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Claims  |
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I claim:
1. An encapsulating enzyme composition capable of delivering active enzyme
into a solution containing an active chlorine which comprises:
(a) an enzyme core comprising a protease, a lipase, an amylase, or mixtures
thereof;
(b) a first encapsulating coating of a chlorine bleach-neutralizing
substance comprising a sulf-oxy acid or salt thereof, a peroxide producing
substance or a sugar; and
(c) a second encapsulating coating of a time-release substance comprising a
cellulose derivative.
2. The composition of claim 1 further comprising an initial encapsulating
coating of a cellulose derivative between the enzyme core and the first
coating.
3. The composition of claim 1 further comprising, in combination with the
encapsulated enzyme, a encapsulated chlorine bleach-neutralizing which
comprises:
(a) a core comprising a sulf-oxy acid or salt thereof, a peroxide producing
substance or a sugar; and
(b) an encapsulating coating of a cellulose derivative.
4. The composition of claim 1 further comprising, in combination with the
encapsulated enzyme, a separately encapsulated diluent which comprises:
(a) a diluent core comprising inorganic salt;
(b) a first encapsulating coating of a sulf-oxy acid or salt thereof, a
peroxide producing substance or a sugar; and
(c) a second encapsulating coating of a cellulose derivative.
5. The composition of claim 4 wherein the diluent is an inorganic salt
comprising sodium sulfate or sodium chloride.
6. The composition of claim 1 wherein the sulf-oxy acid or salt thereof
comprises thiosulfite, metabisulfite, bisulfite, or salt thereof.
7. The composition of claim 1 wherein the peroxide producing substance is
hydrogen peroxide, a perborate, persulfate, perphosphate, or percarbonate.
8. A cleaning composition comprising:
(a) an encapsulated enzyme which comprises:
(i) an enzyme core comprising a protease, a lipase, an amylase, or mixtures
thereof;
(ii) a first encapsulating coating of a chlorine bleach-neutralizing
substance comprising a sulf-oxy acid or salt thereof, a peroxide producing
substance or a sugar; and
(iii) a second encapsulating coating of a time-release substance comprising
a cellulose derivative;
(b) a chlorine bleach, and
(c) at least one additional detergent component selected from surfactants,
detergent fillers, detergent builders, sequestrants, and chelating agents.
9. A cleaning composition comprising:
(a) an encapsulating enzyme which comprises:
(i) an enzyme core comprising a protease, a lipase, an amylase, or mixtures
thereof;
(ii) a first encapsulating coating of a chlorine bleach-neutralizing
substance comprising a sulf-oxy acid or salt thereof, a peroxide producing
substance or a sugar; and
(iii) a second encapsulating coating of a time-release substance comprising
a cellulose derivative;
(b) an encapsulated diluent which comprises:
(i) a diluent core comprising an inorganic salt;
(ii) a first encapsulating coating of a sulf-oxy acid or salt thereof, a
peroxide producing substance or a sugar;
(iii) a second encapsulating coating of a cellulose derivative;
(c) a chlorine bleach, and
(d) at least one additional detergent component selected from surfactants,
detergent fillers, detergent builders, sequestrants, and chelating agents.
10. A cleaning composition, comprising:
(a) about 0.3-20 wt-%, based upon the cleaning composition, encapsulated
enzyme which comprises:
(i) about 1 to 95 wt-%, based upon the encapsulated enzyme, enzyme core
comprising a protease, a lipase, an amylase, or mixtures thereof;
(ii) about 1-95 wt-%, based upon the encapsulated enzyme, first
encapsulating coating of a chlorine bleach-neutralizing substance
comprising a sulf-oxy acid or salt thereof, a peroxide producing substance
or a sugar; and
(iii) about 1-50 wt-%, based upon the encapsulated enzyme, second
encapsulating coating of a time-release substance comprising a cellulose
derivative;
(b) about 0.1-40 wt-% chlorine bleach; and
(c) about 55-95 wt-%, based upon the cleaning composition, of at least one
additional detergent component selected from the group consisting of
detergent fillers, detergent builders, surfactants, sequestrants, and
chelating agents.
11. A cleaning composition comprising:
(a) about 0.3-20 wt-%, based upon the cleaning composition, encapsulated
enzyme which comprises:
(i) about 1 to 95 wt-%, based upon the encapsulated enzyme, enzyme core
comprising a protease, a lipase, an enzyme, or mixtures thereof;
(ii) about 1-95 wt-% based upon the encapsulated enzyme, first
encapsulating coating of a chlorine bleach-neutralizing substance
comprising a sulf-oxy acid or salt thereof, a peroxide producing substance
or a sugar; and
(iii) about 1-50 wt-%, based upon the encapsulated enzyme, second
encapsulating coating of a time-release substance comprising a cellulose
derivative;
(b) at least a sufficient bleach neutralizing amount of an encapsulated
diluent which comprises:
(i) about 1-95 wt-%, based upon the encapsulated diluent, of a diluent core
comprising an inorganic salt;
(ii) about 1-95 wt-%, based upon the encapsulated diluent, first
encapsulating coating of a sulf-oxy acid or salt thereof, a peroxide
producing substance or a sugar; and
(iii) about 1-50 wt-%, based upon the encapsulated diluent, second
encapsulating coating of a cellulose derivative;
(c) about 0.1-40 wt-%, based upon the cleaning composition, chlorine
bleach; and
(d) about 55-95 wt-%, based upon the cleaning composition, additional
detergent components selected from the group consisting of detergent
fillers, detergent builders, surfactants, sequestrants, and chelating
agents.
12. The cleaning composition of claim 9 wherein the hydrogen peroxide
producing substance is hydrogen peroxide, a perborate, persulfate,
perphosphate, or percarbonate.
13. The cleaning composition of claim 9 wherein the peroxide producing
substance is hydrogen peroxide, a perborate, persulfate, perphosphate, or
percarbonate.
14. An aqueous cleaning composition comprising, in an aqueous medium;
(a) an effective cleaning concentration of a rapidly soluble active
chlorine bleach in the aqueous cleaning composition; and
(b) an encapsulated enzyme comprising:
(i) an enzyme core comprising a protease, a lipase, an amylase, or mixtures
thereof;
(ii) a first encapsulating coating of a chlorine bleach-neutralizing
substance comprising a sulf-oxy acid or salt thereof, a peroxide producing
substance or a sugar; and
(iii) a second encapsulating coating of a time-release substance comprising
a cellulose derivative, wherein the cleaning composition is suited for an
end use of warewashing.
15. The composition of claim 14 further comprising an initial encapsulating
coating of a cellulose derivative between the enzyme core and the first
coating.
16. The composition of claim 14 further comprising, in combination with the
encapsulated enzyme, a separately encapsulated chlorine
bleach-neutralizing substance which comprises:
(a) a core comprising sulf-oxy acid or salt thereof, a peroxide producing
substance or a sugar; and
(b) an encapsulating coating of a cellulose derivative.
17. The composition of claim 14 further comprising in combination with the
encapsulated enzyme, a separately encapsulated diluent which comprises:
(a) a diluent core comprising an inorganic salt;
(b) a first encapsulating coating of a chlorine bleach-neutralizing
substance comprising a sulf-oxy acid or salt thereof, a peroxide producing
substance or a sugar; and
(c) a second encapsulating coating of a cellulose derivative.
18. The composition of claim 1 wherein the sulf-oxy acid or salt thereof
comprises a thiosulfite, metabisulfite, bisulfite, or salt thereof.
19. The composition of claim 14 wherein the peroxide producing substance is
hydrogen peroxide, a perborate, persulfite, perphosphate, or percarbonate.
20. The composition of claim 14 wherein the polymer comprises a cellulose
derivative.
21. A cleaning composition comprising:
(a) about 0.3-20 wt-%, based upon the cleaning composition, encapsulated
enzyme which comprises:
(i) about 1 to 95 wt-%, based upon the encapsulated enzyme, enzyme core
comprising a protease, a lipase, an amylase, or mixtures thereof;
(ii) about 1-95 wt-% based upon the encapsulated enzyme, first encapsulated
coating of a chlorine bleach-neutralizing substance comprising a sulf-oxy
acid or salt thereof, a peroxide producing substance or a sugar; and
(iii) about 1-50 wt-%, based upon the encapsulated enzyme, second
encapsulating coating of a time-release substance comprising a cellulose
derivative;
(b) about 0.1-40 wt-% chlorine bleach; and
(c) about 55-95 wt-%, based upon the cleaning composition, of at least one
additional detergent component selected from the group consisting of
detergent fillers, detergent builders, surfactants, sequestrants, and
chelating agents, wherein the cleaning composition is suited for an end
use of warewashing.
22. The cleaning composition of claim 21 wherein the peroxide producing
substance is hydrogen peroxide, a perborate, persulfate, perphosphate, or
percarbonate. |
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Claims |
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Description |
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FIELD OF THE INVENTION
The invention relates broadly to encapsulated enzymes and particularly to
water soluble encapsulated enzymes which may be combined with a halogen
bleach to form an effective bleach/enzyme cleaning composition.
BACKGROUND OF THE INVENTION
Enzymes are proteins synthesized by living organisms which can catalyze
specific biochemical reactions such as the conversion of starch to sugar
(amylase), the hydrolysis of fats to glycerol and fatty acids (lypase) and
the hydrolytic breakdown of proteins (protease). It is commonly believed
that enzymes are capable of catalyzing reactions only at a limited number
of specific sites commonly referred to as "active sites".
Certain biological materials such as proteins, lipids and polysaccharides
can be difficult to remove from substrates such as dishes, flatware and
fabrics as such biological materials are substantially insoluble in
traditional cleaning media. To increase the solubility and thereby effect
removal of such biological materials, it is known to employ an enzyme in a
cleaning media to catalytically assist in breaking down such materials
into insoluble monomeric and/or oligomeric molecules. Certain types of
enzymes such as amylase, lipase, and protease are known to be particularly
useful for such purposes as they can effectively remove such materials
from substrates without significantly degrading the substrate being
cleaned.
Halogen bleaches are a well known group of chemical compounds having the
ability to remove stains such as those caused by coffee and tea from a
substrate. Halogen bleaches eliminate such stains by breaking down the
large colored organic molecules which form such stains into smaller
colorless molecules.
The cleaning actions of enzymes and halogen bleaches are complementary,
each affecting different aspects of the soils typically found on dishes,
flatware, and fabrics. Accordingly, a superior cleaning composition could
be formed by employing both an enzyme and a halogen bleach in a single
cleaning composition. However, while simple in theory such a combination
has proven to be difficult to implement as halogen bleaches tend to
instantly deactivate enzymes at concentrations as low as 1 part active
halogen per one million parts cleaning media. While such deactivation of
enzymes is not fully understood, it is believed that the halogen bleach
affects either a change in the structure of the enzyme's active site or a
change in the shape of the enzyme such that the enzyme's active site is no
longer available as a reactor site.
Early attempts to combine a halogen bleach and an enzyme into a stable
cleaning composition included the incorporation of a stabilizing amount of
a polysaccharide into the cleaning composition, the incorporation of a
stabilizing amount of a nonionic polymer into the cleaning composition,
and coupling of the enzyme to an insoluble support. All of these early
attempts met with limited success, encouraging research into other
methods.
A slightly more successful attempt at combining a halogen bleach and an
enzyme into a stable cleaning composition comprised encapsulation of the
bleach in a time release coating. The time release coating delayed the
release of the enzyme deactivating bleach for a time period sufficient to
allow the enzyme to perform its cleaning function before it was
deactivated. Unfortunately, this attempt also met with limited success as
it proved virtually impossible to economically prevent premature release
of an enzyme deactivating amount of the bleach.
A still slightly more successful attempt at combining a halogen bleach and
an enzyme into a stable cleaning composition is disclosed in U.S. Pat. No.
4,421,664, which teaches that enzyme activity may be maintained in the
presence of a halogen bleach by encapsulating the bleach in a time release
coating and incorporating an amount of a reducing agent into the
composition sufficient to substantially instantaneously reduce all
prematurely released bleach. While this method has proven much more
successful than earlier attempts, it has been discovered that in order for
this method to work effectively it is necessary to employ an encapsulated
bleach having an extremely high encapsulation efficiency which results in
a prohibitively expensive composition.
Accordingly, a substantial need exists for an inexpensive and stable
cleaning composition containing both an enzyme and a bleach wherein both
the enzyme and the bleach may perform their desired cleaning function.
SUMMARY OF THE INVENTION
In a first aspect of my invention I have discovered a composition capable
of releasing active enzyme into an aqueous, chlorine bleach-containing
media, the composition comprising an enzyme core encapsulated with an
inner coating of a bleach-neutralizing substance and an outer coating of a
time-release substance. The encapsulated enzyme may further comprise an
initial coating of a time-release substance between the enzyme and the
bleach-neutralizing substance to ensure that all chlorine bleach present
in the solution has been neutralized by the bleach-neutralizing substance
before the enzyme is released.
In a second aspect of my invention I have discovered a composition capable
of releasing active enzyme into an aqueous, chlorine bleach-containing
media, the composition comprising an enzyme core encapsulated with a
time-release substance designed to delay release of the enzyme into
solution for a first-time delay, and a bleach-neutralizing substance
encapsulated with a time-release substance designed to delay release of
the bleach neutralizing substance into solution for a second-time delay;
the first-time delay being longer than the second- time delay so that the
bleach-neutralizing substance will be released and completely neutralize
all chlorine bleach present in the solution before the enzyme is released.
The bleach-neutralizing substance may be present either as a core material
or as an inner coating material on a diluent core. Further, the enzyme may
be encapsulated with an inner coating of bleach-neutralizing substance
between the enzyme and the time-release substance.
In a third aspect of my invention I have discovered a composition capable
of releasing active enzyme into an aqueous, chlorine bleach-containing
media, the composition comprising an enzyme core encapsulated with a
time-release substance, a diluent core encapsulated with an inner coating
of a bleach-neutralizing substance and an outer coating of a time-release
substance, and a bleach-neutralizing substance core encapsulated with a
time-release substance. The enzyme core and the bleach-neutralizing
substance core may be further encapsulated with an initial coating of a
bleach-neutralizing substance between the core and the time-release
substance. Still further, the enzyme core may be coated with the
time-release substance so as to delay release of enzyme into solution for
a first time delay, and the cores of diluent and bleach-neutralizing
substance coated with the time-release substance so as to delay release of
diluent and bleach-neutralizing substance into solution for a second time
delay; the first time delay being longer than the second time delay so
that all bleach-neutralizing substance present as either a core material
or a coating material on a diluent core will be released and completely
neutralize all chlorine bleach present in the solution before the enzyme
is released.
In a fourth aspect of my invention I have discovered a cleaning composition
particularly effective in warewashing which comprises at least one of the
encapsulated enzyme containing compositions described above, a chlorine
bleach, and at least one additional detergent component.
Commercially available enzymes typically contain a significant portion of
an inert filler such as sodium sulfate, sodium chloride, or the like.
As utilized herein, unless otherwise indicated, "wt-% enzyme" refers to the
active enzyme and any inert filler employed in combination with the
enzyme. For example, the encapsulation of a mixture of 20 mg enzyme and 60
mg inert filler with an inner coating of 10 mg bleach-neutralizing
substance and an outer coating of 10 mg time-release substance results in
an encapsulated enzyme composition comprising 80 wt-% enzyme core.
As utilized herein, "bleach" refers to any chemical agent capable of
removing the color from a substrate by oxidation.
As utilized herein, "active halogen" or "active chlorine" refers to the
halogen or chlorine actually present in the compound having a valence of
greater than -1.
For a detailed analysis of the meaning of "bleach", "active chlorine", and
"available chlorine" see White, George, Handbook of Chlorination, 1972,
pp. 188-190, which is herein incorporated by reference.
DETAILED DESCRIPTION OF THE INVENTION INCLUDING A BEST MODE
Encapsulated Enzyme
In a first aspect of my invention I have discovered a composition capable
of releasing active enzyme into an aqueous, chlorine bleach containing
media, the composition comprising an enzyme core encapsulated with an
inner coating of a bleach-neutralizing substance and an outer coating of a
time-release substance. The encapsulated enzyme may further comprise an
initial coating of a time-release substance between the enzyme and the
bleach-neutralizing substance to ensure that all chlorine bleach has been
neutralized by the bleach-neutralizing substance before the enzyme is
released.
Enzymes
Any enzyme capable of facilitating the removal of biological soil from a
substrate without substantially damaging the substrate may be usefully
employed in the present invention. Such enzymes includes proteases,
lipases, amylases, and the like. The preferred enzyme or combination of
enzymes depends upon the substrate to be cleaned and the types of soil to
be removed. For reasons of ease of handling and ease of encapsulation, the
enzyme is preferably powdered in form.
While commercially available enzymes typically contain a significant
portion of an inert filler such as sodium sulfate, sodium chloride, or the
like, I have found that the presence of such fillers does not affect the
present invention.
Proteases (including peptidases) are those enzymes which attack and break
down proteinaceous soils such as meat residue, gravy, and blood. Proteases
are classified in EC class 3, subclass 3.4. I have found the EC class
3.4.4 peptide peptido-hydrolases such as subtilopeptidase A (EC 3.4.4.16)
to be particularly effective in the cleaning composition of this
invention. A suitable protease can be purchased from Novo Industries under
the mark Esperase.RTM..
Lipases are those enzymes which attack and break down fatty soils such as
cooking oil, grease, and ice cream. Lipases also belong to EC class 3, but
are placed in subclass 3.1. I have found the EC class 3.1.1 enzymes such
as the glycerol ester hydrolases (EC 3.1.1.3) to be particularly effective
in the cleaning composition of this invention. A suitable lipase can be
purchased from Enzyme Development under the mark Lipase 30,000.
Amylases are those enzymes which can attack and break down starch,
polysaccharide, and cellulosic soils such as potatoes, rice, oatmeal, and
grass. Amylases also belong to EC class 3, but are placed in subclass 3.2.
I have found the EC 3.2.1 glycoses hydrolases such as alpha-1,
4-glucan-4-glucanohydrolase (EC 3.2.1.1), and alpha-1, 4-glucan
maltohydrolase (EC 3.2.1.2) to be particularly effective in the cleaning
composition of this invention. A suitable amylase can be purchased from
Novo Industries under the mark Termamyl.RTM..
An in depth and detailed discussion of suitable enzymes can be found in
U.S. Pat. No. 4,421,664, column 4, line 16 through column 6, line 24,
which disclosure is herein incorporated by reference.
The encapsulated enzyme can comprise from a trace up to about 95 wt-%,
based upon the total capsule, enzyme core. However, to allow sufficient
bleach-neutralizing substance to be introduced into solution and to
achieve an economical balance between encapsulation efficiency and amount
of coating substance employed, the capsule preferably comprises about 50
to 80 wt-% enzyme.
Bleach-Neutralizing Substance
In the first aspect of my invention, surrounding and protectively
encapsulating the enzyme core is an inner coating of a bleach-neutralizing
substance which, when released into solution, reduces all active chlorine
present in the solution to a form which will not deactivate the enzyme.
The bleach-neutralizing substance should, of course, be a stable solid at
room temperature and be compatible with the enzyme and all other
components intended to be combined with the encapsulated enzyme. Further,
the bleachneutralizing substance should not damage the substrate to be
cleaned.
Any composition capable of reducing active chlorine to a form which will
not deactivate an enzyme and which meets the criteria set forth above, can
be usefully employed in the present invention. Suitable
bleach-neutralizing substances include sulf-oxy acids and salts thereof,
hydrogen peroxide producing compounds, sugars, and the like.
Sulf-oxy acids and the salts thereof are a well-known group of compounds
which possess the ability to neutralize chlorine bleaches. For reasons of
low cost, high performance, and ease of availability, the alkali metal and
ammonium salts of sulf-oxy acids, such as ammonium sulfite
((NH.sub.4).sub.2 SO.sub.3), sodium bisulfite (Na.sub.2 SO.sub.3), sodium
thiosulfite (Na.sub.2 S.sub.2 O.sub.3), sodium metabisulfite (Na.sub.2
S.sub.2 O.sub.3), potassium metabisulfite (K.sub.2 S.sub.2 O.sub.5),
lithium hydrosulfite (Li.sub.2 S.sub.2 O.sub.4), and the like are
preferred. Sulf-oxy acids are readily available from a number of suppliers
including Allied Corporation under the mark Sulftech.RTM..
Because of their odorless and noncorrosive nature, the preferred chlorine
bleach-neutralizing substances are those compounds capable of producing
hydrogen peroxide when placed in solution. Such compounds include
perborates, percarbonates, perphosphates, persulfates, and the like. These
compounds are readily available from a number of suppliers including
Interox Peroxid-Chemie GmbH and Dupont. For reasons of cost and ease of
availability, the preferred hydrogen peroxide producing source is sodium
perborate monohydrate available from Interox Peroxid-Chemie GmbH.
The encapsulated enzyme can comprise about 1 to 95 wt-%, based upon the
total capsule, bleach-neutralizing substance. However, to achieve an
economical balance between encapsulation efficiency and amount of coating
substance employed and provide sufficient bleach-neutralizing substance to
ensure complete neutralization of all active chlorine present in solution,
the capsule preferably comprises about 10 to 60 wt-%, based upon the total
capsule, bleach-neutralizing substance.
Time-Release Substance
In the first aspect of my invention, surrounding and protectively
encapsulating the enzyme core and the first coating of bleach-neutralizing
substance is an outer coating of a time-release substance. The
time-release substance delays release of the bleach-neutralizing substance
and the enzyme so that a bleach, used in combination with the capsule, can
perform its cleansing function before it is deactivated by the
bleach-neutralizing substance. The time-release substance should, of
course, be compatible with the enzyme, the bleach-neutralizing substance,
and all other components intended to be combined therewith. Further, the
time-release substance should not damage the substance to be cleaned. Any
material meeting these two criteria and capable of delaying the release of
substantial amounts of the bleach-neutralizing substance for about 1 to 20
minutes, preferably about 2 to 6 minutes may be employed in the present
invention.
Generally, the time-release substance will comprise a high molecular weight
semisolid or solid fat, an inorganic solid, a natural or synthetic
polymer, or the like. For reasons of excellent film formation, the
preferred time-release substances are the natural and synthetic polymers.
Suitable time-release polymers are well known in the art and include:
cellulose derivatives such as sodium carboxymethyl cellulose, sodium
hydroxyethyl cellulose, ethyl cellulose, hydroxypropyl cellulose,
hydroxypropyl methyl cellulose, nitro cellulose, cellulose acetate
phthalate, and hydroxypropyl methyl cellulose phthalate; gelatin; starch;
proteins; fatty acids; waxes (including paraffin and microcrystalline
waxes); polyacrylamide; polyacrylic acid; polyvinyl alcohol; polyethylene
glycol, etc. The use of these and other similar time-release substances,
including selection of an appropriate compound for a particular use, is
well within the skill of one of ordinary skill in the art.
Because of its ability to suspend soils in solution in addition to its
time-release characteristics, the preferred time-release substance is
carboxymethyl cellulose and salts thereof. Suitable sodium carboxymethyl
cellulose is available from a number of suppliers, including Hercules,
Inc., under the mark CMC-CLT.RTM..
The encapsulated enzyme can comprise about 1-50 wt-%, based upon the total
capsule, time-release substance. The preferred wt-% depends upon the
particular substance employed and how long the bleach is to be allowed to
function before it is deactivated by the bleach-neutralizing substance.
For use in ware and fabric washing, I have found that about 1-20 wt-%,
based upon the total capsule, time-release substance is typically
satisfactory.
Initial Time-Release Substance
Optionally, the encapsulated enzyme can comprise an initial coating of a
time-release substance between the enzyme core and the bleach-neutralizing
substance to ensure that all of the active chlorine in solution has been
neutralized by the bleach-neutralizing substance before the enzyme is
released.
While I have found that excellent results may be obtained in the absence of
this initial coating, it may be useful in some cases such as when an
unstable enzyme is employed, a slow reacting reducing agent is employed or
a small amount of reducing agent is employed. The initial coating of
time-release substance can comprise any of the time-release substances
previously described.
The amount of initial coating required to ensure that all active chlorine
has been deactivated before the enzyme is released depends upon the
amounts and type of bleach-neutralizing substance and initial coating
material employed. However, I have found that about 0.5 to 5 wt-%, based
upon the total capsule, initial coating material is typically sufficient
to prevent premature release.
Combination of Encapsulated Enzyme and Encapsulated Bleach-Neutralizing
Substance
In a second aspect of my invention I have discovered a composition which
comprises an enzyme encapsulated in a time-release substance designed to
delay release of the enzyme into solution for a first-time delay, and a
bleach-neutralizing substance encapsulated in a time-release substance
designed to delay release of the bleach-neutralizing substance into
solution for a second-time delay; the first-time delay being longer than
the second-time delay so that the bleach-neutralizing substance will be
released and completely neutralize all active chlorine present in the
solution before the enzyme is released. The bleach-neutralizing substance
may be present either as a core material or as a first coating on a
diluent core. Further, the enzyme may be encapsulated with an inner
coating of a bleach-neutralizing substance between the enzyme and the
time-release substance. Still further, the enzyme may be initially
encapsulated with a time-release substance.
Diluent
A diluent core may be employed as a carrier for bleach-neutralizing
substance wherein the bleach-neutralizing substance is coated onto the
diluent. This is particularly useful when the bleach-neutralizing
substance does not readily form substantially uniform granules. The use of
a diluent core allows both enzyme and diluent to be simultaneously coated
with bleach-neutralizing substance, thereby simplifying manufacture.
Suitable diluents include sodium sulfate, sodium chloride, etc.
The enzymes, chlorine bleach-neutralizing substances, time-release
substances, and chlorine bleaches described previously with respect to the
first aspect are all equally well suited for use in this aspect. The
time-release substance employed to coat the enzyme and the
bleach-neutralizing substance may be the same or different. For ease of
manufacturing, they are preferably the same.
This composition is particularly useful when the ratio of chlorine
bleach-neutralizing substance to enzyme is so large that there simply is
not sufficient enzyme particles upon which to attach sufficient chlorine
bleach-neutralizing substance.
Generally, the time-release layers should be designed to prevent release of
the bleach-neutralizing substance for at least about 1 minute, preferably
about 2 to 6 minutes, and the enzyme should be protectively encapsulated
for an additional 0.5-2 minutes after release of the chlorine
bleach-neutralizing substance.
In this aspect the encapsulated enzyme particle can comprise from a trace
up to about 95 wt-%, preferably about 30-80wt-% enzyme, about 0 to 10
wt-%, preferably about 0 to 5 wt-% initial coating of time-release
substance, about 0 to 95 wt-%, preferably about 10 to 60 wt-%,
bleach-neutralizing substance, and about 1-50 wt-%, preferably about 1-20
wt-% outer coating of time-release substance; and the encapsulated
chlorine bleach-neutralizing substance can comprise from a trace up to
about 95 wt-%, preferably 50 to 80 wt-% diluent core, from a trace up to
about 95 wt-%, preferably about 50-80 wt-% chlorine bleach-neutralizing
substance if employed as the core or about 15-40 wt-% chlorine
bleach-neutralizing substance if employed as the first coat, and about
1-50 wt-%, preferably about 1-20 wt-% time-release substance.
Combination of Encapsulated Enzyme, Encapsulated Bleach-Neutralizing
Substance and Encapsulated Diluent Having a Coating of Bleach-Neutralizing
Substance
In a third aspect of my invention I have discovered a composition which
comprises an enzyme core encapsulated with a time-release substance, a
diluent core encapsulated with an inner coating of a bleach-neutralizing
substance and an outer coating of a time-release substance, and a
bleach-neutralizing substance core encapsulated with a time-release
substance. Further, the enzyme and the bleach-neutralizing substance cores
may be encapsulated with an inner coating of a bleach-neutralizing
substance between the core and the time-release substance. Still further,
the time-release coating on the enzyme core may be designed to delay
release of the enzyme into solution for a first time delay, and the
time-release coating on the diluent core and the bleach-neutralizing
substance core designed to delay release of the diluent and the
bleach-neutralizing substance into solution for a second time delay
wherein the first time delay is longer than the second time delay such
that the bleach-neutralizing substance core and coatings will be released
and completely neutralize all active chlorine present in the solution
before the enzyme is released.
The enzymes, chlorine bleach-neutralizing substances, time-release
substances, and chlorine bleaches described previously with respect to the
first aspect are all equally well suited for use in this aspect. The
time-release substance and bleach-neutralizing substance employed to coat
the enzyme, the bleach-neutralizing substance and the diluent may be the
same or different. For ease of manufacturing, they are preferably the
same.
This composition is particularly useful when the ratio of chlorine
bleach-neutralizing substance to enzyme is so large that there is
insufficient enzyme particles upon which to attach sufficient chlorine
bleach-neutralizing substance.
Generally, when encapsulating the enzyme, bleach-neutralizing substance and
diluent to achieve early release of the bleach-neutralizing substance, the
time-release layers should be designed to prevent release of
bleach-neutralizing substance for at least about 1 minute, preferably
about 2 to 6 minutes, and the enzyme should be protectively encapsulated
for an additional 0.5-2 minutes after release of all of the
bleach-neutralizing substance into solution.
In this aspect the encapsulated enzyme particle can comprise from a trace
up to about 95 wt-%, preferably about 30-80 wt-% enzyme, about 0 to 10
wt-%, preferably about 0 to 5 wt-% initial coating of the time-release
substance, about 0 to 95 wt-%, preferably about 10 to 60 wt-%,
bleach-neutralizing substance, and about 1-50 wt-%, preferably about 1-20
wt-% outer coating of time-release substance; the encapsulated chlorine
bleach-neutralizing substance can comprise about 50-80 wt-% chlorine
bleach-neutralizing substance core, about 0-40 wt-% chlorine
bleach-neutralizing substance coating, and about 1-50- wt-%, preferably
about 1-20 wt-% time-release substance; and the encapsulated diluent can
comprise about 30-80wt-% diluent core, 10-60 wt-% chlorine
bleach-neutralizing substance and about 1-50 wt-%, preferably about 1-20
wt-%, time-release substance.
I have found a particularly easy and effective method of making
encapsulated enzyme and bleach-neutralizing substance which achieves the
desired order of release, the method comprising the steps of obtaining a
diluent and a bleach-neutralizing substance having a granular size
substantially the same as the enzyme granules, simultaneously coating the
enzyme, diluent and bleach-neutralizing substance granules with a
bleach-neutralizing substance, and then coating the once-coated granules
with a time-release substance.
Cleaning Composition
In a fourth aspect of my invention, the compositions of the first, second
and/or third aspects are combined with a chlorine bleach and at least one
additional detergent component to form an effective cleaning composition.
The chlorine bleach should be able to dissolve rapidly so that it may
perform its cleaning function before the chlorine bleach-neutralizing
substance is released. Many of the well-known chlorine bleaches are
rapidly soluble and would be suitable for use in the invention.
Chlorine bleaches are a well-known group of compounds capable of releasing
active chlorine (Cl.sub.2) or hypochlorite (OCL--) ions into solution.
Suitable chlorine bleaches include alkali metal dichloroiso- cyanurates,
chlorinated trisodium phosphate, alkali metal and alkaline earth metal
hypochlorites, monochloramine, dichloramine, nitrogen trichloride,
[(mono-tri-chloro)-tetra-(mono-potassium dichloro)]penta-isocyanurate,
1,3-dichloro-5,5-dimethyl hydantoin, paratoluene sulfondi-chloroamide,
trichlomelamine, N-chloromelamine, N-chlorosuccinimide,
N,N'-dichloroazodicarbonamide, N-chloro acetyl urea, N,N'-dichlorobiuret,
chlorinated dicyandiamide, trichlorocyanuric acid, dichlorogly- coluril,
and the like. For reasons of excellent bleaching performance, the
preferred bleaches are hydrated and anhydrous sodium dichlorisocyanurate
and chlorinated trisodium phosphate. These bleaches are available from a
number of commercial sources including Olin Corporation under the mark
Clearon CDB-56 (sodium dichloroisocyanurate dihydrate) and Monsanto
Industrial Chemical Co. under the mark ACL-56.
While the cleaning composition can comprise only chlorine bleach and
encapsulated enzyme, for reasons of increased cleaning ability it
preferably further comprises at least one additional detergent component
such as a surfactant, a detergent filler, a detergent builder, a
sequestrant, a chelating agent, etc.
Suitable organic surfactants include anionic, nonionic, amphalytic,
zwitterionic, and mixtures thereof. While any compatible surfactant may be
employed, surfactant types which are most widely used in detergent
compositions include soaps (i.e., sodium or potassium salts) of fatty
acids, rosin acids, and tall oil; alkylarenesulfonates; alkyl sulfates,
including surfactants with both branched-chain and straight-chain
hydrophobes, as well as primary and secondary sulfate groups; sulfates and
sulfonates containing an intermediate linkage between the hydrophobic and
hydrophilic groups, such as the fatty acylated methyl taurides and the
sulfated fatty monoglycerides; long-chain acid esters of polyethylene
glycol, particularly the tall oil ester; polyethylene glycol ethers of
alkyl phenols; polyethylene glycol ethers of long-chain alcohols and
mercaptans; fatty acyl diethanolamides; and block copolymers of ethylene
oxide and propylene oxide.
Suitable detergent fillers, builders, sequestrants, and chelating agents
include any of these well-recognized components whose functions include
maintaining an alkaline pH, suspending particulate matter in solution,
preventing redeposition of particulate matter, etc. A nonexhaustive list
of such detergent fillers, builders, sequestrants and chelating agents
includes condensed phosphates such as sodium tripolyphosphate, alkalis
such as sodium carbonate, sodium metasilicate, and sodium hydroxide,
fillers such as sodium sulfate, sodium bicarbonate and sodium chloride,
soil suspending agents such as carboxymethylcellulose, and chelators such
as ethylene diamine tetraacetic acid and polyacrylic acid.
The cleaning composition can comprise: about 0.1-1.5 wt-%, preferably about
0.5 to 1 wt-% available chlorine, about 0.3 to 20 wt-%, preferably about
1.5 to 15 wt-% encapsulated enzyme; an excess stoichiometric amount of an
encapsulated bleach-neutralizing substance for the active chlorine, and
about 0 to 99 wt-%, preferably about 55 to 95 wt-% additional | | |
