US3655566A - Bleach having stable brighteners - Google Patents

Abstract

Liquid household bleach composition containing optical brighteners protectively carried in the bleach solution against chemical deterioration by a finely particulate sequentially prepared synthetic organic polymer which is dispersed through the bleach solution.

Description

United States Patent Robinson et al. [451 Apr. 11, 1972 [54] BLEACH HAVING STABLE [56] References Cited I T BR GH ENERS UNIT ED STATES PATENTS [72] Inventors: Ronald A. Robinson, Garden Grove;

3,393,153 7/1968 Zrmmerer et al. ..252/95 33 9 3,544,500 12/1970 Osmond et al ...252/316 x 3,401,123 9/1968 Brynko et a1. 1 ..252/316 [73] Assignee: Purex Corporation, Ltd., Lakewood, Cal f 3,213,053 10/1965 Kendrick ..1 17/ 100 A [22] Filed: 1970 Primary Examiner-Mayer Weinblatt [21] Appl. No.: 16,927 Att0rneyWhite, Haefliger and Bachand 52 us. 01 ..252/95, 252/187, 252/316, 1 [57] ABSIRACT 7 117/100 A Liquid household bleach composition containing optical [51] Int. Cl. ..Clld 7/54 brighteners protectively carried in the bleach solution against [58] Field of Search ..252/95, 187, 316; 1 17/ 100 A chemical deterioration by a finely particulate sequentially prepared synthetic organic polymer which is dispersed through the bleach solution.

12 Claims, No Drawings BLEACH HAVING STABLE BRIGHTENERS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention has to do with liquid household bleach generally used for whitening of fabrics in conjunction with detergents. Specifically, the invention is concerned with improvements in conventional bleaches in both appearance and usefulness.

2. Prior Art It is the function of a liquid household bleach to remove colored impurities from fabrics by chemical conversion, e.g. into colorless products as by oxidation. Alternatively blueing" of fabrics renders invisible undesired color by color compensation.

It is currently popular to brighten fabrics beyond whitening them. This is today accomplished through the use of particular dyes, termed optical brighteners, in detergents. Similar to blueing, optical brighteners compensate for a yellow cast in a fabric occasioned by absorption of the short wavelength light by the fabric. Compensation is by way of partial replacement of the absorbed or lost" light so that the eye sees a complete white without loss of light. Optical brighteners introduce additional light through fluorescence, that is, they absorb the invisible ultraviolet portion of the daylight spectrum and convert the energy there into visible light. Optical brightening thus effectively adds light to fabrics.

As stated, presently the mode of transferring optical brightener to fabric is by addition to wash water of the brightening compounds in admixture with the detergent. Use of brightening compounds in bleach rather than detergent has been retarded by the known propensity of bleach to oxidize and destroy most such compounds.

Bleach and detergent are used together in washing white fabrics. It has been found that the bleach will destroy most optical brighteners present in commercial detergents as well so that the net whitening-brightening effect of the bleach and optical brightener is not strictly additive.

Optical brighteners and nearly all dyes are sensitive to the chemical action of bleach. It has been proposed e.g. by Zimmerer in US. Pat. No. 3,393,153 issued July 16, 1968, to mix brighteners with preformed polymers, therein termed stabilizing agents, and by heating the mixture to so associate the brightener and polymer that the stability of the latter will somehow accrue to the benefit of the former. It would appear that the bleach could have destructive access to any brightener combined with the polymer particles in this manner and that benefits in brightener stability would be marginal and evanescent.

SUMMARY OF THE INVENTION It is a major objective of the present invention to provide both stable brightening and whitening in fabric washing opera tions. Another objective is to provide a new source of optical brighteners for washing solutions. A further objective is to provide optical brighteners in a form in which they are unreduced in effectiveness by the conjoint presence of bleach. It is stillanother objective to provide increased substantivity of optical brightener to fabrics.

These and other objectives of the invention, to be made apparent as the description proceeds, are realized through the provision .of a liquid household bleach composition comprising an aqueous solution of a bleaching agent and an optical brightener in an effective amount, said brightener being protectively carried in the bleach solution by a specially sequentially formed finely particulate synthetic organic polymer which is dispersed through the bleaching agent solution.

Specifically the invention provides an optically brightened liquid bleach composition comprising an aqueous solution of a bleaching agent and an optical brightener in an effective amount. The brightener is protectively carried in the bleach solution by a finely particulate synthetic organic polymer carrier which is dispersed through the solution e.g. in amounts between 0.05 and 5 percent by weight based on the total weight of the composition. The carrier comprises polymer particles typically between 0.5 and 2 microns in average particle size and having an inner portion consisting essentially of the optical brightener compound and a styrene-acrylic polymer and an outer portion forming an encapsulating layer over the inner portion and consisting essentially of styrene polymer free of the brightening compound, the particles comprising per 100 parts by weight of polymer from 65 to 98 parts of a styrene monomer having eight to 12 carbon atoms and conversely from two to 35 pans of methacrylic or acrylic acid monomer copolymerized therewith, the inner portion polymer containing a major proportion but less than percent by weight of the styrene and at least a major weight proportion of the acid monomer, with the outer portion of the particle polymer containing the balance of these monomers. From 0.5 to 25 and preferably from five to 10 parts per 100 parts by weight of the polymer, of a hydrophilic comonomer may be employed in replacement of a like amount of styrene monomer, e.g. monomer selected from the hydroxyester, ether, amide and cyano derivatives of acrylic or methacrylic and or a vinyl sulfonate monomer having the formula RCH= CH-SO3Me in which R is hydrogen or an aromatic or alkyl radical having up to 10 carbon atoms and Me is an alkali metal.

The particles typically contain from 0.5 to 5 percent by weight of the optical brightening compound, based on the weight of the styrene in the polymer. The optical brightening compound may be selected from derivatives of 4,4- diaminostilbene-2, 2-disulfonic acid, dibenzothiophene-5,5- dioxide, azole, coumarin, pyrazine and 4-aminonaphthalimides. The polymer particles thus distributed in bleach have been found to be highly substantive to fabric to carry the optical brightener through the wash cycle onto the fabric where it remains to give an appearance of brightness to the fabric. The aqueous solution of bleaching agent typically has a pH of at least 10 and may include as the bleaching agent typically a hypochlorite ion generating compound such as those generally used for bleaching e.g. a heterocyclic N-chlorimide or sodium hypochlorite, and the like, in amounts between 1 and 10 percent by weight.

The invention further provides a method of adding optical brighteners to a highly alkaline hypochlorite ion-containing solution which includes incorporating a brightener in the inner portion of a two layer synthetic organic polymer particle and thereafter adding the carrier to the solution. The brightener may be so incorporated by emulsion preparing the polymer in the intimate presence of the brightener dissolved in the styrene monomer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The liquid household bleach opacified in accordance with this invention may be any hypochlorite ion containing solution containing sufiicient free alkali to have a pH of 10 and preferably 11.5 and higher, typically from 0.1 to 1.0 percent by weight free alkali. Per cent concentrations of hypochlorite ion will range between 1 and 10 per cent by weight with a practical minimum being 2.5 percent. Most bleaches contain between 3 and 7 percent hypochlorite ion, and this concentration is most suited to use in the invention. As mentioned above, various bleaching agents may be used including the heterocyclic N-chlorimides such as trichlorocyanuric acid, dichlorocyanuric acid and salts thereof such as the alkali metal salts e.g. sodium and potassium dichlorocyanurates. Other irnides are hypochlorite ion-generating also in aqueous solution and may be used e.g. N-chlorosuccinimide, N- chloromalonimide, N-chlorphthalimide and N- chloronaphthalimide. Other materials are the hydantoins e.g. the l,3-dichloro-5,5-dimethyl hydantoin, N-monochloro-C, C-dirnethylhydantoin, methylene bis (N-chloro-C, C- dimethylhydantoin), 1 ,3-dichloro-5 -methyl-5-isobutyldimethylhydantoin, l,3-dichloro-5-methyl-5-ethylhydantoin,

1,3-dichloro-5-methyl- Sn-amylhydantoin and the like as well as trichloromelamine. Preferred sources of hypochlorite ion are the water soluble inorganic salts such as lithium, calcium, potassium and, particularly, sodium hypochlorite.

The insoluble synthetic organic polymer component of the present composition is of a particle size and constitution permitting suspension in the aqueous hypochlorite ion solution. Particle size on average will generally range between 0.01 and 5 microns and preferably 0.5 and 2 microns. Concentrations of the polymer particles will range from an effective amount for imparting added brightness through deposition onto fabric of the contained optical brightener to that amount forming a deposit visible as such on fabric. Convenient concentrations in the bleach solution are between 0.05 and 5 per cent by weight, with 0.3 to 3 per cent by weight being particularly preferred.

Preferred polymer particles will exhibit an index of refraction more than 0.05 unit greater than the index of the aqueous, e.g. hypochlorite ion solution. As such, the polymer particles are perceptible as a component of the composition although not individually visible, i.e. an opacity is imparted to the bleach composition.

The safe incorporation of optical brighteners and other dyes in aqueous bleach according to the invention is realized by combining the optical brightener compound in a polymer in a manner to insulate the brighteners from the harsh environment while permitting its useful brightening function. To so combine the brightener compound with polymer, the brightener is first dissolved in the oil-soluble monomer of the polymer and the monomer-brightener solution is copolymerized with vinyl acid, i.e. acrylic or methacrylic acid which has been previously dissolved in water, by conventional emulsion polymerization techniques. Subsequently a second emulsion polymerization is effected to coat the particles resulting from the first polymerization with a bleach impervious polymer free of brightener thus to protect the brightener compound in the first or inner center portion of the polymer particle. While the emulsion recipies are conventional, the sequence of operations is not conventional and enables the realization of the invention.

It is known to emulsion polymerize styrene and acrylic acid by dissolving an emulsifying agent in all the water and adding the acrylic acid and possibly a hydrophilic comonomer. Styrene or other oil soluble, principal monomer is added to the mixture and stirred to achieve emulsification. The temperature of the emulsion is raised to 120-l40 F. and a persulfate or peroxide catalyst is added with or without a reducing agent to form a redox couple to produce free radicals to initiate the polymerization reaction. The temperature of the emulsion rises exothermically as the monomer species are converted into polymer. Usually no external heat is required and almost all of the monomer is polymerized to provide a milky aqueous suspension of particles (a latex) in which the particles typically range from 0.5 to 2 microns in average particle size and contain about 30 to 60 percent of the total polymer.

In preparing compositions according to the present invention, the above common procedure is modified to achieve the purposes of the invention. Thus only a portion of the monomer components are first reacted together. And the brightener is first dissolved in the oil-soluble monomer (styrene) to assure intimate incorporation of the brightener compound in the polymer. In a second stage of the preparation the balance of the monomers is added and after sufficient intermixing and addition of catalyst, a second emulsion polymerization is effected to overcoat the first formed particles with additional, separately formed polymer which it has been found will protect the brightener in the first stage polymer.

While not wishing to be bound to any particular theory of operation it is believed the remarkable stability of the brightening compound in the bleach compositions of the invention against oxidative attack may derive from the formation of micelles upon the addition of the emulsifier-surfactant to water. The micelles are lamellar colloidal particles having structures dependent on the hydrophobic/hydrophilic orientation of the surfactant molecule. Upon the addition of the hydrophobic (styrene) monomer containing dissolved dye in the first stage of preparation, these monomer droplets and hydrophilic monomer become encapsulated in the micelles. Addition of catalyst causes polymerizaion to proceed within the confines of the micelle until a hard, discrete particle of polymer is formed, still enveloped by the micelle structure. Upon the addition of the second portion of the hydrophobic (styrene) monomer, in the absence of additional surfactant for formation of new micelles, the added monomer enters the previously formed polymer particle micelles and forms a layer of reactive monomer over the outside of the polymer particles. With the addition of more catalyst, this newly added monomer polymerizes and forms a shell of basically hydrophobic polymer over the inner particle portion containing the brightener compound. This shell prevents chemically active molecules such as oxidizing molecules of bleach from entering the particle to the brightener compound. The second added portion of hydrophobic monomer may contain brightener compound, but such compound in theouter layer of the particles is readily destroyed in contact with bleach.

The particulate polymer in which the brightener compound protectively inheres consists essentially of a styrene monomer, acrylic or methacrylic acid and optionally a second hydrophilic comonomer.

As the hydrophobic monomer component there may be employed styrene per se, i.e. vinyl benzene, or a substituted styrene such as vinyl toluene or butyl styrene, i.e. alkyl substituted styrenes in which the alkyl groups contain from one to four carbon atoms such that the styrene monomer contains from eight to 12 carbon atoms, inclusive. Or the styrene monomer may be monohalogen ring substituted such as chlorostyrene or bromostyrene. The acid component may be described generically as a water-soluble a, B ethylenically unsaturated monocarboxylic acid, i.e. vinyl acid having three to four carbon atoms namely acrylic or methacrylic acids. The proportion by weight of combined styrene monomer and acid monomer in the particulate polymer ranges between 65 to 98 parts styrene and two to 35 parts of the vinyl acid per 100 parts by weight of the terpolymer.

Polymerization is carried out as hereinafter described to provide polymer particles ranging in size between 0.01 and 5 microns and preferably between 0.5 and 2 microns where an opacifying effect is desired. It is often desirable to incorporate a further monomer in the polymer. This additional monomer will be a hydrophylic monomer such as a derivative of methacrylic or acrylic acid containing up to 10 carbon atoms and free of carboxyl groups. Thus, such derivatives as the ester, hydroxyester, ether, amide or cyano derivatives of acrylic or methacrylic acids may be used in amounts of between 0.5 and 25 and preferably five and 10 parts by weight, in substitution for an equal weight amount of the styrene monomer, per 100 parts of the final opacifying polymer. A water-soluble vinyl sulfonate monomer may be the additional hydrophilic component, e.g. having the formula R-CH CHSO Me in which R is a hydrocarbon radical free of aliphatic unsaturation having up to 10 carbon atoms, e.g. an aromatic radical such as tolyl, benzyl or phenyl radical; an alkyl radical such as methyl, ethyl, propyl, butyl, isobutyl, pentyl, neopentyl, hexyl, heptyl, octyl, 2-ethyl hexyl, nonyl and decyl, or hydrogen and Me is an alkali metal, e.g. sodium, potassium, lithium and cesium. Specific termonomers of choice include the hydroxyalkyl esters of methacrylic acid in which the alkyl group contains from one to four carbon atoms and particularly hydroxyethyl and hydroxypropyl methacrylate, and acrylamide, methacrylamide, acrylonitrile, methyl vinyl ether, sodium or potassium vinyl sulfonate and styrene sulfonate.

The monomers just described are emulsion polymerized using conventional catalysts, oxidizers or reducers, temperatures and pressures but with the critical steps of first dissolving the brightener compound in the styrene monomer and dissolving the water-soluble vinyl acid and hydrophilic comonomer, if used, in water, suitably with the emulsifying surfactant, prior to addition of the styrene. Apart from the herein discussed sequential reactant additions, the preparation of the polymers is carried out as for any other exothermic emulsion polymerization in each stage. Thus an aqueous solution of a suitable surfactant is mixed with the water soluble vinyl acid. Thereafter the water-soluble styrene reactant into which the brightener compound has been previously dissolved, suitably at concentrations between 0.5 and 5 percent based on the total of styrene in the polymer and preferably at least 1 percent by weight, same basis, is mixed in and agitated until emulsified as the oil phase. The emulsion is then maintained at an elevated temperature through exothermic and/or added heat if necessary in admixture with a suitable catalyst, e.g. and preferably water-soluble persulfates such as ammonium and sodium and potassium persulfate and peroxides, e.g. hydrogen peroxide; and also catalysts such as t-butyl perbenzoate and tbutyl hydroperoxide, as well as other oil-soluble materials such as bisazobutyronitrile and cumene hydroperoxide. Following reaction for the required period and at temperatures between l30200 F. and boiling the reaction mixture is cooled and neutralized with alkali. The latex may be spray or otherwise dried without loss of dispersibility or stability in liquid household bleach.

In the preparation of brightener protective polymer particles for use in the present invention, the hydrophobic monomer, e.g. styrene is divided into two portions for separate, sequenced emulsion polymerizations. The first portion, for the first emulsion polymerization comprises a major weight proportion, but less than all of the styrene to be used in fonning the polymer, i.e. at least 50 percent by weight of the 65 to 98 parts by weight of styrene ultimately to be used per 100 parts of polymer is employed in the first polymerization. All of the optical brightener to be incorporated in the polymer is dissolved in this first portion of styrene. As indicated elsewhere this will be from 0.5 to 5 percent by weight of brightener compound based on the total weight of styrene monomer in the polymer. Preferably at least 1 percent by weight of brightener is dissolved in the first styrene portion. The first styrene portion will generally be less than 90 percent by weight of the total polymer styrene content and will typically be between 60 and 80 percent by weight of the polymer total styrene content.

The acrylic or methacrylic acid comonomer may also be divided into two portions for sequential polymerization. The first portion employed in the first polymerization, will be a major weight proportion of the acid in the total polymer, i.e. at least 50 percent by weight of total polymer acid. This first portion may range up to 100 percent by weight of the total polymer portion of acrylic or methacrylic acid,.but typically from 60 to 80 percent of the total polymer acid will be included in the first acid portion.

As mentioned above from 0.5 to 25 and preferably from five to parts by weight of the styrene monomer may be replaced on a weight for weight basis by certain hydrophilic comonomers. This substitution may be made in either the first or second styrene monomer portion, and preferably from 60 to 80 percent by weight of the added hydrophilic comonomer is incorporated in the first styrene portion.

The balance of each monomer comprises a second portion for use in the second emulsion polymerization.

With the monomers having been thus divided for two polymerizations, the optical brightener is dissolved in the styrene monomer first portion. The acid first portion is dissolved in water and the two solutions are mixed together in a suitable vessel. The mixture is emulsion polymerized by the conventional'techniques above described by adding a surfactant, a polymerization catalyst and heating. Heating is initially to about 130 F. but the temperature rises with the reaction exotherm to about 190 F. or somewhat higher or lower. The first reaction product is a latex of styrene-acid polymer (or terpolymer with the hydrophilic comonomer) having from 30 to 60 percent by weight of polymer present as particles suspended in and aqueous medium.

The reaction product is cooled before the next stage of polymerization. Cooling typically will be to less than F., or the reaction initiation temperature of the second polymerization mixture. The reaction mixture is prepared by adding the balance of each of the monomers to the cooled first polymerization reaction product. The mixture is mixed together and permitted to stand from 15 to 30 minutes or longer. Thereupon additional polymerization catalyst is added and the temperature of the reaction mixture permitted to rise above 130 F. to F. or higher or lower, with the reaction exotherm. Reaction is continued to produce a latex containing polymer particles having an average particle size between 0.5 and 2 microns. The optical brightener is within these particles and protectively carried there. Suitable surfactants for efi'ecting emulsion polymerization as described and/or for suspending the finely particulate polymer in bleach or other aqueous liquid are the noncationic types, i.e. anionic, nonionic or amphoteric. Various of these surfactants will show greater or less tolerance for the harsh environment of liquid household bleach, depending on the concentration and pH thereof.

Among suitable surfactants are anionic aromatic compounds, e. g. water-soluble higher alkyl aryl sulfonates particularly those having from eight to about 15 carbon atoms in the alkyl group. It is preferred to use the higher alkyl benzene sulfonates, although other mononuclear aryl nuclei, such as toluene, xylene, or phenol, may be used also. The higher alkyl substituent on the aromatic nucleus may be branched or straight chained in structure, examples of such group being nonyl,dodecyl and pentadecyl groups derived from polymers of lower mono-olefins, decyl, keryl, and the like.

Illustrative of suitable aliphatic anionic compounds are the normal and secondary higher alkyl sulfates, particularly those having about eight to 15 carbons in the fatty alcohol residue, such as lauryl (or coconut fatty alcohol) sulfate. Other suitable members of this class are the sulfuric acid esters of polyhydric alcohols incompletely esterified with higher fatty acids; the oleic acid ester of isethionic acid; the higher fatty acids (e.g. coconut) ethanolamide sulfates; the higher fatty acid amides of amino alkyl sulfonic acids, e.g. laun'c acid amide of taurine; and the like.

These sulfates and sulfonates are used in the form of their water-soluble salts, such as the alkali metal and nitrogen-containing, e.g. lower alkylolamine, salts. Examples are the sodium, potassium, ammonium, isopropanolamine, mono-and triethanolamine salts of said higher alkyl benzene sulfonate, higher alkyl sulfate and the like.

Typical specific examples are:

the sodium salt of a sulfate ester of an alkylphenoxypoly (ethyleneoxy) ethanol, the ammonium salt of this sulfate ester, sodium methyl oleyl taurate, sodium alkyl naphthalene sulfonate, alkyl aryl sodium sulfonate, sodium tetraphydronaphthalene sulfonate, sodium alkyl aryl sulfonate, alkyl amido sulfate, cocomonoglyceride sulfate, dodecylbenzene sodium sulfonate, dodecylbenzene sulfonic acid, tridecylbenzene sodium sulfonate, fatty alcohol sodium sulfate, sodium dodecyl diphenyl oxide disulfonate, sulfonated castor oil, polyethoxyalkyl phenol sulfonate triethanolamine salts, sodium triethanolamine alkyl aryl sulfonate, magnesium lauryl sulfate, potassium lauryl sulfate, sodium lauryl ether sulfate, ammonium lauryl ether sulfate, sodium tallow sulfate, dodecylbenzene sodium sulfonate, oleyl methyl tauride, ammonium lauryl sulfate, amide sulfonate, and the like.

In general, suitable nonionic surfactants include those such as produced by the introduction of alkylene oxide group into an organic hydrophobic compound or group having an aliphatic or aromatic structure. The hydrophobic organic group generally contains at least eight carbon atoms and up to about 30 carbon atoms. Condensed with the hydrophobic group are at least five and preferably up to about 50 alkylene oxide groups. It is preferred to use the polyoxyethylene condensates derived from ethylene oxide. It is preferred to use the polyalkylene oxide condensates of alkyl phenol, such as the polyoxyethylene ethers of alkyl phenols having an alkyl group of at least about six, and usually about eight to 12 carbons, and preferably eight to nine carbon atoms, and an ethylene oxide ratio (No. of moles per phenol) of about 7.5, 8.5, 11.5 or 20, though the number of ethylene oxide groups will be usually from about eight to 40. The alkyl substituent on the aromatic nucleus may be di-isobutylene, diamyl, polmerized propylene, dimerized C -C olefin, and the like.

Further suitable nonionics are the polyoxyalkylene esters of organic acids, such as the higher fatty acids, rosin acids, tall oil acids, or acids from the oxidation of petroleum, et cetera. These polyglycol esters will contain usually from about 12 to about 30 moles of ethylene oxide or its equivalent and about eight to 22 carbons in the aryl group. Suitable products are refined tall oil condensed with 16 or 20 ethylene oxide groups, or similar polyglycol esters of lauric, stearic, oleic acids, etc.

Additional nonionic agents are the polyalkylene oxide condensates with higher fatty acid amides, such as the higher fatty acid primary amides, monoand diethanolamides. Suitable agents are coconut fatty acid amide condensed with about to 50 moles of ethylene oxide. The fatty acyl group will have similarly about eight to 22 carbons, and usually about 10 to 18 carbon atoms, in such products. The corresponding sulfonamides may be used also if desired.

Other suitable polyether nonionics are the polyalkylene oxide ethers of high aliphatic alcohols. Suitable fatty alcohols having a hydrophobic character, preferably eight to 22 carbons, are lauryl, myristyl, cetyl, stearyl and oleyl alcohols which may be condensed with an appropriate amount of ethylene oxide, such as at least about 6, and preferably about 10 to 30 moles. A typical product is oleyl alcohol condensed with about l2, or moles of ethylene oxide. The corresponding higher alkyl mercaptans or thioalcohols condensed with ethylene oxide are suitable in the present invention also. The water-soluble polyoxyethylene condensates with hydrophobic polyoxypropylene glycols may be employed also, e.g. the ethylene oxide condensates with condensates of propylene oxide and propylene glycol.

Further suitable nonionic materials are the higher fatty acid alkanolamides, such as the monoethanolamides, diethanolamides and isopropanolamides wherein the aryl radical has about 10 to 14 carbon atoms and amine oxides. Examples are coconut (or equivalent lauric), capric and myristic diethanolamide, onoethanolamide and isopropanolamide, dodecyl dimethyl amine oxide and dimethyl acetoxyalkylamine oxide where alkyl is C C Generally, these surfactants comprise from 0.05 to 10 per cent by weight, and preferably from 0.5 to 3 percent of the reaction mixture and the latex added to the liquid household bleach. Desirably the bleach composition has a surface tension of 45 dynes/centimeter or less by virtue of the pressure of the surfactant.

The optical brighteners useful herein include that species of dyes which are fluorescing compounds, generally optically colorless and nonabsorptive in the visible portion of the spectrum. Generally, suitable brighteners are aromatic or heterocyclic compounds having a series of conjugated double bonds.

Primary among typical compounds useful herein are:

l. The derivatives of 4,4'-diaminostilbene-2,2 disulfonic acid, particularly the bistriazinyl, bisacyl and mixed acyl triazinyl derivatives. Napthotriazolylstilbene sulfonic acid may be mentioned. Azinyl radicals may be substituted on the carbons of the heterocyclic ring with many radicals including hydroxy, amino, alkoxy, hydrocyalkoxy, chloro, thio, alkoxybenzoyl, anilino, morpholino and others. Acyl radicals include acetyl, phenoxyacetyl, alkoxybenzoyl toluyl, benzoyl and aminobenzoyl. Benzoyl acyl radicals are generally substituted in the ortho and/or para position, eg with p-acetamino, methyl, methoxy, acetoxy, 2-hydroxyethoxy, haloalkoxy or alkenyloxy groups. The sulfonic acid group substituent in the stilbene may be replaced with an electron donor radical such as alkyl, alkoxy or sulfamyl;

11. The derivatives of dibenzothiophene-S, S-dioxide, specifically 3,7diaminodibenzothiophene 2,8-disulfonic acid- 5, 5-dioxide in which the preferred acyl groups are alkoxybenzoyl groups. See, e.g. US. Pat. Nos. 2,563,795; 2,573,652; 2,702,759; 2,719,155; and 2,733,165 which are incorporated herein by reference; and

III. The azoles, prepared generally by diazotization of 4- aminostilbene-2-sulfonic acid, coupling with an orthocoupling naphthylamine derivative (or benzene or a heterocylic) and oxidation to the triazole. See US. Pat. Nos. 2,784,197; 2,713,057; 2,817,665; 2,784,184; 2,972,611; 2,640,056; 2,639,990; Brit. Pat. No. 808,113; Belg. Pat. No. 572,498; US. Pat. Nos. 2,765,304; 2,765,239; and Ger. Pat. No. 735,478, which are incorporated herein by reference; e.g. naphthotriazole, bis-benzimidazolyl compounds and benzimidazole;

IV. Coumarin and derivatives;

V. Pyrazine and derivatives; and

VI. 4Aminonaphthalimide.

In addition, dyes and pigments may be used in place of or with the foregoing, e.g. chromates, polysulfides, thianaphthanones and phthalocyanine such as potassium dichromate, Ultramarine blue, Sulfanthrene Pink FFD Paste and Monastral Fast Green GWD, for the purpose of contributing blue light of various tints. As used herein the term optical brightener compound" is intended to be inclusive of these colorants as well as the fluorescing, colorless dyes.

The invention is illustrated by the following examples, in which all parts and percentages are by weight.

EXAMPLE 1 A. Polymer Preparation Dissolve five parts of dioctyl ester of sodium sulfosuccinic acid and 2 parts of tetrasodium N-( l,2-dicarboxyethyl)-N-octadecyl-sulfosuccinamate in 700 parts of water. To this add 50 parts of methacrylic acid followed by 30 parts of a 25 percent aqueous solution of sodium vinyl sulfonate. Dissolve five parts of Calcofluor ALF (optical brightener compound) in 250 parts of styrene. Emulsify the styrene solution in the aqueous phase and carry out the polymerization by heating the emulsion to F. and adding one part of sodium persulfate catalyst. The temperature rises to about -200 F. from the exothermic heat of reaction. Cool to 130 F. and add 30 parts of a 25 percent aqueous solution of sodium vinyl sulfonate followed by 250 parts of styrene. Stir for 30 minutes holding at 130 F. and then add catalyst and polymerize the second monomer addition with the heat of the exotherm and cool.

B. Bleach Composition Preparation Add 0.5 percent of the latex obtained in Part A to a 5 percent aqueous solution of sodium hypochlorite.

C. Stability Fluorescence is evaluated at periodic intervals. The bleach shows fluorescence initially and for 3 months of 70 F., the normal shelf life for hypoehlorite bleach. Fabric washed with the bleach shows greater whitening (brightening) both on visual and instrumental inspection.

EXAMPLE 2 Duplicate Example 1 but employ 300 parts of vinyl toluene in the first polymerization reaction mixture and 200 parts thereof in the second polymerization reaction mixture, in place of the styrene in Example 1. In Part C, evaluation of fluorescence shows continuing fluorescence after 3 months at 70 F.

EXAMPLE 3 Duplicate Example 1 but employ 30 parts of acrylic acid in the first polymerization reaction mixture and 20 parts in the second polymerization reaction mixture. The brightener containing latex is stable in 6 percent sodium hypochlorite bleach by fluorescence testing 9 CONTROL 1 Duplicate Example 1 but mix the methacrylic acid first with styrene and then add to the aqueous surfactant solution, followed by heating to polymerize. In parts B and C the emulsion which had similar size particles and the same milky appearance prior to addition to the bleach as the Example emulsion, shows immediate physical deterioration and quickly demulsifies and settles as a flocculated mass in the holding vessel.

We claim:

1. Optically brightened liquid bleach composition consisting essentially of an aqueous solution of a hypochlorite ion generating bleaching agent and an optical brightener compound in an effective amount, said brightener compound being protectively carried in said solution by a finely particulate styrene polymer carrier which is dispersed through said solution and comprises particles having an inner portion consisting essentially of said optical brightener compound and a styrene-acrylic polymer formed by polymerization of styrene in which said compound has been predissolved, with an acrylic monomer and an outer portion forming an encapsulating layer over the inner portion and consisting essentially of styrene polymer free of said compound, said particle comprising per 100 parts of polymer from 65 to 98 parts of a styrene monomer selected from the group consisting of styrene and alkyl substituted styrene in which the alkyl group contains from one to four carbon atoms and conversely from two to 35 parts of methacrylic or acrylic acid monomer copolymerized therewith, said inner portion polymer containing a major proportion but less than 90 percent by weight of said styrene and at least a major weight proportion of said acid monomer, said outer portion polymer containing the balance of said monomers.

2. Composition according to claim 1 in which said particles contain from 0.5 to 5 percent by weight of said compound based on the weight of the styrene in said polymer.

3. The composition according to claim 1 in which said carrier is substantive to fabric.

4. The composition according to claim 1 in which said hypochlorite ion generating compound is a heterocyclic N- chlorimide.

5. The composition according to claim 1 in which said hypochlorite ion generating compound is sodium hypochlorite.

6. The composition according to claim 1 in which said styrene monomer is vinyl benzene.

7. The composition according to claim 1 in which said carrier is present in said solution in an amount between 0.05 and 5 percent by weight.

8. Composition according to claim 1 in which said particles have an average particle size between 0.5 and 2 microns.

9. Composition according to claim 1 in which said particles comprise per 100 parts from 88 to 92 parts of styrene monomer and from eight to 12 parts of methacrylic or acrylic acid.

10. Composition according to claim 1 in which said inner portion contains from 60 to weight percent of said styrene and from 50 to weight percent of said acid.

11. The composition according to claim 5 in which said solution has a pH of at least 10.

12. The composition according to claim 11 in which the hypochlorite ion is present in an amount between 1 and 10 percent by weight.

Claims (11)

1. 2. Composition according to claim 1 in which said particles contain from 0.5 to 5 percent by weight of said compound based on the weight of the styrene in said polymer.
2. 3. The composition according to claim 1 in which said carrier is substantive to fabric.
3. 4. The composition according to claim 1 in which said hypochlorite ion generating compound is a heterocyclic N-chlorimide.
4. 5. The composition according to claim 1 in which said hypochlorite ion generating compound is sodium hypochlorite.
5. 6. The composition according to claim 1 in which said styrene monomer is vinyl benzene.
6. 7. The composition according to claim 1 in which said carrier is present in said solution in an amount between 0.05 and 5 percent by weight.
7. 8. Composition according to claim 1 in which said particles have an average particle size between 0.5 and 2 microns.
8. 9. Composition according to claim 1 in which said particles comprise per 100 parts from 88 to 92 parts of styrene monomer and from eight to 12 parts of methacrylic or acrylic acid.
9. 10. Composition according to claim 1 in which said inner portion contains from 60 to 80 weight percent of said styrene and from 50 to 100 weight percent of said acid.
10. 11. The composition according to claim 5 in which said solution has a pH of at least 10.
11. 12. The composition according to claim 11 in which the hypochlorite ion is present in an amount between 1 and 10 percent by weight.