Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/84—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds obtained by reactions otherwise than those involving only carbon-carbon unsaturated bonds
  • A61K8/87—Polyurethanes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/06—Making microcapsules or microballoons by phase separation
  • B01J13/14—Polymerisation; cross-linking
  • B01J13/16—Interfacial polymerisation
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
  • A01N25/26—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests in coated particulate form
  • A01N25/28—Microcapsules or nanocapsules
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23P—SHAPING OR WORKING OF FOODSTUFFS, NOT FULLY COVERED BY A SINGLE OTHER SUBCLASS
  • A23P10/00—Shaping or working of foodstuffs characterised by the products
  • A23P10/30—Encapsulation of particles, e.g. foodstuff additives
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/02—Cosmetics or similar toiletry preparations characterised by special physical form
  • A61K8/04—Dispersions; Emulsions
  • A61K8/06—Emulsions
  • A61K8/062—Oil-in-water emulsions
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/02—Cosmetics or similar toiletry preparations characterised by special physical form
  • A61K8/11—Encapsulated compositions
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/30—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
  • A61K8/33—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing oxygen
  • A61K8/34—Alcohols
  • A61K8/345—Alcohols containing more than one hydroxy group
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/30—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds
  • A61K8/40—Cosmetics or similar toiletry preparations characterised by the composition containing organic compounds containing nitrogen
  • A61K8/41—Amines
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/73—Polysaccharides
  • A61K8/732—Starch; Amylose; Amylopectin; Derivatives thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K8/00—Cosmetics or similar toiletry preparations
  • A61K8/18—Cosmetics or similar toiletry preparations characterised by the composition
  • A61K8/72—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds
  • A61K8/84—Cosmetics or similar toiletry preparations characterised by the composition containing organic macromolecular compounds obtained by reactions otherwise than those involving only carbon-carbon unsaturated bonds
  • A61K8/88—Polyamides
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61Q—SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
  • A61Q19/00—Preparations for care of the skin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/02—Making microcapsules or microballoons
  • B01J13/20—After-treatment of capsule walls, e.g. hardening
  • B01J13/206—Hardening; drying
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/0039—Coated compositions or coated components in the compositions, (micro)capsules
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/50—Perfumes
  • C11D3/502—Protected perfumes
  • C11D3/505—Protected perfumes encapsulated or adsorbed on a carrier, e.g. zeolite or clay
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K2800/00—Properties of cosmetic compositions or active ingredients thereof or formulation aids used therein and process related aspects
  • A61K2800/40—Chemical, physico-chemical or functional or structural properties of particular ingredients
  • A61K2800/56—Compounds, absorbed onto or entrapped into a solid carrier, e.g. encapsulated perfumes, inclusion compounds, sustained release forms
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/48—Preparations in capsules, e.g. of gelatin, of chocolate
  • A61K9/50—Microcapsules having a gas, liquid or semi-solid filling; Solid microparticles or pellets surrounded by a distinct coating layer, e.g. coated microspheres, coated drug crystals
  • A61K9/5005—Wall or coating material
  • A61K9/5021—Organic macromolecular compounds
  • A61K9/5031—Organic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, poly(lactide-co-glycolide)
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/48—Preparations in capsules, e.g. of gelatin, of chocolate
  • A61K9/50—Microcapsules having a gas, liquid or semi-solid filling; Solid microparticles or pellets surrounded by a distinct coating layer, e.g. coated microspheres, coated drug crystals
  • A61K9/5089—Processes

Definitions

• the present invention relates to a process for the production of multilayer microcapsules, preferably multilayer fragrance or fragrance capsules, which have an improved stability and fragrance or fragrance release compared to capsules of the prior art.
• the present invention relates to multilayer microcapsules, comprising at least one hydrophobic fragrance or fragrance, which can be obtained by the method according to the invention.
• the invention described herein relates to multilayer microcapsules, comprising a core comprising at least one hydrophobic fragrance or fragrance, and a capsule shell.
• the present invention relates to the use of the multilayer microcapsules and suspensions from the multilayer microcapsules as a component of detergents, fabric softeners, cleaning agents, scent boosters (fragrance enhancers) in liquid or solid form, cosmetics, personal care products, agricultural products or pharmaceutical products.
• the aim of encapsulation is, among other things, the targeted release of the active ingredients, the conversion of liquids into a manageable powder form, the delay of losses of volatile components (eg with flavorings), the prevention of premature chemical reactions with other mixture components or better handling before or during processing.
• encapsulated active ingredients such as fragrances or rich substances, can be encapsulated and incorporated into various application formulations.
• microcapsules can then be released in various ways and is based in particular on one of the mechanisms described below: mechanical destruction of the capsule by
• fragrances are perfumed with fragrances or fragrance mixtures.
• the fragrances can be added to the formulation in encapsulated form. In this way, the desired smell impression can be guaranteed.
• the document EP 2111214 B1 describes microcapsules with a fragrance core and an aminoplast polymer encapsulation. In addition to the high tightness of the descriptive capsule shell, it is also very resistant to reactive chemicals. The polycondensation of amine-formaldehyde precondensate and the water-insoluble, hydrophobic active ingredient, such as a perfume oil, is initiated by a change in pH.
• microcapsules made from (a) an Epoxypropyltrialkylammommiumsalz and also an alkyl sulfosuccinate, which has alkyl groups with 6 to 16 carbon atoms, or an alkyl sulfosuccinamate, the carboxamide group is substituted with an alkyl group with 8 to 20 carbon atoms, and one water-miscible solvents as component b) described.
• the document EP 3238816 A1 discloses a method for producing microcapsules, in particular aminoplast microcapsules, from a first aqueous preparation containing at least one prepolymer and a second non-aqueous preparation containing the active ingredient to be encapsulated, so that the mean diameter of the capsules is reduced in size and unified. Furthermore, the method described therein leads to a significant reduction in the microcapsule particle size and thus to a stabilization of the emulsion.
• WO 2017/148504 A1 describes a method for producing fragrance capsules which have improved storage stability in an aqueous-surfactant environment, the fragrance composition, which has an acid number of at most 5 mg KOH / g immediately before encapsulation natural coating materials or synthetic, anionic or cationic polymers or mixtures thereof is encapsulated.
• Microcapsules can also be made from other polymerizable materials such as acrylate monomers, polyureas or biopolymers.
• Isocyanate-based microcapsules are usually made from polyisocyanates and guanidinium carbonate in an alkaline environment.
• microcapsules of the prior art have the disadvantage that polymeric capsule wall or capsule shell material require a large proportion of polymer in order to ensure sufficient stability and not suffer too great a loss of active ingredient. Furthermore, such microcapsules often do not have any biodegradable properties. In addition, there is usually an inadequate release of active ingredients in the application.
• the present invention was based on the complex object of providing a method for producing microcapsules, which makes it possible to provide highly stable microcapsules with a low polymer content, which at the same time show an excellent release behavior of the encapsulated active ingredients and are as biodegradable as possible Have properties.
• this object can be achieved in that the targeted layered crosslinking at defined temperatures and targeted catalyzed mechanisms leads to stable multilayer microcapsules and thus an efficient encapsulation of active ingredients with subsequent targeted release of these active ingredients, for example by mechanical rubbing or by pressure.
• a first object of the present invention therefore relates to a method for producing multilayered microcapsules, preferably multilayered fragrance or fragrance capsules, which comprises the following steps in this order: a) Forming a first crosslinking layer by: a1) providing an internal one -aqueous phase comprising at least one isocyanate with two or more isocyanate groups and at least one active ingredient to be encapsulated; a2) providing an external aqueous phase comprising at least one protective colloid; a3) mixing the internal non-aqueous phase and the external aqueous phase to obtain an oil-in-water emulsion; b) formation of a second crosslinking layer by adding an amine which reacts at an acidic pH; c) formation of a third crosslinking layer by adding a hydroxyl group donor; d) formation of at least one fourth crosslinking layer by adding at least one amine which reacts at an alkaline pH value to obtain multilayer microcapsules; e) hardening of the multilayer microcapsules
• the invention described herein relates to multilayer microcapsules, comprising at least one hydrophobic fragrance or fragrance, which are produced by the method according to the invention.
• multilayer microcapsules comprising a core comprising at least one hydrophobic fragrance or fragrance, and a capsule shell, wherein the capsule shell from the inside outwards comprises or consists of:
• the present invention relates to the use of the multilayer microcapsule or suspension of the multilayer microcapsules according to the invention for the production of detergents, fabric softeners, cleaning agents, scent boosters (fragrance enhancers) in liquid or solid form, cosmetics, personal care products, Agricultural products or pharmaceutical products.
• the combination of targeted, defined and layered deposition of crosslinked capsule wall materials at defined temperatures and targeted catalyzed mechanisms leads to stable multilayer microcapsules and thus an efficient encapsulation of active ingredients with subsequent targeted release of these active ingredients , for example by mechanical rubbing or pressure, can be guaranteed.
• the multilayer microcapsules described herein show good biocompatibility due to their bio-based and biodegradable building blocks such as amino acids and starch.
• At least one or “at least one” or “one or more” as used herein refers to 1 or more, for example 2, 3, 4, 5, 6, 7, 8, 9 or more .
• FIG. 1 is a light microscope image of the multilayer microcapsules according to the invention made from 100% longer-chain diisocyanate. An Olympus BX51 was used for the light microscope image. The bar shown corresponds to 50 pm.
• FIG. 2 is a light microscope image of the multilayer microcapsules according to the invention made from 100% shorter-chain diisocyanate. An Olympus BX51 was used for the light microscope image. The bar shown corresponds to 50 pm.
• FIG. 3 is a light microscope image of the multilayer microcapsules according to the invention produced from 50% longer-chain diisocyanate and 50% shorter-chain diisocyanate.
• An Olympus BX51 was used for the light microscope image. The bar shown corresponds to 50 pm.
• FIG. 4 is a light microscope image of the multilayer microcapsules according to the invention made from 80% longer-chain diisocyanate and 20% aromatic diisocyanate.
• An Olympus BX51 was used for the light microscope image. The bar shown corresponds to 50 pm.
• Figure 5 is a diagram showing the results of an IR spectroscopic analysis of microcapsules from the prior art, d. H. of microcapsules based on a pure network of polyurea structures, and of microcapsules according to the invention. The analysis was carried out using ATR infrared spectroscopy (Attenuated total reflection).
• FIG. 6 shows a diagram of the particle size distribution (d (0.5) value) of multilayer microcapsules according to the invention and microcapsules of the prior art based on a pure polyurea network.
• a MALVERN Mastersizer 3000 was used to determine the particle size distribution. The corresponding calculation is based on the Mie theory.
• FIG. 7 is a diagram showing the results of a sensory evaluation of microcapsules from the prior art, i. H. of microcapsules based on a pure network of polyurea structures, and of microcapsules according to the invention.
• the present invention relates to a method for producing multi-layer microcapsules, preferably a method for producing multi-layer fragrance or fragrance capsules, which comprises the following steps in this order or consists of the following steps: a) Formation of a first crosslinking layer by: a1) providing an internal non-aqueous phase comprising at least one isocyanate with two or more isocyanate groups and at least one active ingredient to be encapsulated; a2) providing an external aqueous phase comprising at least one protective colloid, preferably the protective colloid is a polysaccharide, particularly preferably starch; a3) mixing the internal non-aqueous phase and the external aqueous phase to obtain an oil-in-water emulsion; b) formation of a second crosslinking layer by adding an amine which reacts at an acidic pH; c) formation of a third crosslinking layer by adding a hydroxyl group donor; d) formation of at least one fourth crosslinking layer
• multilayer microcapsules are understood to mean microparticles which have a capsule shell or capsule wall and one or more active ingredients as core material in the interior of the capsule. These are preferably hydrophobic active ingredients.
• the terms “microcapsule” and “capsule” are used synonymously for the purposes of the present invention.
• the capsule shell or capsule wall is preferably made up of several layers, which preferably have different compositions.
• a particularly preferred embodiment of the capsule shell comprises at least one polyurethane-based and at least one polyurea-based (crosslinking) layer. Alternating layers comprising polyurethane and polyurea structures are particularly preferred.
• a first crosslinking layer is formed.
• an internal non-aqueous phase which comprises at least one isocyanate with two or more isocyanate groups and at least one active ingredient to be encapsulated.
• the at least one isocyanate which is used in the manufacturing process described herein has at least two isocyanate groups for the formation of polymeric networks and thus for the formation of the capsule shell or capsule wall by polymerization.
• Corresponding polymerizable isothiocyanates alone or in combination with isocyanates, can also be used for use in the process according to the invention.
• Particularly preferred are aliphatic, cycloaliphatic, hydroaromatic, aromatic or heterocyclic polyisocyanates or polyisothiocyanates, their substitution products and mixtures of the aforementioned monomeric or oligomeric compounds, aliphatic and / or aromatic compounds being preferred.
• diisocyanates are particularly preferred and are therefore primarily used in carrying out the present invention.
• the present invention relates to a process for the production of multilayer microcapsules, wherein the at least one isocyanate with two or more isocyanate groups is selected from the group of aliphatic isocyanates and / or aromatic isocyanates and the corresponding isothiocyanates .
• the aliphatic isocyanates used have five or more carbon atoms.
• the internal non-aqueous phase comprises mixtures of different polymerizable isocyanates and / or isothiocyanates which can form copolymers.
• Examples of the monomeric isocyanates and / or isothiocyanates which can be used according to the invention and which contain at least two isocyanate groups or isothiocyanate groups are:
• TDI Tolylene diisocyanate (isomeric mixture of 2,4- and 2,6-tolylene diisocyanate in a ratio of 80:20)
• HDI hexamethylene diisocyanate- (1, 6)
• IPDI IPDI
• Isophorone diisocyanate or DMDI diphenylmethane-4,4'-diisocyanate.
• monomeric isocyanate 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-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate), 4,4'-
• aromatic isocyanates e.g. B. toluene diisocyanates or 4,4'-diisocyanatodiphenylmetha are used.
• Polyisocyanates which can be represented by modification of the above-mentioned diisocyanates or mixtures thereof by known methods and z.
• B. uretdione, urethane, isocyanurate, biuret and / or allophanate groups can be used.
• the combination of at least two different (preferably aliphatic and / or aromatic) diisocyanates is even more preferred.
• the different (preferably aliphatic) diisocyanates also have different chain lengths.
• Primary versions include, in particular, mixtures of longer-chain and shorter-chain diisocyanates in any mixing ratio.
• the mixing ratio of longer-chain diisocyanates to shorter-chain diisocyanates is preferably in a range from 4: 1 to 1: 4 and particularly preferably from 2: 1 to 1: 2.
• Longer-chain diisocyanates in this context preferably have six or more carbon atoms, more preferably have however, they are six to twelve Carbon atoms and particularly preferably six to eight carbon atoms.
• Short-chain diisocyanates are to be understood as meaning diisocyanates with one to five carbon atoms and preferably diisocyanates with three to five carbon atoms.
• microcapsules could be produced, which were provided both from a mixture of linear and aromatic isocyanates and from a mixture of two different linear isocyanates.
• Such microcapsules particularly when used as odorant capsules, exhibit outstanding odor storage properties and, associated therewith, excellent odorant release, as is illustrated by the following exemplary embodiments.
• the combination of different polymerizable isocyanates therefore leads to particularly stable capsule shells or capsule walls, which in turn is reflected in better performance (fragrance release) of the capsules, for example in the area of fragrance or fragrance encapsulation. Accordingly, in principle, the combination of at least two different polymerizable (preferably aliphatic and / or aromatic) isocyanates is to be preferred in the present invention.
• FIGS. 1 to 4 the influence of the chain length of the isocyanates on the resulting microcapsules is shown.
• FIG. 1 shows the light microscopic image of microcapsules according to the invention produced exclusively from longer-chain diisocyanates, here the isocyanate flexamethylene diisocyanate
• FIG. 2 shows microcapsules based on shorter-chain diisocyanates such as the isocyanate pentamethylene diisocyanate.
• the microcapsules from FIG. 2 have a more homogeneous morphology, they are less stable.
• FIGs 3 and 4 microcapsules according to the invention are shown starting from mixed isocyanates:
• Figure 3 shows the morphology of microcapsules based on a mixture of 50% shorter-chain and 50% longer-chain aliphatic isocyanates (mixture of flexamethylene diisocyanate and pentamethylene diisocyanate in a ratio of 50:50 ) while
• FIG. 4 shows a corresponding mixture of 80% longer-chain diisocyanates and 20% of an aromatic diisocyanate (flexamethylene diisocyanate and 4,4'-methyldiphenylene diisocyanate in a ratio of 80:20).
• microcapsules made from mixed aliphatic and / or aromatic isocyanates, have better stabilities and are therefore primarily suitable for the process described herein and therefore for the production of the multilayer microcapsules according to the invention, which have excellent stabilities and active ingredient release properties, as in the following exemplary embodiments is illustrated.
• aliphatic isocyanates and / or isothiocyanates with chain lengths of one to twelve carbon atoms in the chain, preferably three to eight carbon atoms and particularly preferably four to seven carbon atoms for the production of multilayer microcapsules according to the present invention .
• Polymerizable aliphatic isocyanates are particularly preferred in this context because of their chemical relationship to bio-based systems. For example, both lysine and 1,5-diisocyanatopentane show the same degradation product, 1,5-diaminopentane, and are therefore particularly suitable for use in the production of bio-based and biodegradable microcapsules, taking environmental aspects into account.
• the present invention also relates to a method for producing multilayer microcapsules, comprising at least two aliphatic isocyanates with two or more isocyanate groups, in which the at least two isocyanates have different chain lengths.
• a process comprising at least two aliphatic isocyanates and / or isothiocyanates with two or more isocyanate / isothiocyanate groups, in which the at least two isocyanates / isothiocyanates have different chain lengths, is also preferred.
• At least one of the aliphatic isocyanates and / or isothiocyanates preferably has a chain length of five or more carbon atoms.
• mixtures of isocyanate and isothiocyanate compounds in the internal non-aqueous phase which have the properties mentioned above, are therefore also fundamentally conceivable.
• microcapsules described herein can be produced from aromatic isocyanates having two or more isocyanate groups.
• the present invention therefore relates to a process for the production of multilayer microcapsules, in which the isocyanate or isocyanates with two or more isocyanate groups is or are selected from the group of aromatic isocyanates.
• the proportion of the isocyanate component to the internal non-aqueous phase is preferably between 1:50 and 1:20, more preferably between 1:40 and 1:30.
• the internal non-aqueous phase can therefore contain, for example, 0.1 to 10.0% by weight and preferably 0.5 to 3.0% by weight isocyanate, based on the total weight of the internal non-aqueous phase.
• the isocyanate component Due to the low proportion of the isocyanate component, it is possible based on the present invention to produce multilayer microcapsules in which the absolute isocyanate proportion is only 1/50 of the total capsule which comprises the active ingredient (s) . Thus, with the method described here, it was possible to produce multilayer microcapsules which, for example, have an isocyanate content of only 0.6% by weight. However, the isocyanate content is preferably around 1.1% by weight of the capsule wall.
• the at least one polymerizable isocyanate and / or isothiocyanate is first dissolved in an inert, non-aqueous solvent or solvent mixture together with the active ingredient (s) to be encapsulated.
• the active ingredient to be encapsulated is preferably a hydrophobic active ingredient.
• Suitable inert solvents for the internal non-aqueous phase are: chlorinated diphenyl, chlorinated paraffin, vegetable oils such as cottonseed oil, peanut oil, palm oil, tricresyl phosphate, silicone oil, dialkyl phthalates, dialkyl adipates, partially hydrogenated terphenyl, alkylated biphenyl, alkylated naphthalene, diaryl ether, Aryl alkyl ethers and higher alkylated benzene, benzyl benzoate, isopropyl myristate and any mixtures of these hydrophobic solvents and mixtures of one or more of these hydrophobic solvents with kerosene, paraffins and / or isoparaffins.
• Vegetable oils such as sunflower oil, triglycerides, benzyl benzoate or isopropyl myristate are preferably used as solvents for providing the internal non-aqueous phase.
• the proportion of the active ingredient component to the internal non-aqueous phase is preferably about 1:14.
• the internal non-aqueous phase can therefore be encapsulated, for example, from 88 to 99% by weight and preferably from 92 to 96% by weight (Hydrophobic) active ingredient (or active ingredient mixture) based on the entire active ingredient capsule.
• the capsule as a whole, in this context, includes both the oil core, i.e. H. the active ingredient (or the active ingredient mixture) and the capsule wall components formed from isocyanate components and the respective crosslinkers from the external aqueous phase.
• the first step of the method described herein comprises providing an external aqueous phase which comprises at least one protective colloid.
• the protective colloid is dissolved in the aqueous solvent (preferably water).
• the protective colloid is preferably a polysaccharide, particularly preferably starch.
• a particularly preferred embodiment of the present invention relates to a method for producing multilayer microcapsules, in which the protective colloid is a polysaccharide, in particular starch.
• a protective colloid is a compound that is used in precipitation reactions, d. H. in reactions in which a solid phase is separated from a homogeneous liquid phase, clumping (agglomeration, aggregation, flocculation, coagulation) of the primary particles is prevented.
• the protective colloid attaches itself to the primary particles with its hydrophobic part and uses its polar, i.e. H. hydrophilic part of the molecule, to the aqueous phase. This accumulation at the interface lowers the interfacial tension and prevents agglomeration of the primary particles. In addition, it stabilizes the emulsion and promotes the formation of comparatively smaller droplets and thus also corresponding microcapsules.
• the protective colloid used in the method according to the invention is preferably a polysaccharide, particularly preferably starch, in particular starch from wheat, potatoes, corn, rice, tapioca or oats, or chemically, mechanically and / or enzymatically modified starch (succinates, acetates, Formates), as well as mixtures of the aforementioned compounds.
• Further suitable protective colloids are carboxymethyl celluloses, gum arabic, proteins, gelatin, polyols, polyphenols or polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl alcohol derivatives, such as ammonium derivatives, and mixtures of the aforementioned compounds.
• starches are used as the protective colloid. It is therefore particularly preferred to use (modified) starch as a protective colloid to produce the multilayer microcapsules.
• the protective colloids used herein have a double function in that, on the one hand, they react with the isocyanate (s) with polymerization to form a first or further crosslinking layer, and thus build up the capsule wall or capsule shell and are an integral part of this, and on the one hand others by acting as a protective colloid and thus preventing the agglomeration of the solid particles, stabilizing the emulsion subsequently formed and thus promoting the formation of small droplets.
• the selected protective colloid has polymerizable properties, for example in the case of starch due to the presence of at least one hydroxyl group.
• Starches are naturally occurring polysaccharides that are biodegradable. In combination with the isocyanates described herein, bio-based and biodegradable capsule shells can thus be provided with the present method. In the process described here, the starch therefore functions primarily as a so-called bio-crosslinker.
• the ratio of the amount of protective colloid or protective colloids used, based on the aqueous phase is preferably in a range from 1:50 to 1:10, more preferably in a range from 1:40 to 1:30.
• the amount of protective colloid used or the amount of a combination of protective colloids used is thus in a range from 1 to 8% by weight, preferably in a range from 2 to 4% by weight, even more preferably in a range of 3 to 4% by weight, based on the total weight of the external aqueous phase.
• the oil-in-water emulsion is formed by mixing the internal non-aqueous phase and the external aqueous phase.
• the weight ratio of the internal non-aqueous phase to the external aqueous phase is preferably in a range from 2: 1 to 1:10, more preferably in a range from 1: 2 to 1: 4.
• the ratio of protective colloid in the external aqueous phase to isocyanate or isothiocyanate in the internal non-aqueous phase is in a range from 1: 5 to 1: 2, preferably in a range from 1: 2 to 1: 1.
• emulsions in the case of liquid active ingredients or suspension formation in the case of solid active ingredients, d. H. the emulsification or suspension of the internal non-aqueous or oily phase with the external aqueous or hydrophilic phase takes place under high turbulence or strong shear, the strength of the turbulence or the shear determining the diameter of the microcapsules obtained.
• the production of the microcapsules can be carried out continuously or discontinuously. As the viscosity of the aqueous phase increases or the viscosity of the oily phase decreases, the size of the resulting capsules generally decreases.
• the process according to the invention for producing multilayer microcapsules can be carried out, for example, using a forced metering pump using the “inline” technique, or else in conventional dispersion apparatus or emulsifying apparatus with stirring.
• the external aqueous phase and the internal non-aqueous phase were emulsified for the production of multilayer microcapsules according to the invention by means of an emulsification turbine (IKA Eurostar 20 high-speed stirrer).
• the process of emulsification in the first step of the method according to the invention is advantageously carried out for a time of 30 seconds to 20 minutes, preferably from 1 to 4 minutes, at a Stirrer speeds of 2000 rpm to 5000 rpm, preferably 3250 rpm to 4500 rpm, are carried out.
• so-called stabilizers or emulsifying aids in the external aqueous phase in order to stabilize the emulsion formed and to separate the internal non-aqueous (oily / organic / hydrophobic) phase and the external aqueous (hydrophilic) phase ) Phase to prevent.
• a capsule shell or capsule wall can form through interfacial polymerization, which encloses the active ingredient (s) in its interior as a capsule core.
• this first capsule layer is based on the polyaddition reaction of the isocyanate or the isocyanates (and / or the corresponding isothiocyanates) with the (preferably polymerizable) protective colloid, preferably starch, with the formation of a capsule shell or capsule wall based on a polyurethane structure.
• a preferred embodiment of the present invention therefore relates to a method for producing multilayer microcapsules, in which the first crosslinking layer is formed from protective colloid and isocyanate in the presence of a catalyst.
• the catalyst which is added in the process according to the invention is preferably diazabicyclo [2.2.2] octane (DABCO).
• DABCO also known as triethylenediamine (TEDA), a bicyclic, tertiary amine.
• DABCO is generally used as a catalyst in the manufacture of polyurethane plastics.
• the tertiary amine with lone pairs of electrons favors the reaction between the at least one polymerizable isocyanate in the internal non-aqueous phase and the hydroxyl groups (alcohol groups) of the protective colloid in the external aqueous phase.
• the amount in which the catalyst is added to the emulsion or suspension is in a range from 0.01 to 1% by weight and preferably in a range from 0.05 to 0.2% by weight, based on the total weight of the emulsion or suspension. In the case of a slow polymerization reaction, the required amount of catalyst can be adjusted accordingly.
• the ratio of catalyst in the emulsion or suspension to the at least one isocyanate or isothiocyanate in the internal non-aqueous phase is thus preferably in a range from 1:20 to 1:50.
• the catalyst is first dispersed in water and then added to the emulsion or suspension with stirring.
• the addition of the catalyst is preferably carried out at a stirring speed of 500 rpm to 2000 rpm, particularly preferably 1000 rpm to 1500 rpm and at temperatures of 20 ° C to 35 ° C, preferably at Temperatures from 22 ° C to 26 ° C.
• Capsules produced in this way have a significantly higher stability, even after 10 days at 50 ° C., and a significant reduction in the free perfume oil compared to comparison capsules in which the catalyst is already added in the aqueous phase before emulsification or suspension.
• Particularly stable capsules could be produced with the catalyst diazabicyclo [2.2.2] octane (DABCO). In the herein described In this way, an increase in stability by at least a factor of 3 could be observed in the examples.
• DABCO diazabicyclo [2.2.2] octane
• the catalyst is therefore diazabicyclo [2.2.2] octane (DABCO).
• the present invention also relates to a method for producing multilayer microcapsules, comprising the addition of a catalyst in a step a4) after step a3).
• a first crosslinking layer is formed at the interfaces of the emulsified or suspended active ingredient particles or droplets to be encapsulated by interfacial polymerization, which is the inner first capsule shell, while the hydrophobic ones to be encapsulated Active ingredient particles or drops represent the core of the microcapsules according to the invention.
• the interfacial polymerization corresponds to a polyaddition reaction of the polyisocyanate (s) or isothiocyanate (s) (or mixtures thereof) with the protective colloid, i.e. H. preferably with starch, with the formation of a crosslinked polyurethane-based capsule shell in the presence of a catalyst.
• the addition of a catalyst therefore effects the efficient formation of the first innermost polyurethane-based shell layer.
• the polyaddition reaction described herein is generally characterized by the reaction of individual polymers or oligomers with two or more functional groups with bond formation and rearrangement of a hydrogen atom, such as, for example, by reaction of polyisocyanates or polyisothiocyanates and polyols (for example polysaccharides such as starch).
• a hydrophilic interface i. H. Forming a capsule shell which prevents the diffusion of the hydrophobic active ingredient (or the active ingredient mixture) enclosed in the capsule.
• this leads, for example, to an effective inclusion of the sensory perceptible active ingredient (fragrance mixture / perfume oil, individual fragrance), which is only effectively released through mechanical activation.
• linear polyurethane chains are generally formed which can be spatially crosslinked in a targeted manner through an excess of isocyanate over the amino groups of the uncrosslinked polyurethane chains.
• Further protective colloids or mixtures thereof and additional emulsifying aids or stabilizers are basically not necessary to ensure efficient crosslinking, but can optionally be added in order, in the event of insufficient crosslinking, on the one hand to improve the emulsification process or suspension process and on the other hand to improve the crosslinking density and rate to increase.
• a second crosslinking layer is formed by adding an amine which reacts at an acidic pH.
• an amine which reacts at an acidic pH is added to the mixture, likewise with stirring at a stirring speed of 500 rpm to 2000 rpm, particularly preferably 1000 rpm to 1500 rpm.
• Particularly stable crosslinking is achieved if the second crosslinking with the amine which reacts at an acidic pH takes place at an acidic pH of 2 to 7, preferably at a pH of 2 to 6 and most preferably at a pH value of 3 to 5.
• an acid for example formic acid or acetic acid
• acetic acid is added to the mixture to the external aqueous phase in order to set an appropriate pH value and to avoid potential saponification of the hydrophobic active ingredients. This ensures that the pH value does not drift too quickly and that the thin and still quite unstable first layer of protective colloid and isocyanate is penetrated.
• the core material d. H. the active ingredients, including the capsule shell, are further cross-linked, enclosed from the outside and thereby further stabilized.
• this layer preferably has a hydrophobic character and encloses the inner first hydrophilic crosslinking layer and thus acts as an additional barrier layer which makes diffusion of the enclosed active ingredient more difficult.
• the second crosslinking step is carried out at a temperature of 35 ° C to 50 ° C. Temperatures from 40 ° C. to 45 ° C. are preferred.
• the amine which reacts at an acidic pH, i.e. H. the second crosslinking agent is selected from the group consisting of basic amino acids and their hydrochlorides, in particular lysine hydrochloride and / or ornithine hydrochloride, with lysine hydrochloride being particularly preferred as the crosslinking agent.
• amino acid-based amines of this type are particularly preferred. Carrying out this crosslinking in an acidic pH range has the advantage over crosslinking in a basic environment that hydrophobic active ingredients with aldehyde, carboxylic acid or ester functionalities during crosslinking with the at least one isocyanate or isothiocyanate do not saponify, as the first innermost shell layer is still quite unstable with regard to diffusion and similar processes.
• hydrophobic active ingredients in particular of hydrophobic active ingredients which have an aldehyde, carboxylic acid or ester functionality, is possible.
• a preferred embodiment of the present invention therefore relates to a method for producing multilayer microcapsules comprising a second / further crosslinking step, in which the acidic amine used for the crosslinking is an acidic amino acid hydrochloride, in particular lysine hydrochloride and / or ornithine hydrochloride .
• the amine which reacts at an acidic pH is added to the suspension or emulsion either directly in the form of a solid or in the form of an aqueous solution.
• the amino acid hydrochloride is preferably added in the form of a 5 to 40% solution, more preferably a 10 to 20% solution.
• the second crosslinking of the process according to the invention is preferably carried out over a period of between 5 minutes and 30 minutes with stirring and preferably for a period of between 10 and 20 minutes.
• a second crosslinking layer is formed by interfacial polymerization, which the the inner first capsule shell and the hydrophobic active ingredient particles or droplets contained therein.
• the interfacial polymerization corresponds to a polyaddition reaction of the at least one polyisocyanate or isothiocyanate (or mixtures thereof) with the amine which reacts at an acidic pH, i.e. the amine. H. preferably with amino acid hydrochlorides, in particular lysine hydrochloride and ornithine hydrochloride, with the formation of a cross-linked capsule shell based on polyurea.
• the polyurea linkage is formed in a manner analogous to the formation of the polyurethane linkage by polyaddition of the amine group of the amines (-NH) to the corresponding isocyanate, according to the following reaction scheme:
• Reaction scheme 2 Any starch that is still present can also be built into this layer as a secondary component, which further increases the stability of the second crosslinking layer.
• this second crosslinking layer is mainly based on a polyurea-like crosslinking as the main component, which defines this layer.
• a third spatially crosslinked shell layer is formed, the structure of which can be derived in principle analogously to the first innermost crosslinking layer of polyurethane.
• the further crosslinking with the hydroxyl group donor takes place at temperatures between 40 ° C and 60 ° C, and preferably at temperatures between 45 ° C and 55 ° C, more preferably at temperatures between 45 ° C and 50 ° C.
• the pH value necessary for crosslinking is set by means of an organic acid, such as, for example, formic acid or acetic acid. This step is optional, however, since the pH value is often shifted into the correct range due to the previous polymerization reaction.
• the concentration of the hydroxyl group donor in the aqueous solution is preferably 10% to 70%, and more preferably the concentration of the hydroxyl group donor in the aqueous solution is 40% to 60%.
• crosslinking described herein thus preferably leads to a third defined crosslinking layer around the core, which comprises the at least one active ingredient to be encapsulated.
• the hydroxyl group donor is preferably at least one polyol, comprising two or more functional hydroxyl groups, with good to very good water solubility at temperatures above 40 ° C, in particular the hydroxyl group donor is selected from the group consisting of Glycerine, propylene glycol and / or 1,3,5-trihydroxybenzene.
• the capsules according to the invention which have such an additional layer, primarily based on polyurethane, have significantly more stable properties than microcapsules without such an additional stabilizing layer. Furthermore, such multilayer microcapsules (according to the invention) show a significantly more efficient containment of the active ingredients.
• the addition of the hydroxyl group donor is carried out with stirring in accordance with the aforementioned stirring speeds for the formation of the preceding crosslinking layers based on polyurethane and polyurea.
• the present invention relates to a method for producing multilayer microcapsules, in which the hydroxyl group donor is a polyol with two or more functional hydroxyl groups, in particular glycerol, propylene glycol and / or 1,3,5-trihydroxybenzene.
• the hydroxyl group donor is a polyol with two or more functional hydroxyl groups, in particular glycerol, propylene glycol and / or 1,3,5-trihydroxybenzene.
• crosslinking structures of the protective colloid could be found as a secondary component.
• the present method for producing multilayer microcapsules optionally comprises a further crosslinking step by adding an amino acid, in particular an aromatic amino acid, more preferably by adding the amino acids histidine and / or tryptophan with stirring.
• the pH value necessary for crosslinking is optionally set by adding a sodium hydroxide solution.
• This step of further optional crosslinking is even more preferably carried out at a temperature from 50 ° C to 70 ° C, preferably from 55 ° C to 65 ° C.
• the corresponding amino acid and in particular the aromatic amino acid, preferably has aromatic rings of five to six carbon atoms and at least one nitrogen atom in the aromatic system and two or more amino groups or imine groups and is in particular histidine and / or tryptophan.
• the concentration of the (aromatic) amino acid in the aqueous solution is preferably 10% to 70%, and more preferably 40% to 60%.
• the further / additional optional crosslinking in the process according to the invention takes place over a period of about 5 minutes to 30 minutes and preferably within 10 minutes to 20 minutes at a stirring speed of 500 rpm to 2000 rpm, preferably 1000 RPM and 1500 RPM.
• this additional, optional crosslinking step is carried out after the crosslinking step described below by adding at least one amine which reacts at an alkaline pH.
• the invention described herein comprising a method for producing multilayer microcapsules therefore further comprises at least one fourth crosslinking layer by adding at least one amine which reacts at an alkaline pH to obtain multilayered microcapsules with formation of a defined polyurea-based crosslinking layer around the crosslinking layers described above .
• the layers can be partially interwoven. Furthermore, all layers can thus have proportions of crosslinked protective colloid.
• the step of at least fourth crosslinking is carried out at a temperature from 60 ° C to 80 ° C, and preferably at 65 ° C to 75 ° C and particularly preferably at temperatures from 60 ° C to 70 ° C and while stirring.
• the amine which reacts at an alkaline pH value is preferably a guanidinium group donor and is selected from the group consisting of di-, tri- and polyamines, arginine, guanidinium hydrochloride and / or guanidinium carbonate. Most preferred, however, is guanidinium carbonate as the crosslinking agent for forming the at least fourth crosslinking layer.
• the concentration of the guanidinium group donor in the aqueous solution is preferably 1% to 50%, and more preferably 10% to 25%.
• the stirring speed used here is advantageously between 500 rpm and 2000 rpm and preferably between 1000 rpm and 1500 rpm for 5 minutes to 30 minutes and preferably for 10 minutes to 20 minutes.
• the suspension or emulsion then preferably has a pH of 7 to 8.
• the pH value necessary for further crosslinking is optionally set, for example by means of formic acid or acetic acid or by means of a sodium hydroxide solution.
• a preferred embodiment of the present invention relates to a method for producing multilayer microcapsules comprising the formation of at least a fourth crosslinking layer, in which the alkaline amine is a guanidinium group donor, in particular arginine, guanidinium carbonate and / or guanidinium hydrochloride .
• the present invention also relates to a method comprising an additional optional step before curing, in which the microcapsule crosslinking is terminated by adding an amine having an amine functional group.
• the amine with a functional amine group described herein is preferably a corresponding amino acid, in particular Alanine, glycine, aspartic acid, cysteine and / or proline, and serves to complete the last crosslinking layer and has no spatial crosslinking, but closes the network locally by incorporating the corresponding building blocks into the last outermost crosslinking layer.
• the termination of the outermost crosslinking layer or the microcapsule in an additional optional step before curing takes place at a pH of 6 to 11, and preferably at a pH of 7 to 9, and optionally at a temperature of above 75 ° C, preferably at a temperature of 75 ° C to 85 ° C in order to shorten the reaction time.
• the final amines are preferably added in aqueous form at concentrations of preferably 1% to 50%, and preferably at concentrations of 10% to 25%, with stirring.
• stirring is carried out at 500 rpm to 2000 rpm, preferably 1000 rpm to 1500 rpm, for between 1 and 10 minutes or preferably for 2 to 5 minutes.
• a further preferred embodiment of the present invention relates to a method according to the invention in which the amine used in an additional optional step before hardening to terminate the microcapsule is an amino acid, in particular an amino acid comprising an amino group, more preferably alanine, glycine , Aspartic acid, cysteine and / or proline.
• This additional step which closes the capsule wall or capsule shell, surprisingly leads to even more stable and more efficiently enclosing microcapsules, while at the same time it was possible to reduce the total shell material required.
• the hardening after the last crosslinking step or the final step of the multilayer capsules formed takes place at a temperature of about 80 ° C. and usually for 60 to 240 minutes. It is also advantageous to add hardening substances to the external aqueous phase. These substances are, for example, natural vegetable tanning agents.
• the present invention and the method described herein for producing multilayer microcapsules comprising layers based on polyurethane and polyurea are distinguished in particular by the choice of different pH ranges for carrying out the individual crosslinking steps.
• the composition transition between the layers can be steep, i.e. the layers are materially delimited and defined as far as possible.
• the crosslinkings described here can also be carried out at room temperature, but result in broad gradients, lower stabilities and long reaction times.
• the method described herein it is consequently possible to alternately layer defined polyurethane and polyurea-based crosslinking layers around the core, comprising at least one hydrophobic active ingredient, and thereby to produce a stable, multilayered capsule wall or capsule shell.
• the main components of the respective layers are basically polyurea or polyurethane links.
• the protective colloid for example Starch
• Partial cross-links between the individual alternating layers cannot be ruled out to a certain extent.
• the following layers are basically formed by means of the present method: a first layer comprising or consisting of polyurethane structures, a second layer comprising or consisting of polyurea structures, a third layer comprising or consisting of polyurethane structures, and at least a fourth layer comprising or consisting of polyurea structures.
• the first innermost capsule layer is essentially composed of a polyurethane-based crosslinking matrix (step a), followed by an essentially polyurea-based second crosslinking layer (step b).
• the third layer is again preferably crosslinked on the basis of polyurethane (step c), while the at least fourth outermost layer preferably essentially has a polyurea-based crosslinking system (step d).
• Further additional or final crosslinking layers for example based on polyurea through the crosslinking of further amines, such as amino acids, are optionally conceivable, which bring about an additional gain in stability through additional further crosslinking.
• the multi-layered and hardened microcapsules formed in this way are then separated from the reaction solution and optionally dried.
• the microcapsules produced by the process according to the invention are in the form of a dispersion in water, which is also referred to as a microcapsule dispersion.
• the microcapsules are basically already salable; however, it is recommended to dry them for preservation purposes. Suitable drying processes are, for example, lyophilization or spray drying.
• the present invention is further characterized in that amino acids are preferably mixed with starch and isocyanates as the main component targeted catalyzed mechanisms are networked and thus enable the production of bio-based and biodegradable microcapsules based on biocompatible polymers.
• the method described herein can be used to produce microcapsules which, due to the multiple and more efficient crosslinking layers, allow significant savings in shell material and thus make it possible to further reduce the required isocyanate content compared to capsules of the prior art, without being disadvantageous affect the stability of the capsules. This can be justified on the one hand by the more efficient and defined crosslinking of the individual layers and on the other hand by the generally alternating / different composition of the individual capsule shell layers.
• the multilayer microcapsules according to the invention thus have a significantly lower proportion of isocyanate overall compared to capsules of the prior art.
• the absolute isocyanate content of the microcapsules described herein corresponds to only 1 / 50th of the total capsule which comprises the active ingredient (s).
• the isocyanates do not directly form a component of the capsule wall or capsule shell, but rather merely act as a crosslinker between the, for example, significantly larger starch molecules.
• the raw materials react quantitatively, it can be assumed that with 100% wall material exactly 1/5 of the wall material consists of isocyanates and, due to the small amount in which they are represented, these can only be viewed as crosslinkers.
• microcapsules in which the ratio of the capsule shell to the total capsule volume of 1 to 14 could be reduced to 1 to 21 and thus the overall required casing material could be significantly reduced without suffering any loss of stability, as in the following exemplary embodiments is illustrated. While the proportion of the capsule wall material in the prior art (pure polyurea capsule) is 6.8% by weight compared to the total capsule (capsule consisting of active ingredient and capsule wall material), the multilayer microcapsules described here have a reduction in the capsule wall material to 4 , 4% by weight possible despite additional gains in stability.
• the method described herein enables the production of stable microcapsules in which the amount of necessary capsule wall material compared to capsules of the prior art, and in particular the amount of isocyanate required, could be significantly reduced while at the same time the amount of active ingredient to be encapsulated (active ingredient mixture) could not be reduced must become.
• the protective colloid preferably starch
• the protective colloid for example starch, forms an essential component of the first polyurethane-like crosslinking, which is already formed at a temperature of 25 ° C to 40 ° C by reaction with the catalyst.
• the double function of the protective colloid as a stabilizing factor of the emulsion and as a reactant, for example compared to polyvinyl alcohol, is further improved.
• the microcapsules according to the invention comprise in their core at least one active ingredient to be encapsulated as core material, which preferably has hydrophobic properties.
• any material that is suitable for inclusion in microcapsules can be used as the core material for producing the multilayer microcapsules according to the invention.
• the materials to be encapsulated are preferably hydrophobic, water-insoluble or water-immiscible liquids or solids and suspensions.
• hydrophobic active ingredient means that the material to be encapsulated is in the internal non-aqueous phase and does not mix with the external aqueous phase.
• the microcapsules according to the invention are designed in such a way that they contain a core material composed of at least one hydrophobic active ingredient, in particular a hydrophobic fragrance or fragrance or a hydrophobic fragrance or perfume oil (fragrance or fragrance mixture), a pesticide, a biocide, an insecticide, a substance from the group of repellants, food additives, cosmetic active ingredients, pharmaceutical active ingredients, dyes, agrochemicals, dyes, luminous colors, optical brighteners, solvents, waxes, silicone oils, lubricants, and mixtures of the have the aforementioned active ingredients, d. H. as long as this is sufficiently insoluble in water or does not mix with the water phase, since otherwise no emulsion will form and no deposition of the polymer on the droplet surface can take place.
• a hydrophobic active ingredient in particular a hydrophobic fragrance or fragrance or a hydrophobic fragrance or perfume oil (fragrance or fragrance mixture)
• a pesticide in particular a hydrophobic fragrance or fragrance or a hydro
• fragrances or fragrance oils or fragrances or fragrances are used as active ingredients.
• Fragrance mixtures perfume oils
• aromas or also biogenic principles can be considered.
• the microcapsules according to the invention have a core material in the form of a hydrophobic individual fragrance or individual fragrance, the core material comprising at least one individual fragrance or individual fragrance or mixtures thereof selected from one or more of the following groups:
• hydrocarbons such as B. 3-carene; a-pinene; beta-pinene; alpha-terpinene; gamma terpinene; p-cymene; Bisabolene; Camphene; Caryophyllene; Cedren; Ferns; Limonene; Longifolene; Myrcene; Ocimen; Valencene; (E, Z) -1, 3,5- undecatriene;
• Aliphatic alcohols such as. B. hexanol; Octanol; 3-octanol; 2,6-dimethylheptanol; 2-methylheptanol, 2-methyloctanol; (E) -2-hexenol; (E) - and (Z) -3-hexenol; 1-octen-3-ol; 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;
• Aliphatic nitriles such as. B. 2-nonenenitrile; 2-tridecenoic acid nitrile; 2,12-tridecenoic acid nitrile; 3,7-dimethyl-2,6-octadienoic acid nitrile; 3,7-dimethyl-6-octenonitrile; - Aliphatic carboxylic acids and their esters, such as. B.
• terpene alcohols such as. B. Citronellol; Geraniol; Nerol; Linalool; Lavadulol; Nerolidol; Farnesol; Tetrahydrolinalool; Tetrahydrogeraniol; 2,6-dimethyl-7-octen-2-ol; 2,6-dimethyloctan-2-ol; 2-methyl-6-methylen-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, isovalerianates, pen
• terpene aldehydes and ketones such as.
• Cyclic terpene alcohols such as. B. menthol; Isopulegol; ⁇ -terpineol; Terpinenol-4; Menthan-8-ol; Menthan-1-ol; Menthan-7-ol; Borneol; Isoborneol; Linalool oxide; Nopoly; Cedrol; Ambrinol; Vetiverol; Guajol; and their formates, acetates, propionates, isobutyrates, butyrates, isovalerianates, pentanoates, hexanoates, crotonates, tiglinates, 3-methyl-2-butenoates;
• Mercaptomenthan-3-one Carvone; Camphor; Fenchone; a-ionon; beta-ionon; a-n-methylionone; beta-n-methylionone; a-isomethylionone; beta-isomethylionone; a-iron; ß-lron; a-damascenone; beta-damascenone; gamma damascenone; d-damascenone; 1 - (2,4,4-trimethyl-2-cyclohexen-1-yl) -2-buten-1-one;
• Cyclic alcohols such as. B. 4-tert-butylcyclohexanol; 3,3,5-trimethylcyclohexanol; 3-isocamphylcyclohexanol; 2,6,9-trimethyl- (Z2, Z5, E9) cyclododecatrien-1-ol; 2-isobutyl-4-methyltetrahydro-2H-pyran-4-ol; from the group of cycloaliphatic alcohols such as. B.
• Cyclic and cycloaliphatic ethers such as. B. cineole; Cedryl methyl ether;
• Cyclododecyl methyl ether (Ethoxymethoxy) cyclododecane; a-cedrene epoxide; 3a, 6,6,9a-tetramethyldodecahydronaphtho [2, 1 -b] furan; 3a-ethyl-6,6,9a-trimethyl-dodecahydronaph-tho [2,1-b] furan; 1,5,9-trimethyl-13-oxabicyclo [10,1 0] trideca-4,8-diene; Rose oxide; 2- (2,4-dimethyl-3-cyclohexen-1-yl) -5-methyl-5- (1-methylpropyl) -1, 3-dioxane;
• Cyclic ketones such as B. 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-
• Methylcyclopentadecanone 4- (1-ethoxyvinyl) -3,3,5,5-tetramethylcyclohexanone; 4-tert-pentylcyclohexanone; 5-cyclohexadecen-1-one; 6,7-dihydro-1, 1, 2,3,3-pentamethyl-4 (5H) -indanone; 9-cycloheptadecen-1-one; Cyclopentadecanone; Cyclohexadecanone;
• Aromatic hydrocarbons such as. B. styrene and diphenylmethane;
• - Araliphatic alcohols such as. B. benzyl alcohol; 1-phenylethyl alcohol; 2-phenylethyl alcohol; 3-phenylpropanol; 2-phenylpropanol; 2-phenoxyethanol; 2,2-dimethyl-3-phenylpropanol; 2,2-dimethyl-3- (3-methylphenyl) propanol; 1,1-dimethyl-2-phenyl-ethyl alcohol; 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;
• Cinnamyl acetate 2-phenoxyethyl isobutyrate; 4-methoxybenzyl acetate; - Araliphatic ethers, such as. B. 2-phenylethyl methyl ether; 2-
• Aromatic and araliphatic aldehydes such as. B. benzaldehyde; Phenylacetaldehyde; 3-phenylpropanal; Hydratropaaldehyde; 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; a-butyl cinnamaldehyde; ⁇ -amylcinnamaldehyde; ⁇ -hexyl cinnamaldehyde; 3-methyl-5-phenylpentanal; 4-methoxybenzaldehyde; 4-hydroxy-3-methoxybenzaldehyde; 4-hydroxy-3-ethoxybenzal
• Aromatic and araliphatic ketones such as. B. acetophenone; 4-
• Aromatic and araliphatic carboxylic acids and their esters such as. B.
• Nitrogen-containing aromatic compounds such as. B. 2,4,6-trinitro-1,3-dimethyl-5-tert-butylbenzene; 3,5-dinitro-2,6-dimethyl-4-tert-butyl acetophenone; Cinnamonitrile; 5-phenyl-3-methyl-2-pentenoic acid nitrile; 5-phenyl-3-methylpentanoic acid nitrile; Methyl anthranilate; Methyl N-methyl anthranilate; Schiff's bases of methyl anthranilate with 7-hydroxy-3,7-dimethyloctanal, 2-methyl-3- (4-tert-butylphenyl) propanal or 2,4-dimethyl-3-cyclohexenecarbaldehyde; 6-isopropylquinoline; 6-isobutylquinoline; 6-sec-butylquinoline; Indole; Skatole; 2-methoxy-3-isopropylpyrazine; 2-is
• Phenols, phenyl ethers and phenyl esters such as. B. estragole; Anethole; Eugenol; Eugenyl methyl ether; Isugenol; Isougenyl methyl ether; Thymol; Carvacrol; Diphenyl ether; beta-naphthyl methyl ether; beta-naphthyl ethyl ether; beta-naphthyl isobutyl ether; 1,4-dimethoxybenzene; Eugenyl acetate; 2-methoxy-4-methylphenol; 2-ethoxy-5- (1-propenyl) phenol; p-cresylphenyl acetate; from the group of heterocyclic compounds such.
• lactones such as B. 1,4-octanolide; 3-methyl-1,4-octanolide; 1,4-nonanolide; 1.4-
• scented oils or perfume oils are used as the core material or as the active ingredients used. These are compositions that contain at least one fragrance. Such compositions, in particular scented oils or perfume oils, preferably comprise two, three, four, five, six, seven, eight, nine, ten or more fragrances.
• the fragrance oils or perfume oils are preferably selected from the group of extracts from natural raw materials, such as essential oils, concretes, absolutes, resins, resinoids, balms, tinctures such as. B.
• flavorings can also be encapsulated as core material in the form of an individual flavor, the core material comprising at least one individual flavoring or mixtures thereof as active ingredient.
• Typical examples of aromas which can be encapsulated for the purposes of the invention are selected from the group consisting of: acetophenone; Allyl caproate; alpha-ionon; beta-ionon; Anisaldehyde; Anisyl acetate; Anisyl formate; Benzaldehyde; Benzothiazole; Benzyl acetate; Benzyl alcohol; Benzyl benzoate; betalonone; Butyl butyrate; Butyl caproate; Butylidene phthalide; Carvone; Camphene; Caryophyllene; Cineole; Cinnamyl acetate; Citral; Citronellol; Citronellal; Citronellyl acetate; Cyclohexyl acetate; Cyclohexyl acetate; Cy
• Hedion® 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 caproate; trans-2-hexenyl caproate; cis -3-hexenyl formate; cis-2-hexyl acetate; cis-3-hexyl acetate; trans-2-hexyl acetate; cis -3-hexyl formate; para-hydroxybenzyl acetone; Isoamyl alcohol; Isoamyl isovalerate; Isobutyl butyrate; Isobutyraldehyde;
• fragrances or fragrances or aromatic substances are used in the production of the multilayer microcapsules, which are selected from the group consisting of: AGRUMEX LC; AGRUNITRIL; ALDEHYDE C11 UNDECYLENIC; ALDEHYDE C12 LAURIN; ALDEHYDE C12 MNA; ALDEHYDE C14 SOG; ALDEHYDE C16 SOG .; ALLYLAMYL GLYCOLATE; ALLYLCAPRONATE; ALLYLCYCLOHEXYLPROPIONATE; ALLYLHEPTYLATE; AMBROCENIDE® 10 TEC; AMBROCENIDE® Krist. 10% IPM; AMBROXIDE; ANETHOL NAT.
• biogenic principles can also be encapsulated as core material, the core material comprising at least one biogenic principle or mixtures thereof.
• Biogenic principles are to be understood as meaning active ingredients with biological activity, for example tocopherol, tocopherol acetate, tocopherol palmitate, ascorbic acid, carnotine, carnosine, caffeine, (deoxy) ribonucleic acid and its fragmentation products, ⁇ -glucans, retinol, bisabolhenol, allantoin, phytantriol , AHA acids, amino acids, ceramides, pseudoceramides, essential oils, plant extracts and vitamin complexes.
• the present invention therefore relates to a method for producing multilayer microcapsules, in which the at least one, preferably hydrophobic, active ingredient to be encapsulated is selected from the group consisting of odoriferous substances, fragrances, aromatic substances, biocides, insecticides, a substance from the group of repellants, food additives, cosmetic active ingredients, pharmaceutical active ingredients, agrochemicals, dyes, luminescent colors, optical brighteners, solvents, waxes, silicone oils, lubricants, and mixtures of the aforementioned active ingredients; the active ingredient is particularly preferably a fragrance or a fragrance mixture and is therefore preferably a hydrophobic fragrance or fragrance or a hydrophobic fragrance or fragrance mixture.
• the active ingredient is particularly preferably a fragrance or a fragrance mixture and is therefore preferably a hydrophobic fragrance or fragrance or a hydrophobic fragrance or fragrance mixture.
• microcapsules are distinguished by excellent stability and excellent releasability.
• the multilayer microcapsules produced in this way also show excellent sensory properties, which can be attributed to the stable active ingredient encapsulation and the associated low loss of active ingredient.
• a particularly defined and good sequence of process steps leads to these defined, dense and very thin capsule shells or capsule walls, which, as a quartet, synergistically establish the very good sensory performance of the capsules.
• particularly thin capsule walls or capsule shells can be produced, which nevertheless result in the analytical stability being maintained (active ingredient in the capsule) and the sensory performance being further improved.
• corresponding odorous substance capsules which have been produced by the method according to the invention have a higher stability and a reduction in unintentionally escaping perfume oil, which can be attributed in particular to a more efficient encapsulation of the odorous substances. Capsules produced in this way therefore show a significantly higher odor intensity when fragrance is released by opening the capsules by means of mechanical friction or pressure.
• the present invention therefore also relates to multilayer microcapsules, comprising at least one hydrophobic fragrance or fragrance, produced by a method described herein.
• microcapsules comprising multilayer capsule shells or capsule walls have particularly good active ingredient release properties, while at the same time they have a significantly lower polymer content (capsule wall constituents).
• polymer content capsule wall constituents.
• there is a universal capsule which, as things stand today, can encapsulate many or even every tested fragrance or odorant.
• An additional aspect of the present invention relates to multilayer microcapsules, comprising a core comprising at least one hydrophobic fragrance or odoriferous substance, and a capsule shell, wherein the capsule shell from the inside outwards comprises or consists of:
• the microcapsules produced by the method according to the invention have a multilayer capsule shell which basically has a first innermost layer based on polyurethane, a second layer based on polyurea, a third layer based on polyurethane and at least a fourth comprises outermost layer based on polyurea.
• the first, innermost barrier layer is formed primarily through crosslinking of the at least one isocyanate and the protective colloid, for example a polysaccharide.
• the second crosslinking step results primarily from the polyaddition of isocyanates and the acidic amine, for example an amino acid, while the third crosslinking layer primarily results from a reaction between isocyanates and the hydroxyl group donor.
• the capsule is enveloped by at least one fourth crosslinking layer which is primarily formed by the reaction of isocyanates and at least one basic amine.
• the multilayer microcapsule according to the invention generally has an alternating shell system based on polyurethane and polyurea linkages, which gives the capsules a particularly high stability.
• the capsule wall Due to the structure of the capsule wall, based on several individual defined and alternating layers, which are formed by targeted depositions at defined temperatures and times and which support and enclose each other, it is possible, starting from the present invention, particularly stable microcapsules with excellent to produce sensory performance while at the same time a significant reduction of the shell components is possible.
• the present invention therefore relates to multilayer microcapsules, in which: (i) the first layer comprises crosslinked units of at least one isocyanate with two or more isocyanate groups and a protective colloid;
• the second layer comprises crosslinked units of at least one isocyanate having two or more isocyanate groups and an amine which reacts at an acidic pH;
• the third layer comprises crosslinked units of at least one isocyanate having two or more isocyanate groups and a hydroxyl group donor;
• the at least fourth layer comprises crosslinked units of at least one isocyanate with two or more isocyanate groups and at least one amine which reacts at an alkaline pH.
• the microcapsules described herein have higher stabilities and excellent sensory properties (excellent release capacity of the microcapsules), while overall less shell material was required compared to comparably stable capsules of the prior art, as in the following exemplary embodiments is illustrated.
• the present invention enables, for example, the provision of efficient fragrancing and flavoring systems by efficient encapsulation of hydrophobic fragrances and fragrances.
• microcapsules described herein it is also possible with the microcapsules described herein to encapsulate a broad spectrum of hydrophobic active ingredients. So that there are no longer any restrictions against individual active ingredients such as fragrances. This means that there is a universal capsule which, according to the current state of the art, can encapsulate most of the tested odoriferous substances.
• multilayer microcapsules are described in which the multilayer microcapsule comprises at least one bio-based and biodegradable fragrance or fragrance or a fragrance or fragrance mixture.
• microcapsules produced by the process according to the invention can be characterized by the d (0.5) value of their size distribution, i.e. H. that 50% of the capsules produced are larger, 50% of the capsules are smaller than this value.
• the microcapsules according to the invention are dispersed in water in a dynamic process and the particle size is then determined by means of laser diffraction. Depending on the size of the capsule, the laser beam is refracted differently and can thus be converted into a size.
• the Mie theory was used for this.
• a MALVERN Mastersizer 3000 was used for particle measurement.
• microcapsules according to the invention are characterized in that they have a particle size distribution with ad (0.5) value of 10 ⁇ m to 100 ⁇ m, preferably ad (0.5) value of 20 ⁇ m to 65 ⁇ m.
• ad (0.5) value 10 ⁇ m to 100 ⁇ m
• ad (0.5) value 10 ⁇ m to 100 ⁇ m
• ad (0.5) value 20 ⁇ m to 65 ⁇ m.
• FIG. 1 The direct comparison of the microcapsules shows that due to an improved emulsification process as described herein, a more homogeneous distribution in the particle size of the microcapsules compared to microcapsules of the prior art can be achieved.
• FIG. 5 the IR images of the microcapsules according to the invention and of microcapsules of the prior art are shown.
• the capsules according to the prior art correspond to microcapsules which have been produced according to known encapsulation technology and are based on a pure polyurea-based network. No catalyst was used for the production of such microcapsules and polyvinyl alcohol was chosen as the protective colloid.
• the Fier position also took place at a pFI value of 9.
• the graphic shows the clear difference between the bands, especially in the fingerprint area. Due to the significantly more intense band at 626 cm 1 of the multilayer microcapsules compared to the prior art, an asymmetrical stretching vibration of an OFI group can be concluded, which can be traced back to the modified starch used, for example.
• Another example is the band at 510 cm -1 , which can be assigned to an N-Fl oscillation of a polyurethane.
• the comparison of the IR spectra shows that, compared to capsules of the prior art (pure polyurea-based capsules), a new additional polymer has formed, to which the improved stabilities and sensory properties can be attributed (polyurethane cross-links).
• the microcapsules according to the invention are suitable for a wide range of applications and in particular for use in detergents, fabric softeners, cleaning agents, scent boosters (fragrance enhancers) in liquid or solid form, cosmetics, personal care products, agricultural products or pharmaceuticals Products and the like.
• scent boosters fragment enhancers
• the use of the multilayer microcapsule or a suspension of multilayer microcapsules for the production of detergents, fabric softeners, cleaning agents, scent boosters or fragrance enhancers in liquid or solid form, cosmetics, personal care products, agricultural products or pharmaceutical products is described .
• capsules were chosen as the prior art capsules, the capsule walls of which can be traced back exclusively to a polyurea network.
• no catalyst was used in the production of these capsules and the synthesis took place at a pH value of 9.
• Polyvinyl alcohol was chosen as the protective colloid.
• Example 1 stability data of multilayer microcapsules which were produced by the method according to the invention, with comparison capsules; general gain in stability.
• the stability data of the multilayer microcapsules produced according to the invention are compared with the stability data of corresponding microcapsules which have been produced without the addition of a catalyst.
• a catalyst for the production of the latter, a mixture of two different isocyanates from hexamethylene diisocyanate and 4,4'-methyldiphenylene diisocyanate in a ratio of 80:20, modified starch as protective colloid, and the crosslinking agent lysine hydrochloride (amine that reacts at an acidic pH) were used. , Glycerine (hydroxyl group donor) and guanidinium carbonate (amine that reacts at an alkaline pH). No catalyst was used in the manufacture of these capsules.
• the multilayer microcapsules according to the invention were produced from a mixture of two different isocyanates from hexamethylene diisocyanate and 4,4'-methyldiphenylene diisocyanate in a ratio of 80:20, modified starch as protective colloid, the catalyst DABCO, and the crosslinking agents lysine hydrochloride ( amine reacting at an acidic pH value), Glycerine (hydroxyl group donor) and guanidinium carbonate (amine that reacts at an alkaline pH value) according to the following scheme:
• Table 1 Production of the multilayer microcapsules by the method described herein.
• Both capsules comprised TomCap perfume oil.
• the starch used as protective colloid and crosslinker in the examples listed herein is generally in the form of a succinate.
• the starch is derivatized with succinic acid.
• the stability test was carried out using a representative softener (fabric softener) into which the corresponding microcapsules were incorporated in an amount of 1% by weight.
• the softener was then stored at a temperature of 50 ° C. for the periods specified below (see Table 1).
• Table 2 Stability data of multilayer microcapsules according to the invention in comparison with the stability data of comparison capsules produced without the use of a catalyst.
• the stability of the microcapsules is determined via the residual oil content (the perfume oil remaining in the microcapsule).
• the microcapsules produced are considered to be stable from a proportion of more than 40% residual oil after 10 days.
• the capsule contents after several days were analyzed by means of GC / MS (gas chromatography with mass spectrometry coupling).
• the perfume oil content in the capsules was determined by comparative measurement with a standard.
• a result of 46%, for example, means that 64% of the originally used amount of perfume oil is no longer enclosed in the capsule.
• Comparative capsules manufactured without the use of a catalyst, cannot form a first innermost capsule shell based on polyurethane (see
• Reaction scheme 1 whereby the capsule wall due to the lower number of Crosslinking layers overall has a lower stability. It should also be pointed out in this context that the catalyst was added at room temperature and that this first innermost crosslinking layer based on polyurethane is already formed efficiently at room temperature.
• Example 2 Stability data of multilayer microcapsules which were produced by the process according to the invention, with and without a hydroxyl group donor.
• the stability data of the multilayer microcapsules produced according to the invention are compared with the stability data of corresponding microcapsules which have been produced without the addition of a hydroxyl group donor, ie. H. with microcapsules without the additional polyurethane-based third capsule shell layer.
• the multilayer microcapsules according to the invention were made from a mixture of two different isocyanates of flexamethylene diisocyanate and 4,4'-methyldiphenylene diisocyanate in a ratio of 80:20, starch as protective colloid, the catalyst DABCO, and the crosslinking agents lysine flydrochloride (at an acidic pFI value reacting amine), glycerine (flydroxyl group donor) and guanidinium carbonate (amine reacting with an alkaline pFI value) [see Example 1]
• Table 3 Stability data of multilayer microcapsules according to the invention with and without an additional polyurethane-based crosslinking layer by adding a hydroxyl group donor (with / without adding a hydroxyl group donor).
• Example 3 Stability data of multilayer microcapsules which were produced by the process according to the invention, as a function of the point in time at which the catalyst was added.
• the stability data of the multilayer microcapsules produced according to the invention are compared with the stability data of corresponding microcapsules in which the catalyst was already added in the aqueous phase (i.e. in step a2).
• the multilayer microcapsules according to the invention were produced from a mixture of two different isocyanates
• Crosslinkers lysine hydrochloride (amine that reacts at an acidic pH value),
• Both capsules, the multilayer microcapsule according to the invention produced by the method described herein and the comparison capsule have an average particle size distribution of d (0.5)> 60 ⁇ m.
• Table 4 Stability data of multilayer microcapsules according to the invention as a function of the time at which the catalyst is added.
• the microcapsules according to the invention show a significantly higher stability, even after 10 days at 50 ° C., and a significant reduction of free perfume oil. This corresponds to an increase in stability by a factor of 3.
• the resulting shell material was 40% of the shell material of the microcapsules with flydroxyl group donor from Example 2. Despite the reduced amount of shell material required, multilayer microcapsules can be obtained by means of the method according to the invention which have excellent stabilities.
• Example 4 Sensory evaluation of the microcapsules according to the invention.
• the sensory evaluation of the microcapsules was carried out as follows: The microcapsules, as they are listed in FIG. 7, were incorporated into a fabric softener and then washed. It was smelled on mixed fiber cloths made of cotton and polyester.
• Both the capsules of the prior art (pure polyurea-based capsules) and the microcapsules according to the invention contain the perfume oil TomCap.
• the capsules of the prior art were produced exclusively via polyurea crosslinking. No catalyst was used for the production and polyvinyl alcohol was chosen as the protective colloid. The production took place at a pH value of 9. Such capsules thus have a purely polyurea-based shell network.
• the multilayer microcapsules according to the invention were produced as described in Example 1.
• microcapsules according to the invention have in fact the same odor profile as the microcapsules from the prior art. However, the test persons were able to perceive a significantly higher odor intensity on average with the untreated, kneaded and rubbed mixed-fiber cloths. The fragrance is released by mechanical destruction of the microcapsules according to the invention.
• the advantage is based on the stability of the microcapsules according to the invention.
• isocyanate-based encapsulations Another great advantage of isocyanate-based encapsulations is the fact that these capsules are formaldehyde-free. Furthermore, in comparison to the prior art, a gain in stability and sensory performance can be observed despite significantly lower amounts of polymer. This can be explained on the basis of the thin, multilayer capsule shells. At the same time, there are no restrictions on individual fragrances. That is, there is an almost universal one Capsule that can encapsulate almost every tested odoriferous substance according to the current state of the art.
• microcapsules from the prior art lose oil more quickly over time and thus smell less intensely than the microcapsules according to the invention.
• Example 5 Influence of the selected isocyanates on the stability of the multilayer microcapsules according to the invention.
• the multilayer microcapsules according to the invention were produced according to Example 1, with arginine being used instead of guanidinium carbonate.
• the microcapsules were produced from a mixture of two different isocyanates or from one isocyanate according to the table below, starch as protective colloid, the DABCO catalyst and the crosslinkers lysine hydrochloride (amine that reacts at an acidic pH), glycerine ( Hydroxyl group donor) and arginine (reactive amine at an alkaline pH value).
• the following table shows the direct comparison of the influence of the isocyanates selected for the production of the multilayer microcapsules according to the invention on the stability of the said microcapsules.
• Light microscope images of the corresponding microcapsules according to the invention are given in FIGS.
• Table 5 Comparison of the influence of the selected isocyanates on the stability of the multilayer microcapsules according to the invention.
• hexamethylene diisocyanate was chosen as the longer-chain diisocyanate
• Pentamethylene diisocyanate was used as a shorter chain diisocyanate
• 4,4‘-methyldiphenylene diisocyanate was chosen as the aromatic diisocyanate.
• the stabilities of the multilayer microcapsules produced according to the invention are compared with microcapsules produced without a hydroxyl group donor and / or a catalyst.
• the multilayer microcapsules according to the invention were produced from a mixture of two different diisocyanates / diisothiocyanates (mixture of hexamethylene diisocyanate and 4,4'-methyldiphenylene diisocyanate in a ratio of 80:20) with the same functionalities.
• the emulsion is formed at 25 ° C.
• Modified starch was chosen as the protective colloid and the crosslinkers were lysine hydrochloride (amine that reacts at an acidic pH), glycerine (hydroxyl group donor) and guanidinium carbonate (amine that reacts at an alkaline pH).
• the production of the microcapsules took place as in the production method according to Example 1 described herein.
• Table 6 Stability data of multilayer microcapsules according to the invention as a function of the influence of the hydroxyl group donor and the catalyst.
• microcapsules according to the invention with an additional polyurethane-based and an additional polyurea-based capsule shell show the best stability properties.
• the microcapsules produced in this way have a multilayer capsule wall of generally alternating crosslinked polyurethane and polyurea-based layers in the following order: first innermost layer comprising polyurethane structures, second layer comprising polyurea structures, third layer comprising polyurethane structures and fourth outermost layer comprising polyurea structures.
• Example 7 Influence of the selected temperature ranges.
• the influence of the temperature graduation of the individual steps a) to d) is determined using microcapsules according to the invention and capsules according to the prior art (pure polyurea-based capsules produced without a catalyst at a pH of 9 using polyvinyl alcohol as protective colloid).
• all reactants were added at room temperature.
• the following temperature ranges were selected for the addition of the individual components (the reactants were added as described in the present invention): - Addition of the catalyst DABCO: 22 to 26 ° C (step a4);
• step b Addition of the amine (lysine hydrochloride) which reacts at an acidic pH value: 40 to 45 ° C (step b);
• step c Addition of the hydroxyl group donor (glycerine): at 45 to 50 ° C (step c);
• step d Addition of the amine (guanidinium carbonate) which reacts at an alkaline pH value: 60 to 70 ° C (step d).
• Table 7 Stability data and polymer proportions of multilayer microcapsules and capsules according to the invention of the prior art.
• composition of the capsule wall components can ideally be described as follows:
• Table 8 Composition of the multilayer capsule shell or capsule wall.
• the microcapsules according to the invention show comparably good, if not even better, stability data.
• the improved stability can be attributed to the four-layer cover system.
• the specifically chosen temperatures bring about a more efficient crosslinking of the crosslinking building blocks and thus enable a reduction of the total required polymer content.
• Example 8 Stability data for microcapsules according to the invention with a reduced shell fraction.
• the multilayer microcapsules according to the invention were produced from a mixture of two different isocyanates (mixture of hexamethylene diisocyanate and 4,4'-methyldiphenylene diisocyanate in a ratio of 80:20), starch as protective colloid, the catalyst DABCO (added at 22 ° C to 26 ° C) ° C), as well as the crosslinkers lysine hydrochloride (amine reacting at an acidic pH value; addition at 40 ° C to 45 ° C), glycerine (hydroxyl group donor; addition at 45 ° C to 50 ° C) and guanidinium Carbonate (amine that reacts at an alkaline pH value; addition at 60 ° C to 70 ° C).
• the microcapsules according to the invention produced in this way thus have a capsule wall comprising basically four different crosslinking layers based on polyurethane and polyurea in an alternating sequence.
• the capsules of the prior art are conventional capsules with single-layer capsule walls based on a pure polyurea made from a mixture of hexamethylene diisocyanate and 4,4‘-methyldiphenylene diisocyanate in a ratio of 80:20 and guanidinium carbonate. These capsules were produced without the use of a catalyst at a pH of 9 using polyvinyl alcohol as a protective colloid.
• Table 9 Polymer proportions and stability data of multilayer microcapsules according to the invention and of capsules of the prior art.
• the increased number of individual layers results in a stable capsule with a reduced amount of polymer, which is more stable despite 36% less polymer (comparison of prior art to invention 1) and even with a fraction of the polymer amount of 16% of the initial amount (according to the invention 3) still stably encloses almost 50% of the oil in the capsule after 10 days at 50 ° C.
• Example 9 Stability data for microcapsules according to the invention as a function of the pH value used with regard to the formation of the first innermost crosslinking of the capsule shell or capsule wall from isocyanate and protective colloid.
• the microcapsules tested were prepared according to the method described herein.
• the isocyanate component was composed of a mixture of hexamethylene diisocyanate and 4,4‘-methyldiphenylene diisocyanate in a ratio of 80:20. DABCO acted as the catalyst, while starch was used as the protective colloid (see Example 1).
• Table 10 Stability data of the multilayer microcapsules as a function of the pH of the first polymerization with starch.
• capsules which have an inner polyurethane-based capsule shell made of starch and isocyanates have particularly stable properties when this first polymerization, i.e. H. the innermost capsule shell is formed at a pH of 7 to 9.
• the modified starch used could be used in a dual function at the same time as a protective colloid and as a reactant (capsule wall component / crosslinker).
• Example 10 Optional step before curing, in which a termination of the microcapsule crosslinking is formed by adding an amine with an amine functional group.
• microcapsules tested were prepared according to the method described herein. The following reactants were used for this: Two linear isocyanates and hexamethylene diisocyanate
• DABCO as a catalyst (addition at 25 ° C), lysine hydrochloride (addition at 40 ° C, glycerine (addition at 50 ° C) and arginine (addition at 60 ° C) and the amines Histidine or alanine (added at 80 ° C.)
• the last-mentioned amines are amino acids comprising an amino group.
• Table 11 Stability data of multilayer microcapsules comprising a final additional crosslinking.
• Example 11 Stability data of multilayer microcapsules and the influence of the protective colloid and the hydroxyl group donor on the stability of the multilayer microcapsules.
• the stabilities of the multilayer microcapsules produced according to the invention are shown as a function of the protective colloid (with / without PVOH or modified starch) and the hydroxyl group donor (with / without glycerol or phloroglucinol).
• microcapsules according to the invention were synthesized in principle as described in Example 1, with variations being made in accordance with the tables below.
• the microcapsules of the prior art are microcapsules based on pure polyurea. The individual components were added to the reaction mixture or suspension or emulsion within defined temperature ranges.
• the prior art capsule is a microcapsule based on a pure polyurea network. As a rule, no catalyst was used in the production of these capsules and the synthesis took place at a pH value of 9. Polyvinyl alcohol was chosen as the protective colloid.
• Table 12 Stability data of multilayer microcapsules according to the invention as a function of the influence of the hydroxyl group donor and the protective colloid.
• Table 13 Stability data of multilayer microcapsules according to the invention as a function of the influence of the hydroxyl group donor and the protective colloid.
• the table shows that, in contrast to a combination of modified starch and glycerol, a comparable system with phloroglucinol (1,3,5-trihydroxybenzene) gives poorer results. Surprisingly, not every polyol seems to enable these high gains in stability, so that, as expected, reactive triphenol, such as phloroglucinol as a hydroxyl group donor, with modified starch does not even lead to the formation of microcapsules.
• the hydroxyl group donor is therefore preferably a polyol with two or more functional hydroxyl groups, in particular glycerol and / or propylene glycol.

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