DE10139790A1 - Microcapsules, process for their preparation and their use - Google Patents

Abstract

The invention relates to a microcapsule consisting of a coating and a content, wherein said content includes at least one non water-soluble compound with at least two reactive functional groups X relative to the isocyanate groups or epoxide groups or carboxyl groups or activated carboxyl groups. The invention also relates to a method for the production of said microcapsules. The invention further relates to adhesives containing microcapsules, a method for gluing substrates and to the use of said microcapsules in adhesives.

Description

The present invention relates to a microcapsule consisting of a capsule shell and a capsule content, the capsule content being at least one non-water-soluble Compound with at least two against isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups reactive functional groups X has and processes for their preparation. Furthermore, the present concerns Invention Adhesives containing microcapsules, process for bonding Substrates and the use of such microcapsules in adhesives.

Surface coating agents, especially adhesives, often contain several Components that interact with each other after the application of the surface coating agent react to form covalent bonds and thus harden the Cause surface coating agent. The different components can for example in the surface coating agent in such a way that curing only takes place at higher temperatures, while at usual ambient temperatures such as those for example, when applying the surface coating agent, none Reaction between the components takes place. Such, usually as However, surface coating agents called 1K systems often require very high ones Temperatures to harden. However, this limits the use of such 1K systems to the extent that certain, in particular heat-sensitive substrates are not included such a surface coating agent can be processed.

In contrast, surface coating agents exist, which are separated from two existing components (so-called 2K systems) exist. These two Components are usually installed shortly before the planned use of the Surface coating agent mixed. While such 2K systems do Allow curing at ambient temperature or only slightly elevated temperatures, however, before use, they require a mixing process in which defined Weighing quantities of the two components mixed together as precisely as possible Need to become. In practice, however, such mixtures are often used required mixing ratios are not adhered to exactly, so that Performance of the surface coating with regard to optimal curing is deteriorating. In addition, such 2K systems usually have to be added shortly after mixing are already processed, otherwise the progressive hardening of the mixed components make further processing difficult or impossible. This is particularly disadvantageous when larger amounts of Surface coating agents are to be used. In this case Repeatedly, several small portions are prepared for use, what the effort involved in processing such systems is significantly increased.

In order to remedy these disadvantages, systems have been developed in the prior art described one of the two components of a 2K system in deactivated form contain.

For example, EP-A 0 193 068 describes a 1-component epoxy resin composition, which is an epoxy resin with an average of at least two epoxy groups per molecule and contains a powdered amino compound. The amino compound was with a Coating provided either by adhesion or by covalent bonding adheres to the powder particle between the coating and the powder particle. The coating is effected by applying a compound which has at least one isocyanate group, one Carboxyl group, an anhydride group or an acid chloride group.

EP-A 0 547 379 relates to an adhesive which contains a diamine and an isocyanate, wherein either the diamine or the isocyanate is enclosed in a microcapsule. However, the microcapsules used in the publication are very large. This limits for example the use of the microcapsules described for adhesive joints with a gap width below such a size value strongly. Farther sediment the described microcapsules easily, causing such microcapsules containing adhesive becomes inhomogeneous. This does not result in a bond reproducible or even fails.

In "The applied macromolecular chemistry 190 (1991), 81-98" are thermolabile Microcapsules described, which are produced by interfacial polycondensation. One of the condensation components has an azo function. The Microcapsules are filled with a dye and open when exposed to heat. The released dye can on appropriate documents, for example after the principle of thermal transfer printing. The described Microcapsules have diameters of about 1 to 3 µm, their capsule wall was but not made using a water emulsifiable polyisocyanate.

The microcapsule systems known to date from the prior art have in Various disadvantages with regard to use in adhesives. So be for example, especially in the field of film adhesive bonding, which is essentially flat even when bonding particularly thin foils Adhesive surface result. However, this is when using microcapsule systems whose Microcapsules have a diameter of more than about 20 microns, difficult to realize. Also the gluing of surfaces, the unevenness like gaps or Holes with a diameter in the µm range can be made with such Glue systems poorly, as they are required to harden the adhesive Microcapsules do not have such gaps or holes due to their large diameter can penetrate. However, this is how the one in such gaps or holes hardens Adhesive content does not run out or is too slow.

The microcapsules known from the prior art are correspondingly small Have diameters are usually for in terms of their complex manufacture Adhesive applications are poorly suited. Correspondingly lower to achieve Diameters for the microcapsules are necessary on a high process Speed of a corresponding disperser. Such dispersion systems are however, often too expensive for a large-scale application and have a high Maintenance effort.

The encapsulation processes usually described in the prior art The interfacial polymerization used has further disadvantages. Frequently form the encapsulated microcapsules with the aid of such methods after encapsulation Agglomerates that are difficult to separate, as an agglomerate with regard to the above described needs unacceptably large particle diameter.

So there was a need for microcapsules for use in adhesive systems, which have the smallest possible diameter but are produced with a as little effort as possible. There was also a need for Adhesives containing at least two components reactive with one another, one of which of the components distributed as a microcapsule in a matrix of the other component is present. There was also a need for a method of making such Microcapsules.

Accordingly, the object of the present invention was to provide such Microcapsules, in the provision of a process for the production of such Microcapsules, in the provision of an adhesive containing such microcapsules.

The objects on which the invention is based are achieved by microcapsules, Process for their preparation and by means of adhesives, as described in the text below are described.

A first object of the present invention is therefore a microcapsule with a Diameter from 0.1 to 20 µm, consisting of a capsule shell and a capsule content, wherein the capsule content contains at least one non-water-soluble compound two versus isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups reactive functional groups X, and the Capsule shell by reaction of functional groups X of the capsule content with an in Water-emulsifiable compound, which compared to the functional groups X des Has capsule contents reactive functional groups Z has arisen.

A connection is then considered "not" in the context of the present invention water soluble "means when their water solubility in demineralized water a pH of 6.5 and a temperature of 20 ° C less than about 0.5 g / l, is in particular less than about 0.1 g / l.

In the context of the present invention, a “microcapsule” is a structure understood, which has a capsule content and a capsule shell. Such "Microcapsule" preferably has one in the context of the present invention Diameter less than about 20 microns, for example less than 17 microns, less than 14 µm or less than 10 µm. In a preferred embodiment of the present invention have at least about 50%, preferably at least about 80 or at least about 95% of the microcapsules according to the invention have a diameter of less than about 10 µm. The specified diameters refer to Measured values for particle diameters as they are determined using conventional methods of particle diameters are available. Suitable measuring methods are, for example Screening process, light scattering, electron microscopy, light microscopy, Scanning electron microscopy or sedimentation methods. This definition does not stand opposed to two or more microcapsules forming an aggregate have gathered together. The decisive factor in the present case is the particle size individual microcapsules participating in the unit.

The term “molecular weight” in the context of the present text, insofar as it is applied to polymeric or oligomeric compounds, refers to the weight average molecular weight (M _W ), as determined by GPC under suitable conditions, for example based on a polystyrene standard can be.

The microcapsules according to the invention can essentially have any spatial shape exhibit. For example, spherical, square, cuboid, cylindrical or conical shapes. As part of a preferred Embodiment of the present invention, however, the microcapsules have an im essentially spherical spatial shape.

The microcapsules according to the invention have a first capsule content Embodiment of the present invention at least one compound with at least two versus isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl-reactive functional groups X.

The term "activated carboxyl groups" refers in the context of the present Text on functional groups of the structure -C (O) -Z, where Z is for a electron-withdrawing group (atom or group with -I effect). Appropriate activated carboxyl groups are known to the person skilled in the art. Examples of such activated Carboxyl groups are so-called active esters or acid chlorides.

Suitable functional groups X are, for example, OH, NH ₂ , NHR ¹ , SH or COOH groups, where R ^{1 is} a linear or branched, saturated or unsaturated alkyl radical having 1 to about 24 carbon atoms.

A compound suitable as capsule content in the context of the present invention can only have one type of functional group X, d. that is, all on one molecule the corresponding compound functional groups X are identical. It However, it is also possible in the context of the present invention that the capsule content contains a compound having two or more functional groups X, where at least two of the functional groups X of a compound are different. So it is possible, for example, in the context of the present invention as a capsule content Use compound that, for example, at least one OH group and at least has an NH group.

A microcapsule according to the invention can be used as capsule content within the scope of the present Invention have only one compound that carries a functional group X. It is However, the invention also provides that a microcapsule according to the invention as Capsule content contains two or more different compounds. such different connections can differ in number or type of functional Groups X or in the constitution carrying the functional group X or in both differ.

In the context of a preferred embodiment of the present invention, a Microcapsule according to the invention as capsule content 1, 2 or 3 different Compounds with a functional group X.

A compound suitable as capsule content can be used within the scope of the present invention have only two functional groups X. However, it is also possible that the Capsule content of a microcapsule according to the invention has a compound that more as two functional groups X, for example three, four or five functional groups X has. The number of functional groups X of such a compound can be be an integer, for example if the capsule content is only one type of Contains compounds with a functional group X. However, it is also possible that the number of functional groups X is a number between two even numbers, for example, 2.1, 2.5, 2.8 or the like. This is particularly the case if the capsule contains a mixture of two or more compounds with one contains different number of functional groups X. In such a case the capsule contents contain, for example, compounds that differ only in the number of distinguish functional groups X.

In the context of a preferred embodiment of the present invention, a Microcapsule according to the invention as capsule content on at least one compound that carries at least one amino group as functional group X.

Suitable amines are, for example, aliphatic amines such as ethylenediamine, Propylene diamine, butylene diamine, pentamethylene diamine, hexamethylene diamine, Heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, Undecamethylene diamine, dodecamethylene diamine and the higher homologues of these Compounds that result from the gradual extension of the carbon chain. In principle, the amino groups can accumulate in the compounds mentioned any carbon atoms. In a preferred embodiment However, the present invention uses amines of the aforementioned type as capsule contents used, which carry the amino groups terminally.

Also suitable as capsule content in the context of the present invention Compounds that have two or more amino groups. Suitable examples of such amines are diethylene triamine, triethylene tetramine, tetraethylene pentamine or Diethylaminopropylamine.

Aromatic amines such as. Are particularly suitable in the context of the present invention m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, Bisaminomethyldiphenylene methane, o-phenylenediamine, triaminobenzene, o-aminobenzylamine, 2,4-diaminotoluene, benzidine, 4,4'-diaminodiphenylmethane, p, p-bisaminomethylbiphenyl, p, p-bisaminomethyldiphenylene methane, m-phenylenediamine, p-phenylenediamine, 4-aminodiphenylamine, hydrazides such as adipic acid dihydrazide, succinic dihydrazide, sebacic dihydrazide, Terephthalaldihydrazide, dicyandiamide, imidazole compounds such as imidazole, 2-methylimidazole, 2-undecylimidazole, 4-methylimidazole, 2-phenylimidazole, 2-heptadecylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 2-ethylimidazole, 2-isopropylimidazole, 2-dodecylimidazole, 2-ethyl-4-methylimidazole and Imidazoline compounds such as 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline or 2-heptadecylimidazoline or a mixture of two or more of the above Amino compounds.

The following amines are also suitable as amines in the context of the present invention applicable: isophoronediamine, m-xylylenediamine, 2,2,4-trimethylhexamethylenediamine, 4,4'-trimethylene dipiperidine, 1,3-di (4-piperidyl) propane, 4,4-diaminodicyclohexylmethane, 1,4-diazabicyclo [2.2.2] octane (DABCO) and polymeric di- or polyamines such as Amino groups containing polyesters, polyurethanes or polyethers, especially those under the tradename Jeffamine® from Huntsman Corp. available amino groups bearing polyalkylene glycols.

In the context of a preferred embodiment of the present invention, the Capsule content 4-aminodiphenylamine, 4,4'-diaminodiphenylmethane, 4,4'-trimethylene dipiperidine, bis- (4-aminocyclohexyl) methane, 4,4'-methylenebis (2,6-diethylaniline), diamino-m- xylene, 1,4-diaminocyclohexane, 1,4-bis (aminomethyl) benzene, 1,12-diaminododecane, 1,8- Diaminooctane, 1,6-diaminohexane, diaminodiphenylethane, phenylenediamine-1,3, Phenylenediamine-1,4, dipropoxy-p-toluidine, diethoxy-p-toluidine, dicyandiamide, amines as they are for example as a commercial product "Metallon hardener" from Henkel, polymeric amines of the Jeffamin type, for example Jeffamin ED 2003, Jeffamin D 2000, Jeffamin D 3000 or Jeffamin D 5000, isophoronediamine, 3- (aminomethyl) benzylamine, 2,2-dimorpholinodiethyl ether, trimethyl-1,6-hexanediamine, bis- (2-aminoethylamine), Coconut fatty amine oxyethylates, oleyl amine oxyethylates, N, N-bisaminopropyl tallow fatty amine, Oleylpropylenediamine, dodecylpropylenediamine or tallow fat propylenediamine as described under the Trade names Genamin as products C020, O020, 3119, OLP100, LAP100D or TAP100D are available from Clariant, bis (aminocyclohexyl) methane or 2,2'- Dimethyl-4,4'-methylenebis (cyclohexylamine) or a mixture of two or more thereof.

Compounds bearing carboxyl groups, i. that is, as connections with at least two Carboxyl groups as functional groups X are suitable in the context of the present Invention in particular the water-insoluble di- or polycarboxylic acids. such Di- or polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic or heterocyclic or both. They can optionally be substituted, for example by alkyl groups, alkenyl groups, ether groups or halogens. As polycarboxylic acids Examples include adipic acid, suberic acid, azelaic acid, sebacic acid, isophthalic acid, Terephthalic acid, trimellitic acid, tetrachlorophthalic anhydride, dimer fatty acid or Trimer fatty acid or mixtures of two or more of them are suitable. If necessary the capsule content of a microcapsule according to the invention still in minor amounts monofunctional carboxylic acids, especially monofunctional fatty acids with 6 to 44 C atoms.

Within the scope of a further embodiment of the present invention, a Microcapsule according to the invention as capsule content also compounds with functional Have groups X whose water solubility is more than about 1 g / l, for example low molecular weight polyalcohols, low molecular weight polycarboxylic acids or corresponding low molecular weight water-soluble polyamines. In this case, such a connection however, in a matrix of a corresponding compound with at least two functional groups X that at least the majority of a such connection does not go into solution. Such inclusion can, for example happen in such a way that a melt of a corresponding compound with at least two functional groups X are mixed with a compound, the one Has water solubility of more than 1 g / l, the melt cooled and then is ground to a desired size.

A microcapsule according to the invention can each of the compounds mentioned above contained individually or as a mixture of two or more of the types of compounds mentioned. In the context of the present invention, “connection types” are used in each case Compounds with different functional groups X understood. So one can Microcapsule according to the invention, for example a polyamine or a mixture of two or more different polyamines, a polyhydroxy compound or a mixture of two or more different polyhydroxy compounds or a mixture of one or contain more polyamines and one or more polyhydroxy compounds.

In the context of a preferred embodiment of the present invention, a microcapsule according to the invention one or more polyamines or one Polyhydroxy compound or more polyhydroxy compounds, particularly preferred however, one or more polyamines.

In addition to a connection with at least two functional groups X or one Mixture of two or more of them as described above The capsule content of a microcapsule according to the invention can still be described contain other additives.

The further additives can have, for example, water solubility, the is below the above limit of about 1 g / l. However, it is under the present invention also possible to use additives whose water solubility exceeds the stated limit. In this case, however, the additives, such as already described above, in a matrix of the substance with a correspondingly lower Water solubility must be embedded.

Other suitable additives are, for example, catalysts which effect the reaction a compound contained in the capsule content of a microcapsule according to the invention at least two functional groups X with a compound opposite those functional groups X has reactive functional groups, catalyze.

Examples of suitable catalysts are tertiary amines, e.g. B. triethylamine, 1,4- Diazabicyclo [2,2,2] octane (= DABCO) dimethylbenzylamine, bis-dimethylaminoethyl ether and bis-methylaminomethylphenol. 1-methylimidazole is particularly suitable, 2-methyl-1-vinylimidazole, 1-allylimidazole, 1-phenylimidazole, 1,2,4,5-tetramethylimidazole, 1- (3-aminopropyl) imidazole, pyrimidazole, 4-dimethylamino-pyridine, 4-pyrrolidinopyridine, 4-morpholino-pyridine, 4-methylpyridine and dimorpholinodiethyl ether.

Organotin compounds can also be used as catalysts. This means compounds which contain both tin and an organic radical, in particular compounds which contain one or more SnC bonds. Organotin compounds in the broader sense include e.g. B. salts such as tin octoate and tin stearate. The tin compounds in the narrower sense primarily include compounds of tetravalent tin of the general formula R _{n + 1} SnZ _3-n , where n stands for a number from 0 to 2, R stands for an alkyl group or an aryl group or both, and Z finally represents an oxygen, sulfur or nitrogen compound or a mixture of two or more thereof. R expediently contains at least 4 carbon atoms, in particular at least 8. The upper limit is generally 12 carbon atoms. Z is preferably an oxygen compound, that is to say an organotin oxide, hydroxide, carboxylate or an ester of an inorganic acid. However, Z can also be a sulfur compound, that is to say an organotin sulfide, thiolate or a thiosate. In the Sn-S compounds, especially thioglycolic acid esters are suitable, e.g. B. Compounds with the following residues:

S-CH ₂ -CH ₂ -CO-O- (CH ₂ ) ₁₀ -CH ₃ or

S-CH ₂ -CH ₂ -CO-O-CH ₂ -CH (C ₂ H ₅ ) -CH ₂ -CH ₂ -CH ₂ -CH ₃ .

Another class of compounds suitable as catalysts are the dialkyltin (IV) carboxylates (Z = O-CO-R ¹ ). The carboxylic acids have 2, preferably at least 10, in particular 14 to 32, carbon atoms. Dicarboxylic acids can also be used. Examples of suitable acids are adipic acid, maleic acid, fumaric acid, terephthalic acid, phenylacetic acid, benzoic acid, acetic acid, propionic acid and in particular caprylic, capric, lauric, myristic, palmitic and stearic acid. For example, dibutyltin diacetate and dilaurate and dioctyltin diacetate and dilaurate are particularly suitable.

Tin oxides and sulfides as well as thiolates are also within the scope of the present invention suitable. Specific compounds are: bis (tributyltin) oxide, dibutyltin didodecylthiolate, Dioctyltin dioctyl thiolate, dibutyltin bis (2-ethyl-hexyl thioglycolic acid), Octyltin tris (2-ethylhexyl thioglycolic acid), dioctyltin bis (2-ethylhexoate thioethylene glycol), Dibutyltin bis (thioethylene glycol laurate), dibutyltin sulfide, dioctyltin sulfide, Bis (tributyltin) sulfide, dibutyltin bis (2-ethylhexyl thioglycolic acid), dioctyltin bis (thioethylene glycol 2-ethylhexoate), trioctyltin thioethylene glycol 2-ethylhexoate and Dioctyltin bis (2-ethylhexyl thiolatoacetate), bis (S, S-methoxycarbonylethyl) tin bis (2-ethylhexyl thiolatoacetate), bis (S, S-acetyl-ethyl) tin bis (thiolatoacetic acid) 2-ethyl-hexyl ester), tin (II) octyl thiolate and tin (II) thioethylene glycol 2-ethyl hexoate.

Also mentioned are: dibutyltin diethylate, dihexyltin diaminexylate, Dibutyltin diacetylacetonate, dibutyltin diethylacetylacetate, bis (butyldichlorotin) oxide, Bis (dibutylchlorotin) sulfide, tin (II) phenolate, tin (II) acetylacetonate, and others α-dicarbonyl compounds such as acetylacetone, dibenzoylmethane, benzoylacetone, Ethyl acetoacetate, n-propyl acetoacetate, ethyl α, α'-diphenylacetoacetate and Dehydroacetessigsäure.

A microcapsule according to the invention can also contain one as capsule content Contain photosensitizer or a mixture of two or more photosensitizers. A "photosensitizer" is used in the context of the present invention Compound understood which the radiation energy absorbed by it on molecules transmits which do not absorb the radiated energy itself or that of it directly absorbs absorbed radiation energy into heat.

Photosensitizers suitable according to the invention can have, for example, one or more functional groups X, for example OH, NH ₂ or NHR ¹ groups. Suitable photosensitizers are, for example, benzophenone, Michler's ketone, 2-acetonaphthone, chrysene, fluorenone, benzil, 1,2-benzanthrazene, acridine, anthracene, thioxanthone or fluorenone or compounds which are commercially available under the name Thinuvin® (manufacturer: Ciba Geigy) are. Also suitable are triazines, benzotriazoles and benzophenone derivatives, as described, for example, in WO 98/03489, UV absorbers, as described, for example, in EP-A 0 893 119, EP-A 1 032 563, Kunststoffe (1999), 89 ( 7), 87-90 or Ullmanns Encyclopedia of Industrial Chemistry, Sixth Edition, 2000 Electronic Release, PAINTS AND COATINGS - Paint additives 5.7 Light Stabilizers or Ullmanns Encyclopedia of Industrial Chemistry, Sixth Edition, 2000 Electronic Release, Photochemistry, Table 8 , Reference is expressly made to the photoactive compounds mentioned in the corresponding publications. The compounds are considered part of the disclosure of the present text.

In addition to a compound with functional groups X or a mixture of two or more compounds with functional groups X and optionally a catalyst or a mixture of two or more catalysts or a photosensitizer or a mixture of two or more photosensitizers or the like Mixtures of catalysts and photosensitizers can contain a capsule microcapsule according to the invention have further additives. Which includes for example plasticizers, antioxidants, stabilizers, dyes, fragrances, Pigments and the like.

Examples of plasticizers are plasticizers based on phthalic acid used, in particular dialkyl phthalates, phthalic acid esters as plasticizers are preferred, those having a 6 to about 12 carbon atoms, linear alkanol were esterified. Dioctyl phthalate is particularly preferred.

Benzoate plasticizers are also suitable as plasticizers, for example Sucrose benzoate, diethylene glycol dibenzoate and / or diethylene glycol benzoate, in which about 50 to about 95% of all hydroxyl groups have been esterified, phosphate Plasticizers, for example t-butylphenyl diphenyl phosphate, polyethylene glycols and their derivatives, for example diphenyl ether of poly (ethylene glycol), liquid Resin derivatives, for example the methyl ester of hydrogenated resin, vegetable and animal oils, for example glycerol esters of fatty acids and their Polymerization products.

Stabilizers or antioxidants which can be used as additives in the context of the invention include hindered phenols of high molecular weight (M _n ), polyfunctional phenols and sulfur- and phosphorus-containing phenols. Phenols which can be used as additives in the context of the invention are, for example, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene; Pentaerythritol tetrakis 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate; n-octadecyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate; 4,4-methylenebis (2,6-di-tert-butylphenol); 4,4-thiobis (6-tert-butyl-o-cresol); 2,6-di-tert-butylphenol; 6- (4-hydroxyphenoxy) -2,4-bis (n-octyl-thio) -1,3,5-triazine; Di-n-octadecyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate; 2- (n-octylthio) ethyl 3,5-di-tert-butyl 4-hydroxybenzoate; and sorbitol hexa [3- (3,5-di-tert-butyl-4-hydroxphenyl) propionate].

Further additives can be included in the microcapsules according to the invention to vary certain properties. Among them, for example Dyes such as titanium dioxide, fillers such as talc, clay and the like.

Are also suitable as additives in the context of the present invention Propellant. Suitable propellants are, for example, compounds that are within the area of application of the adhesive, preferably at a temperature of more decompose at 50, especially more than 60 or more than 70 ° C with gas evolution. Such blowing agents support, for example, the opening of an inventive one Microcapsules and the leakage of a substance contained in such a microcapsule. Suitable blowing agents are, for example, those under the trade names LUVOPOR LUV / N XF, LUVOPOR 9301 or LUVOPOR 9302 from Lehmann and Voss, Hamburg, available compounds or those under the trade names TRACEL DBN 120 NER and Unicell H available 2-component blowing agents.

In the context of a preferred embodiment of the present invention, a Microcapsule according to the invention the above additives in an amount of up to about 30% by weight, especially about 0.1 to about 20 or about 0.5 to about 10 or about 1 up to about 5% by weight, for example about 2 to about 4% by weight.

A microcapsule according to the invention has the capsule content described above a capsule shell. The advantages of the invention can be achieved if the Capsule shell by reaction of functional groups X of the capsule content with an in Water-emulsifiable compound, which compared to the functional groups X des Has capsule contents reactive functional groups Z has arisen.

The capsule wall of a microcapsule according to the invention is replaced by a chemical one Microencapsulation process manufactured. Here is a wall formation from monomers or oligomeric starting materials by polycondensation or polyaddition are preferred.

A known encapsulation process is based on the principle of the interface Polycondensation. However, while in the known from the prior art Process for the production of microcapsule, for example a monomer component in dissolved in one solvent and this solution in another, not with the first Solvent-miscible solvent is dispersed, the manufacture of the Microcapsules according to the invention proceed in such a way that the capsule content forming component as an aqueous dispersion and the capsule shell forming Component is present as an aqueous emulsion.

In the context of the present invention, therefore, to build the capsule shell Connections used, on the one hand compared to those on the surface of the Functional groups present in capsule content X reactive functional groups Z, on the other hand, these functional groups Z compared to water in one Emulsion are essentially stable for at least a limited period of time.

A connection suitable for the construction of the capsule shell is therefore preferably such selected to be used as an aqueous emulsion within a period of at least 1 minute preferably within a period of at least about 3, 5, 7 or 10 minutes less than about 50%, preferably less than about 40, 30, 20 or 10% of their reactive functional groups Z by reaction between water and the functional group Z loses.

Suitable functional groups Z are suitable for the purposes of the present invention especially isocyanate groups or epoxy groups. As part of a preferred Embodiments of the present invention are used to form the capsule shell, Compounds used which have one isocyanate group or two or more isocyanate groups exhibit.

Suitable compounds with at least two isocyanate groups are, for example Compounds such as 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (Isophorone diisocyanate, IPDI), diphenylmethane-2,4'-diisocyanate, diphenylmethane-2,2'- diisocyanate or diphenylmethane-4,4'-diisocyanate or isocyanates based on MDI like that Product Sovermol-I-1043-VI sold by Henkel, Desmodur VP-L / UE-6105-A or Z-4273 (fatty acid modified, polyfunctional aliphatic Isocyanates) from Bayer, aliphatic polyisocyanate prepolymers such as those from Bayer are sold under the name Desmodur E-3150, Poly (diphenylmethane diisocyanate) as sold by Dow under the trade name PAPI-135 or PAPI-M-235 is available or a mixture of different homologues Diphenylmethane diisocyanate as it is under the trade name under Voranate-M-22 from is available from Dow, or mixtures of two or more thereof. Isocyanates, the Emulsifiability in water for the present purpose is not sufficient Framework of the present invention, for example with the addition of a protective colloid be emulsified. Suitable protective colloids are known to the person skilled in the art.

Three or more are also suitable as compounds with two or more isocyanate groups higher quality isocyanates, such as those obtained by oligomerization of Diisocyanates are available. Examples of such 3 and higher polyisocyanates are the triisocyanurates from HDI or IPDI or their mixtures or their mixtures Diisocyanurates. Also suitable are trivalent and higher polyisocyanates as they are by reacting the isocyanates with compounds that are 3 or more opposite Have isocyanate reactive groups, can be obtained. In particular, there are Suitable polyisocyanates, the molecular constituent polyether groups, in particular Contain polyethylene oxide groups or ionic groups or short-chain esters. Polymeric isocyanates such as those sold under the name LIOFOL by Henkel company, especially Liofol UR 5888-21.

In principle, all are suitable as compounds having two or more epoxy groups Compounds with a molecular weight of up to about 800, especially at about 600 which have one or more epoxy groups which have a sufficiently rapid reactivity with the functional groups X of the capsule contents.

Such compounds can be implemented, for example, by converting polyvalent ones Phenols such as bisphenol-A, bisphenol-F, catechol or resorcinol or of polyvalent ones Alcohols such as glycerin, trimethylolpropane, pentaerythritol, sugars such as glucose, Fructose, mannose, galactose, dextrose, sorbitol or mannitol and their Reaction products with ethylene oxide or propylene oxide or a mixture thereof or from Hydroxycarboxylic acids such as p-hydroxybenzoic acid or 2-hydroxynaphthenic acid Obtained epichlorohydrin. Furthermore as at least two epoxy groups Suitable compounds are the reaction products of amines such as 4,4'- Diaminodiphenylmethane, m-aminophenol and the like, for example those Reaction products of the amines already mentioned above as capsule content Epichlorohydrin. Are particularly suitable in the context of the present invention Epoxyhexahydrobenzoic acid 2 ', 3'-epoxycyclohexylmethyl ester (Degacure-K-126, Manufacturer: Degussa), epoxides such as those under the trade name Rütapox Thinner S or Rütapox WF are available from Bakelite, butadiene diepoxide, 1,2,8,9-diepoxylimones, dicyclopentadiene diepoxide, bisphenol-A-epichlorohydrin Diepoxidharz, as for example under the trade name Lekutherm X-20 from Bayer is available, 1,2-Epoxydodecan, 1,2-Epoxytetradecan or Reaction products of bisphenol A with chloromethyloxirane with a average molecular weight less than about 700.

In the context of a preferred embodiment of the present invention, the Capsule shell of a microcapsule according to the invention has a wall thickness of at least one monomolecular position of the compound used to manufacture the capsule shell, for example at least about 10 nm.

A microcapsule according to the invention can be used in the context of the present invention as Capsule shell, for example, have only one layer. However, it is according to the invention also provided that a capsule shell of a microcapsule according to the invention two or has more layers. For example, a first layer can be used as a capsule shell already described above. If necessary, such a first Another layer or more layers are applied, this order being carried out by conventional encapsulation processes, for example by Spray drying or coacervation with colloids, for example gelatin or Gum arabic, can be done. In addition to simple or complex coacervation, too embedding by interfacial polymerization or by dripping. It is according to the invention also possible in a second step with a further implementation a reactive partner, for example an acid chloride, to carry out the To further seal the capsule shell. Furthermore, the formation or sealing of the Capsule shell through a polymer or a mixture of two or more polymers Different techniques, for example from solution, are deposited on the capsule shell become. In the context of a preferred embodiment of the present invention a capsule shell of a microcapsule according to the invention 1 to 3 layers, in particular 1 or 2 layers on.

The microcapsules according to the invention are produced by contacting one aqueous dispersion of a non-water-soluble compound with at least two towards isocyanate groups or epoxy groups or carboxyl groups or activated Functional groups X reactive with carboxyl groups and having a water-emulsifiable one Compound that is reactive towards the functional groups X of the capsule contents has functional groups Z.

The present invention therefore also relates to a method for producing a Microcapsule, in which an aqueous dispersion of a water-insoluble compound with at least two against isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl-reactive functional groups X with one in water emulsifiable compound opposite the functional groups X of the capsule contents has reactive functional groups Z, is added.

The capsule content must be carried out as a solid in order to carry out the process according to the invention are in ground form. Due to the extremely low tendency to agglomerate of microcapsules coated by a method according to the invention determined in essentially the particle size of the particles provided as capsule contents Particle size of the microcapsules. It is therefore within the scope of the present invention provided that the method according to the invention is carried out with solid particles, which have an average particle size of at most about 20 microns, preferably one Particle size from about 0.5 to about 10 or about 0.8 to about 5 microns or about 1 to about 3 µm.

If a mixture of different solids is to be used as the capsule content, then these solids are preferably first mixed in the melt, cooled and then grind to the desired size.

The solids intended as capsule contents are then dispersed in water. The dispersion is preferably carried out in demineralized or distilled water. to In principle, any devices can be used to produce the dispersion be a division of the solid particles to be dispersed into their primary particles allow. While many dispersed processes known from the prior art The inventive method can require special dispersed devices already in conventional stirring apparatus, for example with a conventional stirring fish or a KPG stirrer and a round bottom flask. Because of the good Dispersion properties of water for the capsule content according to the invention Usable connections are sufficient for relatively low speeds, for example Speeds of up to about 1000 rpm, in particular about 200 to about 600 rpm, for Dispersion of the particles. Colloid mills, for example, are also suitable, High pressure homogenizers or ultrasound treatment.

The weight ratio of solid particles to water should be about 1: 3 to about 1:20. in particular about 1: 5 to about 1:15 or about 1: 8 to about 1:12.

Such a dispersion of solid particles in water is then in a first embodiment of the method according to the invention with an emulsion of a in water emulsifiable compound, which compared to the functional groups X des Has capsule contents reactive functional groups Z added. Appropriate Emulsions of a compound which is functional group X des Capsule content has reactive functional groups Z, can be entered such a compound in water and subsequent emulsification according to the usual generate methods known in the art.

The weight ratio of compounds which differ from the functional groups X of the capsule contents have reactive functional groups Z to water for example about 1: 1 to about 1:25, in particular about 1: 2 to about 1:20 or about 1: 5 until about 1:15.

In a next step, the dispersion of the solid particles with the Emulsion added. This can be done, for example, in such a way that the entire Emulsion of the dispersion of solid particles in a short period of a few Seconds is added. However, it is preferred within the scope of the present invention if the emulsion disperses the solid particles over a long period of time, for example over a period of about 1 to about 1 hundred minutes becomes.

It has proven to be advantageous to add the emulsion to the dispersion reaction mixture obtained after completion of the addition of the emulsion still for one certain period, for example for a period of about 0.5 to about 5 hours is stirred.

The inventive method can at temperatures of about 5 to about 50 ° C. be performed. In the context of a preferred embodiment of the present Invention, however, will be at ambient temperature, i.e. H. a temperature of about 15 performed up to about 25 ° C.

After completion of the reactions, the microcapsules according to the invention are in the essentially as primary particles, d. H. in non-agglomerated form as an aqueous dispersion in front. This dispersion can then be obtained by customary processes for obtaining Solids from aqueous dispersion, for example by filtration, sedimentation, Centrifugation with subsequent drying or spray drying obtained as a solid become. In addition, the microcapsules thus obtained can, if desired, with a Solvent that does not attack the capsule shell can be washed.

It may be advantageous if the dispersion of the so produced microcapsules according to the invention is subjected to a treatment which aggregates of two or more particles optionally present in the dispersion disaggregated. A suitable method for this is, for example Sonication. For this purpose, the dispersion of the microcapsules according to the invention for a period of about 0.5 to about 200, for example about 1 to about 50 minutes in an ultrasonic bath at a temperature of about 10 to about 50 ° C, for example at treated about 15 to about 25 ° C. Other suitable pretreatment procedures are for example the treatment of the dispersion of the microcapsules according to the invention in Ultraturrax in a colloid mill, in a homogenizer, in a mixing turbine or in one Static mixer.

Within the scope of a further embodiment of the present invention, one such produced microcapsule according to the invention, for example, with another Capsule shell. Such further capsule shells can, for example, by mechanical-physical microencapsulation processes are applied.

A first suitable mechanical-physical microencapsulation process is for example spray drying. It is a very general one Applicable method for microencapsulation, in which an emulsion or dispersion is atomized in a hot, inert gas stream. In a continuous phase that too Surrounding the particles to be encapsulated in the spray drop is a film-forming polymer solved. When the volatile components evaporate, this solution shrinks to a pure one Polymer shell that firmly encloses the particle to be encapsulated. Such capsules fall as a free-flowing, dry powder.

The capsule shell then contains at least one water-soluble or at least one water-dispersible polymer having a molecular weight greater than about 100, in particular has more than about 2000 or 3000.

A water-soluble polymer is used in the context of the present invention Understand polymer, which is an essentially molecularly dispersed solution in water forms. A water-dispersible polymer is used in the context of the present Invention understood a polymer in water, optionally in the presence of a suitable emulsifier, forms a stable dispersion. As part of a preferred Embodiment of the present invention, the capsule shell contains a polymer which is either water-soluble or self-dispersible in water. Under one in water self-dispersible polymers are used in the context of the present invention Understand polymer that in water essentially without the addition of an emulsifier Dispersion forms.

In the context of the present invention as part of a further layer of Capsule shell-suitable polymers preferably have one or more OH groups or one or more COOH groups or sulfonic acid groups or both. Suitable polymers are, for example, cellulose or cellulose ethers such as Carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyalkyl cellulose, in particular hydroxyethyl cellulose or their mixed ethers, such as methyl hydroxyethyl or -hydroxypropyl cellulose, carboxymethyl hydroxyethyl cellulose or Ethylhydroxyethylcellulose or a mixture of two or more of the polymers mentioned. Farther Suitable are, for example, polymers which are formed by polymerizations of vinyl acetate and then partial or complete saponification of part or all of them Let acetate groups be preserved. These include in particular polyvinyl alcohols that still have about 1 to about 70% acetate groups.

Copolymers are also suitable, in addition to vinyl acetate during their production at least one other monomer was used and its vinyl acetate content entirely or was partially saponified. Corresponding copolymers can be used as statistical Copolymers or used as block copolymers. Suitable comonomers are for example acrylic acid, methacrylic acid, ethylene, styrene or α-methylstyrene, where corresponding block copolymers are based on two or more of the monomers mentioned can.

Within the scope of a further preferred embodiment of the present invention as a component of a further layer of the capsule shell, a styrene / vinyl acetate copolymer used, the vinyl acetate units of at least 60%, preferably at least 80% or 90% are saponified. If as part of another layer of the capsule shell If polyvinyl alcohol is used, polyvinyl alcohol with a Degree of saponification from about 70 to about 90%.

Also suitable are the sulfonic acid derivatives of the abovementioned compounds, for example Na polystyrene sulfonate with a molecular weight ( _MW ) of about 50,000 to about 100,000. Also suitable are those in "Advances in Polymer Science, 136, A. Prokop, D. Hunkeler et al., Watersoluble Polymers for Immunoisolation, p. 5, Table 2 ff., Springer-Verlag, Berlin / Heidelberg / New York, 1998 "described water-soluble polymers, which are expressly incorporated herein by reference and which are considered part of the present disclosure.

Mixtures of two or more polymers are also suitable, at least one of the polymers present in the mixture has OH groups. As part of a preferred embodiment of the present invention Mixtures of hydrophobic and hydrophilic polymers are used, in particular Mixtures containing styrene and at least one hydrophilic polymer, for example Cellulose or a cellulose derivative or polyvinyl alcohol. As part of another Embodiment of the invention are polymer mixtures as a material for the further Layer of the capsule shell used by the polymerization of styrene in the presence a hydrophilic polymer, for example in the presence of cellulose or in In the presence of a cellulose ether or in the presence of polyvinyl alcohol were.

The polymers contained in such a further layer of the capsule shell have a Molecular weight of at least about 1000, preferably at least about 3000. in the This is within the scope of a further embodiment of the present invention Molecular weight of the polymers contained in the capsule shell at least about 5000, for example at least about 10,000. The upper limit for the molecular weight the polymer contained in the capsule shell is preferably about 1,000,000 however below. Suitable upper limits for corresponding molecular weights are for example 200,000, 100,000 or about 50,000. If as part of the further Layer of the capsule shell, for example, a cellulose ether is used Molecular weight from about 15,000 to about 40,000 proven. If as part of the Capsule shell, for example, a polyvinyl alcohol is used, it should Molecular weight is about 10,000 to about 35,000.

In a preferred embodiment of the present invention, the Spray drying carried out so that the temperature of the aqueous dispersion or Solution about 5 to about 70 ° C, for example about 10 to about 50 ° C or about 15 to is about 30 ° C. The temperature of the air stream is preferably set in such a way that it is about 100 to about 200, for example about 120 to about 160 ° C, the Temperature of the air flow is set at least such that, depending on the type and design of the spray dryer used, the temperature of the capsules to be dried does not rise above the temperature required to open the capsule.

Further application of a further layer to the capsule shell of the invention Processes suitable for microcapsules are, for example, the multi-component nozzle process or the coating in the fluidized bed.

The microcapsules according to the invention can be used in particular in the production of Use adhesives. For this purpose, the microcapsules according to the invention with a Matrix of a compound or a mixture of two or more compounds surrounded, which harden with the capsule content to form a covalent bond can. The term "hardening" refers to in the context of the present invention a chemical curing reaction that involves increasing molecular weight or crosslinking or both.

• - Komponente A mindestens eine erfindungsgemäße Mikrokapsel oder eine nach einem erfindungsgemäßen Verfahren hergestellte Mikrokapsel, und
• - Komponente B mindestens eine Verbindung mit mindestens zwei funktionellen Gruppen Y enthält.

The present invention therefore also relates to an adhesive comprising at least one component A and one component B, wherein

• Component A at least one microcapsule according to the invention or a microcapsule produced by a method according to the invention, and
• - Component B contains at least one compound with at least two functional groups Y.

Component A of the adhesive according to the invention can be used in the context of the present In addition to the microcapsules according to the invention, the invention also has a further constituent or have two or more other components. As further components in the context of the present invention also considered those components which consist exclusively of the compounds contained in the microcapsules, which but have a different morphology. A different morphology can For example, consist in that the ingredient referred to as the capsule content is not of the capsule shell is enclosed, but only at one or more points adheres to the capsule shell and thus an aggregate of capsule contents and capsule shell material forms. Likewise, the term "different morphology" refers to aggregates that consist exclusively of the compounds contained in the microcapsules, in which however, several of the constituents forming the capsule content form on one Capsule shell material adhering to existing, for example spherical, structures.

Component B of the adhesive according to the invention contains, for example, at least one Connection with at least two functional groups Y. One in component B of the Compound containing adhesive according to the invention can be two or more identical carry functional groups Y. However, it is also possible that a component each compound containing adhesive two or more different functional groups Y carries.

In principle, all functional groups which are suitable as functional groups Y are the functional groups X of the capsule content to form a covalent Bond can react. In particular, the functional group Y represents a functional group Group selected from the group consisting of isocyanates, epoxides, carboxylic acids, Carboxylic acid esters, carboxylic acid chlorides or carboxylic acid anhydrides.

Within the scope of a preferred embodiment of the present invention functional group Y for an epoxy group or an isocyanate group.

In a further preferred embodiment, component B contains at least one epoxy resin, as can be seen, for example, by reacting polyhydric phenols such as bisphenol-A, bisphenol-F, catechol or resorcinol or polyhydric alcohols such as glycerin, trimethylolpropane, pentaerythritol, sugars such as Glucose, fructose, mannose, galactose, dextrose, sorbitol or mannitol as well as their Reaction products with ethylene oxide or propylene oxide or a mixture thereof, or of Hydroxycarboxylic acids such as p-hydroxybenzoic acid or 2-hydroxynaphthenic acid Epichlorohydrin is available. Polyglycidyl esters such as it by reacting polycarboxylic acids such as phthalic acid, isophthalic acid or Terephthalic acid with epichlorohydrin are available. Also suitable as epoxy resins are the reaction products of amines such as 4,4'-diaminodiphenylmethane, m-aminophenol and the like, for example the reaction products of the above Amines called capsule contents, with epichlorohydrin. Polymers are also suitable Epoxy resins, such as those obtained by implementing appropriate prepolymers, for example Prepolymers containing OH groups or NH groups available with epichlorohydrin are. Such polymeric epoxy resins can be, for example, two or more Have epoxy groups. The epoxy groups can, for example, at the chain end of the Polymers can be arranged, but they can also be within the polymer chain be arranged.

Examples of suitable prepolymers are polymeric polyol components such as that Reaction products of low molecular weight polyfunctional alcohols with alkylene oxides, so-called polyethers. The alkylene oxides preferably have 2 to 4 carbon atoms. The reaction products of ethylene glycol, propylene glycol, the isomeric butanediols or hexanediols with ethylene oxide, propylene oxide or Butylene oxide, or mixtures of two or more thereof. Furthermore, the Reaction products of polyfunctional alcohols, such as glycerol, trimethylolethane or Trimethylolpropane, pentaerythritol or sugar alcohols, or mixtures of two or more of it, suitable with the alkylene oxides mentioned to polyether polyols. Especially suitable are polyether polyols with a molecular weight of about 100 to about 10,000, preferably from about 200 to about 5,000. Is very particularly preferred Within the scope of the present invention polypropylene glycol with a molecular weight of about 300 to about 2,500. Also as a polyol component for the production of the epoxides Suitable are polyether polyols, such as those from the polymerization of Tetrahydrofuran arise.

The polyethers are prepared in a manner known to those skilled in the art by reacting the Starting compound with a reactive hydrogen atom with alkylene oxides, for example Ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran or epichlorohydrin or mixtures of two or more of them.

Suitable starting compounds are, for example, water, ethylene glycol, propylene glycol 1, 2 or -1.3, 1,4-butylene glycol or -1.3-1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-hydroxymethylcyclohexane, 2-methyl-1,3-propanediol, glycerin, trimethylolpropane, Hexanetriol-1,2,6, butanetriol-1,2,4 trimethylolethane, pentaerythritol, mannitol, sorbitol, Methylglycosides, sugar, phenol, isononylphenol, resorcinol, hydroquinone, 1,2,2- or 1,1,2-tris (hydroxyphenyl) ethane, ammonia, methylamine, ethylenediamine, tetra or Hexamethylene amine, triethanol amine, aniline, phenylenediamine, 2,4- and 2,6-diaminotoluene and polyphenylpolymethylene polyamines, such as those found in aniline Get formaldehyde condensation, or mixtures of two or more of them.

Also for use as a polyol component in the production of corresponding epoxies suitable are polyethers which have been modified by vinyl polymers. Such products are available, for example, by styrene or acrylonitrile, or a mixture thereof, in the Be polymerized in the presence of polyethers.

Also as a polyol component for the production of corresponding epoxides polyester polyols with a molecular weight of about 200 to about 10,000 are suitable. For example, polyester polyols can be used by the reaction of low molecular weight alcohols, especially of ethylene glycol, diethylene glycol, Neopentyl glycol, hexanediol, butanediol, propylene glycol, glycerin or trimethylol propane with caprolactone. Also as polyfunctional alcohols for the production of Suitable polyester polyols are 1,4-hydroxymethylcyclohexane, 2-methyl-1,3-propanediol, Butanetriol-1, 2,4, triethylene glycol, tetraethylene glycol, polyethylene glycol, Dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol.

Other suitable polyester polyols can be produced by polycondensation. So can difunctional and / or trifunctional alcohols with a deficit of dicarboxylic acids and / or tricarboxylic acids, or their reactive derivatives, to polyester polyols be condensed. Suitable dicarboxylic acids are, for example, succinic acid and their higher homologues with up to 16 carbon atoms, as well as unsaturated dicarboxylic acids such as Maleic acid or fumaric acid and aromatic dicarboxylic acids, especially those isomeric phthalic acids, such as phthalic acid, isophthalic acid or terephthalic acid. As Tricarboxylic acids are, for example, citric acid or trimellitic acid. in the Within the scope of the invention, polyester polyols from at least one of the called dicarboxylic acids and glycerol, which have a residual content of OH groups exhibit. Particularly suitable alcohols are hexanediol, ethylene glycol, diethylene glycol or neopentyl glycol or mixtures of two or more thereof. Particularly suitable Acids are isophthalic acid or adipic acid or a mixture thereof.

In the context of the present invention, for example, as a polyol component for Production of the epoxides used are dipropylene glycol as well Polyester polyols, preferably polyester polyols obtainable by polycondensation of Hexanediol, ethylene glycol, diethylene glycol or neopentyl glycol or mixtures of two or more of them and isophthalic acid or adipic acid, or mixtures thereof.

High molecular weight polyester polyols include, for example Reaction products of polyfunctional, preferably difunctional alcohols (optionally together with small amounts of trifunctional alcohols) and polyfunctional, preferably difunctional carboxylic acids. Instead of freer Polycarboxylic acids can (if possible) also the corresponding ones Polycarboxylic anhydrides or corresponding polycarboxylic acid esters with alcohols preferably 1 to 3 carbon atoms are used. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic or heterocyclic, or both. You can optionally substituted, for example by alkyl groups, alkenyl groups, Ether groups or halogens. Examples of polycarboxylic acids are succinic acid, Adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, Terephthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, Hexahydrophthalic anhydride, tetrachlorophthalic anhydride, Endomethylene tetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, Dimer fatty acid of trimer fatty acid or mixtures of two or more thereof are suitable. If necessary, minor amounts of monofunctional fatty acids in the Reaction mixture to be present.

The polyester polyols can optionally contain a small proportion Have carboxyl end groups. From lactones, for example ε-caprolactone or hydroxycarboxylic acids, for example, ω-hydroxycaproic acid, available polyesters can also be used become.

Polyacetals are also suitable as polyol components. Among polyacetals Compounds understood as they from glycols, for example diethylene glycol or Hexanediol or a mixture thereof with formaldehyde are available. Within the scope of the invention Polyacetals that can be used can also be obtained by polymerizing cyclic acetals be preserved.

Polycarbonates are also suitable as the polyol component. Polycarbonates can for example by the reaction of diols such as propylene glycol, 1,4-butanediol or 1,6-hexanediol, diethylene glycol, triethylene glycol or tetraethylene glycol or Mixtures of two or more of them with diaryl carbonates, for example Diphenyl carbonate, or phosgene, can be obtained.

Particularly suitable epoxides are, for example, epoxy DER-331 (manufacturer: Dow Chemicals) or the Epikote series epoxides, for example Epikote 828 (manufacturer: Shell AG). This is particularly suitable in the context of the present invention Reaction product of bisphenol-A and epichlorohydrin.

In the context of a further preferred embodiment of the present invention Component B contains one, two or more compounds which are isocyanate groups wear functional group Y. Such a compound bearing isocyanate groups can for example, be low molecular weight, d. i.e., for example a molecular weight of less than about 250. However, it is also possible that the isocyanate groups bearing compound has a molecular weight higher than 250. In this case can, for example, as compounds bearing isocyanate groups Polyurethane prepolymers are used.

Compounds which are suitable as isocyanate groups are, for example, compounds such as ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and mixtures from two or more thereof, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (Isophorone diisocyanate, IPDI), 2,4- and 2,6-hexahydrotoluenediisocyanate, Tetramethylxylylene diisocyanate (TMXDI), 1,3- and 1,4-phenylene diisocyanate, 2,4- or 2,6- Tolylene diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-2,2'-diisocyanate or diphenylmethane-4,4'-diisocyanate or mixtures of two or more of the above Diisocyanates.

Also suitable for the purposes of the present invention are 3- or higher quality isocyanates, such as those obtained by oligomerization of Diisocyanates are available. Examples of such trivalent and higher polyisocyanates are the triisocyanurates from HDI or IPDI or their mixtures or their mixtures Triisocyanurates.

Also suitable are polyurethane prepolymers, such as those obtained by the reaction of polyfunctional isocyanates with a low molecular weight or polymeric Polyol component are available. Suitable polyfunctional isocyanates are for example the isocyanates described above.

A large number of polyols can be used as the low molecular weight polyol component. For example, these are aliphatic alcohols with 2 to 4 OH groups per molecule. The OH groups can be either primary or secondary. Suitable aliphatic alcohols include, for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol and their higher homologs or isomers, as described for the person skilled in the art from a gradual extension of the hydrocarbon chain by one CH ₂ group or by introducing branches into the carbon chain. Highly functional alcohols such as glycerol, trimethylolpropane, pentaerythritol and oligomeric ethers of the substances mentioned with themselves or in a mixture of two or more of the ethers mentioned are also suitable.

As the polymeric polyol component, those already mentioned above are suitable for producing the Polymeric polyol components suitably described as epoxides.

Suitable polyurethane prepolymers in the context of the present invention preferably a molecular weight of more than about 350, for example more than about 500 or more than about 1000. The upper limit of the molecular weight is in the Usually by the application viscosity of a corresponding one Limited adhesive containing polyurethane prepolymer. If with such Adhesive, for example, should be dispensed with solvent, so it will Molecular weight of such a polyurethane prepolymer is generally chosen such that that the adhesive has a suitable application viscosity. In this case corresponding polyurethane prepolymers have a molecular weight that for example less than about 50,000, in particular less than about 10,000. However, if the adhesive according to the invention can contain solvents, so can Polyurethane prepolymers with corresponding higher molecular weights are used become.

In principle, all solvents commonly used in polyurethane chemistry are used as solvents Solvents can be used, in particular esters, ketones, halogenated hydrocarbons, Alkanes, alkenes and aromatic hydrocarbons. Examples of such solvents are Methylene chloride, trichlorethylene, toluene, xylene, butyl acetate, amyl acetate, isobutyl acetate, Methyl isobutyl ketone, methoxybutyl acetate, cyclohexane, cyclohexanone, dichlorobenzene, Diethyl ketone, di-isobutyl ketone, dioxane, ethyl acetate, ethylene glycol monobutyl ether acetate, Ethylene glycol monoethyl acetate, 2-ethylhexyl acetate, glycol diacetate, heptane, hexane, Isobutyl acetate, isooctane, isopropyl acetate, methyl ethyl ketone, tetrahydrofuran or Tetrachlorethylene or mixtures of two or more of the solvents mentioned.

If component B in addition to the compounds described above with functional Groups Y still have compounds with functional groups X are suitable all compounds with functional groups X already described above.

In the adhesive according to the invention, the equivalent ratio of reactive functional groups X in component A to functional groups Y in component B about 1: 100 to about 1: 1. The term "equivalent ratio" is used in the context of present invention, the molar ratio of functional groups X to functional Groups Y understood.

• - Komponente A mindestens eine erfindungsgemäße Mikrokapsel, und
• - Komponente B mindestens eine Verbindung mit mindestens zwei funktionellen Gruppen Y enthält,

vermischt werden. Another object of the present invention is a method for producing an adhesive according to any one of claims 8 to 10, in which a component A and a component B, wherein

• - Component A at least one microcapsule according to the invention, and
• Component B contains at least one compound with at least two functional groups Y,

be mixed.

With the microcapsules according to the invention or according to a method according to the invention Microcapsules produced or the adhesives according to the invention can be in Depending on the chosen adhesive system, glue different substrates.

The present invention therefore also relates to a method for bonding at least two substrates, in which on the surface of at least one substrate Adhesive, at least containing a microcapsule, consisting of a capsule shell and a capsule content, the capsule content being at least one non-water-soluble Compound with at least two against isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups reactive functional groups X has and the capsule shell by reaction of functional groups X des Capsule content with a water-emulsifiable compound, which is compared to the functional groups X of the capsule content has reactive functional groups Z, is created, is applied to at least one substrate surface, and the adhesive is heated or irradiated before, during or after assembly of the substrates.

In principle, all are suitable as substrates in the context of the present invention Materials made with the help of an adhesive containing the above microcapsules has glued. For example, wood, metal, paper, Glass, for example quartz glass, plastics such as polyester, polyoxymethylene (POM), Polyalkyl acrylates or methacrylates such as polymethyl methacrylate or polymethyl acrylate, Polyethylene and the like.

The method according to the invention requires heating or irradiation of the Adhesive containing microcapsules with high-energy radiation.

If the method according to the invention is carried out in detail that the bonding by heating the glue is achieved, so should the heating for example over a period of about 5 to about 5 hundred seconds, for example, about 30 to about 50 seconds. The one to achieve sufficient gluing required time for appropriate heating is also dependent on the temperature reached during the heating process. In Depending on the substrate to be bonded, temperatures are in a range from about 70 to about 150 ° C, especially about 80 to about 120 ° C, for example about 90 to about 110 ° C, proven.

Within the scope of the present invention, radiation is considered high-energy radiation with a wavelength of 200 to 700 nm, in particular from 220 to 650 nm.

Also for irradiating those coated with an adhesive according to the invention For example, substrates are suitable for microwaves. The adhesive can harden be carried out, for example, in a commercially available microwave oven. Suitable irradiation times vary between about 2 seconds and about 10 minutes, preferably curing within about 0.5 to about 3 minutes carried out.

The energy density prevailing during irradiation for the wavelength range from 200 to 700 nm, in particular from 200 to 650 nm, on the irradiated material should be at least about 0.2 J / cm ² . For example, energy densities of approximately 0.5 to approximately 25 J / cm ² or approximately 1 to approximately 15 J / cm ² , for example approximately 3 to approximately 11 or approximately 5 to approximately 8 J / cm ^2, are suitable.

The heating provided in the process according to the invention or Radiation with high-energy radiation can basically be before, during or after the The substrates are joined together. If the radiation before assembling the substrates takes place, the adhesive used should be set such that after the opening of the microcapsules still a sufficient open time for the adhesive remains, so that the substrates are joined together and, if necessary, subsequently Correction can be done. A suitable open time can, depending on the type of bonded Substrates and the associated processing method, about 1 s up to about 1 h.

If the adhesive is heated or irradiated during the assembly of the substrates is, it means that between heating or irradiation of the adhesive and the actual assembly of the substrates is less than is about 1 s. A corresponding energy source can be used in this process variant For example, be arranged so that the adhesive and substrate both before and after are put together with a corresponding radiation dose. For however, the effectiveness of high energy radiation after assembly is required that at least that between the adhesive layer and the radiation source The substrate for the applied high-energy radiation is permeable.

The same applies analogously to the third process variant, in which the heating or Irradiation with high-energy radiation only after joining the substrates he follows. Here it is necessary that at least that facing the radiation source Substrate is permeable to the high-energy radiation used.

In the context of a preferred embodiment of the present invention, the Carrying out the method according to the invention a combination of heating and Microwave radiation used. This is the one applied to the substrate Glue preferably warmed first and then for a short time, for example for a period of about 0.5 to about 3 minutes Microwave radiation with a power of approximately 200 to approximately 1500, in particular approximately 500 irradiated to about 900 watts.

The present invention also relates to the use of a Microcapsule according to the invention or one according to a method according to the invention manufactured microcapsule for the production of adhesives.

Another object of the present invention is the use of a Microcapsule according to the invention for bonding substrates.

The invention is explained in more detail below by examples.

Examples Production of the microcapsules according to the invention and measured storage stability. example 1

4-aminodiphenylamine (ground, 5 µm)

demineralised water

Liofol UK 5888-21 (Henkel, Poly-HDI, M 500)

THE 331 P Epoxy Resin (DOW, epoxy resin, MW 700 g / mol)

18.4 g of aminodiphenylamine were combined with 200 g of demineralized water 500 ml three-neck flask dispersed at 500 rpm. 4.7 g of UK 5888 were added to 35 g of the. water emulsified and then within 10 'of the dispersion of aminodiphenylamine in water dropwise. The mixture was then stirred for a further 4 h. The product was suctioned off with the. Washed water and dried in a drying cabinet.

21.8 g of a brown powder (94%) with a particle size of 5 μm were obtained.

Checking the open time

1.2 g of the capsules from Example 1 were added to 6 g of DER 331 P and mixed thoroughly. After 12 days there was only a slight increase in viscosity, the open time is practically unlimited with closed capsules (> 1 year). Example 2 19.8 g bis- (4-aminophenyl) methane (ground, 3 µm)
200 g demineralized water
14 g UK 5888-21 + 25 g dem. water

Same procedure as in example 1.

There were 29.3 g of white powder (87%) with an average particle size obtained from 3 µm.

Checking the open time

1.7 g of microcapsules from Example 2 were added to 5.7 g of DER 331 P and mixed thoroughly. After 11 days there was only a slight increase in viscosity, the open time is practically unlimited when the capsules are closed (> 1 year). Example 3 10.0 g of 1,12-diaminododecane (ground, 5 µm)
200 g of. water
4.7 g UK 5888-21 + 35 g dem. water

Same procedure as in example 1.

14.0 g of white powder (95%) with a particle size of 5 μm were obtained.

Checking the open time

1.5 g of capsules were added to 5.7 g of DER 331 P and mixed thoroughly. After 13 days there was only a slight increase in viscosity, the open time is practically unlimited when the capsules are closed (> 1 year). Example 4 15.0 g bis- (4-aminocyclohexyl) methane (ground, 5 µm)
300 g of. water
7.0 g UK 5888-21 + 60 g dem. water
Same procedure as in example 1.

16.3 g of brown powder (74%) were obtained.

Checking the open time

1.5 g of capsules were added to 5.4 g of DER 331 P and mixed thoroughly. To There was only a slight increase in viscosity over 30 days, which is open time with closed capsules practically unlimited (> 1 year).

Example 5

The adhesives produced according to Examples 1 to 4 were used to bond Test specimens made of aluminum (100 × 25 × 1.5 mm) are used. For this purpose, the test specimens degreased with acetone and an adhesive surface of 25 × 10 mm for the adhesive application marked. A test specimen was coated with the adhesive and on the marked area joined with a second test specimen. The gluing was fixed with brackets. The adhesive bond was in a forced air drying cabinet hardened for 20 minutes at 150 ° C. After one day of storage at room temperature were the glued test specimens with a tearing machine (company Zwick) at a Torn speed of 15 mm / minute.

The encapsulated diamines according to Examples 1 to 4 gave tensile shear strengths of 7.8, 9.3, 8.1 and 8.2 N / mm ^2, respectively. Example 6 The adhesives produced according to Examples 1 to 4 were each filled into a glass bottle with a content of 10 ml. The individual samples were positioned in the center of the irradiation plate in a commercially available microwave device (Miele De Luxe M693, max. 700 W). After an irradiation period of 2 minutes at an output of 700 watts, the adhesive was completely cured in all four samples.

Claims (13)

1. microcapsule with a diameter of 0.1 to 20 microns, consisting of a Capsule shell and a capsule content, the capsule content at least one not water-soluble compound with at least two against isocyanate groups or Epoxy groups or carboxyl groups or activated carboxyl groups reactive has functional groups X, and the capsule shell by reaction of functional groups X of the capsule content with a water-emulsifiable Compound opposite the functional groups X of the capsule contents reactive functional groups Z has arisen. 2. Microcapsule according to claim 1, characterized in that the capsule shell Has wall thickness of at least 1 nm. 3. Microcapsule according to claim 1 or 2, characterized in that the functional groups X independently of one another for an amino group or OH group stand. 4. Microcapsule according to one of claims 1 to 3, characterized in that the Capsule shell by reaction of functional groups X of the capsule content with a water-emulsifiable isocyanate is formed. 5. Microcapsule according to one of claims 1 to 4, characterized in that the Capsule content contains an at least difunctional amine. 6. A method of manufacturing a microcapsule in which an aqueous dispersion a non-water-soluble compound with at least two opposite Isocyanate groups or epoxy groups or carboxyl groups or activated Functional groups X reactive with carboxyl groups in water emulsifiable compound which is functional group X of the Has capsule contents reactive functional groups Z is added. 7. The method according to claim 6, characterized in that the in water emulsifiable compound which is functional group X of the Has capsule contents reactive functional groups Z, the aqueous dispersion is added as an aqueous emulsion. 8. adhesive, at least containing a component A and a component B, wherein
Component A at least one microcapsule according to one of claims 1 to 6 or one microcapsule produced by a method according to one of claims 6 or 7, and
Component B contains at least one compound with at least two functional groups Y. 9. Adhesive according to claim 8, characterized in that the functional Groups Y are independently selected for a functional group the group consisting of isocyanates, epoxides, carboxylic acids, Carboxylic acid esters, carboxylic acid chlorides or carboxylic acid anhydrides are available. 10. Adhesive according to claim 8 or 9, characterized in that the Equivalent ratio of reactive functional groups X in component A. functional groups Y in component B is about 1: 100 to about 1: 1. 11. A method for producing an adhesive according to any one of claims 8 to 10, wherein a component A and a component B, wherein
Component A at least one microcapsule according to the invention, and
Component B contains at least one compound with at least two functional groups Y,
be mixed. 12. Method for bonding at least two substrates, in which the Surface of at least one substrate, an adhesive, at least containing one Microcapsule, consisting of a capsule shell and a capsule content, the Capsule contains at least one non-water-soluble compound with at least two towards isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups reactive functional groups X and the Capsule shell by reaction of functional groups X of the capsule content with a water emulsifiable compound that is functional Groups X of the capsule contents have reactive functional groups Z, developed is applied to at least one substrate surface and the adhesive is applied heated or irradiated during or after assembly of the substrates becomes. 13. Use of a microcapsule according to one of claims 1 to 5 or one according to one of claims 6 or 7 produced microcapsule for the production of Adhesives.