Patent Description:
Laundry treatment applications, such as laundry and fabric enhancing, as well as many other treatment applications, seek to provide freshness benefits to the treated surfaces. A common method of providing freshness benefits is to use a perfume microcapsule.

Perfume oil is often flammable, sometimes highly flammable, and the method of making the perfume microcapsule, as well as the method of transporting the perfume microcapsule needs to be carefully controlled to mitigate any flammable risks, including explosion risks.

The inventors have discovered that the addition of sodium chloride into an aqueous perfume microcapsule mixture that is subsequently spray-dried provides a salted spray-dried perfume microcapsule particle that has low flammable risk, including low risk of explosion, even during storage and transport.

<CIT> discloses a process for the manufacture of a perfumed coloured granular composition for use as speckles in a particulate laundry detergent composition, characterised in that it comprises the steps of:_(i) layering sodium chloride granular material with a finely divided porous particulate material; (ii) mixing an aqueous perfume emulsion and a colourant with the layered sodium chloride of step (i); and (iii) layering the resultant material with a finely divided porous particulate material. wherein the finely divided porous particulate material has a number average particle size of at most <NUM> microns and the total amount of layering agent is from <NUM> to <NUM> wt% based on the speckles.

The present invention provides a process of making a salted spray-dried perfume microcapsule particle, wherein the process comprises the steps:.

Step (a) prepares an aqueous perfume microcapsule mixture comprising from 20wt% to 70wt% perfume microcapsules.

The aqueous perfume microcapsule mixture can be prepared by combining a perfume with a shell material in water to form an emulsion, and then encapsulating the perfume with the shell material to form an aqueous perfume microcapsule mixture.

Other ingredients may be present, for example an initiator, and a partitioning modifier, pH adjuster, an emulsifier, a deposition aid, a structurant, and any combination thereof.

The encapsulation of the perfume can occur by heating the emulsion in one or more heating steps to form a shell encapsulating the perfume core, thereby forming perfume microcapsules that are typically dispersed in an aqueous continuous phase.

Step (a) can be carried out in any suitable equipment, including continuous stirred tank reactors, homogenizers, turbine agitators, recirculating pumps, paddle mixers, plough shear mixers, ribbon blenders, vertical axis granulators and drum mixers, both in batch and, where available, in continuous process configurations, and extruders.

Step (b) contacts sodium chloride to the aqueous perfume microcapsule mixture to form a salted aqueous perfume microcapsule mixture comprising from <NUM>. 0wt% to 10wt% said sodium chloride.

Step (b) is preferably carried out in a mixer.

Step (b) may be carried out in a mixer having a tip speed of from <NUM>-<NUM> to <NUM>-<NUM>.

Step (b) may be carried out in a mixer having a power to volume ratio of from <NUM>
Wm-<NUM> to 20kWm-<NUM>.

Step (b) is carried out in a mixer, wherein said sodium chloride and said aqueous perfume microcapsule mixture are mixed together for at least five minutes, or from <NUM> minutes to <NUM> minutes, to form said salted aqueous perfume microcapsule mixture.

Other ingredients may be present, for example a deposition aid.

Step (c) spray-dries the salted aqueous perfume microcapsule mixture to form a salted spray-dried perfume microcapsule particle, wherein the salted spray-dried perfume microcapsule particle comprises from <NUM>. 0wt% to 20wt% said sodium chloride.

Step (c) is typically carried out in a spray-drying tower.

Step (c) can be carried out in a spray-drying tower having an air inlet temperature of from <NUM> to <NUM>, or from <NUM> to <NUM> or from <NUM> to <NUM>.

Step (c) can be carried out in a spray-drying tower, and wherein said salted aqueous perfume microcapsule mixture is sprayed into said spray-drying tower by a means selected from:.

The aqueous perfume microcapsule mixture comprises from 20wt% to 70wt% perfume microcapsules, preferably from 30wt% to 60wt% perfume microcapsules, or from 40wt% to 50wt% perfume microcapsules.

The aqueous perfume microcapsule mixture may comprise from 30wt% to 80wt%, or from 40wt% to 70wt%, or from 50wt% to 60wt% water.

The aqueous perfume microcapsule mixture may comprise other ingredients, for example an initiator, and a partitioning modifier, pH adjuster, an emulsifier, a deposition aid, and any combination thereof.

The salted aqueous perfume microcapsule mixture comprises from <NUM>. 0wt% to 10wt% said sodium chloride.

Preferably, the salted aqueous perfume microcapsule mixture comprises from <NUM>. 0wt% to <NUM>. 0wt%, or from <NUM>. 0wt% to <NUM>. 0wt%, or from <NUM>. 0wt% to <NUM>. 0wt% said sodium chloride.

The salted aqueous perfume microcapsule mixture may comprise a deposition aid.

The perfume microcapsule typically comprises a shell material that encapsulates a perfume core of perfume raw materials.

The salted perfume microcapsule typically comprises a shell material that encapsulates a perfume core of perfume raw materials.

The salted spray-dried perfume microcapsule particle, wherein the salted spray-dried perfume microcapsule particle comprises from <NUM>. 0wt% to 20wt% said sodium chloride, or from <NUM>. 0wt% to 20wt%, or from <NUM>. 0wt% to 15wt%, or from <NUM>. 0wt% to 10wt% said sodium chloride.

The salted spray-dried perfume microcapsule particle may have a particle size distribution such that the D<NUM> particle size is in the range of from <NUM> to <NUM>. The salted spray-dried perfume microcapsule particle may have a particle size distribution such that the D<NUM> particle size is in the range of from <NUM> to less than <NUM>. The salted spray-dried perfume microcapsule particle may have a particle size distribution such that the D<NUM> particle size is in the range of from greater than <NUM> to less than <NUM>. The particle size is typically determined by laser diffraction.

The salted spray-dried perfume microcapsule particle may have a bulk density in the range of from <NUM>/l to <NUM>. The bulk density is typically measured by a cup density method. A suitable method is as follows: A <NUM> cup is filled with the powder using a funnel to enable free flowing of the powder. A spatula is used to remove excess powder exceeding the dimensions of the cup. The weight of powder in the cup is measured (in grams) using a balance and divided by the <NUM> to calculate the density (in g/L).

The sodium chloride typically has a solubility saturation point at <NUM> in deionized water of greater than <NUM>/<NUM>, preferably greater than <NUM>/<NUM>, or greater than <NUM>/<NUM>, or greater than <NUM>/<NUM>, or greater than <NUM>/<NUM>.

Any perfume raw material, or combinations thereof, can be used as core material(s) for the perfume microcapsule. Particularly suitable perfume raw materials are disclosed below.

The shell material preferably comprises a polyacrylate polymer. The shell material can comprise from about 50wt% to about 100wt%, more preferably from about 70wt% to about 100wt%, more preferably from about 80wt% to about 100wt%, by weight of the shell material, of polyacrylate polymer.

The shell material can optionally further comprise polyvinyl alcohol. The shell material can comprise from about <NUM>. 5wt% to about 40wt%, preferably from about <NUM>. 5wt% to about 20wt%, preferably from about <NUM>. 5wt% to about 10wt%, preferably from about <NUM>. 8wt% to about 5wt%, by weight of the shell material, of polyvinyl alcohol.

The polyacrylate polymer of the shell material can be derived from a material that comprises one or more multifunctional acrylate moieties. Preferably the multifunctional acrylate moiety is selected from group consisting of tri-functional acrylate, tetra- functional acrylate, penta-functional acrylate, hexa-functional acrylate, hepta-functional acrylate, and mixtures thereof.

The polyacrylate polymer can optionally comprise a moiety selected from the group consisting of an amine acrylate moiety, methacrylate moiety, a carboxylic acid acrylate moiety, carboxylic acid methacrylate moiety, and combinations thereof.

The polyacrylate polymer can be derived from a material that comprises one or more multifunctional acrylate and/or optionally a material that comprises one or more methacrylate moieties, wherein the ratio of material that comprises one or more multifunctional acrylate moieties to material that comprises one or more methacrylate moieties is from about <NUM>:<NUM> to about <NUM>:<NUM>, more preferably from about <NUM>:<NUM> to about <NUM>:<NUM>, and more preferably from about <NUM>:<NUM> to about <NUM>:<NUM>. Preferably the multifunctional acrylate moiety is selected from group consisting of tri-functional acrylate, tetra- functional acrylate, penta-functional acrylate, hexa-functional acrylate, hepta-functional acrylate, and mixtures thereof. The polyacrylate polymer can optionally comprise a moiety selected from the group consisting of an amine acrylate moiety, methacrylate moiety, a carboxylic acid acrylate moiety, carboxylic acid methacrylate moiety, and combinations thereof.

The polyacrylate polymer of the shell material preferably comprises a cross-linked polyacrylate polymer.

The polyvinyl alcohol of the shell material, when present, preferably has one or more of the following properties:.

Other suitable shell materials include polyethylenes, polyamides, polystyrenes, polyisoprenes, polycarbonates, polyesters, polyureas, polyurethanes, polyolefins, polysaccharides, epoxy resins, vinyl polymers, and mixtures thereof.

Other suitable shell materials are selected from the group consisting of reaction products of one or more amines with one or more aldehydes, such as urea cross-linked with formaldehyde or gluteraldehyde, melamine cross-linked with formaldehyde; gelatin-polyphosphate coacervates optionally cross-linked with gluteraldehyde; gelatin-gum arabic coacervates; cross-linked silicone fluids; polyamine reacted with polyisocyanates; acrylate monomers polymerized via free radical polymerization, and mixtures thereof.

Any suitable deposition aids can be used. A preferred deposition aid is chitosan.

The chitosan is a linear polysaccharide comprising randomly distributed β-(<NUM>,<NUM>)-linked D-glucosamine (deacetylated unit) and N-acetylglucosamine (acetylated unit) and generally has the following structure:
<CHM>
<MAT> wherein n and m vary depending on the average molecular weight of the chitosan and the degree of deacetylation of the chitosan. The degree of deacetylation (% deacetylation) of the chitosan is equal to 100n/(n+m).

Suitable chitosan can have a weight average molecular weight of at least about <NUM> kDa (kilodaltons) and/or a degree of deacetylation of at least about <NUM>%.

Suitable chitosan can have lower degree of deacetylation values if the chitosan has relatively higher weight average molecular weight. The chitosan may also have lower weight average molecular weight values if the chitosan has relatively higher degree of deacetylation values. Preferred chitosans have degree of deacetylation values and weight average molecular weight values that are both relatively high, which tend to exhibit lower solubility in pH buffer solution across the pH range of <NUM>-<NUM>.

Suitable chitosan can have a degree of deacetylation of at least about <NUM>% and a weight average molecular weight of at least about <NUM> kDa.

Suitable chitosan can have a weight average molecular weight of at least about <NUM> kDa and a degree of deacetylation of at least about <NUM>%.

Suitable chitosan can have a degree of deacetylation of at least about <NUM>%, preferably at least about <NUM>%, and preferably at least about <NUM>%.

Suitable chitosan can have a weight average molecular weight of at least about <NUM> kDa, preferably at least about <NUM> kDa, and preferably at least about <NUM> kDa.

Typically, the amine group of chitosan has a pKa of about <NUM> and results in protonation of the chitosan in acidic to neutral solutions, with the charge density largely dependent upon the degree of deacetylation of the chitosan and the pH of solution. As such, the chitosan is typically cationic and can readily bind to anionically charged surfaces.

The chitosan is generally disposed on the outer surface of the salted perfume microcapsule particle.

Other deposition aids may comprise a polymer selected from the group comprising: polysaccharides, cationically modified starch, and/or cationically modified guar; polysiloxanes; poly diallyl dimethyl ammonium halides; copolymers of poly diallyl dimethyl ammonium chloride and polyvinyl pyrrolidone; a composition comprising polyethylene glycol and polyvinyl pyrrolidone; acrylamides; imidazoles; imidazolinium halides; polyvinyl amine; copolymers of poly vinyl amine and N-vinyl formamide; polyvinyl formamide, polyvinyl alcohol; polyvinyl alcohol crosslinked with boric acid; polyacrylic acid; polyglycerol ether silicone cross-polymers; polyacrylic acids, polyacrylates, copolymers of polyvinylamine and polvyinylalcohol oligomers of amines, in one aspect a diethylenetriamine, ethylene diamine, bis(<NUM>-aminopropyl)piperazine, N,N-Bis-(<NUM>-aminopropyl)methylamine, tris(<NUM>-aminoethyl)amine and mixtures thereof; polyethyleneimine, a derivatized polyethyleneimine, in one aspect an ethoxylated polyethyleneimine; a polymeric compound comprising, at least two moieties selected from the moieties consisting of a carboxylic acid moiety, an amine moiety, a hydroxyl moiety, and a nitrile moiety on a backbone of polybutadiene, polyisoprene, polybutadiene/styrene, polybutadiene/acrylonitrile, carboxyl-terminated polybutadiene/acrylonitrile or combinations thereof; pre-formed coacervates of anionic surfactants combined with cationic polymers; polyamines and mixtures thereof.

The compositions of the present disclosure may contain a rheology modifier and/or a structurant. Rheology modifiers may be used to "thicken" or "thin" liquid compositions to a desired viscosity. Structurants may be used to facilitate phase stability and/or to suspend or inhibit aggregation of particles in liquid composition, such as the delivery particles as described herein.

Suitable rheology modifiers and/or structurants may include non-polymeric crystalline hydroxyl functional structurants (including those based on hydrogenated castor oil), polymeric structuring agents, cellulosic fibers (for example, microfibrillated cellulose, which may be derived from a bacterial, fungal, or plant origin, including from wood), di-amido gellants, or combinations thereof. A preferred structurant is microfibrilated cellulose, preferably of plant origin.

Polymeric structuring agents may be naturally derived or synthetic in origin. Naturally derived polymeric structurants may comprise hydroxyethyl cellulose, hydrophobically modified hydroxyethyl cellulose, carboxymethyl cellulose, polysaccharide derivatives and mixtures thereof. Polysaccharide derivatives may comprise pectine, alginate, arabinogalactan (gum Arabic), carrageenan, gellan gum, xanthan gum, guar gum and mixtures thereof. Synthetic polymeric structurants may comprise polycarboxylates, polyacrylates, hydrophobically modified ethoxylated urethanes, hydrophobically modified non-ionic polyols and mixtures thereof. Polycarboxylate polymers may comprise a polyacrylate, polymethacrylate or mixtures thereof. Polyacrylates may comprise a copolymer of unsaturated mono- or di-carbonic acid and C<NUM>-C<NUM> alkyl ester of the (meth)acrylic acid. Such copolymers are available from Noveon inc under the tradename Carbopol Aqua <NUM>. Cross-linked polymers, such as cross-linked polyacrylate and/or polymers and/or copolymers, such as those that further include nonionic monomers such as acrylamide or methacrylamide monomers, may be useful as structurants. Another suitable structurant is sold under the tradename Rheovis CDE, available from BASF.

Preferred structurant is microfibrilated cellulose.

Suitable partitioning modifiers are selected from the group consisting of vegetable oil, modified vegetable oil, isopropyl myristate, propan-<NUM>-yl tetradecanoate, and mixtures thereof. Suitable vegetable oils are selected from the group consisting of castor oil, soybean oil, and mixtures thereof. Suitable modified vegetable oils are selected from the group consisting of esterified vegetable oil, brominated vegetable oil, and mixtures thereof. Preferred partitioning modifiers are selected from isopropyl myristate, propan-<NUM>-yl tetradecanoate, and mixtures thereof.

Optionally, the water phase may include an emulsifier. Non-limiting examples of emulsifiers include anionic surfactants (such as alkyl sulfates, alkyl ether sulfates, and/or alkyl benzenesulfonates), nonionic surfactants (such as alkoxylated alcohols, preferably comprising ethoxy groups), polyvinyl alcohol, and/or polyvinyl pyrrolidone. It may be that solubilized chitosan can provide emulsifying benefits in the present applications.

Emulsifier, if employed, is typically from about <NUM> to <NUM>% by weight, preferably <NUM> to about <NUM>% by weight, more typically <NUM> to <NUM>% be weight, based on total weight of the aqueous phase.

The (meth)acrylate polymer of the polymer wall may be further derived, at least in part, from at least one free radical initiator, preferably at least two free radical initiators. The at least one free radical initiator may preferably comprise a water-soluble or water-dispersible free radical initiator. One or more free radical initiators can provide a source of free radicals upon activation.

The amount of initiator present may be from about <NUM>% to about <NUM>%, preferably from about <NUM>% to about <NUM>%, more preferably from about <NUM>% to about <NUM>%, even more preferably from about <NUM>% to about <NUM>%, even more preferably from about <NUM>% to about <NUM>%, <NUM> or more preferably from about <NUM>% to about <NUM>%, by weight of the polymer wall. The (meth)acrylate polymer of the polymer wall may be derived from a first initiator and a second initiator, wherein the first and second initiators are present in a weight ratio of from about <NUM>:<NUM> to about <NUM>:<NUM>, or preferably from about <NUM>:<NUM> to about <NUM>:<NUM>, or more preferably from about <NUM>:<NUM> to about <NUM>:<NUM>, or even more preferably from about <NUM>:<NUM> to about <NUM>:<NUM>.

Suitable free radical initiators may include peroxy initiators, azo initiators, peroxides, and compounds such as <NUM>,<NUM>'-azobismethylbutyronitrile, dibenzoyl peroxide. More particularly, and without limitation, the free radical initiator can be selected from the group of initiators comprising an azo or peroxy initiator, such as peroxide, dialkyl peroxide, alkylperoxide, peroxyester, peroxycarbonate, peroxyketone and peroxydicarbonate, <NUM>,<NUM>'-azobis (isobutylnitrile), <NUM>,<NUM>'-azobis(<NUM>,<NUM>-dimethylpentanenitrile), <NUM>,<NUM>'-azobis (<NUM>,<NUM>-dimethylvaleronitrile), <NUM>,<NUM>'-azobis(<NUM>-methylpropanenitrile), <NUM>,<NUM>'-azobis(<NUM>-methylbutyronitrile), <NUM>,<NUM>'-azobis (cyclohexanecarbonitrile), <NUM><NUM>,<NUM>'-azobis(cyanocyclohexane), benzoyl peroxide, decanoyl peroxide; lauroyl peroxide; benzoyl peroxide, di(n-propyl)peroxydicarbonate, di(sec-butyl) peroxydicarbonate, di(<NUM>-ethylhexyl)peroxydicarbonate, <NUM>,<NUM>-dimethyl-<NUM>-hydroxybutyl peroxyneodecanoate, a-cumyl peroxyneoheptanoate, t-amyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-amyl peroxypivalate, t-butyl peroxypivalate, <NUM>,<NUM>-dimethyl <NUM>,<NUM>-di (<NUM>-ethylhexanoyl peroxy)hexane, t20 amyl peroxy-<NUM>-ethyl-hexanoate, t-butyl peroxy-<NUM>-ethylhexanoate, t-butyl peroxyacetate, di-tamyl peroxyacetate, t-butyl peroxide, dit-amyl peroxide, <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-di-(tbutylperoxy) hexyne-<NUM>, cumene hydroperoxide, <NUM>,<NUM>-di-(t-butylperoxy)-<NUM>,<NUM>,<NUM>-trimethylcyclohexane, <NUM>,<NUM>-di-(t-butylperoxy)-cyclohexane, <NUM>,<NUM>-di-(t-amylperoxy)-cyclohexane, ethyl-<NUM>,<NUM>-di-(t-butylperoxy)-butyrate, t-amyl perbenzoate, t-butyl perbenzoate, ethyl <NUM>,<NUM>-di-(t-amylperoxy)-butyrate, and the like.

The power to volume ratio is typically determined by direct measurement of the electrical power supplied to the mixer motor divided by the volume of the aqueous mixture in the tank multiplied by the motor efficiency.

The water solubility of a substance is the saturation mass concentration of the substance in water at a given temperature. Water solubility is expressed in mass of solute per volume of solution, kg/m3 and/or g/<NUM>.

In a stepwise procedure, increasing amounts of the salt (approximately <NUM>) are added to <NUM> of de-ionised water at <NUM> ± <NUM>. After each addition of salt sample, the mixture is shaken for <NUM> minutes, and the pH is measured. This process is repeated until the pH is not alter by more than <NUM>% vs previous measurement.

Three liters of two slurry formulations A and B were prepared based on compositions given in Table <NUM> (percentage by weight). The slurry with perfume microcapsules was mixed with anhydrous silica using an impeller bench-top mixer for <NUM> (example A). The same mixing conditions and time were used to fully dissolve NaCl in the example B.

The mixture was sprayed dried in a spray-drying tower with a spinning wheel atomizer rotating at <NUM> rpm. The inlet air temperature was kept at <NUM> and the fluid flow was controlled to be within a <NUM>-<NUM> liters/min range. The resultant spray-dried particle compositions are given in Table <NUM>.

The resultant powder samples were assessed for the standard UN Test N. <NUM> - Combustible Solids, compromising on Screening Test (ST) and Burning Rate Test (BR). The result of ST corresponds to the propagation time for a length of <NUM> of the dried powder (mold <NUM> x <NUM> x <NUM>) after being approach by an ignition source. The BR test evaluates the propagation time for a length of <NUM> of the powder pile using identical mold after pouring <NUM> of a wetting solution.

Claim 1:
A process of making a salted spray-dried perfume microcapsule particle, wherein the process comprises the steps:
(a) preparing an aqueous perfume microcapsule mixture comprising from 20wt% to 70wt% perfume microcapsules;
(b) contacting sodium chloride to the aqueous perfume microcapsule mixture to form a salted aqueous perfume microcapsule mixture comprising from <NUM>.0wt% to 10wt% said sodium chloride; and
(c) spray-drying the salted aqueous perfume microcapsule mixture to form a salted spray-dried perfume microcapsule particle, wherein the salted spray-dried perfume microcapsule particle comprises from <NUM>.0wt% to 20wt% said sodium chloride.