EP3500610A1 - Magnetic nanocapsules as thermolatent polymerization catalysts or initiators - Google Patents

Abstract

The present invention relates to a process for producing special nanocapsules employable as thermolatent polymerization catalysts, in particular for the polymerization of polyurethanes, by means of a high shear process, wherein the process comprises: (i) emulsifying a first reaction mixture (a) in a continuous aqueous phase comprising at least one stabilizer, wherein the first reaction mixture, based on the total weight of the reaction mixture, comprises 10.0 to 99.0 wt% of a monomer mixture, wherein the monomer mixture, based on the total weight of the monomer mixture, comprises (a1) 2.5 to 19.0 wt% of at least one ethylenically monounsaturated C₃-₅-carboxylic acid monomer; (a2) 76.0 to 97.5 wt% of at least one ethylenically monounsaturated C₃-₅-carboxylic acid-C₁-₁₀-alkyl ester monomer; and (a3) 0.0 to 5.0 wt% of at least one monomer bearing at least two ethylenically unsaturated groups; (ii) emulsifying a second reaction mixture (b) in a continuous aqueous phase comprising at least one stabilizer, wherein the second reaction mixture, based on the total weight of the reaction mixture, comprises: (b1) 1.0 to 80.0 wt% of magnetic nanoparticles; (b2) optionally 0.0 to 70.0 wt% of at least one polymerization catalyst or initiator; (b3) optionally 0.0 to 89.0 wt% of at least one hydrophobic release agent; and (b4) optionally 0.0 to 10.0 wt% of at least one ultrahydrophobic compound distinct from the release agent; (iii) combining the first reaction mixture from step (i) and the second reaction mixture from step (ii); and (iv) polymerizing the monomers. The invention further relates to the nanocapsules produced by means of the described processess, to the use thereof, and to agents which contain these nanocapsules.

Description

 "Magnetic Nanocapsules as Thermo-Latent Polymerization Catalysts or Initiators"

The present invention relates to a process for the preparation of special nanocapsules, which can be used as thermolatent polymerization catalysts / initiators, in particular for the polymerization of polyurethanes. The invention further relates to the nanocapsules prepared by the described methods, their use and agents containing these nanocapsules.

Polyurethanes are widely used materials that find application in a variety of fields.

However, especially for systems based on aliphatic isocyanates are often

Catalysts required to accelerate the polymerization reaction of polyurethanes and lower the cure temperatures. Be predominantly for this purpose

Organotin compounds, with dibutyltin dilaurate (DBTL) being the most widely used catalyst. Due to growing concerns about the toxicity of DBTL but other tin-based catalysts, such as

Zinnndodekanoat, used. However, a complete abandonment of tin-based catalyst systems would be particularly desirable from both ecological and health aspects.

In general, the catalysts used are highly reactive, which drastically shortens the pot life of PU materials. To overcome this disadvantage, a number of approaches are known, such as the use of blocked isocyanates or UV-curable systems. However, these in turn suffer from the fact that high temperatures are required for activation or that the applications are limited to those in which a UV activation is practicable. Another alternative is thermolatent catalysts, i.

Delayed-action catalysts which are heat-activated. Tin (II) and tin (IV) alkoxy catalysts, for example, have been proposed for this purpose (Zoller et al. (2013) Inorganic Chem. 52 (4): 1872-82). However, these require complex synthesis methods. Another alternative is systems based on a physical barrier, where

Microcapsules are already well established in the art. Microcapsules have a size of 1 to 1000 μιη and are usually opened mechanically by breaking, with the content is released. A disadvantage of microcapsules, however, is that they tend in the application for coagulation or sedimentation and their use is limited to applications in which the size of the capsules does not adversely affect, such as in infusion processes in the composite area, where the as a gain fibers used the complete Penetration of a gel with a microcapsule-containing polymer resin can prevent by retaining the microcapsules.

Nanocapsules represent an alternative to the known microcapsules. Due to their size in the range of only 50 to 500 nm (z-average from dynamic light scattering (DLS)), these capsules can not be mechanically opened by breaking open, but must be formulated in this way in that they open in response to certain signals or environmental conditions. However, it is difficult to achieve a high encapsulation efficiency with nanocapsules, which is due to the small size and the fact that the thin shell of the nanocapsules without special precautions or adjustments only very limited

Diffusion barrier can serve.

The object of the present invention was therefore to provide nanocapsules which overcome the existing disadvantages and are suitable as thermolatent catalysts.

The present invention solves this problem by providing the nanocapsules in one step by means of a combined emulsion / miniemulsion polymerization approach

Monomer mixture and to be encapsulated magnetic nanoparticles and optionally a hydrophobic release agent can be produced. Depending on the conditions of preparation, the nanocapsules obtainable in this way have different morphologies, the polymer formed from the monomers forming a shell or a matrix, and the magnetic nanoparticles and optionally the release agent forming the core or embedded in the polymer matrix become. The magnetic nanoparticles are able to catalyze the polyaddition reaction of compounds with isocyanate groups and NCO-reactive groups to form polyurethanes. For this reason, the use of customary catalyst / initiator substances, in particular tin-based catalyst / initiator substances, can be completely dispensed with.

The nanocapsules thus obtainable are thermolatent, i. The content of the nanocapsules can be released controlled by increasing the temperature. The release can also take place via alternative mechanisms. In the first case, the substances contained in the core of the nanocapsules at elevated temperature are themselves sufficiently compatible with the capsule shell to overcome the nanocapsule shell barrier (but at the temperatures used in the nanocapsule shell)

Encapsulation and storage used are sufficiently incompatible to allow encapsulation and prevent premature release). In the second case, the magnetic nanoparticles contained in the nanocapsules according to the invention by applying a heated external magnetic field according to the induction principle. By such heating of the nanocapsules above the glass transition temperature of the polymer shell, it becomes permeable or breaks up and the content of the nanocapsules localized in the core or in the polymer matrix is released in a targeted manner. Consequently, even in this case, the nanocapsules are sufficiently stable at temperatures prevailing during encapsulation and storage, thereby preventing premature release. In the third case, a release agent is used, which swells at elevated temperature, the capsule shell and thus makes the contents of the capsule, permeable. On the other hand, the elevated temperature release agent is sufficiently compatible with the capsule shell to have a softening effect but sufficiently incompatible at the temperatures used in manufacture and storage to allow for efficient encapsulation. In a fourth case, a blowing agent is used as the release agent, wherein the blowing agent is chosen such that it vaporizes at a fixed temperature and, due to the increasing pressure inside the nanocapsules, breaks them up, thereby liberating the catalyst.

The nanocapsules are also characterized by a very high encapsulation efficiency and a high colloidal stability and prevent the release of the capsule contents under standard conditions very effectively, so that formulated PU materials have extended pot life.

In a first aspect, therefore, the invention relates to a process for the preparation of nanocapsules containing magnetic nanoparticles, characterized in that the process comprises: (A)

 (i) emulsifying a first reaction mixture (a) into a continuous aqueous phase, in particular water, which comprises at least one stabilizer, in particular at least one surfactant, to produce a first emulsion, the first reaction mixture, based on the total weight of the reaction mixture, 10.0 to 99.0 wt .-% of a monomer mixture, wherein the monomer mixture, based on the total weight of

Monomer mixture, comprising:

 (a1) 2.5 to 19.0 wt .-%, in particular 5.0 to 12.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid monomer;

 (a2) 76.0 to 97.5 wt .-%, in particular 85.0 to 95.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid Ci-io-alkyl ester monomer; and

 (a3) 0.0 to 5.0 wt .-%, in particular 0.0 to 3.0 wt .-%, of at least one monomer which carries at least two ethylenically unsaturated groups, preferably one

Divinylbenzene or a di- or triester of a C2-C10 polyol with ethylenic unsaturated C 3 -C 5 -carboxylic acids, in particular a di- or triester of a C 2 -C 10 -alkanediol or triol with ethylenically unsaturated C 3 -C 5 -carboxylic acids;

 (ii) emulsifying a second reaction mixture (b) into a continuous aqueous phase, in particular water, which optionally comprises at least one stabilizer, in particular at least one surfactant, to produce a second emulsion, the second

 Reaction mixture, based on the total weight of the reaction mixture, comprises:

(b1) 1.0 to 80.0% by weight, preferably 10 to 70% by weight, in particular 30 to 60% by weight, of magnetic nanoparticles whose surface is preferably hydrophobicized, wherein the magnetic nanoparticles preferably comprise the polyaddition reaction of

 Catalyze compounds with isocyanate groups and NCO-reactive groups to give polyurethanes; and

 (b2) optionally 0.0 to 70.0 wt .-% of at least one polymerization catalyst or initiator, preferably a catalyst of the polyaddition reaction of

 Compounds with isocyanate groups and NCO-reactive groups catalyzed to polyurethanes; and

(b3) optionally 0.0 to 89.0% by weight of at least one hydrophobic release agent, wherein the release agent preferably has a Hansen parameter 5t of less than 20 MPa '²; and

 (b4) optionally 0.0 to 10.0% by weight of at least one ultrahydrophobic compound other than the release agent, preferably an optionally fluorinated C12-28 hydrocarbon, more preferably a C14-26 alkane;

 (iii) combining the first emulsion of step (i) with the second emulsion of step (ii); and

 (iv) polymerizing the monomers; or

 (B)

 (i) emulsifying a reaction mixture into a continuous aqueous phase, in particular water, which comprises at least one stabilizer, in particular at least one surfactant, the reaction mixture comprising, based on the total weight of the reaction mixture:

 (a) 10.0 to 99.0 wt .-% of a monomer mixture, which comprises based on the total weight of the monomer mixture:

 (a1) 2.5 to 19.0 wt .-%, in particular 5.0 to 12.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid monomer;

(a2) 76.0 to 97.5 wt .-%, in particular 85.0 to 95.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid Ci-io-alkyl ester monomer; (a3) 0.0 to 5.0 wt .-%, in particular 0.0 to 3.0 wt .-%, of at least one monomer which carries at least two ethylenically unsaturated groups, preferably a divinylbenzene or a di- or triester of a C2-C10 polyols with ethylenically unsaturated C3-Cs-carboxylic acids, in particular a di- or triester of a C2-C10-alkanediol or -triol with ethylenically unsaturated C3-Cs-carboxylic acids,

 (b) 1, 0 to 70.0 wt .-%, preferably 1, 0 to 30.0 wt .-% magnetic nanoparticles whose surface is preferably hydrophobicized, wherein the magnetic nanoparticles preferably the polyaddition reaction of compounds with isocyanate groups and Catalyze NCO-reactive groups to form polyurethanes; and

 (c) optionally from 0.0 to 70.0% by weight of at least one polymerization catalyst or initiator, preferably a catalyst containing the polyaddition reaction of

 Compounds with isocyanate groups and NCO-reactive groups catalyzed to polyurethanes; and

(d) optionally, 0.0 to 89.0% by weight of at least one hydrophobic releasing agent, said releasing agent preferably having a Hansen parameter 5t of less than 20 MPa '²; and

 (e) optionally, from 0.0 to 10.0% by weight of at least one ultrahydrophobic compound other than the release agent, preferably an optionally fluorinated C12-28 hydrocarbon, more preferably a C14-26 alkane;

 (ii) optionally homogenizing the emulsion of step (i); and

 (iii) polymerizing the monomers.

A further aspect is directed to the nanocapsules obtainable by the methods described above and their use for catalyzing polymerization reactions, in particular of polyurethanes.

Yet another aspect relates to agents and compositions containing the nanocapsules of the invention.

"At least one" as used herein means 1 or more, ie 1, 2, 3, 4, 5, 6, 7, 8, 9 or more. With respect to an ingredient, the indication refers to the kind of the ingredient and not to the absolute number of molecules. "At least one release agent" thus means, for example, at least one type of release agent, ie that kind of

Release agent or a mixture of several different release agents can be used. The term "weight information" refers to all compounds of the specified type contained in the composition / mixture, ie Composition beyond the specified amount of the corresponding compounds addition no further compounds of this kind.

All percentages given in connection with the compositions described herein, unless explicitly stated otherwise, relate to% by weight, in each case based on the mixture in question.

"Emulsion" or "miniemulsion" as used herein refers to an oil-in-water (O / W) emulsion in which the emulsified phase is in the form of droplets or particles, preferably of approximately spherical shape, in the continuous water phase available. In this case, the droplets / particles of a miniemulsion have an average size, with an approximately spherical shape an average diameter, in the size range of 50 to 500 nm, preferably 100 to 300 nm.

The term "nanocapsule" as used herein refers to the emulsified polymerized particles prepared by the methods described herein, having the aforesaid average size in the range of 50 to 500 nm, preferably 100 to 300 nm Values refer to the z-average ("z-average") from dynamic light scattering according to ISO 22412: 2008. In the context of the present invention, the term "nanocapsule" may refer to both a core-shell nanostructure in which a shell of polymers includes the magnetic nanoparticles as well as the remaining constituents of the present invention, as well as a matrix-like nanostructure In both cases, the magnetic nanoparticles as well as the remaining constituents of the respective nanostructure as defined herein are referred to as "encapsulated".

In various embodiments of the invention, the monomers for the capsule shell are chosen such that the copolymer obtainable from the monomer mixture has a theoretical glass transition temperature T _g of 95 ° C. or more, in particular 100 ° C. or more, more preferably 105 °, calculated analogously to the Fox equation C or and more. In particular, when a volatile blowing agent, ie having a boiling point up to 200 ° C, is used, these T _g values are preferred in order to ensure a sufficient barrier effect of the capsule shell.

"Glass transition temperature" or " _Tg " as used herein refers to the temperature at which a given polymer transitions from a solidified glassy state to a rubbery state and awakens polymer segment mobility. It is related to the Stiffness and the free volume of a polymer and can be experimentally known

Procedures such as the Dynamic Mechanical Thermal Analysis (DMTA) or the Differential Scanning Calorimeter (DSC). Both methods are known in the art. It should be noted that, depending on the measuring method and the used

Measuring conditions or the thermal history of the polymer sample different glass transition temperatures can be obtained for an identical polymer system.

In fact, the indication of a defined temperature already has a certain inaccuracy, since the glass transition typically takes place within a temperature range. In addition, glass transition temperatures of nanocapsules are experimentally difficult to access and not every determination method is suitable. The herein stated

Glass transition temperatures are therefore calculated theoretically analogous to the Fox equation, unless stated otherwise. In the following, the correspondingly calculated values of the glass transition temperature are sometimes also referred to as "estimated".

Exceeding the glass transition temperature, the capsule shell is widened more and more by increasing the mobility of the polymer and can thereby gradually lose at least part of their barrier effect, ie become more permeable to the encapsulated content. The thermolatency can thus be effected at least in part via the T _{g of} the shell polymer and the raising of the temperature over the T _g .

The Fox equation (see TG Fox, Bull. Am. Phys Soc., 1 (1956) p. 123) states that the reciprocal glass transition temperature of a copolymer is calculated using the proportions by weight of the comonomers used and the glass transition temperatures of the corresponding homopolymers of the comonomers leaves:

In the general equation, n represents the number of monomers used, i the running number via the monomers used, w, the mass fraction of the respective monomer i (in% by weight) and T the respective glass transition temperature of the homopolymer from the respective monomers i in K ( Kelvin).

The values for the glass transition temperatures of the corresponding homopolymers can also be taken from relevant reference works (see J. Brandrup, EH Immergut, EA Grulke, "Polymer Handbook", 4th edition, Wiley, 2003). relevant corresponding glass transition temperatures of Homopolymers listed below: methyl acrylate (MA), T _g = 10 ° C methyl methacrylate (MMA), T _g = 105 ° C; Ethyl acrylate (EA), T _g = -24 ° C; Ethyl methacrylate (EMA), T _g = 65 ° C; n-butyl acrylate (BA), T _g = -54 ° C; n-butyl methacrylate (BMA), T _g = 20 ° C; n-hexyl acrylate (HA), T _g = 57 ° C; n-hexyl methacrylate (HMA), T _g = -5 ° C; Styrene (S), T _g = 100 ° C; Cyclohexyl acrylate (CHA), _Tg = 19 ° C;

Cyclohexyl methacrylate (CHMA), T _g = 92 ° C; 2-ethylhexyl acrylate (EHA), T _g = -50 ° C;

2-ethylhexyl methacrylate (EHMA), T _g = -10 ° C; Isobornyl acrylate (IBOA), T _g = 94 ° C;

Isobornyl methacrylate (IBOMA), T _g = 1 10 ° C; Acrylic acid (AA), T _g = 105 ° C; Methacrylic acid (MAA), T _g = 228 ° C.

It should be noted that in the present case when using multiple vinylically or ethylenically unsaturated, radically polymerizable monomers (so-called

"Branching" or "crosslinker") these are not included in the calculation of the glass transition temperature. The values calculated by means of the listed equation as described above are herein referred to as "theoretically calculated analogous to the Fox equation" or

"Estimated".

The process described herein is based on a polymerization-induced phase separation determined by the interaction with water and in which a hydrophobic phase separation occurs

Compound is enclosed in a slightly less hydrophobic polymer shell. The formation of nanocapsules by phase separation is based on the poor solubility of a polymer in a solution. In this case, for example, an organic liquid to be included, serve as a solvent for the monomers, wherein the same liquid after the

Polymerization can no longer act as a solvent for the polymer.

In various embodiments of the invention, the Hansen parameter is des

Polymer of the capsule shell 15-19, preferably 16-18, more preferably about 17, the Hansen parameter ö _P 10-14, preferably 1 1-13, more preferably about 12, and the Hansen parameter öh 13-17, preferably 14 -16, more preferably about 15, especially 15.3. The Hansen parameter ot is preferably 23-28, preferably 24-27, more preferably 25-26. The Hansen parameter is always given herein in unit MPa ' ² unless otherwise specified.

The Hansen parameter is a widely used parameter in polymer chemistry for comparing the solubility or miscibility of various substances. This parameter was developed by Charles M. Hansen to predict the solubility of one material in another. Here, the cohesive energy of a liquid is considered, which can be divided into at least three different forces or interactions: (a) dispersion forces between the molecules öd (b) Dipolar intermolecular forces between the molecules δ _Ρ and (c) hydrogen bonds between the molecules 5h. These three parameters can be combined into a parameter 5t according to the formula 5t ² = öd ² + δ _Ρ ² + 5h ² . The more similar the Hansen parameter of different materials, the better they are miscible. Unless otherwise indicated, the Hansen parameter values given herein refer to the values as reported by Hansen in Hansen Solubility Parameters. A User's Handbook, Vol. 2, Taylor & Francis Group, Boca Raton, 2007, given or calculated, especially at room temperature (20 ° C). The determination of the Hansen parameters of

Capsule shell takes place in particular as in Angew. Chem. Int. Ed. 2015, 54, 327-330.

For a mixture of solvents, the Hansen solubility parameters can be calculated with the volume fraction of the two solvents. The following equation can be used to calculate the parameter δ _χ for two solvents S1 and S2, where x = h, d or p:

In a 3D plot, the three solubility parameters for a solvent represent the

Coordinates of a single point in three-dimensional space. For polymers P, the three parameters represent the coordinates of the center of a "solubility sphere" of radius Ro

(Sphere of interaction). This sphere represents the region in which the polymer is soluble (for linear polymers) or where it can be swelled (in the case of a crosslinked polymer network).

The Hansen solubility parameters can thus be determined by swelling experiments in solvents of known Hansen parameters. Is the polymer soluble or is it in the

Solvent swelled, the Hansen parameter of the solvent is within the Löslichkeitkkeitskugel of the polymer. For two substances, for example the solvent S and the polymer P, the "distance" R _a between the solubility parameters of these components can be calculated with the following equation (see CM Hansen, Hansen Solubility, Parameters A User ^'s Handbook, Vol. Taylor & Francis Group, Boca Raton, 2007):

{Raf = 4 (δ _dS - 5dpf + (δ _P s - 5 _pP f + {5 _hS - Std

High affinity or solubility presupposes that R _{a is} less than R ₀ . In order to obtain a phase separation during the polymerization and thus core-shell structure, it is preferred that the polymer be poorly soluble in the respective one

Be given nuclear material. Consequently, the determination of Hansen solubility parameters of the polymer used can be used to ensure good solubility of the polymer in the

To avoid nuclear material.

With the radius of the solubility sphere Ro and the values for R _{a of} the core materials, the so-called relative energy difference (RED) of the considered system can be calculated:

RED = RJRo

A RED value of 0 is found for no energy difference of the compared materials. A value less than one indicates high affinity, and a value greater than one indicates low affinity between the materials. In other words, a RED value less than or equal to one indicates solubility, a RED value greater than one indicates incompatibility and thus no mixture. Accordingly, preferably, a high RED value should result in comparing the core and shell substances to achieve phase separation during polymerization.

In various embodiments of the invention, the compound to be encapsulated or the mixture of compounds to be encapsulated satisfies the above relationship such that RED is> 1. In particular, R _a / Ro> 1, with Ro = 8-15, especially 10-13, preferably 1-1-12, more preferably about 1.1-3, most preferably 1.1-3. Ro and R _a are always given herein in unit MPa ' ² unless otherwise specified.

In the methods described herein, the mixture to be encapsulated, i. the magnetic nanoparticles and optionally the polymerization catalyst, the release agent, in particular blowing agent, and / or the ultrahydrophobic compound, under homogenization and / or polymerization, preferably at room temperature (20 ° C) and atmospheric pressure (1013 mbar), preferably liquid "As used in this context, includes all flowable under the conditions mentioned substances, flowable homogeneous

Mixtures of substances and flowable heterogeneous mixtures, including emulsions, dispersions or suspensions, with a. In various embodiments, it may be advantageous if the monomers of the

Monomer mixture in the mixture to be encapsulated under the emulsification / homogenization conditions are at least partially soluble. In different

According to embodiments, the monomer mixture can therefore be used as a solution of the monomers in at least one hydrophobic compound, for example the release agent or propellant. Although not preferred according to the invention may be encapsulated

Compound mixture and the monomers are also dissolved in an organic solvent and the resulting solution in step (i) emulsified / dispersed in the continuous phase.

The magnetic nanoparticles are particulate aggregates, which in the

Substantially consist of a magnetic metal or a magnetic derivative thereof. The magnetic metal can be selected from the group consisting of Sc, V, Cr, Fe, Co, Ni, Y, Zr, Mo, u, Mn, Pd, La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, He, Tm, Lu, Ta, Os, Ir, Pt, Au, Eu, Sm, Yb. AI. Th and U are selected. However, it may also be a combination of the aforementioned metals. It is preferably Fe, Ni, La, Y. Mn or a combination of the aforementioned. Alternatively, it may also be a semi-metal, such as boron (B) act. The term "derivative ^" in this context refers to an alloy of one of the abovementioned metals with one or more other elements or an oxide or carbide of one of the abovementioned elements. In various embodiments, the magnetic nanoparticles are capable of catalyzing or initiating the polymerization reaction of certain monomers or prepolymers, in particular the polyaddition reaction of compounds having isocyanate groups and NCO-reactive groups to give polyurethanes. In different

Embodiments, the magnetic nanoparticles are magnetite nanoparticles.

In various embodiments, the magnetic nanoparticles have an average size, in an approximately spherical shape an average diameter, in the size range of> 1 nm preferably> 2 nm and / or <50 nm, preferably <25 nm, in particular <15 nm, that is for example> 1 nm and <50 nm, preferably> 1 nm and <25 nm, particularly preferably> 2 nm and <15 nm. The sizes of the particles can be determined, for example, by means of

Determine transmission electron microscopy (TEM) and a statistical evaluation

(for example, according to Pyrz et al., Langmuir, 2008, 24 (20), 1 1350-1 1360).

According to various particularly preferred embodiments, the magnetic nanoparticles of the present invention are superparamagnetic. In various embodiments, the magnetic nanoparticles of the present invention have a magnetization with values in the range of> 60 emu / g, preferably> 70 emu / g, especially> 75 emu / g. For example, in various embodiments, the magnetic nanoparticles have a magnetization of at least 77 emu / g. The

Magnetization can be determined, for example, by means of a vibrating magnetometer (VSM) (Lu et al., Angew Chem Chem International Ed., 2007, 46, 1222-1244, McCollam et al., Review of Scientific Instruments 201, 1, 82, 053909, Foner , J. Appl. Phys., 1996, 79 (8), 4740-4745).

In order for the magnetic nanocapsules and / or the release agent to be particularly effectively encapsulated, it is advantageous that they be hydrophobic so that they do not interact with the polymer formed from the monomers to unduly swell under synthetic and storage conditions thereby become more permeable.

It is therefore preferred in various embodiments that the surface of the magnetic nanoparticles be modified such that they are hydrophobic. In the context of the present invention, the hydrophobization of the surface of the magnetic

Nanoparticles by the binding of ligands to the surface of the particles. In principle, suitable for this purpose are all types of ligands capable of binding to the surface of the magnetic nanoparticles and at the same time a hydrophobic shell on their

Surface to build. Suitable ligands are known to the person skilled in the art. Without as

However, in this context, for example, thiols, phosphonates, phosphates, acetylacetonates, fatty acids and the like are mentioned as being limiting. It is preferred that the surface of the magnetic nanoparticles according to the present invention is modified with a ligand having an HLB value of less than 10 as determined by the method described by Griffin (HLB Classification of surface active agents, J. Soc Cosmet. Chem. 1, 1949). In particular, it is preferred that the surface of the magnetic nanoparticles according to the present invention is modified with a ligand having a Hansen parameter 5t of less than 20, preferably less than 19, in particular less than 15; and / or has a Hansen parameter 5h of less than 12, preferably less than 10, more preferably less than 6, in particular less than 2. For example, in various embodiments, the ligand may have a Hansen parameter 5h of zero. In various embodiments of the invention, the ligand satisfies the above relationship between Hansen parameters of the shell polymer and Hansen parameters of the ligand or mixture of ligand and release agent, and, if present,

Catalyst / initiator such that RED> 1. In particular, R _a / Ro> 1, with Ro = 8-15, in particular 10-13, preferably 1-1-12, even more preferably about 1.1-3, most preferably 1.1-3. In the context of In the present invention, such modified nanoparticles are referred to as hydrophobized nanoparticles.

In various embodiments, the surface of the magnetic nanoparticles is modified with at least one saturated or unsaturated fatty acid having from 1 to 30 carbon atoms. Exemplary in this connection are palmitoleic acid, oleic acid,

Petroselinic acid, vaccenic acid, gadoleic acid, iscosenoic acid, cateloic acid, erucic acid,

Linoleic acid, α-linolenic acid, γ-linolenic acid, calendic acid, punicic acid, α-elaeostearic acid and β-elaeostearic acid. In particular, it is preferred that the surface is modified with a saturated or unsaturated fatty acid having a Hansen parameter 5t of less than 20, preferably less than 19, especially less than 15; and / or has a Hansen parameter 5h of less than 12, preferably less than 10, more preferably less than 6, in particular less than 2. In various embodiments of the invention, the fatty acid satisfies the above relationship between Hansen parameters of the shell polymer and Hansen parameters of the fatty acid or mixture of fatty acid and release agent and, if present, catalyst / initiator such that RED is> 1. In particular, R _a / Ro> 1, with Ro = 8-15, especially 10-13, preferably 1-1-12, more preferably about 1.1-3, most preferably 1.1-3. Methods of making such modified magnetic nanoparticles are known in the art. (Latham, AH, ME Williams, Accounts of Chemical Research, 2008, 41 (3), 41 1-420; Bannwarth, MB, et al., Angewandte Chemie International Edition, 2013, 52 (38), 10107-101 1 1 In various embodiments, the surface of the magnetic nanoparticles is modified with oleic acid.

In various embodiments, the nanocapsules according to the invention may, in addition to the magnetic nanoparticles, which catalyze or initiate the polymerization reaction of certain monomers or prepolymers, in particular the polyaddition reaction of

Compounds with isocyanate groups and NCO-reactive groups to polyurethanes, additionally comprise at least one further polymerization catalyst or initiator. According to these embodiments, it is preferred that the at least one further catalyst / initiator compound has a Hansen parameter 5t of less than 20, preferably less than 19, in particular less than 15; and / or has a Hansen parameter 5h of less than 12, preferably less than 10, more preferably less than 6, in particular less than 2. For example, in various embodiments, the at least one catalyst / initiator may have a Hansen parameter 5h of zero. In various embodiments of the invention, the catalyst / initiator compound, especially when used without a release agent, satisfies the above relationship between Hansen parameters of the shell polymer and Hansen's Parameters of the catalyst / initiator such that RED is> 1. In particular, R _a / Ro> 1, with Ro = 8-15, especially 10-13, preferably 1-1-12, more preferably about 1.1-3, most preferably 1.1-3.

It is further preferred that the hydrophobic compounds, i. the release agent, the catalyst / initiator and the ultrahydrophobic compound, not severely interfering

Side reaction in the radical polymerization (for example, by radical scavengers such as phenols) and with the monomers (for example, no Michael reaction) show. The hydrophobic compounds are therefore preferably inert under the conditions employed to the monomers and the reactants used in the polymerization (with the exception of deliberately used reactive release agents, which are described in more detail below). Preferably, the hydrophobic compounds described above have an HLB value less than 10, as determined by the method described by Griffin (Classification of surface active agents by HLB, J. Soc. Cosmet. Chem., 1, 1949). A compound to be encapsulated can be considered to be excessively disturbing in the polymerization if, even upon post-polymerization or post-polymerization (see description below), a total monomer conversion of 80%, preferably 90% and more preferably 95% is not exceeded. When

Determination method is for example HPLC

 (High performance liquid chromatography). In addition, ideally the (headspace) gas chromatography can serve as a determination method, which can also be used to determine the encapsulation efficiency. In addition, this method not only allows the quantitative determination of the release kinetics, but also the determination of the conversion of most monomers. In some cases not all used

Comonomers can be measured by chromatographic methods (difficult determination of the total monomer conversion), the quantitative determination of individual comonomers is sufficient, which make up cumulatively at least 50% of the total monomer composition. In this case, a compound to be encapsulated is considered to be excessively disturbing if the cumulative conversion of at least 50% of the monomers used is <80%, preferably <90% and particularly preferably <95%.

In various embodiments, the at least one additional catalyst or initiator is a compound that can also catalyze or initiate the polymerization reaction of certain monomers or prepolymers. It may be, for example, known olefin catalysts, including metallocenes and ligands / complex compounds containing, for example, lanthanides, actinides, titanium, chromium, vanadium, cobalt, nickel, zirconium and / or iron, organometallic compounds, such as organic compounds on tin, Bismuth, or Titanium base, metathesis catalysts (Schröck, Grubbs, molybdenum, ruthenium), or to organic compounds such as organic peroxides (such as those used as crosslinking peroxides under the trade names Perkadox® and Trigonox® by Akzo Nobel NV or Luperox® from Sigma Aldrich available) or tertiary amines, such as DABCO, DBU act. Preferred organometallic compounds are thiolates, for example

Mercaptide of tin. Also preferred are halls (bis (salicylidene) ethylenediamine) and its derivatives, as described, for example, in Komatsu et al. (2008) Warden (Komatsu (2008) "Thermally latent reaction of hemiacetal ester with epoxides catalyzed by recyclable polymeric catalyst of salen-zinc complex and polyurethane main chain." Journal of Polymer Science Part A: Polymer Chemistry 46 (1 1) : 3673-3681). Particular preference is given to catalysts for the synthesis of polyurethanes, for example organotin compounds, such as DBTL

(Dibutyltin dilaurate), which is not preferred for reasons of toxicity, and in particular Zinnneodekanoat (Tributylzinnneodekanoat). Other metal-containing catalysts are described, for example, in Schellekens et al. (Schellekens, Y., et al., (2014) "Tin-free catalysts for the production of aliphatic thermoplastic polyurethane." Green Chemistry 16 (9): 4401-4407). In addition, preference is given to those catalyst systems which have a high stability in water or hydrolytic stability. In various embodiments, the at least one additional catalyst or initiator is a compound that is not tin-based. Of the

Catalyst / initiator is also not a catalyst / initiator for the polymerization of the monomers forming the capsule shell, i. different from such a catalyst / initiator.

It is preferred, as already described above, that the at least one further catalyst / initiator compound is a hydrophobic compound, i. has a Hansen parameter as indicated above. In those embodiments where the catalyst / initiator is sufficiently compatible with the capsule shell at elevated temperature to penetrate it, the use of a release agent can be dispensed with. The release mechanism is then based on the one hand, that the nanocapsules depending on the

Glass transition temperature T _{g of} the copolymer are temperature-sensitive. Increasing the temperature leads to a higher mobility of the polymer chains in the shell and thereby to a widening of the polymer shell (increase in the free volume), which thereby becomes more permeable. On the other hand, then at elevated temperature and the catalyst / initiator has a softening effect on the capsule shell. However, it is preferred that the

Catalyst / initiator is used together with a release agent containing this

Mechanism supported or additionally acts as a propellant. Nanocapsules which according to the present invention do not comprise catalytically active magnetic nanoparticles preferably have at least one polymerization catalyst or initiator (b2). The at least one polymerization catalyst or initiator (b2) is preferably contained in the nanocapsules in particular if the nanocapsules do not comprise magnetite nanoparticles, for example no hydrophobized magnetite nanoparticles, for example no magnetite nanoparticles hydrophobized with oleic acid.

The release agent is selected in various embodiments such that the

Catalyst / initiator is sufficiently soluble therein. The solubility for liquid compounds is preferably 20 g / l at room temperature (20 ° C) or solid compound at a temperature corresponding to the melting temperature of the compound T _m + 20 ° C. The melting temperature can be determined according to the standard DIN EN ISO 1 1357-3: 2013-04 by means of DSC at a heating rate of 10 K / min. To determine the solubility, a Metrohm 662 photometer equipped with a probe can be used to determine the light transmittance. For the measurement, visible light (entire spectrum) is then guided via optical fibers to the probe, which is immersed in the liquid sample. The light is emitted from the probe tip, travels through the sample solution, is reflected by a mirror, and then directed to the detector via optical fibers. Before reaching the detector, an optical filter can be used to allow the selective measurement of a particular wavelength. For such measurements, a wavelength of 600 nm can be used. An Ahlborn Almemo Multimeter was used to digitally record the transmissivity (analog output of the photometer) and a light transmittance of ^ 98% (at the chosen wavelength) was assumed to be complete solubility. When using highly absorbent (colored) fabrics, the wavelength measurement range should be set so that the measurement is performed in a region of minimum excitation. In addition, in the case of a non-volatile catalyst in substantially lower boiling release agents, the solubility can be determined gravimetrically (dry weight of a saturated solution). Further quantitative methods, eg based on chromatography or spectroscopy, are known to the expert and / or can be borrowed from the literature.

The release agent is also hydrophobic. Preferably, therefore, the release agent has an HLB value of less than 10, as determined by the method described by Griffin (Griffin, W.C.: Classification of surface active agents by HLB, J. Soc. Cosmet. Chem. 1, 1949). Furthermore, it is preferred that the release agent has a Hansen parameter 5t of less than 20, more preferably less than 19, even more preferably less than 15; and / or a Hansen parameter 5h of less than 12, preferably less than 10, more preferably less than 6, in particular less than 2 has. For example, in various embodiments, the at least one release agent may have a Hansen parameter 5h of zero. In various embodiments of the invention, release agent satisfies the above relationship between Hansen parameters of the shell polymer and Hansen parameters of the release agent or mixture of release agent and catalyst / initiator such that RED is> 1. In particular, R _a / Ro> 1, with Ro = 8-15, especially 10-13, preferably 1-1-12, more preferably about 1.1-3, most preferably 1.1-3.

In various preferred embodiments, the release agent is below

Homogenization and / or polymerization conditions, preferably at room temperature (20 ° C) and atmospheric pressure (1013 mbar), liquid.

In various embodiments, the release agent may be a reactive release agent that is at least partially polymerized in the catalyst-mediated polymerization after the capsules are broken. Examples of suitable compounds include, but are not limited to, polyfunctional nucleophilic compounds such as hydroxyl group-containing compounds, particularly the various polyols including polyether polyols such as polypropylene glycol, polytetrahydrofuran, polyesters, and also polyamides and polydimethylsiloxane, as well as castor oil, cardanol derivatives, where no phenolic

Hydroxyl groups are present, and other long-chain hydrophobic polyols and monoalcohols and (hydrophobic) epoxy resins.

In various particularly preferred embodiments, the release agent is a hydrophobic blowing agent, preferably a hydrocarbon, having a boiling point of 50 to 200 ° C, preferably 60 to 150 ° C, more preferably 80 to 120 ° C. The stated boiling point refers to the boiling point under standard conditions, i. at normal pressure (1013 mbar). The blowing agent is in various embodiments a Ce-ιο hydrocarbon, preferably a Ce-10 alkane, in particular isooctane (2,2,4-trimethylpentane), or a mixture of the aforementioned compounds. The propellant is preferably liquid at standard conditions and may serve to dissolve the monomers and, optionally, the catalyst compound therein. The specified boiling points make it possible to break up the nanocapsules by heating to temperatures above these boiling points, since the propellant then evaporates and the increasing pressure causes the nanocapsules to burst open.

In the following, the invention will be described by reference to certain specific embodiments. However, it is not intended that the invention be limited to these embodiments is limited but can be easily adjusted by using other monomers, stabilizers / surfactants and initiators. Incidentally, this also applies to the explicitly mentioned and exemplarily tested release / propellants and

Catalysts / initiators. Such embodiments are also within the scope of the invention.

In a first step of the process according to the invention, a stabilized emulsion is prepared. The emulsion contains the monomer mixture described above and at least one stabilizer, in particular a surfactant, the magnetic nanoparticles, optionally the

Release agent, optionally at least one further catalyst / initiator substance and optionally one or more ultrahydrophobic compounds in the form of an emulsion in an aqueous solvent. The aqueous solvent contains as main component (more than 50,

in particular more than 80% by volume) of water or may consist entirely of water. In various embodiments, the aqueous solvent may contain one or more nonaqueous solvents, for example selected from monohydric or polyhydric alcohols, alkanolamines or glycol ethers, provided that they are miscible with water in the given concentration ranges.

These additional solvents are preferably selected from ethanol, n- or isopropanol, butanol, glycol, propanediol or butanediol, glycerol, diglycol, propyl or butyl diglycol, hexylene glycol, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether .

Propylene glycol methyl, ethyl or propyl ether, dipropylene glycol monomethyl or ethyl ether, diisopropylene glycol monomethyl or ethyl ether, methoxy, ethoxy or butoxy triglycol, 1-butoxyethoxy-2-propanol, 3-methyl-3-methoxybutanol, propylene glycol t- butyl ether and

Mixtures thereof. In the aqueous solvent, such solvents can be used in amounts of between 0.5 and 35% by weight, but preferably less than 30% by weight and in particular less than 25% by weight.

The monomers used in the processes described are in particular ethylenically unsaturated carboxylic acids and their alkyl esters.

In various embodiments, the at least one monoethylenically unsaturated C3-C5 carboxylic acid monomer is selected from methacrylic acid (MAA), acrylic acid (AA),

Fumaric acid, methylmaleic acid, maleic acid, itaconic acid or mixtures of two or more thereof. Particularly preferred are methacrylic acid (MAA), acrylic acid (AA) or mixtures thereof. Most preferred is methacrylic acid. These are, based on the monomer mixture, in particular in amounts of 2.5 to 19 wt .-%, preferably 5 to 12 wt .-%.

In various embodiments, the at least one monoethylenically unsaturated C3-5-carboxylic acid Ci-io-alkyl ester monomer is an acrylic acid or methacrylic acid alkyl ester or a mixture thereof. Preference is given to methacrylic acid-C 1 -5-alkyl ester monomers, in particular methyl methacrylate (MMA), n-butyl methacrylate (BMA) or a mixture thereof. Very particular preference is given to a mixture of methyl methacrylate and

Methacrylic acid n-butyl ester, in particular in a weight ratio of 3.5: 1 to 16: 1, preferably 6: 1 to 16: 1. The alkyl radicals may generally be straight-chain or branched, unless specified specifically. These monomers are, based on the monomer mixture, in particular in amounts of 76 to 97.5 wt .-%, preferably 85 to 95 wt .-%.

The monomer bearing at least two ethylenically unsaturated groups may generally be any compound bearing two ethylenically unsaturated groups, for example two vinyl groups. Examples of suitable compounds include, but are not limited to, divinyl aromatics, such as, in particular, divinylbenzenes or multiple esters of a polyol with ethylenically unsaturated carboxylic acids, especially di- or triesters of a C 2 -C 10 polyol with ethylenically unsaturated C 3 -C 8 carboxylic acids. The latter are in various embodiments diester of methacrylic acid or acrylic acid with 1, 3-propanediol, 1, 4-butanediol or 1, 5-pentanediol, especially a methacrylic acid ester of 1, 4-butanediol.

Preference is given to di- and triacrylates or di- and trimethacrylates of polyhydric alcohols.

The abovementioned compounds having at least two ethylenically unsaturated groups serve as crosslinkers in the monomer mixtures. The crosslinkers are based on the

Monomer mixture in amounts of up to 0 to 5 wt .-%, preferably up to 4.5 wt .-%, more preferably used to 4 wt .-%.

In various embodiments of the invention, with the monomer mixture, the magnetic nanoparticles, optionally the at least one further catalyst / initiator substance and optionally the release agent in step (i), an ultrahydrophobic compound, in particular a C12-28 hydrocarbon, more preferably a Cu-26 alkane , such as hexadecane, are emulsified in the continuous phase. Also, Cu-26 monoalcohols or monocarboxylic acids or fluorinated derivatives of the aforementioned may be suitable. The catalyst can be present, for example, dissolved in these. In various embodiments, the ultrahydrophobic compound may also incorporate a polymerizable into the capsule shell or matrix C12-28 hydrocarbyl, possible compounds include, but are not limited to, lauryl (meth) acrylate (LA or LMA), tetradecyl (meth) acrylate (TDA or TDMA),

Hexadecyl (meth) acrylate (HDA or HDMA), octadecyl (meth) acrylate (ODA or ODMA),

Eicosanyl (meth) acrylate, behenyl (meth) acrylate and mixtures thereof. Be such

used ultra hydrophobic polymerizable compounds, these are not in the

Calculation of the glass transition temperature analogous to the Fox equation (see above) included. These ultrahydrophobic compounds are compounds other than the release agent, typically those which have a boiling point> 200 ° C under standard conditions. "Ultra-hydrophobic" as used herein in connection with the compounds described above means that the corresponding compound has a solubility in water at 60 ° C of less than 0.001% by weight as determined by the method described by Chai et al

Eng. Chem. Res. 2005, 44, 5256-5258).

In various further embodiments of the invention, it is also possible with the monomer mixture in step (i) to emulsify further polymerizable compounds, for example vinylically unsaturated monomers, in particular styrene, into the continuous phase. When such additional polymerizable compounds are used, the amount is not more than 50% by weight based on the monomer mixture as defined above.

In certain preferred embodiments, the monomer mixture used is a mixture of:

 (a) 2.5 to 19.0% by weight, especially 5.0 to 12.0% by weight of methacrylic acid (MAA);

(b) 70.0 to 80.0 weight percent, especially 72.5 to 80.0 weight percent, methyl methacrylate (MMA);

(c) 6.0 to 17.5 wt%, especially 5.0 to 12.5 wt%, n-butyl methacrylate (BMA); and

 (D) 0.0 to 5.0 wt .-%, in particular 0.5 to 3 wt .-%, 1, 4-butanediol dimethacrylate (BDDMA) used.

Such mixtures give a polymer having the desired glass transition temperature (calculated as described above analogous to the Fox equation), for example of> 95 ° C., in particular> 100 ° C. At the same time, these monomer mixtures are hydrophobic enough to give stable miniemulsion droplets.

In various embodiments, the emulsion 1 prepared in step (i) of the process according to the invention contains from 0 to 70.0% by weight, preferably from 1.0 to 30.0% by weight, more preferably from 0.1 to 15% by weight. % magnetic nanoparticles as defined above; From 0.0 to 70.0% by weight, preferably from 1.0 to 70.0% by weight, more preferably from 5.0 to 70.0% by weight of at least one A polymerization catalyst or initiator as defined above; 0.0 to 89.0 wt.%, Preferably 1.0 to 89.0 wt.%, More preferably 5.0 to 89.0 wt.%, Particularly preferably 10.0 to 89.0 wt. -%, particularly preferably 20.0 to 89.0 wt.%. at least one hydrophobic releasing agent as defined above; and from 0.0 to 10.0% by weight, preferably from 1.0 to 10.0% by weight, in particular from 5.0 to 10.0% by weight, of at least one ultrahydrophobic compound other than the release agent.

In step (i) and optionally step (ii) of the method, at least one stabilizer is further used. The term "stabilizer" as used herein refers to a class of

Molecules that can stabilize the droplets in an emulsion, i. Coagulation and

Can prevent coalescence. The stabilizer molecules can be attached to the surface of the droplets or interact with this. In addition, (polymerizable)

Stabilizers are used, which can react covalently with the monomers used. If polymerizable stabilizers are used, they are not included in the calculation of the glass transition temperature analogous to the Fox equation (see above). Stabilizers generally contain a hydrophilic and a hydrophobic portion, wherein the hydrophobic part interacts with the droplet and the hydrophilic part is oriented towards the solvent. The stabilizers may be, for example, surfactants and may carry an electrical charge. In particular, they may be anionic surfactants, for example

Sodium dodecyl sulfate (SDS).

Alternative stabilizers that can be used in the methods described herein are known to those skilled in the art and include, for example, other known surfactants as well as polymeric protective colloids, such as e.g. Polyvinyl alcohol (PVOH) or polyvinylpyrrolidone (PVP). By means of the stabilizers used, colloidally stable heterophasic systems can be prepared in the processes according to the invention in the emulsification and, if appropriate, homogenization step.

Accordingly, in some embodiments, the blends described herein may also contain other protective colloids, such as hydrophobically modified polyvinyl alcohols,

Cellulose derivatives or vinylpyrrolidone-based copolymers. A detailed

Description of such compounds can be found, for. B. in Houben-Weyl, Methods of Organic Chemistry, Vol. 14/1, Macromolecular substances, Georg-Thieme-Verlag, Stuttgart, 1961, pages 41 1-420.

The total amount of stabilizer / surfactant is typically up to 30% by weight, preferably 0.1 to 10% by weight, more preferably 0.2 to 6% by weight, based on the total amount of Monomers or, if separate emulsions are used in the preparation of the hydrophobized magnetic nanoparticles.

The stabilizer can be used in the form of an aqueous solution. This solution may be compositionally similar to the composition of the continuous phase as defined above.

In various embodiments of the present invention, the preparation of the magnetic nanohybrid particles according to the invention takes place via a combined

Mini emulsion / emulsion polymerization.

In one embodiment, the first reaction mixture (a) becomes in step (i) by emulsifying the above-described components (a1), (a2) and (a3) into one

continuous aqueous phase prepared. The emulsion is prepared by mixing the respective different ingredients, for example with an Ultra-Turrax.

The preparation of a second reaction mixture (b) takes place in a step (ii) analogously to step (i) with the constituents (b1), (b2), (b3) and (b4) described above.

The reaction mixtures or miniemulsions thus obtained, i. the first miniemulgierte reaction mixture from step (i) and the second miniemulgierte reaction mixture from step (ii) are then combined together in a step (iii). The combining of the two mini-emulsions can mean a direct mixing together of the two miniemulsions. However, the combining of the two miniemulsions can also be done via the preparation of another miniemulsion.

Alternatively, the preparation of the emulsion may also be accomplished by emulsifying the monomer mixture and all other ingredients, i. especially the components to be encapsulated, in a single step. The emulsion is in this case prepared by mixing the respective different constituents, for example with an Ultra-Turrax, and optionally subsequently

homogenized to produce a miniemulsion. The homogenization and thus the production of a miniemulsion is carried out by a high shear process, for example by means of a high pressure homogenizer, for example with an energy input in the range of 10 ³ to 10 ⁵ J per second per liter of emulsion and / or shear rates of at least 1,000,000 / s. Shear rates can be readily determined by one skilled in the art by known methods. The high shear process, as used herein, may be by any known method of dispersing or emulsifying in a high shear field. Examples of suitable

Processes can be found, for example, in DE 196 28 142 A1, page 5, lines 1-30, DE 196 28 143 A1, page 7, lines 30-58, and EP 0 401 565 A1.

In a subsequent step, the polymerization of the respective contained takes place

Monomers. The polymerization is carried out according to the present invention with a suitable polymerization process, in particular by means of radical polymerization. For this purpose, polymerization initiators can be used. Useful initiators include, for example, thermally activatable, radiation-activatable, such as UV initiators, or redox-activatable, and are preferably selected from radical initiators. Suitable free radical initiators are known and available and include organic azo or peroxy compounds. The initiators are preferably water-soluble. When polymerization is initiated by a water-soluble initiator, free radicals are generated in the aqueous phase and diffuse to the water / monomer interface to initiate polymerization in the droplets. Examples of suitable initiators include peroxodisulfates, such as

Potassium peroxodisulfate (KPS), but are not limited thereto.

The polymerization may be carried out at elevated temperature, for example at a temperature in the range of 10-90 ° C, preferably 20-80 ° C, more preferably 40-75 ° C and most preferably 60-75 ° C. The polymerization can take place over a period of 0.1 to 24 hours, preferably 0.5 to 12 hours, more preferably 2 to 6 hours.

In general, the polymerization takes place under conditions compatible with the encapsulated active substances.

The term "about" as used herein in reference to a numerical value refers to a variance of ± 20%, preferably ± 10%, more preferably ± 5% of the corresponding value. Thus, "about 70 ° C" means 70 ± 14, preferably 70 ± 7, more preferably 70 ± 3.5 ° C.

The amount of residual monomers can also be carried out chemically by post-polymerization, preferably by the use of redox initiators, such as those described in DE-A 44 35 423, DE-A 44 19 518 and DE-A 44 35 422 , Suitable oxidizers for post-polymerization include, without limitation: hydrogen peroxide, t-butyl hydroperoxide, cumene hydroperoxide, or alkoxy peroxosulfates. Suitable reducing agents include, without Restriction: sodium disulfite, sodium bisulfite, sodium dithionite,

Sodium hydroxymethanesulfite, formamidinesulfinic acid, acetone bisulfate, ascorbic acid and reducing saccharides; and water-soluble mercaptans such as mercaptoethanol. The post-polymerization with a redox initiator can be carried out in a temperature range of 10 to 100 ° C, especially 20 to 90 ° C. The redox agents may be added independently or continuously over a period of 10 minutes to 4 hours. In order to increase the effectiveness of the redox agents, soluble salts of metals having different valences, such as iron, copper or vanadium salts, may be added to the reaction mixture. Usually, complexing agents which keep the metal salts in solution under the reaction conditions are also added.

In order to control the molecular weight of the polymers, a chain length regulator can be used. Suitable compounds are known in the art and include, for example, various thiols, e.g. 1-Dodecanethiol. In different

Embodiments in particular use those chain length regulators which can be consumed (polymerized in) in a reaction to be catalysed by the magnetic nanohybrid particles according to the invention. The chain length regulators can be used in the necessary amounts to the chain length to the desired extent

check. Typical amounts are in the range of 0, 1 to 5 wt .-%, preferably about 0.3 to 2.0 wt .-%, more preferably about 0.5 to 1, 0 wt .-% based on the

Gesamtmonomermasse.

In a further aspect, the invention relates to the nanocapsules by means of herein

described method are available. These may, in various embodiments, include magnetic nanoparticles, optionally one or more release agents, especially blowing agents, optionally one or more additional catalysts / initiators, and optionally one or more ultra hydrophobic compounds. In particularly preferred embodiments, the magnetic nanoparticles with oleic acid are hydrophobized magnetite nanoparticles and the optional blowing agent is isooctane and the ultrahydrophobic compound is hexadecane.

The content of the nanocapsules of the invention can be released by increasing the temperature. On the one hand, this temperature - dependent release of the capsule contents can be induced by magnetically induced heating of the magnetic nanoparticles inside the

Nanocapsules done. In addition to the increase in mobility of the polymer chains in the shell or matrix above the T _g, either the barrier effect of the shell or matrix is weakened by increasing their compatibility with the encapsulated compounds swells and thereby widened or, in the event that a blowing agent is used, the polymer shell is broken and the contents released when the temperature rises above the boiling point of the blowing agent. In connection with the nanocapsules and because of interactions with the polymer, the release may also be necessary to select a temperature which is up to 50 ° C above the actual boiling point of the propellant.

The nanocapsules described herein may find application in the catalysis of a variety of processes, particularly polymerization processes. Nanocapsules which, according to the present invention, comprise exclusively the magnetic nanoparticles, in particular oleic acid hydrophobized magnetite nanoparticles, as catalytically active constituents, ie comprise no further catalyst / initiator compound, are particularly suitable for use in conjunction with polyurethanes which are polymerized in controlled manner in the application should. Accordingly, such nanocapsules as constituents of numerous

Compositions containing such polyurethanes can be used. These may, for example, be adhesives or polyurethane-based coating agents. It is also conceivable to use nanocapsules according to the present invention containing titanium-based catalysts for condensation reactions, for example of silanes or silane-containing polymers. Further fields of application are the polymerization of epoxides, benzoxazines and metathesis systems. Particularly preferred is the use in crosslinking systems, such as elastomers and especially duromers. Generally close the

Applications include adhesives, sealants, coatings and infusion resins.

The compositions containing the nanocapsules described herein thus further contain, in various embodiments, at least one polyisocyanate or NCO-functional prepolymer and at least one compound having at least two NCO-reactive groups, especially a polyol. The catalyst, i. The magnetic nanoparticles and / or additional catalyst / initiator compounds then, upon release, catalyze the reaction between the isocyanate (NCO) groups and the NCO-reactive groups, typically hydroxyl groups, which react in a polyaddition to form urethane groups. As a result, the polyurethane polymers are formed from the monomers or prepolymers. It goes without saying that prepolymers having NCO-reactive groups, for example OH-functional prepolymers, can be used in addition to or instead of the NCO-functional prepolymers described. When

Polyisocyanates and polyols can all be used in connection with the polyurethane synthesis commonly used compounds. Of course, in addition to the described nanocapsules, the compositions may also contain other conventional ingredients of such agents.

In principle, all embodiments disclosed in connection with the nanocapsules as well as the agents of the invention are also applicable to the described methods and uses, and vice versa. For example, it is understood that all of the specific nanocapsules described herein are applicable to the means and methods mentioned and can be used as described herein.

The following examples are given to illustrate the invention, but the invention is not limited thereto.

Examples

Materials: all monomers, methyl methacrylate (MMA, Merck,> 99% stab.), Butyl methacrylate (BMA, Merck,> 99% stab.), Methacrylic acid (MAA, Acros, 99.5% stab) and 1,4-butanediol dimethacrylate (BDDMA, Sigma Aldrich, 95%) were obtained as without further

Purification used. Sodium dodecyl sulfate (SDS, Lancaster, 99%), hexadecane (HD, Merck> 99%) and the initiator potassium peroxodisulfate (KPS, Merck, for analysis) were used as received. The matrix-forming monomers Desmodur Z4470 (trifunctional isocyanate, Bayer, 70% in butyl acetate) and castor oil (hydroxyl number = 158 mg KOH / g, VWR International) were used as received. Isooctane (IO,> 99.5%; Carl Roth) and dimethyl tin dineodecanoate (Fomrez UL-28, Momentive, 50% in acetone) were used as received. Deionized water was used for all experiments.

 Materials Magnetite nanoparticles: Iron (II) chloride tetrahydrate (Merck,> 99%), Iron (III) chloride hexahydrate (VWR,> 99), Ammonia sol. (25%, traveling)

Production of magnetic nanocapsules

Synthesis of magnetite nanoparticles

 12.01 g (60 mmol) of iron (II) chloride tetrahydrate and 24.36 g (90 mmol) of iron (III) chloride hexahydrate were placed in a 500 ml three-necked flask with stirrer and reflux condenser and dissolved in 100 ml of distilled water. Subsequently, 40 ml of a 25% ammonia solution were added dropwise at room temperature and with constant stirring. Finally, 4 g (14.2 mmol) of oleic acid were added and the reaction mixture heated to 70 ° C for 1 h. Subsequently, the temperature was increased to 1 10 ° C for 2 h. After the reaction time and cooling to room temperature, the black precipitate was separated from the matrix by means of a super magnet, washed with demineralized water and dried at 40 ° C in a vacuum oven overnight.

Representation of the magnetic nanocapsules by miniemulsion polymerization

 Magnetic nanocapsules with magnetite loading between 1% and 10% were prepared by a miniemulsion process. For the disperse phase of the miniemulsion, 4 g of a monomer mixture consisting of 3 g of MMA (75% by weight), 0.4 g of BMA (10.25% by weight), 0.4 g of MAA (10% by weight) and 0.1 g crosslinker (BDDMA, 2.5% by weight) with 250 mg HD dissolved in 2 g of the core material.

A solution of 22 g of distilled water and 23 mg of SDS was then added to the hydrophobic mixture and pre-emulsified for three minutes with an Ultraturax (16,000 rpm). homogenized. By injecting high shear forces with a Branson Sonifier 450-D with an inch tip for 120 s (10 s pulse, 5 s pause) was then under ice-cooling, the

Miniemulsion produced and placed in a 50 ml round bottom flask. After reaching the

Polymerization temperature (70 ° C), a solution of 80 mg KPS in 2 ml of water was added and polymerized with stirring for 5 h. The particle sizes of the emulsions produced are between 177 and 203 nm.

Table 1: Magnetite loading for miniemulsion polymerization

^* MOA = magnetite oleic acid; ^** 1 = wt% magnetite

Figure 1 shows the morphology of sample MOA 10 at different resolutions. The capsules have a very high uniformity, as well as a core-shell structure. Figure 1 b further shows that magnetite particles are present in the nanocapsules.

Representation of the magnetic nanocapsules by means of emulsion polymerization

For a miniemulsion A, 0.769 g of MMA, 0.103 g of BMA and 0.103 g of MAA were mixed with 0.0256 g of the crosslinker BDDMA with 0.03 g of hexadecane. To the hydrophobic mixture, a solution of 24 g of distilled water and 10 mg of SDS was then added and homogenized for three minutes with an Ultraturax (16000 rpm) for the pre-emulsification. By injecting high shear forces with a Branson Sonifier 450-D with a V _2- inch tip, the monomer-mine emulsion was then produced for 120 seconds (10 sec. Pulse, 5 sec. Pause) under ice-cooling.

For a miniemulsion B, the amounts of hydrophobized iron oxide nanoparticles indicated in Table 2 were dispersed in isooctane in an ultrasonic bath for 30 minutes and, depending on the sample, mixed with 0.769 g of Fomrez. Subsequently, a solution of 24 g of distilled water and 25 mg of SDS was added. The biphasic system was miniemulgiert with a Branson Sonifier 450-D with V ₂ inch tip for 180 s (10 s pulse, 5 s rest) with ice cooling.

Table 2: Magnetite loading for the emulsion polymerization

 Magnetite Isooctane Fomrez

[g] [g] [g] LMOA ^* F ^** 1 2 0.0769

HMOA ^*** F 2 1 0.0769

 LMOA 1 2 -

HMOA 2 1 -

^* LMOA = magnetic polymer / hybrid particles with low magnetite loading

^** F = Fomrez

^*** HMOA = magnetic polymer / hybrid particles with high magnetite loading

The two miniemulsions A and B prepared were placed in a 100 ml one-necked flask, stirred for 5 minutes at room temperature and treated with a solution of 0.5 g of distilled water and 20 mg of KPS. Finally, the mixture was heated to 80 ° C and polymerized with stirring for 8 h. The size of the particles, determined by dynamic light scattering, amounts to 109 m with a polydispersity index of 0.19 for LMOA F and to 87 nm for HMOA F with a distribution of 0.14. Figure 2 shows the morphology of the capsules thus prepared, where a-c are the low-magnetic-content capsules (LMOA F) and d-e are the high-particle particles

Magnetite content (HMOA F). The morphology of the LMOA capsules without catalyst is similar to that of the catalytic, magnetic nanocapsules LMOA F (Figure 4). The Magnetitanteil is sufficiently low, so that have formed uniform core-shell structures. The magnetite is distributed homogeneously in the polymer matrix as expected. The particle sizes are 104 nm with a polydispersity index of 0.19. The Hansen parameter δd of the polymer of the capsule shell is approximately 17 MPa ² , the Hansen parameter δ _{P is} approximately 12 MPa ² , and the Hansen parameter is approximately 15 , 3 MPa ¹ ' ² .

For thermal analysis of the magnetic nanocapsules with catalyst and high (HMOA F) and low (LMOA F) magnetite loading and the LMOA nanocapsules TGA measurements were performed and compared with the nanocapsules without magnetite particles. The nanocapsules without magnetite show a mass loss of about 21% at 120 ° C, which is due to the evaporation of the isooctane. For the magnetic nanocapsules, this loss of mass is not recognizable. The decomposition of organic material begins with LMOA F and HMOA F at approx. 150 ° C and with the nanocapsules without magnetite loading at approx. 300 ° C. As expected, the polymer content of the nanocapsules without magnetite loading is much higher than that of the magnetic nanocapsules. This is further illustrated by the comparison of residues, which are only 8% for nanocapsules without magnetite loading, 54% for LMOA F and 64% for HMOA F, due to the higher inorganic content in these samples. The residue of LMOA amounts to approx. 58%. The saturation magnetizations of the LMOA sample calculated from the hysteresis curve shown in Figure 5 are 48 emu / g and due to the presence of the polymer shell in comparison to the saturation magnetization of the pure magnetite nanoparticles slightly decreased.

Rheoloqiemessunqen

 The rheology measurements were carried out under isothermal conditions at 50 ° C. and 120 ° C. and the curing reaction of the polyurethane composite was monitored. Thermolatent capsules without magnetite in the matrix serve as a reference.

Magnetic nanocapsules containing catalyst

 1 g of castor oil (OH number = 158) was mixed with 0.1% by weight of Fomrez, based on the amount of castor oil used, and mixed with 0.9945 g of IPDI trimer (NCO number = 355) by default. For the LMOA F sample, the amount of lyophilized powder weighed into the castor oil is 28.12 mg and for the HMOA F particles is 41.12 mg.

The curing reaction was monitored at constant temperature by measuring the complex viscosity, as shown in Figure 4.

At 50 ° C, the samples with the non-magnetite nanocapsules and the LMOA F nanocapsules show a modest increase in viscosity over time. The final viscosity of the LMOA F is so low that processing of the components is still possible even after several hours under these conditions. Both samples show a nearly identical behavior. Although the catalyst concentration is the same in all three samples, the sample with HMOA F shows a completely different behavior. The final viscosity is two orders of magnitude higher, which could be due to the morphology of the particles. Due to the large amount of magnetite particles in the polymer no core-shell structures are formed, which is why the catalyst is not shielded by a barrier, but is distributed freely in the polymer. For this reason, it can more easily diffuse out of the polymer and catalyze the polyurethane reaction.

Subsequently, the temperature was raised to 120 ° C. The sample with the nanocapsules without magnetite has an induction phase of about 15 minutes before the curing reaction is abruptly catalyzed. In the sample with the LMOA F nanocapsules, the catalysis of the reaction also takes place abruptly, but the induction phase is significantly shorter with 10 minutes. In contrast, the HMOA F capsules do not even show an induction phase, but catalyze the reaction immediately. One reason for this could be catalytic properties of oleic acid be, whereby the curing reaction is additionally accelerated. Therefore, the possible catalysis by magnetite is considered in more detail below.

Magnetic nanocapsules without catalyst

 The measurements made for the further elucidation of catalysis are shown in Figure 6. The pure PU matrix serves as reference again. (Figure 6a). The

Magnetite concentration at this time amounts to 1% by weight of magnetite, based on the polyol, for all samples in order to ensure the comparability of the results.

1 g of castor oil (OH number = 158) was mixed with 1% by weight of magnetite, based on the amount of castor oil used, and mixed with 0.9945 g of IPDI trimer (NCO number = 355) as standard. The exact quantities of the catalysts used are shown in Table 3.

Table 3: Weights of the magnetic, catalytic nanocapsules in the polyol

Accordingly, 1% by weight of magnetite hydrophobized with oleic acid was first stirred into the castor oil and admixed with isocyanate. The curing reaction was monitored at 50 ° C as well as at 120 ° C (Figure 6b). At 50 ° C, the magnetite shows no catalytic activity and is therefore inactive. At 120 ° C, the reaction is accelerated directly from the beginning, which confirms the assumption that the functionalized magnetite also contributes to the catalysis of the reaction. The starting viscosity is much higher than in the matrix. Since it is not clear whether the iron oxide or the attached thereto oleic acid is responsible for the catalysis, non-functionalized magnetite was prepared and also as a catalyst for the

Hardening reaction used (Figure 6c). At 50 ° C, the magnetite shows no activity and even at 120 ° C no clear acceleration of the reaction can be seen. However, the compatibility of the inorganic magnetite with the organic matrix is very low, which is why the measurement varies greatly.

Figure 6d shows oleic acid as a reaction accelerator of curing. The oleic acid, in contrast to the previously used heterogeneous catalysts is a homogeneous catalyst. For the comparability of the samples, the concentration of oleic acid is the proportion attached to 1% by weight of magnetite. Again, no catalysis of the reaction takes place at 50 ° C. At 120 ° C, however, after an induction phase of about 20 minutes one abrupt catalysis of the reaction. Thus, the oleic acid contributes significantly to the acceleration of the reaction.

Finally, the magnetic nanocapsules LMOA embedded in the matrix were measured (Figure 6e), which also show no catalytic activity at 50 ° C, but catalyze the reaction at 120 ° C after an induction phase of about 1 1 minutes. Compared to pure, unencapsulated magnetite, catalysis does not take place step by step, but abruptly, which again shows that the encapsulation method is very good for a

thermolatent catalysis is suitable. The accelerating effect of the magnetic nanocapsules on the PU reaction seems to be mainly due to the oleic acid. However, the induction phase is 9 minutes shorter when using the LMOA capsules than with oleic acid catalysis. As expected, the oleic acid as a homogeneous catalyst would have to catalyze the reaction faster. The additional acceleration comes thus on the probability by the

Combination of magnetite and the organic acid, similar to the organotin catalyst Fomrez. However, the difference between molecular and particulate structures must always be taken into account, which makes direct comparability difficult.

Figure 1 shows the morphology of the magnetic nanocapsules containing 10% by weight.

Magnetite prepared via a miniemulsion in step (ii) of the process as described herein at various resolutions.

Figure 2 shows the morphology of magnetic nanocapsules containing the catalyst Fomrez with 15 wt .-% and 46 wt .-% magnetite (Fig. 2a), 2b), 2c)) or 64 wt .-% magnetite (Fig. 2d) , 2e), 2f)).

Figure 3 shows the morphology of the magnetic nanocapsules containing 58% by weight.

Magnetite (LMOA) at different resolutions.

Figure 4 shows the time-dependent measurement of complex viscosity matrix-forming

Monomers at a) 50 ° C and b) 120 ° C of nanocapsules without magnetic nanoparticles (Figure 4c); TLCN 1), magnetic nanocapsules containing 54 wt .-% magnetite and the catalyst Fomrez (Fig. 4d), LMOA F), and magnetic nanocapsules containing 64 wt .-% magnetite and the catalyst Fomrez (Fig. 4e), HMOA F) ,

Figure 5 shows a VSM measurement of magnetic nanoparticles containing 58 wt% magnetite (LMOA). Figure 6 shows the time-dependent measurement of the complex viscosity of matrix-forming monomers at 50 ° C and 120 ° C of a) the pure matrix (castor oil and IPDI trimer), b) the matrix and magnetite with oleic acid functionalization, c) the matrix and magnetite without

Oleic acid functionalization, d) the matrix and oleic acid, e) the matrix and LMOA.

Claims

claims

A process for the preparation of nanocapsules containing magnetic nanoparticles, characterized in that the process comprises:

 (A) (i) emulsifying a first reaction mixture (a) into a continuous aqueous phase, in particular water comprising at least one stabilizer, in particular at least one surfactant, the first reaction mixture, based on the total weight of the reaction mixture, from 10.0 to 99.0 wt .-% of a monomer mixture, wherein the monomer mixture, based on the total weight of the monomer mixture comprises:

 (a1) 2.5 to 19.0 wt .-%, in particular 5.0 to 12.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid monomer;

 (a2) 76.0 to 97.5 wt .-%, in particular 85.0 to 95.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid Ci-io-alkyl ester monomer; and

 (a3) 0.0 to 5.0 wt .-%, in particular 0.0 to 3.0 wt .-%, of at least one monomer which carries at least two ethylenically unsaturated groups, preferably a divinylbenzene or a di- or triester of a C2-C10 polyols with ethylenically unsaturated C3-Cs-carboxylic acids, in particular a di- or triester of a C2-C10-alkanediol or -triol with ethylenically unsaturated C3-Cs-carboxylic acids;

 (ii) emulsifying a second reaction mixture (b) into a continuous aqueous phase, in particular water, which comprises at least one stabilizer, in particular at least one surfactant, the second reaction mixture comprising, based on the total weight of the reaction mixture:

 (b1) 1.0 to 80.0% by weight, preferably 10 to 70% by weight, in particular 30 to 60% by weight, of magnetic nanoparticles whose surface is preferably hydrophobicized, wherein the magnetic nanoparticles preferably comprise the polyaddition reaction of

 Catalyze compounds with isocyanate groups and NCO-reactive groups to give polyurethanes; and

 (b2) optionally 0.0 to 70.0 wt .-% of at least one polymerization catalyst or initiator, preferably a catalyst of the polyaddition reaction of

 Compounds with isocyanate groups and NCO-reactive groups catalyzed to polyurethanes; and

(b3) optionally 0.0 to 89.0% by weight of at least one hydrophobic release agent, wherein the release agent preferably has a Hansen parameter 5t of less than 20 MPa '²; and (b4) optionally 0.0 to 10.0% by weight of at least one ultrahydrophobic compound other than the release agent, preferably an optionally fluorinated C12-28 hydrocarbon, more preferably a C14-26 alkane;

 (iii) combining the first reaction mixture of step (i) and the second

Reaction mixture from step (ii); and

 (iv) polymerizing the monomers;

or

(B)

 (i) emulsifying a reaction mixture into a continuous aqueous phase, in particular water, which comprises at least one stabilizer, in particular at least one surfactant, the reaction mixture comprising, based on the total weight of the reaction mixture:

 (A) 10.0 to 99.0 wt .-% of a monomer mixture, based on the

Total weight of the monomer mixture comprises:

 (a1) 2.5 to 19.0 wt .-%, in particular 5.0 to 12.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid monomer;

 (a2) 76.0 to 97.5 wt .-%, in particular 85.0 to 95.0 wt .-%, of at least one monoethylenically unsaturated C3-5-carboxylic acid Ci-io-alkyl ester monomer;

 (a3) 0.0 to 5.0 wt .-%, in particular 0.0 to 3.0 wt .-%, of at least one monomer which carries at least two ethylenically unsaturated groups, preferably a divinylbenzene or a di- or triester of a C2-C10 polyols with ethylenically unsaturated C3-Cs-carboxylic acids, in particular a di- or triester of a C2-C10-alkanediol or -triol with ethylenically unsaturated C3-Cs-carboxylic acids,

 (b) 1, 0 to 70.0 wt .-%, preferably 1, 0 to 30.0 wt .-% magnetic nanoparticles whose surface is preferably hydrophobicized, wherein the magnetic nanoparticles preferably the polyaddition reaction of compounds with isocyanate groups and Catalyze NCO-reactive groups to form polyurethanes; and

 (c) optionally from 0.0 to 70.0% by weight of at least one polymerization catalyst or initiator, preferably a catalyst containing the polyaddition reaction of

Compounds with isocyanate groups and NCO-reactive groups catalyzed to polyurethanes; and

(d) optionally, 0.0 to 89.0% by weight of at least one hydrophobic releasing agent, said releasing agent preferably having a Hansen parameter 5t of less than 20 MPa '²; and (e) optionally, from 0.0 to 10.0% by weight of at least one ultrahydrophobic compound other than the release agent, preferably an optionally fluorinated C12-28 hydrocarbon, more preferably a C14-26 alkane;

 (ii) optionally homogenizing the emulsion of step (i); and

 (iii) polymerizing the monomers.

2. Method according to claim 1, characterized in that the magnetic nanoparticles consist essentially of at least one magnetic metal or a magnetic derivative thereof selected from the group consisting of Sc, V, Cr, Fe, Co, Ni, Y, Zr, Mo, u, Mn, Pd, La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, Ta, Os, Ir, Pt, Au, Th, Eu, Sm, Yb, Al, U or a combination of the aforementioned, preferably of Co, Fe, Ni, La, Y, Mn or a combination of the aforementioned, in particular consist of magnetite.

3. The method according to claim 1 or 2, characterized in that the magnetic

 Nanoparticles, the average size of the magnetic nanoparticles in the size range of <50 nm, preferably <25 nm, in particular <15 nm.

4. The method according to any one of claims 1 to 3, characterized in that the surface of the magnetic nanoparticles is hydrophobized with at least one ligand, wherein the ligand

 (a) a Hansen parameter 5t of less than 20, preferably less than 19,

 especially less than 15; and or

 (b) has a Hansen parameter 5h of less than 12, preferably less than 10, more preferably less than 6, especially less than 2.

5. The method according to any one of claims 1 to 4, characterized in that the monomers are selected for the capsule shell such that the copolymer obtainable from the monomer mixture a calculated analogous to the Fox equation theoretical

Glass transition temperature T _g of 95 ° C or more, in particular 100 ° C or more, more preferably 105 ° C or more.

6. The method according to any one of claims 1 to 5, characterized in that the average size of the nanocapsules in the size range of 50 to 500 nm, more preferably 100 to 300 nm.

7. The method according to at least one of claims 1 to 6, characterized in that the at least one polymerization catalyst or initiator

(a) has a Hansen parameter 5t of less than 20 MPa ' ² , preferably less than 19 MPa ¹ ' ² , in particular less than 15 MPa '²; and or

(b) has a Hansen parameter 5h of less than 12 MPa ¹ ' ² , preferably less than 10 MPa ¹ ' ² , more preferably less than 6 MPa ¹ ' ² , especially less than 2 MPa ¹ ' ² .

8. The method according to at least one of claims 1 to 7, characterized in that the hydrophobic release agent

(a) has a Hansen parameter 5t of less than 19 MPa ¹ ' ² , in particular less than 15 MPa ¹ '²; and or

(b) a Hansen parameter 5h of less than 12 MPa ¹ ' ² , preferably less than 10 MPa ¹ ' ² , more preferably less than 6 MPa ¹ ' ² , especially less than 2

MPa ^{/ 2} has.

9. The method according to at least one of claims 1 to 8, characterized in that the Hansen parameter öd of the polymer of the capsule shell 15-19 MPa ¹ ' ² , preferably 16-18 MPa ¹ ' ² , more preferably about 17 MPa ¹ ' ^2nd , the Hansen parameter δ _Ρ 10-14 MPa ¹ ' ² , preferably 1 1 -13 MPa ¹ ' ² , more preferably about 12 MPa ¹ ' ² , the Hansen parameter 5h 13-17 MPa ¹ ' ² , preferably 14- 16 MPa ¹ ' ² , more preferably about 15 MPa ¹ ' ² , in particular 15.3 MPa ¹ ' ² , and the Hansen parameter 5t preferably 23-28 MPa ¹ ' ² , more preferably 24-27 MPa ¹ ' ² , more preferably 25-26 MPa ¹ ' ² .

10. The method according to claim 9, characterized in that the compound or mixture to be encapsulated and the polymer of the capsule shell satisfy the following relationship:

R _a / Ro> 1, where

{Raf = 4 (ÖdS - 5dpf + (ö _pS - 5 _pP f + {5 _hS - Öhpf,

S is the compound or compound mixture to be encapsulated and P is the polymer of the capsule shell, wherein Ro is 8-15 MPa ¹ ' ² , especially 10-13 MPa ¹ ' ² , preferably 1 1 -12 MPa ¹ ' ² , more preferably about 1 1, 3 MPa ¹ ' ² , most preferably 1 1, 3 MPa ¹ ' ² .

1 1. Process according to at least one of Claims 1 to 10, characterized in that (1) the at least one singly ethylenically unsaturated C 3 -C 5 -carboxylic acid monomer is selected from methacrylic acid (MAA), acrylic acid (AA), fumaric acid, Methylmaleic, maleic, itaconic or mixtures of two or more thereof, especially methacrylic acid (MAA), acrylic acid (AA) or mixtures thereof; and or

 (2) the at least one monoethylenically unsaturated C3-5-carboxylic acid Ci-io-alkyl ester monomer is an acrylic acid or methacrylic acid alkyl ester or mixtures thereof; and or

 (3) the at least one ethylenically unsaturated C3-5-carboxylic acid ci-alkyl ester monomer is a methacrylic acid Cd-alkyl ester monomer, in particular a

 Methyl methacrylate monomer, n-butyl methacrylate monomer or a mixture thereof, most preferably a mixture of

 Methyl methacrylate and n-butyl methacrylate in a weight ratio of 3.5: 1 to 16: 1, preferably 6: 1 to 16: 1.

12. Nanocapsules obtainable according to one of claims 1 to 1 1.

13. A composition containing the nanocapsules according to claim 12, as well as a

 polymerizable resin, preferably at least one polyisocyanate or NCO-functional prepolymer and at least one compound having at least two NCO-reactive groups, in particular a polyol.

14. The composition according to claim 13, characterized in that the

 Composition is an adhesive, sealant, infusion resin or coating agent.

15. Use of the nanocapsules according to claim 12 for the polymerization of a polymer resin, in particular of polyurethanes.