CA1307714C - Liquid detergent containing perborate bleach - Google Patents

Abstract

Liquid Detergent Containing Perborate Bleach Abstract Liquid detergent compositions comprising a perborate bleach are disclosed. The perborate bleach is present as small particles suspended in an aqueous liquid medium.
The small perborate particles are formed by in situ recrystallization.

Description

Liquid Detergent Containing Perborate Bleach J. Geudens T.Y. Yap Technical Field The present inuention relates to aqueous liquid detergent compositions which contain perborate bleach in the form of small particles, i.e., particles hauing a number auerage particle diameter of from 0.5 to 20 micrometers. The small particles are formed by in-situ recrystallization, preferably of perborate monohydrate.

Background So-called hea~y duty liquid detergent compositions as are commercially auailable at present typically do not contain a bleach. Dissolued peroxygen compounds, like hydrogen peroxide, interact with other components generally used in liquid detergents, like enzymes and perfumes.

Insoluble peroxygen bleach compounds present the problem of poor physical stability of suspensions made therewith.

DE-OS 35 11 515, published October 17, 1985, discloses non-aqueous liquid detergent compositions comprising sodiumperborate monohydrate and an actiuator for the perborate. FR 2,579.615, published October 3, 1986, discloses similar non-aqueous compositions which further comprise catalase inhibitors. The compositions exemplified in these two patents do not contain anionic surfactants.

J. Dugua and B. Simon, "Crystallization of Sodium Perborate from ~queous Solutions", Journal of Crystal Growth 44 (1978), 265-286, discusses the role of surfactants on the nucleation and crystal growth of sodium perborate tetrahydrate.

It is an object of the present inuention to prouide aqueous liquid detergent compositions containing perborate particles hauing a number auerage particle diameter of from 0.5 micrometer to 20 micrometers. It is a further object of this inuention to prouide a process by which particles in the desired particle size range are formed in situ Summary of the Inuention The aqueous liquid detergent compositions of the present inuention haue a pH of at least 8, comprise at least 5X of an organic non-soap anionic surfactant at least 5X of a builder, and from 1% to 40X, preferably from 10~ to 20~ of a perborate bleach in the form of particles hauing a number auerage particle diameter of from 0.5 micrometer to 20 micrometers, said particles hauing been formed by in situ recrystallization. Preferably, the perborate particles are formed by in situ recrystallization of a perborate monohydrate, e.g. sodium perborate monohydrate.

Preferred liquid detergent compositions further comprise from 5X to ~OX of a water-miscible organic soluent. The preferred water-miscible organic soluents are the low molecular weight monohydric alcohols; the most preferred of these soluents is ethanol.

Preferred herein are detergent compositions hauing a pH of at least 9, more preferably at least 9.5.

Detailed Description of the Inuention . _ The present inuention addresses the problem of formulating an aqueous liquid detergent composition ha~ing suspended therein small particles of a perborate bleach.
For reasons of physical stability it is necessary that the perborate particles haue a number auerage particle diameter of from 0.5 to 20 micrometers. It is not advisable to ~.ake such small particles by e.g., grinding, because this process is not very attractive economically.
Moreover, such small particles in a dry state would pose serious industrial hygiene and safety problems.
It has also been found that detergent compositions containing small perborate particles that are obtained by grinding have poorer physical stability than composi-tions containing perborate particles of the same diameter that were obtained by ln situ crystallization. Although this phenomenon is not fully understood, it is speculated that particle shape plays a role in it.
It has now been discouered that the required small perborate particles can be formed by in situ recrystallization in the presence of at least 5~ of an organic, non-soap, anionic surfactant and at least 5~ of a detergent builder.

Percentages as used herein are percentages by weight of the liquid detergent composition. ~eight percentages of the perborate are calculated as perborate monohydrate, euen through the particles may be different in composition (e.g., the tetrahydrate).

~ he term "in situ recrystallization" relates to processes whereby perborate particles are formed from larger particles in the presence of the water/anionic surfactant/detergent builder matrix. This term therefore encompasses processes inuoluing chemical reactions, as when sodium perborate is formed by reacting stoichiometric amounts of hydrogen peroxide and sodium metaborate and borax. It also encompasses processes involving dissolution and recrystallization, as in the dissolution of perborate monohydrate and subsequent formation of perborate tetrahydrate. Recrystallization may also take place by allowing perborate monohydrate to take up crystal water, whereby the monohydrate directly recrystallizes into the tetraborate, without the dissolution step.
In one embodiment of the invention, a perborate compound, e.g., sodium perborate tetrahydrate or sodium perborate monohydrate, is added to an aqueous liquid comprising the anionic surfactant and the detergent builder The resulting slurry is stirred. During this stirring the perborate compound undergoes a process of dissolution/recrystallization. Due to the presence of the anionic surfactant and the detergent builder this dissolution/recrystallization process results in particles ha~ing the desired particle diameter.

~s the monohydrate is more susceptible to recrystallization, ~he monohydrate is preferred for this embodiment of the inuention. Particle diameters herein are number average particle diameters, unless otherwise specified. For reasons of physical stability it is preferred that the particle size distribution is relatively narrow; i.e., it is preferred that less than 10% of the perborate be present in the form of particles having a diameter greater than 25 micrometers, more preferably less than 10% (wt) has a particle diameter greater than 10 micrometers.
In a second embodiment of the invention the perborate compounds is formed in situ by chemical reaction. For example, sodium metaborate is added to an aqueous liquid comprising the anionic surfactant and the detergent builder. Then a stoichiometric amount of hydrogen peroxide is added while stirring. Stirring is continued until the chemical reaction is complete.

-- Inste~d of metabcrJte, other borat~ compounts, lncludlng, ~9., borax and borlc acld, may be slJbstltuted. If borax is used as the boron conlpound, ~ stolchiometrlc amount of a base, e.g., sodium hydroxlde, ls add~d to cnsure reactlon of the borax to ~taborats. Ths process then proceeds ~s descrlbed herelnabove for metabor~t~ converslon. Instead of hydrogen p~roxld~, other p~r~x-ldes may b~ use~ (~.g., sodlum peroxlde), ~s known ln the ~rt.
Nor~lly, p~rbor~te tetr~hydr~t~ lS formed. At temperatures ~bov~ ~bout ~0 deg. C th1s m~y slow1y conv~rt to the thermody-n~mlc~l1y more st-ble trlhydrate. rhls conversion may ltself be used to m~ke sm~ll partlcles of tr~hydr~te out of l~rg~ partleles of tetrahydr-te, Preferred liquid detergent compositions contain, in addition to water, a water-miscible organic soluent. The soluent reduces the solubility of perborate in the liquid phase and thereby enhances the chemical stability of the composition.

It is not necessary that the organic soluent be fully miscible with water, prouided that enough of the soluent mixes with the water of the composition to affect the solubility of the perborate compound in the liquid phase.

The water-miscible organic soluent must, or course, be compatible with the perborate compound at the pH that is used. Therefore, polyalcohols hauing uicinal hydroxy groups (e.g. 1,2-propanediol and glycerol) are less desirable.

Examples of suitable water-miscible organic solvents include the lower aliphatic monoalcohols, and ethers of diethylene glycol and lower monoaliphatic monoalcohols.
Preferred soluents are ethanol, iso-propanol, l-methoxy 2-propanol and butyldiglycolether.

Although the presence or absence of other ingredients plays a role, the amount of auailable oxygen in solution is largely determined by the ratio water : organic -- 6a -soluent. The smaller this ratio (i.e. the more organic soluent is used in the sol~ent system), the lower the amount of a~ailable oxygen in solution. ~lthough this is good for stability of the bleach system, it is less desirable for a good solubility of other components (e.g.
electrolyte, anionic surfactants).

- In pr~ctlc~l t~rm~, th~ r~tlo w~ter org~nlc ~olvent ls, ~or most systems, ln the r~n~e from 8 1 to I 3, prefQr~bly fro~ 5 1 to l 2 In c~lcul~tlng th~ ~mount of w~ter ln the deterg~nt composl tlon, ~llow~nces should be m~de for w~ter rsle~sed 1n or taken up by chQmlcal ~nd phys k-l process~s that m~y take pl~c- durlng the pr~paratlon of the detergent composltlon For ex~mple, water may b~ form~d ln the neutr~llz~tlon of ~n anlonlc surf~ctant, ~here~s water m~y b~ t~k~n up ln the converslon of met~borat~ to perborate t~tr~hydr-t~, a~ wQll as ln th~ conv~rslon of perbor~te mono-hydrats to perbor~te t~tr~hydr~te W~t~r is ~lso pres~nt ln most detergent r~w ~terl~ls, and should be t~k~n ~nto ~ccount ~ s it is belieued that the ionic strength of the composition affects the dissolution/recrystallization process, preferred compositions ha~e an ionic strength of at least 0.-~ moles/liter, preferably from 2 to 3.5 moles/liter. Ionic:strengths are calcu].ated on the assumption that all ionic material other than perborate present in the composition are fully dissociated.

Ionic strengths are calculated on the assumption that all ionic materials present in She composition are fully dissociated.

The liquid detergent compositions herein contain from 5X to 60X of the liquid detergent composition, preferably from lSX to 40X, of an organic surface-acti~e agent selected from nonionic, anionic, and zwitterionic surface-acti~e agents and mixtures thereof. ~t least S~
of the detergent composition must be anionic surfactant.

Synthetic anionic surfactants can be represented by the general formula R SO M wherein Rl represents a hydrocarbon group selected from the group consisting of straight or branched alkyl radicals containing from about 8 to about 24 carbon atoms and alkyl phenyl radicals containing from about 9 to about 15 carbon atoms in the alkyl group. M is a salt forming cation which typically is selected from the group consisting of sodium, potassium, ammonium and mixtures thereof.

~ preferred synthetic anionic surfactant is a water-soluble salt of an alkylbenzene sulfonic acid containing from 9 to 15 carbon atoms in the alkyl group.
~nother preferred synthetic anionic surfactant is a water-soluble salt of an alkyl sulfate or an alkyl polyethoxylate ether sulfate wherein the alkyl group contains from about 8 to about 24, preferably from about 10 to about 18 carbon atoms and there are from O to about 20, preferably from O to about 12 ethoxy groups. Other suitable anionic surfactants are disclosed in U.S. Patent 4,170,565, Flesher et al., issued October 9, 1979.

The nonionic surfactants are conuentionally produced by condensing ethylene oxide with a hydrocarbon hauing a reactiue hydrogen atom, e.g., a hydroxyl, carboxyl, or amido group, in the presence of an acidic or basic catalyst, and include compounds hauing the general formula R~CH2CH20)nH wherein R represents the hydrophobic moiety, ~ represents the group carrying the reactiue hydrogen atom and n represents the auerage number of ethylene oxide moieties. R typically contains from about 8 to 22 carbon atoms. They can also be formed by the condensation of propylene oxide with a lower molecular weight compound. n usually uaries from about 2 to about 24.

The hydrophobic roiety of the nonionic compound is preferably a primary cr secondary, straight or branched, aliphatic alcohol hauing from about 8 to about 24, preferably from about 12 to about 20 carbon atoms. ~ more complete disclosure of suitable nonionic surfactants can be found in U.S. Patent 4,111,855. Mixtures of nonionic surfactants can be desirable.

Zwitterionic surfactants include deriuatiues of aliphatic quaternary ammonoum, phosphonium, and sulphonium compounds in which the aliphatic moiety can be straight or branched chain and wherein one of the aliphatic substituents contains from about 8 to about 24 carbon atoms and another substituent contains, at least, an anionic water-solubilizing group. Particularly preferred zwitterionic materials are the ethoxylated ammonium sulfonates and sulfates disclosed in U.S. Patents 3,925,262, Laughlin et al., issued December 9, 1975 and 3,929,678, Laughlin et al., issued December 30, 1975.

Semi-polar nonionic surfactants include water-soluble amine oxides containing one alkyl or hydroxy alkyl moiety of from about 8 to about 28 carbon atoms and two moieties selected from the group consisting of alkyl groups and hydroxy alkyl groups, containing from 1 to about 3 carbon atoms which can optionally be joined into ring structures.

Suitable anionic synthetic surface-actiue salts are selected from the group of sulfonates and sulfates. The like anionic detergents are well-known in the detergent arts and haue found wide-spread application tn commercial detergents. Preferred anionic synthetic water-soluble sulfonate or sulfate salts haue in their molecular structure an alkyl radical containing from about 8 to about 22 carbon atoms.

_ 9 ~ xamples of such preferred anionic surfactant salts are the reaction products obtained by sulfating C~-C18 fatty alcohols deriued from tallow and coconut oil;
alkylbenzene sulfonates wherein the alkyl group contains from about 9 to about 15 carbon atoms; sodium alkylglyceryl ether sulfonates; ether sulfates of fatty alcohols deriued from tallow and coconut oils; coconut fatty acid monoglyceride sulfates and sulfonates; and water-soluble salts of paraffin sulfonates hauing from about 8 to about 22 carbon atoms in the alkyl chain.
Sulfonated olefin surfactants as more fully described in e.g. U.S. Patent Specification 3,332,880 can also be used. The neutralizing cation for the anionic sunthetic sulfonates and/or sulfates is represented by conuentional cations which are wibely used in detergent technology such as sodium and potassium.

A particularly preferred anionic synthetic surfactant component herein is represented by the water-soluble salts of an alkylbenzene sulfonic acid, preferably sodium alkylbenzene sulfonic acid, preferably sodium alkylbenzene sulfonates ha~ing from about 10 to 13 carbon atoms in the alkyl group.

A preferred class of nonionic ethoxylates is represented by the condensation product of a fatty alcohol hauing from 12 to 15 carbon atoms and from about 4 to 10 moles of ethylene oxide per mole of fatty alcohol.
Suitable species of this class of ethoxylates include :
the condensation product of C12-C15 oxo-alcohols and 7 or 9 moles of ethylene oxide per mole of alcohol; the condensation product of narrow cut C14-C15 oxo-alcohols and 7 or 9 moles of ethylene oxide per mole of fatty(oxo)alcohol; the condensation product of a narrow cut C12-C13 fatty(oxo)alcohol and 6,5 moles of ethylene oxide per mole of fatty alcohol; and the condensation products of a C1O-Cl4 coconut fatty alcohol with a degree of ethoxylation (moles E0/mole fatty alcohol) in the range from 5 to 8. The fatty oxo alcohols while mainly linear can haue, depending upon the processing conditions and raw material olefins, a certain degree of branching, particularly short chain such as methyl branching.

~ degree of branching in the range from 15% to 50X
(weight%) is frequently found in commercial oxo alcohols.

Preferred nonionic ethoxylated tomponents can also be represented by a mixture of 2 separately ethoxylated nonionic surfactants hauing a different degree of ethoxylation. For example, the nonionic ethoxylate surfactant containing from 3 to 7 moles of ethylene oxide per mole of hydrophobic moiety and a second ethoxylated species hauing from 8 to 14 moles of ethylene oxide per mole of hydrophobic moiety. ~ preferred nonionic ethoxylated mixture contains a lower ethoxylate which is the condensation product of a C12-C15 oxo-alcohol, with up to 50~ (wt) branching, and from about 3 to 7 moles of ethylene oxide per mole of fatty oxo-alcohol, and a higher ethoxylate which is the condensation product of a C16-C19 oxo-alcohol with more than 50X (wt) branching and from about 8 to 14 moles of ethylene oxide per mole of branched oxo-alcohol.

The liquid detergent.compositions herein optionally contain a fatty acid component. Preferred saturated fatty acids haue from 10 to 16, more preferably 12 to 14 carbon atoms. Preferred unsaturated fatty acids are oleic acid and palmitoleic acid.

Detergent enzymes can be used in the liquid detergent compositions of this inuention. In fact, one of the desirable features of the present compositions is that they are compatible with such detergent enzymes. Suitable enzymes include the detergent proteases, amylases, lipases and cellulases. Enzymatic stabilizing agents for use in aqueous liquid detergents are well known. Preferred herein is a salt of formic acid, e.g., sodium formate.
The amount of this stabilizing agent typically ranges from 0.5X to 2~.

Preferred compositions contain an inorganic or organic builder. Examples of inorganic builders include the phosphorous-based builders, e.g., sodium tripolyphosphate, sodium pyrophosphate, and aluminosilicates (zeolites).

Examples of organic builders are represented by polyacids such as citric acid, nitrilotriacetic acid, and mixtures of tartrate monosuccinate with tartrate discuccinate. `Preferred builders for use herein are citric acid and alk(en)yl-substituted succinic acid compounds, wherein alk(en)yl contains from 10 to 16 carbon atoms. ~n example of this group of compounds is dodecenyl succinic acid. Polymeric carboxylate builders inclusiue of polyacrylates, polyhydroxy acrylates and polyacrylates/polymaleates copolymers can also be used.

The compositions herein can contain a series of further optional ingredients whlch are mostly used in additiue leuels, usually below about 5X. Examples of the like additiues include : polyacids, enzymes and enzymatic stabili2ing agents, suds regulants, opcifiers, agents to improue the machine compatibility in relation to enamel-coated surfaces, bactericides, dyes, perfumes, brighteners and the like.

The liquid compositions hercin ean contain further additiues of a leuel from 0 05 to 2X

~ hese additiues include polya~inocarboxylates such as ethylenediaminotetracetic cid, diethylenetriaminopentacetic acid, ethylenediamino disuccinic acid or the water-solu~le alkali metal salts thereof Other additi~es include organo-phosphonic acids;
particularly preferred are ethylenedi-mino tetramethylenephosphonic acid, hexamethylened~amino tetramethylenephosphonic acid, diethylenetriamino pentamethylenephosphonic acid nd minotrimethyleneDhosphonic cid ~ he compo~lt10ns m~ further cont~1n ble-ch st~bi112~rs o~
the k1nds known 1n th- rt tf ~ pr~c~s lnvolvln~ ths us~ of hydrogcn peroxlde 1s used for the pr~p~r~t10n of th~ u1d tot-rsent typlc-l bl~ch st~bll k~rs m-y bc pr~s-nt ~s 1ntroducsa - wlth the commerc~ v~ bls hydro4cn ~crox1dc ~x~pl~s of su1t~bl- ble~ch st~b111~rs lnclud- scorb1c ~c1d dlp1c311nlc ~c1d sodlum st~nn~tss nd 8 hydroxyquln~lln~ c-n ~150 be lncludct 1n thsss co~po~lt10ns ~t lsv~ls b~t~een 0 0l nd l%

The beneficial utilization of the claimed compositions under uarious u--ge conditions can require the utilization of a suds regulant ~hile generally all detergent suds regulants can be utilized preferred for use herein are alkylated polysiloxanes such as dimethylpolysiloxane also frequently termed silicones The silicones are frequently used in a leuel not exceeding 1 5X, most preferably between O 1X and 1 OX

It can also be desirable to utilize opacifiers inasmuch as they contribute to create a uniform appearance of the concentrated liquid detergent compositions Examples of suitable opacifiers include polystyrene commercially known as LYTRON 621 manufactured by MONS~N~O
A CHEMIC~L CORPOR~TION. The opacifiers are frequently used in an amount from 0 3X to 1 5X
* Trade-mark . .

The liquid detergent compositions of this in~ention further can comprise an agent to improue the washing machine comp~tibility, particularly in relation to enamel-coated surfaces.

- It can further be desirable to add from O.lX to 5X of known antiredepositlon and/or compatibilizing agents.
~xamples of the like additi~es include : sodium carboxymethylcellulose; hydroxy-Cl 6-alkylcellulose;
polycarboxylic homo- or copolymeric ingredients, such as :
polymaleic acid, a copolymer of maleic anhydride and methyluinylether in a molar ratio of 2:l to l:2; and a copolymer of an ethylenically unsaturated monocarboxylic acid monomer, hauing not more than S, preferably 3 or 4 carbon atoms, for example (methy)-acrylic acid, and an ethylenically unsaturated dicarboxylic acid monomer hauing not more than 6, preferably 4 carbon atoms, whereby the molar ratio of the monomers is in the range from 1:4 to 4:l, said copolymer being described in more detail in Canadian Patent 1,187,373, issued May 21, 1985.

The following examples illustrate the inuention and facilitates lts understanding.

Liquid detergent compositions are prepared by mixing the listed ingredients in the stated proportions :

Inqredients Composition (weiqht X) I II III IU U
-Water 33 32 26 23 34 Ethanol 14 15 18 22 11 Linear dodecylbenzene sulfonic acid 12 10 8 8 12 Condensation product of 1 mole of C13-Cl5 oxo alcohol and 7 moles of ethylene oxide 7 9 10 8 7 Sodium cocoyl sulfate 2 3 4 2 2 Dodecenyl succinic acid 13 10 12 15 13 Citric acid 0.8 1 1 0.8 0.8 Oleic acid 3.3 4 3 2 3.3 Protease 0.3 0.5 - 0.5 Diethylenetria~ine pentamethylene phosphonic acid 0.05 0.85 0.05 0.05 0.05 Sodium formate 0.9 Sodium perborate monohydrate 10 10 12 10 10~) Sodium hydroxide (to adjust to) pH 9 10 9 11 8.2 Perfume, minors ~ ----balance ------------*) sodium perborate tPtr~h~r~t~

The sodium perborate compound is added after all the other ingredients have been mixed. The composition is stirred ouernight.
The resulting recrystallized perborate particles haue a number auerage particle diameter of about 7 micrometers.

The following compositions are prepared in the same manner.

Inqredients ComPosition (wei~ht Xl UI VII UIII IX X

Water 28 Z7 32 28 22 Ethanol - 7 5 7 8 1-Methoxy-2-propanol 14 3.5 - 7 7 Isopropanol Butyldiglycolether - 4.0 5 Linear dodecylbenzene sulfonic acid 12 7 13 10 9 Nonionic surfactant 7 11 3.5 8 7 Sodium cocosulfate 2.5 2.5 3.0 3.0 2.0 TMS/TDS* - - - 6.5 3.5 Dodecenyl succinic acid 9 - - 8.5 9.5 Tetradecenylsuccinic acid 4 - - - 1.0 Coconut fatty acid - 16 1.0 Oleic acid 3.6 4.0 2.0 2.0 2.5 Citric acid 0.9 0.5 - - 0.5 DTPMP~*~ 0.5 0.5 - 0.8 1.5 Ethylene diamine tetra-acetic acid - - 1.0 Sodium tripolyphosphate - - 15.0 Sodium perborate tetra-hydrate Sodium perborate monohydrate . 10.4 9 13 13 19 Sodium formate 0.8 1.0 1.0 0.5 1.0 Protease 0.6 0.8 0.5 0.5 0.6 Sodium hydroxide to pH 10 11 11 10.5 10.5 Perfume, minors ~ --balance------~-------* 80:20 mixture of tartrate monosuccinate and tartrate dis~l~c~inatP
** Diethyleretr~amino pentamethylene phosphonic acid - 15a -:5llU!Lrl5L ComDo~ition t~ei~ht W~ter 31 2 Ethonol 6 S 6 l-Methoxy-2~prop-nol _ -IsoproP~nol 6,5 6 ~utyld~glycol~ther ~ _ _ _ _ _ Linear dodccylbenzene sulfon~c acid Nonionic ~urfact~nt 7,2 Sodlum eocosulf~to 3.1 ~ 0 TMS/TD8~
Dodecenyl cuccinic ~cid 13,~ 7 tetr~decenyl~ucclnlc aeid _ _ Coconut f~tty acld - 1 0 Ol~ic cld 3,~ 3,0 Citrlc aeld ~,~ 3 5 . _,._____ .. . . .... . .. . _ DrPMPa~ q o ~,1 Ethyl~n~ diamlne t~tr--at~tlt ~ctd ~
80dium tripolypho~ph~to _ _ ~odium perbor~o t-tra-_ Sodlum parboratë monohydrat~ 9,0 _ ~ ' Sodlum form~te 2 q 1 Protea~e 0,7 ~,o Sodlum hydroxlde to pH 9 ~,5-P~rf~mC, minor~ lancc---Slmllar compos1tlons are prepared s follows.
A llquld detergent matrlx 15 prepared by mlxlng water, the organlc solvont(s), the surfsctant~s), and the bullder materlal(s). The matrlx ls tr~mmed wlth sodlum hydroxide to a pH
of 8.5-9. M~taborate powder ls addod under stlrrlng. A mllky suspenslon ls obtalned. Then hydrogen peroxlde ls added as an aqueous solutlon. Small crystals of perborate tetrahydrate are formed. TYP1CB11Y, the perborate tetrahydrate cr~stals have a welght average partlcle slze of about 4 mlcrometers. As a resu1t of the exother~1c react10n the temperature r1ses to, typlc~lly, abo~t 40 deg. C. The detergent composltlon 1s cooled to about 25 deg. C prlor to addltlon of heat sensltlve lngredlents, llke enzymes nt perfume.
To the above detergent matrlx, borax may be added ln lleu of metaborate. The necessary amount of sodium hydroxide ls added for thQ eonverslon of borax to metaborate. The metaborate ls then convorted to perborate through addltion of hydrogen paroxide.
After coollng to about 25 deg. C the heat sensltlve components of the co~po~itlon are added.

Claims (13)

1. A process for making an aqueous liquid detergent composition having a pH of at least 8, comprising an organic, non-soap anionic surfactant, a builder, and a solid perborate bleach, characterized in that perborate particles having a weight average particle diameter of from 0.5 to 20 micrometers are formed by in situ crystallization of the perborate.

2. A process according to claim 1 wherein sodium perborate tetrahydrate or monohydrate is added to an aqueous liquid comprising the anionic surfactant and the builder, and wherein the resulting slurry is stirred.

3. A process according to claim 2 wherein the perborate is sodium perborate monohydrate.

4. A process according to claim 1 wherein sodium metaborate is added to an aqueous liquid comprising the anionic surfactant and the builder, and wherein a stoichiometric amount of a peroxide is added, while stirring until completion of the reaction.

5. A process according to claim 4 wherein the peroxide is hydrogen peroxide or sodium peroxide.

6. A process according to claim 4 wherein borax is first converted to metaborate by addition of sodium hydroxide.

7. A process according to claim 1, wherein boric acid is added to an aqueous liquid comprising the anionic surfactant and the builder, and wherein a stoichiometric amount of hydrogen or sodium peroxide is added, while stirring until completion of the reaction.

8. A process according to claim 1 wherein said aqueous liquid contains in addition a water miscible organic solvent.

9. A process according to claim 8 wherein said water miscible organic solvent is ethanol.

10. A process according to claim 1 wherein the builder is selected from dodecenyl succinic acid, tetradecenyl succinic acid; dodecyl succinic acid; an 80:20 mixture of tartrate monosuccinate and tartrate disuccinate;
citric acid; and mixtures thereof.

11. A process according to claim 1 wherein less than 10% by weight of the resulting perborate particles have a diameter of more than 20 micrometers.

12. A process according to claim 11 wherein less than 10%
by weight of the resulting perborate particles have a diameter of more than 10 micrometers.

13. An aqueous liquid detergent composition having a pH at least 8, comprising:
a. at least 5X of an organic, non-soap anionic surfactant;
b. at least 5% of a builder;
c. from 1%-40% of a perborate bleach in the form of particles having a weight average particle diameter of from 0.5 micrometer to 20 micrometers, said particles formed by in situ crystallization; and d. from 5%-70% of a water-miscible organic solvent.