Dry, granular, bleaching compositions comprising an effective amount of diperoxydodecanedioic acid and sufficient buffering agent to control the pH of the aqueous solution in which the bleach is used in the range of 8.7 to 9.5. The peroxyacid and the buffering agent being present as separate granules in such compositions. Methods of using the compositions are also provided.

BACKGROUND OF THE INVENTION 
The present invention relates to a dry, granular, bleaching composition 
comprising a peroxyacid compound, diperoxydodecanedioic acid, and 
sufficient buffering agent to control the pH of an aqueous oslution of the 
bleach in the range of 8.7 to 9.5. 
Peroxygen bleaching agents in general and peroxyacid compounds in 
particular have long been recognized as effective bleaching agents for use 
when the adverse color effects of harsh active bleaching agents cannot be 
tolerated. See, for example, Canadian Pat. No. 635,620, Jan. 30, 1962, to 
McCune. The peroxyacids used have included aliphatic acids as disclosed in 
McCune, as well as aromatic acids such as diperoxyisophthalic acid 
disclosed in U.S. Pat. No. 3,770,816, Nov. 6, 1973, to Nielsen. Use of 
these agents has necessitated finding adequate solutions to a number of 
problems. Included in the types of problems heretofore recognized with 
peroxyacids are the tendency of such materials to undergo exothermic 
decomposition, the loss of available oxygen from peroxyacids as the result 
of contact with moisture and heavy metals and the degradation of 
peroxyacids as the result of contact with alkaline agents. 
It has also been discovered that, although diperoxyacids in general are 
milder to fabrics than chlorine-containing bleaches, they are not entirely 
free of fabric damage problems. The recognition of certain pinpoint color 
damage problems with peroxyacids in general is disclosed in Belgium Pat. 
No. 814,938, Nov. 13, 1974, to Gougeon et al. With the peroxyacid of 
interest of the present invention, diperoxydodecanedioic acid, nylon color 
damage can be fairly severe. This damage is due to the bleach active being 
adsorbed/absorbed onto/into the nylon fiber. 
The present inventor has discovered that the above-mentioned nylon color 
damage can surprisingly be reduced by maintaining the pH of the wash 
solution in which the bleach is used within a certain high pH range, 8.7 
to 9.5. It is theorized, although such theory is not to be considered 
binding, that at the pH's of the present invention the diperoxyacid is 
more completely ionized and the peroxyacid anion is much less substantive 
to the nylon fiber. The aforementioned Belgium patent does not suggest 
that optimized performance (low nylon color damage with high bleach 
effectiveness) of diperoxydodecanedioic acid would occur in the pH range 
given above. 
Accordingly, it is an object of the present invention to provide an 
improved fabric bleaching composition having superior bleaching 
performance. 
It is a further object of the present invention to provide a superior 
method of bleaching fabrics. 
These and other objects will become apparent from the description which 
follows. 
As used herein, all percentages and ratios are by weight unless otherwise 
specified. 
SUMMARY OF THE INVENTION 
The present invention encompasses a dry, granular composition comprising a 
peroxyacid compound in the form of diperoxydodecanedioic acid and 
sufficient buffering agent to control the pH of the water in which the 
bleach composition is used within the range of about 8.7 to about 9.5. The 
diperoxyacid and the buffering agent are present as separate granules in 
the composition. The present invention further encompasses a method of 
bleaching fabrics with the above composition. 
DETAILED DESCRIPTION OF THE INVENTION 
The two essential components of the compositions of the present invention 
are described below. 
PEROXYACID BLEACHING COMPONENT 
The bleaching agent of the present invention's compositions is 
diperoxydodecanedioic acid. This acid has the formula 
##STR1## 
Diperoxydodecanedioic acid is a solid having a solubility in 25.degree. C. 
water of about 0.1 gram/liter and a decomposition temperature of about 
101.degree. C. 
Peroxyacids, including the acid of the present invention, can be made in a 
variety of ways. A common way is to react the parent acid with hydrogen 
peroxide in the presence of sulfuric acid. Such a method is described in 
U.S. Pat. No. 2,813,896, Nov. 19, 1957, to Krimm, incorporated herein by 
reference. An additional method using the same reactants is described in 
Parker et al., "Peroxides. IV. Aliphatic Diperacids," Journal American 
Chemical Society, 79, pp. 1929-1931, (1957). This reference is also 
incorporated herein by reference. 
The compositions of the present invention contain an amount of the 
peroxyacid compound to provide adequate bleaching. This amount is 
generally between about 1% and 60% of the total composition and preferably 
from about 5% to about 30%. 
BUFFERING AGENT 
The second essential component of the compositions of the present invention 
is a buffering agent. As indicated earlier, the present compositions 
contain sufficient buffering agent to maintain the pH of the water in 
which the bleach is used within the range of about 8.7 to 9.5, preferably 
8.8 to 9.2. To maintain this controlled pH in solution, any noninterfering 
compound which can alter and maintain pH, such as any standard buffering 
agent or combination, is employed. For example, alkali metal carbonates, 
bicarbonates, phosphates, pyrophosphates, borates, silicates and mixtures 
thereof, which buffer within the range of 8.7 to 9.5. Examples of suitable 
buffering agents include sodium carbonate, sodium borate decahydrate, 
sodium phosphate and sodium pyrophosphate. Other buffering compositions 
for any desired pH can be obtained by the skilled artisan from any 
standard chemistry handbook or text book. 
The amount of buffering agent to provide the pH indicated above is 
generally from about 2% to about 90% of the total composition, preferably 
from about 5% to about 30%. 
OPTIONAL COMPONENTS 
It is well documented in the peroxyacid literature, as noted above, that 
peroxyacids are susceptible to a number of different stability problems, 
as well as being likely to cause some problems. Looking at the latter 
first, peroxyacids decompose exothermally and when the material is in dry 
granular form the heat generated must be controlled to make the product 
safe. The best exotherm control agents are those which are capable of 
liberating water at a temperature slightly below the decomposition 
temperature of the peroxyacid employed. U.S. Pat. No. 3,770,816, Nov. 6, 
1973, to Nielsen, incorporated herein by reference, discloses a wide 
variety of hydrated materials which can serve as suitable exotherm control 
agents. Included among such materials are magnesium sulfate 
.multidot.7H.sub.2 O, magnesium formate dihydrate, calcium sulfate 
(CaSo.sub.4 .multidot.2H.sub.2 O), calcium lactate hydrate, calcium sodium 
sulfate (CaSo.sub.4 .multidot.2Na.sub.2 SO.sub.4 .multidot.2H.sub.2 O), 
and hydrated forms of such things as sodium aluminum sulfate, potassium 
aluminum sulfate, ammonium aluminum sulfate and aluminum sulfate. 
Preferred hydrates are the alkali metal aluminum sulfates, particularly 
preferred is potassium aluminum sulfate. Other preferred exotherm control 
agents are those materials which lose water as the result of chemical 
decomposition such as boric acid, malic acid and maleic acid. The most 
preferred agent is boric acid. The exotherm control agent is preferably 
used in an amount of from about 50% to about 200% based on the weight of 
the peroxyacid compound. 
The other problems faced when peroxyacid compounds are used fall into the 
area of maintaining good bleach effectiveness. It has been recognized that 
metal ions are capable of serving as catalyzing agents in the degradation 
of the peroxyacid compounds. To overcome this problem chelating agents can 
be used in an amount ranging from 0.005% to about 1.00% based on the 
weight of the peroxyacid to tie up heavy metal ions. U.S. Pat. No. 
3,442,937, May 6 , 1969to Sennewald et al., discloses a chelating system 
comprising quinoline or a salt thereof, an alkali metal polyphosphate and, 
optionally, a synergistic amount of urea. U.S. Pat. No. 2,838,459, June 
10, 1958, to Sprout, Jr., discloses a variety of polyphosphates as 
stabilizing agents for peroxide baths. These materials are useful herein 
as stabilizing aids. U.S. Pat. No. 3,192,255, June 29, 1965, to Cann, 
discloses the use of quinaldic acid to stabilize percarboxylic acids. This 
material, as well as picolinic acid and dipicolinic acid, would also be 
useful in the compositions of the present invention. A preferred chelating 
system for the present invention is a mixture of 8-hydroxyquinoline and an 
acid polyphosphate, preferably acid sodium pyrophosphate. The latter can 
be a mixture of phosphoric acid and sodium pyrophosphate wherein the ratio 
of the former to the latter is from about 0.5:1 to about 2:1 and the ratio 
of the mixture to 8-hydroxyquinoline is from about 1:1 to about 5:1. 
In addition to the above-mentioned chelating systems to tie up heavy metals 
in the peroxyacid compositions, coating materials may also be used to 
extend the shelf life of dry granular compositions. Such coating materials 
may be, in general, acids, esters, ethers and hydrocarbons and include 
such things as wide varieties of fatty acids, derivatives of fatty 
alcohols, such as esters and ethers, derivatives of polyethyleneglycols 
such as esters and ethers and hydrocarbon oils and waxes. These materials 
aid in preventing moisture from reaching the peracid compound. Secondly, 
the coating may be used to segregate the peracid compound from other 
agents which may be present in the composition and adversely affect the 
peracid's stability. The amount of the coating material used is generally 
from about 2.5% to about 15% based on the weight of the peroxyacid 
compound. 
Agents which improve the solubility of the peroxyacid product such as 
sodium sulfate, starch, cellulose derivatives, surfactants, etc., and 
mixtures thereof are also advantageously used herein. These agents can be 
called solubilizers and are generally used in an amount from about 100% to 
about 600% based on the weight of the peroxyacid. 
Other agents such as perfumes, whitening agents and bluing agents may also 
be added to the present compositions. 
The bleaching compositions of the instant invention can also be added to 
and made a part of conventional fabric laundering detergent compositions. 
Accordingly, optional materials for the instant bleaching compositions can 
include such standard detergent adjuvants as surfactants and builders. 
Optional surfactants are selected from the group consisting of organic 
anionic, ampholytic, and zwitterionic surfactants and mixtures thereof. 
Optional builder materials include any of the conventional organic and 
inorganic builder salts including carbonates, silicates, acetates, 
polycarboxylates and phosphates. Those builders which are suitable 
buffering agents can be considered to be present in total or in part as a 
result of serving as the buffering agent described previously. If the 
instant stabilized bleaching compositions are employed as part of a 
conventional fabric laundering detergent composition, the instant 
bleaching system generally comprises from about 1 % to about 40% by weight 
of such conventional detergent compositions. Conversely, the instant 
bleaching compositions can optionally contain from about 60% to about 99% 
by weight of conventional surfactant builder materials. Further examples 
of suitable surfactants and builders are given below. 
Water-soluble salts of the higher fatty acids, i.e., "soaps," are useful as 
the anionic surfactant herein. This class of surfactants includes ordinary 
alkali metal soaps such as the sodium, potassium, ammonium and 
alkanolammonium salts of higher fatty acids containing from about 8 to 
about 24 carbon atoms and preferably from about 10 to about 20 carbon 
atoms. Soaps can be made by direct saponification of fats and oils or by 
the neutralization of free fatty acids. Particularly useful are the sodium 
and potassium salts of the mixtures of fatty acids derived from coconut 
oil and tallow, i.e., sodium or potassium tallow and coconut soaps. 
Another class of anionic surfactants includes water-soluble salts, 
particularly the alkali metal, ammonium and alkanolammonium salts, of 
organic sulfuric reaction products having in their molecular structure an 
alkyl group containing from about 8 to about 22 carbon atoms and a 
sulfonic acid or sulfuric acid ester group. (Included in the term "alkyl" 
is the alkyl portion of acyl groups.) Examples of this group of synthetic 
surfactants which can be used in the present detergent compositions are 
the sodium and potassium alkyl sulfates, especially those obtained by 
sulfating the higher alcohols (C.sub.8 -C.sub.18 carbon atoms) produced by 
reducing the glycerides of tallow or coconut oil; and sodium and potassium 
alkyl benzene sulfonates, in which the alkyl group contains from about 9 
to about 15 carbon atoms in straight chain or branched chain 
configuration, e.g., those of the type described in U.S. Pat. Nos. 
2,220,099, and 2,477,383, incorporated herein by reference. 
Other anionic surfactant compounds useful herein include the sodium alkyl 
glyceryl ether sulfonates, especially those ethers or higher alcohols 
derived from tallow and coconut oil; sodium coconut oil fatty acid 
monoglyceride sulfonates and sulfates; and sodium or potassium salts of 
alkyl phenol ethylene oxide ether sulfate containing about 1 to about 10 
units of ethylene oxide per molecule and wherein the alkyl groups contain 
about 8 to about 12 carbon atoms. 
Other useful anionic surfactants herein include the water-soluble salts of 
esters of .alpha.-sulfonated fatty acids containing from about 6 to 20 
carbon atoms in the ester group; water-soluble salts of 
2-acyloxy-alkane-1-sulfonic acids containing from about 2 to 9 carbon 
atoms in the acyl group and from about 9 to about 23 carbon atoms in the 
alkane moiety; alkyl ether sulfates containing from about 10 to 20 carbon 
atoms in the alkyl group and from about 1 to 30 moles of ethylene oxide; 
water-soluble salts of olefin sulfonates containing from about 12 to 24 
carbon atoms; and .beta.-alkyloxy alkane sulfonates containing from about 
1 to 3 carbon atoms in the alkyl group and from about 8 to 20 carbon atoms 
in the alkane moiety. 
Preferred water-soluble anionic organic surfactants herein include linear 
alkyl benzene sulfonates containing from about 11 to 14 carbon atoms in 
the alkyl group; the tallow range alkyl sulfates; the coconut range alkyl 
glyceryl sulfonates; and alkyl ether sulfates wherein the alkyl moiety 
contains from about 14 to 18 carbon atoms and wherein the average degree 
of ethoxylation varies between 1 and 6. 
Specific preferred anionic surfactants for use herein include: sodium 
linear C.sub.10 -C.sub.12 alkyl benzene sulfonate; triethanolamine 
C.sub.10 -C.sub.12 alkyl benzene sulfonate; sodium tallow alkyl sulfate; 
sodium coconut alkyl glyceryl ether sulfonate; and the sodium salt of a 
sulfated condensation product of tallow alcohol with from about 3 to about 
10 moles of ethylene oxide. 
It is to be recognized that any of the foregoing anionic surfactants can be 
used separately herein or as mixtures. 
Nonionic surfactants include the water-soluble ethoxylates of C.sub.10 
-C.sub.20 aliphatic alcohols and C.sub.6 -C.sub.12 alkyl phenols. Many 
nonionic surfactants are especially suitable for use as suds controlling 
agents in combination with anionic surfactants of the type disclosed 
herein. 
Semi-polar surfactants useful herein include water-soluble amine oxides 
containing one alkyl moiety of from about 10 to 28 carbon atoms and 2 
moieties selected from the group consisting of alkyl groups and 
hydroxyalkyl groups containing from 1 to about 3 carbon atoms; 
water-soluble phosphine oxides containing one alkyl moiety of about 10 to 
28 carbon atoms and 2 moieties selected from the group consisting of alkyl 
groups and hydroxyalkyl groups containing from about 1 to 3 carbon atoms; 
and water-soluble sulfoxides containing one alkyl moiety of from about 10 
to 28 carbon atoms and a moiety selected from the group consisting of 
alkyl and hydroxyalkyl moieties of from 1 to 3 carbon atoms. 
Ampholytic surfactants include derivatives of aliphatic or aliphatic 
derivatives of heterocyclic secondary and tertiary amines in which the 
aliphatic moiety can be straight chain or branched and wherein one of th 
aliphatic substituents contains from about 8 to 18 carbon atoms and at 
least one aliphatic substituent contains an anionic water-solubilizing 
group. 
Zwitterionic surfactants include derivatives of aliphatic quaternary 
ammonium, phosphonium and sulfonium compounds in which the aliphatic 
moieties can be straight or branched chain, and wherein one of the 
aliphatic substituents contains from about 8 to 18 carbon atoms and one 
contains an anionic water-solubilizing group. 
The instant granular compositions can also comprise those detergency 
builders commonly taught for use in laundry compositions. Useful builders 
herein include any of the conventional inorganic and organic water-soluble 
builder salts, as well as various water-insoluble and so-called "seeded" 
builders. 
Inorganic detergency builders useful herein include, for example, 
water-soluble salts of phosphates, pyrophosphates, orthophosphates, 
polyphosphates, phosphonates, carbonates, bicarbonates, borates and 
silicates. Specific examples of inorganic phosphate builders include 
sodium and potassium tripolyphosphates, phosphates, and 
hexametaphosphates. The polyphosphonates specifically include, for 
example, the sodium and potassium salts of ethylene diphosphonic acid, the 
sodium and potassium salts of ethane 1-hydroxy-1,1-diphosphonic acid, and 
the sodium and potassium salts of ethane-1,1,2-triphosphonic acid. 
Examples of these and other phosphorus builder compounds are disclosed in 
U.S. Pat. Nos. 3,159,581; 3,213,030; 3,422,137; 3,400,176 and 3,400,148, 
incorporated herein by reference. Sodium tripolyphosphate is an especially 
preferred, water-soluble inorganic builder herein. 
Non-phosphorus containing sequestrants can also be selected for use herein 
as detergency builders. Specific examples of non-phosphorus, inorganic 
builder ingredients include water-soluble inorganic carbonate, 
bicarbonate, borate and silicate salts. The alkali metal, e.g., sodium and 
potassium, carbonates, bicarbonates, borates (Borax) and silicates are 
particularly useful herein. 
Water-soluble, organic builders are also useful herein. For example, the 
alkali metal, ammonium and substituted ammonium polyacetates, 
carboxylates, polycarboxylates, succinates, and polyhydroxysulfonates are 
useful builders in the present compositions and processes. Specific 
examples of the polyacetate and polycarboxylate builder salts include 
sodium, potassium, lithium, ammonium and substituted ammonium salts of 
ethylene diamine tetraacetic acid, nitrilotriacetic acid, oxydisuccinic 
acid, mellitic acid, benzene polycarboxylic acids, and citric acid. 
Highly preferred non-phosphorous builder materials (both organic and 
inorganic) herein include sodium carbonate, sodium bicarbonate, sodium 
silicate, sodium citrate, sodium oxydissucinate, sodium mellitate, sodium 
nitrilotriacetate, and sodium ethylenediaminetetraacetate, and mixtures 
thereof. 
Another type of detergency builder material useful in the present 
compositions and processes comprises a water-soluble material capable of 
forming a water-insoluble reaction product with water hardness cations in 
combination with a crystallization seed which is capable of providing 
growth sites for said reaction product. 
Specific examples of materials capable of forming the water-insoluble 
reaction product include the water-soluble salts of carbonates, 
bicarbonates, sequicarbonates, silicates, aluminates and oxalates. The 
alkali metal, especially sodium, salts of the foregoing materials are 
preferred for convenience and economy. 
Another type of builder useful herein includes various substantially 
water-insoluble materials which are capable of reducing the hardness 
content of laundering liquors, e.g., by ion-exchange processes. Examples 
of such builder materials include the phosphorylated cloths disclosed in 
U.S. Pat. No. 3,424,545. Bauman, issued Jan. 28, 1969, incorporated herein 
by reference. 
The complex aluminosilicates, i.e., zeolite-type materials, are useful 
presoaking/washing adjuvants herein in that these materials soften water, 
i.e., remove Ca.sup.++ hardness. Both the naturally occurring and 
synthetic "zeolites" , especially zeolite A and hydrated zeolite A 
materials, are useful for this builder/softener purpose. A description of 
zeolite materials and a method of preparation appears in Milton, U.S. Pat. 
No. 2,882,243, issued Apr. 14, 1959, incorporated herein by reference. 
COMPOSITION PREATION 
The bleaching granules of the present compositions are prepared in any 
conventional manner such as by admixing ingredients, by agglomeration, by 
compaction or by granulation. 
In one method for preparing the instant compositions a peroxyacid-water 
mixture containing from about 50% by weight to about 80% by weight of 
water is combined in proper proportions with any optional components to be 
utilized within the bleaching granules themselves. Common optional 
components, as indicated herein earlier, are an exotherm control agent, a 
chelating agent and a solubilizer such as sodium sulfate. Such a 
combination of ingredients is then thoroughly mixed and subsequently 
pumped into spray tower to form solid, essentially spherical granules. The 
bleaching granules can then be dried to the appropriate water content. 
Bleaching granules prepared in this manner are then admixed with other 
granules of buffering agent and optional detergent composition materials, 
if such are desired. Actual particle size of either the bleach-containing 
granules, the buffering agent granules or optional granules of additional 
material is not critical. If, however, compositions are to be realized 
having commercially acceptable flow properties, certain granule size 
limitations are highly preferred. In general, all granules of the instant 
compositions preferably range in size from about 100 microns to 3000 
microns, more preferably from about 100 microns to 1300 microns. 
Additionally, flowability is enhanced if particles of the present invention 
are of approximately the same size. Therefore, preferably the ratio of the 
average particle sizes of the bleach-containing granules, buffering agents 
and optional granules of other materials varies between 0.5:1 and 2.1:1 
when any two of the granules are compared. 
Bleaching compositions of the present invention are utilized by dissolving 
them in water in an amount sufficient to provide from about 1.0 ppm to 100 
ppm available oxygen, preferably from about 15 to about 45, in solution. 
Generally, this amounts to about 0.01% to 0.2% by weight of composition in 
solution. Fabrics to be bleached are then contacted with such aqueous 
bleaching solutions.

The bleaching compositions of the instant invention are illustrated by the 
following examples: 
EXAMPLE I 
The following is a composition within the scope of the present invention. 
______________________________________ 
Bleach Granule 
Diperoxydodecanedioic Acid (DPDA) 
18.20% 
Dodecanedioic Acid (DA) (Impurity) 
3.80 
Boric Acid (Exotherm Control Agent) 
22.20 
C.sub.13 Linear Alkyl Benzene Sulfonate 
(Solubilizer) 4.36 
8-Hydroxyquinoline 0.03 
Phosphoric Acid (Chelating System) 
0.04 
Sodium Pyrophosphate 0.05 
Sodium Sulfate (Diluent and 
50.32 
Solubilizer) 
Mineral Oil (Coating) 1.00 
100.00 
Buffer Granule 
Sodium Carbonate 100.00 
______________________________________ 
Ratio of amount of bleach granules to amount of buffer granules=80:20. 
The above bleach granules are prepared by forming a wet filter cake oF DPDA 
and the DA impurity. The DPDA is formed by the process described in U.S. 
Pat. No. 2,813,896, Nov. 19, 1957, to Krimm, incorporated herein by 
reference earlier. The filter cake, containing about 40% solids, is 
subsequently blended with the other ingredients, except the mineral oil. 
The alkyl sulfonate and the chelating system are added first followed by 
the addition of boric acid and sodium sulfate. This mixture is then 
sprayed into a cold tower operating with counter-current air flow. The 
spraying forms particulate granules, which granules are subsequently dried 
in a fluid bed dryer to a moisture level of about 0.2%. As a final step 
the granules are sprayed with mineral oil is rotating drum apparatus. The 
mineral oil serves to make the granules less dusty. in a 
The buffering granules (sodium carbonate) are formed such that the particle 
size distribution is similar to the particle size of the bleach granules. 
This is to provide for good flow characteristics and minimal product 
seregation. 
The composition described above will provide a was pH of about 9.0 when 
dissolved in water. Another composition, outside the scope of the present 
invention, is prepared with no sodium carbonate present. 
EXAMPLE II 
The compositions of Example I are tested to determine their ability to 
brighten and whiten fabrics, remove stains and cause color damage to nylon 
fabrics. The test procedures are given below. 
Materials 
Dingy fabrics representing articles constructed of various fabric types are 
obtained. The fabrics are labeled so that they can be identified for 
grading purposes after the washing treatments. One-half of the fabrics are 
treated with one treatment and the other half with the second treatment. 
In addition to the dingy fabrics colored swatches are included with each 
treatment. The swatches include a sensitive light blue, nylon swatch. 
With each load additional fabrics are added to make a total load weight of 
five pounds. 
Treatment Conditions 
Each treatment is used with a separate fabric load. The wash solution is 17 
gallons of 100.degree. F. water which contains in addition to the fabrics, 
96 grams (the recommended detergent usage) of an anionic surfactant and 
the test bleach. The bleach systems are used in an amount sufficient to 
supply 20 parts per million (ppm) available oxygen. The total wash time is 
14 minutes. 
The washed fabrics are rinsed in warm water using a 4 minute cycle. The 
fabrics are finally dried using an electric dryer with a 45 minute cycle. 
Dingy Fabric Grading 
Expert judges are used to grade the dingy fabrics visually for stain 
removal and whiteness/brightness. The judges grade fabric using a scale of 
0 to 100. The "0" value represents a grade given to a low control product 
while the "100" value is representative of the grade given to a high 
control product. The grades are totalled for each treatment and divided by 
the number of articles graded. The average grades are representative of 
the effectiveness of the treatments. 
Nylon Color Damage Test 
The light blue nylon swatch is used for measuring color loss. The swatch is 
evaluated using a Hunter Color and Color Difference Meter, Model D-25, 
before the test treatment is performed, as well as after. The difference 
in color is then determined using the following equation: 
EQU .DELTA.E=.sqroot.(.DELTA.L).sup.2 +(.DELTA.a).sup.2 +(.DELTA.b).sup.2 
The values under the square root are the differences in Hunter Color Space 
coordinates found between the initial fabric color and the color after 
treatment. The magnitude of .DELTA.E determines the extent of nylon color 
damage (i.e., large values mean severe color damage while small values 
mean minor damage). 
Results 
The average grades for whiteness/brightness and stain removal, as well as 
the .DELTA.E values are given below. The buffered composition treatment 
has a pH of 9.0 while the unbuffered composition treatment has a pH of 8.3 
as the result of the alkalinity of the anionic detergent. 
______________________________________ 
Whiteness/ 
Stain Nylon Color 
Brightness 
Removal Damage .increment. E 
______________________________________ 
Diperoxydodecanedioic 
Acid pH 9.0 80 78 1.4 
Diperoxydodecanedioic 
Acid pH 8.3 90 80 6.6 
______________________________________ 
It is seen that the pH 9.0 composition is significantly better than the pH 
8.3 composition in terms of nylon color damage while being essentially 
equivalent in terms of segregation. and stain removal. 
Results similar to those outlined above are achieved when sodium carbonate 
is replaced by an equivalent amount of another buffer such as sodium 
borate decahydrate, sodium phosphate or sodium pyrophosphate.