Liquid oxygenic bleaching composition

A liquid bleaching composition is acidic with a PH value of 1.5 to 6 and improved in stability. It comprises: PA0 (a) 0.5 to 10% by weight of hydrogen peroxide, PA0 (b) 0.1 to 20% by weight of an anionic surfactant, PA0 (c) 0.1 to 20% by weight of a nonionic surfactant, PA0 (d) 0.05 to 5% by weight of a polyacrylic acid having an average molecular weight of 1,000 to 100,000 or a salt thereof and/or a maleic polymer having an average molecular weight of 500 to 100,000, and PA0 (e) 0.0001 to 1% by weight of a polyphosphoric acid, a salt thereof, an amino phosphonic acid, a salt thereof, or a diphosphonic acid or a salt thereof.

The present invention relates to an acidic liquid bleaching composition. In 
particular, the present invention relates to an acidic liquid bleaching 
composition having an excellent storage stability and high bleaching 
power. 
Prior Art 
Liquid bleaching agents based on hydrogen peroxide for clothes can be 
classified as either being alkaline or acidic. 
The decomposition of hydrogen peroxide is accelerated under alkaline 
conditions and retarded under acidic conditions. Therefore, acidic 
bleaching agents have an insufficient storage stability at high 
temperatures, though they are relatively stable during the storage at low 
temperatures. 
Investigations on the improvement of storage stability of liquid bleaching 
agents containing hydrogen peroxide have been made heretofore. For 
example, Japanese Patent Publication No. 7774/1965 discloses a weakly 
acidic liquid bleaching agent having excellent storage stability which 
comprises acidic sodium pyrophosphate, neutral sodium pyrophosphate and 
neutral potassium pyrophosphate. Japanese Patent Laid-Open No. 52784/1974 
discloses a stable liquid bleaching agent comprising an organic acid 
selected from the group consisting of alkylidenediphosphonic acids, 
ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and 
nitrilotrimethylenephosphonic acid, a soluble tin salt and an ammonium 
salt and having a pH in the range of 0.5 to 7. Japanese Patent Laid-Open 
No. 103386/1977 discloses a hydrogen peroxide stabilizer comprising 
poly-.alpha.-hydroxyacrylic acid. Japanese Patent Laid-Open No. 10309/1979 
discloses that a liquid prepared by adding water to a magnesium compound 
and an acid to conduct neutralization, thereby forming a hydrophilic 
complex inhibits the decomposition of hydrogen peroxide at pH 4 to 6. 
Japanese Patent Laid-Open No. 108500/1980 discloses a stable liquid 
bleaching agent having a pH of 1.8 to 5.5 which comprises an acid selected 
from the group consisting of organic acids, phosphoric acid and boric acid 
and a nitrogenous compound. Japanese Patent Laid-Open No. 76161/1980 
discloses that when a poly-.alpha.-hydroxyacrylic salt is incorporated 
into an alkaline hydrogen peroxide bleaching agent containing a 
polyphosphoric salt as the stabilizer, a synergistic stabilization effect 
is exhibited. Japanese Patent Laid-Open No. 154457/1982 discloses a 
stabilizing assistant for a hydrogen peroxide bleaching agent which 
comprises a copolymer of acrylic acid and an acrylic ester and/or 
polyethylene glycol methacrylate. and Japanese Patent Laid-Open No. 
185797/1987 discloses a stabilizer for a hydrogen peroxide bleaching agent 
which comprises a combination of a poly-.alpha.-hydroxyacrylic salt and an 
organic phosphonic salt. 
The hydrogen peroxide bleaching agents containing the above-described 
stabilizers have defects that a high-temperature storage stability thereof 
is insufficent and that a sufficient bleaching effect cannot be obtained 
under acidic conditions. 
SUMMARY OF THE INVENTION 
After intensive investigations, the present inventors have found that an 
acidic hydrogen peroxide bleaching agent having a remarkably improved 
storage stability at high temperatures and high bleaching power can be 
obtained by incorporating a polyacrylic polymer and/or maleic polymer 
having a specified molecular weight and a specified phosphorus compound 
into a specified surfactant. The present invention has been completed on 
the basis of this finding. 
Thus the present invention provides a liquid oxygenic bleaching composition 
comprising: 
(a) 0.5 to 10% by weight of hydrogen peroxide, 
(b) 0.1 to 20% by weight of an anionic surfactant, 
(c) 0.1 to 20% by weight of a nonionic surfactant, 
(d) 0.05 to 5% by weight of a polyacrylic acid having an average molecular 
weight of 1,000 to 100,000 or a salt thereof and/or a maleic polymer 
having an average molecular weight of 500 to 100,000, and 
(e) 0.0001 to 1% by weight of a polyphosphoric acid, a salt thereof, an 
amino phosphonic acid, a salt thereof, having the formula (I) or a 
diphosphonic acid or a salt thereof, having the formula (II): 
##STR1## 
wherein n represents an integer of 0 to 5, and M.sup..sym. represents 
H.sup..sym. or an alkali metal ion, 
##STR2## 
and wherein X is hydrogen or an alkyl having 1 to 4 carbonation, Y is 
hydrogen or an alkyl having 1 to 4 carbonation and M is hydrogen ion or an 
alkali metal ion, 
said composition having a pH value in the range of 1.5 to 6. 
In the present invention, hydrogen peroxide (a) used as the bleaching base 
is incorporated into the composition in an amount of 0.5 to 10% by weight, 
preferably 3 to 7% by weight. 
Examples of the anionic surfactant (b) used in the present invention 
include linear and branched alkylbenzenesulfonate salts, alkyl and alkenyl 
ether sulfate salts, alkyl- and alkenylsulfate salts, olefinsulfonate 
salts, alkanesulfonate salts and saturated and unsaturated fatty acid 
salts. Examples of the nonionic surfactant (c) include polyoxyalkylene 
alkyl and alkenyl ethers, polyoxyethylene alkylphenyl ethers, higher fatty 
acid alkanolamides and alkylene oxide adducts thereof, sucrose fatty acid 
esters, fatty acid glycerol monoesters, alkylamine oxides, Pluronic 
surfactants, sorbitan fatty acid esters and ethylene oxide adducts 
thereof. 
The sum of the anionic surfactant (b) and nonionic surfactant (c) in the 
composition is 0.1 to 20% by weight, preferably 3 to 15% by weight. The 
weight ratio of the component (b) to component (c) is 1/5 to 5/1, 
preferably 1/3 to 3/1. Particularly preferred anionic surfactants (b) are 
linear alkyl(C.sub.8 to C.sub.18) benzenesulfonate salts, alkyl(C.sub.8 to 
C.sub.18) ether (with the number of added ethylene molecules of 1 to 10) 
sulfate salts, .alpha.-olefin(C.sub.12 to C.sub.18) sulfonate salts and 
alkyl(C.sub.8 to C.sub.18) sulfate salts. Particularly preferred nonionic 
surfactants (c) are polyoxyethylene (with the molar number of addition of 
1 to 30) alkyl ethers. 
The polyacrylic acid or its salt used as the component (d) in the present 
invention is one having an average molecular weight of 1,000 to 100,000, 
preferably 2,000 to 20,000. When the average molecular weight is less than 
1,000 or above 100,000, the stabilizing effect is rapidly reduced. 
Carbopol often used as a thickening agent for a liquid acidic hydrogen 
peroxide bleaching agent is a polyacrylic acid having a quite high 
molecular weight and partially crosslinked, which is different from the 
non-crosslinked polyacrylic acid used in the present invention. 
Examples of the maleic polymer used as the component (d) include maleic 
homopolymers and copolymers of maleic acid with another vinyl monomer 
(including partially or completely neutralized salts of them). The 
copolymers include those of maleic acid with a vinyl monomer selected from 
the group consisting of, for example, acrylic acid, methacrylic acid, 
acrylic esters, metacrylic esters and vinyl acetate. Among them, the 
copolymer of acrylic acid or methacrylic acid with maleic acid is 
preferred. The monomer ratio of maleic acid to the other monomer is 
preferably in the range of 90/10 to 40/60. The maleic polymers used herein 
are those having each an average molecular weight of 500 to 100,000, 
preferably 500 to 10,000 and particularly preferably 600 to 3,000. When 
the average molecular weight of the polymer is less than 500 or above 
100,000, the stabilizing effect is rapidly reduced. The polymers (d) are 
incorporated into the composition in a total amount of 0.05 to 5% by 
weight, preferably 0.5 to 3% by weight. When the amount of the polymer is 
less than 0.05% by weight, no sufficient effect can be obtained and, on 
the contrary, when it exceeds 5% by weight, the polymer might cause phase 
separation. 
The polyphosphoric acids and salts thereof herein used as the component (e) 
include pyrophosphoric acid, tripolyphosphoric acid, hexametaphosphoric 
acid and salts of them with sodium and potassium. 
Particularly preferred examples of the amino phosphonic acids and salts 
thereof represented by the general formula (I) are those wherein n is 0 to 
2. The salts of them include sodium and potassium salts. The component (e) 
is incorporated into the composition in an amount of 0.0001 to 1% by 
weight, preferably 0.001 to 0.1% by weight, and particularly preferably 
0.001 to 0.05% by weight. 
The composition of the present invention contains the balance of water in 
addition to the above-described components (a) to (e). If necessary, it 
may further contain an alcohol such as ethanol, isopropanol or ethylene 
glycol, as well as a thickening agent, flavor, dyestuff, fluorescent dye, 
enzyme, etc. 
The pH of the stocks solution of the composition of the present invention 
is adjusted to 1.5 to 6, preferably 2.0 to 4.5 with an inorganic acid such 
as hydrochloric acid or sulfuric acid or an organic acid such as 
p-toluenesulfonic acid or citric acid. When the pH of the composition 
exceeds 6, the storage stability is seriously reduced. 
In the invention, dyestuffs can be used with stability under the acidic 
condition. Organic pigments include color index vat blue 4, color index 
vat blue 6, color index pigment blue 22, color index vat red 23, color 
index pigment blue 15, color index pigment blue 17 and color index pigment 
green 36. Acidic dyestuffs include color index acid blue 229, color index 
acid blue 9, color index acid blue 112, Alizarine Fast Blue ERL (tradename 
of Yamada Chemical Co.), Alizarine Fast Blue 3GL (tradename of Yamada 
Chemical Co.) and Fastogen Blue 5380 (tradename of DIC Co.). Metal 
dyestuffs include color index acid read 198, color index acid blue 158, 
color index acid green 35, color index direct blue 86 and color index 
direct blue 199.

EXAMPLES 
The following Examples will further illustrate the present invention, which 
by no means limit the invention. 
EXAMPLE 1 
Bleaching compositions listed in Table 1 were prepared and subjected to the 
following tests: 
(1) Storage stability (accelerated test): 
0.5 ppm (in terms of iron ion) of ferric chloride was added to each of the 
bleaching compositions listed in Table 1. A 1-(glass vessel shown in FIG. 
1 was filled with the mixture and immersed in a water bath at 70.degree. 
C. for 30 h to determine the quantity of a gas thus generated. 
(2) Bleaching rate: 
Evaluation method: 
Each of the bleaching agents having a composition as specified in Table 1 
was dissolved in city water at 20.degree. C. to prepare a solution having 
an available oxygen concentration of 0.05%. Five cloths stained with black 
tea prepared as will be described below were immersed in 300 m of each 
solution of the bleaching agent prepared as described above at 20.degree. 
C. for 30 min, rinsed with city water, and dried. The bleaching rate was 
calculated according to the following equation: 
##EQU1## 
The reflectivity was determined with a colorimetric color difference Meter 
N-DR 101-DP, mfd. by Nihon Denshoku. 
Cloths stained with black tea: 
80 g of Nitto black tea leaves (yellow package) was boiled in 3 l of 
ion-exchanged water for about 15 min and then filtered through a desized 
bleached cotton cloth. A cotton shirting cloth #2003 was immersed in the 
filtrate and boiled for about 15 min. Thereafter, the liquid was left to 
cool for about 2 h. The cloth was naturally dried, washed with water until 
the wash solution was no more colored, then dehydrated and pressed. It was 
cut into test pieces (8.times.8 cm) to be subjected to the tests. 
The results are given in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Present invention 
Comparative 
Composition (% by weight) 
1 2 3 4 1 2 3 4 5 
__________________________________________________________________________ 
Hydrogen peroxide 5 5 5 5 5 5 5 5 5 
Polyacrylic acid*.sup.1 
2 1 1 2 2 
Maleic acid/acrylic acid copolymer*.sup.2 
2 1 
Polyoxyethylene alkyl ether*.sup.3 
4 5 3 4 4 3 4 3 
Sodium linear alkylbenzenesulfonate*.sup.4 
7 4 5 5 7 7 
Sodium tripolyphosphate 
0.1 
Sodium hexametaphosphate 
0.01 0.1 
Sodium aminophosphonate*.sup.5 
0.01 
1-hydroxyethylidene-1,1-di- 0.1 
phosphonic acid*.sup.7 
Ion-exchanged water 
B*.sup.6 
B B B B B B B B 
pH 2.8 
2.5 
3.0 
3.0 
2.6 
2.4 
2.5 
2.4 
2.4 
Storage stability 
amount of gas 
2 3 2 2 56 65 53 57 30 
formed (ml) 
Bleaching rate (%) 11.5 
11.2 
11.3 
11.3 
10.0 
5.3 
6.0 
7.3 
7.0 
__________________________________________________________________________ 
(Notes) 
*.sup.1 polyacrylic acid: sodium salt having average molecular weight of 
8,000, 
*.sup.2 maleic acid/acrylic acid copolymer: sodium salt having average 
molecular weight of 1,500, 
*.sup.3 polyoxyethylene alkyl ether: alkyl (C.sub.12 to C.sub.13) ethylen 
oxide (10 mol) adduct, 
*.sup.4 sodium linear alkylbenzenesulfonate: alkyl: C.sub.12, 
*.sup.5 sodium aminophosphonate of the following formula: 
##STR3## 
*.sup.6 B: the balance 
*.sup.7 Dequest 2010 (tradename) being available from Monsanto, having th 
formula: 
##STR4##