CA1054311A - Encapsulation process - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Particles of an organic chlorine bleaching agent are coated with a complete and continuous coating by spraying. The coating is a fatty acid, preferably having 12-20 carbon atoms, and when a second coating is applied by treatment with a solution of an alkali hydroxide, e.g.
sodium, potassium, or calcium hydroxide, effective, completely coated, non-pinholing bleach particles are obtained.

Description

~ c ~.358 ~ 5~3~L~

This invention relates to a particulate organic chlorLne bleaching agent having a coating of a special type.

In the detergent bleach field particulate organic ch:Lorine ble~lching agen-ts, such as potassium dichloroiso-cyanurate, sodium dichloroisocyanurate, and the hydrates thereof are employed in home laundering operations as dry bleachproduGts to be added separately to a washing machine or for use in admixture with particles of a detergent composition to form a commercially acceptable detergent - dry bleach combination. Because of their highly reactive nature the particles must not only be thoroughly and imperviously coated to avoid contact of the bleach particles with the detergent particles, but the coated particles must not attack textile materials or the dyes thereon under washing conditions. Although prior-art processes may provide thorough and uniform coatings, the coated particles suffer the defect - that they can attack fabric causing 'pinholing'.
Pinholing is caused by solid particles of an organic `~
chlorine bleaching agent being able, through incomplete .
dissolution in the washing liquor, to come into physical contact with fabric.
- Thus the problem which~it is necessary to solve in order successfully to coat an organic chlorine bleaching agent is this: that the coatings which are most satisfactory from $he point of view of protecting $he bleaching agent from ;
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atmospheric attack are also the ones which result in reduced bleaching performance, either because they do not release the bleaching agent at all, or because they release it too slowly (which leads to low available chlorine in the washing liquor), or because they release it too quiGkly ~rodllcing pinholing.
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We have now discovered that the above problems can be miti~ated by the use o~ a clouble coating consisting o an inner fa-tty acid layer covered with a layer of a water soluble salt thereo~
~ccordingly, the present invention prov:Ldes particles of an organic chlorine bleaching agent having a double coating, an inner layer consisting predominantly of a fatty acid having a melting point above about 105F and an outer layer consisting predominantly of a water-soluble salt thereof The present invention is described here using potassium dichloroisocyanurate as an example.
Potassium dichloroisocyanurate, typical of the ~ ;~
cyanurates suitable as chlorine bleaching agents, is commercially available and may be obtained from the Monsanto Chemical Company. The chemical structure of this compound may be represented by the graphic formula~

/ N
`~ 20 ` = I I =
~ ~ Cl - N N - Cl ,'., `\C/ ; :, ;` :
Information regarding this and three related compounds may be found in Monsanto Technical Bulletin I-177. ~;
~owe~er any particulate organic chlorine bleachîng agent may be used, although mono-, di- or trichloroiso- ;
cyanurates are preferred.

Among the organic chlorine bleaching agents suitable for coating are potassium dichloroisocyanurate~ ~

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sodium dichloroisocyanurate, monochloramine, dichloramine~
nitrogen trichloride, ~(mono-trichloro)-tetra-(mono-potassium dichloro)~ penta-isocyanurate, l,3-dichloro-5,5-dimethyl hydantoin, paratoluene sulfondichloroamide, trichloromelamine, N-chloroammeline, N-chlorosuccinimide, N,N'-d:ichloroazodi~
carbonamide, N-chloro acetyl urea, N,N'-dichlorobiuret, chlorinated dicyandiamide, trichlorocyanuric acid, and dichloroglycoluril.
The present invention is applicable to particulate substances having a wide range of particle si~es, so long as the particles are-fluidizable. Preferably, pc~rticles having an average diameter of from 1.2 to 1.6mm are used.
The solvent for the coating substance will be selected with due regard for its volatility and inertness to~ard the core material. Preferably the boiling point of the solvent ~ill be about 90F to about 180F~ m e dissolving capacity of the solvcnt will be considered in determining whether a solvent havir,g a boiling point in the upper portion of the foregoing range cc~n be used. For example, if relatively little solvent is re~uired for the coating substance, the boiling point can be higher thc~n in inst~nces ~her0in a high proportion of sol~ent is needed.
In the double coating~in accordanee with the invention, it is essential that the first coating be a saturated fatty (alkanoic) acid which is solidifiable c~nd which remains solid at temperatures likely to be encountered during manufacture or storage, for example, a temperature of at least about 105F. Suitable fatty acids are the well- -kno~m n-alkanoic acids having from about 12 to about 20 carbon atoms. A particularly suitable fat-ty acid is Emersol 132 (trademark of Emery Industries, Inc.), ~hich is substantially . ' ~

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~:. ': ' , c B.358 ~0~ ~3 11 45% stearic acid and 55% palmitic acid and which melts at about 131-132F. The fatty acid is applied as a solution in a suitable solvent, methylene chloride bein~ preferred because of its compatibility, non-reactivity with ch~orine S bleachi~ agents, nonflammability, and low toxicity.
~loreover, the fatty acid will be selected with due regc~rd to its melting point in relation to the use to which the coated particles are to be put. For example, in the case o~ a double-coated product intended for use as a bleaching agent in a home laundering operation, the melting point of the fatty acid may be some~hat higher than the temperature of the wash solution, but not so high that it is not removed from the core by the emulsifying action of the outer soap layer.
The follo~Ying fa-tty acids or mixtures thereof are suitable.
Number of Approximate Carbon Atoms MeltinF Point, 0~
Lauric Acid 12 111 ~` 20 Myristic Acid 14 136 Palmitic Acid 16 147 Stearic Acid 18 157 Arachidic Acid 20 169 Specific mixtures of saturated fatt~ acids suitable for use in the practice o~ the invention are set forth in the follo~ing list.

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Technical rypical Chain-Length Distribution Appro~imate Desi~nation Percent ~leltl~g Point C10 C12 ~1~ C16 C18 ~0 90% lauric 491 ~ 1 104 95% :la-lric 1 95 4 109 99% lauric 0.3 990.7 111 95% myristic 295 3 127 9~/o palmitic 1 92 7 140 95% stearic 0.5 97 2.5 154 Triple~pressed stearic 2 52 46 131 Palmitic-stearic 8 75 17 131 Stearic - 5 30 65 139 The second coating is a water-soluble salt, for ~ `
example a sodium, potassium, ammonium or calcium salt of ; the fatty acid which comprises the first coating.
~en carrying out the process of the present invention, the first coating is conveniently applied by means ofthe apparatus shown schematically in Figure l. ~-Referring to the drawings, reference character 1 indicates a chamber or cylindrical tower, wherein the coating or - encapsulation of the particles is accomplished. ~t the base of tower 1 is a supporting,screen 2. The tower is fitted with a manifold inlet for the introduction of tangential air shown at 4. Shown at 3 is an unexpanded bed of the particles to be coated. A downwardly proJecting ~ ~
nozzle constituting a spraying means 5 is disposed within ~`
the tower 1.
- 30 The coating solution is contained in vessel 6 and is fed to nozzle 5 by pump 7. The spraying of the coating solution from nozzle 5 is aided by pressurized air ~ c B.358 ~05~311 e~-terin~ tower 1 at 8. Fluidiæing ~as passes through duc-t 9 and is forcecl through the screen support by blower 10 and is either cooled by cooling sys-tem 13, or heated by heat exch~lger 11, i~ required, in order to maintain the fluidizinbr ~as within a critical temperature rangeO An exhaus t blo~er 12 removes solvent vapors.
The fluidizing air velocity is controlled at an optimum for good fluidization. Too low a velocity will result in poor particle circulation and hence a poor coating.
Too high a velocity will promote mechanical breakdown of the particles and excessive particle carryover from the body of the bed.
The temperature of the fluidizing air, and hence ; the -temperature of the bed, is controlled within a critical range. Too low a temperature results in too low a rate of solvent evaporation to cause the particles to become too wet, circulate poorly, and agglomerate~ Too high a temperature tends to evaporate the solvent prematurely hefore the coating solution contacts the particle to be coated.- Normaliy the -temperature of the fluidizing air is such that the bed ` temperature is about 80F to about 130F.
` Particles coated by the above-described procedure are substantially completely co~ered with a continuous coating, and are free-flowing and non-agglomerated. ;
It is important that each bleaching agent particle be fully covered before treatment with an alkali hydroxide, since contact thereof with a chlorinated compound may result in a violent reaction.
After removing the fatty acid-coated particles ; 30 from the fluidizer, the particles are treated to appiy an ~ -~
outer coating of the water-soluble salt of the fatty acid c B.35~
ll)S~3~

~hich comprises the first coat. The outer COatLng is aclvantageously appl:ied by gently agita-ting the fatty acid coated particles in ~or example an aqueous solution of an alkali metal or alkaline e~th hydroxide having a concen-tration as set forth hereina~ter, for about 10 minute~ to about 2 hours, preferably for about -~ hour, and until the hydroxide reacts with a-t least a portion of the fatty acid, and completely coats the particles with the reaction product of the fatty acid and the hydroxide.
The temperature of the hydroxide solution is suitably between about 35F and about 200F and is not higher than the melting point, and preferably not higher than about 5F below the melting poin-t, of the particular fatty acid employed for the firs-t coat, and in any event not sufficiently high to melt the fatty acid. ~`
Following the aforementioned treatment the double `
coated particles are separated from the treating solution for example by decantation on a screen, and dried to produce completely coated, free-flowing, particles coated with a first or inner layer of fatty acid, and a second or outer layer of the fixed alkali soap of the fatty acid~
~en the alkali is sodlum hydroxide its concen-tration should be between about~% to about 10% by weight when the primary coating is stearic acid or a mixt~re of stearic and palmitic acids, and should be about 10~ to about 15% when the primary coating is lauric acid or the commercial 95% material. The concentration of potassium i hydroxide should be between about 10% and about 15%. ~ `~
` Calcium hydroxide should be applied as a saturated solution, ~ ~;
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i.e., about 0.1% by weight. `~-~ ;~
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~- c B.358 3~L1 Coa-ted particles of orgc~lic chlorine bleaching agent prepared in accordcmce ~ith the instant invention find utility in admixtllre with particula-te detergent compositions having therein an anionic or nonionic d~tergent species that is not adversely affected by chlorine liberated from the bleaching agent.
Suitable anionic detergents are primary and secondary alkyl sulphates, such as sodium and potassium l~uryl sulphate, alkyl benzene sulphonates such as sodium dodecylben~ene sulphonate and soaps.
Suitable nonionic detergents are the ethylene ; and propylene oxide condensates of primary and secondary aliphatic alcohols and mixtures thereof having about 8 to about 16 carbon atoms in the alcohol chain, the proportion of ethylene and propylene oxide being from about 50 to ~o by weight of the material. Similar condensates of alkyl-phenols are also suitable.
Further details of these conventional detergent lngredients can be ohtained from standard text books a~d from manufacturers' trade literature.
Preferably the detergent composition should be substantially free of compounds containing amino nitrogen to avoid adverse effects during~the washing operation.
The compositions containing coated bleaching ; 25 agents may be formulated with a detergent builder as a detergency ald, for example those mentioned hereinafter, to provide a commercially valllable deterge~t-bleach composition.
Suitable builder compounds are tetrasodium and tetrapotassium pyrophosphate, pentasodium and penta-~ potassium tripolyphosphate, sodium or potassium carbonate, : _ g _ /............................ ;~' . ....... . . . ... . . .. ...

~ ~.35~ -sodium or potassium silicates having an SiO2 : Na20 ratio o abou-t 1 1 to about 3.2:1, hydrated or anhydrous borax, sodiurn or potassium sestluicarbonate, polyphosphonates such as sodium or potassium ethane-l-hydroxy-l, l-diphosphonate, ~tc.
Also useful are the organic detergent builders which have been proposed recently in order to reduce the level o phosphate in detergents. These include sodium or potassium oxydisuccinates, carboxymethyloxysuccinates, and ester-linked carboxylate derivatives of polysaccharides, such as the sodium and potassium starch maleates, s$arch and oxidized heteropolymeric polysaccharides.
The weight percent of the builder present in the built anionic deter~ent composition is from an amount of about 6% and up to about 90% and preferabl~ from abou1t 2~b to about 6~/o. Suitably, a builder may be present in the ratios of about 0.5 to about 10 parts by weight, preferably ` about 2 to about 5 parts by weight, fQr each part by weight - of the detergent component.
Other conventional materials may be present in the detergent compositions of the inven$ion.- Typical ~ `
examples include the well-known soilsuspending agents, corrosion inhibitors, dyes, perfumes, fillers, optical brighteners, enzymes, germicides and anti-tarnishing agents.
The balance of the detergent composition may be water.
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Detergent compositions formulated for use in the washing of fabrics in automatic washing machines ma~ contain ~-about 5% to about 30% anionic de-tergent, about 30% to about ~ -~
60% of one or more of the builders mentioned hereinabove, and suficient coated bleaching agent to provide 30-200 parts per million chlorine in the wash water, or - '- ' :

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approximat~ly 2% to 25% of the agent in the detergent forlllulation. UsuaLly included are about 0.1-0.3~ optical brighte~ner, nnd abou-t 0.4% sodium sul~ate, and if desired small proportions of other components such as germicides, and ~ti-caking agents to confer specinl properties on the pro duc t .
~en the detergent is soap, ancl comprises the major proportion oE the detergent-bleach product, the soap may be pre,sent in amounts from about 6~/o to about 9~/o, little or no builder being required, although about 1% to about l~/o of an alkaline builder may be advantageous.
~en the detergent is nonionic, from about 5% to about 2~/o is suitable, the balance of the composition being as listed above.
;~ 15 Detergent compositions ~ormulated for mechanical i dishwashers and having the coated bleaching agents of the - invention therein may contain low proportions of nonionic detergent, for example about 1% to about 4%, and may contain ~` - a suds dapressant and a high proportion of a builde~, for example about 5~/~9~/o of a mixture of sodium tripoly-phosphate, sodium carbonate, and sodium silicate.
The invention is further illustrated in the following examples~ æ
Example 1 This example describes a process for coating -. .. ~
potassium dichloroisocyanurate wit~ a double coating.
Thirteen pounds o extra coarse grade potassium dichloroisocyanurate are charged onto the perforated plate of the cylindrical coating tower 1 (Figure 1). The ;~
; 30 perforated plate is a 60-mesh stainless steel sereen. The ~ .
particles are fluidiæed and suspended by an upwardly moving ~ '3 ~ ' ' ~ -' ' . ' . . , - ' ' . ', : ' ' ' ,' ' : ' ' ~ :

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air strealn supplied by blower 10. The superficial air velocity of the fluidirlg air stream is 8,5 feet per second.
The temperat-lre of -the air is maintained at 95 ~ 2~, by heat exchan~er 11.
The primary coating solution is prepared by dissolving triple-pressed stearic acid (about ~5% stearic acid) in methylene chloride to form a 2~/o solution. A small amount of ultramarine blue is dissolved in the coating solution for subsequent use in observing the eontinuity of the primary coating.
The primary coating solution is sprayed on the fluidized particles 3, through nozzle 5, appropriately adjusted as to height, Nozzle 5 has six orifices disposed to provide a diverging spray patternO An auxiliary stream of air is applied to the fluidized bed through 9 nozzles horizontally disposed at the perforated support screen level with the tips of the nozzles placed close to the inner wall :: .
of the to~er. The air leaves these nozzles in a horizontal ~ ~
path substantially tangential to the wall of the tower. It ~ --, 20 is the function of this tangentlal air to assist in keeping ~ -în motlon the particles at the outer periphery of the plate which do not obtain the full effect of the fluidizing air~
The coating solution is applied to the fluidized particles for a period of 2 hours. m e weight of the coating is about equal to the weight of the original particles. The coated particles are of uniform blue color and si~e, with substantially no agglomeration, and are dry and free-flowing, l~hen some of the coated particles are left immersed for 2 days in an acidified potassium iodide solution, no color change is observed, indicating complete encapsulation of ~ , . .
the particles~

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Ttle second coating is applied :in the followi~g manner.
A 5.2% sodium hydroxide solution is prepared by cliluting 60 grams of 5~/o NaOH solut:ion with 520 grams of distilled ~ater in a two-litre beaker. The dilute solution is heated to llOF in a ~ater bath and 200 grams of the particles coatecl as described above are placed in the NaOH
solutioll and gently agitated for 30 minutes, maintaining the temperature of the solution between 105F and 110F. The molar ratio of NaOH to fatty acid is 2~ fter the 30 minute treatment, the solution is decanted through a 25-mesh stainless steel screen, and the particles on the screen are dried at room temperature for 2~ hours. The particles are free flowing and white, indicating complete covering of the blue-colored first coat.
The single- and double-coated particles are tested for ease of chlorine release and for adverse effect on cloth in the follo~ing manner~
Six pounds of white cotton fabric are placed in a top~loading automatic washing machi~e. Three swatches of blue denim cloth and one swatch of black 65/35 Dacron~/cotton - cloth, each measuring 12 x 12 inches are placed on top of the cotton cloth in circular configuration. Next, there i~ placed-directly on the fabric 3.~ ounce,s of a detergent-bleach composition containing 8.0% of the coated material prepared as above. Water at a temperature of 132F ~ 3F is ~ ~
run directly on the detergent-bleach composition for about ~ ~ ~ s 150 seconds to a volume of 17.4 gallons. The wash solution is agitated for 10 minutes, and the fabrics are examined. The results are shown in Table 1.

* 'DACRON' is a registered trade mark.

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. , ~!, Bleach Composition % Pinholing %*KDC Coated With Available (Blue Chlorine C~lorine _ Denim) Releas~d Sin~rle Coat with ~atty Acid Fatty Acid (A) 35.0 3 97-100 " " (B~ 37.5 0 20 " " (C,)" 39.0 1 41.5 DUAI C~at rir~t Coat _ tty Acid (A)

2.85% NaOH 21.03 10 min. 2 not determined -~
5 34% NaOH 23.19 1 69.83 lS 10.33% NaOH 26.15 1 87.70 ,' (A) about 405% s~earic acid and 55% palmitic acid; m.p. ,'~

(B) 95% pal~tic, 4% stearic~ 1% myrlstic acids; m.p.

(C) about 70~oO tearic acid and 30% palmitic acid; m.p.
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Pinholin~_Ratin~ , O = none (excellent) 1 = minimàl pinholing (acceptable) 2 = severe " (unacceptable~

3 = very severe pinholing (unacc~,eptable) , * Potassium dichloroisocyanurate ~ ' , '-~ :' .' From the foregoing data in Table 1, it may be seen .
'~, that a single coating of fatty acid is inadequate to accomplish the dual purpose o~ providing a high chlorine release and at ~` the same time avoid pinholing. It will be noted that fatty .

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ac:id (A) having a melting po.int below the temperature of the wash ~atcr, melts to release all O:r the chlorine in the coated bleaching a~ent but causes pinholing~ clue to contact with the .~abric upon the~ meltin~ of the fat-ty acid coa-tin~. Fntty ac:icls (B) antl tc), having melt:ing points above the temperature of the wash ~ater, are unsatis.Eactory, since they do not allow a sufficient release of chlorine to be of any value as a bleach7 although the low level of chlor.ine release prevents pinholing~
Again referring to the oregoing data, it will be observed that a double coating applied in accordance with the .invention pre~ents pinholing to a subst~ntial extent, and additionally allows an adequate release of chlorine.
.; ' Example 2 This example further illustrates the present process for applying a first coating of fatty acid to particles of " potassium dichloroisocyanurate.
A coating solution is prepared in vessel 6 by dissolving 10 pounds of fatty acid (about 70% stearic acid and 30% palmitic acid~ in 40 pounds of methylene chloride. Twenty grams of blue pigment is added and the solution warmed at 95F.
Ten pounds of extra coarse grade potassium di.chloro-isocyanurate is screened to 25 mesh and placed on the 40-mesh supporting screen in coating tower 1 (Figure 1). Fluidizing air is forced into the apparatus through duct 9 at a superficial air velocity of 6.8 feet per second. Tangential air is supplied as neeclecl. The tempera-ture of the bed is maintained at 107 + 2~.

~, ' , , _ 15 -. : , , c B.358 ~43~1 The coatin~ solution is sprayed downward onto the `Luidized bed through a 6-hole atomi~ing no~zle located 12 inches above the supportin~ screen. The coatin~ is applied ~It the rate of 6.7 pounds per hour, and the solvent is evnporated at the rate of 23 pounds per hour.
I'he co~ted product is a dry, nonagglomerated, free-flowin~ particulate solid of which the particles are substc~ntially uniform in size. A test in po~assium iodide solution indicates that the par-ticles are completely covered.
After storing for 8 weeks at 80F and 80% relative humidity admixed with particles of a commercial detergent, ; substantially no loss of chlorine occurs. In a control experiment in ~hich the potassium dichloroisocyc~urate is uncoated, it loses 90/o of its chlorine.

Example 3 A spray-dried detergent composition having the following formula is prepared by conventional procedures.
% Alkylben~enesulfonate - 10.0 ~-% Sodium tripolyphosphate 33.0 .: , . . ..
% Sodium silicate solids 6.0 (SiO2:Na20 = 2-4) % Optical brightener ~ 0.1 % Carboxymethylcellulose 0.3 % Water lOoO :~ :
% Sodium sulfa-te and miscellaneous 40.0 matter introduced with the components 100.0 - ,~

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To separate portions of the above-describe~
compositlons are mlxed various ~roportions~of thè product of F,~ample 1, the ~roportions being as follows.
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P~ ts By ~_ei~ht Example No. 3A 3B 3C 3D 3E
Spray-dried composition 80 8~ 88 92 96 Product of` ~xc~ple 1 20 16 12 ~
A composition suitable for use in mechanical dish-; washers and having the following formula is prepared by conventionaltechniques~
% Nonionic detergent(a) 2.0 % Sodium tripolyphosphate 2000 % Trisodium orthophosphate25.0 % Sodium metasilicate 13.0 % Water 10~0 % Double coated organic chlorine 30.0 bleaching agent _ ;
100.0 ,, (a) A condensate of a mixture of primary aliphatic ~ . ;
alcohols having about 12-15 carbon atoms with about 25% lower alkyl branching on the 2-carbon, and about 9 molar proportions of ethylene oxide~
- ' '` ~' ~' Example 5 This example shows the effect on stability of coated and uncoated chlorinated/cyanurates admixed with a detergent composition when stored variously in open wax-l~minated barrier cartons and in open and closed non-barrier cartons, i.e., allowing free or only partiallyrestricted passage of vapors.
Mixtures are prepared, stored and ~nalyze~ as `
` follows.
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E:ight parts by wei~ht of the double coated pot~ssium d.ichloroisocyc~nura-te prepc~red as described in ~xample 1 are admixed with 92 p~ts by weight o.f a spray-dried detergent composition havi.nO the .~ormula set out in Example 3 and S d:iv:ided to produce 3 equal batches of material (a-c). .'Ewo s:imilarly sized batches of ~mcoated potassium dichloroiso-c~an-~ate (.e and f).and one o.L potassium di.chloroisocyanurate d;.hydrate (d) were a:Lso prepared. The batches were stored.
~fter 2 ~eeks' storage at 80F and 80~/o relative humidity, the chlorine losses are determined. The protective action of the double coating as compared with uncoated particles of chlorine bleaching agent is evident from the data set forth below: ~:
'' E~ample Stora~e Time lS O Week 2 Weeks 5a % Chlorine 2.31 2.26 % Loss - 2.1 :~. n :
5b % Chlorine 2.28 2.21 % Loss - 3.1 -. .... .
5c % Chlorine 2. 29 2.28 ;~
% Loss ~ 0~4 `~
5d yO Chlorine . 2.09 00 96 . ~0 Loss - 54 5e % Chlorine .2.08 1.75 % Loss / - 15.9 5f % Chlorine 1.99 1. 86 % Loss - 6.5 :i , .

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Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Particles of an organic chlorine bleaching agent having a double coating, an inner layer consisting predominantly of at least one C12 to C20 saturated fatty acid having a melting point above about 105°F and an outer layer consisting pre-dominantly of a water-soluble salt thereof.

2. Particles as claimed in claim 1 wherein the chlorine bleaching agent is a mono-, di- or tri-chloroisocyanurate.

3. Particles as claimed in claim 2 wherein the chlorine bleaching agent is sodium or potassium trichloroisocyanurate.

4. Particles as claimed in claim 1, claim 2 or claim 3 having an average particle diameter of from 1.2 to 1.66 mm.

5. Particles as claimed in claim 1, claim 2 or claim 3 wherein the fatty acid is a mixture of stearic and palmitic acids having a melting point of about 130°F.

6. Particles as claimed in claim 1, claim 2 or claim 3 wherein the water-soluble salt of the fatty acid is a sodium or ammonium salt.

7. A particulate detergent composition comprising a detergent active compound and particles of a chlorine bleaching agent as claimed in claim 1, claim 2 or claim 3.