ITMI990376A1 - PIGMENTED PHOTOINDURIBLE COMPOSITION - Google Patents

Description

DESCRIPTION OF THE INDUSTRIAL INVENTION

The present invention relates to pigmented photo-curable compositions which contain photoinitiators consisting of acylphosphine oxides and optical brighteners and which are used in particular as formulations for the coating of white surfaces.

Oxides of mono-, bis- and tris-acylphosphines are known in the literature as photoinitiators, particularly for curing thick pigmented coatings. For example, US 4298738 described oxides of monoacylphosphines and US 4737593 and US 4792632 and furthermore US 5399770 describe oxides of bis-acylphosphines. The latter publication also describes mixtures of oxide photoinitiators of mono- and bis-acylphosphines with α-hydroxyketones and with benzophenones. A description of compounds consisting of tris-acylphosphine oxides can be found in WO 96/07662. EP 741333 discloses a combination of an acylphosphine oxide compound with an optical brightener compound in non-pigmented photopolymerizable compositions in which the reactivity of the composition is increased, which is used in particular in imaging systems.

In the industry there is a need, particularly in the preparation of coatings of pigmented surfaces, for photo-curable formulations which exhibit rapid and complete hardening despite the fact that they have a high pigment content.

It has now been found that upon the addition of optical brightening compounds to pigmented photocurable formulations which contain photoinitiators consisting of acylphosphine oxides, the brightening compounds act as a type of sensitizing agent and unexpectedly the complete hardening of such formulations is improved.

The invention therefore relates to photopolymerizable compositions which contain

(a) at least one ethylenically unsaturated photopolymerizable compound e

(b) as photoinitiator, at least one compound of a mono-, bis- or tris-acylphosphine oxide or a mixture of such a compound or compounds with a compound of an α-hydroxyketone, an α-aminoketone and / or a derivative of benzoin,

(c) at least one optical brightener e

(d) at least one pigment.

Compounds consisting of mono-bis or tris-acylphosphine oxide, for example, are compounds of formula I

in which

R1 and R2, each independently, are C1-C18alkyl; C2-C18alkyl interrupted with one or more non-consecutive oxygen atoms; C1-C4 phenyl-substituted alkyl; C2-C8alkenyl, phenyl, naphthyl, biphenyl or C5-C12cycloalkyl, the phenyl, naphthyl, biphenyl and C5-C12cycloalkyl radicals being unsubstituted or mono- to penta-substituted with halogen, C1-C8alkyl, C1-C8alkylthio and / or with C1-C8alkoxy, or R1 and R2 are -COR3;

R3 is phenyl which is unsubstituted or is mono- to penta-substituted with C1-C12alkyl, C1-C12alkoxy, C1-C12alkylthio and / or with halogen.

Compounds consisting of α-hydroxyketone, α-aminoketone and benzoin derivative are compounds of formula II

m which

R4 is hydrogen, C1- Ciealkyl, C1-C18alkoxy, CH-I <3> -OCH2CH2-OR8, morpholino, SCH3, an H2C = C- group

or a group

n has a value between 2 and 10;

G is the radical

R5 is hydroxy, C1-C16alkoxy, morpholino, dimethylamino or -O (CH2CH20) m-C1-C16alkyl;

R6 and R7, each independently, are hydrogen, C1-C6alkyl, phenyl, benzyl, C1-C6alkoxy or -O (CH2CH2O) m-C1-C16alkyl, or R6 and R7, together with the carbon atom to which they are bonded, they form a cyclohexyl ring;

m is a number between 1 and 20;

however R5, R6 and R7 are not all C1-C16alkoxy or -O (CH2CH2O) m-C1-C16alkyl at the same time; And

R8 is hydrogen, or

C1-C18alkyl is linear or branched and, for example, is C1-C12-, C1-C8-, C1-C6- or C1-C4alkyl. Examples are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, 2,4,4-trimethylpentyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl. C1-C12alkyl, C1-C8alkyl and C1-C6alkyl are equally linear or branched and, for example, have the meanings mentioned above up to the corresponding number of carbon atoms.

C2-C18alkyl interrupted once or several times with non-consecutive oxygen atoms is interrupted, for example, from 1 to 7 times or once or twice, with -O-. The oxygen atoms are separated from each other (from others) by at least one methylene group which, for example, result in structural units such as the following: -CH2-O-CH3, -CH2CH2-O-CH2CH3, - [CH2CH2O] y-CH3 where y = 1 to 8, - (CH2CH2O) 7CH2CH3, -CH2-CH (CH3) -O-CH2-CH2CH3 or -CH2-CH (CH3) -O-CH2-CH3.

C1-C18alkoxy is a linear or branched radical and, for example, is C1-C12-, C1-C8-, C1-C6-or C1-C4alkoxy. Examples are methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy, sec-butyloxy, isobutyloxy, tert-butyloxy, pentyloxy, hexyloxy, heptyloxy, 2,4,4-trimethylpentyloxy, 2-ethylhexyloxy, octyloxy, nonyloxy, decyloxy, dodecyloxy, hexadecyloxy and octadecyloxy, in particular methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy, sec-butyloxy, isobutyloxy and tert-butyloxy, preferably methoxy. C1-C12alkoxy, C1-C8alkoxy, C1-C6alkoxy and C1-C4alkoxy are equally linear or branched and, for example, have the meanings mentioned above up to the corresponding number of carbon atoms.

C1-C12alkylthio is a linear or branched radical and, for example, is C1-C8-, C1-C6- or C1-C4alkylthio, for example methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, sec-butylthio, isobutylthio, tert -butylthio, pentylthio, hexylthio, heptylthio, 2,4,4-triraethylpentylthio, 2-ethylhexylthio, octylthio, nonylthio, decylthio or dodecylthio, in particular methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, sec-butylthio, isobutylthio or tert -butylthio, preferably methylthio. C1-C8alkylthio is likewise linear or branched and, for example, has the meanings mentioned above up to the corresponding number of carbon atoms.

C5-C12 cycloalkyl, for example, is cyclopentyl, cyclohexyl, cyclooctyl or cyclododecyl, in particular cyclopentyl or cyclohexyl, preferably cyclohexyl.

C2-C8alkenyl radicals can be mono or polyunsaturated and can be linear or branched and are, for example, C2-C6- or C2-C4-alkenyl. Examples are allyl, metallyl, 1,1-dimethylallyl, 1-butenyl, 2-butenyl, 1,3-pentadienyl, 1-hexenyl and 1-octyl, in particular allyl. C1-C4-phenyl-substituted alkyl in particular is benzyl.

Substituted phenyl, naphthyl or biphenyl are from mono- to penta-substituted on the phenyl ring, for example they are mono-, di- or tri-substituted, in particular mono- or di-substituted. R3 as substituted phenyl in particular is di- or trisubstituted. Preferred substituents of R1, R2 and R3 such as phenyl, naphthyl and biphenyl are C1-C4-alkyl, in particular methyl, C1-C4-alkoxy, in particular methoxy and chlorine. A particularly preferred meaning of R3 is, for example, 2,4,6-trimethylphenyl, 2,6-dimethylphenyl or 2,6-dimethoxyphenyl.

Halogen is fluorine, chlorine, bromine or iodine, in particular chlorine or bromine, preferably chlorine.

The preparation of the compounds of formula I is known to those skilled in the art and is described, for example, in US 4298738, 4737593 and 4792632, GB 2259704 and WO 96/07662. Some of these compounds are commercially available. Some compounds of formula II are also commercially available. Their preparation is carried out according to known methods and is described, for example, in EP 3002, EP 284561 and EP 805152. The preparation of oligomeric compounds of formula II is described, for example, in EP 161463.

Preferred are compositions in which, in the compounds of formula I, R1 and R2, each independently, are C1-C18alkyl; C2-C18alkyl interrupted with one or more non-consecutive oxygen atoms; C1-C4 phenyl-substituted alkyl; C2-C8alkenyl, phenyl, naphthyl, biphenyl or C5-C12cycloalkyl, the phenyl, naphthyl, biphenyl and C5-C12cycloalkyl radicals being unsubstituted or mono- to pentasubstituted with halogen, C1-C8alkyl, C1-C8alkylthio and / or con C1-C8alkoxy; and R3 is phenyl which is unsubstituted or is mono- to penta-substituted with C1-C12alkyl, C1-C2alkoxy, C1-C12alkylthio and / or with halogen.

In further preferred compositions according to the invention the compounds of formula I are monoacylphosphine oxides.

In other preferred compositions R1 and R2, in the compounds of formula I, each independently, are C1-C18alkyl, or phenyl which is unsubstituted or is mono- to penta-substituted with halogen, C1-C8alkyl, C1-C8alkylthio and / or with C1-C8alkoxy.

There are also interesting compositions in which R3, in the compounds of formula I, is phenyl which is di-substituted or tri-substituted with C1-C12alkyl or with C1-C12alkoxy.

Further preferred compositions are those in which, in the compounds of formula II

R4 is hydrogen, -OCH2CH2-OR8, morpholino or SCH3; R5 is hydroxy, C1-C16alkoxy, morpholino or dimethylamino; R6 and R7, each independently, are C1-C6alkyl, benzyl or C1-C16alkoxy, or R6 and R7, together with the carbon atom to which they are bonded, form a cyclohexyl ring;

however R5, R6 and R7 are not all C1-C16alkoxy at the same time; And

R8 is hydrogen.

Particularly preferred are also compositions in which the compound of formula II is an α-hydroxyketone.

Preferred compounds of formula II are α-hydroxycyclohexylphenyl-ketone and 2-hydroxy-2-methyl-1-phenyl-propanone, (4-methylthiobenzoyl) -1-methyl -1-morpholino-ethane, (4-morpholino-benzoyl) - 1-benzyl-1-dimethylamino-propane and benzyl-dimethylketal.

Preferred compounds of formula I are oxide of (2, 4, 6-trimethylbenzoyl) -diphenyl-phosphine, oxide of bis (2,6-dimethoxybenzoyl) - (2,4,4-trimethylpent-1-yl) -phosphine, oxide bis (2,4,6-trimethylbenzoyl) -phenyl-phosphine and bis (2,4,6-trimethylbenzoyl) - (2,4-dipentyloxyphenyl) -phosphine oxide.

Also preferred are compositions in which, in formula II, R6 and R7, each independently, are C1-C6alkyl or, together with the carbon atom to which they are bonded, form a cyclohexyl ring, and R5 is hydroxy.

Also important are compositions in which, in the compounds of formula II, R6 and R7 are identical and are methyl, and R5 is hydroxy or isopropoxy.

The proportion of the compounds of formula I mixed with compounds of formula II is between 5 and 99%, for example between 20 and 80%, preferably between 25 and 75%.

Also of interest are compositions, as described above, which contain mixtures of photoinitiators of formulas I and II which are liquid at room temperature.

The compositions according to the invention contain at least one optical brightener, ie they can contain one or more, for example one or two of such compounds. The optical brighteners to be used as component (c) in the composition according to the invention can derive from a large variety of classes known in the art. Suitable, for example, are those selected from the groups of pyrazolines, stilbenes, for example 4,4'-bis (diphenyltriazinyl) stilbene, triazines, thiazoles, benzoxazoles, xanthones, triazoles, for example stilbenyl-naphthotriazole, oxazoles, for example bis (benzoxazo1-2-yl} -derivatives, thiophenes, for example bisbenzoxazolyl-thiophenes, and coumarins. Further examples can be found in US 2784183 and US 3644394. Examples are also found in R.L. Alien, Color Chemistry, pages 278-286, Nelson, 1971. Preferred 2,2'- (thiophenediyl) -bis (tert-butyl-benzoxazole), phenyl ester of 2- (stilbil-4 ") - (naphtho-1 < T>, 2 ', 4,5) -1,2,3-triazole-2 "-sulfonic, 7- (4'-chloro-6" -diethylamino-1', 3 ', 5'-triazin-4' -yl) -amino-3-phenyl-coumarin and 2,5-bis (6,6'-bis (tert-butyl) -benzoxazol-2-yl) -thiophene.

Optical brighteners, in particular, are compounds of formula III

whose

X is a group

And

R9, R10, R11 and R12, each independently, are hydrogen, C1-C8alkyl; C1-C8alkyl substituted with -COO-C1-C8alkyl, in particular with -COOCH3 or with -COOCH2CH (C2H5) C4H9; -COO-C1-C20alkyl or a, α-dimethylbenzyl.

Compounds of formula III are preferred, in which

X is a group

or and

R9, R10, R11 and R12, each independently, are hydrogen, methyl, tert-butyl, -COO-C1-C20alkyl or α, α-dimethylbenzyl.

In particular they are preferred

And

wherein R15

is

Further preferred optical brightener compounds are

Optical brightening compounds are known to those skilled in the art and are widely commercially available, for example under the brand name "UVITEX" of the company Ciba Spezialitatenchemie, Switzerland. In particular, ®UVITEX OB (Ciba Spezialitatenchemie, Switzerland) is preferred.

The optical brighteners (c) are added to the compositions according to the invention advantageously in

an amount comprised between 0.05% and 2.0%, preferably in an amount comprised between 0.2% and 1.0%.

Preferred are compositions which contain as component (b) a compound of formula I, in which R1 and R2 are phenyl and R3 is C1-C4alkyl-substituted phenyl or which contain as component (b) a mixture of a compound of formula I, in wherein R1 and R2 are phenyl and R3 is C1-C4alkyl-substituted phenyl and of a compound of formula II, in which R4 is hydrogen, R5 is hydroxy and R6 and R7 are each C1-C4alkyl or together form a cyclohexyl ring; which contain as component (c) a compound of formula III, in

where X is a radical, R10 and R12 are hydrogen and

R9 and R11 are each tert-butyl; and contain as component (d) a titanium dioxide pigment.

Particularly preferred compositions containing

and a blend

1: 1 oxide of 2, 4, 6-trimethylbenzoyl-diphenyl-phosphine and 2-hydroxy-2-methyl-1-phenyl-propanone;

®UVITEX OB and 2, 4, 6-trimethylbenzoyl-diphenylphosphine oxide;

®UVITEX OB is a 1: 1 mixture of (2,4,6-trimethylbenzoyl) -diphenyl-phosphate and di (1-hydroxycyclohexyl) -phenyl-ketone oxide;

®UVITEX OB is a 1: 1 mixture of (2,4,6-trimethylbenzoyl) -ethoxy-phenyl-phosphate and (1-hydroxycyclohexyl) -phenyl-ketone oxide; And

®UVITEX OB is a 1: 1 mixture of

and di (1-hydroxycyclohexyl) -phenyl-ketone.

The unsaturated compounds (a) can contain one or more olefinic double bonds and can be of low molecular weight (monomers) or of higher molecular weight (oligomers). Examples of monomers that have a double bond are alkyl- and hydroxyalkyl acrylates and methacrylates, such as, for example, methyl-, ethyl-, butyl-, 2-ethylhexyl- and 2-hydroxyethyl-acrylate, isobornyl-acrylate and methyl- and ethyl- methacrylate. Silicone-acrylates are also interesting. Further examples are acrylonitrile, acrylamide, methacrylamide, N-substituted (meth) acrylamides, vinyl esters such as vinyl acetate, vinyl ethers, such as isobutylvinylether, styrene, alkyl- and halogen-styrenes, N-vinylpyrrolidone, vinyl chloride and vinylidene chloride.

Examples of monomers that have several double bonds are ethylene glycol acrylate, propylene glycol acrylate, neopentyl glycol acrylate, hexamethylene glycol acrylate, bisphenol-A diacrylate, 4, 4 '-bis (2-acryloxyethoxy) -diphenylpropane, acrylate tri-propylene triacrylate, tri-acetylacrylate tri-acrylate tri , vinyl acrylate, divinylbenzene, divinyl succinate, diallylfthalate, triallylphosphate, triallylisocyanurate and tris (2-acryloethyl) isocyanurate.

Examples of polyunsaturated compounds of higher molecular weight (oligomeric) are acrylate epoxy resins, polyesters, polyurethanes and polyethers acrylates or containing vinyl ether groups or containing epoxy groups. Further examples of unsaturated oligomers are unsaturated polyester resins which are usually prepared from maleic acid, phthalic acid and one or more diols and which have molecular weights between about 500 and 3000. It is also possible to use vinyl ether monomers and oligomers. and also oligomers terminated with maleate groups, having main chains of polyester, polyurethane, polyether, polyvinyl ether and epoxide. Combinations of oligomers and polymers carrying vinylether groups, as described in WO 90/01512, are particularly well suited. However, copolymers of monomers functionalized with vinylether or with maleic acid are also suitable. Such unsaturated oligomers can also be referred to as prepolymers.

Particularly suitable are, for example, esters of ethylenically unsaturated carboxylic acids and polyols or polyepoxides, and polymers having ethylenically unsaturated groups in the chain or in side groups, such as, for example, polyesters, polyamides and unsaturated polyurethanes and their copolymers, alkyd resins, polybutadiene and copolymers of butadiene, polyisoprene and isoprene copolymers, polymers and copolymers having (meth) acrylic groups in the side chains, and mixtures of one or more of such polymers.

Examples of unsaturated carboxylic acids are acrylic acid, methacrylic acid, crotonic acid, itaconic acid, cinnamic acid and unsaturated fatty acids, such as linolenic acid or oleic acid. Acrylic acid and methacrylic acid are preferred.

Suitable polyols are aromatic and, in particular, aliphatic and cycloaliphatic polyols. Examples of aromatic polyols include hydroquinone, 4,4'-dihydroxydiphenyl, 2,2-di (4-hydroxyphenyl) propane, as well as novolacs and resoles. Examples of polyepoxides are those based on the polyols mentioned, in particular of the aromatic polyols and of epichlorohydrin. Also suitable as polyols are polymers and copolymers that contain hydroxyl groups in the polymer chain or in side groups, such as, for example, polyvinyl alcohol and its copolymers, and hydroxyalkyl esters of polymethacrylic acid and their copolymers. Further suitable polyols are oligoesters having terminal hydroxyl groups.

Examples of aliphatic and cycloaliphatic polyols include alkylene diols preferably having from 2 to 12 carbon atoms, such as ethylene glycol, 1,2- and 1,3-propanediol, 1,2-, 1,3- and 1,4-butanediol, pentandiol, hexandiol, octanediol, dodecandiol, diethylene glycol, triethylene glycol, polyethylene glycols having a molecular weight preferably between 200 and 1500, 1,3-cyclopentanediol, 1,2-, 1,3-and 1,4-cyclohexanediol, 1,4- dihydroxymethylcyclohexane, glycerol, tris (β-hydroxyethyl) amine, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol and sorbitol.

The polyols can be partially or completely esterified with one or several unsaturated carboxylic acids, it being possible that the free hydroxyl groups in the partial esters are modified, for example etherified, or esterified with other carboxylic acids.

Examples of esters are given below: trimethylolpropane triacrylate, trimethylolethane triacrylate, trimethylolpropane trimetacrylate, trimethylolethane trimethacrylate, tripropylene glycol diacrylate, trimethylolethane trimethacrylate, tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetramethylene glycol dimethacrylate, polyethylene glycol dimethacrylate , dipentaeritritol diacrilato, dipentaeritritol triacrilato, dipentaeritritol tetraacrilato, dipentaeritritol pentaacrilato, dipentaeritritol esaacrilato, tripentaeritritol ottaacr ilato , pentaeri tritol dimetacrilato, pentaeritritol trimetacrilato, dipentaeritritol dimetacrilato, dipentaeritritol tetrametacrilato, tripentaeritritol ottametacrilato, pentaeritritol diitaconato, dipentaeritritol trisitaconato, dipentaeritritol pentai taconato, dipentaeritritol esaitaconato , etilenglicol diacrylate, 1, 3-butanediol diacrylate, 1, 3-butanediol dimethacrylate, 1, 4-butand diitaconate iol, sorbitol triacrylate, sorbitol tetraacrylate, pentaerythritol-modified triacrylate, sorbitol tetramethacrylate, sorbitol pentaacrylate, sorbs tol hexacrylate, acrylate and methacrylate of oligoesters, glycerol di- and tri-acrylate, dia. polyethylene glycol having a molecular weight between 200 and 1500, and mixtures thereof.

Also suitable as component (a) are the amides of identical or different unsaturated carboxylic acids of aromatic, cycloaliphatic and aliphatic polyamines, preferably having from 2 to 6, in particular from 2 to 4 amino groups. Examples of such polyamines are ethylenediamine, 1,2- and 1,3-propylenediamine, 1,2-, 1,3- and 1,4-butylenediamine, 1,5-pentylenediamine, 1,6-hexylenediamine, octylenediamine, dodec1endiamine. , 1,4-diaminocyclohexane, isophorondiamine, phenylenediamine, bisphenylenediamine, di-β-amino ethyl ether, diethylenetriamine, triethylenetetramine, di (β-aminoethoxy) - and of (β— aminopropoxy) ethane. Further suitable polyamines are polymers and copolymers which may have further amino groups in the side chain and oligoamides having terminal amino groups. Examples of such unsaturated amides are: methylene bisacrylamide, 1.6-hexamethylene bisacrylamide, diethylenetriamine trismethacrylamide, bis (methacrylamidopropoxy) ethane, β-methacrylamidoethyl methacrylate and N - [(β-hydroxyethoxy) ethyl] acrylamide.

Suitable unsaturated polyesters and polyamides are derived, for example, from maleic acid and diols or diamines. Maleic acid can be partially replaced with other dicarboxylic acids. They can be used in conjunction with ethylenically unsaturated comonomers, for example styrene. The polyesters and polyamides can also be derived from dicarboxylic acids and ethylenically unsaturated diols or diamines, particularly those having longer chains, for example, of 6 to 20 carbon atoms. Examples of polyurethanes are those which consist of saturated diisocyanates or unsaturated diisocyanates and unsaturated diols or saturated diols.

Polybutadiene and polyisoprene and their copolymers are known. Suitable comonomers include, for example, olefins, such as ethylene, propene, butene, hexene, (meth) acrylates, acrylonitrile, styrene and vinyl chloride. Polymers having (meth) acrylate groups in the side chain are also known. Examples are reaction products of novolac-based epoxy resins with (meth) acrylic acid; homopolymers or copolymers of vinyl alcohol or its hydroxyalkyl derivatives which have been esterified with. (meth) acrylic acid; and homopolymers or copolymers of (meth) acrylates which have been esterified with hydroxyalkyl (meth) acrylates.

The photopolymerizable compounds can be used as such or in the form of any desired mixture. Mixtures of polyol (meth) acrylates are preferably used.

The binding agents can be added to the compositions according to the invention, this being particularly suitable when the photopolymerizable compounds are liquid or viscous substances. The amount of binding agent, for example, can be 5-95% by weight, preferably 10-90% by weight and, in particular, 40-90% by weight, referred to the total solid products. The choice of the binding agent is made according to the sector of use and according to the properties required for this sector, such as adhesion on substrates and sensitivity to oxygen.

Suitable binding agents are, for example, polymers having a molecular weight comprised between about 5,000 and 2,000,000, preferably between 10,000 and 1,000,000. Examples are: homopolymers and copolymers of acrylates and methacrylates, e.g. copolymers of methyl methacrylate / ethyl acrylate / methacrylic acid, poly (alkyl esters of methacrylic acid}, poly (alkyl esters of acrylic acid); esters and ethers of cellulose, such as acetate cellulose, cellulose acetate-butyrate, methylcellulose, ethylcellulose; polyvinyl butyral, polyvinyl formal, cyclized rubber, polyethers, such as polyethylene oxide, polypropylene oxide, polytetrahydrof urane; polystyrene, polycarbonate, polyurethane, chlorinated polyolefin / vinyl chloride, polyvinyl chloride, polyvinyl chloride , copolymers of vinylidene chloride with acrylonitrile, methyl methacrylate and vinyl acetate, polyvinyl acetate, copolys (ethylene / wine lactate), polymers such as polycaprolactam and poly (hexamethylene adipamide), polyesters such as poly (ethylene glycolterephthalate) and poly (hexamethylenglycolate).

The unsaturated compounds can also be used in admixture with non-photopolymerizable film forming components. These can be, for example, polymers which can be physically dried or their solutions in organic solvents, such as, for example, nitrocellulose or cellulose acetobutyrate. However, as an alternative, they can be chemically or thermally curable resins, such as, for example, polyisocyanates, polyepoxides or melamine resins. step and are crosslinked by heat post-treatment in a second step.

Compositions which do not contain any binding agent are preferred.

The compositions according to the invention are also suitable in systems drying by oxidation, as described, for example, in Lehrbuch der Lacke und Beschichtungen, Volume III, 296-328, publisher W.A. Colomb of Heenemann GmbH, Berlin-Oberschwandorf (1976).

The compositions according to the invention contain at least one pigment 8d), ie they contain a pigment or two or more different pigments, for example from one to three pigments or one or two pigments. In the compositions according to the invention the pigments can be inorganic or organic. Black, white or colored pigments can be used. Examples of pigments include white pigments of the rutile type, such as ®RTC-2 from Tioxide, carbon black, such as © Special Black 250 from Degussa, diketopyrrole-pyrrole, such as © IRGAZIN DPP Red Bo from Ciba Specialty ChemicaAs, isoindolinones, such as © IRGAZIN Yellow 3RLTN from Ciba Specialty Chemicals, ariamides, such as ®IRGALITE Yellow Gu from Ciba Speciaìty Chemicals, cupro-phthalocyanine, such as ®IRGALITE Blue GLNF from Ciba Speciaìty Chemicals and cupro-phthalocyanine (halogenated), such as ®IRGALITE Green GLNnew from Ciba Speciaìty Chemicals.

As component (d), in the compositions according to the invention, it is preferable to use a white pigment, for example of the titanium dioxide type.

The photopolymerizable compositions according to the invention usually contain the pigment or pigments (d) in an amount of between 5% and 50%, for example between 10% and 50%.

Light-cured mixes may contain several additives (s) in addition to the photoinitiator. Examples of additives are thermal inhibitors which have the purpose of preventing premature polymerization, such as, for example, hydroquinone, hydroquinone derivatives, p-methoxyphenol, β-naphthol or phenols with steric hindrance, such as, for example, 2,6 -di (tertbutyl) -p-cresol. To increase the storage stability in the dark, for example, copper compounds such as naphthenate, stearate or copper octanoate, phosphorus compounds, such as, for example, triphenylphosphine, tributylphosphine, triethylphosphite, triphenylphosphite or tribenzylphosphite, compounds of quaternary ammonium, such as, for example, tetramethylammonium chloride or trimethylbenzylammonium chloride, or hydroxylamine derivatives, such as, for example, N-diethylhydroxylamine. For the purpose of excluding atmospheric oxygen during polymerization, paraffin or similar wax-like substances can be added which, being insoluble in the polymer, migrate to the surface at the start of polymerization and form a transparent surface layer which prevents the entry of the 'air. Likewise, it is possible to apply a layer which is impermeable to oxygen. As stabilizing agents towards the light, substances which absorb UV rays, such as, for example, those of the type hydroxyphenylbenzotriazole, hydroxyphenylbenzophenone, oxalic acid amide or hydroxyphenyl-s-triazine can be used. Such compounds can be used alone or in the form of mixtures, with or without the use of steric hindered amines (HALS).

Examples of such UV absorbing substances and photostabilizers are given below:

1. 2- (2'-hydroxyphenyl) -benzotriazoles, e.g. 2- (2'-hydroxy-5 <,> - methylphenyl) -benzotriazole, 2- (3 ', 5'-ditert-butyl-2'-hydroxyphenyl) - benzotriazole, 2- <5'- tertbutyl-2'-hydroxyphenyl) -benzotriazole, 2- (2'- hydroxy-5 '- (1, 1, 3, 3- tetramethylbutyl) phenyl) -benzotriazole, 2- (3 ', 5' - ditert-butyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3 * - tert-butyl-2'-hydroxy-5'-methylphenyl) -5-chlorobenzotriazole, 2- (3'- sec-butyl-5'-tert-butyl-2'-hydroxyphenyl) -benzotriazole, 2- (2'-hydroxy-4'-octyloxyphenyl) -benzotriazole, 2- (3 ', 5'-di-tert-amyl- 2'-hydroxyphenyl) -benzotriazole, 2- (3 ', 5'-bis (a, α-dimethylbenzyl) -2'-hydroxyphenyl) -benzotriazole, a mixture of 2- (3'-1ert-buti1-2'- hydroxy-5 '- (2-octyloxycarbonylethyl) phenyl-5-chlorobenzotriazole, 2- (3'-tert-butyl-5' - [2- (2-ethylhexiloxy) -carbonylethyl] -2'-hydroxyphenyl) -5- chlorobenzotriazole, 2- (3'-tertbutyl-2'-hydroxy-5'- (2-methoxycarbonylethyl) phenyl) -5-chlorobenzotriazole, 2- (3'-tert-butyl-2'-hydroxy-5 '- (2 -methoxycarbonylethyl) phenyl) -benzotriazo lo, 2- (3'-tertbutyl-2'-hydroxy-5'- (2-octyloxycarbonylethyl) phenyl) -benzotriazole, 2- (3'-tert-butyl-5'- [2- (2-ethylhexyloxy) - carbonylethyl] -2'-hydroxyphenyl) -benzotriazole, 2- (3'-dodecyl-2'-hydroxy-5'-methylphenyl) -benzotriazole and 2- (3'-tert-butyl-2'-hydroxy-5'- (2-isooctyloxycarbonylethyl) -phenyl) -benzotriazole, 2, 2'-methylene-bis [4- (1,3,3-tetramethylbutyl) -6-benzotriazol-2-yl-phenol]; ester fication product of 2- [3'-tert-butyl -5'- (2-methoxycarbonylethyl) -2 '-hydroxyphenyl] -benzotriazole with polyethylene glycol 300; [R-CH2CH2-COO ((3⁄4) 3] 2- with R = 3'-tert-butyl-4'-hydroxy-5'-2H-benzotriazol-2-yl-phenyl.; 2. 2-hydroxybenzophenones , for example a 4-hydroxy-, 4-methoxy-, 4-octyloxy-, 4-decyloxy-, 4-dodecyloxy-, 4-benzyloxy-, 4,2 ', 4'-trihydroxy-, 2'-hydroxy- 4,4'-dimethoxy derivative.; 3. Esters of unsubstituted or substituted benzoic acids, for example 4-tert-butylphenylsalicylate, phenylsalicylate, octylphenylsalicylate, dibenzoylresorcinol, bis (4-tertbutylbenzoyl) resorcinol, benzoylresorcinol, 2,4-ditert 3,5-di-tert-butyl-4-hydroxybenzoic acid butylphenylester, 3,5-ditert-butyl-4-hydroxybenzoic acid hexadecyl ester, 3,5-di-tert-butyl-4 acid octadecyl ester -hydroxybenzoic, 2-methyl-4,6-ditert-butylphenyl ester of 3,5-di-tert-butyl-4-hydroxybenzoic acid.; 4. Acrylates, for example ethyl ester or isooctyl ester of α-cyano-β acid, β-diphenylacrylic, α-methoxycarbonylcinnamic acid methyl ester, α-cyanoβ-methyl-p-methoxycinnamic acid methyl ester or butyl ester ico, methyl ester of α-methosicarbonyl-p-methoxycinnamic acid and Ν- (βmetoxycarbonΙ-β-cyanovinyl) -2-methylindoline. ; 5. Steric hindered amines, e.g. bis [2, 2, 6, 6-tetramethylpiperidyl) sebacate, bis (2, 2, 6, 6-tetramethylpiperidyl) succinate, bis (1, 2, 2, 6, 6-pentamethylpiperidyl ) sebacate, bis (1,2,2,6,6-pentainetilpipe ridyl) ester of n-butyl-3, 5-di-tert-butyl-4-hydroxybenzylmalonic acid, the condensation product of 1-hydroxyethyl- 2, 2, 6, 6-tetramethyl-4-hydroxypiperidine and succinic acid, the condensation product of N, N'-bis (2,2,6, 6-tetramethyl-4-piperidyl) hexamethylenediamine and 4-tert-octylaminine -2,6-dichloro-1,3,5-s-triazine, tris (2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl ) -1,2, 3,4-butantetraoate, 1,1'- (1,2-ethanediyl) -bis (3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2, 2,6,6- tetramethylpiperidine, 4-stearyloxy-2, 2,6, 6-tetramethylpiperidine, bis (1,2,2,6,6-pentamethylpiperidyl) -2-n-butyl-2- (2-hydroxy-3,5-di- tert-butylbenzyl) maionate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro [4.5] decan-2,4-dione, bi s (1-octyloxy-2,2,6,6-tetramethylpiperidyl) -sebacate, bis (1-octyloxy-2,2,6,6-tetramethylpiperidyl) -su'ccinate, the condensation product of Ν, Ν'- bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, the condensation product of 2-chlor o-4, 6- di (4-nbutylanimino-2,2,6,6-tetramethylpiperidyl) -1,3,5-triazine and 1,2-bis (3-aminopropylamino) ethane, the condensation product of 2- chlor o-4, 6 -di (4-nbutylaminino- 1, 2, 2, 6, 6-pentamethylpiperidyl) -1, 3, 5-triazine and 1,2-bis (3-aminopropylamino) ethane, 8-acetyl-3-dodecyl-7, 7,9,9-tetramethyl-1,3,8-triazaspiro [4.5] decan-2,4-dione, 3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidyl) -pyrrolidin- 2,5-dione, 3-dodecyl-1- (1,2,2,6,6-pentamethyl-4-piperidyl) pyrrolidine-2, 5-dione. ; 6. Oxalic acid diammides, for example 4,4'-dioctyloxy-oxanilide, 2,2'-diethoxy-oxanilide, 2,2'-dioctyloxy-5,5'-di-tert-butyl-oxanilide, 2,2 ' -didodecyloxy-5,5'-di-tert-butyl-oxanilide, 2-ethoxy-2'-ethyloxanilide, Ν, Ν'-bis (3-dimethylaminopropyl) -oxalamide, 2-ethoxy-5-tert-butyl-2 '-ethyl-oxanilide and a mixture thereof with 2-ethoxy-2'-ethyl-5, 4'-ditert-butyl-oxanilide, mixtures of o- and pmethoxy-disubstituted oxanilides and mixtures of o- and pethoxy-disubstituted oxanilides. ; 7. 2- (2-hydroxyphenyl) -1,3, 5-triazine, e.g. 2,4,6-tris (2-hydroxy-4-octyloxyphenyl) -1, 3, 5-triazine, 2- (2-hydroxy- 4-octyloxyphenyl) -4, 6-bis (2, 4-dimethylphenyl) -1, 3, 5-triazine, 2- (2, 4-dihydroxyphenyl) -4, 6-bis (2, 4-dimethylphenyl) -1 , 3,5-triazine, 2, 4-bis (2-hydroxy-4-propyloxyphenyl) -6- (2, 4-dimethylphenyl) -1, 3, 5-triazine, 2- (2-hydroxy-4-octyloxyphenyl) ) -4, 6-bis (4-methylphenyl) -1, 3, 5-triazine, 2- (2-hydroxy-4-dodecyloxyphenyl) 4.6-bi s (2,4-dimethylphenyl) -1,3, 5- triazine, 2- [2-hydroxy-4- {2-hydroxy-3-butyloxy-propyloxy) phenyl] -4.6-bis (2,4-dimethylphenyl) -1,3, 5-triazine, 2- [2-hydroxy -4- (2-hydroxy-3-octyloxy-propyloxy) phenyl] -4.6-bis (2,4-dimethylphenyl) -1,3, 5-triazine and 2— [4— dodecyloxy / tridecylox -2-hydroxy-propyl ) oxy-2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine. ; 8. Phosphites and phosphonites, e.g. triphenylphosphite, diphenylalkylphosphites, phenyldyalkylphosphites, tris (nonylphenyl) -phosphite, trilaurylphosphite, trioctadecyl phyto, distearylpentaerythritol-diphosphate, trisold (2,4-di-di-tert-phosphite) -butylphenyl) pentaerythritolIdi phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritoliphosphite, bisisodecyloxypentaerythritol diphosphite, bis (2,4-ditert -butyl-6-methylphenyl) pentaerythritol phosphite, bis (2,4, 6-tris-tert-butylphenyl) pentaerythritoliphosphite, tristearylsorbitoltriphosphite, tetrakis (2,4-di-tertbutylphenyl) -4,4'-biphenylenediphosphonite, 6-isooctyloxy-2,4,8, 10-tetra-ter t-butyl-12H -dibenzo [d, g] -1,3,2-dioxaphosphocin, 6-fluoro-2, 4,8,10-tetra-tert-butyl-12-methyl-dibenzo [d, g] -1,3,2 -dioxaphosphocin, bis (2,4-di-tert-butyl-6-methylphenyl) methylphosphite, bis (2,4-ditert-butyl-6-methylphenyl) ethyl phosphite. . ; You can also use usual additives in the sector, such as, for example, creep control agents and agents that improve adhesion. To accelerate the photopolymerization, amines, such as, for example, triethanolamine, N-methyldiethanolamine, ethyl ester of p-dimethylaminobenzoic acid or Michler's ketone can be added as further additives (e). The action of the amines can be enhanced by adding aromatic ketones of the benzophenone type. Amines, which can be used as oxygen-capturing substances, are, for example, substituted N, N-dialkylanilines, as described in EP 339841. Further accelerating agents, co-initiators and auto-oxidants are thiols, thioethers, disulfides and phosphines , as described, for example, in EP 438123 and GB 2180358. It is also possible to add chain transport agents usual in the field to the compositions according to the invention. Examples are mercaptans, amines and benzothiazole. An acceleration of the photopolymerization can also be achieved by adding, as further additives (and), photosensitizing agents which displace or expand the spectral sensitivity. These include, in particular, aromatic carbonyl compounds, such as, for example, derivatives of benzophenone and thioxanthone, and, in particular, also isopropylthioxanthone, anthraquinone and derivatives of 3-acylcoumarin, terphenyls, styrylketones, and also 3- (aroylmethylene) thiazolines, camphorquinone, and also eosin, rhodamine and erythrosine dyes. For example, it is also possible to consider the amines mentioned above as photosensitizing agents. ; The hardening process, in particular in the case of pigmented compositions (for example compositions pigmented with titanium dioxide), can also be favored by adding as a further additive (e), a component that forms free radicals under thermal conditions, such as, for example, an azo compound, for example 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), a triazene, a diazosulfide or a pentazadiene, or a peroxy compound, such as a hydroperoxide or a peroxycarbonate, for example tert-butyl hydroperoxide, as described, for example, in EP 245639.; The compositions according to the invention can also contain, as further additives (e), a photoreducible dye, such as, for example, a dye of the xanthene type, benzoxanthene , benzothioxanthene, thiazine, pyronine, porphyrin or acridine, and / or a trihalomethyl compound which can be split by radiation. Similar substances are described, for example, in EP 445624.; Depending on the purpose for which the compositions are intended, further usual additives (e) are fillers, dyes, wetting agents and flow control agents. The addition of glass microspheres or pulverized glass fibers, as described, for example, in US 5013768, is suitable for the hardening of thick and pigmented coatings. ; The choice of additives (e) is governed by the sector of use in question and the desired properties for that sector. The additives (e) described above are usual for those skilled in the art and are used in the compositions according to the invention in the quantities which are usual in the art. The invention also relates to compositions which contain, as component (a), at least one ethylenically unsaturated photopolymerizable compound dissolved or emulsified in water. Such aqueous dispersions of radiation-curable prepolymers are commercially available in numerous variants and it must be understood that they are dispersions consisting of water and at least one prepolymer dispersed therein. The water concentration in such systems, for example, is between 5 and 80% by weight, in particular between 30 and 60% by weight. The prepolymer or the radiation curable prepolymer mixture are present in concentrations, for example, between 95 and 20%, in particular between 70 and 40% by weight. In such compositions, the sum of the percentages mentioned for the water and the prepolymer will be 100 in any case, the auxiliary substances and additives which are present in variable quantities according to the desired use, being in addition. The film-forming, radiation-curable prepolymers dispersed or often dissolved in water are mono-functional or poly-functional ethylenically unsaturated prepolymers, which can be initiated by free radicals, which prepolymers are per se known as aqueous dispersions of prepolymers, and contain, for example, from 0.01 to 1.0 moles of polymerizable double bonds per 100 g of prepolymer, and have an average molecular weight, for example, of at least 400, in particular between 500 and 10,000. However, prepolymers having higher molecular weights can also be considered, depending on the use for which they are intended. For example, there are polyesters containing polymerizable C-C double bonds which have a maximum acid number of 10, polyethers containing polymerizable C-C double bonds, reaction products containing hydroxyl groups of a polyepoxide that contains at least two epoxy groups per molecule, with at least one α.β-ethylenically unsaturated carboxylic acid, polyurethane (meth) acrylates and also acrylic copolymers containing a, β-ethylenically unsaturated acrylic radicals, as described in EP 12339. Blends of these prepolymers can also be used. Also suitable are the polymerizable prepolymers described in EP 33896, which are addition products with thioethers of polymerizable prepolymers, having an average molecular weight of at least 600, and a content in carboxylic groups between 0.2 and 15%, and containing 0 , 01 up to 0.8 moles of polymerizable C-C double bonds, per 100 g of prepolymer. Other suitable aqueous dispersions based on specific polymers of alkyl esters of (meth) acrylic acids are described in EP 41125, and suitable, radiation-curable, water-dispersible urethane-acrylate prepolymers can be found in DE 2936039. Such aqueous dispersions of prepolymers, curable by radiation, may contain, as further additives, dispersing agents, emulsifiers, antioxidants, photo-stabilizers, dyes, fillers, for example talc, gypsum, silicic acid, rutile, carbon black, zinc oxide, oxides of iron, reaction accelerators, flow agents, flow promoting agents, wetting agents, thickeners, matting agents, defoamers and other auxiliary substances common in surface coating technology. Suitable dispersing agents include water soluble high molecular weight organic compounds having polar groups, such as, for example, polyvinyl alcohols, polyvinylpyrrolidone and cellulose ethers. Non-ionic emulsifiers can be used as emulsifiers, but when appropriate, also ionic emulsifiers. In some cases, it may be advantageous to use mixtures of two or more photoinitiators of formulas I and II. Of course, it is also possible to use mixtures with further known photoinitiators, for example mixtures with further derivatives of benzophenone, with derivatives of acetophenone, dialkoxyacetophenones, α-hydroxy or α-amino-acetophenones, 4-aroyl-1,3-dioxolans, alkyl ethers of benzoin and benzyl ketals, such as, for example, benzyldimethyl ketal, phenylglyoxalates and their derivatives, phenylglyoxalates dimers, compounds of ferrocenium or titanocenes, such as, for example, dicyclopentadienyl-bis (2,6-difluoro-3-pyrrole-phenyl) -titanium, benzoylperoxides (suitable peroxides are described in US 4,950,581, column 19, lines 17-25) or complex salts of cyclopentadienylarene iron (II), for example (n <6> -iso-propylbenzene) (η <5> -cyclopentadienyl) iron ( II) hexafluorophosphate. When photoinitiators are used in hybrid systems, in addition to free radical hardening agents, cationic photoinitiators are used, such as, for example, aromatic salts of sulfonium, phosphonium or iodonium, as described, for example, in US 4950581, column 18, row 60 up to column 19, line 10.; The photopolymerizable compositions contain the photoinitiator or the mixtures of photoinitiators (b) advantageously in an amount comprised between 0.05 and 15% by weight, preferably in an amount comprised between 0.1 and 5% by weight, referring to the composition. The photoinitiator quantity indicated is the sum of all photoinitiators added when using their mixtures. Light-cured compositions can be used for various purposes, for example as printing inks, as clear lacquers, compositions for the white coating of surfaces, for example for wood or metals, as coating compositions. in the form of powder, as coating materials, inter alia, for paper, wood, metals or plastics, such as daylight hardenable paints for marking buildings and roads, as compounds for filling teeth, as adhesives, as pressure-sensitive adhesives, as laminating resins, in the manufacture of three-dimensional articles by mass curing (UV curing in transparent molds) or according to the stereolithography process, as described, for example, in US 4575330, in the manufacture of composite materials (e.g. polyester-styrene which, when appropriate, may contain glass fibers and / or other fibers and other auxiliary substances) and other thick-layer compositions, in the coating or sealing of electronic components or as coatings for optical fibers . The compositions according to the invention are also suitable for the manufacture of medical devices, auxiliary materials, for example contact lenses or implants. The compositions according to the invention can also be used in the preparation of gels having thermotropic properties, as described, for example, in DE 19700064 and EP 678534. The photoinitiators can be used as initiators for an emulsion polymerization, for a polymerization of beads or a suspension polymerization, as initiators of a polymerization step to fix orientation states in liquid crystalline monomers and oligomers or as initiators for fixing dyes on organic materials. Preferably, the compositions according to the invention are used in the preparation of surface coatings. The invention therefore also relates to a pigmented surface coating comprising a composition as described hereinabove, in particular a white pigmented composition, and relates to the use of a composition as described above as a coating or surface coating. , especially a white surface coating. In surface coatings, blends of a prepolymer with polyunsaturated monomers are often employed, which additionally contain a monounsaturated monomer. The choice of the prepolymer, in particular, determines the properties of the surface coating film, so that those skilled in the art are able to influence the properties of the cured film by varying the prepolymer. The polyunsaturated monomer functions as a crosslinking agent, which makes the surface coating film insoluble. The monounsaturated monomer functions as a reactive diluent, by means of which the viscosity is decreased, without having to use a solvent. Unsaturated polyester resins, in general, are used in two component systems, together with a monounsaturated monomer, preferably styrene. The compositions according to the invention can also be used as radiation curable powder coating compositions. The powder coating compositions can be used on solid resins and monomers which contain reactive double bonds, such as, for example, maleates, vinyl ethers, acrylates, acrylamides and mixtures thereof. The coating composition in the form of a free radical UV curable powder can be formulated by mixing unsaturated polyester resins with solid acrylamides (e.g. methylacrylate thymidoglycolate methyl ester) and a free radical photoinitiator, as described, for example, in the disclosure " Radiation Curing of Powder Coating ", Conference Proceedings, Radtech Europe 1993 by M. Wittig and Th. Gohmann. Similarly, free radical UV curable powder coating compositions can be formulated by mixing unsaturated polyester resins with solid acrylates, methacrylates or vinyl ethers and with a photoinitiator (or a mixture of photoinitiators). The powder coating compositions may also contain binding agents, as described, for example, in DE 4228514 and EP 636669. The UV curable powder coatings may also contain white or color pigments. For example, in particular titanium / rutile dioxide can be used in concentrations up to 50% by weight, obtaining a hardened powder coating composition, having a good hiding power. The process normally consists in applying the powder electrostatic or tribostatic to the substrate by spray, such as, for example, metal or wood, in melting the powder by heating and, after a uniform film has formed, in hardening by means of radiation the coating, with ultraviolet light and / or with visible light, for example using medium pressure mercury lamps, metal halide lamps or xenon lamps. A particular advantage of radiation curable powder coating compositions over the corresponding thermally curable compositions is that the flow time after the powder particles have been melted can be extended as desired in order to ensure the formation of a uniform, high gloss coating. Unlike thermally curable systems, radiation curable powder coating compositions can be formulated so that they melt at relatively low temperatures without the undesirable effect of shortening their useful life. For this reason, they are also suitable as coatings for thermo-sensitive substrates, such as, for example, wood or plastics. In addition to photoinitiators, powder coating formulations may also contain substances that absorb UV light. Suitable examples are listed above under points 1 to 8.; The photo-curable compositions according to the invention are suitable, for example, as coating materials for any type of substrate, for example wood, textiles, paper, products of ceramics, glass, plastics, such as polyesters, polyethylene terephthalate, polyolefins or cellulose acetate, in particular in the form of films, and also on metals, such as Al, Cu, Ni Fe, Zn, Mg or Co and GaAs, Si or S1O2, on which a protective layer must be applied. The substrates can be coated by applying a liquid composition, solution or suspension to the substrate. The choice of the solvent and its concentration are mainly regulated by the nature of the composition and the coating method. The solvent should be inert, i.e. it should not participate in any chemical reaction with the components and it should be possible to remove it again during drying following the coating operation. Suitable solvents include, for example, ketones, ethers and esters, such as methylethylketone, isobutylmethylketone, cyclopentanone, cyclohexanone, N-methylpyrrolidone, dioxane, tetrahydrofuran, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 1,2- dimethosgietane, ethyl acetate, n-butyl acetate and et yl-3-ethoxypropionate. The formulation is applied uniformly to a substrate by known coating methods, for example by spin coating, by dipping, by blade coating, by curtain coating, by brush application or by spraying, in particular by spraying. electrostatic and reverse roller coating, or by electrophoretic deposition. It is also possible to apply the photosensitive layer to a temporary flexible support and then coat the final substrate by transferring the layer by lamination. The applied quantity (thickness of the layer) and the nature of the substrate (support of the layer) depend on the desired sector of use. The range of thicknesses of the layer generally covers values between about 0.1 μm and a value greater than 100 μm, for example between 20 µm or 0.02 cm up to 10 cm, preferably between 0.02 cm and 2 cm. ; Light-curing is of considerable importance for printing inks (the compositions according to the invention can also be used in the preparation of such inks), since the drying time of the binding agent is a determining factor in the production speed of graphic products, and it should be on the order of fractions of a second. UV curable inks are especially important for screen printing. Another area of use for light-curing is the coating of metals, for example in the application of a finish to sheets and tubes, cans or bottle caps, and also as light-curing on plastic coatings, for example floor coverings. or walls based on PVC or in the application of a finish for automobiles. Examples of the light-curing of paper coatings include applying a finish to labels, disc wrappers or book covers. It is also interesting to use the compositions according to the invention in the manufacture of molding materials consisting of composite materials. The composite material consists of a self-supporting matrix material, for example woven glass fibers or, alternatively, for example vegetable fibers [see K.-P. Mieck, T. Reussmann in Kunststoffe 85 (1995), 366-370 or V. Narayanan, A.B. Scranton, Trends ih, Polymer Science 1997 (5), 12, 415], which is impregnated with the light-curing formulation. Composite molding articles which have been prepared using the compositions according to the invention have a high degree of mechanical stability and mechanical strength. The compositions according to the invention can also be used in molding, impregnating and coating materials, as described, for example, in EP 7086. Such materials are, for example, thin layer resins, on which there are high demands for what it relates to the hardening activity and resistance to yellowing and fiber-reinforced molding materials, such as, for example, flat or longitudinally or transversely corrugated luminous panels. Processes for the preparation of such molding materials, such as, for example, manual deposition processes, fiber spraying, spinning or winding processes, are described, for example, by P.H. Selden in "Glasfaserverstarkte Kunststoffe", p. 610, Springer Verlag Berlin-Heidelberg-New York 1967. Items that can be produced according to this process are, for example, boats, circuit boards or plywood, coated on both sides with glass fiber reinforced plastics, piping , sports equipment, roofing, containers, etc. Further examples of molding, impregnation and coating materials are thin layers of UP resin for molding materials containing glass fibers (GRP), for example corrugated and laminated panels of paper. The paper laminates can be based on urea or melamine resins. The thin layer is produced on a support (for example a sheet) before the production of the laminate. The photo-curable compositions according to the invention can also be used for pouring resins or for the insulating treatment of articles, for example electronic components, etc. The compositions can also be used to internally coat cavities and pipes. For the hardening process, medium pressure mercury lamps are used, as is usual in UV hardening, but lower intensity lamps, for example of the TL40W / 03 or TL40W / 05 type, are also particularly interesting. The intensity of these lamps roughly corresponds to that of sunlight. Direct sunlight can also be used for curing. A further advantage consists in the fact that the composite material can be removed from the light source in the plastic state, partially hardened and can be subjected to forming, after which by further exposure to light the complete hardening is effected. The photosensitivity of the compositions according to the invention is usually comprised between about 200 nm and about 600 nm (UV ray sector). Suitable radiation is present, for example, in sunlight or it can be light from artificial light sources. Therefore, a large number of the most varied types of light sources can be used. Both point sources and flat-shaped radiators (lamp mats} are suitable. Examples are carbon arc lamps, xenon arc lamps, medium pressure, high pressure and low pressure mercury arc radiators, doped, when it is appropriate, with metal halides (metal halide lamps), metal vapor lamps excited with microwaves, excimer lamps, superactinic fluorescent tubes, fluorescent lamps, incandescent argon lamps, flash lamps, photographic projectors, light emitting diodes (LED), electron beams and X-rays. The distance between the lamp and the substrate, according to the invention, to be exposed, can vary according to the desirable use and according to the type and intensity of the lamp, and the distance for example, between 2 cm and 150 cm. Laser light sources, for example excimer lasers, such as Krypton-F lasers for an exposure at 248 nm are particularly suitable. Lasers can also be used in the visible field. According to this method, plates for lithographic offset printing or plates for relief printing can be produced, for example. The photo-curable compositions according to the invention have surprisingly good full cure properties. The invention also relates to a method for the photopolymerization of monomeric compounds, oligomers or non-volatile polymers, which have at least one ethylenically unsaturated double bond, which method consists in irradiating a composition, as described above, with light in the range of 200 up to 600 nm. ; The invention also relates to the use of the compositions described above for the preparation of pigmented and non-pigmented surface coatings, printing inks, powder coatings, plates -, printing, adhesives, dental materials, composite materials, cable coatings of glass fibers and masks for screen printing, in the manufacture of three-dimensional objects by stereolithography; and concerns a procedure for the preparation of pigmented and non-pigmented surface coatings, printing inks, coatings in the form of powders, printing plates, adhesives, dental materials, composite materials, glass fiber cable coatings and screen printing masks, in the manufacture of three-dimensional objects by stereolithography. The invention further relates to the use of a composition according to claim 1, as a coating or surface coating, in particular a white surface coating, and as a screen printing ink, in particular a white screen printing ink. The invention likewise relates to a coated substrate which is coated on at least one surface with a composition described above and relates to cured compositions as such. The following examples further illustrate the invention. As in the remainder of the specification and in the patent claims, parts and percentages refer to weight, unless otherwise indicated. When alkyl or alkoxy radicals having more than 3 carbon atoms are mentioned, without reference to their isomeric form, the respective n-isomers are therefore meant. ; The following photoinitiators are used in the examples: P1 is a 1: 1 mixture of oxide of 2, 4, 6-trimethylbenzoyl-diphenyl-phosphine and 2-hydroxy-2-methyl-1-phenyl-propanone; P2 is oxide of 2,4,6-trimethylbenzoyl-diphenyl-phosphine; P3 is a 1: 1 mixture of oxide of (2,4,6-trimethylbenzoyl) -diphenyl-phosphine and of (1-hydroxycyclohexyl) -phenyl-ketone; P4 is a 1: 1 mixture of oxide of (2,4,6-trimethylbenzoyl) -ethoxy-phenyl-phosphine and of (1-hydroxycyclohexyl) -phenyl-ketone ;; P5 is a 1: 1 mixture of and of ;; (1 -hydroxycyclohexyl) -phenyl-ketone. ; The following optical brighteners are used in the examples: ;; of the Ciba Spezialitatenchemie ;;; wherein R15 - CH3 ;; wherein R15 = Example 1: Hardening of a white surface coating of epoxy-acrylate; A white surface coating is prepared having the following composition:; 65% of epoxy-acrylate (®EBECRYL 604, UCB, Belgium) 10% of hexandiol diacrylate ; 25% titanium dioxide (rutile type, ®RTC-2, Tioxide, France); 3% photoinitiator and 0.5% optical brightener (®UVITEX OB, Ciba Spezialitenchemie, Switzerland) are incorporated in the above formulation . Using a 150 μm slotted blade, layers are applied to a primed circuit board in a bright color. Exposure is carried out using two 80 W / cm medium pressure mercury lamps (UV-processor by AETEK, USA) at belt speeds of 10 m / minute and 20 m / minute respectively. After exposure, the pendulum hardness (PH) of the scratch-resistant and completely hardened layers in [s] according to Konig (DIN 53157) is determined and the yellowing indices are evaluated (ASTM D1925-88). The layer is considered to be completely hardened when the underside of the layer which is detached from the substrate after irradiation is dry. The higher the pendulum hardness value, the better the irradiated coating is hardened. The lower the value of the yellowing index (YI), the less yellow the irradiated layer is. The results are summarized in the following Table 1. Table 1 ;; ;; ®UVITEX OB from Ciba Spezzialetenchemie; Example 2: Hardening of a white polyester-acrylate surface coating; A white surface coating is prepared having the following composition:; 67.5% polyester-acrylate (®EBECRYL 830, UCB, Belgium) 5.0% hexandiol diacrylate; 2.5% trimethylolpropane triacrylate; 25.0% titanium dioxide (rutile type ®RTC-2,; Tioxide, France); Application, curing and measurements are performed as described in Example 1. The photoinitiators and optical brighteners used and the measurement results are listed in Table 2.; Table 2 ;; ;; Example 3: Hardening of a white polyester-acrylate surface coating; A white surface coating is prepared having the composition described in Example 2. Application and hardening are carried out as described in Example 1. In each case, after hardening, determine the yellowing index and the pendulum hardness at a conveyor speed of 5 m / minute. However, in addition to the yellowing index and the pendulum hardness, the maximum depth of the indurable free layer (FL) is evaluated. For this purpose, a drop of the formulation to be cured is applied to a substrate and irradiated with a conveyor speed of 3 m / minute. The hardened layer is then detached from the substrate and the thickness (in μm) of the hardened layer is evaluated. The thicker the layer, the better the complete hardening of the formulation under examination. In addition, the number of tests at a speed of 10 m / minute required to obtain a touch-dry hardened layer (referred to as tests n x 10 m / minute) is evaluated. The photoinitiators and optical brighteners used and the measurement results are listed in Table 3.; Table 3 ;; ;; * value not determinable

®UVITEX OB from Ciba Spezialitenchemie

Example 4: Hardening of a white polyester-acrylate surface coating

A white surface coating is prepared having the composition described in Example 2. The initiator P3 is used as the photoinitiator. The application and hardening are carried out as described in Example 1. In each case the pendulum hardness after hardening is determined with a conveyor speed of 3 m / minute. In addition to the pendulum hardness, the depth of the maximum hardenable free layer (FL) is measured as described in Example 3. The optical brighteners used and the measurement results are listed in Table 4.

Table 4

PH Y1 rinse aid

optical [s] [μm]

(0.5%)

®UVITEX OB 123 110

A1 116 105

A2 128 106

Claims (16)

CLAIMS 1. Photopolymerizable composition which contains (a) at least one ethylenically unsaturated photopolymerizable compound and (b) as photoinitiator, at least one compound of a mono-, bis- or tris-acylphosphine oxide or a mixture of such a compound or compounds with a compound of an α-hydroxyketone, an α-aminoketone and / or a derivative of benzoin, (c) at least one optical brightener e (d) at least one pigment. 2. Composition according to claim 1, wherein the compound consisting of mono-bis or tris-acylphosphine oxide is a compound of formula I wherein R1 and R2, each independently, are C1-C18alkyl; C2-C18alkyl interrupted with one or more non-consecutive oxygen atoms; C1- C4 phenyl-substituted alkyl; C2-C8alkenyl, phenyl, naphthyl, biphenyl or C5-C12 Cycloalkyl, the phenyl, naphthyl, biphenyl and C5-C12cycloalkyl radicals being unsubstituted or mono- to penta-substituted with halogen, C1- C8alkyl, C1- C8alkylthio and / or with C1-C8alkoxy, or R1 and R2 are -COR3; R3 is phenyl which is unsubstituted or is mono- to penta-substituted with C1-C12alkyl, C1-C12alkoxy, C1-C12alkylthio and / or with halogen. 3. Composition according to claim 1, wherein the compound consisting of α-hydroxyketone, α-aminoketone or the benzoin derivative is a compound of formula II in which R4 is hydrogen, C1-C18alkyl, C1 -C18allkoxy, --OCH2CH2-OR8, morpholino, SCH3, a group or a group n has a value between 2 and 10; G is the radical R5 is hydroxy, C1-C16alkoxy, morpholino, dimethylaminino or -O (CH2CH2O) m-C1-C16alkyl; R6 and R7, each independently, are hydrogen, C1-C6alkyl, phenyl, benzyl, C1-C6alkoxy or -O (CH2CH2O) m-C1-C16alkyl, or R6 and R7, together with the carbon atom to which they are bonded, they form a cyclohexyl ring; m is a number between 1 and 20; wherein R5, R6 and R7 are not all C1-C16alkoxy or -O {CH2CH2O) m-C1-C16alkyl at the same time; And R8 is hydrogen, or 4. Composition according to claim 1, wherein in the compounds of formula I R1 and R2, each independently, are C1-C18alkyl; C2C18alkyl interrupted with one or more non-consecutive oxygen atoms; C1-C4 phenyl-substituted alkyl; C2-C8alkenyl, phenyl, naphthyl, diphenyl or C5-C12cycloalkyl, the phenyl, naphthyl, diphenyl and C5-C12Cycloalkyl radicals being unsubstituted or mono- to penta-substituted with halogen, C1-C8alkyl, C1-C8alkylthio and / or with C1-C8alkoxy; and R3 is phenyl which is unsubstituted or is mono- to penta-substituted with C1-Cì2alkyl, C1-C12alkoxy, C1-C12alkylthio and / or with halogen. 5. Composition according to claim 1, wherein, in the compounds of formula I, R1 and R2, each independently, are C1-C18alkyl, or phenyl which is unsubstituted or is mono- to pentasubstituted with halogen, C1-C8alkyl, C1-C8alkylthio and / or with C1-C8alkoxy. 6. Composition according to claim 1, wherein, in the compounds of formula I, R3 is phenyl which is di-substituted or tri-substituted with C1-C12alkyl or with C1-C12alkoxy. 7. Composition according to claim 1, wherein, in the compounds of formula II R4 is hydrogen, -OCH2CH2-OR8, morpholino or SCH3; R5 is hydroxy, C1-C16alkoxy, morpholino or dimethylamino; R6 and R7, each independently, are C1-C6alkyl, benzyl or C1-C16alkoxy, or R6 and R7, together with the carbon atom to which they are bonded, form a cyclohexyl ring; however in which R5, R6 and R7 are not all at the same time C1-Ciealcossi; And Ra is hydrogen. 8. Composition according to claim 1, wherein the pigment (d) is a white pigment, in particular titanium dioxide. 9. Composition according to claim 1, wherein the optical brightener (c) is a compound selected from the group consisting of pyrazolines, stilbenes, triazines, thiazoles, benzoxazoles, xanthones, triazoles, oxazoles, thiophene and coumarins. 10. Composition according to claim 1, wherein component (c) is a compound of formula III wherein X is a group or R9, R10, R11 and R12, each independently, are hydrogen, C1-C8alkyl; C1-C8alkyl substituted with -COO- C1-C8alkyl; -COO-C1-C20alkyl or a, α-dimethylbenzyl. 11. Composition according to claim 1, which contains as component (b) a compound of formula I, in which R1 and R2 are phenyl and R3 is C1-C4alkyl-substituted phenyl or which contains as component (b) a mixture of a compound of formula I, in which R1 and R2 are phenyl and R3 is C1-C4alkyl-substituted phenyl and of a compound of formula II, in which R4 is hydrogen, R5 is hydroxy and R6 and R7 are each C1-C4alkyl or together they form a cyclohexyl ring; which contains as component (c) a compound of formula III, in which X is a radical, R10 and R12 are hydrogen and R9 and R11 are each tert-butyl; and which contains as component (d) a titanium dioxide pigment. 12. Pigmented surface coating comprising a composition according to claim 1. 13. Use of a composition according to claim 1, as a coating or surface coating, in particular as a white surface coating, and as a screen printing ink, in particular a white screen printing ink. 14. Process of photopolymerization of monomeric compounds, oligomers or non-volatile polymers having at least one ethylenically unsaturated double bond, which consists in irradiating a composition according to claim 1, with a light having a wavelength between 200 and 600 nm . 15. A coated substrate which is coated on at least one surface with a composition according to claim 1. 16. A cured composition according to claim 1.