DE10062641A1 - Photosensitive microcapsules, processes for their production and their use in adhesives - Google Patents

Abstract

The invention relates to a photosensitive microcapsule comprised of a capsule enclosure and of a capsule contents. The capsule contents comprise at least one compound having at least two functional groups X, which react with isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups, or the capsule contents comprise a compound having at least two isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups. In addition, the capsule enclosure or the capsule contents or both contain(s) a photosensitizer. The invention also relates to adhesives that contain microcapsules, to methods for adhering substances, and to the use of microcapsules of this type in adhesives.

Description

The present invention relates to a photosensitive microcapsule consisting of a Capsule shell and a capsule content, the capsule content at least one 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 Has carboxyl groups or activated carboxyl groups and the capsule shell or Contains capsule content or both contains a photosensitizer. Furthermore, the Present invention Adhesives containing microcapsules, methods of adhesive bonding of 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 with the formation of covalent compounds and thus a hardening of 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. However, this limits the use of such 1K systems to the extent that certain, especially 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, prior to use, they require a mixing process in which defined Weighed quantities of the two components mixed 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 need 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 servings 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 are described that 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. An opening of the Microcapsules described by high-energy radiation is not in the document described.

The microcapsule systems known to date from the prior art have in Various disadvantages with regard to use in adhesives. Problematic basically has an effect on all thermally opening microcapsules Sticking out the fact that thermally sensitive substrates are not included Adhesives can be glued, the thermally opening microcapsules contain, because to open these capsules always substrate, adhesive and microcapsules need to be heated.

There was therefore a need for two components containing reactive components 1-component systems that are suitable for surface coating, preferably as an adhesive, being one of the reactive components or a the reaction between the reactive Components at a certain temperature triggering catalyst in encapsulated Form as a microcapsule is present, such a microcapsule by high-energy Radiation can be opened while releasing its contents.

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 and in the provision of a method for bonding substrates in which a 1K Adhesive using high-energy radiation to carry out the bonding is used.  

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

A first object of the present invention is therefore a photosensitive Microcapsule, consisting of a capsule shell and a capsule content, the Capsule shell at least one polymer with a molecular weight of more than 1000 and the capsule contents face at least one compound with at least two 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 Carboxyl groups or a catalyst that has a reaction between opposite Isocyanate groups or epoxy groups or carboxyl groups or activated Functional groups X reactive to carboxyl groups and isocyanate groups or Catalyzes epoxy groups or carboxyl groups or activated carboxyl groups, and the capsule shell or capsule contents or both a photosensitizer contains.

In the context of the present invention, a “microcapsule” is a structure understood that has a capsule content and a capsule shell. Such In the context of the present invention, “microcapsule” has a diameter of less than about 100 µm, for example less than 50 µm, less than 30 µm or less than 10 µm. In the context of a preferred embodiment of the present The invention has at least about 95% of the microcapsules according to the invention Diameter of less than about 30 microns. Obtain the specified diameters refer to measured values for particle diameters such as those used by conventional methods Determination 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.

A microcapsule according to the invention can be used in the context of the present invention as Capsule morphology have a typical capsule-like structure, in which a essentially closed casing made of casing material is essentially homogeneous Encloses core as capsule content. However, it is also possible according to the invention that a Microcapsule according to the invention has a shell which has an inhomogeneous core encloses. An "inhomogeneous core" means the finding that the Capsule content is present in several domains inside the capsule, i.e. several areas with capsule content spatially separated from one another by shell material within the Microcapsule present.

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 groups 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 at least one compound carries at least one amino group as functional group X. Suitable amines are for example aliphatic amines such as ethylenediamine, diethylenetriamine, Triethylene tetramine, tetraethylene pentamine or diethylaminopropylamine.

In the context of a preferred embodiment of the present invention, a microcapsule according to the invention, however, compounds having at least one functional Group X, the high-energy radiation in a range from 200 nm to 700 nm, in particular in a range from approximately 220 to approximately 650 or approximately 230 nm to approximately 460 nm, absorb. This is particularly advantageous if a microcapsule in the Framework of the inventive method described in the further course of the text to be used for bonding substrates, since here, if necessary, on the Presence of a photosensitizer can be dispensed with.

Aromatic amines such as m-phenylenediamine, 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, terephthalic dihydrazide, 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-ethylimida zole, 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.

Furthermore, as amines in the context of the present invention are the following amines applicable: isophoronediamine, m-xylylenediamine, 2,2,4-trimethylhexamethylenediamine, 4,4'- Trimethylene dipiperidine, 1,3-di (4-piperidyl) propane, 1,6-diaminohexane, 1,7- Diaminoheptane, 1,11-diaminodecane, 1,12-diaminododecane, 4,4-diamino dicyclohexylmethane, 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 or 4,4'-diaminodiphenylmethane or their Mixture.

However, the microcapsules according to the invention can also be used in adhesive systems are used that already have a reactive binder system next to each other present reactive compounds included. Such binder systems can, for example, basically take at least two together Molecular weight increase reactive compounds, for example Epoxy compounds and polyols. The responsiveness of the However, the binder system is strong at the processing temperature of the adhesive system restricted so that essentially no reaction takes place. The reaction of such Binder systems can, however, be started by means of suitable catalysts or accelerate. Within the scope of such an embodiment of the present invention the capsule content of the microcapsules according to the invention contains a catalyst or a Mixture of two or more catalysts that control the reaction of the binder system and thus allow the adhesive to set.

Suitable catalysts are, for example, tertiary amines, for. B. Triethylamine, 1,4-diazabicyclo [2,2,2] octane (= DABCO) dimethylbenzylamine, bis- dimethylaminoethyl ether and bis-methylaminomethylphenol. 1- are particularly suitable  Methyl imidazole, 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 Dimorpholinodiethylether.

Organotin compounds can also be used as catalysts. This includes 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} S _n Z _3-n where n is a number from 0 to 2, R is 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. Z can also be a sulfur compound, ie 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 ¹ ). The carboxylic acids have 2, preferably at least 10, in particular 14 to 32, carbon atoms. Dicarboxylic acids can also be used. Suitable 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, 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 dioctylthiolate, dibutyltin bis (2-ethylhexyl thioglycolic acid), octyltin tris (thioglycolic acid 2-ethylhexyl ester), dioctyltin bis (thioethylene glycol 2-ethylhexo at), 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 other (α- Dicarbonyl compounds such as acetylacetone, dibenzoylmethane, benzoylacetone, acetoacetic acid acid ethyl ester, acetoacetic acid n-propyl ester, α, α'-diphenylacetoacetic acid ethyl ester and Dehydroacetessigsäure.

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 ethylene diisocyanate, 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 thereof, 1-isocyanato-3,3,5-trimethyl-5- isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 2,4- and 2,6-hexahydro tolylene diisocyanate, 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 from two or more of the diisocyanates mentioned.  

Three or more are also suitable as compounds with two or more isocyanate groups higher quality isocyanates, such as 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, manose, galactose, Dextrose, sorbitol or mannitol and their reaction products with ethylene oxide or Propylene oxide or its mixture 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 Reaction products of amines such as 4,4'-diaminodiphenylmethane, m-aminophenol and the like, for example the reaction products already as capsule content above amines, with epichlorohydrin.

Suitable compounds containing 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, acelaic acid, sebacic acid, phthalic acid, isophthalic acid, Terephthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, Hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylene tetrahydro phthalic 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, a microcapsule according to the invention contains at least one photosensitizer. Under a "photosensitizer" in the Understand the context of the present invention, a connection that the of it absorbed radiation energy transfers to molecules, which the radiated energy do not absorb themselves or the radiation energy they absorb directly into heat transforms.

Photosensitizers according to the invention can have, for example, one or more functional groups X, for example OH, NH ₂ or NHR ¹ groups. In this case, however, it is a prerequisite that in a microcapsule according to the invention there is at least one compound with at least one functional group X which has a greater reactivity than the functional group X am towards an isocyanate group or an epoxy group or a carboxyl group or an activated carboxyl group Photosensitizer with the greatest reactivity.

Suitable photosensitizers are, for example, benzophenone, Michler's ketone, 2- Acetonaphthon, Chrysen, Fluorenon, Benzil, 1,2-Benzanthrazen, Acridin, Anthrazen, Thioxanthone or fluorenone or compounds that are 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 referenced. The compounds are considered part of the disclosure of the considered the present text.  

In the context of a further embodiment of the invention, the capsule content can be in addition to a photosensitizer, for example a compound with functional groups X, as described above, or a mixture of two or more such compounds and a catalyst as described above, or a mixture of two or more of them Contain catalysts.

In addition to the above-mentioned compounds with functional groups X or one Catalyst or a mixture of a compound with functional groups X and a catalyst or a mixture of two or more compounds with functional groups X and a catalyst or a mixture of two or more Compounds with functional groups X and a mixture of two or more The capsule content of catalysts can also contain other 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 with a about 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 that 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.

The microcapsule according to the invention can, in addition to a photosensitizer, the above mentioned compounds individually or as a mixture of two or more of the included connection types. Under "connection types" within the scope of present invention in each case compounds having functional groups X, Compounds with epoxy, isocyanate, carboxyl or activated carboxyl groups or Understood catalysts. For example, a microcapsule according to the invention can be a Polyamine or a mixture of two or more different polyamines, one Polyhydroxy compound or a mixture of two or more different ones Polyhydroxy compounds or a mixture of one or more polyamines and contain 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 several polyhydroxy compounds.

In the context of a further preferred embodiment of the present invention contains a microcapsule according to the invention about 0.01 to about 10 wt .-%, in particular about 0.1 to about 8 or about 0.5 to about 5 or about 1 to about 3% by weight Photosensitizer.

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 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 such as Temperature fluctuations, shocks or light radiation under transportation or Storage conditions should be essentially insensitive, so that as long as possible Storage stability is guaranteed.

On the other hand, the capsule shell is said to contribute to a microcapsule according to the invention corresponding conditions, that is, in the case of insolation dosed as low as possible, high-energy radiation the capsule content as quickly as possible and without large Release energy expenditure.

In principle, therefore, all types of capsule walls are suitable within the scope of the present invention, as can be obtained by conventional encapsulation methods known from the prior art. Suitable capsule walls are, for example, conventional polymers with a molecular weight of more than about 1000 ( _MW ). Suitable polymers are, for example, polyamides such as nylon (all nylon types), polyureas, polyvinyl formal, polyethylene, polystyrene, polymers based on natural or modified polysaccharides such as cellulose, polymers as can be obtained by radical polymerization of ethylenically unsaturated compounds, polyesters, polycarbonates and like. The type of capsule wall polymer is essentially determined by the method of manufacturing the microcapsule.

Also suitable as capsule shells are, for example, essentially monomolecular Layers of a deactivator. As a means of deactivation within the present invention referred to compounds which are reactive with the functional Groups of the capsule contents can react to form a covalent bond. A deactivating agent envelops the capsule content such that the on the surface of the The reactive functional groups are contained in the capsule by the deactivating agent be deactivated and thus a reaction with a reactive surrounding the capsule Matrix are no longer accessible. The contents of the capsule can only be reactivated Matrix react when the capsule is destroyed by external influences. suitable  Deactivation agents are preferably monofunctional with regard to the reactive ones Groups of capsule contents.

In the context of the present invention, the microcapsules can also be used as a capsule shell have a combination of the two types of envelopes mentioned above, in which one In case a first envelope was usually generated by a deactivating means and one or contain several further shells at least one polymer.

Basically, mechanical and physical are in the production of microcapsules distinguish chemical processes. With the mechanical / physical processes encapsulate liquid and solid particles in the gas space. The chemical process work in the liquid phase, i.e. in emulsion or dispersion.

A first mechanical-physical microencapsulation process is, for example Spray drying. It is a very general process for microencapsulation, in which an emulsion or dispersion in a hot, inert Gas stream is atomized. In a continuous phase that also in the spray drops Surrounding core material particles, a film-forming polymer is dissolved. If the fleeting Evaporation parts, this solution shrinks to the pure polymer shell, which is the core material tightly encloses. Such capsules are obtained as a free-flowing, dry powder. in the Within the scope of a preferred embodiment of the present invention, Production of the microcapsules according to the invention uses spray drying.

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 disperse 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 on suitable polymers for example cellulose or cellulose ethers such as carboxymethyl cellulose, methyl cellu loose, ethyl cellulose, hydroxyalkyl cellulose, especially hydroxyethyl cellulose or their mixed ethers, such as methylhydroxyethyl or hydroxypropyl cellulose, carboxyme ethyl hydroxyethyl cellulose or ethyl hydroxyethyl cellulose or a mixture of two or more of the polymers mentioned. Also suitable are, for example, polymers that themselves by polymerizations of vinyl acetate and subsequent partial or Allow some 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 as block copolymers are used. 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%.  

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, for example 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 as 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 above-mentioned 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 polymer 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 %.

The microcapsules according to the invention can be dried by spray drying an aqueous Obtain solution or dispersion of the components forming the capsule.

Basically all spray drying processes known to the person skilled in the art are suitable for Production of the microcapsules according to the invention is suitable. At a Spray drying is the aqueous solution or dispersion that the Contains components of the microcapsule according to the invention, together with a hot one Airflow sprayed, the aqueous phase or all volatile in the airflow Evaporate components. This creates microcapsules in which the connection with at least two against isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl reactive functional groups X or a mixture of two or more such compounds or a catalyst or a mixture of two or more catalysts or a mixture of a compound with at least two towards isocyanate groups or epoxy groups or carboxyl groups or activated Carboxyl reactive groups X and a catalyst or a Mixture of two or more compounds with at least two opposite Isocyanate groups or epoxy groups or carboxyl groups or activated Carboxyl reactive groups X and a catalyst or a Mixture of two or more compounds with at least two opposite Isocyanate groups or epoxy groups or carboxyl groups or activated Carboxyl reactive functional groups X and a mixture of two or more catalysts than capsule content from the capsule shell, which is at least one water soluble or water dispersible polymer with a molecular weight of contains more than 3000, is essentially completely encased.  

In order to achieve a complete encapsulation of the capsule contents, it is advantageous if the capsule content in the dispersion used for spray drying in distribution is as fine as possible. In a preferred embodiment of the Present invention, the capsule content should be distributed such that the average maximum particle size of the capsule content Compounds at most about 10 to 15 microns, but preferably less. Under the average maximum particle size is within the present In the case of solids, the average particle size of the solid particles Roger that. If the capsule contents or at least parts of the capsule contents as a liquid is present, the average droplet size is below the maximum particle size understood the liquid in the dispersion.

The average maximum particle size is preferably about 0.1 to about 15 μm, in particular about 0.5 to about 12 µm or up to about 13 µm, for example about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 µm.

If the polymer forming the shell or a component of the shell as a dispersion is present, the average particle size of the polymer particles in the Dispersion maximum about 50 microns, but preferably less.

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.

It may be advantageous if the spray drying Dispersion is subjected to a treatment prior to spray drying, which the Particle size reduced or, if appropriate, aggregates present in the dispersion of disaggregated two or more particles. A suitable pretreatment procedure is for example ultrasound treatment. For this the spray drying intended dispersion 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,  treated at about 15 to about 25 ° C, for example. More suitable Pretreatment processes are, for example, the treatment for spray drying intended dispersion in the Ultra Turrax in the colloid mill, in the homogenizer, in one Mixing turbine or in a static mixer.

The dispersion 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 filler material consists of a cellulose ether or a mixture If two or more cellulose ethers are used, the preferred amount is Embodiment of the present invention, the proportion of cellulose ether or Cellulose ethers in the dispersion used for spray drying about 0.5 to about 5, in particular about 1 to about 4% by weight. When used for spray drying Dispersion polyvinyl alcohol or a copolymer containing polyvinyl alcohol or a Contains mixture of two or more such polymers, the proportion of these Polymers on the entire dispersion used for spray drying about 5 to about 40, in particular about 10 to about 30 wt .-%.

The proportion of the later capsule content in the dispersion used for spray drying is about 0.5 to about 40% by weight, for example about 1 to about 30% by weight. The Lower limit of the proportion of the later capsule content in that for spray drying dispersion used can be, for example, 1.5, 2, 3, 4, 5, 6, 7, 8, 9 or 10% by weight be. The upper limit for the proportion of the later capsule content in the Spray drying used dispersion is, for example, about 25 wt .-%, in particular, however, less than about 20% by weight, for example less than about 15% 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.

Chemicals are also suitable for producing the microcapsules according to the invention Microencapsulation. Here is a wall formation from monomeric or oligomeric starting materials preferred by polycondensation or polyaddition.  

A known encapsulation process is based on the principle of the interface Polycondensation. For example, a monomer component is dissolved in a solvent and disperses this solution in another, not with the first solvent miscible solvent. Then one with the first monomer component under Polymer formation reacting second monomer component of the continuous phase added so that at the interface of the dispersed solvent droplets Polymer film forms. The microcapsules obtainable in this way have a size which is approximately that of Size of the solvent droplets in the dispersion corresponds.

As an alternative to this method, for example, solids to be encapsulated with a functional group X in a form ground to a desired particle size a continuous phase can be finely dispersed, after which the a continuous phase a compound is added, which with the on the surface of the functional groups X to be encapsulated solids to form a Polymer film react. Systems suitable for such a method are for example the systems amine / isocyanate or amine / acid chloride where the amine is the is to be encapsulated. In this case, the continuous phase no reactive functional groups X on or those 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, together with a photosensitizer, is to form the capsule content, then these compounds are placed in an appropriate solvent and dispersed. A deactivation sheath or a polymer sheath can then be produced around the capsule content with the aid of a compound which is reactive towards the substances mentioned as capsule contents.

In a preferred embodiment of the present invention Generation of a capsule shell a monofunctional isocyanate as a deactivating agent  used, in particular an aromatic monofunctional isocyanate, for example Phenyl isocyanate.

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. In particular if a liquid amine is used as the capsule content, this leads Procedure using di- or higher functional isocyanates or acid chlorides to microcapsules, the size of which is essentially determined by the droplet size in the Dispersion present drops of liquid amine is determined.

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 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. Such small wall thicknesses can be achieved, for example, through chemical Achieve microencapsulation processes with deactivators. If as a capsule shell If a polymer is used, the wall thickness of the capsule is, for example at least about 50 or at least about 100 nm, for example about 120 to about 300 nm.

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 "curing" refers to in the context of the present invention  a chemical curing reaction that involves increasing molecular weight or crosslinking or both.

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 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 Contains groups X, and

the functional groups Y with the functional groups X under formation a covalent bond can react.

Component A of the adhesive according to the invention can be used within the scope 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 however, 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 a further embodiment of the invention, component B contains the Adhesive according to the invention at least one compound with at least two functional groups Y and at least one compound with at least two functional groups X.

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 from 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 the implementation of appropriate prepolymers, for example Prepolymers containing OH groups or NH groups are 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 epoxides 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 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 trimethylolpropane 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 (if necessary 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 of them are suitable. If necessary, minor amounts of monofunctional fatty acids are 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 the polyol component. 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., 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 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, for example, 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 For example, adhesive 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 or the ratio of functional groups X to functional groups Y in Component B or, if components A and B have at least one compound have functional groups X, the ratio of functional groups X in Component A and B to functional groups Y in component B about 1: 100 to about 1: 1. The term "equivalent ratio" is used in the context of the present Invention the ratio of functional groups X to functional groups Y Roger that.  

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 or at least one compound with at least two functional Groups Y and at least one compound with at least two functional Contains groups X and where the functional groups Y with the functional Groups X can react 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, in Depending on the chosen adhesive system, glue different substrates.

However, it has been found that in certain cases it is used to glue two Substrates is already sufficient if a microcapsule is present in an adhesive contains a compound as capsule content or as part of the capsule shell, which at Irradiation with high energy radiation opening the microcapsule and releasing it of the content contained in the microcapsule. In this case, however longer curing times may have to be accepted.

The present invention therefore also relates to a method for bonding at least two substrates in which at least one substrate is on the surface Adhesive, at least containing a microcapsule, consisting of a capsule shell and a capsule content, the capsule content at least one compound with at least 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 or a catalyst that causes a reaction between  towards isocyanate groups or epoxy groups or carboxyl groups or activated Functional groups X reactive to carboxyl groups and isocyanate groups or Catalyzes epoxy groups or carboxyl groups or activated carboxyl groups, has been applied to at least one substrate surface, and the adhesive before, during or after joining the substrates with high-energy radiation is irradiated, in the case of irradiation after joining the substrates at least one of the substrates for the high-energy radiation at least partially must be permeable.

Suitable microcapsules have already been described in the context of the present text, being a photosensitizer for carrying out the method according to the invention Part of the microcapsule is not mandatory.

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 irradiation of the microcapsule-containing one Adhesive with high-energy radiation. As high-energy radiation in the context of present invention a radiation with a wavelength of 200 to 700 nm, designated in particular from 220 to 650 nm.

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 radiation provided in the context of the method according to the invention with High-energy radiation can basically be before, during or after the joining  of the substrates. If the irradiation before joining the substrates takes place, the adhesive used should be set such that after opening the microcapsules still have a sufficient open time for the adhesive so that the substrates are joined together and, if necessary, subsequently corrected can. A suitable open time can, depending on the type of substrates bonded and the corresponding processing methods associated therewith, from about 1 s to about 1 h be.

If the adhesive is irradiated during the assembly of the substrates, it is said this is that between irradiation of the adhesive and the actual Joining the substrates is a time period that is less than about 1 s. A Corresponding energy source can be, for example, in this method variant be arranged that adhesive and substrate both before and after Be put together with an appropriate radiation dose. For the However, 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 method variant, in which the irradiation with high-energy radiation takes place only after the substrates have been joined together. Here it is necessary that at least the substrate facing the radiation source for the high-energy radiation used is permeable.

In a preferred embodiment of the present invention, the performed method with an adhesive, the inventive Contains microcapsules, that is, microcapsules containing a photosensitizer.

Within the scope of a further embodiment of the present invention Implementation of the method according to the invention, however, also uses an adhesive that use a photosensitizer as part of a component A contained microcapsules as component B surrounding matrix.  

The present invention therefore also relates to an adhesive which has at least two components A and B, wherein

• - As component A at least one microcapsule, consisting of a capsule shell and a capsule content, the capsule content comprising at least one 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 or a catalyst which is a reaction between isocyanate groups or Epoxy groups or carboxyl groups or activated carboxyl groups reactive functional groups X and isocyanate groups or epoxy groups or Catalyzed carboxyl groups or activated carboxyl groups and
• 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 is present as component B,
  wherein the functional groups Y can react with the functional groups X to form a covalent bond.

The same applies to the mixing ratios of the components in such an adhesive already above with regard to the adhesives, the microcapsules containing photosensitizer have information provided.

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, consisting of a capsule shell and a capsule content, the Capsule content 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 Carboxyl groups or a catalyst that opposes a reaction between Isocyanate groups or epoxy groups or carboxyl groups or activated Functional groups X reactive to carboxyl groups and isocyanate groups or Catalyzes epoxy groups or carboxyl groups or activated carboxyl groups, has, for radiation-induced bonding of substrates.

The invention is explained in more detail below by examples.

Examples

The UN 95 microcapsules used in the present examples were manufactured by Chemical microencapsulation process described above, wherein a Mixture of diamine and photosensitizer (benzophenone) with an aromatic Diisocyanate were wrapped. For the preparation of the mixture of diamine and The photosensitizer was melted on the diamine, with the photosensitizer in the Weight ratio of 1.3: 0.1 mixed and the mixture after solidification Grind particles with an average particle size of approximately 10 µm. The particles were then deactivated with an aliphatic diisocyanate and encapsulated. The capsule wall thickness was about 10 nm.

To check the effectiveness of the methods and systems according to the invention submitted the isocyanate component mentioned below and then a corresponding Amount of amine or encapsulated amine or encapsulated amine with photosensitizer added (5 g batches). The components were stirred in an aluminum bowl.

In a first test series, a PE film (type K088) and PMMA test specimens were used (25 × 10 × 3 mm) laminated with the adhesives specified in the table below  and irradiated with a UV device from Fusion (DRSE 120S) 3 cm out of focus. The Results are set out in Table 1 below.

Table 1

k. A. = no curing
Desmodur N3300 = EG 200; aliphatic polyisocyanate
ADPA = EG 92; 4-aminodiphenylamine
UN95 = microencapsulated ADPA, beige free-flowing powder, size: ≦ 100 µm)

In a further series of experiments, the above-mentioned PMMA test specimen with the above-mentioned Adhesive laminated and put together either before or after radiation. If assembly after irradiation was possible, the test specimens were left for 24 h stored and then measured the tensile shear strength of the bond. The Results are shown in Table 2 below.  

Table 2

k. A. = no curing
Desmodur N3300 = EG 200; aliphatic polyisocyanate
ADPA = EG 92; 4-aminodiphenylamine
UN95 = microencapsulated ADPA, beige free-flowing powder, size: ≦ 100 µm)

Claims (15)

1. Photosensitive microcapsule, consisting of a capsule shell and a Capsule content, the capsule content having at least one compound with at least two versus isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl reactive functional groups X or a Connection with at least two isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups or a catalyst which a reaction between against isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups reactive functional Groups X and isocyanate groups or epoxy groups or carboxyl groups or catalyzed activated carboxyl groups, and the capsule shell or Contains capsule content or both contains a photosensitizer. 2. Microcapsule according to claim 1, characterized in that the capsule shell Has wall thickness of at least 10 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 an OH group stand. 4. Microcapsule according to one of claims 1 to 3, characterized in that the Contains capsule content 0.01 to 10 wt .-% photosensitizer. 5. Microcapsule according to one of claims 1 to 4, characterized in that the Capsule content contains an at least difunctional amine. 6. adhesive, at least containing 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 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. 7. Adhesive according to claim 6, 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. 8. Adhesive according to claim 6 or 7, characterized in that the Equivalent ratio of reactive functional groups X in component A. functional groups Y in component B or the ratio of functional Groups X to functional groups Y in component B or, if Components A and B have at least one compound with functional groups X have the ratio of functional groups X in components A and B. to functional groups Y in component B is about 1: 100 to about 1: 1. 9. A method for producing an adhesive according to any one of claims 6 to 8, 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 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 .
be mixed. 10. Method for bonding at least two substrates, in which on 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 content at least one compound with at least two opposite Isocyanate groups or epoxy groups or carboxyl groups or activated Functional groups X reactive with carboxyl groups or a compound with at least two isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups or a catalyst that causes a reaction between versus isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl-reactive functional groups X and Isocyanate groups or epoxy groups or carboxyl groups or activated Catalyzed carboxyl groups, on at least one substrate surface is applied and the adhesive before, during or after a Joining the substrates is irradiated with high-energy radiation, wherein in the case of irradiation, at least one after the substrates have been joined together of the substrates be at least partially transparent to the high-energy radiation got to. 11. The method according to claim 10, characterized in that high-energy radiation with a wavelength of 200 to 700 nm is used. 12. The method according to claim 10 or 11, characterized in that the high-energy radiation has an energy density of at least about 0.5 W / cm ² . 13. Adhesive containing at least two components A and B, wherein
as component A at least one microcapsule, consisting of a capsule shell and a capsule content, the capsule content at least one compound having at least two functional groups X reactive towards isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups or a compound having at least two isocyanate groups or epoxy groups or carboxyl groups or activated Carboxyl groups or a catalyst which catalyzes a reaction between functional groups X which are reactive towards isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups and isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups 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. 14. Use of a microcapsule according to one of claims 1 to 5 for the production of adhesives. 15. Use of a microcapsule consisting of a capsule shell and a Capsule content, the capsule content having at least one compound with at least two versus isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl reactive functional groups X or a Connection with at least two isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups or a catalyst which a reaction between against isocyanate groups or epoxy groups or Carboxyl groups or activated carboxyl groups reactive functional Groups X and isocyanate groups or epoxy groups or carboxyl groups or activated carboxyl groups catalyzed, for radiation-induced Bonding of substrates.