Note: Descriptions are shown in the official language in which they were submitted.
WO 92/21744 PCI`/I,'S92/04500
2 1 ~ 8
DRY BLEACH COMPOSITION
WIT~ IMPROVED DISPERSIBILITY
Backaround of the Invention
1. Field of the Invention
10 This invention relates to dry fabric bleaching products
for household use, and more particularly to such dry bleach
products based upon peroxygen bleaches, which are formulated
to exhibit improved dispersibility/solubility in cold water.
2. Descri~tion of Related Art
Bleaching compositions have long been used in households
for the bleaching and cleaning of fabrics. Liquid bleaches
based upon hypochlorite chemical species have been used
extensively, as they are inexpensive, highly effective, easy
to produce, and stable. However, the advent of modern
synthetic dyes and the use of modern automatic laundering
machines have introduced new requirements in bleaching
techniques, and have created a need for other types of
bleaching compositions. In order to satisfy this need, and to
2, broaden and ~x~n tn~ u.~ f ; .e;~-r.es i`! ~r~,eao l..d US:,
other bleach systems have been introduced in recent years,
most notable are the peroxygen bleaches which generate
hydroperoxide ion as the oxidizing species. A particularly
preferred peroxygen bleach is sodium perborate which is
suitable for a dry granular formulation- Preferably sodium
perborate is combined with an alkalinity boo5terlbuilder such
as sodium carbonate and is used as a laundry additive. Such a
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WO92t21744 PCT/US92/04500
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laundry additive composition is more fully described in US
3,697,271 to Maddox, incorporated by reference herein.
s
While these compositions have a demonstrated effectiveness,
changes in laundering procedures often dictated by
environmental concerns, can reduce their effectiveness. Cold
water washes, for example, coupled with shortened wash cycles
may hamper solubility/dispersion of sodium perborate/sodium
carbonate formulations. Detergents or additives having high
sodi~m carbonate levels readily form bridged hydrated product
lumps when placed in piles and submerged in cold water. In a
washing machine, these lumps can not be broken apart by
l; agitation and leave residual product known as cold water
residue (CWR). When the bulk solution temperature is low
enough to cool the internal structure of the submerged pile
below the melting points of the carbonate hydrates,
precipitation of hydrates occurs in the saturated internal
pile spaces and a bridged CWR mass is formed. CWR has been
observed in the washer at temperatures as high as 75O~.
Approximately 25% of all U.S. washloads are conducted at or
below this temperature.
Several references have addressed the question of improving
cold water dissolution of laundry detergent compositions,
however, these limit themselves to compositions containing
detersive levels (above about 5%) of surfactant. Cala et al,
US 4,196,095, describes and claims a dry blended,
carbonate-based detergent comprising 30 to 90% of a builder
salt, at least one third of which is sodium carbonate; sodium
silicate; S to 30% of a surfactant, and O.1 to 2% of magnesium
stearate. The magnesium stearate is employed to reduce
insoluhle lumps formed when a detergent composition contacts
cold water. Nakamura_et _l, US 4,970,017, claims a process
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for producing a granular detergent composition having high
density and wherein one step of the claimed process comprises
coating a disintegrated granular detergent co~position with
0.5 to 5% by weight of a water-insoluble finely divided
powder.
JP 60-96698 (Hara et al), describes a method for manufacturing
a granular detergent composition wherein 0.S to 5 weight
percent of calcium stearate or other water insoluble powder is
added to a granulated detergent product specifically to
improve solubility in cold water. JP 62-228000 Saito et al,
describes and claims a high density granular detergent
lS composition, also employing a hydrophohic powder such as
calcium stearate, as a means of improving cold water
solubility. JP 64-20298 to Nakamura et al also describes and
claims a high density granular detergent composition having as
its object the attainment of a better cold water dissolution
rate. This application points out one of the disadvantages in
the use of hydrophobic fine powders to attain satisfactory
dissolution rates, that is, while the hydrophobicity of the
powder may aid dispersion, it can also impede dissolution.
Summarv of the Invention
It is therefore an object of the invention to provide a
dry peroxygen bleach formulation which exhibits minimal cold
water residue and retains good flowability and pour qualities.
It is also an object of the invention to provide a dry
peroxygen bleach formulation which is highly soluble in
aqueous media at low temperature.
Other objects and advantages of the invention will become
apparent from a review of the following description and the
claims appended hereto.
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Briefly, the present invention is a dry, fabric bleaching
composition comprising
(a) a bleaching-effective amount of a peroxygen
bleach;
(b) an alkaline builder material in an amount
sufficient to provide an alkaline pH and building
capacity;
(c) about 0.05-0.5% of a calcium stearate powder; and
(d) o to about 5% of a surfactant.
The laundry additive composition of the present invention
exhibits a dramatic reduction in cold water residue compared
with similar compositions of the art having no calcium
stearate powder. ~urprisingly, the improvement in cold water
residue does not result in a reduction in pour qualities or
flowabillty of the composition, nor are the dissolution
properties adversely affected.
A method of making the composition of the present invention is
also disclosed, and comprises dry blending the peroxygen
bleach and alkaline builder, as well as any other dry
ingredients. To this is added the calcium stearate powder
2 which is further blended until completely dispersed, uniformly
coating the other dry ingredients. Generally about 5-10
minutes in a tumble style mixer is required. Last, any
liquids, particularly nonaq~eous liquids such as surfactant,
are applied using a coarse spray, while contlnuing to mix, to
result in a uniformly coated dry mixture. Optimally, the
initial dry blending step may be replaced by an agglomeration
step wherein the oxidant and builder are coagglomerated with
an agglomerating agent.
If the agglomeration step option is utilized, it is preferred
that the builder be preloaded with a low level (less than
about S%) surfactant prior to agglomerating with the oxidant.
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escriDtion of the Drawinas
Fiqures 1 and 2 are graphs showing the effect on bulk solution
dissolution of various levels of calcium stearate powder (as
calcium stearate). T~e data were obtained using a sodiu~
perborate/sodium carbonate laundry additive matrix, and wash
conditions were a water temperature of 4.5~C, 100 ppm hardness
and five pounds of ballast. Results were obtained as
conductance (in millisiemenstcm).
Fig. 1 is a graph showing the effect of 0.25 weight percent of
calcium stearate on bulk solution dissolution compared to a
control having no calcium stearate; and
Fig. 2 is a graph showing the effect of 0.5 weight percent of
calcium stearate on bulk solution dissolution compared to the
same control.
Detailed DescriDtion of the Invention
Briefly, the present invention is a dry, fabric bleaching
composition comprising
2i (a) a bleachlng-effecti~e amoun; of a pei-oxygen
bleach;
(b) an alkaline builder material in an amount
sufficient to provide an alkaline pH and building
capacity;
(c) about 0.05-0.5~ of a calcium stearate powder; and
(d) 0 to about 5% of a surfactant.
A first method of making the composition of the present
invention is also disclosed, and comprises dry blending the
peroxygen bleach and alkaline bullder, as well as any other
dry ingredients. To this is added the calcium stearate powder
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which is further blended until completely dispersed, uniformly
coating the other dry ingredients. Generally about 5-10
minutes in a tumble style mixer is required. Last, any
liquids, particularly nonaqueous liquids such as surfactant,
are applied using a coarse spray, which continuing to mix, to
result in a unifor~ly coated dry mixture.
A second method of making the composition of the present
invention is an agglomeration process wherein the oxidant
material and alkaline builder are agglomerated prior to
addition of the calcium stearate powder. In this method, the
1~ alkaline builder is first preloaded with surfactant, and any
additional liquid additives. Thus surfactant is applied to
the builder in a mixer, preferably, a tumble-style or falling
curtain rotary mixer, and mixed sufficiently for the builder
to substantially absorb the surfactant. Sufficient surfactant
is applied to the builder to result in a final product (after
agglomeration) surfactant content of 0 to about 5 wt. %,
preferably about 0.1 - 3 wt.%. Generally on a surfactant to
builder weight basis about 0-20 wt. ~ surfactant is applied to
the builder, more preferably about 1- 15 wt. %. The preloaded
2~ builder and oxidant are then charged to the agglomerator. Any
agglomerating apparatus known to the art may be employed and
preferred are rotary or vertical turbo agglomerators.
Similarly, any agglomerating agent may be used, with sodium
silicate and polyacrylates preferred. The agglomerate is then
mixed with the calcium stearate powder and any additional dry
ingredients in a mixing means, especially a rotary or tumble
mixer.
In both processes, care must be taken to minimize physical
contact between the calcium stearate and the surfactant, in
order to ensure the efficacy of each component.
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Unless indicated to the contrary, all percentages, ratios, or
parts are determined by weight.
Bleach
Preferred as bleaches are peroxygen or peracid bleaches in
solid form. Preferred peroxygen bleaches include sodium
percarbonate, sodium perborate, sodium phosphate
peroxyhydrate, potassium permonosulfates and metal peroxides.
Sodium perborate is most preferred and may be in the form of
tetrahydrate or monohydrate. Bleach activators, also known as
peracid precursors, can be included with the peroxygen
compounds. Examples of activators include tetraacetyl
ethylenediamine (T~ED), nonanoyloxy benzene-sulfonate (NOBS),
and nonanoylglycoylphenol sulfonate (NOGPS). NOGPS is
disclosed, for example, in US patent 4,778,618 issued to Fonq
et aL and in E~ 373743 to Bolkan et al, the disclosures of
which are incorporated herein by reference. If added, the
peracid percursor is added in an amount effective to provide
oxidizing power, and generally in a mole ratio to oxidant
bleach of about 0.1:1 to 10:1. Peracid bleaches (including
monoperacids and diperacids) may be advantageous in terms of
~' bleacn_nq perrormar.ce. Examples include pera~e aic and
diperazelaic acids, diperoxydodecanedioic acid (DPBDA) and
alkyl monoperoxysuccinic acid. Peracid bleaching species, and
a method for their production, are described in V. S. patent
4,337,213 to Marvnowski et al, the disclosure of which is
incorporated herein by reference. The bleach is present in an
amount sufficient to provide effective bleaching, e.g., from
about 5 to 50% by weight active, preferably from about 8-25%
by weight active, most preferably from about 10 to 13% by
weight active depending on the bleaching species chosen.
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Alkaline Builder
An alkaline builder material is added to provide to a pH of
between about 8-12. The builder also has the capacity to
sequester or precipitate hardness ions (e.s. Ca2+ and
Mg2+). Al~ali-metal carbonates, sesquicarbonates and
bicarbonates are suitable builders, and preferred are sodium
and/or potassium carbonates. The carbonate acts as the
builder to remove diYalent metal ions such as calcium, and
additionally provides alkalinity and aids in soil removal.
Generally, in terms of weight percent of the composition, at
least about 25%, preferably 50%, most preferably 80% carbonate
is employed. Higher levels can be employed, however, at
levels greater than about 90% there is insufficient room for
the other ingredients which contribute to the overall
effectiveness of the composition.
Calcium Stearate Powder
Very low levels of a calcium stearate powder are i~portant to
siqnificantly reduce the levels of CWR in the dry peroxygen
bleaching matrix. Preferred are calcium stearates, available,
for example, from The Synthetic Products Company (Synpro), of
Cleveland, Ohio. Examples of particularly preferred calcium
stearate are Synpro's finely-sized grades, especially grades
15, 12B, 24-46, 114-36, NF and Food Grade. Preferably, the
calcium stearate powder has a particle size distribution such
that at least 95 percent is smaller than a US 200 mesh screen,
and has a bulk density of about O.1-0.4 g/c~3. More
preferably the calclum stearate powder has a particle size
distribution such that at least 99% is smaller than a US 200
mesh screen, and 95% is smaller than a 400 r.esh screen. A
f ine particle size is important to ensure effective coatin~ of
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WO92t21744 PCT/US92/04500
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the other dry ingredients to result in a hydrophobic
S environment, thus mitigating cold water residue.
Granulometer measurements reveal that the most preferred
calcium stearate fine powder has a median grain size of less
than about 25 microns, preferably less than about 10 microns.
Liauid Additives
A surfactant may be provided to prevent "dusting~ of the dry
ingredients, particularly sodium carbonate, sodium perborate,
lS and fluorescent whitening agents. It is most preferred to use
at least one nonionic surfactant, especially Cl_4
alkoxylated aliphatic alcohols and Cl_4 alkoxylated alkyl
phenols. Particularly preferred are ethoxylated/propoxylated
C8_14 alcohols. There should be at least about three alkoxy
groups per alcohol, preferably at least about nine. Examples
of preferred ethoxylated/propoxylated aliphatic alcohols are
BASF Corporation's trademarked INDUSTROL, and PLURAFAC.
Certain Cl_ 4 alkylene oxide copolymers such as ethylene
oxide/propylene oxide copolymers are also preferred as
_S sur a-tant- ~heso are ~xe~-;.Fl ` Cied by ~ASF's tr~demarke~
PLURONIC series. Other suitable nonionic surfactanes are
polyethoxylated alcohols manufactured and marketed by the
Shell Chemical Company under the trademark "NEODOL". Examples
of preferred NEODOLS are NEODOL 25-7 which is a mixture of 12
to 15 carbon chain length alcohols with about 7 ethylene oxide
groups per molecule, NEODOL 2~-65, a C12_13 mixture with
about 6.5 moles of ethylene oxide, and NEODOL 25-9, a C12_15
mixture with about 9 moles of ethylene ~xide. Also useful are
a trimethyl nonyl polyethylene ~lycol ether, manufactured and
marketed by Union Carbide Corporation under the Trade~ark
TERGITOL TMN-6, and an octyl phenoxy polyethoxy ethanol sold
by Rohm and Haas under the Trademark TRITON X-114. Total
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WO92/21744 PCT/US92/04500
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surfactant content may range from 0 to about 5%, preferably
from about 0.1 to 3%, more preferably from 0.2 to 1~ and most
preferably from about 0.2 to 0.3%. It is to be noted that
higher levels of surfactant, and/or its application as an
overly fine spray, tends to cause agglomeration of the calcium
stearate powder, thus severely reducing its effectiveness. It
is also preferred to a ratio of surfactant to calcium stearate
powder be from about 3:1 to 1:5.
Adiuncts
Adjuncts may be added in an amount of from 0 to about 5% and
are useful to improve or enhance efficacy, aesthetics and/or
consumer acceptance of the overall formulation. Enzymes are a
particularly preferred adjunct, and may be selected from
amylases, proteases, cellulases, and lipases. The hydrolytic
enzyme should be present in an amount of about 0.01-2%, more
preferably about 0.5-1%, by weight of the detergent. Mixtures
of any of the foregoing hydrolases are desirable, especially
protease/amylase blends.
Dyes, such as Monastral blue and anthra~uinone dyes (such as
those described in Zielske, U.S. 4,661,293, and
U.S. 4,746,461~, and pigments, e.g. titanium dioxide and
ultramarine blue which are also suitable colorants, can be
selected. Anti-redeposition agents, such as
carboxymethylcellulose, are potentially desirable.
Sequestrants, such as EDTA, citric acid, polyphosphonates,
aminopolyphosphonates, and the like, may also be desirable to
complex transition metal ions which can destabilize bleaches.
Fluorescent whitening agents (FWAs) are desirable
components for inclusion in bleaching formulations, as they
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counteract the yellowing of cotton and synthetic fibers. FWAs
are absorbed ~n fabrics during the washing and/or bleaching
; process. FWAs function by absorbing ultraviolet light, which
is then emitted as visible light, generally in the blue
wavelength ranges. The resultant light emission yields a
brighteninq and whitening effect, which counteracts yellowing
or dulling of the bleached fabric. Such FW~s are available
commercially from sources such as Ciba Geigy Corp. of Basel,
Switzerland, under the trade name "Tinopal". Incorporation
of the FWAs may be afforded by ~ixing a binding agent and
bulking agents e.g., Na2SO4, and colorants. The mixture
is then compacted to form particles, which are admixed into
the bleach product. If added, the FWA particles may comprise
from about 0.1% to 1% by weight of the composition.
A fragrance which imparts a pleasant odor to the bleaching
composition is generally included. As fragrances are subject
to oxidation by bleaches, they may be protected by
encapsulation in polymeric materials such as polyvinyl
alcohol, or by absorbing them into starch or sugar and forming
them into beads. These fragrance beads are soluble in water,
so that fragrance is released when the bleach composition is
dissolved in water, but the fragrance is protected from
oxidation by the bleach during storage.
Buffering, building, and/or bulking agents may also be
present. Boric acid and/or sodium borate are preferred agents
to buffer the pH of the composition. Other buffering agents
and cobuilders such as sodium and potassium silicate, sodium
phosphate, sodium tripolyphosphate, sodium tetraphosphate,
aluminosilicates (zeolites), and organic builders such as
sodium sulfosuccinate may be added. Optionally, fillers such
as sodium sulfate are added. Buffer, builder, and bul~ing
agents are included in the product in particulate form such
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that the entire composition forms a free-flowing dry product.
Buffers and cobuilders and/or bulking agents may range from o
to about 80%, preferably 10-50% by the weight of composition.
For a dry-blend process, liquid ingredients, includinq
liquid adjuncts, are preferably sprayed onto the dry
ingredients after application of the calcium stearate powder,
and more preferably, as a final step. It is important in the
application of liquids, particularly nonaqueous liquids such
as nonionic surfactants, that the application be carried out
in such a way as to prevent aqglomeration of the calcium
stearate. For the preferred method of applying liquids last,
the liquid application apparatus should be selected to deliver
a relatively coarse spray, and mixlng should be gentle to
moderate. A desired coarse spray may be obtained by a pump-fed
non-atomizing nozzle, having a fan-shaped spray pattern. An
example is a nozzle sold under the name T-Jet 11002. It is
within the scope of the dry-blending-process of the present
invention, however, to preload surfactant or other liquids
onto sodium carbonate prior to blending in the remaining dry
ingredients, and prior to adding any remaining liquid
ingredients. I, preloading is undert~ken, the spray density
of surfactant ls less important as long as the carbonate is
sufficiently mixed during and after spraying to assure maximum
absorption of surfactant. It is preferred to employ a
tumble-style or falling curtain rotary mixer for the
preloading, and the surfactant may be applied using an air-fed
atomizing spray apparatus.
Dry adjuncts may be added at any time during the process,
for example with the sodium perborate and carbonate or after
the addition of all liquid ingredients.
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FORMULATION EXAMPLES
s
I nqred i ent y~
Na~C03 60-90
Sodium Perborate 2-30
Calcium Stearate 0.05-0.5
Surfactant 0-5
Enzyme 0-2.0
Brightener 0-0.5
UMB 0-0.2
Fragrance 0-0.3
Ex~erimental
Table I below shows the importance of particle size
distribution of the calcium stearate powder on CWR. The
measurement of CWR is accomplished by placing a measured
quantity of laundry composition, as a single pile, in the
bottom of a washing machine. ~allast (10 lbs. of polycotton
pillow cases) is piled on top of the composition. The washing
machine is set to run a gentle eight minute cycle with 4.5C
incoming wash water. At the end of a complete wash cycle the
ballast is removed and undissolved composition collected and
weighed.
The data of Table I was obtained by placing 110 g of a sodium
perborate/sodium carbonate - based additive formulation,
containing 0.25 weight percent calcium stearate as the calcium
stearate powder, in a pile in a washing machine. Ten pounds
of ballast, in the form of polycotton pillowcases were added,
and the wash was conducted at a water temperature of 4.5C,
with the results shown in the table. All mesh sizes are US
mesh.
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Table I
Hydrophobic Powder
Grade Size Distribution CWR (q)
A60% through 40 83.3
B 80% through 20035.4
C 99% through 200o.o
D 95% through 2000.1
E 99% through 2002.3
F 99% through 2001.7
Control(1) 86.4
(1) No calcium stearate
The results show that grades A and ~ were insufficiently
finely sized to achieve an acceptable reduction in CWR.
Grades C-F, however, yielded an acceptable level of CWR. The
results of Table I are accurate to within 5.0 g, thus C-F
2~ should be considered equal to each other. Generally, less
than about 30 g, preferably less than about 10 g and most
preferably less than about 5 g is acceptable. Alternatively,
CWR is expressed as a percentage by comparing final weight of
laundry product with the initial weight. Expressed as a
percentage of additive remaining after a wash cycle, less than
about 30% more preferably, less than about 10% and most
preferably less than about 5% CWR is acceptable.
Table I~ shows the minimum amount of calcium stearate powder
(as calcium stearate) necessary to achieve acceptable CWR
levels. The calcium stearate was added to a sodium
carbonate/sodium perborate formulation as in the Example, and
had a size distribution of 99% through a 200 mesh screen.
Experimental conditions were as given for Table I above,
except more vigorous agitation was employed in the wash cycle.
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Table II shows that for a sodium carbonate/perborate
composition, at least about 0.05 wt. %, preferably at least
about O.lS wt. S calcium stearate is important to reduce CWR
to acceptable levels.
Table II
Wt. S C lcium Stearate CWR (a~
0.0 78.6
0.025 74.4
0.050 28.6
0.150 0.3
0.250 0.2
0.500 0.1
For perborate/carbonate laundry additive formulations, a level
of calcium stearate powder above 0.5 wt %, the product bridges
or clumps slightly as it is poured with the degree of clumping
becoming worse with increasing calcium stearate powder level.
This phenomenon is seen in the results of Table III whlch
presents angle of repose data for compacted and uncompacted
sodium carbonatejperborate samples containing calcium
stearate, poured in a tilt plate apparatus. The tilt plate is
a twelve inch long smooth surfaced-plate, upon which is placed
about 100 g of sample, in a single pile. The plate is tilted
to various angles and the angle at which the sample begins to
flow is noted.
At a 0.25 weight percent calcium stearate level, the
pourability of the formulation does not change. The 0.5
weight percent level produces a slight change relative to a
stearate-free sample, thus may be considered a maximum level
with respect to product pour/flow characteristics.
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Table III
Anqle of RePose
Wei~ht ~ Calcium Uncom~acted Com~acted
Stearate SamDle Sample
o.oo 20 21
0 25 20 21
0 50 22 22
1.00 24 26
3.00 25 28
5.00 25 28
10.00 26 30O
once dispersed from the bottom of the washer by the agitator
lS the individual granules of additive composition must dissolve
in the bulk solution. Owing to the hydrophobic nature of the
calcium stearate powder, an excess (above about 0.5%) can
interfere with bulk solution dissolution of the additive, as
the additive particles become sufficiently coated to prevent
them from dissolving. Japanese patent application 62-22800
teaches that while stearate alone is effective for reducing
CWR, it also inhibits bulX solution dissolution.
Fiqures 1 and 2 illustrate bulk solution conductivity
profiles for a mixture of sodium carbonate/sodium perborate
and calcium stearat~ at 4.5C. Bulk solution dissolution is
measured by first filling a washing machine with water at the
desired temperature. A 100 g sample was added to the water
in the washer tub, and conductance was measured using a
Radiometer America Conductivity Meter, Model CDM-83.
Conductance is expressed in millisiemens/cm, and increases
with dissolution of the sample.
A11 materials were added to bulk solution (5 lbs ballast, 100
ppm hardness). At the 0.25 weight percent calcium stearate
level, the bulk solution dissolution is equivalent to the
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stearate-free control after eight minutes (both were 84%
dissolved). A reduction in solution conductivity is seen for
the 0.5 wt % stearate level. Based on a conductance vs.
sodium carbonate level calibration curve (not shown) the pure
sodium carbonate is 84% dissolved after eight minutes while
the sodium carbonate with 0.5 wt. % stearate is 79%
dissolved. Therefore, the 0.5 wt. % calcium stearate
prevents approximately S grams (5%) of sodium carbonate from
dissolving after eight minutes. The 0.5% level thus is a
maximal level ~for a sodium perborate/sodium carbonate
additive formulation) above which the beneficial effects of
lS the stearate on addi'ive dissolution is reduced.
Cleanina Performance
To verify that calcium stearate does not reduce perfornance
when a dry bleach composition (containing sodium perborate)
is added directly to solution, standard condition (20, 3~,
and 50C; lOO ppm hardness) performance and multi-cycle
whitening studies were conducted. A leading
commercially-available phosphate detergent served as the
detergent matrix, and a leading commercially-available sodium
perborate/sodium carbonate laundry additive, to which was
added O.0 and 0.5 weight percent calcium stearate, was
tested. The treatments were added directly to solution to
prevent lumping. Soil removal, whitening and redeposition
were each measured colorimetrically by comparing reflectance
measurements on swatches of fabric before and after washing.
Whitening was measured after one, three and five cycles while
redeposition was measured once after five cycles. Soil
removal was measured after one cycle. As seen in the stain
3S and soil averages presented in Table IV, the calcium stearate
does not reduce perfor~ance. All results are shown for the
average of the three wash temperatures. No reduction was
WO92/217~ PCT/~S92/04500
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found on any of the individual performance attributes as well
(such as grass stains on cotton fabric or clay soil on
polycotton fabric).
$able IV
Soi1 Remo~al
Sebum/
3-qtain(l) 2_gOil(2) 3-Fabri~(3)
Additive 75.7 81.9 86.0
Ad~i~ive ~ 0.5 wt. ~ stearate 76.7 83.6 87.7
LSD, 95~ t-test 1.7 3.4 1.4
Whitening Redeoo~ltlon
C~cle 1 Cvcle 3 C~cle 5 Cvcle 5
Additive 17.7 19.5 21.0 -2.9
Additi~e + O.5 wt. ~ ~tearate17.2 18.8 20.8 -3.1
LSD, 95~ t-te~t 0.8 1.1 0.6 1.4
(1) three different proteinaceou~ stain~
t2) two particulate ooils
(3) cotton, poly~otton ant polye~ter
Table V lists the laundry performance improvements achieved
when the additive containing 0.5 wt. % calcium stearate is
placed at the bottom of a washer for a cold water wash.
Because the control formula lumps, it provides less
alkalinity and brighteners to the wash resulting in the
significantly reduced sebum and whitening performance.
Given the CWR results for the 0.15 wt. % and 0.25 wt. %
stearate levels presented in Table II, it is expected that
the Table III results would be achieved by the additive
plus 0.25 wt. % stearate formula as well.
3S
:- , . .: .. ;:. ~~ ,. ,
WO92/21744 PCT/US92/04500
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Table v
Wash Condition Treatment %SR rE~
Sebum/cottonwith stearate72.6
21C, regularwithout stearate67.9
agitationLSD, 95% t-~est 2.5
Sebum/polyester with stearate 95.9
21C, regularwithout stearate91.8
agitationLSD, 95% t-test 3.0
Sebum/3-fabric with stearate 82.8
averagewithout stearate 79.6
21C, regularLSD, 95% t-test1.4
agitation
Whiteningwith stearate 10.7
12.8C, regularwithout stearate 9.1
agitationLSD, 95% t-test l.o
Whiteningwith stearate 8.9
4.5C, regularwithout stearate 6.8
agitationLSD, 95% t-test 0.8
Tables VI and VII illustrates the importance of the method of
the present invention. Mixing time of dry ingredients and
order of addition of surfactant and/or any liquids (e.g.,
fragrance) can impact stearate dispersion, thereby affecting
CWR. The product of Table VI was made as a 10 lb.
dry-blended batch in a tumble mixer.
Table VI
Sample Mixinq Time (Min) CWR(g)
A 5 51.5
A 10 4.8
B 5 52.9
B 10 50.8
B 15 23.0
A = perborate plus 0.25 wt. % calcium stearate
B = A plus 0.40 wt. % nonionic surfactant/fragrance
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Table VI shows that a minimum of ten minutes of mixing (in a
small tumble mixer with gentle-moderate mixing) the dry
ingredients is necessary to attain an acceptable CWR value.
Table VI also illustrates the disadvantages of using a fine
surfactant spray, as this tends to cause agglomeration of the
calcium stearate particles and increase CWX unless mixing is
continued for a long time. The spray apparatus used to
obtain the mixture of Table VI was an atomizing sprayer
embodying a pressure of about 25 psl at 2 g/min delivery.
These spray conditions are accordingly not preferred where
surfactant is added last.
l~ A scale up was run in a 100 lb. batch Pellisrini mixer (a
baffled, tumble mixer) set to provide vigorous mixing. A
surfactant~fragrance mixture was applied as a coarse spray
using a T-Jet 11002 Nozzle at 40 psi and 300 g/min delivery.
A substantial decrease in CWR was evidenced by these process
parameters, as shown in Table VII.
Table VII
Sample Mixinq Time (Min~ CWR(g)
A 5 0.49
A 10 0.45
B 5 3.51
B 10 1.05
~ 15 1.41
A = perborate plus 0.25 wt. % calcium stearate
B = A plus 0.40 wt. % nonionic surfactant/fragrance
Both Tables VI and VII show that dispersion of stearate into
the dry ingredients is important in achieving good CWR. The
five minute value of Sample A of Table VII is sharply
improved owing to the more rapid dispersion of stearate in
the larger, more vigorous Pelligrini mixing apparatus. The
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coarser spray also improved CWR of the B samples, apparently
by sharply reducing the tendency of the fine powder to
agglomerate. Generally, only five minutes of mixing the dry
ingredients, followed by another five minutes after
surfactant addition, is needed to achieve acceptable CWR
values.
While described in terms of the presently preferred
embodiments, it is to be understood that such disclosure is
not to be interpreted as limiting. Various modifications and
alterations will no doubt occur to one skilled in the art
after having read the above disclosure. Accordingly, it is
1~ intended that the appended claims be interpreted as covering
all such modifications and alterations as fall within the
true spirit and scope of the invention.
