Drycleaning detergent solution

The detergent action and antiredeposition properties of a drycleaning solvent containing sodium petroleum sulfonate are improved by the addition of a small amount of high molecular weight polyglycol. Perchloroethylene solutions of the anionic detergent and polyglycols of 15,000 and 50,000 molecular weight made from mixed ethylene and propylene oxides are specifically disclosed.

BACKGROUND OF THE INVENTION 
The present invention relates to drycleaning solvent compositions having 
improved detergent activity and antiredeposition properties. More 
particularly, it relates to drycleaning solvent solutions containing an 
anionic detergent and a polyglycol additive. 
It is well known that the cleaning properties of a drycleaning solvent are 
enhanced by the presence of a dissolved soap or synthetic detergent. It is 
also known that these properties are further improved by the addition of a 
small amount of a low molecular weight polyol to such a solution. Edwards, 
U.S. Pat. No. 3,091,508 describes drycleaning solvent compositions 
containing detergent esters and polyglycols with molecular weights in the 
range of 200-1000. Barnes, U.S. Pat. No. 3,222,286 discloses somewhat 
similar drycleaning solvent compositions containing an arylsulfonate and a 
polyglycol ether of about the same range of molecular weight. 
SUMMARY OF THE INVENTION 
It has now been found that for solutions of certain anionic detergents in 
drycleaning solvents, the addition of a small amount of a polyglycol 
having a very high molecular weight in the range of about 10,000-100,000 
not only markedly improves the detergency of the solutions as compared to 
the effect of polyglycols of lower molecular weight, but also adds 
excellent antiredeposition properties not shown by somewhat similar prior 
art compositions. The anionic detergents are generally described as alkali 
metal long chain alkyl aromatic sulfonates, particularly those known as 
petroleum sulfonates, sometimes called mahogany sulfonates, which are 
essentially alkylbenzenesulfonates where the alkyl group contains about 
16-24 carbon atoms and where the term alkali metal includes any of that 
group plus ammonium. Specifically, the improved drycleaning composition 
consists essentially of a drycleaning solvent containing about 0.1-4 
percent by weight of petroleum sulfonate, preferably the sodium salt, and 
about 0.01-0.4 percent of a polyoxyalkylene glycol of average molecular 
weight in the described range, and preferably in the range of about 
12,000-60,000, wherein the oxyalkylene groups are mixed oxyethylene and 
oxypropylene groups.

DETAILED DESCRIPTION 
While any drycleaning solvent can be used, that is, hydrocarbons such as 
naphtha or Stoddard's Solvent and halogenated lower aliphatic hydrocarbons 
such as carbon tetrachloride, perchloroethylene, 
tetrachlorodifluoroethane, and trichloroethylene, the halogenated 
hydrocarbons are preferred and perchloroethylene is most preferred. The 
term "halogenated lower aliphatic hydrocarbon" is used herein to mean 
hydrocarbons of 1-3 carbon atoms having one or more fluorine and/or 
chlorine substituents. 
The preferred concentration of sulfonate detergent is about 0.5-2 percent 
by weight of solvent with the concentration of polyglycol about one-tenth 
of that amount. These proportions can be varied within the general limits 
cited for particular cleaning problems. 
The mixed ethylene-propylene polyglycol component can be either a block or 
random copolymer, ordinarily using an appropriate glycol, polyglycol, or 
other polyol starter. Water could be used as the starter, but it is 
usually less convenient. Mixed polyglycols of about 5-95 mole percent 
oxyethylene units and 95-5 mole percent oxypropylene units are preferred 
and most preferably a polyglycol containing about 50-90 mole percent of 
oxyethylene units is used. As disclosed above, such polyglycols of about 
10,000 to about 100,000 average molecular weight are useful in the 
invention and a polyglycol having an average molecular weight of about 
12,000-60,000 is preferred. The conventionally used weight average 
molecular weight as determined by viscosity measurement is referred to 
herein. 
TEST PROCEDURE 
A 600-ml portion of a solution of sodium petroleum sulfonate (Penreco 
Petrosul 744-LC) and high molecular weight polyglycol in perchloroethylene 
was put in a Terg-o-tometer test beaker having a stirring spindle which 
rotated at 100 rpm. A quantity of 0.4 g. 200 mesh vacuum soil was 
dispersed in the solution. For antiredeposition testing, five test 
swatches 2 .times. 3 inches in size of cotton print cloth, wool gabardine, 
100 percent polyester, and a 65 percent polyester-35 percent cotton 
permanent press blend were put in the solution, also a standard carbon 
soil swatch (4 .times. 4-inch wool -- Foster D. Snell artificially soiled) 
for carbon soil removal determination. After agitation for 20 minutes, the 
swatches were removed from the solution, air-dried, and the reflectance of 
each dry swatch was measured using a photometer with a green Tristimulus 
filter and compared to that of the corresponding blank swatch. Results are 
listed as percentages of the blank reading, taken as 100 percent. 
EXAMPLES 1-2 
Solutions of sodium petroleum sulfonate (744-LC) and high molecular weight 
polyglycol in perchloroethylene were made up in the following proportions: 
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Solution 1 
Na petroleum sulfonate 0.9 g. 
Polyglycol A* 0.1 g. 
perchloroethylene 100 g. 
Solution 2 
Na petroleum sulfonate 0.9 g. 
Polyglycol B** 0.1 g. 
perchloroethylene 100 g. 
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*Polyglycol A - 85:15 mole ratio ethylene oxide:propylene oxide mixture 
condensed with propylene glycol, molecular weight (average) 50,000. 
**Polyglycol B - similar to A but a 75:25 mole ratio of ethylene oxide to 
propylene oxide, average molecular weight about 15,000. 
These solutions were tested for carbon soil removal and antiredeposition 
properties using the test procedure outlined above. A solution of 1 
percent sodium petroleum sulfonate in perchloroethylene with no polyglycol 
additive was tested in the same way for purpose of comparison. The results 
listed in Table I are averages for the swatches run. 
TABLE I 
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Poly- Antiredeposition Carbon 
Example 
glycol 65/35 Poly- Soil 
No. Additive Wool Cotton 
P.P. ester Removal 
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blank none 79.0 88.0 87.0 69.0 14.0 
1 A 96.0 93.5 97.5 90.0 60.0 
2 B 93.0 96.0 97.5 88.0 41.0 
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EXAMPLE 3 
A Polyglycol A-sodium petroleum sulfonate solution made up as in Example 1 
was compared to solutions made up in the same proportions using 
polyethylene glycol, molecular weight 400 (E-400) and polypropylene 
glycol, molecular weight 400 (P-400) respectively as the polyglycol 
additives. A blank sulfonate-perchloroethylene solution was also tested. 
The test procedure was as described above except that 0.3 g of vacuum soil 
in 600 ml of solution was used instead of the 0.4 g used previously. These 
results are listed in Table II. 
TABLE II 
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Antiredeposition Carbon 
Polyglycol 65/35 Soil 
Additive Wool Cotton P.P. Polyester 
Removal 
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none 96.0 97.5 96.0 86.5 24 
A 97.0 97.5 99.0 91.5 48 
E-400 93.5 81.0 94.0 82.0 42 
P-400 89.0 90.5 93.5 80.0 41 
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Comparable antiredeposition and carbon soil removal results are obtained 
when the high molecular weight polyglycols used in Examples 1-3 are 
replaced by similar quantities of other polyglycols within the molecular 
weight and chemical structure limits defined for this invention. For 
example, a 50:50 ethylene oxide-propylene oxide polyglycol of 25,000 
molecular weight, a 60:40 ethylene oxide-propylene oxide polyglycol of 
75,000 molecular weight, and a 25:75 ethylene oxide-propylene oxide 
copolymer of about 20,000 molecular weight all give results similar to 
those shown above when substituted for the polyglycol component of 
Solution 1 or Solution 2.