MXPA99007715A

MXPA99007715A - Adhesive systems for a one or multi step adhesive binding method, method for adhesive binding of printed matter

Info

Publication number: MXPA99007715A
Application number: MXPA/A/1999/007715A
Authority: MX
Inventors: Onusseit Hermann
Original assignee: Henkel Kgaa 40589 Duesseldorf De
Priority date: 1997-03-07
Filing date: 1999-08-20
Publication date: 2000-02-02

Abstract

The invention relates to a photosensitive adhesive to increase the strength of adhesive binding for books. The inventive adhesive reacts radically and/or cationically and can be used in a one or two-shot process. Common hot-melt adhesives and dispersion adhesives can be used as a second adhesive. The novel method simplifies manipulation since pot life is unlimited.

Description

ADHESIVE SYSTEMS FOR BINDING METHOD WITH ADHESIVES OF A STEP OR SEVERAL STEPS, METHOD FOR BINDING WITH PRINTED MATERIAL ADHESIVES This invention refers to a system of adhesives based on at least one adhesive for a perfect one-step or multi-step binding process and a process for Perfect binding, brochures, books, catalogs, notebooks and similar printed articles by using this process. A perfect binding has been used successfully for a long time for the fast and economical production of books, catalogs, notebooks and brochures. In perfect binding processes, the function of the adhesive is, on the one hand, to hold the individual pages together along an edge, and on the other hand to attach a paste or a lining around the inner book. Optimal bonding of the individual pages is achieved if the edges of the individual pages can be fully humidified with the adhesive, and for this purpose low viscosity adhesives (eg hot melt adhesives or dispersion adhesives) are generally preferred. . However, the adhesion of the pastes generally requires higher viscosity products because the pastes consist partly of papers with very high weights per unit area that are very bulky and can only be adhered safely if the adhesive has a certain initial degree of stickiness. If only one adhesive can be used (one-step process), the viscosity should be selected in such a way as to ensure adequate adhesion of page edges and secure adhesion of the liner. Since these two requirements can not always be satisfied through a single adhesive, the idea of introducing what is known as a two-step process was adopted in the beginning. In the two-step process, two different adhesives are used, one after the other. In a first step, the inner book is very thinly coated with a dispersion or hot melt adhesive, preferably in a layer thickness of less than 0.2 mm. When a dispersion is used, the adhesive can be dried in a matter of seconds in the machine, for example, by using an infrared light dryer. The second adhesive is then applied in a second step. Depending on the nature of the system, the second adhesive is a dispersion adhesive at room temperature or a hot melt adhesive at temperatures between 120 and 200 ° C. In the two-step process, the low viscosity adhesive is responsible for the adhesion of the pages in step 1 while the high viscosity hot melt adhesive or dispersion adhesive is responsible for the strength of the inner book in step 2. An example of a 2-step process is described in WO85 / 04669. In this process, a water-based coupling agent is used as the first adhesive while a hot-melt adhesive is used as the second adhesive, the hot-melt adhesive contains a monoalkylene / vinyl acetate segmented copolymer and the agent Water-based coupling contains an aqueous emulsion of rubber latex. Accordingly, in this process, a non-reactive low viscosity adhesive is initially applied in the form of a dispersion while the hot melt adhesive is applied after drying of this step, in accordance with what is described above. Reactive systems are used both in one-step processes, for example in the form of reactive polyurethane hot-melt adhesives, and in two-step processes, for example, in the form of a reactive two-component dispersion and a fusion adhesive in hot. EP-A 0 568 803 relates to a book binding process wherein a water-based coupling agent and a hot melt adhesive are successively applied to the spine of an internal book, the coupling adhesive is an aqueous dispersion of an adhesive polymer resin and an isocyanate hardener. In this two-stage process, therefore, a reactive dispersion of two components is first applied, then the hot-melt adhesive is applied after the dispersion is dried. The disadvantage of the process presented in EP-A 0 568 803 is that the polymer to be crosslinked must always react with another substance in one of the two reaction steps. Therefore, systems of the type in question require either special application systems to avoid premature crosslinking before application (when the second component is water, for example air humidity) or have only a limited life of the can (in the case of two-component systems where chemical components are mixed). The problem to which the present invention is directed was to provide an improved adhesive system for a perfect one-step or multistep binding process for books, which would be particularly easier to handle. An adhesive system of the type in question is obtained through the presence of at least one photoinitiator in such a way that a low molecular weight component can be hardened through a radical or cationic reaction induced by electromagnetic radiation, for example radiation of UV light or more powerful electromagnetic radiation. In addition, known reactive groups, for example NCO groups, can also be present bound to either the same molecules that are capable of radiation-induced reaction or to different molecules. Accordingly, the present invention relates to an adhesive system for a perfect one-step or multi-step binding process for book binding, characterized in that it contains at least one photoinitiator and at least one adhesive A which is capable of induced reaction by radiation. Adhesive systems differ in their composition according to whether they are used in a one-step process or in a two-step process. In the one-step process, the adhesive system comprises as adhesive A a radiation-crosslinkable adhesive of a low viscosity crosslinkable mixture of monomers and / or polymers having a viscosity of 0.1 to 20 and preferably 0.1 to 10 Pas a the application temperature and which also contains at least one photoinitiator. In the two-step process, the adhesive system according to the present invention comprises the adhesive A, that is, a low viscosity radiation-curable adhesive (for example, systems without solvent or systems with solvent or dispersion) having a viscosity at the application temperature of 100 to 10000 mPas and preferably within the range of 100 to mPas and also containing at least one photoinitiator and the adhesive B having a viscosity at the application temperature of 1,000 to 20,000 mPas and preferably a viscosity at the application temperature within the range of 5000 to 10000 mPas. Apart from the virtually unlimited life of the boat, the advantage of this system is that there is no need to maintain any mixing ratio and no special applicators are required. This provides simple production on an industrial scale. In the context of the present invention, a "perfect multi-step binding process" is understood as a perfect binding process comprising at least two application steps, with the two-step process being preferred. understands as a radical or cationic reaction where molecular weight increases. Accordingly, an adhesive A is based on blends without solvent or mixtures containing solvents in the form of aqueous solutions or dispersions of, preferably, acrylate monomers and / or polymers modified by acrylate and / or aliphatic epoxy monomers and / or polymers modified by epoxy. In cases in which the molecular weight is increased by a radical reaction, the functional group is in general an olefinically unsaturated double bond. In accordance with the present invention, olefinically unsaturated double bonds present, for example, in acrylic acid or styrene derivatives are preferred. Derivatives of acrylic acid, for example acrylates or methacrylates containing 1 to 16 and preferably 1 to 4 carbon atoms in the alcohol component are particularly suitable and preferred for the purposes of the invention. An adhesive A according to the present invention preferably contains at least one polymer with a molecular weight of at least 800 as the component is radically reactive. Suitable reactive components are any of the polymeric compounds typically used in adhesives, for example, polyvinyl acetate, polyvinylidene chloride, polyacrylates, polyesters, polyethers, polycarbonates, polyacetals, polyurethanes, polyolefins or rubber polymers, such as, for example, nitrile, chloroprene , isoprene or styrene / butadiene rubber, provided that they contain at least one polymerizable functional group by exposure to UV light or to electron beams and optionally at least one functional group capable of reacting with a compound containing at least one carbon atom. acid hydrogen, for example, an NCO group. However, polyacrylates, polyesters or polyurethanes are preferably used as the reactive component in the adhesives according to the present invention, because the mentioned polymers make it particularly easy to fix the functional groups required according to the present invention on the polymer molecule. Polymers suitable for use as a reactive component according to the present invention can be particularly easily from a basic polymer containing at least two functional groups which react with isocyanate, preferably OH groups, in the polymer molecule. The required functional group can be fixed particularly easily on this basic polymer by reaction with a polyisocyanate or a suitably functionalized monoisocyanate. An example of a suitable basic polymer is a polymer selected from the group consisting of polyesters, polyethers, polycarbonates or polyacetals with a molecular weight (Mn) of at least about 200 or mixtures of two or more polymers of this type containing groups OH terminals. Polyesters suitable for use in accordance with the present invention as the basic polymer for the production of the reactive component can be obtained in a known manner by polycondensation of acid and alcohol components, more particularly by polycondensation of a polycarboxylic acid or a mixture of two or more polycarboxylic acids and a polyol or a mixture of two or more polyols. Suitable polycarboxylic acids according to the present invention for the production of the basic polymer can be based on a compound of an aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic gene and, in addition, the at least two carboxylic acid groups can optionally contain one or several substituents which do not react in the course of a polycondensation reaction, for example halogen atom or olefinically unsaturated double bonds. The free carboxylic acids can even be replaced by their anhydrides (when they exist) or esters with C1-C5 monoalcohols or mixtures of two or more of them for the polycondensation reaction. Suitable polycarboxylic acids are, for example, succinic acid, adipic acid, suberic acid, azelaic acid, sebasic acid, glutaric acid, glutaric anhydride, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimeric fatty acids, or trimeric fatty acids, or mixtures of two or more thereof. Small amounts of monofunctional fatty acids may optionally be present in the reaction mixture.

Various polyols such as diols can be used for the production of a polyester or polycarbonate for use as the basic polymer, examples of such polyols are aliphatic polyols, which contain from 2 to 4 OH groups per molecule. The OH groups may be primary or secondary OH groups. Suitable aliphatic polyols include, for example, ethylene glycol, propan-1,2-diol, propan-l, 3-diol, butan-1,4-diol, butan-1,3-diol, butan-2,3-diol, buten-1, 4-diol, butin-1,4-diol, pentan-1,5-diol, and the pentanediols, pentendiols, or isomeric pentindiols or mixtures of two or more of them, hexan-1,6-diol and hexandiols, hexendiols or isomeric hexindiols or mixtures of two or more of them, heptan-1, 7-diol and the isomeric heptandiols, heptadiols or heptindiols, octan-1, 8-diol and the isomeric or homologous o-n-octanediols or ocdi-diols; higher isomers of the aforementioned compounds which are obtained in a known manner in a stepwise extension of the carbon chain by a CH2 group at the same time either by introducing branches in the carbon chain, or by mixtures of two or more from them. Other suitable polyols are alcohols of relatively high functionality, for example glycerol, trimethylolpropane, pentaerythritol or sugar alcohols such as, for example, sorbitol or glucose, and oligomeric ethers of the substances mentioned, either as such or as a mixture of 2 or more than the compounds mentioned therebetween, for example polyglycerol with a degree of polymerization of from about 2 to about 4. In alcohols of relatively high functionality, one or more OH groups can be esterified with monobasic carboxylic acids containing from 1 to about 20 carbon atoms, provided that, on average, at least two OH groups remain intact. The aforementioned higher alcohols can be used in pure form, or, as possible, in the form of technical mixtures obtainable in the course of their synthesis. The products of the reaction of polyfunctional alcohols of low molecular weights with alkylene oxides, which are known as polyester polyols, can also be used as the polyol components for the production of basic polymers. Polyester polyols which are used for the production of polyesters suitable as the basic polymers are preferably obtained by reaction of polyols with alkylene oxides. The alkylene oxides preferably contain from 2 to about 4 carbon atoms. Suitable polyether polyols are, for example, the reaction products of ethylene glycol, propylene glycol, isomeric butanediols or hexanediols, as mentioned above, or mixtures of 2 or more of them with ethylene oxide, propylene oxide or butylene oxide or mixtures of two or more of them. Other suitable polyether polyols are products of the reaction of polyfunctional alcohols such as for example glycerol, trimethylolethane or trimethylolpropane, pentaerythritol or sugar alcohols or mixtures of two or more of them, with the aforementioned alkylene oxide to form polyether polyols. Polyether polyols with a molecular weight (Mn) of about 100 to 3000 and preferably within the range of about 200 to about 2000 which can be obtained from the reactions mentioned are particularly suitable. The polyether polyols mentioned can react with the polycarboxylic acids mentioned above in a polycondensation reaction to form the polyethers suitable for use as the basic polymers. Polyether polyols formed, for example, in accordance with that described above are also suitable as basic polymers terminated in OH. Polyether polyols are usually obtained by the reaction of an initial compound containing at least two hydrogen atoms reactive with alkylene or arylene 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, 1,2- or 1,3-propylene glycol, 1,4- or 1,3-butylene glycol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1, 4-hydroxymethylcyclohexane, 2-methylpropan-1,3-diol, glycerol, trimethylolpropane, hexan-1,2,6-triol, butan-1,2,4-triol, trimethylolethane, pentaerythritol, mannitol, sorbitol, sugars methylglycosides, phenol, isononylphenol, resorcinol, hydroquinone, 1,2,2- or 1,1,2-tris- (hydroxyphenyl) -ethane, ammonium, methylamine, ethylenediamine, tetra- or hexamethylenediamine, triethanolamine, aniline, phenylenediamine, 2,4- and 2, 6-diaminotoluene and polyphenylpolymethylenepolyamines obtainable by the condensation of aniline with formaldehyde. Polyether polyols modified by vinyl polymers are also suitable for use as the basic polymer. Products of this type can be obtained, for example, by the polymerization of styrene or acrylonitrile or a mixture thereof in the presence of polyethers. A particularly suitable polyether polyol according to the present invention for use as a basic polymer is polypropylene glycol with a molecular weight of about 300 to about 1,500. Polyacetals are also suitable for use as the basic polymer or as the polyol component for producing the basic polymer. Polyacetals are understood as compounds that can be obtained by the reaction of glycols, such as, for example, diethylene glycol, or hexanediol, with formaldehyde. Polyacetals suitable for the purposes of the present invention can also be obtained by the polymerization of cyclic acetals. The polycarbonates are also suitable for use as the basic polymer or as the polyol used for the production of the basic polymer. The polycarbonates can be obtained, for example, by the reaction of the polyols mentioned above, more particularly, diols, such as propylene glycol, butan-1,4-diol or hexan-1,6-diol, diethylene glycol, triethylene glycol, or tetraethylene glycol or mixtures of two or more of them, with diaryl carbonates, such as, for example, diphenylcarbonate or phosgene. Polyacrylates with OH functionality are also suitable as the basic polymer or as the polyol component used for the production of the basic polymer. Polyacrylates with OH functionality can be obtained, for example, by the polymerization of ethylenically unsaturated monomers bearing OH groups. Such monomers can be obtained, for example, by the esterification of ethylenically unsaturated carboxylic acids and difunctional alcohols, alcohol is generally present only in a slight excess. Ethylenically unsaturated carboxylic acids suitable for this purpose are, for example, acrylic acid, methacrylic acid, crotonic acid or maleic acid. Esters with corresponding OH functionality are, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, or 3-hydroxypropyl methacrylate or mixtures thereof. of two or more of them. If the molecular weight of the basic polymer is too low for its use as a reactive component, it can be increased, for example, by chain extension. For this purpose, the OH-terminated basic polymer reacts initially with a polyfunctional compound, preferably a bifunctional compound (functionality related to terminal OH groups). Accordingly, in the context of the present invention, particularly suitable polyfunctional compounds are polyepoxides, more especially diepoxy, or preferably polyisocyanates, more especially diisocyanates. Diisocyanates are particularly preferred for the purposes of the invention. The stoichiometric relationships between the basic polymer and the polyfunctional compound required to obtain a certain increase in molecular weight known to those skilled in the art. In general, however, the excess of basic polymer will be present within the chain extension reaction in order to obtain an increase in the length of the chain, the basic extended chain polymers formed are again terminated by OH groups. In order to be suitable for use as a reactive component, the basic polymers of optionally extended chain, terminated with OH mentioned above must be equipped with at least one polymerizable functional group by exposure to UV light or electron beams and optionally with at least one polymerizable functional group by reaction with a compound containing at least one acid hydrogen atom. For this purpose, the basic polymers react preferably with a compound that is polyfunctional and preferably difunctional in relation to the terminal OH groups. Suitable polyfunctional compounds for the purposes of the present invention are the polyfunctional compounds already usable for chain extension, more especially polyepoxides, particularly diepoxides, but preferably polyisocyanates, especially diisocyanates.

Diisocyanates are particularly preferred for the purposes of the present invention. Suitable polyfunctional polyisocyanates which are suitable for reacting with the basic polymers contain on average two to a maximum of about four isocyanate groups. Examples of suitable isocyanates are 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), hydrogenated MDI (dicyclohexylmethane diisocyanate, Hi2-MDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), 4,4 '-difenyldimethylmethane diisocyanate and di- and tetraalkyldiphenylmethane diisocyanate, 4,4'-di-benzene diisocyanate, diisocyanate of 1,3-phenylene, 1,4-phenylene diisocyanate, 2,4- and 2,6-toluene diisocyanate (TDI) and mixtures thereof, more particularly a mixture containing 2,4-toluene diisocyanate in about 20 % by weight and 80% by weight of 2,6-toluene, 1-methyl-2,4-diisocyanatocyclohexane, 1, β-diisocyanate-2,2,4-trimethylhexane, 1,6-diisocyanate-2, 4, 4 -trimethylhexane, 1-isocyanatoethyl-3-isocyanato-1,5,5-trimethylcyclohexane (IPDI), chlorinated and brominated diisocyanates, phosphorus-containing diisocyanates, 4,4'-diisocyanatophenylperfluoroethane, tetramethoxybutan-1,4-diisocyanate, 1,4 -butanediisocyanate, 1,6-hexanediisocyanate (HDI), cyclohexane-1,4-diisocyanate, ethylene diisocyanate, bis-isocyanatoethyl ether of phthalic acid, polyisocyanates containing reactive halogen atoms, such as for example l-chloromethylphenyl-2,4-diisocyanate, l-bromomethylphenyl-2,6-diisocyanate, 3, 3-bis-chloromethylether-4,4'-diisocyanate diphenyl. Sulfur-containing polyisocyanates obtainable, for example, by the reaction of two moles of hexamethylene diisocyanate with 1 mole of thiodiglycol or dihydroxydihexyl sulfide are also suitable. Other diisocyanates are trimethylhexamethylene, 1,4-diisocyanatobutane, 1,2-diisocyanatododecane diisocyanates and fatty dimeric acid diisocyanates. Triisocyanatoisocyanurates can be obtained by trimerization of diisocyanates at elevated temperature, for example, at a temperature of about 200 ° C, and / or in the presence of a catalyst, for example, an amine, and can also be used for the purposes of the present invention. invention. According to the invention, the polyisocyanates mentioned can be used either individually or in the form of a mixture of two or more of the polyisocyanates mentioned. A single polyisocyanate or a mixture of two or three polyisocyanates are preferably used for the purposes of the present invention. The preferred polyisocyanates employed either individually or in admixture are HDI, MDI or TDI, for example, in a mixture of MDI and TDI. The basic polymer reacts preferably with the polyfunctional compound, preferably with the diisocyanate, in a ratio of 1: > 2, the polyfunctional compound excess is, for example, just large enough to avoid the chain extension of the basic polymer, even though only small amounts of unreacted polyfunctional compound are present in the reaction component. A process of this type can be useful particularly when a diisocyanate is used as the polyfunctional compound. A polymer terminated by two functional groups that can be polymerized by reaction with a compound containing at least one hydrogen atom acid is obtained in this way. In order to obtain a polymer suitable for use as a reactive component from such a polymer, the polymer preferably reacts with a compound that contains both a polymerizable functional group by exposure to UV light or electron beams and a functional group suitable for reaction with the terminal functional group of the polymer. Hydroxyalkyl acrylates or methacrylates, that is, the products of the reaction of acrylic acid or methacrylic acid with difunctional alcohols are especially suitable for this purpose. Hydroxyacrylates or methacrylates particularly suitable for use in accordance with the present invention are, for example, 2-hydroxyethyl acrylates, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate or 3-hydroxypropyl methacrylate or mixtures of two or more thereof. Suitable polymers for use as a reactive component can also be obtained, for example, in several steps. In a first step, the OH-terminated basic polymer reacts with a compound that contains both a polymerizable functional group by exposure to UV light or electron beams and a functional group capable of reacting with the terminal OH group of the basic polymer. An example of a compound of this type is styrene isocyanate. Other compounds of this type can be obtained, for example, by reacting a substantially equimolar amount of a hydroxyalkyl acrylate or hydroxyalkyl methacrylate with a diisocyanate. After the reaction of a substantially equimolar amount of the basic polymer (optionally adapted by chain extension to the molecular weight required for use in component A) with such a component in a second step, a polymer terminated by both an OH group as a polymerizable functional group by exposure to UV light or electron beam is formed. If this polymer reacts as, for example, with a diisocyanate, a polymer suitable for use as the reactive component is obtained. The two steps mentioned above can also be combined by the reaction of a basic polymer, a diisocyanate (or optionally another polyfunctional compound in the context of the aforementioned observations) and a compound that contains both a polymerizable functional group by exposure to UV light or electron rays as a functional group capable of reacting with the terminal OH group of the basic polymer between them in a suitable molar ratio in such a way that the percentages of the two types of functional groups in the polymer mixture obtainable by said reaction vary between more than 0% and less than 100% (based on the functional groups). Favorable results may be obtained, for example, if from about 1 to about 50%, preferably from about 5 to about 30%, and more preferably from about 8 to about 15% of the functional groups present as end groups in the polymer they are polymerizable functional groups by exposure to UV light or electronic rays. The typical NCO contents for the polymers employable for use as a reactive component are from about 2.5 wt% to about 7 wt%, and more particularly from about 3.5 wt% to about 5%. The reactive component used according to the present invention may consist of only one of the polymers described, although it may be advantageous to represent a mixture of two or more of the polymers mentioned. For example, it is advantageous to employ a mixture of one or more polyester polyols and one or more polyether polyols as the basic polymer. The various basic polymers may differ, for example, in terms of their molecular weights (Mn) either in terms of their chemical compositions or in both. In a preferred embodiment of the invention, from about 20 to about 40% by weight of polyester polyols and from about 20 to about 60% by weight of polyether polyols, based on component A globally, are used as the basic polymers for the production of the reactive component. In another preferred embodiment, at least two different polyether polyols, more particularly a mixture of a polyether polyol with a molecular weight of about 800 to about 1500 and a polyether polyol with a molecular weight of about 300 to about 700 are employed in addition to a polyol. of polyester as the basic polymer. To produce the reactive component, the individual basic polymers can be provided with functional groups and optionally extended chain, in accordance with what has been described above, in such a way that they are directly suitable for use as the component of the reaction. In a preferred embodiment of the invention, however, a mixture of basic polymers with OH functionality reacts initially with a suitable amount of polyisocyanates and then - in a suitable molar ratio - with compounds containing both a polymerizable functional group by exposure to light UV or electron beam as a functional group capable of reacting with the terminal OH group of the basic polymer. In another embodiment, at least one compound with a molecular weight of about 100 to about 8,000 which contains at least two polymerizable functional groups with exposure to UV light or electron beams can also be employed as a reactive component. Accordingly, acrylates or methacrylates with a functionality of two or more are especially suitable as a reactive component. Acrylates or methacrylates of this type include, for example, esters of acrylic acid or of methacrylic acid with aromatic, aliphatic or cycloaliphatic polyols or acrylate esters of polyether alcohols. Various polyols can be used as polyols for the production of suitable reactive acrylate or methacrylate esters of the type in question. Examples of such polyols are aliphatic polyols containing from 2 to 4 OH groups per molecule and from 2 to about 40 carbon atoms. The OH groups can be both primary and secondary OH groups. Suitable aliphatic polyols include, for example, ethylene glycol, propan-1,2-diol, propan-1,3-diol, butan-1,4-diol, butan-1,3-diol, butan-2,3-diol, buten-1,4-diol, butin-1,4-diol, pentan-l, 5-diol and the pentanediols, pentendiols or isomeric pentindiols or mixtures of two or more of these, hexane-1,6-diol and the hexanediols , isomeric hexenediols or hexindiols or mixtures of two or more of them, heptan-1, 7-diol, and the isomeric heptandiols, heptadiols or heptindiols, octan-1, 8-diol and the isomeric octaindiols or ocdi tols and homologs or isomers The above-mentioned compounds, which can be obtained in a known manner by stepwise extension of the hydrocarbon chain by a CH2 group at the same time or by introducing branches in the carbon chain, or by mixtures of two or more, can be obtained in a known manner. from them. Other suitable polyols are higher alcohols, such as for example glycerol, trimethylolpropane, pentaerythritol, or sugar alcohols, for example sorbitol or glucose, and oligomeric ethers of the aforementioned substances, either as such or in the form of mixtures of two or more of the compounds mentioned among them, for example polyglycerol with a degree of polymerization of about 2 to about 4. In the case of higher alcohols, one or more OH groups can be esterified with monobasic carboxylic acids containing from 1 to about 20 carbon atoms. carbon, provided that, on average, at least two OH groups remain intact. The mentioned higher alcohols can be used in pure form or, if possible, in the form of the technical mixtures that can be obtained in the course of their synthesis. In addition, products of the reaction of low molecular weight polyfunctional alcohols with alkylene oxides, which are known as polyether polyols, can be used as the polyol component for the production of the acrylate or methacrylate esters. The polyether polyols intended for use for the production of polyesters suitable as basic polymers are preferably obtained by reaction of polyols with alkylene oxides. The alkylene oxides preferably contain from 2 to about 4 carbon atoms. Suitable polyether polyols are, for example, the products of the ethylene glycol reaction, propylene glycol, isomeric butanediols or hexandiols, as mentioned above, or mixtures of two or more of them with ethylene oxide, propylene oxide, or butylene oxide or mixtures of two or more of them. Products of the reaction of polyfunctional alcohols such as glycerol, trimethylolethane or trimethylolpropane, pentaerythritol or sugar alcohols, or mixtures of two or more of them with the abovementioned alkylene oxides to form polyether polyols are also suitable. Polyether polyols with a molecular weight (Mn) of about 100 to about 2000, preferably in the range of about 150 to about 1500 and more preferably within the range of about 150 to about 800 that can be obtained from the reactions mentioned are particularly suitable.

Acrylate esters of aliphatic diols containing from 2 to about 40 carbon atoms include, for example, neopentyl glycol di (meth) acrylate, 1,6-hexandiol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetra (meth) pentaerythritol acrylate and sorbitol (meth) acrylate esters and other sugar alcohols. These (meth) acrylate esters of aliphatic or cycloaliphatic diols can be modified with an aliphatic ester or an alkylene oxide. Acrylates modified by an aliphatic ester comprises, for example, neopentyl glycol hydroxypivalate di (meth) acrylate, di (meth) acrylates of neopentyl glycol hydroxypivalate modified with caprolactone and the like. Acrylate compounds modified with alkylene oxides include, for example, di (meth) acrylates of neopentyl glycol modified with ethylene oxide, di (meth) acrylates of neopentyl glycol modified with propylene oxide, di (meth) acrylates of 1,6- hexandiol modified with ethylene oxide or di (meth) acrylates of hexan-1,6-diol modified with propylene oxide or mixtures of two or more of them. Acrylate monomers based on polyether polyols comprise, for example, di (meth) acrylates of trimethylolpropane modified with neopentyl glycol, di (meth) acrylates of polyethylene glycol, di (meth) acrylates of polypropylene glycol and the like. Trifunctional and higher acrylate monomers comprise, for example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate , dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth), pentaerythritol tetra (meth) acrylate, tris [(meth) acryloxyethyl] -isocyanurate, tris [(meth) acryloxyethyl] -isocyanurates modified with caprolactone or tetra (meth) -trimethylolpropane acrylate or mixtures of two or more of them. Of the aforementioned difunctional, trifunctional or higher acrylate monomers which can be used according to the present invention as the reactive component, tripropylene glycol diacrylate, neopentyl glycol propoxylate di (meth) acrylate, trimethylolpropane tri (meth) acrylate are preferred. and pentaerythritol triacrylate. The adhesives A according to the present invention contain the reaction component in an amount of about 10 to about 99.9% by weight and preferably in an amount of about 15 to about 99% by weight. The molar ratios between the basic polymer and the compound containing both a polymerizable functional group by exposure to UV light or to electron beams and a functional group capable of reacting with the terminal functional group of the polymer can vary within wide limits during the reaction. In general, a greater number of polymerizable functional groups by exposure to UV light or electron beams in the reactive component causes an adhesive bond of a relatively high strength while a more important number of functional groups capable of reacting with a compound containing the less an acid hydrogen atom leads to a greater ultimate strength. If, for example, the basic polymer reacts with the compound containing both a polymerizable functional group by exposure to UV light or electron beams and a functional group capable of reacting with the terminal functional group of the polymer in a molar ratio of about 1: 1, each polymer molecule in the resulting polymer mixture contains on average both a functional group polymerizable by exposure to UV light or electron beams and a functional group capable of reacting with a compound containing at least one acid hydrogen atom. The percentages of the two types of functional groups in the polymer mixture obtainable by said reaction may therefore vary between greater than 0 and greater than 100% (based on the functional groups in the context of the present invention). You can get good results like for example, if from about 100 to about 10%, preferably from about 1 to about 50%, and more preferably from about 8 to about 15% of the functional groups present as end groups in the polymer are polymerizable functional groups by exposure to the UV light or electronic rays. When the molecular weight is increased by cationic reaction, the compounds in question are styrenes, vinyl ethers and epoxides, either compounds of low molecular weights or correspondingly modified macromolecular compounds, more particularly compounds containing epoxy groups. An "epoxy group" in the context of the present invention is a functional group that contains an oxirane ring. Epoxy groups such as these can be polymerized in a known manner by cationically initiated polymerization. The adhesive employed in accordance with the present invention may contain an aliphatic compound containing at least one epoxy group as a single constituent, although a mixture of two or more compounds containing at least one epoxy group may also be employed. The epoxy compound can also be used together with radically reactive compounds containing the olefinically unsaturated double bonds described above, more especially with the acrylate monomers and / or polymers modified by acrylate, and in some cases even with the isocyanate compounds. To produce polymers, it is sufficient if the compound containing at least one epoxy group present as a constituent of the adhesive contains only one epoxy group. However, to obtain a greater degree of crosslinking in the adhesive film, it may be desirable to employ at least partially one or more compounds containing more than one epoxy group in the molecule as a constituent of the adhesive A. The compounds employed advantageously contain 1 to about 4 epoxy groups per molecule. In a particularly preferred embodiment, the average epoxy group content of the adhesive A is overall from about 1 to about 2.5 and, more particularly, from about 1.5 to about 2.0. In principle, a low molecular weight epoxide can be used as the compound containing at least one epoxide group, even when epoxides of relatively high molecular weights or mixtures of epoxides of low molecular weights and relatively high molecular weights can also be employed. In the context of the present invention, "low molecular weight compounds" are compounds that contain at least one epoxy group having a molecular weight no greater than about 400. Accordingly, compounds that contain at least one epoxy group with a molecular weight greater than 400 are known as "relatively high molecular weight compounds" in the present specification. Compounds with relatively high molecular weights containing at least one epoxy group may contain the epoxy group such as, for example, at the end of a polymer chain even though the epoxide group may also be located within the polymer chain or may be fixed laterally on the polymer chain. In the case of compounds containing more than one epoxy group, the corresponding relatively high molecular weight compound may also contain epoxy groups in two or more of the configurations described in relation to the polymer backbone. Thus, a compound containing more than one epoxide group, for example, may have a terminal epoxide group and a side epoxide group or an epoxide group within the polymer structure and a side epoxide group. Compounds containing at least one epoxy group suitable for use as adhesive A in accordance with the present invention include, for example, cycloaliphatic epoxies. Examples of cycloaliphatic epoxides are bis- (3, 4-epoxycyclohexylmethyl) -oxalate, bis- (3, 4-epoxycyclohexylmethyl) -adipate, bis- (3,4-epoxy-6-methylcyclohexylmethyl) -adipate and / or bis- (3,4-epoxycyclohexylmethyl) -pimelate. Also suitable are 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylates, for example, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylic acid, 3,4-epoxy-1-methylcyclohexylmethyl-3,4-epoxycarboxylic acid. l-methylcyclohexanecarboxylic acid, 6-methyl-3,4-epoxycylmethyl-6-methyl-1,3-, 4-epoxycyclohexanecarboxylic acid, 3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexanecarboxylic acid -epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylic acid and the like. Other suitable epoxides which can be used for the purposes of the present invention are glycidyl ethers which can be obtained, for example, from polyhydric phenols, for example diglycidyl ethers of 2,2'-bis- (2,3-epoxy-propoxyphenol) -propane. Commercially available compounds containing at least one epoxy group can also be used to advantage. Examples of such compounds are octadecylene oxide, epichlorohydrin, styrene oxide, vinylcyclohexene oxide, glycidol, glycidyl methacrylate, diglycidyl ethers of bisphenol A (for example EPON 818, EPON 1004 and EPON 1010, products of Shell Chemical Co.; DER-331, DER-332 and DER-334, products of Dow Chemical Co. ), vinylcyclohexene dioxide (e.g. ERL-4206, a product of Union Carbide Corp.), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexene carboxylate (e.g., ERL-4221, a product of Union Carbide Corp.), 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexene carboxylate (for example ERL-4201, a product of Union Carbide Corp.), bis- (3,4-epoxy-6-methylcyclohexylmethyl) -adipate (for example ERL-4289, a product of Union Carbide Corp.), bis- (2, 3-epoxy-cyclopentyl) -ether (for example ERL-0400, a product of Union Carbide Corp.), an epoxy resin modified with propylene glycol, aliphatic (for example ERL-4050 or ERL-4052, products of Union Carbide Corp.), dipentene dioxide (for example ERL-4269, a product of Union Carbide Corp.), epoxidized polybutadiene (for example OXIRON 2001, a product of FMC Corp.), epoxy-functional silicone resin, flame-retardant epoxy resins (eg DER-80, a product of Dow Chemical Co.), diglycidyl ether or butan-1,4-phenol / formaldehyde novolak diol (for example DEN-431 or DEN-438, products of Dow Chemical Co.) and resorcinol diglycidyl ether (for example, KOPOXITE, a product of Koppers Co. , Inc.). Other suitable compounds containing at least one epoxy group are epoxy-functional polymers obtainable, for example, by the polymerization of epoxy-functional epoxy-ethylenically unsaturated compounds. Examples of such epoxy-functional ethylenically unsaturated compounds are glycidol acrylates, for example diglycidyl acrylates and glycidyl methacrylate. These compounds are advantageously copolymerized with at least one other ethylenically unsaturated compound without an epoxy group. Polyurethanes containing epoxy groups, for example, are also suitable. Such polyurethanes can be obtained, for example, by the reaction of polyesters containing OH or polyethers containing OH with polyfunctional isocyanates, the stoichiometric ratio between isocyanate groups and OH groups is selected such that the corresponding polyurethane contains at least one free isocyanate group which subsequently reacts, for example, with l-hydroxy-2,3-epoxypropane or another suitable epoxide. Adhesive A generally contains up to 100% by weight and preferably up to 30% by weight of a compound containing only one epoxy group. The percentage of compounds containing two or more epoxy groups is up to about 100% by weight and preferably from about 10 to about 40% by weight, the percentage of trifunctional and higher epoxides in the adhesive A is up to about 10% in weigh. In addition to the aliphatic epoxy compound, the adhesive A contains a compound containing at least two OH groups with a molecular weight of less than 400. The percentage of trifunctional compound, ie, a compound containing three OH groups is from about 1 to about 10. % by weight, based on the global adhesive. If adhesive A also contains NCO groups, it is advisable either not to use polyols or to add them only immediately before use. Suitable OH-containing compounds are, for example, higher alcohols such as glycerol, trimethylolpropane, pentaerythritol and sugar alcohols, and oligomeric ethers of the aforementioned individual compounds or oligomeric ethers of a mixture of two or more of the compounds mentioned therebetween. The products of the reaction of low molecular weight polyfunctional alcohols with alkylene oxides containing up to 4 carbon atoms can also be used as a polyol component for the production of the polyesters. Suitable reaction products are, for example, the products of polyfunctional alcohols, such as for example glycerol, trimethylolethane and / or trimethylolpropane, pentaerythritol or sugar alcohols, with the aforementioned alkylene oxides to form oligoether polyols with a molecular weight not greater than about 400. The adhesive A according to the present invention can contain as a polyol a compound containing at least two OH groups with a molecular weight of at least 400 or a mixture of two or more such compounds. The compounds used as polyols preferably have a molecular weight of more than about 400 to about 10., 000 and, more preferably, within the range of more than about 400 to about 2,000. Suitable polyols are, for example, polyester polyols, polyether polyols, polyurethane polyols, polycarbonate polyols, polyvinylacetal polyols, polyacrylate polyols, polymethacrylate polyols, or suitable acrylate and methacrylate copolyols or mixtures of two or more the polyols mentioned. A particularly preferred embodiment of the invention is characterized by the use of polyester polyols, polyether polyols or polyurethane polyols. Preferred polyester polyols are produced by the reaction of low molecular weight alcohols, more particularly ethylene glycol, diethylene glycol, neopentyl glycol, hexanediol, butanediol, propylene glycol, glycerol or trimethylolpropane, by polycondensation with a polycarboxylic acid or a mixture of such acids. For example, difunctional and / or trifunctional alcohols can be condensed with dicarboxylic acids and / or tricarboxylic acids or reactive derivatives thereof to form the polyesters. Suitable dicarboxylic acids are, for example, succinic acid and higher homologs containing up to 16 carbon atoms, unsaturated carboxylic acids such as for example maleic acid or fumaric acid, and aromatic dicarboxylic acids, more especially isomeric italic acids, for example phthalic acid, isophthalic acid or terephthalic acid. Suitable tricarboxylic acids are, for example, citric acid or trimellitic acid. Also suitable are aliphatic polycarboxylic acids such as for example adipic acid, glutamic acid, pimelic acid, aromatic acids, such as naphthalenedicarboxylic acid, cycloalkyl acids, such as cyclohexanedicarboxylic acid or heteroatom containing acids such as for example S or N, for example diglycolic acid, 2,2-dicarboxylic acid ethyl ether or thiodiglycolic acid. Other polyols suitable for the production of the polyesters are aliphatic alcohols containing two to four OH groups per molecule. The OH groups are preferably primary OH groups even though they may also be secondary OH groups. Suitable aliphatic alcohols are, for example, ethylene glycol, propylene glycol, butan-1,4-diol, pentan-1,5-diol, hexane-1,6-diol, heptan-1,7-diol, octane-1, 8- diol and higher homologs and isomers thereof which can be obtained in a known manner by stepwise extension of the hydrocarbon chain by a CH2 group at the same time or by introduction of branches in the carbon chain. Other suitable polyols are higher alcohols, for example glycerol, trimethylolpropane, pentaerythritol and oligomeric ethers of the substances mentioned either as such or in the form of mixtures of two or more of the ethers mentioned therebetween. The products of the reaction of low molecular weight polyfunctional alcohols with alkylene oxides containing up to 4 carbon atoms can also be used as a polyol component for the production of the polyesters. Suitable reaction products are, for example, the reaction products of ethylene glycol, propylene glycol, the isomeric butanediols or hexanediols with ethylene oxide, propylene oxide and / or butylene oxide. Products of the reaction of polyfunctional alcohols, for example, glycerol, trimethylolethane and / or trimethylolpropane, pentaerythritol or sugar alcohols with the aforementioned alkylene oxides to form polyether polyols are also suitable. The products of the reaction of polyfunctional alcohols of low molecular weights with alkylene oxides containing up to 4 carbon atoms can also be used as polyol components for the production of the polyesters. Suitable reaction products are, for example, the reaction products of ethylene glycol, propylene glycol, butanediols or isomeric hexanediols with ethylene oxide., propylene oxide and / or butylene oxide. Reaction products of polyfunctional alcohols such as for example glycerol, trimethyloletanol and / or trimethylolpropane, pentaerythritol or sugar alcohols with the aforementioned alkylene oxides to form polyether polyols are also suitable. Polyols particularly suitable for the production of the polyesters are polyether polyols with a molecular weight of about 100 to 5,000 and preferably in the range of about 200 to about 3,000. More particularly propylene glycol with a molecular weight of from about 300 to about 2,500 are preferred for the purposes of the present invention. The polyether polyols obtained, for example, by the polymerization of tetrahydrofuran are also suitable.

A group of polymers particularly preferred as polyols for the purposes of the present invention are polyurethane polyols. The polyurethane polyols in the context of the present invention are compounds obtainable by polyaddition from difunctional and / or higher alcohols and polyisocyanates. The polyols used for the production of the polyurethanes are typically polyesters and / or polyethers containing at least two hydroxy groups with a molecular weight of about 300 to 10,000 and preferably within a range of about 800 to about 5,000. Polyesters suitable for the production of the polyurethanes suitable for use in accordance with the present invention are any OH-terminated polyester that can react with at least one difunctional isocyanate in a chain extension reaction. These include, for example, the polyesters mentioned above. Other dihydroxy compounds which can be used for the preparation of suitable polyesters as a polyol component for the production of the polyurethanes are, for example, butan-1,3-diol, butan-1,4-diol, butan-2, 3-diol, 2,2-diethylpropan-1, 3-diol, 2-methyl-2-propylpropan-1, 3-diol, isomeric octanediols, ethylenically unsaturated difunctional compounds, such as for example hepteniol, octendiol and difunctional compounds containing heteroatoms (N or S), for example, diethylene glycol, triethylene glycol, thioethylene glycol, diethanolamine or N-methyldiethanolamine or mixtures of two or more of these. To produce the polyurethanes, the diols react Generally with corresponding isocyanates, at least difunctional. The isocyanates used in accordance with the present invention may be aliphatic or aromatic and contain from about 4 to about 40 carbon atoms. Examples of suitable isocyanates are hexamethylene diisocyanate (HDI), 1,8-octane diisocyanate, 1,10-decane diisocyanate, the diisocyanates obtainable, for example, from fatty acid dimerization and corresponding subsequent functionalization, phenylene- 1,4-diisocyanate, tetramethylxylylene diisocyanate (TMXDI), 2,4- and 2,6-toluene diisocyanate and mixtures thereof, 1,5-naphthylene diisocyanate, 2,4,4-diisocyanate or 4,4 '-diphenylmethane (MDI) and mixtures thereof, isophorone diisocyanate (IPDI), cyclobutan-1,3-diisocyanate, cyclohexan-1, 3- and -1,4-diisocyanate, 2,4- and 2-diisocyanate, β-hexahydrotoluene, hexahydro-1, 3- or diisocyanate 1, 4-phenylene, 2,2'-diphenylmethane diisocyanate or 4,4'-diphenylmethane diisocyanate or mixture of two or more of the aforementioned diisocyanates. The trifunctional or higher polyisocyanates obtainable, for example, by the oligomerization of diisocyanates can also be used in accordance with the present invention as the isocyanate required for the production of the polyurethane present in the adhesive A. Examples of such trifunctional and higher polyisocyanates are the triisocyanurates of HDI or IPDI "d mixed triisocyanurates thereof In general, the average molecular weight of the polymer used as polyol should not exceed a value of 400. Since the polymers generally have a statistical molecular weight distribution, according to the method of particular synthesis employed, the term "average molecular weight" refers to the number average molecular weight (Mn) of the polymers present in the adhesive A. This means that individual polymeric molecules with a molecular weight below the value of 400 can also be present. As mentioned above, the adhesive A to be used according to the present invention may also contain one or more other components containing a cationically polymerizable functional group which is not an epoxy group. Examples of such components are olefins, vinyl ethers, vinyl arenes, more particularly styrene, and heterocyclic compounds such as, for example, ethers, thioethers, esters or acetals. Vinyl ethers that can be obtained formally, for example, from the etherification of alcohols, preferably polyols, and vinyl ethers (in fact acetylene is generally used as the initial material in the industrial production of vinyl ethers), and vinyl styrene they are preferably used for the purposes of the present invention. The use of vinyl ethers is especially preferred for the purposes of the invention. Vinyl ethers of suitable low molecular weights with molecular weights of up to about 400 are, for example, monofunctional or difunctional vinyl ethers. Examples of monofunctional or difunctional vinyl ethers are vinyl hydroxybutyl ether, divinyl ether of triethylene glycol, divinyl ether of cyclohexanedi ethanol, propenyl ether of propylene carbonate, dodecyl vinyl ether, monovinyl ether of cyclohexanedimethanol, cyclohexyl vinyl ether, diethylene glycol divinyl ether, vinyl ether 2- ethylhexyl, divinyl dipropylene glycol ether, tripropylene glycol divinyl ether, divinyl hexandiol ether, octadecyl vinyl ether or divinyl butanediol ether representing a preferred compound. Divinyl ethers of higher alcohols can also be used. Examples of such divinyl ethers are glycerol monovinyl ether, glycerol divinyl ether, glycerol trivinyl ether, trimethylolpropane divinyl or trivinyl ether, monovinyl, divinyl, trivinyl or tetravinyl ether of pentaerythritol or vinyl ethers of alcohols containing more than 4 OH groups, for example, vinyl ethers of sugar alcohols. The mentioned compounds can also be used both individually and in the form of a mixture of two or more of the mentioned vinyl ethers. When a relatively high molecular weight compound with molecular weights of about 400 to about 10,000 is employed as the component that additionally reacts cationically, the subject compound is preferably a polymer containing a cationically polymerizable group that is not an epoxy group as a terminal group or, optionally, laterally to the main polymer chain. Compounds of this type, which are preferably used individually or in the form of a mixture in the adhesive to be used according to the present invention, can be obtained, for example, from polyol components of relatively high molecular weights of the type described above. For example, a polymer terminated with vinylstyrene can be prepared by reaction of an OH-terminated polymer with 4-styrene isocyanate. A polyester polyol or polyether polyol or a polyurethane is preferably used as the OH-terminated polymer. It is also possible to prepare a wide variety of polymers containing vinyl ether groups. For this purpose, an OH-containing polymer, for example, reacts with at least a double excess of diisocyanates (based on the OH groups). The resulting polymer, which contains free NCO groups, then reacts with hydroxyvinyl ethers. Polymers containing vinyl ethers can also be prepared by the initial reaction of a vinyl ether containing OH with an equimolar amount of a diisocyanate and by the subsequent reaction of the product of this reaction with an OH-terminated polymer. Preferred OH-containing vinyl ethers for the purposes of the present invention are hydroxybutyl vinyl ether, hydroxyhexyl vinyl ether and cyclohexanedimethanol monovinyl ether. The adhesive A to be used in accordance with the present invention contains the component that reacts cationically without having an epoxy group in an amount of up to 20% by weight, preferably in an amount of 0.1 to about 10% by weight and more preferably in an amount of about 1 to about 8% by weight based on the total adhesive A. The adhesive A to be used according to the present invention contains as photoinitiator a photoinitiator or a mixture of two or more photoinitiators that can initiate the polymerization of the epoxy groups and also of the acrylate groups under the effect of radiation. Particularly suitable photoinitiators are the photoinitiators «that produce Lewis acids or Bronstedt acids under the effect of electromagnetic radiation, more particularly under the effect of light. In accordance with the invention, complex onium compounds are preferably used, such as photoinitiators that produce Lewis acids and / or Brónstedt acids under the effect of light. In principle, any iodonium or photosensitive aromatic sulfonium salt is suitable for the light-induced initiation of the polymerization process. Particularly suitable photoinitiators of this type are hexafluoroantimonatos of trisarilsulfonio, the hexafluorofosfonatos of trisarilsulfonio present, for example, in the commercial products Cyracure UVI-6974 and UVI-6990 (UCC products, Danbury, UK) and tetra- ( pentafluorophenyl) -bis- (4,4'-dimethylbenzyl) -iodonium borate (UV CATA 200, a product of Rhone-Poulenc, Saint-Fons, France). The photoinitiator employed in accordance with the present invention is capable of initiating a radical or cationic polymerization after exposure to light with a wavelength of about 100 to about 600 nm. In a preferred embodiment, the polymerization reaction is initiated by exposure to light with a wavelength of about 150 to about 500 nm, for example, within the range of about 200 to 480 nm. Compounds and mixtures of compounds that can initiate the polymerization of olefinically unsaturated double bonds when exposed to light with a wavelength of about 260 to about 480 nm are used as the photoinitiator, more specifically for radical reaction. In principle, any commercially available photoinitiator that is compatible with the adhesive according to the present invention, ie, which forms at least substantially homogeneous mixtures, can be used for the purposes of the present invention. Photoinitiators commercially available for example any substance fragmentation type Norrish I, for example benzophenone, quinone, camphor, Quantacure (a product of International Bio-Synthetics), Kayacure MBP (a product of Nippon Kayaku), Esacure BO (a product of Fratelli Lamberti), Trigonal 14 (a product of Akzo), photoinitiators of the Irgacure series, Darocure® or Speedcure products Ciba Geigy), Darocure® 1173 and / or Fi-4 (produced by Eastman Company). Among these, Irgacure® 651, Irgacure® 369, Irgacure® 184, Irgacure® 907, Irgacure® 1850, Irgacure® 1173 (Darocure® 1173), Irgacure® 1116, Speedcure EDB, Speedcure ITX, Irgacure 784 or Irgacure ® 2959 or mixtures of two or more of them are especially suitable. Photoinitiators selected from the following group are preferred: benzoin and benzoin derivatives, phenyl hydroxyalkanone types and thioxanthone types.

A photoinitiator with a molecular weight of more than about 200 is used at least partially in a preferred embodiment of the invention. Commercially available photoinitiators that meet this requirement are, for example, Irgacure® 651, Irgacure® 369, Irgacure® 907, Irgacure® 784, Speedcure® EDB and Speedcure® ITX. However, photoinitiators that meet the above requirement in terms of molecular weight can also be obtained by reacting a low molecular weight photoinitiator containing a functional group that reacts with isocyanate, for example, an amino group, or an OH group, with a high molecular weight compound containing at least one isocyanate group (photoinitiators attached to polymers). Compounds that contain more than one photoinitiator molecule, for example, two, three or more photoinitiator molecules, are preferably used as photoinitiators. Compounds such as these can be obtained, for example, by the reaction of a polyfunctional alcohol containing two or more OH groups with suitable diisocyanates or triisocyanates and photoinitiators containing a functional group that reacts with suitable isocyanate. Suitable polyfunctional alcohols are any of the polyfunctional Alcohols mentioned above, but especially neopentyl glycol, glycerol, trimethylolpropane, pentaerythritol and alkoxylation products thereof with C2_4 alkylene oxides. Other suitable polyfunctional alcohols and, in accordance with the present invention, particularly preferred are the products of the reaction of trihydric alcohols with caprolactone, for example, the product of the reaction of trimethylolpropane with caprolactone (Layer 305, a product of Interox, Cheshire, United Kingdom, molecular weight (Mn) = 540). Another preferred embodiment of the present invention is characterized by the use of a photoinitiator which can be obtained by the reaction of at least one trihydric alcohol with caprolactone to form a polycaprolactone containing at least three OH groups with a molecular weight of from about 300 to about 900 and then by linking a polycaprolactone with l- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methylpropan-l-one by means of a compound containing at least two isocyanate groups. Suitable compounds containing at least two isocyanate groups, more particularly suitable diisocyanates, for the reaction with the polyols mentioned are, for example, any of the diisocyanates mentioned in the present specification. However, the 2,4-isomer and the 2,6-isomer of toluene diisocyanate are particularly preferred, the isomers being used either in their pure form or in the form of a mixture. Suitable photoinitiators for the production of photoinitiators linked to polymers are any photoinitiator containing an isocyanate-reactive functional group. 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methylpropan-1-one (Irgacure® 2959), which has a primary OH group, is especially preferred for the purposes of the present invention. The photoinitiators can also be prepared by using a small amount of photoinitiator molecules that react with isocyanate groups in the production of an adhesive A. In this way, the photoinitiator is fixed on a molecule of the adhesive A. The photoinitiator can also be fixed on a polymer chain of the adhesive A by adding the photoinitiator containing a functional group corresponding to the adhesive in a monomeric form and then by reacting it with a corresponding polymer component of the adhesive A as for example during storage of the adhesive. It is also possible to provide the photoinitiator with a polymerizable functional group by exposure to UV light or electron beams, in which case the functional group polymerizable by exposure to UV light or electron beams can be fixed on the photoinitiator, for example, by reaction of the photoinitiator with an unsaturated carboxylic acid. Suitable unsaturated carboxylic acids are, for example, acrylic acid and methacrylic acid. The products of the reaction of Irgacure® 2959 with acrylic acid or methacrylic acid are particularly suitable for the purposes of the invention. Accordingly, a compound that contains both a photoinitiator and a polymerizable functional group by exposure to UV light or electron beams can be used as a photoinitiator. The adhesive A according to the present invention contains the photoinitiator in an amount of up to about 25% by weight, based on the adhesive A globally, the lower limit being about 0.01% by weight. Based on the individual photoinitiator molecule itself (regardless of whether it is covalently bound to another compound), the percentage content in the adhesive should be at least about 0.01% by weight to about 10% by weight, preferably within in the range of about 0.5 to about 5% by weight and more preferably within the range of about 1 to about 3% by weight, based on adhesive A globally. In addition, coinitiators or photosensitizers can also be used, for example, acetophenone, benzophenone and fluorescin and derivatives thereof. In a preferred embodiment, the adhesive A according to the present invention can contain at least one compound having only one polymerizable functional group by exposure to UV light or electron beams as monofunctional reactive diluent. Compounds that are liquid at room temperature, more especially corresponding esters of acrylic or methacrylic acid are especially suitable for this purpose. Particularly suitable compounds are, for example, the esters of acrylic or methacrylic acid of linear or branched, aromatic or aliphatic C4-20 monoalcohols or of the corresponding ether alcohols, for example, n-butyl acrylate, 2-ethylhexyl acrylate. , 3-methoxybutyl acrylate, 2-phenoxyethyl acrylate, benzyl acrylate or 2-methoxypropyl acrylate. The monofunctional reactive diluents make up to about 50% by weight of the adhesive A, but preferably less, for example about 40% by weight, 30% by weight or about 20% by weight. Minor quantities may also be used, such that the adhesive A may contain only 10% by weight, or between about 0.5 and about 8% by weight of the monofunctional reactive diluent. After an initial curing step, for example, by exposure to electron beams or UV rays (in combination with a corresponding photoinitiator), the adhesive A can be cured to the ultimate strength required by the influence of atmospheric moisture. However, if the adhesive must develop a certain ultimate strength at an early stage, ie, if a high curing rate is required, for example, to allow the bonded materials to be processed further as quickly as possible, the speed of Curing achieved by atmospheric humidity can be too slow. In cases of this type, a hardener may be added to the adhesive before processing. Accordingly, the present invention also relates to an adhesive A containing a compound containing at least two acid hydrogen atoms as a hardener. In a preferred embodiment, the hardener is a compound that contains at least two functional groups, each of which with at least one acid hydrogen atom, or a mixture of two or more compounds of this type which are capable of reacting with the corresponding functional groups of the adhesive A. In the context of the invention, the corresponding functional groups of the adhesive A can be any of the functional groups present in the adhesive A which are not polymerizable by irradiation under the conditions according to the invention, more particularly isocyanate groups. Suitable compounds for use as hardeners preferably have a molecular weight of up to 2500. Suitable functional groups with at least one acid hydrogen atom which are reactive with the corresponding functional groups of the adhesive A are, in particular, primary or secondary amino groups, mercapto groups, or OH groups. Suitable compounds for use as hardeners may contain amino groups, mercapto groups or OH groups either exclusively or in mixture with each other. Suitable compounds for use as hardeners generally have a functionality of at least about two. The hardener preferably contains a certain number of compounds of higher functionality, for example, with a functionality of three, four or more. The total functionality (on average) of the hardener is, for example, about 2 (for example where only difunctional compounds are used as a hardener) or more, for example, about 2.1, 2.2, 2.5, 2.7, or 3. The hardener may have optionally an even higher functionality, for example of about four or more. The hardener preferably contains a polyol carrying At least two OH groups. Any of the polyols mentioned in the present specification are suitable for use as the hardener provided they meet the limiting criteria of the upper molecular weight limit. The hardener is usually used in an amount such that the ratio between the functional groups of the adhesive A which react with the hardener and the hardener groups reacting with corresponding functional groups of the adhesive A is from about 5: 1 to about 1: 1 and , more particularly, from about 2: 1 to about 1: 1. A compound containing at least two OH groups is preferably present as the hardener in the adhesive according to the present invention. Adhesive A may optionally contain additives which may constitute up to about 49% by weight of the overall adhesive. Additives that may be employed in accordance with the present invention include, for example, plasticizers, stabilizers, antioxidants, colorants, or fillers. The plasticizers used herein are, for example, plasticizers based on phthalic acid, more especially dialkyl phthalates, the preferred plasticizers are esters of phthalic acid which have been esterified with a linear alkanol containing from about 6 to about 12 carbon atoms. Especially preferred is dioctyl phthalate.Other suitable plasticizers are benzoate plasticizers, for example, sucrose benzoate, diethylene glycol dibenzoate, and / or diethylene glycol benzoate, wherein from about 50 to about 95% of all hydroxyl groups have been esterified, phosphate plasticizers, for example , t-butylphenyl diphenyl phosphate, polyethylene glycols and derivatives thereof, for example, diphenyl ethers of poly (ethylene glycol) liquid resin derivatives, for example, methyl ester of hydrogenated resin, vegetable and animal oils, for example, esters of glycerol of fatty acids and polymerization products thereof. Suitable stabilizers or antioxidants for use, additives according to the present invention include phenols, sterically hindered phenols of high molecular weight (Mn), polyfunctional phenols, phenols containing sulfur and phenols containing phosphorus or amines. Suitable phenols for use as additives according to the present invention are, for example, hydroquinone, hydroquinone methyl ether, 2-, 3- (di-tert-butyl) -hydroquinone, 1,3,5-trimethyl-2, 4 , 6-tris- (3, 5-di-tert-butyl-4-hydroxybenzyl) -benzene; pentaerythritol tetrakis-3- (3, 5-ditert-butyl-4-hydroxyphenyl) -propionate; n-octadecyl-3, 5-ditert-butyl-4-hydroxyphenyl) -propionate; 4, 4-methylene-bis- (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-octylthio) -1,3,5-triazine; di-n-octadecyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphonates; 2- (n-octylthio) -ethyl-3,5-ditert .butyl-4-hydroxybenzoate; and hexa [3- (3, 5-ditert .buil-4-hydroxyphenyl) -propionate)] of sorbitol; and p-hydroxydiphenylamine or N, N '-diphenylenediamine or phenothiazine. Other additives may be incorporated in the adhesive A in order to vary certain properties. These other additives include, for example, dyes, such as for example titanium dioxide, fillers, such as talc, clay and the like. The adhesives according to the present invention may optionally contain small amounts of thermoplastic polymers, for example ethylene / vinyl acetate (EVA), ethylene / acrylic acid, ethylene / methacrylate and ethylene / n-butyl n-acrylate copolymers which provide optionally additional flexibility, hardness, and strength to the adhesive. Certain hydrophilic polymers can also be added, including, for example, polyvinyl alcohol, hydroxyethylcellulose, hydroxypropylcellulose, polyvinyl methyl ether, polyethylene oxide, polyvinylpyrrolidone, polyethylene oxazolines or starch or cellulose esters, more particularly acetates with a degree of substitution. less than 2.5. these hydrophilic polymers increase the humidification capacity of adhesives, for example. The adhesive B may be selected from any of the adhesives known for this purpose. It is preferably a hot melt adhesive or a dispersion adhesive. If the adhesive B is a hot melt adhesive, it contains a) a high polymer base resin of a polyamide, polyurethane and, more particularly, of a copolymer of ethylenically unsaturated monomers, preferably ethylene, with vinyl acetate, acrylic acid and / or methacrylic acid or C este -4 esters of acrylic acid and / or methacrylic acid optionally in combination with b) resins based on dimerized or polymerized, natural or esterified rosin resins, polyterpene resins, phenol / styrene resins, aliphatic and / or aromatic hydrocarbon resins that increase adhesive strength and adhesion and / or c) with waxes and plasticizers. A hot melt adhesive based on ethylene / vinyl acetate copolymers is preferably used. Alternatively, the adhesive B can also be a dispersion adhesive based, for example, on homopolymer or copolymeric polyvinyl acetate dispersions., acrylate dispersions, polyvinylidene dispersions, butadiene / styrene dispersions, polyurethane dispersions, polychloroprene dispersions, and rubber dispersions. In a preferred embodiment, an adhesive based on a dispersion of modified polyvinyl acetate with homopolymer plasticizer is used as this high viscosity dispersion adhesive. Of the adhesive A, a) from 0 to 100% by weight can consist of the component that reacts radically, b) from 0 to 100% by weight of the component that reacts cationically, c) from 0 to 90% by weight of the component containing groups NCO, that is, the three components can be used individually, except in the case of component c) or in combination, that is, in combinations of a + b, a + c, b + c and a + b + c. All these possibilities can be used in the one-step process or in the two-step process together with the adhesive B. The present invention also relates to a process for perfectly binding booklets, books, catalogs, blocks and similar printed articles by means of of a perfect one-step or multi-step binding process, characterized in that the inner book is first coated with a low viscosity crosslinkable adhesive A in a film thickness of less than 0.2 mm, the film is allowed to cure and finally, the adhesive B is optionally applied, the polymer film A also contains at least one photoinitiator. The process according to the present invention is carried out by exposing the adhesive A during or after its application on the edge of the sheet to an electromagnetic radiation with wavelengths less than 600 nm and preferably a UV radiation with wavelengths of approximately 400 nm to 250 nm or X-radiation, electron beam radiation or gamma radiation. The binding process is otherwise substantially unchanged. The claimed adhesive system not only provides advantages in terms of the simple and safe binding of printed articles without significant modifications to the machinery. The printed articles obtained are also less problematic in terms of recycling. To date, adhesives have been so finely reduced in size in residual paper recycling that they could not be removed even with the use of sieves. These "sticky substances", generally thermoplastic, frequently result in the tearing of still wet paper tissues in the dried cylinder during the papermaking process. In the case of the printed articles produced in accordance with the present invention, the adhesive can be easily removed by sieves because the adhesive film has a strength greater than 5 N / mm2. EXAMPLES I. Adhesives Adhesive A: an epoxy adhesive without cationic curing solvent, which can be initiated by UV light, based on a cycloaliphatic epoxy resin and a sulfonium salt as photoinitiator and polyols, namely a triol polyester and a triol polyurethane of MDI, polyetherdiol and polyester diol. Adhesive B: a hot melt adhesive based on EVA, namely 30% EVA, 40% natural resin ester and 30% microcrystalline. II. Procedure An adhesive A was applied at a temperature of 70 ° C on untied internal books (80 g / m2 of paper) in a layer thickness of 0.3 to 0.7 mm. Immediately thereafter, the film was exposed to a UV lamp for about 5 minutes and then heated to a temperature of 70 ° C for about 10 minutes (one step process). After storage for 24 hours at room temperature, the books were subjected to a pulling and bending test. Other books were glued with adhesive B at an application temperature of 170 ° C (two-step process) and then tested. III. Results 1. Pulling and bending values Pulling value bending value in N / cm in WG adhesive A 11.1 1850 (24 h storage) Adhesive A 14.8 2000 + adhesive B IV. Test methods 1. Pull test The page of a fully open book (180 ° C) selected for the test is guided through the opening slit of a Martini pull tester, after which the book is held centrally using the staples present. The page is then held firmly in the provided jaw. The device is switched on and then activated via the "advance" button. The page is then pulled with a growing load until it separates from the binding. The measured values are read and related to the height of the page. The book is then removed and the device returns to its initial position through the "return" key. Normally, 3 to 5 values are determined per book, distributed in the total number of pages, according to the thickness of the book. In this way, differences between the beginning, middle and end can be easily detected. If two or more qualities of paper are used in the same book, the method is adapted accordingly. Classification of pull values: >10 N / cm excellent 8 - 10 N / cm very good 5 - 7 N / cm good 3 - 4 N / cm satisfactory < - 2 N / cm weak 2. Bending test The book is opened at a temperature of 240 ° C and fixed on the table using the spring clips of a bending tester. The test page should be placed exactly on the edge of the table and should be set exactly vertical. In this way, adjacent pages can not support the page that is being tested. Starting with a weight of 200 g per page, 500 laps are completed and recorded by means of a counter. After each cycle of flexion, the weight is increasing by 200 g up to 2000 g / page. The bending cycle test is carried out under this weight. By definition, a bending value of 2000 WG is achieved. This test lasts 45 minutes and provides a total bending count of 500 x 10 = 5,000 with an applied weight increasing from 200 g to 2000 g. The measured bending value is expressed in WG. This unit consists of the cycles of bending and of the applied weight. Calculations: Reading of applied weight 1,600 g Reading of counting of flexions 326 W (1600-200) + 326x200 500 Normally, 3 to 5 values are determined - distributed over the total number of pages, depending on the thickness of the book. In this way, you can easily detect differences between the beginning, the middle and the end of the book. If two or more qualities of paper are used in the same book, the method is adapted accordingly. This method allows a fine differentiation between paper grades, adhesives, processing conditions and binding processes. Classification of values: 1800 - 2000 WG very good 1400 - 1600 WG good 1000 - 1200 WG satisfactory values below 1000 WG may still be acceptable according to requirements, but should be considered as clinical. 3. Viscosity Viscosity is measured in accordance with ASTM D 3236-73 using a Brookfield digital viscometer (Model RVT-DV II) at a speed of 20 to 100 revolutions per minute, and at temperatures within a range of 50 to 100 ° C (axis MK 27). 4. Film resistance Tear resistance (= tensile strength at break point) is determined in accordance with DIN 53455 (ISO 527.2-1985).

Claims

CLAIMS 1. A system of adhesive based on at least one of the adhesive components A and optionally B for a perfect one-step or multistep binding process for books, characterized in that it contains at least one photoinitiator and at least one adhesive A ) which is capable of radiation-induced reaction.
2. An adhesive system according to claim 1, characterized in that the adhesive A is a low viscosity mixture of a monomer and / or polymer that is crosslinkable by applying UV light or stronger electromagnetic radiation and it has a viscosity at the application temperature of 0.100 to 20 Pas and preferably in the range of 0.100 to 10 Pas.
An adhesive system according to claim 1 or claim 2, characterized in that the adhesive A is based on a mixture of aliphatic epoxides and / or on a mixture of acrylate monomers and / or polymers modified by acrylate.
An adhesive system according to claim 1, 2 or 3, characterized in that, in addition to the adhesive A and at least one photoinitiator, it contains another adhesive B having a viscosity at the application temperature of 1 to 20 Pas.
An adhesive system according to at least one of the preceding claims, characterized in that the adhesive B is a) a hot melt adhesive based on a polyamide, polyurethane and, more particularly, a high molecular weight copolymer of ethylenically active monomers unsaturated, preferably ethylene, with vinyl acetate, acrylic acid and / or methacrylic acid or esters of acrylic acid and / or methacrylic acid, optionally in combination with resins that increase the strength of the adhesive and the adhesion based on resins of rosin dimerized or polymerized, natural or esterified, polyterpene resins, phenol / styrene resins, aliphatic and / or aromatic hydrocarbon resins and / or with waxes and plasticizers or b) a dispersion adhesive based on polyvinyl acetate, polyacrylate, polyvinylidene, polyurethane , polychloroprene and rubber dispersions.
6. A process for perfect binding of brochures, catalogs, books, blocks, and similar printed articles through a perfect one-step binding process employing the adhesive system claimed in at least one of claims 1, 2 or 3 characterized in that the inner book is coated with a film of adhesive A.
7. A process for the perfect binding of brochures, catalogs, books, blocks, and similar printed articles, through the process of perfect multi-step binding employing the adhesive system claimed in at least one of claims 1 to 5, characterized in that the internal book first receives a layer of low viscosity crosslinkable film of the additive A of a thickness of less than 0.2 mm and, after curing of the adhesive A, receives finally the adhesive B. A process in accordance with claim 6 or with claim 7, characterized in that, after the application On the edge of the sheet, adhesive A is exposed to electromagnetic radiation with wavelengths less than 600 nm, preferably UV radiation with a wavelength of approximately 400 nm to 250 nm, electron beam radiation , X radiation or gamma radiation. Brochures, catalogs, books, blocks and similar printed articles with the spine stuck with an adhesive system claimed in at least one of claims 1 to 5, characterized in that they have a film strength of the spine adhesive greater than 5 N / mm2.