Charge-modified chitosan cross-linked encapsulant

Abstract

An improved polyurea and chitosan core-shell delivery particle that encapsulates a benefit agent is described. Chitosan is pre-modified with a modifying compound, which is cationic, anionic or nonionic. Alternatively, modification is completed in situ. The modifying compound is selected from the group consisting of epoxides, aldehydes or alpha, beta-unsaturated compounds and reacts with the free amine moiety of the chitosan, covalently bound to the amine moiety of the chitosan via a CN bond. The modifying compound may contain an acidic group, a hydroxyl group, and a quaternary ammonium group. The reaction product of chitosan, a modifying compound, and an electrophile, preferably a polyisocyanate, produces microcapsules that have charge, improved release properties, improved compatibility, or enhanced degradation properties (e.g., in OECD Test Method 301B).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] Joint Research Statement

[0003] Encapsys, LLC and The Procter & Gamble Company entered into a joint research agreement on or about July 29, 2021, and the invention was made as a result of activities conducted between the parties within the scope of the joint research agreement in effect on or before the date of this invention. Technical Field

[0004] The present invention relates to methods of making delivery particles and to delivery particles produced by such methods. Background Art

[0005] Various processes and exemplary methods and materials for encapsulation, especially microencapsulation, are described in Schwantes (U.S. Patent No. 6,592,990), Nagai et al. (U.S. Pat. No. 4,708,924), Baker et al. (U.S. Patent No. 4,166,152), Wojciak (U.S. Patent No. 4,093,556), Matsukawa et al. (U.S. Patent No. 3,965,033), Matsukawa (U.S. Patent No. 3,660,304), Ozono (U.S. Patent No. 4,588,639), Irgarashi et al. (U.S. Patent No. 4,610,927), Brown et al. (U.S. Patent No. 4,552,811), Scher (U.S. Patent No. 4,285,720), Shioi et al. (U.S. Patent No. 4,601,863), Kiritani et al. (U.S. Patent No. 3,886,085), Jahns et al. (U.S. Patent Nos. 5,596,051 and 5,292,835), Matson (U.S. Patent No. 3,516,941), Chao (U.S. Patent No. 6,375,872), Foris et al. (U.S. Patent Nos. 4,001,140, ​​4,087,376, 4,089,802 and 4,100,103), Greene et al. (U.S. Patent Nos. 2,800,458, 2,800,457 and 2,730,456), Clark (U.S. Patent No. 6,531,156), Saeki et al.(U.S. Patent Nos. 4,251,386 and 4,356,109), Hoshi et al. (U.S. Patent No. 4,221,710), Hayford (U.S. Patent No. 4,444,699), Hasler et al. (U.S. Patent No. 5,105,823), Stevens (U.S. Patent No. 4,197,346), Riecke (U.S. Patent No. 4,622,267), Greiner et al. (U.S. Patent No. 4,547,429), and Tice et al. (U.S. Pat. No. 5,407,609) et al. and as taught by Herbig in the section entitled "Microencapsulation" in Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 16, pp. 438-463.

[0006] Each patent described throughout this application is incorporated herein by reference to the extent that each provides guidance regarding microencapsulation methods and materials.

[0007] Jabs et al. US Patent No. 4,847,152 teaches microcapsules with polyurea walls. The wall is the reaction product of an aromatic isocyanate and an isocyanate reactive group. The isocyanate reactive group may include diamines and polyamines such as N-hydroxyethylethylenediamine, ethylene-1,2-diamine.

[0008] Hotz et al. US Patent Publication No. 2013 / 0089590 teaches fragrance microcapsules having a polyurea wall. The shell is the reaction product of at least two difunctional isocyanates and a difunctional amine.

[0009] EP 1693104 Maruyyama Microcapsules having a polyurethane or polyurea wall obtained by polycondensation of polyfunctional isocyanates with polyfunctional amines are disclosed.

[0010] U.S. Patent 9,816,059 describes a polyurea capsule encapsulating an oil core, wherein the polyurea is the reaction product of a polyfunctional isocyanate and a polyfunctional amine. The polyfunctional amine may include hexamethylene diamine and other amines including chitosan. Chitosan is mentioned as a stabilizer, as a polyfunctional amine, as a coating, but there is no guidance or example of how to handle this difficult material.

[0011] Chitosan is a polysaccharide and can be a difficult material to utilize in microencapsulation methods. Chitosan is generally insoluble in water at a pH greater than 7, and is cationic at a pH below about 6.5. Chitosan is soluble in low pH acidic solutions (e.g., hydrochloric acid, lactic acid, propionic acid, succinic acid, acetic acid, citric acid, and phosphoric acid) to form a viscous solution that is difficult to handle, but is generally insoluble in water at a pH greater than 7. When the pH is below 4, the amino groups of chitosan promote electrostatic repulsion, and the polymer swells.

[0012] Dissolved polysaccharides have positively charged -NH3 + Chitosan forms aggregates with (poly)anions and chelates heavy metals.

[0013] There is a need in the art for polyurea-based delivery particles having improved properties, including better deposition efficiency, lower leakage as measured by lower free oil, and having a cationic charge at pH less than about 7. Improved polyurea wall materials become possible if chitosan can be adapted for use as a soluble cross-linking agent.

[0014] The present invention overcomes the above-mentioned deficiencies of the prior art by teaching an improved polyurea delivery particle cross-linked with chitosan. The chitosan is hydrolyzed by acid treatment, making it soluble even at pH greater than 5, making it useful for microencapsulation methods such as interfacial encapsulation.

[0015] Although chitosan is often mentioned in the art as a possible component of the wall-forming material in microencapsulation, there is little teaching on how to actually utilize this difficult-to-handle material.

[0016] Chitosan is generally insoluble in water, alkali and most organic solvents. Even under acidic low pH conditions, the solubility is generally less than 2 wt %. The composition is viscous, difficult to handle and requires a lot of dilution. Chitosan concentrations less than 2 wt % make the material unsuitable for interfacial microencapsulation.

[0017] Chitosan is insoluble at higher pH, and capsule formation under capsule forming conditions typically involves conditions of pH 7 or 9 or even more alkaline, rendering chitosan a substantially insoluble viscous mass unsuitable for interfacial encapsulation.

[0018] There is a need for chitosan polyurea compositions at higher concentrations of chitosan that overcome the technical challenges of processing chitosan and provide useful concentrations greater than 2 wt % in the aqueous phase to achieve successful chitosan urea polymer shell formation.

[0019] For example, Lei et al., 2013 / 0330292, although chitosan is mentioned as a cross-linking agent for preparing polyurea capsules, Lei does not provide any description of how to use chitosan. Chitosan is only soluble at low pH and insoluble at higher pH levels. As the pH increases, chitosan precipitates out of the solution. In addition, due to its high molecular weight, chitosan is a material that is extremely difficult to use as a cross-linking agent.

[0020] Bulgarelli et al. , WO 2019063515 attempts to overcome the shortcomings of Lei by adding chitosan in solid form. Bulgarelli teaches adding chitosan in the aqueous phase of the emulsion. Once a reaction temperature of 80°C is reached, unprotonated chitosan is added. The claims state that chitosan is added in solid form, however, Bulgarelli does not provide teaching of examples of how to achieve solubilization of solid chitosan. Chitosan is known to precipitate at alkaline pH or even at a pH above 5.

[0021] Polyurea delivery particles are described as being advantageous for some applications due to the absence of formaldehyde. The mechanical properties of the polyurea systems described to date do not have the core retention properties required for some challenging applications (e.g., detergents, cleaning agents, compositions containing surfactants, modifiers, or other materials that tend to negatively affect capsule performance upon long-term storage). It would be an advance in the art to have polyurea chitosans that successfully incorporate chitosan at higher concentrations than have been achievable to date; are stable in a variety of matrix materials; can be modified to produce encapsulates with customized surface charges; or exhibit lower leakage. The degradability, lower leakage, and improved storage stability of the compositions thus obtained would be beneficial.

[0022] Although cross-linked chitosan capsules have some benefits (e.g., being based on biocompatible materials), they also have some disadvantages under some conditions of use. For example, chitosan capsules have been found to exhibit poor compatibility with some matrices (e.g., laundry detergent matrices, particularly liquid laundry detergents).

[0023] The present invention solves the problem of incompatibility of cross-linked chitosan capsule slurries in laundry matrices.The present invention teaches cross-linked chitosan capsules that can be modified to carry surface charges.

[0024] Incompatibility with some matrices can be overcome by modifying the surface charge of the encapsulate to increase or decrease the zeta potential. Aggregation can be reduced or even eliminated, while leakage can be reduced.

[0025] definition

[0026] For ease of reference in this specification and claims, the terms "monomer" or "monomers" as used herein with respect to the structural material forming the wall polymer of the delivery particle are to be understood as monomers, but also include oligomers and / or prepolymers formed from the specific monomer.

[0027] As used herein, the term "water-soluble material" means a material having a solubility of at least 0.5% by weight in water at 60°C.

[0028] As used herein, the term "oil-soluble" means a material having a solubility of at least 0.1 wt. % at 50°C in the core of interest.

[0029] As used herein, the term "oil dispersible" means a material that is dispersible at least 0.1 wt. % in the core of interest at 50°C without visible agglomerates.

[0030] As used herein, "delivery particle," "particle," "encapsulate," "microcapsule," and "capsule" are used interchangeably unless otherwise indicated. As used herein, these terms typically refer to core / shell delivery particles. "Shell" and "wall" are also used interchangeably to refer to the shell of a core / shell delivery particle. Summary of the invention

[0031] The present invention teaches a capsule shell polymer material comprising an oil-soluble crosslinking agent and a modified chitosan polymer. The oil-soluble crosslinking agent may be selected from difunctional or polyfunctional isocyanates, acrylates, methacrylates or acid chlorides. Chitosan has a free amine structure. The modified chitosan polymer according to the present invention comprises a combination of a natural chitosan polymer and a modifying compound, which can form a CN covalent bond with the amine structure of chitosan (particularly a primary amine or a secondary amine). The modifying compound may be selected from an epoxide compound, an aldehyde compound or an α, β-unsaturated compound. Epoxides, aldehyde compounds or α, β-unsaturated compounds may be anionic, cationic or nonionic. The modifying compound may contain an acidic group, a hydroxyl group or a quaternary ammonium group. The α, β-unsaturated compound may be selected from acrylates, alkyl acrylates, α, β-unsaturated esters, acrylic acid, acrylamide, vinyl ketones, vinyl sulfones, vinyl phosphonates, acrylonitrile derivatives or mixtures thereof. It was found that the modified chitosan polymer according to the present invention is soluble at a pH greater than 6.0, even greater than 8.0, even further greater than 10.0.

[0032] Advantageously, the surface charge of the cross-linked chitosan capsules can be modified and customized before, during or after the capsule shell is formed. This is achieved by selecting the modifying compound and the timing of adding the modifying compound. It can be added to the emulsion or the aqueous phase. In particular, when the modifying compound is selected to have a cationic group or an anionic group, it results in an enhanced surface charge of the capsule shell.

[0033] The present invention teaches a method of forming a population of delivery particles comprising a core comprising a benefit agent and an oil phase and a shell surrounding the core, wherein the shell comprises the reaction product of at least one modified chitosan and at least one polyisocyanate.

[0034] The method of the present invention comprises forming an aqueous phase by dissolving chitosan and a modifying compound in an aqueous acidic medium having a pH of 6.5 or less and a temperature of at least 25° C. After modifying the chitosan with the modifying compound, the pH of the aqueous phase containing the modified chitosan solution can be adjusted to greater than 6.5, or even greater than 7, or even greater than 9 as desired.

[0035] The method step also includes forming an oil phase, including combining at least one benefit agent and at least one polyisocyanate, optionally with added oil. The emulsion is formed by mixing the oil phase into an excess of an aqueous phase under high shear agitation, thereby forming droplets of the oil phase and the benefit agent, the droplets being dispersed in the aqueous phase.

[0036] A water-soluble or water-dispersible modifying compound is added to the emulsion or aqueous phase at room temperature or elevated temperature. The modifying compound can be added during the emulsification process (e.g. after grinding) or added thereafter at elevated temperature. The modifying compound contains a cationic group, an anionic group or a nonionic group, typically selected from one or more acidic or quaternary ammonium functional groups. In the method of the present invention, the modifying compound (i.e., an epoxide, an aldehyde or an α,β-unsaturated compound) reacts with the free amine structural part of the chitosan.

[0037] Optionally, the pH of the emulsion is adjusted to a pH of 4 or higher, or even a pH of 6, or even 8, or even a basicity of 8-10 or higher. The emulsion is heated to at least 40°C for a time sufficient to form a shell at the interface of the droplet with the aqueous phase, the shell surrounding the core. The delivery particles formed according to the method of the present invention, particularly when the modifying compound has a cationic group or anionic group, result in the shell of the delivery particles having a surface charge. In some embodiments, such surface charged delivery particles have a zeta potential of 150 mV or less at pH 4.5.

[0038] The modifying compound that can be used in the method of the present invention is selected from epoxides, aldehydes or α, β-unsaturated compounds, containing acidic groups, hydroxyl groups and quaternary ammonium groups. The α, β-unsaturated compound is selected from acrylates, alkyl acrylates, α, β-unsaturated esters, acrylic acid, acrylamide, vinyl ketone, vinyl sulfone, vinyl phosphonate, and acrylonitrile. Specific examples of the modifying compound include [2-(acryloyloxy)ethyl]trimethylammonium salt, (3-acrylamidopropyl)trimethylammonium salt, 2-carboxyethyl acrylate, acrylic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-sulfopropyl acrylate, acidic acrylate oligomers, glycidyl trimethylammonium salt or a combination thereof.

[0039] The delivery particle has a modified chitosan content of at least 18 wt % or even at least 21 wt % based on the weight of the shell.

[0040] The polyisocyanate that can be used in the method of forming the polymer shell is selected from the following: polyisocyanurates of toluene diisocyanate, trimethylolpropane adducts of toluene diisocyanate, trimethylolpropane adducts of xylylene diisocyanate, 2,2'-methylene diphenyl diisocyanate, 4,4'-methylene diphenyl diisocyanate, 2,4'-methylene diphenyl diisocyanate, [diisocyanato(phenyl)methyl]benzene, toluene diisocyanate, tetramethylxylidine diisocyanate, naphthalene-1,5-diisocyanate, 1,4-phenylene diisocyanate, 1,3-diisocyanatobenzene, their derivatives and their combinations.

[0041] In one embodiment, the invention described herein teaches a method of forming a population of delivery particles comprising a core and a shell surrounding the core, the core comprising a beneficial agent and an oil phase, wherein the shell comprises the reaction product of at least one modified chitosan and at least one polyisocyanate, the modified chitosan containing a cationic group, anionic group, or nonionic group covalently bonded to the modified chitosan, the method comprising dissolving the chitosan into an aqueous phase having a pH of at least 6.5 or less, the chitosan having an amine moiety. Combined into the aqueous phase is a modifying compound containing a reactive group that can form a CN covalent bond with the amine moiety of the chitosan.

[0042] The temperature of the aqueous phase is adjusted to 25°C or higher, thereby forming the modified chitosan. Optionally, the pH of the modified chitosan solution is adjusted to pH 6.0 or higher. The modifying compound is covalently bound to the primary or secondary amine moiety of the chitosan through a CN bond and helps to maintain the modified chitosan dissolved in the aqueous phase even at high pH.

[0043] An oil phase is provided which comprises dissolving together at least one benefit agent comprising an oil and at least one polyisocyanate, optionally with a second oil.

[0044] The emulsion is formed by mixing the oil phase into the water phase under high shear agitation to form droplets of the oil phase and benefit agent dispersed in the water phase. The emulsion is heated to at least 40°C for a time sufficient to form a shell at the interface of the droplets and the water phase, the shell surrounding the core.

[0045] In an embodiment, the present invention teaches a composition comprising a core-shell delivery particle, the core comprising a beneficial agent, the shell comprising a polymer comprising a reaction product of a modified chitosan and a polyisocyanate. The modified chitosan comprises the reaction product of chitosan and a modifying compound. The core comprises a beneficial agent and optionally an oil. The modifying compound is selected from epoxides, aldehydes, α, β-unsaturated compounds, which are cationic, anionic or nonionic, and preferably the modifying compound contains an acidic group, a hydroxyl group or a quaternary ammonium group. The α, β-unsaturated compound is selected from acrylates, alkyl acrylates, α, β-unsaturated esters, acrylic acid, acrylamide, vinyl ketones, vinyl sulfones, vinyl phosphonates, and acrylonitrile. Specific examples of modifying compounds include [2-(acryloyloxy)ethyl]trimethylammonium salt, (3-acrylamidopropyl)trimethylammonium salt, 2-carboxyethyl acrylate, acrylic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-sulfopropyl acrylate, acidic acrylate oligomers, glycidyltrimethylammonium salt, or combinations thereof. In an embodiment, at least 21% by weight of the shell consists of modified chitosan, and the shell degrades by at least 40% when tested according to test method OECD 301B.

[0046] In an embodiment, the shell comprises 1-25% by weight of the core-shell delivery particle. When tested according to test method OECD 301B, the shell degrades by at least 40% after at least 60 days, or in some embodiments even after at least 28 days. The core-shell delivery particle has a core to shell ratio of up to 99:1, or even 99.5:0.5 by weight.

[0047] The benefit agent can be selected from the following: fragrances, flavors, agricultural actives, phase change materials, essential oils, lubricants, colorants, preservatives, antimicrobial actives, antifungal actives, herbicides, antiviral actives, preservative actives, antioxidants, biologically active agents, deodorants, emollients, humectants, exfoliants, UV absorbers, corrosion inhibitors, silicone oils, waxes, bleaching particles, fabric conditioners, malodor reducing agents, dyes, fluorescent whitening agents, antiperspirant actives and mixtures thereof.

[0048] The median particle size of the core-shell delivery particles is 1-200 microns, and the microcapsules are either cationic or anionic.

[0049] In embodiments, the delivery particles from the compositions and methods of the invention have a surface charge due to charged domains or charged side groups. The surface charge of the shell is most effectively achieved when the modifying compound has a cationic group or an anionic group. In a particular example, the delivery particle has a zeta potential of 150 mV or less at a pH of 4.5. See, e.g., herein Figure 1 As shown in the examples, the present invention enables the tailoring of zeta potential. The present invention achieves a reduction or moderation of zeta potential under the pH conditions used, resulting in a more controllable encapsulate that is usefully less prone to agglomeration and more compatible with the matrix in end-use applications.

[0050] In some embodiments, the shell degrades by at least 60% of its mass after at least 60 days when tested according to test method OECD 301B.

[0051] The present invention describes a composition and method of forming a population of delivery particles comprising a core and a shell surrounding the core, the method comprising hydrolyzing chitosan by dissolving or dispersing in an acidic medium having a pH of 6.5 or less and a temperature of at least 25°C. An aqueous phase of the hydrolyzed or acid-treated chitosan is formed by the above method. The chitosan is further modified by reacting with an epoxide, an aldehyde or an α,β-unsaturated compound. Unlike other methods that rely on chitosan, the present invention uses modified chitosan to form a novel multifunctional nucleophile. The modified chitosan is further reacted with a multifunctional electrophile.

[0052] In addition, the oil phase is formed by dissolving or dispersing at least one beneficial agent and at least one multifunctional electrophile (e.g., polyisocyanate) into the oil phase. The beneficial agent itself can generally be an oil of the oil phase, wherein the polyisocyanate and the beneficial agent are dissolved together, or optionally dissolved together with the added oil. The emulsion is formed by mixing the aqueous phase and the oil phase into an excess of the aqueous phase under high shear stirring to form droplets of the oil phase and the beneficial agent, which are dispersed in the aqueous phase, wherein the droplets constitute the core of the core-shell delivery particle. Optionally, the pH of the emulsion can be adjusted within the range of pH 3 to pH 10 or above. A modifying compound comprising an epoxide, an aldehyde or an α,β-unsaturated compound (containing an acidic group, a hydroxyl group or a quaternary ammonium group) is added to the emulsion or aqueous phase.

[0053] The emulsion is then cured by heating to at least 40°C, or even at least 60°C for a time sufficient to form a shell at the interface of the droplets with the aqueous phase. The shell is a polymeric material comprising the reaction product of a polyisocyanate and a modified chitosan, which surrounds the droplets of the oil phase and the benefit agent. For many applications, the target droplet size is 0.1 to 100 microns, or even 0.5 to 50 microns. Optionally, curing can also be achieved by actinic radiation (addition of a UV initiator).

[0054] In another embodiment, in order to dissolve or disperse chitosan, chitosan is treated by hydrolysis at a pH of less than 6.5 (e.g., pH from pH 3 to pH 6) and a temperature of at least 25°C, or even at least 60°C, or even at least 80°C. The hydrolysis time (depending on pH and temperature) may be short, but more typically will be at least one hour, or even at least 24 hours. Chitosan is deacetylated to at least 50%, or even at least 75%, or even at least 80%, or even at least 85%, or even at least 92%. Desirably, the average size of chitosan is 600 kilodaltons (kDa) or less. Chitosan is acid-treated or hydrolyzed, and the expressions "acid-treated" or "hydrolyzed" are used interchangeably herein. More importantly, chitosan is modified by reacting with a modifying compound comprising an epoxide, an aldehyde, or an α,β-unsaturated compound. The shell formed is the reaction product of polyurea and polyisocyanate (including any of isocyanate monomers, oligomers or prepolymers) with modified chitosan. The delivery particle population may comprise an aqueous slurry, or alternatively may be sprayed onto a substrate, or alternatively spray dried, thereby producing a polyurea-chitosan shell with further chitosan deposited on the surface of the formed delivery particles. Unreacted chitosan in the aqueous slurry, if not decanted, may form additional chitosan deposited on the surface of the formed microcapsules.

[0055] In one embodiment, the delivery particles are dried and broken when dry, thereby releasing the core. This embodiment can be used for cleaning agents with fragrance delivery or agricultural products with beneficial agents (e.g., agricultural active agents). Dry-burst (dry-pop) type capsules (which break when dry) are formed by controlling reaction conditions such as controlling the curing time and controlling the temperature to produce capsules with thinner walls. Higher curing temperatures and longer curing times can promote higher crosslinking density and enhanced brittleness. Thinner walls (e.g., from 0.1 nanometers to about 300 nanometers) tend to make them brittle when dry. Even in the dry-burst embodiment, the capsules of the present invention also show lower leakage and better retention of the core in the capsule slurry pre-drying.

[0056] In some embodiments, the modified chitosan in the polyurea shell may range from 18 wt %, or from 21 wt % up to 85 wt % or even 90 wt % of the total shell compared to the amount of electrophile (eg, polyisocyanate).

[0057] In a particular embodiment, the process of the invention makes possible a polyurea shell of core-shell microcapsules with modified chitosan in the polyurea shell, wherein (compared to the amount of polyisocyanate) 18 wt.-% or even higher, more particularly 21 wt.-% to 90 wt.-%, or even 21 wt.-% to 85 wt.-%, or even 21 wt.-% to 75 wt.-%, or 21 wt.-% to 55 wt.-% of the total shell is modified chitosan.

[0058] In an alternative embodiment, the modified chitosan polyurea capsules of the present invention allow for the formation of a reacted polymer shell having a high proportion of modified chitosan moieties in the polymer. Such high weight percentage proportions of modified chitosan in the modified chitosan polyurea microcapsules enable improved encapsulation systems that were previously unattainable by interfacial encapsulation methods. The methods and compositions of the present invention differ from ionic methods based on coagulation because the polymers of the present invention are covalently crosslinked with the polyurea constituent monomers, oligomers and prepolymers to form the modified chitosan polyurea polymer shell.

[0059] The composition comprises a core-shell microcapsule, the core comprising a beneficial agent, the shell comprising a polyurea resin formed by reacting an isocyanate monomer, oligomer or prepolymer with a modified chitosan. The chitosan is first hydrolyzed in an acidic medium at a pH of 6.5 or less and a temperature of at least 25°C, typically for at least one hour.

[0060] At low pH, the free amines in chitosan are protonated. For the purposes of the present invention, chitosan is intended to encompass monomers, oligomers, prepolymers and their polymers. When chitosan is protonated, the conventional understanding would be that chitosan loses its ability to act as a cross-linking agent. At low pH (generally less than pH 4), chitosan also stops acting as an emulsifier.

[0061] The capsules formed according to the present invention show low leakage at high weight % of modified chitosan to urea (or polyisocyanate) ratios, and such capsules show degradable properties in a relatively short period of time. Additionally, the capsules are compatible with consumer product substrates (e.g., fabric enhancers, laundry detergents, or similar substrates). In addition, the capsules of the present invention show ionic or cationic surface charges. Compared to capsules formed from the same or similar materials under different reaction conditions, the delivery particles according to the present invention are degradable. Small differences in reaction conditions unexpectedly produce encapsulates with significantly different properties. It was found that as the pH of hydrolysis or acid treatment is reduced to less than pH 6.5, or even less than pH 6, and then modified with a modifying compound, degradability increases.

[0062] The chitosan in the capsule forming method of the present invention dissolves or disperses under acidic conditions of pH 6.5 or lower. The modified chitosan can be formed during the first hydrolysis / dissolution stage, or after the hydrolysis stage, by treatment with the modifying compound. The modified chitosan is soluble at pH 4 or above, or even at pH 6.5 or above.

[0063] The delivery particles according to the present invention can be made to have a zeta potential of at most 15 millivolts (mV) at pH 4.5, or even at most 40 mV at pH 4.5, or even at least 60 mV at pH 4.5, or more preferably 150 mV or less at pH 4.5. Such delivery particles can be cationic or anionic and can be used in applications where deposition on some surface is desired. The capsules can be made nonionic or anionic by selecting the modifying compound and the pH.

[0064] In one embodiment, the ratio of isocyanate monomers, oligomers or prepolymers to hydrolyzed chitosan is up to 1:10 by weight. The weight percentage of chitosan in the polyisocyanate shell can be as low as 21% up to 95% of the shell. Based on the total delivery particle weight, the shell can account for at least 5% by weight of the core-shell microcapsules, or even at least 3% by weight, or even at least 1% by weight of the core-shell microcapsules, and up to 30% by weight of the core-shell microcapsules. Chitosan may have a degree of deacetylation of at least 75%, or even at least 85%, or even at least 92%. In some embodiments, the core-shell microcapsules may have a core-shell ratio of up to about 99:1, or even 99.5:0.5 by weight to the shell. The beneficial agent of the core-shell delivery particle can be selected from fragrances, agricultural active agents, phase change materials, and other active agents as described herein. The core-shell delivery particles typically have a median particle size of 1-200 microns. Different particle sizes can be obtained by controlling the droplet size during emulsification. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 is a graph illustrating the zeta potential of delivery particles prepared according to the present invention. DETAILED DESCRIPTION

[0066] The present invention teaches improved polyurea chitosan microcapsules. In the present invention, polyurea microcapsules are successfully prepared by producing an aqueous solution of hydrolyzed or acid-treated chitosan and modifying the chitosan with a modifying compound. The modified chitosan is a nucleophile and is used as a crosslinking agent to form the shell of the core-shell microcapsule by crosslinking with an electrophile.

[0067] In the present invention, the modified compound and chitosan are added to water in a jacketed reactor and at pH 3-6.5 (adjusted using acid (e.g., concentrated HCl). The modified compound and chitosan can also be added to water in a jacketed reactor at high pH (e.g., pH greater than 6.5, or even greater than 8, without pH adjustment). The chitosan mixture is heated to an elevated temperature (e.g., 85°C) within 60 minutes, and then kept at this temperature for a sufficient time to achieve modification of the chitosan with the modified compound. The modified chitosan solution is then cooled to 25°C.

[0068] Modified chitosan can be prepared from chitosan (e.g., hydrolyzed chitosan or dispersed chitosan in solution) by treatment with a modifying compound. Chitosan is further modified by reaction with an epoxide, an aldehyde, or an α,β-unsaturated compound. Unlike other methods that rely on chitosan, the present invention uses modified chitosan to form a novel multifunctional nucleophile. The modified chitosan is further reacted with a multifunctional electrophile.

[0069] The modifying compound used to modify chitosan can be selected from: epoxides, such as glycidyl trimethylammonium salt, glycidyl isopropyl ether, glycidyl methacrylate, furfuryl glycidyl ether, glycidol, 1,4-butanediol diglycidyl ether, 2-ethylhexyl glycidyl ether, (3-glycidyloxypropyl) trimethoxysilane, poly (ethylene glycol) diglycidyl ether, trimethylolpropane triglycidyl ether; or aldehydes, such as glutaraldehyde, alginate aldehyde (Alginate Aldehyde); or α,β-unsaturated compounds, such as acrylic acid, acrylic acid salts, maleic acid, vinylsulfonic acid, 2-carboxyethyl acrylate, 2-(2-oxo-1-imidazolidinyl)ethyl methacrylate, 2-(2-oxo-1-imidazolidinyl)ethyl methacrylamide, (2-(acryloyloxy)ethyl)trimethylammonium salt, (3-(methacryloylamino)propyl)trimethylammonium salt, N,N-dialkylaminoalkyl acrylate, N,N-dialkylaminoalkyl acrylamide, (3-acrylamidopropyl)trimethylammonium salt, 3-sulfopropyl acrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid and its salts, quaternized vinylimidazole, diallyldialkylammonium salt, vinylamine.

[0070] The oil phase is prepared by dissolving an electrophile (e.g., an isocyanate such as a trimer of xylene diisocyanate (XDI) or a polymer of methylene diphenyl diisocyanate (MDI)) in oil at 25°C. A diluent (e.g., isopropyl myristate) can be used to adjust the hydrophilicity of the oil phase. The oil phase is then added to the aqueous phase and ground at high speed to obtain the target size. The emulsion is then cured in one or more heating steps, such as heating to 40°C in 30 minutes and maintaining at 40°C for 60 minutes. The time and temperature are approximately. The temperature and time are selected to be sufficient to form and cure the shell at the interface of the oil phase droplets and the aqueous continuous phase. For example, the emulsion is heated to 85°C in 60 minutes and then maintained at 85°C for 360 minutes to cure the capsules. The slurry is then cooled to room temperature. Optionally, the same modifying compound or a different modifying compound is added to the emulsion instead to further modify the chitosan.

[0071] For the purposes of the present invention, the electrophiles that can be used in the present invention are understood to be polyisocyanates such as isocyanate monomers, isocyanate oligomers, isocyanate prepolymers, or dimers or trimers of aliphatic or aromatic isocyanates. Available polyisocyanates contain two or more isocyanate (-NCO) groups. These polyisocyanate electrophiles can be aromatic, aliphatic, linear, branched or cyclic. All such electrophiles, whether monomers, prepolymers, oligomers, or dimers or trimers of aliphatic or aromatic isocyanates are intended to be encompassed in the term "polyisocyanate" herein.

[0072] Polyisocyanates are aliphatic or aromatic monomers, oligomers or prepolymers, which can be used with two or more isocyanate functional groups. Polyisocyanates can be selected from aromatic toluene diisocyanate and derivatives thereof (for wall formation of encapsulates), or aliphatic monomers, oligomers or prepolymers, such as hexamethylene diisocyanate and dimer or trimer thereof, or 3,3,5-trimethyl-5-isocyanatomethyl-1-isocyanatocyclohexane tetramethylene diisocyanate. Polyisocyanates can be selected from 1,3-diisocyanato-2-methylbenzene, hydrogenated MDI, bis(4-isocyanatocyclohexyl)methane, dicyclohexylmethane-4,4'-diisocyanate and their oligomers and prepolymers. This list is illustrative and is not intended to limit the polyisocyanates available in the present invention.

[0073] The polyisocyanates useful in the present invention include isocyanate monomers, oligomers or prepolymers having at least two isocyanate groups, or dimers or trimers thereof. Optimized crosslinking can be achieved with polyisocyanates having at least three functional groups.

[0074] Electrophiles useful in the present invention include polyisocyanates. For the purposes of the present invention, polyisocyanates are understood to include any polyisocyanate having at least two isocyanate groups and containing aliphatic or aromatic moieties in monomers, oligomers or prepolymers. Aromatic polyisocyanates are understood to be polyisocyanates containing at least one aromatic moiety. If aromatic, the aromatic moiety may contain phenyl, toluyl, xylyl, naphthyl or diphenyl moieties, more preferably toluyl or xylyl moieties. For the purposes of the present invention, aromatic polyisocyanates may include diisocyanate derivatives, such as biuret and polyisocyanurate. When aromatic, the polyisocyanate may be, but is not limited to, methylene diphenyl diisocyanate, toluene diisocyanate, tetramethylxylidine diisocyanate, polyisocyanurates of toluene diisocyanate (which may be referred to under the trade name RC is commercially available from Bayer), trimethylolpropane adduct of toluene diisocyanate (available under the trade name L75 is commercially available from Bayer) or a trimethylolpropane adduct of naphthalene-1,5-diisocyanate and phenylene diisocyanate or xylylene diisocyanate (available under the trade name D-110N is commercially available from Mitsui Chemicals).

[0075] As aliphatic polyisocyanates are understood to be polyisocyanates that do not contain any aromatic moieties. Aromatic polyisocyanates are understood to be polyisocyanates that contain at least one aromatic moiety. Aromatic polyisocyanates are preferred, however, aliphatic polyisocyanates and blends thereof are useful. Aliphatic polyisocyanates include trimers of hexamethylene diisocyanate, trimers of isophorone diisocyanate, trimethylolpropane adducts of hexamethylene diisocyanate (available from Mitsui Chemicals) or biuret of hexamethylene diisocyanate (available under the trade name N100 is commercially available from Bayer).

[0076] The electrophile need not be limited to polyisocyanates. The electrophile may comprise monomers, oligomers and prepolymers having an electrophilic moiety, and such an electrophilic moiety may comprise any of formyl, keto, carboxyl, isocyanate, carboxylate, acyl halide, amide carboxylic anhydride, alkyl halide, epoxide, sulfonyl halide, chlorophosphate, β-unsaturated carbonyl, α, β-unsaturated nitrile, trifluoromethanesulfonate, p-toluenesulfonate and α, β-unsaturated methanesulfonyl.

[0077] Suitable multifunctional electrophiles may include glutaraldehyde, succinic dialdehyde, glyoxal, glyoxyl trimer, paraformaldehyde, bis(dimethyl)acetal, bis(diethyl)acetal, polymeric dialdehydes such as oxidized starch, low molecular weight difunctional aldehydes, 1,3-propane dialdehyde, 1,4-butane dialdehyde, 1,5-pentane dialdehyde, or 1,6-hexane.

[0078] The capsule shell may also be strengthened using additional co-crosslinkers such as multifunctional amines and / or polyamines, for example diethylenetriamine (DETA), polyethyleneimine and polyethyleneamine.

[0079] core

[0080] The delivery particles of the present invention include beneficial agents, which include one or more compositions intended to be encapsulated. Beneficial agents are selected from many different materials, such as chromogens and dyes, flavoring agents, spices, sweeteners, fragrances, oils, fats, pigments, cleaning oils, medicines, medicinal oils, perfume oils, mold inhibitors, antimicrobial agents, adhesives, phase change materials, odorants, fertilizers, nutrients and herbicides: as an illustration and not as a limitation. Beneficial agent and oil constitute the core. The core can be liquid or solid. For a core that is solid at ambient temperature, the wall material can be usefully wrapped with less than the entire core for some applications, such as the availability of the agglomerate core in applications is desirable. Such purposes can include odor release, cleaning compositions, emollients, cosmetic delivery, etc. When the microcapsule core is a phase change material, uses may include such encapsulated materials in mattresses, pillows, bedding, textiles, athletic equipment, medical devices, building products, construction products, HVAC, renewable energy, apparel, athletic surfaces, electronics, automotive, aviation, footwear, beauty care, laundry, and solar energy.

[0081] The core constitutes the material that is delivered particle encapsulated. Typically, particularly when the core material is a liquid material, the core material and the composition of the inner wall forming the microcapsule or one or more combinations of the solvent for a beneficial agent or a distribution modifier. If the core material can play the role of an oil solvent in the capsule, such as serving as a solvent or carrier of a wall-forming material or a beneficial agent, the core material can be made to become the primary material to be encapsulated, or if the carrier itself is a beneficial agent, it can be the entire material to be encapsulated. However, often, the beneficial agent is the 0.01-99 weight percent of the capsule internal content, preferably the 0.01-about 65 weight % of the capsule internal content, and more preferably the 0.1-about 45 weight % of the capsule internal content. For some applications, even if only traces, the core material can also be effective.

[0082] When the benefit agent itself is not sufficient to act as an oil phase or solvent, particularly for wall-forming materials, the oil phase may comprise a suitable carrier and / or solvent. In this sense, the oil is optional, as the benefit agent itself may sometimes be an oil. These carriers or solvents are typically oils, preferably having a boiling point greater than about 80° C. and having low volatility and being non-flammable. Although not limited thereto, they preferably comprise one or more esters (preferably with a chain length of up to 18 carbon atoms or even up to 42 carbon atoms) and / or triglycerides such as esters of C6-C12 fatty acids and glycerol. Exemplary carriers and solvents include, but are not limited to, ethyl diphenylmethane; isopropyl diphenylethane; butyl diphenylethane; benzyl xylene; alkyl biphenyls, such as propyl biphenyl and butyl biphenyl; dialkyl phthalates, such as dibutyl phthalate, dioctyl phthalate, dinonyl phthalate, and ditridecyl phthalate; 2,2,4-trimethyl-1,3-pentanediol diisobutyrate; alkyl benzenes, such as dodecylbenzene; alkyl or aralkyl benzoates, such as benzyl benzoate; diaryl ethers; di(aralkyl) ethers and aryl aralkyl ethers; ethers, such as diphenyl ether , dibenzyl ether and phenylbenzyl ether; liquid higher alkyl ketones (having at least 9 carbon atoms); alkyl or aralkyl benzoates, such as benzyl benzoate; alkylated naphthalenes, such as dipropylnaphthalene; partially hydrogenated terphenyls; high boiling point straight or branched chain hydrocarbons; alkylaryl hydrocarbons, such as toluene; vegetable oils and other crop oils, such as rapeseed oil, soybean oil, corn oil, sunflower oil, cottonseed oil, lemon oil, olive oil and pine oil; methyl esters of fatty acids derived from the transesterification of vegetable oils and other crop oils, methyl esters of oleic acid, esters of vegetable oils, such as soybean methyl esters, straight chain paraffin aliphatic hydrocarbons and mixtures of the foregoing.

[0083] Useful benefit agents include fragrance raw materials such as alcohols, ketones, aldehydes, esters, ethers, nitriles, olefins, fragrances, fragrance solubilizers, essential oils, phase change materials, lubricants, colorants, coolants, preservatives, antimicrobial or antifungal actives, herbicides, antiviral actives, preservative actives, antioxidants, bioactives, deodorants, emollients, humectants, exfoliants, UV absorbers, self-repairing compositions, corrosion inhibitors, sunscreens, silicone oils, waxes, hydrocarbons, higher fatty acids, essential oils, lipids, skin coolants, vitamins, sunscreens, antioxidants, glycerin, catalysts, bleaching particles, silica particles, odor reducing agents, dyes, whitening agents, antibacterial actives, antiperspirant actives, cationic polymers, and mixtures thereof. As an illustration and not limitation, phase change materials that can be used as beneficial agents may include paraffin hydrocarbons having 13-28 carbon atoms, various hydrocarbons such as n-octacosane, n-heptacosane, n-hexacosane, n-pentacosane, n-tetracosane, n-tricosane, n-docosane, n-heunesane, n-eicosane, n-nonadecane, octadecane, n-heptadecane, n-hexadecane, n-pentadecane, n-tetradecane, n-tridecane. The phase change material may alternatively optionally further include crystalline materials such as 2,2-dimethyl-1,3-propanediol, 2-hydroxymethyl-2-methyl-1,3-propanediol, acids (e.g., eicosanoic acid) and esters (e.g., methyl palmitate) of linear or branched hydrocarbons, fatty alcohols, and mixtures thereof.

[0084] Preferably, in the case of a fragrance, the fragrance oil acts as a solvent for the benefit agent and the wall forming material, as illustrated in the Examples herein.

[0085] The present invention enables tailored surface charge of chitosan urea-based delivery particles to be achieved by chemical attachment to surfaces, especially the outer surface of microcapsules, through charged domains or charged side groups of the resulting polymer.

[0086] Optionally, the aqueous phase may include an emulsifier. Non-limiting examples of emulsifiers include the following water-soluble salts: alkyl sulfates, alkyl ether sulfates, alkyl isothiosulfates, alkyl carboxylates, alkyl sulfosuccinates, alkyl succinamates, alkyl sulfates such as sodium lauryl sulfate, alkyl sarcosinates, alkyl derivatives of protein hydrolysates, acyl aspartates, alkyl or alkyl ether or alkyl aryl ether phosphates, sodium lauryl sulfate, phospholipids or lecithin, or stearic acid soaps, sodium stearate, potassium stearate or ammonium stearate, oleate or palmitate, alkyl aryl sulfonates such as sodium dodecylbenzene sulfonate, dialkyl sodium sulfosuccinate, dioctyl sodium sulfosuccinate, dilauryl sodium sulfosuccinate, poly(styrene sulfonate) sodium salt, isobutylene-maleic anhydride copolymer, gum arabic, sodium alginate, carboxymethyl cellulose, cellulose sulfate and pectin, poly(styrene sulfonate), isobutylene-maleic anhydride copolymer, carrageenan, sodium alginate, pectic acid, tragacanth gum, almond gum and agar; semisynthetic polymers such as carboxymethyl cellulose, sulfated cellulose, sulfated methyl cellulose, carboxymethyl starch, phosphorylated starch, lignin sulfonic acid; and synthetic polymers such as maleic anhydride copolymers (including hydrolyzates thereof), polyacrylic acid, polymethacrylic acid, acrylic acid butyl acrylate copolymer or crotonic acid homopolymers and copolymers, vinylbenzenesulfonic acid or 2-acrylamido-2-methylpropanesulfonic acid homopolymers and copolymers, and partial amides or partial esters of these polymers and copolymers, carboxyl-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol and phosphoric acid-modified polyvinyl alcohol, phosphorylated or sulfated tristyrylphenol ethoxylates, palmitamidopropyltrimonium chloride (Varisoft PATC TM, available from Degussa Evonik, Essen, Germany), distearyl ammonium dichloride, cetyltrimethylammonium chloride, quaternary ammonium compounds, fatty amines, aliphatic ammonium halides, alkyldimethylbenzylammonium halides, alkyldimethylethylammonium halides, polyethyleneimine, poly(2-dimethylaminoethyl methacrylate) methyl chloride quaternary salt, poly(l-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate), poly(acrylamide-co-diallyldimethylammonium chloride), poly(allylamine), quaternized poly[bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] and poly(dimethylamine-co-epichlorohydrin-co-ethylenediamine), condensation products of aliphatic amines with alkylene oxides, quaternary poly(s) having long-chain aliphatic groups Ammonium compounds, such as distearyl diammonium chloride, and fatty amines, alkyl dimethyl benzyl ammonium halides, alkyl dimethyl ethyl ammonium halides, polyalkylene glycol ethers, condensation products of alkyl phenols, aliphatic alcohols or fatty acids with alkylene oxides, ethoxylated alkyl phenols, ethoxylated aryl phenols, ethoxylated polyaryl phenols, carboxylates solubilized with polyols, polyvinyl alcohol, polyvinyl acetate, or copolymers of polyvinyl alcohol polyvinyl acetate, polyacrylamide, poly(N-isopropylacrylamide), poly(2-hydroxypropyl methacrylate), poly(-ethyl-2-oxazoline), poly(2-isopropenyl-2-oxazoline-co-methyl methacrylate), poly(methyl vinyl ether), and polyvinyl alcohol-co-ethylene), and cocamidopropyl betaine. Emulsifiers, if used, are typically present in an amount of about 0.1-40% by weight, preferably 0.2 to about 15% by weight, more typically 0.5 to 10% by weight, based on the total weight of the formulation.

[0087] In addition to the beneficial agent, the delivery particle may also encapsulate a partitioning modifier. Non-limiting examples of partitioning modifiers include isopropyl myristate, C4-C 24 Monoesters, diesters and triesters of fatty acids, castor oil, mineral oil, soybean oil, hexadecanoic acid, methyl ester isododecane, isoparaffin oil, polydimethylsiloxane, brominated vegetable oil and combinations thereof. Delivery particles can also have different ratios of distribution modifiers and beneficial agents to prepare different populations of delivery particles that can have different bloom patterns. These populations can also incorporate different fragrance oils to create populations of delivery particles that display different bloom patterns and different odor experiences. US 2011-0268802 discloses other non-limiting examples of delivery particles and distribution modifiers and is incorporated herein by reference.

[0088] In the formation of chitosan delivery particles, the aqueous solution contains residual amounts of hydrolyzed chitosan. This provides the option of dehydrating the delivery particles, for example, by decantation, filtration, centrifugation or other separation techniques. Alternatively, the aqueous slurry of chitosan polyurea delivery particles can be spray dried to form chitosan polyurea delivery particles that are further coated with a layer of residual hydrolyzed chitosan from the aqueous phase.

[0089] In one embodiment, the formed slurry of delivery particles can be further dispersed in additional water, or dispersed with a low concentration of residual overcoating hydrolyzed chitosan, thereby producing chitosan polyurea delivery particles that can be broken apart upon drying, providing an additional release mechanism that can be used in some applications (e.g., fragrance delivery or agricultural actives for targeted delivery).

[0090] In some examples of the method and composition, the delivery particles may be composed of one or more different groups. The composition may have at least two different delivery particle groups, which are different in terms of the exact composition of the fragrance oil and the median particle size and / or the distribution modifier and fragrance oil (PM:PO) weight ratio. In some examples, the composition includes more than two different groups, which are different in terms of the exact composition of the fragrance oil and its burst strength. In some other examples, the delivery particle group may be different in terms of the weight ratio of the distribution modifier and one or more fragrance oils. In some examples, the composition may include a first delivery particle group with a first ratio and a second delivery particle group with a second ratio, the first ratio being 2:3 to 3:2 for the weight ratio of the distribution modifier and the first fragrance oil, and the second ratio being less than 2:3 but greater than 0 for the weight ratio of the distribution modifier and the second fragrance oil.

[0091] In some embodiments, each different delivery particle population can be prepared in a different slurry. For example, a first delivery particle population can be included in a first slurry and a second delivery particle population can be included in a second slurry. It is understood that there is no limit to the number of different slurries used in combination, and the formulator's choice allows for the combination of 3, 10, or 15 different slurries. The first and second delivery particle populations can differ in the exact composition of the fragrance oil and the median particle size and / or PM:PO weight ratio.

[0092] In some embodiments, the composition can be prepared by combining the first and second slurries with at least one auxiliary component, and optionally packaged in a container. In some instances, the first and second delivery particle groups can be prepared in different slurries, and then spray dried to form particulate matter. Different slurries can be combined before spray drying, or spray dried individually and then combined together when in the form of particulate powder. Once in powder form, the first and second delivery particle groups can be combined with auxiliary ingredients to form a composition that can be used as a raw material for manufacturing consumer goods, industrial products, medical products or other commodities. In some instances, at least one delivery particle group is spray dried and combined with a slurry of the second delivery particle group. In some instances, at least one delivery particle group is dried and prepared by spray drying, fluidized bed drying, tray drying or other such drying methods available.

[0093] In some examples, the slurry or dry particulate matter may include one or more auxiliary materials, such as processing aids selected from the following substances: carriers, aggregation inhibiting materials, deposition aids, particle suspension polymers, and mixtures thereof. Non-limiting examples of aggregation inhibiting materials include salts that can have a charge shielding effect around the particles, such as magnesium chloride, calcium chloride, magnesium bromide, magnesium sulfate, and mixtures thereof. Non-limiting examples of particle suspension polymers include polymers such as xanthan gum, carrageenan, guar gum, shellac, alginates, chitosan; cellulosic materials such as carboxymethyl cellulose, hydroxypropyl methyl cellulose, cationically charged cellulosic materials; polyacrylic acid; polyvinyl alcohol; hydrogenated castor oil; ethylene glycol distearate; and mixtures thereof.

[0094] In some embodiments, the slurry may include one or more processing aids selected from water, aggregation inhibiting materials such as divalent salts; particle suspending polymers such as xanthan gum, guar gum, carboxymethyl cellulose.

[0095] In other examples of the present invention, the slurry may include one or more carriers selected from the following: polar solvents, including but not limited to water, ethylene glycol, propylene glycol, polyethylene glycol, glycerin; non-polar solvents, including but not limited to mineral oil, fragrance raw materials, silicone oil, hydrocarbon paraffin oil, and mixtures thereof.

[0096] In some examples, the slurry may include a deposition aid, which may include a polymer selected from the group consisting of: polysaccharides, in one aspect, cationically modified starch and / or cationically modified guar gum; polysiloxanes; polydiallyldimethylammonium halides; copolymers of polydiallyldimethylammonium chloride and polyvinyl pyrrolidone; compositions comprising polyethylene glycol and polyvinyl pyrrolidone; acrylamide; imidazole; imidazolinium halides; polyvinylamine; copolymers of polyvinylamine and N-vinylformamide; polyvinylformamide, polyvinyl alcohol; polyvinyl alcohol crosslinked with boric acid; polyacrylic acid; polyglyceryl ether silicone crosslinked polymers; copolymers of polyacrylic acid, polyacrylate, polyvinylamine and polyvinyl alcohol; oligomers of amines, in one aspect Diethylenetriamine, ethylenediamine, bis(3-aminopropyl)piperazine, N,N-bis-(3-aminopropyl)methylamine, tris(2-aminoethyl)amine and mixtures thereof; polyethyleneimine, derivatized polyethyleneimine, in one aspect ethoxylated polyethyleneimine; polymeric compounds comprising at least two moieties selected from the group consisting of carboxylic acid moieties, amine moieties, hydroxyl moieties and nitrile moieties on the backbone of polybutadiene, polyisoprene, polybutadiene / styrene, polybutadiene / acrylonitrile, carboxyl-terminated polybutadiene / acrylonitrile or combinations thereof; preformed coacervates of anionic surfactants in combination with cationic polymers; polyamines and mixtures thereof.

[0097] In some additional examples used to illustrate the present invention, at least one population of delivery particles can be included in an agglomerate and then combined with a different population of delivery particles and at least one auxiliary material. The agglomerate can include a material selected from the group consisting of silicon dioxide, citric acid, sodium carbonate, sodium sulfate, sodium chloride, and a binder such as sodium silicate, modified cellulose, polyethylene glycol, polyacrylate, polyacrylic acid, zeolite, and mixtures thereof.

[0098] Suitable equipment for use in the methods disclosed herein may include continuous stirred tank reactors, homogenizers, turbine agitators, recirculation pumps, paddle mixers, plow shear mixers, ribbon blenders, longitudinal axis granulators and drum mixers (both in batch and (when applicable) continuous process configurations), spray dryers and extruders. Such equipment can be obtained from Lodige GmbH (Paderborn, Germany), Littleford Day, Inc. (Florence, Kentucky, USA), Forberg AS (Larvik, Norway), Glatt Ingenieurtechnik GmbH (Weimar, Germany), Niro (Soeborg, Denmark), Hosokawa Bepex Corp. (Minneapolis, Minnesota, USA), Arde Barinco (New Jersey, USA).

[0099] In the method of the present invention, chitosan is dissolved or dispersed in water under mixing. Optionally, pH is adjusted to acidic, such as pH 3, 4, 5 or 6. Modified compounds (such as epoxides, aldehydes or α, β-unsaturated compounds) are added to the chitosan in the solution. As an illustration and not limitation, such modified compounds can be α, β-unsaturated types. For example, the modified compound can be selected as [2-(acryloyloxy)ethyl] trimethylammonium salt. Other such salts are also described herein and in the examples. The solution is mixed at an elevated temperature (such as from 65°C, preferably 70°C, or even 90°C) for a time sufficient to achieve formation of modified chitosan.

[0100] The oil phase is prepared by mixing together a benefit agent (e.g., fragrance) with an isocyanate and optionally a partitioning modifier (e.g., isopropyl myristate). The emulsion is formed by adding the oil phase containing the benefit agent (e.g., fragrance) to the aqueous phase under shear to form an emulsion. The emulsion is heated at an elevated temperature (e.g., from 65 to 90° C. or even 95° C.) for a sufficient time to form a shell at the interface of the droplet and the aqueous phase, the shell surrounding the benefit agent, which forms the core of the core-shell delivery particle.

[0101] In the original position variation of this method, chitosan is dissolved or dispersed in water to produce chitosan solution. pH is adjusted to acidity. Oil phase is prepared by mixing benefit agent (e.g., fragrance) with isocyanate and optionally distributing modifier (e.g., isopropyl myristate). Oil phase is added to water under shearing to form an emulsion, the emulsion comprising droplets of oil phase and benefit agent, the droplets being dispersed in the water phase. In an alternative embodiment of this method, chitosan is modified in situ by adding a modified compound to the emulsion.

[0102] A modifying compound (e.g., an epoxide, an aldehyde, or an α,β-unsaturated compound), such as illustrated in Example 8, employing an acid acrylate oligomer as the α,β-unsaturated compound. The modifying compound is added to the emulsion with mixing and heated, for example, from 65°C to 70°C or even to 90°C or even 95°C, for a sufficient time to modify the chitosan in situ and form a shell at the interface of the oil phase droplet and the aqueous phase, which shell surrounds the oil droplet containing the benefit agent.

[0103] In the method of the present invention, chitosan dissolved or dispersed in water is acidified to a pH of 6.5 or less, treated with an acid or hydrolyzed with an acid, and the descriptions of these acid-treated chitosan or hydrolyzed chitosan are understood to be interchangeable herein. The acid-treated or hydrolyzed chitosan is modified with a modifying compound comprising an epoxide, an aldehyde or an α,β-unsaturated compound.

[0104] The modifying compound (e.g., epoxide, aldehyde or α,β-unsaturated compound) is added to the chitosan in solution or, in the in situ variant described above, to the emulsion after the oil phase is added to the water phase. Optionally, the modifying compound may be a second modifying compound added to the emulsion.

[0105] In another optional variation, a redox initiator comprising a persulfate or peroxide may be added to the acid treated or hydrolyzed chitosan. In an in-situ variation, the redox initiator may be added to the emulsion after the oil phase and the aqueous phase are combined under high shear stirring. The redox initiator advantageously depolymerizes the hydrolyzed chitosan or modified chitosan to promote polymer formation of the shell during capsule formation by reducing viscosity. Modification of the chitosan with an epoxide, an aldehyde or an α,β-unsaturated compound is preferably first completed, although the redox initiator (peroxide or persulfate) may be introduced simultaneously with or even before the modified compound. The redox initiator may be selected from ammonium persulfate, sodium persulfate, potassium persulfate, cesium persulfate, benzoyl peroxide and hydrogen peroxide. The ratio of persulfate or peroxide to raw chitosan is 0.01 / 99.99 to 95 / 5 by weight.

[0106] Therefore, for the sake of clarity, there are several variations in the method. First, the acidified chitosan solution can be treated with the modifying compound by adding the modifying compound to the chitosan in solution. Alternatively, the modifying compound can be added to the emulsion. Similarly and independently, an optional redox initiator can be added to the acidified chitosan solution, or to the emulsion in the emulsification step after the addition of the oil phase. The redox initiator can be added before, simultaneously with, or after the modification step using a modifying compound comprising an epoxide, an aldehyde, or an α,β-unsaturated compound.

[0107] Procedure for determining % degradation

[0108] The % degradation was determined by the "OECD Guideline for Testing Chemicals" 301B CO2 Release (Modified Sturm Test), adopted on July 17, 1992. For ease of reference, this test method is referred to herein as Test Method OECD 301B.

[0109] Procedure for determination of free oil

[0110] This method measures the amount of oil in the aqueous phase and uses 1 mg / ml dibutyl phthalate (DBP) / hexane as an internal standard solution.

[0111] Slightly more than 250 mg of DBP was weighed into a small beaker and transferred to a 250 ml container. Rinse the beaker thoroughly. Fill to 250 ml with hexane.

[0112] Sample preparation: About 1.5-2 grams (40 drops) of capsule slurry was weighed into a 20 ml scintillation vial and 10 ml of ISTD solution was added and the cap was tightly closed. After vigorous shaking several times within 30 minutes, the solution was pipetted into an autosampler vial and analyzed by GC.

[0113] Additional details. Instrument: HP5890 GC connected to HP Chem Station software; Column: 5m x 0.32mm id with 1 μm DB-1 liquid phase; Temperature 50 degrees for 1 minute then heated to 320 degrees at 15 degrees / min; Injector: 275°C; Detector: 325°C; 2ul injection.

[0114] Calculation: For both sample and calibration, add the total peak area minus the area of ​​DBP. Calculate mg of free core oil:

[0115]

[0116] Calculate free core oil %

[0117]

[0118] Procedure for determining beneficial agent leakage

[0119] Obtain 2 one gram samples of the benefit agent granule composition. Add 1 gram (Sample 1) of the granule composition to 99 grams of the product base (where the granules will be used). Age the product base (Sample 1) containing the granules at 35°C in a sealed glass jar for 2 weeks. Similarly age another one gram sample (Sample 2).

[0120] After 2 weeks, filtration was used to recover particles of the granular composition from the product matrix (Sample 1) and from the granular composition (Sample 2). Each granular sample was treated with a solvent that would extract all of the beneficial agent from each sample particle. The solvent containing the beneficial agent from each sample was injected into a gas chromatograph and the peak areas were integrated to determine the total amount of beneficial agent extracted from each sample.

[0121] The beneficial agent leakage percentage is determined by calculating the difference obtained by subtracting the total amount of beneficial agent extracted from Sample 1 from the total amount of beneficial agent extracted from Sample 2, expressed as a percentage of the total amount of beneficial agent extracted from Sample 2, as shown in the following formula:

[0122]

[0123] Procedure for qualitative measurement of delivery particle compatibility in detergent matrices

[0124] The compatibility of delivery particles in detergent matrix is ​​measured by visual inspection of the mixture of delivery particles and detergent matrix in glass jar. Use overhead mixer (overhead mixer) to stir for at least one minute to homogenize the slurry containing delivery particles. Then under mixing, the homogenized slurry is added to the laundry detergent matrix, such as heavy-duty detergent matrix, with a ratio of 1:40 (e.g., 1g slurry in 40g matrix). Use overhead mixer to mix the above mixture at 350rpm for at least 15 minutes. Stop mixing and let the mixture stand for 5 minutes and then check. Visually inspect the mixture with the naked eye and under an optical microscope to detect any aggregate in the mixture. If any aggregate is observed with the naked eye or an aggregate greater than 100 microns is observed under an optical microscope, it is determined that the delivery particles are incompatible with the detergent matrix.

[0125] like Figure 1 The polyurea capsules prepared with chitosan are shown to exhibit a positive zeta potential. Such capsules have an improved deposition efficiency on fabrics.

[0126] All percentages and ratios are calculated by weight unless otherwise indicated. All percentages and ratios are calculated based on the total composition unless otherwise indicated.

[0127] It should be understood that each maximum numerical limit given throughout this specification includes each lower numerical limit, as if such lower numerical limits are explicitly written in this article. Each minimum numerical limit given throughout this specification will include each higher numerical limit, as if such higher numerical limits are explicitly written in this article. Each numerical range given throughout this specification will include each narrower numerical range that falls within such a wider numerical range, as if all such narrower numerical ranges are explicitly written in this article.

[0128] In the following examples, the abbreviations correspond to the materials listed in Table 1.

[0129] Table 1

[0130]

[0131]

[0132] Example

[0133] Comparative Example 1. Polyurea capsules with unmodified chitosan

[0134] A chitosan stock solution was prepared by dispersing 39.60 g of Chitoclear in 840.4 g of deionized water while mixing in a jacketed reactor. The pH of the chitosan dispersion was then adjusted to 3.87 using 17.90 g of concentrated HCl under stirring. The temperature of the chitosan solution was then increased to 85° C. over 60 minutes and then maintained at 85° C. for 2 hours to hydrolyze the chitosan. After the hydrolysis step, the temperature was then reduced to 25° C. over a period of 90 minutes. The pH of the hydrolyzed chitosan solution was 3.97.

[0135] The aqueous phase was prepared by mixing 426.30 g of the above chitosan stock solution and 6.70 g of 5% PVA540 solution in a jacketed reactor. The oil phase was prepared by mixing 146.63 g of perfume and 36.66 g of isopropyl myristate with 4.00 g of Takenate D-110N at room temperature. The oil phase was added to the aqueous phase under high shear grinding to obtain an emulsion with a desired particle size. The emulsion was heated to 40° C. in 30 minutes and then kept at 40° C. for 60 minutes. The emulsion was then heated to 85° C. in 60 minutes and maintained at this temperature for 6 hours while mixing. The median particle size of the formed capsules was 8.05 microns. The formed capsules had a one-week leakage of 20.78%. The prepared slurry was shown to aggregate in a heavy-duty liquid detergent matrix.

[0136] Embodiments of the invention

[0137] Example 1: Cross-linked chitosan delivery particles pre-modified with [2-(acryloyloxy)ethyl]trimethylammonium chloride

[0138] Modified chitosan solution was prepared by dispersing 40.92 g chitosan powder in 792.00 water at 70° C. The pH of the above mixture was adjusted to 4.91 using 9.79 g glacial acetic acid. Then 46.36 g 80% [2-(acryloyloxy)ethyl]trimethylammonium chloride solution was added to the above chitosan solution and mixed at 70° C. for 12 hours to obtain [2-(acryloyloxy)ethyl]trimethylammonium chloride modified chitosan solution. The pH of the modified chitosan solution obtained was 4.05.

[0139] The aqueous phase was prepared by weighing 255.8 g of [2-(acryloyloxy)ethyl]trimethylammonium chloride modified chitosan solution in a jacketed reactor at 25 °C.

[0140] An oil phase was prepared by mixing 87.98 g of fragrance, 2.40 g of Takenate D110 and 22.00 g of isopropyl myristate in a beaker at 25°C.

[0141] The oil phase is added to the water phase under high shear at room temperature for a period of time to obtain an emulsion.

[0142] The emulsion was then heated to 40°C within 30 minutes and then held at 40°C for 60 minutes. The emulsion was then heated to 85°C within 60 minutes and held for 6 hours to solidify the wall. The emulsion was then cooled down to 25°C within 90 minutes. The median particle size of the obtained capsules was 12.27 microns. The QFO and 1-week leakage of the capsule slurry were 7.69% and 68.59%, respectively. The prepared slurry showed no aggregation in a heavy-duty liquid detergent matrix.

[0143] Example 2: Cross-linked chitosan pre-modified with [2-(acryloyloxy)ethyl]trimethylammonium chloride and pH adjustment Delivery particles

[0144] Example 2 was prepared according to the procedure of Example 1, except that the pH of the aqueous phase was adjusted to 6.8 using sodium hydroxide solution. The aqueous phase remained transparent after the pH adjustment. The median particle size of the obtained capsules was 36.44 microns. The QFO and 1-week leakage of the capsule slurry were 0.11% and 0.99%, respectively. The prepared slurry showed no aggregation in a heavy duty liquid detergent matrix.

[0145] Example 3: Using [2-(acryloyloxy)ethyl]trimethylammonium chloride and pH adjustment with the second modified compound - SR444 pre-modified cross-linked chitosan delivery particles

[0146] The modified chitosan solution was prepared according to the procedure in Example 1. The pH of the modified chitosan solution was 4.10. The aqueous phase contained the modified chitosan solution, wherein the pH was adjusted to 9.35 with sodium hydroxide solution.

[0147] An emulsion was prepared according to Example 1 and then the emulsion was heated to 70°C and then the second modified compound SR444 was added to the emulsion at 70°C. The emulsion was then heated to 90°C over 60 minutes and held for another 8 hours and then cooled down to 25°C to complete the curing process. The median particle size of the obtained capsules was 23.63 microns. The QFO and 1 week leakage of the capsule slurry were 0.35% and 6.19%, respectively. The prepared slurry showed no aggregation in a heavy duty liquid detergent matrix.

[0148] Example 4: Cross-linked chitosan delivery particles pre-modified with CD9055 (acidic acrylate oligomer)

[0149] The modified chitosan solution was prepared by dispersing 42.11 g of chitosan powder in 840.00 g of water at 70° C. Then 42.11 g of CD9055 (acidic acrylate oligomer) was added to the above chitosan mixture and mixed at 70° C. for 12 hours to obtain a CD9055 modified chitosan solution. The pH of the obtained modified chitosan solution was 4.08.

[0150] The aqueous phase was prepared by weighing 328.00 g of CD9055 modified chitosan solution in a jacketed reactor at 25 °C.

[0151] An oil phase was prepared by mixing 112.82 g perfume, 3.08 g Takenate D110 and 28.21 g isopropyl myristate in a beaker at 25°C.

[0152] The oil phase is added to the water phase under high shear at room temperature for a period of time to obtain an emulsion.

[0153] The emulsion was then heated to 40°C within 30 minutes and then held at 40°C for 60 minutes. The emulsion was then heated to 85°C within 60 minutes and held for 6 hours to solidify the wall. The emulsion was then cooled down to 25°C within 90 minutes. The median particle size of the obtained capsules was 37.74 microns. The QFO and 1-week leakage of the capsule slurry were 0.83% and 41.46%, respectively.

[0154] Example 5: Delivery of cross-linked chitosan particles pre-modified with CD9055 (acidic acrylate oligomer) and pH adjustment grain

[0155] The aqueous phase was prepared by weighing 255.78 g of CD9055 modified chitosan solution from Example 4 in a jacketed reactor at 25° C. The pH of the aqueous phase was then adjusted to 8.23 ​​using 21.5% caustic soda solution. The aqueous phase remained transparent after the pH adjustment.

[0156] An oil phase was prepared by mixing 87.98 g of fragrance, 2.40 g of Takenate D110 and 22.00 g of isopropyl myristate in a beaker at 25°C.

[0157] The oil phase is added to the water phase under high shear at room temperature for a period of time to obtain an emulsion.

[0158] The emulsion was then heated to 40°C within 30 minutes and then held at 40°C for 60 minutes. The emulsion was then heated to 85°C within 60 minutes and held for 6 hours to solidify the wall. The emulsion was then cooled down to 25°C within 90 minutes. The median particle size of the obtained capsules was 25.72 microns. The QFO and 1-week leakage of the capsule slurry were 0.28% and 6.95%, respectively. The prepared slurry showed no aggregation in a heavy-duty liquid detergent matrix.

[0159] Example 6: Crosslinking pre-modified with CD9055 (acidic acrylate oligomer) and second modifying compound SR444 Chitosan delivery particles

[0160] Modified chitosan solution was prepared by dispersing 42.11 g chitosan in 840 g water at 70° C. The pH of the above mixture was adjusted to 4.86 using 11.26 g glacial acetic acid. Then 35.85 g CD9055 was added to the above chitosan solution and mixed at 70° C. for 12 hours to obtain CD9055 modified chitosan solution. The pH of the modified chitosan solution obtained was 3.90.

[0161] The aqueous phase was prepared by adding 266.70 g of CD9055 modified chitosan solution to the jacketed reactor.

[0162] An oil phase was prepared by mixing 99.71 g perfume, 2.72 g Takenate D110 and 24.93 g isopropyl myristate in a beaker at 25°C.

[0163] The oil phase is added to the water phase under high shear at room temperature for a period of time to obtain an emulsion.

[0164] The obtained emulsion was then heated to 70°C and then the second crosslinker SR444 was added to the emulsion at 70°C. The emulsion was then heated to 90°C within 60 minutes and maintained for another 8 hours and then cooled down to 25°C to complete the curing process. The median particle size of the obtained capsules was 27.52 microns. The QFO and 1-week leakage of the capsule slurry were 0.10% and 34.40%, respectively.

[0165] Example 7: Crosslinked chitosan pre-modified with CD9055 (acidic acrylate oligomer) and a second modifying compound Sugar delivery particles

[0166] The modified chitosan solution was prepared by dispersing 42.11 g of chitosan powder in 840.00 g of water at 70° C. Then 42.11 g of CD9055 (acidic acrylate oligomer) was added to the above chitosan mixture and mixed at 70° C. for 12 hours to obtain a CD9055 modified chitosan solution. The pH of the obtained modified chitosan solution was 4.08.

[0167] The aqueous phase was prepared by weighing 255.78 g of CD9055 modified chitosan solution in a jacketed reactor at 25 °C.

[0168] An oil phase was prepared by mixing 87.98 g of fragrance, 2.40 g of Takenate D110 and 22.00 g of isopropyl myristate in a beaker at 25°C.

[0169] The oil phase was added to the water phase under high shear at room temperature for a period of time to obtain an emulsion. The pH of the emulsion was adjusted to 9.07 using sodium hydroxide solution at 40°C.

[0170] The emulsion was then heated to 40°C within 30 minutes and the pH of the emulsion was adjusted to 9.07 using sodium hydroxide solution. The emulsion was then held at 40°C for 60 minutes and then heated to 85°C within 60 minutes and held for 6 hours to solidify the wall. The emulsion was then cooled down to 25°C within 90 minutes. The median particle size of the obtained capsules was 25.95 microns. The QFO and 1-week leakage of the capsule slurry were 0.66% and 24.91%, respectively. The prepared slurry showed no aggregation in a heavy-duty liquid detergent matrix.

[0171] Example 8: Cross-linked chitosan delivery particles modified in situ with CD9055 (acidic acrylate oligomer)

[0172] A chitosan solution was prepared as in Comparative Example 1, but the pH of the chitosan solution was 5.23.

[0173] Aqueous phase was prepared by adding 308.70 g of the above chitosan solution into a jacketed reactor at 25 °C.

[0174] An oil phase was prepared by mixing 102.64 g perfume, 2.80 g Takenate D110 and 25.66 g isopropyl myristate in a beaker at 25°C.

[0175] The oil phase is added to the water phase under high shear at room temperature for a period of time to obtain an emulsion.

[0176] The obtained emulsion was then heated to 70°C, and then the modified compound 10.71g CD9055 was added to the emulsion at 70°C. The emulsion was then heated to 90°C within 60 minutes and maintained for another 8 hours, and then cooled down to 25°C to complete the curing process. The median particle size of the obtained capsules was 30.22 microns. The QFO and 1-week leakage of the capsule slurry were 0.49% and 48.08%, respectively.

[0177] Example 9: Cross-linked chitosan delivery particles modified in situ with [2-(acryloyloxy)ethyl]trimethylammonium chloride grain

[0178] A chitosan solution was prepared as in Comparative Example 1, but the pH of the chitosan solution was 5.23.

[0179] Aqueous phase was prepared by adding 308.70 g of the above chitosan solution into a jacketed reactor at 25 °C.

[0180] An oil phase was prepared by mixing 102.64 g perfume, 2.80 g Takenate D110 and 25.66 g isopropyl myristate in a beaker at 25°C.

[0181] The oil phase is added to the water phase under high shear at room temperature for a period of time to obtain an emulsion.

[0182] The obtained emulsion was then heated to 70°C and then the modified compound 17.92g of 80% [2-(acryloyloxy)ethyl]trimethylammonium chloride solution was added to the emulsion at 70°C. The emulsion was then heated to 90°C within 60 minutes and maintained for another 8 hours and then cooled down to 25°C to complete the curing process. The median particle size of the obtained capsules was 27.84 microns. The QFO and 1-week leakage of the capsule slurry were 0.29% and 4.62%, respectively. The prepared slurry showed no aggregation in a heavy duty liquid detergent matrix.

[0183] Example 10: Cross-linked chitosan delivery particles modified in situ with acrylic acid

[0184] A chitosan stock solution was prepared by dispersing 155.7 g of Chitosan Chitoclear in 3304 g of deionized water while mixing in a jacketed reactor. The pH of the chitosan dispersion was then adjusted to 5.23 using 69.84 g of concentrated HCl under stirring. The temperature of the chitosan solution was then increased to 65°C over 30 minutes, then to 85°C over 30 minutes, then to 95°C over 30 minutes, and then maintained at 95°C for 2 hours to hydrolyze the chitosan ChitoClear. After the hydrolysis step, the temperature was then reduced to 25°C over a period of 90 minutes. The pH of the hydrolyzed chitosan solution was 5.31.

[0185] The water phase was prepared by mixing 433.6 g of the above chitosan stock solution in a jacketed reactor at 25°C. The oil phase was prepared by mixing 128.9 g of spices and 32.2 g of isopropyl myristate with 4.88 g of Takenate D-110N at room temperature. The oil phase was added to the water phase under high shear grinding to obtain an emulsion with a desired particle size. The emulsion was heated to 60°C in 45 minutes and then heated to 95°C in 60 minutes. Once at 95°C, a solution of 2.07 g of acrylic acid, 2.07 g of RO water and 5.08 g of 21.5% NaOH (prepared in an ice bath) was added to the slurry and then kept at 95°C for 360 minutes. The temperature was then reduced to 25°C in 90 minutes. The median particle size of the formed capsules was 30.42 microns.

[0186] Example 11: Cross-linked chitosan delivery particles modified in situ with acrylic acid

[0187] A cross-linked chitosan capsule slurry was prepared as in Example 10, except that a solution of 2.07 g acrylic acid, 2.07 g RO water and 5.08 g 21.5% NaOH (prepared in an ice bath) was replaced with a solution of 8.29 g acrylic acid, 8.29 g RO water and 20.31 g 21.5% NaOH (prepared in an ice bath) once added at 95° C. The median particle size of the formed capsules was 31.25 μm.

[0188] Example 12: Cross-linked chitosan delivery particles modified in situ with the addition of 100 mol% acrylic acid at 25°C

[0189] A cross-linked chitosan capsule slurry was prepared as in Example 10, except that a solution of 8.29 g acrylic acid, 8.29 g RO water and 20.31 g 21.5% NaOH (prepared in an ice bath) was added once an emulsion with the desired particle size was obtained at 25°C instead of a solution of 2.07 g acrylic acid, 2.07 g RO water and 5.08 g 21.5% NaOH at 95°C. The median particle size of the formed capsules was 31.68 microns. The prepared slurry showed no aggregation in a heavy duty liquid detergent matrix.

[0190] Example 13: Cross-linked chitosan delivery particles modified in situ with acrylic acid and SR268

[0191] A cross-linked chitosan capsule slurry was prepared as in Example 10, except that 1.74 g SR268 was also added immediately after adding a solution of 2.07 g acrylic acid, 2.07 g RO water, and 5.08 g 21.5% NaOH at 95° C. The median particle size of the formed capsules was 30.83 microns.

[0192] Example 14: Cross-linked chitosan delivery particles modified in situ with 3-sulfopropyl acrylate potassium salt

[0193] A cross-linked chitosan capsule slurry was prepared the same as in Example 10, except that 6.69 g of 3-sulfopropyl acrylate potassium salt was added once at 95°C instead of a solution of 2.07 g acrylic acid, 2.07 g RO water and 5.08 g 21.5% NaOH. The median particle size of the formed capsules was 30.83 microns. The prepared slurry showed no aggregation in a heavy duty liquid detergent matrix.

[0194] Example 15: Delivery of cross-linked chitosan modified in situ by addition of glycidyltrimethylammonium chloride at 25°C Particles

[0195] A cross-linked chitosan capsule slurry was prepared as in Example 10, except that 10.92 g of 80% glycidyl trimethyl ammonium chloride was added once an emulsion with the desired particle size was obtained at 25° C. instead of adding a solution of 2.07 g acrylic acid, 2.07 g RO water and 5.08 g 21.5% NaOH at 95° C. The median particle size of the formed capsules was 32.98 microns.

[0196] Example 16: Cross-linked chitosan capsules modified in situ by addition of glycidyl trimethyl ammonium chloride at 95°C

[0197] A crosslinked chitosan capsule slurry was prepared as in Example 10 except that 5.46 g of 80% glycidyl trimethyl ammonium chloride was added once at 95° C. instead of a solution of 2.07 g acrylic acid, 2.07 g RO water and 5.08 g 21.5% NaOH. The median particle size of the formed capsules was 30.84 μm.

[0198] Example 17: Delivery of cross-linked chitosan modified in situ by addition of glycidyltrimethylammonium chloride at 25°C Particles.

[0199] A cross-linked chitosan capsule slurry was prepared as in Example 10, except that 5.46 g of 80% glycidyl trimethyl ammonium chloride was added once an emulsion with the desired particle size was obtained at 25° C. instead of adding a solution of 2.07 g acrylic acid, 2.07 g RO water and 5.08 g 21.5% NaOH at 95° C. The median particle size of the formed capsules was 29.61 microns.

[0200] Example 18: Cross-linked chitosan delivery particles modified in situ with neutralized CD9055, SR268 and KPS

[0201] Chitosan stock solution was prepared by dispersing 155.7 g of Chitosan Chitoclear in 3304 g of deionized water while mixing in a jacketed reactor. 1.56 g of potassium persulfate (KPS) was added. The pH of the chitosan dispersion was then adjusted to 5.84 using 57.29 g of concentrated HCl under stirring. The temperature of the chitosan solution was then increased to 65° C. within 30 minutes, then to 85° C. within 30 minutes, then to 95° C. within 30 minutes, and then maintained at 95° C. for 2 hours to hydrolyze the chitosan ChitoClear. After the hydrolysis step, the temperature was then reduced to 25° C. within a period of 90 minutes. The pH of the hydrolyzed chitosan solution was 5.85.

[0202] The aqueous phase was prepared by mixing 390.0 g of the above chitosan stock solution in a jacketed reactor at 25°C. The oil phase was prepared by mixing 115.9 g of fragrance and 29.0 g of isopropyl myristate with 4.40 g of Takenate D-110N at room temperature. The oil phase was added to the aqueous phase under high shear grinding to obtain an emulsion with the desired particle size. The emulsion was heated to 60°C in 45 minutes and then heated to 95°C in 60 minutes. Once at 95°C, a solution of 4.52 g of CD9055, 4.52 g of RO water and 4.97 g of 21.5% NaOH (prepared in an ice bath) was added to the slurry in 1 minute, followed by 4.20 g of SR268 in 1 minute, followed by 180 minutes at 95°C, followed by 1.90 g of potassium persulfate in 1 minute, and then followed by 180 minutes at 95°C. The temperature was then reduced to 25°C in 90 minutes. The median particle size of the formed capsules was 28.44 microns. The prepared slurry showed no aggregation in a heavy duty liquid detergent matrix.

[0203] Example 19: Cross-linked chitosan delivery particles modified with acrylic acid and KPS

[0204] A chitosan stock solution was prepared by dispersing 155.7 g of Chitoclear in 3304 g of deionized water while mixing in a jacketed reactor. 1.56 g of potassium persulfate was added. The pH of the chitosan dispersion was then adjusted to 5.84 using 57.24 g of concentrated HCl under stirring. The temperature of the chitosan solution was then increased to 65°C over 30 minutes, then to 85°C over 30 minutes, then to 95°C over 30 minutes, and then maintained at 95°C for 2 hours to hydrolyze ChitoClear. After the hydrolysis step, the temperature was then reduced to 25°C over a period of 90 minutes. The pH of the hydrolyzed chitosan solution was 5.83.

[0205] The water phase is prepared by mixing 433.6g of the above chitosan stock solution in a jacketed reactor at 25°C. The oil phase is prepared by mixing 129.0g of spices and 32.0g of isopropyl myristate with 4.88g of Takenate D-110N at room temperature. The oil phase is added to the water phase under high shear grinding to obtain an emulsion with a desired particle size. The emulsion is heated to 60°C in 45 minutes and then heated to 95°C in 60 minutes. 30 minutes after reaching 95°C, a solution of 4.16g of acrylic acid, 4.16g of RO water and 8.04g of 21.5% NaOH (prepared in an ice bath) is added to the slurry in 1 minute and then kept at 95°C for 360 minutes. The temperature is then reduced to 25°C in 90 minutes. The median particle size of the formed capsules is 27.86 microns. The prepared slurry shows no aggregation in a heavy-duty liquid detergent matrix.

[0206] Example 20: Cross-linked chitosan delivery particles modified in situ with neutralized CD9055, SR268 and KPS

[0207] A chitosan stock solution was prepared by dispersing 155.7 g of Chitoclear in 3304 g of deionized water while mixing in a jacketed reactor. 1.56 g of potassium persulfate was added. The pH of the chitosan dispersion was then adjusted to 5.84 using 57.37 g of concentrated HCl under stirring. The temperature of the chitosan solution was then increased to 65°C over 30 minutes, then to 85°C over 30 minutes, then to 95°C over 30 minutes, and then maintained at 95°C for 2 hours to hydrolyze ChitoClear. After the hydrolysis step, the temperature was then reduced to 25°C over a period of 90 minutes. The pH of the hydrolyzed chitosan solution was 5.82.

[0208] The aqueous phase was prepared by mixing 432.5 g of the above chitosan stock solution in a jacketed reactor at 25°C. The oil phase was prepared by mixing 110.0 g of the fragrance and 27.3 g of isopropyl myristate with 4.15 g of Takenate D-110N at room temperature. The oil phase was added to the aqueous phase under high shear grinding to obtain an emulsion with the desired particle size. The emulsion was heated to 60°C in 45 minutes and then heated to 95°C in 60 minutes. Once at 95°C, a solution of 9.29 g of CD9055, 9.29 g of RO water, and 10.22 g of 21.5% NaOH (prepared in an ice bath) was added to the slurry in 1 minute, followed by 1.95 g of SR268 in 1 minute, followed by 180 minutes at 95°C, followed by 1.96 g of potassium persulfate in 1 minute, and followed by 180 minutes at 95°C. The temperature was then reduced to 25° C. over 90 minutes. The median particle size of the formed capsules was 30.26 μm.

[0209] Example 21: Cross-linked chitosan delivery particles modified with CD9055, SR268 and KPS

[0210] Modified chitosan solution was prepared by dispersing 42.11 g chitosan powder in 840.00 g water at 70°C. The pH of the chitosan solution was then adjusted to 4.85 using 11.06 g glacial acetic acid. 35.82 g CD9055 (acidic acrylate oligomer) was then added to the above chitosan mixture and mixed at 70°C for 12 hours to obtain CD9055 modified chitosan solution. The pH of the modified chitosan solution obtained was 3.86.

[0211] 266.7 g of the above modified chitosan solution was weighed in a jacketed reactor at 25°C, and then the pH of the chitosan solution was adjusted to 9.27 using 18.84 g of 21.5% caustic soda solution at room temperature. A potassium persulfate solution containing 2.06 g of potassium persulfate and 50 g of water was then added to the chitosan solution to form an aqueous phase.

[0212] An oil phase was prepared by mixing 99.71 g perfume, 2.72 g Takenate D110 and 24.93 g isopropyl myristate in a beaker at 25°C.

[0213] The oil phase is added to the water phase under high shear at room temperature for a period of time to obtain an emulsion.

[0214] The emulsion was heated to 70°C and then 13 g of SR268 was added to the solution. The emulsion was then heated to 90°C in 60 minutes and held for 8 hours to solidify the wall. The emulsion was then cooled down to 25°C in 90 minutes. The median particle size of the obtained capsules (in the form of a water slurry) was 43.94 microns. The QFO and 1 week leakage of the capsule slurry were 0.13% and 3.27%, respectively. The prepared slurry showed no aggregation in a heavy duty liquid detergent matrix.

[0215] Aqueous slurries of the core-shell particles of the present invention also allow for more concentrated slurries to be stable in a variety of matrices. The composition made into a slurry may contain less than about 25% water, preferably less than about 20% water, more preferably less than about 15% water, even more preferably less than about 12% water, even more preferably less than about 10% water, even more preferably less than about 5% water by weight of water relative to the weight of the core-shell particles in the composition.

[0216] The percentage degradation is measured according to the OECD Guidelines for Testing Chemicals, Test Method OECD 301 B. A copy is available at www.oecd-ilibrary.org.

[0217] The shell of the composition according to the invention has the following % degradation when tested according to test method OECD 301 B: at least 40% degradation after at least 28 days and at least 60% degradation after at least 60 days.

[0218] Unless otherwise indicated herein or clearly contradictory to the context, the use of the singular "a", "an" is intended to cover both the singular and the plural. The terms "comprising", "having", "including" and "containing" are interpreted as open terms. All references cited herein (including publications, patent applications and patents) are incorporated herein by reference. Any description of some embodiments as "preferred" embodiments and other descriptions of embodiments, features or ranges as preferred, or these are preferred suggestions are not considered to be limiting. The invention is considered to include embodiments that are currently considered less preferred and can be described as such herein. Unless otherwise indicated herein or clearly contradictory to the context, all methods described herein can be performed in any suitable order. Any and all examples or exemplary language (e.g., "for example") provided herein are intended to illustrate the present invention, rather than to impose limitations on the scope of the invention. Any statements herein about the attributes or benefits of the present invention or preferred embodiments are not intended to be limiting. The present invention includes all modifications and equivalents of the subject matter recorded herein as permitted by applicable law. In addition, unless otherwise indicated herein or clearly contradictory to the context, the present invention includes any combination of the above-described elements with all possible variations thereof. The description herein of any reference or patent, even if identified as "prior art," is not intended to constitute an admission that such reference or patent is available as prior art to the present invention. Unclaimed language should not be construed as limiting the scope of the present invention. Any statement or suggestion herein that some feature constitutes a component of the claimed invention is not intended to be limiting unless reflected in the appended claims.

Claims

1. A method of forming a population of delivery particles comprising a core and a shell surrounding the core, The core comprises a benefit agent, wherein the shell comprises the reaction product of at least one modified chitosan and at least one electrophile, The method comprises: forming an aqueous phase by dissolving or dispersing chitosan having free amine moieties in an aqueous acidic medium having a pH of 6.5 or less and a temperature of at least 25° C.; forming an oil phase comprising combining at least one benefit agent and at least one electrophile, preferably a polyisocyanate, optionally with added oil; forming an emulsion by: mixing the oil phase into an excess of the water phase under high shear agitation to form droplets of the oil phase and the benefit agent, the droplets being dispersed in the water phase; adding a water-soluble or water-dispersible modifying compound to the emulsion or the aqueous phase, wherein the modifying compound comprises one or more of an epoxide, an aldehyde or an α,β-unsaturated compound, and the modifying compound reacts with the free amine structure of the chitosan; optionally adjusting the pH of the emulsion to a pH of 4 or greater; and The emulsion is heated to at least 40°C for a time sufficient to form a shell at the interface of the droplet and the aqueous phase, the shell surrounding the core.

2. The method of claim 1, wherein the delivery particle has a zeta potential of 150 mV or less at pH 4.

5. 3 . The method according to claim 1 , wherein the modifying compound is selected from the group consisting of epoxides, aldehydes, and α,β-unsaturated compounds, and the modifying compound contains a cationic group or an anionic group.

4. The method according to claim 1, wherein the modifying compound is an α,β-unsaturated compound selected from the group consisting of acrylates, alkyl acrylates, α,β-unsaturated esters, acrylic acid, acrylamide, vinyl ketone, vinyl sulfone, vinyl phosphonate, and acrylonitrile.

5. The method of claim 3, wherein the modifying compound is [2-(acryloyloxy)ethyl]trimethylammonium salt, (3-acrylamidopropyl)trimethylammonium salt, 2-carboxyethyl acrylate, acrylic acid, 2-acrylamido-2-methyl-1-propane sulfonic acid, 2-acrylamido-2-methyl-1-propane sulfonate, glycidyl trimethylammonium salt, or a combination thereof.

6. The method according to claim 1, wherein the molar ratio of the modifying compound to the free amine moiety of the chitosan is 0.1%-100%, preferably 10%-90%, more preferably 25%-75%, even more preferably 25%-50%.

7. The method of claim 1, wherein the delivery particle has a modified chitosan content of at least 18 wt% or even at least 21 wt% based on the weight of the shell.

8. The process according to claim 1, wherein a redox initiator comprising a persulfate or a peroxide is additionally added to the emulsion or the aqueous phase.

9. The method of claim 1, wherein the electrophile is a polyisocyanate selected from the group consisting of polyisocyanurates of toluene diisocyanate, trimethylolpropane adducts of toluene diisocyanate, trimethylolpropane adducts of xylylene diisocyanate, 2,4'-methylene diphenyl diisocyanate, [diisocyanato(phenyl)methyl]benzene toluene diisocyanate, tetramethylxylidine diisocyanate, naphthalene-1,5-diisocyanate, 1,4-phenylene diisocyanate, 1,3-diisocyanatobenzene, derivatives thereof, and combinations thereof.

10. A method of forming a population of delivery particles, the delivery particles comprising a core and a shell, the shell surrounding the core, The core comprises a benefit agent and an oil phase, wherein the shell comprises the reaction product of at least one modified chitosan and at least one electrophile, preferably a polyisocyanate, the modified chitosan comprising the reaction product of chitosan and a modifying compound, the modifying compound comprising an epoxide, an aldehyde or an α,β-unsaturated compound, the modifying compound being covalently bonded to the chitosan, the method comprising: dissolving or dispersing chitosan in an aqueous phase, wherein the chitosan has an amine structure, combining at least one of the epoxide, the aldehyde or the α,β-unsaturated compound into the aqueous phase, the modifying compound forming a CN covalent bond with the amine structure of the chitosan, Optionally adjusting the pH of the aqueous phase to pH 3.0 or higher, and adjusting the temperature of the aqueous phase to 25° C. or higher while mixing for a period of time, thereby forming a modified chitosan, including the covalent bonding of the modified compound to the amine structure of the chitosan through a CN bond, and maintaining the modified chitosan dissolved in the aqueous phase, providing an oil phase comprising dissolving together at least one benefit agent comprising an oil and at least one electrophile, preferably a polyisocyanate, optionally with a second oil; forming an emulsion by: mixing the oil phase into the water phase under high shear agitation to form droplets of the oil phase and the benefit agent, the droplets being dispersed in the water phase; The emulsion is heated to at least 40°C for a time sufficient to form the shell at the interface of the droplet and the aqueous phase, the shell surrounding the core. 11 . The method according to claim 10 , wherein the modifying compound is selected from the group consisting of epoxides, aldehydes or α,β-unsaturated compounds, and wherein the modifying compound additionally contains a cationic group or an anionic group.

12. The method according to claim 10, wherein the modifying compound is selected from the group consisting of: an epoxide, an aldehyde, or an α,β-unsaturated compound, additionally containing at least one of a cationic group, an anionic group, or a nonionic group; wherein the cationic group, anionic group or nonionic group is selected from the following: an acidic group, a hydroxyl group, and a quaternary ammonium group; and The α,β-unsaturated compound is selected from the group consisting of acrylates, alkylacrylates, α,β-unsaturated esters, acrylic acid, acrylamide, vinyl ketone, vinyl sulfone, vinyl phosphonate, and acrylonitrile.

13. The method of claim 10, wherein the modifying compound is selected from the group consisting of epoxides, aldehydes, and α,β-unsaturated compounds, wherein the modifying compound additionally contains an acidic group, a hydroxyl group, or a quaternary ammonium group.

14. The method of claim 10, wherein the α,β-unsaturated compound is selected from acrylates, alkyl acrylates, α,β-unsaturated esters, acrylic acid, acrylamide, vinyl ketone, vinyl sulfone, vinyl phosphonate, or acrylonitrile.

15. The method of claim 10, wherein the chitosan is modified with a modifying compound comprising an α,β-unsaturated carbonyl compound.

16. The method according to claim 10, wherein the modifying compound is glycidyl trimethylammonium salt, glycidyl isopropyl ether, glycidyl methacrylate, furfuryl glycidyl ether, glycidol, 1,4-butanediol diglycidyl ether, 2-ethylhexyl glycidyl ether, (3-glycidyloxypropyl) trimethoxysilane, poly (ethylene glycol) diglycidyl ether, trimethylolpropane triglycidyl ether, glutaraldehyde, alginic acid aldehyde, acrylic acid, acrylate, maleic acid, vinyl sulfonic acid, 2-carboxyethyl acrylate, 2-(2-oxo-1-amidite) The invention can be used in combination with quaternary ammonium esters, such as (1,2-dialkylamino)ethyl methacrylate, 2-(2-oxo-1-imidazolidinyl)ethyl methacrylamide, (2-(acryloyloxy)ethyl)trimethylammonium salt, (3-(methacryloylamino)propyl)trimethylammonium salt, N,N-dialkylaminoalkyl acrylate, N,N-dialkylaminoalkyl acrylamide, (3-acrylamidopropyl)trimethylammonium salt, 3-sulfopropyl acrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid and its salts, quaternized vinylimidazole, diallyldialkylammonium salt, vinylamine, or a combination thereof.

17. The method according to claim 10, wherein the molar ratio of the modifying compound to the free amine moiety of the chitosan is 0.1%-99.9%, preferably 10%-90%, more preferably 25%-75%, even more preferably 25%-50%.

18. The method according to claim 10, wherein a redox initiator comprising a persulfate or a peroxide is additionally added to the emulsion or the aqueous phase.

19. The method of claim 10, wherein the electrophile is a polyisocyanate selected from the group consisting of polyisocyanurates of toluene diisocyanate, trimethylolpropane adducts of toluene diisocyanate, trimethylolpropane adducts of xylylene diisocyanate, 2,2'-methylene diphenyl diisocyanate, 4,4'-methylene diphenyl diisocyanate, 2,4'-methylene diphenyl diisocyanate, [diisocyanato(phenyl)methyl]benzene toluene diisocyanate, tetramethylxylidine diisocyanate, naphthalene-1,5-diisocyanate, 1,4-phenylene diisocyanate, 1,3-diisocyanatobenzene, derivatives thereof, and combinations thereof.

20. A composition comprising a core-shell microcapsule, said core comprising a beneficial agent, said shell comprising a polymer, said polymer comprising the reaction product of a modified chitosan and an electrophile, preferably a polyisocyanate, The modified chitosan comprises a reaction product of chitosan and a modifying compound, The core comprises a benefit agent and optionally an oil, The modifying compound is selected from epoxides, aldehydes or α, β-unsaturated compounds, and further contains at least one of a cationic group, anionic group or nonionic group, wherein the cationic group, anionic group or nonionic group is selected from the following: an acidic group, a hydroxyl group, or a quaternary ammonium group, and the α, β-unsaturated compound is selected from acrylic acid, acrylate, acrylate, alkyl acrylate, α, β-unsaturated ester, maleic acid, vinyl sulfonic acid, 2-carboxyethyl acrylate, 2-(2-oxo-1-imidazolidinyl)ethyl methacrylate, 2-(2-oxo-1 -imidazolidinyl)ethyl methacrylamide, (2-(acryloyloxy)ethyl)trimethylammonium salt, (3-(methacryloylamino)propyl)trimethylammonium salt, N,N-dialkylaminoalkyl acrylate, N,N-dialkylaminoalkyl acrylamide, (3-acrylamidopropyl)trimethylammonium salt, acrylamide, acrylamide salt, 3-sulfopropyl acrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid and its salts, quaternized vinylimidazole, diallyldialkylammonium salt, vinylamine, vinyl ketone, vinyl sulfone, vinyl phosphonate, and acrylonitrile; wherein at least 21% by weight of said shell consists of said modified chitosan; wherein the shell degrades by at least 40% when tested according to test method OECD 301 B.

21. The composition of claim 20, wherein the shell comprises 1-25% by weight of the core-shell microcapsule.

22. The composition according to claim 20, wherein the molar ratio of the modifying compound to the free amine moiety of the chitosan is 0.1%-99.9%, preferably 10%-90%, more preferably 25%-75%, even more preferably 25%-50%.

23. The composition of claim 20, wherein the electrophile is selected from the group consisting of polyisocyanurates of toluene diisocyanate, trimethylolpropane adducts of toluene diisocyanate, trimethylolpropane adducts of xylylene diisocyanate, 2,2'-methylene diphenyl diisocyanate, 4,4'-methylene diphenyl diisocyanate, 2,4'-methylene diphenyl diisocyanate, toluene diisocyanate, tetramethylxylidine diisocyanate, naphthalene-1,5-diisocyanate, 1,4-phenylene diisocyanate, 1,3-diisocyanatobenzene, and combinations thereof.

24. The composition of claim 20, wherein the core-shell microcapsule has a core to shell ratio of up to 99:1, or even 99.5:0.5 by weight.

25. The composition of claim 20 comprising an aqueous slurry of a population of core-shell microcapsules, the slurry comprising less than about 25% water, preferably less than about 20% water, more preferably less than about 15% water, even more preferably less than about 12% water, even more preferably less than about 10% water, even more preferably less than about 5% water by weight of water relative to the weight of core-shell microcapsules in the composition.

26. The composition of claim 20, wherein the benefit agent is selected from the group consisting of fragrances, flavors, agricultural actives, phase change materials, essential oils, lubricants, colorants, preservatives, antimicrobial actives, antifungal actives, herbicides, antiviral actives, preservative actives, antioxidants, bioactives, deodorants, emollients, humectants, exfoliants, UV absorbers, corrosion inhibitors, silicone oils, waxes, bleaching particles, fabric conditioners, malodor reducing agents, dyes, fluorescent whitening agents, antiperspirant actives, and mixtures thereof.

27. The composition of claim 20, wherein the core-shell delivery particles have a median particle size of 1-200 microns.

28. The composition of claim 20, wherein the microcapsules are cationic or anionic.

29. The composition of claim 20, wherein the microcapsule has a zeta potential of 150 mV or less at pH 4.

5.

30. The composition of claim 20, wherein the shell degrades by at least 60% of its mass after at least 60 days when tested according to test method OECD 301B.

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