally in the manner shown by Lengyel (except that there is no free alkylaryl-OH). The at least 4 part mixture (of the low ethoxylate component, the high ethoxylate component, and their respective sulfates) is then used in amounts of up to about 50% of the formulation of a laundry detergent, especially a liquid laundry detergent.
BRIEF DESCRIPTION OF THE DRAWING
Not Applicable
DETAILED DESCRIPTION OF THE INVENTION
Ethoxylated aryl alcohols which are partially sulfated in the practice of this invention have the formula
C
6-12
alkyl-C
6-10
aryl-O—(CH
2
CH
2
O)
n
OH (I).
The C
6-12
alkyl group is preferably selected from alkyl groups of 7-11 carbon atoms, more preferably 8-10 carbon atoms, and still more preferably is nonyl. It may be straight or branched, but straight chains are preferred. The C
6-10
aryl group is preferably phenyl or naphthyl, with phenyl being preferred. The number of ethoxy units (n) in the low ethoxy component is about 1 to about 6, preferably about 1.5 to about 5.5, more preferably about 2 to about 5, still more preferably about 3 to about 4, and most preferably about 4. The number of ethoxy units (n) in the high ethoxy component is about 7 to about 14, preferably about 8 to about 12, more preferably about 9 to about 10, and most preferably about 9. While the most preferable mixture to be used for partial sul
Carr Charles D.
Gupta Archana
Church & Dwight & Co., Inc.
Mruk Brian P.
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