Note: Descriptions are shown in the official language in which they were submitted.
~LZ~74 ~
62301-1385
This invention relates to stable, built, enzyme~
containing liquid detergent compositions suitable for laundry
or pre-soak formulations. More particularly, the invention
relates to aqueous enzyme-containing liquid detergen-t composi-
tions which contain one or more detergent builders and which
are characterized by being physically stable, homogeneous
liquid compositions.
The formulation Gf stabilized enzyme-containing
liquid detergent compositions has been the focus of much atten-
tion in the prior ar-t. The desirability of incorporating
enzymes into detergent compositions i9 primarily clue to the
e~fectiveness of proteolytic and am~lolytic enzyme~ ln ~ecom-
posing proteinaceous and starchy materials found on soiled
fabrics, thereby facilitating the removal o~ s-tains, such as,
gravy stains, blood stains, chocolate stains and the like dur-
ing laundering. However, enzymatic materials suitable for
laundry compositions, particularly proteolytic enzymes, are
relatively expensive. Indeed, they generally are among the
most expensive ingredients in a typical commercial liquid
detergent composition, even though they are present in rela-
tively minor amounts. Moreover, enzymes are known to be un-
stable in aqueous compositions. It is for this reason that an
excess of enzymes is generally required in liquid detergent
; formulations to compensate for the expected loss of enzyme
activity during prolonged periods of storage. Accordingly, the
prior art is replete with suggestions for stabilizing enzyme-
containing liquid detergent compositions, and in particular
unbuilt liquid compositions by the use o~ various materials
which are incorporated into the composition to function as
enzyme stabilizers.
2 -
~ ~'
~Z~74-~
62301-1385
In the case of liquid detergent compositions contain-
ing a builder, the problem of enzyme instability is particular-
ly acute. Primarily this is because detergent builders have a
destabilizing effect on enzymes, even in compositions contain-
ing enzyme stabilizers which are otherwise effective in unbuilt
formulations. Moreover, the incorporation of a builder into a
liquid detergent composition poses an additional problem, name-
ly, the ability to form a stable single-phase composition; the
solubility of sodium tripolyphosphate, for example, being rela-
tively limited in aqueous compositions, and especially in thepresence of anionic and nonionic detergents.
In U.K. Patent l~pplication G.B. 2,079,305, published
January 20, 1982, there i~ disclosed an aqueous built enzyme-
containing liquid detergent composition which is stabilized by
a mixture of a polyol and boric acid. As noted in the examples
of the U.K. application, relatively large amounts of glycerol
are required to stabilize t~e enzymes in the composition. Yet,
as demonstrated hereinafter in the present specification, the
enzyme stabilizing effect pro~ided by a mixture of glycerine
and borax in a buil-t aqueous liquid detergent composition is
relatively modest.
-- 3
~7~
In European Patent Application Publication No. 0126505,
there is disclosed an aqueous enzyme-containing liquid detergent
composition containing an enzyme stabilizing mixture consisting
of certain dicarboxylic acids and borax. The dicarboxylic acids
are recommended as a substitute for a polyol such as glycerol
in known enzyme stabilizing mixtures consisting of glycerol and
a boron compound. However, the dicarboxylic acid-borax mixtures
of this publication in common with the aforementioned prior art
mixture of glycerine and borax are incapable of providing anything
other than a modest stabilizing effect in the present built liquid
detergent compositions. ~1ence there is a need to markedly improve
enzyme stability in aqueous built liquid detergent compositions oE
the type herein defined to levels far beyond the present capabili~y
of the art.
-3a-
~2~74 ~
62301-1385
SUMMARY OF THE INVENTION
The present invention provides a stabilized built,
enzyme-containing liquid detergent composition comprising:
(a) from about 5 to 2Q%, by weight, of one or more sur-
face active detergent compounds selected from the
group consisting of anionic, nonionic and amphoteric
detergent compounds;
(b) Erom about 5 to 30~, by weight, of one or more build-
er salts selected from the group consisting of alkali
metal tripolyphosphates, alkali metal carbonates,
alkali metal nitrilotriacetates, and polyaceta~. car-
boxylates;
(c) an eEfective amount o an enzyme or an enzyme mixture
selected from the group consisting of alkaline pro-
tease enzymes and alpha-amylase enzymes;
(d) an enzyme-stabilizing system containing, based on the
weight of the detergent composition, (i) from about 1
to 10% glycerine; (ii) from about 1 to 8% of a boron
compound selected from the group consisting of boric
acid, boric oxide and alkali metal borates and; (iii)
from about 0.5 to 8% of a carboxylic acid compound
selected from the group consisting of mono, di and/or
polycarboxylic acids having 2 to 8 carbon atoms other
than acetic and propionic acids and water-soluble
salts thereof; and
(e) the balance comprising water and optionally perfume
and other adjuvants.
-- 4
., ,~
~Z974~:1
62301-1385
In a preferred embodiment of the invention, the
li~uid detergent composition comprises:
(a) from about 5 to 15% of an alkali metal alkylbenzene
sulfonate wherein the alkyl group contains 12 to 15
carbon atoms;
(b) from about 2 to 5% of an alkali metal alkyl poly-
ethoxy sulfate wherein the alkyl group contains 10 to
18 carbon atoms and the polyethoxy is of 3 to 11
ethylene oxide groups, the weight ratio of (a) to (b)
being from about 2:1 to about 8:1;
tc) from about 5 to 30% of sodium tripolyphosphate;
(d) from about 1 to 10~ of sodium carbonate, the weight
ratio of (c) to (d) being from about 2:1 to about
6:1;
(e) an effective amount of the aforesaid enzyme or enzyme
mixture;
(f) an enzyme stabilizing system containing, based on the
weight of -the detergent composition, (i) from about 3
to 7% glycerine (ii) from about 1 to 5% oE an alkali ..
metal borate and (iii) from about 0.5 to 4% of said
carboxylic acid compound, and
(g) the balance comprising water and optionally perfume
and other adjuvants.
In accordance with the process of the invention,
laundering of stained and/or soiled materials is affected by
contacting such materials with an aqueous solution of the
above-defined liquid detergent compositions.
-- 5 -
~L2~4 ~J.
62301-1385
The described liquid detergent is a commercially
acceptable heavy duty laundry detergent, capable of satis-
factorily cleaning laundry items containing both oily and par-
ticulate soils. Additionally, the described compositions may
be employed for the pre-treatment of badly soiled areas, such
as collars and cuffs, of items to be laundered.
The present invention is predicated upon the discov-
ery of a three component enzyme stabilizing system as herein
defined which provides an enzyme stabilizing effect to the
liquid detergent compositions of the invention far in excess of
that which can be achieved with conventional enzyme stabili-
zers. The enzyme stabilizing effect thus achieved reflects a
synergy among the three components. In accordance with the
invention, the enzyme stability provided by a mixture oE
glycerine and borax or a mixture of borax and a dicarboxylic
acid as disclosed in the prior art can be synergistically
improved by the use of the three component stabilizing system
herein defined in the present liquid compositions so as to
raise the level of enzyme stability significantly above that
provided by either the mixture of glycerine and borax or the
mixture of borax and dicarboxylic acid when used independently
of each other as enzyme stabilizers. For commercial purposes,
a desirable enzyme stability generally corresponds to about a
half-life of one week at a temperature of 110F.
12974~ ~
62301-1385
DETAILED DESCRIPTION OF THE INVENTION
The enzyme stabilizing system of the invention is a
mixture of glycerine, a boron compound selected from among
boric acid, boric o~ide and an alkali metal borate and a car-
boxylic acid compound as herein defined. The weight of the
stabilizing system in the present built liquid de-tergent compo-
sitions is generally from about 3 to 25%, preferably about 6 to
15~, by weight. The weight ratio of glycerine to borax in the
stabilizing mixtures is generally from about 1 to 3. The pre-
ferred amount of glycerine in the composition is from about 3to 7%, the preferred amount of boron compound is from abut l to
5~, and the preferred amount of carboxylic compound is from
about 0.5 to 4% based on the weight oE the compo~ition.
The carboxylic acid compounds which are useful in khe
enyzme stabilizing system of the invention encompass saturated
as well as unsaturated mono, di and polycarboxylic acids having
1 to 8 carbon atoms among which are included oxalic acid
(~OOCCOOH), malonic acid (HOOCCH2COOH), maleic acid
(HOOCCH:CHCOOH) and succinic acid (HOOCCH2CH2COOH). The car-
boxylic acids may contain hydroxy or amino substituents asexemplified by malic acid (HOOCCHOHCH2COOH), tartaric acid
(dihydroxysuccinic acid) aspartic acid (amino succinic acid)
and citric acid. Preferred carboxylic acids of the invention
are succinic acid, maleic acid, malonic acid and malic acid.
From a commercial standpoint, a particularly preferred carboxy-
lic acid compound is citric acid and/or its salts because of
their relatively low cost.
The alkaline proteolytic enzymes suitable for the
present compositions include the various commercial liquid
enzyme preparations which have been adapted for use in
- ~c
1 297~
62301-1385
detergent compositions. Enzyme preparations in powdered form
are also useful although, as a general rule, less convenient
for incorporation into the built liquid detergent compositions.
Thus, suitable liquid enzyme preparations include "Alcalase"
and "Esperase" sold by Novo Industries, Copenhagen, Denmark,
and "Maxatase" and "AZ-Protease" sold by Gist-Brocades, Delft,
The Netherlands.
Among the suitable ~-amylase liquid enzyme prepara-
tions are those sold by ~ovo Industries and Gist-Brocades under
the tradenames "Termamyl" and "Maxamyl", respectively.
"Esperase" is particularly preferred for the present
compositions because of its optimized activity at the higher pH
values corresponding to the built dekergent compositions.
The preferred detergents for use in the present
liquid compositions are the synthetic anionic detergent com-
pounds, and particularly a mixture of higher alkylbenzene sul-
fonate and alkyl polyethoxy sulfate. While other water soluble
higher alkylbenzene sulfonates may also be present in the
instant formulas, such as potassium salts and in some instances
the ammonium or alkanolammonium salts, where appropriate, it
has been found that the sodium salt is highly preferred, which
is also the case with respect to the alkyl polyethoxy sulfate
detergent component. ~he alkylbenzene sulfonate is one wherein
the higher alkyl is of 12 to 15 carbon atoms, preferably 13
carbon atoms. The alkyl polyethoxy sulfate, which also may be
referred to as a sulfated polyethoxylated higher linear alcohol
or the sulfated condensation product of a higher fatty alcohol
and ethylene oxide or polyethoxylene glycol, is one wherein the
alkyl is of lO to 18 carbon atoms, preferaly 12 to 15 carbon
~74~
62301-1385
atoms, e.g., about 13 carbon atoms, and which includes 3 to 11
ethylene oxide groups, preferably 3 to 7, more preferably 3 to
5 and most preferably 3 or about 3 ethylene oxide groups. The
ratio of alkylbenzene sulfonate to polyethoxy sulfate in the
detergent ~ixture is preferably from abut 2:1 to 8:1 and most
preferably from about 3:1 to 5:1, by weight. At ratios above
5:1, the physical stability of the product may be adversely
affected.
In suitable circumstances other anionic detergents,
such as fatty alcohol sulfates, paraffin sulfonates, olefin
sulfonates, monoglyceride sulfates, sarcosinates and similarly
functioning detergents, preferably as the alkali metal, e.g.,
sodium salts, can be present, sometimes in partial replacement
of the previously mentioned synthetic organic detergents but
usually, if present, in addition to such detergents. Normally,
the supplementing aetergents will be sulfated or sulfonated
products (usually as the sodium salts) and will contain long
chain (8 to 20 carbon atoms) linear or fatty alkyl groups. In
addition to any supplementing anionic synthetic organic deter-
gents, there also may be present nonionic and amphoteric mater-
ials, like the Neoaols,~ sold by Shell Chemical Company,
which are condensation products of ethylene oxide and higher
fatty alcohols, e.g., Neodol~ 23-6.5, which is a condensation
product of a higher fatty alcohol of about 1~ to 13 carbon
atoms with about 6.5 moles of ethylene oxide. Illustrations of
the various detergents and classes of detergents mentioned may
be found in the text Surface Active Agents, Vol. II, by
Schwartz, Perry and Berch (Interscience Publishers, 195~), the
descriptions of which are incorporated herein by reference.
:12~79~4~
62301-1385
The builder salt combination of this invention, which
has been found to satisfactorily improve the detergency of the
mixture of synthetic anionic organic detergents and produce the
desired pH in the liquid detergent and in the wash water, is a
mixture of sodium tripolyphosphate and sodium carbonate. The
builder salts are employed in the present compositions in
amounts generally of from about 5 to 25%, by weight. For the
preferred builder salt combination, sodium tripolyphosphate is
present in amounts of from about 5 to 20~, preferably 10 to
16%, and sodium carbonate is present from about 1 to 10%, by
weight, preferably 3 to 7~, the weight ratio of tripolyphos-
phate to carbonate in the preferred builders mixtures being
from about 2:1 to 6:1, and mo~t preferably ~rom about 2:1 to
4:1. As used herein, the term alkali metal "carbonates" or
"carbonate" is meant to include the carbonates, bicarbonates
and sesquicarbonates of such alkali metal.
For best processing, easier mixing and good end-use
properties it is preferred that the sodium tripolyphosphate be
low in content of Phase I type tripolyphosphate. Thus, normal-
ly the content of Phase I type tripolyphosphate will be lessthan 30% of the tripolyphosphate employed. Although in some
instances incompletely neutralized tripolyphosphate may be
used, normally the phosphate employed may be considered as
being pentasodium tripolyphosphate, MasP301o. Of course, in
some instances, as when potassium salts of other materials are
present, ion interchange in an aqueous medium may result in
other salts than the sodium tripolyphosphate being present but
for the purpose of this specification it will be considered
that sodium tripolyphosphate, as the pen-tasodium salt, the
material which is normally charged to the mixer to make the
- lQ -
~2~7~
~2301-13~5
present liquid detergent, is the tripolyphosphate employed.
Other preferred builder salts which may be used in
place of sodium tripolyphosphate and sodium carbonate or in
addition thereto include a polyacetal carboxylate as herein
described and sodium nitrilotriacetate (NTA). Of course, vari-
ous mixtures of the mentioned water soluble builder salts can
be utilized. Yet, the tripolyphosphate-carbonate mixture des-
cribed has been found to be most preferred, although the other
builders and mixtures thereof are also operative. Other build-
ers which may be employed as supplements, in addition to theproportions of the above mentioned builders, include other
phosphates, such as tetrasodium pyrophosphate or tetrapotassium
pyrophosphatel sodium bicarbonate, sodium citrate, sodium g1uc~-
onate, sodium silicate, and sodium sesquicarbonate. Among the
water insoluble builders that may be used are the æeolites,
such as Zeolite A, usually in the ~orm of its crystalline hy-
drate, although amorphous zeolites may also be useful.
Polyacetal carboxylates are generally described in
U.S. Patents 4,144,226 and 4,315,092. U.S. Patent 4,146,495
describes detergent compositions containing polyacetal carboxy-
lates as builders.
The polyacetal carboxylates which are useful herein
as builders may be considered to be those described in U.S.
~atent 4,144,226 and may be made by the method mentioned there-
in. A typical such product will be of the formula
Rl - (fH)n ~ R2
COOM
wherein M is selected from the group consisting of alkali meta-
1, ammonium, alkyl groups of 1 to 4 carbon atoms, tetraalkyl-
ammonium groups and alkanolamine groups, both of 1 to 4 carbon
~ -- 11 --
~L2~4 ~
62301-1385
atoms in the alkyls thereof, n averages at least 4, and Rl and
R2 are any chemically stable groups which stabilize the polymer
against rapid depolymerization in al~aline solution. Prefer-
ably the polyacetal carboxylate will be one wherein M is alkali
metal, e.g., sodium, n is from 50 to 200, Rl is
CH3CH~O MOOC
HCO- or H3C-CO-
H3C MOOC
or a mixture thereof, R2 is
1~ OCH2CH3
-CH
CH3
and n averages Erom 20 to 100, more preferably 30 to ~0. The
calculated weight average molecular weights of the polymers
will normally be within the range of 2,000 to 20,000, prefer-
ably 3,500 to 10,000 and more preferably 5,000 to 9,000, e.g.,
about 8,000.
A particularly preferred sodium polyacetal carboxy-
late is supplied by Monsanto Company and is known as Builder U.
It has a calculated average molecular weight of about 8,000 and
an active polymer content of about 80%.
Although the preferred polyacetal carboxylates have
been described above, it is to be understood that they may be
wholly or partially replaced by other such polyacetal carboxy-
lates or related organic builder salts described in the pre-
viously cited patents on such compounds, processes for the
manufacture thereof and compositions in which they are employ-
ed. Also, the chain terminating groups described in the vari
ous patents, especially U.S. 4,144,226, may be utilized, pro-
viding that they have the
- - 12 -
~297~
desired stabilizing properties, which allow the mentioned
builders to be depolymerized in acidic media~ facilitating
biodegradation thereof in waste streams, but maintain their
stability in alkaline media, such as washing solutions.
The only other required component of the present
liquid detergents is water. ~ormally the har~ness content
of such water will be less than about 300 ppm., as CaC03,
and preferably it will be less than 150 ppm. Often it may
be desirable to utilize dei~nized water although city water
with less than 50 or 100 p.p.m. hardness content will frequently
be equally satisfactory.
Various adjuvants may be present in the liquid detergents,
such as fluorescent brighteners, perfumes and colorants. The
fluorescent brighteners include the well known stilbene deri-
vatives, including the cotton and nylon brighteners, such as
those sold under the trademark Tinopal (5BM Conc.). The perfumes
that are employed usually include essential oils, esters,
aldehydes and/or alcohols, all of which are known in the perfumery
art. The colorants may include dyes and water dispersible pigments
of various types, including ultramarine blue. Inorganic filler
salts, such as sodium sulfate and sodium chloride may be present,
as msy be antiredeposition agents, such as sodium carboxymethyl-
cellulose; dispersing agents, such as sodium polyacrylate;
bleaches; bactericides; fungicides; anti-foam agents, such as
silicones; anti-soiling agents, such as copolyesters; preservatives
such as formalin; foam stabilizers, such as lauric myristic die-
thanolamide; and auxiliary solvents, such as ethanol. Normally
-13-
7~
62301-1385
the individual proportions of such adjuvants will be less than
3%, often less than l~ and sometimes even less than 0.5%, ex-
cept for any filLers and solvents, and additional detergents
and builders for which the proportions may sometimes ba as high
as 10%. The total proportion of adjuvants, including non--
designated synthetic detergents and builders, will normally be
no more than 20% of the product and desirably will be less than
10% thereof, more desirably less than 5% thereof. Of course,
the adjuvants employed will be selected so as not to interfere
with the washing action of the liquid detergent and to avoid
instability of the product on standing. Also, adjuvants which
cause the production of objectiorlable deposits on the laundr~
are to be avoided.
The present liquid compositions are efficient and
easy to use. Compared to heavy duty laundry detergent powders,
much smaller volumes of the present liquids are employed to
obtain comparable cleaning of soiled laundry. For example,
using a typical preferred formulation of this invention, only
about 132 grams or l/~ cup of liquid is needed for a full tub
of wash in a top-loading automatic washing machine in which the
water volume is 15 to 18 gallons (57 to 58 liters); and even
less is needed for front-loading machines. Thus, the concen-
tration o~ the liquid detergent composition in the wash water
is on the order of about 0.2%. Usually, the proportion of the
liquid composition in the wash solution will range from about
0.05 to 0.3%t preferably from 0.15 to 0~25~o The proportions
of the various constituents of the liquid composition may vary
accordingly. Equivalent results can be obtained by using
greater proportions of a more dilute formulation but the great-
30 er quantity needed will require additional packaging and willgenerally be less convenient for consumer use and may also
result in product separation.
'~ - 14 -
1;~9~4 ~
62301-1385
The viscosity of -the present liquid detergent is
normally in -the range of about 1000 to 10,000 centipoises,
preferably 2000-5000 centipoises, but products of other
suitable viscosities may also be useful. At the viscosities
mentioned, the liquid detergent is pourableJ stable,
non-separating and uniform. The pH of the liquid detergent
suspension usually in the range of 7 to 11.5, preferably 8 to
10.5, appears to help to maintain product stability and
pourability.
10The following examples illustrate but do not limit
the invention. Unless otherwise indicated all parts are by
weight and temperatures are in C.
EXAMPLE 1
~ ent Percent
Pentasodium tripolyphosphate 15.0
Sodium carbonate 5.0
Sodium linear tridecylbenzene
sulfonate 12.2
AEOS(l) 2.8
Carboxymethyl cellulose (CMC) 0.15
Optical brightener 0.4
Perfume 0.3
Enzyme (Esperase 8.OL)(2) 1.0
Glycerine 4.0
Borax 3.0
Triethanolamine 1.0
Sodium citrate 2.0
Water and ad~uvants Balance
(1) Sodium alkyl polyethoxy sulfate wherein the alkyl is 12 to
3015 carbon atoms and the polyethoxy is 3 ethoxy groups.
(2) "Esperase" sold by Novo Industries having an activity of
8.0 KNPU/gram.
- 15 -
!
~2S~7~
The composition shown above was preyared by the following
procedure: 32.5 parts of deionized water at 40F are added to
a suitable mixing apparatus such as a vertical cylindrical tank
equipped with a stirrer. With the stirrer adjusted for medium
agitation, a mixture consisting of 5.0 parts anhydrous soda ash
and 0.17parts sodium carboxymethyl cellulose is incorporated
into the water. The stirrer speed is then increased to maximum
agitation and 15.0 parts pentasodium tripolyphosphate is slowly
added to the mixing apparatus over a period of 10-15 minutes to
form a milky white suspension. The agitation speed is then
decreased to a slow/medium setting while 19.1 parts of a high
AI (about 50%) LTBS slurry is added. Thereafter the optical
brightener/color solution is added consisting of 0.4 parts
Tinopal L~IS-X (CIBA-GEIGY), 0.06 parts bl~le dye
and 2.0 parts deionized water. Once a uniform blue colored solu-
tion is obtained, 0.3 parts of perfume are added to the mixture
under agitation. This is followed by the slow addition of 4.0
parts glycerine, 3.0 parts borax and 1.0 part triethanolamine
(the TEA improves long term product stability) as a three component
slurry. Stirring is continued until the mixture is uniform in
appearance and then 2.0 parts of sodium citrate and 4.0 parts
water are slowly added. Agitation of the mixture is then reduced
while a mixed AI detergent base consisting of 5.7 parts LTBS
slurry (about 50% AI) and 4.7 parts AEOS (about 60% AI) is added
to the mixture. This is followed by the slow addition of 1.0
part proteolytic enzyme with continous agitation until all materials
are completely dispersed or dissolved.
-16-
74 ~L
EYAMPLE 2
Enzyme-containing built liquid detergent compositions
A to G were formulated as set forth below in Table 1. The
percentages shown indicate weight percent. The arrows are
meant to indicate the extent to which Compositions B to G are
identical to Composition A.
TABLE_l
_mponent A B C D E F G
Pentasodium
Tripolyphosphate 15%
Sodium Carbonate
(anhydrous) 5
Sodium linear tridecyl-
benzene sulfonate 12.2
AEOS(1~ 2.8
Optical brightener 0.4
(Tinopal LMS-X)
Perfume 0 23 ~ ~ ~ / \
Enzyme(2) 1 , ~ ~ ~ ~
Glycerine - 4 - 4 - - 4
Borax _ _ 3 3 _ 3 3
Carboxylic acid compound - - - - 2 2 2
Water and adjuvants - Balance
~ . _
(1) Sodium alkyl polyethoxy sulfate wherein the a]kyl is
12 to 15 carbon atoms and the polyethoxy is 3 ethoxy groups.
(2) "Esperase" sold by Novo Industries having an activity of
8.0 KNPU/gm (Kilo Novo Protease units/gm)
-17-
The enzyme activities of Compositions A to G were tested
after 7 days storage at 110F. The measured enzyme activity
for each composition after this period of storage is indicated
in Table 2 and Table 3 as a percent of the initial value. The
various carboxylic acids and salts used in the formulas of
Compositions A, B~ C, D, E, and G are shown in I`able 2 as well as
the enzyme activities corresponaing to each composition.
TABLE 2
ENZYME STABILITY
Percent Active Enzyme
Composition After 7 Days at 110F
A (control) ND
B (with glycerine) ND
C (with borax) ND
D (with glycerine and borax) 45
Composition E (with carboxylic acid compound)
wherein the carboxylic acid compound is
,
(1) Succinic acid ND*
(2) Malonic acid "
(3) Malic acid "
(4) Oxalic acid "
(5) ~aleic acid "
(6) Tartatic acid "
(7) Aspartic acid "
(~S) Citric acid
(9) Glycine "
(10) Alanine "
(11) Sodium Succinate
(12) Sodium formate
(13) Sodium acetate "
(14) Sodium tartrate "
(15) Sodium citrate ll
(16) Sodium glycolate "
(17) Sodium tetrahydroxysuccinate l'
~D = not detectable (below 10% residual activity)
~g~
6230l-1385
Composition G (with glycerine/borax/carboxylic Percent Active
acid compund) wherein the carboxylic acid Enzyme After
compund is: 7 days at 110F
.... _ . _
(1) Sodium succinate 60
(2~ Succinic acid 94
(3) Malonic acid 91
~ alic acid 79
(5) Oxalic acid 81
(6) Maleic acid 88
(7) Tartaric acid 63
(8) Aspartic acid ~4
(9) Citric acid 62
(10) Glycine 80
(11) ~lanine 79
(12) Sodium acetate (comparison) 50
(13) Sodium tartrate 54
(14) Sodium citrate 57
20 (15) Sodium glycolate 50
(16) Sodium tetrahydroxy succinate ~1
As evident from Table 2, Composition A, the con-trol
composition, as well as Compositions B and C which contained
glycerine and borax, respectively, as individual stabilizers,
manifested almost no enzyme activity after the 7 day storage
period of 110F. Since enzyme activities below 10~ could not
be precisely measured they are designated "ND". Composition D
containing glycerine/borax in the absence oE a carboxylic acid
compound provided an improvement in enzyme stability relative
to Compositions A, B and C but more than 50% of the enzyme was
deactivated. The various Compositions E containing a variety
-- 19 --
,;~
12974~
62301-1385
of carboxylic acid compounds, as indicated, manifested abso-
lutely no improvement in enzyme stability relative to Composi-
tions A, B and C. However, Compositions G formulated in
accordance with the invention demonstrate the unexpected and
synergistic improvement in enzyme stability which is achieved
with the use of glycerine/borax in combination with a carboxy-
lic acid compound in the present liquid detergent compositions.
It is noted that in every one of the 17 compositions corres-
ponding to Composition G which were tested, the enzyme activity
was improved relative to Composition D (containing glycerine
and borax).
. - l9a -
7~
A comparison of the enzyme activities achieved with
Compositions D (glycerine/borax~ and various Compositions F
(borax/carboxylic acid compound) and G (formulated in accordance
with the invention) is set forth below in Table 3.
TABLE 3
ENZYME STABILITY
Percent active Enzyme After
Composition 7 Davs at 110F
D (Glycerine/borax) 45
F (Borax/malonic acid) 13
G (Glycerine/borax/malonic acid) 91
F (Borax/aspartic acid) 39
G tGlycerine/borax/aspartic acld) 84
F (Borax/citric acid) ND*
G (Glycerine/borax/citric acid) 62
* ND = not detectable (below 10% residual activity)
As shown in Table 3, the various Compositions G containing
a three component stabilizer system in accordance with the
invention provided a synergistic improvement in enzyme
stability relative to Compositions D and F formulated in
accordance with the prior art.
-20
