DE10139788A1 - Process for the production of microcapsules - Google Patents

Abstract

The invention relates to a method for the production of microcapsule. Said microcapsules comprise a coating and a content, wherein the content of the capsule includes at least one compound with at least two reactive functional groups X relative to the isocyanate groups or epoxide groups or carboxyl groups or activated carboxyl groups or a compound with at least two isocyanate groups or epoxide groups or carboxyl groups or activated carboxyl groups.

Description

The present invention relates to a method for producing microcapsules. The Microcapsules consist of a capsule shell and a capsule content, the Capsule contents at least one compound with at least two opposite Isocyanate groups or epoxy groups or carboxyl groups or activated Carboxyl reactive functional groups X or a compound with at least two isocyanate groups or epoxy groups or carboxyl groups or activated Has carboxyl groups.

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 1K However, surface coating agents called systems often require very high ones Temperatures to harden. 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 are small in diameter, but their manufacture is consuming.

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, even when particularly thin films are bonded, is essentially flat, result in a transparent adhesive surface. However, this is when using Microcapsule systems whose microcapsules have a diameter of more than about 20 µm exhibit, difficult to realize. Even the bonding of surfaces that Bumps such as gaps or holes have a diameter in the µm range, can be glued with such systems only poorly, since the to harden the Because of their large diameter, microcapsules require such gaps or cannot penetrate holes. This is how it hardens in such gaps or Holes in the adhesive are not or only too slowly.

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 Interfacial polymerization used has further disadvantages 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 far it has been assumed that breaking up such agglomerates into a Damage to the capsule wall results, causing contact between the capsule contents and a reactive matrix surrounding the capsule is no longer interrupted and thus one premature reaction between matrix and capsule content can take place. Such however, early response is undesirable.

There was therefore a need for a method of manufacturing microcapsules for Application in adhesive systems that have the smallest possible diameter and a have as narrow a particle size distribution as possible, but their production 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 a Process for the production of such microcapsules and in the provision of a Adhesive containing microcapsules made by such a method.

The objects on which the invention is based are achieved by a method for Manufacture of microcapsules and adhesives, as described in the text below are described.

The present invention therefore relates to a method for producing Microcapsules in which a solid capsule content is covered with a capsule shell and so Microcapsules obtained are then ground, with a capsule content Compound with at least two against isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups reactive functional groups X or a compound with at least two isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups is used.

For the sake of simplicity, the text below after the Microcapsules produced according to the inventive method as "inventive Microcapsules ".

In the context of the present invention, a “microcapsule” is a structure understood that has a capsule content and at least one capsule shell. Such In the context of the present invention, “microcapsule” has a diameter of less than about 50 µm, for example less than 20 µm, less than 15 µm or in particular less than 10 microns. In a preferred embodiment of the present invention exhibit at least about 95% of the invention Microcapsules have a diameter of less than about 10 microns. The specified Diameters relate to measured values for particle diameters as they are usual methods for determining particle diameters are available. suitable Measuring methods are, for example, sieving methods, light scattering, electron microscopy, Light microscopy, scanning electron microscopy or sedimentation processes. This The definition does not conflict with the fact that two or more microcapsules form one Aggregate. The decisive factor in the present case is Particle size of the individual microcapsules participating in the aggregate.

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 ( _MW ), as determined by GPC under suitable conditions. for example based on a polystyrene standard.

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 activated esters or acid chlorides.

Suitable functional groups X are, for example, OH, NH ₂ , NHR ¹ or SH 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 have, for example, only one type of functional group X, d. that is, all of them a functional group X located in a molecule of the corresponding compound are identical. However, it is also possible within the scope of the present invention that the capsule content contains a compound which has two or more functional groups X having at least two of the functional groups X of a compound are different. For example, it is possible within the scope of the present Invention to use as a capsule content a compound, for example, at least has an OH group and at least one 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.

Furthermore, for example, aliphatic amines with more than two amino groups are like Diethylene triamine, triethylene tetramine, tetraethylene pentamine or diethylaminopropylamine suitable.

Aromatic amines such as m-phenylenediamine are also suitable. Diaminodiphenylmethane, diaminodiphenylsulfone, bisaminomethyldiphenylenemethane, 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, Dicyandiamides, 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: isophorone diamine, m-xylylenediamine, 2,2,4-trimethylhexamethylene diamine, 4,4'- Trimethylene dipiperidine, 1,3-di (4-piperidyl) propane, 1,6-diaminohexane, 1,7- Diaminoheptane, 1,11-diaminodecane, 1,12-diaminododecane, 4,4-diaminodicyclohexylmethane, 1,4-diazabicyclo [2.2.2] octane (DABCO) and polymeric di- or Polyamines such as polyesters, polyurethanes or amino groups Polyethers, particularly those sold under the tradename Jeffamine® by Huntsman Corp. available polyalkylene glycols bearing amino groups.

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.

Instead of the compounds mentioned with at least one functional group X can a microcapsule according to the invention one or more compounds with at least two Isocyanate groups or epoxy groups or carboxyl groups or activated Have carboxyl groups.

Suitable compounds with at least two isocyanate groups are, for example Compounds such as 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), Cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and mixtures of two or more of them, 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.

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.

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 two or more epoxy groups. Such connections can be for example by reacting polyhydric phenols such as bisphenol A, bisphenol F, catechol or resorcinol or of polyhydric 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 of hydroxycarboxylic acids such as p- Get hydroxybenzoic acid or 2-hydroxynaphthenic acid with epichlorohydrin. Also suitable as compounds bearing at least two epoxy groups are the Reaction products of amines such as 4,4'-diaminodiphenylmethane, m-aminophenol and the like, for example the reaction products already as capsule content above called amines, with epichlorohydrin.

Suitable compounds which carry carboxyl groups or activated carboxyl groups in particular the low molecular weight di- or polycarboxylic acids, if appropriate in their activated form as indicated above. Such di- or 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 or trimer fatty acid or mixtures of two or more of them suitable. If appropriate, a microcapsule according to the invention can still minor amounts of monofunctional carboxylic acids, in particular monofunctional fatty acids with 6 to 44 carbon atoms.

In addition to the above-mentioned compounds with functional groups X or one or several compounds with at least two isocyanate groups or epoxy groups or The capsule contents can contain further carboxyl groups or activated carboxyl groups Have additives. These include, for example, catalysts, photosensitizers, Plasticizers, antioxidants, stabilizers, dyes, fragrances, pigments and like.

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, 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 include above all 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 for one Oxygen, sulfur or nitrogen compound or a mixture of two or more of them. 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 preferred class of compounds are the dialkyl-tin (IV) carboxylates (Z = O-CO-R '). The carboxylic acids have 2, preferably at least 10, in particular 14 up to 32 carbon atoms. Dicarboxylic acids can also be used. As acids are for example adipic acid, maleic acid, fumaric acid, terephthalic acid, phenylacetic acid, Benzoic acid, acetic acid, propionic acid and in particular caprylic, capric, lauric, Suitable for myristic, palmitic and stearic acid. For example, are particularly suitable Dibutyltin diacetate and dilaurate and dioctyltin diacetate and dilaurate.

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), Octylzinntris- (thioglycolic acid-2-ethyl-hexyl) Dioctyltin bis (thioethylene glycol 2-ethylhexoate), 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 thiolatoessigsäure) 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 other (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 be used as an additive or a photosensitizer contain a mixture of two or more photosensitizers. Under a "Photosensitizer" in the context of the present invention is a compound understood, which transfers the radiation energy it absorbs to molecules, which do not themselves absorb the radiated energy or the energy absorbed by it Radiant energy converted directly into heat.

Suitable photosensitizers are, for example, benzophenone, Michler's ketone, 2- Acetonaphthon, Chrysen, Fluorenon, Benzil, 1,2-Benzanthrazen, Acridin, Anthrazen, Thioxanthone or fluorenone or compounds sold under the name Thinuvin® (Manufacturer: Ciba Geigy) are commercially available. Also suitable are triazines, Benzotriazoles and benzophenone derivatives, as described, for example, in WO 98/03489 are described, UV absorbers as described, for example, in EP-A 0 893 119, EP-A 1 032 563, Kunststoffe (1999), 89 (7), 87-90 or Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2000 Electronic Release, PAINTS AND COATINGS - Paint additives 5.7 Light Stabilizers or Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2000 Electronic Release, Photochemistry, Table 8. On the in the corresponding publications called photoactive compounds expressly referred. The compounds are considered part of the disclosure of the considered the present text.

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.

In the context of a preferred embodiment of the present invention, a Microcapsule according to the invention as capsule content a polyamine or several polyamines or one or more polyhydroxy compounds.

In the context of a further preferred embodiment of the present invention contains a microcapsule according to the invention up to about 10% by weight, in particular about 0.1 up to about 8 or about 0.5 to about 5 or about 1 to about 3% by weight of additives.

A microcapsule according to the invention can be used within the scope of the present invention basically have any capsule shell. The capsule shell serves in the present case Case solely for the purpose of the capsule contents against one within the scope of a Application of the capsule to separate the capsule enclosing matrix so that none Mixing of the capsule content with the matrix surrounding the capsule takes place. A In addition, the capsule shell is essentially intended to withstand external influences Temperature fluctuations, shocks or light radiation under transportation or Storage conditions be essentially insensitive, so that a long as possible Storage stability is guaranteed.

Within the scope of the present invention, microcapsules are used to produce chemical microencapsulation processes used. Here is a wall formation monomeric starting materials by condensation or addition reaction between Capsule content and the compound forming the capsule shell preferred.

In the process of the invention, the solids to be encapsulated with at least two functional groups X in to a desired particle size ground form finely dispersed in a continuous phase, after which the a continuous phase a compound is added, which with the on the surface of the functional groups X to be encapsulated with deactivation of the functional groups X react. Systems suitable for such a method are, for example, the systems amine / isocyanate or amine / acid chloride, the amine is the compound to be encapsulated. In this case, the continuous phase no reactive functional groups X on or in the Functional groups X present in the continuous phase have a lower number Reactivity with the monomers used for encapsulation than that functional groups X of the material to be encapsulated.

If, for example, as provided in the context of the present invention, a compound with an OH, NH ₂ , NHR or SH group or a mixture of two or more such compounds is to form the capsule content, these compounds can be used in a corresponding manner be submitted to the continuous phase and dispersed.

You can then use one of the substances mentioned as capsule contents reactive compound a deactivation shell or a polymer shell around the Capsule contents are generated.

The problem here, however, has usually turned out to be that Encapsulated particles tend to form agglomerates during encapsulation. However, these agglomerates change the grain spectrum of the microcapsules to larger ones Particle diameters, as a result of which those already described at the beginning of this text Disadvantages occur. However, it has now become within the scope of the present invention pointed out that the use of certain materials for the capsule shell in the context of the inventive method a breakup of such agglomerates by simple Grinding of the microcapsules enables without the microcapsules subsequently Adhesive applications for undesired, premature curing of the Lead adhesive.

A particularly suitable procedure is, for example, that the Capsule content is dispersed in a solvent that does not dissolve the capsule content, and then, for example, a mono-, di- or polyisocyanate, for example one of the mono-, di- or polyisocyanates described above, or a mono-, di- or Polyacid chloride, for example a di- or polyacid chloride one of the above described di- or polycarboxylic acids is added to the dispersion.

A representation of various encapsulation processes can be found, for example, in Angewandte Chemie, 87, born 1975, No. 16, 556 to 567, EP-A 0 547 379 or EP-A 0 193 068, the parts of the disclosure relating to the encapsulation process as Be considered part of the disclosure of the present text.

In the context of the present invention are suitable for producing the capsule shells for example essentially monomolecular layers of a deactivating agent. In the context of the present invention, compounds are used as deactivating agents designated, which with the reactive functional groups of the capsule contents under Can react to form a covalent bond. A deactivator is encased the capsule content such that the reactive on the surface of the capsule content functional groups are deactivated by the deactivation means and thus one Reaction with a reactive matrix surrounding the capsule are no longer accessible. The capsule contents can only react with a reactive matrix when the capsule is destroyed by external influence. Suitable deactivators are preferred monofunctional with regard to the reactive groups of the capsule content.

If a to produce the capsule shell within the scope of the present invention polyfunctional compound, for example a polyfunctional isocyanate or a polyfunctional epoxy is used, it is within the scope of the present invention preferred if after the reaction of the capsule content with that forming the capsule shell Compound opposite the functional groups of the capsule shell Compound monofunctional compound is added to the reaction mixture to unreacted areas in the capsule shell to deactivate. Suitable monofunctional Compounds are, for example, monofunctional amines or monofunctional Alcohols.

In a preferred embodiment of the present invention Generation of a capsule shell a monofunctional isocyanate as a deactivating agent used. Suitable monofunctional isocyanates are, for example, monofunctional Isocyanate prepolymers such as those sold under the name Trixene-ASF by the company Baxends (Brenntag) are available, such as stearyl isocyanate as technical mixture of octadecyl isocyanate and hexadecyl isocyanate (65:30) from Bayer is sold, phenyl isocyanate, dimethyl-m-isopropenylbenzyl isocyanate or tosyl isocyanate or mixtures of two or more thereof.

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 a deactivating agent, for example at least about 10 nm on.

In the context of the present invention, the microcapsules can also be used as a capsule shell have a combination of several types of envelopes, in which case usually a first envelope was generated by a deactivating means and an or several more shells contain at least one polymer. As part of the Grinding of the microcapsules according to the method according to the invention takes place either after application of the first capsule shell by reaction of the capsule contents with the deactivation agent and before the subsequent application of a further capsule shell or after such an application of another capsule shell.

For the application of one or more additional capsule shells are suitable within the present invention in particular mechanical-physical Microencapsulation. 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 a film-forming polymer is dissolved in the spray drop surrounding the core material particles. When the volatile components evaporate, this solution shrinks to a pure polymer shell, which tightly encloses the core material. Such capsules fall as free-flowing, dry Powder. In the context of a preferred embodiment of the present invention spray drying is used to produce the microcapsules according to the invention.

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.

Suitable as part of the capsule shell in the context of the present invention 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, especially hydroxyethyl cellulose or their mixed ethers, such as methylhydroxyethyl or hydroxypropyl cellulose, Carboxymethylhydroxyethyl cellulose or ethyl hydroxyethyl cellulose or a mixture of two or more of the polymers mentioned. Polymers are also suitable, for example themselves by polymerizations of vinyl acetate and subsequent partial or Allow part or all of the acetate groups to be completely saponified. For this include in particular polyvinyl alcohols which still contain about 1 to about 70% acetate groups exhibit.

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 used as a component of the capsule shell, a styrene / vinyl acetate copolymer, the At least 60%, preferably at least 80% or 90% of vinyl acetate units are saponified. If polyvinyl alcohol is used as part of the capsule shell, so polyvinyl alcohol with a degree of saponification of approximately 70 to is particularly suitable about 90%.

The sulfonic acid derivatives of the abovementioned compounds are also suitable, for example Na polystyrene sulfonate with a molecular weight (M _w ) of about 50,000 to about 100,000.

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 preferred embodiment are polymer mixtures as the material for the capsule shell used by the polymerization of styrene in the presence of a hydrophilic Polymers, for example in the presence of cellulose or in the presence of a Cellulose ether or in the presence of polyvinyl alcohol.

The polymers contained in the capsule shell have a molecular weight of at least about 1000, preferably at least about 3000. As part of a preferred embodiment of the present invention is the molecular weight of the polymers contained in the capsule shell at at least about 5000, for example at least about 10,000. The upper limit of the molecular weight in the capsule shell contained polymers is about 1,000,000, but preferably less. suitable The upper limit for corresponding molecular weights is, for example, 200,000, 100,000 or about 50,000. If, for example, a cellulose ether is part of the capsule shell is used, then has a molecular weight of about 15,000 to about 40,000 proven. If, for example, a component of the capsule shell is a polyvinyl alcohol is used, the molecular weight should be about 10,000 to about 35,000.

The capsule shell can contain, for example, one of the abovementioned polymers, it is however, within the scope of the present invention it is also possible for the capsule shell to have two or contains more of the polymers mentioned. The proportion of water soluble or water-dispersible polymers on the capsule shell is at least about 30% by weight or at least about 40% by weight. In a preferred embodiment of the The present invention is the proportion of water-soluble or water-dispersible Polymers on the capsule shell at least about 50% by weight or 60% by weight, for example at least about 70% by weight, 80% by weight, 90% by weight or even 100% by weight %.

Basically all spray drying processes known to the person skilled in the art are suitable for Production of the other cladding layers suitable. In a spray drying process is the aqueous solution or dispersion, which are the components of the invention Contains microcapsule, sprayed together with a hot air stream, the aqueous Evaporate phase or all components volatile in the air flow.

In order to achieve the most complete possible wrapping, it is advantageous if the Capsule content, d. that is, the one intended for a further wrapping, with a first one Capsule shell made of a deactivating agent-coated microcapsule in which Spray drying used dispersion is in the finest possible distribution. Therefore, it is advantageous in the context of the present invention if the after a Microcapsules produced according to the invention already after the first Encapsulation step, d. that is, after reacting with the deactivator to which desired size can be ground.

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 dispersion of microcapsules subjected to spray drying contains about 0.1 to about 40% by weight, in particular about 0.5 to about 30% by weight of a water-soluble or water-dispersible polymers or a mixture of two or more of such Polymers. If, for example, a cellulose ether or a mixture of two or more cellulose ethers is used, is within the scope of a preferred Embodiment of the present invention, the proportion of cellulose ether or Cellulose ethers in the dispersion of microcapsules used for spray drying 0.5 to about 5, especially about 1 to about 4 wt .-%. When spray drying used dispersion polyvinyl alcohol or a polyvinyl alcohol containing Contains copolymer or a mixture of two or more such polymers, is the proportion of these polymers in the total dispersion used for spray drying about 5 to about 40, in particular about 10 to about 30% by weight.

Other methods suitable for producing the microcapsules according to the invention are for example the multi-component nozzle process or the coating in the fluidized bed.

In the context of the method according to the invention, the on one of the above described types produced microcapsules following their manufacture one Subjected to grinding. It is provided according to the invention that the microcapsules contains it in the wet or dry state subjected to such grinding become. However, the microcapsules according to the invention are preferably dry Condition ground.

In a preferred embodiment of the present invention Grinding used microcapsules that have only one capsule shell, d. i.e. with only one height layer are covered. However, it is within the scope of the present Invention also possible to grind microcapsules that have two or more stories exhibit.

In principle, any one can be used for grinding within the scope of the present invention Apparatus are used, the size of particles up to about 5 µm or less is suitable. Is particularly preferred in the context of the present Invention of the use of type 4142 mills, type 71 ball mill from Hormuth-Vetter, Alpine air jet mill or Chrispo Jetmill type LU / MC 100 IR.

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

wobei die funktionellen Gruppen Y mit den funktionellen Gruppen X unter Ausbildung einer kovalenten Bindung reagieren können. 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, and
• - Component B contains at least one compound with at least two functional groups Y, and

wherein the functional groups Y can react with the functional groups X to form a covalent bond.

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 react to form a covalent bond can. In particular, the functional group Y represents a functional 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, butylene glycol 1,4 or 1,3, hexanediol 1,6, octanediol 1,8, 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, 1,2-butanetriol, 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 suitable. If necessary, minor amounts of monofunctional fatty acids be present in the reaction mixture.

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.

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.

Three or are also suitable as isocyanates for the purposes of the present invention 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 Trüsocyanurate.

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.

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 or the ratio of functional groups X to functional groups Y in Component B about 1: 100 to about 1: 1. Under the term "equivalent ratio" is in the context of the present invention, the molar ratio of functional groups X understood to functional groups Y.

• - Komponente A mindestens eine erfindungsgemäße Mikrokapsel, und
• - Komponente B mindestens eine Verbindung mit mindestens zwei funktionellen Gruppen Y, wobei die funktionellen Gruppen Y mit den funktionellen Gruppen X unter Ausbildung einer kovalenten Bindung reagieren können,

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

• - Component A at least one microcapsule according to the invention, and
• Component B at least one compound with at least two functional groups Y, where the functional groups Y can react with the functional groups X to form a covalent bond,

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 inventive method is carried out so that the Bonding is achieved by heating the adhesive, 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 proven from about 70 to about 200 ° C, in particular about 80 to about 160 ° C.

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, John from 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 Encapsulation with phenyl isocyanate example 1

4-aminodiphenylamine (ADPA, ground, 5 µm)

cyclohexane

Phenyl isocyanate (Fluka, M 119)

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

92 g of ADPA were mixed with 400 g of cyclohexane in a 1L three-necked flask at 500 rpm dispersed. 27.6 g of phenyl isocyanate were dissolved in 60 g of cyclohexane and then in 2 hours added dropwise, followed by stirring for a further 4 h. The reaction product was suction filtered, washed with cyclohexane and dried in a drying cabinet. There were Obtained 115 g of gray powder (96%) with a particle size of 10-25 µm. Grinding in a mill produced a particle size of 5 µm.

1.3 g of capsules were added to 6 g of DER 331P and mixed thoroughly. After 12 days the viscosity had risen only slightly, the storage stability is practically unlimited. Example 2 11.6 g 1,6-diaminohexane (ground, <10 µm)
200 g n-octane
6.0 g phenyl isocyanate + 30 g n-octane
Same procedure as in example 1

8.3 g of white powder (47%) with a particle size of 1-150 μm were obtained. Remilling in a mill produced a particle size of 5 µm.

1.5 g capsules were added to 9.8 g DER 331P and mixed thoroughly. After 14 days the viscosity increased only slightly. Example 3 20 g of bis (4-aminocyclohexyl) methane (ground, 5 µm)
200 g n-octane
11.0 g phenyl isocyanate + 30 g n-octane
Same procedure as in example 1.

25.7 g of white powder (83%) were obtained. Grind again in a mill produces a particle size of 5 µm.

1.5 g of capsules were added to 5.4 g of DER 331P and mixed thoroughly. After 22 days the viscosity had increased only slightly. Example 4 10.0 g of 1,12-diaminododecane (ground, 5 µm)
200 g n-octane
3.0 g phenyl isocyanate + 30 g n-octane
Same procedure as in example 1.

11.0 g of white powder (85%) with a particle size of 5-200 μm are obtained. Re-grinding in a mill produces a particle size of 5 µm.

1.3 g capsules are added to 5.7 g DER 331P and mixed thoroughly. After 20 Days the viscosity had only increased slightly.

Example 5

DER 331P (epoxy resin, Dow company) was each made with an encapsulated diamine Examples 1 to 4 in a molar ratio of 3 to 1 in an aluminum shell stirred. Test specimens made of aluminum (100 × 25 × 1.5 mm) were degreased with acetone and marked an adhesive surface of 25 × 10 mm for the adhesive application. A test specimen was made coated with the adhesive and a second on the marked surface Test specimen assembled. The bond was fixed with clips. The Adhesive composite was in a forced air drying cabinet for 20 minutes at 150 ° C hardened. After storage for one day at room temperature, the bonded Test specimen with a tearing machine (Zwick company) at a speed of 15 mm / minute torn.

The encapsulated diamines according to Examples 1 to 4 gave tensile shear strengths of 2.2, 2.8, 8.5 and 8.0 N / mm ^2, respectively.

Example 6

The adhesives produced according to Example 5 were in glass bottles with a content filled by 10 ml. The individual samples were each in a commercially available Microwave (Miele De Luxe M693, max. 700 W) positioned in the middle. To The adhesive was an irradiation period of 2 minutes at an output of 700 watts fully cured on all four samples.

Claims (11)

1. Process for the production of microcapsules, in which a solid capsule content with a capsule shell and then the microcapsules thus obtained are ground, the capsule content being a compound with at least two versus two versus isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups reactive functional Groups X or a compound with at least two isocyanate groups or Epoxy groups or carboxyl groups or activated carboxyl groups used becomes. 2. The method according to claim 1, characterized in that the capsule shell from compared to the functional groups X of the capsule content monofunctional Connections is formed. 3. The method according to claim 1 or 2, characterized in that as the capsule content an at least difunctional amine is used. 4. microcapsule, obtainable by a process according to any one of claims 1 to 3. 5. adhesive, at least containing a component A and a component B, wherein
Component A at least one microcapsule produced by a process according to the invention, and
Component B contains at least one compound with at least two functional groups Y or at least one compound with at least two functional groups Y and at least one compound with at least two functional groups X, and
wherein the functional groups Y can react with the functional groups X to form a covalent bond. 6. Adhesive according to claim 5, 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. 7. Adhesive according to claim 5 or 6, 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. 8. A method for producing an adhesive according to any one of claims 5 to 7, wherein a component A and a component B, wherein
as component A at least one microcapsule produced by a process according to the invention, and
contains as component B at least one compound with at least two functional groups Y or at least one compound with at least two functional groups Y and at least one compound with at least two functional groups X and wherein the functional groups Y react with the functional groups X to form a covalent bond can,
be mixed. 9. Method for bonding at least two substrates, in which on the Surface of at least one substrate, an adhesive, at least containing one Microcapsule produced according to one of Claims 1 to 3, to at least one Substrate surface is applied, and the adhesive before, during or after assembling the substrates heated or with high-energy radiation is irradiated, in the case of irradiation with high-energy radiation after assembling the substrates at least one of the substrates for the high-energy radiation must be at least partially permeable. 10. Adhesive containing at least two components A and B, wherein
as component A at least one microcapsule produced according to one of claims 1 to 3 and
component B contains at least one compound with at least two functional groups Y or at least one compound with at least two functional groups Y and at least one compound with at least two functional groups X and at least one photosensitizer,
wherein the functional groups Y can react with the functional groups X to form a covalent bond. 11. Use of a microcapsule produced according to one of claims 1 to 3 Manufacture of adhesives.