Biodegradable polyurea / polyurethane microcapsules

Abstract

The present invention relates to a method for preparing biodegradable polyurea / polyurethane microcapsules, preferably perfumed polyurea / polyurethane microcapsules, which have a balance of biodegradability, stability and performance compared to the microcapsules of the prior art. In addition, the present invention relates to biodegradable polyurea / polyurethane microcapsules, which microcapsules include at least one lipophilic active substance 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 containing microcapsules according to the present 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, agricultural products or pharmaceutical products. Finally, the present invention relates to consumer products containing such microcapsules or microcapsule dispersions.

Description

Technical Field

[0001] The present invention relates to a method for preparing biodegradable polyurea / polyurethane microcapsules, preferably polyurea / polyurethane microcapsules containing fragrances or flavorings, the microcapsules comprising at least one lipophilic active substance. Compared with the microcapsules of the prior art, the microcapsules have a balance in terms of biodegradability, stability and performance. In addition, the present invention relates to biodegradable polyurea / polyurethane microcapsules, the microcapsules comprising at least one lipophilic active substance obtainable 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 comprising microcapsules according to the present 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, agricultural products, pharmaceutical products or paper printing coatings. Finally, the present invention relates to consumer products comprising such microcapsules or microcapsule dispersions. Background Art

[0002] Microcapsules are particles consisting of a core and a wall material that wraps the core, wherein the core can be a solid, liquid or gaseous substance, which is wrapped by a polymeric impermeable, 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 coating are also used for the wall. 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 it can also be 1 to 99% by weight.

[0003] Furthermore, the purpose of encapsulation is to protect the encapsulated effective substances or active substances, to release them in a targeted manner at a specific time, to convert liquids into a controlled powder form, to 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. 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 disruption of the capsules by crushing or shearing; disruption of the capsules by melting the wall material, disruption of the capsules by dissolving 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 natural, semi-synthetic or synthetic. 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. In addition, semi-synthetic shell materials are 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, the microcapsules produce different properties in terms of diameter, size distribution and physical and / or chemical properties.

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

[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, polyurea microcapsules are prepared in the presence of polyvinylpyrrolidone (PVP) as a protective colloid. WO 2012 / 107323 discloses a polyurea microcapsule having a polyurea shell, which comprises 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). EP 0 537467B describes microcapsules prepared from polyisocyanates containing polyoxyethylene groups in the presence of a stabilizer (such as polyvinyl alcohol). According to WO 2007 / 096592, microencapsulation can be carried out in an oil phase which is emulsified in a continuous aqueous phase which is usually stabilized by a surfactant system such as polyvinyl alcohol or its carboxylated and sulfonated derivatives.

[0009] The above exemplary delivery 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, a disadvantage of the above-mentioned prior art microcapsules is that the polymer capsule wall or capsule shell material requires a large amount of polymer to ensure sufficient stability and not suffer too great loss of active substance. In addition, microencapsulation introduces plastics into the environment where they can cause problems as "microplastics".

[0011] As the impact of plastic particles on the environment has been increasingly criticized by the public, and due to the increasing pressure from society on environmental issues, the demand for bio-based and biodegradable solutions is growing, and new materials need to be developed for microencapsulation to reduce microplastics in the environment. In this case, the focus is on bio-based and biodegradable materials.

[0012] There is therefore a need to provide polyurea / polyurethane microcapsules which have outstanding stability and outstanding release properties for the respective application on the one hand and which are predominantly or almost completely biodegradable on the other hand.

[0013] However, in the case of microcapsules, the task of reducing the amount of microplastics in the environment using biodegradable materials is not an easy task to solve, since the desired functionality of microcapsules, such as olfactory properties and positive secondary properties, such as high stability and toxicological stability, conflict with the requirement for rapid biodegradation in many applications.

[0014] It is particularly difficult to prepare microcapsules that have both good stability and good active substance release. The retention capacity of the active substance and therefore the ability of the capsule to avoid loss of volatile components depends inter alia on the stability of the capsule in the product matrix. However, capsules that have particularly good stability do not automatically exhibit good biodegradability.

[0015] As the degree of cross-linking increases, the stability of the microcapsules increases, but at the same time, the biodegradability of the capsule shell decreases. For very stable microcapsules, the performance (e.g. sensory performance) is lower because the number of microcapsules that rupture and release the active substance due to pressure, friction, etc. is reduced. If the microcapsule is very unstable, it will be destroyed during storage and will not show any performance.

[0016] Against this background, the overall object of the present invention is to provide a process for producing microcapsules which can, on the one hand, provide microcapsules with a low polymer content which simultaneously have a high stability and an excellent release profile of the encapsulated active substance in combination with good biodegradability.

[0017] Surprisingly, it has been found that this task can be solved by preparing polyurea / polyurethane microcapsules using amino acids and a release agent, which is incorporated into the microcapsule shell. The stability and organoleptic properties of the microcapsules can be further improved or optimized by targeted adjustment of the pH value during emulsification and crosslinking. By selectively using another, i.e. second, catalyst, even microcapsules with better stability and properties can be obtained. Summary of the invention

[0018] The present problem is solved by the subject matter of the independent claims. Preferred embodiments emerge from the text of the dependent claims and from the subsequent description.

[0019] Therefore, a first subject of the present invention relates to a method for preparing biodegradable polyurea / polyurethane microcapsules, which method comprises the following steps in sequence:

[0020] (a) performing a first polymerization and / or cross-linking step, comprising:

[0021] (a1) providing an inner non-aqueous phase comprising at least one polyisocyanate having two or more isocyanate groups and at least one lipophilic active substance to be encapsulated;

[0022] (a2) providing an external aqueous phase comprising at least one protective colloid and optionally an emulsifier, and adjusting the pH of the aqueous phase to a value of 1 to 5;

[0023] (a3) mixing the inner non-aqueous phase and the outer aqueous phase to obtain an oil-in-water emulsion or dispersion;

[0024] (a4) adding at least one first amino acid or amino acid hydrochloride and a first catalyst, and adjusting the pH of the emulsion or dispersion to 4 to 8;

[0025] (b) performing a second polymerization and / or crosslinking step by adding at least one hydroxyl donor;

[0026] (c) obtaining a microcapsule dispersion by adding at least one second amino acid and adjusting the pH of the emulsion or dispersion to between 4 and 8, in particular at a temperature of at least 60° C., and performing a third polymerization and / or crosslinking step;

[0027] (d) optionally adding additional catalyst and adjusting the pH of the microcapsule dispersion to between 4 and 7;

[0028] (e) curing the microcapsule dispersion obtained from step (c) or (d) at a temperature of at least 60° C. for at least 60 minutes;

[0029] (f) adding at least one release agent and incorporating the release agent into the microcapsule shell;

[0030] (g) post-curing the microcapsules obtained in step (f);

[0031] And optionally:

[0032] (h) separating the microcapsules from the microcapsule dispersion, and if necessary, drying the microcapsules or adjusting the viscosity of the microcapsule slurry by adding a thickener.

[0033] Furthermore, the subject of the invention described herein is a biodegradable polyurea / polyurethane microcapsule comprising at least one lipophilic active substance prepared by the process according to the invention.

[0034] Another aspect of the present invention is a biodegradable polyurea / polyurethane microcapsule comprising:

[0035] (i) a core comprising at least one hydrophobic active substance; and

[0036] (ii) a capsule shell comprising

[0037] - the reaction product of the polymerization and / or crosslinking of at least one polyisocyanate having two or more isocyanate groups with at least one first amino acid or amino acid hydrochloride, further polymerization and / or crosslinking with at least one hydroxyl donor, and further polymerization and / or crosslinking with at least one second amino acid in the presence of at least one protective colloid; and

[0038] - At least one release agent.

[0039] Finally, in another aspect, the present invention relates to the use of a biodegradable polyurea / polyurethane microcapsule or a dispersion composed of the polyurea / polyurethane microcapsules of the present invention for the manufacture of household products, 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, as well as consumer products prepared therefrom.

[0040] Surprisingly, it has been found within the scope of the present invention that the combination of the steps of targeted polymerization and / or crosslinking of a polyisocyanate having at least two or more isocyanate groups with a first amino acid or an amino acid hydrochloride, subsequent polymerization and / or crosslinking with a hydroxyl donor and further polymerization and / or crosslinking with a second amino acid, addition of a release agent and incorporation of the release agent into the microcapsule shell, and targeted pH adjustment of the emulsion or dispersion at the beginning of emulsification and at the beginning of each crosslinking reaction during the preparation of the microcapsules leads to stable microcapsules, which ensure effective encapsulation of lipophilic active substances and subsequent targeted release of these active substances, while the microcapsules, due to their biobased and biodegradable components, such as amino acids and release agents, have good biodegradability.

[0041] By using amino acids and release agents, it is also possible to reduce the polyisocyanate polymer content in the capsule wall or capsule shell material, i.e. replace it with a bio-based capsule wall component without affecting the stability of the microcapsule wall. In addition, the release agent is incorporated into the microcapsule shell to promote the biodegradability of the capsule wall or shell material.

[0042] 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 without limiting the present invention.

[0043] As used herein, the terms "at least one" or "at least one" or "one or more" mean 1 or more, for example 2, 3, 4, 5, 6, 7, 8, 9 or more.

[0044] The term "and / or" indicates that there is a connection or provides alternatives.

[0045] Numerical examples given in the format "from x to y" are inclusive of the values ​​given. When multiple preferred numerical ranges are given in this format, all ranges generated by combining the different endpoints are also included. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is an optical microscope image of a microcapsule according to the present invention. The microcapsule was prepared from 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 histidine as the second amino acid. DABCO was used as a catalyst, modified starch as a protective colloid; and beeswax was used as a release agent. Optical microscope imaging was performed using an Olympus BX51. The bars shown correspond to 50 μm.

[0047] Figure 2 A schematic diagram of the particle size distribution (d(0.5) value) of the microcapsules according to the present invention and the prior art microcapsules based on polyurea / polyurethane structure and without release agent is shown. The particle size distribution is determined using a Malvern Mastersizer 3000. The corresponding calculation is based on the Mie theory.

[0048] Figure 3 Schematic diagram of infrared spectrum analysis results of microcapsules according to the present invention and prior art microcapsules based on polyurea / polyurethane structure without release agent. The analysis was performed by means of ATR (attenuated total reflection) infrared spectroscopy.

[0049] Figure 4 Graph showing the biodegradability of microcapsules according to the invention compared to sodium benzoate and a toxicity control (a mixture of microcapsules according to the invention and sodium benzoate) according to OECD 301F.

[0050] Figure 5 A schematic diagram showing the results of sensory evaluation of the microcapsules according to the present invention and the prior art, ie, microcapsules based on a polyurea / polyurethane structure without a release agent.

[0051] Figure 6 is a schematic diagram showing the approximate correlation between microcapsule stability, performance, and biodegradability and the degree of cross-linking.

[0052] In the accompanying drawings, a point is used as a decimal separator. DETAILED DESCRIPTION

[0053] In a first aspect, the present invention relates to a method for preparing biodegradable polyurea / polyurethane microcapsules, preferably a method for preparing fragrance or flavor capsules, the method comprising the following steps in order:

[0054] (a) performing a first polymerization and / or cross-linking step, comprising:

[0055] (a1) providing an inner non-aqueous phase comprising at least one polyisocyanate having two or more isocyanate groups and at least one lipophilic active substance to be encapsulated;

[0056] (a2) providing an external aqueous phase comprising at least one protective colloid and optionally an emulsifier, and adjusting the pH of the aqueous phase to a value of 1 to 5;

[0057] (a3) mixing the inner non-aqueous phase and the outer aqueous phase to obtain an oil-in-water emulsion or dispersion;

[0058] (a4) adding at least one first amino acid or amino acid hydrochloride and a first catalyst, and adjusting the pH of the emulsion or dispersion to 4 to 8;

[0059] (b) carrying out a second polymerization and / or crosslinking step by adding at least one hydroxyl donor;

[0060] (c) obtaining a microcapsule dispersion by adding at least one second amino acid and adjusting the pH of the emulsion or dispersion to between 4 and 8, in particular at a temperature of at least 60° C., and performing a third polymerization and / or crosslinking step;

[0061] (d) optionally adding additional catalyst and adjusting the pH of the microcapsule dispersion to between 4 and 7;

[0062] (e) curing the microcapsule dispersion obtained from step (c) or (d) at a temperature of at least 60° C. for at least 60 minutes;

[0063] (f) adding at least one release agent and incorporating the release agent into the microcapsule shell;

[0064] (g) post-curing the microcapsules obtained in step (f);

[0065] And optionally:

[0066] (h) separating the microcapsules from the microcapsule dispersion, and if necessary, drying the microcapsules or adjusting the viscosity of the microcapsule slurry by adding a thickener.

[0067] 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 synonymous.

[0068] Within the scope of the present invention, the capsule shell or capsule wall is preferably composed of a plurality of crosslinked matrices or crosslinked units, which preferably have different compositions and are generated in the preparation of the microcapsules according to the invention by a plurality of method steps or process sequences, in particular a crosslinking step, so that a three-dimensional network is formed.

[0069] A crosslinked matrix or crosslinking unit in the context of the present invention is a complex or network of starting components for building a microcapsule shell, which is built by linear or three-dimensional polymerization and / or crosslinking between functional groups of the starting components and / or with other components of the microcapsule shell and / or into which other components of the microcapsule shell are incorporated. In the method according to the invention, a plurality of crosslinked 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 crosslinked unit or crosslinked matrix as a whole forms a capsule shell or a capsule wall.

[0070] 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, and a mold release agent incorporated into the capsule shell or capsule wall.

[0071] In the first step (a) of the process according to the invention, a first polymerization and / or crosslinking (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.

[0072] The polyurea / polyurethane microcapsules according to the present invention are prepared using at least one or more polyisocyanates.

[0073] At least one isocyanate or polyisocyanate having two or more isocyanate groups used in a method for preparing biodegradable polyurea / polyurethane microcapsules according to the present invention has at least two isocyanate groups for forming a polymer network by polymerization, which forms a capsule shell or a capsule wall.

[0074] 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 refer to compounds containing 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 more isocyanate groups (-N=C=O) in the molecule. Polyisocyanates having two isocyanate groups are also called diisocyanates.

[0075] 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.

[0076] Polyisocyanates, especially aromatic polyisocyanates, are very 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.

[0077] 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.

[0078] 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.

[0079] In a preferred embodiment of the process according to the invention, the polyisocyanates contain on average 2 to 5 functional -N=C=O groups. These include, for example, aliphatic, cycloaliphatic and aromatic diisocyanates, triisocyanates and higher polyisocyanates.

[0080] Among the above-mentioned polyisocyanates, diisocyanates and polyisocyanates having three functional -NC=O groups are particularly preferred and can therefore be preferably used in the practice of the present invention. Diisocyanates having 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.

[0081] In a preferred embodiment of the method according to the invention, at least one polyisocyanate with two or more isocyanate groups is selected from aliphatic polyisocyanates and / or aromatic polyisocyanates. In a more preferred variant of the method according to the invention, at least one polyisocyanate is a combination of two different aliphatic polyisocyanates, or a combination of aliphatic and aromatic polyisocyanates.

[0082] 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.

[0083] In a preferred variant of the process according to the invention, the polyisocyanate is an aliphatic polyisocyanate.

[0084] The term "aliphatic polyisocyanate" refers to any non-aromatic polyisocyanate molecule. In addition, the polyisocyanate molecule includes 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.

[0085] 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, for example including 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.

[0086] Preferably, the linear aliphatic polyisocyanate molecules are 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 molecules do not include aromatic structures.

[0087] Preferably, the branched aliphatic polyisocyanate molecules are selected from C2 to C20 branched alkyl groups, preferably C3 to C15 branched alkyl groups, C4 to C12 branched alkyl groups, C5 to C10 branched alkyl groups, C6 to C9 branched alkyl groups and C7 to C8 branched alkyl groups.

[0088] The shorter the carbon chain of the polyisocyanate molecule, the higher the reaction rate compared to its long-chain analogues.

[0089] Cyclic aliphatic polyisocyanate molecules include at least 1, i.e. 1, 2, 3, 4 or more non-aromatic ring structures, wherein the ring structure itself is preferably composed of only carbon atoms. Of course, the carbon atoms of the ring structure may have suitable substituents. Preferably, at least one ring structure is independently composed of 3, 4, 5, 6, 7 or 8 rings. Preferably, the cyclic aliphatic molecule includes 2 to 20 carbon atoms, such as 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.

[0090] In another variant of the method 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 includes, for example, phenyl, tolyl, xylyl, naphthyl or diphenyl units as aromatic components, and derivatives of such polyisocyanate compounds.

[0091] Aromatic polyisocyanates react significantly faster than aliphatic polyisocyanates and are therefore preferably used in the process of the invention.

[0092] Straight chain, branched or cyclic aliphatic or aromatic polyisocyanates can exist as monomers or polymers, respectively. 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, 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.

[0093] 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, 140g / 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.

[0094] Any 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.

[0095] Preferably, derivatives of linear, 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 linear or branched aliphatic polyisocyanates. Preferred oligomers are biuret, isocyanurate, uretdione, imino-oxadiazinedione, 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.

[0096] Preferably, the aliphatic polyisocyanates are present exclusively in monomeric form and / or in dimeric form (as isocyanates) or in oligomeric form.

[0097] Derivatives of linear, branched or cyclic polyisocyanates and / or mixtures thereof can also be obtained by reacting polyisocyanates with polyols (eg glycerol), polyamines and polythiols (eg dimercaptopropanol).

[0098] 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).

[0099] Exemplary aliphatic polyisocyanates include those commercially available, such as BAYHYDUR N304 and BAYHYDURN 3Q5, which are aliphatic water-dispersible polyisocyanates based on hexamethylene diisocyanate; DESMODUR N3400, 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.

[0100] 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.), hexamethylene diisocyanate (HDI), lysine triisocyanate and lysine diisocyanate ethyl ester and derivatives thereof, preferably wherein any of the derivatives comprises more than one isocyanate group and, where appropriate, 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(s) 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. 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, one or more groups selected from the group consisting of: H6XDI, in particular Takenate D-120N of Mitsui Chemicals, Inc., biuret, isocyanurate, uretdione, imino-oxadiazinedione and trimethylolpropane adducts (such as TMP adducts).

[0101] 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.

[0102] Other suitable commercially available polyisocyanates include LUPRANAT M20 (BASF), wherein the average n is 0.7; PA PI 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., Ltd.), DESMODUR L75 (Bayer AG) and DESMODUR IL (Bayer AG).

[0103] In a preferred variant, the polyisocyanate used for preparing the polyurea / polyurethane microcapsules according to the invention is used as a single polyisocyanate component, ie without addition of further different polyisocyanate components.

[0104] Examples of polyisocyanate monomers which can be used according to the invention and which contain at least two polyisocyanate groups 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, 1,6-tetramethylene diisocyanate, 1,6-hexamethyl diisocyanate, 1,6-tetramethylene ... ,4-phenylene diisocyanate, a mixture of 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, p-phenylene diisothiocyanate, xylylene-1,4-diisothiocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, xylylene-1,4-diisocyanate and xylylene-1 ,3-diisocyanate mixture, 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-diisocyanate benzene, 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.

[0105] Industrially prepared diisocyanates and polyisocyanates are preferably used as polymerizable compounds having at least two polyisocyanate groups, for example TDI: toluene diisocyanate (mixture of isomers of 2,4- and 2,6-toluene diisocyanate in a ratio of 80:20); HDI: hexamethylene diisocyanate-(1,6); IPDI: isophorone diisocyanate or DMDI: diphenylmethane-4,4′-diisocyanate.

[0106] 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.

[0107] 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 diisocyanate and tetraalkyl diphenylmethane diisocyanate, 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-diisocyanate-2,4,4-trimethylhexane, 1-isocyanatemethyl-3-isocyanate-1,5,5-trimethylcyclohexane, chlorinated and brominated diisocyanates, phosphorus-containing diisocyanates, 4,4'-diisocyanatephenylperfluoroethane, 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-1,2-bromo-3,3-bischloromethylether-4,4'-diphenyl diisocyanate.

[0108] Surprisingly, in particular the use of long-chain aliphatic diisocyanates having 6, 7, 8, 9, 10 or even more carbon atoms results in a more stable capsule shell or capsule wall.

[0109] 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.

[0110] Derivatives of polyisocyanates which are prepared by known methods by modifying the abovementioned diisocyanates or mixtures thereof 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.

[0111] 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.

[0112] This combination exploits the different reaction rates of polyisocyanates: aromatic polyisocyanates react significantly faster than aliphatic polyisocyanates, and for short-chain aliphatic polyisocyanates, i.e. aliphatic polyisocyanates having 1 to 5 carbon atoms, preferably 3 to 5 carbon atoms, the reaction rate is higher compared to long-chain analogs.

[0113] In another preferred embodiment of the invention, the different aliphatic and / or aromatic polyisocyanates also have different chain lengths. In this context, preferably, long-chain polyisocyanates have 6, 7, 8, 9, 10, 11, 12, 13, 14, 20, 25 or more carbon atoms, but more preferably, long-chain polyisocyanates have 6 to 12 carbon atoms, particularly preferably 6 to 8 carbon atoms. Short-chain polyisocyanates are polyisocyanates having 1 to 5 carbon atoms, preferably polyisocyanates having 3 to 5 carbon atoms.

[0114] 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.

[0115] 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, for the preparation of the biodegradable microcapsules according to the invention.

[0116] In this regard, aliphatic polyisocyanates are particularly preferred due to their chemical relationship with bio-based systems. For example, lysine and 1,5-diisocyanate pentane both produce the same degradation product 1,5-diaminopentane and are therefore particularly suitable for preparing bio-based and biodegradable microcapsules from an environmental perspective.

[0117] 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.

[0118] Examples of preferred specific mixtures of at least one aliphatic polyisocyanate and at least one aromatic polyisocyanate are mixtures of hexamethylene diisocyanate biuret with trimethylol adduct of xylylene diisocyanate, mixtures of hexamethylene diisocyanate biuret with diisocyanate polyisocyanurates or mixtures of hexamethylene diisocyanate biuret with trimethylolpropane adduct of toluene diisocyanate.

[0119] It is more preferred according to the present invention if, 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.

[0120] Preferably, for use in the method according to the invention, the following combination results:

[0121] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0122] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and long-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0123] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aromatic polyisocyanates (monomers or oligomers or polymers);

[0124] - short-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and long-chain aromatic polyisocyanates (monomers or oligomers or polymers);

[0125] - long-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0126] - long-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and long-chain aliphatic polyisocyanates (monomers or oligomers or polymers);

[0127] - long-chain aliphatic polyisocyanates (monomers or oligomers or polymers) and short-chain aromatic polyisocyanates (monomers or oligomers or polymers);

[0128] - long-chain aliphatic polyisocyanates (monomers) and long-chain aromatic polyisocyanates (oligomers and polymers);

[0129] The definitions of short and long chains described previously are used.

[0130] 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 and aromatic polyisocyanates, can significantly improve stability and performance (fragrance release in the case of fragrance capsules) due to differences in reaction rates, dissociation and crosslinking structures of the polyisocyanate components.

[0131] 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.

[0132] Thus, the process described herein can be used to prepare microcapsules with high performance (fragrance release) from mixtures of aliphatic and aromatic polyisocyanates or from mixtures of two different aliphatic polyisocyanates. Such microcapsules are very stable and are characterized by outstanding aroma preservation properties, which in turn manifest themselves in better capsule performance (fragrance release), for example in the field of flavor or fragrance encapsulation.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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, polyurea / polyurethane microcapsules with a polyisocyanate content of only 0.6% by weight (relative to the total weight of the capsule wall) can be prepared using the process according to the invention. 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.

[0138] In step (a1) of the method for preparing microcapsules according to the invention, at least one polymerizable polyisocyanate comprising at least two or more functional isocyanate groups is firstly substantially dissolved in an optionally inert non-aqueous solvent or a mixture of inert non-aqueous solvents together with at least one or more active substances to be encapsulated. "Substantially dissolved" is to be understood as at least 90% by weight, preferably at least 98% by weight, even more preferably 99.9% by weight of the above components being dissolved in a solvent or a solvent mixture so that it can be used in the present method. Preferably, at least one polyisocyanate and at least one active substance to be encapsulated are completely dissolved in the solvent or the solvent mixture. If the solvent does not ensure sufficient dissolution of the isocyanate, this disadvantage can be overcome by using a suitable solubility promoter.

[0139] 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.

[0140] 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, ME 18SD-F, ME 12C-F, 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, palmitic acid Stearyl alcohol 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, stearic acid oil Esters, 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.

[0141] 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, 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 hydrocarbons or cycloalkanes, for example squalane, squalene or dialkylcyclohexanes and / or mineral oil.

[0142] 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, C6 to C22 linear or branched fatty alcohols, in particular dioctyl malate, esters of linear or branched fatty acids with polyols, for example 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, especially 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 dicaprylyl carbonate (Cetiol TM CC), Guerbet carbonates based on fatty alcohols having 6 to 18, preferably 8 to 10, carbon atoms, benzoates 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 dioctyl ether (Cetiol TM OE), ring-opening products of epoxidized fatty acid esters with polyols, silicone oils (cyclomethicone and polymethicone grade polysiloxanes etc.) and / or aliphatic hydrocarbons or cycloalkanes, such as squalane, squalene or dialkylcyclohexanes.

[0143] 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.

[0144] Particularly advantageously suitable inert solvents 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 mixtures 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.

[0145] The abovementioned solvents are used in the process according to the invention either individually or as a mixture of two or more solvents.

[0146] In an alternative and preferred variant of the process according to the invention, at least one polyisocyanate is dissolved directly in the solution of the at least one active substance, preferably one or more fragrances or flavorings / fragrances or flavorings or fragrance oils, so that essentially no solvents as mentioned 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.

[0147] 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 solvent content of the fragrance or flavoring solution is less than 30%. More preferably, the fragrance or flavoring solution contains less than 20%, 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.

[0148] In the method according to the invention, the active substance to be encapsulated or the core material for preparing the microcapsules according to the invention can in principle be any material suitable for being encapsulated in the microcapsules. The active substance to be encapsulated is a lipophilic, water-insoluble or water-immiscible liquid or solid as well as a suspension. This ensures that during the preparation of the microcapsules according to the invention, the active substance to be encapsulated is in the internal non-aqueous phase and does not mix with the external 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 the core material during the subsequent emulsification and crosslinking of the capsule wall components. The internal non-aqueous phase formed in this way is characterized by its organic hydrophobic and oily characteristics.

[0149] 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 substance from the group of pesticides, biocides, insecticides, 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.

[0150] In a preferred variant of the invention, in particular lipophilic fragrances or fragrance mixtures consisting of two or more fragrances (fragrance oils), or flavorings or flavoring mixtures consisting of two or more flavorings (essences), or even biotin, are considered as lipophilic active substances.

[0151] 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 a group of hydrocarbons; 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-butenoates of acyclic terpene alcohols; acyclic terpene aldehydes and ketones and their dimethyl and diethyl acetals; cyclic terpene alcohols formate, acetate, propionate, isobutyrate, butyrate, isovalerate, valerate, hexanoate, crotonate, tiglate 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; esters of alicyclic alcohols; esters of alicyclic carboxylic acids; 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.

[0152] Suitable fragrances and flavoring agents 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.

[0153] Preferably, the microcapsules according to the present invention have 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:

[0154] - 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;

[0155] - 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;

[0156] - 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;

[0157] - 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;

[0158] - 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;

[0159] - 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;

[0160] - 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;

[0161] - 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;

[0162] 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-dimethyl lactanal;

[0163] - 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;

[0164] -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);

[0165] -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;

[0166] - 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;

[0167] - 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;

[0168] - 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;

[0169] - alicyclic 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;

[0170] -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;

[0171] - esters of cycloaliphatic alcohols, such as 1-cyclohexylethyl crotonate;

[0172] - esters of alicyclic 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; - aromatic hydrocarbons, such as styrene and diphenylmethane;

[0173] - 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;

[0174] - 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;

[0175] - 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;

[0176] - 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;

[0177] - 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;

[0178] - 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;

[0179] - 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;

[0180] -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;

[0181] -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.

[0182] 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.

[0183] 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; damascone ; Decanolide; 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 methyl butyrate; Ethyl propionate; Eucalyptol; Eugenol; Ethyl heptanoate; 4-(p-hydroxyphenyl)-2-butanone; γ-decanolide; Geraniol; Geranyl acetate; Geranyl acetate; Grapefruit aldehyde; 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. ;

[0184] Among the abovementioned individual fragrances which can be encapsulated in the sense of the present invention, preference is given to using fragrances having aldehyde, carboxylic acid or ester functionality.

[0185] Aldehyde fragrances, including the corresponding acetals, esters and lactones, can be divided into the following categories, namely

[0186] (i) fatty aldehydes and their acetals;

[0187] (ii) alicyclic aldehydes;

[0188] (iii) aromatic aldehydes or aromatic aliphatic aldehydes;

[0189] (iv) aliphatic, aromatic or araliphatic esters; and

[0190] (v) lactones;

[0191] and mixtures thereof.

[0192] The above-mentioned fragrances having aldehyde, carboxylic acid or ester functions and mixtures thereof are selected from one or more of the following groups:

[0193] - 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;

[0194] - 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;

[0195] - 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;

[0196] - 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;

[0197] -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;

[0198] - 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;

[0199] - 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;

[0200] - 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.

[0201] Listed below are aldehydes, acetals, esters and lactones and their commercial names which are particularly preferred as representatives of groups (i) to (v) in the sense of the process according to the invention:

[0202] Aldehydes: 2-methylvaleraldehyde; Aldehyde C12 MNA HM; Aldehyde C4; Aldehyde C5; Aldehyde C6; Aldehyde C7; Aldehyde C8; Aldehyde C9; Aldehyde C10; Aldehyde C11 ISO; Aldehyde C11 MOA pure; Undehyde C11; Aldehyde C 11UNDEYLENIC; Aldehyde C12; Aldehyde C12 MNA; Aldehyde C13; Red orange aldehyde; Amyl cinnamaldehyde α; Anisealdehyde-O; Anisealdehyde; Natural benzaldehyde; Bergamot aldehyde; Boric aldehyde; Bojie red aldehyde; Camphor aldehyde; Citral; Citronellal HM; Citronelloloxyacetaldehyde; White 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;

[0203]

[0204] In another alternative embodiment, 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 in the polyurea / polyurethane microcapsules according to the invention. This is a composition containing at least one fragrance or one flavoring. Such a composition, in particular a fragrance mixture or a fragrance oil, preferably comprises 2, 3, 4, 5, 6, 7, 8, 9, 10 or more fragrances. 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; young leaf water absolute (Eau de brouts-Absolü); 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; guaya balsam; guaya balsam oil; helichrysum absolute; helichrysum oil; ginger oil; orris root absolute; orris root oil; jasmine absolute; calamus oil; chamomile oil indigo; Roman yew oil Chamomile oil; carrot seed oil; kali oil; pine needle oil; curly mint oil; coriander oil; labdanum oil; labdanum absolute; labdanum resin; lavender absolute; lavender oil; lavender absolute; lavender oil; lemongrass oil; lovage oil; distilled white lemon oil; pressed white lemon oil; camphor oil; litsea cubeba oil; laurel oil; bay leaf oil; mace oil; marjoram oil; tangerine oil; mace bark oil Mimosa Absolute; Musk Seed Oil Musk tincture; Muskateller- ); 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; Perilla oil; Peru balsam oil; Parsley leaf oil; Parsley seed oil; Petitgrain oil; Peppermint oil; Allspice oil; Pine oil; Peppermint oil Rose absolute; Rosewood oil; Rose oil; Rosemary oil; Dalmatian sage oil; Spanish sage oil; Sandalwood oil; Celery seed oil; Spike lavender oil Anise oil; styrax oil; marigold oil; fir needle oil; tea tree oil; turpentine oil; thyme oil; tolubalsam; 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.

[0205] 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 acetate, menthyl isobutyrate), menthyl esters (e.g., menthyl acetate, menthyl esters ... esters, 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 mixtures thereof), half esters of menthol and dicarboxylic acids or derivatives thereof (e.g. monomenthyl succinate, monomenthyl glutarate, monomenthyl malonate, o-menthyl succinate-N,N-( 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 include 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 cooling mouthfeel effect. Suitable cooling agents are well known in the art, for example, described in US 2017 / 216802 (A1), US 2010 / 273887 (A1), EP 2 033 688 (A2) and EP 1 958 627 (A2).

[0206] In another variant, TRPV1 or TRPV3 modulators are used as active substances or core materials to be encapsulated in the polyurea / polyurethane microcapsules according to the invention. TRPV1 and TRPV3 modulators are known in the prior art and are related to TRP channels (transient receptor potential channels) of the vanilloid (TRPV) subfamily. TRPV1 modulators impart a spicy taste and a 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 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.

[0207] In another variant of the polyurea / polyurethane microcapsules according to the invention, as active substance to be encapsulated or as core material, an active substance selected from a group of substances 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 or stinging sensation in the mouth or throat, or substances with a stimulating or pungent or astringent effect.

[0208] Preferably, the active substance causing heat or irritation 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 (Aframomummelegueta), 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] or 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.

[0209] The active substances perceived as irritating or pungent are preferably 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.

[0210] 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; 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-piperidin (achilleamid); 2E,4E-decadienoic acid-N-piperidin ( 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. ;

[0211] 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, thearubigenine, 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 their reaction products, such as elligatannin, aluminum salts, such as alum, and mixtures thereof.

[0212] In another variant of the method of the invention, the biogenin may also be encapsulated as a core material, wherein the core material comprises at least one biogenin or a mixture thereof.

[0213] Biosources refer 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.

[0214] In another variant of the method according to the invention, substances used for paper printing coatings 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 incorporated in its entirety into the present description.

[0215] 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, based on the total weight of the inner non-aqueous phase.

[0216] 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.

[0217] 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.

[0218] Furthermore, the first polymerization and / or crosslinking step (a) of the process according to the invention comprises providing an external aqueous phase (a2) comprising at least one protective colloid and optionally an emulsifier.

[0219] For this purpose, the protective colloid and the emulsifier (if necessary) 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.

[0220] 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 and favors the formation of relatively small droplets and thus also the corresponding microcapsules.

[0221] In the context of the process according to the invention, the protective colloid has, in addition to the above-mentioned properties, emulsifying properties. If the emulsifying properties of the protective colloid (e.g. carboxymethylcellulose, acid-modified starches, polyvinyl alcohol, ammonium derivatives of polyvinyl alcohol, polystyrene sulfonates, polyvinyl pyrrolidone, polyvinyl acrylates, etc.) are sufficient, in the process according to the invention it is even possible to advantageously dispense with the use of emulsifiers in the downstream emulsification or dispersion step.

[0222] The protective colloid used in the process according to the invention is selected from the group consisting of:

[0223] - diols, in particular ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, the isomeric butanediols, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol, 1,2-dodecanediol, and

[0224] - polyols, preferably triols, in particular glycerol and ethoxylation products thereof; trimethylolpropane and ethoxylation products thereof; 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,

[0225] - 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,

[0226] - animal and vegetable polymers, in particular gum arabic (Senegal and Seyal types), proteins, gelatin, mastic, shellac, lignin, chitosan, saponins

[0227] and mixtures of the above compounds.

[0228] Preferably, the external aqueous phase comprises 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 derivatives, 1,3,5-trihydroxybenzene or starch, especially modified starch, or animal or plant polymers are used as protective colloids for preparing microcapsules according to the invention.

[0229] 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 biocrosslinkers.

[0230] 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.

[0231] The chemically modified starch is preferably acid-modified starch, alkali-modified starch, oxidized starch, acetylated starch, succinate-ated starch or octenylsuccinate-ated starch.

[0232] According to the invention, combinations of two or more different protective colloids can also be used for the preparation of the microcapsules according to the invention.

[0233] 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 as the additional protective colloid in the external aqueous phase. Due to the large number of functional hydroxyl groups, this combination stabilizes the emulsion and, on the other hand, favors the reaction between the protective colloid and the polyisocyanate, thereby shifting the reaction equilibrium in the reaction of the protective colloid with the polyisocyanate towards the product, i.e. the polyurethane. In addition, the large number of functional hydroxyl groups in starch also enables the formation of particularly sterically pronounced crosslinks.

[0234] Depending on the number of functional groups and / or the size of the protective colloid, the above-mentioned protective colloids exhibit different reaction rates with the isocyanate groups of at least one polyisocyanate. For example, glycerol reacts faster with isocyanate groups than starch due to its size. Therefore, the crosslinking of the protective colloid with the isocyanate groups of the polyisocyanate can be controlled by the choice of the protective colloid.

[0235] The combination of glycerol with starch or 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 properties of the two protective colloids mentioned above: 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 colloids.

[0236] The protective colloid used in the process according to the invention has a dual function, on the one hand as a protective colloid, thereby preventing agglomeration of the emulsified, suspended or dispersed components, stabilizing the subsequently formed emulsion, favoring the formation of small droplets, and stabilizing the finally formed microcapsule dispersion.

[0237] On the other hand, due to 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 in the emulsification step (a3), which contributes to the formation of the capsule wall and becomes a component thereof.

[0238] 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), polymerization and / or crosslinking near the core is formed at the interface between the emulsified or suspended oil droplets of the hydrophobic active substance to be encapsulated (which forms the core of the microcapsule according to the invention) and the outer external phase by interfacial polymerization. The polymerization and / or crosslinking is based on the polyaddition reaction of polyisocyanate and protective colloid (preferably a polyol) to form a capsule shell or capsule wall made of polyurethane, the equation of which is as follows:

[0239] n O=C=NR 1 -N=C=O+n HO-R 2 -OH-→(-R 2 -O-CO-NH-R 1 -NH-CO-O-) n

[0240] This is manifested in the production of gas and the release of carbon dioxide.

[0241] By forming the polymer layer already during the emulsification or dispersion step, the active substance to be encapsulated, in particular active substances with aldehyde, carboxylic acid or ester functions, is 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] 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 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.

[0246] In order to promote the formation of an emulsion or dispersion of an inner non-aqueous phase and an outer aqueous phase, to stabilize the emulsion or dispersion formed, and to prevent the separation of the inner non-aqueous phase (oily / organic / hydrophobic) and the outer aqueous phase (hydrophilic), in the process according to the invention, an emulsifier or an emulsifying auxiliary is optionally added to the outer aqueous phase. The addition of an emulsifier is optional when the protective colloid has no or only low (i.e. insufficient) emulsifying properties. If a protective colloid with an emulsifying effect is used, an emulsifier can advantageously be omitted in the process according to the invention.

[0247] 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 dispersion obtained thereby.

[0248] For example, nonionic surfactants from at least one of the following groups can be used as emulsifiers:

[0249] - 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;

[0250] - alkyl and / or alkenyl oligoglycosides having 8 to 22 carbon atoms in the alkyl(en)yl group and ethoxylated analogs thereof;

[0251] - addition products of 1 to 15 mol of ethylene oxide onto castor oil and / or hydrogenated castor oil;

[0252] - addition products of 15 to 60 mol of ethylene oxide onto castor oil and / or hydrogenated castor oil;

[0253] - partial esters of glycerol and / or sorbitol polyols 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;

[0254] - 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, dodecyl glucoside) and 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

[0255] - 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;

[0256] - mono-, di- and tri-alkyl phosphates and mono-, di- and / or tri-ethylene glycol alkyl phosphates and their salts;

[0257] -Wool wax alcohol;

[0258] - 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;

[0259] - Polyalkylene glycols and glycerol carbonate.

[0260] 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.

[0261] 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 known as cocamidopropyl betaine by CTFA name.

[0262] 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) and can form inner salts in addition to the C8 / 18 alkyl or acyl group in the molecule. 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.

[0263] 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.

[0264] 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 %, respectively, relative to the total weight of the external aqueous phase.

[0265] The protective colloid emulsifier aqueous solution is preferably prepared by adding the protective colloid and optionally the emulsifier to the external aqueous phase in sequence (or vice versa), or adding the protective colloid and optionally the emulsifier to the external aqueous phase simultaneously with stirring.

[0266] It may be advantageous if, for the preparation of polyurea / polyurethane microcapsules according to the invention, the external aqueous phase may contain a dissolved or dispersed stabilizer in order to prevent separation of the internal non-aqueous (oil) phase and the external aqueous phase.

[0267] Preferred stabilizers for preparing 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 (e.g. sold under the name of ), diutan gum, xanthan gum or carboxymethyl cellulose.

[0268] The stabilizer 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, respectively, relative to the external aqueous phase.

[0269] Before mixing the inner non-aqueous phase and the outer aqueous phase, or before emulsifying / dispersing the inner non-aqueous phase in the outer aqueous phase, the pH of the outer aqueous phase is adjusted to an acidic pH in the range of 1 to 5. Preferably, the pH of the outer aqueous phase is adjusted to a range of 3 to 5.

[0270] The pH of the external aqueous phase is adjusted by adding an organic acid. Most preferably, formic acid or acetic acid is used to adjust the pH.

[0271] The oil-in-water emulsion is prepared by mixing an inner non-aqueous phase and an outer aqueous phase. The weight ratio of the inner non-aqueous phase to the outer aqueous phase is preferably in the range of 2:1 to 1:10, even more preferably in the range of 1:2 to 1:4.

[0272] The emulsification of liquid active substances or the dispersion of solid active substances, i.e. the emulsification or dispersion of the internal non-aqueous phase or oily phase in the external aqueous phase or hydrophilic phase, is carried out under high turbulence or strong shearing force. The diameter of the obtained microcapsules can be determined by the intensity of turbulence or shearing. The size of the droplets can be measured by light scattering or microscopic examination. In this case, the preparation of microcapsules can be continuous or discontinuous. As the viscosity of the aqueous phase increases or the viscosity of the oil phase decreases, the size of the obtained capsules usually decreases.

[0273] The process for preparing polyurea / polyurethane microcapsules according to the invention can be carried out, for example, by using a forced metering pump using the "inline" technique, or can also be carried out with stirring in a conventional dispersing or emulsifying apparatus.

[0274] In order to prepare the microcapsules according to the present invention, the emulsification or dispersion of the internal non-aqueous phase in the external aqueous phase is carried out by means of an emulsifying turbine (IKAEurostar 20 high-speed stirrer). 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.

[0275] After the emulsification or dispersion step (a3) ​​is completed, there is an oil-in-water emulsion or dispersion in which the inner oil phase with the active substance to be encapsulated is finely emulsified or dispersed in the form of droplets in the outer water phase.

[0276] 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, likewise under stirring. The first crosslinking is carried out by adding at least one first amino acid or at least one amino acid hydrochloride, preferably in the form of an aqueous solution, in the presence of a catalyst. The addition of the amino acid or amino acid hydrochloride and the catalyst is preferably carried out at a temperature of 20° C. to 30° C.

[0277] At least one first amino acid is selected from the group consisting of arginine, histidine, lysine, tryptophan, ornithine, and mixtures thereof.

[0278] It is generally advantageous to use an amino acid as the hydrochloride. The hydrochlorides of the above amino acids are more soluble in water and thus more soluble in the external aqueous phase. In addition, by using an amino acid as the hydrochloride, the pH of the reaction mixture is converted to acidic, which, in addition to improving solubility, can also be expected to increase the reactivity between the at least one polyisocyanate and the first amino acid, thereby increasing the polymerization and / or crosslinking between the two components.

[0279] 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.

[0280] The amino acids arginine, lysine and ornithine or the corresponding amino acid hydrochlorides are compounds with 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 function in the side chain. Therefore, the above amino acids or their amino acid hydrochlorides exhibit multifunctionality in the polymerization with at least one polyisocyanate.

[0281] Due to the crosslinking between the functional groups of the at least one polyisocyanate and 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.

[0282] Of 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.

[0283] 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.

[0284] The amino acid or amino acid hydrochloride, i.e. the first crosslinking agent, is added to the emulsion or dispersion as such (e.g. in solid form) 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.

[0285] 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.

[0286] 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.

[0287] In order to optimize the polymerization or crosslinking between the at least one polyisocyanate or multiple polyisocyanates and the functional groups of the first amino acid or amino acid hydrochloride, the pH value of the emulsion or dispersion is adjusted to a range of 4 to 8 at the beginning of the reaction. Preferably, the pH value of the emulsion or dispersion is adjusted to a range of 6 to 8.

[0288] The pH of the emulsion or dispersion is adjusted by adding an alkaline aqueous solution. Most preferably, sodium hydroxide or potassium hydroxide is used to adjust the pH.

[0289] In the method according to the present invention, the formation of the first crosslinking unit is based on the polyaddition reaction of polyisocyanate (one or more) with amino acid or amino acid hydrochloride. 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 amino group (-NH 2 ) with the isocyanate groups of at least one polyisocyanate to form:

[0290] n O=C=NR 1 -N=C=O+nH 2 NR 2 -→(-O-NH-R 1 -NH-CO-NH-R 2 -) n

[0291] For the process according to the invention, the first crosslinking matrix or first crosslinking units, in particular polyurea crosslinking units, for building up the capsule shell or capsule wall are formed by interfacial polymerization at the interface of emulsified or dispersed oil droplets containing the lipophilic active substance to be encapsulated.

[0292] By constructing the first cross-linked matrix or the first cross-linked unit, at the interface, the emulsified or dispersed oil droplets with the core material (i.e., the encapsulated active substance) are surrounded by the outer cross-linked matrix or cross-linked unit, thereby generating a capsule wall, making it more difficult for the encapsulated active substance to diffuse.

[0293] Adding the first catalyst to the emulsion or dispersion accelerates the reaction between the polyisocyanate and the amino acid or amino acid hydrochloride and catalyzes the reaction that is favorable to the formation of the polyurea crosslinked matrix.

[0294] The catalyst added in the method according to the present invention is preferably diazabicyclo [2.2.2] octane (DABCO), also known as triethylenediamine (TEDA), a bicyclic tertiary amine. DABCO is generally used as a catalyst for preparing polyurethane plastics. The tertiary amine with a free electron pair promotes the reaction between at least one polymerizable polyisocyanate and the amino group of the first amino acid or amino acid hydrochloride.

[0295] In addition to DABCO, catalysts based on bismuth or tin, for example, are used to catalyze the first crosslinking, for example catalysts based on bismuth(II) salts or based on bismuth(III) salts, as described in KC Frisch & L.P. Rumao, Catalysis in Isocyanate Reactions, Polymer Reviews, 1970, 5:1, pp. 103 to 149, DOI: 10.1080 / 15583727008085365, the disclosure of which in this regard is fully incorporated into the present description.

[0296] Diazabicyclo[2.2.2]octane (DABCO) is particularly preferred as catalyst.

[0297] According to the invention, a combination of DABCO and one of the above catalysts is preferred. Such a mixture leads to a multiplication of the reactivity, as described in KC Frisch & L.P. Rumao, Catalysis in Isocyanate Reactions, Polymer Reviews, 1970, 5: 1, pp. 103 to 149, DOI: 10.1080 / 15583727008085365, the disclosure of which in this regard is fully incorporated into the present specification.

[0298] 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.

[0299] The amount of catalyst added to the emulsion or dispersion is between 0.01 and 1 wt %, preferably between 0.05 and 0.2 wt %, relative to the total weight of the emulsion or suspension. In the case of a slow polymerization reaction, the amount of catalyst required can be adjusted accordingly.

[0300] The ratio of the catalyst in the emulsion or dispersion to the at least one polyisocyanate in the inner non-aqueous phase is preferably in the range of 1:20 to 1:50.

[0301] 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.

[0302] The addition of the first 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 26°C.

[0303] The first polymerization and / or 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, and most preferably within a time period of about 15 minutes.

[0304] 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 capsules prepared without the addition of catalyst, the capsules prepared in this way have a significantly higher stability, even after 10 days at 50°C, and a significant reduction in free fragrance oils.

[0305] Particularly stable capsules were prepared using the catalyst diazabicyclo[2.2.2]octane (DABCO).

[0306] The first polymerization and / or crosslinking step (a) in the process according to the invention is followed by a further, second polymerization and / or crosslinking step (b) for further building up of the capsule shell or capsule wall by adding at least one hydroxyl donor to the oil-in-water emulsion or dispersion obtained in process step (a4).

[0307] 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.

[0308] The hydroxyl donor is selected from the group consisting of glycerol, propylene glycol, 1,3,5-trihydroxybenzene, starch, modified starch, cellulose derivatives such as hydroxyethylcellulose, especially quaternized hydroxyethylcellulose, or carboxymethylcellulose, gum arabic (Senegal type and Seyir type) and mixtures thereof. Glycerol and starch are preferred; glycerol is most preferred.

[0309] The starch used in the method 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.

[0310] The modified starch is preferably a chemically modified starch, ie an acid-modified starch, an alkali-modified starch, an oxidized starch, an acetylated starch, a succinate-ated starch or an octenylsuccinate-ated starch.

[0311] According to the invention, a combination of two different hydroxyl donors as described above can also be used to prepare the microcapsules according to the invention.

[0312] Depending on their size, the above hydroxyl donors have different reaction rates with the isocyanate groups of the at least one polyisocyanate. For example, glycerol reacts faster with isocyanate groups than starch due to its size.

[0313] Therefore, the combination of glycerol with starch or modified starch or glycerol with quaternized hydroxyethylcellulose or gum arabic of the Seychelles type has proven to be particularly advantageous. With such a combination, the properties of the two hydroxyl donors mentioned above can be obtained: on the one hand, the high reaction rate of glycerol and on the other hand, the number of polymerizable functional groups of starch.

[0314] By reacting at least one polyisocyanate and / or isothiocyanate with the hydroxyl groups of the hydroxyl donor, another, i.e., second crosslinking matrix or second crosslinking unit is formed for building or structuring a capsule shell or capsule wall, the structure of which is similar to the above-mentioned polyurethane crosslinking unit composed of polyisocyanate and protective colloid.

[0315] The polyaddition reaction of at least one polyisocyanate with a hydroxyl donor results in the formation of so-called urethane bridges (-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.

[0316] By forming such further polyurethane crosslinking units, the first polyurea crosslinking units formed in the first polymerisation and / or crosslinking step (a4) are further crosslinked and densified.

[0317] In order to obtain particularly effective, dense and stable crosslinking, the second polymerization and / or crosslinking step (b) 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.

[0318] 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.

[0319] In this context, it is worth noting that the addition of the hydroxyl donor in aqueous form 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%.

[0320] The second polymerization and / or crosslinking step (b) in the method according to the invention is followed by another step, namely a third polymerization and / or crosslinking step (c). In this third crosslinking step, at least one further, namely a second amino acid is added as a crosslinking agent to the oil-in-water emulsion obtained in the crosslinking step (b).

[0321] At least one second amino acid is selected from the group consisting of arginine, histidine, aspartic acid, lysine, glycine, alanine, proline, cysteine, glutamine, leucine, serine, tryptophan, valine, threonine, ornithine, uric acid, and mixtures thereof.

[0322] The above-mentioned amino acid is a compound having at least one amino group on a side chain, and thus has a functionality for polymerization and / or crosslinking with at least one polyisocyanate.

[0323] Among the above amino acids, alkaline-reactive amino acids such as arginine, histidine, lysine or hydrochloride analogs thereof are particularly preferred as both the amino acid and the hydrochloride because of their high reactivity and pH value.

[0324] Due to its water solubility, arginine is particularly preferably used as cross-linking agent in the method according to the invention.

[0325] 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.

[0326] The second amino acid or amino acid hydrochloride is added to the emulsion as such (eg in solid form) 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.

[0327] The amount of the at least one second amino acid or amino acid hydrochloride is generally 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.

[0328] In order to optimize the polymerization or crosslinking between the at least one polyisocyanate or multiple polyisocyanates and the functional groups of the second amino acid or amino acid hydrochloride, the pH value of the emulsion or dispersion is adjusted to a range of 4 to 8 at the beginning of the reaction. Preferably, the pH value of the emulsion or dispersion is adjusted to a range of 6 to 8.

[0329] The pH of the emulsion or dispersion is adjusted by adding an alkaline aqueous solution. Most preferably, sodium hydroxide or potassium hydroxide is used to adjust the pH.

[0330] By adding a second amino acid in the presence of the above-mentioned catalyst, a third crosslinking matrix or third crosslinking unit is constructed in the method according to the present invention to construct a capsule shell or capsule wall. These third crosslinking units are based on the polyaddition reaction of a single polymer or oligomer of polyisocyanate (one or more) with an amino acid to form a capsule shell or capsule wall based on a polyurea structure. The polyurea bond or polyurea structure is formed by the amino group (-NH 2 ) formed by polyaddition onto the isocyanate groups of at least one polyisocyanate:

[0331] n O=C=NR 1 -N=C=O+nH 2 NR 2 -+→(-O-NH-R 1 -NH-CO-NH-R 2 -) n

[0332] By constructing 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.

[0333] The addition of the second amino acid or amino acid hydrochloride is preferably carried out at a stirring speed of 500 to 2000 rpm, particularly preferably 1000 to 1500 rpm, and at a temperature of 60 to 80°C, preferably 60°C.

[0334] The third crosslinking in the method according to the invention is carried out 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.

[0335] In order to obtain a particularly effective, dense and stable network of capsule wall components, in a further step (d) an additional catalyst, ie a second catalyst, is optionally added to the emulsion or dispersion.

[0336] In the process according to the invention, the additional catalyst added is preferably p-toluenesulfonic acid, sulfuric acid, germanium oxide or an enzyme catalyst, preferably Candida antarctica lipase B (CALB). Preferably, these catalysts are catalysts that promote ester reactions.

[0337] The addition of an additional catalyst to the emulsion or dispersion preferably accelerates the ester reaction, i.e. the formation of polyester from the crosslinking of the protective colloid, hydroxyl donor and release agent, and further catalyzes the reaction to facilitate the formation of a three-dimensional, dense and stable polyurea and / or polyurethane and / or polyester crosslinked matrix.

[0338] The catalyst is added to the emulsion or dispersion in an amount between 0.01 and 1 wt %, preferably between 0.05 and 0.2 wt %, relative to the total weight of the emulsion or dispersion. In the case of a slow polymerization reaction, the amount of catalyst required can be adjusted accordingly.

[0339] The ratio of catalyst in the emulsion or dispersion to the at least one polyisocyanate in the inner non-aqueous phase is preferably in the range of 1:20 to 1:50.

[0340] 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.

[0341] The addition of the additional catalyst is preferably carried out at a stirring speed of 500 to 2000 rpm, particularly preferably at 1000 to 1500 rpm, and at a temperature of 20 to 30° C., preferably at 22 to 26° C. In the process according to the invention, the crosslinking promoted or accelerated by the additional catalyst is continued for about 10 to 20 minutes, preferably 12 to 18 minutes, most preferably about 15 minutes.

[0342] By the combination of a first polymerization or crosslinking step between polyisocyanate and the first amino acid, a second polymerization or crosslinking step between polyisocyanate and the hydroxyl donor, and a third polymerization or crosslinking step between polyisocyanate and the second amino acid, polyurea and polyurethane crosslinking units or crosslinking matrices can be generated, which build the capsule shell and the capsule wall. In addition, in the method according to the invention, by successive crosslinking steps, the first, second and third polyurea and polyurethane crosslinking units are further crosslinked spatially with each other and with each other. By the optional combination with additional catalysts, in addition to the above-mentioned polyurea and polyurethane crosslinking units, polyester crosslinks are also generated, which also lead to further crosslinking, thereby building a three-dimensional, dense and stable capsule shell or capsule wall of the microcapsule.

[0343] The greater the number of crosslinking functional groups, the greater the degree of spatial crosslinking, and the denser and more stable the capsule shell or capsule wall of the resulting microcapsules. In addition to the number of functional groups, the chain length of the individual components also has a great influence on the mechanical properties, i.e. the stability, of the capsules. For example, the large number of hydroxyl groups in starch enables particularly spatially pronounced crosslinking. Longer chain capsule shell or capsule wall components, such as polyisocyanates, lead to more stable capsule shells or capsule walls.

[0344] During the above cross-linking step, the stirring power is reduced, preferably to a stirring speed of about 800 to 1200 rpm, so as not to immediately destroy the cross-linked units forming the capsule shell.

[0345] After the third polymerization or crosslinking step and complete crosslinking and structuring 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.

[0346] After crosslinking, the microcapsules in the slurry still have a flexible shell, which is not particularly stable and can therefore break easily. For this purpose, the shell of the microcapsules is cured. Preferably, the curing is achieved by gradually increasing the microcapsule dispersion to a temperature of at least 60° C., preferably in the range of 60 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.

[0347] It is also advantageous to add substances for curing to the external aqueous phase. For this purpose, natural plant tannins of the tannin class are used, which tannins are proanthocyanidins from a chemical point of view and are found in particular in tropical and subtropical dicotyledonous perennials, shrubs and leaves. 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.

[0348] After the curing step (e) of the process according to the invention, in a further process step (f), at least one release agent is added to the microcapsule dispersion or microcapsule slurry, which release agent adheres to the surface of the microcapsule shell or microcapsule wall or is preferably incorporated into the microcapsule shell or microcapsule wall.

[0349] Release agents are usually liquid or pasty substances that prevent adhesion between two materials. In the case of the present invention, the substances are incorporated into the microcapsule shell or microcapsule wall, respectively, and form ionic or even covalent bonds with the existing crosslinked structure of the capsule material via functional groups, such as OH groups or COOH groups.

[0350] The at least one release agent used in the process according to the invention is selected from the group consisting of fatty acids, fatty alcohols, fatty acid esters and animal and vegetable waxes.

[0351] Fatty acids are aliphatic monocarboxylic acids, mostly with unbranched carbon chains. Fatty acids differ in the number of carbon atoms (chain length), and unsaturated fatty acids also differ in the number and position of double bonds. Based on their chain length, fatty acids can be divided into short-chain fatty acids (maximum 6 to 8 carbon atoms), medium-chain fatty acids (8 to 12 carbon atoms), and long-chain fatty acids (13 to 21 carbon atoms).

[0352] Fatty alcohols are aliphatic, long-chain, monovalent, mostly primary alcohols. The hydrocarbon residues in natural fatty alcohols are usually unbranched, and synthetic fatty alcohols are also usually branched. The carbon chain has 6 to 30 carbon atoms and can be monounsaturated or polyunsaturated. Fatty alcohols are present in natural waxes as carboxylic acid esters, for example in wool wax or spermaceti, and are usually called wax alcohols.

[0353] Wax is an organic compound that melts above about 40°C and then forms a low-viscosity liquid. Waxes can vary greatly in their chemical composition and origin. The main components of these mixtures are esters of fatty acids with long-chain aliphatic primary alcohols, so-called fatty alcohols. These esters differ structurally from fats and fatty oils, which are triglycerides containing fatty acids. In addition, such waxes contain free, long-chain aliphatic carboxylic acids, ketones, alcohols and hydrocarbons. Waxes can be of animal or vegetable origin.

[0354] The at least one release agent in the process according to the invention is preferably selected from the group consisting of:

[0355] - long-chain, aliphatic, linear or branched, saturated or unsaturated carboxylic acids (fatty acids) having 12 to 30 carbon atoms, in particular lauric acid (12:0), tridecanoic acid (13:0), myristic acid (14:0), pentadecanoic acid (15:0), palmitic acid (16:0), heptadecanoic acid (17:0), succinic acid (18:0), succinic acid (19:0), succinic acid (20:0), succinic acid (21:0), succinic acid (22:0), succinic acid (23:0), succinic acid (24:0), succinic acid (25:0), succinic acid (26:0), succinic acid (27:0), succinic acid (28:0), succinic acid (29:0), succinic acid (30:0), succinic acid (31:0), succinic acid (32:0), succinic acid (33:0), succinic acid (34:0), succinic acid (35:0), succinic acid (36:0), succinic acid (37:0), succinic acid (38:0), succinic acid (39:0), succinic acid (40:0), succinic acid (41:0), succinic acid (42:0), succinic acid (43:0), succinic acid (44:0), succinic acid (45:0), succinic acid (46:0), succinic acid (47:0), succinic acid (48:0), succinic acid (49:0), succinic acid (50:0), succinic acid (51:0), succinic acid (52:0), succinic acid (53:0), succi (17:0), stearic acid (18:0), nonadecanoic acid (19:0), arachidic acid (20:0), heneicosanoic acid (21:0), behenic acid (22:0), lignoceric acid (24:0), cerotic acid (26:0), montanic acid (28:0) and melissic acid (30:0); myristoleic acid (14:1), palmitoleic acid (16:1), heptadecenic acid (17:1), octadecenoic acid (18:1), oleic acid (18:1), elaidic acid (18:1), vaccenic acid (18:1), gadoleic acid (20:1), gentian acid (20:1), cetyl oleic acid (22:1), erucic acid (822:1), nervonic acid (24:1),

[0356] Linoleic acid (18:2), α-linolenic acid (18:3), γ-linolenic acid (18:3), calendula acid (18:3), punicic acid (18:3), α-eleostearic acid (18:3), β-eleostearic acid (18:3), octadecatetraenoic acid (18:4), arachidonic acid (20:4), eicosapentaenoic acid (20:5), docosatetraenoic acid (ADA) (22:4), docosapentaenoic acid (DPA-3) (22:5), docosahexaenoic acid (22:6) and tetracosahexanoic acid (24:6); phytanic acid;

[0357] - long-chain, aliphatic, straight-chain or branched, saturated or unsaturated primary alcohols (fatty alcohols) having 12 to 30 carbon atoms, in particular lauryl alcohol (12:0), myristyl alcohol (14:0), palmityl alcohol (16:0), margaryl alcohol (17:0), stearyl alcohol (18:0), arachidyl alcohol (20:0), behenyl alcohol (22:0), lignoceryl alcohol (24:0), ceryl alcohol (26:0), montanyl alcohol (28:0) and myristyl alcohol (30:0); palmitoleyl alcohol (16:1), oleyl alcohol (18:1), elaidic alcohol (18:1), linoleyl alcohol (18:2), gamma-linolenic alcohol (18:3);

[0358] - esters of long-chain aliphatic saturated carboxylic acids having 12 to 30 carbon atoms and long-chain aliphatic primary alcohols having 12 to 30 carbon atoms, in particular lauryl palmitate, myristyl palmitate, cetyl arachidate and stearyl behenate; and

[0359] - animal and vegetable waxes, in particular wool wax, china wax, beeswax, sunflower wax, rice bran wax, carnauba wax, pinova wax, rapeseed wax, soy wax, candelilla wax, jojoba oil, cork wax, guarana wax, cotton wax, flax wax, peat wax, rose wax, jasmine wax, pumpkin pita wax and myrtle wax, fig wax, berry wax;

[0360] and mixtures of two or more of the above release agents.

[0361] Among the above carboxylic acids, saturated fatty acids are preferred. The use of the above-specified animal and vegetable waxes is most preferred in the process according to the invention because of their lower melting points, which facilitate their incorporation into the microcapsule shell or microcapsule wall.

[0362] At least one release agent has a dual function. The incorporation of a release agent into the microcapsule shell or microcapsule wall and the formation of ionic or covalent bonds between the release agent and the crosslinking units or the crosslinking matrix lead, on the one hand, to a further stabilization of the microcapsule shell. On the other hand, by incorporating a release agent into the microcapsule shell or microcapsule wall, predetermined breaking points for the degradability of the microcapsule shell are generated, i.e. points in the microcapsule wall, which are designed such that degradation of the microcapsule material occurs first at these points. The degradability of the microcapsule shell or microcapsule wall is thereby promoted. Furthermore, the use of a release agent which stabilizes the microcapsule shell or microcapsule wall also enables the reduction of other capsule wall materials which are less biodegradable or not biodegradable at all.

[0363] The release agent is added to the microcapsule dispersion or microcapsule slurry in an amount of 1-10% by weight relative to the capsule shell. Preferably, the release agent is added in an amount of 2-5% by weight relative to the capsule shell.

[0364] At least one release agent is added to the microcapsule dispersion or microcapsule slurry obtained from process step (e) at a temperature of at least 60° C. up to the boiling point of the microcapsule dispersion, preferably at a temperature of 80° C. At this temperature, the release agent is in the liquid or molten state and can therefore easily fuse and be incorporated into the existing crosslinked structure of the microcapsule shells.

[0365] After adding at least one release agent, the polyurea / polyurethane microcapsules obtained in step (g) are subjected to a post-curing step, preferably at a temperature of at least 60° C. to 100° C. for a period of 60 to 240 minutes.

[0366] 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.

[0367] In order to prevent separation 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.

[0368] The thickener is preferably xanthan gum, diuthan gum, carboxymethyl cellulose (CMC), microcrystalline cellulose (MCC) or guar gum.

[0369] 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.

[0370] Preference is given to using 1,2-hexanediol, 1,2-octanediol or parmetol as preservatives.

[0371] Alternatively, the microcapsules are isolated and dried for storage purposes.

[0372] 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, and in particular 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 in the dispersion can be about 50 to about 150% by weight, preferably about 80 to about 120% by weight, relative to the capsule mass.

[0373] The spray drying itself can be carried out continuously or batchwise in conventional spray equipment with an inlet temperature of about 170 to about 200°C, preferably about 180 to 185°C, and an outlet temperature of about 70 to about 80°C, preferably about 72 to 78°C.

[0374] 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 proportion of core material. On the other hand, the capsules must have a sufficient proportion of capsule wall material to ensure the stability of the capsules.

[0375] According to the invention, it has proven particularly advantageous if the microcapsules are designed with a weight ratio of core material to capsule wall material of 50:50 to 90:10, preferably 70:30 to 80:20.

[0376] 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.

[0377] 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 the hydroxyl donor, and arginine is used as the second amino acid. DABCO is used as a catalyst, modified starch is used as a protective colloid; beeswax is added as a release agent. The pH value of the aqueous phase before the emulsification step and the pH value of the emulsion or dispersion at the beginning of the reaction are both adjusted to 5.5.

[0378] To determine the particle size, the microcapsules according to the invention were dispersed in water within the scope of a dynamic process and the particle size was then determined by means of laser diffraction. The laser beam refracts differently for different capsule sizes and can therefore be converted to size. The Mie theory was used. The particle size measurement was performed using a Malvern Particle Size Analyzer 3000.

[0379] The microcapsules according to the present invention are characterized in that their particle size distribution is between 10 μm and 100 μm at a d(0.5) value, preferably between 20 μm and 65 μm at a d(0.5) value. The corresponding particle size distributions of the microcapsules according to the present invention and the microcapsules of the prior art are as follows: Figure 2 shown.

[0380] A direct comparison of the microcapsules shows that the process according to the invention can achieve the same particle size distribution as microcapsules from the prior art, which are based on a polyurea / polyurethane structure without a release agent and are produced at a pH of 9.

[0381] Figure 3Infrared images of microcapsules according to the present invention and microcapsules of the prior art are shown.

[0382] 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 the hydroxyl donor, and arginine is used as the second amino acid. DABCO is used as a catalyst, modified starch is used as a protective colloid; beeswax is added as a release agent. The pH value of the aqueous phase before the emulsification step and the pH value of the emulsion or dispersion at the beginning of the reaction are both adjusted to 5.5. The microcapsules of the prior art are polyurea / polyurethane-based microcapsules without a release agent, which are prepared under conditions of pH 9.

[0383] The following figure shows the obvious differences between the bands, especially in the fingerprint region. -1 Vibration within the range indicates -CH 2 Group. At 1050cm -1 At 1170 cm-1, a band can be seen that is more intense than in the prior art, which is attributed to polyurethane and polyester. The polyester originates from the ester bonds of octenyl succinate-esterified starch on the one hand and from the ester bonds of release agents (e.g. wax) on the other hand. -1 The band at 1750cm can be classified as polyester. -1 The vibration at 2500 to 3000 cm-1 indicates that the proportion of carbonyl carbon increases significantly. -1 The double vibrations in the range indicate that the release agent leads to an increase in the proportion of carbon chains. Comparison of the infrared spectra further shows that both the microcapsules according to the invention and the microcapsules of the prior art consist of polyurea / polyurethane polymers.

[0384] Furthermore, an advantageous feature of the process according to the invention for preparing polyurea / polyurethane microcapsules is that the individual crosslinking steps are carried out in a pH-dependent manner.

[0385] By optimizing the pH in the emulsification and crosslinking steps of the method according to the invention, it is possible to produce microcapsules with better production performance than without pH adjustment, i.e. without loss or impairment of the functions of the microcapsules, such as olfactory properties and positive secondary properties, such as high stability, i.e. the ability to retain active substances. By means of targeted pH adjustment, the stability can be increased, thereby reducing the free oil content and improving the organoleptic properties of the microcapsules.

[0386] According to the method of the present invention, defined crosslinking units or crosslinking matrices based on polyurea and polyurethane can be alternately deposited around the core containing the lipophilic active substance by interfacial polymerization, thereby producing a stable and dense structure of the capsule wall or capsule shell. The main component of the capsule shell or capsule wall is essentially a polyurea or polyurethane crosslinking matrix or crosslinking unit. In addition, a protective colloid (e.g. starch) can be present in the capsule shell or capsule wall via a polyurethane bond. The incorporation of a release agent in the capsule shell or capsule wall can further stabilize and densify the capsule shell or capsule wall.

[0387] Furthermore, the method according to the invention is characterized in that the protective colloid, the amino acid, the hydroxyl donor as the main component and the polyisocyanate are preferably polymerized and / or cross-linked by a specific catalytic mechanism, thereby enabling the preparation of bio-based and biodegradable microcapsules based on biocompatible polymers. Unlike the microcapsules in the prior art, in which the polyisocyanate accounts for a large proportion of the capsule shell material, the situation here is completely opposite. In the microcapsules according to the invention, the polyisocyanate is no longer the main material, but only serves as a cross-linking agent for the amino acid and the above-mentioned other components.

[0388] Thus, the method according to the invention allows to replace part of the polyisocyanate with biodegradable wall materials such as protective colloids, amino acids, hydroxyl donors and release agents, thereby reducing the proportion of polyisocyanate without causing loss or loss of microcapsule functionality, such as olfactory properties and positive secondary properties such as high stability (i.e., the ability to retain active substances). Thus, the method according to the invention can prepare microcapsules that have both outstanding functionality and are easily biodegradable.

[0389] Surprisingly, it was found that according to the process of the invention it is possible to prepare microcapsules with a reduced amount of polyisocyanate by up to 60%, without causing a loss or loss of stability of the microcapsules obtained, as shown in the following examples. Thus, it is possible to prepare microcapsules containing a reduced amount of starting material isocyanate and the same amount of active substance to be encapsulated.

[0390] In another aspect, the present invention relates to biodegradable polyurea / polyurethane microcapsules prepared according to the method of the present invention.

[0391] Biodegradable polyurea / polyurethane microcapsules are characterized in that they consist of or contain:

[0392] (i) a core comprising at least one hydrophobic active substance; and

[0393] (ii) a capsule shell comprising:

[0394] - the reaction product of the polymerization and / or crosslinking of at least one polyisocyanate having two or more isocyanate groups with at least one first amino acid or amino acid hydrochloride, further polymerization and / or crosslinking with at least one hydroxyl donor, and further polymerization and / or crosslinking with at least one second amino acid in the presence of at least one protective colloid; and

[0395] - At least one release agent.

[0396] The alternating polymerization and / or crosslinking of polyisocyanate units with amino or hydroxyl functional groups leads to a stable capsule wall consisting of an alternatingly defined, dense and therefore stable crosslinking matrix or crosslinking units based on polyurethane and polyurea.

[0397] In a preferred embodiment, the capsule shell of the biodegradable polyurea / polyurethane microcapsule according to the present invention comprises or consists of:

[0398] (a) a first crosslinking matrix or first crosslinking unit consisting of 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;

[0399] (β) a second crosslinking matrix or second crosslinking unit consisting of crosslinks of at least one polyisocyanate having two or more polyisocyanate groups and at least one hydroxyl donor;

[0400] (γ) a third cross-linking matrix or third cross-linking unit consisting of cross-links of at least one polyisocyanate having two or more polyisocyanate groups and at least one second amino acid; and

[0401] (δ) at least one release agent; and

[0402] (ε) Optionally, other crosslinking matrices or crosslinking units based on polyester.

[0403] The first cross-linked matrix or cross-linked unit of the capsule shell of the microcapsule according to the present invention is a network based on polyurea. The second cross-linked matrix or cross-linked unit is a network based on polyurethane, and the third cross-linked matrix or cross-linked unit is another network based on polyurea. If necessary, the fourth cross-linked matrix or cross-linked unit is another network based on polyester. The composition of the cross-linked matrix or cross-linked unit of polyurea and / or polyurethane and / or polyester depends on the polyisocyanate and cross-linking agent used, i.e., protective colloid, first amino acid, hydroxyl donor and second amino acid.

[0404] In addition to the formation of the above-mentioned polyurethanes and the formation of polyureas, due to the reactivity of the polyisocyanates, by-products such as ureas, allophanates, biuret, uretdione, carbodiimide and uretonimine etc. 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.

[0405] By building the capsule wall based on multiple individual, defined and alternating crosslinking matrices or crosslinking units, particularly stable microcapsules with excellent sensory properties can be prepared while significantly reducing the shell composition. Finally, the incorporation of release agents further enhances the stability of the capsule shell.

[0406] Surprisingly, polyurea / polyurethane fragrance capsules made according to the process of the present invention have higher stability and reduced inadvertent leakage of fragrance oil, as shown in the examples below. This can be attributed, among other things, to more efficient encapsulation of the fragrance.

[0407] Surprisingly, it has been found that the microcapsules prepared according to the process of the present invention have at least 1.5 times greater stability, preferably at least 2 times greater stability, than prior art polyurea / polyurethane microcapsules, as shown in the following examples.

[0408] The microcapsules according to the invention also have a content of free hydrophobic active substances of 0.5% by weight or less, preferably a content of ≤0.3% by weight or less, even more preferably a content of ≤0.2% by weight.

[0409] Furthermore, the polyurea / polyurethane microcapsules according to the invention also show a clear improvement in the organoleptic properties (fragrance release) compared to the capsules of the prior art, which can be attributed to the stable active substance encapsulation and the associated low active substance loss. Figure 5 As shown in Figure 1, the microcapsules according to the present invention show significantly stronger sensory intensity when the capsules are opened by mechanical friction or pressure to release the fragrance. Compared with the capsules of the prior art, the polyurea / polyurethane microcapsules according to the present invention have a significant improvement in sensory performance (fragrance release), which is at least 1.5 times, preferably at least 1.75 times, and even more preferably at least 2 times.

[0410] As shown in the examples, as the degree of crosslinking increases, ie as the polyisocyanate content increases, the stability of the microcapsules also increases, but at the same time the biodegradability of the capsule shell also decreases. Figure 6 In general, the stability, performance and biodegradability of microcapsules are related to the degree of crosslinking. For example, for very stable microcapsules, the number of microcapsules that rupture and release active substances due to friction, pressure, etc. is reduced, and their performance (such as sensory performance) is lower.

[0411] As shown in the following examples, the polyurea / polyurethane microcapsules according to the present invention have a polyisocyanate content reduced by up to 60% compared to the polyurea / polyurethane microcapsules of the prior art, without any loss or penalty in terms of stability or the loading capacity of the microcapsules for the active substance to be encapsulated. Compared with the microcapsules of the prior art, the isocyanate is no longer the main material of the capsule shell or capsule wall, but only serves as a crosslinker for the amino acids and other main components of the capsule shell (such as protective colloids and hydroxyl donors). The absolute polyisocyanate content of the microcapsules described herein is only 1 / 60 of the entire capsule containing the active substance. Assuming that the raw materials are quantitatively reacted, it can be considered that out of 100% of the wall material, exactly 1 / 5 of the wall material is composed of polyisocyanate, which can only be considered as a crosslinker due to its very low content.

[0412] Due to the lower polyisocyanate content in the capsule shell or capsule wall on the one hand and the use of a release agent on the other hand, the microcapsules according to the invention are more biodegradable than capsules of the prior art. As shown in the following examples, the microcapsules according to the invention prepared using a release agent have significantly better biodegradability.

[0413] Biodegradability refers to the ability of organic matter to be degraded into water, carbon dioxide (CO) and water within a specified period of time in the presence of microorganisms or fungi under specified conditions of temperature, oxygen and humidity. 2 ) and biomass capacity.

[0414] According to OECD 301F, microcapsules are considered to be immediately biodegradable if more than 60% of the wall material is degraded after 28 days.

[0415] According to OECD 301F, the biodegradability of the microcapsules of the present invention after 28 days is ≥20%, preferably ≥50%, even more preferably ≥70%, most preferably ≥90%.

[0416] The combination of the starting components on the one hand and the sequence of crosslinking on the other hand make it possible for the microcapsules according to the invention to have sufficient stability (mechanical as well as diffusion stability in use) and high organoleptic properties while having outstanding biodegradability. Thus, the currently valid correlation between organoleptic properties, high crosslinking and biodegradability can be broken.

[0417] Furthermore, the microcapsule of the present invention is a universal capsule which can be used to encapsulate a wide range of aromas or flavors, even aromas or flavors having aldehyde, carboxylic acid or ester functions, according to the present state, and thus there is no limitation on the specific active substance.

[0418] 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 or paper printing coatings, etc.

[0419] Therefore, in another aspect, the present invention relates to the use of the biodegradable polyurea / polyurethane microcapsules according to the present invention or the dispersion of the polyurea / polyurethane microcapsules according to the present invention (microcapsule slurry) for the manufacture of household products, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance lotions or fragrance enhancers in liquid or solid form, cosmetics, personal care products, agricultural products, pharmaceutical products or paper printing coatings, etc.

[0420] Finally, the present invention relates to 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., which include biodegradable polyurea / polyurethane microcapsules according to the present invention or dispersions of polyurea / polyurethane microcapsules according to the present invention.

[0421] Example

[0422] The biodegradable polyurea / polyurethane microcapsules according to the present invention and their advantageous properties will be described in more detail by means of the following examples.

[0423] Example 1 - Wall Material Comparison

[0424] Table 1:

[0425]

[0426] *) All content data refer to complete microcapsules including oil

[0427] The microcapsules according to the present invention have significantly lower polyisocyanate content, which can be reduced by up to 60%. Compared with the microcapsules of the prior art, isocyanate is no longer the main material, but only serves as a crosslinking agent for amino acids and other components of the capsule material.

[0428] Example 2 - Capsule Stability

[0429] The following stability data refer to tests performed at 40°C using commercially available formulations (eg fragrance boosters or fabric softeners).

[0430] In the examples below, capsules whose capsule wall consists exclusively of a polyurea network are selected as prior art capsules. In the preparation of such capsules, generally no catalyst is used and the synthesis is carried out at a pH of 9. Polyvinyl alcohol is used as protective colloid.

[0431] The slurry was placed in isopropanol for 30 seconds to determine free oil. The oil content was then determined by SPME and then GC / MS.

[0432] Example 1 - Capsule stability with and without optimized pH

[0433] The properties of the free oil are determined by varying the pH. The microcapsules according to the invention are prepared by using an isocyanate mixture consisting of 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 as the hydroxyl donor and arginine as the second amino acid. DABCO is used as a catalyst and modified starch as a protective colloid. The starch used is in the form of a succinate. Beeswax is used as the wax. TomCap is used as the phase to be encapsulated. The emulsion or dispersion has a non-optimized pH of 8.5 at the beginning of the respective reaction, and the emulsion or dispersion has an optimized pH of 5.5 at the beginning of the respective reaction.

[0434] Table 2:

[0435]

[0436] It is clear that at slightly acidic pH values, the stability of the microcapsules is significantly improved. The capsules are considered stable when the free oil content is <1%. The lower the free oil content, the more stable the capsules.

[0437] Example 2 – Capsule stability as a function of pH

[0438] The properties of the free oil were determined by varying the pH. The microcapsules according to the invention were prepared by using an isocyanate mixture consisting of hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 75:25. Furthermore, lysine*HCl was used as the first amino acid, glycerol as the hydroxyl donor and histidine as the second amino acid. DABCO was used as a catalyst and modified starch as a protective colloid. The starch used was in the form of a succinate. Beeswax was used as the wax. TomCap was used as the phase to be encapsulated.

[0439] Table 3:

[0440]

[0441]

[0442] In the method according to the present invention, in order to prepare stable microcapsules, the optimum pH value of the emulsion or dispersion at the beginning of the respective reaction is in the range of 4 to 7.

[0443] Example 3 - Capsule stability as a function of polyisocyanate composition (comparison of a single polyisocyanate and a combination of two different polyisocyanates)

[0444] The microcapsules of the present invention are prepared using different single polyisocyanates or a combination of two different polyisocyanates, guanidine carbonate, polyvinyl alcohol as a protective colloid, and TomCap as a fragrance oil:

[0445] Table 4:

[0446]

[0447] The use of a combination of two different isocyanates results in microcapsules with a stability that exceeds that of a single isocyanate system. It is therefore preferred to use a mixture consisting of two different isocyanates.

[0448] Example 4 - Capsule stability as a function of polyisocyanate composition (comparison of aliphatic-aliphatic polyisocyanate mixtures and aliphatic-aromatic polyisocyanate mixtures)

[0449] The microcapsules of the present invention are prepared using an aliphatic-aliphatic polyisocyanate mixture and an aliphatic-aromatic polyisocyanate mixture as follows:

[0450] Aliphatic-aliphatic polyisocyanate mixture: pentamethylene diisocyanate and hexamethylene diisocyanate in a 50:50 ratio.

[0451] Aliphatic-aromatic polyisocyanate mixture: hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate in a ratio of 75:25.

[0452] In addition, lysine*HCl was used as the first amino acid, glycerol as the hydroxyl donor, and arginine as the second amino acid. DABCO was used as a catalyst, and modified starch was used as a protective colloid. TomCap was used as the phase to be encapsulated. Beeswax was used as the wax. The starch used was in the form of succinate.

[0453] Table 5:

[0454] Isocyanate mixture Free oil / % Aliphatic-Aliphatic 0.49 Aliphatic-Aromatic 0.09

[0455] The free oil in both samples was well below 1%, so both capsules are considered stable.The microcapsules made from the aliphatic-aliphatic polyisocyanate mixture are as stable as the microcapsules made from the aliphatic-aromatic polyisocyanate mixture.

[0456] Example 5 - Capsule stability with and without other catalysts

[0457] 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 75:25. In addition, lysine*HCl is used as the first amino acid, glycerol is used as the hydroxyl donor, and histidine is used as the second amino acid. DABCO is used as a catalyst and modified starch is used as a protective colloid. The starch used is in the form of succinate. Beeswax is used as the wax. TomCap is used as the phase to be encapsulated. In addition, an additional catalyst is used in the preparation process.

[0458] Table 6:

[0459]

[0460] The stability of the microcapsules prepared using the additional catalyst after 4 weeks was twice that of the microcapsules prepared without the additional catalyst.

[0461] Example 6 - Capsule Stability with and without First Catalyst

[0462] The microcapsules according to the invention are prepared by using an isocyanate mixture consisting of 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 as the hydroxyl donor, and histidine as the second amino acid. p-Toluenesulfonic acid is used as an additional or second catalyst, and modified starch is used as a protective colloid. The starch used is in the form of a succinate. Beeswax is used as the wax. TomCap is used as the phase to be encapsulated.

[0463] Table 7:

[0464]

[0465] The microcapsules prepared using the first catalyst are much more stable, so it is necessary to use a polyurethane catalyst such as DABCO.

[0466] Example 3 - Relationship between biodegradability and free oil and the amount of crosslinker (isocyanate)

[0467] Free oil content was determined as described above.

[0468] Biodegradability was determined according to OECD 301F as follows: The degradability of the wall material in non-preconditioned culture medium was measured by manometric respiration (oxygen consumption).

[0469] Table 7:

[0470]

[0471] As the amount of polyisocyanate (crosslinker) used decreases, the biodegradability increases. In this case, surprisingly there is a minimal increase in free oil, which allows the capsules to be considered stable.

[0472] Example 4 - Comparison of biodegradability with and without release agent

[0473] Table 8:

[0474]

[0475]

[0476] *) All content data refer to complete microcapsules including oil

[0477] *) Content data related to capsules including oil

[0478] The capsules according to the invention showed a biodegradability of 96%, so that the wall material can be considered to be immediately biodegradable.

[0479] Example 6 - Comparison of biodegradability with sodium sulfate and toxicity controls

[0480] The biodegradability of the wall material of the microcapsules according to Example 5 of the invention was tested according to OECD 301 F. For this purpose, sodium benzoate was used as a process control and a mixture of microcapsules according to the invention and sodium benzoate as a toxicity control.

[0481] Test replicates 1 and 2 = capsules according to the invention

[0482] Method Control Replicate 1 and 2 = Sodium Sulfate

[0483] Toxicity control = Combination of capsules according to the invention and sodium sulfate to control toxicological effects

[0484] Test results such as Figure 4 shown.

[0485] The capsules according to the invention showed an average biodegradability of 96% for both samples, so the wall material can be considered to be immediately biodegradable. The toxicity control also showed degradability, thus demonstrating that the wall material of the capsules according to the invention is not persistent.

[0486] Example 7 - Comparison of biodegradability with and without wax

[0487] 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 75:25. In addition, lysine*HCl is used as the first amino acid, glycerol as the hydroxyl donor, and arginine as the second amino acid. DABCO is used as a catalyst and modified starch as a protective colloid. The wall material is then separated by using a centrifuge, a rotary evaporator and a vacuum drying oven. Ethyl acetate is used as the phase to be encapsulated. The waxes used are given in the following table. The starch used is in the form of succinate.

[0488] Table 9:

[0489] wax Biodegradability after 28 days according to OECD 301F / % No wax 12 beeswax 96 Sunflower wax 72

[0490] Both capsules are considered biodegradable according to OECD 301F due to the use of wax. Surprisingly, the use of wax disproportionately increases biodegradability despite the small amount of wax used.

[0491] Example 8 - Sensory Test

[0492] For the sensory evaluation, the microcapsules according to the invention were compared with microcapsules of the prior art, ie microcapsules based on a polyurea / polyurethane structure without the use of a release agent and at a pH of 9.

[0493] 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 the hydroxyl donor, and arginine is used as the second amino acid. DABCO is used as a catalyst, modified starch is used as a protective colloid; beeswax is added as a release agent. The pH value of the emulsion or dispersion at the beginning of the respective reaction is adjusted to pH 5.5.

[0494] 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.

[0495] Twelve testers rated the intensity of the fragrance 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 described the odor of the untreated cloth. The second step described the odor of the cloth after it had been gently kneaded; for this purpose, the cloth was subjected to slight mechanical pressure by moving it back and forth several times between the hands, causing the capsules to break. The third step described the odor of the cloth after it had been rubbed vigorously, thus breaking the capsules.

[0496] like Figure 5 As shown, the microcapsules according to the invention have significantly better properties. This can be attributed to the targeted modification of the system: Due to the pH-optimized crosslinking and the use of release agents, a stable capsule wall structure is constructed, which makes the capsules more odor-resistant but still biodegradable.

Claims

1. A method for preparing biodegradable polyurea / polyurethane microcapsules, the method comprising: The following steps are involved: (a) performing a first polymerization and / or cross-linking step, comprising: (a1) providing an inner non-aqueous phase comprising at least one polyisocyanate having two or more isocyanate groups and at least one lipophilic active substance to be encapsulated; (a2) providing an external aqueous phase comprising at least one protective colloid and optionally an emulsifier, and adjusting the pH of the aqueous phase to a value of 1 to 5; (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 first amino acid or amino acid hydrochloride and a catalyst, and adjusting the pH of the emulsion or dispersion to 4 to 8; (b) carrying out a second polymerization and / or crosslinking step by adding at least one hydroxyl donor; (c) adding at least one second amino acid and adjusting the pH of the emulsion or dispersion to 4 to 8, and performing a third polymerization and / or crosslinking step at a temperature of at least 60° C. to obtain a microcapsule dispersion; (d) optionally adding further catalyst and adjusting the pH of the emulsion or dispersion to between 4 and 7; (e) curing the microcapsule dispersion obtained from step (c) or (d) at a temperature of at least 60° C. for at least 60 minutes; (f) adding at least one release agent and incorporating the release agent into the microcapsule shell; (g) post-curing the microcapsules obtained in step (f); and optionally: (h) separating the microcapsules from the microcapsule dispersion, 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, alicyclic, hydrogenated aromatic, aromatic or heterocyclic polyisocyanates, substitution products thereof and mixtures thereof.

3. The method of claim 2, wherein the at least one polyisocyanate comprises two aliphatic polyisocyanates or one aliphatic and one aromatic polyisocyanate.

4. The method of claim 2, wherein the at least one polyisocyanate comprises polyisocyanates having varying chain lengths in alternating monomeric, oligomeric or polymeric structures.

5. The method according to any one of the preceding claims 1 to 4, wherein the at least one lipophilic active substance to be encapsulated is selected from the group consisting of fragrances, flavoring agents, cooling agents, TRPV1 and TRPV3 modulators, substances that cause a pungent taste or a sensation of heat or heat on the skin or mucous membranes, or substances that cause a tingling sensation in the mouth or throat, or active substances with irritating or pungency or astringent effects, food additives, cosmetic active substances, pharmaceutical active substances, dyes, dye precursors, fluorescent dyes, agrochemicals, optical brighteners, solvents, waxes, silicone oils, lubricants, paper printing coatings, and mixtures of two or more of the above active substances, wherein the substance causing a pungent taste or heat or hot sensation on the skin or mucous membrane 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, golden button extract, Japanese pepper extract, kaempferia extract, galangal extract, water pepper extract, capsaicinoids; gingerols; shogaols; gingerdione; gingerols; dehydrogingerdiones; piperine; piperine derivatives; ethyl 2-(4-hydroxy-3-methoxy-phenyl)acetate and 3-phenylpropyl-2-(4-hydroxy-3-methoxy-phenyl)acetate and mixtures thereof; The substance causing a tingling sensation in the mouth or throat is selected from the group consisting of: 2E,4E-decadienoic acid-N-isobutylamide; 2E,4Z-decadienoic acid-N-isobutylamide; 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-piperidin; 2E-decenoic acid-N-isobutylamide; 3E-decenoic acid-N-isobutylamide; 3E-nonenoic acid-N-isobutylamide; 2E,6Z,8E-decatrienoic acid-N-isobutylamide; 2E,6Z,8E-decatrienoic acid-N-([2S]-2-methylbutyl)amide; 2E,6Z,8E-decatrienoic acid-N-([2R]-2-methylbutyl)amide; 2E-decene-4-acid-N-isobutylamide; 2Z-decene-4-ynoic acid-N-isobutylamide; 2E,6Z,8E,10E- 2E,6Z,8E,10E-docotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide; 2E,6E,8E,10E-docotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide; 2E,4E,8Z,10E,12E-tetradecanoic acid-N-(2-hydroxy-2-methylpropyl)amide; 2E,4E,8E,10E,12E-tetradecanoic acid-N-(2-hydroxy-2-methylpropyl)amide; 2E,4E,8Z,10E,12E-tetradecanoic acid-N-(2-hydroxy-2-methylpropyl)amide; Acid-N-(2-methyl-2-propenyl)amide; 2E,4E,8Z,10E,12E-tetradecanoic acid-N-(2-methylpropyl)amide; 2E,4E,8Z,11Z-tetradecotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide; 2E,4E,8Z,11E-tetradecotetraenoic acid-N-(2-hydroxy-2-methylpropyl)amide; 2E,4E,8Z-tetradecatetrienoic acid-N-(2-hydroxy-2-methylpropyl)amide and 2E,4E-tetradecadienoic acid-N-(2-hydroxy-2-methylpropyl)amide and mixtures thereof; wherein the active substance having irritation or pungency is selected from the group consisting of aromatic isothiocyanates, allyl isothiocyanates, cyclopropyl isothiocyanates, butyl isothiocyanates, 3-methylthiopropyl isothiocyanate and mixtures thereof; The active substance having astringent effect is selected from the group consisting of catechins, their oligomers and C- and O-glycosides thereof; dihydroflavonoids and their C- and O-glycosides, flavonols and their C- and O-glycosides and mixtures thereof.

6. The method of claim 5, wherein the aromatic isothiocyanate is selected from the group consisting of phenethyl isothiocyanate, 4-hydroxybenzyl isothiocyanate, 4-methoxybenzyl isothiocyanate, and mixtures thereof.

7. The method of claim 5, wherein the agrochemical is a pesticide.

8. The method of claim 5, wherein the agrochemical is a biocide.

9. The method of claim 5, wherein the agricultural chemical is a pesticide.

10. The method according to claim 5, wherein the agricultural chemical is an insect repellent-type substance.

11. The method according to any one of the preceding claims 1 to 4, It is characterized in that The at least one lipophilic active substance to be encapsulated is selected from the group consisting of fragrances or flavorings having an aldehyde, carboxylic acid or ester function.

12. The method according to any one of the preceding claims 1 to 4, It is characterized in that The 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 compounds.

13. The method according to claim 12, It is characterized in that The polyol is selected from diols, triols, polyvinyl alcohol and its derivatives, polyphenols, glucose and polysaccharides.

14. The method according to claim 13, It is characterized in that The diol is selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, isomeric butylene glycols, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol and 1,2-dodecanediol.

15. The method according to claim 13, It is characterized in that The triol is selected from glycerol and ethoxylation and propoxylation products thereof; and trimethylolpropane and ethoxylation and propoxylation products thereof.

16. The method according to claim 13, It is characterized in that The polyvinyl alcohol derivative is ammonium or sulfonate functionalized polyvinyl alcohol.

17. The method according to claim 13, It is characterized in that The polyphenol is 1,3,5-trihydroxybenzene.

18. The method according to claim 13, It is characterized in that The polysaccharide is selected from starch or chemically, mechanically and / or enzymatically modified starch and cellulose derivatives.

19. The method according to claim 18, It is characterized in that The cellulose derivative is selected from hydroxyethyl cellulose and carboxymethyl cellulose.

20. The method according to claim 19, It is characterized in that The hydroxyethyl cellulose is quaternized hydroxyethyl cellulose.

21. The method according to claim 12, It is characterized in that The animal and plant polymers are selected from gum arabic, protein, gelatin, mastic, shellac, lignin, chitosan and saponin.

22. The method according to any one of the preceding claims 1 to 4, It is characterized in that The protective colloid is used in combination with starch.

23. The method according to any one of the preceding claims 1 to 4, It is characterized in that At least one first 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.

24. A process according to any one of claims 1 to 4, wherein the catalyst added in step (a4) is selected from the group consisting of: diazabicyclo[2.2.2]octane, bismuth catalysts and tin catalysts and mixtures thereof; and the additional catalyst optionally added in step (d) is selected from the group consisting of: p-toluenesulfonic acid, sulfuric acid, germanium oxide or an enzyme catalyst.

25. The method of claim 24, wherein the enzyme catalyst is Candida antarctica lipase B.

26. The method according to any one of the preceding claims 1 to 4, wherein the hydroxyl donor is a polyol having two or more hydroxyl groups.

27. The method according to the preceding claim 26, wherein the polyol having two or more hydroxyl groups is selected from glycerol, propylene glycol, 1,3,5-trihydroxybenzene, starch, modified starch, cellulose derivatives, gum arabic and mixtures thereof.

28. The method according to claim 27, wherein the cellulose derivative is selected from hydroxyethyl cellulose and carboxymethyl cellulose.

29. The method according to claim 28, wherein the hydroxyethyl cellulose is quaternized hydroxyethyl cellulose.

30. The method according to any one of the preceding claims 1 to 4, It is characterized in that At least one second amino acid is selected from the group consisting of arginine, histidine, aspartic acid, lysine, glycine, alanine, proline, cysteine, glutamine, leucine, serine, tryptophan, valine, threonine, ornithine, and mixtures thereof.

31. The method according to any one of the preceding claims 1 to 4, It is characterized in that At least one release agent is selected from the group consisting of: - long-chain, aliphatic, linear or branched, saturated or unsaturated carboxylic acids having 12 to 30 carbon atoms; - long-chain, aliphatic, straight-chain or branched, saturated or unsaturated primary alcohols having 12 to 30 carbon atoms; - esters of long-chain aliphatic saturated carboxylic acids having 12 to 30 carbon atoms and long-chain aliphatic primary alcohols having 12 to 30 carbon atoms; and -Animal and vegetable waxes; and mixtures of the above release agents.

32. The method according to claim 31, wherein the long-chain, aliphatic, straight or branched, saturated or unsaturated carboxylic acid having 12 to 30 carbon atoms is selected from lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, heneicosanoic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid and melissic acid; myristoleic acid, palmitoleic acid, heptadecenic acid, octadecenoic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, gondoic acid, cetoleic acid, erucic acid, nervonic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, calendulaic acid, punicic acid, α-eleostearic acid, β-eleostearic acid, octadecatetraenoic acid, arachidonic acid, eicosapentaenoic acid, docosatetraenoic acid, docosapentaenoic acid, docosahexaenoic acid and tetracoshexaenoic acid; and phytanic acid.

33. The method according to claim 31, wherein the long-chain, aliphatic, straight or branched, saturated or unsaturated primary alcohol having 12 to 30 carbon atoms is selected from lauryl alcohol, myristyl alcohol, palmityl alcohol, heptadecanol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, wax alcohol, montanyl alcohol and myricyl alcohol; palmitoleyl alcohol, oleyl alcohol, elaidic alcohol, linoleyl alcohol, and gamma-linolenic alcohol.

34. The method according to claim 31, wherein the esters of long-chain aliphatic saturated carboxylic acids having 12 to 30 carbon atoms and long-chain aliphatic primary alcohols having 12 to 30 carbon atoms are selected from lauryl palmitate, myristyl palmitate, cetyl arachidate and stearyl behenate.

35. The method according to claim 31, wherein the animal and plant waxes are selected from wool wax, China wax, beeswax, sunflower seed wax, rice bran wax, carnauba wax, pinoa wax, rapeseed wax, soy wax, candelilla wax, jojoba oil, cork wax, guarana wax, cotton wax, flax wax, peat wax, rose wax, jasmine wax, pumpkin pita wax, myrtle wax, fig wax, and berry wax.

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

37. The biodegradable polyurea / polyurethane microcapsule according to claim 36, include: (i) a core comprising at least one hydrophobic agent; and (ii) a capsule shell comprising: - a reaction product of the polymerization and / or crosslinking of at least one polyisocyanate having two or more isocyanate groups with at least one first amino acid or amino acid hydrochloride, further polymerization and / or crosslinking with at least one hydroxyl donor, and further polymerization and / or crosslinking with at least one second amino acid in the presence of a protective colloid; and - At least one release agent.

38. The biodegradable polyurea / polyurethane microcapsule according to claim 37, It is characterized in that The capsule shell comprises: (a) a first crosslinking matrix or first crosslinking unit consisting of 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; (β) a second crosslinking matrix or second crosslinking unit consisting of crosslinks of at least one polyisocyanate having two or more polyisocyanate groups and at least one hydroxyl donor; (γ) a third cross-linking matrix or third cross-linking unit consisting of cross-links of at least one polyisocyanate having two or more polyisocyanate groups and at least one second amino acid; and (δ) at least one release agent; and (ε) Optionally, other polyester-based cross-linking matrices or cross-linking units.

39. The biodegradable polyurea / polyurethane microcapsules according to any one of claims 36 to 38, It is characterized in that It has a biodegradability of ≥20% according to OECD 301F after 28 days and / or a content of free hydrophobic active substances of ≤0.3% by weight.

40. Use of the biodegradable polyurea / polyurethane microcapsules according to any one of claims 36 to 39 or the biodegradable polyurea / polyurethane microcapsule dispersion according to claim 36 for manufacturing household products, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, liquid or solid fragrance lotions or fragrance enhancers, cosmetics, personal care products, fragrance compositions, agricultural products, pharmaceutical products or paper printing coatings.

41. Household products, textile care products, detergents, fabric softeners, cleaning agents, fragrance boosters, fragrance lotions and fragrance enhancers, cosmetics, personal care products, fragrance compositions, agricultural products, pharmaceutical products or paper printing coatings, comprising the biodegradable polyurea / polyurethane microcapsules according to any one of claims 36 to 39 or the biodegradable polyurea / polyurethane microcapsule dispersion according to claim 36.

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