Photoinitiator package comprising phosphine oxide photoinitiator, oxazole-based sensitizer and amine additive

Abstract

A photoinitiator package comprising one or more mono-or bisacylphosphine oxide photoinitiators, one or more oxazole-based sensitizers, and one or more amines, a photopolymerizable composition comprising the photoinitiator package and a suitable polymerizable compound, a process for polymerizing the photopolymerizable composition, and a method for preparing the photopolymerizable composition. The use of the photoinitiator package in photopolymerization applications, and the use of a combination of one or more amines and one or more oxazole-based sensitizers to increase the surface cure rate of a photopolymerizable composition comprising a Norrish Type-I photoinitiator.

Description

Technical Field

[0001] The present invention relates to a photoinitiator package comprising one or more monoacyl or bisacylphosphine oxide photoinitiators, one or more oxazole-based sensitizers and one or more amines, a photopolymerizable composition comprising the photoinitiator package and a suitable polymerizable compound, a method for polymerizing the photopolymerizable composition, the use of the photoinitiator package in photopolymerization applications, and the use of a combination of one or more amines and one or more oxazole-based sensitizers for increasing the surface cure rate of a photopolymerizable composition comprising a Norrish Type-I photoinitiator. Background Art

[0002] Photoinitiators used to promote free radical polymerization of ethylenically unsaturated compounds can be classified as Norrish Type-I, in which the electronically excited photoinitiator breaks to form free radicals for initiating free radical polymerization; or Norrish Type-II, in which the electronically excited photoinitiator abstracts a hydrogen radical from another molecule to form a free radical from the other molecule, which is used to initiate free radical polymerization. Although Type-II photoinitiators require the presence of certain additives / coinitiators, these additives / coinitiators are generally not required for Type-I photoinitiators.

[0003] The development of new Type-I photoinitiators is a key research area in the field of resin curing. In addition to providing new Type-I photoinitiators, Type-I photoinitiator packages are also provided, where the activity of the Type-I photoinitiator is enhanced by the presence of other compounds (such as photosensitizers). These compounds absorb light of a wavelength different from that of the photoinitiator itself and transfer the energy to the photoinitiator, thereby increasing the energy absorption of the photoinitiator.

[0004] Phosphine oxides are a well-known family of Type-I photoinitiators that offer excellent activity due to the formation of highly reactive phosphonyl radicals upon cleavage. Although excellent photoinitiators in deep cure systems, they are known to be much less effective at achieving surface cure. Therefore, blends of phosphine oxide photoinitiators with other photoinitiators known to be more effective at surface cure are often used to ensure thorough cure.

[0005] How different Type-I photoinitiators interact with sensitizers is difficult to predict and often depends on the structure and energy levels of the photoinitiator. It would be desirable to provide a highly active photoinitiator package because improved photopolymerization could be achieved without the need to develop new photoinitiators.

[0006] Furthermore, while the combination of Type-I photoinitiators and sensitizers is well established as a concept, it would be most beneficial to provide additional additives that further enhance the activity of the photoinitiator package. Summary of the invention

[0007] The present invention is based on the observation that the effect of certain sensitizers may be enhanced by the presence of amines, leading to an even further increase in the photoinitiator capacity.

[0008] Thus, in a first aspect, the present invention relates to a photoinitiator package comprising:

[0009] a) one or more monoacyl or bisacylphosphine oxide photoinitiators,

[0010] b) one or more oxazole-based sensitizers, each oxazole-based sensitizer having a structure according to formula (I):

[0011]

[0012] Where R 1 To R 4 Each independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 A group consisting of aromatic groups, to which R can be attached 1 and R 2 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C1-C 10 Alkyl and C6-

[0013] C 14 The aryl group is substituted with one or more substituents, and R 3 and R 4 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 substituted with one or more substituents from the group consisting of aryl; and

[0014] wherein A represents a linking group represented by any one of the following formulae (II) to (VI):

[0015]

[0016] wherein each * represents a bonding position of A in each formula; and

[0017] c) One or more amines.

[0018] In a second aspect, the present invention relates to a photopolymerizable composition comprising:

[0019] a) one or more ethylenically unsaturated free-radically polymerizable compounds;

[0020] b) A photoinitiator package according to the first aspect.

[0021] In a third aspect, the present invention relates to a method for photocuring photopolymerizable compositions, coatings, adhesives and inks, the method comprising the following steps in the given order:

[0022] a) coating or printing the photopolymerizable composition according to the second aspect onto a substrate, and

[0023] b) photopolymerizing the coated or printed composition on the substrate using a light source.

[0024] In a fourth aspect, the present invention relates to the use of the photoinitiator package according to the first aspect in the production of printing inks, screen printing inks, gravure printing inks, solder masks, etching offset inks, flexographic printing inks, gravure printing inks, inkjet inks, resist materials, insulators, sealants, image recording materials, solder masks, passivation layers, protective coatings, 3D printed objects and molds, holographic applications, optical fiber coatings, waveguides and lenses, overprint varnishes, wood, vinyl, metal and plastic coatings.

[0025] In a final aspect, the present invention relates to the use of a combination of one or more amines and one or more oxazole-based sensitizers for increasing the surface cure rate of a photopolymerizable composition comprising one or more Norrish Type-I photoinitiators.

[0026] definition

[0027] In the present specification, unless otherwise stated, the expression "alkyl" or "alkyl group" refers to a straight or branched saturated alkyl chain containing a given number of carbon atoms, and includes all possibilities for each number of carbon atoms in the alkyl group, i.e. for three carbon atoms: n-propyl and isopropyl; for four carbon atoms: n-butyl, isobutyl, sec-butyl and tert-butyl, etc.

[0028] The expression "aryl" or "aryl group" includes, for example, substituted or unsubstituted aryl groups such as substituted or unsubstituted phenyl groups, substituted or unsubstituted naphthyl groups, anthracenyl groups, indenyl groups, fluorenyl groups.

[0029] The expression "C1-C 40"Alkyl" means that, when more than one oxygen atom is present, the oxygen atoms are separated from each other by at least one methylene group, i.e., the oxygen atoms are discontinuous. Examples include the following: -OCH2OCH3, -OCH2CH2OCH2CH3, -O[CH2CH2O] v CH3, -O[CH2CH2O] v OH, -O[CH2CH2O] v CH2CH3, -CH2O[CH2CH2O] v CH3, -O[CH2CH2CH2O] p OH, -O[CH2CH2CH2O] p CH3, -O[CH2CH2CH2O] p CH2CH3, -CH2O[CH2CH2CH2O] p CH3, wherein v=1-19, wherein p=1-12.

[0030] When a group is substituted, the term "substituted" means that the group carries one or more substituents, and the substituents are preferably selected from halogen atoms, alkyl, cycloalkyl, alkoxy, alkylamino, dialkylamino, alkylthio or arylthio, heterocyclic groups; more preferably selected from methyl, ethyl, isopropyl, tert-butyl, phenyl, trifluoromethyl, cyano, acetyl, ethoxycarbonyl, carboxyl, carboxylate, amino, methylamino, dimethylamino, ethylamino, diethylamino, isopropylamino, diisopropylamino, cyclohexylamino, dicyclohexylamino, A methylamino group, an acetylamino group, a piperidino group, a pyrrolidinyl group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a pentyloxy group, a phenoxy group, a hydroxyl group, an acetoxy group, -PO3H, a methylthio group, an ethylthio group, an isopropylthio group, an n-propylthio group, a phenylthio group, a mercapto group, an acetylthio group, a thiocyanate group, a methylsulfinyl group, a methylsulfonyl group, a dimethanesulfonyl group, a sulfonate group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a trimethylsilyl group, a pentamethyldisilyl group, a triethylsilyl group, a trimethylstannyl group, a furyl group, a thienyl group, a pyridyl group, and a morpholinyl group.

[0031] The expression "direct bond" means that there is no linking group and a direct bond links the two moieties on either side.

[0032] A methylene group is a sp group attached to two hydrogen groups (i.e. -CH2R). 3 hybridized carbon, while the methanetriyl (or methyltriyl) group refers to a sp-2-carbon bonded to a hydrogen group (i.e. -CHR2). 3 Hybridized carbon.

[0033] Photoinitiators can be classified as Norrish Type-I, in which the electronically excited photoinitiator breaks apart to form free radicals for initiating free radical polymerization; or Norrish Type-II, in which the electronically excited photoinitiator abstracts a hydrogen radical from another molecule to form a free radical from the other molecule, which is used to initiate free radical polymerization, as is well understood by those skilled in the art. DETAILED DESCRIPTION

[0034] Monoacyl or bisacylphosphine oxide photoinitiator

[0035] One of the essential features of the photoinitiator package according to the present invention is one or more monoacyl or bisacylphosphine oxide photoinitiators.

[0036] In the broadest sense, any monoacyl or bisacylphosphine oxide photoinitiator may be used.

[0037] Suitable monoacylphosphine oxide photoinitiators include photoinitiators including, for example, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate, phenyl (2,4,6-trimethylbenzoyl)phosphinic acid, ethoxylated glycerol triesters (from IGM Resins BV), TP) or those described in US2017 / 0240659 and Speedcure XKM (from Lambson).

[0038] However, preference is given to using one or more bisacylphosphine oxide photoinitiators.

[0039] In the broadest sense, any monoacyl or bisacylphosphine oxide photoinitiator may be used; however, preferred are at least one, preferably all, of the one or more bisacylphosphine oxide photoinitiators having a structure according to any one of formulae (VII) to (X).

[0040] Formula (VII):

[0041]

[0042] Where R 1a , R 2a , R 3a , R 1b , R 2b and R 3b Each instance of is independently selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy or halogen;

[0043] Wherein X is selected from direct single bond, O, S, NR 5a, -CH2CO2- and -CH2CH2CO2-;

[0044] Where R 4a Selected from hydrogen, (CO)R 6a 、(CO)OR 6a 、(CO)NR 5a R 6a 、(SO2)R 6a 、[Si(R 7a )(R 8a )] m -Si(R 7a )(R 8a )(R 9a )、[Si(R 7a )(R 8a )O] m -Si(R 7a )(R 8a )(R 9a ); or

[0045] Where R 4a It is C1-C 28 Alkyl or one or more O, NR 5a , S, (CO), (CO)O or SO2 interrupted C2-C 28 Alkyl, wherein the C1-C 28 Alkyl or interrupted C2-C 28 The alkyl group is unsubstituted or is selected from OH, C6-C 14 Aryl, [Si(R 7a )(R 8a )] m -Si(R 7a )(R 8a )(R 9a )、[Si(R 7a )(R 8a )-O] m -Si(R 7a )(R 8a )(R 9a )、N(R 5a )2, 2-oxirane, unsubstituted or substituted by C1-C4 alkyl, C1-C4 alkoxy or substituted by OH C3-C 12 Cycloalkyl, substituted by one or more O, NR 5a or S interrupted C3-C 12 Cycloalkyl and interrupted C3-C 12The cycloalkyl group is unsubstituted or substituted by C1-C4 alkyl, C1-C4 alkoxy or substituted by OH, and the C6-C4 alkyl group is unsubstituted or substituted by C1-C4 alkyl, C1-C4 alkoxy or substituted by OH. 14 substituted with one or more substituents from the group consisting of aryl; or

[0046] Where R 4a is unsubstituted or replaced by one or more C1-C 12 Alkyl, C2-C interrupted by one or more O 20 Alkyl, C1-C 12 -C6-C substituted with alkoxy or OH 14 aryl; or

[0047] Where X is NR 5a In the case of R 4a With R 5a Together with the N-atom, it forms a 5- or 6-membered saturated ring, which is uninterrupted or terminated by O or NR 5a interrupted, and the uninterrupted or interrupted ring is unsubstituted or substituted with one or more C1-C4 alkyl, C1-C4 alkoxy or substituted with OH; or

[0048] Where R 4a Selected from the group consisting of structures (A) to (G):

[0049]

[0050] Where R 4a All options can be further selected from OH and R 17a One or more groups are substituted;

[0051] Where R 17a yes

[0052] Wherein A is PF6, SbF6, AsF6 or B(C6F5)4;

[0053] Where R 5a is hydrogen, (CO)R 6a , phenyl, C1-C 12 Alkyl, C2-C interrupted by one or more O 12 alkyl, unsubstituted or substituted by one or more C1-C4 alkyl, C1-C4 alkoxy, OH or C3-C4 substituted by NCO 12 Cycloalkyl, wherein the C1-C 12 Alkyl or interrupted C2-C 12 The alkyl group is unsubstituted or substituted by one or more C3-C7 cycloalkyl groups, OH or by NCO;

[0054] Where R 6a It is C1-C 12 Alkyl or C2-C interrupted by one or more O 12 Alkyl, wherein the C1-C 12 Alkyl or interrupted C2-C 12 Alkyl is unsubstituted or substituted by one or more C3-C7 cycloalkyl, OH, NCO or by phenyl substituted by NCO; or

[0055] Where R 6a is a C3-C4 alkyl group which is unsubstituted or substituted by one or more C1-C4 alkyl groups, OH groups or C1-C4 alkoxy groups. 12 Cycloalkyl or C2-C 10 alkenyl; or

[0056] Where R 6a is unsubstituted or replaced by C1-C 12 Alkyl, C1-C 12 Alkoxy, NCO-substituted or C1-C 12 Alkyl-substituted C6-C 14 aryl; or

[0057] If there is a group N(R 5a )2, then R 5a An example of (CO)R 6a , where R 5a and R 6a Another example is to form a 5- or 6-membered ring with the N and CO moieties, the 5- or 6-membered ring being uninterrupted or being replaced by O or NR 5a interrupted, and the uninterrupted or interrupted ring is unsubstituted or substituted with one or more C1-C4 alkyl, C1-C4 alkoxy or with OH;

[0058] Where R 7a , R 8a and R 9a Each independently selected from C1-C4 alkyl, C6-C 14 A group consisting of aryl or C1-C4 alkoxy;

[0059] Wherein m is an integer in the range of 0 to 10;

[0060] where Y 1a Selected from direct single bond, O, S, NR 5a , O(CO)-* or O(CO)CH2O-*, wherein the asterisk indicates a bond to the benzene ring of group (A), (B), (D) or (E);

[0061] where Y 2aSelect from direct single bond, O, S or NR 5a The group composed of;

[0062] Where R 11a and R 12a Independently of each other are C1-C 10 Alkyl, C2-C 10 alkenyl or phenyl, unsubstituted or substituted C1-C4 alkyl, or R 11a and R 12a Together with the C-atom to which they are attached they form a cyclohexane or cyclopentane ring;

[0063] Where Z a Is OH or NR 13a R 14a ;

[0064] Where Z 1a It is C1-C 12 Alkoxy or C2-C ... 12 Alkoxy, wherein the C1-C 12 Alkoxy or interrupted C2-C 12 Alkoxy groups are unsubstituted or substituted with OH;

[0065] Where R 13a and R 14a Independently of each other are C1-C 12 Alkyl, C1-C substituted by one or more OH or halogen 12 Alkyl; or

[0066] Where R 13a and R 14a Together with the N-atom to which they are attached, they form a 5- or 6-membered unsaturated or saturated ring which is uninterrupted or replaced by O or NR 15a interrupt, where R 15a is a C1-C4 alkyl group;

[0067] Where R 16a is hydrogen or C1-C4 alkyl; provided that

[0068] (i) If R 1a , R 2a and R 3a As the C1-C4 alkyl is methyl and X is O, then R 4 As C1-C 28 Alkyl is not methyl, ethyl, n-propyl, 2-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl;

[0069] (ii) If R 1a and R 3a As halogen, it is Cl, R2a is hydrogen and X is O, then R 4a As a replacement for C3-C 10 Alkylaryl is not 4-butyl-phenyl; and

[0070] (iii) If R 1a and R 3a As C1-C4 alkoxy is methoxy, R 2a is hydrogen, and X is NR 5a , and R 4a With R 5a If, together with the N-atom, it forms a 5- or 6-membered saturated ring, the ring is not a piperidine ring.

[0071] Formula (VIII):

[0072]

[0073] Among them, Ar 1 and Ar 2 Each independently is or unsubstituted or replaced by R 1c , R 2c , R 3c , R 4c or R 5c one or more substituted naphthyl;

[0074] Where R 1c and R 5c Each is independently selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy or halogen;

[0075] Where R 3c Selected from hydrogen, C1-C4 alkyl, halogen, C1-C4 alkoxy or C2-C4 interrupted by one or more O 20 A group consisting of alkoxy groups;

[0076] wherein Q is a C1-C4 alkylene group;

[0077] Where R 2c and R 4c independently of each other are hydrogen or PG c -Y c -Z c -X c -;

[0078] Among them PG c is a polymerizable group or a methyl group or an ethyl group;

[0079] where Y c is a direct single bond, O or S;

[0080] Where X cis a direct single bond, O or S;

[0081] Where Z c It is a direct single bond, C1-C 20 Alkylene or C2-C 20 Alkylene;

[0082] Where R 6c is unsubstituted or is selected from OH and C3-C 30 Alkyl; or

[0083] Where R 6c is a C3-C8 cycloalkylene group interrupted by one or more O or C3-C8 cycloalkylene groups. 28 Alkyl, and the interrupted C3-C 28 The alkyl group is unsubstituted or is selected from OH and One or more groups are substituted;

[0084] Formula (IX):

[0085]

[0086] Where R 1d is C1-C4 alkyl, C1-C4 alkoxy or halogen;

[0087] Where R 2d is hydrogen, C1-C4 alkyl, C1-C4 alkoxy or halogen; and

[0088] Where R 3d It is C1-C 20 Alkyl, cyclopentyl, cyclohexyl, phenyl-C1-C4 alkyl, naphthyl, biphenyl or 5- or 6-membered heterocyclic ring containing O, S or N, naphthyl, biphenyl and 5- or 6-membered heterocyclic ring containing O, S or N are unsubstituted or substituted by C1-C4 alkyl, C1-C4 alkoxy, halogen, C1-C4 alkylthio; or

[0089] Where R 3d yes

[0090] Where R 4d , R 5d , R 6d , R 7d and R 8d Each independently selected from hydrogen, halogen, C1-C 20 Alkyl, cyclopentyl, cyclohexyl, C2-C 12 Alkenyl, C2-C interrupted by one or more discontinuous O atoms 20 Alkyl, phenyl-C1-C4 alkyl, C1-C 20The group consisting of alkoxy or phenyl which is unsubstituted or substituted by one or two C1-C4 alkyl and / or C1-C4 alkoxy substituents.

[0091] Formula (V):

[0092]

[0093] Each A independently represents O, S, NR 3e ;

[0094] Where G is a multifunctional compound (core) G-(AH) p+q A residue of wherein each AH represents an alcohol group or an amino group or a thiol group;

[0095] wherein p and q are both integers, p+q is an integer in the range of 3 to 10, and p is an integer in the range of 3 to 8;

[0096] Where R 1e and R 2e Each independently selected from C1-C 18 Alkyl, C6-C 14 Aryl and C5-C 12 a group consisting of cycloalkyl radicals, each of which is uninterrupted or interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted amino radicals, or R 1e and R 2e is a five- to six-membered heterocyclic group containing oxygen and / or nitrogen and / or sulfur atoms; wherein each of the groups may be substituted by an aryl group, an alkyl group, an aryloxy group, an alkoxy group, a heteroatom and / or a heterocyclic group; R 2e It can also be (CO)R 1e ;

[0097] Where R3 e It is hydrogen or C1-C4 alkyl.

[0098] In one embodiment, at least one of the one or more bisacylphosphine oxide photoinitiators each has a structure according to formula (XI):

[0099]

[0100] Where R 1f Each instance of is independently selected from the group consisting of C1-C4 alkyl;

[0101] Where X f Selected from direct single bond, O, S, NR 4f , -CH2CO2- and -CH2CH2CO2-;

[0102] Where R 2fChoose from C1-C 40 Alkyl and C2-C8 interrupted by one or more O or C3-C8 cycloalkylene 40 The group consisting of alkyl groups, wherein the C1-C 40 Alkyl or interrupted C2-C 40 The alkyl group may be unsubstituted or selected from OH and R 3f One or more groups are substituted;

[0103] Where R 3f yes

[0104] Where R 4f Selected from hydrogen, (CO)R 5f , phenyl, C1-C 12 Alkyl, C2-C interrupted by one or more O 12 Alkyl, unsubstituted or substituted by one or more C1-C4 alkyl, C1-C4 alkoxy, OH or C3-C4 substituted by NCO 12 The group consisting of cycloalkyl, wherein the C1-C 12 Alkyl or interrupted C2-C 12 The alkyl group is unsubstituted or substituted by one or more C3-C7 cycloalkyl groups, OH or by NCO; and

[0105] Where R 5f Choose from C1-C 12 Alkyl or C2-C interrupted by one or more O 12 Alkyl, wherein the C1-C 12 Alkyl or interrupted C2-C 12 The alkyl group is unsubstituted or substituted by one or more C3-C7 cycloalkyl groups, OH, NCO or substituted by phenyl groups substituted by NCO; 12 Cycloalkyl; C2-C4 alkyl, unsubstituted or substituted by one or more C1-C4 alkyl, OH or C1-C4 alkoxy; 10 Alkenyl; unsubstituted or replaced by C1-C 12 Alkyl, C1-C 12 Alkoxy, NCO-substituted or C1-C 12 Alkyl-substituted C6-C 14 A group consisting of aromatic groups.

[0106] R 1f Each example of can be independently selected from the group consisting of C1-C4 alkyl, i.e., methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. Particularly preferred is R 1f Each instance of is selected from methyl and ethyl. Most preferably, R 1f Each instance of is methyl.

[0107] X f Selected from direct single bond, O, S, NR 3f More preferably, X f is selected from the group consisting of a direct single bond, O, -CH2CO2- and -CH2CH2CO2-. Still more preferably, X f is selected from the group consisting of a direct single bond, -CH2CO2- and -CH2CH2CO2-. Most preferably X f It is a direct single bond.

[0108] R 1f Choose from C1-C 40 Alkyl and C2-C8 interrupted by one or more O or C3-C8 cycloalkylene 40 Alkyl, wherein the C1-C 40 Alkyl or interrupted C2-C 40 The alkyl group may be unsubstituted or selected from OH and R 3f One or more groups are substituted;

[0109] Where R 3f yes

[0110] In some embodiments, there is no R 3f , which means that the structure according to formula (XI) has a single bisacylphosphine oxide moiety.

[0111] In such an embodiment, it is preferred that R 2f Choose from C1-C 20 Alkyl, -(CH2CH2O-) n CH3 and -(CH2CH2O-) n H, wherein n is an integer in the range of 1 to 20. Particularly preferred is R 2f It is C1-C 20 alkyl.

[0112] Particularly preferred are those in which X f is a single bond and R 2f It is C1-C 20 In such an embodiment, it is particularly preferred that R 1f Every instance of is a methyl group.

[0113] Similarly, where X f is O and R 2f Yes -(CH2CH2O-) n CH3 or -(CH2CH2O-) nThe embodiment of H is also particularly preferred. In such an embodiment, it is particularly preferred that R 1f Every instance of is a methyl group.

[0114] In other embodiments, there is R 3f In at least one example of this, it is meant that the structure according to formula (XI) has more than one bisacylphosphine oxide moiety.

[0115] Such an embodiment is preferably described by formula (XI) wherein R 1f Having a structure according to formula (XII):

[0116]

[0117] wherein each instance of M is independently selected from (CH2CH2O) and (CH2CH(CH3)O);

[0118] wherein each instance of Y is independently selected from hydrogen and C1-C4 alkyl;

[0119] wherein each instance of Z has the structure CH2(M 1 ) c R 2f ;

[0120] Among them, M 1 Each instance of is independently selected from (OCH2CH2) and (OCH(CH3)CH2)

[0121] Wherein a is an integer in the range of 0 to 15;

[0122] Wherein b is an integer in the range of 0 to 6;

[0123] wherein each instance of c is independently an integer in the range of 0 to 15;

[0124] wherein m is an integer in the range of 0 to 2; and

[0125] Where X f Each instance of is independently selected from the group consisting of -CH2CO2- and -CH2CH2CO2-.

[0126] Such structures are generally formed by combining a central polyol core with a plurality of BAPO-based carboxylic acid residues, optionally with ethylene glycol / propylene glycol spacers (i.e., units M and M 1 ) separates the central polyol core from the BAPO-based carboxylic acid residues.

[0127] Suitable polyol cores include glycerol, where b=0, m=1 and Y=H; trimethylolpropane, where b=1, m=1 and Y=ethyl; pentaerythritol, where b=1, m=0; neopentyl glycol, where b=1, m=2 and both instances of Y=methyl, ethylene glycol, where b=0, m=2 and both instances of Y=H; 1,6-hexanediol, where b=4, m=2 and both instances of Y=H.

[0128] Other suitable polyols include propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol. The skilled person will know which values ​​of b and m and the choice of Y correspond to these polyols.

[0129] Particularly preferred polyol cores are glycerol, where b=0, m=1 and Y=H, trimethylolpropane, where b=1, m=1, Y=ethyl, pentaerythritol, where b=1, m=0.

[0130] When using the glycerol core, R 2f Referred to as "optionally ethoxylated / propoxylated glycerol".

[0131] When using a trimethylolpropane nucleus, R 2f Referred to as "optionally ethoxylated / propoxylated trimethylolpropane".

[0132] When using the pentaerythritol core, R 2f Referred to as "optionally ethoxylated / propoxylated pentaerythritol".

[0133] When using the neopentyl glycol core, R 2f Referred to as "optionally ethoxylated / propoxylated neopentyl glycol".

[0134] When using an ethylene glycol core, R 2f Referred to as "optionally ethoxylated / propoxylated glycol".

[0135] When using the 1,6-hexanediol core, R 2f Referred to as "optionally ethoxylated / propoxylated 1,6-hexanediol".

[0136] It is particularly preferred that a is an integer in the range of 1 to 15 and each instance of c is an integer in the range of 1 to 15, wherein the sum of each instance of a and c is in the range of 3 to 20, more preferably in the range of 3 to 15, and most preferably in the range of 3 to 10.

[0137] Such embodiments are referred to as "ethoxylated / propoxylated polyols," wherein the polyol may be glycerol, trimethylolpropane, pentaerythritol, neopentyl glycol, ethylene glycol, or 1,6-hexanediol.

[0138] Particularly preferred is R 2f Choose from C1-C 20 Alkyl, -(CH2CH2O-) n CH3 and -(CH2CH2O-) n The group consisting of H, wherein n is an integer in the range of 1 to 20, ethoxylated / propoxylated glycerol, ethoxylated / propoxylated trimethylolpropane and ethoxylated / propoxylated pentaerythritol.

[0139] When R 2f It is C1-C 20 When alkyl, it is particularly preferred that R 2f It is C1-C 15 Alkyl, more preferably C1-C 12 alkyl.

[0140] It is particularly preferred that each of the one or more bisacylphosphine oxide photoinitiators each have a structure according to formula (XI).

[0141] In an alternative embodiment, at least one of the one or more bisacylphosphine oxide photoinitiators each has a structure according to Formula (XI), wherein R 1f Each instance of is independently selected from the group consisting of C1-C4 alkyl, X f is a direct single bond, and R 2f Choose from C6-C 14 Aryl, C1-C 20 Alkyl, -(CH2CH2O-) n CH3 and -(CH2CH2O-) n H, wherein n is an integer in the range of 1 to 20.

[0142] More preferably, R 2f Selected from C6-C 14 Aryl, most preferably phenyl.

[0143] In a particularly preferred embodiment, R 1f Each instance of is methyl, X f is a direct single bond, and R 2f It is phenyl.

[0144] Oxazole-based sensitizers

[0145] Another essential feature of the photoinitiator package according to the present invention is the presence of one or more oxazole-based sensitizers, each oxazole-based sensitizer having a structure according to formula (I)

[0146]

[0147] Where R 1 To R 4 Each independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 A group consisting of aromatic groups, to which R can be attached 1 and R 2 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 The aryl group is substituted with one or more substituents, and R 3 and R 4 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 substituted with one or more substituents from the group consisting of aryl; and

[0148] wherein A represents a linking group represented by any one of the following formulae (II) to (VI):

[0149]

[0150]

[0151] Each * represents the bonding position of A in each formula.

[0152] R 1 To R 4 Each independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 A group consisting of aromatic groups, to which R can be attached 1 and R 2 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 The aryl group is substituted with one or more substituents, and R 3 and R 4 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 The aryl group is substituted with one or more substituents.

[0153] In one embodiment, R1 To R 4 Each independently selected from hydrogen, C1-C6 alkyl and C6-C 10 A group consisting of aromatic groups.

[0154] In a particularly preferred embodiment, R 1 and R 3 Both are respectively related to R 2 and R 4 connected to form a 6-membered saturated or unsaturated ring, which may be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 The aryl group is substituted with one or more substituents.

[0155] In one embodiment of said particularly preferred embodiments, each 6-membered ring formed is aromatic, meaning that the oxazole-based sensitizer is a benzoxazole-based sensitizer having a structure according to formula (Ia):

[0156]

[0157] Where R 1g To R 8g Each independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 A group consisting of aromatic groups.

[0158] Preferably, R 1g To R 8g Each independently selected from hydrogen, C1-C6 alkyl and C6-C 10 A group consisting of aromatic groups.

[0159] In one embodiment, each of the one or more oxazole-based sensitizers has a structure according to Formula (Ia).

[0160] In other embodiments, at least one of the one or more oxazole-based sensitizers has a structure according to formula (Ia), while any remaining oxazole-based sensitizers in the photoinitiator package have other structures according to formula (I).

[0161] Particularly preferred compounds according to formula (I) include 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole), 2,2'-(vinylenebis-p-phenylene)bisbenzoxazole, 2,2'-(naphthalene-1,4-diyl)bis(benzoxazole), 2-[4-[2-[4-(benzoxazol-2-yl)phenyl]vinyl]phenyl]-5-methylbenzoxazole, 2,2'-(1,4-phenylene)bis[5-phenyl-oxazole].

[0162] Amines

[0163] Another essential feature of the photoinitiator package according to the present invention is the presence of one or more amines.

[0164] The present invention has found that the amines present in the Norrish Type-I photoinitiator based package in combination with an oxazole based sensitizer can significantly increase the cure rate, especially surface cure.

[0165] In the broadest sense, one or more amines according to the present invention can be any amine, and this any amine comprises aliphatic amines, alicyclic amines, aromatic amines, arylaliphatic amines, heterocyclic amines, oligomer amines or polymer amines.They can be primary amines, secondary amines or tertiary amines, for example, butylamine, dibutylamine, tributylamine, cyclohexylamine, benzyldimethylamine, dicyclohexylamine, N-phenylglycine, triethylamine, phenyl-diethanolamine, triethanolamine, piperidine, piperazine, morpholine, quinolone, esters of dimethylaminobenzoic acid and corresponding derivatives.In addition, amine-modified acrylates can be used.The example of such amine-modified acrylates comprises by reacting with the primary amine or secondary amine of 15 described in US 3,844,916, EP 280222, US 5,482,649 or US 5,734,002 and modified acrylates.

[0166] Also suitable polyfunctional amines and polymeric amine derivatives are Omnipol ASA from IGM Resins BV, Genopol AB-2 from Rahn AG, Speedcure 7040 from Lambson GmbH or those described in US 2013 / 0012611.

[0167] It will be understood by those skilled in the art that the term "amine" does not include amides or imides, regardless of whether the nitrogen of the amide / imide is bonded to an alkyl group. Likewise, ammonium salts are not amines.

[0168] It is preferred that the one or more amines are not Type-I or Type-II photoinitiators, such as the well-known aminoketone Type-I initiators. It is further preferred that the one or more amines are not optical brighteners, i.e. compounds that absorb light in the ultraviolet and violet regions of the EM spectrum and re-emit light in the blue region via fluorescence. It is therefore apparent that the only role of the amine in the photopolymerization package is to act as a synergist, enhancing the effectiveness of the one or more monoacyl or bisacylphosphine oxide photoinitiators and / or the one or more oxazole-based sensitizers.

[0169] Preferably, one or more of the amines has a so-called alpha hydrogen, ie a hydrogen bonded to a carbon which is directly bonded to the nitrogen of the amine. It is particularly preferred that this hydrogen is bonded to a sp 3 Hybridized carbon bonding. Thus, it is preferred that the amine have a nitrogen atom with a direct single bond to a methyl group (ie, CH3), a methylene group (ie, CH2 of CH2R), or a methanetriyl group (ie, CH of CHR2).

[0170] Without wishing to be bound by theory, it is believed that the alpha-hydrogen can be readily abstracted by free radicals to form stable alpha-amino free radicals which can play a role in increasing the cure rate, particularly by scavenging molecular oxygen, which can retard polymerization.

[0171] It is particularly preferred that the nitrogen atom is bonded to at least one alkyl group. It is further preferred that the nitrogen atom is bonded to at least two alkyl groups.

[0172] In a particularly preferred embodiment, the one or more amines are independently selected from the group consisting of amines having the formula NR A R B R C A group of amines, wherein R A and R B are independently selected from optionally substituted alkyl groups, and R C is selected from the group consisting of an optionally substituted alkyl group and an optionally substituted aryl group.

[0173] In the embodiment, the term "optionally substituted aryl group" does not include aryl groups having two or more substituents connected to form a fused ring system, such as quinoline, indole or coumarin. Likewise, the term "optionally substituted alkyl group" does not include substitutions that would result in the group no longer being considered an alkyl group, such as an acyl group (i.e., =O substitution at the first carbon atom of the alkyl chain).

[0174] Photoinitiator Package

[0175] The photoinitiator package according to the present invention comprises one or more monoacyl or bisacylphosphine oxide photoinitiators as described above, one or more oxazole-based sensitizers as described above and one or more amines as described above.

[0176] Preferably, the photoinitiator package comprises, more preferably consists of:

[0177] a) one or more mono- or bis-acylphosphine oxide photoinitiators in an amount in the range of 40 to 98.9 wt. %, more preferably in the range of 60 to 96.0 wt. %, most preferably in the range of 65 to 92.0 wt. % relative to the total weight of the photoinitiator package;

[0178] b) one or more oxazole-based sensitizers in an amount ranging from 0.1 to 50 wt. %, more preferably ranging from 1.0 to 37 wt. %, most preferably ranging from 3.0 to 30 wt. % relative to the total weight of the photoinitiator package; and

[0179] c) one or more amines in an amount ranging from 1.0 to 45 wt. %, more preferably ranging from 3.0 to 35 wt. %, most preferably ranging from 5.0 to 30 wt. %, relative to the total weight of the photoinitiator package.

[0180] In another embodiment, the photoinitiator package comprises, more preferably consists of:

[0181] a) one or more monoacyl or bisacylphosphine oxide photoinitiators in an amount ranging from 40 to 98.9 wt % relative to the total weight of the photoinitiator package;

[0182] b) one or more oxazole-based sensitizers in an amount ranging from 0.1 to 50 wt. % relative to the total weight of the photoinitiator package; and

[0183] c) one or more amines in an amount ranging from 1.0 to 45 wt. % relative to the total weight of the photoinitiator package.

[0184] In another embodiment, the photoinitiator package comprises, more preferably consists of:

[0185] a) one or more monoacyl or bisacylphosphine oxide photoinitiators in an amount ranging from 60 to 96.0 wt % relative to the total weight of the photoinitiator package;

[0186] b) one or more oxazole-based sensitizers in an amount ranging from 1.0 to 37 wt % relative to the total weight of the photoinitiator package; and

[0187] c) one or more amines in an amount ranging from 3.0 to 35 wt. % relative to the total weight of the photoinitiator package.

[0188] In yet another embodiment, the photoinitiator package comprises, more preferably consists of:

[0189] a) one or more monoacyl or bisacylphosphine oxide photoinitiators in an amount ranging from 65 to 92.0 wt % relative to the total weight of the photoinitiator package;

[0190] b) one or more oxazole-based sensitizers in an amount ranging from 3.0 to 30 wt. % relative to the total weight of the photoinitiator package; and

[0191] c) one or more amines in an amount ranging from 5.0 to 30 wt. % relative to the total weight of the photoinitiator package.

[0192] If additional components are present besides the one or more monoacyl or bisacylphosphine oxide photoinitiators, the one or more oxazole-based sensitizers and the one or more amines, they are preferably additional Type-I photoinitiators.

[0193] It is particularly preferred that the only photoinitiator present in the photoinitiator package is a Norrish Type-I photoinitiator or a cationic photoinitiator.

[0194] It is further preferred that the only photoinitiator present in the photoinitiator package is a Norrish Type-I photoinitiator.

[0195] Additionally or alternatively, further fluorescent brightener sensitizers may be present.

[0196] As will be understood by those skilled in the art, the term "additional fluorescent whitening agent sensitizers" means that these additional sensitizers have structures other than the one or more oxazole-based sensitizers.

[0197] As will be understood by those skilled in the art, the term "sensitizer" in "one or more fluorescent brightener sensitizers" explains the purpose of the fluorescent brightener in the photoinitiator package and does not limit the choice of fluorescent brighteners that may be employed.

[0198] Furthermore, it will be clear to those skilled in the art that fluorescent whitening agents are chemical compounds that absorb light in the ultraviolet and violet regions of the EM spectrum and re-emit light in the blue region via fluorescence.

[0199] Therefore, preferably, the photoinitiator package comprises one or more bisacylphosphine oxide photoinitiators, one or more oxazole-based sensitizers, one or more amines, optionally one or more additional Type-I photoinitiators and optionally one or more additional fluorescent whitening agent sensitizers, and more preferably consists of one or more bisacylphosphine oxide photoinitiators, one or more oxazole-based sensitizers, one or more amines, optionally one or more additional Type-I photoinitiators and optionally one or more additional fluorescent whitening agent sensitizers.

[0200] Therefore, the photoinitiator package preferably consists of:

[0201] a) one or more mono- or bis-acylphosphine oxide photoinitiators in an amount in the range of 40 to 98.9 wt. %, more preferably in the range of 60 to 96.0 wt. %, most preferably in the range of 65 to 92.0 wt. % relative to the total weight of the photoinitiator package;

[0202] b) one or more oxazole-based sensitizers in an amount ranging from 0.1 to 50 wt. %, more preferably ranging from 1.0 to 37 wt. %, most preferably ranging from 3.0 to 30 wt. % relative to the total weight of the photoinitiator package;

[0203] c) one or more amines in an amount ranging from 1.0 to 45 wt. %, more preferably ranging from 3.0 to 35 wt. %, most preferably ranging from 5.0 to 30 wt. % relative to the total weight of the photoinitiator package;

[0204] d) an additional Type-I initiator in an amount in the range of 0.0 to 58.9 wt %, more preferably in the range of 0 to 36.0 wt %, most preferably in the range of 0.0 to 27.0 wt %; and

[0205] e) an additional fluorescent whitening agent sensitizer in an amount in the range of 0.0 to 58.9 wt%, more preferably in the range of 0 to 36.0 wt%, most preferably in the range of 0.0 to 27.0 wt%.

[0206] Photopolymerizable composition

[0207] In a second aspect, the present invention also relates to a photopolymerizable composition.

[0208] In the broadest sense, the photopolymerizable composition comprises or consists of:

[0209] a) one or more ethylenically unsaturated free-radically polymerizable compounds;

[0210] b) A photoinitiator package according to the first aspect.

[0211] Preferably, the photopolymerizable composition comprises or consists of:

[0212] a) one or more ethylenically unsaturated free-radically polymerizable compounds in an amount ranging from 30 to 99.0 wt. %, more preferably ranging from 50 to 95.0 wt. %, most preferably ranging from 70 to 90 wt. % relative to the total weight of the photopolymerizable composition;

[0213] b) a photoinitiator package according to the first aspect in an amount in the range of 0.5 to 50 wt.-%, more preferably in the range of 0.8 to 40 wt.-%, most preferably in the range of 1.0 to 30 wt.-% relative to the total weight of the photopolymerizable composition.

[0214] In addition to the one or more ethylenically unsaturated free-radically polymerizable compounds according to the first aspect and the photoinitiator package, the photopolymerizable composition may comprise further components, as is well known to those skilled in the art.

[0215] Suitable further components include photosensitizers, further photoinitiators, pigments, binders and customary additives.

[0216] Thus, the photopolymerizable composition comprises, more preferably consists of

[0217] a) one or more ethylenically unsaturated free-radically polymerizable compounds in an amount ranging from 30 to 99.0 wt. %, more preferably ranging from 50 to 95.0 wt. %, most preferably ranging from 70 to 90 wt. % relative to the total weight of the photopolymerizable composition;

[0218] b) a photoinitiator package according to the first aspect in an amount in the range of 0.5 to 50 wt.-%, more preferably in the range of 0.8 to 40 wt.-%, most preferably in the range of 1.0 to 30 wt.-% relative to the total weight of the photopolymerizable composition;

[0219] c) optionally one or more additional photoinitiators, one or more photosensitizers and / or one or more co-initiators in an amount in the range of 0.5 to 30 wt. %, more preferably in the range of 0.8 to 20 wt. %, most preferably in the range of 1.0 to 15 wt. %;

[0220] d) optionally one or more pigments in an amount ranging from 0.1 to 30 wt. %, more preferably ranging from 1.0 to 25 wt. %, most preferably ranging from 10 to 20 wt. % relative to the total weight of the photopolymerizable composition;

[0221] e) optionally one or more binders in an amount ranging from 5.0 to 60 wt. %, more preferably ranging from 8.0 to 50 wt. %, most preferably ranging from 10 to 40 wt. % relative to the total weight of the photopolymerizable composition; and

[0222] f) optionally one or more additives in an amount ranging from 0.01 to 10 wt. %, more preferably ranging from 0.01 to 8.0 wt. %, most preferably ranging from 0.01 to 5.0 wt. %, relative to the total weight of the photopolymerizable composition.

[0223] Additionally, the photopolymerizable composition may be formulated as a composition further comprising water and / or a solvent such as an organic solvent.

[0224] Preferably, no further photoinitiators, photosensitizers or co-initiators are present other than those forming part of the photoinitiator package. In other words, all components contributing to the photopolymerization properties of the photoinitiator are preferably comprised in the photoinitiator package, as defined above and below.

[0225] The choice of one or more ethylenically unsaturated free radical polymerizable compounds is not particularly limited. The polymerizable compounds may contain one or more olefinic double bonds. They may be low molecular weight (monomers) or high molecular weight (oligomers) compounds.

[0226] Examples of suitable low molecular weight polymerizable compounds (monomer compounds) having one double bond are alkyl acrylates or hydroxyalkyl acrylates or methacrylates, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate or isobornyl acrylate; and methyl methacrylate or ethyl methacrylate. Another example 5 is a resin modified with silicon or fluorine, such as silicone acrylate. Other examples of these polymerizable compounds are acrylonitrile, acrylamide, methacrylamide, N-substituted (meth)acrylamide, styrene, alkyl styrene and halogenated styrene, vinyl esters (such as vinyl acetate), vinyl ethers (such as isobutyl vinyl ether), N-vinyl pyrrolidone, vinyl chloride or vinylidene chloride.

[0227] Examples of polymerizable compounds having more than one double bond are ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, bisphenol A diacrylate, 4,4′-bis-(2-acryloyloxyethoxy)-diphenylpropane, trimethylolpropane triacrylate, pentaerythritol triacrylate or tetraacrylate, vinyl acrylate, divinylbenzene, divinyl succinate, diallyl phthalate, triallyl phosphate, triallyl isocyanurate or tris-(2-acryloylethyl) isocyanurate.

[0228] Examples of high molecular weight (oligomeric) polyunsaturated compounds are acrylated epoxy resins, acrylated polyesters or polyesters containing vinyl ethers or polyesters containing epoxy groups, acrylated polyurethanes or acrylated polyethers.

[0229] Another example of an unsaturated oligomer is an unsaturated polyester resin, which is typically prepared from maleic acid, phthalic acid and one or more diols and has a molecular weight of about 500 to 3,000 Da. Such unsaturated oligomers may also be referred to as prepolymers.

[0230] Examples of polymerizable compounds particularly suitable for the practice of the present invention are esters of ethylenically unsaturated carboxylic acids and polyols or polyepoxides, and polymers containing ethylenically unsaturated groups in the chain or in side groups (e.g. unsaturated polyesters, polyamides and polyurethanes and copolymers thereof), alkyl resins, polybutadiene and butadiene copolymers, polyisoprene and isoprene copolymers, polymers and copolymers having (meth)acrylic groups in side chains, and mixtures thereof.

[0231] Illustrative examples of unsaturated carboxylic acids or anhydrides used to prepare the above esters are acrylic acid, methacrylic acid, maleic anhydride, crotonic acid, itaconic acid, cinnamic acid and unsaturated fatty acids such as linolenic acid and oleic acid. Acrylic acid and methacrylic acid are preferred.

[0232] Examples of polyols that can also be esterified are aromatic polyols and aliphatic polyols and alicyclic polyols, preferably aliphatic polyols and alicyclic polyols. Aromatic polyols are, for example, hydroquinone, 4,4'-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane, and novolacs and resols.

[0233] Polyepoxides which can be esterified include those based on the polyols, in particular the reaction products between aromatic polyols and epichlorohydrin. Also suitable as polyols are polymers and copolymers containing hydroxyl groups in the polymer chain or in the side groups, for example polyvinyl alcohol and its copolymers or polyhydroxyalkyl methacrylates or their copolymers. Other suitable polyols are oligoesters with hydroxyl end groups.

[0234] Examples of aliphatic polyols and alicyclic polyols include alkylene glycols preferably containing 2 to 12 carbon atoms, such as ethylene glycol, 1,2-propylene glycol or 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol or 1,4-butylene glycol, pentanediol, hexanediol, octanediol, dodecanediol, diethylene glycol, triethylene glycol, polyethylene glycol preferably having a molecular weight of 200 to 1,500 Da, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol or 1,4-cyclohexanediol, 1,4-dihydroxymethylcyclohexane, glycerol, tris(β-hydroxy-ethyl)amine, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol and sorbitol.

[0235] Further suitable ethylenically unsaturated compounds are unsaturated polyamides obtained from unsaturated carboxylic acids and aromatic, aliphatic and cycloaliphatic polyamines, preferably having 2 to 6, preferably 2 to 4, amino groups. Examples of such polyamines are: ethylenediamine, 1,2- or 1,3-propylenediamine, 1,2-, 1,3- or 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexanediamine, octanediamine, dodecanediamine, 1,4-diaminocyclohexane, isophoronediamine, phenylenediamine, diphenylenediamine, di-(β-aminoethyl)ether, diethylenetriamine, triethylenetetramine and di(β-aminoethoxy)-ethane and di(β-aminopropoxy)-ethane. Other suitable polyamines are polymers and copolymers which may contain additional amino groups in the side chains, and oligoamides containing amino end groups.

[0236] Specific examples of such unsaturated polyamides are methylenebisacrylamide, 1,6-hexamethylene bisacrylamide, diethylenetriaminetrimethylacrylamide, bis(methacrylamidopropoxy)ethane and N-[(β-hydroxyethoxy)ethyl]-acrylamide.

[0237] Unsaturated polyurethanes are also suitable as polymerizable compounds for carrying out the present invention, for example those derived from saturated or unsaturated diisocyanates and unsaturated or saturated diols.

[0238] Polybutadiene and polyisoprene and copolymers thereof may also be used.

[0239] Suitable polymerizable compounds include, for example, olefins (such as ethylene, propylene, butene and hexene), (meth)acrylates, acrylonitrile, styrene and vinyl chloride. Polymers having unsaturated (meth)acrylate groups on side chains may also be used as one or more ethylenically unsaturated free-radically polymerizable compounds. They may generally be 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)acrylate; and homopolymers and copolymers of (meth)acrylates which have been esterified with hydroxyalkyl (meth)acrylates.

[0240] Examples of photosensitizers are those commonly used in the art, terphenyls, styryl ketones and 3-(aroylmethylene)-thiazolines, and also eosin, rhodamine and erythrosine dyes.

[0241] It was observed that the above-mentioned photosensitizers increased the activity of one or more bisacylphosphine oxide photoinitiators without shortening the shelf life of the composition. In addition, such compositions have the particular advantage that the appropriate choice of photosensitizer allows the spectral sensitivity of the photoinitiator package to be shifted to any desired wavelength region. A person skilled in the art is able to select a suitable photosensitizer to make the photoinitiator package functional at any desired wavelength region.

[0242] Examples of other suitable photoinitiators are acetophenone, acetophenone derivatives, dialkoxyacetophenones, α-hydroxyketones, α-aminoketones, benzoin alkyl ethers and benzil ketals (e.g. benzil dimethyl ketal), acylphosphine photoinitiators (which may be selected from monoacylphosphine oxides, bisacylphosphine oxides, triacylphosphine oxides and multifunctional monoacylphosphine oxides or bisacylphosphine oxides), halomethyltriazines, hexaarylbisimidazole / coinitiator systems (e.g. a combination of o-chlorohexaphenylbisimidazole and 2-mercaptobenzothiazole), ferrocenium compounds or titanocenes (e.g. dicyclopentadienyl-bis(2,6-difluoro-3-pyrrolophenyl)titanium), O-acyloxime ester photoinitiators.

[0243] Examples of α-hydroxyketones and α-aminoketones are 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-ethyl-propane-1-one), 2-hydroxy-1-{4-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one -(2-hydroxy-2-methyl-propionyl)-phenoxy-phenyl}-2-methyl-propan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and (2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone).

[0244] Examples of acylphosphine photoinitiators include, but are not limited to, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-(2,4-dipentyloxyphenyl), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate, phenyl(2,4,6-trimethylbenzoyl)phosphinic acid, ethoxylated triester of glycerol (from IGM Resins B.V. TP).

[0245] Examples of halomethyltriazine-based photoinitiators are 2-[2-(4-methoxy-phenyl)-vinyl]-4,6-bis-trichloromethyl[1,3,5]triazine, 2-(4-methoxy-phenyl)-4,6-bis-trichloromethyl[1,3,5]triazine, 2-(3,4-dimethoxyphenyl)-4,6-bis-trichloromethyl[1,3,5]triazine, 2-methyl-4,6-bis-trichloromethyl[1,3,5]triazine.

[0246] When the photopolymerizable composition according to the invention is used in a hybrid system (in this context, a mixture of free radical and cationic curing systems), cationic photoinitiators can also be used as additional photoinitiators. Examples of suitable cationic photoinitiators are aromatic sulfonium salts, phosphonium salts or iodonium salts, as described, for example, in US 4,950,581, or cyclopentadienyl arene-iron (II) complex salts, as described, for example, in GB 2348644, US 4,450,598, US 4,136,055, WO 00 / 10972 and WO 00 / 26219, for example (η 6 -isopropylbenzene)(η 5-cyclopentadienyl)iron(II) hexafluorophosphate or oxime-based photolatent acids.

[0247] Any pigment known to those skilled in the art may be used in the photopolymerizable composition.

[0248] Depending on the intended use, both inorganic and organic pigments can be used. Such additives are well known to those skilled in the art; some examples are carbon black, iron oxides (such as yellow iron oxide, red iron oxide), chrome yellow, chrome green, nickel titanium yellow, ultramarine blue, cobalt blue, bismuth vanadate, cadmium yellow and cadmium red. Examples of organic pigments are monoazo pigments or disazo pigments, as well as their metal complexes, phthalocyanine pigments, polycyclic pigments, such as perylene, anthraquinone, thioindigo, quinacridone or triphenylmethane pigments, as well as diketo-pyrrolo-pyrrole, isoindolinone, such as tetrachloroisoindolinone, isoindolinone, dioxazine, benzimidazolone and quinophthalone pigments. The pigments can be used alone or in combination in the formulation.

[0249] When the ethylenically unsaturated free radical polymerizable compound is a liquid or viscous substance, it is particularly advantageous to add a binder. The choice of binder is based on the field of use and its required properties, such as developability in aqueous and organic solvent systems, adhesion to substrates and sensitivity to oxygen. Suitable binders are, for example, polymers with a weight average molecular weight (Mw) of about 5,000Da to 2,000,000Da, preferably 10,000Da to 1,000,000Da. Illustrative examples are: homopolymers and copolymers of acrylates and methacrylates, for example copolymers of methyl methacrylate / ethyl acrylate / methacrylic acid, poly(alkyl methacrylates), poly(alkyl acrylates); cellulose esters and ethers, such as cellulose acetate, cellulose acetate butyrate, methyl cellulose, ethyl cellulose, polyvinyl butyral, polyvinyl formal, cyclized rubbers, polyethers (such as polyethylene oxide, polypropylene oxide, polytetramethylene oxide), polystyrene, polycarbonate, polyurethane, chlorinated polyolefins (e.g., polyvinyl chloride, copolymers of vinyl chloride / vinylidene chloride, copolymers of vinylidene chloride with acrylonitrile, methyl methacrylate and vinyl acetate), polyvinyl acetate, copoly(ethylene / vinyl acetate), polymers (such as polycaprolactam and poly(hexamethylene adipamide)), polyesters (such as poly(ethylene terephthalate) and poly(hexamethylene succinate)).

[0250] The choice of additives depends on the application area in question and the properties desired in that area. Typical additives include thermal initiators, stabilizers, light stabilizers, fillers, colorants, antistatic agents, wetting agents, flow improvers and adhesion enhancers.

[0251] For example, in particular in the case of pigmented compositions, the composition may also contain as additional additives thermal initiators, compounds which form free radicals upon heating, for example azo compounds such as 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), triazenes, diazosulfides (also known as benzothiadiazoles), pentazadienes or peroxy compounds, for example hydroperoxides or peroxycarbonates, for example tert-butyl hydroperoxide, as described, for example, in EP 245 639.

[0252] Suitable stabilizers are, for example, thermal inhibitors such as hydroquinone, hydroquinone derivatives, p-methoxyphenol, β-naphthol or hindered phenols, for example 2,6-di(tert-butyl)-p-cresol, which prevent premature polymerization. In order to improve the dark storage stability, for example copper compounds (such as copper naphthenate, copper stearate or copper octoate), phosphorus compounds (such as triphenylphosphine, tributylphosphine, triethyl phosphite, triphenyl phosphite or tribenzyl phosphite), quaternary ammonium compounds (such as tetramethylammonium chloride or benzyltrimethylammonium chloride) or hydroxylamine derivatives, such as N,N-diethylhydroxylamine, can be used. For the purpose of excluding atmospheric oxygen during polymerization, paraffin wax or similar waxy substances that are insoluble in the polymer can be added, which migrate to the surface at the beginning of polymerization and form a transparent surface layer that prevents air from entering.

[0253] Light stabilizers may also be added, such as UV absorbers, for example of the hydroxyphenylbenzotriazole, hydroxyphenylbenzophenone, oxalic acid amide or hydroxyphenyl-s-triazine type. Such components may be used on their own or in mixtures, with or without the use of sterically hindered amines (HALS).

[0254] All alternative positions and preferred embodiments of the photoinitiator package described above or below are applicable mutatis mutandis to the photopolymerizable composition according to the present invention.

[0255] method

[0256] In a third aspect, the present invention relates to a method for photocuring photopolymerizable compositions, coatings, adhesives and inks, the method comprising the following steps in the given order:

[0257] a) coating or printing the photopolymerizable composition according to the second aspect onto a substrate, and

[0258] b) photopolymerizing the coated or printed composition on the substrate using a light source.

[0259] Preferably, the light source operates in the near-UV or visible range of the EM spectrum.

[0260] All alternative positions and preferred embodiments of the photoinitiator packages and photopolymerizable compositions described above or below are applicable mutatis mutandis to the methods for photocuring photopolymerizable compositions, coatings, adhesives and inks according to the present invention.

[0261] use

[0262] In a fourth aspect, the present invention relates to the use of the photoinitiator package according to the first aspect in the production of printing inks, screen printing inks, gravure printing inks, solder masks, etching offset inks, flexographic printing inks, gravure inks, inkjet inks, resist materials, insulators, sealants, image recording materials, solder masks, passivation layers, protective coatings, 3D printed objects and molds, holographic applications, optical fiber coatings, waveguides and lenses, overprint varnishes, wood, vinyl, metal and plastic coatings.

[0263] All alternative positions and preferred embodiments of the photoinitiator package described above or below are applicable mutatis mutandis to the use according to the present invention.

[0264] In a final aspect, the present invention relates to the use of a combination of one or more amines and one or more oxazole-based sensitizers for increasing the surface cure rate of a photopolymerizable composition comprising one or more Norrish Type-I photoinitiators.

[0265] It is particularly preferred that the one or more Norrish Type-I photoinitiators are selected from monoacyl or bisacylphosphine oxide photoinitiators.

[0266] All alternative positions and preferred embodiments of the one or more monoacyl or bisacylphosphine oxide photoinitiators, oxazole-based sensitizers and / or amines described in the first aspect are applicable mutatis mutandis to the use in the present aspect.

[0267] Furthermore, it is preferred that the photopolymerizable composition is a photopolymerizable composition according to the second aspect. All alternatives and preferred embodiments of the photopolymerizable composition of the second aspect are applicable mutatis mutandis to the use according to the present aspect.

[0268] It is particularly preferred that the combination of one or more amines and one or more oxazole-based sensitizers achieve a greater increase in surface cure rate.

[0269] In one embodiment, the effect of "increasing the surface cure rate" is achieved if the surface cure rate (given in tack-free m / min) in the presence of a combination of one or more amines and one or more oxazole-based sensitizers is at least 1.5 times, more preferably at least 2.0 times, more preferably at least 3.0 times, and most preferably at least 5.0 times the surface cure rate in the absence of a combination of one or more amines and one or more oxazole-based sensitizers.

[0270] Example

[0271] A. Determination Method

[0272] Tack-free measurement: Tack-free refers to the coating state in which the coating is completely cured on the surface. The evaluation is as follows: The formulation is applied to a varnished cardboard at a thickness of 12 micrometers using a bar-coater and photopolymerized under a light source. The operator's thumb is then brought into contact with the coating with slight pressure, and if no fingerprints / traces are left on the surface, the coating has been completely cured. The maximum speed (m / min) at which no fingerprints / traces are left on the surface is given as the value of tack-free. A higher maximum speed corresponds to a higher reactivity.

[0273] B. Experiment

[0274] 1. Materials used

[0275] The following commercially available compounds were used in the preparation of the present invention formulations and comparative formulations:

[0276] PI-1: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, CAS#: 162881-26-7, can be used as

[0277] Omnirad 819 was commercially available from IGM Group BV (The Netherlands).

[0278] PI-2: Bis(2,4,6-trimethylbenzoyl)octylphosphine oxide prepared as in US Pat. No. 5,534,559 A.

[0279] S: 2,5-bis(5-tert-butyl-1,3-benzoxazolyl)thiophene, CAS#: 7128-64-5, can be used as

[0280] Omnistab OB was commercially available from IGM Group BV (The Netherlands).

[0281] A1: 1H-Aza-1-propionic acid, hexahydro-2,2-bis[[(1-oxo-2-propen-1-yl)oxy]methyl]butyl ester, commercially available as Photomer 4250 from IGM Group BV (The Netherlands).

[0282] A2: Triethanolamine, CAS#: 102-71-6, commercially available from Merck KGaA (Germany).

[0283] A3: Poly(ethylene glycol) bis(p-dimethylaminobenzoate), CAS#: 71512-90-8, commercially available as Omnipol ASA from IGM Group BV (The Netherlands).

[0284] Mi: 40:30:30 photopolymerizable monomer blend of M1, M2 and M3.

[0285] M-ii: 50:15:15:20 photopolymerizable monomer blend of M1, M4, M5 and M6.

[0286] M-iii: 50:25:25 photopolymerizable monomer blend of M1, M4 and M6.

[0287] M1: Bisphenol Y epoxy diacrylate, CAS#: 55818-57-0, available as Photomer 3016

[0288] Commercially available from IGM Group BV (Netherlands).

[0289] M2 Glyceryl [4PO] triacrylate, CAS#: 52408-84-1, available as Photomer 4094 from

[0290] Commercially available from IGM Group BV (Netherlands).

[0291] M3 trimethylolpropane triacrylate, CAS#: 15625-89-5, can be used as Photomer 4006 from

[0292] Commercially available from IGM Group BV (Netherlands).

[0293] M4 is a blend of pentaerythritol triacrylate and pentaerythritol tetraacrylate, CAS#: 3524-68-3 and 4986-89-4, commercially available as Photomer 4335 from IGM Group BV (The Netherlands).

[0294] M5 dipentaerythritol penta / hexaacrylate, CAS#: 1384855-91-7, is commercially available as Photomer 4600 from IGM Group BV (The Netherlands).

[0295] M6 pentaerythritol [5EO] tetraacrylate, CAS#: 51728-26-8, is commercially available as Photomer 4172 from IGM Group BV (The Netherlands).

[0296] 2. Preparation (Photopolymerizable Composition)

[0297] The following inventive and comparative formulations were used in the surface curing evaluation, wherein the amount of each component is given in weight percent (wt%). The formulations were prepared by adding the photoinitiator, sensitizer and amine at the concentrations shown in Table 1 to the photopolymerizable monomer blend M at room temperature. The formulations were stirred at 60° C. for 2 hours and, after cooling at room temperature, were applied to varnished paperboard using a bar coater at a thickness of 12 microns. Thereafter, the formulations were photopolymerized using a light source (Table 2):

[0298] Table 1a: Formulations of the Inventive and Comparative Formulations Using Monomer Blend Mi

[0299]

[0300] Table 1b: Formulations of the Inventive and Comparative Formulations (Amine vs. Amide) Using Monomer Blend M-ii and Control Experiments

[0301]

[0302] 3. Surface photocuring evaluation

[0303] According to the test method provided in the determination method, different light sources were used (the values ​​in Table 2 correspond to the maximum tack-free speed in m / min) to evaluate the surface photocurability of the formulations of the present invention and the comparative formulations:

[0304] Table 2a: Performance of Mi formulations in surface photocuring

[0305]

[0306] *n / m = not measured

[0307] Lamp 1: UV Hg lamp with an intensity of 120 W / cm2 at a distance of 8 cm.

[0308] Lamp 2: UV Hg lamp with an intensity of 85 W / cm2 and a distance of 8 cm.

[0309] Lamp 3: wavelength 395nm and intensity 4W / cm 2 The UV LED light is at a distance of 0.5cm.

[0310] Light 4: wavelength 365nm and intensity 4W / cm 2 The UV LED light is at a distance of 0.5cm.

[0311] Lamp 5: wavelength 278nm and intensity 4W / cm 2 The UV LED light is at a distance of 0.5cm.

[0312] Table 2b: Performance of M-ii and control formulations in surface photocuring

[0313]

[0314] Lamp 1: UV Hg lamp with an intensity of 120 W / cm2 at a distance of 8 cm.

[0315] Lamp 2: UV Hg lamp with an intensity of 85 W / cm2 and a distance of 8 cm.

[0316] Lamp 6: wavelength 395nm and intensity 16W / cm 2 The UV LED light is at a distance of 0.5cm.

[0317] Lamp 7: wavelength 365nm and intensity 16W / cm 2 The UV LED light is at a distance of 0.5cm.

[0318] From the data in Table 2, it can be seen that the use of oxazole-based sensitizer S in combination with photoinitiators PI-1 and PI-2 improves the cure rate for each lamp used (CE3 / CE4 vs. CE1, CE6 vs. CE5); however, it is the synergistic use of sensitizers and amines that provides the greatest improvement. Comparing CE2 with CE1 shows that amines alone do have an effect on the cure rate of Type-I photoinitiators; however, when both amines and sensitizers are used, the effect is generally greater than that predicted by a simple additive effect (i.e., the amine and sensitizer act synergistically).

[0319] While results with lamp 1 are barely obtainable, as the activity is generally above the limit of the test, lamps 2 to 5 demonstrate that the addition of A1 leads to a significant improvement, with values ​​generally being about 20 m / min higher than in the examples without amine (IE1 vs. CE3).

[0320] Similar improvements were seen when using PI-2 (ie, IE5 vs. CE6), with good surface cure seen in all five lamps.

[0321] In addition, the use of amines allows for a significant reduction in the amount of sensitizer, with only 1.5 wt% sensitizer being used in CE4 and IE2 to IE4. A1 shows a significant improvement (IE2 vs. CE4), with the activity of the sensitizer / amine combination (1.5 wt% and 5 wt%) being significantly higher than 10 wt% of the individual sensitizers (IE2 vs. CE3). Although IE3 and IE4 are slightly less active than IE2, they are still very valuable sensitizer / amine combinations, especially considering the lower cost of A2 relative to more complex amines.

[0322] Comparison of IE6 with CE7 to CE9 further reinforces the conclusions drawn from Table 2a, although IE7 demonstrates that while amines improve surface cure relative to CE10, amides (such as acryloylmorpholine) have a detrimental effect (CE11), performing not only worse than amines, but also worse than CE10 without an amine / amide.

Claims

1. A photoinitiator package comprising: a) one or more monoacyl or bisacylphosphine oxide photoinitiators, b) one or more oxazole-based sensitizers, each oxazole-based sensitizer having a structure according to formula (I): Where R 1 To R 4 Each independently selected from hydrogen, C 1 -C 10 Alkyl and C 6 -C 14 A group consisting of aromatic groups, to which R can be attached 1 and R 2 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C 1 -C 10 Alkyl and C 6 -C 14 The aryl group is substituted with one or more substituents, and R 3 and R 4 To form a 6-membered saturated or unsaturated ring, the ring can be selected from hydrogen, C 1 -C 10 Alkyl and C 6 -C 14 substituted with one or more substituents from the group consisting of aryl; and wherein A represents a linking group represented by any one of the following formulae (II) to (VI): wherein each * represents a bonding position of A in each formula; and c) One or more amines.

2. The photoinitiator package of claim 1, wherein each of the one or more amines has a nitrogen atom having a direct single bond to a methyl group, a methylene group, or a methanetriyl group.

3. The photoinitiator package according to claim 1 or 2, wherein at least one of the one or more bisacylphosphine oxide photoinitiators has a structure according to any one of formulas (VII) to (X): Where R 1a , R 2a , R 3a , R 1b , R 2b and R 3b Each instance of is independently selected from C 1 -C 4 Alkyl, C 1 -C 4 a group consisting of alkoxy or halogen; Wherein X is selected from direct single bond, O, S, NR 5a 、-CH 2 CO 2 -and-CH 2 CH 2 CO 2 - The groups formed; Where R 4a Selected from hydrogen, (CO)R 6a 、(CO)OR 6a 、(CO)NR 5a R 6a 、(SO 2 )R 6a 、[Si(R 7a )(R 8a )] m -Si(R 7a )(R 8a )(R 9a )、[Si(R 7a )(R 8a )O] m -Si(R 7a )(R 8a )(R 9a ); or Where R 4a It is C 1 -C 28 Alkyl or one or more O, NR 5a , S, (CO), (CO)O or SO 2 Interrupted C 2 -C 28 Alkyl, wherein the C 1 -C 28 Alkyl or interrupted C 2 -C 28 The alkyl group is unsubstituted or is selected from OH, C 6 -C 14 Aryl, [Si(R 7a )(R 8a )] m -Si(R 7a )(R 8a )(R 9a )、[Si(R 7a )(R 8a )-O] m -Si(R 7a )(R 8a )(R 9a )、N(R 5a ) 2 , 2-oxirane, unsubstituted or replaced by C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy substituted or OH substituted C 3 -C 12 Cycloalkyl, substituted by one or more O, NR 5a or S interrupted C 3 -C 12 Cycloalkyl and interrupted C 3 -C 12 Cycloalkyl is unsubstituted or substituted with C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy substituted or substituted by OH, and unsubstituted or substituted by C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy substituted or OH substituted C 6 -C 14 substituted with one or more substituents from the group consisting of aryl; or Where R 4a is unsubstituted or replaced by one or more C 1 -C 12 Alkyl, C interrupted by one or more O 2 -C 20 Alkyl, C 1 -C 12 -C substituted with alkoxy or OH 6 -C 10 aryl; or in ,exist X is NR 5a In the case of R 4a With R 5a Together with the N-atom, it forms a 5- or 6-membered saturated ring, which is uninterrupted or terminated by O or NR 5a interrupted, and the uninterrupted or interrupted ring is unsubstituted or replaced by one or more C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy substituted or substituted by OH; or Where R 4a Selected from the group consisting of structures (A) to (G): Where R 4a All options can be further selected from OH and R 17a One or more groups are substituted; Where R 17a yes Where A is PF 6 , SbF 6 , AsF 6 or B(C 6 F 5 ) 4 ; Where R 5a is hydrogen, (CO)R 6a , phenyl, C 1 -C 12 Alkyl, C interrupted by one or more O 2 -C 12 Alkyl, unsubstituted or substituted with one or more C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy, OH or NCO substituted C 3 -C 12 Cycloalkyl, wherein the C 1 -C 12 Alkyl or interrupted C 2 -C 12 Alkyl is unsubstituted or substituted with one or more C 3 -C 7 Cycloalkyl, OH substituted or substituted by NCO; Where R 6a It is C 1 -C 12 Alkyl or C interrupted by one or more O 2 -C 12 Alkyl, wherein the C 1 -C 12 Alkyl or interrupted C 2 -C 12 Alkyl is unsubstituted or substituted with one or more C 3 -C 7 Cycloalkyl, OH, NCO substituted or phenyl substituted by NCO; or Where R 6a is unsubstituted or replaced by one or more C 1 -C 4 Alkyl, OH or C 1 -C 4 Alkoxy substituted C 3 -C 12 Cycloalkyl or C 2 -C 10 alkenyl; or Where R 6a is unsubstituted or replaced by C 1 -C 12 Alkyl, C 1 -C 12 Alkoxy, NCO-substituted or NCO-substituted C 1 -C 12 Alkyl substituted C 6 -C 14 aryl; or If there is a group N(R 5a ) 2 , then R 5a An example of (CO)R 6a , where R 5a and R 6a Another example is to form a 5- or 6-membered ring with the N and CO moieties, the 5- or 6-membered ring being uninterrupted or being replaced by O or NR 5a interrupted, and the uninterrupted or interrupted ring is unsubstituted or replaced by one or more C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy substituted or substituted by OH; Where R 7a , R 8a and R 9a Each independently selected from C 1 -C 4 Alkyl, C 6 -C 14 Aryl or C 1 -C 4 A group consisting of alkoxy groups; Wherein m is an integer ranging from 0 to 10; where Y 1a Selected from direct single bond, O, S, NR 5a , O(CO)-* or O(CO)CH 2 The group consisting of O-*, wherein the asterisk indicates a bond to the benzene ring of group (A), (B), (D) or (E); where Y 2a Select from direct single bond, O, S or NR 5a The group composed of; Where R 11a and R 12a Independently of each other, C 1 -C 10 Alkyl, C 2 -C 10 Alkenyl or phenyl, unsubstituted or replaced by C 1 -C 4 Alkyl substituted C 1 -C 4 Alkyl, or R 11a and R 12a Together with the C-atom to which they are attached they form a cyclohexane or cyclopentane ring; Where Z a Is OH or NR 13a R 14a ; Where Z 1a It is C 1 -C 12 Alkoxy or C interrupted by one or more O 2 -C 12 Alkoxy, wherein the C 1 -C 12 Alkoxy or interrupted C 2 -C 12 Alkoxy groups are unsubstituted or substituted with OH; Where R 13a and R 14a Independently of each other, C 1 -C 12 Alkyl, C substituted by one or more OH or halogen 1 -C 12 Alkyl; or Where R 13a and R 14a Together with the N-atom to which they are attached, they form a 5- or 6-membered unsaturated or saturated ring which is uninterrupted or replaced by O or NR 15a interrupt, where R 15a It is C 1 -C 4 alkyl; Where R 16a is hydrogen or C 1 -C 4 Alkyl; provided that (i) If R 1a , R 2a and R 3a As C 1 -C 4 Alkyl is methyl and X is O, then R 4 As C 1 -C 28 Alkyl is not methyl, ethyl, n-propyl, 2-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl; (ii) If R 1a and R 3a As halogen, it is Cl, R 2a is hydrogen and X is O, then R 4a As a replacement of C 3 -C 10 Aryl is not 4-butyl-phenyl; and (iii) If R 1a and R 3a As C 1 -C 4 Alkoxy is methoxy, R 2a is hydrogen, and X is NR 5a , and R 4a With R 5a Together with the N-atom, it forms a 5- or 6-membered saturated ring, then the ring is not a piperidine ring; Among them, Ar 1 and Ar 2 Each independently is or unsubstituted or replaced by R 1c , R 2c , R 3c , R 4c or R 5c one or more substituted naphthyl; Where R 1c and R 5c Each independently selected from C 1 -C 4 Alkyl, C 1 -C 4 a group consisting of alkoxy or halogen; Where R 3c Selected from hydrogen, C 1 -C 4 Alkyl, halogen, C 1 -C 4 Alkoxy or C interrupted by one or more O 2 -C 20 A group consisting of alkoxy groups; Where Q is C 1 -C 4 Alkylene; Where R 2c and R 4c independently of each other are hydrogen or PG c -Y c -Z c -X c -; Among them PG c is a polymerizable group or a methyl group or an ethyl group; where Y c is a direct single bond, O or S; Where X c is a direct single bond, O or S; Where Z c It is a direct single bond, C 1 -C 20 Alkylene or C interrupted by one or more O 2 -C 20 Alkylene; Where R 6c is unsubstituted or is selected from OH and One or more groups substituted with C 3 -C 30 Alkyl; or Where R 6c is one or more O or C 3 -C 8 Cycloalkylene interrupted C 3 -C 28 alkyl, and the interrupted C 3 -C 28 The alkyl group is unsubstituted or is selected from OH and One or more groups are substituted; Where R 1d It is C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy or halogen; Where R 2d It is hydrogen, C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy or halogen; and Where R 3d It is C 1 -C 20 Alkyl, cyclopentyl, cyclohexyl, phenyl-C 1 -C 4 Alkyl, naphthyl, biphenyl or 5- or 6-membered heterocyclic ring containing O, S or N, naphthyl, biphenyl and 5- or 6-membered heterocyclic ring containing O, S or N are unsubstituted or replaced by C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy, halogen, C 1 -C 4 Alkylthio substitution; or Where R 3d yes Where R 4d , R 5d , R 6d , R 7d and R 8d are independently selected from hydrogen, halogen, C 1 -C 20 Alkyl, cyclopentyl, cyclohexyl, C 2 -C 12 Alkenyl, C interrupted by one or more discontinuous O atoms 2 -C 20 Alkyl, phenyl-C 1 -C 4 Alkyl, C 1 -C 20 Alkoxy or unsubstituted or substituted with one or two C 1 -C 4 Alkyl or / and C 1 -C 4 The group consisting of phenyl substituted with alkoxy substituents; and Each A independently represents O, S, NR 3e ; Where G is a multifunctional compound (core) G-(AH) p+q A residue of wherein each AH represents an alcohol group or an amino group or a thiol group; wherein p and q are both integers, p+q is an integer in the range of 3 to 10, and p is an integer in the range of 3 to 8; Where R 1e and R 2e Each independently selected from C 1 -C 18 Alkyl, C 6 -C 12 Aryl and C 5 -C 12 a group consisting of cycloalkyl radicals, each of which is uninterrupted or interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted amino radicals, or R 1e and R 2e is a five- to six-membered heterocyclic group containing oxygen and / or nitrogen and / or sulfur atoms; wherein each of the groups may be substituted by an aryl group, an alkyl group, an aryloxy group, an alkoxy group, a heteroatom and / or a heterocyclic group; R 2e It can also be (CO)R 1e ; Where R3 e is hydrogen or C 1 -C 4 alkyl.

4. The photoinitiator package according to any one of the preceding claims, wherein at least one of the one or more bisacylphosphine oxide photoinitiators has a structure according to formula (XI): Where R 1f Each instance of is independently selected from C 1 -C 4 A group consisting of alkyl groups; Where X f Selected from direct single bond, O, S, NR 4f 、-CH 2 CO 2 -and-CH 2 CH 2 CO 2 - the groups formed; Where R 2f Choose from C 1 -C 40 Alkyl and one or more O or C 3 -C 8 Cycloalkylene interrupted C 2 -C 40 The group consisting of alkyl groups, wherein the C 1 -C 40 Alkyl or interrupted C 2 -C 40 The alkyl group may be unsubstituted or selected from OH and R 3f One or more groups are substituted; Where R 3f yes Where R 4f Selected from hydrogen, (CO)R 5f , phenyl, C 1 -C 12 Alkyl, C interrupted by one or more O 2 -C 12 Alkyl, unsubstituted or substituted with one or more C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy, OH or NCO substituted C 3 -C 12 The group consisting of cycloalkyl groups, wherein the C 1 -C 12 Alkyl or interrupted C 2 -C 12 Alkyl is unsubstituted or substituted with one or more C 3 -C 7 Cycloalkyl, OH substituted or substituted by NCO; and Where R 5f Choose from C 1 -C 12 Alkyl or C interrupted by one or more O 2 -C 12 Alkyl, wherein the C 1 -C 12 Alkyl or interrupted C 2 -C 12 Alkyl is unsubstituted or substituted with one or more C 3 -C 7 Cycloalkyl, OH, NCO substituted or phenyl substituted by NCO; C 3 -C 12 Cycloalkyl; unsubstituted or substituted with one or more C 1 -C 4 Alkyl, OH or C 1 -C 4 Alkoxy substituted C 2 -C 10 Alkenyl; unsubstituted or substituted with C 1 -C 12 Alkyl, C 1 -C 12 Alkoxy, NCO-substituted or NCO-substituted C 1 -C 12 Alkyl substituted C 6 -C 14 A group consisting of aromatic groups.

5. The photoinitiator package according to any one of the preceding claims, wherein at least one of the one or more oxazole-based sensitizers has a structure according to formula (Ia): Where R 1g To R 8g Each independently selected from hydrogen, C 1 -C 10 Alkyl and C 6 -C 14 A group consisting of aromatic groups.

6. A photoinitiator package according to any one of the preceding claims, wherein the one or more oxazole-based sensitizers each having a structure according to formula (II) are selected from the group consisting of 2,5-bis(5-tert-butyl-1,3-benzoxazolyl)thiophene, 2,2'-(vinylenebis-p-phenylene)bisbenzoxazole, 2,2'-(naphthalene-1,4-diyl)bis(benzoxazole), 2-[4-[2-[4-(benzoxazol-2-yl)phenyl]vinyl]phenyl]-5-methylbenzoxazole, 2,2'-(1,4-phenylene)bis[5-phenyl-oxazole].

7. A photoinitiator package according to any one of the preceding claims, wherein the photoinitiator package comprises: a) the one or more monoacyl or bisacylphosphine oxide photoinitiators in an amount ranging from 40 to 98.9 wt.-%, more preferably ranging from 60 to 96.0 wt.-%, most preferably ranging from 65 to 92.0 wt.-% relative to the total weight of the photoinitiator package, b) one or more oxazole-based sensitizers in an amount ranging from 0.1 to 50 wt. %, more preferably ranging from 1.0 to 37 wt. %, most preferably ranging from 3.0 to 30 wt. %, relative to the total weight of the photoinitiator package, each of the one or more oxazole-based sensitizers having a structure according to formula (I), and c) said one or more amines in an amount ranging from 1.0 to 45 wt.-%, more preferably ranging from 3.0 to 35 wt.-%, most preferably ranging from 5.0 to 30 wt.-%, relative to the total weight of said photoinitiator package.

8. A photoinitiator package according to any one of the preceding claims, wherein the only photoinitiator present in the photoinitiator package is a Norrish Type-I photoinitiator or a cationic photoinitiator.

9. A photopolymerizable composition comprising: a) one or more ethylenically unsaturated free-radically polymerizable compounds; b) A photoinitiator package according to any one of claims 1 to 8.

10. The photopolymerizable composition of claim 9, wherein the photopolymerizable composition comprises: a) the one or more ethylenically unsaturated free-radically polymerizable compounds in an amount ranging from 30 to 99.0 wt.-%, more preferably ranging from 50 to 95.0 wt.-%, most preferably ranging from 70 to 90 wt.-%, relative to the total weight of the photopolymerizable composition; b) a photoinitiator package according to any one of claims 1 to 8 in an amount ranging from 0.5 to 50 wt.-%, more preferably ranging from 0.8 to 40 wt.-%, most preferably ranging from 1.0 to 30 wt.-%, relative to the total weight of the photopolymerizable composition.

11. The photopolymerizable composition according to claim 9 or claim 10, wherein the photopolymerizable composition further comprises one or more of the following components: c) one or more additional photoinitiators, one or more photosensitizers and / or one or more co-initiators in an amount in the range of 0.5 to 30 wt.-%, more preferably in the range of 0.8 to 20 wt.-%, most preferably in the range of 1.0 to 15 wt.-%; d) one or more pigments in an amount ranging from 0.1 to 30 wt.-%, more preferably ranging from 1.0 to 25 wt.-%, most preferably ranging from 10 to 20 wt.-% relative to the total weight of the photopolymerizable composition; e) one or more binders in an amount ranging from 5.0 to 60 wt. %, more preferably ranging from 8.0 to 50 wt. %, most preferably ranging from 10 to 40 wt. % relative to the total weight of the photopolymerizable composition; and f) one or more additives in an amount ranging from 0.01 to 10 wt. %, more preferably from 0.01 to 8.0 wt. %, most preferably from 0.01 to 5.0 wt. %, relative to the total weight of the photopolymerizable composition.

12. A method for photocuring a photopolymerizable composition, coating, adhesive and ink, the method comprising: The following steps are involved: a) coating or printing the photopolymerizable composition according to any one of claims 9 to 11 onto a substrate, and b) photopolymerizing the coated or printed composition on the substrate using a light source.

13. Use of a photoinitiator package according to any one of claims 1 to 8 in the production of printing inks, screen printing inks, gravure printing inks, solder masks, etching offset inks, flexographic printing inks, gravure inks, inkjet inks, resist materials, insulators, sealants, image recording materials, solder masks, passivation layers, protective coatings, 3D printed objects and molds, holographic applications, optical fiber coatings, waveguides and lenses, overprint varnishes, wood, vinyl, metal and plastic coatings.

14. Use of a combination of one or more amines and one or more oxazole-based sensitizers for increasing the surface cure rate of a photopolymerizable composition comprising one or more Norrish Type-I photoinitiators.

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