Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
2001-11-15
2003-06-10
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S123000, C510S126000, C510S127000, C510S158000, C510S218000, C510S426000, C510S427000, C510S470000, C510S490000, C510S492000, C510S536000
Reexamination Certificate
active
06576603
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
The present invention generally relates to a process for making low viscosity ether sulfates. More particularly, the viscosity of ether sulfates can be lowered by forming nematic liquid crystals in concentrated ether sulfate systems with the use of alkyl polyglycosides.
It is known that various surfactants have been found to be useful in cleaning compositions, such as shower gels, shampoos, and light duty detergents such as dishwashing detergents. In these types of compositions, good foamability is a prerequisite. The most widely used surfactants in these types of compositions are anionic surfactants such as alkyl sulfates, alkyl ether sulfates, sulfonates, sulfosuccinates and sarcosinates.
Mixtures of surfactants are prepared and sold for a wide variety of industrial and domestic applications. They are often required in a fluid form, and it is desirable that they should contain as high a proportion of active material as possible.
Ether sulfates are commonly used in HDL and LDL detergent formulations. These compounds have a tendency to form viscous gels in concentrated solutions. Consequently, hydrotropes such as ethanol and sodium xylene sulfonate are commonly added to the concentrated solution in order to reduce the viscosity of the ether sulfate solutions, thereby preventing subsequent gel phase formation. The high viscosity in concentrated systems containing ether sulfates is believed to be due to the formation of hexagonal and lamellar liquid crystal phases in the system.
While the use of non-surface active hydrotropes to reduce the viscosity of concentrated ether sulfate systems has proven to be fairly effective, it would be much more desirable to avoid the addition of any non-surface active, volatile organic compounds and, instead, employ surface-active, VOC-free compounds to achieve the same viscosity-reducing affect.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to a concentrated surfactant composition having nematic liquid crystal phases, the composition containing:
(a) from about 30 to about 70% by weight of an alkyl ether sulfate;
(b) from about 0.1 to about 10% by weight of an alkyl polyglycoside corresponding to formula I:
R
1
O(R
2
O)
b
(Z)
a
(I)
wherein R
1
is a monovalent organic radical having from about 6 to about 30 carbon atoms; R
2
is a divalent alkylene radical having from 2 to 4 carbon atoms; Z is a saccharide residue having 5 or 6 carbon atoms; b is a number having a value from 0 to about 12; a is a number having a value from 1 to about 6;
(c) from about 0.1 to about 10% by weight of a salt; and
(d) remainder, water, all weights being based on the total weight of the composition.
The present invention is also directed to a process for reducing the viscosity of an alkyl ether sulfate concentrate which does not require the use of a non-surface active hydrotrope and/or volatile organic compound, involving:
(a) providing from about 30 to about 70% by weight of an alkyl ether sulfate;
(b) providing from about 0.1 to about 10% by weight of an alkyl polyglycoside of formula I:
R
1
O(R
2
O)
b
(Z)
a
I
wherein R
1
is a monovalent organic radical having from about 6 to about 30 carbon atoms; R
2
is a divalent alkylene radical having from 2 to 4 carbon atoms; Z is a saccharide residue having 5 or 6 carbon atoms; b is a number having a value from 0 to about 12; a is a number having a value from 1 to about 6; and
(c) providing from about 0.1 to about 10% by weight of a salt; and
(d) combining (a)-(c) to form a concentrated alkyl ether sulfate composition having nematic liquid crystal phases and a viscosity, at room temperature, of from about 4,000 to about 10,000 cps.
DETAILED DESCRIPTION OF THE INVENTION
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as being modified in all instances by the term “about”.
Alkyl ether sulfates are generally defined as salts of sulfated adducts of ethylene oxide with fatty alcohols containing from about 8 to about 16 carbon atoms. The alkyl ether sulfates employed in the present invention are commercially available and contain a linear aliphatic group having from about 8 to about 16 carbon atoms, and preferably from about 12 to about 16 carbon atoms. The degree of ethoxylation is from 1 to about 10 moles of ethylene oxide, and preferably about 2 to 3 moles of ethylene oxide. A particularly preferred alkyl ether sulfate for use in the present invention is C
12-16
ether sulfate having 2 moles of ethylene oxide, commercially available under the tradename TEXAPON® NC-70.
The alkyl polyglycosides which can be used in the present invention are those corresponding to formula I:
R
1
O(R
2
O)
b
(Z)
a
(I)
wherein R
1
is a monovalent organic radical having from about 6 to about 30 carbon atoms; R
2
is a divalent alkylene radical having from 2 to 4 carbon atoms; Z is a saccharide residue having 5 or 6 carbon atoms; b is a number having a value from 0 to about 12; a is a number having a value from 1 to about 6. Preferred alkyl polyglycosides which can be used in the compositions according to the invention have the formula I wherein Z is a glucose residue and b is zero. Such alkyl polyglycosides are commercially available, for example, as APG®, GLUCOPON®, or PLANTAREN® surfactants from Henkel Corporation, Ambler, Pa., 19002. Examples of such surfactants include but are not limited to:
1. GLUCOPON® 220 UP Surfactant—an alkyl polyglycoside in which the alkyl group contains 8 to 10 carbon atoms and having an average degree of polymerization of 1.5.
2. GLUCOPON® 425 Surfactant—an alkyl polyglycoside in which the alkyl group contains 8 to 16 carbon atoms and having an average degree of polymerization of 1.6.
3. GLUCOPON® 625 Surfactant—an alkyl polyglycoside in which the alkyl group contains 12 to 16 carbon atoms and having an average degree of polymerization of 1.6.
4. APG® 325 Surfactant—an alkyl polyglycoside in which the alkyl group contains 9 to 11 carbon atoms and having an average degree of polymerization of 1.6.
5. GLUCOPON® 600 Surfactant—an alkyl polyglycoside in which the alkyl group contains 12 to 16 carbon atoms and having an average degree of polymerization of 1.4.
6. PLANTAREN® 2000 Surfactant—a C
8-16
alkyl polyglycoside in which the alkyl group contains 8 to 16 carbon atoms and having an average degree of polymerization of 1.4.
7. PLANTAREN® 1300 Surfactant—a C
12-16
alkyl polyglycoside in which the alkyl group contains 12 to 16 carbon atoms and having an average degree of polymerization of 1.6.
Other examples include alkyl polyglycoside surfactant compositions which are comprised of mixtures of compounds of formula I wherein Z represents a moiety derived from a reducing saccharide containing 5 or 6 carbon atoms; a is a number having a value from 1 to about 6; b is zero; and R
1
is an alkyl radical having from 8 to 20 carbon atoms. The compositions are characterized in that they have increased surfactant properties and an HLB in the range of about 10 to about 16 and a non-Flory distribution of glycosides, which is comprised of a mixture of an alkyl monoglycoside and a mixture of alkyl polyglycosides having varying degrees of polymerization of 2 and higher in progressively decreasing amounts, in which the amount by weight of polyglycoside having a degree of polymerization of 2, or mixtures thereof with the polyglycoside having a degree of polymerization of 3, predominate in relation to the amount of monoglycoside, said composition having an average degree of polymerization of about 1.8 to about 3. Such compositions, also known as peaked alkyl polyglycosides, can be prepared by separation of the monoglycoside from the original reaction mixture of alkyl monoglycoside and alkyl polyglycosides after removal of the alcohol. This separation may be carried out by molecular distillation and normally results in the removal of about 70-95%
Haas Christina M.
Hessel John F.
Smith George A.
Cognis Corporation
Drach John E.
Ogden Necholus
Trzaska Steven J.
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