FIELD OF THE INVENTION
[0001] The present invention relates to a nonaqueous liquid automatic dishwasher detergent
composition having improved cleaning performance against difficult to remove soils.
The present invention is more particularly directed to a stable nonaqueous liquid
composition containing a dual bleach system for use in an automatic dishwasher to
clean dishware, glassware, cookware and the like.
[0002] The dishwashing compositions are concentrated and comprise an organic carrier liquid,
a surfactant and a stable suspension of a builder salt. The detergent compositions
of the present invention are stable in storage and are readily pourable.
[0003] The present invention relates to an improved nonaqueous liquid dual bleach composition
and to a method of making and using the composition.
BRIEF DESCRIPTION OF THE INVENTION
[0004] The present invention is directed to a nonaqueous liquid automatic dishwasher detergent
composition having improved cleaning performance for proteinaceous and carbohydrate
soils. The liquid detergent composition contains a chlorine bleach source and a bromide
source. The detergent composition more particularly contains a source of hypochlorite
ion and a source of bromide ion.
[0005] When the detergent composition is added to a wash bath a portion of the hypochlorite
ion reacts in situ with the bromide ion to form hypobromite ion which is a powerful
oxidizing agent.
[0006] The newly formed hypobromite ion is an effective agent for cleaning carbohydrate
soils and the remaining unreacted hypochlorite ion is an effective agent for cleaning
proteinaceous soils.
[0007] The present invention specifically relates to liquid automatic dishwashing detergent
concentrate compositions having improved cleaning performance against proteinaceous
and starchy carbohydrate soils on dishware, glassware, cookware and the like, particularly
cooked on and baked on soils.
[0008] The nonaqueous liquid compositions are stable in storage, do not settle, are pourable
and are readily dispersed in water.
PRIOR ART
[0009] Commercially available household-machine dishwasher detergents provided in powder
or liquid form have the disadvantage of not being effective in cleaning both proteinaceous
and starchy carbohydrate soils. The cooked on and baked on proteinaceous and starchy
carbohydrate soils are particularly hard to remove. Though some detergent compositions
have been found to be effective in removing proteinaceous soils and others have been
found effective in removing starchy carbohydrate soils, none have been found effective
in removing both proteinaceous and starchy carbohydrate soils from dishware, glassware,
cookware and the like.
[0010] For effective use, it is generally recommended that the automatic dishwashing detergent,
hereinafter also designated ADD, contain (1) sodium tripolyphosphate (NaTPP) to soften
or tie up hard-water minerals and to emulsify and/or peptize soil; (2) sodium silicate
to supply the alkalinity necessary for effective detergency and to provide protection
for dishware, such as fine china and protection against machine corrosion; (3) sodium
carbonate, generally considered to be optional, to enhance alkalinity; (4) a chlorine-releasing
agent to aid in cleaning; (5) a surfactant and (6) a defoamer to reduce foam, thereby
enhancing machine efficiency. See, for example, SDA Detergents in Depth, "Formulations
Aspects Of Machine Dishwashing," Thomas Oberle (1974). Cleansers approximating to
the afore-described compositions are mostly liquids or powders. Generally, such compositions
omit hypochlorite bleach, since it tends to react with other chemically active ingredients,
particularly surfactant, thereby impairing its effectiveness.
[0011] The most difficult food soils to remove from dishware, cookware and utensils are
proteinaceous and starchy carbohydrate soils. The proteinaceous soils can be in the
form of baked on or cooked on milk, meats and egg soils. The starchy carbohydrate
soils can be in the form of baked on or cooked on starchy carbohydrates such as pasta,
oatmeal, porridge, bread, cake and the like.
[0012] These two types of food soils are very tenaciously bound to the dishware, cookware
and utensil substrates and are very difficult to clean without scrubbing.
[0013] Proteinaceous materials, for example, egg protein can be removed by appropriate concentrations
of, for example, sodium hypochlorite bleach. However, dishwasher detergent compositions
containing hypochlorite ion perform poorly on starchy carbohydrate soils.
[0014] The hypobromite ion is a strong oxidizing agent, but is so reactive that it is chemically
unstable in aqueous detergent compositions. Bromide ion when contacted with hypochlorite
in an aqueous alkaline medium wash bath reacts to form hypobromite. The hypobromite
effectively degrades starchy carbohydrates.
[0015] However, if too much bromide ion is present in the wash bath, it will substantially
reduce the hypochlorite ion concentration and/or will completely remove the hypochlorite
from the wash bath and the proteinaceous soils are not removed.
[0016] If an insufficient amount of bromide ion is present the starchy carbohydrate soils
are not removed.
[0017] The problem to be solved was to formulate a nonaqueous liquid dishwasher detergent
composition that was stable in storage and was effective in a wash bath in removing
both proteinaceous and starchy carbohydrate soils.
[0018] In the Diez USP 3,519,569 there is disclosed an abrasive scouring cleaner containing
as essential ingredients a water insoluble siliceous abrasive material, a hypochlorite-chlorine
liberating compound, a water soluble detergent compound and an alkali metal bromide.
[0019] The Finck USP 4,102,799 discloses an alkaline automatic dishwasher detergent composition
which is essentially free of inorganic phosphates and which consists essentially of
a citrate compound, and one or more inorganic builder salts such as silicates, carbonates
and/or sulfate. The composition can also contain one or more bleaching agents which
are capable of liberating hypochlorite chlorine and/or hypobromite bromine on contact
with aqueous media.
[0020] The Hartman European Patent Application No. 0,186,234 discloses an automatic dishwasher
powder detergent composition comprising a detergent builder, a source of hypochlorite,
a low-sudsing nonionic surfactant, an anti-sudsing agent and an alkali metal or alkaline
earth metal bromide.
[0021] The Laitem et al USP 4,753,748 discloses a nonaqueous liquid automatic dishwashing
detergent composition comprising a liquid nonionic surfactant containing a stable
or readily redispersible suspension of a polyphosphate builder and/or citrate salt
and an alkylene glycol mono alkyl ether anti-gel agent.
ADVANTAGES OVER THE PRIOR ART
[0022] The nonaqueous liquid detergent compositions of the present invention overcome many
of the prior art problems. Because of the addition of a small effective amount of
a bromide to the compositions, which generates hypobromite in the wash bath the composition
can be used to remove both proteinaceous and starchy carbohydrate soils from dishware,
glassware, cookware and the like.
[0023] In accordance with the present invention a stable nonaqueous liquid dishwashing detergent
composition containing a balanced source of hypochlorite ion and hypobromite ion is
advantageously provided such that the composition efficiently and effectively cleans
both proteinaceous and starchy carbohydrate soils from dishware, glassware, cookware
and utensils in an automatic dishwashing machine.
[0024] The nonaqueous liquid automatic dishwashing detergent compositions of the present
invention have the advantages of being stable, nonsettling in storage, and non-gelling
in storage, and are readily dispersible in the dishwashing machine. The liquid compositions
of the present invention are easily pourable, easily measured and easily put into
dishwashing machines and are readily soluble in the wash water in the dishwashing
machines.
[0025] Further, because the dishwashing machines as built and marketed have a built in volume
space in which the detergent is placed, the highly concentrated nature of the liquid
detergent concentrate composition of the present invention allows placing in the dishwashing
machine more active liquid nonionic surfactant detergent and more dispersed polyphosphate
and other detergent builders.
OBJECTS OF THE PRESENT INVENTION
[0026] It is an object of the present invention to provide a nonaqueous liquid automatic
dishwasher detergent composition that has improved cleaning performance against difficult
to remove proteinaceous and starchy carbohydrate soils.
[0027] It is another object of the invention to provide a nonaqueous liquid detergent concentrate
composition which is stable in storage, does not degrade or decompose, is easily pourable,
is readily dispersible and is readily soluble in the dishwashing water.
[0028] Another object of the present invention is to prepare a nonaqueous automatic dishwasher
detergent composition which contains both a chlorine bleach source and a bromide source.
[0029] Another object of the present invention is to prepare a nonaqueous liquid automatic
dishwasher detergent composition which on addition to a wash bath generates a balanced
amount of hypochlorite ions and hypobromite ions, which are strong oxidizing agents
and together are effective in cleaning both proteinaceous and starchy carbohydrate
soils.
[0030] A further object of the invention is to provide a method of washing dishware, glassware,
cookware and the like in an automatic dishwashing machine using a nonaqueous liquid
dual bleach system detergent composition which is effective in removing both proteinaceous
and starchy carbohydrate soils.
[0031] A still further object of the invention is to provide a method of washing dishware,
glassware, cookware and the like in an automatic washing machine using a nonaqueous
liquid nonionic surfactant detergent composition by which method both proteinaceous
and starchy carbohydrate soils are efficiently and effectively removed from dishware,
glassware, cookware and the like.
[0032] It is a further object of this invention to provide stable nonaqueous liquid detergent
dual bleach compositions, especially automatic dishwasher detergent compositions,
by incorporating in the compositions a source of chlorine bleach and a small effective
amount of bromide compound.
DETAILED DESCRIPTION OF THE INVENTION
[0033] These and other objects of the invention which will become more readily understood
from the following detailed description of the invention and preferred embodiments
thereof are achieved by incorporating in the nonaqueous liquid detergent composition
a source of chlorine bleach and a small but effective amount of bromide as the dual
bleach system.
[0034] In accordance with the present invention there is provided a nonaqueous liquid automatic
dishwasher detergent composition which includes, on a weight basis;
(a) 20 to 60% carrier liquid;
(b) 0.1 to 12% chlorine bleach stable, water dispersible organic surfactant detergent
active material;
(c) 20 to 60% organic or inorganic builder salt;
(d) 5 to 30% sodium sillcate;
(e) chlorine bleach compound in an amount to provide 0.5 to 10% available chlorine;
(f) 0.1 to 6.0% bromide compound;
(g) 0 to 25% alkali metal carbonate; and
(h) 0 to 6% chlorine bleach stable foam depressant.
[0035] The mole ratio of the bromide to available chlorine is critical and is 0.04 to 0.12.
[0036] The present invention also provides a method for cleaning dishware, glassware and
cookware in an automatic dishwashing machine with an aqueous wash bath containing
an effective amount of the automatic dishwasher detergent (ADD) nonaqueous liquid
composition as described above. According to this aspect of the invention, the ADD
composition is stable in storage, is easily measured and can be readily poured into
the automatic dishwashing machine.
[0037] The invention will now be described in greater detail by way of specific embodiments
thereof.
[0038] In accordance with the present invention an improved automatic dishwasher detergent
composition is prepared by incorporating small amounts of a bromide containing compound
in a nonaqueous liquid dishwasher composition containing an organic carrier liquid,
a surfactant and a source of hypochlorite ion. When the dishwasher detergent composition
is added to an aqueous wash bath the bromide reacts with a portion of the hypochlorite
and the bromide is converted to hypobromite, a strong oxidizing agent.
[0039] The present invention is based upon the discovery that substantially improved cleaning
performance for both proteinaceous and starchy carbohydrate soils can be obtained
by adding to a nonaqueous liquid detergent composition a source of hypochlorite and
a small effective amount of a bromide compound which when the detergent composition
is added to the aqueous wash bath form a hypochlorite and hypobromite dual bleach
system.
[0040] In accordance with an embodiment the present invention a nonaqueous liquid automatic
dishwashing detergent concentrate composition is prepared by dispersing a polyphosphate
builder in an organic carrier liquid. The polyphosphate builder may be replaced in
whole or in part by organic detergent builders such as alkali metal citrates or tartrates.
[0041] In addition other ingredients can be added to the composition such as anti-encrustation
agents, anti-foam agents, optical brighteners, enzymes and perfume.
Organic Carrier Liquids
[0042] The organic carrier liquids that can be used in accordance with the present invention
are the carrier liquids, diluents and solvents that are conventionally used in formulating
dishwasher detergents compositions. Suitable organic carrier liquids are propylene
glycol, propylene carbonate, polypropylene glycol M.W. 200, polypropylene glycol M.W.
300, methoxy propylene glycol, Carbowax MPEG 350 (polyethylene glycol methyl ether),
from Union Carbide, triethanol amine, Butyl Carbitol, from DuPont Co, Glyme (ethylene
glycol dimethyl ether), Diglyme (diethylene glycol dimethyl ether).
[0043] There can also be used as organic carrier liquids the alkylene glycol monoalkyl ethers.
The alkylene glycol mono alkyl ethers are low molecular weight amphiphilic compounds,
particularly a mono-, di- or tri lower (C₂ to C₃) alkylene glycol mono lower (C₁ to
C₅) alkyl ether. Suitable examples of such additive amphiphilic compounds are ethylene
glycol monoethyl ether (C₂H₅-O-(CH₂CH₂OH), diethylene glycol monobutyl ether (C₄H₉-O-(CH₂CH₂O)₂H)
and dipropylene glycol monomethyl ether
[0044] The above discussed organic carrier liquids can be used alone or in admixture in
order to obtain a desired viscosity and stability of the product liquid.
[0045] The compositions of the present invention have good viscosity and stability characteristics
and remain stable and pourable at low temperatures.
Surfactant Detergents
Nonionic Surfactant Detergents
[0046] The liquid nonionic surfactant detergents that can be used in the practice of the
present are preferably the low foam surfactants.
[0047] A preferred class of the nonionic detergent employed is the poly-lower alkoxylated
higher alkanol wherein the alkanol is of 9 to 18 carbon atoms and wherein the number
of mols of lower alkylene oxide (of 2 or 3 carbon atoms) is from 3 to 12. Of such
materials it is preferred to employ those wherein the higher alkanol is a higher fatty
alcohol of 9 to 11 or 12 to 15 carbon atoms and which contain from 5 to 8 or 5 to
9 lower alkoxy groups per mol. Exemplary of such compounds are those wherein the alkanol
is of 12 to 15 carbon atoms and which contain about 7 ethylene oxide groups per mol.
[0048] Useful nonionics are represented by the low foam Plurafac series from BASF Chemical
Company which are the reaction product of a higher linear alcohol and a mixture of
ethylene and propylene oxides, containing a mixed chain of ethylene oxide and propylene
oxide, terminated by a hydroxyl group. Examples include a C₁₃-C₁₅ fatty alcohol condensed
with 6 moles ethylene oxide and 3 moles propylene oxide, a C₁₃-C₁₅ fatty alcohol condensed
with 7 moles propylene oxide and 4 moles ethylene oxide and a C₁₃-C₁₅ fatty alcohol
condensed with 5 moles propylene oxide and 10 moles ethylene oxide.
[0049] Other useful surfactants are Neodol 25-7 and Neodol 25-6.5, which products are made
by Shell Chemical Company, Inc. The former is a condensation product of a mixture
of higher fatty alcohols averaging about 12 to 15 carbon atoms, with about 7 mols
of ethylene oxide and the latter is a corresponding mixture wherein the carbon atom
content of the higher fatty alcohol is 12 to 13 and the number of ethylene oxide groups
present averages about 6.5. The higher alcohols are primary alkanols. Other examples
of such detergents include Tergitol 15-S-7 and Tergitol 15-S-9 (registered trademarks),
both of which are linear secondary alcohol ethoxylates made by Union Carbide Corp.
The former is mixed ethoxylation product of 11 to 15 carbon atoms linear secondary
alkanol with seven mols of ethylene oxide and the latter is a similar product but
with nine mols of ethylene oxide being reacted.
[0050] A preferred nonionic surfactant is available from Union Carbide Corporation under
the trademark Tergitol MDS-42. This nonionic surfactant is a C₁₂-C₁₄ linear alcohol
containing 55% by weight random distributed oxyalkyl groups of which 42% are ethoxy
and 58% propoxy groups. Another nonionic surfactant that can be used is Alfonic 18-57.
[0051] Other useful nonionic surfactants are the Poly-Tergent S-LF surfactants available
from Olin Corporation. These surfactants are low foaming, biodegradable alkoxylated
linear fatty alcohols. Surfactants of this type are available under the tradenames
Poly-Tergent S-LF 18, Poly-Tergent S-305-LF, Poly-Tergent S-405-LF and Poly-Tergent
CS-1.
[0052] The use of the low foam nonionic surfactant, in the formulations is important in
avoiding cavitation problems during the wash cycle. The use of the low foam nonionics
is accordingly preferred.
[0053] Mixtures of two or more of the liquid surfactants can be used and in some cases advantages
can be obtained by the use of such mixtures.
[0054] The detergent active materials used herein are selected to be stable in the presence
of the other ingredients of the composition. In addition to the above discussed nonionic
surfactants, anionic surfactants can also be used.
Anionic Surfactants
[0055] The anionic surfactants that can be used are the linear or branched alkali metal
mono- and/or di-(C₈₋₁₄) alkyl diphenyl oxide mono and/or disulphonates, commercially
available for example as DOWFAX (Registered Trademark) 38-2 and DOWFAX 2A-1.
[0056] Other suitable surfactants include the primary alkylsulphates, alkylsulphonates,
alkylaryl-sulphates and sec. alkylsulphates. Examples include sodium C₁₀₋₁₈ alkylsulphates
such as sodium dodecylsulphate and sodium tallow alcoholsulphate; sodium C₁₀₋₁₈ alkanesulphonates
such as sodium hexadecyl-1-sulphonate and sodium C₁₂₋₁₈ alkylbenzenesulphonates such
as sodium dodecylbenzenesulphonates. The corresponding potassium salts may also be
employed.
[0057] The nonionic and anionic surfactants are used in amounts of 0.5 to 12%, for example
about 1.0 to 10%, preferably about 1.0 to 7.0%.
Chlorine Bleach Compounds
[0058] Hypochlorite generating compounds suitable for use in the compositions of the present
invention are those water soluble dry solid materials which generate hypochlorite
ion on contact with, or dissolution in, water. Examples thereof are the dry, particulate
heterocyclic N-chlorimides such as trichlorocyanuric acid, dichlorocyanuric acid and
salts thereof such as sodium dichlorocyanurate and potassium dichlorocyanurate. The
corresponding dichloroisocyanuric and trichloroisocyanic acid salts can also be used.
Other N-chloroimides may be used such as N-chlorosuccinimide, N-chloromalonimide,
N-chlorophthalimide and N-chloronaphthalimide. Additional suitable N-chloroimides
are the hydantoins such as
1,3-dichloro-5,5-dimethylhydantion;
N-monochloro-C,C-dimethylhydantoin;
methylene-bis (N-chloro-C,C-dimethylhydantoin);
1,3-dichloro-5-methyl-5-isobutylhydantoin;
1,3-dichloro-5-methyl-5-ethylhydantoin;
1,3-dichloro-5,5-diisobutylhydantoin;
1,3-dichloro-5-methyl-5-n-amylhydantoin;
and the like. Other useful hypochlorite-liberating agents are trichloromelamine and
dry, particulate, water soluble anhydrous inorganic salts such as calcium and lithium
hypochlorite. The hypochlorite liberating agent may, if desired, be a stable, solid
complex or hydrate such as sodium p-toluene -sulfo-chloramine-trihydrate (choramine-T),
sodium benzene-sulfo-chloramine-dihydrate, calcium hypochlorite tetrahydrate, or chlorinated
trisodium phosphate containing 0.5 to 4% available chlorine produced by combining
trisodium phosphate in its normal Na₃PO₄: 12H₂0 form and an alkali metal hypochlorlte
(e.g., sodium hypochlorite).
[0059] In compositions in which the alkali and alkaline earth metal hypochlorites are used
as the chlorine source, these compounds can be used in the form of anhydrous dispersed
solids in order to prevent deteriation of the nonionic surfactants in the composition.
[0060] The preferred sources of hypochlorite are dichloro- and trichloroisocyanurates and
chloramine-T (p-Toluenesulfochloramine).
[0061] Typically the chlorine-liberating agents are employed in a proportion of about 1
to 18% by weight of the composition, and preferably about 1.0 to 15% and more preferably
2 to 12%. Desirably the proportion thereof employed will be such as to yield a product
which contains from about 0.5% to about 10% available chlorine on a total weight basis,
preferably 1 to 8.4% and more preferably 1 to 6.7% available chlorine.
[0062] The composition should contain sufficient chlorine bleach compound to provide about
0.5 to 10.0% by weight of available chlorine, as determined, for example, by acidification
of the composition with sulfuric acid and iodometric titration with sodium thiosulfate
monitored by a potentiometer. A composition containing about 0.9 to 18% by weight
of sodium dichloroisocyanurate dihydrate contains or provides about 0.5 to 10% available
chlorine. A composition containing about 1.6 to 10.72% by weight calcium hypochlorite
contains about 1 to 6.7% by weight available chlorine. A composition containing about
1.8 to 12.0% by weight sodium dichloroisocyanurate dihydrate contains about 1 to 6.7%
by weight of available chlorine and is especially preferred.
Bromide Compounds
[0063] The bromide source or compound used in the present invention can be a solid water
soluble bromide which preferably is of substantially neutral or slightly alkaline
nature, providing a ready source of bromide ions on dissolution in water. It is preferred
to employ alkali metal bromides such as sodium bromide, sodium bromide dihydrate,
lithium bromide, and potassium bromide, although alkaline earth metal bromides such
as calcium bromide and magnesium bromide may be employed in those instances in which
these water hardness-producing cations are not objectionable.
[0064] The bromide compound for example alkali metal bromides are used in amounts of 0.1
to 6 wt.%, preferably 0.2 to 4.0 wt.% and more preferably 0.3 to 3.0 wt.%.
[0065] Preferably the bromide is employed in an amount which is substantially less than
the molar equivalent of available chlorine present in the product, e.g., the mole
ratio of water soluble bromide to available chlorine is in the range of 0.04 to 0.12,
preferably less than 0.10, for example 0.05 to 0.095, and typically 0.05 to 0.090.
[0066] A balanced detergent composition is obtained which contains a small effective amount
of the bromide to react with the hypochlorite to form a sufficient amount of hypobromite
to remove the starchy carbohydrate soil and to leave a sufficient amount of hypochlorite
ion in the wash bath to remove the proteinaceous soil.
[0067] Thus, the weight percent available chlorine and the mole ratio of bromide ion to
available chlorine ion are critical features of the present invention.
Builder Salts
[0068] Generally, liquid ADD effectiveness is directly related to (a) available chlorine
levels; (b) alkalinity; (c) solubility in washing medium; and (d) foam inhibition.
It is preferred that the pH of the aqueous wash bath after addition of the liquid
ADD composition be at least about 9.5, more preferably from about 10.5 to 13.5 and
most preferably at least about 11.5.
[0069] The amount of alkali metal sillcate added and the amount of alkali metal TPP added
can be used to obtain the desired alkalinity in the wash bath. The sodium carbonate
can be added to act as a buffer to maintain the desired pH level. The sodium carbonate
can be added in an amount of 0 to 25 wt.%, preferably 5 to 20 wt.% and typically about
5 to 15 wt.% of the detergent composition.
[0070] The compositions of the present invention can contain inorganic builder salts such
as NaTPP or organic builder salts such as the alkali metal salts of polycarboxylic
acids.
[0071] A preferred inorganic builder salt is an alkali metal polyphosphate such as sodium
tripolyphosphate (TPP). In place of all or part of the alkall metal polyphosphate
one or more other detergent builder salts can be used. Suitable other builder salts
are alkali metal borates, phosphates and bicarbonates. Specific examples of such builders
are sodium tetraborate, sodium pyrophosphate, potassium pyrophosphate, sodium bicarbonate,
sodium hexametaphosphate, sodium sesquicarbonate, sodium mono and diorthophosphate,
potassium bicarbonate and sodium or potassium ziolites.
[0072] The detergent builders, e.g. NaTPP may be employed in the nonaqueous liquid ADD composition
in a range of 20 to 60%, preferably about 15 to 55 wt.%, and more preferably about
20 to 45 wt.%, and should preferably be free of heavy metal which tends to decompose
or inactivate the chlorine bleach compounds. The NaTPP may be anhydrous or hydrated,
including the stable hexahydrate with a degree of hydration of 6 corresponding to
about 18% by weight of water or more.
[0073] The NaTPP may be replaced in whole or in part by organic builder salts. Since the
compositions of this invention are generally highly concentrated, and, therefore,
may be used at relatively low dosages, it is desirable to supplement any phosphate
builder (such as sodium tripolyphosphate) with an auxiliary builder such as an alkali
metal polycarboxylic acid. Suitable alkali metal polycarboxylic acids are alkali metal
salts of citric and tartaric acid, e.g. monosodium and disodium citrate (anhydrous).
The sodium salts of citric and tartaric acids are preferred.
Foam Inhibitors
[0074] Foam inhibition is important to increase dishwasher machine efficiency and minimize
destabilizing effects which might occur due to the presence of excess foam within
the washer during use. Foam may be sufficiently reduced by suitable selection of the
type and/or amount of detergent active material, the main foam-producing component.
The degree of foam is also somewhat dependent on the hardness of the wash water in
the machine whereby suitable adjustment of the proportions of NaTPP which has a water
softening effect may aid in providing the desired degree of foam inhibition. However,
it is generally preferred to include a chlorine bleach stable foam depressant or inhibitor.
Particularly effective are the alkyl phosphonic acid esters of the formula
available, for example, from BASF-Wyandotte (PCUK-PAE), and especially the alkyl
acid phosphate esters of the formula
available, for example, from Hooker (SAP) and Knapsack (LPKN-158), in which one or
both R groups in each type of ester may represent independently a C₁₂₋₂₀ alkyl group.
Mixtures of the two types, or any other chlorine bleach stable types, or mixtures
of mono- and di-esters of the same type, may be employed. Especially preferred is
a mixture of mono- and di-C₁₆₋₁₈ alkyl acid phosphate esters such as monostearyl/distearyl
acid phosphates 1.2/1 (Knapsack). When employed, proportions of 0.01 to 5 wt.%, preferably
0.1 to 5 wt.%, especially about 0.1 to 0.5 wt.%, of foam depressant in the composition
is typical, the weight ratio of detergent active component to foam depressant generally
ranging from about 10:1 to 1:1 and preferably about 4:1 to 1:1. Other defoamers which
may be used include, for example, the known silicones such as Dow Corning 1400 and
1500, which are polysiloxanes mixed with dispersed silica.
[0075] The alkali metal silicates, e.g. sodium silicate, which provide alkalinity and protection
of hard surfaces, such as fine china, are employed in an amount ranging from about
5 to 30 wt.%, preferably about 8 to 25 wt.%, and more preferably about 10 to 20 wt
. %, in the composition. The sodium silicate also protects the washing machine from
corrosion. The sodium silicate can have a Na₂O:SiO₂ ratio of 1.6/1 to 1/3.2. The sodium
silicate can be added in the form of nonaqueous dispersions or dry powders, preferably
having an Na₂O:SiO₂ ratio of from 1/1 to 1/2.8, for example, 1/1 to 1/2.4. Potassium
silicates of the same ratios can also be used. The preferred alkali metal silicates
are sodium disilicate and sodium metasilicate.
[0076] Most of the other components of the composition, for example, sodium hypochlorite
and foam depressant can be added to the nonaqueous liquid composition in the form
of dry powders or nonaqueous dispersions or solutions.
[0077] Various conventional ingredients may be included in these compositions in small amounts,
generally less than about 4 wt. %, such as perfume, hydrotropic agents such as the
sodium benzene, toluene, xylene and cumene sulphonates, preservatives, dye stuffs
and pigments and the like, all of course being stable to chlorine bleach compound
and high alkalinity (properties of many of the components). Especially preferred for
coloring are the chlorinated phthalocyanines and polysulphides of aluminosilicate
which provide, respectively, pleasing green and blue tints.
[0078] The composition may also include conventional organic or inorganic thickening agents
in amounts sufficient to obtain a product consistency of a cream or a paste.
[0079] The thickening agents, i.e. thickeners or suspending agents which provide thickening
properties, are known in the art and may be organic or inorganic, water soluble or
insoluble, dispersible or colloid-forming, and monomeric or polymeric, and should
of course be stable in these compositions, e.g. stable to alkalinity and bleach compounds,
such as sodium hypochlorite. The preferred thickeners generally comprise the inorganic,
colloid-forming clays of smectite and/or attapulgite types. These materials are generally
used in amounts of about 1.5 to 10, preferably 2 to 5 wt%, to confer the desired thickening
properties to the formulation.
[0080] Smectite clays include montmorillonite (bentonite), hectorite, attapulgite, smectite,
saponite, and the like. Montmorillonite clays are preferred and are available under
tradenames such as Thixogel (Registered Trademark) No. 1 and Gelwhite (Registered
Trademark) GP, H, etc., from Georgia Kaolin Company; and ECCAGUM (Registered Trademark)
GP, H, etc., from Georgia Kaolin Company; and ECCAGUM (Registered Trademark) GP, H,
etc., from Luthern Clay Products. Attapulgite clays include the materials commercially
available under the tradename Attagel (Registered Trademark), i.e. Attagel 40, Attagel
50 and Attagel 150 from Engelhard Minerals and Chemicals Corporation. Mixtures of
smectite and attapulgite types in weight ratios of 4:1 to 1:5 are also useful. Thickening
or suspending agents of the foregoing types are well known in the art, being described,
for example, in USP 3,985,668, which is incorporated herein by reference thereto.
[0081] The conventionally used organic polymeric thickening agents, such as the polyacrylates,
e.g. powdered polyacrylates having a molecular weight of 1,000-20,000 can be used.
Suitable polyacrylates, e.g. sodium, are Alcosperse 130D, MW 15,000, available from
Alco Chem. Co. Alcosperse 149D, MW 2000, available from Alco Chem. Co, and Alcrysol
45N, MW 4500, available from Rhom & Haas Co. The polyacrylates are disclosed more
fully in copending application Serial No. 323,126, filed March 10, 1989, which is
encorporated herein by reference thereto.
[0082] The nonaqueous liquid ADD compositions of this invention are readily employed in
known manner for washing dishes, glasses, cups, cookware, eating utensils and the
like in an automatic dishwasher, provided with a suitable detergent dispenser, in
an aqueous wash bath containing an effective amount of the composition.
[0083] In a preferred embodiment of the invention an automatic dishwashing detergent concentrate
composition is formulated using the below named ingredients.
Component |
Weight Percent |
Organic Carrier Liquid |
30-45 |
Surfactant Detergent |
3-7.0 |
Sodium Tripolyphosphate |
20-45 |
Sodium Carbonate |
5-15 |
Sodium Silicate |
10-20 |
Sodium Bromide |
1-3.0 |
Sodium Dichloroisocyanurate (Available Chlorine) |
3-6.7 |
Sodium Polyacrylate (MW 15,000) |
4-10 |
Pigment |
0.5 to 2.5 |
[0084] The commercially available liquid detergent composition dose per wash is 80 grams,
whereas the concentrate liquid detergent composition dose per wash of the present
invention is 40 grams.
[0085] The nonaqueous liquid dishwasher detergent compositions of the present invention
can contain conventional dishwashing detergent composition additives. The formulations
can be prepared with commercially available powder detergent builders, chlorine bleach
source compounds and bromide compounds.
[0086] The formulations can be prepared using the conventional blending and mixing procedures
used for the preparation of liquid detergent compositions as briefly described below.
Method Of Preparation of Liquid Composition
[0087] The compositions of the present invention can be prepared in two stages. In the first
stage powdered silicate and low molecular weight polyacrylate powder are premilled
using a ceramic ball mill. The premilled materials are then mixed using a standard
rotary mixer. This mixed material is then transferred to an attritor and milled for
30 minutes at 500 rpm using 1/4 inch stealite grinding media.
[0088] In the second stage Butylcarbitol (organic carrier liquid) and Neodol 25-6.5 (nonionic
surfactant) are mixed, and the defoamer and phosphate builder salts are added. The
premilled silicate and polyacrylate are then added to the Butylcarbitol and nonionic
surfactant mixture followed by the addition of sodium carbonate, chlorine bleach,
bromide and the remaining ingredients. After mixing the liquids solids mixture is
vigorously stirred to obtain a stable dispersion of the solids in the organic carrier
liquid.
[0089] One or more of the ingredients can be omitted or additional ingredients such as perfumes
and anti-foam agents can be added to the composition.
[0090] The term nonaqueous liquid compositions as used herein is intended to include compositions
containing 0-15% water, typically 2-12% and more typically 4-8% water. The water can
be present in the form of hydrated compounds, i.e. bound water, for example, sodium
tripolyphosphate hexahydrate, hydrated sodium carbonate, hydrated sodium sulfate and
dichloroisocyanurate dihydrate and/or in the form of moisture, i.e. unbound water.
It is preferred, however, that the composition contain less than 1% moisture as unbound
water.
[0091] In the compositions containing an alkali metal hypochlorite and a nonionic surfactant,
it is particularly important that the compositions contain less than 1% unbound water,
or substantially 0% unbound water, inorder to prevent deterioration of the nonionic
surfactant
[0092] The invention may be put into practice in various ways and a number of specific embodiments
will be described to illustrate the invention with reference to the accompanying examples.
[0093] All amounts and proportions referred to herein are percent by weight of the composition
unless otherwise indicated.
[0094] The present invention is further illustrated by the following examples.
Example 1
[0095] In accordance with the present invention nonaqueous liquid automatic dishwasher detergent
compositions are formulated using the below named ingredients in the amounts indicated.
Ingredient |
Concentrated Composition Wt.% |
Comparison Composition Wt.% |
Organic Carrier Liquid(1) |
31.14 |
34.94 |
Surfactant(2) |
6.0 |
6.0 |
Sodium Tripolyphosphate (Anhydrous) |
23.0 |
26.0 |
Sodium Meta-Silicate |
14.5 |
14.5 |
Sodium Acrylate(3) |
6.0 |
- |
Sodium Carbonate |
12.0 |
12.0 |
|
Sodium Dichloroisocyanurate(4) |
5.36 |
5.36 |
Sodium Bromide |
0.80 |
- |
Dow 1500 Antifoam(5) |
1.2 |
1.2 |
|
100 |
100 |
(1) Methoxypolyethylene Glycol, Carbowax MPEG 350, Union Carbide. |
(2) Tergital MDS-42, from Union Carbide, which is a nonionic surfactant and is a C₁₂-C₁₄
linear alcohol containing 55% by weight random distributed oxyalkyl groups of which
42% are ethoxy and 58% propoxy groups. |
(3) Alcosperse 130 D, MW 15,000. |
(4) ACl 56, from Monsanto Corporation, available chlorine in composition is 3.0% by
weight. |
(5) Mixture of silica powder and dimethyl polysiloxan. |
[0096] The mole ratio of bromide to available chlorine in the above invention composition
is about 0.09.
[0097] Multi-soil cleaning tests are run at stress conditions of 120°F wash cycle temperature
and 300 ppm hard water in a low performance dishwasher. This is done to show differences
between the products which are less apparent in normal use conditions with tap water,
e.g. 100 ppm hard water, and 140°F wash temperature.
[0098] Egg soil is prepared by mixing egg yolk with an equal amount of 2.5N calcium chloride
solution. 0.4 grams of this mixture is applied to the usable surface of 7.5 inch china
plates in a thin film. The plates are aged in 50% relative humidity overnight.
[0099] Oatmeal soil is prepared by boiling 24 grams of Quaker Oates in 400 ml of tap water
for ten minutes. 3 grams of this mixture is spread onto a 7.5 inch china plate. The
plates are aged for 2 hours at 80°C. They are then stored overnight at room temperature.
Two plates are used per wash. The plates are always placed in the same position in
the dishwasher. The nonaqueous liquid detergent products to be tested are added at
the beginning of the wash cycle. 40 gm of product is used for each test. All plates
are scored by measuring the percent area cleaned.
[0100] The multi-soil cleaning results are reported below:
|
Percent Soil Removal |
Product |
Egg |
Starch |
Invention Composition |
50% |
90% |
Comparison Composition |
45% |
40% |
[0101] The above compositions are also tested cleaning glass tumblers.
[0102] The ASTM Method D3556-79 for the deposition on glassware during mechanical dishwashing
is used to evaluate the buildup of spots and film on glassware. 40 gm of comparison
liquid ADD and 40 gm of the invention liquid detergent is used in each test. All testing
reported is done in Kenmore Model 587.1548580 and/or model 587.1546580 Automatic Dishwasher.
The water wash temperature is 120°F and the water has 300 ppm hardness and the results
are the average of four washes using 6 to 10 glass tumblers per wash.
[0103] The information obtained is reported below.
[0104] The film/spot scale used in the above evaluation is given below.
SPOT/FILM SCALE
Spot On Glasses
[0105]
1 = no spots
2 = 1-2 spots
3 = 25 percent of glass covered with spots
4 = 50 percent of glass covered with spots
5 = 100 percent of glass covered with spots
Film On Glasses
[0106]
1 = best - no film
2 = film slightly apparent
3 = increase in noticeable film
4 = filming significant
5 = filming becoming excessive
6 = filming highly excessive
Example 2
[0107] Following the teachings of the invention a nonaqueous liquid automatic dishwasher
detergent composition is formulated using the below named ingredients in the amounts
indicated.
|
Weight Percent |
Organic Carrier Liquid(1) |
32-38 |
Sodium Tripolyphosphate(2) |
23.4 |
Nonionic Surfactant(3) |
3.0 |
Sodium Carbonate |
12 |
Sodium Silicate |
14.0 |
Sodium Acrylate(4) |
6.0 |
Sodium Bromide(5) |
0-6 |
|
Sodium Dichloroisocyanurate(6) |
3.6 |
(1) Butylcarbitol. |
(2) STPP (anhydrous). |
(3) Tergitol MDS-42. |
(4) Alcosperse 130 D, MW 15,000. |
(5) Sodium bromide concentration is varied from 0 (control) to 6.0 wt.% for comparison
purposes. The organic carrier liquid is adjusted to 100%. There are four formulations
prepared containing 0 (control), 0.6, 1.0 and 2.0 wt.% sodium bromide. |
(6) Available chlorine in composition is 2.0% by weight. |
[0108] The formulations and soiled dishware are prepared following the procedure of Example
1 except that porridge is substituted for the oatmeal. 40 gm of product is used for
each test. The multi-soil cleaning test is carried out following the procedure of
Example 1, but using GE Model GSD 1200G Automatic Dishwasher at 120°F wash temperature
and tap water with about 110 ppm water hardness.
[0109] The results that are obtained are reported in the below table.
Test |
ADD Formulation Sodium Bromide Concentration Weight % |
Percent Porridge Removal |
Percent Egg Removal |
Mole Ratio Bromide To Available Chlorine |
A |
0 |
20 |
90 |
- |
B |
0.6 |
80 |
75 |
0.10 |
C |
1.0 |
100 |
60 |
0.17 |
D |
2.0 |
100 |
30 |
0.34 |
[0110] The above information illustrates the effect on the removal of proteineous soil and
starch carbohydrate soil by varying the mole ratio of bromide to available chlorine
in the formulation.
Example 3
[0111] In accordance with the present invention a nonaqueous liquid automatic dishwasher
detergent composition is formulated using the below named ingredients in the amounts
indicated.
Component |
Weight Percent |
Organic Carrier Liquid |
40.2 |
Nonionic Surfactant |
3.0 |
Sodium Tripolyphosphate |
30.0 |
Sodium Carbonate |
8.0 |
Sodium Silicate (1:1) |
14.0 |
Sodium Bromide |
0.30 |
|
Sodium Dichloroisocyanurate(1) |
2.5 |
Clay Thickening Agent |
2.0 |
|
100.0 |
(1) 1.4% by weight available chlorine. |
[0112] The mole ratio of bromide to available chlorine is 0.07.
[0113] About 60 gm of the above formulation is used in an automatic dishwasher machine to
clean dishes containing baked on proteinaceous egg soil and baked on starchy carbohydrate
pasta soil.
[0114] The dishes after a normal wash cycle are removed from the dishwasher and are found
to be substantially reduced in both the proteinaceous egg soil and the starchy carbohydrate
pasta soil.
Example 4
[0115] Following the teachings of the present invention a nonaqueous liquid automatic dishwasher
detergent composition is formulated using the below named ingredients in the amounts
indicated.
Ingredient |
Weight Percent |
Organic Carrier Liquid |
36.4 |
Nonionic Surfactant |
4.0 |
Sodium Tripolyphosphate |
15.0 |
Sodium Citrate |
15.0 |
Sodium Carbonate |
8.0 |
Sodium Silicate (1:2.4) |
16 |
Sodium Bromide |
0.60 |
|
Sodium Dichloroisocyanurate(1) |
5.0 |
|
100.00 |
(1) 2.8% by weight available chlorine. |
[0116] The mole ratio of bromide to available chlorine is 0.07.
[0117] About 60 gm of the above concentrated liquid formulation is used in an automatic
dishwasher machine to clean dishes containing baked on proteinaceous egg soil and
baked on starchy carbohydrate pasta soil.
[0118] The dishes after a normal wash cycle are removed from the dishwasher and are found
to be substantially reduced in both the proteinaceous egg soil and the starchy carbohydrate
pasta soil.
[0119] The above illustrative Examples show that the dual bleach automatic dishwashing powder
detergent compositions of the present invention provide improved removal of proteinaceous
soils and starchy carbohydrate soils from dishware, glassware and the like.
[0120] The invention is not to be limited by the above disclosure and examples which are
given as illustrations only. The invention is to be interpreted in accordance with
the below claims.