Laundry detergent system

A laundry detergent system is described that comprises a chelating agent and ordinary soap. The chelating agent acts in the triple capacity of softening the water used for washing, buffering the wash water to a alkaline pH, and preventing soil redeposition.

RELATED PRIOR WORK 
This invention, in part, is similar in concept to a previous invention, U. 
S. patent application Ser. No. 08/274,426, filed Jul. 11, 1994 and to a 
co-pending application of even date herewith, entitled, "Shampoo 
Formulation". This invention relates to laundry detergents. 
BACKGROUND OF THE INVENTION 
RELATED PRIOR ART 
In this application I shall use the word "soap", or if there is possible 
ambiguity, "ordinary soap", to describe the salt of an alkali metal or 
amine and a fatty carboxylic acid. Prior to the 1950's most agents added 
to water for the washing of laundry were based upon ordinary soap. In the 
1950's major manufacturers throughout the world introduced detergent 
systems based upon synthetic detergents (syndets) for the washing of 
laundry. 
Shortly after their introduction, such systems came to dominate the market 
for laundry detergents. There were a number of reasons for this rapid 
acceptance. At the time alkylbenzene sulfonic acid (ABS) had been 
discovered. This material is outstanding as a detergent, when properly 
formulated, and, at the time, was both inexpensive, and environmentally 
acceptable. 
Later, in the 1960's, it was found that ABS is so persistent in the 
environment that it tended to cause streams and lakes to foam. This lack 
of biodegradability was identified as arising from the branched side alkyl 
chain of the ABS and was rectified (achievement of about 80% 
biodegradability) by using a liner alkyl side chain. Thus LAS, which 
stands for linear alkylbenzene sulfonic acid, replaced ABS. Detergents 
based upon this material dominate the world market at present. 
Laundry detergent systems are not just a detergent and water, however, and 
involve considerable subtlety in their formulation. Because it is hard to 
motivate the present invention without some discussion of these 
formulations, such systems are briefly described. 
LAS foams well and does not precipitate in hard water, however, it is not 
so effective a detergent as when used with soft water. The reason for this 
difference is that multivalent ions in the wash water adhere to and modify 
the surface charge of the clothes being washed so as to prevent proper 
lifting of soil from the fabric. 
LAS in soft water is effective at removing soil, but is not so effective at 
preventing redeposition. As a result additives that prevent such 
redeposition, in particular, carboxymethylcelluloses, are routinely added 
to detergent formulations. 
Many washing machines use aluminum components. Such components are 
chemically somewhat fragile, so that it is normal to add some sodium 
silicate to a laundry detergent system to prevent corrosion of the 
aluminum parts. The silicate, under the alkaline conditions of the wash 
water, forms an impervious coating of sodium aluminum silicate on the 
aluminum that prevents further attack. Currently plastic parts are being 
used more and more, however, so that, in time, it is anticipated that 
requirements for silicate will disappear. 
Finally it is generally true that LAS when combined with about twenty 
percent of its own weight of a nonionic surfactant becomes especially 
effective for cleaning. Though it is possible to base a detergent system 
on either a nonionic or LAS, this particular combination is more effective 
than either alone and costs less since less detergent is required. 
In summary, a detergent system ideally consists of a detergent combination, 
but mostly LAS, a water softener, usually a polyphosphate or zeolite in 
the United States, sodium silicate, carboxymethylcellulose, and a little 
perfume and perhaps some fluorescing dye (to dye the clothes whiter than 
white). Such systems may be supplemented by the inclusion of salts such as 
sodium sulfate to bulk out the detergent and to modify the ionic strength 
of the water in the wash. Such a modification is reputed to be helpful in 
the detergentcy of a system. 
Very recently it has become fashionable to reduce the amount of material 
that must be added to the washing machine to do a load of laundry. As a 
result laundry detergent systems have had to dispense with any extra 
material and present day detergents may have reduced levels of all but the 
most key ingredients. With present liquid systems, some detergents have 
eliminated the water softening agents altogether, probably to the 
detriment of the cleaning ability of the system. Presently about 60 grams 
of detergent are used per medium load of wash in the United States. 
Within the past two decades, it was found that by combining soaps with 
somewhat lesser amounts of certain detergents, which, when so used, are 
called lime soap dispersants, ordinary soap can be used in hard water. 
With most lime soap dispersants, the amount required depends on the 
hardness of the water and the amount of water used. In at least one case, 
that of certain sulfobetaines, the soap and lime soap dispersant need only 
be mixed in certain proportions and the combination is effective in almost 
any hardness at any dilution. This approach to using soaps is being used 
by some individuals at present, primarily for environmental reasons. 
In spite of extensive work with detergent systems over the past years, some 
defects remain. Generally present day detergents leave clothes with a 
harsh handle, that is, hard and boardy and with a coarse feel, and with 
considerable static cling. As a result materials have been developed that 
may be added to the wash or dryer that soften clothes and eliminate static 
cling. Generally the materials that perform this function are certain 
fatty quaternary amines that surface treat fabrics and impart a softer 
feel. They also give better static discharge characteristics. 
Over the years syndets have become relatively more expensive compared to 
soaps. The increase in cost of petroleum products compared to natural fats 
and oils, and the cost of the LAS as compared to ABS have caused this 
change. Syndets are only about 80% biodegradable and though such a level 
permits their use at present, future population growth may change the 
present picture in the United States. In some places, an example being 
Niagara Falls, present levels of stream contamination are giving problems 
with stream foaming. 
BRIEF SUMMARY OF THE INVENTION 
Most of the problems associated with present day use of detergents could be 
solved by switching the basic surfactant in the detergent from syndets to 
soap. Soaps do not give a harsh handle to fabrics and are essentially 
completely biodegradable. Such an idea may appear obvious, however, soaps 
suffer from two fundamental problems that inhibit their use at present and 
which were responsible for the switch to syndets in the first place. 
Soap precipitates in hard water. In such a situation soap not only loses 
any effectiveness as a cleaning agent, but becomes part of the problem. 
Soap precipitated by calcium, magnesium, or iron forms a sticky residue 
that itself is a soiling agent. Secondly, soap is subject to a decay in 
performance if it comes in contact with acids. Fatty acids themselves are 
weak and thus precipitate at a pH only slightly lower than neutral. 
This invention relates to a system that combines soap with certain 
chelating agents. Preferred realizations of this combination unexpectedly 
gives rise to a system that works well in soft and cold water, has good 
alkaline reserve to prevent sensitivity to acids, is near 98% 
biodegradable, prevents redeposition in the wash, leaves clothes with a 
soft handle, is very inexpensive and efficient and cleans better than 
conventional syndet based materials. Furthermore the system is less 
expensive than conventional detergents and uses less physical material to 
perform the function of washing. This latter fact, especially when 
combined with the information that the system is at least 98% 
biodegradable, attests to its environmental desirability. 
Specifically, the preferred implementation of this invention comprises a 
combination of trisodium nitrilotriacetic acid, ordinary soap, and, 
optionally, small amounts of sodium silicate, perfumes, colorants, 
fluorescing dyes, and so forth. Water soluble materials that bulk out the 
detergent system so that essentially more needs to be used, may, of course 
be added, provided enough material is used in each wash load to maintain 
the required level of essential ingredients. 
Surprisingly this combination of ingredients suffices for the achievement 
of the objectives sought with a good detergent system for laundry. 
Nitrilotriacetic acid (subsequently referred to as NTA) is not only an 
effective and powerful chelating agent so that it permits the use of soap 
in hard water, but, in addition, prevents the redeposition of soil onto 
clothes during the wash cycle. A detergent system based upon NTA and soap 
produces an extraordinarily clean wash. 
NTA's third acid group is a weak acid so that its third sodium ion is a 
effective buffer for the laundry pH. Thus the second vulnerability of 
soap, that is sensitivity to acids is overcome. 
Perhaps the most surprising finding associated with the use of NTA with 
soaps is that it permits tallow soap to be used in cold water. It is a 
given in the literature, and a finding in my laboratory, that tallow 
soaps, even when reduced to a flowable powder, do not adequately dissolve 
in cold water during a normal wash cycle. When sufficient NTA is included 
in the water to soften it completely, ie. better than a mole equivalent to 
the hardness in the water, the soap dissolves in only a few minutes of the 
wash cycle. The reason for this surprising result has not been determined. 
It is suspected that under conditions normally found with ordinary hard 
waters, enough insoluble soap forms on the surface of grains of soap so as 
to prevent ready dissolution of the soluble soap underneath. 
NTA is remarkably inexpensive. It may be produced from equimolar portions 
of ammonia, sodium cyanide and formaldehyde, with the latter two both 
being inexpensive feedstocks. Alternatively it may be produced from 
hydrocyanic acid and formaldehyde that is subsequently treated with sodium 
hydroxide. This latter route uses slightly lower cost feedstocks, and 
produces acleaner product. Ammonia is a byproduct of the manufacturing 
process and, of course, then need not be a feedstock. The molecular weight 
of trisodium NTA monohydrate is only about 275 Daltons and it is effective 
on an equimolar portion of hardness ion. It is thus unsurpassed in its 
weight effectiveness as a chelating agent. 
Based upon experience in Europe, most notably in Switzerland, NTA is about 
98% biodegradable. This attribute is not shared to the same extent by most 
other of the common chelating agents except for the polyphospahtes. 
In the United States NTA has been approved by the EPA for uses that include 
home laundry. Presently NTA, as mentioned above, is approved for use for 
the same purpose in Canada, Switzerland, the Netherlands and some other 
countries. It is to be expected that as time goes by the list of countries 
that approve the material for use in laundry will increase. 
Presently tallow soap is less expensive than LAS, and likely to grow even 
less expensive on a relative basis in the future. Furthermore, in the 
right environment, specifically in perfectly soft water, soap is more 
effective than LAS as a cleaning agent. Typical tallow soaps have average 
molecular weights of slightly less than 300, while LAS sodium salt is 
about 350. 
Finally soap imparts a soft handle to clothes wheras LAS gives a harsh 
feel. With the latter materials, fabric softeners are highly desirable, 
while with soaps they are seldom required. Fabric softeners are expensive. 
Soap, being the alkali metal salt of a natural fatty acid, is highly 
biodegradable. Whatever soap survives to the water treatment plant is 
immediately precipitated by any alum treatments to desludge the water. NTA 
has been extensively used with syndets in Canada and Switzerland. 
Extensive animal testing of the toxicity of NTA has shown no problem with 
the material. 
DETAILED DESCRIPTION OF THE INVENTION 
This invention comprises 5-80% of the alkali metal or amine salts of 
certain chelating agents, 20-95% of ordinary soap, and, optionally, 0-20% 
of an alkali metal salt of silicic acid. In addition to these ingredients, 
optionally, other minor ingredients such as perfumes, dyes, and bleaches 
may be added. It is also an option to add water soluble materials that 
dilute the more expensive main ingredients. Such materials might include, 
for example, more sodium silicate, sodium sulfate, sodium carbonate, 
borax, sodium chloride, various phosphates, and so forth. Generally 
speaking diluents serve to reduce the per pound cost, but add little to 
the cleaning power of the system so that more material must be used to 
wash a given amount of clothes. 
The purpose of any formula for doing laundry is, of course, to achieve 
certain levels of active ingredients in the bath that actually washes the 
clothes. As will be described in more detail below, it is essential to the 
function of this invention to chemically chelate all hardness in the water 
used for the laundry. This implies that enough chelating agent be present 
so that there is at least one molecule of such an agent for each molecule 
of hardness. 
Hardness levels range from a three parts per million in homes equipped with 
efficient water softeners to perhaps 350 ppm in desert regions of the 
world. Since the most efficient common chelating agent has a molecular 
weight of 275, about 275 ppm of chelator is required for 100 ppm of 
hardness, the range of required chelating agent might be from about 10 to 
1000 ppm. 
The amount of soap required in a laundry bath is somewhat subjective. In 
perfectly softened water, clothes are cleaned quite effectively with no 
soap in the bath. On the other hand the inclusion of soap leads to cleaner 
clothes, less sensitivity to impurities brought in with the bath, and to 
softer and better looking laundry. The amount does not appear to be very 
critical, but, in accord with time-honored practice, maximum cleaning 
seems to occur with light levels of foam in a soap system. I have found 
that a minimum level appears to be about 20 ppm while the upper level is 
not critical and can be as high as 3000 ppm. 
The natural soap portion includes the water soluble basic salts of various 
fatty carboxylic acids. By soluble is meant that at least 20 milligrams 
per liter of the particular soap must dissolve in water at room 
temperature. By fatty carboxylic acid is meant a carboxylic acid moiety 
connected with a relatively long aliphatic hydrocarbon chain. Such fatty 
acids for soaps, at least in the United States, are derived almost 
exclusively from natural sources and conventionally are saturated or 
unsaturated linear C6-C22 carbon chains with the acid group at the 
molecule end. An exception is rosin which has a relatively complex C20 
unsaturated acid as its main constituent. Another is the major fatty acid 
derived from castor oil that has a hydroxyl on its carbon chain, as well 
as an unsaturation. 
Generally the soaps useful for purposes of this invention include the 
soluble basic salts of C6-C22 linear fatty acids. The most common 
saturated fatty acids for soap are C12-C18 acids named, starting at twelve 
and going by even numbers to eighteen, lauric, myristic, palmitic, and 
stearic. The most common unsaturated acid is oleic which is a C18 fatty 
acid with a cis double bond in the ninth position. Oleic acid is the most 
widely distributed fatty acid in nature and is a major constituent of most 
animal or vegetable fats. The second most common unsaturated fatty acid is 
called linoleic acid and has two unconjugated double bonds, both in the 
cis configuration with one on the ninth and the other on the twelfth 
carbon. 
The least expensive fatty acids in the United States are those derived from 
animal sources, most usually beef and pork fat. The bulk of the actual 
fatty acids from these sources are oleic, palmitic, and stearic acids. 
These fatty acids are generally stable enough against oxidation so that 
they form stable soaps when neutralized. Other sources of fatty acids that 
are useful for purposes of this invention include palm oil, coconut oil, 
palm kernel oil, hydrogenated vegetable oils, vegetable oils, navel stores 
(tall oil products), castor oil, and other animal fats. 
The preferred fatty acids for purposes of this invention include those from 
tallow, grease, vegetable oils and navel stores. The most preferred fatty 
acids are those derived from tallow and grease because of their cost and 
availability. Such materials are generally limited to use in powdered 
formulations, however, since even their potassium salts are too insoluble 
in water to permit a liquid formulation. 
In the case of liquid systems, materials such as rosin, liquid vegetable 
oils, and coconut or palm kernel oil fatty acids are most useful. Of these 
the most preferred are the short chain saturated fatty acids from coconut 
and palm kernel oils because of their stability against oxidation. 
Unsaturated oils may be used, of course, but a formulation must contain a 
portion of some antioxidant such as, for example, a hindered phenol, in 
order to prevent the development of rancidity. There are many agents that 
may be used as anti-oxidants, and such agents are readily available 
commercially. A good reference is Kirk-Othmer, Encyclopedia of Chemical 
Technology, 3rd Edition (John Wiley & Sons, New York, N.Y.), Vol. 3, pp. 
128. 
The base used to form the soap of this invention can include the alkali 
metals and various amines. Traditionally, soaps have been formed from the 
alkali metal salts of fatty acids, specifically the sodium and potassium 
salts. The latter are much more soluble than the former in water. 
In laundry detergents formulated as dry powders the sodium salt is 
preferred because of its physical hardness, low cost and stability. In the 
case of liquid formulations, the potassium salt is usually required to 
achieve enough water solubility to permit use of reasonable amounts of 
soap and chelating agent in a water based liquid. For use with ordinary 
laundry, the alkali metal salts are most preferred, however, special soaps 
must be used with woolens, silks and other fine fabrics that are alkali 
sensitive. 
Alkali metal salts, in the case of near complete neutralization of the 
fatty acid, are quite basic, since the fatty acid is relatively weak and 
the base quite strong. To overcome this problem without, at the same time, 
decreasing the stability and effectiveness of the soap, the potassium and 
sodium salts may be combined with weak amine salts to produce a system 
with both reasonable stability and relatively low pH. Such soaps are 
suitable for wool or silk. 
In such cases generally the alkali metal salt constitutes greater than 80% 
of the soap, but the rest is a weak amine salt. It also is generally 
desirable to provide for an excess of the amine salt over stoichiometry to 
both act as a buffer for the system and maintain the pH at an optimum 
level. 
By weak amine salts are meant various ammonium compounds. Ammonia itself 
suffers not only from the fact that it is volatile, so that its presence 
in the system may be somewhat transient, but also is highly odoriferous, 
so as to detract from the system's esthetic value. Ordinary aliphatic or 
aromatic hydrocarbon amines tend to be both odorous and toxic, and thus 
are not preferred. Amino alcohols, and alkanolamines as described, for 
example in Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Edition 
(John Wiley and Sons, New York, N.Y., 1978) Vol. 1, pp 944, are the 
preferred materials for this invention. The most preferred amines are 
triethanolamine and triisopropanolamine. 
Chelating agents that may be used with this invention are materials that 
act to powerfully prevent precipitation of the insoluble salts of 
polyvalent ions, found in normal hard water, with fatty acids. Though 
there are many such agents inclusive of zeolites, hydroxy acetic acids, 
and so forth, the most effective agents are the polyphosphoric acids, the 
amine or polyamine polyacetic acids, and the amine or polyamine 
polymethylenephosphonic acids. 
Polyphosphoric acids are derived by heating the acid salts of phosphoric 
acid. In particular the monobasic sodium salt of orthophosphoric acid may 
be heated to form a glass that is highly soluble in water. Such a 
polyphosphate is variously called sodium polyphosphate or sodium 
hexametaphosphate. Other sodium polyphosphates are derived from 
combinations of monobasic and dibasic sodium phosphates that are heated in 
various ways. Potassium polyphosphates are manufactured by heating certain 
potassium acid salts of phosphoric acid. These materials are powerful 
chelating agents; however, they suffer from the fact that phosphates in 
general, are fertilizers, that is, nutrients for plant growth. 
In the environment phosphates that were released, in part from household 
laundry products, led to the uncontrolled growth of algae in various lakes 
and streams in the United States. As a result phosphates have been banned 
by various government agencies. In addition they are no longer fashionable 
and are difficult to sell as part of a laundry product, at least in the 
United States. In addition phosphates are moderately expensive considering 
their effectiveness. Finally phosphates are not hydrolytically stable, 
especially in strongly alkaline, hot aqueous environments, such as may be 
found in a laundry tub. For these reasons polyphosphates are not preferred 
for purposes of this invention. 
There is a series of compounds derived from the reaction of an amine or 
polyamine with formaldehyde and phosphoric acid. Ammonia, for example, 
when so reacted forms nitrilotrimethylenephosphonic acid. Such a material 
when properly neutralized (ie. pH 10, for example) is useful for purposes 
of this invention. Similar compounds derived from ethylenediamine, 
hydroxyethylethylenediamine and so forth, again reacted with formaldehyde 
and phosphoric acid, are all useful. Such materials tend to be more 
expensive than more common agents, and, though effective and available, 
are not widely used, at least in soaps or cosmetics. These compounds are 
stable against hydrolysis. 
These agents, the polyaminepolymethylenephosphonic acids are somewhat 
expensive and do not really solve the problem of the prejudice against 
phosphate use in laundry detergent systems. Because of their cost, such 
compounds have been restricted to uses that take advantage of their 
unusual ability to prevent crystal growth at very low concentrations. 
These materials are not preferred for purposes of this invention. 
There are a series of materials formed from the reaction of an amine or 
polyamine with formaldehyde and sodium cyanide. Such materials presently 
are made by either of two procedures. In one of these methods an alkali 
cyanide is reacted with formaldehyde and a polyamine, such as, for 
example, ethylenediamine. The alkali metal salt of, in this case, 
ethylenediaminetetraacetic acid is formed directly along with ammonia. 
In the second procedure hydrogen cyanide is reacted directly with 
formaldehyde in acid solution in the presence of the desired amine and the 
cyano compound is formed. This latter material is not soluble and can be 
easily separated from the reaction mix, and, incidentally, purified. The 
cyano compound is then hydrolyzed to the acetic acid compound with the 
release of ammonia by interaction with the appropriate alkali metal 
hydroxide. Since this route yields a purer product and has slightly less 
expensive feedstocks, it is preferred, at least when made in a properly 
equipped plant. 
Many amines can be used for this reaction. In the United States materials 
made from ethylenediamine, from diethylenetriamine, and ammonia are all 
available commercially. Of these, the material made from ammonia is called 
nitrilotriacetic acid and is both highly effective, when used with soap, 
and low-cost. Because NTA has the lowest molecular weight of the 
polyaminepolyacetic acids, it is the most effective on a pound-for-pound 
basis. The feedstock for NTA uses only cyanide, alkali, and formaldehyde, 
since (as mentioned above) ammonia is generated from the reaction. 
Surprisingly, when NTA is used in a detergent system based upon soap, the 
NTA acts upon released dirt to prevent redeposition of the dirt upon the 
clothes. Though not all alternatives of the polyaminepolyacetic class of 
chelating agents have been tested, NTA appears to be singularly effective 
in this regard. In general, the polyaminepolyacetic acids are the 
preferred chelating agents for purposes of this invention. Of these 
materials NTA is the most preferred because of its cost, effectiveness, 
and action to prevent redeposition. 
About twenty years ago NTA, was proposed as a chelating agent to be used 
with syndet-based laundry detergents. Some initial toxicity testing 
regarding certain toxic metal chelates of NTA seemed to point to health 
problems with the material. Since that time extensive studies have shown 
no problem with the product and it currently is used in Switzerland, 
Holland, and Canada in syndet-based laundry detergent systems. Presently 
NTA has been approved for use in the United States for laundry detergents. 
When used in formulations that come under various Federal and State 
labeling and right to know laws, NTA must be identified in the product, 
and appropriate warnings given. 
The level of chelating agent required in a laundry detergent relates to the 
level of hardness expected in water, the amount of detergent used with a 
load of laundry, and the molecular structure of the chelating agent 
involved. In the United States, average water hardness is only the 
equivalent of 90 parts per million of calcium carbonate. Eighty percent of 
all U.S. water supplies have hardness of less than 150 parts per million. 
In the U.S. an average washing machine has a capacity for a medium load of 
about fifty liters of water. The required amount of trisodium NTA 
monohydrate (the form available commercially) to chemically soften water 
of 150 parts per million of equivalent calcium carbonate average hardness 
is about 21 grams. 
In Europe hardness levels are closer to two hundred. In Japan levels of 
hardness average only 25 parts per million. In Europe washing machines 
have washing chambers that are smaller than the U.S. (front loading 
designs) so that detergent systems need actually have less chelating agent 
per wash since less water is softened is spite of the fact that the water 
is generally harder. In Japan, washers are more like those in the U.S. but 
generally physically smaller. In Europe, similar formulations to the U.S. 
are effective. In Japan relatively less NTA per load is required so that 
the proportion of NTA in a detergent system might be cut by a factor of 
three. 
Only about two thirds of the weight of NTA compared to EDTA is required to 
deal with the same level of hardness. With sodium tripolyphosphates, 
comparable levels to EDTA are desirable. In the case of tetrapotassium 
pyrophosphate almost three times as much material is required as with 
trisodium NTA monohydrate. 
I have found that in truly soft water such as is achieved with one mole 
equivalent of NTA, remarkably little tallow soap is required to clean 
clothes, typically only about 100 parts per million. In the case of an 
average washing machine in the U.S. such a level corresponds to only about 
five grams per medium load. 
A typical formulation suitable for the U.S. and Europe, neglecting any 
perfumes and such, might have 21 grams of trisodium NTA, monohydrate, 
seven grams of tallow soap powder, and one third gram of sodium silicate. 
Two tablespoons full containing about one ounce by weight would suffice 
for a medium load of laundry in the U.S. This level is half that of the 
most concentrated present day laundry powders based upon syndets. Since 
this level suffices for 150 ppm hardness, less hard water could use even 
less of this powder and achieve satisfactory performance. 
In Europe, with front loading, lower water capacity washers, but harder 
water about the same use per wash might suffice. In Japan the ratio of 
trisodium NTA monohydrate to soap might best be changed to about one to 
one and only about one half to two thirds a tablespoon should be more than 
adequate per load of laundry.

The teachings of this invention may be illustrated through the following 
examples. 
EXAMPLE 1 
Lux brand bar bath soap was purchased from Kroger Grocery in Dayton, Ohio, 
and was grated using the fine side of an ordinary kitchen grater to give 
one pound of soap powder. This powder was mixed with 772 grams of 
"Hampshire NTANa3" trisodium NTA, monohydrate, from Hampshire Chemical 
Corp., of Lexington, Mass. The resulting white powder was tested by 
putting one level tablespoon of the mixture in a General Electric home 
washer set on ordinary cycle, cold wash and cold rinse, and extra large 
load. The tablespoon measured 14 grams by weight. The input water to the 
washer was softened Dayton, Ohio, water. The washing machine was activated 
and the water tested at intervals of one minute. After three minutes no 
particles of soap could be detected in the wash water and the wash water 
was completely transparent. This transparency was taken to mean that the 
water was completely soft. Otherwise the water would have been cloudy from 
precipitated soap particles. The action of the washer produced moderate 
foam in the machine (about two inches high). 
EXAMPLE 2 
One tablespoon of the soap prepared in Example 1 was again added to the 
washing machine of example 1 using the same washer settings. This time, 
however, the machine was run with a full load of ordinary household 
laundry. Only light foaming was noted during the wash cycle. After washing 
and drying, using no bleach or softeners, the clothes were examined and 
found to be soft and clean and easily folded. No static cling was noted 
with fabrics normally subject to the problem. 
EXAMPLE 3 
A clean white 100% cotton twin bed sheet was purchased from J. C. Penney in 
Dayton, Ohio, and washed twice using Tide detergent from Procter &. Gamble 
Company of Cincinnati, Ohio. The sheet was then dried. The sheet was cut 
in half and each half given an identifying mark. Each half was washed in a 
standard General Electric washing machine using normal cycle, cold wash 
and rinse water, and medium load in wash water to which 10 grams of Elftex 
8 carbon black powder from Cabot Chemical Company of Boston, Mass., had 
been added. During the washing one of the half sheets had Tide detergent 
from Procter & Gamble added in accord with directions on the package. The 
other half used two tablespoons of the detergent system prepared in 
Example 1. After washing, it was found the Tide washed material lost 17.1 
units of brightness as measured by a standard Launderometer while the half 
washed with the material prepared in Example 1 had a brightness loss of 
10.6 units. The difference in color of the two sheets could easily be 
detected by eye. This result is taken as indicative that redeposition of 
soil is more than adequately prevented by the detergent systems of this 
invention. 
EXAMPLE 4 
The experiment of Example 3 was repeated using yet a third half sheet 
similarly prepared. In this experiment, however, 7 grams of soap powder, 
and 21 grams of tetrasodium EDTA from Aldrich Chemical Company of 
Milwaukee, Wis., was used as the detergent system. In this instance, the 
brightness units lost were 15.2, which was taken to indicate the 
redeposition of the trisodium NTA, was superior to that of EDTA. 
EXAMPLE 5 
One kilogram of Anar Chemical Co.,(of Addison, Ill.) Anar 45 soap powder 
was mixed with three kilograms of Hampshire NTANa3. This mixture was 
furnished to Patterson Park Laundromat of Dayton, Ohio for trial. 
Ordinarily Patterson Park Laundromat does about 50 loads of wash per day 
on a full service basis, that is, the employees of the laundromat wash and 
dry the clothes for customers and return the completed folded laundry to 
them. The trial was run for two days. The company reported that they could 
obtain clothes whiter than normal with no use of bleach. Furthermore no 
softening agents at all were required with the clothes and it was reported 
that they folded better than normal. On this basis the laundromat made 
plans to convert completely to the new system, requesting only that some 
scent be added to make the laundromat have a pleasent odor.