US3393153A - Novel liquid bleaching compositions - Google Patents

Description

United States Patent NOVEL LIQUID BLEACHING COMPOSITIONS Roger E. Zimmerer, Springfield Township, Hamilton County, and Warren I. Lyness, Mount Healthy, Ohio,

assignors, to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Dec. 20, 1965, Ser. No. 515,223

13 Claims. (Cl. 252-95) ABSTRACT OF THE DISCLOSURE Stable aqueous compositions having a pH of from about 10.5 to about 13.0 consisting essentially of Water, from about 1.0% to about alkali metal hypochlorite bleach; from about 0.002% to about 2.0% of a hypochlorite bleach-compatible optical brightener; and from about 0.1% to about 2.0% of a particulate, hypochlorite bleach-stable, brightener-stable, insoluble and dispersible stabilizing agent.

This invention relates to a new composition of matter useful in laundry operations. More specifically, a stable aqueous composition containing hypochlorite bleach, an optical brightener, and a stabilizing agent, has been discovered. The compositions of the invention, when used in laundry operations in the same manner as conventional liquid hypochlorite bleach, provide substantial bleaching and optical brightening, a desirable result not heretofore obtainable from a single liquid composition.

Bleaches, in a common sense and as used herein, are defined a's laundry products which aid in the removal of stains and soil from textiles by virtue of their power to oxidize materials. An aqueous solution containing about 5% sodium hypochlorite is an example of the most popular and generally used laundry bleach.

Optical brighteners (or brighteners), as used herein, are defined as chemicals which are adsorbed by textile fibers and thereby impart to the textile an improved degree of whiteness 0r brightness (fluorescence) by means of their chemical ability to absorb ultraviolet radiation and re-emit visible radiation.

Optical brighteners have found Widespread use as components of household detergent compositions. In fact, to achieve the degree of whiteness desired in the wash by most consumers, a combination of bleaching and optical brightening is generally required. This requirement is usually met by using a brightener-containing detergent composition as the primary Wash-ing agent combined with (a) the subsequent addition of hypochlorite bleach to the wash water, or (h) prior use of a hypochlorite bleach in a separate step.

It has long been deemed desirable to consolidate this bleaching/ brightening effect into a single step process, e.g., by using a product which contains both a bleach and an optical brightener. Canadian Patent 560,574, for example, discloses a specific optical brightener contained in a dry (powder) bleach composition. However, previous attempts to create a stable, practical and useful aqueous bleach product containing both hypochlorite bleach and an optical brightener have failed because of brightener-bleach incompatibility, i.e., the efficacy of the optical brightener is destroyed by the bleach and/or the oxidizing power of the bleach is destroyed by the optical brightener.

Accordingly, it is a primary object of this invention to provide a stable aqueous composition capable of rendering both chemical bleaching and optical brightening effects.

It is another object of this invention to provide a stable "ice aqueous composition containing hypochlorite bleach and an optical brightener.

It is still another object of the invention to provide a stable aqueous composition consisting of hypochlorite bleach, an optical brightener, and a stabilizing agent.

It is a further and preferred object of this invention to provide a stable aqueous composition consisting of hypochlorite bleach, a uniformly suspended optical brightener, and a stabilizing agent.

It is an additional object of this invention to provide a method of preparing stable aqueous compositions containing hypochlorite bleach and an optical brightener.

These and other objects are achieved in accordance with this invention, which involves the discovery that certain selected optical brighteners can be successfully incorporated with hypochlorite bleach in aqueous compositions if the pH of said compositions is within a particular range and a stabilizing agent, as hereinafter defined, is included.

In general, this invention comprises a stable aqueous composition having a pH ranging from about 10.5 to about 13.0 and consisting of:

(A) from about 1.0% to about 10% alkali metal hypochlorite bleach;

(B) from about 0.002% to about 2.0% hypochlorite bleach-compatible optical brightener, as hereinafter defined; and

(C) from about 0.1% to about 2.0% stabilizing agent,

as hereinafter defined.

The compositions of this invention are capable of providing both chemical bleaching and optical brightening effects. Further, they are stable over an extended period of time so that they may be successfully packaged, shipped and stored without rendering inefiective the whitening action of the optical brightener or the oxidizing action of the bleach. In compositions which represent preferred embodiments of the invention, the stabilizing agent maintains the brightener in a stable state of uniform suspension and/or opacifies the solution.

The hypochlorite bleach component is present in the compositions of this invention in an amount ranging from about 1% to about 10%, preferably from about 3% to about 7%, with about 5.2% being especially desirable.

The bleach component can be any one of the alkali metal hypochlorites. Examples of such useful bleaches are sodium hypochlorite, potassium hypochlorite, lithium hypochlorite, and the like. However, sodium hypochlorite is highly preferred because of its superior properties and its ready availability. As will be discussed hereinafter, conventional sodium hypochlorite bleach, which is generally commercially available as a 5.25% aqueous solution, is a convenient starting material for use in formulating the compositions of this invention.

The optical brightener is present in the compositions of this invention in an amount ranging from 0.002% to about 2.0%, preferably from about 0.01% to about 0.1% with about 0.05% being especially preferred.

The optical brightener must be chemically stable and substantially insoluble, i.e., more than 99% of the amount employed remains undissolved, in the aqueous hypochlorite-containing compositions of this invention, e.g., in solutions containing about 5% hypochlorite, but it must be sufficiently soluble, i.e., less than 25% remains undissolved at washing machine conditions, e.g., in aqueous solutions containing about 0.02% hypochlorite, so that it can be eifectively deposited on desired textile substrata. Optical brighteners that have the above-outlined stability and solubility characteristics when incorporated into the compositions of this invention are referred to herein and in the appended claims as hypochlorite bleach-compatible.

Examples of such bleach-compatible optical brighteners are listed below.

1-imidazolyl-2-oxazolylethylenes, e.g., l-(benzimidazol- 2-yl)-2-(benzoxazol-2-yl)ethylene:

2-aryl-5-oxazolylthiophenes, e.g., 2-(5-phenylbenzoxazol 2 yl) 5 phenylthiophene or sulfonated products thereof:

Sulfonated benzoxazolylstilbenes, e.g., sulfonated 4-(5"- phenylbenzoxazol-2-yl)-4-stilbene carboxylic acid:

chlorite, even when exposed thereto for extended periods of time, e.g., several weeks of storage.

It is surprising that the optical brighteners disclosed herein are stable at dilute concentrations of bleach and even more stable at the high concentrations of bleach found in the compositions of this invention, because, in the presence of intermediate concentrations of bleach, e.g., from about 0.1% to about 0.8% hypochlorite, these optical brighteners are not stable and their efficacy is destroyed. This unexpected result is apparently related to the solubility characteristics exhibited by the above-listed optical brighteners in the compositions of this invention.

The stabilizing agent is present in the compositions of the invention in an amount ranging from about 0.1% to about 2.0%, preferably from about 0.5% to about 1.5% with about 1.0% being particularly preferred.

Stabilizing agents useful for the present invention must be chemically non-reactive with the other ingredients of the composition, especially with the bleach and optical brightener i.e., this component must be chemically stable in the presence of both the bleach and the optical brightener. Further, the stabilizing agent must be insoluble and dispersible in the bleach-containing solutions of the invention. Additionally the stabilizing agent must be particulate, i.e., it must have a mean particle diameter ranging from about 0.01 4 to about Thus, the term stabilizing agent is defined herein and in the appended claims as a particulate material that is hypochlorite bleach-stable, brightener-stable, insoluble, and dispersible in the compositions of this invention. Preferably, in addition to exhibiting these necessary characteristics, the stabilizing agent is also capable of uniformly suspending the optical brightener component in the solutions of this invention.

Of the above-exemplified optical brighteners, those preferred for use in the compositions of this invention are: stilbylmonotriazoles, e.g., sodium 4-(2H-naphtho[l',2'-d] triazol-2"-yl)-2-stilbenesulfonate, sodium 4-(2H-5-sulfonaphtho l ,2'-d] -triazol-2"-yl -2-cyanostilbene, sodium 4 (4'H acenaphtho[4',5' d]triazol 2 yl) 2 stilbenesulfonate and other stilbylmonotriazoles such as those disclosed in British patent 717,978, granted September 14, 1965, to Hickson and Welch Limited, dibenzothiophenedioxides, e.g., disodium 3,7-bis(4-methoxybenzamido)-2,8-disulfodibenzothiophene-5,5-dioxide; l,2-bis(imidazolyl) ethylenes, e. g., 1,2-bis[1'-(2"-hydroxyethyl)benzimidazol-2'-yl)ethylene; 2- aryl-S-oxazolylthiophenes or sulfonated derivatives thereof, e.g., monosulfonated 2-(5'- phenylbenzoxazol-2-yl)-5-phenylthiophene; l-imidazolyl- 2-oxazolylethylenes, e.g., 1-(benzimidazol-2'-yl)-2-(benzoxazol-2"-yl ethylene.

The most highly preferred optical brighteners are the stilbylmonotriazoles such as sodium 4-(2'H-naphtho[l', 2' d] triazol 2" yl)-2-stilbenesulfonate and sodium 4- (2H-5'-sulfonaphtho[1',2-d] triazol-2"-yl) 2 cyanostilbene.

Of these optical brighteners described above which are listed as sodium salts, other alkali metal salts thereof, e.g., potassium salts, can also be satisfactorily used.

Some of the above-listed optical brighteners have been heretofore disclosed as bleach-stable. However, it is generally recognized that bleach-stable in this conventional sense simply means that these optical brighteners are not rendered ineifective when exposed to dilute solutions of bleach for limited periods of time, e.g., at washing machine conditions as hereinbefore defined for up to twenty or thirty minutes. It has now been discovered, in accordance with the compositions of this invention, that the above-listed optical brighteners are not destroyed in the presence of concentrated bleach, e.g., 1%10% hypo- Moreover, certain stabilizing agents tend to make the solutions of the invention opaque; these stabilizing agents are preferred because of the desirability of opaque liquid laundry products, for appearance purposes, for visual ease in measuring and pouring, and for distinguishing liquid bleaches from other clear liquids such as Water and vinegar.

The precise function of the stabilizing agent in promoting bleach-brightener compatibility in the compositions of this invention is not completely understood; however a theory, which is not to be limitive, can be advanced. The role of the stabilizing agent is believed to be that of a crystal modifier, i.e., it retards natural growth and agglomeration of the optical brightener crystals and this in turn advantageously affects the solubility characteristics of the optical brightener.

An example of a material useful as a stabilizing agent herein is colloidal (particulate) silica, preferably having a mean particle diameter ranging from about 0.0l,u to about 0.05,:t.

Preferred for use as stabilizing agents herein are particulate polymers having a mean particle diameter ranging from about 0.01 to about 30p. and an average molecular weight ranging from about 10,000 to about 3,000,- 000 (molecular weights stated herein are measured by the intrinsic viscosity method). Examples of such particulate stabilizing agents are polystyrene, oxidized polystyrene having an acid number of 20 to 40, sulfonated polystyrene having an acid number of 10 to 30, polyethylene, oxidized polyethylene having an acid number of 10 to 30, sulfonated polyethylene having an acid number of 5 to 25, polypropylene, oxidized polypropylene having an acid number of 10 to 30 and sulfonated polypropylene having an acid number of 5 to 25. Additional examples of such polymeric stabilizing agents are copolymers of styrene with monomers such as maleic anhydride, acrylonitrile, methacrylic acid and lower alkyl esters of methacrylic acid.

Particularly preferred materials useful as stabilizing agents in the compositions of the invention are copolymers of styrene with certain ester and acid monomers such as methyl or ethyl acrylate, methyl or ethyl maleate, vinyl acetate, acrylic, maleic or fumaric acid, and mixtures thereof, the mole ratio of ester and/or acid to styrene preferably being in the range of 1 ester and/or acid (monomer) unit per each 4 to 40 styrene units, said copolymers having a mean particle diameter ranging from about 0.05;]. to about 1.0 1, and a molecular weight ranging from about 500,000 to about 2,000,000. Examples of the above-defined polystyrene materials which are highly preferred as stabilizing agents in the compositions of this invention are (a) a copolymer of styrene and methyl acrylate with a ratio of about 1 methyl acrylate unit to about 6 styrene units, and having a mean particle diameter of about 0.2 and an average molecular weight of about 1,000,000, and (b) a copolymer of styrene, methyl acrylate, and acrylic acid with a ratio of about 1.7 methyl acrylate units and about 1 acrylic acid unit per 16 styrene units, and having a mean particle diameter of about 0.1/L and an average molecular weight of about 1,000,000.

Many of the above-listed materials useful herein as stabilizing agents further serve to maintain the optical brightener in a stable state of uniform suspension. This particular physical form of the composition renders outstanding results in the area of bleach-brightener compatibility, and in addition, provides a convenient product adaptable for widespread use, e.g., uniform results are obtained without physical shaking or stirring of the composition prior to pouring. Colloidal silica, polyethylene, polystyrene, and the above-exemplified cOpolymers of styrene, represent examples of such stabilizing agents which also uniformly suspend the optical brightener. The styrene copolymers with acid and ester monomers listed in the above paragraph are particularly preferred for their ability to uniformly suspend the optical brightener. In addition, these highly preferred polystyrene-type materials serve to opacify the compositions of the invention thus rendering a desirable and practical effect.

As stated previously, the pH of the compositions of this invention ranges from about 10.5 to about 13.0. It has been discovered that this pH range is critical for bleach-brightener compatibility and for a practical and useful product. Below a pH of about 10.5, the bleach component is not stable and ultimately decomposes. A pH above about 13.0 renders the compositions too alkaline for widespread consumer use. A preferred pH for the compositions of this invention is about 11.5. The re quired pH range can be achieved through addition of a strong base such as potassium hydroxide, lithium hydroxide, or preferably, sodium hydroxide.

The compositions disclosed herein can be prepared by physically intermixing the various components; it is convenient and desirable to start with readily available household bleach which is generally an aqueous solution of about 5.25% sodium hypochlorite, adjust the pH, and add the other components. However, it has been discovered that particularly desirable results are achieved, both in the area of bleach-brightener compatibility and in general physical stability of the system, when the components of the composition are combined in accordance with a certain preferred method. This method comprises the prior combination of the optical brightener and stabilizing agent before addition thereof to a hypochlorite-containing solution. Such a combination of optical brightener and stabilizing agent can be prepared, for example, by the addition of the optical brightener to an aqueous suspension of stabilizing agent with gentle heating (40 95 C.) and stirring.

Many of the polymeric materials useful herein as stabilizing agents are commercially available in latex form, i.e., an aqueous suspension containing about 20% to of the polymeric solids, and are generally referred to as emulsion polymers or, more generically they are referred to as latex. This physical form of the stabilizing agent is very convenient and preferable for use in preparing the compositions of the invention.

Thus, a preferred composition is prepared "by mixing about 1-2 parts (solid basis) of a latex stabilizing agent of about 40% solids with about 0.02 to about 0.1 part of a bleach-compatible optical brightener and adding this mixture to about 98 parts of an aqueous, pH-adjusted, hypochlorite solution. Alternatively, the pH of the brightener-stabilizing agent mixture can be properly adjusted before addition thereof to a hypochlorite solution. The precise method of adjusting the pH is not critical so long as the final composition, which contains both bleach and optical brightener, has a pH within the required range.

Still another method of preparing the herein disclosed compositions is to pass chlorine gas through 1.5 normal sodium hydroxide whereby an aqueous solution of pH 11.0 to 11.5 and containing 5 to 6% sodium hypochlorite is readily for-med. To this solution is added additional sodium hydroxide, optical brightener and stabilizing agent, either separately or combined. It is recognized that a solution prepared in this manner contains sodium chloride in an amount approximately equimolar to the amount of sodium hypochlorite present. Indeed, generally available household bleach containing 5.25% sodium hypochlorite also contains about 4 to 5% sodium chloride. However, the presence of sodium chloride in the compositions of this invention is not undesirable. In fact, a moderate amount, i.e., less than about 10%, of a strong salt such as sodium chloride is believed to advantageously affect the solubility characteristics of the optical brightener.

The compositions of this invention can be added to a detergent-containing, or a detergent-free medium, e.g., water, whereby desired bleaching and optical brightening effects upon textiles immersed in said medium are readily achieved.

The following examples are illustrative of the invention but are not intended to be limiting. All percentages and ratios herein and in the appended claims are by weight unless indicated otherwise.

In each example, unless otherwise so indicated, the concentration of hypochlorite was measured iodometrically; the optical brightener effectiveness was assessed by washing textiles, i.e., a white cotton terry wash cloth (11.5" x 11.5") and a piece of white cotton print cloth (5" x 7.5"), for 10 minutes in 16 liters of 140 F. tap Water containing 0.15% of a brightener-free, bleach-free detergent composition consisting of a blend of 9.5% sodium tallow alkyl sulfate, 7.8% sodium linear dodecyl benzene sulfonate, 2.0% coconut ammonia amide, 49.4% sodium tripolyphosphate, 15.0% sodium sulfate, 5.9% sodium silicate, 0.3% carboxymethyl cellulose, and 10.1% water; and containing ml. of the test composition containing an optical brightener and hypochlorite bleach; rinsing in cold tap water, air drying, and recording the fluorescent intensity of the print cloth as measured with a Galvanek-Morrison Fluorimeter wherein an increase in GM units indicates an increase in optical brightener efliciency.

EXAMPLE I In a 50 ml. flask, 15.0 g. of stabilizing agent suspension and 0.060 g. of optical brightener were combined by magnetically stirring and heating at about -90 '(i. for about 30 minutes. The stabilizing agent suspension was a polystyrene-type latex (an aqueous emulsion containing about 40% of a copolymer of styrene, methyl acrylate, and acrylic acid, with a ratio of about 1.7 methyl acrylate units and about 1 acrylic acid unit per 16 styrene units, and having a mean particle diameter of about 0.1/ 4 and a molecular weight of about 1,000,000); the optical brightener was sodium 4-(2'H-5'-su'lfonaphtho[1,2'-d] trioazol 2-yl)-2-cyanostilbene. This mixture was then added to 600 ml. of a commercially available household bleach (consisting of about 5.25% sodium hypochlorite, about 4-5% sodium chloride, balance water) in which 0.6 g. of sodium hydroxide had been previously dissolved. Mixing was achieved by pouring back and forth between beakers. This composition was opaque and had a pH of 11.3. The optical brightener 'was uniformly suspended throughout the composition as determined by visual examination under ultraviolet light.

Bleach-brightener compatibility (stability) over an extended period of time for the composition of this example is illustrated by the following data.

Time Milliequivalents of Fluorescence (Days after preparation) hypochlorite/ml. in of Textile composition (GM units) In this example, other optical brighteners such as sodium 4 (4'H acenaphtho[4',5-d]triazol 2"-yl)-2- stilbenesulfonate, 4- (2'H-naphtho[ 1,2-d] triazol-Z-yl) -2- stilbenesulfon-N,N-bis(2" hydroxyethyl)amide, disodium 4,4-bis(2H naphtho[1",2"-d]triazol-2"-yl)-2,2'- stilbenedisulfonate, disodium-3,7-bis(4' 'rnethoxybenzamido)2,S-disulfodibenzothiophene-S,5 dioxide, can be readily substituted for the sodium-4-(2'H-5'-sul-fonaphtho [l',2'-d]triazol-2"-yl)-2-cyanostilbene without altering the advantageous properties of the composition.

EXAMPLE II In a 50 ml. flask, 15.0 g. of stabilizing agent suspension and 0.300 g. of optical brightener were combined by magnetically stirring and heating at about 60-70" C. for about minutes. The stabilizing agent suspension was a polystyrene-type latex (an aqueous emulsion containing about 40% of a copolymer of styrene and methyl acrylate with a ratio of about 1 methyl acrylate unit to about 6 styrene units, and having a mean particle diameter of about 0.2 and a molecular weight of about 1,000,000); the optical brightener was sodium 4-(2'-H-naphtho[l,2- d]triazol-2"-yl)-2-stilbenesulfonate. This mixture was then added to 600 ml. of a commercially available household bleach (consisting of about 5.25% sodium hypochlorite, 45% sodium chloride, balance Water) in which 0.6 g. of sodium hydroxide had been previously dissolved. The entire mixture was then agitated in a conventional laboratory blender for five minutes. The resulting composition was stable, opaque and had a pH of 11.4. Visual examination under ultraviolet light revealed that the optical brightener was uniformly suspended throughout the composition. The fluorescence conferred on cotton by this composition was 135 GM units immediately after mixing and was 115 GM units after the composition had been stored for seven days.

In this example, other optical brighteners such as 1,2- bis[1 (2" hydroxyethyl -vbenzimidazol 2 yl]ethylene, 4,4 bis[l (2"' hydroxyethyl)benzimidazol- 2"-yl]stilbene, and 1-(2'-hydroxyethyl)-2-styrylbenzimidazole, can be readily substituted for the sodium 4-(2-H- naphtho[ 1',2'-d] triazol-2"-yl-2 stilbenesulfonate without altering the advantageous properties of the composition.

EXAMPLE III In a conventional laboratory blender, 10.0 g. of stabilizing agent (dry basis) was agitated for five minutes with 100 ml. of water and 0.100 g. of optical brightener. The stabilizing agent was colloidal silica (the silica had a mean particle diameter of about 0.015,u.); the optical brightener was sodium 4-(2'H-naphtho[1',2'-d]triazol- 2"-yl)-2-stilbenesulfonate. This mixture was then added to 1000 m1. of a commercially available household bleach (consisting of about 5.25% sodium hypochlorite, about 4-5% sodium chloride, balance water) and mixed by gentle stirring. The composition had a pH of 10.8 and the optical brightener was uniformly suspended therein as was determined by visual examination in both natural and ultraviolet light.

Bleach-brightener compatibility (stability) over an extended period of time for the composition of this example is illustrated by the following data.

Time Milliequivalents of Fluorescence (Days after preparation) hypochlorite/ml. in of Textile composition (GM units) In this example, other optical brighteners such as 2,5- bis[1' (2" hydroxyethyl)benzimidazol 2 yl]thi0- phene, 2,5 bis[1' (2" hydroxylethyl)benzimidazol- 2' yl]furan, 4,4 bis(benzoxazol 2" yl)stilbene, 1,2- bis(5' methylbenzoxazol 2' yl)ethylene, 2,5 bis(benzoxazol 2' yl)thiophene, 2 styrylnaphtho[1',2 d] oxazole, 2,5 bis(benzoxazol 2 yl)furan, 1 (benzimidazol 2 yl) 2 (benzoxazol 2" yl)ethylene, 4 [1" (2" hydroxylethyl)benzimidazol 2" yl)- 4'-bcnzoxazol-2-yl)stilbene, can readily be substituted for the sodium 4-(2H-naphtho[1,2'-d]triazol-2-yl)-2- stilbenesulfonate without altering the advantageous properties of the composition.

EXAMPLE IV The procedure described in Example III was used to combine 10.0 g. of a polyethylene stabilizing agent suspension (an emulsion polymerized ethylene latex having a mean particle diameter of 25p. and a molecular weight of about 20,000), 0.100 g. of sodium 4-(2H-naphtho[l', 2 dltriazol 2" yl) 2 stilbenesulfonate optical brightener, 100 ml. of water, and 1000 ml. of a commercially available household bleach (consisting of about 5.25% sodium hypochlorite, 45% sodium chloride, balance Water). The optical brightener was uniformly suspended in this composition which had a pH of 11.2.

Bleach-brightener compatibility (stability) over an extended period of time for the composition of this example is indicated by the following data.

Milliequivalents of Fluorescence hypochlorite/ml. in of Textile composition (GM units) In this example, other optical brighteners such as 2- (5' phenylbenzoxazol 2 yl) 5 phenylthiophene, and sulfonated 4 (5" phenylbenzoxazol 2" yl) 4'- stilbenecarboxylic acid, can be readily substituted for the sodium 4 (2H naphtho[l',2' d]triazol 2" yl) 2- stilbenesulfonate without altering the advantageous properties of the composition.

Also in this example the following polymeric stabilizing agents can be substituted for the polyethylene stabilizing agent of the example without altering the advantageous properties of the composition:

(A) Polystyrene, mean particle diameter of 0.0l,u, molecular weight of 10,000;

(B) Oxidized polystyrene having an acid number of 30, mean particle diameter of 0.05 molecular weight of 50,000;

(C) Sulfonated polystyrene having an acid number of 20, mean particle diameter of 0.811., molecular weight of 100,000;

(D) Oxidized polyethylene having an acid number of 20, mean particle diameter of 1.0,u, molecular weight of 200,000;

(E) Sulfonated polyethylene having an acid number of 15, mean particle diameter of 3.011., molecular weight of 400,000;

(F) Polypropylene, mean particle diameter of 5.0,, molecular weight of 500,000;

(G) Oxidized polypropylene having an acid number of 20, mean particle diameter of 7.0,u, molecular weight of 700,000;

(H) Sulfonated polypropylene having an acid number of about 15, mean particle diameter of 10.0;t, molecular weight of 800,000;

(I) Copolymer of styrene with maleic anhydride, mean particle diameter of 15.0].L, molecular weight of 900,000;

(I) Copolymer of styrene with acrylonitrile, mean particle diameter of 20.0;t, molecular weight of 1,000,000;

(K) Copolymer of styrene with methacrylic acid, mean particle diameter of 25.0 t, molecular weight of 2,000,000;

(L) Copolymer of styrene with ethyl methacrylate, mean particle diameter of 300 molecular weight of 3,000,000.

The following examples (Examples V through IX) represent additional specific embodiments of the invention. The compositions in these examples are prepared in the same manner as the composition of Example I, the optical brightener is sodium 4-(2H-naphtho[1',2-d]triazol-2"- yl)-2-stilbenesulfonate. Each composition is stable, and exhibits both bleaching and optical brightening eifects on desired textiles when added to a laundry solution, e.g., water.

What is claimed is:

1. A stable aqueous composition having a pH ranging from about 10.5 to about 13.0 consisting essentially of water and (A) from about 1.0% to about 10% alkali metal hyp'o chlorite bleach;

(B) from about 0.002% to about 2.0% hypochlorite bleach-compatible optical brightener characterized by insolubility of more than 99% in a solution of about 5% alkali metal hypochlorite and insolubility of less than 25% in a solution of about 0.02% alkali metal hypochlorite; and

(C) from about 0. 1% to about 2.0% of a particulate,

hypochlorite bleach-stable, brightener-stable, insoluble and dispersible stabilizing agent.

2. The composition of claim 1 wherein said optical brightener is selected from the group consisting of stilbylmonotriazoles, dibenzothiophenedioxides, 1,2-bis(imidazolyl) ethylenes, 2-aryl-5-oxazolylthiophenes and sul- Stabilizing Agent Optical Bleach, Percent Brightener, by Weight pH Percent by Weight V Copolymer of 10 moles of styrene with 1 mole of ethyl acrylate having a mean particle diameter of 0.002 KOO], 1.0 10. 5

0.05 and a molecular weight of 500,000, 0.1 percent by weight. VI Copolymer of 40 moles of styrene with 1 mole of methyl maleate having a mean particle diameter 0. 01 LiOCl, 3.0 11. 5

of 0.3;. and a molecular weight of 2,000,000, 0.5 percent by weight. VII Copolymer of 25 moles of styrene with 1 mole of maleic acid having a mean particle diameter 010.2 0. 10 N aOCl, 8.0. 12. 0

and a molecular weight of 1,500,000, 1.0 percent by weight. VIII--. Copolymer 01' 30 moles of styrene with 1 mole of ethyl maleate and 2 moles of fumaric acid having a 1. 0 LiOCl, 10.0. 12. 5

mean particle diameter of 0.1]; and a molecular weight of 800,000, 1.5 percent by weight. IX Copolymer of 4 moles of styrene with 1 mole of vinyl acetate having a mean particle diameter of 1p. 2. 0 N aOCl, 5.0. 13. 0

and a molecular weight of 700,000, 2.0 percent by weight.

EXAMPLE X In a ml. flask, 20.0 g. of stabilizing agent suspension and 0.080 g. of optical brightener were combined by magnetically stirring and heating at about 90 C. for about 30 minutes. The stabilizing agent suspension was a polystyrene-type latex obtained from Morton Chemical Company under the designation of E290DL (an aqueous emulsion containing about 40% of a copolymer of styrene, methyl acrylate, and acrylic acid, with a ratio of about 1.7 methyl acrylate units and about 1 acrylic acid unit per 16 styrene units, and having a mean particle diameter of about 0.1, and a molecular weight of about 1,000,000; the optical brightener was sodium 4-(2'H-naphtho[1,2'-d] triazol-2"-yl)-2-stilbenesulfonate. This mixture was then admixed with 800 ml. of a commercially available household bleach (consisting of about 5.25% sodium hypochlorite, about 45% sodium chloride, balance water) in which 0.8 g. of sodium hydroxide had been previously dissolved. This composition was opaque and had a pH of 11.6. The optical brightener was uniformly suspended throughout the composition as determined by visual examination under ultraviolet light.

Bleach-brightener compatibility (stability) over an extended period of time for the composition of this example is indicated by the following data.

fonated derivatives the-reef, and l-imidazolyl-Z-oxazolylethylenes.

3. The composition of claim 1 wherein said stabilizing agent is colloidal silica having a mean particle diameter ranging from about 0.01 to about 0.05

4. The composition of claim 1 wherein said stabilizing agent is a polymeric material having a mean particle diameter ranging from about 0.01 to about 30 and having a molecular weight ranging from about 10,000 to about 3,000,000.

5. The method of preparing the composition of claim 1 which comprises:

(A) admixing the hypochlorite bleach-compatible optical brightener and stabilizing agent; and

(B) adding the mixture thus formed to an aqueous alkali metal hypochlorite bleach solution.

6. A stable aqueous composition having a pH ranging from about 10.5 to about 13.0, and consisting essentially of water and (A) from about 3% -to about 7% alkali metal hypochlorite bleach wherein the alkali metal is selected from the group consisting of lithium, sodium and potassium;

('B) from about 0.01% to about 0.1% bleach-compatible optical brightener selected from the group consisting of sodium 4(2'H-naphtho[1,2-d] tria- 13 zol-2"-yl)-2-stilbenesulfonate, sodium 4-'(2'H-5-sulfonaphtho[1,'2'-d]triazol-2"-yl)-2-cyanostilbene, disodi-um 3,7-bis(4-methoxybenzamido)-'2,8-disulfodibenzothiophene-5,5-dioxide, 1,'2-bis[1-(2"-hydroxyethyl) benzimidaZol-2-yl] ethylene, monosulfonated 2-(5-phenylbenz-oxazo1-2'-yl) 5 phenylthiophene; and 1-(benzimidazol-2'-yl) 2 (benzoxazol-2"-yl) ethylene;

(C) from about 0.1% to about 2.0% of a particulate,

hypochlorite bleach-stable, brightener-stable, insoluble and dispersible stabilizing agent.

7. The composition of claim 6 wherein said stabilizing agent is a polymeric material having a mean particle diameter ranging from about 0.01 to about 30 1. and a molecular Weight ranging from about 10,000 to about 3,000,000, said polymeric material being selected from the group consisting of polystyrene, polyethylene, polypropylene, and oxidized polystyrene having an acid number of from about to about 40, oxidized polyethylene having an acid number of from about 10 to about 30, oxidized polypropylene having an acid number of from about 10 to about 30, sulfona-ted polystyrene having an acid number of from about 10 to about 30, sulfonated polyethylene having an acid number of from about 5 to about and sulfonated polypropylene having an acid number of from about 5 to about 25.

8. The composition of claim 6 wherein said stabilizing agent is a polymeric material having a mean particle diameter ranging from about 0.01 to about p. and a molecular weight ranging from about 10,000 to about 3,000,000, said polymeric material being a copolymer of styrene with a monomer selected from the group consisting of malei-c anhydried, acrylonitrile, methacrylic acid and ethyl methacrylate, said copolymer having a ratio of 1 monomer unit per each 4 to 40 styrene units.

9. The composition of claim 6 wherein said stabilizing agent is a polymeric material having a mean particle diameter ranging from about 0.05 to about 110 and a molecular weight ranging from about 500,000 to about 2,000,- 000, said polymeric material being a copolymer of styrene with monomers selected from the group consisting of methyl acrylate, ethyl acrylate, methyl maleate, ethyl maleate, vinyl acetate, acrylic acid, maleic acid, fumaric acid, and mixtures thereof, said copolymer having a ratio of 1 monomer unit per each 4 to 40 styrene units.

10. The composition of claim 6 wherein said stabilizing agent consists of from about 0.5% to about 1.5% colloidal silica having a mean particle diameter ranging from about 0.01; to about 0.05

11. An opaque stable aqueous composition having a pH range from about 10.5 to about 13.0 consisting essentially of water and ("'A) from about 3% to about 7% sodium hypochlorite;

(B) from about 0.01% to about 0.1% uniformly suspended bleach-compatible optical brightener comprising a stilbylmonotriazole selected from the group consisting of sodium 4- 2H-5-sulfonaphtho [1,2- d]-triazol-2"-yl) -2-cyanostilbene, and 4-(2'H-naphtho [1',2-d]triazol-2"-yl) -2-stilbenesulfonate;

(C) from about 0.5% to about 1.5% stabilizing agent consisting of a copolymer of styrene with a monomer selected from the group consisting of methyl acrylate, ethyl acrylate, methyl maleate, ethyl maleate, vinyl acetate, acrylic acid, maleic acid, fumaric acid, and mixtures thereof; said copolymer having a ratio of 1 monomer unit per each 4 to 40 styrene units, a mean particle diameter ranging from about 0.05 2 to about 1.0,!1. and a molecular weight ranging from 5 00,000 to about 2,000,000.

12. The composition of claim 11 wherein said stabilizing agent is a copolymer of styrene and methyl acrylate with a ratio of 1 methyl acrylate unit to about 6 styrene units, and having a mean particle diameter of about 02 and a molecular weight of about 1,000,000.

13. The composition of claim 11 wherein said stabilizing agent is a copolymer of styrene, methyl acrylate and acrylic acid with a ratio of 1.7 methyl acrylate units and 1 acrylic acid unit per about 16 styrene units, and having a means particle diameter of about 01 1 and a molecular weight of about 1,000,000.

References Cited UNITED STATES PATENTS 2,643,197 6/1953 Savidge et al. 25289.0 2,676,982 4/ 1954 Freyermuta et al. 252-94 X 2,715,632 8/1955 Sartori 25289 2,765,239 10/ 1956 Siegrist 2.. 252-8'9 2,674,604 4/1954 Hoefle et al 25294 X 3,101,333 8/1963 Adams et al. 2'52-94 X 3,133,916 5/1964 Duennenbegcr et a1. 252-94 X 3,154,494 10/1966 Speak et a1 25299 X 3,177,207 4/1965 Leverkusen et al. 252-89 3,222,371 12/1965 Buell et al. 25294 X FOREIGN PATENTS 560,574 7/1958 Canada.

LEON D. ROSDOL, Primary Examiner.

M. WEINBLATT, Examiner.