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(11) | EP 0 021 545 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Abrasive-containing liquid detergent compositions and non-clogging dispensing package therefor |
| (57) Abrasive liquid detergent compositions containing an anionic surfactant, a nonionic
surfactant and water-insoluble abrasive are disclosed. The combination of these compositions
with a package comprising a flexible container and a clog-resistant closure (1) characterized
by a domed shape and external sealing means (3) is also disclosed. |
Background
[0001] The invention relates to liquid detergent compositions containing specified amounts and types of insoluble abrasives which are especially useful in the washing of dishes. The compositions contain high-sudsing surfactants and may also contain detergency builders which complement the action of the abrasive.
[0002] The invention also relates to the combination of such liquid detergents and a package which provides convenient dispensing of the detergent composition without clogging.
[0003] The use of abrasives in powdered scouring cleansers is well known. Scouring cleansers generally contain a relatively high level of abrasive. When such scouring cleansers are used as adjuncts in the dishwashing process such products provide abracing power to make the removal of cooked, burnt or dried-on foods on kitchenware easier and more convenient. Recently, liquid scouring cleansers containing water-insoluble abrasives have become available. Such liquid compositions are disclosed in U.S. Patents 3,149,078; 3,210,285; 3,210,286; 3,214,380; 3,579,456; 3,623,990; 3,677,954; 3,813,349; 3,966,432; and 4,129,527; and British Patents 1,384,244 and 1,534,680. The use of scouring cleansers, however, is normally in addition to a specific dishwashing product, one product being required for removal of non-sticking soils, especially fats and oils, and a second product being required for scouring purposes. Canadian, Patent 1,048,365 discloses granular detergent compositions suitable for dishwashing containing 20% to 35% surfactant and 5% to 20% of abrasive material having a particle diameter in the range of 200 to 850 microns.
[0004] It is an object of the present invention to provide liquid detergent compositions containing a surfactant and an abrasive, the detergent composition being highly effective in removing food soils from kitchenware when used undiluted or in the form of a relatively concentrated water slurry, but which is highly acceptable for hand dishwashing in the dilute water solutions typically used with liguid dishwashing products.
[0005] It is a further object of the present invention to provide liquid detergent compositions containing a surfactant and an abrasive in a non-clogging dispensing package, the detergent composition being highly effective in removing food soils from kitchenware when used undiluted or in the form of a relatively concentrated water slurry, but which in a preferred embodiment is acceptable for hand dishwashing in the dilute water solutions typically used with liquid dishwashing products. It is a further object to provide a package suitable for such a product.
Summary of the Invention
[0006] The present invention comprises a liquid detergent composition containing by weight:
a) from about 15% to about 50% of an anionic surfactant;
b) from about 2% to about 15% of a suds stabilizing nonionic surfactant selected from the group consisting of amine oxides, amides, and the ethylene oxide condensates of alcohols and alkyl phenols;
c) from about 1% to about 20% of a water-insoluble abrasive having a particle diameter of from about 15 to about 150 microns and a hardness on the Mohs scale of from about 2 to about 7; and
(d) from about 20% to about 82% water; said composition providing an initial suds cover to a dishwashing solution and a suds cover after the washing of eight plates when used at a concentration of 0.07% in two gallons of 115°F water containing 7 grains/ gallons water hardness measured as CaCO3, each plate carrying 4.0 ml. of triglyceride-containing soil.
[0007] The essential package characteristics are:
a) a flexible plastic container adapated to provide an increase in internal pressure by application of compressive forces to one or more external surface areas, and
b) a clog resistant dispensing closure adapted to be mounted on said flexible plastic container, said closure consisting of a body portion and a bail-like sealing member, the body portion consisting of an annular skirt for surrounding said container finish, means for attaching said skirt to said container finish and a domed nozzle section with a central aperture, said aperture having an horizontal cross sectional area from about 0.002 square inches to about 0.025 square inches, preferably from about 0.005 square inches to about .015 square inches, a minimum diameter of about 0.05 inches preferably 0.08 inches, and a length of no more than about 0.25 inches, said bail-like sealing member having an arcuate conformation and a rotatable joint to said body section at each end, said sealing member having a gripping portion centrally located and a downwardly-projecting protrusion on its underside adapted to plug the outside of said aperture when the sealing member is in a closed position.
Detailed Description of the Invention
[0008] The detergent compositions of the present invention contain three essential components:
a) a surfactant
b) a water-insoluble abrasive
c) water.
[0009] Optional ingredients can be added to provide various performance and aesthetic characteristics.
Surfactant
[0010] The compositions of this invention contain from about 15% to about 50% of an anionic surfactant or mixtures thereof. Preferred compositions for use as a complete dishwashing product contain from about 15% to about 40% of surfactant by weight of the composition. Especially preferred are compositions containing from 20% to 35% of anionic surfactant or mixtures thereof.
[0011] Many anionic detergents can be broadly described as the water-soluble salts, particularly the alkali metal, alkaline earth metal, ammonium and amine salts, of organic sulfuric reaction products having in their molecular structure an alkyl radical containing from about 8 to about 22 carbon atoms and a radical selected from the group consisting of sulfonic acid and sulfuric acid ester radicals. Included in the term alkyl is the alkyl portion of high acyl radicals. Examples of the anionic synthetic detergents which can form the surfactant component of the compositions of the present invention are the sodium, ammonium or potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C8-C18 carbon atoms) sodium or potassium alkyl benzene or toluene sulfonates, in which the alkyl group contains from about 9 to about 15 carbon atoms, (the alkyl radical can be a straight or branched aliphatic chain); sodium or potassium paraffin sulfonates and olefin sulfonates in which the alkyl or alkenyl group contains from - about 10 to about 20 carbon atoms; sodium alkyl glyceryl ether sulfonates, especially those ethers of the higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfates and sulfonates; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfates with about 1 to about 30 units of ethylene oxide per molecule and in which the alkyl radicals contain from to about 12 carbon atoms; the reaction products of fatty acids esterified with isethionic acid and neutralized with sodium hydroxide where, for example, the fatty acids are derived from coconut oil; sodium or potassium salts of fatty acid amides of a methyl tauride in which the fatty acids, for example, are derived from coconut oil and sodium or potassium beta-acetoxy- or beta-acetamido-alkanesulfonates where the alkane has from 8 to 22 carbon atoms.
[0012] Specific examples of alkyl sulfate salts which can be employed in the instant detergent compositions include sodium lauryl alkyl sulfate, sodium stearyl alkyl sulfate, sodium palmityl alkyl sulfate, sodium decyl sulfate, sodium myristyl alkyl sulfate, potassium lauryl alkyl sulfate, potassium stearyl alkyl-sulfate, potassium decyl sulfate, potassium palmityl alkyl sulfate, potassium myristyl alkyl sulfate, sodium dodecyl sulfate, potassium dodecyl sulfate, potassium tallow alkyl sulfate, sodium tallow alkyl sulfate, sodium coconut alkyl sulfate, potassium coconut alkyl sulfate and mixtures of these surfactants. Highly preferred alkyl sulfates are sodium coconut alkyl sulfate, potassium coconut alkyl sulfate, potassium lauryl alkyl sulfate and sodium lauryl alkyl sulfate.
[0013] Suitable alkylbenzene or alkyltoluene sulfonates include the alkali metal (lithium, sodium, potassium), alkaline earth (calcium, magnesium) and alkanolamine salts of straight-or branched-chain alkylbenzene or alkyltoluene sulfonic acids_ Alkylbenzene sulfonic acids useful as precursors for these surfactants include decyl benzene sulfonic acid, undecyl benzene sulfonic acid, dodecyl benzene sulfonic acid, tridecyl benzene sulfonic acid, tetrapropylene benzene sulfonic acid. Preierred sulfonic acids as precursors of the alkyl-benzene sulfonates useful for compositions herein are those in which the alkyl chain is linear and averages about 12 carbon atoms in length. Examples of commercially available alkyl benzene sulfonic acids useful in the present invention include Conoco SA 515 and SA 597 marketed by the Continental Oil Company and Calsoft LAS 99 marketed by the Pilot Chemical Company.
[0014] Particularly preferred anionic surfactants useful herein arc alkyl ether sulfates having the formula RO(C2H4O)xSO3M wherein R is alkyl or alkenyl of about 10 Lo about 20 carbon atoms, x is 1 to 30, and M is a water-soluble cation. The alkyl ether sulfates useful in the present invention are condensation products of ethylene oxide and monohydric alcohols having from about 10 to about 20 carbon atoms. Preferably, R has 12 to 18 carton atoms. The alcohols can be derived from natural fats, e.g., coconut oil or tallow, or can be synthetic. Such alcohols are reacted with 1 to 30, and especially 1 to 12, molar proportions of ethylene oxide and the resulting mixture of molecular species is sulfated and neutralized.
[0015] Specific examples of alkyl ether sulfates of the present invention are sodium coconut alkyl triethylene glycol ether sulfate, magnesium tallow alkyl triethylene glycol ether sulfate, and sodium tallow alkyl hexaoxy ethylene sulfate. Preferred alkyl ether sulfates are those comprising a mixture of individual compounds, said mixture having an average alkyl chain length of from about 12 to 16 carbon atoms and an average degree of ethoxylation of from about 1 to 12 moles of ethylene oxide.
[0016] Additional examples of anionic surfactants useful herein are the compounds which contain two anionic functional groups. These are referred to as di-anionic surfactants. Suitable dianionic surfactants are the disul- fonates, disulfates, or mixtures thereof which may be represented by the following formula:
where R is an acyclic aliphatic hydrocarbyl group naving is to 20 carbon atoms and M is a water-solubilizing cation, for example, the C15 to C20 disodium 1,2-alkyldisulfates, C15 to C20 dipotassium-1,2-alkyldisulfonates or disulfates, disodium 1,9-hexadecyl disulfates, C15 to C20 disodium 1,2-alkyldisulfonates, disodium 1,9-stearyldisulfates and 6,10-octadecyldisulfates.
Nonionic Surfactant
[0017] The compositions of this invention contain from about 2% to about 15%, preferably from about 3% to about 8%, most preferably 4%, of a suds stabilizing nonionic surfactant or mixtures thereof. The presence of this component is essential to satisfactory performance and acceptance as a complete dishwashing product. In preferred embodiments the nonionic surfactants will be in a weight ratio to the anionic surfactants of from about 1:10 to about 1:2, most preferably from about 1:7 to about 1:3.
[0018] Monionic surface active agents operable in the instant compositions can be any of three basic types -- the alkylene oxide condensates, the amides and the semi-polar nonionics.
[0019] The alkylene oxide condensates are broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which can be aliphatic or alkyl aromatic in - nature. The length of the hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.
[0020] Examples of such alkylene oxide condensates include:
(1) The condensation products of aliphatic alcohols with ethylene oxide. The alkyl chain of the aliphatic alcohol can either be straight or branched and generally contains from about 8 to about 22 carbon atoms. Examples of such ethoxylated alcohols include the condensation product of about 6 moles of ethylene oxide with 1 mole of tridecanol, myristyl alcohol condensed with about 10 moles of ethylene oxide per mole of myristyl alcohol, the condensation product of ethylene oxide with coconut fatty alcohol wherein the coconut alcohol is a mixture of fatty alcohols with alkyl chains varying from 10 to 14 carbon atoms and wherein the condensate contains about 6 moles of ethylene - oxide per mole of alcohol, and the condensation product of about 9 moles of ethylene oxide with the above-described coconut alcohol. An example of a commercially available nonionic surfactant of this type includes Neodol 23-6.5 marketed by the Shell Chemical Company.
(2) The polyethylene oxide condensates of alkyl phenols. These compounds include the condensation products of alkyl phenols having an alkyl group containing from about 6 to 12 carbon atoms in either a straight chain or branched chain configuration, with ethylene oxide, the said ethylene oxide being present in amounts equal to 5 to 25 moles of ethylene oxide per mole of alkyl phenol. The alkyl substituent in such compounds can be derived, for example, from polymerized propylene, diisobutylene, octene, or nonene. Examples of compounds of this type include nonyl phenol condensed with about 9.5 moles of ethylene oxide per mole of nonyl phenol, dodecyl phenol condensed with about 12 moles of ethylene oxide per mole of phenol, dinonyl phenol condensed with about 15 moles of ethylene oxide per mole of phenol, di-isooctylphenol condensed with about 15 moles of ethylene oxide per mole of phenol. Commercially available nonionic surfactants of this type include Igepal CO-610 marketed by the GAF Corporation; and Triton X-45, X-114, X-100 and X-102, all marketed by the Rohm and Haas Company.
(3) The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol. The hydrophobic portion of these compounds has a molecular weight of from about 1500 to 1800 and of course exhibits water insolubility. The addition of polyoxyethylene moieties to this hydrophobic portion tends to increase the water-solubility of the molecule as a whole, and the liquid character of the product is retained up to the point where the polyoxyethylene content is about 500 of the total weight of the condensation product. Examples of compounds of this type include certain of the commercially available Pluronic surfactants marketed by the Wyandotte Chemicals Corporation.
(4) The condensation products of ethylene oxide with the product resulting form the reaction of propylene oxide and ethylene diamine. The hydrophobic base of these products consists of the reaction product of ethylene diamine and excess propylene oxide, said base having a molecular weight of from about 2500 to about 3000- This base is condensed with ethylene oxide to the extent that the condensation product contains from about 40% to about 80% bv weight of polyoxyethylene and has a molecular weight of from about 5,000 to about 11,000. Examples of this type of nonionie surfactant include certain of the commercially available Tetronic compounds marketed by the Wyandotte Chemicals Corporation.
[0021] Examples of the amide type of nonionic surface active agent include the ammonia, monoethanol and diethanol amides of fatty acids having an acyl moiety of from about 8 to about 18 carbon atoms. These acyl moieties are normally derived from naturally occurring glycerides, e.g., coconut oil, palm oil, soybean oil and tallow, but can be derived synthetically, e.g., by the oxidation of petroleum, or by hydrogenation of carbon monoxide by the Fischer-Tropsch process.
[0022] Examples of the semi-polar type of nonionic surface active agents are the amine oxides, phosphine oxides and sulfoxides. These materials are described more fully in Berry, U.S. Patent 3,819,528, issued June 25, 1974, incorporated herein by reference. Particularly preferred are amine oxides of the formula:
wherein R1 is a C10-18 alkyl and R2 and R3 are methyl or ethyl.
[0023] The level and type of surfactant used in the compositions of this invention provide an initial suds cover to a dishwashing solution and a suds cover after the washing of 8 plates when used at a concentration of 0.07% in 2 gallons of 115°F. water containing 7 grains/ gallon water hardness measured as CaCO3, each plate carrying 4.0 ml of a triglyceride containing soil. Suds are generated by mechanical agitation and the suds cover and height measured. A dinner plate carrying the soil is washed successively with the introduction of 4.0 ml of soil each time. An essentially complete suds cover of the washing solution is more important than suds height, but, preferably, the suds cover after the washing of 8 plates is at least about 1/2 inch in height.
[0024] The sudsing characteristic of the preferred high-sudsing compositions of the invention is that necessary to provide the user of the product with an indication of cleaning potential in a dishwashing solution. Soils encountered in dishwashing act as suds depressants and the presence or absence of suds from the surface of a dishwashing solution is a convenient guide to product usage. Mixtures of anionic surfactants and nonionic surfactants, especially amides and amine oxide nonionic surfactants, are utilized in the compositions of the invention because ot their high sudsing characteristics, their suds stability in the presence of food soils and their ability to indicate accurately an adequate level of product usage in the presence of soil.
Optional Surfactants
[0025] The compositions of the invention may contain optional surfactants other than anionic and nonionic surfactants such as ampholytic, zwitterionic and cationic surfactants.
[0026] Ampholytic surfactants can be broadly described as derivatives of aliphatic amines which contain a long chain of about 8 to 18 carbon atoms and an anionic water-solubilizing group, e.g. carboxy, sulfo or sulfate. Examples of compounds falling within this definition are sodium-3-dodecylamino propane sulfonate, and dodecyl dimethylamonium hexanoate.
[0027] Zwitterionic surface active agents operable in the instant composition are broadly described as internally- neutralized derivatives of aliphatic quaternary ammoniu, and phosphonium and tertiary sulfonium compounds in which the aliphatic radical can be straight chain or branched, and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and one contains an anionic water solubilizing group, e.g., carboxy, sulfo, sulfato, phos- phato, or phosphono.
[0028] Cationic surfactants such as quaternary ammonium compounds can find optional use in the practice of the invention to the extent they are compatible with the other surfactants in the particular composition.
ABRASIVE
[0029] The abrasive agent can be any of the water-insoluble abrasive materials known in the art which have a particle diameter of from about 15 to about 150, preferably from about 35 to about 125, microns and a hardness on the Mohs scale of from about 2 to about 7. Included are materials such as agate, mica, calcite, garnet, quartz, kieselguhr, silica, marble, tripoli, flint, feldspar, emery, pumice, alumina, perlite, expanded perlite, volcanic ash, diatomaceous earth, bentonite, amorphous silica from dehydrated silica gels, precipitated silica, plastics such as polystyrene and polyacrylates, and natural and synthetic aluminosilicates and mixtures thereof.
[0030] The amount of abrasive included in the compositions is in the range of from about 1% to about 20% of the total composition by weight. Preferred compositions contain from about 5% to about 10% by weight of abrasive.
OPTIONAL DETERGENCY BUILDER
[0031] The compositions of this invention can contain up to about 20%, preferably from about 5% to about 15%, by weight of detergency builders either of the organic or inorganic types. Examples of water-soluble inorganic builders which can be used, alone or in admixture with themselves and organic alkaline seguestrant builder salts, are alkali metal carbonates, polyphosphates, and silicates. Specific examples of such salts are sodium tripolyphosphate, sodium . carbonate, potassium carbonate, sodium pyrophosphate, potassium pyrophosphate, potassium tripolyphosphate, and sodium hexametaphosphate. Examples of organic builder salts which can be used alone, or in admixture with each other or with the preceding inorganic alkaline builder salts, are alkali metal polycarboxylates, e.g., water-soluble citrates such as sodium and potassium citrate, sodium and potassium tartrate, sodium and potassium ethylenediaminetetraacetate, sodium and potassium N-(2-hydroxyethyl)-ethylene diamine triacetates, sodium and potassium nitrilotriacetates (NTA) and sodium and potassium N-(2-hydroxyethyl)-nitrilo diacetates. Other organic builder salts include the alkali metal salts of phytic acid, e.g., sodium phytate (see U.S. Patent 2, 739, 942). Water-soluble salts of ethane-1-hydroxy-1,1- liphosphonate (EHDP) are also suitable. Mixtures of any of the preceding water-soluble organic or inorganic builder salts can be used.
[0032] The compositions of this invention can contain insolu- ole builder salts selected from certain zeolites or alumi- nosilicates. One such aluminosilicate which is useful in the compositions of the invention is water-insoluble crystalline aluminosilicate ion exchange material of the formula:
wherein Z and y are at least 6, the molar ratio of Z to y is from 1.0 to 0.5 and x is from 10 to 264, said material having a particle size diameter of from about 0.1 micron to about 10 microns, a calcium ion exchange capacity of at least about 200 mg. CaCO3eq./gram and a calcium ion exchange rate of at least about 2 grains Ca++ /gallon/ minute/gram. This ion exchange builder is more fully described in Belgian Patent 814,874 issued on November 12, 1974 to Corkill et al, herein incorporated by reference. A preferred aluminosilicate of this type is Zeolite A.
[0033] A second water-insoluble aluminosilicate ion exchange material useful herein is water-insoluble amorphous hydrated aluminosilicate material of the eemperical formula:
wherein M is sodium, potassium, ammonium, or substituted ammonium, Z is from about 0.5 to about 2, y is -1 and said material having a particle size diameter of less than 100, preferably less than 10, microns, a magnesium ion exchance capacity of at least about 50 milligrams equivalent of CaCO3 hardness per gram of anhydrous aluminosilicate and a Mg++ exchange rate of at least about 1 grain/gallon/minute/ gram/gallon; and mixtures thereof. This ion exchange builder is more fully described in Gedge et al's French Patent 2,237,839 published February 14, 1975, herein incorporated by reference.
Water
[0034] The compositions of this invention contain from about 20% to about 82%, preferably from about 40% to about 75%, water.
Optional Ingredients
[0035] Alcohols, such as ethyl alcohol, and hydrotropes, such as sodium and potassium toluene sulfonate, sodium and potassium xylene sulfonate, trisodium sulfosuccinate and related compounds (as disclosed in U.S. Patent 3,915,903, incorporated herein by reference) and urea, can be utilized in the interests of achieving a desired product phase stability, viscosity, and yield value. Also useful in the compositions of this invention are suspending or thickening agents such as those disclosed in U.S. Patent 3,393,153 incorporated herein by reference including colloidal silica having a mean particle diameter ranging from about 0.01 micron to about 0.05 micron colloidal clays such as bentonites or chemically treated bentonites, isomorphous silicates, especially those with a high magnesium content, and particulate polymers such as polystyrene, oxidized polystyrene having an acid number of from 20 to about 40, sulfonate polystyrene having an acid number of from about 10 to about 30, polyethylene, oxidized polyethylene having an acid number of from about 10 to about 30; sulfonated polyethylene having an acid number of from about 5 to about 25; polypropylene, oxidized polypropylene having an acid number of from about 10 to about 30 and sulfonated polypropylene having an acid number of from about 5 to about 25, all of said particulate polymers having mean particle diameters ranging from about 0.01 micron to about 30 mmicorns. Other examples of suspending and thickening agents include copolymers of styrene with monomers such as maleic anhydride, nitrilonitrile, methacrylic acid and lower alkyl esters of methacrylic acid, copolymers of styrene with methyl or ethyl acrylate, methyl or ethyl malcate, vinyl acetate, acrylic, maleic or fumaric acids and mixtures thereof. The mole ratio of ester and/or acid to styrene is preferably in the range from about 4 to about 40 styrene units per ester and/or acid unit. Such materials preferably have a mean particle diameter range of from about 0.05 micron to about 1 micron and molecular weights ranging from about 500,000 to about 2,000,000. Cellulosic polymers such as carboxymethyl cellulose and hydroxypropyl cellulose and gums such as guar gum and gum tragacanth are also suitable suspending and thickening agents.
[0036] The detergent compositions of this invention can contain, if desired, any of the usual adjuvants, diluents and additives, for example, perfumes, enzymes, dyes, antitarnishing agents, antimicrobial agents, and the like, without detracting from the advantageous properties of the compositions- Alkalinity sources and pH buffering agents such as alkali metal carbonates and bicarbonates, monoethanolamine, triethanolamine, alkali metal hydroxides, etc., can also be utilized. A preferred pH range for a 1% solution in water is from about 6 to about 11.
Physical Characteristics of the Detergent Composition
[0037] The liquid detergent compositions of the invention contain abrasives as suspended solids and may contain other solid or liquid ingredients that provide desired product stability characteristics and that affect product viscosity. In general, the products of the invention are thixotropic or pseudoplastic and resistant to settling out of the abrasive or other solids yet sufficiently fluid for dispensing with the package of the invention. In general, the compositions have a Brookfield viscosity of from about 400 cps to about 2500 cps when measured at 50 rpm and a yield value of from about 5 to about 600 dynes per square centimeter at 25°C.
[0038] The important physical property consideration of the compositions of the invention is their yield value. The consistency of simple (or Newtonian) liquids is a function of the nature of the material, temperature, and pressure only. This consistency is known as the "fluid viscosity coefficient," "absolute viscosity," or merely "viscosity," and is usually measured in ccntipoises (1 centipoise = 0.01 gram/centimeter-second). With a Newtonian liquid, any force applied to the system produces some defomation, according to the formula du/dr=F/p where du/dr = the rate of shear; F = the shear stress, or shearing force per unit area; and µ = the viscosity coeeficient.
[0039] In the case of non-Newtoian liquids, on the other hand, the consistency is a function of the material, pressure, temperature, and also the shear stress applied to the system. Those non-Newtonian liquids which are classified as Bingham plastics, or real plastics, are not always deformed when a force is applied to the system. Deformation, if any, takes place according to the formula du/dr=(F∫)/µc where βα= the apparent viscosity, or plastic viscosity, at the shear stress F;∫=a characteristic of the liquid called the yield stress, or yield value, measured in units of pressure; and du/dr and F are as defined above.
[0040] If the shear stress applied to the system is less than the yield value, the system will not be deformed at all. Hence a Bingham plastic system is capable of supporting indefinitely insoluble particulate material which has a density greater than that of the supporting medium, so long as the material has such a particle size and density that the shear stress which each particle places on the supporting medium does not exceed the yield value.
[0041] This is to be contrasted with suspension of heavy insoluble particulate material in Newtonian liquids with high viscosities. In highly viscous Newtonian liquids, insoluble particulate material is suspended only because the rate of flow is slow. In Bingham plastics, insoluble particulate material is suspended because the stress imposed by the particles does not exceed the yield value of the liquid, and therefore, there is no flow at all. Of course, if the yield value of the supporting medium should sufficiently decrease for any reason, the particles would not longer be suspended. This could be caused, for example, by a physical or chemical change in the supporting medium. If one of the componennts of the supporting medium is an emulsion which settles into layers upon standing, the yield value can be lost temporarily, but in such a case, the original composition can be reconstituted by mixing. If a chemical reaction either consumes a vital component or produces a damaging one, the loss of yield value can be permanent.
[0042] Because it is usually not known whether a system behaves in a truly plastic manner at low shear rates, the measurement of exact yield values is estimated, in dynes per square centimeter, by the following relationship:
This relationship represents an extrapolation of the sheer curve to 0 r.p.m. since an absolute shear stress cannot be measured at 0 r.p.m.
[0043] The yield value of the liquid detergent compositions of this invention ranges from about 5 to about 600 dynes per square centimeter. If the yield value is too low, the insoluble, particulate material will not be suspended, because the weight of the individual particles, distributed over the area which supports the particles, will exceed the yield value. However, if the yield value is too great, the composition will become thick and unmanageable because as the yield value increases, so will the apparent viscosity.
[0044] A preferred range of yield values to support the insoluble particulate material used in the liquid detergent compositions of this invention is from about 100 to about 400 dynes per square centimeter.
[0045] The physical characteristics of the compositions can present a dispensing problem because of a slow "drain back" characteristic that leads to product retention and subsequent clogging in various parts of a dispensing closure. This difficulty is greatly intensified when the closure is not sealed after use and water and other solvents evaporate from the product retained in the closure.
The Clog Resistant Package
[0046] As discussed hereinbefore the essential package elements are: 1) a flexible package container to provide the squeeze dispenssing characteristics typical of a variety of consumer products including dishwashing liquids and liquid abrasive cleansers; and 2) a clog resistant closure.
[0047] Typical dishwashing liquid detergents have a viscosity within the range of from 30 cps to 300 cps, contain no suspended solids other than low levels of opacifiers and are not thixotropic or psuedoplastic to any great extent. Closure clogging is not a serious problem and directional control of dispensed product is of no particular concern.
[0048] As disclosed, for example, in U.S. Patents 3,981,421 and 4,065,037, incorporated herein by reference, the design of closures for abrasive liquid cleaning preparations involve consideration of the thixotropic nature of such products because of product retention in the closure aperture.
[0049] In the package of the present invention, the closure design is distinguished by elements particularly suited to the dispensing of the product of the invention.
[0050] The design elements of particular importance are:
1) the absence of internal mechanisms or other obstructions to product flow in the closure up to the aperture;
2) a domed nozzle portion with a horizontal inner diameter of at least about 0.2 inches;
3) an aperture through the domed nozzle portion with a horizontal cross sectional area of from about 0.002 in2 to about 0.025 in2 a minimum diameter of about 0.05 in and a length through the dome wall of no more than about 0.25 in.
[0051] The domed or hemispherical nozzle design with its absence of acute angles, i.e. "corners" does not allow any appreciable product buildup and has the beneficial effect of concentrating and focusing any compressive force applied to the flexible container in a manner to keep the nozzle region and aperture clear of product buildup. The release of pressure from the container after dispensing clears the aperture.
Brief Description of the Drawings
[0052]
Figure 1 is a top plan view of an example of the closure of the invention.
Figure 2 is a cross sectional view taken along the line 2-2 of Figure 1.
Figure 3 is a partial section, taken along the line 3-3 of Figure 1.
Description of Preferred Package Embodiments
[0053] An example of the dispensing closure of the present invention is illustrated in Figures 1 through 3 wherein like parts are identified by the same number. The closure is generally indicated at 1 having a body portion 2 and a bail-like sealing member 3. The body portion 2 has a downwardly depending annular portion or skirt 4. The inside surface of the annular portion 4 is provided with threads 5 adapted to mate and engage corresponding threads on the neck or finish of a container (not shown). Means other than threading as are well known in the art may be employed to engage the closure 1 with the neck or finish of a container within the scope of the present invention. The outside surface of the annular portion 4 can, if desired, be provided with grooves, ridges or the like both for decorative purposes and to facilitate grasping of the shell for threading it onto the container finish. The interior surface of the top portion of the body portion 2 can have a downwardly depending annual rib 6 to abut and form a seal with the top surface of the container finish.
[0054] A chimney 7 is located centrally of the top portion of the body portion 2. The chimney is generally cylindrical in configuration and is provided with an axial bore 8, open at its lower end to communicate with the interior of the container and is surmounted at its upper end with a domed or hemispherical portion 9 terminating in an aperture 10 for dispensing the product from the container and closure. The diameter of the axial bore 8 also defines the interior horizontal diameter of the domed portion which preferably is at least about 0.2 inches. The bail-like sealing member 3 has an arcuate conformation and rotatable joints 11, 12 with the top portion of the closure body portion 2. In other embodiments, the joint is located on the outside wall of the chimney by means, for example, of protuberant posts from the chimney engaging sockets on the sealing member. The sealing member 3 has a gripping portion 13 centrally located and a downwardly-projecting protrusion 14 adapted to plug the aperture 10 when the sealing member 3 is in an closed position.
[0055] The sealing member may be adapted to provide a more positive seal of the protrusion 14 with the aperture 10 during shipment than is desirable during the period of consumer use. By way of example, the posts 15, 16 can be engaged into sockets 17, 18 for shipment and sale.
[0056] Although the materials used for the dispensing package portion of the invention can be any materials that meet the stated qualifications, conventional plastic material are generally satisfactory. The container may be made of such materials as polyethylene, polypropylene or polyvinyl chloride. Particularly suitable are materials capable of formation into containers by blow molding. The parts of the closure can be made from plastic materials such as polyethylene, polystyrene, polycarbonates or polypropylene that can be formed into desired shapes by injection molding. Materials resistent to cold flow such as the polycarbonates are particularly suitable for the sealing member.
[0057] The following examples are given to illustrate the detergent compositions of the invention. All amounts and percentages are by weight unless otherwise indicated.
EXAMPLE I
[0059] All compositions listed above contain approximately 45 to 55% water and have a pH value in the range of 8.0 to 10.0.
[0060] The compositions are entirely satisfactory when used in dilute solutions as a dishwashing detergent compositions and are substantially superior to typical liquid dishwashing detergent compositions when used undiluted or in concentrated solution for removal of tightly attached soils.
[0061] Equivalent results are obtained when C12 alkyldiethanol- amide and the reaction product of a C12-15 alcohol and 8 moles of ethylene oxide are substituted for the C12 alkyl- monoethanol-amide of Composition E.
[0062] Equivalent results are obtained when sodium C12-13 alkylbenzene sulfonate and C12-15 paraffin sulfonate are substituted for the sodium C12-13 alkyl sulfate of compositions A, B, C, D and E.
[0063] Compositions A and B were stored in packages of the invention with a closure having a circular cross-section aperture with a diameter of 0.12 inches- Product was dispensed from 22 fl. oz. containers as packed and after storage of 3, 8, 10, 17 and 30 days. When the aperture was covered between uses, there was essentially no evidence of clogging to restrict or misdirect product flow when the container was subjected to a pressure of 6 lbs. applied 4 inches from the base of the container. When the aperture was left open between uses, performance was impaired but generally satisfactory. Control samples utilizing the "push-pull" liquid detergent closure of U.S. Patents 3,227,332 and 3,201,013 and the liquid abrasive cleanser closures of U.S. Patents 3,981,421 and 4,065,037 did not provide dispensing characteristics as satisfactory.
(a) from about 15% to about 50% of an anionic surfactant;
(b) from about 2% to about 15% of a suds stabilizing nonionic surfactant selected from the group consisting of amine oxides, amides and the ethylene oxide condensates of alcohols and alkyl phenols;
(c) from about 1% to about 20% of a water-insoluble abrasive having a particle diameter of from about 15 to 150 microns and a hardness on the Mohs scale of from about 2 to about 7; and
(d) from about 20% to about 82% water;
said composition providing an initial suds cover to a dishwashing solution and a suds cover after the washing of eight plates when used at a concentration of 0.07% in two gallons of 115° F. water containing 7 grains/gallon water hardness measured as CaC03, each plate carrying 4.0 ml. of triglyceride-containing soil.
(a) an abrasive containing liquid detergent composition according to Claim 1; and
(b) a clog-resistant package containing said liquid detergent composition comprising:
(i) a flexible plastic container adapted to provide an increase in internal pressure by application of a compressive force to one or more external surface areas, and
(ii) a clog-resistant dispensing closure adapted to be mounted on said flexible plastic container said closure consisting of a body portion and bail-like sealing member, the body portion consisting of an annular skirt for surrounding said container finish, means for attaching said skirt to said container finish and a domed nozzle section with a central aperture, said aperture having a horizontal cross sectional area from about 0.002 in2 to about 0.025 in2, a minimum diameter of about 0.05 in, and a length of not more than about 0.25 in., said bail-like sealing member having an urcuate conformation and a rotatable joint to said body section at each end, said sealing member having a gripping portion centrally located and a downwardly-projecting protrusion on its underside adapted to plug the outside of said aperture when the sealing member is in closed position.