Polyurea / polyurethane microcapsules

Abstract

The present invention relates to a method for preparing polyurea / polyurethane microcapsules containing at least one lipophilic active substance, preferably polyurea / polyurethane microcapsules containing fragrances or essences, which method can be carried out independently of the pH value compared to the methods for preparing polyurea / polyurethane microcapsules in the prior art. In addition, the present invention relates to polyurea / polyurethane microcapsules, which are obtained according to the method of the present invention. In another aspect, the invention described herein relates to the use of such microcapsules or microcapsule dispersions for the manufacture of household goods, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance emulsions or fragrance enhancers, cosmetics, personal care products, agricultural products, pharmaceutical products or paper printing coatings, etc. Finally, the present invention relates to consumer products containing such polyurea / polyurethane microcapsules.

Description

Technical Field

[0001] The present invention relates to a method for preparing polyurea / polyurethane microcapsules containing at least one lipophilic active substance, preferably polyurea / polyurethane microcapsules containing fragrances or essences, which can be carried out independently of the pH value compared to the methods for preparing polyurea / polyurethane microcapsules in the prior art. In addition, the present invention relates to polyurea / polyurethane microcapsules, which are obtained according to the method of the present invention. In another aspect, the invention described herein relates to the use of such microcapsules or microcapsule dispersions for the manufacture of household goods, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance lotions and fragrance enhancers, cosmetics, personal care products, agricultural products, pharmaceutical products or paper printing coatings. Finally, the present invention relates to consumer products containing such polyurea / polyurethane microcapsules. Background Art

[0002] Microcapsules are particles consisting of a core and a wall material that encapsulates the core, wherein the core can be a solid, liquid or gaseous substance, which is encapsulated by a polymerized, dense, permeable or semi-permeable wall material. During the preparation process, the polymer formed by the starting components is deposited on the substance to be encapsulated through emulsification and coagulation or interfacial polymerization, thereby fixing it. The core is also called the inner phase. Names such as outer phase, shell or encapsulation layer are also used for the wall, which is therefore fixed. The diameter of the microcapsule is generally in the range of 1 to 1000 μm. The wall thickness is generally 0.5 to 150 μm. Typically, the loading amount can be 25 to 95% by weight, but can also be 1 to 99% by weight.

[0003] Furthermore, the purpose of encapsulation is to protect the encapsulated substances or active substances, to release them in a targeted manner at a specific time, to convert liquids into a controlled powder form, to prevent or delay the loss of volatile components (e.g. in the case of aromas or flavorings), to prevent premature chemical reactions with other mixture components, or to ensure better handling before or during processing. Lipophilic or hydrophobic active substances, such as aromas or flavorings, can be easily incorporated into many different application formulations by encapsulation.

[0004] The contents of the microcapsules can be released in various ways and in particular based on one of the mechanisms described below: mechanical destruction of the capsule by crushing or shearing; destruction of the capsule by melting of the wall material, destruction of the capsule by dissolution of the wall material or diffusion of the active substance through the capsule wall.

[0005] It is known that a variety of shell materials can be used to prepare microcapsules. The shell can be composed of natural, semi-synthetic or synthetic materials. For example, natural shell materials are gum arabic, agar, agarose, maltodextrin, alginic acid or its salts, such as sodium alginate or calcium alginate, fats and fatty acids, cetyl alcohol, collagen, chitosan, lecithin, gelatin, albumin, shellac, polysaccharides such as starch or dextran, polypeptides, protein hydrolysates, sucrose and wax. Semi-synthetic shell materials are mainly chemically modified cellulose, especially cellulose esters and cellulose ethers, such as cellulose acetate, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carboxymethyl cellulose, and starch derivatives, especially starch ethers and starch esters. Synthetic shell materials are, for example, polymers, such as polyacrylates, polyamides, polyvinyl alcohol or polyvinyl pyrrolidone.

[0006] Depending on the type of shell material and the preparation method, microcapsules with different characteristics in terms of diameter, particle size distribution and physical and / or chemical properties are produced.

[0007] Polyurea microcapsules or polyurea / polyurethane microcapsules formed by the polymerization and / or crosslinking of polyisocyanates with polyamines and / or diols or polyols are known capsules which are used in various technical fields including perfume making.

[0008] For example, polyurea microcapsules obtained by reacting two polyisocyanates and a polyamine are described in WO 2011 / 161229 or WO 2011 / 160733. According to WO 2011 / 161229 or WO 2011 / 160733, the polyurea microcapsules are prepared in the presence of polyvinylpyrrolidone (PVP) as protective colloid. WO 2012 / 107323 discloses polyurea microcapsules with a polyurea shell comprising the reaction product of a polyisocyanate with guanazole (3,5-diamino-1,2,4-triazole) and an amino acid in the presence of an anionic stabilizer or surfactant, such as anionic polyvinyl alcohol. PCT / EP2019 / 053600 relates to a process for preparing polyurea / polyurethane microcapsules, which are prepared by the following steps: polyisocyanates are subjected to multiple pH-dependent crosslinking steps with amines that react at acidic pH values ​​and then with amines that react at alkaline pH values ​​in the presence of protective colloids and catalysts.

[0009] The above-mentioned exemplary release systems from the prior art have both good stability, ie the ability to retain the active substance and thus the ability of the capsule to avoid loss of volatile components, and good performance, for example the release of fragrance in the case of fragrance capsules.

[0010] However, the disadvantage of these methods for preparing polyurea / polyurethane microcapsules is that the multi-step crosslinking of isocyanate groups with amine (amino) groups requires precise adjustment of the pH value by adding acid or alkali. In addition, it has been found that various protective colloids such as polysaccharides have pH dependence, thereby losing their emulsifying properties. In addition, most of the methods for preparing polyisocyanate-based capsule shells in the prior art can only be used to encapsulate selected active substances, but are not suitable for encapsulating aromatics or aromatic oils with aldehyde, carboxylic acid or ester functions. In the encapsulation process at alkaline pH values, carboxylic acids are deprotonated, oxidized aldehydes (carboxylic acids) are similarly deprotonated and esters are saponified, resulting in the loss of active substances, and on the other hand, the obtained emulsions also become unstable. Therefore, for active substances, the use of this microencapsulation method has limitations, so for example, it is only applicable to a small range of aromatics or flavorings, while this microencapsulation method is excluded for aromatics or flavorings with aldehyde, carboxylic acid or ester functions. However, aromatics or flavorings with aldehyde, carboxylic acid or ester functions belong to the most important representatives of aromatics or aromatic oils.

[0011] Against this background, the object of the present invention is to provide a process for producing polyurea / polyurethane microcapsules which allows the production of microcapsules having outstanding stability and outstanding release properties for the respective application, while also allowing emulsification and crosslinking of the capsule material without pH adjustment, thus shortening and simplifying the process.

[0012] Surprisingly, it has been found that this object can be achieved by emulsifying the polyisocyanate and the active substance to be encapsulated in an aqueous solution containing a protective colloid and an emulsifier, obtaining an emulsion, and then, in a subsequent step, crosslinking the polyisocyanate stepwise with an amino acid or an amino acid hydrochloride, a hydroxyl donor and a basic amine and / or a guanidine donor in the presence of a catalyst, without the need for pH adjustment in the individual crosslinking steps. Summary of the invention

[0013] The present problem posed here is solved by the subject matter of the independent claims. Preferred embodiments emerge from the text of the dependent claims and from the following description.

[0014] Therefore, a first subject of the present invention relates to a method for preparing polyurea / polyurethane microcapsules, which method comprises the following steps in sequence:

[0015] (a) performing a first polymerization and / or cross-linking step by:

[0016] (a1) providing an inner non-aqueous phase comprising at least one polyisocyanate having two or more isocyanate groups and at least one active substance to be encapsulated;

[0017] (a2) providing an external aqueous phase comprising at least one protective colloid and optionally at least one emulsifier;

[0018] (a3) mixing the inner non-aqueous phase and the outer aqueous phase to obtain an oil-in-water emulsion or dispersion;

[0019] (a4) adding at least one amino acid or amino acid hydrochloride and a catalyst;

[0020] (b) carrying out a second polymerization and / or crosslinking step by adding at least one hydroxyl donor;

[0021] (c) performing a third polymerization and / or crosslinking step by adding at least one basic amine and / or guanidine donor to obtain a microcapsule dispersion;

[0022] (d) curing the microcapsule dispersion at a temperature of at least 60° C. for at least 60 minutes; and

[0023] (e) optionally separating the microcapsules from the reaction mixture and optionally drying the microcapsules or adjusting the viscosity of the microcapsule slurry by adding a thickener.

[0024] Furthermore, the subject of the invention described here is a polyurea / polyurethane microcapsule comprising at least one lipophilic active substance prepared by the process according to the invention.

[0025] Another aspect of the present invention is a polyurea / polyurethane microcapsule comprising:

[0026] a core comprising at least one hydrophobic active substance; and

[0027] A capsule shell comprising a reaction product produced from:

[0028] - polymerization and / or crosslinking of polyisocyanates having two or more isocyanate groups with at least one amino acid or amino acid hydrochloride and a catalyst in the presence of a protective colloid,

[0029] - further polymerization and / or crosslinking with at least one hydroxyl donor, and

[0030] - Further polymerization and / or crosslinking with at least one basic amine and / or guanidinium donor.

[0031] Finally, the present invention relates in another aspect to the use of the polyurea / polyurethane microcapsules or polyurea / polyurethane microcapsule dispersions according to the invention for the manufacture of household goods, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance lotions or fragrance enhancers, cosmetics, personal care products, fragrance compositions, agricultural products, pharmaceutical products or paper printing coatings, and consumer products prepared therefrom.

[0032] Surprisingly, it was found within the scope of the present invention that, during the preparation of the microcapsules, the polyisocyanate and the lipophilic active substance form an emulsion in the presence of a protective colloid and optionally an emulsifier, the catalyst is added only after the emulsion has been formed, and then the polyisocyanate having at least two or more isocyanate groups is polymerized and / or crosslinked in a targeted manner with an amino acid or an amino acid hydrochloride, and then further polymerized and / or crosslinked with a hydroxyl donor, and further polymerized and / or crosslinked with a basic amine and / or guanidine donor, and the combination of the above steps produces stable microcapsules, thereby ensuring effective encapsulation of the active substances and subsequent targeted release of these active substances, wherein the emulsion formation and the stepwise polymerization and / or crosslinking of the polyisocyanate do not require pH adjustment.

[0033] By carrying out the method steps according to the invention in sequence and adding the catalyst only after the emulsification step, polyurea / polyurethane microcapsules can be prepared which have both better stability and better sensory properties than the polyurea / polyurethane microcapsules of the prior art.

[0034] Furthermore, the sequential performance of the method steps according to the invention and the addition of the catalyst only after the emulsification step results in a capsule shell or capsule wall whose composition differs from that of the microcapsules of the prior art.

[0035] For those skilled in the art, these and other aspects, features and advantages of the present invention will be clear and distinct through the study of the following detailed description and claims. In this article, any feature of one aspect of the present invention can be used or replaced in another aspect of the present invention. The embodiments herein illustrate the present invention by way of example, but do not limit the present invention.

[0036] As used herein, the terms "at least one" or "at least one" or "one or more" refer to 1 or more, such as 2, 3, 4, 5, 6, 7, 8, 9 or more.

[0037] The term "and / or" indicates that there is a connection or provides alternatives.

[0038] Numerical examples given in the format "from x to y" are inclusive of the values ​​given. If multiple preferred numerical ranges are given in this format, all ranges combining the different endpoints are also intended to be considered. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1is an optical microscope image of a microcapsule according to the present invention. The microcapsule was prepared by combining hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 75:25. In addition, lysine*HCl was used as the first amino acid, glycerol was used as a hydroxyl donor, and guanidine carbonate was used as a basic amine / guanidinium donor. DABCO was used as a catalyst, Seyal type gum arabic was used as a protective colloid, and quaternized hydroxyethyl cellulose was used as an emulsifier. Optical microscope imaging was performed using an Olympus BX51. The displayed bar corresponds to 100 μm.

[0040] Figure 2 A schematic diagram of the particle size distribution (d(0.5) value) of microcapsules according to the invention and prior art microcapsules based on a polyurea / polyurethane structure is shown, wherein the catalyst is added to the aqueous phase before emulsification and dissolved therein. The particle size distribution is determined using a Malvern Mastersizer 3000. The corresponding calculation is based on the Mie theory.

[0041] Figure 3 The following is a schematic diagram showing the infrared spectrum analysis results of the microcapsules of the prior art and the capsules according to the present invention. The analysis was performed using ATR infrared spectroscopy (English: Attenuated total reflection). Figure 3 In the , decimals on the absorption axis are marked with a dot instead of a comma as the decimal separator.

[0042] Figure 4 A schematic diagram showing the sensory evaluation results of the microcapsules according to the present invention and the microcapsules of the prior art (ie, microcapsules based on polyurea / polyurethane structures, in which the catalyst is added to the aqueous phase and dissolved therein before emulsification) is shown. DETAILED DESCRIPTION

[0043] In a first aspect, the present invention relates to a method for preparing polyurea / polyurethane microcapsules, the method comprising the following steps in order:

[0044] (a) performing a first polymerization and / or cross-linking step by:

[0045] (a1) providing an inner non-aqueous phase comprising at least one polyisocyanate having two or more isocyanate groups and at least one active substance to be encapsulated;

[0046] (a2) providing an external aqueous phase comprising at least one protective colloid and optionally at least one emulsifier;

[0047] (a3) mixing the inner non-aqueous phase and the outer aqueous phase to obtain an oil-in-water emulsion or dispersion;

[0048] (a4) adding at least one amino acid or amino acid hydrochloride and a catalyst;

[0049] (b) carrying out a second polymerization and / or crosslinking step by adding at least one hydroxyl donor;

[0050] (c) performing a third polymerization and / or crosslinking step by adding at least one basic amine and / or guanidine donor to obtain a microcapsule dispersion;

[0051] (d) curing the microcapsule dispersion at a temperature of at least 60° C. for at least 60 minutes; and

[0052] (e) optionally separating the microcapsules from the reaction mixture and optionally drying the microcapsules or adjusting the viscosity of the microcapsule slurry by adding a thickener.

[0053] In the context of the present invention, microcapsules are understood to be microparticles having a capsule shell or capsule wall and at least one or more active substances as the core material inside the capsule. Preferably, the active substance is a lipophilic or hydrophobic active substance. Such active substances are insoluble or poorly soluble in water, but are easily soluble in fats and oils. In the present invention, the terms "microcapsules" or "capsules" and "lipophilic" or "hydrophobic" are used synonymously.

[0054] Within the scope of the present invention, the capsule shell or capsule wall is preferably composed of a plurality of crosslinked units or a crosslinked matrix, which preferably has different compositions and is produced in the preparation of the microcapsules according to the invention by a plurality of method steps or process sequences or crosslinking steps, thereby forming a three-dimensional network.

[0055] A crosslinking unit or crosslinking matrix in the context of the present invention is a complex or network of starting components for building a microcapsule shell, which is built and / or embedded in other components of the microcapsule shell by linear or three-dimensional polymerization and / or crosslinking of functional groups of the starting components with each other and / or with other components of the microcapsule shell. In the process according to the invention, a plurality of crosslinking units or crosslinking matrices can in turn be crosslinked with each other by further crosslinking to form a three-dimensional structure for building a microcapsule shell or a microcapsule wall. The crosslinking units or crosslinking matrix in their entirety constitute the capsule shell or the capsule wall.

[0056] In a more preferred variant of the invention, the capsule shell or capsule wall comprises at least a polyurea and a polyurethane crosslinking matrix or crosslinking units.

[0057] In the first step (a) of the process according to the invention, a first crosslinking and / or polymerization (a) is carried out. For this purpose, an internal non-aqueous phase (a1) is provided, which comprises at least one isocyanate or a polyisocyanate having two or more isocyanate groups and at least one lipophilic active substance to be encapsulated.

[0058] The polyurea / polyurethane microcapsules according to the present invention are prepared using at least one or more polyisocyanates.

[0059] The at least one isocyanate or polyisocyanate having two or more isocyanate groups used in the process according to the invention for preparing polyurea / polyurethane microcapsules has at least two isocyanate groups for forming a polymer network by crosslinking and / or polymerization, which network forms the capsule shell or capsule wall.

[0060] Polyisocyanates are R-substituted organic derivatives (RN=C=O) of isocyanic acid (HN=C=O). Organic isocyanates are compounds in which an isocyanate group (-N=C=O) is bonded to an organic group. Polyfunctional isocyanates or polyisocyanates are compounds which contain at least two or more, i.e. 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 50, 100, 200 or even more isocyanate groups (-N=C=O) in the molecule. Polyisocyanates having two isocyanate groups are also called diisocyanates.

[0061] Polyisocyanates can be divided into aliphatic, cycloaliphatic, hydrogenated aromatic, aromatic or heterocyclic isocyanates or polyisocyanates. Furthermore, the polyisocyanates according to the invention may be linear or branched.

[0062] Polyisocyanates, especially aromatic polyisocyanates, are highly reactive compounds. The polyaddition reaction of polyisocyanates with diols or polyols is the basis of polyurethane chemistry, and the polyaddition reaction of polyisocyanates with amines is the basis of polyurea chemistry.

[0063] According to the invention, at least difunctional, preferably polyfunctional, polyisocyanates are used, ie all aliphatic, cycloaliphatic and aromatic isocyanates are suitable provided they have at least two reactive isocyanate groups.

[0064] Particularly preferred are aliphatic, alicyclic, hydrogenated aromatic, aromatic or heterocyclic polyisocyanates and substitution products thereof and mixtures of the above monomers or oligomers. Among the above polyisocyanates, aliphatic and / or aromatic compounds are preferably used.

[0065] In a preferred embodiment of the process according to the invention, the polyisocyanates contain on average 2 to 5 functionalized -N=C=O groups. These include, for example, aliphatic, cycloaliphatic and aromatic diisocyanates, triisocyanates and higher polyisocyanates.

[0066] Among the above polyisocyanates, diisocyanates and polyisocyanates with three functional -NC=O groups are preferred and can therefore be preferably used in the practice of the present invention. Diisocyanates with the general structure O=C=NRN=C=O are preferably used, wherein R represents an aliphatic, alicyclic or aromatic group. Preferably, these groups have 5 or more carbon atoms.

[0067] In a preferred embodiment of the method according to the invention, at least one polyisocyanate having two or more isocyanate groups is selected from the group of aliphatic polyisocyanates and / or aromatic polyisocyanates. In an even more preferred variant of the method according to the invention, the at least one polyisocyanate is a combination of two different aliphatic polyisocyanates, or a combination of an aliphatic and an aromatic polyisocyanate.

[0068] Due to the number of functional groups, an optimized cross-linking or networking of the capsule wall is achieved, thereby providing microcapsules with prolonged sustained release of the active substance and good stability in the consumer product.

[0069] In a preferred variant of the process according to the invention, the polyisocyanate is an aliphatic polyisocyanate.

[0070] The term "aliphatic polyisocyanate" refers to any non-aromatic polyisocyanate molecule. In addition, the polyisocyanate molecule contains at least two isocyanate groups, i.e., at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 50, 100, 200 or more isocyanate groups directly bonded to a corresponding number of different carbon atoms of the same aliphatic molecule, as well as derivatives of such compounds.

[0071] The aliphatic polyisocyanate molecules having at least two isocyanate groups, i.e. at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 50, 100, 200 or more isocyanate groups, may also be linear, branched or cyclic and may have any substitution including, for example, aliphatic substituents, aromatic substituents, one or more heteroatoms such as nitrogen, oxygen, phosphorus and / or sulfur, halogens such as fluorine, chlorine, bromine and / or iodine and / or other functional groups, such as alkoxy groups.

[0072] Preferably, the linear aliphatic polyisocyanate molecule is selected from C2 to C20 linear alkyl, preferably C3 to C15 linear alkyl, C4 to C12 linear alkyl, C5 to C10 linear alkyl, C6 to C9 linear alkyl or C7 to C8 linear alkyl. Preferably, the linear aliphatic molecule does not contain an aromatic structure.

[0073] Preferably, the branched aliphatic polyisocyanate molecules are selected from C2 to C20 branched alkyl, preferably C3 to C15 branched alkyl, C4 to C12 branched alkyl, C5 to C10 branched alkyl, C6 to C9 branched alkyl and C7 to C8 branched alkyl.

[0074] The shorter the carbon chain of the polyisocyanate molecule, the higher the reaction rate compared to its long-chain analogues.

[0075] Cyclic aliphatic polyisocyanate molecules contain at least 1, i.e. 1, 2, 3, 4 or more non-aromatic ring structures, wherein the ring structures themselves are preferably composed only of carbon atoms. Of course, the carbon atoms of the ring structures may carry suitable substituents. Preferably, at least one ring structure is independently composed of 3, 4, 5, 6, 7 or 8-membered rings. Preferably, the cyclic aliphatic molecules contain 2 to 20 carbon atoms, for example 3 to 15 carbon atoms, 4 to 12 carbon atoms, 5 to 10 carbon atoms, 6 to 9 carbon atoms or 7 to 8 carbon atoms.

[0076] In another variant of the process according to the invention, the polyisocyanate is an aromatic polyisocyanate. The term "aromatic polyisocyanate" refers to any polyisocyanate compound in which two or more isocyanate groups are directly bonded to an aromatic carbon atom and which contains, for example, phenyl, tolyl, xylyl, naphthyl or diphenyl units as aromatic components, and derivatives of such polyisocyanate compounds.

[0077] Aromatic polyisocyanates react significantly faster than aliphatic polyisocyanates and are therefore preferably used in the process according to the invention.

[0078] Straight-chain, branched or cyclic aliphatic or aromatic polyisocyanates may be present as monomers or polymers. A monomeric polyisocyanate is a molecule that is not connected to another molecule, in particular not connected via one or more crosslinking agents. A polymeric polyisocyanate comprises at least two monomers connected by one or more crosslinking agents. The at least two monomers are not necessarily the same monomers, but may be different monomers. Preferably, the polymeric polyisocyanate comprises at least 2 or more monomers, i.e. at least 2, 3, 4, 5, 10, 20, 30, 40, 50, 100 or more monomers connected to each other via at least one crosslinking agent.

[0079] Preferably, the linear, branched or cyclic aliphatic or aromatic polyisocyanate has a limited size / molecular weight so as to react with one or more crosslinking agents. Preferably, examples of suitable molecular weights include about 100 g / mol to 5.10 4 g / mol, preferably 120 g / mol to 2.10 4 g / mol, 140 g / mol to 10 4 g / mol, 160 g / mol to 5·103 g / mol, 180 g / mol to 2·10 3 g / mol, 200 g / mol to 10 3 g / mol, 220 g / mol to 900 g / mol, 240 g / mol to 800 g / mol, 260 g / mol to 700 g / mol, 280 g / mol to 600 g / mol, 300 g / mol to 500 g / mol, 320 g / mol to 450 g / mol or 340 g / mol to 400 g / mol.

[0080] Any number of different linear, branched and / or cyclic aliphatic and / or aromatic polyisocyanates may be used. For example, at least one, i.e., at least 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 different linear aliphatic polyisocyanates are used. For example, at least one, i.e., at least 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 different branched aliphatic polyisocyanates are used. For example, at least one, i.e., at least 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 different branched cyclic polyisocyanates are used.

[0081] Preferably, derivatives of straight-chain, branched and / or cyclic aliphatic polyisocyanates are used. Derivatives as used herein are understood in the broadest sense to be compounds derived from a certain compound by chemical reaction. Examples of derivatives include oligomers and / or adducts of the above-mentioned straight-chain or branched aliphatic polyisocyanates. Preferred oligomers are biuret, isocyanurate, uretdione, iminooxadiazinedione, and preferred adducts are trimethylolpropane adducts. These oligomers / adducts are known in the prior art and are disclosed, for example, in US 4855490 A or US 4144268 A.

[0082] Preferably, the aliphatic polyisocyanates are present exclusively in monomeric and / or dimer form (as isocyanates) or in oligomeric form.

[0083] Linear, branched or cyclic polyisocyanate derivatives and / or mixtures thereof can also be obtained by reacting polyisocyanates with polyols (eg glycerol), polyamines and polythiols (eg dimercaptopropanol).

[0084] The isocyanate compound according to the above definition explicitly includes various isomers (if any) alone or in combination. For example, methylene bis (cyclohexyl isocyanate) (H12MDI) includes 4,4'-methylene bis (cyclohexyl isocyanate), 2,4'-methylene bis (cyclohexyl isocyanate) and / or 2,2'-methylene bis (cyclohexyl isocyanate).

[0085] Exemplary aliphatic polyisocyanates include those commercially available, such as BAYHYDUR N304 and BAYHYDUR N3Q5, which are aliphatic water-dispersible polyisocyanates based on hexamethylene diisocyanate; DESMODUR N3600, DESMODUR N3700, and DESMODUR N3900, which are low viscosity, multifunctional aliphatic polyisocyanates based on hexamethylene diisocyanate; and DESMODUR 3600 and DESMODUR N100, which are aliphatic polyisocyanates based on hexamethylene diisocyanate, each of which is available from Bayer Corporation, Pittsburgh, PA.

[0086] According to another preferred variant of the invention, the linear or branched aliphatic polyisocyanate is selected from the group consisting of pentamethylene diisocyanate (PDI, such as Stabio D-370N or D-376N from Mitsui Chemicals Inc., Japan), hexamethylene diisocyanate (HDI), lysine triisocyanate, lysine diisocyanate and derivatives thereof, preferably wherein any of the derivatives comprises more than one isocyanate group and optionally further comprises one or more groups selected from the group consisting of biuret, isocyanurate, uretdione, iminooxadiazinedione and trimethylolpropane adducts, and / or wherein the cyclic aliphatic polyisocyanate is selected from the group consisting of isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI, such as Takenate 6-(2-methylisocyanate) from Mitsui Chemicals Inc., Japan 600), 1,2-bis(methyl isocyanate)cyclohexane, 1,4-bis(methyl isocyanate)cyclohexane, methylenebis(cyclohexyl isocyanate) (H12MDI) and derivatives thereof, preferably, any of said derivatives comprising more than one isocyanate group, and where possible further comprising one or more groups selected from the group consisting of: H6XDI, especially biuret, isocyanurate, uretdione, iminooxadiazinedione and trimethylolpropane adducts (such as TMP adducts) of Takenate D-120N of Mitsui Chemicals, Inc.

[0087] Particularly preferred are aliphatic polyisocyanates obtained from renewable raw materials such as PDI (Stabio D-370N or D-376N from Mitsui Chemicals, Inc., Japan). Studies have found that such aliphatic polyisocyanates obtained from renewable raw materials do not affect the quality / performance of core-shell capsules.

[0088] Other suitable commercially available polyisocyanates include LUPRANAT M20 (BASF), wherein the average n is 0.7; PAPI 27 (Dow Chemical), wherein the average n is 0.7; MONDUR MR (Bayer), wherein the average n is 0.8; MONDUR MR Light (Bayer), wherein the average n is 0.8; MONDUR 489 (Bayer), wherein the average n is 1.0; Poly-[(phenylisocyanat)-co-formaldehyd (Aldrich Chemical, Milwaukee, WI), other isocyanate monomers such as DESMODUR N3200 (Bayer), and TAKENATE D1 10-N (Mitsui Chemicals Corporation, Rye Brook, NY). Other representative polyisocyanates include those named TAKENATE D-1 10N (Mitsui & Co.), DESMODUR L75 (Bayer AG) and DESMODUR IL (Bayer AG).

[0089] In a preferred variant, the polyisocyanates used in the preparation of the polyurea / polyurethane microcapsules according to the invention are used as sole polyisocyanate component, ie no further, different polyisocyanate components are added.

[0090] Examples of monomeric polyisocyanates containing at least two polyisocyanate groups which can be used according to the invention are as follows: ethylene diisocyanate, trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethyl diisocyanate, ethylene diisothiocyanate, tetramethylene diisothiocyanate, hexamethylene diisothiocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1,3-phenylene diisocyanate , 1,4-phenylene diisocyanate, a mixture of 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, p-phenylene diisothiocyanate, xylene-1,4-diisothiocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, and xylene-1,4-diisocyanate and xylene-1,3-diisocyanate. Mixture of isocyanates, 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, a mixture of 2,4-hexahydrotoluene diisocyanate and 2,6-hexahydrotoluene diisocyanate, hexahydro-1,3-phenylene diisocyanate, hexahydro-1,4-phenylene diisocyanate, a mixture of hexahydro-1,4-phenylene diisocyanate and hexahydro-1,4-phenylene diisocyanate, 1,3-benzene diisocyanate, 1,3,5-trimethylbenzene-2,4-diisocyanate, 1,3,5- Triisopropylbenzene-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, triphenylmethane-4,4',4"-triisocyanate, toluene-2,4,6-triisocyanate, dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate or a mixture of the above compounds.

[0091] Polymerizable compounds having at least two polyisocyanate groups, preferably industrially prepared diisocyanates and polyisocyanates, for example TDI: toluene diisocyanate (mixture of isomers of 2,4- and 2,6-toluene diisocyanate in a ratio of 80:20), HDI: hexamethylene-1,6-diisocyanate, IPDI: isophorone diisocyanate or DMDI: diphenylmethane-4,4′-diisocyanate.

[0092] Other particularly preferred monomeric polyisocyanate compounds are: diisocyanates such as 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- and 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1-polyisocyanato-3,3,5-trimethyl-5-polyisocyanatomethylcyclohexane (isophorone diisocyanate), 4,4'-diisocyanatodicyclohexylmethane, 2,4- and 2,6-diisocyanatomethylcyclohexane and mixtures thereof. In principle, aromatic polyisocyanates such as toluene diisocyanate or 4,4'-diisocyanatodiphenylmethane can also be used.

[0093] Other specific examples of diisocyanates include, for example, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), hydrogenated MDI (H12MDI), xylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXD1) 4,4'-diphenyldimethylmethane diisocyanate, dialkyl diphenylmethane diisocyanates and tetraalkyl diphenylmethane diisocyanates, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, isomers of toluene diisocyanate (TDI), (if applicable) in a mixture, 1-methyl-2,4-diisocyanatocyclohexane, 1,6-diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2,2,4-trimethylhexane, ester-2,4,4-trimethylhexane, 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane, chlorinated and brominated diisocyanates, phosphorus-containing diisocyanates, 4,4'-diisocyanatophenylperfluoroethane, tetramethoxybutane-1,4-diisocyanate, butane-1,4-diisocyanate, hexane-1,6-diisocyanate (HDI), dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, ethylene diisocyanate, ethyl phthalate diisocyanate, and polyisocyanates with reactive halogen atoms, such as 1-chloromethylphenyl-2,4-diisocyanate-1,1-bromomethylphenyl-2,6-diisocyanate, 3,3-bischloromethyl ether-4,4'-diphenyl diisocyanate.

[0094] Surprisingly, more stable capsule shells or capsule walls can be formed, in particular using long-chain aliphatic diisocyanates having 6, 7, 8, 9, 10 or even more carbon atoms.

[0095] In a particularly preferred embodiment, the inner non-aqueous phase comprises a mixture of two or more different polymerizable polyisocyanates, for example polyisocyanates having different chain lengths, which can form copolymers.

[0096] Derivatives of polyisocyanates which are preparable by modifying the abovementioned diisocyanates or mixtures thereof according to known methods and which contain, for example, uretdione, urethane, isocyanurate, biuret and / or allophanate groups can also be used in proportion in the process according to the invention.

[0097] Particular preference is given to combinations of at least two different, preferably aliphatic, polyisocyanates or combinations of at least one aliphatic and at least one aromatic polyisocyanate.

[0098] Such a combination takes advantage of the different reaction rates of polyisocyanates: aromatic polyisocyanates react significantly faster than aliphatic polyisocyanates, and short-chain aliphatic polyisocyanates, i.e., those having 1 to 5 carbon atoms, preferably 3 to 5 carbon atoms, react faster than long-chain analogs.

[0099] In another preferred embodiment of the invention, different aliphatic and / or aromatic polyisocyanates also have different chain lengths. In this context, long-chain polyisocyanates preferably have 6, 7, 8, 9, 10, 11, 12, 13, 14, 20, 25 or more carbon atoms, but more preferably have 6 to 12 carbon atoms, particularly preferably have 6 to 8 carbon atoms. Short-chain polyisocyanates are polyisocyanates having 1 to 5 carbon atoms, preferably polyisocyanates having 3 to 5 carbon atoms.

[0100] Preferred according to the present invention are combinations of short-chain aliphatic polyisocyanates (C1, C2, C3, C4, C5) and long-chain aliphatic polyisocyanates (C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C20, C25 or more), or short-chain aliphatic polyisocyanates (C1, C2, C3, C4, C5) (C1, C2, C3, C4, C5) and long-chain aromatic polyisocyanates (C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C20, C25 or more). C9, C10, C11, C12, C13, C14, C15, C20, C25 or more), or a combination of a long chain aliphatic polyisocyanate (C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C20, C25 or more) (C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C20, C25 or more) and a short chain aromatic polyisocyanate.

[0101] In this context, it is particularly preferred to use mixtures of different aliphatic polyisocyanates having two or more isocyanate groups with a chain length of 1 to 12 carbon atoms, preferably 3 to 8 carbon atoms, particularly preferably 4 to 7 carbon atoms in the chain, for the preparation of the microcapsules according to the invention.

[0102] In this regard, aliphatic polyisocyanates are particularly preferred due to their chemical relationship with bio-based systems. For example, lysine and 1,5-diisocyanopentane both show the same degradation product 1,5-diaminopentane and are therefore particularly suitable for the preparation of bio-based and biodegradable microcapsules from an environmental perspective.

[0103] The main embodiment includes mixtures of long-chain and short-chain diisocyanates in any ratio. Preferably, the mixing ratio of long-chain diisocyanate to short-chain diisocyanate is in the range of 4:1 to 1:4, particularly preferably in the range of 2:1 to 1:2.

[0104] Examples of preferred specific mixtures of at least one aliphatic polyisocyanate and at least one aromatic polyisocyanate are mixtures of the biuret of hexamethylene diisocyanate with a trimethylol adduct of xylene diisocyanate, mixtures of the biuret of hexamethylene diisocyanate with polyisocyanurates of diisocyanates or mixtures of the biuret of hexamethylene diisocyanate with a trimethylolpropane adduct of toluene diisocyanate.

[0105] Even more preferably according to the invention, in the above-mentioned combination of short-chain aliphatic polyisocyanates and long-chain aliphatic polyisocyanates, or in the combination of short-chain aliphatic polyisocyanates and long-chain aromatic polyisocyanates, or in the combination of long-chain aliphatic polyisocyanates and short-chain aromatic polyisocyanates, the polyisocyanates are present as a mixture in monomeric or oligomeric or polymeric form.

[0106] Preferably, for use in the method according to the invention, the following combination results:

[0107] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0108] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and long-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0109] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aromatic polyisocyanates (monomers or oligomers or polymers);

[0110] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and long-chain aromatic polyisocyanates (monomers or oligomers or polymers);

[0111] - long-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0112] - long-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and long-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0113] - long-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aromatic polyisocyanates (monomers or oligomers or polymers);

[0114] - long-chain aliphatic polyisocyanates (monomers) and long-chain aromatic polyisocyanates (oligomers or polymers);

[0115] The definitions of short and long chains described previously are used.

[0116] It can be observed that the selection of at least two aliphatic polyisocyanates of different chain length and degree of polymerization, or a mixture of aliphatic polyisocyanates and aromatic polyisocyanates, can significantly improve stability and performance (release of fragrance in the case of fragrance capsules) due to the differences in reaction time, dissociation and crosslinking structure of the polyisocyanate components.

[0117] The abovementioned polyisocyanate combinations or polyisocyanate mixtures consisting of two different aliphatic or one aliphatic and one aromatic polyisocyanate can be used to produce particularly stable and better, ie more densely branched, crosslinks in the capsule shell.

[0118] Thus, using the process described herein, high-performance (fragrance release) microcapsules can be prepared from mixtures of linear and aromatic polyisocyanates or from mixtures of two different linear polyisocyanates. Such microcapsules are very stable and are characterized by outstanding fragrance preservation properties, which in turn manifest themselves in better capsule performance (fragrance release), for example in the field of fragrance encapsulation.

[0119] The use of two different polyisocyanates produces microcapsules that again exceed the stability of microcapsules made from a single polyisocyanate system, as shown in the following examples.

[0120] As the following examples illustrate, microcapsules made from aliphatic-aliphatic polyisocyanate mixtures are just as good as microcapsules made from aliphatic-aromatic polyisocyanate mixtures. Therefore, in principle, combinations of at least two different polymerizable (preferably aliphatic and / or aromatic) polyisocyanates are preferred in the present invention.

[0121] The content of the polyisocyanate used for preparing the microcapsules according to the present invention is 0.1 to 10.0% by weight, preferably 0.5 to 3.0% by weight, relative to the total weight of the internal non-aqueous phase.

[0122] The ratio of the polyisocyanate component to the internal non-aqueous phase is preferably between 1:50 and 1:20, even more preferably between 1:40 and 1:30.

[0123] Due to the low content of polyisocyanate components, it is possible according to the invention to prepare polyurea / polyurethane microcapsules in which the absolute content of polyisocyanate is only 1 / 50 of the total capsule containing at least one lipophilic active substance to be encapsulated. Thus, the process according to the invention can prepare polyurea / polyurethane microcapsules whose polyisocyanate content is only 0.6% by weight relative to the total weight of the capsule wall. Preferably, the polyisocyanate content is about 1.8% by weight of the capsule wall. Despite the low content of polyisocyanate, the microcapsules according to the invention are distinguished by a high stability.

[0124] In step (a1) of the method for preparing microcapsules according to the invention, at least one polymerizable polyisocyanate containing at least two or more isocyanate functional groups together with at least one or more active substances to be encapsulated are first substantially dissolved in an inert non-aqueous solvent or a mixture of inert non-aqueous solvents. By "substantially dissolved", it is understood that at least 90% by weight, preferably at least 98% by weight, even more preferably 99.9% by weight of the above components are dissolved in the solvent or solvent mixture so that they can be used in the present method. More preferably, at least one polyisocyanate and at least one active substance to be encapsulated are completely dissolved in the solvent or solvent mixture. If the solvent does not ensure sufficient dissolution of the isocyanate, this disadvantage can be overcome by using a suitable dissolution promoter.

[0125] Preferred solvents for the inner non-aqueous phase are immiscible with water, non-reactive with the isocyanate component or reactive materials, and have little or no odor in the amounts used.

[0126] The term "solvent" as used herein includes all types of oil bodies or oil components, in particular vegetable oils (e.g. rapeseed oil, sunflower oil, soybean oil, olive oil and the like), modified vegetable oils (e.g. alkoxylated sunflower oil or soybean oil), synthetic (tri)glycerides (e.g. engineered mixtures of mono-, di- and triglycerides of C6 to C22 fatty acids), fatty acid alkyl esters (e.g. methyl or ethyl esters of vegetable oils), ME 18RD-F, ME18SD-F, ME 12C-F and ME1270), fatty acid alkyl esters based on these C6 to C22 fatty acids), mineral oils and mixtures thereof. Examples of suitable and preferred lipophilic solvents are: Guerbet alcohols based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, linear C6 to C22 fatty acid esters with linear or branched C6 to C22 fatty alcohols, or branched C6 to C13 carboxylic acid esters with linear or branched C6 to C22 fatty alcohols, for example myristyl myristate, myristyl palmitate, myristyl stearate, myristyl isostearate, myristyl oleate, myristyl behenate, myristyl erucate, cetyl myristate, cetyl palmitate, cetyl stearate, cetyl isostearate, cetyl oleate, cetyl behenate, cetyl erucate, stearyl myristate, stearyl palmitate Esters, stearyl stearate, stearyl isostearate, stearyl oleate, stearyl stearate, stearyl erucate, isostearyl myristate, isostearyl palmitate, isostearyl stearate, isostearyl isostearate, isostearyl oleate, isostearyl behenate, oleyl myristate, oleyl palmitate, oleyl stearate , oleyl isostearate, oleyl oleate, oleyl behenate, oleyl erucate, behenyl myristate, behenyl palmitate, behenyl stearate, behenyl isostearate, behenyl oleate, behenyl behenate, behenyl erucate, erucyl myristate, erucyl palmitate, erucyl stearate, erucyl isostearate, erucyl oleate, erucyl behenate and erucyl erucate.

[0127] Likewise suitable are esters of linear C6 to C22 fatty acids with branched alcohols, in particular 2-ethylhexanol, esters of C18 to C38 alkylhydroxycarboxylic acids with C6 to C22 linear or branched fatty acids, in particular dioctyl esters, esters of linear or branched fatty acids with polyols (e.g. propylene glycol, dimer diol or trimer triol) and / or Guerbet alcohols, triglycerides based on C6 to C10 fatty acids, liquid mono / di / triglyceride mixtures of C6 to C18 fatty acids, esters of C6 to C22 fatty alcohols and / or Guerbet alcohols with aromatic carboxylic acids, in particular benzoic acid, esters of C2 to C12 dicarboxylic acids with linear or branched alcohols having 1 to 22 carbon atoms or polyols having 2 to 10 carbon atoms and 2 to 6 hydroxyl groups, vegetable oils, branched primary alcohols, substituted cyclohexanes, linear or branched C6 to C22 fatty alcohol carbonates, such as dicaprylyl carbonate ( CC); Guerbet carbonates based on fatty alcohols having 6 to 18 carbon atoms, preferably 8 to 10 carbon atoms, benzoates with linear or branched C6 to C22 alcohols, linear or branched, symmetrical or asymmetrical dialkyl ethers such as dioctyl ether, each alkyl radical having 6 to 22 carbon atoms, ring-opening products of epoxidized fatty acid esters with polyols, silicone oils (cyclopolymethylsiloxanes, polysiloxanes of polymethylsiloxane grade etc.), aliphatic or cycloalkyl hydrocarbons, for example squalane, squalene or dialkylcyclohexanes and / or mineral oil.

[0128] In particular, preferred solvents are esters of linear C6 to C22 fatty acids with branched alcohols, esters of C18 to C38 alkylhydroxycarboxylic acids with C6 to C22 linear or branched fatty alcohols, linear or branched C6 to C22 fatty alcohols, in particular dioctyl malate, esters of linear or branched fatty acids with polyols such as propylene glycol, dimer diol or trimer triol and / or Guerbet alcohols, triglycerides based on C6 to C10 fatty acids, polyols based on C6 to C18 fatty acids, Liquid mono- / di- / triglyceride mixtures, esters of C6 to C22 fatty alcohols and / or Guerbet alcohols with aromatic carboxylic acids, in particular benzoic acid, esters of C2 to C12 dicarboxylic acids with linear or branched alcohols having 1 to 22 carbon atoms or polyols having 2 to 10 carbon atoms and 2 to 6 hydroxyl groups, vegetable oils, branched primary alcohols, substituted cyclohexanes, linear or branched C6 to C22 fatty alcohol carbonates, for example dioctyl carbonate (Cetiol TMCC), Guerbet carbonates based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, esters of benzoic acid with linear or branched C6 to C22 alcohols, linear or branched, symmetrical or asymmetrical dialkyl ethers having 6 to 22 carbon atoms per alkyl group, for example bisoctyl ether (Cetiol TM OE), ring-opening products of epoxidized fatty acid esters with polyols, silicone oils (cyclopolymethylsiloxanes and silicone methicones, etc.) and / or aliphatic or cycloalkanes, for example squalane, squalene or dialkylcyclohexanes.

[0129] In addition, within the scope of the present invention, liquid straight-chain and / or branched and / or saturated or unsaturated hydrocarbons or any desired mixtures thereof may be used as solvents. For example, the solvent may be an alkane having 4 to 22 carbon atoms, preferably 6 to 18 carbon atoms, or any mixture thereof.

[0130] Particularly advantageously, inert solvents suitable for use as the inner non-aqueous phase are: alkyl aromatics such as diisopropylnaphthalene or substituted biphenyls, chlorinated biphenyls, paraffins, chlorinated paraffins, natural vegetable oils (such as cottonseed oil, peanut oil and palm oil), tricresyl phosphates, silicone oils, dialkyl phthalates, dialkyl adipates, partially hydrogenated terphenyls, alkylated biphenyls, alkylated naphthalenes, diaryl ethers, aryl alkyl ethers and highly alkylated benzenes, benzyl benzoate, isopropyl myristate and any mixture of these hydrophobic solvents and mixtures of one or more of these hydrophobic solvents with kerosene, paraffin and / or isoparaffins. Preferably, vegetable oils (such as sunflower oil), triglycerides, benzyl benzoate or isopropyl myristate are used as solvents for providing the inner non-aqueous phase.

[0131] The abovementioned solvents are used in the process according to the invention either individually or as a mixture of two or more solvents.

[0132] In an alternative and preferred variant of the process according to the invention, at least one polyisocyanate is dissolved directly in a solution of at least one active substance, preferably one or more fragrances or flavorings / fragrances or flavorings or fragrance oils, so that essentially no solvents as described above are present in the core of the microcapsules according to the invention. In this regard, avoiding the use of solvents in the microcapsule core is advantageous for reducing manufacturing costs and for environmental reasons.

[0133] In particular, the fragrance or flavoring agent is dissolved in a solvent commonly used in the fragrance or flavoring industry. Preferably, the solvent is not an alcohol, since alcohols react with isocyanates. Examples of suitable solvents are diethyl phthalate, isopropyl myristate, (rosin resin, available from Eastman), benzyl benzoate, ethyl citrate, limonene or other terpenes or isoparaffins. Preferably, the solvent is highly hydrophobic. Preferably, the fragrance or flavoring solution contains less than 30% solvent. More preferably, the fragrance or flavoring solution contains less than 20% solvent, even more preferably less than 10% solvent, wherein all these percentages are defined by weight relative to the total weight of the fragrance or flavoring solution. Most preferred are fragrances or flavorings that are substantially free of solvent.

[0134] In principle, any material suitable for encapsulation in microcapsules can be used as the active substance to be encapsulated or the core material for preparing the microcapsules according to the invention. The active material to be encapsulated is a lipophilic, water-insoluble or water-immiscible liquid or solid as well as a suspension.

[0135] At least one of the active substances to be encapsulated used in the method according to the invention is a lipophilic active substance. This ensures that during the preparation of the microcapsules according to the invention, the active substance to be encapsulated is in the inner non-aqueous phase and does not mix with the outer aqueous phase, otherwise no emulsion can be formed and no capsule wall material can be deposited on the surface of the droplets. This results in the lipophilic active substance being completely encapsulated in the microcapsules as core material during the subsequent emulsification and crosslinking of the capsule wall components. The inner non-aqueous phase thus formed is characterized by having organic hydrophobic and oily characteristics.

[0136] In a particularly preferred variant of the invention, at least one lipophilic or hydrophobic active substance is, in particular, a lipophilic or hydrophobic fragrance or flavoring, or a lipophilic or hydrophobic perfume oil or essence (fragrance or flavoring mixture), a cooling agent, a TRPV1 or TRPV3 modulator, a substance that causes a pungent taste or a hot or warm sensation on the skin or mucous membranes, or a substance that causes a tingling or stinging sensation in the mouth or throat, or an active substance with a pungent or spicy or astringent effect, a pesticide, a biocide, an insecticide, a substance from the class of insect repellents, a food additive, a cosmetic active substance, a pharmaceutical active substance, a dye, a dye precursor, a fluorescent dye, an agrochemical, an optical brightener, a solvent, a wax, a silicone oil, a lubricant, a paper printing coating substance, or a mixture of two or more of the above active substances.

[0137] In a preferred variant of the invention, the lipophilic active ingredient is in particular a lipophilic fragrance or a fragrance mixture consisting of two or more fragrances (fragrance oils), or a flavoring or a flavoring mixture consisting of two or more flavorings (essences) or a biotin.

[0138] Particularly preferably, the core comprises one or more aromatics or flavoring agents selected from the group consisting of extracts of natural raw materials and fractions thereof or components isolated therefrom; individual aromatics from the hydrocarbon class; fatty alcohols; fatty aldehydes and acetals; fatty ketones and oxime compounds; aliphatic sulfur-containing compounds; aliphatic nitriles; fatty carboxylic acid esters; formates, acetates, propionates, isobutyrates, butyrates, isovalerates, valerates, hexanoates, crotonates, tiglic acid esters and 3-methyl-2-butenoic acid esters of acyclic terpene alcohols; acyclic terpene aldehydes and ketones and their dimethyl and diethyl acetals; formates, acetates, propionates, isobutyrates, butyrates, isovalerates, valerates, hexanoates, crotonates, tiglic acid esters and 3-methyl-2-butenoic acid esters of cyclic terpene alcohols , propionates, isobutyrates, butyrates, isovalerates, valerates, hexanoates, crotonates, tiglic acid esters and 3-methyl-2-butenoate; cyclic terpene aldehydes and ketones; cyclic alcohols; cyclic ethers and alicyclic ethers; cyclic ketones and macrocyclic ketones; alicyclic aldehydes; alicyclic ketones; cyclic alcohol esters; alicyclic alcohol esters; alicyclic carboxylic acid esters; aromatic hydrocarbons; alicyclic alcohols; esters of alicyclic alcohols and aliphatic carboxylic acids; alicyclic ethers; aromatic aldehydes and alicyclic aldehydes; aromatic and aliphatic ketones; aromatic and aliphatic carboxylic acids and their esters; nitrogen-containing aromatic compounds; phenyl ethers and phenyl esters; heterocyclic compounds; lactones; and mixtures of the above active substances, wherein the shell is completely or substantially impermeable to the fragrance.

[0139] Suitable fragrances and flavors for the manufacture of capsules according to the invention are preferably described, for example, in Steffen Arctander, "Riechstoffe [Fragrances]", "Perfume and Flavor Chemicals", self-published, Montclair, NJ, 1969; H. Surburg, J. Panten, "Common Fragrance and Flavor Materials", Wiley-VCH, Weinheim, 2006, 5th edition.

[0140] Preferably, the microcapsules according to the present invention comprise a core material in the form of a hydrophobic single aroma or single flavor, wherein the core material comprises at least one single aroma or single flavor selected from one or more of the following groups:

[0141] - hydrocarbons, such as 3-carene; α-pinene; β-pinene; α-terpinene; γ-terpinene; p-cymene; bisabolene; camphene; caryophyllene; cedrene; farnesene; limonene; longifolene; myrcene; ocimene; valenciaene; (E,Z)-1,3,5-undecatriene; styrene; diphenylmethane;

[0142] - fatty alcohols, such as hexanol; octanol; 3-octanol; 2,6-dimethylheptanol; 2-methylheptanol; 2-methyloctanol; (E)-2-hexenol; (E) and (Z)-3-hexenol; 1-octen-3-ol; a mixture of 3,4,5,6,6-pentamethyl-3,4-hepten-2-ol and 3,5,6,6-tetramethyl-4-methyleneheptan-2-ol; (E,Z)-2,6-nonadienol; 3,7-dimethyl-7-methoxyoctan-2-ol; 9-decenol; 10-undecanol; 4-methyl-3-decen-5-ol;

[0143] - fatty aldehydes and their acetals, such as hexanal; heptanal; octanal; nonanal; decanal; undecanal; dodecanal; tridecanal; 2-methyloctanal; 2-methylnonanal; (E)-2-hexenal; (Z)-4-heptenal; 2,6-dimethyl-5-heptenal; 10-undecenal; (E)-4-decenal; 2-dodecenal; 2,6,10-trimethyl-5,9-undecadienal; heptaldehyde diethyl acetal; 1,1-dimethoxy-2,2,5-trimethyl-4-hexene; citronelloloxyacetaldehyde; 1-(1-methoxy-propoxy)-(E / Z)-3-hexene;

[0144] - Aliphatic ketones and their oxime compounds, such as 2-heptanone; 2-octanone; 3-octanone; 2-nonanone; 5-methyl-3-heptanone; 5-methyl-3-heptanone oxime; 2,4,4,7-tetramethyl-6-octen-3-one; 6-methyl-5-hepten-2-one;

[0145] - Aliphatic sulfur compounds, such as 3-methylthiohexanol; 3-methylthiohexyl acetate; 3-mercaptohexanol; 3-mercaptohexyl acetate; 3-mercaptohexyl butyrate; 3-acetylthiohexyl acetate; 1-menthene-8-thiol;

[0146] - Aliphatic nitriles, such as 2-nonenoic acid nitrile; 2-tridecenoic acid nitrile; 2,12-tridecenoic acid nitrile; 3,7-dimethyl-2,6-octadienoic acid nitrile; 3,7-dimethyl-6-octenoic acid nitrile;

[0147] - fatty carboxylic acids and esters thereof, such as (E)- and (Z)-3-hexenyl carboxylate; ethyl acetoacetate; isoamyl acetate; hexyl acetate; 3,5,5-trimethylhexyl acetate; 3-methyl-2-butylene acetate; (E)-2-hexenyl acetate; (E)-3-hexenyl acetate; octyl acetate; 3-octyl acetate; 1-octene-3-acetate; ethyl butyrate; butyl butyrate; isoamyl butyrate; hexyl butyrate; (E) and (Z)-3-hexenyl acetate; Alkenyl isobutyrate; hexyl crotonate; ethyl isovalerate; ethyl 2-methylvalerate; ethyl hexanoate; allyl hexanoate; ethyl heptanoate; allyl heptanoate; ethyl octanoate; ethyl (E,Z)-2,4-decadienoate; in particular ethyl 2-trans-4-cis-decadienoate; methyl 2-octanoate; methyl 2-nonanoate; allyl-2-isopentyloxyacetate; methyl 3,7-dimethyl-2,6-octadienoate; 4-methyl-2-pentyl crotonate;

[0148] - acyclic terpene alcohols, such as citronellol; geraniol; nerol; linalool; lavandulol; nerolidol; farnesol; tetrahydrolinalool; tetrahydrogeraniol; 2,6-dimethyl-7-octen-2-ol; 2,6-dimethyloctan-2-ol; 2-methyl-6-methylene-7-octen-2-ol; 2,6-dimethyl-5,7-octadien-2-ol; 2,6-dimethyl-3,5-octadien-2-ol; 3,7-dimethyl-4,6-octadien-3-ol; 3,7-dimethyl-1,5,7-octatrien-3-ol; 2,6-dimethyl-2,5,7-octatrien-1-ol; and their formates, acetates, propionates, isobutyrates, butyrates, isovalerates, valerates, hexanoates, crotonates, tiglic acid esters and 3-methyl-2-butenoate esters;

[0149] - acyclic terpene aldehydes and ketones, such as geranial; neral; citronellal; 7-hydroxy-3,7-dimethyloctanal; 7-methoxy-3,7-dimethyloctanal; 2,6,10-trimethyl-9-undecenal; geranyl acetone; and the dimethyl and diethyl acetals of geranial, neral and 7-hydroxy-3,7-dimethyloctanal; in particular the dimethyl and diethyl acetals of geranial, neral and 7-hydroxy-3,7-dimethyloctanal;

[0150] - cyclic terpene alcohols, such as menthol; isopulegol; α-terpineol; terpineol-4; menthane-8-ol; menthane-1-ol; menthane-7-ol; borneol; isoborneol; linalool oxide; nopol; cedrol; ambroxanol; vetiverol; guaiacol; and their formates, acetates, propionates, isobutyrates, butyrates, isovalerates, valerates, hexanoates, crotonates, tiglic acid esters and 3-methyl-2-butenoate esters;

[0151] -Cyclic terpene aldehydes and ketones, such as menthone; isomenthone; 8-mercaptomenthan-3-one; carvone; camphor; fenchone; α-ionone; β-ionone; α-n-methylionone; β-n-methylionone; α-isomethylionone; β-isomethylionone; α-irone; β-irone; α-damascenone; β-damascenone; γ-damascenone; δ-damascenone; γ-damascenone; 1-(2,4,4-trimethyl-2-cyclohexen-1-yl)-2-butane 1-ene-1-one; 1,3,4,6,7,8a-hexahydro-1,1,5,5-tetramethyl-2H-2,4a-methylenenaphthalene-8-(5H)-one; 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butenal; nootkatone; dihydronobutanone; 4,6,8-megastigmatrien-3-one; α-sweet orange aldehyde; β-sweet orange aldehyde; acetylated cedar oil (methyl cedar ketone);

[0152] -Cyclic alcohols, such as 4-tert-butyl cyclohexanol; 3,3,5-trimethylcyclohexanol; 3-isobornylcyclohexanol; 2,6,9-trimethyl-(Z2,Z5,E9)-cyclododecantrien-1-ol; 2-isobutyl-4-methyltetrahydro-2H-pyran-4-ol; alicyclic alcohols, such as 3,3,3-trimethylcyclohexylmethanol; 2-methyl-4-(2,2,3-trimethyl-3-cyclopent-1-yl)butanol; 2-methyl-4-(2,2,3-trimethyl-3-cyclopent-1-yl)-2-butene-1-ol; 2-ethyl-4- (2,2,3-trimethyl-3-cyclopent-1-yl)-2-butene-1-ol; 3-methyl-5-(2,2,3-trimethyl-3-cyclopent-1-yl)-pentane-2-ol; 3-methyl-5-(2,2,3-trimethyl-3-cyclopent-1-yl)-4-pentene-2-ol; 3,3-dimethyl-5-(2,2,3-trimethyl-3-cyclopent-1-yl)-4-pentene-2-ol; 1-(2,2,6-trimethylcyclohexyl)pentane-3-ol; 1-(2,2,6-trimethylcyclohexyl)hexane-3-ol;

[0153] - Cyclic and alicyclic ethers, such as eucalyptol; cedarwood methyl ether; cyclododecyl methyl ether; 1,1-dimethoxycyclododecane; (ethoxymethoxy)cyclododecane; α-epoxycedrene; 3a,6,6,9a-tetramethyldodecahydronaphtho[2,1-b]furan; 3a-ethyl-6,6,9a-trimethyldodecahydronaphtho[2,1-b]furan; 1,5,9-trimethyl-13-oxabicyclo[10.1.0]tridecyl-4,8-diene; rose oxide; 2-(2,4-dimethyl-3-cyclohexen-1-yl)-5-methyl-5-(1-methylpropyl)-1,3-dioxane;

[0154] - Cyclic ketones and macrocyclic ketones, such as 4-tert-butylcyclohexanone; 2,2,5-trimethyl-5-pentylcyclopentanone; 2-heptylcyclopentanone; 2-pentylcyclopentanone; 2-hydroxy-3-methyl-2-cyclopenten-1-one; 3-methyl cis-2-penten-1-yl-2-cyclopenten-1-one; 3-methyl-2-pentyl-2-cyclopenten-1-one; 3-methyl-4-cyclopentadecenone; 3-methyl-5-cyclopentadecenone; 3-hydroxy-3-methyl ... -methylcyclopentadecanone; 4-(1-ethoxyvinyl)-3,3,5,5-tetramethylcyclohexanone; 4-tert-pentylcyclohexanone; 5-cyclohexadecene-1-one; 6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)indanone; 8-cyclohexadecene-1-one; 7-cyclohexadecene-1-one; (7 / 8)-cyclohexadecene-1-one; 9-cycloheptadecene-1-one; cyclopentadecanone; cyclohexadecane-1-one;

[0155] - cycloaliphatic aldehydes, such as 2,4-dimethyl-3-cyclohexenecarboxaldehyde; 2-methyl-4-(2,2,6-trimethyl-cyclohexen-1-yl)-2-butenal; 4-(4-hydroxy-4-methylpentyl)-3-cyclohexenecarboxaldehyde; 4-(4-methyl-3-penten-1-yl)-3-cyclohexenecarboxaldehyde;

[0156] - cycloaliphatic ketones, such as 1-(3,3-dimethylcyclohexyl)-4-penten-1-one; 2,2-dimethyl-1-(2,4-dimethyl-3-cyclohexen-1-yl)-1-propanone; 1-(5,5-dimethyl-2-cyclohexen-1-yl)-4-penten-1-one; 2,3,8,8-tetramethyl-1,2,3,4,5,6,7,8-octahydro-2-naphthylmethyl ketone; methyl-2,6,10-trimethyl-2,5,9-cyclododecantrienyl ketone; tert-butyl (2,4-dimethyl-3-cyclohexen-1-yl) ketone;

[0157] -esters of cyclic alcohols, such as 2-tert-butyl cyclohexyl acetate; 4-tert-butyl cyclohexyl acetate; 2-tert-amyl cyclohexyl acetate; 4-tert-amyl cyclohexyl acetate; 3,3,5-trimethyl cyclohexyl acetate; decahydro-2-naphthyl acetate; 2-cyclopentylcyclopentyl crotonate; 3-pentyltetrahydro-2H-pyran-4-acetate; decahydro-2,5,5,8a-tetramethyl-2-naphthyl acetate; 4 ,7-methano-3a,4,5,6,7,7a hexahydro-5- or -6-indenyl acetate; 4,7-methano-3a,4,5,6,7,7a hexahydro-5- or -6-indenyl propionate; 4,7-methano-3a,4,5,6,7,7a hexahydro-5- or -6-indenyl isobutyrate; 4,7-methano-octahydro-5- or -6-indenyl acetate;

[0158] - esters of cycloaliphatic alcohols, such as 1-cyclohexylethyl crotonate;

[0159] - Esters of cycloaliphatic carboxylic acids, such as allyl-3-cyclohexyl propionate; allyl cyclohexyloxyacetate; cis- and trans-methyl dihydrojasmonate; cis- and trans-methyl jasmonate; methyl 2-hexyl 3-oxocyclopentanecarboxylate; ethyl 2-ethyl-6,6-dimethyl-2-cyclohexenecarboxylate; ethyl 2,3,6,6-tetramethyl-2-cyclohexenecarboxylate; ethyl 2-methyl-1,3-dioxolane-2-acetate;

[0160] - Aromatic hydrocarbons, such as styrene and diphenylmethane;

[0161] - fatty alcohols, such as benzyl alcohol; 1-phenylethanol; 2-phenylethanol; 3-phenylpropanol; 2-phenylpropanol; 2-phenoxyethanol; 2,2-dimethyl-3-phenylpropanol; 2,2-dimethyl-3-(3-methylphenyl)propanol; 1,1-dimethyl-2-phenylethanol; 1,1-dimethyl-3-phenylpropanol; 1-ethyl-1-methyl-3-phenylpropanol; 2-methyl-5-phenylpentanol; 3-methyl-5-phenylpentanol; 3-phenyl-2-propen-1-ol; 4-methoxybenzyl alcohol; 1-(4-isopropylphenyl)ethanol;

[0162] - Esters of aromatic aliphatic alcohols and fatty carboxylic acids, such as benzyl acetate; benzyl propionate; benzyl isobutyrate; benzyl isovalerate; ethyl 2-phenylacetate; 2-phenylethyl propionate; 2-phenylethyl isobutyrate; 2-phenylethyl isovalerate; ethyl 1-phenylacetate; α-trichloromethylbenzyl acetate; α,α-dimethylphenylethyl acetate; α,α-dimethylphenylethyl butyrate; cinnamyl acetate; ethyl 2-phenoxyisobutyrate; 4-methoxybenzyl acetate;

[0163] - aromatic aliphatic ethers, such as 2-phenylethyl methyl ether; 2-phenylethyl isoamyl ether; 2-phenylethyl-1-ethoxyethyl ether; phenylacetaldehyde dimethyl acetal; phenylacetaldehyde diethyl acetal; hydrogenated atroaldehyde dimethyl acetal; phenylacetaldehyde glycerol acetal; 2,4,6-trimethyl-4-phenyl-1,3-dioxane; 4,4a,5,9b-tetrahydroindeno[1,2-d]m-dioxin; 4,4a,5,9b-tetrahydro-2,4-dimethylindeno[1,2-d]m-dioxin;

[0164] - aromatic and aromatic aliphatic aldehydes, such as benzaldehyde; phenylacetaldehyde; 3-phenylpropanal; hydroataldehyde; 4-methylbenzaldehyde; 4-methylphenylacetaldehyde; 3-(4-ethylphenyl)-2,2-dimethylpropanal; 2-methyl-3-(4-isopropylphenyl)propanal; 2-methyl-3-(4-tert-butylphenyl)propanal; 3-(4-tert-butylphenyl)propanal; cinnamaldehyde; α-butylcinnamaldehyde; α-amylcinnamaldehyde; α-hexylcinnamaldehyde; 3-methyl-5-phenylpentanal; 4-methoxybenzaldehyde; 4-hydroxy-3-methoxybenzaldehyde; 4-hydroxy-3-ethoxybenzaldehyde; 3,4-methylenedioxybenzaldehyde; 3,4-dimethoxybenzaldehyde; 2-methyl-3-(4-methoxyphenyl)propanal; 2-methyl-3-(4-methylenedioxyphenyl)propanal;

[0165] - aromatic and araliphatic ketones, such as acetophenone; 4-methylacetophenone; 4-methoxyacetophenone; 4-tert-butyl-2,6-dimethylacetophenone; 4-phenyl-2-butanone; 4-(4-hydroxyphenyl)-2-butanone; 1-(2-naphthyl)ethanone; benzophenone; 1,1,2,3,3,6-hexamethyl-5-indenylmethyl ketone; 6-tert-butyl-1,1-dimethyl-4-indenylmethyl ketone; 1-[2,3-dihydro-1,1,2,6-tetramethyl-3-(1-methylethyl)-1H-5-indenyl]ethanone; 5',6',7',8'-tetrahydro-3',5',5',6',8',8'-hexamethyl-2-naphthylacetonone;

[0166] - aromatic and araliphatic carboxylic acids and their esters, such as benzoic acid; phenylacetic acid; methyl benzoate; ethyl benzoate; hexyl benzoate; benzyl benzoate; methyl phenylacetate; ethyl phenylacetate; geranyl phenylacetate; phenylethyl phenylacetate; methyl cinnamate; ethyl cinnamate; benzyl cinnamate; phenylethyl cinnamate; cinnamyl cinnamate; allylphenoxyacetate; methyl salicylate; isopentyl salicylate; hexyl salicylate; cyclohexyl salicylate; cis-3-hexenyl salicylate; benzyl salicylate; phenylethyl salicylate; methyl 2,4-dihydroxy-3,6-dimethylbenzoate; ethyl 3-phenylglycidate; ethyl 3-methyl-3-phenylglycidate;

[0167] - nitrogen-containing aromatic compounds, such as 2,4,6-trinitro-1,3-dimethyl-5-tert-butylbenzene; 3,5-dinitro-2,6-dimethyl-4-tert-butylacetophenone; cinnamic acid nitrile; 5-phenyl-3-methyl-2-pentanoic acid nitrile; 5-phenyl-3-methylpentanoic acid nitrile; methyl anthranilate; methyl N-methyl anthranilate; Schiff bases of methyl anthranilate with 7-hydroxy-3,7-dimethyloctanal, 2-methyl-3-(4-tert-butyl-phenyl)propanal or 2,4-dimethyl-3-cyclohexenecarboxaldehyde; 6-isopropylquinoline; 6-isobutylquinoline; 6-sec-butylquinoline; indole; skatole; 2-methoxy-3-isopropylpyrazine; 2-isobutyl-3-methoxypyrazine; 4-(4,8-dimethyl-3,7-nonadienyl)pyridine;

[0168] -phenols, phenyl ethers and phenyl esters, such as estragol (tarragol); anethole; eugenol; eugenol methyl ether; isoeugenol; isoeugenol methyl ether; thymol; carvacrol; diphenyl ether; β-naphthyl methyl ether; β-naphthyl ethyl ether; β-naphthyl isobutyl ether; 1,4-dimethoxybenzene; eugenol acetate; 2-methoxy-4-methylphenol; 2-ethoxy-5-(1-propenyl)phenol; p-tolylphenyl acetate; from the group of heterocyclic compounds, such as 2,5-dimethyl-4-hydroxy-2H-furan-3-one; 2-ethyl-4-hydroxy-5-methyl-2H-furan-3-one; 3-hydroxy-2-methyl-4H-pyran-4-one; 2-ethyl-3-hydroxy-4H-pyran-4-one;

[0169] -lactones, such as 1,4-octanolactone; 3-methyl-1,4-octanolactone; 1,4-nonanolactone; 1,4-decanolactone; 8-decene-1,4-lactone; 1,4-undecanolactone; 1,4-dodecanolactone; 1,5-decanolactone; 1,5-dodecanolactone; 1,15-pentadecanolactone; cis- and trans-11-pentadecen-1,15-lactone; cis- and trans-12-pentadecen-1,15-lactone; 1,16-hexadecanolactone; 9-hexadecene-1,16 -lactone; 10-oxa-1,16-hexadecanolide; 11-oxa-1,16-hexadecanolide; 12-oxa-1,16-hexadecanolide; ethylene-1,12-dodecanedioate; ethylene-1,13-tridecanedioate; coumarin; 2,3-dihydrocoumarin; octahydrocoumarin; and stereoisomers, enantiomers, positional isomers, diastereomers, cis / trans isomers or diastereomers of the above substances; and mixtures of the above substances.

[0170] In another variant of the method according to the invention, the flavorings can also be encapsulated in the form of individual flavorings as a core material, wherein the core material comprises as active substance at least one individual flavoring or a mixture thereof.

[0171] Typical examples of flavoring agents or fragrances that can be encapsulated within the meaning of the present invention are selected from the group consisting of: acetophenone; allyl hexanoate; α-ionone; β-ionone; anisaldehyde; anisyl acetate; anisyl formate; benzaldehyde; benzothiazole; benzyl acetate; benzyl alcohol; benzyl benzoate; β-ionone; butyl butyrate; butyl hexanoate; butylidenephthalide; carvone; camphene; caryophyllene; eucalyptol; cinnamyl acetate; citral; citronellol; citronellal; citronellyl acetate; cyclohexyl acetate; cymene; damascena; ketone; decalactone; dihydrocoumarin; dimethyl anthranilate; dimethyl anthranilate; dodecalactone; ethoxyethyl acetate; ethyl butyric acid; ethyl butyrate; ethyl decanoate; ethyl caproate; ethyl crotonate; ethyl furanone; ethyl guaiacol; ethyl isobutyrate; ethyl isovalerate; ethyl lactate; ethyl methylbutyrate; ethyl propionate; eucalyptol; eugenol; ethyl heptanoate; 4-(p-hydroxyphenyl)-2-butanone; γ-decalactone; geraniol; geranyl acetate; geranyl acetate; viniferal; methyl dihydrojasmonate (e.g. ); heliotropin; 2-heptanone; 3-heptanone; 4-heptanone; trans-2-heptenal; cis-4-heptenal; trans-2-hexenal; cis-3-hexenol; trans-2-hexenoic acid; trans-3-hexenoic acid; cis-2-hexenyl acetate; cis-3-hexenyl acetate; cis-3-hexenyl hexanoate; trans-2-hexenyl hexanoate; cis-3-hexenyl formate; cis-2-hexyl acetate; cis-3-hexyl acetate; trans-2-hexyl acetate; cis-3-hexyl formate; p-hydroxybenzylacetone; isopentanol; isopentanyl isovalerate; isobutyl butyrate; isobutyraldehyde; isoeugenol methyl ether; isopropyl methylthiazole; lauric acid; levulinic acid; linalool; linalool oxide; linalyl acetate; menthol; menthol furan; methyl anthranilate; methyl butanol; methyl butyric acid; methyl butyl acetate 2-; methyl caproate; methyl cinnamate; 5-methyl furfural; 3,2,2-methylcyclopentenolone; 6,5,2-methylheptenone; methyl dihydrojasmonate; methyl jasmonate; 2-methylbutyrate; 2-methyl-2-pentenoic acid; methyl thiobutyrate; 3,1-methylthiohexanol; 3-methylthiohexyl acetate; nerol; neryl acetate; trans, trans-2,4-nonadienal; 2,4-nonadienol; 2,6-nonadienol; 2,4-nonadienol; nootkatone; δ-octalactone; γ-octalactone; 2-octanol; 3-octanol; 1,3-octenol; 1-octyl acetate; 3-octyl acetate; palmitic acid; trimeraldehyde; phellandrene; pentyl diketone; phenethyl acetate; phenethyl alcohol; phenethyl isovalerate; piperonal; propionaldehyde; propyl butyrate; longleaf mint; pulegol; sweet orange aldehyde; thiothiazole; terpinene; terpineol; terpinolene; 8,3-thiomenthone; 4,4,2-thiomethylpentanone; thymol; δ-undecalactone; γ-undecalactone; valencene; valeric acid; vanillin; acetoin; ethyl vanillin; ethyl vanillin isobutyrate (3-ethoxy-4-isobutyryloxybenzaldehyde); 2,5-dimethyl-4-hydroxy-3(2H)-furanone and its derivatives (preferably cyclohomofuranone (2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone), homofuranone (2-ethyl-5-methyl-4-hydroxy-3(2H)- furanone and 5-ethyl-2-methyl-4-hydroxy-3(2H)-furanone); maltol and maltol derivatives (preferably ethyl maltol); coumarin and coumarin derivatives; γ-lactones (preferably γ-undecalactone, γ-nonalactone, γ-decanolactone); δ-lactones (preferably 4-methylδ-decanolactone, masonolactone, δ-decanolactone, Tuberolacton); methyl sorbate; divanillin; 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)furanone; 2-hydroxy-3-methyl-2-cyclopentenone; 3-hydroxy-4,5-dimethyl-2(5H)furanone; isoamyl acetate; ethyl butyrate; n-butyl butyrate; isoamyl butyrate; ethyl 3-methylbutyrate; ethyl n-hexanoate;Allyl hexanoate; n-butyl hexanoate; ethyl octanoate; ethyl 3-methyl 3-phenyl glycidate; ethyl 2-trans-4-cis-decadienoate; 4-(p-hydroxyphenyl)-2-butanone; 1,1-dimethoxy-2,2,5-trimethyl-4-hexane; 2,6-dimethyl-5-heptene-1-al; phenylacetaldehyde; 2-methyl-3-(methylthio)furan; 2-methyl-3-furanthiol; bis(2-methyl) -3-furanyl) disulfide; furfurylthiol; methylthiopropionaldehyde; 2-acetyl-2-thiazoline; 3-mercapto-2-pentanone; 2,5-dimethyl-3-furanthiol; 2,4,5-trimethylthiazole; 2-acetylthiazole; 2,4-dimethyl-5-ethylthiazole; 2-acetyl-1-pyrroline; 2-methyl-3-ethylpyrazine; 2-ethyl-3,5-dimethylpyrazine; 2-ethyl-3,6-dimethylpyrazine ; 2,3-diethyl-5-methylpyrazine; 3-isopropyl-2-methoxypyrazine; 3-isobutyl-2-methoxypyrazine; 2-acetylpyrazine; 2-pentylpyridine; (E,E)-2,4-decadienal; (E,E)-2,4-nonadienal; (E)-2-octenal; (E)-2-nonenal; 2-undecenal; 12-methyltridecal; 1-penten-3-one; 4-hydroxy-2,5-dimethyl -3(2H)furanone; guaiacol; 3-hydroxy-4,5-dimethyl-2(5H)-furanone; 3-hydroxy-4-methyl-5-ethyl-2(5H)-furanone; cinnamaldehyde; cinnamyl alcohol; methyl salicylate; isopulegol and stereoisomers, enantiomers, positional isomers, diastereomers and cis / trans isomers or epimers of the above substances not explicitly mentioned herein; and mixtures of the above substances. ;

[0172] Among the above-mentioned individual fragrances which can be encapsulated within the meaning of the present invention, preference is given to using fragrances having aldehyde, carboxylic acid or ester functions.

[0173] Aldehyde fragrances (which also include the corresponding acetals, esters and lactones) can be divided into the following categories, namely

[0174] (i) fatty aldehydes and their acetals;

[0175] (ii) alicyclic aldehydes;

[0176] (iii) aromatic aldehydes or aromatic aliphatic aldehydes;

[0177] (iv) aliphatic, aromatic or araliphatic esters; and

[0178] (v) lactones;

[0179] and mixtures thereof.

[0180] The above-mentioned fragrances having aldehyde, carboxylic acid or ester functions and mixtures thereof are selected from one or more of the following groups:

[0181] - fatty aldehydes and their acetals, such as hexanal; heptanal; octanal; nonanal; decanal; undecanal; dodecanal; tridecanal; 2-methyloctanal; 2-methylnonanal; (f)-2-hexenal; (Z)-4-heptenal; 2,6-dimethyl-5-heptenal; 10-undecenal; (f)-4-decenal; 2-dodecenal; 2,6,10-trimethyl-5,9-undecadienal; heptaldehyde diethyl acetal; 1,1-dimethoxy-2,2,5-trimethyl-4-hexene; citronellyloxyacetaldehyde;

[0182] - cycloaliphatic aldehydes, such as 2,4-dimethyl-3-cyclohexenecarboxaldehyde; 2-methyl-4-(2,2,6-trimethyl-cyclohexen-1-yl)-2-butenal; 4-(4-hydroxy-4-methylpentyl)-3-cyclohexenecarboxaldehyde; 4-(4-methyl-3-penten-1-yl)-3-cyclohexenecarboxaldehyde;

[0183] - aromatic and aliphatic aldehydes, such as benzaldehyde; phenylacetaldehyde; 3-phenylpropanol; hydroataldehyde; 4-methylbenzaldehyde; 4-methylphenylacetaldehyde; 3-(4-ethylphenyl)-2,2-dimethylpropanal; 2-methyl-3-(4-isopropylphenyl)-propanal; 2-methyl-3-(4-tert-butylphenyl)propanal; 3-(4-tert-butylphenyl)propanal; cinnamaldehyde; α-butylcinnamaldehyde; α-amylcinnamaldehyde; α-hexylcinnamaldehyde; 3-methyl-5-phenylpentanal; 4-methoxybenzaldehyde; 4-hydroxy-3-methoxybenzaldehyde; 4-hydroxy-3-ethoxybenzaldehyde; 3,4-methylenedioxybenzaldehyde; 3,4-dimethoxybenzaldehyde; 2-methyl-3-(4-methoxyphenyl)-propanal; 2-methyl-3-(4-methylenedioxyphenyl)-propanal;

[0184] - fatty carboxylic acid esters, such as (E)- and (Z)-3-hexenyl carboxylate; ethyl acetoacetate; isoamyl acetate; hexyl acetate; 3,5,5-trimethylhexyl acetate; 3-methyl-2-butylene acetate; (f)-2-hexenyl acetate; (E) and (Z)-3-hexenyl acetate; octyl acetate; 3-octyl acetate; 1-octene-3-acetate; ethyl butyrate; butyl butyrate; isoamyl butyrate Esters; hexyl butyrate; (E) and (Z)-3-isobutyrate hexenyl esters; hexyl crotonate; ethyl isovalerate; ethyl 2-methylpentanoate; ethyl hexanoate; allyl hexanoate; ethyl heptanoate; allyl heptanoate; ethyl octanoate; ethyl (E,Z)-2,4-decadienoate; methyl 2-octanoate; methyl 2-nonanoate; allyl 2-isopentyloxyacetate; methyl 3,7-dimethyl-2,6-octadienoate;

[0185] -esters of cyclic alcohols, such as 2-tert-butylcyclohexyl acetate; 4-tert-butylcyclohexyl acetate; 2-ieri-pentylcyclohexyl acetate; 4-tert-pentylcyclohexyl acetate; decahydro-2-naphthyl acetate; 3-pentyltetrahydro-2- / - / -pyran-4-yl acetate; decahydro-2,5,5,8a-tetramethyl-2-naphthyl acetate; 4,7-methano-3a,4,5,6,7,7a-hexahydro-5- or -6-indenyl acetate; 4,7-methano-3a,4,5,6,7,7a-hexahydro-5- or -6-indenyl propionate; 4,7-methano-3a,4,5,6,7,7a-hexahydro-5- or -6-indenyl isobutyrate; 4,7-methanooctahydro-5- or -6-indenyl acetate;

[0186] - Esters of aromatic alcohols and fatty carboxylic acids, such as benzyl acetate; benzyl propionate; benzyl isobutyrate; benzyl isovalerate; 2-phenylethyl acetate; 2-phenylethyl propionate; 2-phenylethyl isobutyrate; 2-phenylethyl isovalerate; 1-phenylethyl acetate; α-trichloromethylbenzyl acetate; α,α-dimethylphenylethyl acetate; α,α-dimethylphenylethyl butyrate; cinnamyl acetate; 2-phenoxyethyl isobutyrate; 4-methoxybenzyl acetate;

[0187] - Esters of alicyclic carboxylic acids, such as allyl-3-cyclohexyl propionate; allyl cyclohexyloxyacetate; methyl dihydrojasmonate; methyl jasmonate; methyl 2-hexyl-3-oxocyclopentanecarboxylate; ethyl 2-ethyl-6,6-dimethyl-2-cyclohexenecarboxylate; ethyl 2,3,6,6-tetramethyl-2-cyclohexenecarboxylate; ethyl 2-methyl-1,3-dioxolane-2-acetate;

[0188] - aromatic and araliphatic carboxylic acid esters, such as methyl benzoate; ethyl benzoate; hexyl benzoate; benzyl benzoate; methyl phenylacetate; ethyl phenylacetate; geranyl phenylacetate; phenylethyl phenylacetate; methyl cinnamate; ethyl cinnamate; benzyl cinnamate; phenylethyl cinnamate; cinnamyl cinnamate; allylphenoxyacetate; methyl salicylate; isopentyl salicylate; hexyl salicylate; cyclohexyl salicylate; cis-3-hexenyl salicylate; benzyl salicylate; phenylethyl salicylate; methyl 2,4-dihydroxy-3,6-dimethylbenzoate; ethyl 3-phenylglycidate; ethyl 3-methyl-3-phenylglycidate.

[0189] The following lists aldehydes, acetals, esters and lactones and their commercial names which are particularly preferred as representatives of groups (i) to (v) for the purposes of the process according to the invention:

[0190] Aldehydes: 2-methylvaleraldehyde; Aldehyde C12 MNAHM; Aldehyde C4; Aldehyde C5; Aldehyde C6; Aldehyde C7; Aldehyde C8; Aldehyde C9; Aldehyde C10; Aldehyde C11ISO; Aldehyde C11 MOA pure; Undehyde C11; Aldehyde C 11UNDEYLENIC; Aldehyde C12; Aldehyde C12MNA; Aldehyde C13; Citronaldehyde; Amylcinnamaldehyde α; Anisealdehyde-O; Anisealdehyde; Natural Benzaldehyde; Bergamotaldehyde; Boric aldehyde; Bojie Red Aldehyde; Camphoraldehyde; Citral; Citronellal HM; Citronelloloxyacetaldehyde; Citral (CITRYLAL); CITROYLAL E HM; Phenoxyacetaldehyde; Phenoxyacetaldehyde 50PCT PEMOSA; crotonaldehyde; cuminaldehyde; cyclamenaldehyde; decanal trans, trans-2,4, cis-4 decanal; trans-2 decanal; natural trans-2 decanal; trans-4 decanal; decanal-9,1; dodecenal-2,6; trans-2 dodecanal; DUPICAL; 10% triepoxy decanal-4,5-2; ethylhexanal; Cyanide aldehyde; Geranial; Heliopan; Heliopan; Heliotropin; Heptadienal trans, trans, 2-4; Cis-4-heptenal; Trans-2-heptenal; Trans-2-hexenal; Hexylcinnamaldehyde α; Solanum nigrum aldehyde; Hydroxycitronellal; INTRELEVEN ALDEHYDE SPEC.; Isononanal; Isovaleraldehyde; Citral H&R JS I; Lilial; LINOLAL; Lilial; MAJANTAL; MANDRINAL; Mandarin 10% TEC BHT; Mavranal; METHODY Citronellal; Methylbutyraldehyde; Methylcinnamaldehyde α; Methylphenylpentenal 4,2,2; Methylthiopropionaldehyde-3; Methyltridecane-12 10% VT; Methyl-3-butene-2-aldehyde; Methyl-5-phenyl-2-hexene-2-aldehyde; MUGENAL 50DPG; Neocyclocitral; Nonadienal; Trans, cis-2,6; Cis-6 Nonenal; Trans-2 Nonenal; 3 / 060251; trans-2-pentenal; perillaldehyde; phenylacetaldehyde; phenylbutenal trans-2,2; phenylpropanal; PINOACET ALDEHYDE; PROFRANESAL; propionaldehyde 2-(p-tolyl); propionaldehyde; PS-IRALDEINXNEU; safranal; salicylaldehyde FG; silver aldehyde (SILVIAL); tetrahydrocitral; cis-2,2; p-tolualdehyde FG; tridecenal trans-2; trifeRNAL; undecadienal-2,4; trans-2-undecenal; VERNALALDEHYDE; VERTOCITRAL; VERTOMUGAL; VERTIPRENAL; VETRAL ROH; natural cinnamaldehyde HM; acetals: FLOROPAL; heptaldehyde diethyl acetal; nonadienal diethyl acetal; OKOUMAL; phenylacetaldehyde glycerol acetal; phenylacetaldehyde dimethyl acetal; esters: jasmine pyran; jasmonate; methyl dihydrojasmonate;

[0191] In another alternative embodiment, in the polyurea / polyurethane microcapsules according to the invention, a fragrance mixture or a fragrance oil or a flavoring mixture or a flavoring is used as the active substance to be encapsulated or the core material. These are compositions containing at least one fragrance or flavoring, which can be used to make such a fragrance oil or essence. Such compositions, in particular a flavoring mixture or a fragrance oil, preferably contain 2, 3, 4, 5, 6, 7, 8, 9, 10 or more flavorings. Preferably, the fragrance mixture or perfume oil is selected from the group consisting of extracts of natural raw materials; essential oils, extracts, absolutes, resins, resinoids, balsams, tinctures, such as ambergris tincture; ambergris oil; angelica seed oil; angelica root oil; anise oil; perilla oil; valerian oil; basil oil; tree moss absolute; laurel oil; artemisia oil; benzoin resin; bergamot oil; beeswax absolute; birch tar; bitter almond oil; savory oil; basil leaf oil; cabreuva oil; juniper berry oil; calamus oil; camphor oil; cananga oil; cardamom oil; quinoa oil; cinnamon oil; acacia absolute; castoreum absolute; cedar leaf oil; cedarwood oil; labdanum oil; citronella oil; lemon oil; copaiva balsam balsam; copaiba balsam oil; coriander oil; costus vulgaris root oil; cumin oil; cypress oil; davana oil; dill weed oil; dill seed oil; eau de brouts absolute; oakmoss absolute; elemi oil; tarragon oil; lemon eucalyptus oil; eucalyptus oil; fennel oil; spruce needle oil; fir needle oil; galbanum oil; galbanum resin; geranium oil; grapefruit oil; guaiac wood oil; guarana balsam; guarana balsam oil; helichrysum absolute; helichrysum oil; ginger oil; orris root absolute; orris root oil; jasmine absolute; calamus oil; chamomile oil blue; Roman chamomile oil; carrot Oil of pine needles; oil of curly mint; oil of coriander; oil of labdanum; absolute oil of labdanum; resin of labdanum; absolute oil of lavender; absolute oil of lavender; absolute oil of lavender; oil of lavender; oil of lemongrass; oil of lovage; oil of white lemon distilled; oil of white lemon pressed; oil of camphor; oil of litsea cubeba; oil of laurel; oil of laurel leaf; oil of mace; oil of marjoram; oil of orange; oil of Massoi bark bark oil; mimosa absolute; Musk grain oil; Musk tincture; Muscat sage oil; nutmeg seed oil; myrrh absolute; myrrh oil; myrtle oil; clove leaf oil; clove flower oil; neroli oil; frankincense absolute; frankincense oil; parsnip root oil; neroli absolute; orange oil; oregano oil; palmarosa oil; patchouli oil; basil oil; Peru balsam oil; parsley leaf oil; parsley seed oil; petitgrain oil; mint oil; pepper oil; allspice oil; pine oil; poley oil; rose absolute; rosewood oil; rose oil; rosemary oil; Dalmatian sage oil; Spanish sage oil; sandalwood oil;Celery seed oil; Spicy lavender oil; Star anise oil; Styrax oil; Marigold oil; Fir needle oil; Tea tree oil; Turpentine oil; Thyme oil; Tolu balsam; Tonka bean absolute; Tuberose absolute; Vanilla extract; Violet leaf absolute; Verbena oil; Vetiver oil; Juniper berry oil; Wine yeast oil; Wormwood oil; Wintergreen oil; Ylang-ylang oil; Hyssop oil; Civet absolute; Cinnamon leaf oil; Cassia bark oil and fractions thereof or components isolated therefrom.

[0192] Exemplary cooling agents useful as lipophilic active substances in the preparation of microcapsules according to the present invention include one or more menthol and menthol derivatives (e.g., L-menthol, D-menthol, racemic menthol, isomenthol, neoisomenthol, neomenthol), menthyl ethers (e.g., (1-menthoxy)-2-propanediol, (1-menthoxy)-2-methyl-1,2-propanediol, 1-menthyl methyl ether), menthyl esters (e.g., menthyl formate, menthyl acetate, menthyl isobutyrate), menthyl esters (e.g., menthyl esters ... Menthyl acetate, menthyl lactate, L-menthyl L-lactate, L-menthyl D-lactate, (2-methoxy) menthyl acetate, (2-methoxyethoxy) menthyl acetate, menthyl pyroglutamate), menthyl carbonate (e.g., propylene glycol menthyl carbonate, ethylene glycol menthyl carbonate, glyceryl menthyl carbonate or a mixture thereof), half esters of menthol and dicarboxylic acids or derivatives thereof (e.g., monomenthyl succinate, monomenthyl glutarate, monomenthyl malonate, o-menthyl succinate-N,N -(dimethyl)amide, succinic acid o-menthyl ester amide), menthyl carboxylic acid amides (e.g. menthyl carboxylic acid N-acetamide [WS3], N-α-(methanecarbonyl)glycine ethyl ester [WS5], menthyl carboxylic acid N-(4-cyanophenyl)amide, menthyl carboxylic acid N-(alkoxyalkyl)amide), menthone and menthone derivatives (e.g. L-menthone glycerol ketal), 2,3-dimethyl-2-(2-propyl)butyric acid derivatives (e.g. 2,3-dimethyl-2-(2-propyl)butyric acid derivatives (e.g. 2,3-dimethyl-2-(2-propyl)butyric acid derivatives [WS23]), isopulegol or its esters (1-(-)isopulegol, 1-(-)isopulegol acetate), menthane derivatives (e.g. p-menthane 3,8-diol), cubebol or synthetic or natural mixtures containing cubebol, pyrrolidine derivatives of cycloalkyldione derivatives (e.g. 3-methyl)-2-(1-pyrrolidinyl)-2-cyclopenten-1-one) or tetrahydropyrimidin-2-one (e.g. Icilin or related compounds described in WO 2004 / 026840). Other cooling agents are menthol (L-menthol, D-menthol, racemic menthol, isomenthol, neoisomenthol, neomenthol), L-menthyl methyl ether, menthyl formate, menthyl acetate, menthone, isopulegol, L-(-)-isopulegol acetate) and cubebol, which have a taste effect. Suitable cooling agents are well known in the art and are described, for example, in US 2017 / 216802 (A1), US 2010 / 273887 (A1), EP 2 033 688 (A2) and EP 1 958627 (A2).

[0193] In another variant, TRPV1 and TRPV3 modulators are used as active substances or core materials to be encapsulated in the polyurea / polyurethane microcapsules according to the present invention. TRPV1 and TRPV3 modulators are known in the prior art and are related to TRP (transient receptor potential) channels of the vanilloid (TRPV) subfamily. TRPV1 modulators impart the spicy taste and heat sensation associated with capsaicin and piperine. TRPV3 proteins belong to a family of non-selective cation channels that play a role in various processes, including temperature sensation and vascular regulation. TRPV3 channels can be directly activated by a variety of natural compounds (such as carvacrol, thymol and eugenol). Some other monoterpenoid compounds that either cause a sensation of heat or are skin sensitizers can also open the channel. Monoterpenoid compounds can also induce agonist-specific desensitization of TRPV3 channels in a calcium-independent manner.

[0194] In another variant, active substances are used as active substances to be encapsulated or as core material in the polyurea / polyurethane microcapsules according to the invention, which are selected from the group consisting of substances that cause a pungent taste or a hot or warm sensation on the skin or mucous membranes, or substances that cause a tingling sensation in the mouth or throat, or substances with a stimulating or pungent or astringent effect.

[0195] Preferably, the active substance causing a sensation of heat or irritation (pyrogenic agent) is selected from the group consisting of red pepper powder, chili powder, red pepper extract, pepper extract, pepper extract, ginger root extract, paradise pepper extract (Aframomum melegueta), Spilanthes extract (Spilanthes acmella or Spilanthes oleracea), Japanese pepper extract (Zanthoxylum piperitum), Kaempferia extract, Galanga extract, Water pepper extract (Polygonium hydropiper), capsaicinoids, in particular capsaicin, dihydrocapsaicin or nonanamide; gingerols, in particular gingerol-[6], gingerol-[8] or gingerol-

[10] ; shogaols, in particular shogaol-[6], shogaol-[8], shogaol-

[10] ; gingerdiones, in particular gingerdione-[6], gingerdione-[8] or gingerdione-

[10] ; paradoles, in particular gingerdione-[6], gingerdione-[8] or gingerdione-

[10] ; dehydrogingerdiones, in particular dehydrogingerdione-[6], dehydrogingerdione-[8] or dehydrogingerdione-

[10] ; piperine; piperine derivatives; ethyl 2-(4-hydroxy-3-methoxy-phenyl)acetate and 3-phenylpropyl-2-(4-hydroxy-3-methoxy-phenyl)acetate and mixtures thereof.

[0196] Preferably, the active substance perceived as irritating or pungent is selected from the group consisting of aromatic isothiocyanates, in particular phenethyl isothiocyanate, allyl isothiocyanate, cyclopropyl isothiocyanate, butyl isothiocyanate, 3-methylthiopropyl isothiocyanate, 4-hydroxybenzyl isothiocyanate, 4-methoxybenzyl isothiocyanate and mixtures thereof.

[0197] Preferably, the tingling active substance is selected from the group consisting of: 2E,4E-decadienoic acid-N-isobutylamide (trans-serrulate chrysanthemum lysine), in particular as described in WO 2004 / 043906; 2E,4Z-decadienoic acid-N-isobutylamide (cis-serrulate chrysanthemum lysine), in particular as described in WO 2004 / 043906; Described in 2004 / 000787; 2Z,4Z-decadienoic acid-N-isobutylamide; 2Z,4E-decadienoic acid-N-isobutylamide; 2E,4E-decadienoic acid-N-([2S]-2-methylbutyl)amide; 2E,4E-decadienoic acid-N-([2S]-2-methylbutyl)amide; 2E,4E-decadienoic acid-N-([2R]-2-methylbutylamide); 2E,4Z-decadienoic acid-N-(2-methylbutyl)amide; 2E,4E-decadienoic acid-N-piperidinamide (achilleamide); 2E,4E-decadienoic acid-N-piperidinamide (sarmentin); 2E-decenoic acid-N-isobutyramide; 3E-decenoic acid-N-isobutyramide; 3E-nonenoic acid-N-isobutyramide; 2E,6Z,8E-decetrienoic acid-N-isobutyramide (spilantholamide); 2E,6Z,8E-decetrienoic acid-N-([2S]-2-methylbutyl)amide (homospilantholamide); 2E,6Z,8E-decetrienoic acid-N-([2R]-2-methylbutyl)amide; 2E-decene-4-acid-N-isobutyramide; 2Z-decene-4-ynoic acid-N-isobutyramide; 2E,6Z,8E,10E-dodecanedione 2E,6Z,8E,10E-docotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide (α-hydroxy sanshool); 2E,6E,8E,10E-docotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide (γ-hydroxy sanshool); 2E,4E,8Z,10E,12E-tetradecotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide (γ-hydroxy sanshool); 2E,4E,8E,10E,12E-tetradecotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide 2E,4E,8Z,10E,12E-tetradecanoic acid-N-(2-methyl-2-propenyl)amide (γ-dehydrosanshool); 2E,4E,8Z,10E,12E-tetradecanoic acid-N-(2-methylpropyl)amide (γ-sanshool); 2E,4E,8Z,11Z-tetradecanoic acid-N-(2-hydroxy-2-methylpropyl)amide (bungeanool); 2E,4E,8Z,11E-tetradecanoic acid-N-(2-hydroxy-2-methylpropyl)amide (isosanshool);2E,4E,8Z-tetradecadienoic acid-N-(2-hydroxy-2-methylpropyl)amide (dihydrozanthoxylum bungeanum) and 2E,4E-tetradecadienoic acid-N-(2-hydroxy-2-methylpropyl)amide (tetrahydrozanthoxylum bungeanum) and mixtures thereof. ;

[0198] Preferably, the active substance having astringent action is chosen from the group consisting of catechins, in particular epicatechin, gallocatechin, epigallocatechin and their respective gallates, in particular epigallocatechin gallate or epicatechin gallate, their oligomers (proanthocyanidins, proanthocyanidins, prodelphinidin, procyanidin, thearubigenin, theagallin) and their C- and O-glycosides; dihydroflavonoids, such as dihydromyricetin, taxifolin and their C- and O-glycosides, flavonols, such as myricetin, quercetin and its C- and O-glycosides, such as quercetin, rutin, gallic acid esters of carbohydrates, such as tannins, pentagalloyl glucose or reaction products thereof, such as elligatannin, aluminum salts, such as alum, and mixtures thereof.

[0199] In another variant of the method according to the invention, the biogenin can also be encapsulated as a core material, wherein the core material comprises at least one biogenin or a mixture thereof.

[0200] Biogenics refers to active substances with biological activity, such as tocopherol, tocopheryl acetate, tocopheryl palmitate, ascorbic acid, carnotine, carnosine, caffeine, (deoxy)ribonucleic acid and its cleavage products, β-glucan, retinol, bisabolol, allantoin, phytotriol, panthenol, AHA acid, amino acids, ceramides, pseudoceramides, essential oils, plant extracts and vitamin complexes.

[0201] In another variant of the method according to the invention, paper printing coating substances are also used as active substances to be encapsulated or as core materials, as described in US Pat. No. 2,800,457 A, the relevant disclosure of which is hereby fully incorporated into the present description by reference.

[0202] The content of the lipophilic active substance or the lipophilic active substance mixture used for preparing the microcapsules according to the invention is 90.0 to 99.9% by weight, preferably 97.0 to 99.5% by weight, relative to the total weight of the inner non-aqueous phase.

[0203] The ratio of active substance(s) to internal non-aqueous phase is preferably between 50:1 and 20:1, even more preferably between 40:1 and 30:1.

[0204] Thus, by means of the process according to the invention, a high loading of active substance in the microcapsules according to the invention can be achieved.

[0205] Furthermore, the first polymerization and / or crosslinking step of the process according to the invention comprises providing an external aqueous phase comprising at least one protective colloid and optionally at least one emulsifier (a2).

[0206] For this purpose, the protective colloid and the emulsifier are dissolved in an external aqueous phase, preferably in an aqueous solvent. Suitable solvents are water or a mixture of water and at least one water-soluble organic solvent. Suitable organic solvents are, for example, glycerol, 1,2-propylene glycol, 1,3-propylene glycol, ethylene glycol, diethylene glycol, triethylene glycol and other analogs. However, the preferred solvent is water.

[0207] A protective colloid is a polymer system which prevents the aggregation (agglomeration, coagulation and flocculation) of the emulsified, suspended or dispersed components in a suspension or dispersion. During solvation, the protective colloid binds large amounts of water and produces high viscosities in aqueous solutions, depending on the concentration. During the preparation of oil-in-water emulsions, the protective colloid attaches itself to the primary particles using its hydrophobic part and diverts its polar (i.e. hydrophilic) molecular part towards the aqueous phase. By this attachment at the interface, the protective colloid reduces the interfacial tension and prevents the aggregation of the primary particles. In addition, the protective colloid stabilizes the emulsion, in this case promoting the formation of relatively small droplets and thus also the corresponding microcapsules.

[0208] In the context of the method according to the invention, the protective colloid has, in addition to the above-mentioned properties, emulsifying properties. If the protective colloid (e.g. carboxymethylcellulose, acid-modified starch, polyvinyl alcohol, ammonium salt derivatives of polyvinyl alcohol, polystyrene sulfonates, polyvinyl pyrrolidone, polyvinyl acrylate, etc.) has sufficient emulsifying properties, then in the method according to the invention it is even advantageously possible to dispense with the use of emulsifiers.

[0209] The protective colloid used in the process according to the invention is selected from the group consisting of:

[0210] - diols, in particular ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, isobutylene glycols, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol, 1,2-dodecanediol, and

[0211] polyols, preferably triols, in particular glycerol and its ethoxylation and propoxylation products, trimethylolpropane and its ethoxylation and propoxylation products; polyvinyl alcohol (PVOH) and its derivatives, in particular ammonium- or sulfonate-functionalized polyvinyl alcohol; polyphenols, preferably 1,3,5-trihydroxybenzene; polysaccharides, in particular glucose, starch or chemically, mechanically and / or enzymatically modified starch, cellulose derivatives, such as hydroxyethylcellulose, in particular quaternized hydroxyethylcellulose and carboxymethylcellulose,

[0212] - Polyvinyl pyrrolidone, maleic acid vinyl copolymer, sodium lignin sulfonate, maleic anhydride / styrene copolymer, ethylene / maleic anhydride copolymer, copolymer of ethylene oxide, propylene oxide and polyethoxylated sorbitan ester, sodium lauryl sulfate,

[0213] - Animal and vegetable polymers, in particular gum arabic (Senegal and Seyir types), proteins, gelatin, mastic, shellac, lignin, chitosan, saponins

[0214] and mixtures of the above compounds.

[0215] Preferably, the external aqueous phase contains at least one protective colloid selected from polyvinyl pyrrolidone, polyvinyl alcohol and mixtures thereof. Polyvinyl pyrrolidone is particularly preferred. The molecular weight of commercial standard polyvinyl pyrrolidone is in the range of about 2500 to 750000 g / mol. Particularly preferably, polyvinyl alcohol or its ammonium salt derivatives, 1,3,5-trihydroxybenzene or starch, in particular modified starch, or animal or plant polymers are used as protective colloids to prepare microcapsules according to the invention.

[0216] Starch, in particular modified starch, or animal or plant polymers are natural biodegradable substances. In combination with the polyisocyanates described herein, the present method can thus provide bio-based and biodegradable capsule shells. Therefore, in the method according to the invention, starch and animal and plant polymers also play the role of so-called biocrosslinking agents.

[0217] The starch used in the process according to the invention is selected from the group consisting of corn starch, potato starch, rye starch, wheat starch, barley starch, oat starch, rice starch, pea starch, tapioca starch and mixtures thereof.

[0218] The chemically modified starch is preferably acid-modified starch, alkali-modified starch, oxidized starch, acetylated starch, succinate-ated starch or octenylsuccinate-ated starch.

[0219] According to the invention, combinations of two or more different protective colloids as described above can also be used to prepare the microcapsules according to the invention.

[0220] It has been found to be particularly advantageous in the process according to the invention to use a combination of one of the abovementioned protective colloids with starch or modified starch as the further protective colloid in the external aqueous phase. Due to the large number of hydroxyl groups, this combination stabilizes the emulsion and, on the other hand, favors the reaction between the protective colloid and the polyisocyanate, wherein in the reaction of the protective colloid with the polyisocyanate, the reaction equilibrium is shifted towards the product, i.e. the polyurethane. The large number of hydroxyl groups in the starch also enables particularly pronounced crosslinking to be formed sterically.

[0221] Depending on the number of functional groups and / or the size of the protective colloid, the above-mentioned protective colloids have different reaction rates with the isocyanate groups of at least one polyisocyanate. For example, due to its size, glycerol (for example compared to starch) reacts faster with isocyanate groups. Thus, by selecting the protective colloid, the crosslinking of the protective colloid with the isocyanate groups of the polyisocyanate can be controlled.

[0222] The combination of glycerol with starch or with modified starch, or glycerol with quaternized hydroxyethylcellulose or gum arabic of the Seychelles type, has proven to be a particularly advantageous combination. This combination exploits the above-mentioned properties of the two protective colloids: on the one hand the high reaction rate of glycerol and on the other hand the number of polymerizable functional groups of the other protective colloid.

[0223] The protective colloids used in the process according to the invention have a dual function. On the one hand, they act as protective colloids and thus, as described above, prevent agglomeration of the emulsified, suspended or dispersed components, stabilize the subsequently formed emulsion, promote the formation of small droplets, and stabilize the microcapsule dispersion finally formed.

[0224] On the other hand, due to the polymerizable properties, such as functional groups, in particular hydroxyl groups, the protective colloid crosslinks with at least one or more polyisocyanates during the polymerization process. By crosslinking with at least one polyisocyanate, a polymer layer is formed already in the emulsification step (a3), which contributes to the construction of the capsule wall or capsule shell and becomes its solid component.

[0225] Surprisingly, it has been found that when the inner non-aqueous phase is emulsified or suspended in the outer aqueous phase in the presence of a protective colloid (preferably a polyol), crosslinks near the core are formed at the interface between the emulsified or suspended oil droplets of active substance to be encapsulated (which form the core of the microcapsules according to the invention) and the outer external phase by interfacial polymerization. The crosslinking is based on the polyaddition reaction of polyisocyanates with the protective colloid (preferably a polyol) to form a capsule shell or capsule wall made of polyurethane, the equation of which is as follows:

[0226] n O=C=NR 1 -N=C=O+n HO-R 2 -OH-→(-R 2 -O-CO-NH-R 1 -NH-CO-O-) n

[0227] This is manifested in the production of gas and the release of carbon dioxide.

[0228] By forming the polymer layer already in the emulsification step, the active substances to be encapsulated, in particular active substances with aldehyde, carboxylic acid or ester functions, are protected so that, if necessary, deprotonation, oxidation or saponification, in particular in subsequent process steps, is prevented or at least minimized, thereby reducing or eliminating the loss of lipophilic active substances. These degradation products usually lead to instability of the emulsion.

[0229] According to the present invention, the ratio of the amount of protective colloid(s) used to the aqueous phase is preferably in the range of 1:50 to 1:10, and more preferably in the range of 1:40 to 1:30.

[0230] The ratio of protective colloid in the external aqueous phase to polyisocyanate in the internal non-aqueous phase is in the range of 1:5 to 1:2, preferably in the range of 1:2 to 1:1.

[0231] Thus, the amount of protective colloid or combination of protective colloids used is in the range of 1 to 8 wt. %, preferably in the range of 2 to 4 wt. %, even more preferably in the range of 3 to 4 wt. %, relative to the total weight of the external aqueous phase.

[0232] At least one protective colloid may, but need not, be part of the capsule shell. In particular, a protective colloid having a higher reactivity as described above will react faster or more readily with the isocyanate groups of the polyisocyanate component to form polyurethane crosslinking units which form part of the capsule shell or capsule wall and are present in an amount of 0.1 to a maximum of 15% by weight, but preferably 1 to 5% by weight, even more preferably 1.5 to 3% by weight, relative to the weight of the capsule.

[0233] In order to facilitate the formation of an emulsion consisting of an inner non-aqueous phase and an outer aqueous phase, to stabilize the emulsion formed and to prevent the separation of the inner non-aqueous (oily / organic / hydrophobic) phase and the outer aqueous (hydrophilic) phase, in the method according to the invention, an emulsifier or an emulsifying auxiliary is optionally added to the outer aqueous phase. If the protective colloid has no or only low (i.e. insufficient) emulsifying properties, an emulsifier is optionally added. If a protective colloid with an emulsifying effect is used, the use of an emulsifier can advantageously be avoided.

[0234] In the process according to the invention, preferably an O / W emulsifier is used as emulsifier, which can evenly distribute the oil droplets of the inner non-aqueous phase in the outer aqueous phase and stabilize the emulsion. The same applies to mixing solid insoluble active substances in the outer aqueous phase to stabilize the suspension obtained thereby.

[0235] For example, suitable emulsifiers are nonionic surfactants from at least one of the following groups:

[0236] - addition products of 2 to 30 mol of ethylene oxide and / or 0 to 5 mol of propylene oxide with linear fatty alcohols having 8 to 22 carbon atoms, with fatty acids having 12 to 22 carbon atoms, with alkylphenols having 8 to 15 carbon atoms in the alkyl group and with alkylamines having 8 to 22 carbon atoms in the alkyl group;

[0237] - alkyl and / or alkenyl oligoglycosides having 8 to 22 carbon atoms in the alkyl(en)yl residue and ethoxylated analogs thereof;

[0238] - addition products of 1 to 15 mol of ethylene oxide onto castor oil and / or hydrogenated castor oil;

[0239] - addition products of 15 to 60 mol of ethylene oxide onto castor oil and / or hydrogenated castor oil;

[0240] - partial esters of glycerol and / or sorbitan with unsaturated linear or saturated branched fatty acids having 12 to 22 carbon atoms and / or hydroxycarboxylic acids having 3 to 18 carbon atoms and adducts thereof with 1 to 30 mol of ethylene oxide;

[0241] - partial esters of polyglycerol (average degree of self-condensation 2 to 8), polyethylene glycol (molecular weight 400 to 5000), trimethylolpropane, pentaerythritol, sugar alcohols (such as sorbitol), alkyl glucosides (such as methyl glucoside, butyl glucoside and dodecyl glucoside), polyglucosides (such as cellulose) with saturated and / or unsaturated linear or branched fatty acids having 12 to 22 carbon atoms and / or hydroxycarboxylic acids having 3 to 18 carbon atoms, and their adducts with 1 to 30 mol of ethylene oxide, preferably

[0242] - mixed esters of pentaerythritol, fatty acids, citric acid and fatty alcohols and / or mixed esters of fatty acids having 6 to 22 carbon atoms, methyl glucose and polyols, preferably glycerol or polyglycerol;

[0243] - mono-, di- and tri-alkyl phosphates and mono-, di- and / or tri-ethylene glycol alkyl phosphates and their salts;

[0244] -Wool wax alcohol;

[0245] - polysiloxane-polyalkyl-polyether copolymers and their derivatives; block copolymers, such as polyethylene glycol-30 dipolyhydroxystearate; polymer emulsifiers, such as Goodrich's Pemulen types (TR-1, TR-2) or Cognis' SP;

[0246] - Polyalkylene glycols and glycerol carbonate.

[0247] Typical anionic emulsifiers which can be used in the process according to the invention for preparing isocyanate-based microcapsules are aliphatic fatty acids having 12 to 22 carbon atoms, such as palmitic acid, stearic acid or behenic acid, and dicarboxylic acids having 12 to 22 carbon atoms, such as azelaic acid or sebacic acid.

[0248] In addition, in the method for preparing isocyanate-based microcapsules according to the present invention, zwitterionic surfactants can be used as emulsifiers. Zwitterionic surfactants are surface-active compounds that carry at least one quaternary ammonium group and at least one carboxylate and one sulfonate in the molecule. Particularly suitable zwitterionic surfactants are so-called betaines, such as N-alkyl-N, N-dimethyl ammonium glycinate (e.g. coconut oil alkyl dimethyl ammonium glycinate), N-acylaminopropyl-N, N-dimethyl ammonium glycinate (e.g. coconut oil acylaminopropyl dimethyl ammonium glycinate) and 2-alkyl-3-carboxylmethyl-3-hydroxyethyl imidazoline and coconut oil acylaminoethyl hydroxyethyl carboxymethyl glycinate each having 8 to 18 carbon atoms in the alkyl or acyl group. Particularly preferred are fatty acid amide derivatives, whose CTFA name is cocamidopropyl betaine.

[0249] Amphoteric surfactants are also suitable emulsifiers. Amphoteric surfactants are surface-active compounds that contain at least one free amino group and at least one carboxyl group (-COOH) or sulfonic acid group (-SO3H) in addition to the C8 / 18 alkyl or acyl group in the molecule and can form inner salts. Examples of suitable amphoteric surfactants are N-alkylglycine, N-alkylpropionic acid, N-alkylaminobutyric acid, N-alkyliminodipropionic acid, N-hydroxyethyl-N-alkylamidopropylglycine, N-alkyltaurine, N-alkylsarcosine, 2-alkylaminopropionic acid and alkylaminoacetic acid, each having about 8 to 18 carbon atoms in the alkyl group. Particularly preferred amphoteric surfactants are N-coconut alkylaminopropionate, cocoacylaminoethylaminopropionate and C12 / 18-acylsarcosine.

[0250] Finally, cationic surfactants can also be used as emulsifiers, among which in particular those of the esterquat type, preferably methyl quaternized difatty acid triethanolamine ester salts, quaternized hydroxyethylcellulose, chitosan modified with propylene glycol and quaternized with epichlorohydrin, distearyldimethylammonium chloride (DSDMAC), benzalkonium chloride, benzethonium chloride, cetyl ammonium chloride, cetylpyridinium chloride, cetyltrimethylammonium bromide (cetrimonium bromide), dequalinium chloride.

[0251] The emulsifier may be added to the external aqueous phase in an amount of about 0.5 to about 10 wt %, and preferably about 1 to about 5 wt %, each relative to the total weight of the external aqueous phase.

[0252] The aqueous protective colloid-emulsifier solution is preferably prepared under stirring by adding the protective colloid and the emulsifier successively to the external aqueous phase (or vice versa), or by adding the protective colloid and the emulsifier simultaneously to the external aqueous phase.

[0253] It may be advantageous, for the preparation of the polyurea / polyurethane microcapsules according to the invention, that the external aqueous phase optionally contains a stabilizer dissolved or dispersed to prevent separation of the internal non-aqueous phase (oil phase) and the external aqueous phase.

[0254] Preferred stabilizers for the preparation of isocyanate-based microcapsules according to the invention are primarily acrylic acid copolymers with sulfonate groups. Also suitable are copolymers of acrylamide and acrylic acid, copolymers of alkyl acrylates and N-vinyl pyrrolidone, such as K15, K30 or K90 (BASF); sodium polycarboxylate, sodium polystyrene sulfonate, vinyl and methyl vinyl ether-maleic anhydride copolymers and ethylene, isobutylene or styrene-maleic anhydride copolymers, microcrystalline cellulose (commercially available, for example, as name), diutan gum, xanthan gum or carboxymethyl cellulose.

[0255] The stabilizers may be used in an amount in the range of 0.01 to 10% by weight, in particular in the range of 0.1 to 3% by weight, each relative to the external aqueous phase.

[0256] In the method according to the invention, the oil-in-water emulsion is prepared by mixing (a3) ​​an internal non-aqueous phase and an external aqueous phase. The weight ratio of the internal non-aqueous phase to the external aqueous phase is preferably in the range of 2:1 to 1:10, more preferably in the range of 1:2 to 1:4.

[0257] Under high turbulence or strong shear, liquid active substances form emulsions or, in the case of solid active substances, suspensions, i.e. an inner non-aqueous or oil phase is emulsified or suspended in an outer aqueous or hydrophilic phase. The diameter of the resulting microcapsules can be specifically adjusted by the intensity of the turbulence or shear. The droplet size can be checked by light scattering measurements or microscopy. In this case, the preparation of microcapsules can be continuous or discontinuous. With increasing viscosity of the aqueous phase or decreasing viscosity of the oil phase, the size of the resulting capsules generally decreases.

[0258] The process according to the invention for preparing polyurea / polyurethane microcapsules can be carried out, for example, by forced metering pumps using "inline" technology or else in conventional dispersing or emulsifying apparatuses with stirring.

[0259] The internal non-aqueous phase is emulsified or dispersed into the external aqueous phase by means of an emulsifying turbine (IKA Eurostar 20 high-speed stirrer) to prepare the microcapsules according to the present invention. The emulsification process in step (a3) ​​of the method according to the present invention is advantageously carried out at a stirring speed of 1000 to 5000 rpm, preferably 3000 to 4000 rpm, for 30 seconds to 20 minutes, preferably 1 to 4 minutes.

[0260] After completion of the emulsification or dispersion step (a3), there is an oil-in-water emulsion in which the inner oil phase with the active substance to be encapsulated is finely dispersed or emulsified in the form of droplets in the outer aqueous phase.

[0261] In a subsequent step (a4) of the process according to the invention, the material of the capsule shell or capsule wall is subjected to a first polymerization and / or crosslinking, also under stirring, by adding at least one amino acid or at least one amino acid hydrochloride, preferably in the form of an aqueous solution, and by adding a catalyst.

[0262] At least one first amino acid is selected from the group consisting of arginine, histidine, lysine, tryptophan, ornithine, and mixtures thereof.

[0263] It is generally advantageous to use the amino acid as a hydrochloride salt. The hydrochloride salt of the amino acid is more soluble in water. In addition, the use of the amino acid as a hydrochloride salt shifts the pH of the reaction mixture to an acidic one, which is expected to be more soluble in water, in addition to improving solubility, increasing the reactivity between the at least one polyisocyanate and the first amino acid and thus increasing polymerization and / or crosslinking between the two components.

[0264] The at least one amino acid hydrochloride is selected from the group consisting of arginine hydrochloride, histidine hydrochloride, lysine hydrochloride, tryptophan hydrochloride, ornithine hydrochloride, and mixtures thereof.

[0265] The amino acids arginine, lysine and ornithine or the corresponding amino acid hydrochlorides are compounds each having two amino groups in the side chain. The amino acids histidine and tryptophan or the corresponding hydrochlorides each have one amino group and one NH functional group in the side chain. Therefore, the above amino acids or their amino acid hydrochlorides show multifunctionality in polymerization with at least one polyisocyanate. Due to the crosslinking between the at least one polyisocyanate and the functional groups of the at least one amino acid or amino acid hydrochloride, a first crosslinking unit or a first crosslinking matrix is ​​formed, which becomes a component of the capsule shell or capsule wall.

[0266] Among the above amino acids, the basic reactive amino acid arginine or its hydrochloride analog is particularly preferred as a cross-linking agent because of its water solubility, high reactivity and pH value, both as an amino acid and as a hydrochloride salt.

[0267] From an environmental point of view, the use of amino acids or amino acid hydrochlorides as cross-linking agents is particularly advantageous in terms of biodegradability and biocompatibility.

[0268] The amino acid or amino acid hydrochloride, i.e. the first crosslinking agent, is added to the emulsion as such (e.g. as a solid) or preferably in the form of an aqueous solution. The concentration of the amino acid or amino acid hydrochloride in the aqueous solution is 0.5 to 2 mol / L, preferably 1 mol / L.

[0269] The amount of the at least one amino acid or at least one amino acid hydrochloride is adjusted such that, per mole of isocyanate groups, 1 to 3 mol of amino groups, preferably 1 to 2 mol of amino groups, are added.

[0270] The first crosslinking in the method according to the present invention is carried out within a time period of about 10 to 20 minutes, preferably within a time period of 12 to 18 minutes, most preferably within a time period of about 15 minutes.

[0271] Inducing polymerization between the at least one polyisocyanate or multiple polyisocyanates and the first amino acid or amino acid hydrochloride does not require a specific action. The amino acid or amino acid hydrochloride begins to react immediately after adding the oil-in-water emulsion or dispersion to form the first cross-linked unit or the first cross-linked matrix. Since the reaction between the at least one polyisocyanate or multiple polyisocyanates and the first amino acid or amino acid hydrochloride is fast enough, no catalyst is required.

[0272] In the method according to the invention, the formation of the first crosslinking unit or the first crosslinking matrix is ​​based on the polyaddition reaction of polyisocyanate (one or more) with amino acids or amino acid hydrochlorides. The first crosslinking unit forming the capsule shell or capsule wall is based on a polyurea structure. The polyurea bond or polyurea structure is formed by the polyaddition of the amino groups (-NH2) of at least one amino acid or at least one amino acid hydrochloride with the isocyanate groups of at least one polyisocyanate:

[0273] n O=C=NR 1 -N=C=O+n H2N-R 2 -→(-O-NH-R 1 -NH-CO-NH-R 2 -) n

[0274] In the method according to the invention, first crosslinking units, in particular polyurea crosslinking units, are formed by interfacial polymerization at the interface of emulsified or suspended oil droplets containing the lipophilic active substance to be encapsulated. By forming the first crosslinking units, the emulsified or dispersed oil droplets with the active substance are surrounded on their outside by crosslinking units at the interface; this creates a capsule wall, making it more difficult for the encapsulated active substance to diffuse.

[0275] The addition of a catalyst to the emulsion or suspension accelerates the reaction between the polyisocyanate and the amino acid or amino acid hydrochloride and catalyzes a reaction that is favorable to the formation of a polyurea crosslinked matrix.

[0276] The process according to the invention is characterized in that the catalyst is not added to the external aqueous phase before the emulsification step, but is added to the emulsion or suspension only after the oil-in-water emulsion is obtained from step (a3).

[0277] Surprisingly, different orders of addition of the catalysts resulted in different compositions of the capsule shell or capsule wall, as in the following embodiments and Figure 3 as shown in .

[0278] Surprisingly, it was found that the addition of the catalyst has a great influence on the particle size distribution and stability of the microcapsules: the prior art microcapsules, in which the catalyst is added to the aqueous phase before the emulsification step, have a significantly lower stability. The microcapsules according to the invention have a significantly higher stability, even after 10 days at 50° C., and a significantly lower free aromatic oil compared to control microcapsules, which are prepared according to the prior art and in which the catalyst is added directly to the external aqueous phase already in the emulsification or suspension step, as shown in the following examples.

[0279] In this case, it does not matter whether the catalyst is added together with the first amino acid after the emulsification step or separately from the first amino acid, i.e. before or after the addition of the first amino acid. Despite the different methods of adding the catalyst, microcapsules of consistent quality, i.e. stability, can be obtained, as shown in the following examples. More advantageously, the catalyst is first dispersed or dissolved in water and then added to the emulsion or suspension.

[0280] The catalyst added in the method according to the invention is preferably diazabicyclo[2.2.2]octane (DABCO), also known as triethylenediamine (TEDA), a bicyclic tertiary amine. DABCO is commonly used as a catalyst for the preparation of polyurethane plastics. The tertiary amine with a free electron pair promotes the reaction between at least one polymerizable polyisocyanate in the internal non-aqueous phase and the amino group of the amino acid or amino acid hydrochloride in the external aqueous phase.

[0281] In addition to DABCO, catalysts based on bismuth or tin are used, for example, to catalyze the initial crosslinking, for example catalysts based on bismuth(II) salts or based on bismuth(III) salts, as described in KC Frisch and LP Rumao, Catalysis in Isocyanate Reactions, Polymer Reviews, 1970, 5: 1, pages 103 to 149, DOI: 10.1080 / 15583727008085365, the disclosure of which in this regard is incorporated in its entirety into the present description.

[0282] Particularly preferred is diazabicyclo[2.2.2]octane (DABCO) as catalyst.

[0283] According to the invention, a combination of DABCO and one of the above-mentioned catalysts is preferred. Such a mixture leads to a multiplication of the reactivity, as described in KC Frisch and LPRumao, Catalysis in Isocyanate Reactions, Polymer Reviews, 1970, 5: 1, pages 103 to 149, DOI: 10.1080 / 15583727008085365, the disclosure of which in this regard is fully incorporated into the present specification.

[0284] In the process according to the invention, DABCO and the above-mentioned catalysts preferably catalyze the polyurethane reaction between at least one polymerizable polyisocyanate having two or more isocyanate groups and a diol or polyol.

[0285] Particularly stable microcapsules can be prepared using the catalyst diazabicyclo[2.2.2]octane (DABCO).

[0286] The amount of catalyst added to the emulsion or suspension is in the range of 0.01 to 1 wt %, and preferably in the range of 0.05 to 0.2 wt %, relative to the total weight of the emulsion or suspension. In the case of slow polymerization, the amount of catalyst required can be adjusted accordingly.

[0287] The ratio of catalyst in the emulsion or suspension to the at least one polyisocyanate in the inner non-aqueous phase is preferably in the range of 1:20 to 1:50.

[0288] It has proven to be advantageous to first disperse or dissolve the catalyst in water and then add it to the emulsion or dispersion with stirring.

[0289] In the method according to the present invention, the addition of the amino acid or amino acid hydrochloride and the catalyst is preferably carried out at a stirring speed of 500 to 2000 rpm, particularly preferably at a stirring speed of 1000 to 1500 rpm, and preferably at a temperature of 20°C to 30°C, preferably at a temperature of 22°C to 25°C.

[0290] In the method according to the invention, the first polymerization and / or crosslinking is carried out for a period of about 10 to 20 minutes, preferably for a period of 12 to 18 minutes, and most preferably for a period of about 15 minutes.

[0291] Surprisingly, the addition of the catalyst after the emulsification or dispersion step leads to a significant improvement in the stability of the capsules. Compared to control microcapsules prepared without the addition of catalyst, capsules prepared in this way have significantly higher stability even after 10 days at 50°C and significantly less free aromatic oil.

[0292] Particularly stable capsules can be prepared using the catalyst diazabicyclo[2.2.2]octane (DABCO).

[0293] In the process according to the invention, the first polymerization and / or crosslinking step (a) is followed by a further, second polymerization and / or crosslinking step (b) by adding at least one hydroxyl donor to the oil-in-water emulsion to further crosslink the capsule shell or capsule wall.

[0294] The at least one hydroxyl donor is preferably a polyol having two or more hydroxyl functional groups which has good to very good water solubility at temperatures above 40°C.

[0295] The hydroxyl donor is selected from the group consisting of glycerol, propylene glycol, 1,3,5-trihydroxybenzene, starch, modified starch and cellulose derivatives such as hydroxyethylcellulose, especially quaternized hydroxyethylcellulose or carboxymethylcellulose, gum arabic (Senegal and Seyir types) and mixtures thereof. Preferred are glycerol and starch, most preferred is glycerol.

[0296] The starch used in the process according to the invention is selected from the group consisting of corn starch, potato starch, rye starch, wheat starch, barley starch, oat starch, rice starch, pea starch, tapioca starch and mixtures thereof.

[0297] The chemically modified starch is preferably acid-modified starch, alkali-modified starch, oxidized starch, acetylated starch, succinate-ated starch or octenylsuccinate-ated starch.

[0298] According to the invention, a combination of two different abovementioned hydroxyl donors can also be used for preparing the microcapsules according to the invention. Advantageously, a combination with glycerol or starch is used.

[0299] Depending on their size, the abovementioned hydroxyl donors have different reaction rates with the isocyanate groups of the at least one polyisocyanate. For example, due to its size, glycerol (eg compared to starch) reacts faster with isocyanate groups.

[0300] The combination of glycerol with starch or with modified starch, or glycerol with quaternized hydroxyethylcellulose and gum arabic of the Seychelles type, has proven to be a particularly advantageous combination. By means of such a combination, the above-mentioned properties of the two hydroxyl donors are utilized: on the one hand, the high reaction rate of glycerol, and on the other hand, the number of polymerizable functional groups of the other hydroxyl donor.

[0301] By reacting at least one polyisocyanate with the hydroxyl groups of the hydroxyl donor, further, second crosslinking units or a second crosslinking matrix for building or forming the capsule shell or capsule wall are formed, which has a structure similar to the above-mentioned polyurethane crosslinking units formed from polyisocyanate and protective colloid.

[0302] The polyaddition reaction of at least one polyisocyanate with a hydroxyl donor results in the formation of a urethane bridge (-NH-CO-C-) by adding the hydroxyl group (-OH) of the hydroxyl donor to the carbon atom of the carbon-nitrogen bond (-N=C=O) of the polyisocyanate group.

[0303] By forming such further polyurethane crosslinking units, the first polyurea crosslinking units formed in the first polymerisation and / or crosslinking step (a4) are further densified.

[0304] In order to obtain particularly effective, dense and stable crosslinking, the second polymerization and / or crosslinking step with the hydroxyl donor is carried out at a temperature of 40°C to 60°C, preferably at a temperature of 45°C to 55°C, more preferably at a temperature of 45°C to 50°C.

[0305] Furthermore, a further crosslinking step is preferably carried out by adding a hydroxyl donor at a stirring speed of 900 to 1700 rpm, preferably 1000 to 1300 rpm.

[0306] In this context, it is noteworthy that the addition of aqueous hydroxyl donors leads to particularly stable crosslinking and thus to particularly stable capsule shells or capsule walls. Preferably, the concentration of the hydroxyl donor in the aqueous solution is 10% to 70%, even more preferably, the concentration of the hydroxyl donor in the aqueous solution is 40% to 60%.

[0307] In the process according to the invention, the second polymerization and / or crosslinking step (b) is followed by a further, third polymerization and / or crosslinking step (c). In this third polymerization and / or crosslinking step, at least one basic amine or guanidinium donor is added as a third crosslinking agent to the oil-in-water emulsion obtained in the crosslinking step (b). The basic amine and guanidinium donor are selected from the group consisting of arginine, arginine hydrochloride, guanidine carbonate, guanidine hydrochloride, guanine, guanosine, creatine, creatinine and mixtures from both groups of crosslinking agents.

[0308] Arginine (NH2-C(=NH)-R) and guanidine donor Due to its structure and the number of amino groups, it has high reactivity and functionality when polymerized with at least one polyisocyanate.

[0309] The third crosslinking agent is added to the emulsion or suspension as such (eg as a solid) or preferably in the form of an aqueous solution. The concentration of the second crosslinking agent in the aqueous solution is 0.5 to 2 mol / l, preferably 1 mol / l.

[0310] In the method according to the invention, a third crosslinking matrix or third crosslinking unit is formed by adding a third crosslinking agent. These third crosslinking units are based on the polyaddition reaction of a single polymer or oligomer of polyisocyanate (one or more) with amino groups to form a capsule shell or capsule wall based on a polyurea structure. The polyurea bond or polyurea structure is formed by the polyaddition of the amino groups (-NH2) of at least one basic amine and / or guanidine donor with the isocyanate groups of at least one polyisocyanate:

[0311] n O=C=NR 1 -N=C=O+n H2N-R 2 -+→(-O-NH-R 1 -NH-CO-NH-R 2 -) n

[0312] By forming such further polyurea crosslinking units, the polyurea crosslinking units and the polyurethane crosslinking units formed in the first and second polymerization and / or crosslinking steps (a4) and (b) are further crosslinked and densified.

[0313] In the method according to the present invention, the third crosslinking is performed within a time period of about 10 to 20 minutes, preferably within a time period of 12 to 18 minutes, and most preferably within a time period of about 15 minutes.

[0314] The third cross-linking step is carried out at a temperature of 60 to 80°C, preferably 65 to 75°C.

[0315] The combination of a first crosslinking step between the polyisocyanate and the first amino acid, a second crosslinking step between the polyisocyanate and the hydroxyl donor and a third crosslinking step between the polyisocyanate and the basic amine or guanidine donor makes it possible to generate polyurea and polyurethane crosslinking units or a crosslinking matrix, which constitutes the capsule shell or capsule wall. During the process according to the invention, the first, second and third polyurea and polyurethane crosslinking units are further spatially crosslinked with each other by sequential crosslinking steps.

[0316] The greater the number of crosslinking functional groups, the greater the degree of spatial crosslinking, and the better the stability of the capsule shell or capsule wall of the resulting microcapsules. For example, the large number of hydroxyl groups in starch can form particularly strong crosslinks in space. In addition to the number of functional groups, the chain length of the individual capsule shell or capsule wall components also has a great influence on the mechanical properties, i.e. the stability, of the microcapsules: long-chain capsule shell or capsule wall components (e.g. polyisocyanates) lead to more stable capsule shells or capsule walls.

[0317] During the cross-linking step, the stirring power is reduced, preferably to a stirring speed of about 800 to 1200 rpm, in order not to disrupt the cross-linked units that are being formed and that constitute the capsule shell.

[0318] After the third polymerization and / or crosslinking step and complete crosslinking and formation of the capsule shell or capsule wall, the capsules prepared according to the process of the invention are present as crude microcapsules in the form of an aqueous dispersion or slurry / suspension.

[0319] After crosslinking, the microcapsules in the slurry still have a flexible shell which is not particularly stable and therefore easily breaks. For this purpose, the shells of the microcapsules are cured. Preferably, curing is achieved by gradually increasing the microcapsule dispersion to a temperature of at least 60° C., preferably a temperature in the range of 60° C. to 65° C., up to the boiling point of the microcapsule dispersion. Curing is generally carried out for at least 60 minutes, preferably 2 to 4 hours.

[0320] In addition, it is advantageous to add a substance for curing in the external aqueous phase. For this purpose, natural plant tannins of the tannin type are used, which, from a chemical point of view, are proanthocyanidins found in dicotyledonous perennials, shrubs and leaves, in particular in tropical and subtropical areas. The molecular weight of terpenes is generally in the range of 500 to 3000 KDa. A preferred example of a suitable tannin is Corigallin. For curing, an aqueous preparation of tannin is added to the aqueous dispersion containing the crude microcapsules. Typically, the tannin is added in an amount of about 0.1 to about 2% by weight, preferably about 0.5 to about 1.5% by weight, relative to the microcapsules.

[0321] The microcapsules prepared according to the method of the present invention exist in the form of a dispersion in water after solidification, and the dispersion is also called a microcapsule dispersion or a microcapsule slurry. Microcapsules in this form are basically ready for sale.

[0322] In order to prevent segregation or creaming of such suspensions and thus to achieve a high storage stability, a viscosity of the suspension of 12 to 1500 mPas has proven to be advantageous. In order to achieve the desired viscosity of the suspension, thickeners are preferably used.

[0323] The thickener is preferably xanthan gum, diuthan gum, carboxymethyl cellulose (CMC), microcrystalline cellulose (MCC) or guar gum.

[0324] In order to improve the shelf life, one or more preservatives may be added to the microcapsule slurry, or the microcapsule slurry may be dried.

[0325] Preference is given to using 1,2-hexanediol, 1,2-octanediol or parmetol as preservatives.

[0326] Alternatively, the microcapsules are isolated and dried for storage purposes.

[0327] In principle, processes such as freeze drying can be used for this, but spray drying, for example in a fluidized bed, is preferred. It has proven advantageous to further add a polysaccharide, preferably a dextrin, in particular a maltodextrin, to the dispersion at a temperature of about 20° C. to about 50° C., preferably about 40° C., which supports the drying process and protects the capsules during this process. In this case, the amount of polysaccharide used can be about 50 to about 150% by weight, preferably about 80 to about 120% by weight, relative to the mass of capsules in the dispersion.

[0328] The spray drying itself can be carried out continuously or batchwise in conventional spray equipment with an inlet temperature of about 170°C to about 200°C, preferably about 180°C to 185°C, and an outlet temperature of about 70°C to about 80°C, preferably about 72°C to 78°C.

[0329] An important criterion for the suitability of microcapsules is the weight ratio of core material to capsule wall material. On the one hand, in order to make the capsules as practical as possible, it is necessary to strive for the highest possible core material content. On the other hand, the capsules must have a sufficient amount of capsule wall material to ensure the stability of the capsules.

[0330] According to the invention, it has proven particularly advantageous if the microcapsules are designed as microcapsules with a weight ratio of core material to capsule wall material of 50:50 to 90:10, preferably of 70:30 to 80:20.

[0331] The microcapsules prepared according to the process of the present invention can be characterized by the d(0.5) value of their size distribution, ie 50% of the prepared capsules are larger than this value and 50% of the capsules are smaller than this value.

[0332] The microcapsules according to the present invention are prepared from an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 80:20. In addition, lysine*HCl is used as the first amino acid, glycerol is used as a hydroxyl donor, and guanidine carbonate is used as a second amino acid / guanidinium donor. DABCO is used as a catalyst, Seyir type gum arabic is used as a protective colloid, and quaternized hydroxyethyl cellulose is used as an emulsifier. TomCap is used as the phase to be encapsulated. The catalyst is added to the reaction mixture only after the emulsification step.

[0333] Microcapsules according to the prior art are prepared by using an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 80:20. Lysine*HCl is used as the first amino acid, glycerol as the hydroxyl donor, and guanidine carbonate as the second amino acid / guanidinium donor. DABCO is used as the catalyst and polyvinyl alcohol as the protective colloid. TomCap is used as the phase to be encapsulated. The catalyst is added and dissolved in the aqueous phase before emulsification.

[0334] To determine the particle size, the microcapsules according to the invention and the microcapsules of the prior art were dispersed in water within the scope of a dynamic process and the particle size was then determined by means of laser diffraction. Depending on the size of the capsule, the laser beam is refracted differently and can therefore be converted into a size. The Mie theory is used for this. The particle size measurement was performed using a Malvern Mastersizer 3000 particle size analyzer.

[0335] The microcapsules according to the present invention are characterized in that their particle size distribution has a d(0.5) value of 10 μm to 80 μm, preferably a d(0.5) value of 20 μm to 65 μm. The corresponding particle size distributions of the microcapsules according to the present invention and the microcapsules of the prior art are shown in Figure 2 middle.

[0336] A direct comparison of the microcapsules shows that using the process according to the invention microcapsules with a significantly better particle size distribution can be produced compared to microcapsules produced according to the prior art.

[0337] Figure 3 Infrared images of microcapsules according to the present invention and microcapsules of the prior art are shown.

[0338] The microcapsules according to the present invention are prepared by combining hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 75:25. In addition, lysine*HCl is used as the first amino acid, glycerol is used as a hydroxyl donor, and guanidine carbonate is used as a basic amine / guanidinium donor for crosslinking. DABCO is used as a catalyst, Seyir-type gum arabic is used as a protective colloid, and quaternized hydroxyethylcellulose is used as an emulsifier. The catalyst is added only after the emulsification step.

[0339] The prior art microcapsules are prepared by combining hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 80:20. In addition, lysine*HCl is used as the first amino acid, and guanidine carbonate is used as a basic amine / guanidine donor for crosslinking. DABCO is used as a catalyst and polyvinyl alcohol as a protective colloid. The catalyst is added and dissolved in the aqueous phase before emulsification.

[0340] The following figure shows clear differences between the bands, especially in the fingerprint region. -1 At 1500 cm-1, more intense bands can be identified compared to the state of the art, which indicate polyurethanes and polyesters (e.g. caused by gum arabic). -1 There is a new band at 1750 cm indicating a C=C bond, which can be attributed to aromatic isocyanate. -1 At , vibrations indicate a significant increase in the proportion of carbonyl carbons. Comparison of infrared spectra shows that the microcapsules according to the invention differ from the microcapsules of the prior art in composition. Comparison of infrared spectra further shows that both the microcapsules according to the invention and the microcapsules of the prior art are composed of a polyurea / polyurethane network or polymer.

[0341] Advantageously, the method for preparing polyurea / polyurethane microcapsules according to the invention is characterized in that the execution of the method steps, in particular the execution of the crosslinking steps, is pH-independent. Therefore, the method according to the invention is simpler and less time-consuming to implement than encapsulation methods according to the prior art.

[0342] Although simpler and less time-consuming to implement, the process according to the invention allows the preparation of microcapsules with better properties, i.e. without loss or compromise in the functionality of the microcapsules, such as olfactory properties and positive secondary properties, such as high stability, i.e. the ability to retain the active ingredient.

[0343] In addition, the pH-independent implementation of the crosslinking step also advantageously allows lipophilic active substances with aldehyde, carboxylic acid or ester functional groups to be encapsulated. The polyisocyanate-based capsule shells of the prior art can usually only encapsulate selected active substances. However, encapsulation with polyisocyanates according to the prior art is not suitable for the encapsulation of fragrances or aromatic oils with aldehyde, carboxylic acid or ester functions. During the encapsulation process at alkaline pH, carboxylic acids are deprotonated, oxidized aldehydes (carboxylic acids) are similarly deprotonated, and esters are saponified, resulting in a loss of lipophilic active substances, and on the other hand, the obtained emulsion becomes unstable. Therefore, for active substances, the use of such microencapsulation has limitations, for example, it is only applicable to a small range of fragrances or aromatic oils, and such a microencapsulation method is excluded for fragrances or aromatic oils with aldehyde, carboxylic acid or ester functions. However, fragrances with aldehyde, carboxylic acid or ester functions belong to the most important representatives of fragrances or aromatic oils. Therefore, the pH-independent crosslinking step in the method according to the invention enables the effective encapsulation of such lipophilic fragrances or fragrance oils.

[0344] Using the method according to the invention, alternately defined crosslinking units based on polyurea and polyurethane can be deposited around a core containing a lipophilic active substance by interfacial polymerization, thereby producing a stable capsule wall or capsule shell structure. The main component of the capsule shell or capsule wall is essentially a polyurea or polyurethane crosslinking matrix or crosslinking unit. In this process, the crosslinking units are crosslinked to each other to form a three-dimensional network structure, thereby contributing to the stability of the capsule shell or capsule wall. In addition, protective colloids (e.g. starch) can be present in the capsule shell or capsule wall via polyurethane bonds.

[0345] In another aspect, the present invention relates to polyurea / polyurethane microcapsules prepared by the process according to the present invention.

[0346] The polyurea / polyurethane microcapsules are characterized in that they consist of or contain:

[0347] a core comprising at least one hydrophobic active substance; and

[0348] A capsule shell comprising a reaction product produced from:

[0349] - crosslinking of polyisocyanates having two or more isocyanate groups with at least one amino acid or amino acid hydrochloride and a catalyst in the presence of a protective colloid,

[0350] - further crosslinking / polymerization with at least one hydroxyl donor, and

[0351] - Further crosslinking / polymerization with at least one basic amine and / or guanidinium donor.

[0352] The sequential crosslinking of the polyisocyanate units with amino or hydroxyl functions in three crosslinking steps involves not only linear crosslinking but also three-dimensional, i.e. spatial crosslinking, which results in a stable capsule wall formed from an alternating, defined, dense and therefore stable crosslinking matrix or crosslinking units based on polyurethane and polyurea.

[0353] In a preferred embodiment, the capsule shell of the polyurea / polyurethane microcapsules according to the invention comprises:

[0354] (i) a first crosslinking matrix or crosslinking unit formed by polymerization and / or crosslinking of at least one polyisocyanate having two or more polyisocyanate groups with at least one protective colloid and at least one first amino acid or amino acid hydrochloride;

[0355] (ii) a second crosslinking matrix or crosslinking units formed by polymerization and / or crosslinking of at least one polyisocyanate having two or more polyisocyanate groups and at least one hydroxyl donor; and

[0356] (iii) a third crosslinking matrix or crosslinking unit formed by polymerization and / or crosslinking of at least one polyisocyanate having two or more polyisocyanate groups with at least one basic amine and / or guanidine donor.

[0357] The first crosslinking matrix or crosslinking unit of the capsule shell of the microcapsule according to the present invention is a polyurea-based network. The second crosslinking matrix or crosslinking unit is a polyurethane-based network, and the third crosslinking matrix or crosslinking unit is another polyurea-based network. Preferably, the first crosslinking matrix and / or the second crosslinking matrix and / or the third crosslinking matrix are further crosslinked to each other via the functional groups of their components.

[0358] The composition of the polyurea and polyurethane crosslinking units depends on the polyisocyanates and crosslinking agents used, i.e. protective colloids, amino acids, hydroxyl donors and basic amine or guanidine donors. The crosslinking units produced in the crosslinking step are further crosslinked during the process according to the invention via free functional groups, thus forming a three-dimensionally crosslinked or spatially crosslinked capsule shell or capsule wall.

[0359] In addition to the above-mentioned formation of polyurethane and polyurea, due to the reactivity of polyisocyanates, by-products such as urea, allophanate, biuret, uretdione, carbodiimide and uretonimine are generated in the above-mentioned crosslinking step, as described in MF Sonnenschein, Introduction to Polyurethane Chemistry, Polyurethanes: Science, Technology, Markets, and Trends, 1st edition, 2015, John Wiley & Sons, pages 105 to 126, the disclosure of which in this regard is fully incorporated into this specification. These by-products are components of the capsule shell or capsule wall.

[0360] Surprisingly, the polyurea / polyurethane fragrance capsules prepared according to the process of the present invention have greater stability and reduced inadvertent leakage of fragrance oil, which can be attributed, among other things, to more efficient encapsulation of the fragrance, as shown in the examples below.

[0361] Surprisingly, it was found that the stability of the microcapsules prepared according to the method of the present invention is improved by at least 1.1 times, preferably 1.3 times, even more preferably 1.5 times, compared with the prior art polyurea / polyurethane microcapsules, as shown in the following embodiments.

[0362] The microcapsules according to the invention have a content of free hydrophobic active substances of 0.5% by weight or less, preferably of 0.3% by weight or less, even more preferably of 0.2% by weight.

[0363] Furthermore, the polyurea / polyurethane microcapsules according to the invention also have a significant improvement in the organoleptic properties (fragrance release) compared to the capsules of the prior art, which is at least 1.1 to at least 1.5 times better, which can be attributed to the stable active substance encapsulation and the associated low active substance loss. Figure 4 As shown in , the microcapsules according to the invention show a significantly higher sensory intensity when the capsules are opened to release the fragrance either by mechanical friction or by pressure.

[0364] Furthermore, the microcapsules of the present invention are universal capsules which, according to the present state, can be used to encapsulate a wide range of aromas or flavors, even those having aldehyde, carboxylic acid or ester functions, and therefore are not limited to individual active substances.

[0365] Due to their advantageous properties, in particular their stability and the targeted release of active substances, the microcapsules according to the invention are suitable for a wide range of applications, in particular for household products, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance lotions and fragrance enhancers, cosmetics, personal care products, agricultural products, pharmaceutical products, paper printing coatings, etc.

[0366] Therefore, the present invention relates in another aspect to the use of the polyurea / polyurethane microcapsules according to the invention or the dispersions of the polyurea / polyurethane microcapsules according to the invention for the manufacture of household goods, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance lotions and fragrance enhancers, cosmetics, personal care products, agricultural products, pharmaceutical products, paper printing coatings, etc.

[0367] Finally, the present invention relates to household items, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance lotions or fragrance enhancers, cosmetics, personal care products, agricultural products, pharmaceutical products, paper printing coatings, etc., comprising the polyurea / polyurethane microcapsules according to the invention or suspensions of the polyurea / polyurethane microcapsules according to the invention.

[0368] Example

[0369] The polyurea / polyurethane microcapsules according to the invention and their advantageous properties will be described in more detail by means of the following examples.

[0370] Example 1 - Capsule Stability

[0371] The following stability data refer to tests performed at 50°C using commercially available formulations such as fragrance boosters or fabric softeners.

[0372] The following capsules are usually selected as capsules of the prior art, whose capsule walls are also formed by a polyurea / polyurethane network. The capsules of the prior art are prepared by using an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 80:20. Lysine*HCl is used as the first amino acid, glycerol is used as the hydroxyl donor, and guanidine carbonate is used as the second amino acid / guanidine donor. DABCO is used as the catalyst and polyvinyl alcohol is used as the protective colloid. TomCap is used as the phase to be encapsulated. Before emulsification, the catalyst is added and dissolved in the aqueous phase.

[0373] The microcapsules according to the present invention are prepared by using an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 80:20. In addition, lysine*HCl is used as the first amino acid, glycerol is used as the hydroxyl donor, and guanidine carbonate is used as the second amino acid / guanidinium donor. DABCO is used as a catalyst, Seyir type gum arabic is used as a protective colloid, and quaternized hydroxyethylcellulose is used as an emulsifier. TomCap is used as the phase to be encapsulated. The catalyst is added to the reaction mixture only after the emulsification step.

[0374] Free oil was determined by placing the slurry in isopropanol for 30 seconds and then measuring the remaining oil in the microcapsules by solid phase microextraction (SPME) and GC / MS.

[0375] Table 1:

[0376] sample 3 days at 50℃ / % 10 days at 50℃ / % d(0.5) / μm d(0.9) / μm The present invention 70 61 25.5 45.0 Prior art 46 34 30.9 94.7

[0377] Compared with the microcapsules of the prior art, the microcapsules according to the present invention are significantly more stable and have significantly better particle size distribution. Under good particle size distribution, the capsule stability of the microcapsules according to the present invention is still high. The particle size distribution of the microcapsules according to the present invention and the particle size distribution of the microcapsules of the prior art are shown in Figure 2 middle.

[0378] Application Example 2-Process Simplification

[0379] Example 1:

[0380] The microcapsules according to the invention were prepared using an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 75:25. In addition, lysine*HCl was used as the first amino acid, glycerol as the hydroxyl donor, and guanidine carbonate as the second amino acid / guanidinium donor. DABCO was used as a catalyst, Seyir type gum arabic as a protective colloid, and quaternized hydroxyethylcellulose as an emulsifier. TomCap was used as the phase to be encapsulated. The catalyst was added separately after the emulsification step.

[0381] Example 2:

[0382] The microcapsules according to the invention were prepared using an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 75:25. In addition, lysine*HCl was used as the first amino acid, glycerol as the hydroxyl donor, and guanidine carbonate as the second amino acid / guanidinium donor. Seyir-type gum arabic was used as the protective colloid and quaternized hydroxyethylcellulose as the emulsifier. TomCap was used as the phase to be encapsulated. The catalyst was added simultaneously, i.e. together, with the first amino acid lysine*HCl after the emulsification step.

[0383] The microcapsules of Examples 1 and 2 according to the present invention were compared with the prior art microcapsules described above.

[0384] Table 2:

[0385] sample 3 days at 50℃ / % 10 days at 50℃ / % d(0.5) / μm d(0.9) / μm Example 1: 70 61 25.5 45.0 Example 2: 69 56 27.8 61.2 Prior art 46 34 30.9 94.7

[0386] As shown in the values ​​in Table 2, the addition of the catalyst has a significant effect on the particle size distribution and stability of the microcapsules: the microcapsules of the prior art, in which the catalyst is added to the aqueous phase before the emulsification step, have significantly lower stability. The microcapsules according to the present invention, in which the catalyst is added after the emulsification step, have significantly higher stability. Therefore, it does not matter whether the catalyst is added together with the first amino acid after the emulsification step or added separately, i.e., after the addition of the first amino acid. Despite the different addition methods, microcapsules with consistent quality, i.e., uniform stability, are obtained.

[0387] Example 3 - Capsule stability as a function of polyisocyanate composition (comparison of a single polyisocyanate and a combination of two different polyisocyanates)

[0388] The microcapsules according to the present invention were prepared using different single polyisocyanates or a combination of two different polyisocyanates, guanidine carbonate, polyvinyl alcohol as protective colloid and TomCap as fragrance oil.

[0389] Table 3:

[0390]

[0391] The stability of the microcapsules obtained by using a combination of two different isocyanates even exceeds that of a single isocyanate system. Therefore, it is preferred to use a mixture consisting of two different isocyanates.

[0392] Example 4 - Capsule stability associated with hydroxyl donors

[0393] The microcapsules according to the present invention are prepared by using an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 80:20. In addition, lysine*HCl is used as the first amino acid, glycerol or 1,3,5-trihydroxybenzene is used as a hydroxyl donor, and guanidine carbonate is used as a second amino acid / guanidinium donor. DABCO is used as a catalyst and octenyl succinate starch is used as a protective colloid. TomCap is used as the phase to be encapsulated. The catalyst is added to the reaction mixture only after the emulsification step.

[0394] Table 4:

[0395] Hydroxyl donor Free oil / % 3 days at 50℃ / % 10 days at 50℃ / % glycerin 0.02 88 85 1,3,5-Trihydroxybenzene 0.19 50 47

[0396] The use of glycerol as the hydroxyl donor resulted in more stable microcapsules than the use of 1,3,5-trihydroxybenzene. Glycerol is more reactive than aromatic hydroxyl donors due to its size.

[0397] Example 5 - Sensory Test

[0398] For the sensory evaluation, the microcapsules according to the invention were compared with microcapsules of the prior art as described above, ie microcapsules based on a polyurea / polyurethane structure, in which the catalyst was added to the aqueous phase before the emulsification step.

[0399] The microcapsules according to the present invention are prepared from hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 75:25. In addition, lysine*HCl is used as the first amino acid, glycerol is used as a hydroxyl donor, and guanidine carbonate is used as a second amino acid / guanidine donor. DABCO is used as a catalyst, Seyir type gum arabic is used as a protective colloid, and quaternized hydroxyethyl cellulose is used as an emulsifier. TomCap is used as the phase to be encapsulated.

[0400] The sensory evaluation was conducted in the following manner: The above microcapsules were respectively added to a fabric softener having an oil concentration of 0.2 wt%, and then washed. A mixed fiber cloth made of cotton and polyester was smelled.

[0401] Twelve testers rated the intensity of the odor of the mixed fiber cloth after washing on a scale from 1 (no fragrance) to 9 (very strong fragrance). The fragrance rating was carried out in this case in three steps. The first step describes the odor of the untreated cloth. The second step describes the odor of the cloth after it has been gently kneaded; instead, the cloth is subjected to slight mechanical pressure by moving it back and forth between the hands several times, causing the capsules to break. The third step describes the odor of the cloth after it has been rubbed vigorously, so that the capsules break.

[0402] The results of the sensory test are shown in Table 4. The microcapsules according to the invention have significantly better performance (fragrance release). This can be attributed to the targeted system changes: by adding the catalyst only after the emulsification step, significantly more stable microcapsules with a stronger smell can be obtained.

Claims

1. A method for preparing polyurea / polyurethane microcapsules, the method comprising the following steps in order: (a) performing a first polymerization and / or cross-linking step by: (a1) providing an inner non-aqueous phase comprising at least one polyisocyanate having two or more isocyanate groups and at least one active substance to be encapsulated; (a2) providing an external aqueous phase comprising at least one protective colloid and optionally at least one emulsifier; (a3) mixing the inner non-aqueous phase and the outer aqueous phase to obtain an oil-in-water emulsion or dispersion; (a4) adding at least one amino acid or amino acid hydrochloride and a catalyst; (b) carrying out a second polymerization and / or crosslinking step by adding at least one hydroxyl donor; (c) performing a third polymerization and / or crosslinking step by adding at least one basic amine or guanidine donor to obtain a microcapsule dispersion; (d) curing the microcapsule dispersion at a temperature of at least 60° C. for at least 60 minutes; and (e) optionally separating the microcapsules from the reaction mixture and optionally drying the microcapsules or adjusting the viscosity of the microcapsule slurry by adding a thickener.

2. The method according to claim 1, wherein the at least one polyisocyanate having two or more isocyanate groups is selected from the group consisting of aliphatic, aromatic or heterocyclic polyisocyanates, their substitution products, and mixtures of the above-mentioned aliphatic, aromatic or heterocyclic polyisocyanates, their substitution products.

3. The method according to claim 2, wherein the at least one polyisocyanate having two or more isocyanate groups is selected from alicyclic polyisocyanates.

4. The method according to claim 2, wherein the at least one polyisocyanate having two or more isocyanate groups is selected from hydrogenated aromatic polyisocyanates.

5. The method of claim 1, wherein the at least one polyisocyanate comprises two aliphatic polyisocyanates or one aliphatic and one aromatic polyisocyanate.

6. The method according to claim 1, wherein the at least one polyisocyanate comprises at least two polyisocyanates having different chain lengths and / or comprises at least two polyisocyanates in an alternating monomeric, oligomeric or polymeric structure.

7. The method according to any one of the preceding claims 1 to 6, wherein the at least one active substance to be encapsulated is a lipophilic active substance selected from the group consisting of fragrances, flavoring agents, cooling agents, TRPV1 and TRPV3 modulators, substances that cause a pungent taste or a hot or warm sensation on the skin or mucous membranes, or substances that cause a tingling sensation in the mouth or throat, or active substances with a stimulating or pungency or astringent effect, food additives, cosmetic active substances, pharmaceutical active substances, dyes, dye precursors, agrochemicals, optical brighteners, solvents, silicone oils, lubricants, and mixtures of two or more of the above active substances.

8. The method according to claim 7, wherein the lipophilic active substance is selected from pesticides.

9. The method according to claim 7, wherein the lipophilic active substance is selected from biocides.

10. The method according to claim 7, wherein the lipophilic active substance is selected from insecticides.

11. The method according to claim 7, wherein the lipophilic active substance is selected from the class of insect repellents.

12. The method according to claim 7, wherein the lipophilic active substance is selected from fluorescent dyes.

13. The method according to claim 7, wherein the lipophilic active substance is selected from paper printing coatings.

14. The method according to claim 7, wherein the lipophilic active substance is selected from waxes.

15. The method according to any one of the preceding claims 1 to 6, wherein the at least one active substance to be encapsulated is a lipophilic active substance selected from the group consisting of fragrances or flavorings having an aldehyde, carboxylic acid or ester function.

16. The method according to any one of the preceding claims 1 to 6, wherein the at least one protective colloid is selected from the group consisting of: - polyols, - Polyvinyl pyrrolidone, maleic acid vinyl copolymer, sodium lignin sulfonate, maleic anhydride / styrene copolymer, ethylene / maleic anhydride copolymer, copolymer of ethylene oxide, propylene oxide and polyethoxylated sorbitan ester, sodium lauryl sulfate, -Animal and plant polymers, and mixtures of the above polyols, polyvinyl pyrrolidone, maleic acid vinyl copolymers, sodium lignin sulfonate, maleic anhydride / styrene copolymers, ethylene / maleic anhydride copolymers, copolymers of ethylene oxide, propylene oxide and polyethoxylated sorbitan esters, sodium lauryl sulfate, and animal and plant polymers.

17. The method according to any one of claims 1 to 6, wherein the at least one protective colloid is selected from diols; triols; polyvinyl alcohol and its derivatives; polyphenols; polysaccharides; glucose; and cellulose derivatives.

18. The method according to claim 17, wherein the diol is selected from ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol, 1,2-dodecanediol.

19. The method according to claim 17, wherein the triol is selected from glycerol and its ethoxylation and propoxylation products, trimethylolpropane and its ethoxylation and propoxylation products.

20. The method of claim 17, wherein the polyvinyl alcohol derivative is selected from ammonium or sulfonate functionalized polyvinyl alcohol.

21. The method of claim 17, wherein the polyphenol comprises 1,3,5-trihydroxybenzene.

22. The method of claim 17, wherein the polysaccharide is selected from starch.

23. The method of claim 17, wherein the polysaccharide is selected from chemically, mechanically and / or enzymatically modified starches.

24. The method of claim 17, wherein the cellulose derivative is selected from the group consisting of hydroxyethyl cellulose and carboxymethyl cellulose.

25. The method of claim 24, wherein the hydroxyethyl cellulose is quaternized hydroxyethyl cellulose.

26. The method of claim 16, wherein the animal and plant polymers are selected from the group consisting of gum arabic, protein, gelatin, mastic, shellac, lignin, chitosan and saponin.

27. The method according to any one of the preceding claims 1 to 6, wherein the protective colloid is used in combination with starch.

28. The method according to any one of the preceding claims 1 to 6, wherein the at least one amino acid is selected from the group consisting of arginine, histidine, lysine, tryptophan, ornithine, arginine hydrochloride, histidine hydrochloride, lysine hydrochloride, tryptophan hydrochloride, ornithine hydrochloride, and mixtures thereof.

29. The process according to any one of the preceding claims 1 to 6, wherein the catalyst is selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane, a bismuth catalyst, a tin catalyst, and mixtures thereof.

30. The method according to any one of the preceding claims 1 to 6, wherein the hydroxyl donor is a polyol having two or more hydroxyl functional groups.

31. The method according to any one of claims 1 to 6, wherein the hydroxyl donor is glycerol, propylene glycol, 1,3,5-trihydroxybenzene, starch, modified starch, cellulose derivatives, gum arabic or mixtures thereof.

32. The method of claim 31, wherein the cellulose derivative is selected from hydroxyethyl cellulose and carboxymethyl cellulose.

33. The method of claim 32, wherein the hydroxyethyl cellulose is quaternized hydroxyethyl cellulose.

34. The method according to any one of the preceding claims 1 to 6, wherein the at least one basic amine or the at least one guanidinium donor is selected from the group consisting of arginine, arginine hydrochloride, guanidine carbonate, guanidine hydrochloride, guanine, guanosine, creatine, creatinine and mixtures thereof.

35. The process according to any one of the preceding claims 1 to 6, wherein the third polymerization and / or cross-linking step is carried out at a temperature of 60 to 80°C.

36. A polyurea / polyurethane microcapsule obtainable by a process according to any one of the preceding claims 1 to 35.

37. A polyurea / polyurethane microcapsule obtainable by a process according to any one of the preceding claims 1 to 35, said microcapsule comprising: a core comprising at least one hydrophobic active substance; and A capsule shell comprising a reaction product produced from: - crosslinking of polyisocyanates having two or more isocyanate groups with at least one amino acid or amino acid hydrochloride and a catalyst in the presence of a protective colloid, - further crosslinking / polymerization with at least one hydroxyl donor, and - Further crosslinking / polymerization with at least one basic amine and / or guanidinium donor.

38. The polyurea / polyurethane microcapsule of claim 37, wherein the capsule shell comprises: (i) a first crosslinking matrix or crosslinking unit formed by polymerization and / or crosslinking of at least one polyisocyanate having two or more polyisocyanate groups with at least one protective colloid and at least one first amino acid or amino acid hydrochloride; (ii) a second crosslinking matrix or crosslinking unit formed by polymerization and / or crosslinking of at least one polyisocyanate having two or more polyisocyanate groups and at least one hydroxyl donor; (iii) a third crosslinking matrix or crosslinking unit formed by polymerization and / or crosslinking of at least one polyisocyanate having two or more polyisocyanate groups with at least one basic amine and / or guanidine donor.

39. Use of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 or the dispersion of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 for the manufacture of household goods, textile care products, detergents, fabric softeners, cleaning agents, fragrance enhancers, cosmetics, agricultural products, pharmaceutical products or paper printing coatings.

40. Use of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 or the dispersion of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 for the manufacture of a fragrance enhancer.

41. Use of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 or the dispersion of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 for the manufacture of personal care products.

42. Household products, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, cosmetics, fragrance compositions, agricultural products, pharmaceutical products or paper printing coatings comprising the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 or the dispersion of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38.

43. A fragrance enhancer comprising the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 or a dispersion of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38.

44. A personal care product comprising the polyurea / polyurethane microcapsules according to any one of claims 36 to 38 or a dispersion of the polyurea / polyurethane microcapsules according to any one of claims 36 to 38.

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