Chromophore-functionalized polyols

Abstract

A polyol having at least one chromophore moiety is provided. The polyols are used to prepare photocurable compositions that do not require additional individual chromophores.

Description

TECHNICAL FIELD

[0001] Provided are polyols having at least one chromophore moiety. The polyols are used to make photocurable compositions that do not require additional separate chromophores. BACKGROUND

[0002] In photo- or other actinic radiation-curable systems, including those containing urethane (meth)acrylates, the free radicals that initiate curing are produced by the photolysis of a photoinitiator molecule. A variety of such small molecule photoinitiators are commercially available and well known to those skilled in the art. A disadvantage of using small molecule photoinitiators is that small molecule photofragments inevitably remain in the cured composition. This is true whether fragmentation photoinitiators (Norrish Type I) or hydrogen abstraction bimolecular photoinitiators (Norrish Type II) are used. Small molecule fragments are often the source of undesirable odors, volatile organic content, and extractable / leachable molecules.

[0003] WO 2010 / 124950 A1 and JP 2017-125033 A disclose polymeric thioxanthones.

[0004] The use of oligomeric / polymeric photoinitiators is not an ideal solution as tradeoffs typically include reduced cure speed, limited resin compatibility, and increased formulation cost due to the reduced active content of the polymeric photoinitiating system. In some cases, polymeric photoinitiators can also adversely affect the properties of the cured material due to the unoptimized nature of the initiator polymer backbone for any given application. Thus, a useful monomeric photoinitiator that can be reacted into the backbone during the light initiated reaction to form a polymer would be useful.

[0005] The present inventors have prepared unique photoinitiators having at least two hydroxyl groups that are capable of reacting with other monomers, such as polyisocyanates, to form polymers having a photoinitiator moiety in the backbone of the polymer. Thus, photopolymerizable compositions containing these photoinitiators can not require additional photoinitiators. Since the chromophore-containing material is contained in the final polymer, there is no risk of photoinitiator leaching or evaporating from the final polymer, thereby resulting in undesirable volatile organic content. Another advantage is that photopolymerizable compositions including these monomers and related oligomers containing these monomers, the chromophore / photoinitiator is by definition bound and compatible with the oligomer, and thus the risk of phase separation or changes in the mechanical properties of the cured material due to the oligomeric photoinitiator component is minimized. SUMMARY

[0006] The present invention relates to a photoinitiator according to the following formula (I):

[0007]

[0008] wherein n1, n2, Q, X, Y, Z, R 1 , R 2 , R 3 and R 4 are as defined herein.

[0009] The present invention further relates to a process for the preparation of a photoinitiator by reacting a component a) bearing a chromophore with a polyepoxide component b), wherein component a) comprises at least one compound bearing at least one chromophore moiety and at least one epoxide reactive group, and, component b) comprises at least one compound bearing at least two epoxide rings.

[0010] The present invention further relates to the use of a photoinitiator according to the present invention as photoinitiating system in a radiation-curable composition.

[0011] The present invention further relates to the use of a photoinitiator according to the present invention in a photopolymerization reaction.

[0012] The present invention further relates to the use of a photoinitiator according to the present invention for obtaining a photoreactive oligomer, in particular a photoreactive urethane oligomer, more particularly a photoreactive urethane (meth)acrylate oligomer. DETAILED DESCRIPTION

[0013] Definitions

[0014] In this application, the term "comprising" means "including, comprising, or consisting of" and the inclusion not only of the listed items but also of equivalents thereof.

[0015] Unless otherwise indicated, weight % in a compound or composition is based on the weight of the compound or composition, respectively.

[0016] Unless otherwise indicated, molecular weight herein is number average molecular weight measured using gel permeation chromatography with polystyrene standards.

[0017] As used herein, the term "independently selected" in reference to the selection of a group in a structure means that if there is more than one group in the structure, they do not all have to be the same, so long as they are selected from the list of choices. For example, the statement "R 3 may be independently selected from a direct bond or a linking group" means that one R 3 may be a direct bond and the other may be, for example, a linking group.

[0018] According to some embodiments, R a groups can all be the same. According to some embodiments, R a groups can all be the same. According to some embodiments, R 3 groups can all be the same. According to some embodiments, R 4 groups can all be the same. According to some embodiments, X groups in the structure can all be the same. According to some embodiments, Y groups in the structure can all be the same. According to some embodiments, Z groups in the structure can all be the same. According to some embodiments, Q groups in the structure can all be the same.

[0019] A "chromophore moiety" refers to a moiety that contains a group that is capable of absorbing light and generating a reactive species that can be used to initiate a polymerization reaction. In particular, a chromophore moiety can be a Norrish Type II chromophore moiety, i.e., a chromophore moiety that does not fragment upon exposure to radiation and thus will not typically initiate free radical chain polymerization unless a co-initiator such as an amine synergist is present. Upon exposure to radiation, interaction between the Type II chromophore moiety and the co-initiator results in the generation of a free radical species that can initiate polymerization of a UV-curable resin.

[0020] As used herein, "equivalents" refers to the number of moles of a particular reactant needed to react with all of the moles of another reactant that can have a different number of reactive groups. For example, when reacting the hydroxyl group of a monohydric alcohol with the epoxy group of a triepoxide, three moles or three "equivalents" of the monohydric alcohol are needed to react completely with one mole of the triepoxide.

[0021] As used herein, the term "glycidyl ether group" refers to a group of the following formula (3):

[0022] .

[0023] As used herein, the term "glycidyl ester group" refers to a group of the following formula (4):

[0024] .

[0025] As used herein, the term "glycidyl amine group" refers to a group of the following formula (5):

[0026]

[0027] wherein R 6 is H, alkyl, aryl, or a glycidyl group of the formula .

[0028] As used herein, the term "glycidyl amide group" refers to a group of the following formula (6):

[0029]

[0030] wherein R 7 is H, alkyl, aryl, or a glycidyl group of the formula .

[0031] As used herein, the term "cycloaliphatic epoxide group" refers to a group of the following formula (7):

[0032] .

[0033] As used herein, the term "epoxidized oxirane group derived from a non-cyclic carbon-carbon double bond" refers to a group of the following formula (8):

[0034]

[0035] wherein R 4 is H, optionally substituted alkyl or optionally substituted alkenyl, and

[0036] The epoxide ring is not directly attached to a group of the formula -CH2-O-, -CH2-O-C(=O)-, -CH2-NR 7 - or -CH2-NR 7 -C(=O)-, wherein the symbol represents the point of attachment to the epoxide ring (i.e., the epoxide ring is not included in the glycidyl ether group, glycidyl ester group, glycidyl amine group, glycidyl amide group, or cycloaliphatic epoxide).

[0037] The term "C1-C6" refers to the number of carbon atoms included in a particular group or linking group. For example, a C1-C6alkylene is an alkylene group comprising 1 to 6 carbon atoms.

[0038] The term "alkyl" refers to a monovalent saturated acyclic hydrocarbon group of the formula -C n H 2n+1 wherein n is 1 to 20. Alkyl groups can be linear or branched. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, 2-methylbutyl, 2,2-dimethylpropyl, n-hexyl, 2-methylpentyl, 2,2-dimethylbutyl, n-heptyl, 2-ethylhexyl, and the like.

[0039] The term "heteroatom-containing alkyl" refers to an alkyl group comprising one or more heteroatoms independently selected from O, N, or S.

[0040] The term "cycloalkyl" refers to a monovalent saturated hydrocarbon group comprising a ring. Examples of cycloalkyl groups include cyclopentyl, cyclohexyl, and isobornyl.

[0041] The term "heterocycloalkyl" refers to a cycloalkyl group having at least one ring atom that is a heteroatom selected from O, N, or S.

[0042] The term "alkenyl" refers to a monovalent univalent unsaturated hydrocarbon group comprising at least one carbon-carbon double bond. Alkenyl groups can be linear or branched.

[0043] The term "alkynyl" refers to a monovalent univalent unsaturated hydrocarbon group comprising at least one carbon-carbon triple bond. Alkynyl groups can be linear or branched.

[0044] The term "aryl" refers to an optionally substituted polyunsaturated aromatic group. Aryl groups can contain a single ring (i.e., phenyl) or more than one ring wherein at least one ring is aromatic. When an aryl group contains more than one ring, the rings can be fused, joined via a covalent bond (e.g., biphenyl), or a combination thereof. The aromatic ring(s) can optionally contain one to two additional fused rings (i.e., cycloalkyl, heterocycloalkyl, or heteroaryl). The term "aryl" also encompasses partially hydrogenated derivatives of carbocyclic ring systems as described above. Examples include phenyl, naphthyl, biphenyl, phenanthryl, and naphthacenyl.

[0045] The term "heteroaryl" refers to an aryl group having at least one ring atom that is a heteroatom selected from O, N, or S.

[0046] The term "aralkyl" refers to an aryl group substituted with an alkyl group. An example of an aralkyl group is tolyl.

[0047] The term "alkaryl" refers to an alkyl group substituted with an aryl group. An example of an alkaryl group is benzyl (-CH2-phenyl).

[0048] The term "halogen" refers to an atom selected from Cl, Br, F, and I.

[0049] The term "alkoxy" refers to a group of the formula -O-alkyl, wherein alkyl is as defined above.

[0050] The term "aryloxy" refers to a group of the formula -O-aryl, wherein aryl is as defined above.

[0051] The term "thioalkyl" refers to a group of the formula -S-alkyl, wherein alkyl is as defined above.

[0052] The term "thioaryl" refers to a group of the formula -S-aryl, wherein aryl is as defined above.

[0053] The term "araneoxy" refers to a group of the formula -O-aranealkyl, wherein the aranealkyl group is as defined above.

[0054] The term "alkylaryloxy" refers to a group of the formula -O-alkylaryloxy, wherein the alkylaryl group is as defined above.

[0055] The term "alkylene" refers to a compound derived from C16. m H 2m+2 (where m is 1 to 50) is a polyvalent linker of an alkane (by removing a hydrogen atom at each linker site). Alkylenes can be divalent, trivalent, tetravalent, or have even higher valences.

[0056] The term "alkenyl" refers to a multivalent aliphatic linker containing at least one carbon-carbon double bond.

[0057] The term "heteroatom-containing alkylene" refers to an alkylene containing one or more heteroatoms independently selected from O, N, or S.

[0058] The term "heteroatom-containing subalkenyl" refers to a subalkenyl that contains one or more heteroatoms independently selected from O, N, or S.

[0059] The term "cycloalkylene" refers to a multivalent linker containing a non-aromatic ring. Examples of cycloalkylenes include cyclopentylene, cyclohexylene, and cyclohexyldimethylene (i.e., -CH2-Cy-CH2, where Cy is cyclohexylene).

[0060] The term "heterocyclic alkyl" refers to a multivalent linker containing a non-aromatic ring having at least one ring atom, which is a heteroatom selected from O, N, or S.

[0061] The term "triaryl" refers to a multivalent linker containing at least one aromatic ring.

[0062] The term "heteroaryl" refers to a multivalent linker containing an aromatic ring having at least one ring atom, which is a heteroatom selected from O, N, or S.

[0063] The term "alkylamino" refers to an alkyl group that is substituted with at least one amino group.

[0064] The term "alkyl thiol" refers to an alkyl group that has been substituted with at least one thiol group.

[0065] The term "hydroxyalkyl" refers to an alkyl group that is substituted with at least one hydroxyl group.

[0066] The term "halogenated alkyl" refers to an alkyl group that has been substituted with at least one halogen.

[0067] The term "perfluoroalkyl" refers to an alkyl group in which all hydrogen atoms are replaced by fluorine atoms.

[0068] The term "linker" refers to a polyvalent group comprising at least one carbon atom and / or at least one heteroatom (e.g. O, N or S). A linker can link together at least two moieties of a compound, in particular 2 to 4 moieties of a compound. For example, a linker linking together two moieties of a compound is referred to as a bivalent linker, a linker linking together three moieties of a compound is referred to as a trivalent linker, etc...

[0069] The term "aliphatic compound, group or linker" refers to a compound, group or linker which is non-aromatic. The term aliphatic compound, group or linker encompasses a compound, group or linker comprising a non-aromatic ring (i.e. a cycloaliphatic ring). It can be linear or branched, saturated or unsaturated, cyclic or acyclic. It can be substituted by one or more groups, for example selected from alkyl, hydroxyl, halogen (Br, CI, I), isocyanate, carbonyl (=0), amine, carboxylic acid, -C(=0)-OR', -C(=0)-0-C(=0)-R', each R' being independently a C1-C6 alkyl group. It can comprise one or more bonds selected from ether, ester, amide, urethane, urea, carbonate, organosiloxane, and mixtures thereof.

[0070] The term "aromatic compound, group or linker" refers to a compound, group or linker comprising at least one aromatic ring (i.e. a ring obeying H ckel’s aromaticity rule), in particular one, two or three (preferably one or two) aromatic rings. The term aromatic compound, group or linker encompasses an araliphatic compound, group or linker (i.e. comprising both an aromatic and a non-aromatic moiety). It can be substituted by one or more groups as defined for the term "aliphatic compound, group or linker". It can comprise one or more bonds as defined for the term "aliphatic compound, group or linker".

[0071] The term "acyclic compound, group or linker" refers to a compound, group or linker which does not comprise any ring.

[0072] The term "cyclic compound, group or linker" refers to a compound, group or linker comprising at least one aromatic or non-aromatic ring.

[0073] The term "saturated compound, group or linker" refers to a compound, group or linker which does not comprise any carbon-carbon double or triple bond.

[0074] The term "unsaturated compound, group or linker" refers to a compound, group or linker comprising one or more carbon-carbon double or triple bonds, in particular one or more carbon-carbon double bonds.

[0075] The term "polyol" refers to a compound comprising at least two hydroxyl groups.

[0076] The term "residue of a polyol" as used herein refers to a moiety obtained by removing a hydroxyl group of a polyol.

[0077] The term "polyacid" as used herein refers to a compound bearing at least two carboxylic acid groups.

[0078] The term "residue of a polyacid" as used herein refers to a moiety obtained by removing a carboxylic acid group of a polyacid.

[0079] The term "polyamine" as used herein refers to a compound bearing at least two primary and / or secondary amino groups.

[0080] The term "residue of a polyamine" as used herein refers to a moiety obtained by removing a primary and / or secondary amino group of a polyamine.

[0081] The term "hydroxy-acid" as used herein refers to a compound bearing at least one hydroxyl group and at least one carboxylic acid group.

[0082] The term "residue of a hydroxy-acid" as used herein refers to a moiety obtained by removing a hydroxyl group and a carboxylic acid group of a hydroxy-acid.

[0083] The term "hydroxy-amine" as used herein refers to a compound bearing at least one hydroxyl group and at least one primary and / or secondary amino group.

[0084] The term "residue of a hydroxy-amine" as used herein refers to a moiety obtained by removing a hydroxyl group and a primary and / or secondary amino group of a hydroxy-amine.

[0085] The term "hydroxyl" refers to an -OH group.

[0086] The term "amino" refers to an -NR a1 R b1 group, wherein R a1 and R b1 are independently H or an optionally substituted alkyl group. A "primary amino group" refers to an -NR a1 R b1 group, wherein R a1 and R b1 are H. A "secondary amino group" refers to an -NR a1 R b1 group, wherein Ra1 H and R b1 is an optionally substituted alkyl group.

[0087] The term "carboxylic acid group" refers to a -COOH group.

[0088] The term "isocyanate group" refers to a -N=C=O group.

[0089] The term "direct bond" refers to a covalent bond.

[0090] The term "ester bond" refers to a -C(=0)-0- or -0-C(=0)- bond.

[0091] The term "ether bond" refers to a -0- bond.

[0092] The term "silicone oxide bond" refers to a -Si(R c1 )2-0- bond, wherein R c1 is an organic group, in particular an organic group selected from alkyl, alkoxy and aryl.

[0093] The term "carbonate bond" refers to a -0-C(=0)-0- bond.

[0094] The term "carbamate or urethane bond" refers to a -NH-C(=0)-0- or -0-C(=0)-NH- bond.

[0095] The term "carbamate oligomer" refers to an oligomer comprising at least two carbamate bonds.

[0096] The term "polyisocyanate" refers to a compound comprising at least two isocyanate groups.

[0097] The term "optionally substituted compound, group or linker" refers to a compound, group or linker which is optionally substituted with one or more groups selected from halogen, alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkoxy, aryloxy, aralkyl, alkaryl, aralkyloxy, alkaryloxy, haloalkyl, -OH, -SH, hydroxyalkyl, thioalkyl, thioaryl, alkylthiol, amino, alkylamino, isocyanate, nitrile, oxo (=0), -C(=0)-R', -0-C(=0)-R', -C(=0)-OR', -C(=0)-N(R')2, -NR'-C(=0)-R', -C(=0)-0-C(=0)-R' and -S02-N(R')2, each R' being independently H or an optionally substituted group selected from alkyl, aryl and alkaryl.

[0098] Photoinitiators of formula (I)

[0099] The photoinitiator of the present application corresponds to the following formula (I):

[0100]

[0101] wherein

[0102] n1 is 0, 1, 2, 3, or 4;

[0103] n2 is 0, 1, 2, 3, or 4;

[0104] the sum of n1 + n2 is equal to 1, 2, 3, or 4;

[0105] each Q is independently a chromophore moiety;

[0106] each X is independently -NR 1 -, -O-, -S-, -C(=O)-O- or -C(=O)-NR 1 -;

[0107] each Y is independently a direct bond, -O-CH2-, -C(=O)-O-CH2-, -NR 5 -CH2- or -C(=O)-NR 5 -CH2-;

[0108] each Z is independently a direct bond, -CH2-O-C(=O))- or -C(=O)-O- ;

[0109] each R 1 is independently H, alkyl, or aryl;

[0110] R 2 is a direct bond or a linker;

[0111] each R 3 is independently a direct bond or a linker;

[0112] each R 4 is independently H, optionally substituted alkyl, or optionally substituted alkenyl;

[0113] each R 5 is independently H, alkyl, aryl, or -CH2-CH(OH)-CH2-X-R 3 -Q, wherein Q, X and R 3 are as defined above;

[0114] the symbol 3 represents the point of attachment to R ;

[0115] symbol denotes the point of attachment to R 2 .

[0116] In formula (I), n1 has a value of 0, 1, 2, 3 or 4. In particular, n1 can have a value of 0, 1 or 2, more particularly n1 can be 0.

[0117] In formula (I), n2 has a value of 0, 1, 2, 3 or 4. In particular, n2 can have a value of 2, 3 or 4, more particularly n2 can be 2 or 3.

[0118] In formula (I), the sum of n1 + n2 is equal to 1, 2, 3 or 4. In particular, the sum of n1 + n2 can be equal to 2, 3 or 4, more particularly the sum of n1 + n2 can be equal to 2 or 3. If the sum of n1 + n2 is equal to 1, n1 is preferably 0 and n2 is preferably 1, Y is preferably -NR 5 -CH2- or -C(=O)-NR 5 -CH2- and R 5 is preferably -CH2-CH(OH)-CH2-X-R 3 -Q.

[0119] In one embodiment, n1 can have a value of 0 and n2 can have a value of 1, 2, 3 or 4. In particular, n1 can have a value of 0 and n2 can have a value of 2 or 3. In another embodiment, n2 can have a value of 0 and n1 can have a value of 2, 3 or 4. In particular, n2 can have a value of 0 and n1 can have a value of 2. In another embodiment, n1 can have a value of 1, 2 or 3 and n2 can have a value of 1, 2 or 3. In particular, n1 can have a value of 1 and n2 can have a value of 1 or 2.

[0120] In a preferred embodiment, n2 is not 0 and R 2 carrying at least one moiety corresponding to the following formula (1):

[0121]

[0122] wherein Q, X, Y, R 3 and R 4 are as defined herein.

[0123] R 2 may carry at least one moiety of formula (1) wherein Y is -O-CH2- and R 4 is H. Such moieties can be derived from the ring opening of a glycidyl ether group.

[0124] R2 may bear at least one moiety of formula (1) wherein Y is -(C=0)-0-CH2- and R 4 is H. Such moieties can be derived from the ring opening of a glycidyl ester group.

[0125] R 2 may bear at least one moiety of formula (1) wherein Y is -NR 5 -CH2-, R 4 is H and R 5 is as defined above. Such moieties can be derived from the ring opening of a glycidyl amine group.

[0126] R 2 may bear at least one moiety of formula (1) wherein Y is -(C=0)-NR 5 -CH2-, R 4 is H and R 5 is as defined above. Such moieties can be derived from the ring opening of a glycidyl amide group.

[0127] R 2 may bear at least one moiety of formula (1) wherein Y is a direct bond and R 4 is H, optionally substituted alkyl or optionally substituted alkenyl. Such moieties can be derived from the ring opening of an epoxy group derived from the epoxidation of an acyclic carbon-carbon double bond.

[0128] R 2 may bear 1, 2, 3 or 4 or four moieties of formula (1). Such moieties can be the same or different from each other. For example, R 2 may bear 2, 3 or 4 moieties of formula (1) wherein Y is -O-CH2- and R 4 is H. Alternatively, R 2 may bear 2, 3 or 4 moieties of formula (1) wherein Y is -(C=0)-0-CH2- and R 4 is H. Alternatively, R 2 may bear 1 or 2 moieties of formula (1) wherein Y is -NR 5 -CH2- and R 4 is H. Alternatively, R 2 may bear 1 or 2 moieties of formula (1) wherein Y is -(C=0)-NR 5 -CH2- and R 4 is H. Alternatively, R 2may carry two or three moieties of formula (1) wherein Y is a direct bond and R 4 is H or optionally substituted alkyl. Alternatively, R 2 may carry at least two moieties of formula (1) wherein the moieties differ from each other due to the nature of Y and / or R 4 .

[0129] In another embodiment, n1 is not 0 and R 2 carries at least one moiety according to formula (2):

[0130]

[0131] wherein Q, X, Z and R 3 are as defined herein.

[0132] Such moieties can be derived from the ring opening of a cycloaliphatic epoxide group.

[0133] R 2 may carry at least one moiety of formula (2) wherein Z is -CH2-O-C(=O))- .

[0134] R 2 may carry at least one moiety of formula (2) wherein Z is -C(=O)-O- .

[0135] R 2 may carry at least one moiety of formula (2) wherein Z is a direct bond.

[0136] R 2 may carry 2, 3 or 4 or four moieties of formula (2). Such moieties can be identical or different from each other. For example, R 2 may carry 2, 3 or 4 moieties of formula (2) wherein Z is -CH2-O-C(=O))- . Alternatively, R 2 may carry 2, 3 or 4 moieties of formula (2) wherein Z is -C(=O)-O- . Alternatively, R 2 may carry at least two moieties of formula (2) wherein the moieties differ from each other due to the nature of Z.

[0137] In yet another embodiment, n1 and n2 are both not 0, and R 2 carries at least one moiety according to formula (1) and at least one moiety according to formula (2). In particular, R 2 may carry 1 moiety according to formula (1) wherein Y is a direct bond and R 4is H) and one moiety of formula (2) wherein Z is a direct bond. Alternatively, R 2 may carry 1 moiety according to formula (1) wherein Y is -O-CH2- and R 4 is H) and one moiety of formula (2) wherein Z is a direct bond. Alternatively, R 2 may carry 2 moieties according to formula (1) wherein Y is -(C=0)-0-CH2- and R 4 is H) and one moiety of formula (2) wherein Z is a direct bond.

[0138] The photoinitiators of formula (I) can correspond to one of the following formulae (I-a) to (I-n):

[0139]

[0140]

[0141]

[0142] wherein

[0143] Q, X, R 2 , R 3 , R 4 and R 5 as defined herein;

[0144] n3, n4, n7, n 14 and n 15 are independently 2, 3 or 4, preferably 2 or 3;

[0145] n5 and n6 are independently 1 or 2, preferably 2;

[0146] n8 is 1, 2 or 3, preferably 2;

[0147] n9 is 1, 2 or 3, preferably 1;

[0148] n 10 , n 11 , n 16 , n 17 , n 18 , n 19 , n 20 , n 21 , n 22 and n 23 are independently 1 or 2, preferably 1;

[0149] n 12 and n 13 are independently 1, 2 or 3, preferably 1.

[0150] Preferred are photoinitiators of formula (I-a), (I-b), (I-c), (I-e), (I-f), (I-g) and (I-h). Particularly preferred are photoinitiators of formula (I-a), (I-b), (I-c) and (I-e). More particularly preferred are photoinitiators of formula (I-a).

[0151] The photoinitiators of formula (I) and (I-a) to (I-n) comprise at least one, preferably at least two chromophore moieties Q. In particular, the photoinitiators of formula (I) and (I-a) to (I-n) comprise 2, 3 or 4 chromophore moieties Q.

[0152] Each chromophore moiety Q can independently comprise a benzophenone moiety, a thioxanthone moiety, an anthraquinone moiety, a xanthone moiety or an acridinone moiety.

[0153] In particular, each chromophore moiety Q can independently be a benzophenone moiety according to the following formula (A) or a thioxanthone, anthraquinone, xanthone or acridinone moiety according to the following formula (B):

[0154]

[0155] wherein

[0156] E is S, O, C(=O) or NR, in particular S;

[0157] R is H, optionally substituted alkyl or optionally substituted aryl;

[0158] each R a and R' a is independently H, F, Cl, Br, I, -OR b , -SR b , -N(R b )2, -NO2, -CN, -C(=O)R b , -O-C(=O)R b , -C(=O)OR b , -C(=O)N(R b )2, -NR b -C(=O)-R b , -SO2-N(R b )2 or an optionally substituted group selected from alkyl, heteroatom-containing alkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl, aralkyl, alkaryl and heteroaryl;

[0159] two adjacent R a or R' a groups can form, together with the carbon atom to which they are attached, a 5- to 8-membered ring;

[0160] each R b independently H or an optionally substituted group selected from alkyl, heteroatom-containing alkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl, aralkyl, alkaryl and heteroaryl.

[0161] More particularly, each chromophore moiety Q can independently be a benzophenone moiety according to the following formula (A1) or a thioxanthone moiety according to the following formula (B1):

[0162]

[0163] wherein

[0164] each R c independently H, alkyl, Ar, -S-Ar or -O-Ar (wherein Ar is aryl), in particular H, methyl, Ph, -S-Ph or -O-Ph (wherein Ph is phenyl);

[0165] each R' c independently H or alkyl, in particular H or methyl;

[0166] each R d independently H, halogen, alkoxy, alkyl or -C(=0)-Ar (wherein Ar is aryl), in particular H, F, Cl, methyl, ethyl, isopropyl or -C(=0)-Ph (wherein Ph is phenyl).

[0167] In preferred embodiments, all Q moieties have the same structure. In particular, each chromophore moiety Q can be a benzophenone moiety according to formula (A1). Alternatively, each chromophore moiety Q can be a thioxanthone moiety according to formula (B1).

[0168] In the photoinitiators of formula (I) and (I-a) to (I-n), each chromophore moiety Q is attached to R 3 .

[0169] each R 3 independently a direct bond or a linker.

[0170] When Q is according to formula (A), then R 3 is preferably a direct bond.

[0171] When Q is according to formula (B), then R 3 is preferably a linker.

[0172] When Q is according to formula (B), E is S and R 3 is a direct bond, then X is preferably not -0-.

[0173] When R 3 is a direct bond, then X is preferably -NR 1 - -C(=0)-0- or -C(=0)-NR 1 -.

[0174] when R 3 is a linker, the linker can be a divalent linker comprising 1 to 15, preferably 1 to 10 carbon atoms. The linker can further optionally comprise one or more heteroatoms, such as O, N or S. For example, the linker can be a hydrocarbon linker, which optionally comprises one or more bonds selected from -0-, -S-, -NR l -, -C(=0)-, -0-C(=0)-, -C(=0)-0-, -NR l -C(=0)-, -C(=0)-NR l -, -0-C(=0)-0-, -NR l -C(=0)-0-, -0-C(=0)-NR l - and combinations thereof, wherein R l is H, alkyl or aryl.

[0175] when R 3 is a linker, the linker can be:

[0176] - an acyclic linker, which can be saturated or unsaturated, in particular an acyclic linker having 1 to 6, 1 to 4 or 1 to 2 carbon atoms; or

[0177] - a cyclic linker, which can be aromatic or non-aromatic, monocyclic or polycyclic, in particular a cyclic linker having 6 to 10, 7 to 9 or 7 to 8 carbon atoms.

[0178] In preferred embodiments, each R 3 is independently a direct bond, C1-C6 alkylene, C1-C6 oxyalkylene, C1-C6 alkenylene, C1-C6 thioalkylene, C1-C6 ketoalkylene or C1-C6 aminoalkylene.

[0179] More particularly, each R 3 may be independently a direct bond, alkylene of formula (C-1), oxyalkylene of formula (C-2), thioalkylene of formula (C-3), ketoalkylene of formula (C-4) or aminoalkylene of formula (C-5):

[0180]

[0181] wherein

[0182] each R m , R' m , R o , R' oR p R' p R q R' q R r and R' r are independently H or optionally substituted alkyl, in particular H;

[0183] R" r is H or optionally substituted alkyl;

[0184] f is 1, 2, 3, 4, 5 or 6, in particular 1 or 2;

[0185] g is 1, 2, 3, 4, 5 or 6, in particular 1 or 2;

[0186] h is 1, 2, 3, 4, 5 or 6, in particular 1 or 2;

[0187] i is 1, 2, 3, 4 or 5, in particular 1 ;

[0188] j is 1, 2, 3, 4, 5 or 6, in particular 1 or 2;

[0189] the symbol represents the point of attachment to the Q moiety;

[0190] the symbol represents the point of attachment to the X moiety.

[0191] More particularly, each R 3 may be independently selected from a direct bond, an alkylene of formula (C-1 ), an oxyalkylene of formula (C-2) and an aminoalkylene of formula (C-5). Even more particularly, each R 3 may be independently selected from a direct bond, an alkylene of formula (C-1 ) and an oxyalkylene of formula (C-2) as defined above. Still more particularly, each R 3 is independently an oxyalkylene of formula (C-2), in particular each R 3 is an oxyalkylene of formula (C-2), wherein R o and R' o are H and g is 1.

[0192] In the photoinitiators of formula (I) and (I-a) to (I-n), each R 3 is attached to X. X can correspond to the residue of an epoxide- reactive group, i.e. a group capable of opening an epoxide ring. Examples of epoxide-reactive groups are alcohols, thiols, primary and secondary amines, carboxylic acids and amides.

[0193] each X is independently -NR 1 -, -O-, -S-, -C(=O)-O- or -C(=O)-NR1 -; each R 1 independently is H, alkyl, or aryl, and the symbol represents the point of attachment to R 3 .

[0194] In particular, each X can independently be -NR 1 -, -O-, or -C(=0)-0-. More particularly, each X can independently be -NR 1 - or -C(=0)-0-. Still more particularly, each X is -C(=0)-0-.

[0195] In the photoinitiators of formula (I) and (I-a) to (I-n), each R 2 independently is a direct bond or a linking group. When R 2 is a linking group, the linking group can be divalent, trivalent, or tetravalent. When R 2 is a linking group, the linking group can be aliphatic or aromatic, in particular aliphatic.

[0196] In preferred embodiments, R 2 is a direct bond or a linking group other than a polyether linking group, in particular R 2 is a linking group other than a polyether linking group. As used herein, the term “linking group other than a polyether linking group” refers to a linking group that does not comprise consecutive repeating units derived from the ring-opening of a cyclic ether comprising 2 to 4 carbon atoms. In particular, the linking group other than a polyether can be free of a moiety containing more than one oxyalkylene unit, preferably the linking group other than a polyether does not comprise any oxyalkylene unit. More particularly, the linking group other than a polyether can be free of the following moiety -[0-A 1 ] z -, wherein A 1 is a C2-C4 alkylene and z is greater than 1, preferably the linking group other than a polyether does not comprise any -[0-A 1 ]- moiety, wherein A 1 is a C2-C4 alkylene. Even more particularly, the linking group other than a polyether can be free of more than one acyclic ether bond, preferably the linking group other than a polyether does not comprise any acyclic ether bond.

[0197] In particularly preferred embodiments, R 2 is a direct bond or a non-polymeric linking group, preferably R 2 is a non-polymeric linking group. As used herein, the term “non-polymeric linking group” refers to a linking group that does not comprise consecutive repeating units other than consecutive carbon atoms.

[0198] R 2may comprise 0 to 20, in particular 0 to 15, more particularly 0 to 10 carbon atoms. R 2 may comprise 0 to 2, in particular 0 to 1, more particularly 0 oxygen atoms. R 2 may comprise 0 to 2, in particular 0 to 1, more particularly 0 heteroatoms selected from O, N or S.

[0199] R 2 may have a molecular weight of less than 500 g / mol, in particular less than 400 g / mol, more particularly less than 300 g / mol, even more particularly less than 250 g / mol, still more particularly less than 200 g / mol.

[0200] In particular, each R 2 may independently be a direct bond or a linking group selected from alkylene, heteroatom-containing alkylene, alkenylene, heteroatom-containing alkenylene, cycloalkylene, heterocycloalkylene, arylene, heteroarylene, and combinations thereof. In particular, R 2 may be a direct bond or a linking group selected from alkylene, heteroatom-containing alkylene, cycloalkylene, arylene, and combinations thereof. More particularly, R 2 may be a linking group selected from alkylene, heteroatom-containing alkylene, cycloalkylene, arylene, and combinations thereof.

[0201] In one embodiment, R 2 may be an aromatic linking group, such as arylene, heteroarylene, or combinations thereof. In such cases, R 2 is preferably arylene.

[0202] For example, R 2 may be represented by one of the following formulae (3) to (9):

[0203]

[0204]

[0205] wherein

[0206] L is a direct bond or a linking group;

[0207] R e , R' e , and R" e are independently selected from H, alkyl, cycloalkyl, aryl, alkylaryl, arylalkyl, alkoxy, -C(=0)0-alkyl, and halogen atoms;

[0208] R f is H or methyl;

[0209] a, a', c, and c' are independently 0 or 1;

[0210] b is 1 or 2.

[0211] In particular, R 2 may be represented by one of formula (3) or (4) as defined above, preferably by formula (4). When R 2 When represented by formula (4), L can be selected from a direct bond, alkylene, -CR3R4-, -C(=0)-, -C(=0)-0-alkyl-0-C(=0)-, -SO-, -SO2-, -C(=CCl2)- and -CR5R6-Ph-CR7R8-;

[0212] wherein

[0213] R3and R4are independently selected from H, alkyl, cycloalkyl, aryl, haloalkyl and perfluoroalkyl, or R3and R4together with the carbon atom to which they are attached can form a ring;

[0214] R5, R6, R7and R8are independently selected from H, alkyl, cycloalkyl, aryl, haloalkyl and perfluoroalkyl;

[0215] Alk is alkylene;

[0216] Ph is phenylene optionally substituted by one or more groups selected from alkyl, cycloalkyl, aryl and halogen atoms.

[0217] More particularly, R 2 may correspond to the residue of an optionally substituted aromatic polyol, polyacid, polyamine, hydroxy acid or hydroxy amine (not containing OH, COOH and / or amino groups).

[0218] For example, R 2 may be an optionally substituted aromatic polyol, polyacid, polyamine, hydroxy acid or hydroxy amine residue comprising 1 to 3, preferably 1 or 2 aromatic rings, such as catechol, resorcinol, pyrocatechol, (hydroxymethyl)phenol, benzenedimethanol, hydroxybenzoic acid, o-phthalic acid, p-phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, bisphenol, diphenylene glycol, phloroglucinol, pyrogallol, tris(hydroxyphenyl)methane, tris(hydroxyphenyl)ethane, trimellitic acid, gallic acid, condensation products of an optionally substituted aromatic alcohol and formaldehyde (also known as novolacs), phenylene diamine, toluylene diamine, xylylene diamine, diaminobiphenyl, diaminodiphenyl ether, diaminodiphenylmethane, diaminodiphenylsulfone, aminophenol, (aminophenoxy)phenol.

[0219] Even more particularly, R 2may be a residue of an optionally substituted bisphenol. Examples of suitable bisphenols are bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol C2, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol-Z, di-nitro-bisphenol A, tetrabromo-bisphenol A, and combinations thereof.

[0220] In another embodiment, R 2 may be an aliphatic linking group, such as an alkylene group, a heteroatom-containing alkylene group, a cycloalkylene group, a heterocycloalkylene group, or a combination thereof. In such cases, R 2 is preferably an alkylene group, a heteroatom-containing alkylene group, a cycloalkylene group, or a combination thereof.

[0221] More particularly, R 2 may be represented by one of the following formulae (10) to (20):

[0222]

[0223] wherein

[0224] R' e and L are as defined above in formula (4);

[0225] each R g , R' g , R h , R i and R' i is independently H or an alkyl group;

[0226] each R j is independently H, an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, an alkoxy group, a -C(=0)0-alkyl group, and a halogen atom;

[0227] R k , R' k and R" k are independently an alkylene group or an alkenylene group;

[0228] d is 1 to 12;

[0229] e and e' are independently 0 or 1.

[0230] In particular, R 2 may be represented by one of formulae (10), (11), (12), (13), (15), (16), (17), or (19) as defined above, preferably by one of formulae (10), (11), or (12).

[0231] Alternatively, R 2 may be represented by one of formulae (10), (12), (13), or (14) as defined above, wherein

[0232] each R g , R' g and R h are independently H or alkyl, preferably H, methyl or ethyl;

[0233] d is 1 to 12, preferably 2 to 10.

[0234] R 2 may correspond to the residue of an optionally substituted aliphatic polyol, polyacid, polyamine, hydroxy acid or hydroxy amine (excluding OH, COOH and / or amino groups).

[0235] For example, R 2 may be the residue of an optionally substituted aliphatic polyol, polyacid, polyamine, hydroxy acid or hydroxy amine selected from ethylene glycol, 1,2- or 1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 3,3-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 3,3-butylethyl-1,5-pentanediol, cyclohexanediol, cyclohexane-1,4-dimethanol, norbornene dimethanol, norbornane dimethanol, tricyclodecane diol, tricyclodecane dimethanol, hydrogenated bisphenol A, B, F or S, trimethylolmethane, trimethyloloethane, trimethylolpropane, di(trimethylolpropane), pentaerythritol, glycerol, dianhydrohexitol (i.e. isosorbide, isomannide, isoidide), hydroxylated vegetable oil, tris(2-hydroxyethyl)isocyanurate, 1,2-ethanediamine, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,8-octamethylenediamine, 1,12-dodecamethylenediamine, isophorone diamine, diaminocyclohexane, methylcyclohexane diamine, bis(aminomethyl)cyclohexane, diaminodecahydronaphthalene, dimethyldiaminodicyclohexylmethane, diaminodicyclohexylmethane, bis(aminomethyl)norbornane, propanedioic acid, succinic acid, 2-methylsuccinic acid, 2,2-dimethylsuccinic acid, glutaric acid, 3,3-diethylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, citric acid, 1,2-, 1,3- or 1,4cyclohexanedicarboxylic acid, glycolic acid, 12-hydroxystearic acid, ethanolamine, diethanolamine.

[0236] alternatively, R2 This can correspond to residues in epoxidized polyunsaturated compounds (i.e., compounds having at least two non-aromatic carbon-carbon double bonds that have been epoxidized). As used herein, the term "residues of an epoxidized polyunsaturated compound" refers to residues obtained by removing the end groups containing the epoxide ring from the compound. For example, if an epoxidized polyunsaturated compound has the following formula:

[0237]

[0238] The residues of the epoxidized polyunsaturated compound correspond to the following formula:

[0239] .

[0240] Optionally, R 2 This can correspond to residues in epoxidized oils. As used herein, the term "residues in epoxidized oils" refers to residues obtained by removing epoxide-containing end groups from the oil. For example, if an epoxidized oil has the following formula:

[0241]

[0242] in

[0243] Each R 4 Independently, it is H, an alkyl group that has been optionally substituted, or an alkenyl group that has been optionally substituted;

[0244] R k 、R' k and R" k It is independently an alkylene or alkenylene group;

[0245] The residues of the epoxidized oil correspond to the following formula:

[0246] .

[0247] When n1 is 0, R 2 The preferred choice is one of formulas (3) to (19).

[0248] When n2 is 0, R 2 Preferably, it is a direct bond or an alkylene bond.

[0249] When both n1 and n2 are not 0, R 2 Preferably, it is a direct bond or an alkylene bond.

[0250] In the photoinitiators of formulas (I) and (Ia) to (In), each R 4 Independently, it is H, an optionally substituted alkyl group, or an optionally substituted alkenyl group. In one embodiment, each R... 4 It is H. In another embodiment, each R4 is H and the other part R 4 is H and the other part R 4 is H and the other part R 4 is H.

[0251] When R 2 is of the formula (1) part wherein R 4 is optionally substituted alkyl, then Y is preferably a direct bond.

[0252] In the photoinitiators of formula (I), (I-c), (I-d) and (I-g), each R 5 is independently H, alkyl, aryl or -CH2-CH(OH)-CH2-X-R 3 -Q. In particular, each R 5 is independently H, alkyl or -CH2-CH(OH)-CH2-X-R 3 -Q.

[0253] In a particularly preferred embodiment, the photoinitiator of formula (I) is according to one of the following formulae (I-a), (I-b), (I-c) or (I-e), preferably according to one of formulae (I-a) or (I-e), more preferably according to formula (I-a):

[0254]

[0255]

[0256] wherein

[0257] n3, n4, n5 and n7 are independently 2, 3 or 4, preferably 2 or 3;

[0258] each chromophore moiety Q is according to formula (A) or (B) as defined above, preferably each chromophore moiety Q is according to formula (A1) or (B1) as defined above, more preferably each chromophore moiety Q is according to formula (B1) as defined above;

[0259] each X is independently -NR 1 -, -O- or , preferably -NR 1 - or , more preferably ;

[0260] each R 1 is independently H or alkyl;

[0261] each R 2independently is alkylene or heteroatom-containing alkylene, preferably alkylene, more preferably alkylene represented by one of formulae (10), (12), (13) or (14) as defined above;

[0262] each R 3 independently is a direct bond, alkylene of formula (C-1) as defined above, oxyalkylene of formula (C-2) as defined above or aminoalkylene of formula (C-5) as defined above, preferably a direct bond, alkylene of formula (C-1) or oxyalkylene of formula (C-2), more preferably oxyalkylene of formula (C-2);

[0263] each R 4 is H;

[0264] each R 5 independently is H, alkyl or -CH2-CH(OH)-CH2-X-R 3 -Q, wherein X, R 3 and Q are as defined above;

[0265] the symbol represents the point of attachment to R 3 .

[0266] In a particularly preferred embodiment, the photoinitiator of formula (I) is according to one of the following formulae (I-1) to (I-9):

[0267]

[0268]

[0269]

[0270] Process for obtaining photoinitiators

[0271] The present application also relates to a process for the preparation of a photoinitiator. The process can be used for the preparation of a photoinitiator according to the present application. The process comprises the step of reacting a polyepoxide component with a component bearing a chromophore, said component bearing a chromophore having at least one epoxide-reactive group (i.e. a group capable of opening an epoxide ring). Thus, the opening of the epoxide ring of the polyepoxide component forms a free hydroxyl group, which can be used for further reactions, e.g. using the photoinitiator to obtain a photoreactive urethane oligomer, a photoreactive polyester oligomer or a polymerizable photoinitiator (as detailed below).

[0272] The photo-initiator of the present application can be obtained using n equivalents of the component bearing a chromophore per equivalent of the polyepoxide component. As used herein, n is the number of moles of epoxide rings present in the polyepoxide component. The value of n can be obtained by multiplying the number of moles of the polyepoxide component by its epoxide functionality, i.e. the number of epoxide rings on the polyepoxide compound. For example, if the photo-initiator of the present application is obtained using 1 mole of a polyepoxide compound bearing two epoxide rings, n is equal to 2. If the polyepoxide component comprises a mixture of polyepoxide compounds, n corresponds to the total number of moles of epoxide rings in the mixture.

[0273] The reaction between the polyepoxide component and the component bearing a chromophore can be carried out in the presence of at least one catalyst. The catalyst can be any substance capable of catalysing the ring opening of epoxide, in particular when the epoxide-reactive group of the component bearing a chromophore is a carboxylic acid, an alcohol or a thiol. In particular, the catalyst can be selected from:

[0274] - metal halides, such as iron chloride, aluminium chloride or boron trifluoride;

[0275] - quaternary ammonium salts, such as benzyltriethylammonium chloride, tetrapropylammonium chloride or tetrabutylammonium bromide;

[0276] - mineral acids, for example sulphuric acid,

[0277] - organic acids, such as acetic acid, trifluoromethanesulfonic anhydride ((CF3SO2)20, Tf20), methanesulfonic anhydride ((CH3SO2)20), trifluoroacetic anhydride ((CF3CO)20), acetic anhydride ((CH3CO)20)

[0278] - organometallic compounds, such as tin catalysts (e.g. dibutyltin dilaurate), carboxylate complex of bismuth (e.g. bismuth octoate or bismuth neodecanoate); acetylacetonate complex of zirconium; acetylacetonate complex of hafnium; acetylacetonate complex of titanium; acetylacetonate complex of zirconium; diketiminate complex of hafnium; diketiminate complex of titanium; amidinate complex of hafnium; amidinate complex of titanium; carboxylate complex of zinc; - diketiminate complex of hafnium; diketiminate complex of titanium; amidinate complex of hafnium; amidinate complex of titanium; carboxylate complex of zinc; - diketiminate complex of hafnium; diketiminate complex of titanium; amidinate complex of hafnium; amidinate complex of titanium; carboxylate complex of zinc; - diketiminate complex of hafnium; diketiminate complex of titanium; amidinate complex of hafnium; amidinate complex of titanium; carboxylate complex of zinc;

[0279] - quaternary ammonium salts, such as benzyltriethylammonium chloride, tetrapropylammonium chloride or tetrabutylammonium bromide; - quaternary ammonium salts, such as benzyltriethylammonium chloride, tetrapropylammonium chloride or tetrabutylammonium bromide; - quaternary ammonium salts, such as benzyltriethylammonium chloride, tetrapropylammonium chloride or tetrabutylammonium bromide; ,

[0280] - tertiary amines, such as 2-phenylimidazoline,

[0281] - tertiary phosphines, such as triphenylphosphine;

[0282] and combinations thereof.

[0283] The amount of catalyst can be less than 5 wt%, less than 2 wt%, less than 1 wt%, or even less than 0.5 wt%, based on the total weight of the polyepoxide component and the component with a chromophore.

[0284] The reaction between the polyepoxide component and the component with a chromophore can be carried out in the presence of a stabilizer, in particular a stabilizer selected from the group consisting of hydroquinone (HQ), hydroquinone monomethyl ether (MEHQ, 4-methoxyphenol), 4-tert-butylcatechol (TBC), and 3,5-di-tert-butyl-4-hydroxytoluene (BHT), phenothiazine (PTZ), and mixtures thereof.

[0285] The reaction between the polyepoxide component and the component with a chromophore can be carried out in the presence of a solvent. Alternatively, the process can not require the presence of a solvent. As used herein, the term “solvent” refers to a non-reactive organic solvent, i.e., a solvent that does not react with other components used to make the self-crosslinkable urethane (meth)acrylate.

[0286] Examples of suitable solvents include aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, octane, cyclohexane, or methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, or xylene; halogenated hydrocarbons such as dichloromethane, chloroform, or trichloroethane; ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclopentanone, or cyclohexanone; esters such as methyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, or butyl acetate; ethers such as diethyl ether, diisopropyl ether, dibutyl ether, ethylene glycol diethyl ether, tetrahydrofuran, or tetrahydropyran; carbonates such as diethyl carbonate; and combinations thereof.

[0287] The reaction between the polyepoxide component and the component with a chromophore can be carried out at a temperature of 50 to 150 °C, in particular 70 to 130 °C.

[0288] The reaction between the polyepoxide component and the component with a chromophore can be carried out until the epoxide reactivity value (ERV) and / or the epoxy value (EV) is less than 10 mg KOH / g, in particular less than 5 mg KOH / g, more particularly less than 2 mg KOH / g. The AV and / or EV can be adjusted as needed by adding more polyepoxide component or component with a chromophore as the reaction proceeds.

[0289] The reaction between the polyepoxide component and the component with a chromophore can be carried out for a time of 1 to 72 hours, in particular 2 to 24 hours.

[0290] Once the reaction is complete, the reaction medium can be washed one or more times with an aqueous solution, for example an aqueous solution of sodium chloride. The solvent can be evaporated from the resulting organic phase.

[0291] Component a) with chromophore

[0292] The photoinitiator of the present application can be derived from the reaction of one or more compounds bearing a chromophore. The one or more compounds bearing a chromophore used to obtain the photoinitiator are referred to herein as component a).

[0293] As used herein, the term "compound bearing a chromophore" refers to a compound bearing at least one chromophore moiety as defined above. In particular, the chromophore moiety can correspond to the chromophore moiety Q as defined above for the photoinitiator of the present application.

[0294] The compound bearing a chromophore further bears at least one epoxide-reactive group. In particular, the epoxide-reactive group can correspond to -X-H, wherein X is as defined above for the photoinitiator of the present application. More particularly, the epoxide-reactive group -X-H can correspond to one of the following groups: -NHR 1 , -OH, -SH, -C(=0)-OH or -C(=0)-NHR 1 wherein R 1 is independently H, alkyl or aryl.

[0295] In particular, component a) can comprise, consist of, or consist essentially of at least one compound according to the following formula (II):

[0296]

[0297] wherein Q, X and R 3 are as defined above.

[0298] All preferred embodiments of Q, X and R 3 above for the photoinitiator of the present application apply equally to component a).

[0299] More particularly, the compound bearing a chromophore of component a) can comprise, consist of, or consist essentially of at least one compound according to formulae (II-a) to (II-f):

[0300]

[0301] wherein

[0302] R 3is selected from a direct bond, an alkylene group of formula (C-1) as defined above, an oxyalkylene group of formula (C-2) as defined above, and an aminoalkylene group of formula (C-5) as defined above, preferably an oxyalkylene group of formula (C-2);

[0303] each R c independently H, alkyl, Ar, -S-Ar, or -O-Ar (wherein Ar is aryl), in particular H, methyl, Ph, -S-Ph, or -O-Ph (wherein Ph is phenyl);

[0304] each R c independently H or alkyl, in particular H or methyl;

[0305] each R d independently H, halogen, alkoxy, alkyl, or -C(=0)-Ar (wherein Ar is aryl), in particular H, F, CI, methyl, ethyl, isopropyl, or -C(=0)-Ph (wherein Ph is phenyl).

[0306] Even more particularly, the component a) carrying a chromophore can comprise, consist of, or consist essentially of a compound according to formula (II-e).

[0307] Polyepoxide component b)

[0308] The photoinitiator of the present application is derived from the reaction of one or more polyepoxide compounds. The one or more polyepoxide compounds used to obtain the photoinitiator are referred to herein as component b).

[0309] As used herein, the term “polyepoxide compound” refers to a compound carrying at least two epoxide rings.

[0310] The epoxide rings can be comprised in one or more of the following groups: glycidyl ether groups, glycidyl ester groups, glycidyl amine groups, glycidyl amide groups, alicyclic epoxide groups, epoxidized epoxy groups derived from non-cyclic carbon-carbon double bonds, and combinations thereof.

[0311] The polyepoxide compound can carry two epoxide rings. In particular, the polyepoxide compound can carry two glycidyl ether groups, two glycidyl ester groups, or two epoxidized epoxy groups derived from non-cyclic carbon-carbon double bonds.

[0312] The polyepoxide compound can carry three epoxide rings. In particular, the polyepoxide compound can carry three glycidyl ether groups.

[0313] The polyepoxide compound can carry four epoxide rings. In particular, the polyepoxide compound can carry four glycidyl ether groups.

[0314] In particular, component b) can comprise, consist of, or consist essentially of at least one compound according to the following formula (III):

[0315]

[0316] wherein

[0317] n1 is 0, 1, 2, 3, or 4;

[0318] n2 is 0, 1, 2, 3, or 4;

[0319] the sum of n1 + n2 is equal to 1, 2, 3, or 4;

[0320] each Y is independently a direct bond, -O-CH2-, -C(=0)-0-CH2-, -NR 6 -CH2- or -C(=0)-NR 7 -CH2-;

[0321] each Z is independently a direct bond, -CH2-0-C(=0))- or -C(=0)-0- ;

[0322] R 2 is a direct bond or a linker;

[0323] each R 4 is independently H, optionally substituted alkyl, or optionally substituted alkenyl;

[0324] each R 6 and R 7 are independently H, alkyl, aryl, or glycidyl according to the following formula: ;

[0325] the symbol denotes the point of attachment to R 2 .

[0326] All preferred embodiments of n1, n2, Y, Z, R 2 and R 4 described above for the photoinitiators of the present application apply equally to component b).

[0327] More particularly, component b) can comprise, consist of, or consist essentially of at least one compound according to one of the following formulae (III-a) to (III-n):

[0328]

[0329]

[0330] wherein

[0331] R 2 , R 4 and R 5 as defined herein;

[0332] n'3, n'4, n'7, n' 14 and n' 15 are independently 2, 3 or 4, preferably 2 or 3;

[0333] n'5 and n'6 are independently 1 or 2, preferably 2;

[0334] n'8 is 1, 2 or 3, preferably 2;

[0335] n'9 is 1, 2 or 3, preferably 1 ;

[0336] n' 10 , n' 11 , n' 16 , n' 17 , n' 18 , n' 19 , n' 20 , n' 21 , n' 22 and n' 23 are independently 1 or 2, preferably 1 ;

[0337] n' 12 and n' 13 are independently 1, 2 or 3, preferably 1.

[0338] Compounds of formula (III-a), (III-b), (III-c), (III-e), (III-f), (III-g) and (III-h) are preferred. Compounds of formula (III-a), (III-b), (III-c) and (III-e) are particularly preferred. Compounds of formula (III-a) are more particularly preferred.

[0339] Even more particularly, component b) can comprise, consist of, or consist essentially of at least one compound selected from, but not limited to, the following: a diglycidyl ether, 1,2,3,4-diepoxybutane, 1,2,4,5-diepoxy-pentane, 1,2,5,6-diepoxyhexane, 1,2,7,8-diepoxyoctane, 1,2,9,10-diepoxydecane, ethylene glycol diglycidyl ether, 1,2- or 1,3-propanediol diglycidyl ether, 1,2-, 1,3- or 1,4-butanediol diglycidyl ether, 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 2-methyl-1,3-propanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 2,2-diethyl-1,3-propanediol diglycidyl ether, 3-methyl-1,5-pentanediol diglycidyl ether, 3,3-dimethyl-1,5-pentanediol diglycidyl ether, 2,4-diethyl-1,5-pentanediol diglycidyl ether, 3,3-butylethyl-1,5-pentanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolmethane triglycidyl ether, trimethyloloethane triglycidyl ether, trimethylolpropane triglycidyl ether, di(trimethylolpropane)tetraglycidyl ether, pentaerythritol tetraglycidyl ether, cyclohexane dicarboxylic acid diglycidyl ester, cyclohexane diglycidyl ether, cyclohexane-1,4-dimethanol diglycidyl ether, tricyclodecane dimethanol diglycidyl ether, isosorbide diglycidyl ether, o-dihydroxybenzene diglycidyl ether, m-dihydroxybenzene diglycidyl ether, cardol diglycidyl ether, m-phloroglucinol triglycidyl ether, pyrogallol triglycidyl ether, tris(hydroxyphenyl)methane triglycidyl ether, tris(hydroxyphenyl)ethane triglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol B diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, bisphenol A diglycidyl ether, bisphenol AP diglycidyl ether, bisphenol AF diglycidyl ether, bisphenol B diglycidyl ether, bisphenol BP diglycidyl ether, bisphenol C diglycidyl ether, bisphenol C2 diglycidyl ether, bisphenol F diglycidyl ether, bisphenol G diglycidyl ether, bisphenol M diglycidyl ether, bisphenol S diglycidyl ether, bisphenol P diglycidyl ether, bisphenol PH diglycidyl ether, bisphenol TMC diglycidyl ether, bisphenol Z diglycidyl ether, dinitro-bisphenol A diglycidyl ether, tetrabromo-bisphenol A diglycidyl ether, o-phthalic acid diglycidyl ester, p-phthalic acid diglycidyl ester, m-phthalic acid diglycidyl ester, 4-(diglycidylamino)phenyl glycidyl ether, 4,4'-methylenebis(N,N-diglycidylaniline), 4-[4-[bis(oxiran-2-ylmethyl)amino]phenoxy]-N,N-bis(ethylene oxide-2-ylmethyl)aniline, 4-(2-(4-(bis(ethylene oxide-2-ylmethyl)amino)phenoxy)ethoxy)-N,N-bis(ethylene oxide-2-ylmethyl)phenylamine, limonene dioxide (4-vinyl-1-cyclohexene diepoxide), epoxidized vegetable oils, triglycidyl isocyanurate, or combinations thereof.

[0340] More specifically, component b) may comprise, or consist substantially of, at least one compound selected from 1,2,7,8-diepoxyoctane, trimethylolpropane triglycidyl ether and 1,4-butanediol diglycidyl ether.

[0341] Use

[0342] The photoinitiator of the present invention can be used as a photoinitiating system in compositions capable of radiation curing, particularly in compositions capable of UV or LED curing.

[0343] As used herein, "UV-curable composition" means a composition that is at least partially cured by exposure to UV light emitted by a mercury light source (especially a mercury vapor lamp), and "LED-curable composition" means a composition that is at least partially cured by exposure to UV light emitted by an LED light source (especially an LED light source having an emission band in the range of 365-420 nm).

[0344] Other curing methods can be combined with UV light, such as heating.

[0345] The photoinitiator of the present invention can be used in photopolymerization reactions. Photopolymerization reactions can be used to photopolymerize (e.g., cure) one or more olefinically unsaturated compounds. As used herein, the term "olefinically unsaturated compound" refers to a compound containing a polymerizable carbon-carbon double bond. A polymerizable carbon-carbon double bond is a carbon-carbon double bond that can react with another carbon-carbon double bond in a polymerization reaction. A polymerizable carbon-carbon double bond is generally contained in a group selected from acrylates (including cyanoacrylates), methacrylates, acrylamide, methacrylamide, styrene, maleate, fumarate, itaconic acid, allyl, propenyl, vinyl, and combinations thereof, preferably selected from acrylates, methacrylates, and vinyl, and more preferably selected from acrylates and methacrylates. Carbon-carbon double bonds on a benzene ring are not considered polymerizable carbon-carbon double bonds.

[0346] In one embodiment, the olefinic unsaturated compound comprises a (meth)acrylate-functionalized compound, particularly a (meth)acrylate-functionalized compound selected from (meth)acrylate-functionalized monomers, (meth)acrylate-functionalized oligomers, amine-modified acrylates, and mixtures thereof.

[0347] The photoinitiator of the present invention can be used to obtain photoreactive oligomers. Photoreactive oligomers can be obtained by reacting the photoinitiator of the present invention with at least one compound having at least two hydroxyl reactive groups (i.e., groups that can react with the hydroxyl groups of the photoinitiator). Examples of suitable hydroxyl reactive groups include isocyanate groups and carboxylic acid groups, and their derivatives (i.e., esters and anhydrides). For example, the photoinitiator of the present invention can be used to obtain photoreactive urethane oligomers, i.e., by using the photoinitiator as part or all of the polyol component that reacts with a polyisocyanate component to provide the urethane oligomer.

[0348] Carbamate oligomers possessing a photoreactive moiety in their main chain can be called photoreactive carbamate oligomers. Specifically, photoreactive carbamate oligomers can be photoreactive carbamate (meth)acrylate oligomers. Photoreactive carbamate (meth)acrylate oligomers can be obtained by reacting the following substances:

[0349] a) A polyol component comprising at least one photoinitiator of formula (I) according to the invention and optionally one or more other polyols;

[0350] b) Polyisocyanate components; and

[0351] c) Hydroxyl-functionalized (meth)acrylate components.

[0352] Photoreactive urethane oligomers can be used in combination with one or more olefinically unsaturated compounds as defined above to provide curable compositions. In particular, curable compositions can be coating compositions, ink compositions, varnish compositions, encapsulation or potting compositions, 3D printing compositions, molding compositions, sealant compositions, adhesive compositions, nail polish compositions, or dental compositions.

[0353] Curable compositions comprising photoreactive urethane oligomers based on the photoinitiator of the present invention can advantageously eliminate the need for additional photoinitiators. Compared to compositions comprising conventional urethane oligomers and additional photoinitiators, the cured products obtained by curing such curable compositions exhibit a reduced amount of extractable material.

[0354] The photoinitiator of the present invention can be used to obtain photoreactive polyester oligomers, i.e., by using the photoinitiator as part or all of the polyol component that reacts with the polyacid component to provide the polyester oligomer.

[0355] The photoinitiator of the present invention can be used to obtain a polymerizable photoinitiator, namely, by reacting at least a portion of the hydroxyl groups of the photoinitiator with a (meth)acrylating agent (e.g., (meth)acrylic acid, (meth)acrylic anhydride, or (meth)acryloyl chloride) to convert them into (meth)acrylate groups.

[0356] The invention will be described in more detail with reference to the following embodiments, but it should be understood that the invention is not intended to be limited thereto.

[0357] Examples

[0358] Example 1:

[0359] The thioxanthone (TX)-based diol of formula (Io) was prepared according to the following scheme:

[0360]

[0361] 2-(carboxymethoxy)thioxanthone (31.8 g, 0.1054 mol, Lambson), 1,4-butanediol diglycidyl ether (GE-21 from CVC, 15 g, 0.1289 mol of epoxide ring), benzyltriethylammonium chloride (BTEAC, 0.14 g, 0.3 wt%, Aldrich) as catalyst, and 50 wt% cyclopentanone as process solvent were combined in a three-necked flask equipped with a mechanical stirrer under nitrogen atmosphere and heated to 125°C. The reaction was then carried out at 125°C until the shut-off criteria of acid value (AV) <2 mg KOH / g and epoxy value (EV) <2 mg KOH / g were reached (approximately 3 hours). AV or EV was adjusted as needed by adding more CMTX or 1,4-butanediol diglycidyl ether as the reaction proceeded. The final diol product (Io) was a dark brown liquid and exhibited acceptable FT-IR and 1 H NMR spectral characteristics.

[0362] Example 2:

[0363] The thioxanthone (TX)-based triol of formula (Ip) was prepared according to the following scheme:

[0364]

[0365] 2-(carboxymethoxy)thioxanone (CMTX, 35.2 g, 0.1167 mol), trimethylolpropane triglycidyl ether (18.7 g, 0.136 mol of epoxide ring, GE-30 from CVC), benzyltriethylammonium chloride (BTEAC, 0.14 g, 0.26 wt%) as catalyst, and cyclopentanone (54 g) as process solvent were mixed and heated to 130°C. The reaction was then carried out at 130°C until the shut-off criteria of acid value (AV) < 2 mg KOH / g and epoxy value (EV) < 2 mg KOH / g were reached (approximately 3 hours). AV or EV was adjusted as needed by adding more CMTX or trimethylolpropane triglycidyl ether as the reaction proceeded. The final product (Ip) exhibited the expected FT-IR and 1 A dark brown liquid with H NMR spectral characteristics.

[0366] Example 3:

[0367] The thioxanthone (TX)-based triol of formula (Iq) was prepared according to the following scheme:

[0368]

[0369] 2-(carboxymethoxy)thioxanthone (CMTX, 31.8 g, 0.1054 mol), 1,2,7,8-diepoxyoctane (7.49 g, approximately 0.105 mol of epoxide ring), benzyltriethylammonium chloride (BTEAC, 0.14 g, 0.3 wt%) as catalyst, and cyclopentanone (40 g, to produce approximately 50 wt% solution) as process solvent were combined in a three-necked flask equipped with a mechanical stirrer under nitrogen atmosphere and heated to 125°C. The reaction was carried out at 125°C until the shut-off criteria of AV < 2 mg KOH / g and EV < 2 mg KOH / g were reached (approximately 3 hours). AV or EV was adjusted as needed by adding more CMTX or 1,2,7,8-diepoxyoctane as the reaction proceeded. The final product (Iq) exhibited the expected FT-IR and 1 H NMR spectral characteristics.

[0370] In this specification, embodiments have been described in a manner that enables clear and concise writing; however, it is intended and will be understood that various combinations or separations of embodiments may be made without departing from the invention. For example, it should be understood that all preferred features described herein are applicable to all aspects of the invention described herein.

[0371] The foregoing description of various forms of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. In view of the foregoing teachings, many modifications or variations are possible. The forms discussed have been chosen and described to provide the best illustration of the principles of the invention and its practical application, thereby enabling those skilled in the art to utilize the invention in various forms and modifications suited to the particular intended use. All such modifications and variations are within the scope of the invention as defined by the appended claims when interpreted with the breadth of a fair, lawful, and just authorization.

Claims

1. A photoinitiator according to the following formula (I): wherein n1 is 0, 1, 2, 3 or 4; n2 is 0, 1, 2, 3 or 4; the sum of n1 + n2 is equal to 1, 2, 3 or 4; each Q is independently a chromophore moiety; each X is independently -NR 1 -, -O-, -S-, -C(=O)-O-, or -C(=O)-NR 1 -; each Y is independently a direct bond, -O-CH2-, -C(=O)-O-CH2-, -NR 5 -CH2- or -C(=O)-NR 5 -CH2-; each Z is independently a direct bond, -CH2-O-C(=O))- or -C(=O)-O-; or -C(=O)-O-; ; Each R 1 It is independently H, alkyl, or aryl; R 2 is a direct bond or a linker; Each R 3 It can be either a direct bond or a linker; Each R 4 Independently, it is H, an alkyl group that has been optionally substituted, or an alkenyl group that has been optionally substituted; each R is independently H, alkyl, aryl, or a group according to the formula: 5 is independently H, alkyl, aryl, or a group according to the formula: wherein Q, X and R 3 as defined above; Symbols represents the point of attachment to R 3 ; Symbols denotes the point of attachment to R 2 .

2. The photoinitiator according to claim 1, wherein n1 is 0, 1 or 2, more particularly n1 is 0.

3. The photoinitiator according to claim 1 or 2, wherein n2 is 2, 3 or 4, more particularly n2 is 2 or 3.

4. The photoinitiator according to any one of claims 1 to 3, wherein, the sum of n1 + n2 is equal to 2, 3 or 4, more particularly the sum of n1 + n2 is equal to 2 or 3.

5. The photoinitiator according to any one of claims 1 to 4, wherein the photoinitiator corresponds to one of the following formulae (I-a) to (I-n): wherein Q, X, R 2 , R 3 , R 4 and R 5 as defined in claim 1 ; n3, n4, n7, n 14 and n 15 are independently 2, 3 or 4, preferably 2 or 3; n5 and n6 are independently 1 or 2, preferably 2; n8 is 1, 2 or 3, preferably 2; n9 is 1, 2 or 3, preferably 1; n 10 , n 11 , n 16 , n 17 , n 18 , n 19 , n 20 , n 21 , n 22 and n 23 are independently 1 or 2, preferably 1 ; n 12 and n 13 is independently 1, 2 or 3, preferably 1.

6. The photoinitiator according to claim 5, wherein the photoinitiator corresponds to one of the formulae (I-a), (I-b), (I-c), (I-e), (I-f), (I-g) and (I-h), in particular to one of the formulae (I-a), (I-b), (I-c) and (I-e).

7. The photoinitiator according to claim 5, wherein the photoinitiator corresponds to the formula (I-a).

8. The photoinitiator according to any one of claims 1 to 7, wherein the photoinitiator comprises 2, 3 or 4 chromophore moieties Q.

9. The photoinitiator according to any one of claims 1-8, wherein each chromophore Q independently comprises a benzophenone moiety, a thioxanthone moiety, an anthraquinone moiety, The oxanone moiety or acridinone moiety; in particular, each chromophore moiety Q is independently a benzophenone moiety according to formula (A) or a thioxanone, anthraquinone, or other moiety according to formula (B). Tonone or acridinone fraction: wherein E is S, O, C(=0) or NR, in particular S; R is H, optionally substituted alkyl or optionally substituted aryl; each R a and R a are independently: H; F; Cl; Br; I; -OR b ; -SR b ; -N(R b )2; -NO2; -CN; -C(=O)R b ; -O-C(=O)R b ; -C(=O)OR b ; -C(=O)N(R b )2; -NR b -C(=O)-R b ; -SO2-N(R b )2; or an optionally substituted group selected from alkyl, heteroatom-containing alkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl, aralkyl, alkaryl and heteroaryl; two adjacent R a or R' a groups can form, together with the carbon atom to which they are attached, a 5- to 8-membered ring; Each R b Independently: H; or, a optionally substituted group selected from alkyl, heteroatom-containing alkyl, cycloalkyl, heterocycloalkyl, alkenyl, ynyl, aryl, aralkyl, alkylaryl, and heteroaryl.

10. The photoinitiator according to claim 9, wherein each chromophore moiety Q is a benzophenone moiety according to the following formula (A1): wherein Each R c Independently, it is H, alkyl, Ar, -S-Ar or -O-Ar, wherein Ar is aryl, especially H, methyl, Ph, -S-Ph or -O-Ph, wherein Ph is phenyl; each R' is independently H or alkyl, in particular H or methyl. c independently is H or alkyl, in particular H or methyl.

11. The photoinitiator according to claim 9, wherein each chromophore moiety Q is a thioxanthone moiety according to the following formula (B1): wherein Each R d Independently, it is H, halogen, alkoxy, alkyl, or -C(=O)-Ar, where Ar is aryl, and in particular, H, F, Cl, methyl, ethyl, isopropyl, or -C(=O)-Ph, where Ph is phenyl.

12. The photoinitiator according to any one of claims 1 to 11, wherein each R 3 is independently a direct bond or a divalent linker comprising 1 to 15, preferably 1 to 10, carbon atoms and optionally one or more heteroatoms such as O, N or S.

13. The photoinitiator according to any one of claims 1 to 12, wherein each R 3 is independently a direct bond, C1-C6alkylene, C1-C6oxyalkylene, C1-C6alkenylene, C1-C6thioalkylene, C1-C6ketoalkylene, or C1-C6aminoalkylene; In particular, each R 3 is independently a direct bond, an alkylene of formula (C-1), an oxyalkylene of formula (C-2), a thioalkylene of formula (C-3), a ketoalkylene of formula (C-4), or an aminoalkylene of formula (C-5) wherein each R m , R' m , R o , R' o , R p , R' p , R q , R' q , R r , and R' r are independently H or optionally substituted alkyl, particularly H; R" r is H or optionally substituted alkyl; f is 1, 2, 3, 4, 5 or 6, in particular 1 or 2; g is 1, 2, 3, 4, 5 or 6, in particular 1 or 2; h is 1, 2, 3, 4, 5 or 6, in particular 1 or 2; i is 1, 2, 3, 4 or 5, in particular 1; j is 1, 2, 3, 4, 5 or 6, in particular 1 or 2; Symbols represents the point of attachment to the Q moiety; Symbol represents the point of attachment to the X moiety.

14. The photoinitiator according to claim 13, wherein each R 3 is independently a direct bond, an alkylene of formula (C-1) or an oxyalkylene of formula (C-2), in particular, each R 3 is a direct bond, an alkylene of formula (C-1) or an oxyalkylene of formula (C-2).

15. The photoinitiator according to claim 13, wherein each R 3 independently is an oxyalkylene of formula (C-2), in particular, each R 3 is an oxyalkylene of formula (C-2), wherein R o and R' o is H and g is 1.

16. The photoinitiator according to any one of claims 1 to 15, wherein each X is independently -NR 1 -, -O- or -C(=O)-O-; in particular -NR 1 - or -C(=O)-O-.

17. The photoinitiator according to any one of claims 1 to 16, wherein each X is -C(=0)-0-.

18. The photoinitiator according to any one of claims 1 to 17, wherein each R 2 is independently a direct bond, an aromatic linker or an aliphatic linker; in particular, R 2 is an aliphatic linker.

19. The photoinitiator according to any one of claims 1 to 18, wherein each R 2 is independently a direct bond or a linking group other than a polyether linking group; in particular, each R 2 is independently a direct bond or a non-polymeric linking group.

20. The photoinitiator according to any one of claims 1-19, wherein each R 2 is independently a direct bond or a linking group selected from the group consisting of alkylene, heteroatom-containing alkylene, alkenylene, heteroatom-containing alkenylene, cycloalkylene, heterocycloalkylene, arylene, heteroarylene, and combinations thereof; In particular, R 2 is a direct bond or a linker selected from alkylene, heteroatom-containing alkylene, cycloalkylene, arylene, and combinations thereof.

21. The photoinitiator according to any one of claims 1 to 18, wherein each R 2 is a linking group other than a polyether linking group; in particular, each R 2 is a non-polymeric linking group.

22. The photoinitiator according to any one of claims 1-21, wherein each R 2 is a linker selected from the group consisting of alkylene, heteroatom-containing alkylene, cycloalkylene, arylene, and combinations thereof.

23. The photoinitiator according to any one of claims 1 to 22, wherein each R 2 is independently represented by one of the following formulae (10), (12), (13) or (14): wherein Each R g 、R' g and R h It is independently H or alkyl, preferably H, methyl or ethyl; d is 1 to 12, preferably 2 to 10.

24. The photoinitiator according to any one of claims 1 to 23, wherein each R 4 is H.

25. The photoinitiator according to any one of claims 6, 8 to 13, 16, and 18 to 24, wherein the photoinitiator is according to one of the following formulae (I-a), (I-b), (I-c) or (I-e), preferably according to one of the formulae (I-a) or (I-e), more preferably according to the formula (I-a): wherein n3, n4, n5 and n7 are independently 2, 3 or 4, preferably 2 or 3; each chromophore moiety Q is according to the formula (A) or (B) as defined in claim 9, preferably each chromophore moiety Q is according to the formula (A1) as defined in claim 10 or according to the formula (B1) as defined in claim 11, more preferably each chromophore moiety Q is according to the formula (B1) as defined in claim 11; each X is independently -NR 1 -, -O- or -C(=O)-O-, preferably -NR 1 - or -C(=O)-O-, more preferably -C(=O)-O-; each R is independently H or alkyl; 1 independently H or alkyl; Each R 2 It is independently an alkylene or a heteroatom-containing alkylene, preferably an alkylene, more preferably an alkylene represented by one of formulas (10), (12), (13) or (14) as defined in claim 23; Each R 3 Independently, it is a direct bond, an alkylene of formula (C-1) as defined in claim 13, an oxoalkylene of formula (C-2) as defined in claim 13, or an aminoalkylene of formula (C-5) as defined in claim 13, preferably a direct bond, an alkylene of formula (C-1) or an oxoalkylene of formula (C-2), more preferably an oxoalkylene of formula (C-2). Each R 4 It is H; each R 5 independently H, alkyl, aryl, or -CH2-CH(OH)-CH2-X-R 3 -Q, wherein X, R 3 and Q are as defined above; Symbols denotes the point of attachment to R 3 .

26. Photoinitiator according to claim 1, wherein the photoinitiator is according to one of the following formulae (I-1) to (I-9): 。 27. A process for the preparation of a photoinitiator by reacting a component a) bearing a chromophore with a polyepoxide component b); wherein, Component a) comprises at least one compound bearing at least one chromophore moiety and at least one epoxide-reactive group, and component b) comprises at least one compound bearing at least two epoxide rings.

28. Process according to claim 27, wherein the photoinitiator obtained with the process corresponds to the photoinitiator of formula (I) as defined in any one of claims 1 to 26.

29. Process according to claim 27 or 28, wherein component a) comprises at least one compound according to the following formula (II): wherein Q is a chromophore moiety; 30. Process according to any one of claims 27 to 29, wherein component a) comprises at least one compound according to one of the following formulae (II-a) to (II-f): X is -NR 1 -0-, -S-, -C(=0)-0- or -C(=0)-NR 1 -; and R 3 is a direct bond or a linker; symbols denotes the point of attachment to R 3 . wherein 31. Process according to claim 30, wherein component a) comprises at least one compound according to formula (II-e). R 3 is selected from a direct bond, an alkylene group of the formula (C-1) as defined in claim 13, an oxyalkylene group of the formula (C-2) as defined in claim 13, and an aminoalkylene group of the formula (C-5) as defined in claim 13, preferably an oxyalkylene group of the formula (C-2); Each R c Independently, it is H, alkyl, Ar, -S-Ar or -O-Ar, wherein Ar is aryl, and in particular, H, methyl, Ph, -S-Ph or -O-Ph, wherein Ph is phenyl; Each R' c It is independently H or alkyl, especially H or methyl; Each R d Independently, it is H, halogen, alkoxy, alkyl, or -C(=O)-Ar, where Ar is aryl, and in particular, H, F, Cl, methyl, ethyl, isopropyl, or -C(=O)-Ph, where Ph is phenyl.

32. Process according to any one of claims 27 to 31, wherein component b) comprises at least one compound according to the following formula (III): wherein n1 is 0, 1, 2, 3 or 4, preferably n1 is 0, 1 or 2, more preferably n1 is 0; n2 is 0, 1, 2, 3 or 4, preferably n2 is 2, 3 or 4, more preferably n2 is 2 or 3; the sum of n1 + n2 is equal to 1, 2, 3 or 4, preferably the sum of n1 + n2 is equal to 2, 3 or 4, more preferably the sum of n1 + n2 is equal to 2 or 3; 33. Process according to any one of claims 27 to 32, wherein component b) comprises at least one compound according to one of the following formulae (III-a) to (III-n): wherein n'5 and n'6 are independently 1 or 2, preferably 2; n'8 is 1, 2 or 3, preferably 2; n'9 is 1, 2 or 3, preferably 1; 34. Process according to claim 33, wherein component b) comprises at least one compound according to one of the formulae (III-a), (III-b), (III-c), (III-e), (III-f), (III-g) and (III-h), in particular according to one of the formulae (III-a), (III-b), (III-c) and (III-e).

35. Process according to claim 33, wherein component b) comprises at least one compound according to formula (III-a). each Y is independently a direct bond, -O-CH2-, -C(=O)-O-CH2-, -NR 6 -CH2- or -C(=O)-NR 7 -CH2-; each Z is independently a direct bond, -CH2-O-C(=O))- or -C(=O)-O-; or -C(=O)-O-; ; R 2 is a direct bond or a linker; Each R 4 Independently, it is H, an alkyl group that has been optionally substituted, or an alkenyl group that has been optionally substituted; each R is independently H, alkyl, aryl, or a glycidyl group of the formula 6 and R is independently H, alkyl, aryl, or a glycidyl group of the formula 7 each R is independently H, alkyl, aryl, or a glycidyl group of the formula each R is independently H symbols denotes the point of attachment to R 2 .

37. Process according to any one of claims 27 to 36, wherein component b) comprises at least one compound selected from 1,2,7,8-diepoxyoctane, trimethylolpropane triglycidyl ether and 1,4-butanediol diglycidyl ether.

38. Process according to any one of claims 27 to 37, wherein the reaction between component a) and component b) is carried out in the presence of at least one catalyst. R 2 as defined in any one of claims 18-23; R 4 is H; n'3, n'4, n'7, n' 14 and n' 15 is independently 2, 3 or 4, preferably 2 or 3; ​ ​ ​ n' 10 , n' 16 , n' 17 , n' 18 , n' 19 , n' 20 , n' 21 , n' 22 and n' 23 are independently 1 or 2, preferably 1 ; n' 12 and n' 13 is independently 1, 2 or 3, preferably 1. ​ ​ 36. The method of any one of claims 27-35, wherein component b) comprises at least one compound selected from the group consisting of a diglycidyl ether, 1,2,3,4-diepoxybutane, 1,2,4,5-diepoxy pentane, 1,2,5,6-diepoxyhexane, 1,2,7,8-diepoxyoctane, 1,2,9,10-diepoxydecane, ethylene glycol diglycidyl ether, 1,2- or 1,3-propanediol diglycidyl ether, 1,2-, 1,3- or 1,4-butanediol diglycidyl ether, 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,9-nonanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 1,12-dodecanediol diglycidyl ether, 2-methyl-1,3-propanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 2,2-diethyl-1,3-propanediol diglycidyl ether, 3-methyl-1,5-pentanediol diglycidyl ether, 3,3-dimethyl-1,5-pentanediol diglycidyl ether, 2,4-diethyl-1,5-pentanediol diglycidyl ether, 3,3-butylethyl-1,5-pentanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolmethane triglycidyl ether, trimethyloloethane triglycidyl ether, trimethylolpropane triglycidyl ether, di(trimethylolpropane)tetraglycidyl ether, pentaerythritol tetraglycidyl ether, cyclohexane dicarboxylic acid diglycidyl ester, cyclohexane diglycidyl ether, cyclohexane-1,4-dimethanol diglycidyl ether, tricyclodecane dimethanol diglycidyl ether, isosorbide diglycidyl ether, o-dihydroxybenzene diglycidyl ether, m-dihydroxybenzene diglycidyl ether, epi-nepholine diglycidyl ether, m-phloroglucinol triglycidyl ether, pyrogallol triglycidyl ether, tris(hydroxyphenyl)methane triglycidyl ether, tris(hydroxyphenyl)ethane triglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol B diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, bisphenol A diglycidyl ether, bisphenol AP diglycidyl ether, bisphenol AF diglycidyl ether, bisphenol B diglycidyl ether, bisphenol BP diglycidyl ether, bisphenol C diglycidyl ether, bisphenol C2 diglycidyl ether, bisphenol F diglycidyl ether, bisphenol G diglycidyl ether, bisphenol M diglycidyl ether, bisphenol S diglycidyl ether, bisphenol P diglycidyl ether, bisphenol PH diglycidyl ether, bisphenol TMC diglycidyl ether, bisphenol Z diglycidyl ether, dinitro-bisphenol A diglycidyl ether, tetrabromo-bisphenol A diglycidyl ether, o-phthalic acid diglycidyl ester, p-phthalic acid diglycidyl ester, m-phthalic acid diglycidyl ester, 4-(diglycidylamino)phenyl glycidyl ether, 4,4'-methylenebis(N,N-diglycidylaniline), 4-[4-[bis(oxiran-2-ylmethyl)amino]phenoxy]-N,N,N-bis(oxazolidine-2-ylmethyl)aniline, 4-(2-(4-(bis(oxazolidine-2- ylmethyl)amino)phenoxy)ethoxy)-N,N-bis(oxazolidine-2-ylmethyl)phenylamine, limonene dioxide (4-vinyl-1-cyclohexene diepoxide), epoxidized vegetable oil, triglycidyl isocyanurate, or combinations thereof. ​ ​ 39. The process according to any one of claims 27 to 38, wherein the reaction between component a) and component b) is carried out at a temperature of 50 to 150 °C, in particular 70 to 130 °C.

40. Use of a photoinitiator according to any one of claims 1 to 26 as photoinitiating system in a radiation-curable composition.

41. Use of a photoinitiator according to any one of claims 1 to 26 in a photopolymerization reaction.

42. The use according to claim 41, wherein the photoinitiator is used for the photopolymerization of one or more ethylenically unsaturated compounds.

43. Use of a photoinitiator according to any one of claims 1 to 26 for obtaining a photoreactive oligomer, in particular a photoreactive urethane oligomer, more particularly a photoreactive urethane (meth)acrylate oligomer.

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