Photoinitiator package comprising dedicated bisacylphosphine oxide photoinitiators and fluorescent whitening agent sensitizers

Abstract

A photoinitiator package comprising one or more bisacylphosphine oxide photoinitiators and one or more fluorescent whitening agent sensitizers, a photopolymerizable composition comprising the photoinitiator package and a suitable polymerizable compound, a process for polymerizing the photopolymerizable composition and the use of the photoinitiator package in photopolymerization applications.

Description

Technical Field

[0001] The present invention relates to a photoinitiator package comprising one or more bisacylphosphine oxide photoinitiators and one or more fluorescent brightener sensitizers, a photopolymerizable composition comprising the photoinitiator package and a suitable polymerizable compound, a method for polymerizing the photopolymerizable composition and the use of the photoinitiator package in photopolymerization applications. 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. In particular, improvements in the surface curing capabilities of phosphine oxide photoinitiators would allow these powerful photoinitiators to be more widely used. Summary of the invention

[0006] The present invention is based on the observation that the combination of a sensitizer and certain bisacylphosphine oxide photoinitiators has unexpectedly excellent photoinitiator properties, including surface curing capabilities.

[0007] Thus, in a first aspect, the present invention relates to a photoinitiator package comprising:

[0008] a) one or more bisacylphosphine oxide photoinitiators, each bisacylphosphine oxide photoinitiator having a structure according to formula (I):

[0009]

[0010] wherein each instance of R is independently selected from the group consisting of C1-C4 alkyl;

[0011] Wherein X is selected from direct single bond, O, S, NR 3 , -CH2CO2- and -CH2CH2CO2-;

[0012] Where R 1 Choose from C1-C 40 Alkyl and interrupted C2-

[0013] C 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 2 One or more groups are substituted;

[0014] Where R 2 yes

[0015] Where R 3 Selected from hydrogen, (CO)R 4 , 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-

[0016] C 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

[0017] Where R 4 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 12The 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;

[0018] b) One or more optical brightener sensitizers (also known as optical brightener sensitizers).

[0019] In a second aspect, the present invention relates to a photopolymerizable composition comprising:

[0020] a) one or more ethylenically unsaturated free-radically polymerizable compounds;

[0021] b) A photoinitiator package according to the first aspect.

[0022] 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:

[0023] a) coating or printing the photopolymerizable composition according to the second aspect onto a substrate, and

[0024] b) photopolymerizing the coated or printed composition on the substrate using a light source.

[0025] In a final aspect, the 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.

[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 "heteroaryl" or "heteroaryl group" includes, for example, substituted or unsubstituted heteroatom-containing aromatic ring systems such as pyridine, pyrrole, furan, triazine, indole, quinolone, thiophene, and the like.

[0030] 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.

[0031] 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.

[0032] The expression "direct bond" means that there is no linking group and a direct bond links the two moieties on either side.

[0033] 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.

[0034] 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.

[0035] The term "photopolymerization package" refers to a combination of one or more photoinitiators and any components that interact with the photoinitiators to affect the photoinitiator properties of the photopolymerization package, such as synergists and / or sensitizers. Not included in the term "photopolymerization package" are photopolymerizable monomers or any other additives that do not affect the photoinitiator properties of the photopolymerization package, such as fillers, pigments, antistatic agents, wetting agents or flow enhancers, adhesion enhancers and / or plasticizers that are present in order to change the properties of the polymerizable composition (such as the flow properties of the polymerizable composition) or the mechanical properties or appearance of the resulting cured composition. Furthermore, in the context of the present invention, the term "photopolymerization package" means that the components of the package are provided together as a blend, preferably in the form of a blend that is liquid at 25°C and standard pressure.

[0036] In the context of the present invention, for a blend to be referred to as a "liquid" it must be a single-phase liquid, i.e. a blend having a suspension of solid and liquid phases would not be classified as a "liquid" in the context of the present invention, nor would a blend having an emulsion having multiple immiscible liquid phases. DETAILED DESCRIPTION

[0037] Bisacylphosphine oxide photoinitiator

[0038] One of the essential features of the photoinitiator package according to the present invention is one or more bisacylphosphine oxide photoinitiators.

[0039] The one or more bisacylphosphine oxide photoinitiators each have a structure according to formula (I)

[0040]

[0041] wherein each instance of R is independently selected from the group consisting of C1-C4 alkyl;

[0042] Wherein X is selected from direct single bond, O, S, NR 3 , -CH2CO2- and -CH2CH2CO2-;

[0043] Where R 1 Choose 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 2 One or more groups are substituted;

[0044] Where R 2 yes

[0045] Where R 3 Selected from hydrogen, (CO)R 4 , 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

[0046] Where R 4 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.

[0047] Each instance of R can be independently selected from C1-C4 alkyl, i.e., selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. It is particularly preferred that each instance of R is selected from methyl and ethyl. Most preferably, each instance of R is methyl.

[0048] X is selected from direct single bond, O, S, NR 3 More preferably, X is selected from the group consisting of a direct single bond, O, -CH2CO2- and -CH2CH2CO2-. Still more preferably, X is selected from the group consisting of a direct single bond, -CH2CO2- and -CH2CH2CO2-. Most preferably, X is a direct single bond.

[0049] When X is selected from the group consisting of a direct single bond, -CH2CO2- and -CH2CH2CO2-, the result is that the phosphorus atom of the bisacylphosphine oxide moiety is bonded to carbon rather than to oxygen, sulfur or nitrogen. Bisacylphosphine oxides having phosphorus bonded to carbon, i.e., X is selected from the group consisting of a direct single bond, -CH2CO2- and -CH2CH2CO2- are particularly preferred due to improved stability and / or improved photoinitiation properties.

[0050] R 1 Choose 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 2 One or more groups are substituted;

[0051] Where R 2 yes

[0052] In some embodiments, there is no R 2 , which means that the structure according to formula (I) has a single bisacylphosphine oxide moiety.

[0053] In such an embodiment, preferably, R 1 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 1 It is C1-C 20 alkyl.

[0054] Particularly preferred are those wherein X is a direct single bond and R 1 It is C1-C 20 Alkyl Embodiments. In such embodiments, it is particularly preferred that every instance of R is methyl.

[0055] Likewise, where X is O and R 1 is -(CH2CH2O-) n CH3 or -(CH2CH2O-) n Also particularly preferred is the embodiment where H. In such an embodiment, it is particularly preferred that every instance of R is methyl.

[0056] In other embodiments, there is R 2In at least one example of this, it is meant that the structure according to formula (I) has more than one bisacylphosphine oxide moiety.

[0057] Such embodiments are preferably described by formula (I), wherein R 1 Having a structure according to formula (II):

[0058]

[0059] wherein each instance of M is independently selected from (CH2CH2O) and (CH2CH(CH3)O);

[0060] wherein each instance of Y is independently selected from hydrogen and C1-C4 alkyl;

[0061] wherein each instance of Z has the structure CH2(M 1 ) c R 2 ;

[0062] Among them, M 1 Each instance of is independently selected from (OCH2CH2) and (OCH(CH3)CH2)

[0063] Wherein a is an integer in the range of 0 to 15;

[0064] Wherein b is an integer in the range of 0 to 6;

[0065] wherein each instance of c is independently an integer in the range of 0 to 15;

[0066] wherein m is an integer in the range of 0 to 2; and

[0067] wherein each instance of X is independently selected from the group consisting of -CH2CO2- and -CH2CH2CO2-.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] When using the glycerol core, R 1 Referred to as "optionally ethoxylated / propoxylated glycerol".

[0073] When using a trimethylolpropane nucleus, R 1 Referred to as "optionally ethoxylated / propoxylated trimethylolpropane".

[0074] When using the pentaerythritol core, R 1 Referred to as "optionally ethoxylated / propoxylated pentaerythritol".

[0075] When using the neopentyl glycol core, R 1 Referred to as "optionally ethoxylated / propoxylated neopentyl glycol".

[0076] When using an ethylene glycol core, R 1 Referred to as "optionally ethoxylated / propoxylated glycol".

[0077] When using the 1,6-hexanediol core, R 1 Referred to as "optionally ethoxylated / propoxylated 1,6-hexanediol".

[0078] 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.

[0079] 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.

[0080] Particularly preferred is R 1 Choose from C1-C 20 Alkyl, -(CH2CH2O-) n CH3 and -(CH2CH2O-) nThe 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.

[0081] When R 1 It is C1-C 20 When alkyl, it is particularly preferred that R 1 It is C1-C 15 Alkyl, more preferably C1-C 12 Examples of particularly preferred bisacylphosphine oxide photoinitiators having a structure according to formula (I) include:

[0082]

[0083]

[0084] wherein each instance of a and each instance of c are independently defined as in formula (II).

[0085] It is particularly preferred that each of the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I) is liquid at 25° C. and standard pressure.

[0086] Fluorescent brightener sensitizer

[0087] Another essential feature of the photoinitiator package according to the present invention is the presence of one or more fluorescent brightener sensitizers.

[0088] 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.

[0089] Furthermore, those skilled in the art will fully appreciate that fluorescent brighteners 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. Fluorescent brighteners have been used in laundry detergents, papermaking, cosmetics and textile whitening, as well as in some photopolymerizable compositions for the purpose of improving the optical properties of the cured composition.

[0090] In the broadest sense, any compound known to act as a fluorescent brightener may be used in the photoinitiator package according to the present invention.

[0091] Examples of such well-known fluorescent whitening agents include compounds having building blocks including stilbene (or stilbene), triazine, thiazole, benzoxazole, coumarin, xanthene, triazole, oxazole, thiophene and pyrazoline.

[0092] Particularly preferred are fluorescent brighteners having a coumarin or (benzo)oxazole core.

[0093] In a first particularly preferred embodiment, at least one of the one or more fluorescent whitening agent sensitizers has a structure according to formula (III):

[0094]

[0095] Where R 3a Selected from hydrogen, C1-C 10 Alkyl, C6-C 14 Aryl and C6-C 14 A group consisting of heteroaryl groups,

[0096] R 4a Selected from hydrogen, C1-C 10 Alkyl and OR 1a The group composed of

[0097] R 5a To R 8a Each is independently selected from hydrogen, halogen, alkyl, OR 1a and NR 2a 2 groups;

[0098] Where R 1a Each instance of is selected from hydrogen, C1-C 10 Alkyl and C6-C 14 Aryl, and R 2a Each instance of is selected from hydrogen, C1-C 10 Alkyl and C6-C 14 Aryl, where R 1a To R 8a Each instance of can optionally be combined with R 1a To R 8a One or more additional instances of are connected to form one or more 5-membered or 6-membered rings.

[0099] In a preferred embodiment, R 3a Selected from hydrogen and C1-C 10 The group consisting of alkyl groups, or R 4a Selected from hydrogen and C1-C 10 Alkyl group.

[0100] In another preferred embodiment, R 3a Selected from hydrogen and C1-C 10 The group is composed of alkyl groups, and R 4a Selected from hydrogen and C1-C 10 Alkyl group.

[0101] In another preferred embodiment, R 7a Choose Free OR 1a and NR 2a 2, most preferably R 7a YesNR 2a 2.

[0102] In a particularly preferred embodiment, R 3a Selected from hydrogen and C1-C 10 The group consisting of alkyl groups, or R 4a Selected from hydrogen and C1-C 10 The group consists of alkyl groups, and R 7a Choose Free OR 1a and NR 2a 2, most preferably R 7a YesNR 2a 2.

[0103] In a particularly preferred embodiment, R 3a Selected from hydrogen and C1-C 10 The group consisting of alkyl groups, R 4a Selected from hydrogen and C1-C 10 The group is composed of alkyl groups, and R 7a Choose Free OR 1a and NR 2a 2, most preferably R 7a YesNR 2a 2.

[0104] At least one of the coumarin-based sensitizers, preferably all selected from coumarin, 7-amino-4-(trifluoromethyl)coumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 7-hydroxy-4-(trifluoromethyl)coumarin, 7-(ethylamino)-4,6-dimethylcoumarin, 7-methoxy-4-(trifluoromethyl)coumarin, 7-ethoxy-4-(trifluoromethyl)coumarin, 7-amino-4-methylcoumarin, 7-(diethylamino)-4-methylcoumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 7-methylcoumarin, 7-methoxycoumarin, 4-hydroxycoumarin, 5,7-dimethoxycoumarin, 3-(3-biphenyl-4-(trifluoromethyl)coumarin, 7-ethoxy-4-(trifluoromethyl)coumarin, 7-amino-4-methylcoumarin, 7-(diethylamino)-4-methylcoumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 7-methylcoumarin, 7-methoxycoumarin, 4-hydroxycoumarin, 5,7-dimethoxycoumarin, 3-(3-biphenyl-4-(trifluoromethyl)coumarin, 7- The group consisting of: -1,2,3,4-tetrahydro-1-naphthyl)-4-hydroxycoumarin, 6-methylcoumarin, 3-chloro-7-hydroxy-4-methylcoumarin, 7-hydroxycoumarin, 7-hydroxy-6-methoxycoumarin, 7-methoxy-6-hydroxycoumarin, 6-hydroxycoumarin, 7,8-dihydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin, 7-(dimethylamino)-4-methylcoumarin, 2,3,6,7-tetrahydro-9-methyl-1H,5H,11H-[1]-benzopyrano[6,7,8-ij]quinolizin-1l-one, 7-(diethylamino)-4-(trifluoromethyl)-coumarin and 7-(ethylamino)-4-(trifluoromethyl)coumarin.

[0105] More preferably, at least one of the coumarin-based sensitizers, preferably all of them, is selected from coumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 7-methoxy-4-(trifluoromethyl)coumarin, 7-ethoxy-4-(trifluoromethyl)coumarin, 7-(diethylamino)-4-methylcoumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 7-methylcoumarin, 7 -methoxycoumarin, 5,7-dimethoxycoumarin, 6-methylcoumarin, 7-(dimethylamino)-4-methylcoumarin, 2,3,6,7-tetrahydro-9-methyl-lH,5H,11H-[1]-benzopyrano[6,7,8-ij]quinolizin-1l-one, 7-(diethylamino)-4-(trifluoromethyl)-coumarin and 7-(ethylamino)-4-(trifluoromethyl)coumarin.

[0106] Most preferably, at least one, preferably all, of the coumarin-based sensitizers are selected from the group consisting of coumarin, 7-(diethylamino)-4-methylcoumarin, 7-methylcoumarin, 7-methoxycoumarin, 5,7-dimethoxycoumarin and 7-(diethylamino)-4-(trifluoromethyl)-coumarin.

[0107] In a second particularly preferred embodiment, at least one of the one or more fluorescent whitening agent sensitizers has a structure according to formula (IV):

[0108]

[0109] Where R 1b To R 4b 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 1b and R 2b To form a 6-membered saturated or unsaturated ring, the 6-membered saturated or unsaturated 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 3b and R 4b To form a 6-membered saturated or unsaturated ring, the 6-membered saturated or unsaturated 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

[0110] wherein A represents a linking group represented by any one of the following formulae (V) to (IX):

[0111]

[0112] Each * represents the bonding position of A in each formula.

[0113] R 1b To R 4b 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 1b and R 2b To form a 6-membered saturated or unsaturated ring, the 6-membered saturated or unsaturated 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 3b and R 4b To form a 6-membered saturated or unsaturated ring, the 6-membered saturated or unsaturated ring can be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 The aryl group is substituted with one or more substituents.

[0114] In one embodiment, R 1b To R 4b Each independently selected from hydrogen, C1-C6 alkyl and C6-C 10 A group consisting of aromatic groups.

[0115] In a particularly preferred embodiment, R 1b and R 3b Both are respectively related to R 2b and R 4b Connected to form a 6-membered saturated or unsaturated ring, the 6-membered saturated or unsaturated ring can be selected from hydrogen, C1-C 10 Alkyl and C6-C 14 The aryl group is substituted with one or more substituents.

[0116] In one embodiment of said particularly preferred embodiment, each 6-membered ring formed is aromatic, meaning that at least one of the one or more oxazole-based sensitizers is a benzoxazole-based sensitizer having a structure according to formula (X):

[0117]

[0118] Where R 1c To R 8c Each independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 A group consisting of aromatic groups.

[0119] Preferably, R 1c To R 8c Each independently selected from hydrogen, C1-C6 alkyl and C6-C 10 A group consisting of aromatic groups.

[0120] In one embodiment, each of the one or more oxazole-based sensitizers has a structure according to Formula (X).

[0121] In other embodiments, at least one of the one or more oxazole-based sensitizers has a structure according to formula (X), while any remaining oxazole-based sensitizers in the photoinitiator package have other structures according to formula (IV).

[0122] Particularly preferred compounds according to formula (IV) 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].

[0123] Photoinitiator Package

[0124] The photoinitiator package according to the present invention comprises one or more bisacylphosphine oxide photoinitiators as described above and one or more fluorescent brightener sensitizers as described above.

[0125] Preferably, the photoinitiator package comprises:

[0126] a) one or more bisacylphosphine oxide photoinitiators in an amount in the range of 15 to 99.9 wt. %, more preferably in the range of 30 to 99.0 wt. %, most preferably in the range of 50 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0127] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt. %, more preferably ranging from 1.0 to 40 wt. %, most preferably ranging from 3.0 to 35 wt. % relative to the total weight of the photoinitiator package.

[0128] In one embodiment, the photoinitiator package comprises:

[0129] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 15 to 99.9 wt % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0130] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt. % relative to the total weight of the photoinitiator package.

[0131] In another embodiment, the photoinitiator package comprises:

[0132] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 30 to 99.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0133] b) one or more fluorescent brightener sensitizers in an amount ranging from 1.0 to 40 wt. % relative to the total weight of the photoinitiator package.

[0134] In yet another embodiment, the photoinitiator package comprises:

[0135] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 50 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0136] b) one or more fluorescent brightener sensitizers in an amount ranging from 3.0 to 35 wt. % relative to the total weight of the photoinitiator package.

[0137] It is further preferred that the photoinitiator package comprises:

[0138] a) one or more bisacylphosphine oxide photoinitiators in an amount in the range of 40 to 99.9 wt. %, more preferably in the range of 60 to 99.0 wt. %, most preferably in the range of 65 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0139] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt. %, more preferably ranging from 1.0 to 40 wt. %, most preferably ranging from 3.0 to 35 wt. % relative to the total weight of the photoinitiator package.

[0140] In one embodiment, the photoinitiator package comprises:

[0141] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 40 to 99.9 wt % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0142] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt. % relative to the total weight of the photoinitiator package.

[0143] In another embodiment, the photoinitiator package comprises:

[0144] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 60 to 99.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0145] b) one or more fluorescent brightener sensitizers in an amount ranging from 1.0 to 40 wt. % relative to the total weight of the photoinitiator package.

[0146] In yet another embodiment, the photoinitiator package comprises:

[0147] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 65 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0148] b) one or more fluorescent brightener sensitizers in an amount ranging from 3.0 to 35 wt. % relative to the total weight of the photoinitiator package.

[0149] In addition to one or more bisacylphosphine oxide photoinitiators and one or more fluorescent brightener sensitizers, the photoinitiator package may also contain one or more amines.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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 effect of the one or more bisacylphosphine oxide photoinitiators and / or one or more optical brightener sensitizers having a structure according to formula (I).

[0154] 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 3Hybridized 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).

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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).

[0159] If present, the one or more amines are preferably present 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.

[0160] Thus, in one embodiment, the photoinitiator package comprises, more preferably consists of:

[0161] a) one or more bisacylphosphine oxide photoinitiators in an amount in the range of 15 to 98.9 wt. %, more preferably in the range of 30 to 96.0 wt. %, most preferably in the range of 50 to 92.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I);

[0162] b) one or more fluorescent brightener 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

[0163] 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.

[0164] In another embodiment, the photoinitiator package comprises, more preferably consists of:

[0165] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 15 to 98.9 wt % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I);

[0166] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt % relative to the total weight of the photoinitiator package; and

[0167] c) one or more amines in an amount ranging from 1.0 to 45 wt. % relative to the total weight of the photoinitiator package.

[0168] In another embodiment, the photoinitiator package comprises, more preferably consists of:

[0169] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 30 to 96.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I);

[0170] b) one or more fluorescent brightener sensitizers in an amount ranging from 1.0 to 37 wt % relative to the total weight of the photoinitiator package; and

[0171] c) one or more amines in an amount ranging from 3.0 to 35 wt. % relative to the total weight of the photoinitiator package.

[0172] In yet another embodiment, the photoinitiator package comprises, more preferably consists of:

[0173] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 50 to 92.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I);

[0174] b) one or more fluorescent brightener sensitizers in an amount ranging from 3.0 to 30 wt. % relative to the total weight of the photoinitiator package; and

[0175] c) one or more amines in an amount ranging from 5.0 to 30 wt. % relative to the total weight of the photoinitiator package.

[0176] When no amine is present, the photoinitiator package preferably comprises, more preferably consists of:

[0177] a) one or more bisacylphosphine oxide photoinitiators in an amount in the range of 50 to 99.9 wt. %, more preferably in the range of 70 to 99.0 wt. %, most preferably in the range of 80 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0178] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt. %, more preferably ranging from 1.0 to 30 wt. %, most preferably ranging from 3.0 to 20 wt. % relative to the total weight of the photoinitiator package.

[0179] In another embodiment, the photoinitiator package comprises, more preferably consists of:

[0180] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 50 to 99.9 wt % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0181] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt. % relative to the total weight of the photoinitiator package.

[0182] In another embodiment, the photoinitiator package comprises, more preferably consists of:

[0183] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 70 to 99.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0184] b) one or more fluorescent brightener sensitizers in an amount ranging from 1.0 to 30 wt. % relative to the total weight of the photoinitiator package.

[0185] In a final embodiment, the photoinitiator package comprises, more preferably consists of:

[0186] a) one or more bisacylphosphine oxide photoinitiators in an amount ranging from 80 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); and

[0187] b) one or more fluorescent brightener sensitizers in an amount ranging from 3.0 to 20 wt. % relative to the total weight of the photoinitiator package.

[0188] If further components are present besides the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I), one or more fluorescent brightener sensitizers and one or more amines, they are preferably further Type-I or Type-II photoinitiators.

[0189] Therefore, preferably, the photoinitiator package comprises one or more bisacylphosphine oxide photoinitiators having a structure of formula (I), one or more fluorescent brightener sensitizers, optionally one or more amines and optionally one or more additional Type-I or Type-II photoinitiators, and more preferably consists of one or more bisacylphosphine oxide photoinitiators having a structure of formula (I), one or more fluorescent brightener sensitizers, optionally one or more amines and optionally one or more additional Type-I or Type-II photoinitiators.

[0190] As understood by those skilled in the art, the term "additional Type-I or Type-II photoinitiators" means that these additional photoinitiators have structures other than the one or more bisacylphosphine oxide photoinitiators having the structure of formula (I).

[0191] Therefore, the photoinitiator package preferably consists of:

[0192] a) one or more bisacylphosphine oxide photoinitiators in an amount in the range of 15 to 98.9 wt. %, more preferably in the range of 30 to 96.0 wt. %, most preferably in the range of 50 to 92.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I);

[0193] b) one or more fluorescent brightener 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;

[0194] c) optionally 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; and

[0195] d) optionally an additional Type-I or Type-II photoinitiator in an amount in the range of 0.0 to 84.9 wt%, more preferably in the range of 0.0 to 69.0 wt%, most preferably in the range of 0.0 to 47.0 wt%.

[0196] If one or more amines are present, the photoinitiator package preferably consists of:

[0197] a) one or more bisacylphosphine oxide photoinitiators in an amount in the range of 15 to 98.9 wt. %, more preferably in the range of 30 to 96.0 wt. %, most preferably in the range of 50 to 92.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I);

[0198] b) one or more fluorescent brightener 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;

[0199] 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; and

[0200] d) optionally an additional Type-I or Type-II photoinitiator in an amount in the range of 0.0 to 83.9 wt%, more preferably in the range of 0.0 to 66.0 wt%, most preferably in the range of 0.0 to 42.0 wt%.

[0201] If no amines are present, the photoinitiator package preferably consists of:

[0202] a) one or more bisacylphosphine oxide photoinitiators in an amount in the range of 15 to 99.9 wt. %, more preferably in the range of 30 to 99.0 wt. %, most preferably in the range of 50 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I);

[0203] b) one or more fluorescent brightener sensitizers in an amount ranging from 0.1 to 50 wt. %, more preferably ranging from 1.0 to 30 wt. %, most preferably ranging from 3.0 to 20 wt. % relative to the total weight of the photoinitiator package; and

[0204] c) optionally an additional Type-I or Type-II photoinitiator in an amount in the range of 0.0 to 84.9 wt%, more preferably in the range of 0.0 to 69.0 wt%, most preferably in the range of 0.0 to 47.0 wt%.

[0205] Furthermore, it is preferred that the photoinitiator package is present in the form of a blend that is liquid at 25°C and standard pressure.

[0206] This means that the one or more bisacylphosphine oxides, one or more fluorescent brightener sensitizers and optionally one or more amines must be miscible and form a stable liquid blend at the indicated temperature and pressure, rather than being present, for example, as a mixture of dry powders or as a suspension or emulsion.

[0207] Photopolymerizable composition

[0208] In a second aspect, the present invention also relates to a photopolymerizable composition.

[0209] In the broadest sense, the photopolymerizable composition comprises or consists of:

[0210] a) one or more ethylenically unsaturated free-radically polymerizable compounds;

[0211] b) A photoinitiator package according to the first aspect.

[0212] Preferably, the photopolymerizable composition comprises or consists of:

[0213] 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;

[0214] 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.

[0215] 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.

[0216] Suitable further components include photosensitizers, further photoinitiators, pigments, binders and customary additives.

[0217] Thus, the photopolymerizable composition comprises, more preferably consists of

[0218] 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;

[0219] 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;

[0220] 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. %;

[0221] 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;

[0222] 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

[0223] 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.

[0224] Additionally, the photopolymerizable composition may be formulated as a composition further comprising water and / or a solvent such as an organic solvent.

[0225] 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.

[0226] The choice of one or more ethylenically unsaturated free radical polymerizable compounds is not particularly limited. The compounds may contain one or more olefinic double bonds. They may be low molecular weight (monomers) or high molecular weight (oligomers) compounds.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] 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.

[0231] 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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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.

[0237] Specific examples of such unsaturated polyamides are methylenebisacrylamide, 1,6-hexamethylene bisacrylamide, diethylenetriaminetrimethylacrylamide, bis(methacrylamidopropoxy)ethane and N-[(β-hydroxyethoxy)ethyl]-acrylamide.

[0238] 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.

[0239] Polybutadiene and polyisoprene and copolymers thereof may also be used.

[0240] 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.

[0241] Examples of photosensitizers are those commonly used in the art, aromatic carbonyl compounds, such as benzophenones, thioxanthones, anthraquinones and 3-acylcoumarin derivatives, terphenyls, styryl ketones and 3-(aroylmethylene)-thiazolines, camphorquinones and also eosin, rhodamine and erythrosine dyes.

[0242] Examples of thioxanthones are thioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-dodecylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 1-methoxycarbonylthioxanthone, 2-ethoxycarbonylthioxanthone, 3-(2-methoxyethoxycarbonyl)thioxanthone, 4-butoxycarbonylthioxanthone, 3-butoxycarbonyl-7-methylthioxanthone, 1-cyano-3-chlorothioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1- Ethoxycarbonyl-3-ethoxythioxanthone, 1-ethoxycarbonyl-3-aminothioxanthone, 1-ethoxycarbonyl-3-phenylsulfonylthioxanthone, 3,4-bis[2-(2-methoxyethoxy)ethoxycarbonyl]thioxanthone, 1-ethoxycarbonyl-3-(1-methyl-1-morpholinoethyl)thioxanthone, 2-methyl-6-dimethoxymethylthioxanthone, 2-methyl-6-(1,1-dimethoxybenzyl)thioxanthone, 2-morpholinomethylthioxanthone, -methyl-6-morpholinylmethylthioxanthone, N-allylthioxanthone-3,4-dicarboximide, N-octylthioxanthone-3,4-dicarboximide, N-(1,1,3,3-tetramethylbutyl)-thioxanthone-3,4-dicarboximide, 1-phenoxythioxanthone, 6-ethoxycarbonyl-1-2-methoxythioxanthone, 6-ethoxycarbonyl-2-methylthioxanthone, thioxanthone-2-polyethylene glycol ester, 2-hydroxy-3-(3,4-dimethyl-9 -oxo-9H-thioxanthone-2-yloxy)-N,N,N-trimethyl-1-propylammonium chloride, or those described in patent application PCT / EP2011 / 069514, such as n-dodecyl-7-methyl-thioxanthone-3-carboxylate and N,N-diisobutyl-7-methyl-thioxanthone-3-urea. Polymeric thioxanthone derivatives (e.g. TX from Rahn AG TX-1 from Lambson Ltd. 7010) is also suitable.

[0243] Examples of benzophenones are benzophenone, 4-phenylbenzophenone, 4-methoxybenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-dimethylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-(4-methylthiophenyl)benzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2-benzoylbenzoic acid methyl ester, 4-(2-hydroxyethylthio)benzophenone , 4-(4-tolylthio)benzophenone, 4-benzoyl-N,N,N-trimethylbenzylamine chloride, 2-hydroxy-3-(4-benzoylphenoxy)-N,N,N-triyl-1-propylamine chloride monohydrate, 4-(13-acryloyl-1,4,7,10,13-pentaoxatridecanyl)benzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyl)oxyethyl]-benzylamine chloride, or those described in US Pat. No. 9,938,231 (e.g. ...-dimethyl-N-[2-(1-oxo-2-propenyl)oxyethyl]-benzylamine chloride 991).

[0244] Polymeric benzophenone derivatives (e.g. all from IGM Resins BV BP, 2702 and 682 from Rahn AG BP-2 and from Lambson Ltd. 7005) is also suitable.

[0245] Examples of 3-acylcoumarin derivatives are 3-benzoylcoumarin, 3-benzoyl-7-methoxycoumarin, 3-benzoyl-5,7-di(propoxy)coumarin, 3-benzoyl-6,8-dichlorocoumarin, 3-benzoyl-6-chlorocoumarin, 3,3'-carbonyl-bis[5,7-di(propoxy)coumarin], 3,3'-carbonyl-bis(7-methoxycoumarin), 3,3'-carbonyl-bis(7-diethylaminocoumarin), 3-isobutyrylcoumarin, 3-benzoyl-5,7-dimethoxycoumarin, 3-benzoyl-5,7-diethoxycoumarin, 3-benzoyl-5,7-dibutoxy ... 7-dimethoxy-5,7-di(methoxyethoxy)coumarin, 3-benzoyl-5,7-di(allyloxy)coumarin, 3-benzoyl-7-dimethylaminocoumarin, 3-benzoyl-7-diethylaminocoumarin, 3-isobutyryl-1,7-dimethylaminocoumarin, 5,7-dimethoxy-3-(1-naphthoyl)coumarin, 5,7-dimethoxy-3(1-naphthoyl)-coumarin, 3-benzoylbenzo[f]coumarin, 7-diethylamino-3-thenoylcoumarin, 3-(4-cyanobenzoyl)-5,7-dimethoxycoumarin, or those described in EP2909243 and WO2017216699.

[0246] Examples of 3-(aroylmethylene)thiazolines are 3-methyl-1,2-benzoylmethylene-β-naphthothiazoline, 3-methyl-2-benzoylmethylene-benzothiazoline, 3-ethyl-2-propionylmethylene-β-naphthothiazoline.

[0247] Examples of other aromatic carbonyl compounds are acetophenone, 3-methoxyacetophenone, 4-phenylacetophenone, benzil such as described in WO2013 / 164394, 2-acetylnaphthalene, 2-naphthaldehyde, 9,10-anthraquinone, 9-fluorenone, dibenzosuberone, xanthone, 2,5-bis(4-diethylaminobenzylidene)cyclopentanone, α-(p-dimethylaminobenzylidene), ketones (such as 2-(4-dimethylamino-benzylidene)-indan-1-one or 3-(4-dimethylaminophenyl)-1-indan-5-yl-propenone), 3-phenylthiophthalimide, N-methyl-3,5-bis(ethylthio)phthalimide.

[0248] Particularly preferred are thioxanthones and 3-acylcoumarins.

[0249] 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.

[0250] Examples of other suitable photoinitiators are camphorquinone, benzophenone, benzophenone derivatives, acetophenone, acetophenone derivatives, dialkoxyacetophenones, α-hydroxyketones, α-aminoketones, 4-aroyl-1,3-dioxolanes, benzoin alkyl ethers and benzil ketals (e.g. benzil dimethyl ketal), ketosulfones (e.g. 1-[4-[(4-benzoyl-phenyl)-thio]-phenyl]-2-methyl-2-[(4-methyl-phenyl)-sulfonyl]-propan-1-one (Teflon® from IGM Resins BV), 1001), 3-ketocoumarins, for example as described in EP2909243 and WO2017216699), phenylglyoxylic esters and their derivatives, diphenylglyoxylic esters, peresters (for example, benzophenonetetracarboxylic acid peresters as described in EP 126 541), acylphosphine photoinitiators (which can be selected from monoacylphosphine oxides, bisacylphosphine oxides, triacylphosphine oxides and multifunctional monoacylphosphine oxides or bisacylphosphine oxides), halomethyltriazines, hexaarylbisimidazole / coinitiator systems (for example a combination of o-chlorohexaphenylbisimidazole and 2-mercaptobenzothiazole), ferrocenium compounds or titanocenes (for example dicyclopentadienyl-bis(2,6-difluoro-3-pyrrolophenyl)titanium), o-acyloxime ester photoinitiators.

[0251] 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-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-ethyl-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).

[0252] Examples of o-acyl oxime ester photoinitiators are 1,2-octanedione, 1-[4-(phenylthio)phenyl]-2-(o-benzoyl oxime), ethyl ketone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]1-(o-acetyl oxime) or those described in GB2339571.

[0253] 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).

[0254] 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.

[0255] 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.

[0256] Any pigment known to those skilled in the art may be used in the photopolymerizable composition.

[0257] 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.

[0258] 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)).

[0259] Suitable examples of coinitiators (also referred to as accelerators) are alcohols, thiols, thioethers, amines or ethers having an available hydrogen bonded to a carbon adjacent to a heteroatom, disulfides and phosphines, for example as described in EP 438 123 and GB 2180358. Suitable examples of amine accelerators / coinitiators include, but are not limited to, aliphatic amines, alicyclic amines, aromatic amines, aryl-aliphatic amines, heterocyclic amines, oligomeric amines or polymeric amines. They may be primary, secondary or tertiary amines, for example butylamine, dibutylamine, tributylamine, cyclohexylamine, benzyldimethylamine, dicyclohexylamine, N-phenylglycine, triethylamine, phenyl-diethanolamine, triethanolamine, piperidine, piperazine, morpholine, pyridine, quinoline, esters of dimethylaminobenzoic acid, Michler's ketone (4,4'-bisdimethylaminobenzophenone) and its derivatives. As amine accelerators / coinitiators, amine-modified acrylate compounds may be used; examples of such amine-modified acrylates include acrylates modified by reaction with primary or secondary amines as described in US 3,844,916, EP 280222, US 5,482,649 or US 5,734,002. Polyfunctional amines and polymeric amine derivatives are also suitable as coinitiators, some examples being acrylates from IGM Resins BV. ASA, from Rahn AG AB-2, from Lambson Ltd. 7040 or those described in US2013 / 0012611.

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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).

[0264] 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.

[0265] method

[0266] 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:

[0267] a) coating or printing the photopolymerizable composition according to the second aspect onto a substrate, and

[0268] b) photopolymerizing the coated or printed composition on the substrate using a light source.

[0269] Preferably, the light source operates in the near-UV or visible range of the EM spectrum.

[0270] 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.

[0271] use

[0272] In a final aspect, the 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.

[0273] 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.

[0274] Example

[0275] A. Determination Method

[0276] 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.

[0277] B. Experiment

[0278] 1. Materials used

[0279] The following commercially available compounds were used in the preparation of the reference preparation, the preparation of the present invention and the comparative preparation:

[0280] PI-I: Bis(2,4,6-trimethylbenzoyl)octylphosphine oxide prepared as in US Pat. No. 5,534,559 A.

[0281] PI-C1: Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, CAS#: 75980-60-8, available as Omnirad TPO

[0282] Commercially available from IGM Group BV (The Netherlands).

[0283] PI-C2: Bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, CAS#: 145052-34-2, commercially available as Omnirad 403 from IGM Group BV (The Netherlands).

[0284] PI-C3: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, CAS#: 162881-26-7, commercially available as Omnirad 819 from IGM Group BV (The Netherlands).

[0285] S1: 7-Diethylamino-4-methylcoumarin, CAS#: 91-44-1, commercially available as Coumarin 1 from Merck KGaA (Germany).

[0286] S2: 2,5-Bis(5-tert-butyl-1,3-benzoxazolyl)thiophene, CAS#: 7128-64-5, available as OmnistabOB

[0287] Commercially available from IGM Group BV (The Netherlands).

[0288] S3: 2,3,6,7-Tetrahydro-9-methyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one, CAS#: 41267-76-9, commercially available as Coumarin 102 from abcr GmbH (Germany).

[0289] A1: 1H-Aza-1-propionic acid, hexahydro-2,2-bis[[(1-oxo-2-propen-1-yl)oxy]methyl]butyl ester, can be used as

[0290] Photomer 4250 was commercially available from IGM Group BV (The Netherlands).

[0291] A2: Poly(ethylene glycol) bis(p-dimethylaminobenzoate), CAS#: 71512-90-8, available as Omnipol ASA

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

[0293] Mi: 40:30:30 photopolymerizable monomer blend of M1, M2 and M3.

[0294] M-ii: 50:15:15:20 photopolymerizable monomer blend of M1, M4, M5 and M6.

[0295] M-iii: 50:25:25 photopolymerizable monomer blend of M1, M4 and M6.

[0296] M1: Bisphenol Y epoxy diacrylate, CAS#: 55818-57-0, commercially available as Photomer 3016 from IGM Group B.V. (The Netherlands).

[0297] M2 glyceryl [4PO] triacrylate, CAS#: 52408-84-1, is commercially available as Photomer 4094 from IGM Group B.V. (The Netherlands).

[0298] M3 trimethylolpropane triacrylate, CAS#: 15625-89-5, is commercially available as Photomer 4006 from IGM Group BV (The Netherlands).

[0299] 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).

[0300] M5 dipentaerythritol penta / hexaacrylate, CAS#: 1384855-91-7, commercially available as Photomer 4600 from IGM Group BV (The Netherlands).

[0301] M6 pentaerythritol [5EO] tetraacrylate, CAS#: 51728-26-8, is commercially available as Photomer 4172 from IGM Group BV (The Netherlands).

[0302] 2. Preparation (Photopolymerizable Composition)

[0303] The following reference, 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 (if present) at the concentrations shown in Table 1 to the photopolymerizable monomer blend M (i.e., Mi, M-ii or M-iii) 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):

[0304] Table 1a: Formulations of reference preparations, preparations according to the invention and comparative preparations using monomer blend Mi

[0305]

[0306] Table 1b: Formulations of additional reference preparations, preparations according to the invention and comparative preparations using monomer blends M-ii or M-iii

[0307]

[0308] 3. Surface photocuring evaluation

[0309] 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 photocuring ability of the reference formulation, the formulation of the present invention and the comparative formulation:

[0310] Table 2a: Performance of Mi formulations in surface photocuring

[0311]

[0312] *n / m = not measured

[0313] Lamp 1: UV Hg lamp with an intensity of 120 W / cm2 at a distance of 8 cm.

[0314] Lamp 2: UV Hg lamp with an intensity of 85 W / cm2 and a distance of 8 cm.

[0315] Lamp 3: wavelength 395nm and intensity 4W / cm 2 The UV LED light is at a distance of 0.5cm.

[0316] Light 4: wavelength 365nm and intensity 4W / cm 2 The UV LED light is at a distance of 0.5cm.

[0317] Lamp 5: wavelength 278nm and intensity 4W / cm 2 The UV LED light is at a distance of 0.5cm.

[0318] Table 2b: Performance of M-ii and M-iii formulations in surface photocuring

[0319]

[0320] Lamp 1: UV Hg lamp with an intensity of 120 W / cm2 at a distance of 8 cm.

[0321] Lamp 6: wavelength 395nm and intensity 16W / cm 2 The UV LED light is at a distance of 0.5cm.

[0322] Lamp 7: wavelength 365nm and intensity 16W / cm 2 The UV LED light is at a distance of 0.5cm.

[0323] As can be seen from the data in Table 2a, sensitizers S1 and S2 increased the surface cure rate for almost all combinations; however, in the absence of sensitizers, while the inventive photoinitiator (PI-I) was generally similar to or inferior to the comparative photoinitiators (i.e., RE4 vs. RE1 to RE3), the combination of the inventive photoinitiator with sensitizers S1 and S2 provided inventive formulations (IE1 and IE2) that were much more active (as seen by increased cure rate) than the same formulations with the comparative photoinitiators.

[0324] When using Lamp 1, the cure rates of the inventive compositions (IE1 and IE2) were more than twice that of the reference example (RE4), while the comparative compositions generally had more modest improvements, generally ranging from 10 to 44% (CE1 to CE5) over the original cure rates (RE1 to RE3). In general, the activity of the inventive compositions exceeded the limits of the test, so the improvements are likely to be even higher.

[0325] In fact, for Lamps 2 to 5, where the initial activities of RE1 to RE4 were generally much lower, the effect of the inventive combination was even more pronounced, with dramatic improvements in reactivity ranging from 5 to 8 fold improvements. In contrast, the magnitude of improvement for the comparative combinations was much smaller, e.g. <10 vs. 71 for RE4 vs. IE2 (Lamp 3), compared to <10 vs. 31 for RE1 vs. CE2, <10 vs. 35 for RE2 vs. CE4, and 12 vs. 56 for RE3 vs. CE6.

[0326] It must be noted that the benzoxazole sensitizer S2 was particularly effective with Lamp 5, while Lamp 5 showed poor reactivity with all other combinations.

[0327] IE3 and IE4 demonstrate that the inventive combination of PI-1 with S1 or S2 can be further improved by adding amine additives, with even better surface cure being observed in all cases (IE3 / IE4 vs. IE1 / IE2, respectively).

[0328] The data in Table 2b further reinforce the conclusions drawn from Table 2a, where despite the lower amount of photoinitiator, it is observed that IE5 to IE9 all exhibit improved surface cure (relative to RE5), with a 4:1 blend ratio (IE6) being particularly effective, as is the use of the benzoxazole-based sensitizer S2 (IE9). Similar effects can be seen by comparing IE10 to IE14 to RE6 and RE7. Again, the use of amines is shown to be particularly beneficial (IE8 vs. IE7, IE14 vs. IE10, IE15 vs. IE10, IE16 vs. IE11, IE17 vs. IE13).

[0329] 4. Photoinitiator package in the form of a liquid blend

[0330] The photopolymerizable package of the present invention can also be prepared in the form of a liquid blend. The photoinitiator is added to a three-necked round-bottom flask under stirring, and the temperature is slowly raised to 60°C. Then, the sensitizer and amine (if present - see Table 3) are added, and the solution is stirred for another hour at 80°C. The clear solution is then slowly cooled at room temperature to obtain a liquid blend, which can be directly used to prepare a polymerizable composition.

[0331] Table 3: Formulations for photoinitiator packages

[0332]

[0333] *-No reprecipitation

[0334] As can be seen from Table 3, the photoinitiator packages of the present invention are in liquid form, whereas those using comparative photoinitiators cannot be so prepared. Liquid blends are preferred because this avoids any problems associated with dissolving the package during preparation of the photopolymerizable composition and shortens the time required to prepare the composition.

[0335] In addition, samples of IE21 were stored at 4°C, 20°C, 40°C and 60°C for 3 months. No decrease in reactivity was observed for samples stored at 4°C, 20°C or 40°C, with the 60°C sample experiencing a slight decrease in reactivity over 3 months (the maximum tack-free speed dropped from 49 m / min to 42 m / min. All samples maintained a constant viscosity over the test period (i.e., 3 months).

[0336] Photopolymerizable compositions (i.e., formulations comparable to those in Table 2) were prepared by adding photopolymerizable monomer blend M, a photoinitiator package in the form of a liquid blend at room temperature. The formulation was stirred at 40°C for 1 hour, and after cooling at room temperature, the formulation was applied to a varnished paperboard at a thickness of 12 microns using a bar coater, and then photopolymerized using a light source in the same manner as in Table 3 above.

[0337] Formulations equivalent to IE1, IE3, IE5 and IE6 were prepared in this manner (i.e. by mixing IE18, IE19, IE20 or IE21 with Mi or M-ii in appropriate ratios) and the results of the surface cure evaluation were identical to those reported in Table 3, demonstrating that the method of preparing the photopolymerizable composition is not critical in this case, only that liquid blends are preferred for procedural economy.

Claims

1. A photoinitiator package comprising: a) one or more bisacylphosphine oxide photoinitiators, each bisacylphosphine oxide photoinitiator having a structure according to formula (I): wherein each instance of R is independently selected from the group consisting of C1-C4 alkyl; Wherein X is selected from direct single bond, O, S, NR 3 , -CH2CO2- and -CH2CH2CO2-; Where R 1 Choose 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 2 One or more groups are substituted; Where R 2 yes Where R 3 Selected from hydrogen, (CO)R 4 , 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 Where R 4 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; b) One or more fluorescent brightener sensitizers.

2. The photoinitiator package of claim 1, wherein each instance of R is Me.

3. A photoinitiator package according to claim 1 or claim 2, wherein X is selected from the group consisting of a direct single bond, O, -CH2CO2- and -CH2CH2CO2-, more preferably selected from the group consisting of a direct single bond, -CH2CO2- and -CH2CH2CO2-, most preferably a direct single bond.

4. A photoinitiator package according to any one of the preceding claims, wherein R 1 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, more preferably R 1 It is C1-C 20 alkyl.

5. The photoinitiator package according to any one of claims 1 to 4, wherein R 1 Having a structure according to formula (II): wherein each instance of M is independently selected from (CH2CH2O) and (CH2CH(CH3)O); wherein each instance of Y is independently selected from hydrogen and C1-C4 alkyl; wherein each instance of Z has the structure CH2(M 1 ) c R 2 ; Among them, M 1 Each instance of is independently selected from (OCH2CH2) and (OCH(CH3)CH2) Wherein a is an integer in the range of 0 to 15; Wherein b is an integer in the range of 0 to 6; wherein each instance of c is independently an integer in the range of 0 to 15; wherein m is an integer in the range of 0 to 2; and wherein each instance of X is independently selected from the group consisting of -CH2CO2- and -CH2CH2CO2-.

6. The photoinitiator package according to any one of the preceding claims, wherein at least one of the one or more fluorescent brightener sensitizers has a structure according to formula (III): Where R 3a Selected from hydrogen, C1-C 10 Alkyl, C6-C 14 Aryl and C6-C 14 A group consisting of heteroaryl groups, R 4a Selected from hydrogen, C1-C 10 Alkyl and OR 1a The group consisting of C1-C 10 The alkyl group may be substituted with one or more fluorine atoms, and R 5a To R 8a Each independently selected from hydrogen, halogen, C1-C 10 Alkyl, OR 1a and NR 2a 2 groups; Where R 1a Each instance of is independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 Aryl, R 2a Each instance of is independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 Aryl, where R 1a To R 8a Each instance of can optionally be combined with R 1a To R 8a One or more additional instances of are connected to form one or more 5-membered or 6-membered rings.

7. The photoinitiator package according to any one of the preceding claims, wherein at least one of the one or more fluorescent brightener sensitizers has a structure according to formula (IV): Where R 1b To R 4b 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 1b and R 2b To form a 6-membered saturated or unsaturated ring, the 6-membered saturated or unsaturated 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 3b and R 4b To form a 6-membered ring, the 6-membered 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 wherein A represents a linking group represented by any one of the following formulae (V) to (IX): Each * represents the bonding position of A in each formula.

8. The photoinitiator package of claim 7, wherein at least one of the one or more fluorescent whitening agent sensitizers has a structure according to formula (X): Where R 1c To R 8c Each independently selected from hydrogen, C1-C 10 Alkyl and C6-C 14 A group consisting of aromatic groups.

9. A photoinitiator package according to any one of the preceding claims, wherein the photoinitiator package comprises: a) the one or more bisacylphosphine oxide photoinitiators in an amount in the range of 40 to 99.9 wt. %, more preferably in the range of 60 to 99.0 wt. %, most preferably in the range of 65 to 97.0 wt. % relative to the total weight of the photoinitiator package, the one or more bisacylphosphine oxide photoinitiators having a structure according to formula (I); b) the one or more fluorescent whitening agent sensitizers in an amount ranging from 0.1 to 50 wt.-%, more preferably ranging from 1.0 to 40 wt.-%, most preferably ranging from 3.0 to 35 wt.-% relative to the total weight of the photoinitiator package; and c) optionally 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.

10. A photoinitiator package according to any one of the preceding claims, in the form of a blend which is liquid at 25°C and standard pressure.

11. 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 10.

12. The photopolymerizable composition of claim 11, 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 10 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.

13. The photopolymerizable composition of claim 11 or claim 12, 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.

14. A method for photocuring a photopolymerizable composition, coating, adhesive and ink, said method comprising the following steps in the given order: a) coating or printing the photopolymerizable composition according to any one of claims 11 to 13 onto a substrate, and b) photopolymerizing the coated or printed composition on the substrate using a light source.

15. Use of a photoinitiator package according to any one of claims 1 to 10 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.

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