CA1135906A - Process for the production of washing powders of stabilised or enhanced appearance which contain fluorescent whitening agents - Google Patents

Abstract

Case 1-12163/1+2/=

Process for the production of washing powders of stabilised or enhanced appearance which contain fluorescent whitening agents Abstract of the Disclosure The invention relates to the production of washing powders of stabilised or enhanced appearance which contain a fluorescent whitening agent of the formula or of the formula

Description

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Case 1-12163/1+2/=

Proces~ for the productio~ of wa~3hing powder~ o ~tabili~ed or enhanced appearance which contain ~luorescen~

The prese~t invention relates to a process for the production o~ washing powders o stabili~ed and/or enhanced appearance which con~ain one or more fluoresce~ whitening agents o~ the bis-triazolylstilbene or naphthotriazolyl-stilbene type.

It has long been known to add fluorescen~ whi~ener to deterge~ts. Reference i~ made in this connection e.g. to ~nvironmental Quality and Saety, Suppl~ment Volume 4, Fluorescent Whitening Agent~, pages 59-62, ed. by C~ulston + Korte, G. Thieme Verlag, Stuttgart 1975; German patent specification 731 558.; and numerous other pa~ent specifica~ions relating ~o fluoresce~t-whitening agent~. ;
It is al30 known to add ~peci~ic fluorescent w~itening agents to detergents in powder form in ordex to enhance the appearance of the deterge~ts (see e.g~ J. of Color Appearance 1 (1972), 5, page 46).

Like other fluorescent whitening agents of the st~lbene-sulfonic aeid type, the compsunds of the formula (1~ herein (known fi~m U~S.patent specifica~ns 2 784 183 and 3 485 831) are most suitable or whitening and brightening textile~ in a wash ba h. 1~, however, they are incorporated in solid washing powders in the customary manner, they have an exceedingly undesirable drawback: not only do they barely enhance the appearance of the wsshing powder, but frequently even cause a deterioration in it~ appearance. Unattractive j, . . .

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greenish~yellow washing powder~ o r~duced commercial value are obtained in this manner.

The production of w shing powders usually comprise~
preparing a slurry from the individual componen~s (surfacP-active substa~ce, salts, builder, water etc.), and then drying this slurry, preferably by spray drying at elevated temperature. If desired, various further ingredients which are resistant to drying at elevated temperature (e.g. in the range from 200 to 300C) are ~ubsequently added to the dry wa~hing powder. Thu8 ~on-ionic surfac~an~s can be sprayed onto the washlng powder and/or cer~in addi~ives~
e.g. perborate, per ume3 9 enzymes, dye~ and other thermo-labile substance~, ble~ded with the otherwi e finished washing powder. Fluorescent whitening agents are usually added to the slurry before it is spray dried. The unattractive greenish-yel}ow w~shing powder~ reerred to above ~re usually ob~ained by means of thiY procedure.
Even the la~er addi~ion o~ fluorescent whitening agents is not able to effect any tabili~in~ ar ~nhancement of the appearance. This problem arise~ when i~corporating fluorescent whiteni~g gents of ~he bis-triazinylamino-stilbene-di ulonic acid typ~. Mean~ of improvements have already been proposed, e.g. the preparation of special crystal modifications o the fluorescent whitening agent or the additicn of substances having a large surace area.
Reference is made in this connection to e.g. German Auslegeschrift 2 747 088, German Offenlegungsschrit 2 659 675.
With respect to the problem of detergent yellowing arising with fluorescent whitening agents of the bis-triaæinyl-aminostilbene-2,2'-disulfonic acid type proposals have been published ~or enhancing the appearance of the wa~hing powders, e.g. by the addition of various substances such as alcohols, sugars, certain surfactants etc.

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Attention is drawn in this regard to Japanese patent publications Sho 51-5308, 51-6687, 46-35273 and 49-967. However, all these means are not suficient to solve the problem on which this invention is based, and they effect no adequate stabilising or enhancement of the appearance of the washing powder.

The present invention is based on the surprising observation that it is possible to obtain an excellent white appearance by a5pe~ffl~ process ox produ~ng wash ~ p~ers which contain fluorëscent whitening agent~, and that particularly good white effects can be obtained on the textiles washed with these washing powders~

The proces~ of the pre~ent invention for the production of washing powders of stabili~ed or enhanced appearance which contain one or more fluorescent whitening agen~s of the ~ormula ~ CH=C3~ N

or of the forrnula ~~
~0 ~ -C~oC~ N ~

wherein Rl is hydrogen or chlorine, and M is hydrogen, an alkali metal, ammonium or amine salt ion, con~ists in ' ' , ' ~ ~ '`

.. ~ ,. .

first dissolving or dispersing the fluore~cent whi~ening agent or agents in a mix~ure o water and a polyvinyl alcohol or polyvinyl pyrrolidone which is soluble or swellable in water, and adding the solution or dispersion so ob~ained, which may additionally contain a polya~hylene glycol, a surfactant containing ethyleneoxy and/or propyleneoxy groups, or a cellulose ether, to the washing powder slurry and subsequently drying thi.s slurry, or, optionally after the addition o further washing powder component3, spraying said solution or dispersion onto a dried unfinished washing powder, or drying the solution or dispersion to a powder, suspending said powder in water7 adding the resultant suspension to the washing powder slurry, and subsequently drying this slurry.

Preferred alkali metal ions M in formula (1) are sodium and potassium ionsO Sui~able amine salt ion~ M are principally those of the ormu~a - ~ 1R2, wh~rein Rl is hydrog~n or unsubs~ituted or substi~uted alkyl, and ~ is unsubstitu~ed or subs~i~uted alkyl. Pr~erred substituted alkyl radicals, which preferably co~tain 1 to 4 carbon atoms, are hy roxyalk~l, cyanoalkyl~ haloalkyl and benzyl.
M is preerably hydrogen, sodium, potassium, or ammonium.

It is an e~ser~tial feature of the proces~ of the invention that the fluorescent whit~ning agent is dissolved or ~~
dispersed in ~he mix~ure of water arld a polymer (polyvinyl alcohol or polyvinyl pyrrolîdone, or mix~ures o~ these polymers~, as otherwise the desired effect is not achieved.
Particùlarly advantageous results are obtained with poIy-vinyl alcohol.

It is preferreia to employ polyvinyl alcohols having a degree o~ hydrolysis of 80 to 100 mol.% and a viscosity between 3 ~:,' , :

~ 5 --and 66 cP, especially those having a degree o hydroly~is of 9o to 100 mol.% and a viscosity of 3 to 10 cP. In this specifica~ion, all viscosity values indicated for pol~vinyl aleohol are measured in a 4% aqueous solutlon at 20C~ . -.
Polyvinyl pyrrolidone~ ~uitable for the process o~ the present invention preferably have a molecular weight of 10~000 to 360~000, especially ~ro~ 15,0~0 to 50,000. It will be appreciated that the term "polyvinyl pyrrolidone"
encompasses not only the polymeri~ation products o~ unsub-stituted vinyl pyrrolidone, but also those o~ substitut~d, e.g. alkylsubstitutedg vinyl pyrrolidones.

The specified polymers form solutions with water i~ ~hey do not have a high molecular weight. However, it sufices al~o if the polymers ~well or are dispersed in water.

The aqueou~ m~xture~ in which the fluorescent whitening agent is ~ ~olved or ~sp~sed prefe ~ ly contain at least 0.01% by weight, ~08~ preferably at leas~ 0.05~--by weight, of the respective polymer. The m~x~mum eontent of poly~er is determi~ed by the flowability of the mlxture ob~ai~d and depe~ds on the mol@cular w~gh~ of Ehe respecti~e polymer.
~here a flowable mlx~ure i~ ob~ained, high concentration~
of polymer do not impair the operability of the proces~.
In practice, sultable concentration~ of polym~r in the ~~~
mixture are preferably between 0.01 and 20% by wei~ht, especially b~ cn O.Q5 and 10% by weight.

To enhance ~he appearance of the f~nished washing powder further, it is possible to add ~o ~he mi~tur~ of wa~r and polyvin~l alcohol or polyvinyl pyrrolidorle in whlch the ~luore~ce~t whi~enlng ager~'c i5 dissolved or dispersed, a polyethylene glycol, a surface-actlve ~ubstance .

containing ethyleneoa;y and/or propyleneoxy group3, or a cellulo~e ether. An enharlced efect is obtained iTI particular with the ollowing substance~
a) polyethylene glyc:ols, prefer~ly those having a molecular weight o 100 'co 10 ,000;
b) cellulose ether~, e.g. hydroxypropyl ~ellulo~e, methyl cellulose, carboxymethyl cellulose, methylhydroxypropyl cellulo~e;
c) copolymer o~ polyethylene oxide and pol~rpropylene oxide oi~ ~che formula ~olc2~l4v)X (C3~6)y (C2~ ) Z
wherein the content of @thylene oxide (~ + z) is lO to 85% by weight, and that o propylene oxide (y) i~ 15 to 90% by weigh~. The molecular weigh~ of such polymers is between 2000 and 20 ,000;
d) ethoxylated alipha~ic alcohol~ of the formllla E~ ~C2E140) a ~

wherein a i9 an integer between 10 and 200, e~pecially betwee~ 30 a~d 200, and R is alkyl of L2 to 20 carb~r~ a~om~, alkenyl of 12 to 18 carbo~ atom~, or phenylalk~l e) ethoxylated alkylpheraols o the formula -C1 ( C~2C~20 ) b Z
~=,~

wherein R' is alkyl of 6 I:o 18 carbon ato~, Z is hydrogen, -S03~' or P03~f', in which Ms is hydrogen, an alkali metal or ammonium ion, and b is an integer between 6 a~d 30.

Preferably, ~he amou~ in which the abo~e rnentioned optional compone~ts are added a~e 1 to 50 timeg, especially 1 ~o 20 timeq, e.g. 1 to lO time~, the amoun~ of polyvinyl ,. , : , . ;" ~ . ,.:

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alcohol or polyvi~yl pyrrolidone. or mixture~ thereo~, present in the aqueou mixtu~e.

The 1uorescent whitening agent can be dissolved or - :
dispersed e.g. at room temperature i~ the medium consis~ing of water and ~he polymer specified above. Frequen~ly, h~wPver, it i~ advantageou to h~at the mixture, e.g. to a temperature in the range ~rom 30 to 100C, preferably from 40 to 80C, e~pecially from 60 to 80C, whereby a more rapid or a better solu~ion or dispersion o~ the 1u-orescent whi~ener in the mix~ur~ i~ of~en achieved, If a di~persion i9 ob~ained wh~n mixing the ~luorescen~
whitening agent with the polymer solution or disper~ion ~ . .
and this is usually so - then it can be advantageou~ to subj~
this dispersion to a wet grinding before the additio~ to the detergent in order to effect a bet~er disper~ion o the ~luorescen~ whi~ening agent by reducing ~he par~icle ~ize.
The wet grinding can be carried out e.g. by adding glas~
bead~ to ~he dispersion and grinding. it in a ball mill.
The temperature during the grindi~g procedure can be m ~he ran~e between room tempera~ure and the boiling poin~ of the dispersio~, e.g. be~ween 20 ~nd 80C. Dependisg on the de~ired finene~ o ~he di per8ion, the grinding can ~ake up to ~everal hour~, e.g. ~r~m 1 to 10 hours.

The amou~t of fluores~e~t whi~ening agent to be dissolved or dispersed d~pends on the desixed ~mount i~ the inished washing p~wder. It can be e.g. from 0.001 to 10% by weigh~.
preferably fro~ 0~01 to 5% by welgh~, e~p~cially from 0.05 to 2% bylweigh~. Very good resul~s are ob~ined wi~h amou~ts from 0.1 to 0.5% by weigh~.

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The ratio between the fluorescent whitening agent and the polymer or polymer mixture in the aqueous solution or dispersion, or in the dried 1uorescent whitener preparation obtained therefrom, can vaxy wit:hin wide limlts and depends on the fluorescent whitening a~en t employed and the nature o~ the polymer or polym~rs. For e~ample, ~he ra~io of fluorescent whitening agent to polymer can be about 9:1 to 1:10. When using polyvinyl alcohol, it is pre~erably in the region of 80:20 to 40:50, most preferably of 70:30. When using polyvinyl pyrrolidone, the ratio of fluorescent whitening a~ent to polymer is e.g. between 1:1 and 1:10, preferably about 1:9.

Within the scope o the proce~ of this invention, praferred fluorescent whitening agents are those of the ~ormulae CH=CH~ N ~ I I (3) and So3~ . --I$ ~ c~=c~ .-N
SO3M' S~3M' wherein M' is hydrogen, sodium or potassium.

The fluore~cen~ whitening age~t is preferably incorporated in the de~ergent by adding the solution or dispersion (o~tained as d~escribed above) to the washing powder slurry (mixture of thle customary components) and the~ drying the . : . ....................... : :; . ~ .

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slurry containing the fluore~cent whitening agent in ~he conventional manner. If the slurry contains substances which are unstable at ele~a~ed t:empera~ure (e.g. car~ain surfactants, such as those which contain ethyleneoxy groups), then it is dried at l~i temperature9 e.g. bel~w . -50C. Normally, however, ~he sll~ry is dried a~ ~levated temperature, e.g. up to 300C. i.or example by conventlonal spray drying or 1uidised bed drying.

The solutlon or dispers~on can, however, also be sprayed onto the dried washin~ powder (e.g. by spray drying in a pray tower) in the co~en~ional man~er employed ~or obtalning washing powd~ containi~g ~hermolabile ~ub~ta~c~, e.g. certai~ su~fac~ants con~ai~l~g e~hyleneoxy groups. This con~titu~e3 a very lmpor~an~
method ln practic~ i3, however, also po~ble to m~x the solution or dLspersion with suitable detergent componen~s which are r~ally added to the o~herwis~
~ini~hed wa~hing p~wder a~ the co~lusion of ~he production process (a.g. with sodium perborate, bleachi~g agents such as chlorin~ donor~, e~z~mes, parfum~ etc,)~ and then to apply thi~ mlx~ure ~o ~he already ex~ing re~idual p~wde~.

It is decisive for the success of the proces~ o the invention th~t the 1uorescent whitening agent should be dissolved or .inely dispersed in the above described mixture. The best results are obtainet when the fluoresc~nt whitening agent is dissolved or very inely dispersed (e.g. by an additional grinding~ in the corresponding medium.

A second variant of incorporating the fluoreseent whitening agent or agents in the washing powder by the process of the invention consis~s in drying the aqueous ., ,-, ,- : . , ,: :

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solution or dispersion o fluore cent whitener and polymer to a ine powder, suspending this powder in water, and mixing this suspension with the washing powder slurry and drying ~his latter in conventional manner, e~g. tha~ :
described above.

This second vaxiant i~ e~pecial:Ly advantageou~ i~ it i~
not possible to dissolve the flllorescent whitening agent in the aqueous polymer solution or disper~ion, and only a dispersion is obtained. In this case, a further enhan-cement o the appearance o ~he washing powder can be achieved by irst drying the dispersion. As already described, it is often advantageous ~o subject the di persion of the fluorescent whitening agent and polymer or polymers to a wet grinding procedure before drying this disper~ion.

The solution, i~ partlcular di~persio~7 can be dried by conventional methods. The disper~ion can simply be dried in a drying cab~net~ e.g,, in the temperature range ~rom 40 to 100C, pre:erably from 50 ~o 80C, and the dry substance obtained i~ ground to a fine powd~rO However, it is advantageous to dry the dispersion with hot air in a spray tower to produca a fine powder. The powder containing the ~luorescent whitening agent and polymer or pslymers is incorporated in the wa~hi~g powder by suspending it in -~-w~ter a~d adding this suspension to the washing powder slurry, which is then dried in conventional manner, e.g.
al~o by spray drying.

A further advcmtage af ~he above described second variant o the process o the invention is that the powder obtained by drying the dispersion (fluorescent whitener preparation in powder fo~l) can be easily stored over a prolonged period .. . . . ~ . .. . . ..
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of time without dis~olouration ~r other diminution of the quality o the fluorescent whitener. This preparation can therefore also be used as a commercial formNlation of the respective fluorescent whitening agent. Regardless of where the preparation is produced, the! incorporation in a wa~hing powder can ba e~ected anywhere.

In contradistinction to the variant~ of the proce~9 o the lnvention, the addition o~ the respective polymQrs and fluorescent whi~ening agents, without disqolving or dispersing them in the queou~ polymer solution or dlspersion, to the washing powder ~eparately, doe~ not efect the desired ~nhancement of ~he appear~nce of ~he washing powder (attention is also drawn in this connection --to the Examples). However, if the washing powder is produced in the manner according to the invention~ the~, surprisingly, ~here no longer occurs any deter~oration in ~he appearance of the washing powder during storage, although this would be expected because of ~he presence o large amounts of elee~roly~e~ and ~he attendant "~al~ing ou~" action on the fluorescen~ whi~ening agent.

The proceYs of th~ i~venti~n can b2 used for incorpora~ing the fluore~c~nt whi~rli~ agen~ in any de~ergenP co~pc)~ltion in powder for~. Such composition~ preferably contain the kn~wn mixtures of acti~e detergen~s, for example ~oap in ~~~
the for~ of chips and po~ders, sy~thetics. soluble salts o~
sulfonic acid hemies~er~ o higher ~at~y alcohols, xyl-~ulonic acids with higher and/or mul~iple alkyl ~ubs~ituent~, sulfocarbo~li.c acid esters of mediwm to higher alcohols.
fa~ty acid ac~laminoalkyl- or acylami~oaryl-glycerol sulfona~e~ and pho~phoric acid esters o~ fat y alcohol~.
Suitable builders which oan be us~d axe, for exa~ple, alkali metal polypho~phates a~d polymetaphosphates, alkali metal :,' .
~ . . .
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pyrophospha~Q~ or alumino3ilicat~, alkali metal salt~ o~
carboxgmeth~lcellulose and other soil redeposicion inhibitors, and also alkali metal. ~ilicates, al~li metal carbonate , alkali metal sul:eates, alkali metal perborates, nitrilotriacetic acid, ethylenedi.aminetetraacetic acid, and foam s~ibilisers, such as alkanolamide of higher atty acid3. The deter~ent~ can further contain for example:
a~tis~a~c agents, fat res~orati~e skln pro~eetives uch a~
la~olin, en2ym~s, antimicrobial agents, perfum@~, coloura~t~, and bleaching activator~ ~uch as tetraacetylethylenediamine or tetraaec~ylglycoloril. Examples o~ sui~able de~ergen~s will be fou~d in the illu~tra~ive Examples whieh follow.

Incorporation o~ the 1uore~cent whltening a8en~ o the formulae (1) or (2) in a washing powder by the process of this inNention r~ults a~ lea~ i~ a stabilising of ~he appearance of the w~shing p~wd~r, i.e. the washlng powd~r trcated wi~h fluoresc~nt whitening agan~ is at lea~t as white in appearance as the washing powder wi~hout fluorescent whi~ening ageTI~. The of~en.obse~ved greenish or yellowish diss::olouration of the de~ergent caused by the addition of fluor~scent w~iteuer can thu3 be a~ro~ded.
Usually, however, the proces~ of ~he invention ef~ec~s a~
enhancemen~ of the appearallcP of the ~ashi~g powder, i~e.
the powder treated wL~h fluoreYcen~ whi~ener has a whlter appearance han one whi~h does not contain white~ing agent.

The washiry3 powderx ob~c~ined by the process of the iTrven~ion are most suitabl0 for washing textlles to produce a good white effec~ orl ~che washed sub~1:rat~.

It is a further obj ect of this inventio~ to provide the aqueous solutions or dispersions which contain osle or more fluorescent whitening agents of th~ :Eormulae (1) or (2)~ a polyvinyl .
~..

alcohol or po~vin~Jl ~ one which ~ ~r-so~bleor sw~ ~ ~ ~r, and op~on~ly apolyethylene glycolg a surfactant containing ethyleneoxy and/or propyleneoxy groups, and/or a cellulose ether9 and which can be incorporated in washing powders -by the process of the invention. The composition and preparation o~ these ~olutions or dispersions, as well as the preerred embodiments o~ these ssLutions or dispersions, are described above.

It is yet a further ob; ect of the invention to provide the preparations obtained from the solutions or disp~rsions desc~ibed above l:~y drying and ~ comprise one or ~re ~orescen'c whitQning agentæ of the ~ormulae (1~ or (2), a polyvinyl al~ohol or polyvinyl pyrrolidone, and optionally a polye~hylene ~
glycol, a surfactan~ containing ethyleneo~y and/or propyleneox~ group~, and/or a cellulose ~ther.

These dry preparations ~erab~ compr~e one or more fluorescent whitening agen~s of the formulae (1~ or ~2)and a poly~nylak~hol having a degrae of hydroly~is cf 80 to 100% and a viscosi~y of 3 to 66 cP, or a polyvinyl pyrrolidone with a molecular weight of lO~000 to 360,000, the ratio of fluoresee~t whitening agent to polymer being preferably 9:1 to 1:10, when using poly~inyl alcohol especially ~rom 80:20 ~o 40:50, preferably 70:30, and when using polyvinyl pyrrolidone7 especially 1:1 to 1:10.

Most preferably~ in addition to containin~ the fluore~cent whitening agerlt, such a preparation contains a polyvinyl alcohol having a degree of hydrolysis of 90 to 100% and a viscosity of 3 to lOcP.

Preferred fluorescent whitening agents in the above preparations are those o the formula (4), especially those of the formula (3), and mixtures thereof.

: . . , ~, : .

.

The following Examples illu~trate the proce~s of the invention in more detail, without implying any resl:riction to what is d~scribed therein, as well a~ the solutions or dispersions employed in this process and the dry preparations .
obtained therefrom.

... . . . . . . . . . ..

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~ ~ 3 ç~ 40 mg of the fluorescent whitening agent of the formula (3), wherein M' is sodium, are dispersed at 60C in a mixture of 0.2 g of polyvinyl alcohol (viscosity 4 cP, degree of hydrolysis 98%) and 20 ml of water. A
homogeneous paste is obtained by stirring this suspension at room temperature with 20 g of a detergent of the following composition in 20 ml of deionised water:
alkylarylsulfonate 17 9 5%
fatty alcohol 3ulfa~e 3.7 coconut ~at~y acid mono-etha~olamide 2.7%
sodium tripolyphoYphate39.0%
sodium 5ilicate 4.0%
magne9i~m ~ilicate 2.0%
carboxymethyl cellulosel~OV/o sodium ethylenediami~e~etra-acetate 0.5%
water 6.7 sodium sulfate to make up 100.0%

This paste (slurry) is spread on a porcelain dish, dried for 12 hours a~ 30C under 500 torr in a vacuum drying cabinet, then loosened with a spatula, and subsequently dried for a further 8 hours at 30C/200 torr. The detergent is then pressed through a sieve with a 0.8 mm mesh, beneath _ which there is a second sieve with a 0.315 mm mesh.

On this sieve there remains a powder of uniform particle size which is used for determing the appearance~ The washing powder so obtained has an attractive white appearance.

Example 2: 30 mg of the fluorescent whitening agent of the formula (4),wherein M' is potassium, are dissolved ~3~

in a mi~ture of 0.8 g of polyvinyl alcohol (viscosity 4 cP, degree of hydrolysis 98%) and 20 ml of deionised water. This solution is processed to a paste with a de~en~
of the composition described in Example 1, afording a washing powder with an attractive white appearance.

Example 3- 30 mg of the fluorescent whitening~agent of the formula (4), wherein M' is potassium, are dissolved in a mixture of 20 mg of polyvinyl alcohol (degree of hydrolysis 97-99%; viscosity 5 cP), 100 mg of polyethylene glycol 4000 (mol. wt. about 4000) and 20 ml of water.
This solution is processed to a paste with a detergent of the composition des~bed in Eæampleland the paste is then dried, a~fording a washing powder with an attractive white appearance.
The paste (~lurry) can also be dried by spray drying.

Example 4: 30 mg of the fluorescent whitening agent of the formula (4)7 wherein M' is potassi~m,are dissolved in a mixture o~ 1 g of polyvinyl p~rrolidone K25 (mol. wt.
about 24,000) and 20 ml of water. This solu~ion is processed to a paste with 20 g of a detergentofthe composition described in Example 1 and the paste is dried in the usual manner and pulverised, affording a washing powder with a pure white appearance.

Example 5: 30 mg of the fluorescent whitening agent of the formula (3), wherein M' is potassium, are dissolved at 80C in a mixture o 200 mg of polyvinyl pyrrolidone K25 (mol. wt. about 24,000) and 20 ml of water. This so~tion is stirred to a paste with 20 g of a detergent of the compo-sition described in Example 1 and the paste is dried in the -.. : '. .' ' . ' : ' . ; ' ' :

3L~ 3~r~

usual manner and pulverised, afording a washing powder with a pure white appearance.

A similar result is obtained using 1000 mg of polyvinyl pyrrolidone K25.

Example 6: Example 5 is repeated using 1000 mg of poly-e~hylene glycol 400 (mol. wt. about 400) instead o~ 200 mg of polyvinyl pyrrolidone K25. A washing powder with an attractive white appearance is likewise obtained.

Comparl n Example A: 30 mg of the 1uorescent whitening agentof the formula (3)wh~ein ~ is sodium are stir ~ at20C m 20ml ~ d~sed water which contains about 1 g of a detergent of the composition indicated in Example 1. Then a further 19 g of the detergent are added and mixed until a homo-geneous paste is obtained. This paste is spread on a porcelain dish and dried for 4 hours a~ ~0C/400 torr in a vacuum drying cabinet, then loosened with a spatula, and subsequently dried for 3 hours at about 80C under 250 torr~

The washing powder is reduced to small particles and its appearance determined as described in Example 1. The washing powder so obtained has an unattractive greenish appearance which is poorer than that of the washing powder which does not contain fluorescent whitener.

A washing powder of a greenish hue is likewise o~tained by substituting the fluorescent whitening agent of the formula (4), wherein M' is potassium, for that o~ the formula (3)wherein M' is sodium, and repeating the above procedure.

: - . .; , .

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Comparison Exam~le B- To the detergent slurry o Comparison Example A which contains the 1uorescent whitening agent of the formula (3), wherein M' is sodium, or (4), wherein M' is po~assium,is additionally mixed, before drying, 0,2 g of polyvinyl alcohol (viscosity 4 cP, degree of hydrolysis 98%). The slurry is then dried and pulverised as described in Comparison Example A. The washing powder so obtained has about as unattractive an appearance as ~hat~of Comparison Eæample A

This Example shows that it is not suficient to add the polymers to be employed in the process of the invention to the detergent, but that the fluorescent whitening agent must be dissolved or dispersed beforehand in th~
appropriate medium. A subsequent solution or dispersion in the detergent itself is obviously not possible.

Example 7: A suspension o 50 g of the fluorescent whitening agent-of the formula (4),~herei~ k~ is ~dium,in 75mlofwater is dispersed in a solution of 21 g of polyvinyl alcohol (degreee of hydrolysis 98%j viscosity 4 cP) in 100 ml of water. The dispersion is ground in a ball mill for 5 hours at 50C with 250 g of g~ss beads (diame~er lmm). The g~s beads are then removed and the dispersion is dried by spray drying with hot air. A white powder is obtained. The dispersion can also be dried at 50C in a drying cabinet with subsequent pulverisation of the dry preparation.

The above powder is incorporated in a washing powder by the following procedure: 70 mg of the dry powder obtained in this ~xample are suspended in water and this suspension is added to 25 g of a detergent of the composition as indicated in Example 1 in 25 ml of water. The resultant .. . . . .

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paste (slurry) is dried either by the method of Example 1 or in a spray tower with hot air. In both cases the resultant washing powder has a pure white appearance which it also retains ater storage in moist air.

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Claims (35)

What is claimed is

1. A process for the production of a washing powder of stabilised or enhanced appearance which contains one or more fluorescent whitening agents of the formula or of the formula , wherein R1 is hydrogen or chlorine, and M is hydrogen, an alkali metal, ammonium or amine salt ion, which process com-prises first dissolving or dispersing the fluorescent whitening agent or agents in a mixture of water and a polyvinyl alcohol or polyvinyl pyrrolidone which is soluble or swellable in water, and adding the solution or dispersion so obtained, which may additionally contain a polyethylene glycol, a surfactant containing ethyleneoxy and/or propyleneoxy groups, or a cellulose ether, to the washing powder slurry and subsequently drying this slurry or, optionally after the addition of further washing powder components, spraying said solution or dispersion onto a dried unfinished washing powder, or drying the solution or dispersion containing the fluorescent whitening agent or agents to a powder, suspending said powder in water, adding the resultant suspension to the washing powder slurry, and subsequently drying this slurry.

2. A process according to claim 1, which comprises adding the solution or dispersion containing the fluorescent whitening agent direct to the washing powder slurry and subsequently drying said slurry, or, optionally after addi-tion of further washing powder components, spraying said solution or dispersion onto a dried unfinished washing powder.

3. A process according to claim 1, which comprises drying the solution or dispersion containing the fluorescent whitening agent and suspending the fine powder so obtained in water, adding this suspension to the washing powder slurry, and subsequently drying said slurry.

4. A process according to claim 3, which comprises drying the solution or dispersion by spray drying with hot air.

5. A process according to claim 1, which comprises wet grinding the dispersion before it is incorporated in the washing powder slurry or before it is dried.

6. A process according to claim 5, wherein the wet grinding procedure is carried out in a ball mill in the temperature range between room temperature and the boiling point of the dispersion.

7. A process according to claim 1, which comprises dissolving or dispersing the fluorescent whitening agent in a mixture of water and a polyvinyl alcohol having a degree of hydrolysis of 80 to 100% and a viscosity between 3 and 66 cP, or a polyvinyl pyrrolidone having a molecular weight of 10,000 to 360,000.

8. A process according to claim 1, wherein the mixture of water and the polymer contains at least 0.01% by weight of polymer.

9. A process according to claim 1, wherein the ratio of fluorescent whitening agent to polymer in the aqueous solution or dispersion, or in the dried powder obtained therefrom, is 9:1 to 1:10.

10. A process according to claim 9, wherein the ratio of fluorescent whitening agent to polyvinyl alcohol is 80:20 to 40:50.

11. A process according to claim 9, wherein the ratio of fluorescent whitening agent to polyvinyl pyrrolidone is 1:1 to 1:10.

12. A process according to claim 1, wherein the mixture of water and polyvinyl alcohol or polyvinyl pyrrolidone, in which the fluorescent whitening agent is dissolved or dis-persed, additionally contains a polyethylene glycol, a sur-factant containing ethyleneoxy and/or propyleneoxy groups, or a cellulose ether.

13. A process according to claim 12, wherein the mixture additionally contains a polyethylene glycol having a mole-cular weight between 100 and 10,000, a cellulose ether, a copolymer of polyethylene oxide and polypropylene oxide having a molecular weight of 2000 to 20,000 of the formula H0(C2H40)x-(C3H60)y-(C2H40)zH , wherein the content of ethylene oxide (x + z) is 10 to 85% by weight and the content of propylene oxide (y) is 15 to 90% by weight, an ethoxylated alcohol of the formula H(C2H4O)a-OR , wherein a is an integer between 10 and 200, and R is alkyl of 12 to 20 carbon atoms, alkenyl of 12 to 18 carbon atoms, or phenylalkyl, or an ethoxylated alkylphenol of the formula , wherein R' is alkyl of 6 to 18 carbon atoms, Z is hydrogen, -SO3M' or -PO3M', in which M' is hydrogen, an alkali metal or ammonium ion, and b is an integer between 6 and 30.

14. A process according to claim 2, wherein the solution or dispersion is added to the washing powder slurry and the slurry is then dried.

15. A process according to any one of claims 1 to 3, wherein the dissolving or dispersing of the fluorescent whitening agent in the aqueous polymer mixture is acceler-ated by heating in the temperature range from 40° to 80°C.

16. A process according to claim 1, wherein the polymer is a polyvinyl alcohol having a degree of hydrolysis of 90 to 100% and a viscosity of 3 to 10 cP.

17. A process according to claim 1, which comprises the use of a fluorescent whitening agent of the formula wherein M' is hydrogen, sodium, potassium or ammonium.

18. A process according to claim 1, which comprises the use of a fluorescent whitening agent of the formula wherein M' is hydrogen, sodium or potassium.

19. An aqueous solution or dispersion containing a fluorescent whitening agent of the formula (1) or of the formula (2), wherein R1 is hydrogen or chlorine, and M is hydrogen, an alkali metal, ammonium or amine salt ion, a polyvinyl alcohol or polyvinyl pyrrolidone which is soluble or swellable in water, and optionally a polyethylene glycol, a surfactant containing ethyleneoxy and/or propyleneoxy groups, and/or a cellulose ether,

20. A solution or dispersion according to claim 19, which contains a fluorescent whitening agent of the formula (1) or (2), a polyvinyl alcohol having a degree of hydro-lysis of 80 to 100% and a viscosity of 3 to 66 cP, or a polyvinyl pyrrolidone having a molecular weight of 10,000 to 360,000, the ratio of fluorescent whitening agent to polymer being 9:1 to 1:10.

21. A solution or dispersion according to claim 20, which contains a fluorescent whitening agent of the formula (1) or (2) and a polyvinyl alcohol, the ratio of fluores-cent whitening agent to polyvinyl alcohol being 80:20 to 40:50.

22. A solution or dispersion according to claim 20, which contains a fluorescent whitening agent of the formula (1) or (2) and a polyvinyl pyrrolidone, the ratio of fluorescent whitening agent to polyvinyl pyrrolidone being 1:1 to 1:10.

23. A solution or dispersion according to claim 19, which contains at least 0.01% by weight of the respective polymer.

24. A solution or dispersion according to claim 20, which contains a polyvinyl alcohol having a degree of hydrolysis of 90 to 100% and a viscosity of 3 to 10 cP.

25. A solution or dispersion according to claim 19, which, in addition to containing the fluorescent whitening agent and polyvinyl alcohol or polyvinyl pyrrolidone, contains a polyethylene glycol, a surfactant containing ethyleneoxy and/or propyleneoxy groups, or a cellulose ether.

26. A solution or dispersion according to claim 19, which contains a fluorescent whitening agent of the formula wherein M' is hydrogen, sodium or potassium.

27. A solution or dispersion according to claim 19, which contains a fluorescent whitening agent of the formula wherein M' is hydrogen, sodium or potassium.

28. A preparation consisting of a fluorescent whitening agent of the formula (1) or of the formula (2) , wherein R1 is hydrogen or chlorine, and M is hydrogen, an alkali metal, ammonium or amine salt ion, a polyvinyl alcohol or polyvinyl pyrrolidone, and optionally a poly-ethylene glycol, a surfactant containing ethyleneoxy and/or propyleneoxy groups, and/or a cellulose ether.

29. A preparation according to claim 28 consisting of a fluorescent whitening agent of the formula (1) or (2), a polyvinyl alcohol having a degree of hydrolysis of 80 to 100% and a viscosity of 3 to 66 cP, or a polyvinyl pyrrolidone having a molecular weight of 10,000 to 360,000, the ratio of fluorescent whitening agent to polymer being 9:1 to 1:10.

30. A preparation according to claim 29 consisting of a fluorescent whitening agent of the formula (1) or (2) and a polyvinyl alcohol, the ratio of fluorescent whitening agent to polyvinyl alcohol being 80:20 to 40:50.

31. A preparation according to claim 29 consisting of a fluorescent whitening agent of the formula (1) or (2) and a polyvinyl pyrrolidone, the ratio of fluorescent whitening agent to polyvinyl pyrrolidone being 1:1 to 1:10.

32. A preparation according to either of claims 29 or 30, which contains a polyvinyl alcohol having a degree of hydro-lysis of 90 to 100% and a viscosity of 3 to 10 cP.

33. A preparation according to claim 28 consisting of a fluorescent whitening agent of the formula (1) or (2), a polyvinyl alcohol or a polyvinyl pyrrolidone and a poly-ethylene glycol having a molecular weight between 100 and 10,000, a cellulose ether, a copolymer of polyethylene oxide and polypropylene oxide having a molecular weight of 2000 to 20,000 of the formula HO(C2H4O)x-(C3H6O)y-(C2H4O)zH , wherein the content of ethylene oxide (x + z) is 10 to 85% by weight and the content of propylene oxide (y) is 15 to 90% by weight, an ethoxylated alcohol of the formula H(C2H4O)a-OR , wherein a is an integer between 10 and 200, especially between 30 and 100, and R is alkyl of 12 to 20 carbon atoms, alkenyl of 12 to 18 carbon atoms, or phenylalkyl, or an ethoxylated alkylphenol of the formula , wherein R' is alkyl of 6 to 18 carbon atoms, Z is hydrogen, -SO3m' or -PO3M', in which M' is hydrogen, an alkali metal or ammonium ion, and b is an integer between 6 and 30.

34. A preparation according to claim 28, which contains a fluorescent whitening agent of the formula wherein M' is hydrogen, sodium or potassium.

35. A preparation according to claim 28, which contains a fluorescent whitening agent of the formula wherein M' is hydrogen, sodium or potassium.