Note: Descriptions are shown in the official language in which they were submitted.
~7~L~ 7 c ~4 (R)
SOAP-E~CAPSU~ATED B~EACH P~RTICLE8
Th~ invention relate~ to coated halogen bleaah
particle~ and a method ~or bleaching sub~trates through
slow uniform release of a~tive halogenatin~ agent from
the particle~.
Particle~ containing oxidants for bleaching ~ub~trateæ
have been wldely di~clo~ed in the literature. Much
research ha~ focu~ed upon coating or encapsulating
chlorinating agent~, e.g. dichloroisocyanurates
granule~, to obtain delayed~ 810w relea~e of active
oxidant.
When used for cleaning clothe~ in automatic washing
machines, several problems ar~ noted wi~h encapsula~a
oxidant~. Low bleaching ~trength i8 encountered becau3e
of incomplete dis olution of the encap~ul.ates during
the ~tandard wa~h cycle. Another proble~ i~ ~evere
fabric colour damage from the localization of released
bleach. Generally, bleaching products are placed into
the automatic washing machine simul~aneously with the
dry load. Bleach and fabric remain in close contact as
the machine fill~ with water. Local high concentration3
of bleaahing activee th~reby come into contac~ with
fabric surfaces. Under these condition~, very small
spot~ re~embling pinholes appear on the fabric.
U.S. Patent 4,136,052 ~Mazzola) report~ to have solvad
the pinhole problem cau~ed by locali3ed high
concentrations of bleach. The patent provide~ a 3pecial
coating which encapsulate~ the bleaching compound. An
active chlorinating agent i8 ~urrou~d~d by a ~ir~t non-
reactive coating combination o~ fatty acid and wax. A
second time controlled coating ia applied containing
fatty ac~d with a material e~hibiting inver~e aqueou~
301ubility with re~pect to tempera~ure. The outer,
~ ,.
~econd coating i~ more re~istant to di~olution in hot
than in cold water. By thi~ meanq, ~ufficient dqlay~d
release is provi~ed in hot water to prevent pinholing.
U.S. Paten~ 3,908,045 (Alterman et al.) di~closes
dichloroisocyanurate ~alt~ encapsulated wi~h a firRt
coating of a saturated fatty acid ~urrounded by a
second coating of ~oap. The latter coating is formed by
trea~ment of portions of the inner fatty acid coating
with a solution of an alkali met~l hydroxide.
The prior art compositions of soap-coated chlorine
bleach provide adequate protection again~t pinhole type
fabric damage only at low and medium wa~h temperatur23.
Unfortunately~ at hot wash temperature6, pinholing i~
still a problem. ~ ha~ been sugge~ted ~hat hot water
pinholing results from non-uniorm coating, fabric
damage b~ing caused by the inadequately encapsulated
particle fraction~. Uniformly coated particle6 have, so
far, been unobtainable. To solve.the problem, average
coating weights have been increa~ed by a~ much as 50%
over the known art. Even these increaaed ~hickne~3es do
not en~ure complete absence o~ pinholing at hot wash
temperature~. Very thick coating6, which do control
pinholing, are deficient because they hinder chlorine
release at low temperatures and afford no bleaching.
Con~equently, it i8 an object of the pre~ent invention
to provide bleach particles which eliminate pinholing
yet have satisfactory active halogen release at all
wash temperature~.
A further object of thi~ invention is to provide bleach
particles that do not relea~e active halogen oxidant
during the water fill cycle of an automatic w~ching
machine but ~ubsequently completely relea~e active
oxidant within the wash cycle~
C 6024 (R)
3~7
Another object of this invention is to provide a method
for bleaching a variety o flexible or hard-~urfaced
substrates.
Hard spherical bleaching particle~ are provided who~e
composition is an intimately dispersed agglomerated
mixture comprising:
(i) rom about 1 to 80% by weight of an oxidizing
material having at least one reactive chlorine or
bromine in its molecular structure;
(ii) from about 1 to 80% o~ an inorganic diluent salt;
(iii) from about 0,5 to 60% of a binder with melting
point 85 to 120F~ and
(iv) from about 5 to 50% of a coating covering a core
mixtur0 of elements (i) through (iii) consisting
essentially of a mixture of from about 70 to about 85%
alkali metal C16-C18 fatty acid soap and from about
15 to about 30% C12-C14 alkali metal fatty acid
soap.
The present invention report~ improved coatings to
encap~ulate core particles containing active halogen
oxidi~ing agents. ~ncapsulation using a blend of fatty
acid soaps of proper chain length has been found
critical in guarding against pinhole damage whila still
maximizing dis~olution rates to adequately relea~e the
oxidi~ing agent. The effective soap blend comprises a
mixture of coconut C12-C14 chain length fatty acids
llow C16 C18 chain length fatty acids An
increase in the coconut soap content of the coating
increase~ the dissolution rate. Too much coconut soap,
however, results in more pinhole damage. High tallow
soap levels inhibit relea~e of oxidizing agent from the
~ 7 C 6024 (R)
core when particles are di~per~ed in water; bleaching
is thereby adver~ely affected. Conseqllen-tly, it is
impor-tant to combina both types of ~oap to achieve a
coating accentuating the advantages o~ each of the
components.
The ^~oap coating may be applied to the core material at
a level from about 5~ to about 50~ by weight of the
particle; prefe~ably from about 20~ to 40~; rnore
preferably from about 25% to 35%. A coating of
approximately 30 wt.% soap provides sufficient
insulation thickness to adequately overcome pinhole
damage~ Substantially higher coating weights are
wasteful. They only serve to inhibi~ early chlorine
release during the wash cycle. Too little coating, of
course, would relea~e oxidant too rapidly.
Among the coconut type soaps useful for this invention
are the alkali metal, alkaline earth metal, a~monium,
Cl-C12 alkyl ammonium and Cl-C6 mono-, di- or
trialkanol ammonium salts of coconut fatty acid.
Coconut oil employed to prepare the soap may be
obtained synthetically or from ropical nut oils
including: palm kernel oil, babassu oil, ouricuri oil,
tucum, oil, cohune nut oil, murumuru oil, jaboty ksrnel
oil, khakan kernel oil, dika nut oil and ucuhuba
butter.
Tallow soaps include the alkali metal, alkaline earth
metal, ammonium, Cl-C12 alkyl ammonium and Cl-
C6 mono-, di- or trialkanol ammonium ~alt~ of C16-
Cl8 fatty acids. Rich ~ources of these fatty acids
are beef tallow, lard, olive oil and shea nut oil.
The soap~ may contain ~ome unsaturation; however,
substantial unsaturation is to be avoided. Active
halogen could be reactive with the unsaturated fatty
C 6024 (R)
~ ~;73417
acid soap. Sodium ~alts of the foregoing tallow and
coconut fatty acid~ are particularly preerred.
The core material of the bleach particles i~ a granule
comprising an oxidizing material, an inorganic diluent
salt and a binder with melting point 85-120F.
Oxidizing material is, to a sub3tantial extent,
hindered in release of active oxidizing agent by its
dispersal in the diluent inorganic salt/binder matrix.
There are, however, ~till surfaces where the oxidant is
exposed and readily available for release.
The coating of the present invention, when combined
with the core granule, improves control over oxidant
release. The soap blend coating of this invention
effectively retards release of oxidant during the fill
cycle of most automatic washing machines. Dissolution
rate of the coating varies little wi~hin the
temperature range of 70 to 135F, the range of common
wash temperatures. Good chlorine release
characteristics are observed at all common wash
temperatures during the wash cycle interval. The soap
blend is also unreactive toward the oxidant; the blend
provides a shield against oxidant 1055 during storage
of encap3ulated particles in detergent powder. With a
protective coating of about 25-30~ by weight of the
total particle, pinhole damage is prevented during the
typical 4-minute washing machine fill cycle, even at
high wa~h temperatures. Thereafter, particles dissolve
rapidly during the agitation wash cycle. ~igh levels of
bleaching agent are therefore available through most of
the wash cycle.
The oxidizing material is one having at least a
reactive chlorine or bromine atom in its molecular
~tructure. Among the suitable halogen donor bleaches
are heterocyclic N-bromo and N~chloro imides such as
~7~7 c 6024 (R)
-trichlorocyanuric, tribromocyanuric, dibromocyanuric
and dichlorocyanuric acids, and salt~ thereof with
water-solubilizing cations such as potas~ium and
sodium.
Other N-bromo and N-chloro imides may also be u~ed such
as N-brominated and N-chlorinated succinimide,
malonimide, phthalimide and naphthalimide. Other
compounds include the hydantoins, such as 1,3-dibromo-
and 1,3-dichloro-5,5-dimethylhydantoin, N-monochloro-
C,C-dimethylhydantoin methylene-bis(~-bromo-C,C-
dimethylhydantoin); 1,3-dibromo- and 1,3-dichloro-5-
isobutylhydantoin; 1,3-bromo- and 1,3-dichloro-5-
methyl-5-ethylhydantoin; 1,3-dibromo- and 1,3-dichloro-
5,5-isobutylhydantoin, 1,3-dibromo- and 1,3-dichloro-5-
methyl-5-n-amylhydantoin, and the li~e. Further useful
hypohalite-liberating agents comprise tribromomelamine
and trichloromelamine.
Dry, particulate, water-qoluble anhydrous inorganic
salts are likewise suitable for use herein, such as
lithium, sodium or calci~ hypochlorite and
hypobromite.
The hypohalite-liberating agent may, if desired, be
provided in the form of a stable solid complex or
hydrate. Examples include sodium p~toluene-sulpho-
bromoamine trihydrate, sodium benzene-sulpho-chloramine
dihydrate, calcium hypobromite tetrahydrate, calcium
hypochlorite tetrahydrate, etc. Brominated ~nd
chlorinated trisodium phosphate formed by the reaction
of the corresponding sodium hypohalite solution with
trisodium phosphate (and water if necessary~, likewise
comprise efficacious materials.
Sodium dichloroisocyanurate is, however, the preferred
bleaching source because of its great water solubility,
~734~ C 6024 (~)
high chlorine content and dry storage stability when
combined with -the other core components. Although it
could be used, calcium hypochlorite i5 more reactive
and tends to lose chlorine activity during storage.
Coarse grade sodium dichloroisocyanurate is used 80
that there i~ a high recovery of propar mesh ~ize
particles. Thi9 material is commercially available
under the trademark Clearon CDB, ~ product of the FMC
Corpora~ion.
- 10
Bleaching agents may be employed in admixtures
comprising two or more distinct chlorine donors. An
example of a commercial mixed æy t~m i8 one available
from the Monsanto Chemical Company under the trademark
designation "ACL-66" (ACL signifying "available
chlorine" and the numerical de~Rignation "66" indicating
the parts per pound of available chlorine). The
material comprises a mixture of potassium
dichloroisocyanurate (4 parts) and trichloroisocyanurate
acid ~1 part).
By th0 term "reactive chlorine or bromine" is meant any
o~idant capable of releasing halogen in the form of
free elemental chlorine or bromine under conditions
normally used for detergent bleaching purposes. It must
also be understood that the hard spherical bleaching
particles of this invention are not limite to their
utility for washing fabric. They may also be used on
dentures, floor~ and a variety of other hard or soft
surfaces requiring cleaning with a controlled release
oxidant.
In addition to the aforedescribed halogen-containing
oxidan~s, there are numerou~ other Rimilar materials
well known in the art. The li~t is by no means
exhaustive. For instanee, suitable chlorine-releaqing
agents are also disclosed in ~he ACS monogram entitled
~ 7347 ~ 6024 tR)
"Chlorine - Its Manuacture, Properties and Uses" by
Sconce, published by Reinhold in 1962.
When utilizing the particles of this invention in a
detergent formulation, the desired chlorine level in a
wash solution is about 10 to about 200 parts per
million available chlorine. Preferably, the range i8
about 15 to 50 ppm for the most efficient utilization
of chlorine-containing material as a brightener to be
used with coloured clothes. The6e levels determine the
amount of bleach particles which must be incorporated
into a detergent formulation.
Anywhere from about 1 to 90% by weight of the total
particle may be halogen-containin~ oxidizing material.
Preferably from about 30 to 70%, more preferably from
about 40 to 60% of oxidizing material is present.
A n.lmber of different inorganic salts may be employed
as the diluent. Examples include borates, nitrates,
orthophosphates, tripolyphosphates, silicate~,
sulphates, zeolites and clays. Sodium salts of the
foregoing diluents are preferred. ~hese salts must be
inert to oxidation. Sodium tripolyphosphate is an
especially preferred diluent for the core granule. The
inorganic salt diluent may be present in an amount from
about 1 to 80~ by weight of the total granule.
Preferably, it should be present in an amoun-t from
about 10 to 60~.
A third essential element is a binder with a melting
point between 85 to 100F. Lauric acid is the binder
of choice. It softens at common, low wash temperatures;
yet, it is still solid at room temperature. Higher
chain fatty acids do not release bound chlorine at low
wash temperatures. Fatty acids with lower melting
points do not keep the particles firm during subsequent
1267~47 C 6024 (R)
fluidization and encap-Rulating processing.
DichloroiRocyanurate is also stable when in contact
with lauric acid during long period~ of ~torage.
S A particularly preferred binder i8 Emery 651, a product
of the Emsry Chemical Company, a Division of ~ational
Distillers Corporation. Emery 651 contains g6% lauric
acid and 3% myristic acid; the melting point of this
material is 106-lO9~F.
Suitable binders may also be found among organic
homopolymers and copolymers. An example of a auitable
homopolymer is polyvinylpyrrolidone.
A preferred embodiment of the core granules is one
comprising a combination of dichloroisocyanurate,
sodium tripolyphosphate and fat~y acid binder. When
these components are procesYed at temperature~ above
the fatty acid melting point, the surface tension of
the resultant mixture i~ sufficient to render the
granules spherical. No reaction occurs between the
aforementioned components.
Core material is typically prepared by combining a
bleaching agent Ruch as sodium dichloroisocyanurate
with sodium tripolyphosphate and lauric acid in a
rolling drum mixer. After brief mixing of components by
rotation of the drum, heated air is blown through the
compo~ition until a temperature is attained slightly
above the melting point of the fatty acid.
Agglomeration of the tripolyphosphate and fatty acid
binder around the dichloroisocyanurate granules is
thereby accomplished. A combination of surface tension
and action of the rotating drum cause6 the core
components to draw together into ~pherical particles.
These are then cooled. The particles are ~creened to
18-25 U~S. Mesh with abou~ 70~ recovery. Oversized
:~6~3'~'7
C 6024 ~R)
J0
agglomerates constitute the remaining 30%; these may be
ground and recycled baclc to the mixer. Diluted core
particles may be stored for subsequent encapsulation.
They are comple~ely stable under cool, dry storage
conditions.
Encapsulation of the diluted core granules with the
soap blend may be performed by a variety of methods. A
particularly praferred method is by the use of a
spouted fluidiæed bed apparatu~.
The soap blend is dissolved in water to provide a
solution of concentration from abo~t 5 to 40%;
preferably a soap solution of 15 to 304. Soap is then
sprayed ~hrough an atomizing nozzle onto fluidized core
granules held in the ~pout of the fluid bed. Water is
continuously removed by the action of hot fluidized air
passing through the bed. Bed temperatures are initially
kept at 10-15F below the melting point of the fatty
acid binder so that it will not melt and cause
agglomeration of the particles. Drying rates are
accordingly adjusted. Once the core granules have
received an approximate 10~ coating, temperatures are
increased to around 140F; thi3 permits an increased
rate of application of coating resùlting from increased
drying rates at the elevated temperatures. After the
targeted soap blend thickne3s has been applied, the
encap~ulates are fluidized for an additional 10-15
minutes to complete drying. A final water content of
around 7~ may still be present in the particles.
Storage stability is una~fected by this level of water.
If desired, additional coatingq may be applied to
envelope the prime coating of soap. For instance, the
additional coating may be selected rom a cellulose
material, organic homopolymPrs or copol~mer3, and
mixtures thereof. Suitable cellulose materials may
1~7~47 C 6024 (R)
11
include hydroxypropyl cellulose, hydroxypropylmethyl
cellulose, hydroxybutyl cellulose and carbox~methyl
cellulose. Examples of copolymer~ that may be employed
include styrene-maleic monoalkyl e~ter~, ~tyrene-
acrylic copolymers, maleic anhydride-acrylic and
acrylic-methacrylic copolymer~. EIomopolymers may
include poly~tyrene, polyacryla~e, polymethacrylate and
polyvinylpyrrolidone.
Bleach particles of the present invention may be
incorporated into a detergent composition containing
surfactants, soaps, builder~, enzymes, filler materials
and other minor functional laundering agents commonly
found in such compo~itions.
1~
Surfactants present in the~e détergent composition~ may
be found in an amount from about 2~ to 50~ by weight,
preferably from 5 to 30% by weight. These surfactants
may be anionic, nonionic, zwitterionic, amphoteric,
cationic or mixtures thereof.
Among the anionic surfactants are water-soluble salts
of alkylbenzene sulphonate~, alkyl ~ulphate~, alkyl
e-ther ~ulphates, paraffin sulphonates, alpha-olefin
sulphonates, alpha-sulphocarboxylates and their e~ters,
alkyl glycerol ether sulphonates, fatty acid
monoglyceride sulphates and sulphonate~, alkyl phenol
polyethoxy ether sulphates~ 2-acyloxy-alkane-1-
sulphonates and beta-alkoxy alkane sulphonates.
Nonionic ~urfactants are wa~er-soluble compounds
produced by the condensation of ethylene oxide with a
hydrophobic compound ~uch a~ an alkanol, alkylphenol,
polypropoxy glycol or polypropoxy ethylene diamine.
Example~ of nonionic surfactant ar~ the conden~ation
products o ethylene o~ide, propylene oxide and/or
blatylene oxide with C8-C18 alkyl phenols, C8-
C 6024 (R)
~7~7
12
C18 primary or secondary aliphatlc alcohols, C8-
C18 fatty acid amides. The average moleR of ethylene
oxide and/or propylene oxide present in the above
nonionics varies from 1 to 30; mixtures of variou~
nonionics, including mixtures of nonionic~ with a lower
and a higher degree of alkoxylation may al~o be used.
Cationic surfactants inalude the quaternary ammonium
compounds having one or two hydrophobic groups with 8-
20 carbon atoms, e.g. cetyl trimethylammonium halide ormethosulphate; dioctadecyl dimethylammonium halide or
methosulphate: and the fatty alkyl amine~.
Zwitterionic surfactants are water-soluble derivatives
of aliphatic quaternary ammonium, pho~phonium and
sulphonium cationic compound~ in which the aliphatic
moieties can be straight or branched, and wherein one
of the aliphatic sub~tituents contains from about 8 to
18 carbon atoms and one contains an anionic water-
solubili2ing group. ~xamples are alkyl dimethylpropane-sulphonate~ and alkyl dimethyl
ammoniohydroxypropane-sulphonates wherein the alkyl
group in both types contains from about 1 to 18 carbon
atom~.
Conventional alkaline detergency builders, inoryanic or
organic, may be found in these composi~ions at levels
from about 2 to 80%, preferably from 10 to 50% by
welght. Inorganic builders include water-soluble alkali
metal phosphateq, polyphosphate~, borateæ, sllicates
and carbonates. Organic builders include: (1) water-
soluble amino polycarboxylate3, e.g. ~odium or
pota~sium ethylene diamine tetraaaetates,
nitrilotriacetates and N-(2-hydroxy) ethyl
nitrilodiacetate~; (2) water-~oluble ~alts of phytic
acid; (3) water-~oluble polyphoqphonate3 such as salts
of ethane-l-hydroxy-l,l-diphosphonic acld; methylene
~67~34~ C 6024 (R)
diphosphonic acid ~alts, ethylene dipho~phonic acid
salts and ethane-1,1,2-triphosphonic acid ~alt~; (4)
water-soluble ~alts of poLycarboxylate polymers and
copolymers. Certain aluminosilicates such as synthetic
zeolite~ can al~o be u~ed.
Adjunct materials commonly used in detergent
compositions may be incorporated. These include 80il-
suspending agents such as water-soluble salts of
carboxymethyl cellulose, copolymers o maleic anhydride
with vinyl ethers, and alkyl or hydroxyalkyl cellulo~e
ethers. Other adjuncts include colorants, perfumes,
lather boosters, anti-foam agents, optical brighteners,
anti-oxidants and anti-corrosion inhibitors.
The following examples will more fully illustra~e the
embodiments of the invention. All parts, percentages
and proportions referred to herein and in the appended
claims are by weight unless otherwise indicated.
73~ 7 C 6024 (R)
14
Example 1
Preparation of Core Granules
Core particles were found to be best prepared by a
rolling drum process. This ~ethod provides strong,
coherent core particles capable of withstanding a
subsequent coating operation in a ~luid bed. The
process involves pa~sing heated air (about 85 to
lS0F) through a rolling drum ~illed with a mixture of
granular halogen bleaching agent, inorganic salt
diluent and a low-melting fatty acid (binder). A8 the
fatty acid melts, it combines with the inorganic salt
to intimately enca~e the chlorinat.ing agent. A nearly
spherical core agglomerate i8 thereby created. Specific
detail3 of ~he process are hereinater described.
A 4-foot long, 2-foot diameter rolling drum mixer was
employed for the agglomeration. The drum was fitted
with 6 inch spiral baf~les to promote better mixing. A
small motor rotated the drum at 32.5 rpm. Core
particles were formea in batch runs of 50 lb raw
material charge. Each charge con~isted of 35 lbs of
coarse or fine-coarse Clearon CDB granules, 10 lbs of
sodium tripolyphosphate and 5 lb~ of Emery 651 fatty
acids. The~e materials were thoroughly blended by
ro-tation of the drum for 10 minutes. Hot air was then
blown through ~he drum to heat the core mixture.
As the temperature rose to the melting point of the
fatty acids, the molten fatty acid mixture with sodium
tripolyphosphate formed a coating around the Clearon
CDB particles. After the reac~ant blend had reached
110F, it wa~ allowed to cool with continuing drum
rotation. Upon cooling~ there resulted hard, coherent,
nearly ~pherical particles. These particles were
screened to obtain si~es in the range o~ 18-25 U.S.
~6'73'~ C 602~
Standard Me~h with 30-70~ of theoret.ical recovery.
Mea~ured chlorine content of the core particle~ ranged
from 42 to 48~.
~
A 1.3 kilogram charge of core agglomerated granule~ was
placed in an Aeromatic S~rea-l Fluid Bed. A mixture of
tallow/coconut fatty acids of 80/20 ratio was dis~olved
at 75C in water to provide a 22~ solution. Core
granules were fluidized under agitation of an air flow
at 55 cfm held at 30C. The bed was well fluidiYed
under these conditions. Coating commenc~d by spraying
the soap solution onto the fluidi~ed core granules from
a spray nozzle located above the bed. Initially, the
~pray ra~e was held at 3 ml/min. This rate was
maintained for about 68 minutes; approximately 3 wt.%
of coating was achieved at this point known a the
"initial coating stage". Fluidization during thi~ and
~he ~ub~equent stage was di~icult due to the low
attainable drying rates. Subsaquently, the ~pray rate
could be increased to a maximum of 8 ml/min. at 30C.
During this stage, the coating thickne~s was sufficient
to completely cover the core granule surface. With the
contiguous coating, binder tackines~ was eliminated,
thereby improving fluidi~ation. The bed was operated at
the aforementioned spray rate for approximately 87
minute~ until a 10-12 wt.% soap coating had depo~ited;
this stage is termed the "low temperature coating
stage".
The coating was now thick enough to overcome meltlng
effects of fatty acid binder within the interior of the
encapsulate. Temperatures and ~pra~ rates could now
gradually be increased to 60~C and a maximum of 25
ml/min. Evaporation rates were greatly increa~ed owing
to the higher ~ed temperature. Fluidization a~ this
~73~7 C ~024 (R)
1~
point wa~ excellent. Operation of the bed undar these
condi~ions was continued for an additional 75 minutes.
The final coating reached 30 wt.~.
Further drying was performed at high temperature for an
additional 10 minutes. Total encapsulation time was
approximately 4 hours. Free-flowing encapsulated
particles were obtained having approximately 25~ active
chlorine. There was a 4~ active chlorine lo~ in the
process due to the interaction of water solvent with
the exposed core surface during the initial stage of
encapsulation.
Example 2
Pinhole ~est
Pinholing was evaluated by olacing the bleach particles
on denim cloth swatches for four minutes in wash water
held at specified temperatures. Denim cloth was used in
the test because the dark navy dyes in the cloth are
very susceptible to bleach damage. I'emperature used to
simulate actual wash conditions were: hot - 135F;
warm - 100F; cold - 70F. A~ter the bleach particles
had remained on the cloth underwater for 4 minutes in
an unagitated state, they were agitated for 1 minute.
Thereafter, th~ denim was removed from tha wash water,
rinsed and inspected for fabric dye damage. No effect
on the colouring of the denim cloths was designated as
excellent protection of the encapsulating coating.
Overall lightening of the cloth was designated as good.
Very light, localized BpotS wa~ designated as slight
pinholing. Appearance of very light, readily
distinguishable spots was designated as poor
protection. When the cloth turned brown and was
"burned" by the high chlorine concentration, this was
designated as very poor protection.
~7~47 C 6024 (R)
Chlorine Release Te~t
. . . _ . _
The~e tests were conducted by placing a small sample of
the bleached particles in a flask with wash water at
the wa~h temperature. The solution was gently agitated
for 4 minutes by slow turning of the flask in a
rotating ~lask apparatus. The treatment was intended to
simulate the fill cycle of a typical washing machine.
Subsequently, a ~ample of wash water was withdrawn and
titrated with sodium thiosulphate solution. Chlorine
content was established by this titration. The speed of
flask rotation was then increasea to simulate the
agitation cycle of a washing machine. At the 8, 12 and
16 minute marks, samples were withdrawn; the~e sample~
were titrated to establish ~hlorine content of the
solution at each point of the wash cycle. The r~maining
solution including any remaining parti¢les was then
titrated to establiæh the extent of unreleasea
chlorine. The test provides ~ reliable indica~ion of
chlorine release expected in the non-agitated fill
cycle and wash cycle of an automatic washing machine.
Performance of Encapsulated Bleach Granules
The composition~ of various base soaps are outlined in
Table I. Soap~ A through F are identifi d by the
content and nature of their fatty acid conæti~uents.
Coating weight percentages and the identity of the
soap(s) blend employed is listsd in Table II. Core
composition~ are identified in the footnote wherein
Na TPP refers to sodium tripolypho~phate and CDB refers
to Clearon CDB, the chlorinating agent.
Performance of the encapsulates is ~et ~orth in Table
III.
C 6024 (R)
~;7~
18
A blend of 6S~ coconut Soap F and 35% tallow Soap E
provided excellent chlorine release. However, the
particles encapsulated therein dis~olved 80 rapidly
that pinholing damage was considerable at 135F wash
temperatures. Coating of Soap B, consisting o a 40/60
blend of coconut and tallow soaps, also provided good
chlorine release. Pinhole damage, however, waa
unacceptable. Coatings of Soap A appear to have the
best dissolution prope~ties of the ~ncapsulates
evaluated. Chlorine release into the wash was good and
pinhole protection was maintained at all wash
temperatures. Soap A consists of a 20/80 blend of
coconut and tallow sodium soaps. Soap A of Sample 7 was
prepared by the aforedescribed encapsulation method,
except that water was replaced by acetone as the
processing solvent. Acetone-processed encapsulates
provided better performance than those processed with
water. Compare the 8 minute chlorine relea~e value in
Samples l and 7.
A further increase in tallow content reduced the
performance of the encapsulate. A lO/90 blend of
coconut and tallow sodi.um ~oaps (10% Soap F, 90~ Soap
E) provided pinhole protection. Unfortunately, the
encapsulated particles did not dissolve at low wash
temperatures (70F3, resulting in poor chlorine
release.
C 6024 (R)
1;~ 47
19
TABLE I
~ S ~ _ase Soa,~
- 5 Fatty Chain Soap Soap Soap Soap Soap Soap
Acid Length* A B C D E F
(Tallow) (Coconut)
Caprylic C8 1.2 2.7 - 6.8 - -
Capric C101.1 2.5 _ 6.3 _ 1.0
10 Lauric C129 7 20.3 1.0 4g.3 - 96.0
Myristic C14 5.0 9.3 3.2 18.5 2.5 3.0
Palmitic C16 22.6 19.0 2S.6 9.0 50.0
Margaric C17 1.0 0.7 1.2 _ 1.5
Stearie Cl~16.5 12.6 19.6 2.2 45.5
15 Palmit- Clç.l2.6 1.9 3.2 - _ - _
oleic
Oleic C18 1 34.7 27.0 41.0 6.1 - -
LinoleicC18:2 2.1 1.5 2.5
~ Chain lengths constituting les~ than 1~ are not shown.
C 6024 (R~
" ~2~7~3'~
~o
TABLE II
Encapsulate Coatin ~ anules
__
Sample Core
Encapsulate Com~osition Coa~in~
1 I 100% Soap A
2 I 65% Soap F, 35~ Soap E
3 I 10% Soap F, 90% Soap E
4 I 25% Soap F, 75%,
S II 100% Soap B
6 II 100~ Soap A
7 I 100% Soap A (acetone solven~
- . processed
I - 70% CDB; 20~ Na TPP, 10% Emery 651
II - 10~ CDB; 80% Na~S04; 10% Emersol 132
~ 7~347 C 6024 (R)
21
TABLE III
Pin-Percentage o~ Chlorine
Temper- holingRelea~ed
..
ature Per- Minute3
5 S~mple ~F) formance 4 81~ 16
1 70 Excellent 0 19.0 94.4 99.6
100 Excellent 0 90.1 100 100
135 Good 2.0 95.9 100 100
2 70 Good 0 84.6 98.7 100
100 Good
135 Very Poor
3 70 Excellent 0.9 0.9 0.9 4.2
100 Excellent - - - -
135 Excell.ent 0.5 55.9 84.3 100
4 70 Good 0 4.5 29.5 52.4
100 Good - . - -
135 Very Slight 7.2 96.3 g6.7 92.4
~ 5 70 Poor - - - -
100 Very Poor æ .0 31.6 59.0 84.1
135 Very Poor .- - - -
6 70 Good
100 Good 4.3 - 63.7
135 Very Slight 4.4 - 54.0
7 70 Excellent 0 45.1 89.9 96.6
100 Excellent - - - -
135 ~ood 2.7 98.5 99.3 100.0
Unencapsulated
35 Core I
.
8 70 Very Poor 12.2 58.7 87.2 96.4
100 Very Poor 100 100 100100
135 Very Poor 100 100 100100
~7;~47 C 6024 (R)
The forego.ing description and example~ illustra~e
selected embodiments of the present invention and in
light thereof various modifications will be 3ugge~ted
to one skilled in the art, all of which are within the
spirit and purview o this invention.
