EP0436971B1 - Particules de blanchiment encapsulées avec de la cire et procédé de préparation - Google Patents

Particules de blanchiment encapsulées avec de la cire et procédé de préparation Download PDF

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Publication number
EP0436971B1
EP0436971B1 EP90202882A EP90202882A EP0436971B1 EP 0436971 B1 EP0436971 B1 EP 0436971B1 EP 90202882 A EP90202882 A EP 90202882A EP 90202882 A EP90202882 A EP 90202882A EP 0436971 B1 EP0436971 B1 EP 0436971B1
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Prior art keywords
wax
bleach
particles
weight
coating
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EP0436971A3 (en
EP0436971A2 (fr
Inventor
Robert Unilever Research U.S. Inc. Gabriel
Paul Anthony Unilever Research U.S. Inc. Hanna
Ahmed A. Unilever Research U.S. Inc. Kamel
David John Unilever Research U.S. Inc. Lang
Richard Unilever Research U.S. Inc. Theiler
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Unilever PLC
Unilever NV
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Unilever PLC
Unilever NV
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    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
    • C11D3/395—Bleaching agents
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
    • C11D17/0039—Coated compositions or coated components in the compositions, (micro)capsules
    • C—CHEMISTRY; METALLURGY
    • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
    • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
    • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
    • C11D3/39—Organic or inorganic per-compounds

Definitions

  • This invention concerns paraffin wax-encapsulated bleach particles which remain stable for use in liquid and granular cleaning products, and a method for encapsulating the bleach.
  • Bleach particles have been coated with a variety of materials.
  • U.S. 3,908,045 Alterman et al.
  • bleach particles were coated with fatty acids, polyvinyl alcohol or polyethylene glycols.
  • U.S. 4,078,099, 4,126,717, and 4,136,052 (Mazzola) coated bleach particles with a mixture of 35-89% by weight of fatty acid and 1-16% by weight of microcrystalline wax, the wax having melting point of 51-99°C.
  • Other coating materials have included polymer latex, U.S. 4,759,956 (Amer et al.); polycarboxylate materials, U.S.
  • Two other methods involve dissolving the enveloping agent in an organic solvent and either spraying the resultant solution on to the particles or immersing them in the bulk solution to achieve coating. Disadvantages of these two methods are the expense of organic solvents and, more importantly, the associated environmental pollution problems.
  • U.S. 3,856,699 (Miyano et al.) describes a process of dispersing core particles under heating into a waxy material, cooling the resultant dispersion and crushing this into a powder. Thereafter, the powdered waxy material is agitated in an aqueous medium at a temperature higher than the melting point of the waxy material. Waxed core material is then passed into a non-agitated aqueous medium at a temperature lower than the melting point of the waxy material.
  • U.S. 3,856,699 (Miyano et al.) describes a process of dispersing core particles under heating into a waxy material, cooling the resultant dispersion and crushing this into a powder. Thereafter, the powdered waxy material is agitated in an aqueous medium at a temperature higher than the melting point of the waxy material. Waxed core material is then passed into a non-agitated aqueous medium at a temperature lower than the melting point of the waxy material.
  • Patent US-A-4 919 841 (Kamel et al.) teaches the steps of dispersing active material in melted wax to form an active material/wax dispersion; adding the dispersion to water containing at least one surfactant and emulsifying the active material/wax dispersion for no longer than 4 minutes therein to form capsules; cooling immediately thereafter said capsules; and retrieving the cooled capsules from the water to effect capsules of improved quality.
  • Bleach particles have also been directly sprayed with coating material in fluidized bed apparatuses, as in Brichard.
  • U.S. 3,908,045 fatty acid coating material was sprayed on to particles.
  • U.S. 3,983,254 the spray height of the spray nozzle above the fluidized bed was said to be critical.
  • U.S. 4,078,099 a rotating drum device was used to apply coating material.
  • polymeric latex was sprayed on to core materials (such as bleach) in a fluidized bed operated in a "Wurster" mode.
  • One object of the invention is to provide a single-coat wax-encapsulated bleach particle which has improved stability to degradation by ambient humidity or aqueous liquid media.
  • Another object is providing wax-encapsulated bleach particles which have a smooth, uninterrupted coating with excellent surface integrity.
  • a further object is producing such encapsulated particles by a process which avoids improper coating and the resultant problems of poor bleach stability and particle agglomeration.
  • Another object is to provide an encapsulated bleach having a coat which melts or softens sufficiently to release bleach early in most automatic dishwashing wash cycles.
  • a still further object of the invention is to provide an encapsulation process which is free of organic solvents that lead to environmental pollution problems.
  • Another object of the invention is to provide a process which operates with a minimum of processing steps.
  • Yet another object of the invention is to provide a liquid or solid cleaning composition containing the aforementioned single-coat, wax-encapsulated bleach particle, which capsule imparts stable bleach activity without leaving waxy soil after washing.
  • An even more specific object is to provide stable bleach activity to liquid dishwashing or other hard surface cleaner which also contain oxidation-sensitive components such as enzymes, perfumes, fabric softeners, structurants and surfactants.
  • the invention comprises an encapsulated bleach particle suitable for use in household cleaning products.
  • Bleach forms the core of these particles and constitutes from 45 to 65%, preferably 50-60%, by weight of the final particles (i.e., the core plus the coat).
  • a single-wax coat on the particles comprises 35-55% by weight of the particle, or preferably 40-55% by weight, or most preferably 45-55% by weight, and is selected from one or more low-melting point paraffin waxes having melting points of from 35°C to 50°C and penetration values of 10-60 mm at 25°C.
  • the single-wax coat having a thickness of from 10 to 3000, preferably from 100 to 1,000, ⁇ m thick is applied to the bleach particles.
  • the coat thickness is from 200 to 750 ⁇ m and most preferably from 300 to 600 ⁇ m.
  • the invention comprises a process for making the encapsulated bleach particles, as defined in claim 1 hereof.
  • this process comprises the steps of spraying molten paraffin wax having a low melting point, i.e. melting point of from 35°C to 50°C, on to uncoated bleach particles in a fluidized bed.
  • the bed temperature is from 20°C up to a temperature no higher than the melting point of the wax.
  • the atomization temperature of the molten wax being applied to the particles is preferably from 5 to 40°C, preferably from 5 to 10°C, greater than the melting point of the wax.
  • a single-wax coat having a thickness of 10 to 3,000 ⁇ m, preferably 100 to 1,000 ⁇ m, thick is applied to the bleach particles.
  • the rate of application of the wax coat is from 10 to 40 grams per minute per kilogram of bleach particles in the fluidized bed.
  • the fluidized bed may be operated in the top spray or Wurster spray mode. Where the top spray is used, an annealing step may advantageously follow the coating step in order to impart an uninterrupted surface and excellent surface integrity to the coat. When the fluidized bed is operated in the Wurster spray mode, no annealing step is necessary.
  • the invention comprises cleaning compositions which include 0.1 to 30% by weight of these encapsulated bleach particles.
  • the compositions may further comprise 0.01-15% surfactant, 1-75% builder, and other components. These compositions leave little or no waxy soil on surfaces they clean.
  • Figure 1 is a graph of the amount of wax coating which remains unemulsified through an automatic dishwashing cycle, as described in Example III.
  • Figure 2 is a graph of the spotting performance from autodish liquids containing bleach encapsulated with waxes of different melting points, as described in Example IV.
  • Figure 3 is a graph of chlorine released by bleach encapsulated with waxes of different melting points, as described in Example VII.
  • the encapsulated bleach particle of the invention comprises 35-55% by weight of the particle of a single coat of paraffin wax and 45-65% by weight of a core of bleach suitable for use in household cleaning compositions.
  • the paraffin wax coating comprises 40-50% by weight of the particle and the core 50-60% by weight of the particle.
  • the bleach to be encapsulated in the paraffin wax coating may be a chlorine- or bromine-releasing agent or a peroxygen compound.
  • suitable reactive chlorine- or bromine-oxidizing materials are heterocyclic N-bromo and N-chloro imides such as trichloroisocyanuric, tribromoisocyanuric, dibromoisocyanuric and dichloroisocyanuric acids, and salts thereof with water-solubilizing cations such as potassium and sodium.
  • Hydantoin compounds such as 1,3-dichloro-5,5-dimethyl-hydantoin are also quite suitable.
  • Dry, particulate, water-soluble anhydrous inorganic salts are likewise suitable for use herein such as lithium, sodium or calcium hypochlorite and hypobromite.
  • Chlorinated trisodium phosphate is another core material.
  • Chloroisocyanurates are, however, the preferred bleaching agents. Potassium dichloroisocyanurate is sold by Monsanto Company as ACL-59 ®.
  • Sodium dichloroisocyanurates are also available from Monsanto as ACL-60 ®, and in the dihydrate form, from the Olin Corporation as Clearon CDB-56 ®, available in powder form (particle diameter of less than 150 microns); medium particle size (about 50 to 400 microns); and coarse particle size (150-850 ⁇ m). Very large particles (850-1700 ⁇ m) are also found to be suitable for encapsulation.
  • Organic peroxy acids may be utilized as the bleach core.
  • the peroxyacids usable in the present invention are solid and, preferably, substantially water-insoluble compounds.
  • substantially water-insoluble is meant herein a water-solubility of less than about 1% by weight at ambient temperature.
  • peroxyacids containing at least about 7 carbon atoms are sufficiently insoluble in water for use herein.
  • Typical monoperoxy acids useful herein include alkyl peroxy acids and aryl peroxyacids such as:
  • Typical diperoxy acids useful herein include alkyl diperoxy acids and aryldiperoxy acids, such as:
  • Inorganic peroxygen-generating compounds may also be suitable as cores for the particles of the present invention.
  • examples of these materials are salts of monopersulphate, perborate monohydrate, perborate tetrahydrate, and percarbonate.
  • the coating materials which are suitable for encapsulating the bleach core particles are paraffin waxes which have low melting points, i.e. between 35°C, preferably 40°C, and 50°C and penetration values of from 10 to 60 mm at 25°C.
  • This melting point range for the coat is desirable for several reasons.
  • the minimum of 35°C (or more preferably 40°C) generally exceeds any storage temperatures that are encountered by cleaning compositions.
  • the wax coat will protect the bleach core throughout storage of the cleaning composition.
  • the 50°C melting point cap for the wax coat was selected as providing a wax which will quickly melt or soften early in any automatic dishwashing wash cycle. Melting or softening sufficient to release bleach core will occur because operating temperatures in automatic dishwashers are usually between 40 and 70°C. Thus, the paraffin waxes of the invention will release bleach when the capsule is exposed to the warmed wash bath, but not before.
  • melted paraffin waxes of the capsules of the invention will remain substantially molten at 40-50°C.
  • Such molten wax is easily emulsified by surfactant elements in cleaning compositions. Consequently, such waxes will leave less undesirable waxy residue on items to be cleaned than waxes with higher melting points.
  • paraffin waxes have a melting point range of roughly 30 to 80°C and are constituted largely of normal alkanes with low levels of isoalkanes and cycloalkanes. Isoalkanes and cycloalkanes contribute to lack of order in solid wax structures and paraffin waxes are largely crystalline when solid. Thus, the wax coat should not include any paraffins having melting point substantially above 50°C, lest the higher melting point components remain solid throughout the wash cycle and form unsightly residues on surfaces to be cleaned.
  • the amount of solids in a wax at any given temperature may be determined by Differential Scanning Calorimetry.
  • the wax solids content as measured by Differential Scanning Calorimetry for suitable paraffin waxes may range from 100 to 40%, optimally from 100 to 75%, at 40°C and from 0-15%, and preferably 0-5% at 50°C.
  • micro-crystalline waxes In contrast to paraffin waxes, micro-crystalline waxes have generally higher molecular weights and melting points. Thus, the melting point range for micro-crystalline waxes is from about 50 to about 100°C. Moreover, micro-crystalline waxes are more viscous in the molten state than paraffin waxes and softer than paraffin waxes when solid. Particles coated with micro-crystalline waxes would therefore have a poorer protective coating, and the wax coat which melts from such particles would be less likely to emulsify in cleaning compositions. Thus, micro-crystalline waxes are not considered within the operative scope of this invention.
  • the Penetration Test (ASTM D-1321) is the standard industrial test for hardness of waxes. This test measures the depth in tenths of a millimeter that a needle of a certain configuration under a given weight penetrates the surface of a wax at a given temperature. Paraffin waxes suitable for use in encapsulating the bleach particles have penetration values of from 10 to 60 mm at 25°C.
  • paraffin waxes which are suitable for encapsulating bleach particles include Merck 7150 and 7151, ex E. Merck of Darmstadt, West Germany; Boler 1397 ex Boler (penetration value of 40 mm at 250°C); Ross fully refined paraffin wax 115/120 ex Frank D. Ross Co., Inc. (penetration value of 40-50 mm at 25°C); and Altafin trade marks "Okerin-2033" trade marks of Durachem Inc. (penetration value of 15-20 mm at 25°C). Most preferred is Boler 1397.
  • the process for forming a coherent, continuous coating around bleach particles suitable for use in cleaning compositions comprises:
  • the amount of coating applied to the bleach core particles is typically from 35 to 55%, preferably 45 to 50% by weight of the total particle (i.e. core plus coating).
  • the coating is applied in a fluidised bed.
  • a fluidised bed There are several methods of operating a fluidised bed. In a common fluidised bed operation, air is introduced into the bed from below while the coating material is sprayed on to the fluidised material from above. The particles move randomly in the bed in this top spray operation.
  • the resulting material can be poorly coated or, alternatively, agglomerated together.
  • These equally undesirable results follow from the temperature settings in operating the fluidized bed. For example, when the temperature of the bed is too far below that of the molten wax, the molten wax begins to solidify as soon as it enters the cool bed region. Thus, the wax loses some of its ability to adhere to the surface of the bleach particles, and the wax itself quickly solidifies. When this occurs, the fluidized bed is operating to spray dry the wax, with the result that little or none of the wax coats the bleach. The poorly coated bleach particles consequently have little stability from ambient humidity or an aqueous liquid environment.
  • the bed temperature is from at least 20°C to no higher than the melting point of the wax, "spray drying" of the wax and agglomeration of coated bleach particles is reduced.
  • the bed temperature is 20 to 35°C, and most preferably 25 to 32°C.
  • atomization temperature or the temperature at which the wax is sprayed from a nozzle on to the fluidized bed, is advantageously held at from 5 to 40°C, preferably from 5 to 10°C, above the melting point of the wax.
  • the maximum atomization temperature is about 35°C greater than the wax melting point; above this temperature, too great a percentage of the particles agglomerate.
  • the Wurster mode is used to coat particles, the atomization temperature may be as high as 50°C and more above the wax melting point temperature. This is found to be a practicable atomization temperature, despite the expectation that partially coated particles with molten coats would stick to the spray nozzle.
  • the air flow is strong enough to detach these partially coated particles.
  • the temperature of the molten wax may be maintained substantially above the wax melting point, e.g. from 50 to 100°C above the melting point.
  • the atomization temperature is preferably near or even below the melting temperture of the wax, in order to lower the wax temperature sufficiently to solidify quickly on bleach particles in the fluidized bed.
  • the preferred encapsulation method of this invention produces coated particles which have an average diameter ranging from 800 to 4,000 ⁇ m.
  • An alternative to the top spray of molten coating material is the Wurster spray mode.
  • This method is described in detail in U.S. Patent 3,253,944.
  • fluidized beds are characterized by randomness of particle motion. Random motion is undesirable when coating particles because of the resultant slow coating rates.
  • a cyclic flow pattern is established in the Wurster spray mode by controlled velocity differences.
  • the Wurster mode involves use of a vertically disposed coating tower wherein particles are suspended in an upwardly flowing air stream entering the bottom of the tower. This air stream imparts controlled cyclic movement to the particles with a portion of the suspended bed flowing upwardly inside the tower and the other portion downwardly outside the tower. All of the coating material is directed into the high velocity air stream to provide coating of the particles moving upwardly in the tower.
  • the fluid coating solidifies on the surface of the particles as the air stream lifts them away from the nozzle.
  • the particles are carried to the top of the tower, from which point they fall to the base of the tower along a path outside the tower. At the base, the particles are drawn in through openings and re-directed upwardly in the air stream inside the tower. This cycle is repeated until the desired amount of coating has been deposited on the particles.
  • the spray nozzle for Wurster is located at the bottom of the fluidized bed and sprays coating materials upwards. It was believed this configuration of the spray nozzle would lead to clogging of the spray noz zle when coated and agglomerated particles fell from the upward air spray into the nozzle area. This risk seemed especially high because the nozzle temperature is generally above the melting point of the wax coating.
  • Applicants have surprisingly discovered that use of the Wurster spray mode results in many benefits.
  • agglomeration of coated bleach particles may be further reduced when operating a fluid bed in the Wurster method. Whereas some 5-15% of the particles coated by top spray may agglomerate, and so be unusable, the level of agglomerated particles from the Wurster application of a fluidized bed does not usually exceed 5% of the particles.
  • the coating time under Wurster can take half as long as top spray, or less, even with a substantially lower air flow rate, as demonstrated in Example I below.
  • the production rate of the encapsulated bleach particles may be as much as 2 to 3 times higher by the Wurster mode. This higher production rate may be maintained even when the air flow rate through the fluidized bed is lower than for the top spray mode.
  • higher production rates with lower air flow rates in the Wurster mode produce particles with less agglomeration than the top spray mode.
  • annealing is the name given to a further heating of wax-encapsulated bleach particles at a temperature greater than room temperature but below the wax melting point. This heating step is performed with the bed being fluidized, i.e. with warm air flowing through it; however, no molten wax is being sprayed on to the particles during annealing.
  • the annealing step renders the wax mobile enough that it fills in gaps and cracks in its surface, thus providing a better seal to the bleach within.
  • the temperature chosen for annealing is one which softens the wax without rendering it sticky. Typically, this temperature is from 5 to 15°C greater than the bed temperature during coating, and from 3 to 15°C less than the melting point of the wax coating. For example, when the wax has melting point of 46°C, the annealing temperature may be about 33-34°C.
  • the bed temperature during spraying is only about 31-32°C, for above 32°C there is a good chance of the particles agglomerating: the high temperature of the molten wax, combined with an annealing temperature, would so soften the wax that particles would agglomerate in the fluidized bed. However, when no hot molten wax is being sprayed on to the particles, an annealing temperature alone in the bed is not warm enough to cause agglomeration.
  • annealing should be performed for a period between 10 minutes and 48 hours, optimally between about 1 and 24 hours, eg. between 10 and 45 minutes, after spraying is complete.
  • an inert material such as an amorphous silica, alumina or clay, prevents capsule sticking during the annealing process.
  • Incorporation of the inorganic annealing adjunct allows use of higher temperatures during the annealing process, thus shortening the annealing period.
  • Adjuncts may be used in an amount relative to the weight of the overall capsule in the ratio of 1:200 to 1:20, preferably 1:100.
  • a further advantage discovered by Applicants in using the Wurster spray mode is that no annealing step is needed. More accurately, self-annealing occurs automatically as part of the coating process when the Wurster mode is used.
  • the hot molten wax droplet contacting the partly coated bleach particle causes the solid wax already on the particle to melt and to fill any cracks in the wax surface.
  • the particles in the Wurster mode move out of the spray tower and fall through the less crowded space outside the tower. In this space, the particles have time to cool slowly.
  • the smaller charge of bleach particles to be coated in Wurster also reduces the likelihood of contacting other particles while cooling. The result is annealing as part of the coating process.
  • the wax-encapsulated bleach capsules of the invention may be incorporated into a variety of cleaning compositions.
  • These compositions include fabric washing, fabric softening, automatic machine dishwashing, light duty dishwashing and hard surface cleaning powder and liquid compositions.
  • These compositions will contain from 0.1 to 30%, preferably from 0.1 to 15%, by weight of the encapsulated bleach particles, from 1-75% of a builder component and optionally 0.001 to 5% of a perfume component.
  • Certain of the foregoing type of products will also contain from 0.01 (preferably 0.1) to 15% of a surfactant, preferably from 0.5% to 10% by weight of the composition.
  • Wax-encapsulated chlorine bleach is especially suitable for automatic dishwashing liquid or "gel" detergent products where capsules will be present in an amount of 0.1 to 20, preferably 0.1 to 15%, by weight of the composition.
  • Automatic dishwashing detergent powders and liquids will have the preferred composition listed in Table I.
  • Gels differ from liquids in that gels are primarily structured by polymeric materials and contain only low levels of clay.
  • the cleaning compositions of this invention can contain all manner of detergent builders commonly taught for use in automatic dishwashing or other cleaning compositions.
  • the builders can include any of the conventional inorganic and organic water-soluble builder salts, or mixtures thereof, and may comprise from 1 to 75%, preferably from 5 to 75%, by weight of the cleaning composition.
  • Typical of the well-known inorganic builders are the sodium and potassium salts of the following: pyrophosphate, tripolyphosphate, orthophosphate, carbonate, bicarbonate, sesquicarbonate and borate.
  • Other non-phosphorus salts including crystalline and amorphous aluminosilicates may be used as well.
  • Particularly preferred builders can be selected from the group consisting of sodium tripolyphosphate, sodium carbonate, sodium bicarbonate and mixtures thereof. When present in these compositions, sodium tripolyphosphate concentrations will range from 2% to 40%, preferably from 5% to 30%. Sodium carbonate and bicarbonate, when present, can range from 10% to 50%, preferably from 20% to 40% by weight of the cleaning compositions. Potassium pyrophosphate is a preferred builder in gel formulations, where it may be used at from 3 to 30%, preferably from 10 to 20%.
  • Organic detergent builders can also be used in the present invention. They are generally sodium and potassium salts of the following: citrate, nitrilotriacetates, phytates, polyphosphonates, oxydisuccinates, oxydiacetates, carboxymethyloxy succinates, tetracarboxylates, starch, oxidized heteropolymeric polysaccharides, and polymeric polycarboxylates such as polyacrylates of molecular weight of from about 5,000 to about 200,000. Polyacetal carboxylates such as those described in U.S. Patents Nos. 4,144,226 and 4,146,495 may also be used.
  • Sodium citrate is an especially preferred builder. When present, it is preferably available from 1% to 35% of the total weight of the detergent composition.
  • detergent builders are meant to illustrate but not limit the types of builder that can be employed in the present invention.
  • Surfactants may be incorporated in the household cleaning product incorporating the encapsulated bleach particles.
  • Useful surfactants include anionic, nonionic, cationic, amphoteric, zwitterionic types and mixtures of these surface-active agents. Such surfactants are well known in the detergent art and are described at length in "Surface Active Agents and Detergents", Vol. II, by Schwartz, Perry & Birch, Interscience Publishers, Inc. 1959.
  • Anionic synthetic detergents can be broadly described as surface active compounds with one or more negatively charged functional groups. Soaps are included within this category.
  • a soap is a C 8 -C 22 alkyl fatty acid salt of an alkali metal, alkaline earth metal, ammonium, alkyl-substituted ammonium or alkanol ammonium salt. Sodium salts of tallow and coconut fatty acids and mixtures thereof are most common.
  • anionic compounds are the water-soluble salts, particularly the alkali metal salts, of organic sulphur reaction products having in their molecular structure an alkyl radical containing from about 8 to 22 carbon atoms and a radical selected from the group consisting of sulphonic and sulphuric acid ester radicals.
  • Organic sulphur-based anionic surfactants include the salts of C 10 -C 16 alkylbenzene sulphonates, C 10 -C 22 alkane sulphonates, C 10 -C 22 alkyl ether sulphates, C 10 -C 22 alkyl sulphates, C 4 -C 10 dialkylsulphhosuccinates, C 10 -C 22 acyl isethionates, alkyl diphenyloxide sulphonates, alkyl napthalene sulphonates, and 2-acetamido hexadecane sulphonates.
  • Organic phosphate-based anionic surfactants include organic phosphate esters such as complex mono- or di-ester phosphates of hydroxyl-terminated alkoxide condensates, or salts thereof. Included in the organic phosphate esters are phosphate ester derivatives of polyoxyalkylated alkylaryl phosphate esters, of ethoxylated linear alcohols and ethoxylates of phenol.
  • a surfactant which is particularly suitable for combination in cleaning compositions with the wax-encapsulated bleach is Emphos CS-1361®, believed to be complex mono- or di-ester of ethoxylated nonyl phenols ex Witco Chemical Co., Inc. Also included are nonionic alkoxylates having a sodium alkylene carboxylate moiety linked to a terminal hydroxyl group of the nonionic through an ether bond. Counter-ions to the salts of all the foregoing may be those of alkali metal, alkaline earth metal, ammonium, alkanolammonium and alkylammonium types.
  • Nonionic surfactants can be broadly defined as compounds produced by the condensation of alkylene oxide groups with an organic hydrophobic material which may 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.
  • Illustrative, but not limiting examples, of various suitable nonionic surfactant types are:
  • nonionic surfactants having the formula: wherein R is a linear alkyl hydrocarbon having an average of 6 to 10 carbon atoms, R' and R" are each linear alkyl hydrocarbons of about 1 to 4 carbon atoms, x is an integer from 1 to 6, y is an integer from 4 to 15 and z is an integer from 4 to 25.
  • R is a linear alkyl hydrocarbon having an average of 6 to 10 carbon atoms
  • R' and R" are each linear alkyl hydrocarbons of about 1 to 4 carbon atoms
  • x is an integer from 1 to 6
  • y is an integer from 4 to 15
  • z is an integer from 4 to 25.
  • a particularly preferred example of this category is Poly-Tergent SLF-18, a registered trademark of the Olin Corporation, New Haven, Conn.
  • Poly-Tergent SLF-18 has a composition of the above formula where R is a C 6 -C 10 linear alkyl mixture, R' and R" are methyl, x averages 3,
  • Amphoteric synthetic detergents can be broadly described as derivatives of aliphatic and tertiary amines, in which the aliphatic radical may be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to about 18 carbons and one contains an anionic water-solubilizing group, i.e. carboxy, sulpho, sulphato, phosphato or phosphono.
  • an anionic water-solubilizing group i.e. carboxy, sulpho, sulphato, phosphato or phosphono.
  • Examples of compounds falling within this definition are sodium 3-dodecylamino propionate and sodium 2-dodecylamino propane sulphonate.
  • Zwitterionic synthetic detergents can be broadly described as derivatives of aliphatic quaternary ammonium, phosphonium and sulphonium compounds in which the aliphatic radical may be straight-chained or branched, and wherein one of the aliphatic substituents contains from about 8 to about 18 carbon atoms and one contains an anionic water-solubilizing group, e.g. carboxy, sulpho, sulphato, phosphato or phosphono. These compounds are frequently referred to as betaines. Besides alkyl betaines, alkyl amino and alkyl amido betaines are encompassed within this invention. Cocoamido-propyl dimethyl betaine is a particularly useful surfactant.
  • the wax capsule After the wax capsule has melted, it remains molten or re-solidifies depending on the temperature of the washing medium. Whether in molten or solid state, however, the wax may deposit on the surface of pieces being washed as a soil and impart a spotted, streaked or filmy appearance to those pieces. Wax may also build up on the surfaces in which cleaning is being performed, i.e. in sinks, bathtubs and automatic dishwashing machines.
  • This soiling by the wax coating may be reduced by incorporating one or more surfactants in the cleaning composition.
  • surfactants are polytergent SLF-18® ex Olin Corporation, and Emphos CS-1361® ex Witco Chemical; and Dowfax 2A-1® and Dowfax 3B-2®
  • a preferred embodiment of the cleaning composition comprises 0.1-30% by weight of wax-encapsulated bleach as described above; 1-75% builder; and 0.01-15% surfactant selected from the group consisting of polyoxyalkylated alkylaryl phosphate esters; mono- and di-C 8 -C 14 alkyl diphenyl oxide mono and/or di-sulphates; and nonionic surfactants of the formula where R is a C 6 -C 10 linear alkyl mixture, R' and R" are methyl, x averages 3, y averages 12 and z averages 16.
  • compositions of this invention may contain sodium or potassium silicate at a level of from 1 to 40%, preferably from 5 to 20% by weight of the cleaning composition.
  • This material is employed as a cleaning ingredient, source of alkalinity, metal corrosion inhibitor and protector of glaze on china tableware.
  • sodium silicate having a ratio of SiO 2 :Na 2 O of from about 1.0 to about 3.3, preferably from about 2 to about 3.2.
  • Some of the silicate may be in solid form.
  • An inert particulate filler material which is water-soluble may also be present in cleaning compositions in powder form. This material should not precipitate calcium or magnesium ions at the filler use level. Suitable for this purpose are organic or inorganic compounds.
  • Organic fillers include sucrose esters and urea.
  • Representative inorganic fillers include sodium sulphate, sodium chloride and potassium chloride.
  • a preferred filler is sodium sulphate. Its concentration may range from 0% to 60%, preferably about 10% to 20% by weight of the cleaning composition.
  • Thickeners are often desirable for liquid cleaning compositions.
  • Thixotropic thickeners such as smectite clays including montmorillonite (bentonite), hectorite, saponite, and the like may be used to impart viscosity to liquid cleaning compositions.
  • Silica, silica gel, and aluminosilicate may also be used as thickeners.
  • Salts of polyacrylic acid (of molecular weight of from about 300,000 up to 6 million), including polymers which are cross-linked may also be used, alone or in combination with other thickeners.
  • Use of clay thickeners for automatic dishwashing compositions is disclosed, for example, in U.S. Patent Nos.
  • a chlorine-stable polymeric thickener is particularly useful for liquid formulations with a "gel" appearance and rheology, particularly if a clear gel is desired.
  • U.S. Patent No. 4,260,528 discloses natural gums and resins for use in clear autodish detergents, which are not chlorine-stable.
  • Acrylic acid polymers that are cross-linked, manufactured by B.F. Goodrich and sold under the trade name "Carbopol” have been found to be effective for production of clear gels, and Carbopol 940, having a molecular weight of about 4,000,000 is particularly preferred for maintaining high viscosity with excellent chlorine stability over extended periods.
  • Further suitable chlorine-stable polymeric thickeners are described in US-A- 4 867 896 (Elliott et al).
  • the amount of thickener employed in the composition is from 0 to 5%, preferably 1-3%.
  • Stabilizers and/or co-structurants such as long-chain calcium and sodium soaps and C 12 to C 18 sulphates are detailed in U.S. Patents Nos. 3,956,158 and 4,271,030 and the use of other metal salts of long-chain soaps is detailed in U.S. Patent No. 4,752,409.
  • the amount of stabilizer which may be used in the liquid cleaning compositions is from about 0.01 to about 5% by weight of the composition, preferably 0.1-2%.
  • Such stabilizers are optional in gel formulations.
  • Co-structurants which are found especially suitable for gels include trivalent metal ions at 0.01-4% of the composition and/or water-soluble structuring chelants at 1-60%. These co-structurants are more fully described in US-A- 4 836 948 (Corring et al).
  • Liguid and "gel" formulations of 'the cleaning composition comprising surfactant may further include a defoamer.
  • Suitable defoamers include mono- and distearyl acid phosphate, silicone oil and mineral oil. Even if the cleaning composition has only defoaming surfactant, the defoamer assists to minimize foam which food soils can generate.
  • the composition may include 0.2 to 2% by weight of defoamer, or preferably 0.05-1.0%.
  • Minor amounts of various other components may be present in the cleaning composition. These include flow control agents (in granular forms), soil-suspending agents, anti-redeposition agents, anti-tarnish agents, enzymes (e.g. protease, amylase and/or lipase at 0.05-2% by weight, preferably 0.5-1.5%) and other functional additives and perfume.
  • the pH of the cleaning composition may be adjusted by addition of strong acid or base.
  • Batch B is coated with 100% Boler 1397 wax applied in a fluidized bed at the following settings: Batch B Spray Mode Wurster Unit Glatt GPCG-5 Partition Height 2.5 cm (1.0") Nozzle tip diameter 1.2 mm Volume 10.5 liter Bed Weight 8 Kg (17.5 lbs.) Air Flow Rate 0.94x10 5 -1.27x10 5 cm 3 /S (200-270 cfm) Inlet Air Temperature 18-24°C Bed Temperature 30-31°C Coating Rate 72 g/min Coating Temperature 75-80°C Atomization Air Pressure 1.5x10 5 Pa (1.5 Bar) Atomization Air Temperature 80-90°C Batch Time 70 mins
  • the encapsulated CDB-56 of Batch B has excellent stability in autodidish liquid at 40°C and pH of 12.3.
  • coating compositions made from micro-crystalline wax and fatty acid in alkaline media may be contrasted to that of coating compositions made from one paraffin wax having melting point between 40 and 50°C.
  • coating compositions made from one paraffin wax having melting point between 40 and 50°C Four different coating compositions are made from a microcrystalline wax with a pair of fatty acids in the proportions appearing below. Two different paraffin waxes are selected for comparison. The four fatty acid/wax and the two waxes are identified as coating compositions 1 through 6 below.
  • Equal amounts (0.27 g) of each of coating compositions 1 through 6 are placed in separate beakers, which already contain 2.87 liters of a 0.02% aqueous solution of Emphos CS-1361®. The contents of each beaker are heated to 49°C, maintained at this temperature with stirring for 45 minutes, then cooled to room temperature and poured through a USA standard metal sieve with size 48 mesh (300 ⁇ m).
  • microcrystalline wax/fatty acid compositions leave large amounts of wax residues.
  • Comparison of Samples 1 to 2 and 3 to 4 shows that less wax is deposited from coating compositions with lower levels of Multiwax W145-A.
  • the paraffin waxes having melting point from 40-50°C leave very little residue, and hence are much preferred as coatings for bleach particles.
  • Bleach is encapsulated as in Example I but with coatings consisting of a wax melting at 72°C (30% Epolene C-16/70% Boler Paraffin 1426), 52°C (Altafin 125/130) or 46°C (Ross 115/120).
  • the capsules coated with the high-melting waxes are coated in a fluidized bed as are the capsules of Batch A in Example I, except that for capsules coated with Epolene, the bed temperature is 60-65°C and for capsules coated with Altafin 125/130 the bed temperature is 40-45°C.
  • the capsules coated with Ross 115/120 are prepared as are the capsules of Batch B in Example I. All three capsule batches are coated with a core:coat ratio of 47:53. Thus, in one gram of capsules, there should be 0.53 grams of wax.
  • This autodish gel formulation is as follows. Water is loaded into a vessel. The KOH is added with stirring for one minute, followed by the clay with further stirring for another 10 minutes. The blend ofTKPP, STP and Carbopol 941 is then added over the next 12 minutes, followed by 30 minutes of stirring. The TKPP solution is then added and the mixture is stirred for 30 minutes. Then the D-silicate, K 2 CO 3 and SLF-18 are each added separately, each one being followed by 5 minutes of stirring.
  • the autodish liquid composition containing the bleach capsules is in turn placed in the dispenser cup of a Kenmore automatic dishwashing machine.
  • One 40 gram sample of autodish is placed in the dispensing cup of the dishwasher at a time and the machine is run through one complete cycle when empty.
  • the water draining from the machine is filtered through a U.S. standard metal sieve of 43 mesh (0.38 mm) into a bucket.
  • the captured wax capsules or particles are dried and weighed. The results appear in the table below and Figure 1.
  • Example III The same three capsule types made in Example III are here tested in preventing spotting on glassware washed in an automatic dishwashing machine. Glass appearance tests are run in Bosch S-512 dishwashers at 60°C (140°F) and using water of 120 ppm hardness.
  • the capsules are made in a Granuglatt apparatus, model number WSG-3 at the following settings: Spray Mode Wurster Initial Bed Charge 1,600 g Inlet Air Temperature 16-20°C Bed Temperature ca. 18-22°C Coating Rate 60-80 g/min Coating Temperature 75-80°C Atomization Air Pressure 1.5 Bar Atomization Air Temperature 79-88°C Batch Time 20-28 minutes Then 1.8 grams of each capsule are dispersed evenly throughout the automatic dishwashing liquid of Example III. Thus, six autodish liquid compositions containing the capsules are formed and each is stored at 40°C.
  • Samples are set up in triplicate in 113g (4 oz) glass jars. Chlorine analysis is carried out after 1, 2, 7, 14, 28, 42, and 56 days.
  • Capsules 3 and 4 have a melting point of 50°C and coating levels of 57 and 54 wt.% of the total capsule, respectively.
  • Capsule 4' has the same composition as that of capsule 4 except that its coating level is higher, namely 66%.
  • Capsules 5 and 6 have a coating level of 54%. The results show that fatty acid/ microcrystalline wax coatings protect bleach poorly in an alkaline medium. Thus, these coating materials are not suitable for use in aqueous alkaline media. By contrast, when the coating is a paraffin wax of melting point from 40 to 50°C, the level of bleach preserved in an alkaline medium is excellent.
  • the stability of bleach encapsulated in single wax coatings of different thickness is measured as follows: a batch of Clearon CDB 56 R is loaded into a fluidized bed and coated with enough Boler Paraffin 1397 so that the coat constitutes 35% of the encapsulated bleach (Batch A). A second batch (Batch B) of Clearon CDB 56 R is coated with sufficient Boler 1397 so that the coat is 55% of the particle. About one gram of each bleach encapsulate is then dispersed into 40 grams of the autodish composition of Example III and stored therein at 40°C.
  • Samples are set up in triplicate in 113g (4 oz) glass jars and stored at 40.2°C. Chlorine analysis is carried out at 1, 2, 4, and 6 weeks.
  • Example III The capsules of Example III are incorporated into the autodish liquid composition of Example III. Forty grams of each composition are loaded into the dispenser cup of a Kenmore automatic dishwashing machine and the machine is operated through one wash cycle at 46°C. Every two minutes through the wash cycle, a 5 ml aliquot is removed from the wash liquor. The level of available chlorine released from the capsules is measured by standard iodometric titration. As the results show ( Figure 3), the capsules having lower melting coats release bleach more quickly and more completely. Thus, these capsules demonstrate higher efficiency.

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Claims (14)

  1. Procédé de formation d'un enrobage cohérent, continu autour de particules de blanchiment appropriées pour emploi dans des compositions de nettoyage, ce procédé comprenant :
    a) la mise en suspension des particules de blanchiment dans un lit fluidisé,
    b) le choix d'une (ou plusieurs) cire de paraffine pour assurer l'enrobage, les cires ayant un point de fusion entre 35 et 50°C et une valeur de pénétration d'aiguille de 10 à 60 mm à 25°C,
    c) le chauffage d'une (ou plusieurs) paraffine à une température suffisamment au dessus de son point de fusion pour faire fondre toute la cire,
    d) la fluidisation du lit en faisant passer de l'air à travers les particules de blanchiment, de façon à maintenir une température de lit d'au moins 20°C à une température ne dépassant pas le point de fusion de la cire, et
    e) la pulvérisation de la cire de paraffine fondue sur le lit fluidisé à un taux de 10 à 40 g/min par kg de particules de blanchiment dans le lit fluidisé et pendant une durée suffisante pour former un enrobage ayant une épaisseur de 10 à 3000 µm sur les particules de blanchiment.
  2. Procédé selon la revendication 1, dans lequel, au stade (e), la cire de paraffine fondue est pulvérisée sur le lit fluidisé à une température d'atomisation de 5 à 40°C au dessus du point de fusion de la cire.
  3. Procédé selon la revendication 1, dans lequel la cire de paraffine est pulvérisée dans le lit fluidisé par le procédé Wurster comprenant la mise en suspension des particules dans un courant d'air s'écoulant vers le haut pénétrant par le fond du lit fluidisé pour conférer un mouvement cyclique réglé aux particules avec une portion du lit s'écoulant vers le haut.
  4. Procédé selon la revendication 1, comprenant en outre le recuit des particules enrobées à une température de 5 à 15°C plus élevée que celle de la température du lit pendant l'enrobage et de 3 à 15°C de moins que le point de fusion de l'enrobage de cire, pendant 10 minutes à 48 heures après achèvement de la pulvérisation.
  5. Procédé selon la revendication 1, dans lequel les particules encapsulées ont un diamètre moyen allant de 800 à 4000 µm.
  6. Procédé selon la revendication 1, dans lequel la cire de paraffine a une teneur en solides de 40 à 100% à 40°C et une teneur en solides de 0 à 15% à 50°C.
  7. Procédé selon la revendication 1, dans lequel, au stade (c) la (ou les) cire de paraffine est chauffée à une température de 50 à 100°C au dessus du point de fusion de la cire et la température d'atomisation de la cire pulvérisée sur le lit fluidisé est en dessous du point de fusion de la cire.
  8. Particule de blanchiment encapsulée avec de la cire appropriée pour incorporation dans des compositions de nettoyage, la particule encapsulée comprenant :
    a) de 45 à 65% en poids de la particule encapsulée finale d'un noyau particulaire solide d'agent de blanchiment,
    b) de 35 à 55% en poids de la particule encapsulée finale d'un enrobage cireux, l'enrobage comprenant une (ou plusieurs) cire de paraffine ayant un point de fusion de 35 à 50°C et une valeur de pénétration d'aiguille de 10 à 60 mm à 25°C et ayant 10 à 3000 µm d'épaisseur.
  9. Particule encapsulée selon la revendication 8, dans laquelle l'épaisseur de l'enrobage est de 200 à 750 µm.
  10. Particule encapsulée selon la revendication 8, dans laquelle l'agent de blanchiment est choisi parmi les agents libérant du chlore, les agents libérant du brome, et les composés produisant un peroxygène organiques et minéraux.
  11. Particule encapsulée selon la revendication 10, dans laquelle l'agent de blanchiment est le chlorisocyanurate.
  12. Composition de nettoyage liquide comprenant:
    a) 0,1 à 30% en poids de particules de blanchiment encapsulées de la revendication 8;
    b) 1 à 75% en poids d'adjuvant ;
    c) 0,01 à 15% en poids d'un tensioactif ;
    d) facultativement 1 à 40% en poids de silicate, et
    e) 15 à 95% en poids d'eau.
  13. Composition de nettoyage selon la revendication 12, dans laquelle la composition est un liquide de lavage de la vaisselle automatique comprenant :
    a) 10 à 60% en poids d'adjuvant ;
    b) 0,01 à 3% en poids de tensioactif non ionique ;
    c) 5 à 20% en poids de silicate ;
    d) 0,1 à 20% en poids de particules de blanchiment encapsulées de la revendication 8 ;
    e) 0 à 5% en poids d'épaississant ; et
    f) de l'eau en complément.
  14. Composition de nettoyage selon la revendication 12, dans laquelle le tensioactif est choisi parmi les mono et/ou di sulfates de mono et di alkyl(C8-14)diphényloxyde, les esters d'alkylarylphosphate polyoxyalkylé, les tensioactifs répondant à la formule :
    Figure imgb0005
     dans laquelle R est un mélange alkylique linéaire en C6-10, R' et R" sont méthyle, x est en moyenne 3, y est en moyenne 12 et z est en moyenne 16 et leurs mélanges.
EP90202882A 1989-11-15 1990-10-31 Particules de blanchiment encapsulées avec de la cire et procédé de préparation Expired - Lifetime EP0436971B1 (fr)

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AU (1) AU633645B2 (fr)
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Cited By (1)

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US9474720B2 (en) 2013-11-04 2016-10-25 BioPharmX, Inc. Dosage form comprising an active ingredient and a plurality of solid porous microcarriers

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US5336430A (en) * 1992-11-03 1994-08-09 Lever Brothers Company, Division Of Conopco, Inc. Liquid detergent composition containing biodegradable structurant
US5480577A (en) * 1994-06-07 1996-01-02 Lever Brothers Company, Division Of Conopco, Inc. Encapsulates containing surfactant for improved release and dissolution rates
EP0770121B1 (fr) * 1994-07-04 1999-05-06 Unilever N.V. Procede et composition de lavage
DE19727073A1 (de) * 1997-06-25 1999-01-07 Henkel Kgaa Umhüllte Reinigungsmittelkomponente
EP1149144A1 (fr) 1999-02-05 2001-10-31 Unilever Plc Procede utilise pour laver la vaisselle et compositions connexes
DE19918267A1 (de) * 1999-04-22 2000-10-26 Henkel Kgaa Handgeschirrspülmittel mit Mikrokapseln
US6406747B1 (en) * 2000-11-28 2002-06-18 Xerox Corporation Methods of encapsulating cores using ink jets or fogs
US20030176308A1 (en) * 2002-03-14 2003-09-18 Unilever Home & Personal Usa Detergent compositions containing components modified to float in water
KR100892551B1 (ko) 2006-02-15 2009-04-09 신명곤 점성 화장용 조성물의 이산화탄소 발생 및 피에이치 조절이가능한 마이크로캡슐화된 산의 제조방법
DE102006023937A1 (de) 2006-05-19 2007-11-22 Henkel Kgaa Verkapselte Bleichmittelteilchen

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BE597383A (fr) * 1959-11-24
FR2471222A1 (fr) * 1979-12-12 1981-06-19 Interox Procede pour la stabilisation de particules contenant des composes peroxygenes et compositions de blanchiment contenant des particules stabilisees selon ce procede
FR2548684B1 (fr) * 1983-07-08 1986-08-22 Charbonnages Ste Chimique Compositions detergentes contenant un derive chloroisocyanurique convenant pour le lavage de la vaisselle en machine a laver et leur procede de preparation
US4759956A (en) * 1987-05-22 1988-07-26 Lever Brothers Company Process for encapsulating particles using polymer latex
US4919841A (en) * 1988-06-06 1990-04-24 Lever Brothers Company Wax encapsulated actives and emulsion process for their production

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Publication number Priority date Publication date Assignee Title
US9474720B2 (en) 2013-11-04 2016-10-25 BioPharmX, Inc. Dosage form comprising an active ingredient and a plurality of solid porous microcarriers
US9642867B2 (en) 2013-11-04 2017-05-09 BioPharmX, Inc. Dosage form comprising an active ingredient and a plurality of solid porous microcarriers
US9901586B2 (en) 2013-11-04 2018-02-27 BioPharmX, Inc. Dosage form comprising an active ingredient and a plurality of solid porous microcarriers
US10159686B2 (en) 2013-11-04 2018-12-25 BioPharmX, Inc. Dosage form comprising an active ingredient and a plurality of solid porous microcarriers

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EP0436971A3 (en) 1991-07-31
DE69031824T2 (de) 1998-04-30
DE69031824D1 (de) 1998-01-29
ES2110407T3 (es) 1998-02-16
CA2029658A1 (fr) 1991-05-16
AU6597090A (en) 1991-05-23
EP0436971A2 (fr) 1991-07-17
BR9005786A (pt) 1991-09-24
JPH03185099A (ja) 1991-08-13
AU633645B2 (en) 1993-02-04

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