Note: Descriptions are shown in the official language in which they were submitted.
2 ~
COMPOSITION AND METHOD FOR FABRIC ENCRUSTATION PREVENTION
This invention relates to compositions and methods
for preventing fabric encrustation by decreasing or
suppressing the formation of encrustation residue when using
detergent applications and formulations during fabric washing
operations with "hard water." In particular, this invention
relates to the use of certain organic dicarboxylic acids to
prevent growth or deposition of insoluble compounds on fabric
surfaces during washing operations. The invention is
primarily concerned with inhibition of the formation and
deposition of insoluble compounds on fabric.
The growth of insoluble compounds on fabric surface
(fabric encrustation) from repeated washing with
non-phosphate detergents in "hard water" is a negative effect
in which the appearance and feel of the fabric are affected.
The fabric acquires a rough feel and colored garments have a
faded appearance.
The insoluble compounds primarily are calcium and
magnesium carbonate precipitates caused by builders, such as
sodium carbonate, typically used in non-phosphate
detergents. Therefore, the prevention of encrustation or the
deposition of insoluble compounds formed during the washing
process with "hard water" is strongly desired. Phosphonates
and polyacrylates have been shown to be effective in
detergent applications for the prevention of encrustation.
Phosphonates can function as crystal growth inhibitors which
3 prevents the growth of insoluble calcium and magnesium
compounds at substoichiometric concentrations. Polyacrylates
can function as sequestering and dispersing agents, as well
as crystal growth inhibitors. Some drawbacks associated with
phosphonates and polyarrylates are that phosphonates can
contribute to euthrophication and polyacrylates are not
biodegradable.
310.104 -1-
20~9 i,
Heavy-duty laundry detergents typically contain two
major ingredients, surfactant and builder, and a number of
other ingredients essential to an acceptable product.
Although of lesser importance to detergency, these additional
ingredients impart certain desirabla functions to the total
formulated detergent. These miscellaneous ingredients
include anti-corrosion agents, anti-soil redeposition agents,
fluorescent whitening agents, bleaches, enzymes, perfume and
the like. The two major components most essential to
deter~ency are surfactant and builder.
The surfactant provides detersive action to the
detergent. This is based on their fundamental characteristic
to absorb or concentrate at the soil/fiber/water interfaces.
The detergent builder functions primarily to prevent divalent
calcium and magnesium water-hardness ions from interfering
with the surfactant action. The builder also may provide
alkalinity thus improve fatty acid saponification and
buffering capacity, prevent flocculation, maintain ionic
strength, extract metals from soils and remove alkaline-earth
metal ions from the washing solutions. Phosphates are
extremely effective builders; however, they are in disfavor
due to their eutrophication effect on lakes and streams.
Many states in the United States have enacted legislation
limiting phosphate content. Such legislation to reduce
phosphate content has led to a variety of non-phosphate
builders, either proposed and/or employed. Examples include
silicates, zeolites, carbonates and polycarboxylates,
citrates, EDTA and sodium nitrilotriacetate (NTA). Such
alternatives are themselves subject to various limitations.
Silicates are not preferred because they are not entirely
water-soluble and they can therefore deposit onto fabrics,
and also can form precipitates with the hardness ions.
Zeolites are generally effective co-builders, but not
necessarily as the sole builder. Polycarboxylate builders
are costly.
310.104 -2-
`
:
, 2 ~
High levels of alkali-metal carbonates have been
found to be an effective non-phosphate builder, particularly
in applications where a high pH is required, e.g., for oily
soil removal. A drawback associated with such high carbonate
levels is that calcium and magnesium ions present in the
washing water readily form precipitates with the
carbonates,and such precipitates deposit and/or form on the
fabrics. These precipitates leave the fabrics with a rough
feel and faded appearance. Various approaches have been
employed in the art to combat the formation of calcium or
magnesium precipitates, including the addition of seed
crystals, crystal growth inhibitors and non-precipitating
sequestrants. Non-precipitating sequestering and complexing
agents tend to be expensive due to the stoichiometric levels
needed, adding significantly to the overall formula cost.
' 15
Discussion of Prior Art
U.S. Pat. 3,896,056, Benjamin et al., relates to a
built detergent compositions which contain as essential
ingredients, an organic surface-active agent; a precipitating
builder; and a precipitation modifier. This patent describes
a functional test to assess the ability of compounds to
prevent the formation of precipitation as an indication of
its effectiveness as a crystal growth inhibitor. A detergent
matrix consisting of an inorganic precipitating builder is
used. A number of polycarboxylic acid compounds are
disclosed as precipitation modifiers.
U.S. Pat. 4,097,016, 8rahm, J., et al., relates to a
solid composition for washing, cleaning and bleaching,
including at least one basic compound, as a solid polylactone
is a sequestering agent and can include activators for
per-salts, such as anhydrides of organic acids, succinic
acid, phthalic acid, and the li~e.
310.104 -3-
2 ~ v `~ 7
U.S. Pat. 4,814,102, Baur, R. et al., describes
copolymers consisting of acrylic, maleic, furmaric, itaconic
or hydroxy alkyl esters of these acids as builders,
encrustation inhibitors, or dispersents in detergents.
Non-phosphate detergent formulations are disclosed
in numerous patents. Larrabee et al., EP 130,640, discloses
a laundry detergent comprising a surfactant, 5 to 80% of a
non-phosphorus detergent builder which may be a carbonate,
and about 0.3 to 5% of a polyacrylate polymer. EP 137,669,
ln Kermode et al., describes a detergent composition including 5
to 60~ of a surfactant, 7 to 80% of a polycarboxylate/zeolite
builder, and a bleach system.
~eRider et al., EP 82 564, discloses machine
dishwashing and rinsing compositions having nonionic
detergent surfactants, a water-soluble calcium sequestering
agent, specific polymeric material and an alkaline detergent
material to produce a composition which has improved
non-filming, non-spotting or non-streaking properties. The
calcium sequestering agents are taught to be an organic
builder salt, such as water-soluble citrates, water-soluble
salt of nitrilotriacetic acid (NTA), water-soluble salt of
carboxymethoxy succinic acid, or other builders such as
zeolites, or organic chelating agents.
EP 82 564 shows an example of the calcium
sequestering agent; dipicolinic acid is disclosed as not
causing filming on dishes. Similarly, in U.S. 3,850,852,
Neillie et al., sodium carbonate is combined with
polyacrylate, phosphonate, and a calcium sequestering agent.
EP 233 730, Sanderson et al. discloses the use of
2,6-pyridine dicarboxylic acid as a chelating stabilizer for
potassium sulfoperoxybenzoate in detergent compositions.
This is necessary in the situation where inorganic or organic
peroxy acids are unstable in the presence of nonionic
310.104 -4-
2 ~
surfactants. It was not feasible to contemplate storing
liquid compositions containing both components without the
use of a chelating peroxidic stabilizer such as dipicolinic
acid.
EP 266 904, Frankena, H., relates to machine
dishwashing compositions comprising low or zero phosphates
using dipicolinic acid derivatives as the builder. Also
provided for are enzymes to increase performance.
The prior art describes polymers of aliphatic
polycarboxylic acids as builders in detergent formulations.
However, it has not been recognized that substoichiometric
concentrations of the monomeric forms of some of these
compounds alter the kinetics or crystalline morphology of
calcium carbonate, and hence can be used to prevent
industrial scaling, and reduced fabric encrustation in
non-phosphorus detergent formulations. In view of the art
cited, there remains a need for compositions and methods for
effectively preventing fabric encrustation in detergent
applications and formulations. Compounds of the present
invention are primarily effective at preventing encrustation
of fabrics in high-carbonate, non-phosphorus detergent.
Therefore, the present invention provides an alternative to
phosphonate and polyacrylates for prevention of encrustation.
The present application relates to the compositions
and method for using certain organic dicarboxylic acids and
water-soluble derivatives thereof as effective fabric
encrustation preventatives in detergent applications and
formulations. The prior art relates only to the use of
certain organic dicarboxylic acids to reduce hardness of
water, or as a stabilizer against degradation of peroxy
bleaching compounds. Clearly, the addition of certain
organic dicarboxylic acid and their water-soluble salts and
anhydrides into detergent compositions in order to decrease
and/or suppress the formation of encrustation residue in
310.104 -5-
fabrics from hard water minerals due to the ~e~e~ f the
sodium carbonate builder in the detergent formulation is not
contemplated by the prior art.
A leading inorganic replacement for phosphate
builders is sodium carbonate. However, high carbonate
content non-phosphate builders produce the problem of "hard
water" precipitates from the calcium and magnesium ions
present in the "hard water." The growth or deposition of th~
precipitates on the fabrics during washing application make
carbonate-based detergents, otherwise, not preferred.
It is therefore an object of the present invention
to provide a cleaning composition which does not utilize
phosphate builders.
It is another object of the present invention to
provide a high carbonate cleaning composition which results
in reduced levels of calcium and magnesium salt deposition on
fabrics.
It is another object of the present invention to
provide a biodegradable, entirely non-phosphorus-containing
compound which prevents carbonate salt precipitation and/or
controls encrustation.
It is another object of the present invention to
provide a cleaning composition which provides stain and soil
removal performance.
It is another ob~ect of the present invention to
provide a cleaning composition and method for the reduction
of fabric encrustation which does not contribute to
euthrophication and is biodegradable.
` 35
3 10 n 104 6
2 ~
of fabric encrustation when using high carbonate or
non-phosphate detergent formulations.
Summary of the Invention
It has now been found that by using the compositions
and method in accordance with the present invention, fabric
encrustation can be reduced or eliminated when using high
carbonate, non-phosphate detergents with water containing
calcium and/or magnesium ions. The compositions and method
are characterized by utilizing certain water-soluble organic
dicarboxylic acids, anhydrides, salts and derivatives
thereof. More preferably, this invention relates to the use
of certain organic dicarboxylic acids, water-soluble salts
and anhydrides thereof, especially ketomalonic acid,
hydroxymalonic acid and 2,6-pyridine dicarboxylic acid in the
detergent compositions and methods utilizing said
compositions.
More particularly, this invention relates to the use
of detergent compositions which contain ketomalonic acid and
2,6-pyridine dicarboxylic acid or a water-soluble salt
thereof with monovalent cations in a concentration of from
about 1 to about 20 percent by weight, preferably from about
2 to about 12 percent by weight.
Alkali metal salts, particularly sodium salts,
potassium salts or ammonium salts, can be used as
water-soluble salts of the organic dicarboxylic acids of the
instant invention having monovalent cations. Ammonium ions
also can be regarded as monovalent cations for the purpose of
the present invention. It is noted that for the purpose of
the present invention the acid or anhydride forms of the
organic dicarboxylic acids are equivalent to the salt forms
except where the acid has limited solubility. It is
understood that the anhydride can hydrolyze to form the
diacid in situ. It is also noted that except where
310.104 -7-
2 o ~
explicitly stated or implied from the context, the acid and
salt forms are used interchangeably. It is further noted
that if the organic dicarboxylic acid derivative is added as
a water-soluble salt, the required weight percentage range
will be higher than that of the acid, due to the presence of
the counter ion.
Therefore, in one embodiment, the present invention
can be described as a cleaning detergent composition
comprising (a) an alkali-metal carbonate builder; and (b) a
fabric encrustation prohibiting amount of an organic
dicarboxylic acid,anhydride or salt thereof.
Alkali-metal carbonate. The alkali metal carbonate
is the primary and may be the only builder material of the
composition of the present invention. As used herein, the
primary builder is defined as that builder which, in total
amount, has the higher capacity for hardness ions (e.g.,
calcium (+2) and magnesium (+2)). The term "co-builder" will
refer to any remaining builder which has the lesser capacity
(typically less than 30%) for such ions. Alkali metal
carbonates, sesquicarbonates and bicarbonates are suitable
primary builders; however, the preferred builders are sodium
and/or potassium carbonates. A building effective amount of
carbonate is present in the compositions herein, which is
defined as that amount of alkali metal carbonates, as the
primary builder, which would precipitate in the presence of
hardness ions, in solution, during a wash period at 50C and
250 ppm hardness. Such precipitation is determined by an
increase in solution turbidity as indicated by an abrupt
change in percent transmittance versus time (defined
additionally hereinafter). Generally, in terms of weight
percent, and assuming 68 liters of wash water and about 100 g
of composition, at least about 30 percent, preferably 40
percent, most preferably 50 percent carbonate is employed.
As used herein, unless otherwise stated, all percentages are
weight percentages of actives of the total composition.
310.104 -8-
~ ~ ~3 ~
Higher levels of carbonate will function, however, at levels
greater than about 80 percent there is insufficient room for
the other ingredients which contribute to the overall
effectiveness of the composition. The carbonate acts as the
builder to remove divalent metal ions such as calcium, and
additionally provides alkalinity and aids in soil removal.
At the high levels disclosed herein, the alkali metal
carbonate provides good cleaning performance and in
situations requiring a high pH, such as oily soils, the
carbonate builder may be superior to other builders.
oraanic Dicarboxylic Acid Encrustation Preventative Svstem
The preventative system comprises substoichiometric
levels of an organic dicarboxylic acid, water-soluble salt or
anhydrides thereof, which act to inhibit fabric
encrustation. For purposes herein, substoichiometric levels
of the certain organic dicarboxylic acid are defined to mean
levels which are not able to prevent the precipitation of
calcium and magnesium carbonate by sequestering water
hardness ions. For example, such levels generally comprise
less than about 30 percent, more preferably less than about
20 percent, of the total building capacity.
By the term "organic dicarboxylic acid" it is meant
an organic compound having at least 2 carboxyl groups. The
certain and particular organic dicarboxylic acid compounds of
this invention relate to the following general formulae
1l ~ ~ c~
M20C- R- COM1 and R 0
wherein
R is selected from the group consisting of
2,3-pyridenyl, 2,4-pyridenyl, 2,6-pyridenyl, 1,2-phenylene,
1,3-phenylene and
310.104 -9-
20~4~7
rR~
_ ~C~--(CH2)n
R' m
wherein R' and R" are independently H, -OH or lower alkyl
having 1-4 carbon atoms, inclusive or R' and R" taken
together are oxygen;
n is an integer from from 0 to 3, inclusive;
m is an integer from 0 to 2 when R' is -OH; and
M1 and M2 are independently selected from the
group consisting of sodium, potassium, lithium and ammonium.
The following are representative compounds of this
invention:
O
~ -OH
Compound 1 ~ I_OH
Phthalic acid
0
C-OH
Compound 2 ~
O=C-OH
Isophthalic acid
o
C-OH
. 30
Compound 3 ~
~N ~ C-OH
2,4-Pyridine dicarboxylic acid
310.104 -10-
2 ~
<~ ~ -OH
Compound 4 O ~N
Hll -C /
2,6-Pyridine dicarboxylic acid
1~
~ ~ C-OH
Compound 5 I j~
o
2,3-Pyridine dicarboxylic acid
O
Compound 6 HOCCOH
o
Oxalic acid
;"
i
Compound 7 HOC-CH2C-OH
Malonic acid
:
O O
Compound 8 HOC-CH-C-OH
OH
Hydroxy malonic acid
O OH O
Compound 9 HOC-C - COH
Ketomalonic acid
O O
Compound 10 HOC-CH-C-OH
CH~
Methyl malonic acid
310.104 -11-
2 ~ J' `_~ ~
O O
Il li
Compound 11 HOC-CH2-CH2-C-OH
Succinic acid
O O
Compound 12 Hoc(cH2)4coH
Adipic acid
O O
Compound 13HOC-CH-CH2-C-OH
OH
Hydroxy succinic acid
O IH
Compound 14HOC-CH-CH-C-OH
OH o
Tartaric acid
:
In a second embodiment, the cleaning composition
comprises a detergent composition including:
(a) an alkali-metal carbonate builder;
(b) in encrustation prevention system comprising
substoichiometric levels of organic
dicarboxylic acid, water-soluble salts and
~; anhydrides thereof; and
(c) a surfactant.
Components (a) and (b) are as described previously
with respect to the first embodiment. Component (c) i5
further described below.
Surfactant
A myriad of surfactants are known to be suitable for
laundry applications, including anionic, cationic, nonionic
and amphoteric surfactants. Preferred surfactants are
anionic, nonionic and mixtures thereof, and if added are
present in a cleaning-effective amount. Preferred anionics
310.104 -12-
2 ~
are selected from surfactants such as alkali metal alkyl
sulfates, primary and secondary alkane sulfonates, linear
alkyl benzene sulfonates, alkyl ether sulfates, and mixtures
thereof. These anionic surfactants will preferably have
alkyl chain groups averaging about 8 to 18 carbon atoms. The
preferred anionic surfactant is a LAS having an alkyl group
averaging 8 to 18 carbons. Co ercial sources of such
surfactants are the Stephan Chemical Company (Northfield, IL)
and the Vista Chemical Company (Houston, TX). An
additionally preferred anionic surfactant, principally for
its cleaning effectiveness, is a secondary alkane sulfonate.
An example of a particularly preferred secondary alkane
sulfonate is HOSTAPUR SAS, a trademarked product manufactured
by Farbwerke Hoechst A.G. (Frankfurt, West Germany).
.,
It is most preferred to include with the anionic
surfactant at least one nonionic, especially C1_4
alkoxylated aliphatic alcohols and C1_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 (Parsippany, NJ) trademarked
INDUSTROL, and PLURAFAC. Certain Cl_4 alkylene oxide
copolymers such as ethylene oxide/propylene oxide copolymers
are also preferred as surfactants. These are exemplified by
BASF I 5 trademarked PLURONIC series. Other suitable nonionic
surfactants are polyethoxylated alcohols manufactured and
marketed by the Shell Chemical Company (Houston, TX) ~nder
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 23-65, 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 oxide. Also useful are a
trimethyl nonyl polyethylene glycol ether, manufactured and
marketed by Union Carbide Corporation under the trademark
310.104 -13-
204~
- TER~ITOL TMN-6, and an octyl phenoxy polyethoxy ethanol sold
by Rohm and Haas (Philadelphia, PA) under the trademark
TRITON X-114. Total surfactant content is preferably from
0.1% to about 20%, more preferably from about 2% to 15%.
; 5 In a third embodiment, the present inventioncomprises a dry, granular laundry detergent composition
comprising:
(a) an alkali-metal carbonate builder;
(b) certain organic dicarboxylic acid or a water-
soluble salt thereof as encrustation inhibitor system;
(c) a surfactant;
; (d) a bleach;
(e) an alkali-metal silicate;
(f) a filler; and
~g) laundry adjuncts.
Elements (a), (b) and (c) are as described in the first and
second embodiments. Elements (d) through (g) are further
described hereinbelow.
~,v
Bleach
Preferred peroxygen bleaches are available in solid
form and include sodium percarbonate, sodium perborate,
sodium phosphate peroxyhydrate, potassium permonosulfates and
metal peroxides. Bleach activators, also known as peracid
precursors, can be included with the peroxygen compounds.
Examples of activators include tetraacetyl ethylenediamine
(TAED), nonanoyloxy benzene-sulfonate (NOBS), and nonanoyl-
glycolate phenol sulfonate (NOGPS). NOBS and TAED are
disclosed, for example, in U.S. 4,417,934, Chung et al., and
NOGPS is disclosed, for example, in U.S. 4,778,618, Fong et
al., the disclosures of which are incorporated herein by
reference. Peracid bleaches (including monoperacids and
diperacids) may be advantageous in terms of bleaching
performance. Suitable peracid bleaching species include
C8_12 al~yl peracids, especially perazelaic and
diperazelaic acids, diperoxydodecanedioic acid (DPDDA), and
310.104 -14-
2 ~ Q ~ 7
alkyl monoperoxysuccinic acid. Peracid bleaching species,
and a method for their production, are described in U.S.
4,337,213 to Marynowski 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 0% to 10% by weight active, more preferably from
about 0.05% to 5% by weight active depending on the bleaching
species chosen.
Also suitable are chlorine bleaches which could be
preformed and suspended on a substrate, mitigated or
generated in situ.
Alkali-metal Silicate
An alkali-metal silicate can be included to provide
alkalinity and corrosion resistance. Preferred is one having
the formula:
M20(siO2)n
where M represents an alkali-metal and n is between about 1
and 4. Preferred alkali-metal silicztes are sodium,
potassium and lithium silicates, with sodium silicate being
the most preferred, and with a preferred n value of 2.0-2.4.
A most preferred maximum value for n is about 3.2 in order to
minimize insoluble silicates during storage. It is further
preferred that at least about 10% of the total silicates have
an n value of greater than about 1.6 to impart suitable anti-
corrosive properties. Examples of other suitable silicates
include sodium or potassium orthosilicates and
metasilicates. As used hereinafter, the term "silicate" will
be taken to mean any of these alkali-metal silicates,
individually or combined.
Mixtures of any of the foregoing alkali-metal
silicates are also suitable. The alkali-metal silicate is
present in an amount of from about 0% to 10%, preferably
about 2~ to 5%. A minimum of about 1% silicate is preferred
to provide adequate corrosion resistance. A commercially
310.104 -15-
2 ~
available sodium silicate is sold by the Philadelphia Quartz
Corporation (Valley Forge, PA) under the trademarks RU (as a
47% solution) and D (as a 44.1% solution~. In addition to
their anti-corrosive effects, the silicates provide
alkalinity and serve as processing aids to increase particle
size of the agglomerates. Sodium silicates also aid in
cleaning, especially on oil and gréase stains.
Filler
The filler i8 preferably a salt such as sodium
chloride, nitrate or sulfate, and is used to adjust the
composition density to achieve desired physical
characteristics, e.g., grain size and flowability. Depending
on the filler and the process used, the filler can also
provide surface area for loading of actives. The filler
material additionally assists in solubility under cold water
washing conditions. Sodium chloride is preferred due to its
low cost and availability. However, other materials, such as
puffed borax, bentonite clays and inorganic salts such as
sodium or potassium sulfate, chloride, bromide, nitrate, and
borate, and organic materials like sugars may also be
suitable. Some water may be deliberately added as a filler.
Generally, about 0-30% filler will be present, preferably
about 5-25%.
Co-Builder
optionally, any non-phosphate builder material known
in the art to be compatible with the high carbonate
formulation herein may be included as a co-builder selected
from the group consisting of silicates, citrates, polymeric
polycarboxylic acids such as polyacrylates and malonic
anhydride based co-polymers, zeolites, salts of ethylene
diaminetetraacetic acid and sodium nitrilotriacetate.
Silicates at levels above about 10%, and citrates may be
added as co-builders. If added, the co-builder should
comprise no more than about 30% of the total weight of the
composition, and preferably no more than about 20%. Zeolites
310.104 -16-
2 ~
are preferred as optional co-builders since they perform well
when used in a non-encrustation promoting amount. A
; non-encrustation promoting amount is that amount which will
not contribute to or encourage the encrustation formation
when present in a detergent formulation and in the presence
of water hardness ions.
Zeolite A is available, for example, from the PQ
Corp., Valley Forge, PA, under the trademark VALFOR 100.
Zeolite A typically includes about 21% moisture.
Adiuncts
While the alkali-metal carbonate is generally
sufficient to keep the wash p~ range within the desired
limits, it may be desirable to adjust the pH of the wash
water by including an electrolyte/buffer. Generally, these
are alkali-metal inorganic acid salts, hydroxides or oxides.
It may also be suitable to use such materials as aluminates
and organic materials, such as gluconates, citrates,
succinates, maleates, and their alkali metal salts. The wash
pH range should be maintained between about 8.0 to 13.0, more
preferably about 9.0 to 12Ø If an electrolyte/buffer is
needed, sodium hydroxide is preferred, as it does not
interact adversely with any other ingredients and is very
cost effective. The amount of electrolyte/buffer added
2S solely for purposes of buffering can vary from about 0% to
10%.
In the standard composition, minor additions can be
included in the present invention. These include dyes, such
as Monastral blue and anthraquinone dyes (such as those
described in Zielske, U.S. 4,661,293 and U.S. 4,746,461).
Pigments, which are also suitable colorants, can be selected,
without limitation, from titanium dioxide, ultramarine blue
(see also, Chang et al., U.S. 4,708,816), and colored
aluminosilicates. Fluorescent whitening agents are other
desirable adjuncts. These include the stilbene,styrene and
310.104 -17-
2~9~7
styrene, and naphthalene derivatives, which upon being
impinged by ultraviolet light, emit or fluorescent light in a
visible wavelength. These fluorescent whitener agents or
brighteners are useful for improving the appearance of
fabrics which have become dingy through repeated soilings and
washings. Preferred fluorescent whitener agents are TINOPAL
5BM-GX and TINOPAL AMS, both from Ciba Geigy A.G., (Tom
River, NJ) and PHORWITE RKH, from Mobay Chemicals (Union,
NJ).
Enzymes, particularly hydrolases such as lipases,
proteases and amylases, are useful additives in the
compositions herein. Suitable commercial sources include
ESPERASE and SAVINASE, both trademarked products of Novo
Industries (Danbury, CT). Generally, very low levels of
enzymes are needed, i.e. from about 0.1% to 1.0% by weight.
Fragrances are also desirable adjuncts in these
compositions. The total composition minors will range from
0% to about 5%. Anti-redeposition agents, such as
carboxymethyl-cellulose, are potentially desirable. Foam
boosters, such as appropriate anionic surfactants, may be
appropriate for inclusion herein. Also, in the case of
excess foaming resulting from the use of certain surfactants,
anti-foaming agents, such as alkylated polysiloxanes, e.g.,
dimethylpolysiloxane, would be desirable. Water may be
present as free water or as water of hydration of the
inorganic salts such as sodium carbonate. The detergent
composition is prepared by a process which yields a dry,
free-flowing granular mixture, for example agglomeration or
spray drying. However, the compositions herein are not
limited to such forms, and may also be formulated in other
dry forms, such as tablets or beads, or may be formulated as
pastes, gels or liquids. An example formulation i5 shown
below as Example A.
:
310.104 -18-
2 ~ L~ , di 7
EXAMPLE A
Ingredient Wt.% Active
Alkali metal carbonate 30-80
Surfactant 1-20
Bleaching agent 0-10
Alkali metal silicate 0-10
(SiO2/M20)
Filler 0-30
organic dicarboxylic acid, salt or anhydride 0.1-15
Composition Minors (enzymes, FWA's,
fragrances, etc.) 0-5
Co-builder 0-30
Water 0-15
EXPERIMENTAL
To assess effectiveness of the compositions herein
in reducing encrustation deposition, compounds of this
invention were tested for their effectiveness at reducing
encrustation in beaker studies. The compounds and results
are given in the following table.
Procedure
The turbidity measurement comprises measuring
percent transmittance using a dipping probe and colorimeter.
The probe is placed in deionized water and the percent
transmittance (%T.) is set to 100%. The detergent is
predissolved in 50 ml of water, then added to 950 ml of water
containing hardness ions as [Ca2+]/[Mg2+] = 3/1 molar
ratio. The final solution hardness was 300 ppm. Percent
transmittance is continuously plotted and measured vs time.
Results are presented as time before the onset of calcium
precipitation (tm) as determined by an abrupt change in the
slope of a graph of %T vs time. The longer the tm~ the
more effective the crystal growth inhibitor. Ideally, with
the crystal growth inhibitor type compounds, the tm should
be longer than the wash cycle, i.e., about 12-15 minutes in
the case of washing conditions in the United States. In
practice, a tm of greater than about 10, preferably 12
minute~s, provides commercially-acceptable results, as calcium
precipitation will still be inhibited to a degree sufficient
to avoid consumer preception thereof.
310.104 -19-
2 ~ ~ ~ v ~ ~
Simultaneously with the %T measurement, each
container of detergent sample has immersed therein a 3.5 x 4
inch 100% cotton swatch, trimmed to 1.0 grams. Slits
approximately 3 inches long were made about 0.25 inch apart
for better circulation in the test container. After washing
for 10 minutes, the swatch is rinsed twice with 2 L deionized
water, and placed in a flas~ containing 25 ml of water and 10
ml of 1.2M HCl to dissolve the caco3. Fifteen ml of a
standard NH40H hardness buffer and a Calmagite indicator
are then added and the solution is titrated with standardized
EDTA. Results are reported as mg CaCO3 per gram of fabric
(swatch). Preferably, this value should be below about 4
mg/g, most preferably below about 2 mg/g.
The preferred level of calcium carbonate deposits
per gram of fabric can be achieved without necessarily
extending the tm value. Although it is understood that
this invention is not bound by theory, it is believed that
precipitation modifiers will have little or no effect or may
actually shorten the tm value and still provide low levels
of fabric encrustation. Crystal growth inhibitors, on the
other hand, will extend the tm value. The presence of
either of these compound types in a high carbonate
non-phosphate built detergent has been found to result in
lower levels of encrustation on the fabric surface.
310.104 -20-
~A~
TABLE I
Time Before Titration of
Precipitation in Calcium Deposits
CmDd. No. Solution t~ (mins) (mq as CaCo3!am
Beaker Studiesa
Base only 4.5 12.90
1 5.0 6.68
2 9.5 1.80
3 3.2 9.80
4 <1.0 1.10
2.5 10.20
6b 7.5 6.38
7b 10.5 4.30
8 15.8 0.90
9 <1.0 1.30
2.0 2.69
b 11.4 3.50
12b 7.8 5.90
13 4.9 6.88
14 6.1 5.20
(a) An agglomerated no-P detergent base was used which
contained 1.16 gm/l of Na2C03. All acids were
evaluated at 1.0 x 10-3M unless otherwise specified.
(b) Compounds evaluated at 1.27 x 10-3M.
Multicycle Wash Study
To assess effectiveness of the compositions herein in
reducing encrustation deposition, 100% terry cloth washcloths
were washed for multiple cycles, under the given wash
conditions. A base detergent composition consisting of 61%
Na2C03, 11.0% surfactant, 5.0% sodium silicate and 5.0%
sodium perborate were used. The organic dicarboxylic acid
compound was added to the base composition in the amounts
indicated in each case as exemplified in Table II. About 3/4
cup (125 gm/use) of detergent and about 68 l of wash water
was used for each washload.
310.104 -21-
2 ~
TABLE II
Multicycle Wash Studies
B. Multicvcle Wash Studies
Wt. % Ash/5 Cycles/Cotton Washclothsb
Treatmenta 35C/lOO ppm 50C/200 ~pm
Base + 7.5 g Acyrsol LMW 45N 0.4 4.7
(4500 MW polyacrylic acid)
Base + 5xlO 4M 2,6-pyridine 1.5 1.2
dicarboxylic acid (5.68 gm)
Base + 2.5 x 10 4M ketomalonic 0.7 0.9
acid (2.31 gm)
Base + 5 x 10 4M ketomalonic 0.2 0.5
acid (4.62 gm)
(a) Multicycle wash studies were done with an
agglomerated detergent containing 61 gm/use
lS Na2CO3. All studies were done with 3/l Ca/Mg
molar concentration water hardness. Concentrations
are on an "actives" basis.
(b) Ash is defined as the residue remaining after
pyrolysis at 950C in oxygen. Values are expressed
as weight percent.
Table II show~ that substoichiometric levels of the
present encrustation preventative system utilizing an organic
dicarboxylic acid of this invention yielded less calcium
'~ residue (as ash) than the base detergent composition at two
different treatment levels. With the observed results for
2S the inhibition of calcium carbonate deposition, an organic
dicarboxylic acid according to this invention could be a
direct replacement for polyacrylate which is known for its
anti-precipitation nature. Furthermore, the organic
3 dicarboxylic acid and water-soluble salts and anhydrides
thereof should be more biodegradable than polyacrylates.
While this invention has been described and
illustrated with specific examples and descriptions, it is
understood that the invention is not to be limited to the
exact details of operation or exact components shown and
310.104 -22-
2~9~7
described herein, as obvious modifications and equivalents
will be apparent to those skilled in the art to which this
invention pertains. Therefore, the invention is to be
limited only by the scope within the claims appended hereto.
3S
310.104 -23-
