DD280767A5 - USE OF COREACTIVE PHOTOINITIATORS - Google Patents

Abstract

The invention relates to the use of the compounds of the formula IRGAIN (I) with IN a Fotoinitatorgrundstruktur, A is a spacer group and RG is a functional reactive group and the meanings given herein in the main claim, which can be used as co-reactive photoinitiators for the photopolymerization ethylenically ungesettigte compounds containing systems , which gives particularly advantageous radiation-cured polymers or polymer layers in which photoinitiator residues or photoinitiator degradation products are incorporated in the polymer product so that they can no longer lead to undesirable product changes.

Description

Field of application of the invention

The invention relates to coreactive Fotoinitiatoron for the photopolymerization of ethylenically unsaturated compounds containing systems.

Characteristic of the known state of the art

Photochemically induced polymerisation reactions have gained great importance in the art, especially when it comes to rapid hirting of thin layers, such as thin films. As in the curing of paint and resin coatings on paper, metal and plastic or in the drying of printing inks, as these methods are distinguished from conventional methods for printing and coating of objects by raw material and energy savings and a lower environmental impact. But also the production of ^p olymei materials per se often carried out photochemically by polymerizing appropriate unsaturated monomeric starting materials, which can reach conventional methods such as solution and emulsion polymerizations used.

Since in the reactions mentioned none of the reactants is able to absorb the photochemically active radiation sufficiently, so-called photoinitiators must be added, which are able to absorb either radiated high-energy radiation usually UV light, and thereby forming active starter radicals, which in turn initiate the photopolymerization, or to transfer the absorbed energy for radical formation a <if one of the polymerizable reactants. The initiators do not usually participate in the actual polymerization reaction. Therefore, benzophenone derivatives, benzoin ethers, benzil ketals, dibenzosuberone derivatives, anthraquinones, xanthones, thioxanthones, α-haloacetophenone derivatives, dialkoxyacetophonono and hydroxyalkylphenones have been mainly used as initiators for the photopolymerization of unsaturated compounds. However, the technical applicability of many of the substances mentioned is known to be significantly limited by a number of disadvantages. In particular, this often involves unsatisfactory reactivity in the ability to initiate the photopolymerization of ethylenically unsaturated compounds. In addition to molecule-specific reactivity, in many cases the solubility or very uniform incorporability of the photoinitiators in the photopolymerizable systems plays a decisive role.

Far problems are the dark storage stability of staggered with the Fotointiatoren systems and the possible influence of the end products by residues or degradation products of the photoinitiator. Such residues can, depending on the old and proportion, lead to more or less pronounced influences on the product properties. In the case of photopolymerized lacquer coatings, for example, the main application field for photoinitiators, such radicals can influence the attainable final hardness of the layer; Furthermore, undesirable color changes, for example yellowing, can often occur even after a relatively long time. Initiator residues or their degradation products may be noticeable due to their more or less pronounced volatility due to unpleasant odor; their diffusion out of the coating into surrounding media can create problems, for example, when packaging materials provided with photopolymerized coatings, such as food cans and tubes, are provided. Especially in this field of application, the question of usability is decisively determined by the possible or proven toxicity of the photoinitiators and their degradation products.

A particular problem, especially with regard to a broad application of photoinitiators, is that they can naturally only be used in those systems which essentially contain components with free-radically polymerizable olefinic double bonds.

Thermally curable systems based solely on non-radical-induced polyaddition or polycondensation reactions can not be converted into radiation-curable system by the addition of radical-forming photoinitiators. Accordingly, the choice of materials is limited to components for radiation-curable systems. Many material-specific properties of thermally curable systems can not or can not readily be used in radiation-curable systems. A way out here is with so-called hybrid binder systems in which thermally and photochemically curable components are combined and in which the thermal and the photochemical reaction can take place simultaneously or else in succession. In the development of such systems, however, there are often Kornpatibilitätsprobleme, especially with regard to the photoinitiators to be used. In the professional world was thus

Furthermore οίη special need for photoinitiators, in addition to excellent initiator properties and futer dark storage stability of the staggered system have a wide applicability even in complex composite systems and can embed themselves or their photolysis immigration in such systems. Some steps in this direction have already been taken. For example, DE-OS 3534645 and EPOS 161463 describe photoinitiators of the hydroxyalkylphenone type which carry special olefinically unsaturated substituents. These initiators or their photolysis products can be incorporated into the polymer dressing by copolymerization with the constituents of the radiation-curable system. They can also be first thermally polymerized and then introduced as a polymeric and thus migration-resistant photoinitiator in the radiation-curable system. However, these special copolymerizable or polymeric photoinitiators have only a limited use.

Object of the invention

Radiation-hardened polymers or polymer layers in which photoinitiator residues or photoinitiator degradation products are incorporated into the polymer products so that they are resistant to migration can be obtained particularly advantageously by the use of the invention, so that they can no longer lead to undesired product changes.

Explanation of the essence of the invention

It was therefore an object of the invention to find and provide photoinitiators which should as far as possible be structured in such a way that, in addition to the ability to initiate the polymerization of ethylenically unsaturated compounds by irradiation, they possess the property of any constituents of radiation-curable systems, independently of this whether or not they now participate in the photopolymerization reaction, with the goal of being firmly involved in the resulting polymer dressing

 It has now been found that this is in an excellent manner of compounds of general formula I,

RG-A-IN (I)

where is meant

IN a photoinitiator basic structure

0 6>

-CR ³ R ⁴ R ⁵ or -P (R ⁶ ) ₂ ,

R 'H, C, -) 2-alkyl, halogen, the group RG-A or two carbonyl group ortho radicals R ¹ together also -S-,

R ² H, halogen, Ci-12-All.yl or Ci-12-alkoxy, the group RG-A-,

R ³ , R ^{4 are} each independently H, Ci-12-alkyl, Ci-12-alkenyl, Ci - ^ - alkoxy, phenyl or together C2-6-alkylene,

R ⁶ OR ⁷ , N (R

\ j

R ^{6 is} C 1-4 alkanoyi, phenyl or benzoyl, each optionally substituted by halogen, C 1-6 -alkyl or C 1-8 -alkoxy, R ^{7 is} H.CiHpAlkyloxyC.-e-alkanoyl, A is a spacer group Z ((CH _{2) 0} Y) n - [(CH 2) m X] i

X, Y, Z are each independently equal to a single bond.-O -.- S- or -NH -.- CO -, - COO -, - CONH -, - O-CO-, -NH-CO-, -NH -COO-,

I, m are the numbers 1 to 4,

n, o the numbers O to 4,

RG is one of the functional reactive groups HO-, HS-, H ₂ N-, halogen, HO-CO-, H ₂ N-CO-, O = C = N-, S = C = N-, N ₃ -, SO ₃ H, SO ₂ Cl; R ^c R ^b C = CR "- where R ', R ^b , R ^{c are} each H or CH ₃ and with the proviso that Z is non-COO when η is O and R ⁵ is OR ⁷ ir Halogen, cyclopropyl, oxiranyl, O = C = NR ^d where R ^d is C 1-6 -alkylene or phenylene,

_(with R "equal to halogen, C _ ₁₂ alkyl, C, fulfilled _{1. 12} alkoxy, C ^ n-alkanoyloxy v / ill.

The compounds of the formula I are partly new. These are highly reactive photoinitiators which, irrespective of their photoreactivity, can not undergo photochemically induced (Co) reactions and should therefore be termed coreactive photoinitiators.

Coreactions in the sense of the invention are to be understood as all reactions which involve the photoinitiators or their photolysis products with constituents of radiation-curable systems, with themselves or else with m ^; t the substrate to which this or a corresponding radiation-curable system is applied as a lacquer or coating, and cause a stationary binding of the photoinitiators or their degradation products. These coreactions are primarily reactions in which covalent chemical bonds are formed. But there are also those reactions in which the fixing effect on other interactions, such as ionic or polar interactions, based.

The particular advantage of the compounds according to the invention over conventional photoinitiators results from the presence of the S | acer group A linked reactive group RG, which in addition to the specific photoreactivity this gives the opportunity to take non-photochemical reactions. The variety of reactive groups allows tailor-made adaptation to a wide variety of applications. The coreaction can occur independently of the actual photoreaction before, during or after this.

This surprisingly leads to an unexpectedly high level of incorporation of the unreacted photoinitiators or photoinitiator degradation products into the final polymer product. As a result, undesirable influences on the properties of the end product can be very effectively reduced or completely eliminated.

Furthermore, the fixing of photoinitiators directly on the substrate or in the form of a layer of oligomeric, polymeric or copolymerized photoinitiators affords better anchoring of photopolymerizable coatings applied thereon to the substrate or better layer hardening due to locally particularly high initiator concentrations. Especially in this application, interesting effects and new properties can be achieved.

Many compounds of the formula I are also valuable synthesis intermediates on the way to further functionalized photoinitiators or radiation-reactive systems with covalently incorporated photoinitiator. The invention thus relates to the use of the compounds of the formula I as coreactive photoinitiators for the photopolymerization of ethylenically unsaturated compounds containing systems, in particular in the radiation curing of coatings with UV-curable paint and binder systems, especially hybrid binder systems. The invention also relates to compounds of the formula I per se, insofar as they are new.

The invention further provides a process for the photopolymerization of ethylenically unsaturated compounds containing systems, wherein at least one compound of the formula I nls coreactive photoinitiator is added to the mixture to be polymerized prior to the initiation of the photopolymerization.

The invention further photopolymerizable systems containing at least one ethylenically unsaturated photopolymerizable compound and optionally further known and customary additives, these containing at least one compound c'er formula I as co-reactive photoinitiator.

Gegenstar.u of the invention, finally, the use of compounds of formula I as synthesis intermediates in the preparation of further functionalized photoinitiators and radiation-reactive systems with covalently incorporated photoinitiator.

The compounds of the formula I are derived structurally from known photoinitiators. In formula I, IN stands for any photoinitiator structure which, via nine, in principle, likewise any spacer group A is linked to a functional reactive group RG.

In the compounds of the formula I, photoinitiator properties of the structural part IN with non-photochemically induced reactivity, that is to say coreuity, of the structural part RG are therefore combined

 IN is essentially the aromatic ketone moiety

as present in virtually all classical photoinitiators, but may also mean any other structures with photoinitiator properties.

If R in the aromatic kstone structural unit is an optionally substituted phenyl ring, the photoinitiator of the benzophenone series results. If, in this case, two radicals R ¹ ortho to the carbonyl group together form a sulfur bridge between the phenyl rings, thioxanthone photoinitiators result. Coreactive thioxanthone derivatives are particularly preferred photoinitiators in the context of the invention.

If R stands for the grouping -CR ³ R ⁴ R ^S , then the photoinitiator bases of the benzoin and acyloin ethers, the benzilic and dialkoxyacetophenones, the hydroxyalkylphenones and aminoalkylphenones, as well as the a., Are obtained according to the definitions given above for R ³ , R ⁴ and R ⁵ -Sulfonylketony.

Coreactive hydroxyalkylphenone derivatives are likewise particularly preferred photoinitiators in the context of the invention.

O When R is the group -P (R) ", the resulting photoinitiators belong to the class of acylphosphine oxides.

The spacer group A which links the photoinitiator basic structure IN to the reactive functional group RG preferably has the structure Z [(CH ₂ ) OYln - [(CH ₂ ) m X] i

In the simplest case, when X, Y and Z each represent a single bond, the spacer is an alkylene bridge, preferably having 1 to 8 carbon atoms. The linkage of such einon alkylene group with the aromatic ring of the Fotoinitiptorgrundkörpers can also take place via a heteroatom, when X is -O-, -S- or -NH-. However, the alkylene bridge may also be interrupted by one or more hoteroatomo, which is the case when Y is -O-, -S- or -NH-. Also, interruptions of the alkylene bridge by carbonyl, carboxyl, Carbonsäureamid- or urethane groups are possible. Thus, for example, one or more oxy, thio or aminoalkylene groups can function as spacers, preferably oxyethylene and thioethylene. Mixed heteroalkylene bridges, especially those with oxygen and sulfur as heteroatoms, are also possible. Depending on the chemical nature of the functional reactive group RG, linking them with the spacer group according to the definitions for Z is a single bond, -O-, -S-, -NK- or a carboxyl group or a derivative thereof, such as carboxylic acid amide or urethane group ,

Reactive groups RG are all functional groups which can easily undergo non-photochemically induced reactions. The aim of any such reaction is a fixed integration of the photoinitiator or its photolysis products in the system. Such reactions may be, for example, nucleophilic substitutions by or reversed on the group RG such as esterification, ether formation or acid amide formation. Suitable groups RG are in addition to halogen, in particular chlorine and bromine, especially hydroxyl, thiol, carboxyl and sulfonyl groups and their equivalents. Apart from the halogens, since these functional groups have acidic Η atoms, they can also react with isocyanate groups from the system to form urethanes or urethane analogues. Conversely, the isocyanate group is again a particularly preferred group RG because it can be very easily reacted with components of the system having functional groups with acidic Η atoms.

A! S reactive groups RG are also those which can undergo thermally initiated free-radical or ionic polymerization, polyaddition or polycondensation reactions. These include the vinyl group and its mono- or mono-methylated analogues as well as the cyclopropyl and oxiranyl groups. Isocyanatfurktionalisierte C, _ ₆ alkyl or phenyl groups are examples of pol / addition-enabled groups. Insertion reactions into any of the components of the system can be accomplished by persuasion of carbons or radicals, for example with the azide group as the reactive group RG. For covalent bond formation, the typical reactions of the diazonium group are also suitable. In addition to polysiloxane formation, the silyl group offers, in particular, the possibility of covalent linkage with the substrate, especially if this is of an inorganic nature, such as glass, ceramic, metal. According to the definitions given for photoinitiator basic structure IN, spacer A and reactive group RG, combination of co-reactive photoinitiators with properties tailor-made for the most diverse applications and purposes can be realized by combination. The compounds of the general formula I can be prepared by standard methods of organic chemistry. The reaction conditions here can be taken from the standard works of preparative organic chemistry, for example HOUBEN-WEYL, Methods of Organic Chemistry, Georg-Thieme Verlag, Stuttgart, or ORGANIC SYNTHESIS, J. Wiley, New York / Londoi / Sydney.

In general, it is favorable to prepare the photoinitiators according to the invention or their precursors by the proven synthesis methods which are usual for the known photoinitiators.

It is advantageous to start from the known photoinitiators as starting materials and to tie them to common reactions, such as substitution reactions, in one or more steps, such as spacer group A, and the reactive group RG. However, it is also possible to take suitable substituted precursors of the known photoinitiators and to generate the actual photoinitiator active structure only when spacers and reactive groups are already present.

The compounds of general formula I can according to the invention as photoinitiators for the photopolymerization of ethylenically unsaturated compounds or for the curing of photopolymerizable systems containing such compounds, and in particular as UV curing agent for paint coatings, UV-curable binder and hybrid binder systems, inks and the radiation hardness of aqueous Prepolymei dispersions can be used. This use is done in the usual way. The compounds to be used according to the invention are generally added to the systems to be polymerized in amounts of from 0.1 to 20% by weight, preferably from 0.5 to 12% by weight.

This addition is usually done by simply dissolving and stirring, since most or according to the invention to be used photoinitiators are liquid or at least well soluble in the systems to be polymerized. A mixture of free-radical-initiable mono- or polyfunctional ethylenically unsaturated monomers, oligomers, prepolymers, polymers or mixtures thereof is a system to be polymerized. Oligomers, prepolymers and polymers with unsaturated monomers understood that, if necessary or desirable, other additives such. As antioxidants, light stabilizers, dyes, pigments, but also other known photoinitiators and Reaktionsbeschleuni ger may contain. Unsaturated compounds are all those in Frago whose C =C double bonds are substituted by e.g. Halogen atoms, carbonyl, cyano, carboxy, ester, amide, ether or aryl groups or by conjugated further double or triple bonds are activated. Examples of such compounds are vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, methyl, ethyl, n-or tertertert. Butyl, cyclohexyl, 2-ethylhexyl, benzyl, phenyloxyethyl, hydroxyethyl, hydroxypropyl, lower alkoxyethyl, tetrahydrofurfuryl acrylate or methacrylate, vinyl acetate, propionate, acrylate, succinate, N-vinylpyrrolidone, N-vinylcarbazole , Styrene, divinylbenzene, substituted styrenes, and mixtures of such unsaturated compounds. Polyunsaturated compounds such as, for example, ethylenediacrylate, 1,6-hexanediol diacrylate, propoxylated bisphenyl A-diacrylate and dimethacrylate, trimethylolpropane diacrylate and pentaerythritol triacrylate can also be polymerized with the photoinitiators used according to the invention. Other suitable photopolymerizable compounds are unsaturated oligomers, prepolymers or polymers and mixtures thereof with unsaturated monomers. These include, for example, unsaturated polyesters, unsaturated acrylic materials, epoxy materials, urethanes, silicones, aminopolyamide resins, and especially resins such as acrylated

Silicone oil, acrylated polyesters, acrylated urethanes, acrylated polyamides, acrylated soybean oil, acrylated epoxy resin, acrylated acrylic resin, suitably in admixture with one or more acrylates of a mono-, di-, or polyalcohols. The photopolymerizable compounds or systems can be stabilized by the addition of known thermal inhibitors and antioxidants, such as hydroquinone or hydroquinone derivatives, pyrogallol, thiophenols, nitro compounds, ß-Naphthylamine or ß-naphthols in the usual amounts, without thereby appreciably the initiator effect of the photoinitiators of the invention is impaired. By such additives, above all, premature polymerization during the preparation of the systems by mixing the components should be prevented. Furthermore, small amounts of light stabilizers such as benzophenone derivatives, benzotriazole derivatives, tetraalkylpiperidines or phenyl salicylates can be added.

To exclude the inhibitory effect of atmospheric oxygen, photopolymerizable systems are often added to paraffin or similar waxy substances. Due to lack of solubility in the polymer, they float at the beginning of the polymerization and form a transparent surface layer which prevents the ingress of air. The atmospheric oxygen, for example, by introduction of autoxidable groups such. As allyl groups are deactivated in the system to be cured.

The photoinitiators according to the invention can also be used in combination with known radical initiators, such as, for example, peroxides, hydroperoxides, ketone peroxides or percarboxylic acid esters. Furthermore, they can pigments or dyes, as z. B. in photochemically curing inks are common. In this case, the amount of photoinitiator is set to be higher, for example 6 to 12% by weight, while for colorless photopolymerizable products 0.1 to 5% by weight are sufficient in most cases. Depending on the purpose, fillers such as talc, gypsum or silica, fibers, organic additives such as thixotropic agents, leveling agents, binders, lubricants, matting agents, plasticizers, wetting agents, surface improving silicones, anti-flooding agents, or minor amounts of solvents may be added.

Examples of suitable known photoinitiators which may be used together with the initiators according to the invention are benzophenones, such as, for example, benzophenones. Michler's ketone [4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, p-dimethylaminobenzophenone, p-chlorobenzophenone. benzophenone; Anthraquinones such. Anthraquinone, 2-chloroanthraquinone, 2-alkylanthraquinones; Xanthones such as B. 2-haloxanthones or 2-alkylxanthones; Thioxanthones such as 2-chlorothioxanthone, 2-alkylthioxanthones; Acridanone such. B. 2-alkylacridanones or N-substituted acridanones; Benzions such as B. p-dimethylaminobenzoin and alkyl ethers of benzoin; Benzilketals, a-haloketones, dialkoxyacetophenones, ü-hydroxyalkylphenones and a-aminoalkylphenones as described for example in DE-OS 27 22 264 and in EP-OS 3002, further z. Fluorenones, dibenzosuberones, phenanthrenequinones, benzoic acid esters, e.g. Hydroxypropyl benzoate, benzoyl benzoate acrylate. Mixtures with known initiators contain the coreactive photoinitiators to be used according to the invention as a rule in proportions of at least 10% by weight, advantageously from 50 to 95% by weight, based on the total amount of initiator mixture used.

It is advantageous to use reaction accelerators in addition to the photoinitiators of the invention in the photopolymerizable systems. As such, for example, organic amines, phosphines, alcohols and / or thiols, all of which have at least one α to the heteroatom-containing CH group, are added. Suitable are e.g. primary, secondary and tertiary aliphatic, aromatic, araliphatic or heterocyclic amines, as described, for. As described in US-PS 3,759,807. Examples of such amines are butylamine, dibutylamine, tributylamine, cyclohexylamine, benzyldimethylamine, di-cyclohexylamine, triethanolamine, N-methyldiethanolamine, phenyldiethanolnmin, piperidine, piperazine, morpholine, pyridine, quinoline, p-dimethylaminobenzoic acid, p-Dimethylaminobenzoesäurobutylester, 4.4 'Bis (dimethy! Amino) benzophenone {Michler's ketone) or 4,4'-bis (diethylamino) benzophenone. Particularly preferred are tertiary amines such as trimethylamine, tri-isopropylamine, tributylamine, octyl-dimethylamine, dodecyl-dimethylamine, triethanolamine, N-methyl-diethanolamine, N-butyldiethanolamine, tris (hydroxypropyl) amine, Dimethylaminobenzoesäurealkylester. Further suitable reaction accelerators are, for example, trialkylphosphines, secondary alcohols and thiols. The addition of such reaction accelerators can move in the usual amounts for them.

Photopolymerizable systems which additionally contain a tertiary organic amine as a reaction accelerator constitute a particularly preferred form of the present invention.

The term "photopolymerization of ethylenically unsaturated compounds" is to be understood in the broadest sense, including, for example, the further polymerizing or crosslinking of polymeric materials, such as prepolymers, such as homo-, co- and terpolymerization of simple monomers and also The photopolymerization can be initiated by the action of high-energy radiation, preferably UV light, on the photopolymerizable systems containing the coreactive photoinitiators according to the invention Photopolymerization takes place by irradiation with light or UV radiation of the method known per se Wavelength range of 250-500 nm, preferably 300-400 nm Sunlight or artificial radiators may be used as radiation sources, for example, high pressure mercury vapor, medium pressure or low pressure lamps, xenon and tungsten lamps.

The carrying out of the photopolymerization using the photoinitiators according to the invention can be carried out either batchwise or continuously. The irradiation time depends on the type of implementation, on the type and amount of the polymerizable materials used, on the type and concentration of the photoinitiators used and on the intensity of the light source and can, for example in the radiation curing of coatings, in the range of a few seconds to minutes , in large batches, such as in bulk polymerization, but also in the hourly stomach.

-7- 280 7C7

Di6 compounds of the formula I according to the invention are preferably used as photoinitiators in the UV curing of thin layers such as lacquer coatings on all materials and supports customary for this purpose. These can primarily be paper, wood, textile carriers, plastic and metal. An important field of application is also the drying or curing of printing inks and screen printing materials, the latter of which are preferably used in the surface coating or design of, for example, cans, tubes and metal caps. Due to the largely complete absence of free initiator residues in the coreaktivane photoinitiator systems according to the invention after photopolymerization, these are particularly suitable in application areas where a diffusion of such residues into corresponding end products surrounding media should be excluded, for example when provided with photopolymerized Boschichtungen packaging rungs with food in Come in contact. In the following, the essential components of the coreactive photoinitiators according to the invention, typical representatives, their preparation and preferred method of use are shown

 Compounds of sub-formula II

RG-A

Il 3 4 5

-c-ciririr (id

with the meanings given above for the respective substituents essentially represent the particularly preferred coreactive Fotoirutiatoren of hydroxyalkylphenone type (R ³ , R ⁴ is C 1 - _{) 2} alkyl, R ⁵ is OH) and of the aminoalkylphenone type (R ^{s the} same optionally also alkyl-substituted amino), further coreactive derivatives of benzoin ethers (R ³ is phenyl, R ⁴ is H, C 1 -, _2- alkyl or phenyl, R ⁶ is C, ₁₂ -alkoxy), benzil ketals {R ³ is phenyl , R ⁴ and R ⁶ are C, _i ₂ -alkoxy) and dialkoxyacetophenones (R ³ is H, Cj_ ₁₂ -alkyl, R ⁴ and R ⁵ is C, - _{) 2-} alkoxy). In the preparation of the compounds of formula II in addition to the functionalization of conventional or prepared by known methods conventional photoinitiators especially in the preferred Hydroxvalkylphenon- and aminoalkylphenone derivatives of the preparation of appropriately substituted precursors of the underlying photoinitiators of particular importance, analogous to the known for this purpose Methods are used. These methods are described for example in detail in DE-OS 27 22264 and EP-OS 3002. Coreactive hydroxyalkylphenone derivatives can be obtained, for example, from suitable phenyl derivatives which already contain the spacer group A and functional group RG or corresponding precursors by acylating with a corresponding carboxylic acid halide according to Friedel-Crafts to introduce the photoinitiator active structure or a precursor thereof. As starting materials suitable phenyl derivatives can be, for example, phenol, phenylthiol, phenoxyacetic acid and mono- or polyethoxylated phenol such as 2-hydroxyethyl phenyl ether use. For the Friedel-Crafts acylation, it is in some cases recommended to protect the terminal functional groups by suitable, later removable protective groups, for example by acylation in the case of the OH group. Aniline derivatives can be acylated under Vilsmeier conditions, for example with isobutyric acid Ν, Ν-dimethylamide and phosphorus oxychloride.

To produce the photoinitiator active structure of the hydroxyalkylphenone type, it is possible, for example, to acylate with isobutyric acid halide or a-chloroisobutyric acid halogonide and then introduce the hydroxy, alkoxy or alkanoyloxy group. For example, the Friedel-Crafts Aclierung of acylated 2-hydroxyethyl phenyl ether with isobutyryl chloride and the subsequent bromination and saponification at the tertiary carbon atom to the compound 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone.

HO-CH ₂ CH ₂ -O- / ^) - CC-OH (Ma)

The compound Ma, which is described in itself and as a photoinitiator for aqueous systems already in DE-OS 3E12179, has central importance here, since it is on the one hand due to the terniinalen OH group capable of coreactivity in the context of the invention, on the other hand may also serve as an intermediate for a variety of further derived co-reactive photoinitiators having other functional groups.

This compound is also particularly suitable as a co-reactive photoinitiator in hybrid binding systems. Such systems generally contain at least one thermally and one photochemically curing portion. The thermosetting portion is normally a two or more component reaction resin, preferably of the polyol / polyisocyanate type. Suitable photochemically curing part are all conventional monomeric, oligomeric or polymeric unsaturated compounds and combinations thereof whose polymerization or crosslinking takes place by the influence of onergiereicher radiation and with the aid of the photoinitiator. Such hybrid systems can be obtained by mixing all the components, it being advantageous for the isocyanate components, as is customary for polyurethane-forming reactive resins, to be added shortly before use in order to use premature curing of the thermally polymerizing fraction. To cure with such hybrid systems. These coatings are first irradiated in the usual way for radiation-curing systems, whereby a rapid surface drying and hardening of the layer is achieved. The final hardened state is reached after the end of the thermal reaction, which can also be accelerated by supplying heat. The advantage of these systems compared to the slow-drying systems based purely on reactive thermal resin is the considerable time and energy savings; The coated objects can be stacked immediately or processed faster.

The Vo ₁ IeU the co-active photoinitiators invention as compound II a when used in hybrid binder systems, dβ, in contrast to conventional photoinitiators, in the final cured polymer material virtually no photoinitiator or photolysis products thereof are to be detected, as extraction experiments show. Accordingly, the polymer products show a higher final hardness; Initiation-related negative influences such as odor or yellowing are not recorded. Due to the coreactive OH group, covalent incorporation of the photoinitiator of the invention into the polymer material occurs by reaction with equivalent amounts of the isocyanate component of the thermally curing moiety in the hybrid binder system.

Compound Il a can also be covalently fixed by esterification with components containing carboxylic acid groups in both purely stiahlungshärtbaren and in hybrid systems. Examples of such components are, for example, terephthalic acid, pyromellitic acid or their anhydrides and oligomers or polymers which are derived from these compounds and also have at least one free carboxylic acid function.

Coreactive photoinitiators derived from compound IIa according to the invention are: 4- [2- (oxiranylmethoxy) ethoxy] -phenyl- (2-hydroxy-2-propyl) -1; ethone

O 0 CH ₃

CH ₂ -CH-CH ₂ -O-CH ₂ CH ₂ -O-> ^ VC-C-OH (Hb)

CH ₃ 4- (2-Allyloxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone

Ou I ^J -CC-OH (lic)

CH ₃ 4- [2- (3-triethoxysilylpropoxy) ethoxy] phenyl- (2-hydroxy-2-propyl) ketone

O CH-

O:. jJ -C-C-OH (Hd)

CH ₃

4- (2-aminoethoxy) phenyl (2-hydroxy-2-propyl) ketone

OCH _Q -CC-OH, he)

CH ₃

4- (2-azidoethoxy) phenyl) - (2-hydroxy-2-propyl) ketone

O CH "

Ou I ^J -CC-OH (Hf)

CH ₃

The compounds Hb and Hc can be obtained from Il a by reaction with epichlorohydrin or allyl bromide. Compound ISd is obtainable from lic by subsequent reaction with triethoxysilane.

Precursor He can be prepared, for example, by hydrogenation of Hf.

Compound Hf is obtained by reacting the p-toluenesulfonic acid ester of Ha with sodium azide.

The epoxy-functionalized photoinitiator II b can advantageously be used in particular in hybrid binder systems whose thermally curable fraction is an epoxy-type reactive resin. Due to the epoxy function, Il b or its photolysis products are almost completely incorporated into the epoxy polymor of the binder system.

The unsaturated functionalized photoinitiator lic if t copolymerizable with unsaturated components of any radiation-curable compositions. It can also be thermally polymerized itself. The resulting polymeric photoinitiator may be added to radiation curable compositions where it remains immobile due to its polymeric character. It can also initially be applied only as a polymeric initiator layer on a substrate; an overcoated photohardenable lacquer coating which requires no further initiator additive can then be cured with excellent substrate adhesion.

The silyl-functionalized initiator Il d can be used in an analogous manner, with its application being of particular advantage in the coating of inorganic substrates such as metals, glass or other silicate materials due to the adhesion-improving silyl groups.

Compound Ile can be used analogously to IIa; Compound Il f is highly reactive due to the azido group and is capable, for example, of insertion reactions.

The carboxylic acid-functionalized photoinitiator 4- (hydroxycarbonylmethoxy) phenyl- (2-hydroxy-2-propyl) ketone

O CH "

OK ι-J-C-C-OH (Mg)

CH ₃

allows fixation by typical carboxylic acid reactions such as salt formation, esterification, acid amide formation, etc.

Particularly interesting is the fixation by esterification with macromolecular polyhydroxy compounds such as cellulose and verwi indten materials.

In the case of such modified materials, a very high initiator concentration is superficially achieved, which is very advantageous for the subsequent further modification with photopolymerizable materials, for example in the photoinitiated grafting of monomer toner ("photoproting").

The coreactive photoinitiators can be prepared and used in an analogous manner as the preceding compounds:

4-Allyloxyphenyl- (2-hydroxy-2-propyl) ketone

O CH ,,

Oll I ^J -cc-OH (iih)

CH ₃

4-Oxiranylmethoxyphenyl- (2-hydroxy-2-propyl) ketone

O CH \\ - r-r-

O O CH.

CH ₂ -CH-CH ₀ -O- ^ ^ -CC-OH (Hi)

CH ₃

4- [3- (triethoxysilyl) propoxy] phenyl (2-hydroxy-2-propyl) ketone

0 CH,

VS -r.-c-OU

O -C-C

CH ₃

4- [2- (3-Triethoxysilylpropylthio) ethyl] phenyl- (2-hydroxy-2-propyl) ketone

0 CH,

Oll I ^Λ -CC-OH (Ilk)

CK ₃

4- (2-chloroethoxy) ptienyl- (2-hydroxy-2-propyl) ketone

0 CH,

Cl-CH ₂ -CH ₂ -O- / Vt-I ₁ -Un ( _M)

MOxiranylmethoxyMrbonylmethoxyJphenyl-te-hydroxy ^ -propyDketon

O CH "

Il

CH ₂ -CH-CH ₂ -OC-CH ₂ -O

ι. ι * CH,

4- ^> - <4-methanylmethoxyphenyl (a-isopropoxybenzyl) ketone

O 0 -CH (CH-) _O

Il I - -3 w

CH ₂ -CH-CH ₂ -O-v

4- [3- (triethoxysilyl) propoxy] phenyl (a-isopropoxybenzyl) ketone

0 0 -CH (CH ₃ ).

(C ₂ H ₅ O) ₃ Si (CH ₂ ) ₃ ° C / CH (%)

4-0xirLnylmethoxyphenyl- (a, a-dimethoxybenzyl) ketone

Λ 0 0CH ₀

CH ₀ -CH-CH ₀ -OC ^N ) -CC- * · * · \ - / ι

4- (3- (triethoxysilyl) propoxy] phenyl (a, a-dimethoxybenzyl) ketone

0 OCH,

(C ₀ H ₅ O) ₃ Si (CH ₀ ) ₃ -O- (Vc-C- / ^Ν

OCH,

4- (2-lsocyanatoethoxy) phenyl- (2-hydroxy-2-propvl) ketone

0 CH ₃ O = C = N-CH ₂ -CH ₀ -o / Vc-C-OH

CH ₃ 4- (2-iso-hiocyanatoethoxy) -pienyl- (2-hydroxy-2-propyl) -ketone

O CH ₃ SC = N-CH ₂ -CH ₂ -O- / Vc-C-OH

CH ₃ 4- (2-hydroxy-2-methylpropionyl) phenoxyacetic acid amide

CH ₃ 0

HO-C

(Around)

din)

(Ho)

(UP)

(Hq)

(Mr)

(Ms)

(Mt)

CH,

4- (2-hydroxy-2-methylpropionyl) phtnoxyessigsäurehydrazid

CH_

HO-C C- / Vo-CH ₂ CO-NHNH ₂ (Hu)

CH ₃

N- [4- (2-hydroxy-2-methylpropionyl) phenoxyacetyl) hydroxylamine

CH "

HO-C C- / ¹ V) -O-CH ₂ -CO-NHOH (Hv)

CH ₃

N-I4- ^{(2-Hydroxy-2-methyl-l} propionyl) phenoxyacetyl) N'-Ecryloylhydrazin CH-

I " / -

HO-C C- ( ^ -O-CH ₂ -CO-NHNH-Co-CH = CH ₂

CH ₃

4-lsocyanatomethoxyphenyl- (2-hydroxy-2-propyl) ketone

0 OHL

O "I ^J - CC-OH

CH ₃ 4- (2-hydroxy-2-ir, ethylpropionyl) phenoxyacetic acid vinyl ester

CH-HO-C C- / Vo-CH ₂ -CO-O-CH = CH ₂ (lly)

CH ₃

Compounds of sub-formula III

ti

Y Y S _R 2

"I ^J (Hx)

with the above-mentioned Bade'üungen for the respective substituents represent the also particularly preferred coreactive photoinitiators vor.i trioxanthone type.

Starting materials for this purpose are commercially available thioxanthone photoinitiators or derivatives thereof, which predestinate for simple introduction of the spacer group A and functional groups RG. Particularly suitable as such starting materials are 2-chlorothioxanthone and 2-hydroxythioxanthone.

Reaction of 2-chlorothirone with, for example, 2-mercaptoethanol gives the hydroxy-functionalized photoinitiator 2- (2-hydroxyethylthio) thioxanthone ₁ .11a).

Similarly, the amino-functionalized photoinitiator 2- (2-aminoethylthio) thioxantnone (HIb) is available.

Both compounds can vcIHq analogous to compound Ha as coreactive Fotoinitiato-en, especially in Hybricl-Bindemittelsystemeo used.

Compounds III a and III b can, likewise completely analogous to compounds Ila, also serve as starting material for further corealc.ive photoinitiators with other functional groups. Thus, for example, by reaction with acrylic acid chloride or allyl bromide, the unsaturated functionalized photoinitiators 2- [2- (acryloyloxy) ethylthio] thio. anthon (HIC),

2-I2- (acryloylamino) ethylthio) thioxanthone (HId),

2- (2- (allyloxy) ethylthio) thioxsnthone (IIIe) and

2 | 2- (allylamino) ethylthio] thioxanthone (lllf)

been won.

These compounds are outstandingly suitable as unsaturated components of radiation-suspendable compositions

copolymerizable photoinitiators. However, they can also be thermally polymerized themselves and used as polymeric photoinitiators as described for compound Mc.

By reacting III a with an equivalent amount of a diisocyanate are isocyanate-functionalized photoinitiators such as

2- [2- (6-lsGcyanatohexylaminocarbonyloxy) ethoxy] thioxanthone

O O

Ii κ

O = CN- (CH ₂ ) ₆ -NH-CO-

available. A covalent incorporation into the radiation-curable polymer system can be effected by reaction of the isocyanate group with OH groups of the components. The use in hybrid binder systems which have a polyurethane-forming reactive system as the thermally curing fraction is particularly favorable. Here, the isocyanate-functionalized photoinitiator can be mixed with the isocyanate hardener of the reactive resin component and this mixture can be used, so to speak, as a "hybrid hardener".

In an analogous manner, as described rur ate corresponding compounds of sub-formula II, and epoxy, SiIyI- and carboxylic acid-functionalized thioxanthone Oerivate can be obtained and used accordingly, such as the compounds

2- (oxiranylmethoxy) thioxanthone (HIh) and

2- [3- (triethoxysilyl) propoxy] thioxanthone (Uli).

Aulführungsbeispiele

Example 1 4- (2-Hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (Ha)

a) To 880 g (8.8 mol) of anhydrous aluminum chloride in 480 ml of dichloromethane 336 g (3.2 mol) of isobutyric acid chloride are added dropwise with stirring at -5 to ^{0 0} C within 40 minutes. Thereafter, 540 g (3.0 mol) of 2-Phenoxyetl> ylacetat are added dropwise within 2 hours at the same temperature. The mixture is stirred for a further 2 hours at the indicated temperature and the reaction mixture is poured into a mixture of 1.81 concentrated hydrochloric acid and 5 kg of ice. The organic phase is separated and the aqueous layer is extracted with dichloromethane. The combined organic phases are washed with water, dried, concentrated and the residue is distilled under reduced pressure. This gives 740 g of 4- (2-acetoxyethoxy) phenyl 2-propyl ketone with boiling point 145-152 "C / 0.3-O, 5 Torr.

b) 205 g (1.0 mol) of 4- (2-Acet3xyethoxy) phenyl-2-propyl ketone are dissolved in 200 ml of glacial acetic acid and treated with stirring at 25 ° C within 2 hours with 192g (1.2 mol) of bromine. It is stirred for about 10 hours and then poured into 3I ice water. The product is extracted with ethyl acetate. The combined extracts are dried and concentrated to give 365g of a viscous oil. This is dissolved in 11 ethanol and treated with stirring at 25 ⁰ C within 20 minutes with 380g 32% sodium hydroxide solution. It is stirred for 10 minutes and then the ethanol removed. The oily residue is added to ice-water in 3 l and this mixture is extracted several times with a total of 1.5 l of ethyl acetate. After Trockniin, filtration and concentration of the solution 250 g of oily crude product are isolated. By recrystallization from acetone / petroleum ether and / or chromatographic purification to obtain 145g of 4 - (? - hydroxyethoxy) phenyl (2 hydroxy-2-propyDketon in the form of a colorless solid of Schmelzounkt 88-90 ° C.

Example 2

4- (2-AHyloxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (IIc)

To a mixture of 44.9 g (0.2 mol) of Ha and 8.8 g (0.22 mol) of granulated sodium hydroxide in 300 ml of toluene was added 26.8 g (0.22 mol) of allyl bromide and 1.8 g of methyltrioctylammonium triloride as a phase transfer catalyst, and Stirred at 50 ° C for hours. Thereafter, it is extracted with toluene. Conventional workup and chromatographic purification yield 28.5 g of reagent grade compound Hc.

Example 3

4 | 2- (oxiranylmethoxy) ethoxylphenyl- (2-bydroxy-2-propyl) -koton (IIb)

By reaction analogously to Example 2, but with epichlorohydrin gives compound II b.

Example 4

4- [2- (3-triethoxysilyl-propoxy) -ethoxy) -phenyl- (2-hydroxy-2-propyl) -ketone (lld)

5.3 g (0.02 mol) of compound Hc, 4.9 g (0.03 mol) of triethoxysilane and 20 mg of platinum catalyst (norbornene-Pt-acetylacetonate complex) in 50 ml of methylene chloride are refluxed for 4 hours under nitrogen. After concentration and chromatographic purification of the residue, 3.4 g of analytically pure compound Hd are obtained.

Example 5

4- (Hydroxycarbonylmethoxy) phenyl- (2-hydroxy-2-propyl) ketone (M g) Analogously to Example 1, 931 g (5.6 mol) of methyl phenoxyacetate are obtained by Friodol-Crafts acylation with 657 g (6.2 mol) Isobutyric acid chloride and subsequent bromination and hydrolysis 612 g of compound Hg of melting point

Example 6

4- (2-Hydroxy-2-methylpropionyl) phenoxyacetic acid amide (IIt) 25.2 g (0.1 mol) of methyl 4- (2-hydroxy-2-methylpropionyl) phenoxyacetate (obtained by esterification of compound II g with methanol) in 50 ml Dioxane is added dropwise while stirring with 75, Oq 25% ammonia. After stirring for 2 hours, it is concentrated to solidification. The crude product is recrystallized from water to obtain 22.1 g of compound Mt of melting point 139 ⁰ C.

Example 7

4- (2-azidoethoxy) phenyl- (2-hydroxy-2-propyl) ketone (IIO 37.6 g (0.1 mol) of 4- (2-p-tolylsulfurol / loxyethoxy) phenyl- (2-hydroxy) 2-propyl) ketone (obtained by reacting compound II with a p-Toluolsulfonsäureichlorid) and 9.8 g (0.15mol) of sodium azide are stirred in 100 ml of DMSO at 6O ⁰ C for one hour. Due oxtraktive work-up with water and ether and methyl t-butyl ether gives 22.4 g of compound II f as a light yellow, slightly mobile oil IR: ν = 2114 cm ^-1 (N ₃ ).

Example 8

4-Allyloxyphenyl- (2-hydroxy-2-propyl) ketone (IIh) 36.0 g (0.2 mol) of 4-hydroxyphenyl (2-hydroxy-2-propyl) ketone are added in portions with 6 ml of 450 ml of dimethyl sulfoxide under inert gas , 6g (0.22mol) sodium hydride (807oig in paraffin oil) and stirred for 15 minutes at room temperature. Then 26.3 g (0.22 nv> l) of allyl bromide in 40 ml of dimethyl sulfoxide are added dropwise at 30-40 ° C and stirred for 15 minutes. The reaction mixture is added to 21% water and then extracted with methyl t-butyl ether. Removal of the solvent gives 41.5 g of compound Hh.

Example 9

4-Oxiranylmethoxyphenyl- (2-hydroxy-2-propyl) ketone (II) Analogously to Example 3, 36.0 g (0.2 mol) of 4-hydroxyphenyl- (2-hydroxy-2-propyl) ketone and 19, 0g (0.2 mol) epichlorohydrin 6.8 g reagent grade compound Il i of melting point 54 "C.

Example 10

4- (3- (Triethoxysilyl) propoxy] phenyl- (2-hydroxy-2-propyl) ketone (Hj) Analogously to Example 4, 14.3 g (0.065 mol) of Hg and 16.0 g (0.0975 mol) are obtained. Triethoxysilane 10.2 g of analytically pure compound Hj.

Example 11

2- (2-Hydroxyethylthio) thio; anthone (IIIa) 5.8 g (0.0225 mol) of 2-chlorothioxanthone and 2.6 g (0.0225 mol) of 2-mercaptoethanol potassium salt are dissolved in 20 ml of N, N-dimethylacetamide at 100 for 18 hours ⁰ C stirred. The reaction mixture is then poured into 2N hydrochloric acid and extracted with ethyl acetate. After the usual work-up and purification chromaiographischer 3.5 g of analytically pure compound III is obtained with a melting point of 94 ⁰ C.

Example 12

2- (2-aminoethylthio) thioxanthone (III b) 17.0 g (0.15 mol) of cysteaminium chloride and 19.8 g (0.3 mol) of potassium hydroxide are boiled in 180 ml of toluene for 3 hours in a water separator. The concentrated residue is mixed with 24.6 g (0.1 mol) of 2-chlorothioxanthone and 180ml dimethylpropyleneurea and stirred for 20 hours at 100 ⁰ C. The reaction mixture is poured into 1 1 2 η hydrochloric acid and the aqueous Ph'-se extracted with acetic acid. The aqueous phase is then adjusted to pH 10 ur.d extracted with ethyl acetate. Work-up of the organic phase gives 24.0 g reagent grade compound IH b.

Example 13

2- [2- (Acryloxyloxy) ethylthio] thioxanthone (Hlc) To 14.0 g (0.05 mol) of Compound IHa, 6.0 g of pyridine and 0.07 g of 4-Meihoxyphenol in 150 mL of toluene are added 6.8 g (0.075 mol) of acryloyl chloride in 30 ml of toluene are added dropwise at room temperature with stirring. After 3 hours of stirring at 5O ⁰ C, the mixture is treated with 500ml water and 250ml Essigester. Work-up of the organic phase and chromatographic purification yield 5.0 g of analytically pure compound IHc of melting point 68-71 ° C.

Example 14

2- [2- (Acryloylaminc) ethylthio) thioxanthone (HId) Analcg to Example 10 is obtained from 14.5 g (0.05 mol) of compound IH bund 5.0 g (0.055 mol) of acrylic acid chloride 4.6 g reagent grade compound Hl d with Melting point 161 ⁰ C.

Example 15

Polymeric initiator 18.6 g (0.05 mol) of 2- [2- (acryloxyloxy) ethylthio] thioxanthone (Hle) and 0.15 g of dibenzoyl peroxide are refluxed in 100 ml of toluene for 20 hours. The resulting polymer product is purified by reprecipitation from methylene chloride / n-hexane. A yellow amorphous powder is obtained, whose average molecular weight is determined by gel permeation chromatography to be about 3200.

The following Examples 16-21 illustrate the use according to the invention of the coreactive photoinitiators in the radiation-curing of photopolymerizable binder systems.

Example 16

Hybrid binder star

A hybrid binder system consisting of 40.5 parts by weight of a hydroxy group-containing polyacrylate / about 65% in

Butyl acetate / xylene (Desmophen * A 365, Fa. Bayer AG), 17.0 parts by weight of an aliphatic polyisocyanate / about 75% in

Methoxypropyl acetate / xylene (Desmodur * N 75, Bayer AG), 30.0 parts by weight of an acrylated polyurethane prepolymer (VPS 1748, Degussa AG), 20.0Gew.-Teileri hexanediol diacrylate, 7.5 parts by weight Pentaerythritol triacrylate and 5.0 parts by weight of the hydroxy-functionalized photoinitiator Ma were prepared by mixing the component with the polyisocyanate added just prior to use.

The ready-to-use hybrid binding agent system was applied to glass plates (10 cm × 10 cm) with a spiral doctor blade in a layer thickness of 50 μm. After a flash-off time of ~ 1 minute, the coatings were applied to a UV irradiation device (Beltron), in which the plates were placed on a conveyor at belt speeds between 2.5 and 40 m / min under 50 watt half-height Hg medium pressure lamps. cm performance can be performed at a distance of 10cm, hardened.

At belt speeds of between 2.5 and 15 m / min solid dry paint coatings were immediately obtained.

The thermal postcuring of the polyurethane reactive resin component gave a final hardness of the layers of:

at 20 hours / room temperature: 168 seconds-at 1 hour / 60 ° C: 188 seconds

- at 3 hours / 60 ° C: 198 seconds

(Pendulum hardness after king)

After extraction of fully cured Schichtmatorinl with acetonitrile was determined by HochdrucUflüssigchromatographie the proportion of not incorporated into the material initiator to a maximum of 3% of the original amount. Analogously, equally good results are obtained with the initiators IIIa and IIIb.

Example 17

UV-curable binder system

A UV-curable binder system consisting of 60 parts by weight of an acrylated polyurethane prepolymer (prepolymer SP1748, Degussa AG), 40 parts by weight of hexanediol diacrylate, 15 parts by weight of pentaerythritol triacrylate and 5 parts by weight of the unsaturated functionalized photoinitiator IIc was processed analogously to Example 16 to 50 pm thick coatings and cured at a belt speed of 10m / min. The resulting, fully cured coatings are completely odor-free and colorless

 Analogously, equally good results are obtained with the initiators II h and IIIc-IIIf.

Example 18

UV-curable pigmented binder system

30 parts by weight of titanium dioxide (anatase) were incorporated homogeneously in BOGew parts of an acrylated epoxy prepolymer (Laromer * PE 55 F, BASF AG) and 40 parts by weight of hexanediol diacrylate. Subsequently, 4 parts by weight of the unsaturated functionalized thioxanthone photoinitiator HIc and 8 parts by weight of N-methyldiethanolamine were stirred as a coinitiator. The lacquer, which was applied to glass plates at a layer thickness of 12 μm, hardened to solid coatings with a dry surface at belt speeds of between 2.5 and 20 m / min and a radiation power of 120 W / cm.

At a belt speed of 2.5m / min, the König pendulum hardness is 155 seconds. The paint films are odorless and yellowing.

Example 19

The corresponding use of hydroxy-functionalized thioxanthone photoinitiator III a gave, on curing at 2.5 m / min, resist layers with a pendulum hardness of 149 seconds.

Example 20

UV-curable binder system

50pm thick coatings with a system consisting of 75 parts by weight of an acrylated epoxy prepolymer (Laromer 'EA 81, BASF AG) and 25 parts by weight of hexanediol diacrylate were at a belt speed of 2.5m / min and a radiation power of 80W / cm upon initiation with 0.5C% by weight of the unsaturated-functionalized thioxanthone derivative Hl d and 2.0% by weight of N-methyldiethanolamine hard to coat layers having a pendulum hardness of 172 seconds.

Example 21

Layer hardening with substrate-bound initiator

A 25% ethanolic solution of the silyl-functionalized photoinitiator Hd was spin-coated on glass plates (5 cm × 5 cm) and the plates treated in this way were heated to 190 ° C. for 30 minutes. It was then rinsed with acetone and with

a mixture of 75 parts by weight of an acrylated epoxy prepolymer (Laromer 'EA 81, Fa. BASF AG) and 25 parts by weight of hexanediol diacrylate coated. After UV curing at 3.75 m / min and a radiation power of 120 W / cm and repeated rinsing with acetone hard, very firmly adhering Bo layers were obtained to a thickness of 0.7-0.8pm.

Corresponding results are obtained with the initiator Uj.

Claims (8)

1. Use of the compounds of the formula I, RG-A-IN (I) where is meant IN a photoinitiator basic structure
With 3 4 5
ρ a \\ , -CR RR or - R ^{1 is} H, C 1-10 alkyl, halogen, the group RG-A or two ortho to the carbonyl group Remainders R ¹ together also S, R ² is H, halo, C ^^ - alkyl or C, _ ₁₂ alkoxy group RG-A-, R ^3, R ⁴ are each independently H, C, _ ₁₂ alkyl, C ^^ - kylen alkenyl, C ₁ ^ ₂ -alkoxy, phenyl or together are C ₂ ^ -alkyl, C ₁ N (R ⁷ ) ₂ , -NV -N NH, R ⁵ OR NO, SO.R. ⁷ , R ^{6 is} C 1-6 -alkyl, C 1-4 alkanoyl, phenyl or bonzoyl, each optionally with halogen, Substituted C ₁ -C 4 alkyl or C ₁ -C 4 alkoxy,
R ^{7 is} C 1 -C 4 -alkyl or C 1 -C 4 alkanoyl, A is a spacer group Z [(CH ₂ ) _o YJ _n [(CH ₂ i _m Xli with Χ, Υ, Ζ are each independently of the other a single bond, -0 -, - S or -NH-, -CO-, -COO-, -CONH-, -O-C0-, -NH-CO-, -NH-COO-, I, m are the numbers 1 to 4, η, ο the numbers 0bis4, RG is one of the functional reactive groups HO-, HS-, H ₂ N-, halogen, HO-CO-, H ₂ N-CO-, O = C = N-, S = C = N-, N ₃ -, SO ₃ H, SO ₂ Cl; R ^c R ^b C = CR ^a -where R ^a , R ^b , R ^{c are} each H or CH ₃ and with the proviso that Z is non-COO when η is O and R ⁵ is OR ⁷ ; further halogen, cyclopropyl, oxiranyl, O = C = NR ^d where R ^d g'eich C, _e-alkylene or phenylene, N ₂ - - (R ^e) ₃ Si with R ^e is halogen, C ^^ - alkyl, C ₁ ^ ₂ -alkoxy, C, _ ₁₂ alkanoyloxy, characterized in that the compounds of the formula I are used as coreactive photopolymerization of ethylenically unsaturated compounds containing systems. 2. Use of the compounds of general formula I according to claim 1, characterized in that they are used together with known photoinitiators and / or sensitizers. 3. Use according to claim 1, characterized in that the compounds of formula ί bsi the radiation curing of coatings with UV-curable paint and binder systems are used. 4. Use according to claim 1, characterized in that the compounds of the formula I are used in the radiation curing of hybrid binder systems. 5. A process for the photopolymerization of ethylenically unsaturated compounds containing systems, characterized in that adding at least one compound of formula I as coreactive photoinitiator before the initiation of the photopolymerization of the mixture to be polymerized. 6. The method according to claim 5, characterized in that one adds to the mixture to be polymerized prior to the initiation of the photopolymerization 0.1 to 20 wt .-% of a compound of formula I. 7. Photopolymerizable systems containing at least one ethylenically unsaturated photopolymerizable compound and optionally further known and customary additives, characterized in that they contain at least one compound of formula I as coreactive photoinitiator. 8. Photopolymerizable systems according to claim 7, characterized in that they contain 0.1 to 20 wt .-% of a compound of formula I.