CN119698325A

CN119698325A - Microcapsules and their encapsulation

Info

Publication number: CN119698325A
Application number: CN202380056551.7A
Authority: CN
Inventors: A·萨哈; V·帕提尔; A·曼卡尔; K·瓦泽
Original assignee: Situikolka Co ltd
Current assignee: Situikolka Co ltd
Priority date: 2022-07-25
Filing date: 2023-06-01
Publication date: 2025-03-25
Also published as: MX2025000955A; EP4561743A1; JP2025527409A; WO2024023598A1

Abstract

The present invention relates to microcapsules based on a polymer shell and a lipophilic active core material with improved thermal stability.

Description

Microcapsule and encapsulation thereof

Technical Field

The present invention relates to microcapsules based on formaldehyde-free polymer shells and lipophilic active core materials, which have improved thermal stability. Microcapsules with crosslinked acrylate vinyl copolymer shells impart the benefit of high thermal stability such that the microcapsule shell breaks only at temperatures above 250 ℃ and the shell prevents core leakage for long periods of time at higher temperatures (120 ℃ for 30 minutes). This makes the microcapsules suitable for applications at high temperatures as well as applications under ambient conditions. The invention also relates to a method of manufacturing microcapsules.

Background

Most leave-on and rinse-off formulations (including cosmetic formulations) contain fragrances or perfumes to impart a pleasant odor to the formulation itself or to the surface to which the formulation is applied (whether textile, skin or hair). Fragrances or perfumes are generally compounds that are sensitive to various chemicals as well as oxidation and thus require encapsulation. Thus, undesired interactions with other ingredients of the formulation (such as surfactants) can lead to a change in flavor. In addition, fragrances or perfumes are mostly highly volatile. Thus, a substantial portion of the amount of fragrance initially added to the formulation volatilizes prior to the application time and the remaining amount of fragrance actually applied to the treated surface also evaporates in a short period of time. To overcome these problems, it has been proposed to incorporate fragrances or perfumes in microcapsules into formulations. These microcapsules enable the relatively uniform distribution of the valuable fragrance or perfume in the formulation without having to expose it to other ingredients during storage. Proper selection of the shell of the capsule also enables effects to be achieved in this way, such as delayed release or release on demand upon friction or release at higher temperatures.

WO2014/189980A1 describes an encapsulated benefit agent population having a population diameter coefficient of variation of 6% to 50, preferably 8% to 35, more preferably 12% to about 25, the encapsulated benefit agent population comprising an encapsulated benefit agent having an average diameter of 3 microns to 300 microns, preferably 5 microns to 240 microns, more preferably 10 microns to 120 microns, the encapsulated benefit agent comprising a core and a shell encapsulating the core, the shell comprising a polymer, preferably a film forming polymer, the shell having a thickness of 0.5 microns to 15 microns, preferably 1 micron to 8 microns, more preferably 1.5 microns to 6 microns and a coefficient of variation of shell thickness of 2% to 30, preferably 4% to 25, more preferably 6% to 20. Also included is an encapsulated benefit agent population according to claim 1, wherein the shell material comprises polyvinyl alcohol, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl acetate phthalate, vinyl acetate neodecanoate copolymer, vinyl acetate ethylene copolymer, vinyl acetate crotonate neodecanoate copolymer, vinyl acetate crotonic acid copolymer, vinyl acetate butyl maleate copolymer, cellulose acetate phthalate, ethylcellulose, hydroxypropyl methylcellulose phthalate, cellulose acetate butyrate, vinyl pyrrolidone vinyl acetate copolymer, poly (styrene-maleic acid) isobutyl ester, poly (styrene-butadiene copolymer), poly (styrene-acrylic acid copolymer), and mixtures thereof, but does not involve microcapsules having high thermal stability.

WO2012/162742 (also disclosed as AU2011902127, EP2714817, CN104053729, US9339781B2, AU2012262664B2, NZ618219 or CA 2837897) teaches a method of preparing an aqueous dispersion of a polymer encapsulated particulate material, the method comprising providing a dispersion of the particulate material in a continuous aqueous phase, the dispersion comprising an ethylenically unsaturated monomer and a stabilizer for the particulate material, and polymerizing the ethylenically unsaturated monomer by non-living free radical polymerization to form a polymer encapsulating the particulate material, thereby providing an aqueous dispersion of the polymer encapsulated particulate material, wherein the polymerization of the ethylenically unsaturated monomer comprises (a) polymerizing a monomer composition comprising an ionizable ethylenically unsaturated monomer to form a base-responsive water-swellable non-reactive polymer layer encapsulating the particulate material, and (B) polymerizing the monomer composition comprising the non-ionizable ethylenically unsaturated monomer to form an extensible, water-and base-permeable non-reactive polymer layer encapsulating the base-responsive water-swellable polymer layer.

WO2012/162742 also teaches a polymer encapsulating the resulting particulate material, which is encapsulated by a base-responsive water-swellable inactive polymer layer comprising polymerized residues of ionizable ethylenically unsaturated monomers, wherein the base-responsive water-swellable inactive polymer layer is encapsulated by an extensible, water and base-permeable inactive polymer layer comprising polymerized residues of non-ionizable ethylenically unsaturated monomers, but does not relate to microcapsules with high thermal stability.

WO2017004339 (A1) teaches a consumer product comprising a composition comprising an adjunct material, a first population of microcapsules having a first median volume-weighted particle size and comprising microcapsules comprising a partitioning modifier and a first perfume oil in a first weight ratio, and a second population of microcapsules having a second median volume-weighted particle size and comprising microcapsules comprising a partitioning modifier and a second perfume oil in a second weight ratio, wherein the first and second weight ratios are different, and/or the first and second median volume-weighted particle sizes are different, wherein the composition is a fabric and home care composition, thus relating to consumer products having two different populations of microcapsules and not teaching microcapsules having high thermal stability.

WO2005/002719 teaches a method of preparing microcapsules comprising the steps of:

(a) Mixing a free radically polymerizable and ethylenically unsaturated monomer, an emulsifier, a superhydrophobic material, an initiator, and deionized water to prepare a miniemulsion, and (b) polymerizing the miniemulsion to prepare microcapsules, but not to impart high thermal stability to the microcapsules.

US2012076843 (A1) teaches a microcapsule comprising a capsule core and a capsule wall, the microcapsule being obtainable by a process comprising free radical polymerization of an oil-in-water emulsion comprising, based on the total weight of the monomers, from 30 to 90% by weight of one or more monomers (monomer I) selected from C1-C24 alkyl esters of acrylic and/or methacrylic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, from 10 to 70% by weight of one or more ethylenically unsaturated crosslinkers (monomer II) based on the total weight of the monomers, wherein at least 10% by weight based on the total weight of the monomers I, II and III is a highly branched polymeric crosslinker, from 0 to 30% by weight based on the total weight of the monomers of one or more monounsaturated monomers (monomer III) different from monomer I and a hydrophobic core material. It does not teach microcapsules having high thermal stability.

WO2019/121736 teaches an encapsulated perfume composition comprising at least one core-shell microcapsule suspended in a suspension medium, wherein the at least one core-shell microcapsule comprises a core comprising at least one perfume ingredient, and a shell surrounding or at least partially surrounding the core, wherein the shell comprises a thermosetting resin formed by the reaction of a shell-forming material selected from monomers, prepolymers and/or precondensates, and wherein the encapsulated perfume composition comprises a polymeric stabilizer that is the reaction product of a polymeric surfactant and a silane comprising functional groups capable of forming covalent bonds with the shell. But does not disclose the thermal stability of the microcapsule composition according to this prior art.

WO2020190689 (also disclosed as US2020/0315931 A1) teaches a population of microcapsules comprising a capsule core and a capsule shell (the capsule shell being hydrolysable) made by an oil-in-water microencapsulation process comprising a) dispersing a polymeric emulsifier and optionally an initiator in an aqueous phase, b) dispersing in one or more oil phases i) an initiator and a core material, ii) a first multifunctional (meth) acrylate monomer having on average more than one ester group and a hydrophilicity index of less than 20, iii) a second multifunctional (meth) acrylate monomer comprising a hydrophilic multifunctional polar monomer having a hydrophilicity index of at least 20, and said second multifunctional polar monomer comprising 50% or less of the capsule shell, wherein the first and second multifunctional (meth) acrylate monomers together comprise more than 80% by weight of the capsule shell, iv) an acidic (meth) acrylate monomer or at least one oil-soluble or oil-dispersible simple acid or both, the acidic (meth) acrylate monomer having one or more carboxyl groups and one or more sulfonic acid groups and optionally an aqueous phase of 0% to 50% of the polyester, and an aqueous phase of the polyester, and the polyester, agitating the aqueous phase or more than 0% or more, forming an aliphatic polyester emulsion, the emulsion comprising droplets of a core material and an oil phase monomer dispersed in an aqueous phase, d) activating one or more initiators by heat or actinic radiation to react the monomers and optionally an aliphatic polyester to form a polymeric capsule shell surrounding the emulsion droplets. Thus, this prior art teaches multifunctional (meth) acrylate monomers as shell wall variants, which do not involve vinyl acetate monomers, but rather polyvinylpyrrolidone together with butyl acrylate participate in the formation of microcapsule shells, which do not involve capsules with increased thermal stability.

CN109453724a discloses a method for preparing sustained release microcapsules having a plurality of cores inside. The preparation method comprises the steps of dispersing a suspension mixed with an acrylic ester polymer, a volatile organic solvent, a liquid essence and porous starch into an aqueous solution of a colloid protecting agent through mechanical stirring to form an oil-in-water system, then decompressing to remove the volatile organic solvent in the oil-in-water system, carrying out interfacial phase separation on the acrylic ester polymer, the liquid essence and the porous starch to form an acrylic ester polymer microcapsule with the liquid essence and the porous starch wrapped inside, further adding an ethylene glycol dimethacrylate prepolymer, and carrying out heating and curing to obtain the crosslinked acrylic ester polymer essence microcapsule with a plurality of cores inside, namely, a sustained release microcapsule with a plurality of cores inside. The method is simple to operate and high in preparation efficiency, the wrapped essence can be gradually released, the fragrance is durable, and the method can be widely applied to the fields of cosmetics, household articles or personal care products and functional materials.

US20170211019 (also disclosed as WO 2017/132101A1, JP 6651637B2 or EP3408363 A1) teaches a composition comprising, based on total composition weight, a) from about 0.01% to about 1% of a polymeric material comprising a first polymer and a second polymer; the first polymer is derived from the polymerization of about 5 to about 100 mole percent of a cationic vinyl addition monomer, about 0 to about 95 mole percent of a nonionic vinyl addition monomer, about 50ppm to about 1,950ppm of a cross-linking agent comprising two or more ethylenic functionalities, about 0ppm to about 10,000ppm of a chain transfer agent, the second polymer is derived from the polymerization of about 5 to about 100 mole percent of a cationic vinyl addition monomer, about 0 to about 95 mole percent of a nonionic vinyl addition monomer, about 0ppm to about 45ppm of a cross-linking agent comprising two or more ethylenic functionalities, about 0ppm to about 10,000ppm of a chain transfer agent, B) about 0% to about 35% of a cationic quaternary ammonium salt fabric softener active material, the iodine value of the parent fatty acyl compound or acid from which the alkyl or alkenyl chain is derived is about 5 to about 60, and c) the perfume microcapsule population comprises a microcapsule wall material comprising one or more polyacrylate polymers and the home care product. The polymer is derived by comprising (iii) an anionic monomer selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and monomers performing sulfonic or phosphonic acid functions, such as 2-acrylamido 2-methylpropanesulfonic acid and salts thereof. The perfume microcapsules comprise microcapsule wall materials that contain predominantly quaternary cationic vinyl addition monomers, nor does they teach any improved microcapsule thermal stability.

WO 2017123965 (also disclosed as US2019/0054440 A1、AU2017207981B2、EP3402674、CN108778730B、BR112018014242、US20190054440、JP2019505375(JP 6938514B2)、CA3011107、IN201817026022、MX2018008726) teaches a microcapsule comprising i. a lipophilic core material, and ii. a microcapsule shell, wherein the microcapsule shell is formed by oil-in-water emulsion polymerization of a monomer mixture consisting essentially of (a) from greater than 70 to about 99 weight percent of at least one multifunctional ethylenically unsaturated monomer, (b) from about 1 to about 30 weight percent of at least one unsaturated carboxylic acid monomer or ester thereof, and (c) from about 0 to about 30 weight percent of at least one vinyl monomer.

WO2017040759 (also disclosed as CA2980193, CN107530672, AU2016317844, EP 3344382) teaches an aqueous slurry composition comprising an aqueous medium having dispersed therein microcapsules of an oil-containing medium, wherein the microcapsules of the oil-containing medium comprise an ionic acrylate copolymer shell encapsulating the oil medium. Thus, only microcapsules based on acrylic polymers are taught, not any shell structure based on a methyl (acrylic) -vinyl acetate copolymer, to obtain thermally stable microcapsules by a unique process.

EP2397120B2 (also disclosed as WO 2011/158962, ES2597980, US9464263B2, CN102946843, BR112012032063, JP2013530253, MX 344969) teaches a liquid consumer product having a density in the range of 0.900g/cm ³ to 1.400g/cm ³, preferably 0.900g/cm ³ to 1.250g/cm ³, and comprising core-shell microcapsules, wherein:

-the microcapsule shell is formaldehyde free and made of a starting material such that 50% -100% by weight of the material has a density equal to or less than 1.05g/cm ³;

the microcapsule core contains a perfume composition comprising:

a) 20-100 wt% of at least one cyclic aromatic material having a density greater than 0.950

G/cm ³ and ClogP in the range of 1.00 to 6.00;

b) 0 to 50% by weight of at least one oil-soluble organic compound having a density of greater than 0.950

g/cm³;

C) 0-80 wt% of at least one material selected from cyclic perfume ingredients having a density equal to or less than 0.950g/cm ³ and acyclic perfume ingredients having a density that may be greater than or less than 0.950g/cm ³;

Wherein the sum of a), b) and c) equals 100%, wherein the weight ratio of core material to shell material is in the range of 50:1 to 1:1, and wherein the starting material comprises at least 50 wt%, preferably at least 60 wt% of one or more (meth) acrylates, wherein the dosage of microcapsules in the liquid consumer product is in the range of 0.01 to 10 wt%, preferably 0.05 to 2.5 wt%, more preferably 0.1 to 1.25 wt% of the liquid product composition, and thus teaches selecting the density based on the shell wall material to encapsulate the selected perfume, wherein the shell material does not involve any poly ((meth) acrylate-vinyl acetate copolymer) that produces heat stable crosslinked microcapsules based on the selected polymerization process.

WO2014032920A1、EP2890486B1、CN104755162B、KR1020150052046、RU2015111081、BR112015004387、ID2016/05358、RU0002639909、JP2015535858、CA2882427、1199/CHENP/2015;MX2015002649、JP2017105791; Microcapsules are taught comprising a core of hydrophobic material composed of at least one perfume and a microcapsule shell obtained by suspension polymerization of (a) one or more C1-C24 alkyl esters of (meth) acrylic acid (monomer a), (B) one or more difunctional or polyfunctional monomers (monomer B) and (C) optionally, one or more other ethylenically unsaturated monomers (monomer C), wherein the shear rate at which the emulsion is prepared falls within the range of 150 to 500rpm, the agitation time for preparing the emulsion falls within the range of 15 minutes to 180 minutes, and an anchor stirrer blade or MIG stirrer is used to prepare the emulsion, however it does not teach any thermally stable microcapsules obtainable from the particular addition of vinyl acetate monomers by avoiding the shear rates mentioned in this prior art.

WO2017/004339、US20170002301、CA2989002、CN107835681、EP3316854B1、JP2018522976、PL3316854、IN201717045571、MX364218、JP2020073672; A consumer product comprising a composition is taught comprising an adjunct material, a first population of microcapsules having a first median volume-weighted particle size and comprising microcapsules comprising a partitioning modifier and a first perfume oil in a first weight ratio, and a second population of microcapsules having a second median volume-weighted particle size and comprising microcapsules comprising a partitioning modifier and a second perfume oil in a second weight ratio, wherein the first and second weight ratios are different and/or the first and second median volume-weighted particle sizes are different, wherein the composition is a fabric and home care composition, and thus the prior art does not teach that thermally stable microcapsules can be obtained by avoiding partitioning modifiers and based on only one type of microcapsules having only one perfume type.

While microcapsules encapsulating actives are known in the art, there remains a need to explore microcapsules having lipophilic materials as cores (such as fragrances) that are thermally stable, decompose above 250 ℃, to accommodate high temperature applications including fabric steaming, hair straightening, painting, textile processing, insole making.

Disclosure of Invention

It is therefore an object of the present invention to provide microcapsules with a lipophilic core which are thermally stable as microcapsules such that the shell does not break during application at its higher temperature and thus prevents loss of the lipophilic core and under any mechanical stress the shell breaks to release the core/benefit agent.

It is a further object of the present invention to provide such microcapsules having a lipophilic core containing a liquid active such as a perfume.

It is another object of the present invention to provide such a microcapsule synthesis process which involves the preheating/prepolymerization of the monomer/shell material in the oil phase, which is carried out under a preparation procedure comprising a single polymerization step, i.e. all the reactive monomers are copolymerized together in one step.

Drawings

Figure 1 shows the olfactory performance of the microcapsule composition.

Figure 2 shows the TGA thermogram of the microcapsule composition.

Figure 3 shows an isothermal TGA thermogram of the microcapsule composition.

Fig. 4 shows the olfactory performance of the microcapsule composition after steaming for 3 minutes at 120 ℃.

The present invention relates to a microcapsule comprising a lipophilic core material and a microcapsule shell, wherein the microcapsule shell is formed by oil-in-water emulsion polymerization of a monomer mixture, more than 50% by weight of the monomer mixture consisting of monomers having a density higher than 1.05, the monomer mixture comprising a) more than 30% by weight of one or more ethylenically unsaturated acid monomers, b) one or more monofunctional acrylate and/or methacrylate monomers, c) one or more multifunctional acrylate and/or methacrylate monomers, and d) vinyl acetate monomers, based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are thermally stable at 250 ℃.

In one embodiment, the microcapsules are formaldehyde free.

In one embodiment, the microcapsules are characterized in that the log P value of all monomers contained in the monomer mixture ranges from 0.5 to 4.0.

In one embodiment, the microcapsules are characterized in that the ethylenically unsaturated acid monomer is selected from acrylic acid, methacrylic acid, crotonic acid, 2-carboxyethyl acrylate, glutaconic acid, 3-dimethacrylate, itaconic acid, maleic acid, fumaric acid or a mixture of two or more of said acids.

In one embodiment, the microcapsules are characterized in that the ethylenically unsaturated acid monomer is methacrylic acid.

In one embodiment, the microcapsules are characterized in that the concentration of ethylenically unsaturated acid monomers in the monomer mixture is equal to or less than 45 weight percent based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized in that the concentration of ethylenically unsaturated acid monomers in the monomer mixture is between 30 wt% and 45 wt%, based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized in that the monofunctional acrylate and/or methacrylate monomer is selected from a polymerizable molecule having one ester functional group of the formula:

Wherein the method comprises the steps of

R1=H/CH₃,

R2＝-OH、-(CH₂)_n-OH、O-CH₃、-O-(CH₂)_m-OH、-O-(CH₂)_n–CH₃、

-(O-CH₂-CH₂)_n-OH、-(O-CH₂-CH₂-CH₂)_n-OH、-(O-CH₂-CH₂)_n-O-CH₃、-(O-CH₂-CH₂)_n-O-CH₂-CH₃、-(O-CH₂-CH₂-CH₂)n-O-CH₂-CH₃、-(O-CH₂-CH₂-CH₂)n-O-CH₃、-(O-CH₂-CHR3)_n-CH₃

N=1 to 10, m=2 to 10, and r3=methyl or ethyl.

In one embodiment, the microcapsules are characterized in that the monofunctional acrylate and/or methacrylate monomer is selected from 2-hydroxyethyl methacrylate, poly (ethylene glycol) methacrylate, poly (propylene glycol) methacrylate, 4-hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate or a mixture of two or more of said monomers.

In one embodiment, the microcapsules are characterized in that the monofunctional acrylate and/or methacrylate monomer is hydroxyethyl methacrylate.

In one embodiment, the microcapsules are characterized by a concentration of monofunctional acrylate and/or methacrylate monomers of between 5 and 50 wt% based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized in that the multifunctional acrylate and/or methacrylate monomers are selected from polymerizable molecules having more than one ester functional group.

In one embodiment, the microcapsules are characterized in that the one or more multifunctional acrylate and/or methacrylate monomers are a mixture of two or more of said monomers,

In one embodiment, the microcapsules are characterized in that the multifunctional acrylate and/or methacrylate monomer is selected from ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1, 4-butanediol diacrylate, 1, 4-butanediol dimethacrylate, 1, 6-hexanediol dimethacrylate, glycerol diacrylate, glycerol dimethacrylate, 1, 10-decanediol dimethacrylate, bis [2- (methacryloyloxy) ethyl ] phosphate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, or a mixture of two or more of said monomers.

In one embodiment, the microcapsules are characterized in that the multifunctional acrylate and/or methacrylate monomer is a mixture of two or more of said monomers, each of said monomers comprising less than 30 wt% based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized by a total concentration of multifunctional acrylate and/or methacrylate monomers in the monomer mixture of less than 60 weight percent based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized in that the concentration of the multifunctional acrylate and/or methacrylate monomers in the monomer mixture is between 20 and 50 wt% based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized in that the concentration of vinyl acetate monomer in the monomer mixture is between 0.05 and 15wt% based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized by a) ethylenically unsaturated acid monomers, b) monofunctional acrylate and/or methacrylate monomers, c) multifunctional acrylate and/or methacrylate monomers, and d) vinyl acetate monomers at a concentration of at least 95 weight percent based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized by a) ethylenically unsaturated acid monomers, b) monofunctional acrylate and/or methacrylate monomers, c) multifunctional acrylate and/or methacrylate monomers, and d) vinyl acetate monomers, [ a) +b) +c) +d) ] at a concentration of 100 wt% based on the total weight of the monomer mixture.

In one embodiment, the microcapsules are characterized by a Dv (90) value in the particle size range of 8 to 35 microns.

In one embodiment, the microcapsules are characterized in that the lipophilic core material of the microcapsules has a density equal to or less than 0.95g/cm ³ at 25 ℃ with a combined log P of between 2.5 and 6.0.

In one embodiment, the microcapsule is characterized in that the lipophilic core material of the microcapsule comprises at least 95 wt%, preferably 100 wt%, based on the total weight of the lipophilic core material, of one or more of fragrances, fragrance precursors (profragrances), emollient oils, essential oils, hair benefit agents (hair-benefitting agent), skin benefit agents (skin-benefitting agent), conditioning actives, cosmetic care actives, personal care actives, ultraviolet light absorbers, vitamins, antioxidants, antimicrobial agents, antiviral agents, flavoring agents, deodorants, medicaments, dyes, printing inks, insecticides, microbiocides, agrochemicals, coating materials, anti-aging actives.

In one embodiment, the microcapsule is characterized in that the lipophilic core material of the microcapsule comprises one or more of the following ingredients, fragrances, essential oils, hair benefit agents, skin benefit agents, antimicrobial agents, antiviral agents, anti-malodor agents.

In one embodiment, the microcapsule is characterized by a lipophilic core material weight divided by a microcapsule shell weight of between 15 and 0.2, such as between 15 and 0.33, such as between 15 and 0.4.

An aqueous microcapsule composition comprising water and microcapsules according to claim 1, wherein the water comprises from 35 to 82% by weight of the total weight of the aqueous microcapsule composition.

The invention also relates to an aqueous microcapsule composition comprising microcapsules comprising a lipophilic core material and a microcapsule shell

Wherein the microcapsule shell is formed by oil-in-water emulsion polymerization of a monomer mixture comprising more than 50% by weight of monomers having a density of more than 1.05, said monomer mixture comprising a) more than 30% by weight of one or more ethylenically unsaturated acid monomers, b) one or more monofunctional acrylate and/or methacrylate monomers, c) one or more multifunctional acrylate and/or methacrylate monomers, and d) vinyl acetate monomers, based on the total weight of the monomer mixture, and

Wherein the lipophilic core material comprises from 15 wt% to 45 wt% of the total weight of the aqueous microcapsule composition.

In one embodiment, the aqueous microcapsule composition is characterized in that it comprises one or more emulsifiers, wherein the emulsifiers comprise from 0.05 to 5 weight percent of the total weight of the aqueous microcapsule composition.

In one embodiment, the aqueous microcapsule composition is characterized in that the weight of water, microcapsules and emulsifier comprises at least 90% by weight of the total weight of the aqueous microcapsule composition.

The invention also relates to a method of preparing an aqueous microcapsule composition comprising microcapsules comprising a lipophilic core material and a microcapsule shell

Wherein the lipophilic core material comprises 15 to 45 wt% of the total weight of the aqueous microcapsule composition,

The method comprises the following steps:

1. dissolving the monomer mixture together with an initiator in an oil phase comprising a lipophilic core material, and heating the oil phase to form a prepolymer,

2. The emulsifier is dissolved in the aqueous phase,

3. Emulsifying the oil phase of step1 into the water phase of step 2, and

4. The emulsion from step 3 is heated to form a suspension of core shell microcapsules in water.

In one embodiment, the method for preparing the aqueous microcapsule composition is characterized in that the step of emulsifying the core phase in the aqueous phase is obtained by stirring at 500-1500rpm using a propeller stirrer for up to 12 minutes.

The invention also relates to a non-therapeutic method of use of the microcapsules or aqueous microcapsule compositions as claimed, comprising using the microcapsules to deliver lipophilic core materials of industrial compositions associated with home care products, personal care products, textile products, printing and coating application products, pharmaceutical formulation products, consumer products and agricultural industrial formulation products.

In one embodiment, the non-therapeutic method of use is characterized by mechanical stress and temperature conditions at which the microcapsules are exposed sufficient to disrupt the microcapsule shell and deliver the lipophilic core material.

In one embodiment, the non-therapeutic methods of use according to the present invention are applicable to fabric steaming, hair straightening, painting, textile processing, and insole making.

Detailed Description

The following description relates to specific embodiments of the invention.

As previously described, the present invention provides formaldehyde-free microcapsules comprising a polymeric shell and a lipophilic active core, which have high thermal stability, break at temperatures above 250 ℃, suitable for applications at high temperatures such as, but not limited to, fabric steaming, hair straightening, painting, textile processing, insole making, and the like, wherein the polymeric shell comprises a crosslinked (meth) acrylic acid-vinyl acetate copolymer.

For the person skilled in the art, microcapsules comprising a lipophilic core material and a microcapsule shell which is thermally stable at 250 ℃ means that the microcapsule shell does not break at 250 ℃.

Any suitable measurement method may advantageously be used to measure the characteristic of thermal stability at 250 ℃.

For example, it may be advantageously measured by taking a microcapsule slurry sample intended for commercialization, such as the microcapsule slurry sample obtained at the end of example 1 below, checking the microcapsule slurry sample using a thermogravimetric analyzer (TGA), subjecting it to a gradually increasing temperature, for example from ambient temperature up to 250 ℃ in 30 ℃ per minute increments, and measuring the lipophilic core material weight loss. When the weight loss of the lipophilic core material is below 7.5 wt%, preferably below 5 wt%, based on the total weight of the encapsulated core material, it can be concluded that the microcapsules are thermally stable at 250 ℃.

For example, if the ambient temperature is 20 ℃, the time duration for which the sample is subjected to a temperature increase up to 250 ℃ and the corresponding TGA observation will take about 7 minutes 40 seconds.

Thus, when the microcapsules are inspected using a thermogravimetric analyzer (TGA), the shell encapsulating the lipophilic core material microcapsules will only break at temperatures above 250 ℃.

Advantageously, another characteristic of the polymeric shell encapsulating the lipophilic core material microcapsules of the present invention is that the shell can prevent loss of the lipophilic core material due to leakage when the microcapsules are exposed to 120 ℃ for a prolonged period of time (e.g., over 30 minutes). This further demonstrates the thermal stability of the microcapsules, which enables the microcapsules to maintain their integrity for longer periods of time in applications requiring prolonged heat exposure.

The shell of the present invention comprises a polymer made from building blocks (which are essentially polymerizable molecules) having a density of 1.05g/cm ³ or higher at 25 ℃ and having a log P value ranging between 0.5 and 4.0, having ester functionality and ester forming functionality.

Log P, by definition, refers to the octanol/water partition coefficient (P) of any individual component, which is the ratio between the equilibrium concentrations of said individual component in octanol and water. The partition coefficient of the components is given in the form of a base 10 Log P. The individual Log P values here are typically provided by the raw material supplier. The combined Log P values of fragrances are determined by averaging the individual Log P values on a wt% basis.

By definition, density herein refers to the individual densities of all materials used, and the values are expressed in g/cm ³ at 25 ℃. These values are collected from SIGMA ALDRICH, india (https:// www.sigmaaldrich.com/IN/en) and/or The Good Scents Company Information System (http:// www.thegoodscentscompany.com /). The density of the fragrances in examples 1-3 was measured using the pycnometer using the ATSM D369 method at 25 ℃.

The polymerizable molecule in the present invention refers to an organic molecule having one or more ethylenically unsaturated moieties.

By definition, the aqueous microcapsule composition or slurry in the present invention refers to an aqueous medium containing dispersed microcapsules in the presence of an emulsifier, wherein the microcapsules contain a lipophilic core (e.g. fragrance) and a polymeric shell formed by initiating polymerization of ethylenically unsaturated molecules at elevated temperature by an oil-soluble (thermal) initiator. The final product of example 1 is referred to as an aqueous microcapsule composition or slurry according to the invention.

For example, as shown in the foregoing example 1, the emulsifier is present in the final slurry, most of the initiator generates lauric acid radicals, which then start to form the crosslinked shell polymer, and the remaining lauric acid radicals form lauric acid, and thus remain dissolved/entrapped in the core.

By definition, a polymerizable molecule having an ester functionality is referred to as an ethylenically unsaturated molecule having at least one ester moiety.

By definition, a polymerizable molecule having an ester-forming functional group is further defined as an ethylenically unsaturated molecule having at least one free acid functional group that can be chemically converted to an ester moiety. Examples of such polymerizable molecules having one free acid functional group are, but are not limited to, acrylic acid, methacrylic acid, crotonic acid, 2-carboxyethyl acrylate, glutaconic acid, 3-dimethacrylate, itaconic acid, maleic acid, fumaric acid, and the like.

The building blocks in the present invention comprise (a) more than 30% by weight of one or more polymerizable molecules having one free acid functional group, based on the total weight of the shell.

The building blocks of the present application comprise (b) one or more polymerizable molecules having an ester functionality of the formula:

Wherein r1=h/CH ₃,

R2＝-OH、-(CH₂)_n-OH、O-CH₃、-O-(CH₂)_m-OH、-O-(CH₂)_n–CH₃、

N=1 to 10, m=2 to 10,

R3=methyl or ethyl.

Examples of polymerizable molecules having an ester functionality of the above formula are, but are not limited to, 2-hydroxyethyl methacrylate, poly (ethylene glycol) methacrylate, poly (propylene glycol) methacrylate, 4-hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, and the like.

The building block in the present invention comprises (c) less than 60% by weight of the shell of two or more polymerizable molecules having more than one ester functional group, wherein each molecule in the building block composition is less than 30% by weight of the shell.

Examples of polymerizable molecules having more than one ester functional group are, but are not limited to, ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1, 4-butanediol diacrylate, 1, 4-butanediol dimethacrylate, 1, 6-hexanediol dimethacrylate, glycerol diacrylate, glycerol dimethacrylate, 1, 10-decanediol dimethacrylate, bis [2- (methacryloyloxy) ethyl ] phosphate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, and the like.

The building block of the application comprises (d) vinyl acetate.

The total weight% of (a), (b), (c) and (d) is 100% to form the shell according to the invention.

The microcapsules of the invention are obtained by a three-step process comprising i) pre-heating/pre-polymerizing building blocks (i.e. polymerizable molecules) in the lipophilic active core phase in the presence of an oil-soluble initiator, ii) emulsifying the core in the aqueous phase, iii) heating the emulsion at an elevated temperature to form a crosslinked shell polymer.

The detailed process for preparing microcapsules according to the invention may advantageously comprise the following steps:

1.a) dissolving the polymerizable molecules (i.e. building blocks) and initiator in a lipophilic core, i.e. oil phase, b) heating the oil phase under nitrogen at 40-55 ℃ while stirring at 100-200rpm for 15-45 minutes to form a prepolymer;

2. dissolving an emulsifier in the aqueous phase;

3. emulsifying the oil phase of step 1 into the water phase of step 2 by stirring at 500-1500rpm using a propeller stirrer for up to 12 minutes;

4. The emulsion is first heated at 40-60 ℃ under nitrogen for 15 to 45 minutes at 100-400rpm and then at 65-85 ℃ for 4-6 hours;

5. the unreacted monomers were quenched at 65-85 ℃ by adding aqueous persulfate solution.

The core of the microcapsules in the present invention comprises a lipophilic active having a density equal to or less than 0.95g/cm ³ at 25 ℃ and a combined log P of 2.5-6.0. The core comprises 15-45% by weight of the aqueous microcapsule composition. While the core to shell ratio varies from 15:1 to 1:5, for example from 15:1 to 1:3 or from 15:1 to 2:5. The total solids of the aqueous microcapsule composition, which comprises lipophilic core-polymer shell microcapsules, emulsifiers and other ingredients, varies between 18-65 wt.%.

The lipophilic core mainly comprises, but is not limited to, fragrances, fragrance precursors, emollient oils, essential oils, hair and skin benefit agents, conditioning actives, cosmetic and personal care actives, uv absorbers, vitamins and antioxidants, antimicrobial and antiviral agents, flavors, deodorants, medicaments, dyes and printing inks, pesticides and microbiocides, agrochemicals, coating materials, anti-aging actives, and the like.

The emulsifiers used in the present application are essentially anionic, nonionic and cationic small molecules, oligomers and polymers. Examples of anionic emulsifiers are salts of alkyl sulphates, alkyl ether sulphates, alkyl carboxylates, alkyl succinamates, alkyl sulphosuccinates, alkyl sulphates such as sodium dodecyl sulphate, alkyl sarcosinates, alkyl or alkyl ether or alkylaryl ether phosphates, ammonium stearate, sodium or potassium stearate, ammonium oleate, sodium or potassium oleate or palmitate, sodium or potassium palmitate, alkylaryl sulphonates such as sodium dodecyl benzene sulphonate, sodium dialkyl sulphosuccinate, dioctyl sulphosuccinate, dilaurylsulphosuccinate. Nonionic emulsifiers useful in the present application are, but are not limited to, acetylated monoglycerides, lactoylated monoglycerides, phosphorylated or sulfated tristyrylphenol polyoxyethylene ethers, secondary alcohol polyoxyethylene ethers, oligoethylene glycol esters of fatty acids, lactoylated propylene glycol monoglycerides, sorbitan esters, sorbitan-polyoxyethylene monoglycerides, polyglycerol esters, diacetyl tartaric acid esters of monoglycerides, succinylated esters of monoglycerides. The polymeric emulsifiers used in the present application are nonionic surfactants such as diblock copolymers of polyethylene oxide and polyethylene or polypropylene oxide, sodium polystyrene sulfonate, isobutylene-maleic anhydride copolymers, acacia, sodium alginate, carboxymethyl cellulose, cellulose sulfate and pectin, poly (styrene sulfonate), acacia, carrageenan, sodium alginate, pectic acid, tragacanth and agar, carboxymethyl starch, phosphated starch, lignin sulfonic acid, polyacrylic acid, polymethacrylic acid, butyl acrylate copolymers or crotonic acid homopolymers and copolymers, vinylbenzenesulfonic acid or 2-acrylamide-2-methylpropanesulfonic acid homopolymers and copolymers, and partial amides or partial esters of such polymers and copolymers, carboxy-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol and phosphoric acid-modified polyvinyl alcohol, and mixtures thereof.

The amount of emulsifier ranges between 0.05 and 5% by weight of the microcapsule composition described herein.

In one non-limiting embodiment, the initiator used to prepare the microcapsules and dissolved in the lipophilic core is a thermal initiator selected from the group consisting of dibenzoyl peroxide, dioctyl peroxide, dilauroyl peroxide, didecanoyl peroxide, t-butyl peracetate, t-butyl perlaurate, t-butyl perbenzoate, di (cetyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, t-butylhydroperoxide, cumene hydroperoxide, ethylcumene peroxide, diisopropylhydroxydicarboxylate, and combinations thereof.

The initiator used in the present application is 0.2 to 5% by weight of the microcapsule composition.

In one non-limiting embodiment, the quencher is used during the preparation of the microcapsule. For example, from 0.02 to 0.5% by weight of the microcapsule composition of ammonium peroxodisulfate or potassium peroxodisulfate is used as a quencher in the present invention in the form of an aqueous solution. Potassium peroxodisulfate is also known as potassium peroxodisulfate (K ₂S₂O₈). It is generally used as an oxidizing agent and a polymerization initiator in organic synthesis.

The particle size of the microcapsule compositions proposed in the present invention ranges between Dv (90) values of 8-35um, as measured using Malvern Mastersizer 3000,3000.

The application product comprises the following steps:

The microcapsule compositions according to the invention are suitable for use in, but not limited to, household and personal care products, textile products, printing and coating applications, pharmaceutical formulations, consumer products and agricultural industry formulation products.

Non-limiting examples of household care products containing microcapsules according to the present application can be divided into 1. Air care products, 2. Household cleaners, 3. Dishwashing products, 4. Laundry/fabric care products. Examples of air care products are generally i) aqueous air freshener liquids, gels, sprays, upholstery fresheners and sprays, and liquids for dosing articles, ii) tablets, pills, blocks, pastes, and the like. 2. Household cleaners having the microcapsule composition according to the application are multi-surface cleaners, carpet cleaners, hard surface cleaners and the like. 3. According to the application, the dishwashing products are liquid dishwashing detergents, dishwashing tablets, and cubes, etc. 4. According to one embodiment of the present application, laundry/fabric care products are primarily liquid and solid laundry detergents, fabric conditioners, fabric fresheners, fabric stiffening agents, soil release articles, fabric freshening sprays, solid fabric softeners and freshening articles, cone shaped fabric fresheners and the like.

Examples of personal care products having a lipophilic core in microcapsules according to the invention as active are leave-on and rinse-off hair and skin care compositions such as shampoos, conditioners, depilatories, hair styling gels, hair dyes, antiperspirants/deodorants, moisturizing sprays (aqua mix), and spray and roller ball products, body washes, body gels, hand washes, soaps, body milks, facial masks, creams, facial essences, sunscreens, and the like. Examples of cosmetic products that include microcapsules include, but are not limited to, lip gloss products, foundations, pre-cosmetic creams, eye shadows, and the like.

Non-limiting examples of pharmaceutical formulations are mainly dermatological products such as ointments, sprays, creams, lotions, gels, transdermal patches and the like.

Microcapsules with fragrances, antimicrobial agents and antiviral agents according to the present report are used in textile/fabric manufacturing to combat malodour and microorganisms. In addition, microcapsules are also used in diapers and sanitary napkins.

The printing formulations with microcapsules according to the application are used in inkjet printing, spray coating, flexographic printing, cylinder and barrel printing, stencil printing, digital printing and the like, wherein the lipophilic core of the microcapsules contains dyes and printing inks, fragrances, fragrance precursors, antimicrobial and antiviral agents, deodorants and the like. According to one embodiment of the application, the coating material for encapsulation is selected from non-limiting examples, wherein the core contains an oil-soluble material having film-forming properties on skin and hair, such as vinylpyrrolidone/hexadecene and vinylpyrrolidone/eicosene copolymers, triacontyl polyvinylpyrrolidone, and the like.

Non-limiting examples of consumer products comprising microcapsules according to the invention are paints, polishes for hard surfaces, shoe insoles and the like.

Examples

EXAMPLE 1 preparation of microcapsule compositions according to the invention

Raw materials for preparing aqueous microcapsule slurry

Composition of oil phase 1:

Fragrance agent 30g (lipophilic core)

1A, composition of fragrance:

the fragrance has a density of 0.8446g/cm ³ at 25 ℃ and a combined (average) Log P of 3.61

1B methacrylic acid 2.2g

1 C-2-hydroxyethyl methacrylate 0.65g

1D ethylene glycol dimethacrylate 1.05g

Pentaerythritol tetraacrylate: 1.25g

1F vinyl acetate 0.61g

1G dilauryl peroxide 1.2g

Composition of aqueous phase 2:

57.8g of water

25% Sodium dodecyl sulfate aqueous solution 8g

Composition of aqueous phase 3:

0.13g of potassium peroxodisulfate in 10g of water

Method for preparing microcapsule

TABLE 1 detailed preparation of microcapsule formulations according to the invention

Comparative examples 2-3 microcapsule compositions with fragrances of the present invention were prepared according to the prior art to enable comparison of olfactory characteristics

TABLE 2 comparative examples 2-3 of microcapsule compositions according to the prior art

Characterization of the microcapsule composition:

Particle size analysis:

particle size was analyzed using a Mastersizer 3000 with Hydro MV wet dispersion units. Dilute aqueous solutions (0.5 wt%) of the microcapsule compositions of example 1 and comparative examples 2-3 were measured and the data was analyzed using the Mie scattering model and presented in table 3.

TABLE 3 Dv (90) values for the microcapsule compositions of example 1 and comparative examples 2-3

Microcapsule composition	Dv (90) (in um)
		Example 1	25.2
Comparative example 2	28.8
		Comparative example 3	9.05

Analysis of the percentage of free oil after microencapsulation:

1g of the microcapsule composition slurry of example 1 was mixed with 5g of hexane in a sealed tube. The mixture was shaken in an orbital shaker at 300rpm for 15 minutes. The sample was then allowed to stand for 10 minutes. The supernatant was passed through a 0.45um filter and analyzed by GC. The remaining fragrance was quantified using a Agilent INTOVU G3950A GC with column part number 19091S-433UI-INT HP-5MS UI 30m,0.25um. The microcapsule composition of example 1 had little free oil remaining (0.13% of the total core).

TABLE 4 free oil analysis of the microcapsule compositions of example 1 and comparative examples 2-3

Microcapsule composition	Free oil percentage of microcapsule composition
		Example 1	0.13
Comparative example 2	0.45
		Comparative example 3	2.25

This well suggests that our microcapsules have superior encapsulation properties, as it is becoming increasingly important to develop consumer products that will release the active core material on demand, without the potential drawbacks that may occur due to having too much lipophilic material outside the microcapsule and inside the consumer product (before use). This is beneficial for the end use of the microcapsules in consumer products, as it ensures better post-rub performance of the microcapsules (due to effective encapsulation of the core fragrance) via consumer product application (e.g. when treating fabrics with a fabric softener containing the microcapsules). The microcapsules according to the invention have excellent thermal stability, so that the microcapsules can be used at higher temperatures, for example when steaming fabrics treated with a product containing the microcapsules.

Olfactory performance of the fragrance core microcapsules of example 1 and comparative examples 2-3.

Conventional fabric softening formulations were prepared in water according to the recommendations of the supplier (Stepan Company, northbrook, IL 60062,United States) with 5% Stepantex SP-90 as softening active and 0.1% sodium benzoate as preservative. Separate fabric softening formulations were prepared using the separate microcapsule compositions of example 1 and comparative examples 2-3 while maintaining 0.3 wt% of the encapsulated fragrance core in the final softener formulation. The cotton fabric was washed and treated with a softener formulation (dosage of 5g fabric softener formulation in 1l of water) and rinsed for 10 minutes, after which the fabric was kept dry at ambient conditions. For pre-and post-rub phases of the fabric, the olfactory characteristics of the dried fabric were recorded by trained panelists. The average result of fragrance intensity is presented in figure 1. The intensity ratings vary from 1 to 5, with 1 being the weakest and 5 being the strongest in increasing levels. Example 1 shows the highest post-friction strength at the same core (fragrance) loading level compared to the prior art microcapsule composition.

Thermal stability of microcapsule compositions

A. thermal stability of microcapsules

Thermal stability of microcapsules the microcapsule composition was analyzed using PERKIN TGA 4000 instrument, wherein a slurry sample was gradually heated from 30 ℃ to 500 ℃ at 30 ℃ per minute and then gradually heated up to 800 ℃ at 50 ℃ per minute under nitrogen atmosphere. The major weight loss in the thermogram is related to the associated phase change in the microcapsule composition. In the thermogram of fig. 2, a sharp drop in weight is noted around 150-170 ℃, and this is mainly related to the loss of moisture in the composition. The next weight loss is related to the shell damage and evaporation/loss of the core (fragrance). The microcapsule composition of example 1 shows excellent stability around 250 ℃ and shows little weight loss. Thus, it clearly demonstrates the high thermal stability of the microcapsule composition of the invention.

B. core loss at prolonged high temperatures

The core loss at high temperature for extended time (30 minutes) was investigated for example 1 and comparative example 3. This is to confirm the leakage of the core at high temperature. Preventing core loss at high temperatures is a necessary condition for microcapsules to be used at high temperatures. Example 2 was not considered due to its low performance (as demonstrated in fig. 1). The sample was gradually heated from 30 ℃ to 120 ℃ at 3 ℃ per minute and then held at 120 ℃ for 30 minutes. The sample was gradually further heated to 800 ℃ at 50 ℃ per minute under nitrogen atmosphere. The weight loss of the microcapsule composition over time was monitored at 120 ℃ and is presented in fig. 3. As can be seen from fig. 3, the microcapsule composition of example 1 has no weight loss in the case of exposure of the microcapsules to 120 ℃ for 30 to 60 minutes. Whereas in the case of example 3 there is a significant core loss (almost 10% weight loss) at high temperatures. Thus, the shell composition of the present invention does not result in core (fragrance) loss. This also means the importance of the invention for applications at higher temperatures.

C. High temperature applications

Fabrics to which microcapsules containing a fabric softener were applied were steamed by subjecting cotton fabrics washed and treated with the microcapsule composition of example 1 of the present invention containing a fabric softener described in detail above to hot steam for 3 minutes. The fabric was then evaluated before and after rubbing after cooling to room temperature. As previously mentioned, the intensity ratings vary from 1-5, with 1 being the weakest and 5 being the strongest in increasing levels. It was observed that after steam treatment, the effect on the microcapsule strength was almost negligible according to the average post-friction value.

Claims

1. A microcapsule comprising a lipophilic core material and a microcapsule shell, wherein the microcapsule shell is formed by oil-in-water emulsion polymerization of a monomer mixture, more than 50% by weight of the monomer mixture being composed of monomers having a density greater than 1.05, the monomer mixture comprising a) more than 30% by weight of one or more ethylenically unsaturated acid monomers, b) one or more monofunctional acrylate and/or methacrylate monomers, c) one or more multifunctional acrylate and/or methacrylate monomers, and d) vinyl acetate monomers, based on the total weight of the monomer mixture.

2. The microcapsule according to claim 1, which is thermally stable at 250°C.

The microcapsule according to claim 1 , which does not contain formaldehyde.

4. The microcapsule according to claim 1, wherein the log P value of all monomers contained in the monomer mixture ranges from 0.5 to 4.0.

5. The microcapsule according to claim 1, wherein the ethylenically unsaturated acid monomer is selected from acrylic acid, methacrylic acid, crotonic acid, 2-carboxyethyl acrylate, glutaconic acid, 3,3-dimethylacrylic acid, itaconic acid, maleic acid, fumaric acid or a mixture of two or more of the acids.

6. The microcapsule of claim 1, wherein the ethylenically unsaturated acid monomer is methacrylic acid.

7. The microcapsule according to any one of claims 5 or 6, wherein the concentration of the ethylenically unsaturated acid monomer in the monomer mixture is equal to or less than 45 wt% based on the total weight of the monomer mixture.

8. The microcapsule according to any one of claims 5 or 6, wherein the concentration of the ethylenically unsaturated acid monomer in the monomer mixture is between 30 and 45 weight percent based on the total weight of the monomer mixture.

9. The microcapsule according to claim 1, wherein the monofunctional acrylate and/or methacrylate monomer is selected from polymerizable molecules having one ester functional group or a mixture of two or more of the monomers of the following formula:

in

R1＝H/CH ₃ ,

R2=-OH, -(CH ₂ ) _n -OH, O-CH ₃ , -O-(CH ₂ ) _m -OH,

-O-(CH ₂ ) _n –CH ₃ , -(O-CH ₂ -CH ₂ ) _n -OH, -(O-CH ₂ -CH ₂ -CH ₂ ) _n -OH,

-(O-CH ₂ -CH ₂ ) _n -O-CH ₃ , -(O-CH ₂ -CH ₂ ) _n -O-CH ₂ -CH _{3 ,}

-(O-CH ₂ -CH ₂ -CH ₂ )nO-CH ₂ -CH ₃ , -(O-CH ₂ -CH ₂ -CH ₂ )nO-CH ₃ ,

-(O-CH ₂ -CHR 3 ) _n -CH ₃

n=1 to 10, m=2 to 10, and R3=methyl or ethyl.

10. The microcapsule according to claim 1, wherein the monofunctional acrylate and/or methacrylate monomer is selected from 2-hydroxyethyl methacrylate, poly(ethylene glycol) methacrylate, poly(propylene glycol) methacrylate, 4-hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate or a mixture of two or more of said monomers.

11. The microcapsule according to claim 1, wherein the monofunctional acrylate and/or methacrylate monomer is hydroxyethyl methacrylate.

12. The microcapsule according to any one of claims 9 to 11, wherein the concentration of the monofunctional acrylate and/or methacrylate monomer is between 5 and 50 wt% based on the total weight of the monomer mixture.

13. The microcapsule according to claim 1, wherein the multifunctional acrylate and/or methacrylate monomers are selected from polymerizable molecules having more than one ester functional group.

14. The microcapsule according to claim 1, wherein the multifunctional acrylate and/or methacrylate monomer is selected from ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, glycerol diacrylate, glycerol dimethacrylate, 1,10-decanediol dimethacrylate, bis[2-(methacryloyloxy)ethyl]phosphate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate or a mixture of two or more of the monomers.

15. The microcapsule according to claim 14, wherein the multifunctional acrylate and/or methacrylate monomer is a mixture of two or more of the monomers, each of the monomers accounting for less than 30 wt% based on the total weight of the monomer mixture.

16. The microcapsule according to any one of claims 13 to 15, wherein the total concentration of multifunctional acrylate and/or methacrylate monomers in the monomer mixture is less than 60 wt% based on the total weight of the monomer mixture.

17. The microcapsule according to any one of claims 13 to 15, wherein the concentration of the multifunctional acrylate and/or methacrylate monomer in the monomer mixture is between 20 and 50 wt% based on the total weight of the monomer mixture.

18. The microcapsule of claim 1, wherein the concentration of the vinyl acetate monomer in the monomer mixture is between 0.05 and 15 weight percent based on the total weight of the monomer mixture.

19. The microcapsule of claim 1, wherein the concentration of a) ethylenically unsaturated acid monomers, b) monofunctional acrylate and/or methacrylate monomers, c) multifunctional acrylate and/or methacrylate monomers, and d) vinyl acetate monomers is at least 95 weight percent based on the total weight of the monomer mixture.

20. The microcapsule according to claim 19, wherein the concentration of [a) + b) + c) + d)] is 100 wt% based on the total weight of the monomer mixture.

21. The microcapsule of claim 1, wherein the microcapsule has a particle size ranging from 8 to 35 microns in Dv(90) value.

22. The microcapsule of claim 1, wherein the lipophilic core material of the microcapsule has a density equal to or less than 0.95 g/ ^cm3 at 25°C and a combined log P between 2.5 and 6.0.

23. The microcapsule of claim 1, wherein the lipophilic core material of the microcapsule comprises at least 95 wt % of one or more of the following ingredients, based on the total weight of the lipophilic core material: fragrances, fragrance precursors, emollient oils, essential oils, hair benefit agents, skin benefit agents, conditioning agent actives, cosmetic care actives, personal care actives, UV absorbers, vitamins, antioxidants, antimicrobial agents, antiviral agents, flavoring agents, anti-odor agents, pharmaceutical agents, dyes, printing inks, pesticides, microbicides, agrochemicals, coating materials, anti-aging actives.

24. The microcapsule of claim 23, wherein the lipophilic core material of the microcapsule comprises one or more of the following ingredients: fragrance, essential oil, hair benefit agent, skin benefit agent, antimicrobial agent, antiviral agent, anti-odor agent.

25. The microcapsule of claim 1, wherein the weight of the lipophilic core material divided by the weight of the microcapsule shell is between 15 and 0.33.

26. An aqueous microcapsule composition comprising water and the microcapsule according to claim 1, wherein the water accounts for 35 to 82 weight % of the total weight of the aqueous microcapsule composition.

27. The aqueous microcapsule composition according to claim 26, wherein the lipophilic core material accounts for 15 to 45 weight % of the total weight of the aqueous microcapsule composition.

28. The aqueous microcapsule composition according to claim 26, comprising one or more emulsifiers, wherein the emulsifiers account for 0.05 to 5 weight percent of the total weight of the aqueous microcapsule composition.

29. The aqueous microcapsule composition of claim 28, wherein the weight of water, microcapsules and emulsifier accounts for at least 90 weight percent of the total weight of the aqueous microcapsule composition.

30. A method for preparing an aqueous microcapsule composition as claimed in any one of claims 26 to 29, comprising the following steps:

(1) dissolving the monomer mixture together with an initiator in an oil phase containing the lipophilic core material and heating the oil phase to form a prepolymer,

(2) dissolving the emulsifier in the water phase,

(3) emulsifying the oil phase of step 1 into the water phase of step 2, and

(4) Heating the emulsion from step 3 to form a suspension of core-shell microcapsules in water.

31. The method according to claim 30, wherein the emulsification step of the core phase in the aqueous phase is obtained by stirring with a propeller stirrer at 500-1500 rpm for up to 12 minutes.

32. A method of non-therapeutic use of a microcapsule according to any one of claims 1 to 25 or an aqueous microcapsule composition according to any one of claims 26 to 29, comprising using the microcapsule to deliver a lipophilic core material of an industrial composition related to home care products, personal care products, textile products, printing and coating application products, pharmaceutical formulation products, consumer product products and agricultural industrial formulation products.

33. The non-therapeutic method of use according to the preceding claim, wherein the mechanical stress and temperature conditions to which the microcapsules are exposed are sufficient to destroy the microcapsule shell and deliver the lipophilic core material.

34. Non-therapeutic use according to the preceding claims for fabric steaming, hair straightening, painting, textile processing and insole making.