Certain benzopyrylium salts as dyes for photopolymer compositions

Abstract

The present invention relates to benzopyrylium dyes of formula (I), wherein R 200 , R 201 , R 202 , R 203 , R 204 , R 205 , R 206 , R 207 and R 208 are each independently hydrogen, C1- to C 16 -Alkyl, C4- to C7-cycloalkyl, C7- to C 16 -Aralkyl, C6-~C 10 -(het) aryl, hydroxy, C1- to C6-alkoxy or dialkylamino, where dialkylamino is selected from the group consisting of diethylamino, dimethylamino, diisopropylamino, a 6-membered saturated ring (which may contain N or O and may be substituted by any non-ionic group) linked via the N of the amino group, or a combination of at least two thereof, and / or R 200 and R 201 Or R 201 and R 202 Or R 202 and R 203 and / or R 205 and R 206 and / or R 206 and R 207 each independently form a -CH=CH-CH=CH- bridge, A represents a -CH2 or -CH2-CH2- bridge, and an anion An n- has a molecular weight of 200 g / mol or more and does not contain halogen atoms. [Formula 1] TIFF2025532501000025.tif56168

Description

[Technical Field]

[0001] The present invention relates to benzopyrylium dyes, in particular in the form of benzopyrylium salts, which can be used as dyes in photopolymer compositions for holographic media. Furthermore, the synthesis of certain benzopyrylium salts is disclosed, along with photopolymer compositions comprising at least a matrix polymer, a write monomer, and a photoinitiating system (PIS), the PIS comprising at least one benzopyrylium salt according to the invention as a dye; holographic media comprising a matrix polymer, a write monomer, and a PIS, the PIS comprising at least one benzopyrylium salt according to the invention as a dye; and layer structures and displays comprising holographic media according to the invention, each of which is the subject of the present invention. [Background technology]

[0002] A wide variety of different photopolymer compositions are known in the prior art. For example, International Publication No. 2008 / 125229 describes a photopolymer composition and photopolymers obtained therefrom, comprising a polyurethane matrix polymer, one or more acrylate-based writing monomers, and a PIS containing a coinitiator and at least one dye. In the context of photopolymer use, the refractive index modulation Δn produced by holographic exposure plays a crucial role. In holographic exposure, the interference field created by a signal beam and a reference beam (in the simplest case, the interference field of two plane waves) is mapped onto a refractive index grating by local photopolymerization of a writing monomer, such as a high-refractive-index acrylate, at locations of high intensity in the interference field. The refractive index grating (hologram) in the photopolymer contains all the information from the signal beam. The signal can be reconstructed by illuminating the hologram with only the reference beam. The intensity of the reconstructed signal relative to the intensity of the irradiated reference beam is called the diffraction efficiency, hereinafter sometimes simply referred to as DE.

[0003] For the simplest hologram, obtained from the superposition of two plane waves, DE is the ratio of the intensity of the diffracted light during reconstruction to the sum of the intensities of the diffracted and undiffracted light. The higher the DE, the more efficient the hologram is with respect to the amount of reference light required to visualize the signal at a given brightness. However, in many holographic applications of photopolymer compositions and the resulting holographic media, it is not just holographic performance that plays an important role. It is also important that the media have good bleachability, i.e., high transmittance across the entire visible spectral range from 400 nm to 800 nm. This depends largely on the dye used in the photopolymer composition's photoinitiator system.

[0004] Many authors have already mentioned suitable dyes for photopolymers. For example, EP 2638544 describes a wide variety of different cationic dyes that can be used as sensitizers to interact with coinitiators such as triarylalkylborate salts in photopolymer compositions. In addition to the aforementioned good bleachability, the main requirements for such dyes are rapid initiation of radical polymerization via electron or energy transfer with the appropriate coinitiator to avoid the formation of inhomogeneities or turbidity in the photopolymer, as well as good compatibility with the other components of the photopolymer composition. According to EP 2638544, the following dye types are highly suitable for photopolymers: Acridine dyes, xanthene dyes, thioxanthene dyes, phenazine dyes, phenoxazine dyes, phenothiazine dyes, tri(het)arylmethane dyes, in particular diamino- and triamino(het)arylmethane dyes, mono-, di- and trimethine cyanine dyes, hemicyanine dyes, external cationic merocyanine dyes, external cationic neutrocyanine dyes, zeromethine dyes, in particular naphtholactam dyes, streptocyanine dyes. Dyes of this type are also described, for example, in H. Berneth in Ullmann's Encyclopedia of Industrial Chemistry, Azine Dyes, Wiley-VCH Verlag, 2008, H. Berneth in Ullmann's Encyclopedia of Industrial Chemistry, Methine Dyes and Pigments, Wiley-VCH Verlag, 2008, and T. Gessner and U. Mayer in Ullmann's Encyclopedia of Industrial Chemistry, Triarylmethane and Diarylmethane Dyes, Wiley-VCH Verlag, 2000. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2008 / 125229 [Patent Document 2] European Patent No. 2638544 [Non-patent literature]

[0006] [Non-Patent Document 1] H. Berneth in Ullmann's Encyclopedia of Industrial Chemistry, Azine Dyes, Wiley-VCH Verlag, 2008 [Non-patent document 2] H. Berneth in Ullmann's Encyclopedia of Industrial Chemistry, Methine Dyes and Pigments, Wiley-VCH Verlag, 2008 [Non-patent document 3] T. Gessner, U. Mayer in Ullmann's Encyclopedia of Industrial Chemistry, Triarylmethane and Diarylmethane Dyes, Wiley-VCH Verlag, 2000 Summary of the Invention [Problem to be solved by the invention]

[0007] However, it has been found that although these known dyes can achieve very good holographic performance, the bleachability criteria are still not satisfactorily met.

[0008] It was therefore an object of the present invention to provide a dye which at least partially overcomes one of the aforementioned drawbacks.It was also an object of the present invention to provide a photopolymer composition of the above type which, after bleaching with the aid of a suitable radiation source, results in a particularly high transmittance across the entire visible spectral range. [Means for solving the problem]

[0009] Surprisingly, it has been found that the use of certain benzopyrylium salts as dyes in photopolymer compositions of the type described above provides higher transmittance across the visible spectral range from 400 nm to 800 nm than currently known dyes, such as the dyes from EP 2 638 544.

[0010] A first subject of the present invention is a benzopyrylium dye of formula (I) [ka] During the ceremony, R 200 , R 201 , R 202 , R 203 , R 204 , R 205 , R 206 , R 207 and R 208 are each independently hydrogen, alkyl, preferably C1 to C 16 Alkyl, particularly preferably C1-C 10 Alkyl, more preferably C1-C6 alkyl, particularly preferably C1-C4 alkyl, most preferably methyl; cycloalkyl, preferably C4-C7 cycloalkyl, particularly preferably C5-C6 cycloalkyl; aralkyl, preferably C7-C 16 Aralkyl, particularly preferably C8-C 12 Aralkyl, aryl, preferably phenyl, (het)aryl, preferably C-C 10 (het) aryl, hydroxyl, alkoxy, preferably C1-C6 alkoxy, particularly preferably methoxy or dialkylamino; A is a -CH2- or a -CH2-CH2- bridge, Anion An n- has a molecular weight of 200 g / mol or more, does not contain halogen atoms, and n is 1 to 3. More preferably, the anion An n-has a molecular weight of 250 g / mol or more, more preferably 300 g / mol or more, particularly preferably 350 g / mol or more. The anion An- preferably has a molecular weight in the range of 200 g / mol to 1000 g / mol, more preferably 250 g / mol to 900 g / mol, particularly preferably 300 g / mol to 800 g / mol, and particularly preferably 350 g / mol to 700 g / mol. Related to benzopyrylium dyes.

[0011] Preferably, R 200 and R 201 , or R 201 and R 202 , or R 202 and R 203 , or R 205 and R 206 , or R 206 and R 207 together, each independently of the other, form a -CH=CH-CH=CH bridge.

[0012] Preferably, (het)aryl is an aryl radical substituted at at least one position with a heteroatom such as O, N, P, S, or a combination thereof.

[0013] Dialkylamino is preferably a 5- or 6-membered saturated ring, bonded via the N of the amino group, and may further contain N or O and / or be substituted with a non-ionic radical, preferably selected from the group consisting of alkyl, alkoxy, hydroxyl, thiol, aryl, (het)aryl, amine, amide or a combination of at least two thereof.

[0014] It has been found that when at least one dye of formula (I) is included in a photopolymer composition, the photopolymer enjoys particularly good bleachability, in addition to high DE and Δn values, rapid initiation of radical polymerization, and high compatibility with the other components of the photopolymer composition. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows the holographic test setup in which the diffraction efficiency (DE) of the holographic media was measured. [Figure 2] Plots of the coupled-wave theory Bragg curve η (dashed line), the measured diffraction efficiency (black circles), and the transmitted power (black solid line) versus the angular detuning ΔΩ are shown. DETAILED DESCRIPTION OF THE INVENTION

[0016] In one preferred embodiment of the benzopyrylium dye of formula (I), R 200 , R 205 , R 207 and R 208 are each hydrogen and A is a -CH-CH- bridge. Preferably, R 201 , R 202 , R 203 and R 206 are each independently hydrogen, C1 to C 16 Alkyl, C4-C7 cycloalkyl, C7-C 16 Aralkyl, C6-C 10 (het) a radical selected from the group consisting of aryl, hydroxyl, C1-C6 alkoxy, or dialkylamino; R 204 is a radical selected from the group consisting of hydrogen, C1-C4 alkyl or optionally substituted (het)aryl radicals, or R 201 and R 202 , or R 202 and R 203 together form a -CH=CH-CH=CH- bridge. Dialkylamino is preferably selected from the group consisting of diethylamino, dimethylamino, diisopropylamino, a 6-membered saturated ring bonded via the N of the amino group, which may further contain N or O and may be substituted by any non-ionic radical, or a combination of at least two thereof.

[0017] In one particularly preferred embodiment of the benzopyrylium dye of formula (I), R200 , R 205 , R 207 and R 208 is hydrogen, A is a -CH2-CH2- bridge, and R 201 is selected from the group consisting of hydrogen, C1-C4 alkyl, hydroxyl, C1-C4 alkoxy, and dialkylamino, wherein dialkylamino is selected from the group consisting of diethylamino, dimethylamino, diisopropylamino, a 6-membered saturated ring bonded through the N of the amino group (which may further contain N or O and may be substituted with any non-ionic group), or a combination of at least two thereof; R 202 is hydrogen, C1-C4 alkyl, hydroxyl or C1-C4 alkoxy, and R 203 is hydrogen or R 202 together with R to form a -CH=CH-CH=CH- bridge. 204 is hydrogen, C1-C4 alkyl or optionally substituted (het) aryl radical, and R 206 is hydrogen, hydroxyl or C1-C4 alkoxy.

[0018] More preferably, in one preferred embodiment of the benzopyrylium dye of formula (I), R 201 is a radical selected from the group consisting of hydrogen, methyl, ethyl, methoxy, ethoxy, dimethylamino and diethylamino.

[0019] The following benzopyrylium dyes (III) to (VIII) are particularly preferred. [ka]

[0020] Preferably, the anion An of the above benzopyrylium cation n-(where n=1) is an anion having a molecular weight of 200 g / mol or more selected from the group of optionally substituted phosphates, optionally substituted phosphonates, optionally substituted sulfonimides, optionally substituted organic borates such as tetraarylborates, triarylalkylborates or cyanotriarylborates, optionally substituted alkyl or alkenyl sulfates, optionally substituted mono- or di-sulfonates such as sulfosuccinates, or optionally substituted organic mono- or di-carboxylates.

[0021] In a preferred embodiment of the benzopyrylium dye, the anion An n- is C8~C 25 Alkanesulfonates, preferably C 13 ~C 25 Alkanesulfonates, C9-C 25 Alkanoates, C9-C 25 Alkenoates, C8-C 25 Alkyl sulfates, preferably C 13 ~C 25 Alkyl sulfates, C8-C 25 Alkenyl sulfates, preferably C 13 ~C 25 Alkenyl sulfates, polyether sulfates based on at least 5 equivalents of ethylene oxide or 5 equivalents of propylene oxide, bis-(C4-C 25 Alkyl-, C5-C7 cycloalkyl-, C3-C8 alkenyl- or C7-C 11 Aralkyl-)sulfosuccinates, C8-C 25 Alkyl sulfoacetates, C4-C 25 Alkyl and / or C1-C 12 Benzenesulfonate substituted with at least one radical of alkoxycarbonyl group, nitro, cyano, hydroxyl, C1-C 25 Alkyl, C1-C 12 Alkoxy, amino or C1-C 12Naphthalene or biphenyl sulfonate optionally substituted with alkoxycarbonyl, nitro, cyano, hydroxyl, C1-C 25 Alkyl, C1-C 12 Alkoxy or C1-C 12 Benzene-, naphthalene- or biphenyl disulfonate optionally substituted with alkoxycarbonyl, dinitro, C6-C 25 Alkyl, C4-C 12 alkoxycarbonyl, benzoyl or toluoyl substituted benzoates.

[0022] Furthermore, the anion is preferably a sulfonated or sulfated, at least monounsaturated, C8-C, anion of naphthalenedicarboxylic acid, diphenyl ether disulfonate, aliphatic C1-C8 alcohol or glycerol. 25 Fatty acid ester, bis(sulfo-C2-C6 alkyl)-C3-C 12 Alkanedicarboxylic acid esters, bis(sulfo-C2-C6 alkyl) itaconates, (sulfo-C2-C6 alkyl)-C6-C 18 Alkane carboxylic acid esters, (sulfo-C2-C6 alkyl) acrylic or methacrylic acid esters, triscatechol phosphate, tetraphenylborate, cyanotriphenylborate, tetraphenoxyborate, C4-C 12 Alkyl-triphenylborates (wherein the phenyl or phenoxy radicals may be substituted by C1-C4 alkyl and / or C1-C4 alkoxy), C4-C 12 Alkyl-trinaphthyl borate, tetra-C1-C 20 Alkoxyborates, mono- or di-negatively charged 7,8- or 7,9-dicarbanidoundecaborates (which contain one or two C1-C 12 optionally substituted on the B and / or C atoms by alkyl or phenyl groups), divalently negatively charged dodecahydrodicarbadodecaborate or B-C1 to C 12alkyl-C-phenyldodecahydrodicarbadodecaborate, or a mixture of at least two thereof.

[0023] In a preferred embodiment of the benzopyrylium dye, the anion An n- is C8~C 25 Alkanesulfonates, preferably C 13 ~C 25 Alkanesulfonates, C8-C 25 Alkyl sulfates, preferably C 13 ~C 25 Alkyl sulfate, bis-(C4-C 25 Alkyl-, C5-C7 cycloalkyl-, C3-C8 alkenyl- or C7-C 11 Aralkyl-)sulfosuccinates, C8-C 25 Alkyl sulfoacetates, C4-C 25 Alkyl and / or C1-C 12 The benzenesulfonate substituted with at least one radical of an alkoxycarbonyl group, and tetraphenylborate, or a combination of at least two thereof, is selected from the group consisting of: benzenesulfonate substituted with at least one radical of an alkoxycarbonyl group; and tetraphenylborate.

[0024] Anion An n- is preferably bis-C4-C 25 Alkyl sulfosuccinates, C4-C 25 It is selected from the group consisting of alkyl-substituted benzenesulfonates and tetraphenylborates.

[0025] Anion An n- is particularly preferably selected from the group consisting of (2-ethylhexyl) sulfosuccinate, dodecylbenzenesulfonate and tetraphenylborate.

[0026] In one particularly preferred embodiment of the benzopyrylium dye, R200, R205, R207 and R208 are hydrogen, A is a -CH2-CH2- bridge, R201 is selected from the group consisting of hydrogen, C1-C4 alkyl, hydroxyl, C1-C4 alkoxy or dialkylamino, where dialkylamino is selected from the group consisting of diethylamino, dimethylamino and diisopropylamino or a combination of at least two thereof, particularly preferably hydrogen; R202 is hydrogen, C1-C4 alkyl, hydroxyl or C1-C4 alkoxy, particularly preferably hydrogen; R203 is hydrogen or forms a -CH=CH-CH=CH- bridge together with R202, particularly preferably hydrogen; R204 is hydrogen or phenyl, particularly preferably hydrogen; R206 is hydrogen, hydroxyl or C1-C4 alkoxy, particularly preferably hydrogen; Anion An n- is C8~C 25 Alkanesulfonates, preferably C 13 ~C 25 Alkanesulfonates, C8-C 25 Alkyl sulfates, preferably C 13 ~C 25 Alkyl sulfate, bis-(C4-C 25 Alkyl-, C5-C7 cycloalkyl-, C3-C8 alkenyl- or C7-C 11 Aralkyl-)sulfosuccinates, C8-C 25 Alkyl sulfoacetate, bis-C4~C 25 Alkyl sulfosuccinates, especially (2-ethylhexyl) sulfosuccinate, C4-C 25 It is selected from the group consisting of alkyl-substituted benzenesulfonates, especially dodecylbenzenesulfonate and tetraphenylborate, especially tetraphenylborate, and particularly preferably (2-ethylhexyl)sulfosuccinate, dodecylbenzenesulfonate and tetraphenylborate.

[0027] A further subject of the present invention relates to a process for preparing benzopyrylium dyes, in particular benzopyrylium dyes according to the invention, comprising a multi-step reaction sequence in which at least the following reaction steps are carried out: A. First reaction step P1.: P1.i. Dissolving the correspondingly selected 2-hydroxyarylcarbonyl derivative together with the corresponding indanone or tetralone derivative in a weak acid, preferably glacial acetic acid; adding a strong acid to the mixture of P1.ii. and P1.i. and heating the mixture, preferably at reflux, until complete conversion; cooling the mixture of P1.iii. and P1.ii. and washing with a non-polar aprotic solvent; P1.iv. Separate the phase insoluble in the non-polar aprotic solvent and dissolve this phase in water. B. Second reaction step P2.: P2.i. Dye anion An n- and a non-polar aprotic solvent to an aqueous solution of P1.iv.; P2.ii. The mixture of P2.i. is stirred (optionally heated) and the aqueous phase containing the salts is removed and drained. Washing the mixture of P2.iii.P2.ii. with water, preferably to an end point; and P2.iv. The solvent is removed (may be done under reduced pressure) and the benzopyrylium dye according to the invention is dried (may be done under reduced pressure).

[0028] If the dye precipitates after the first reaction step P1., it is filtered off, washed with a non-polar aprotic solvent and used as the purified product together with water in the second reaction step P2. If the crude product is insoluble in water, the oily phase containing the crude product is washed with a non-polar aprotic solvent in step P1.iv. and further treated with water in the second reaction step P2.

[0029] The benzopyrylium dyes herein are preferably prepared in a one-pot reaction according to the following reaction scheme: [ka]

[0030] In the one-pot reaction, in the first reaction step P1, in step P1.i., the corresponding 2-hydroxyarylcarbonyl derivative is first dissolved in glacial acetic acid together with the corresponding indanone or tetralone derivative in a 1:1 equivalent ratio. In step P1.ii., a strong acid, preferably with a pKa value of 4 or less, particularly preferably 3 or less, particularly preferably 2 or less, and most preferably 1 or less, such as sulfuric acid, is added slowly, preferably over a period of 1 to 5 hours, and the mixture is heated at reflux to achieve complete conversion. In step P1.iii., after cooling to a temperature of preferably 10 to 40°C, more preferably 20 to 30°C, and particularly preferably 23 to 25°C, the reaction solution is diluted with a nonpolar aprotic solvent, such as methyl tert-butyl ether (MTBE), and vigorously mixed. In step P1.iv., the solvent-insoluble phase is separated and dissolved in water. In the second reaction stage P2., this aqueous solution is mixed in step P2.i. with an alkali metal salt of the dye anion and an ester solvent, such as butyl acetate, to form an ester solvent / water mixture, which is stirred in step P2.ii. with gentle heating, preferably up to 50°C, more preferably up to 40°C. In step P2.iii., the phases are separated and the organic phase is washed with water. After removal of the solvent in step P2.iv., preferably by heating to 40 to 70°C and drying under reduced pressure, preferably at 10 to 50 mbar, the product is obtained as a highly viscous oil.

[0031] According to the above method, if the crude product precipitates as a solid after the first step P1, the crude product is filtered off, washed with a non-polar aprotic solvent such as MTBE, and used as the purified product in the second step together with water.

[0032] According to the above method, if the crude product is insoluble in water, the oily phase containing the crude product is washed with a non-polar aprotic solvent such as MTBE. The product thus purified is further treated with water in a second step P2.

[0033] A further subject of the present invention relates to the use of the benzopyrylium dyes of the present invention in photocurable formulations, preferably as part of a two-component photoinitiator system, in combination with a suitable electron donor to improve the bleachability of the photocurable material. The benzopyrylium dyes of the present invention are preferably utilized after irradiation with actinic radiation to initiate radical polymerization. Electron donors selected from triarylalkylborates, trifluoroalkylborates, tertiary amines, pentacoordinate silicates, and dihydropyridines are preferred for use herein. Preferably, the benzopyrylium dyes of the present invention are used in a three-component photoinitiator system with an electron donor, along with an electron acceptor selected from iodonium salts, sulfonium salts, trichlorotriazines, electron-deficient trihalomethylaromatic compounds, and Katrichky salts, or a mixture of at least two thereof. The electron-deficient trihalomethylaromatic compound is preferably a trichloromethylaromatic compound having a strongly electronegative substituent, such as at least one fluorine atom, as described in Examples 1-9 on pages 19-22 of WO 2015 / 091427. Particularly preferred for use is triarylalkylborate as electron donor with the benzopyrylium dye of the present invention as photoinitiation system.Suitable triarylalkylborate is known from U.S. Pat. No. 1,109,8066, especially from Example 26 on page 47.

[0034] Particularly preferably, these trialkylborate salts are selected from the following structures, where n is selected between 1 and 2, and K + is any monovalent cation. [ka]

[0035] Preferably, the benzopyrylium dyes according to the present invention are used as part of a three-component photoinitiation system in which, in addition to the above-mentioned Type II photoinitiation system, an electron acceptor is added, preferably selected from iodonium salts, sulfonium salts, trichlorotriazines, trichloroaromatic compounds as described in WO 2015 / 091427, or Katrichky salts.

[0036] A further subject of the present invention relates to a photopolymer composition comprising at least a) a matrix polymer, b) a write monomer, c) a non-photopolymerizable component, d) a photoinitiator system (PIS) comprising at least a suitable coinitiator and a benzopyrylium dye according to the invention in the form of a benzopyrylium salt of formula (I), and optionally further e) catalysts, radical stabilizers, solvents, additives and other auxiliaries and / or adjuvants.

[0037] The matrix polymer a), the writing monomer b), the non-photopolymerizable component c), and the PIS d) can all be any of the components known to those skilled in the art for this purpose. The matrix polymer a) is known, for example, from the prior art of U.S. Pat. No. 8,921,012; the writing monomer b) is known, for example, from the prior art of U.S. Patent Application Publication Nos. 2010,086,860, 8,222,314, and 10,241,402; the non-photopolymerizable component c) and the PIS d) are also known, for example, from the prior art of U.S. Pat. Nos. 10,001,703 and 9,146,456; and the optional non-photopolymerizable component c) is known, for example, from the prior art of U.S. Pat. No. 8,999,608. The optional component e) used can be any of the catalysts, radical stabilizers, solvents, additives, and other auxiliaries and / or adjuvants known to those skilled in the art for this purpose.

[0038] Preferred matrix polymers a) with a low refractive index are polyurethanes, which are obtainable, for example, by reaction of a polyol component with a polyisocyanate component.

[0039] Preferably, the writing monomer b) comprises or consists of at least one monofunctional and / or polyfunctional writing monomer. More preferably, the writing monomer b) comprises or consists of at least one monofunctional (meth)acrylate and / or polyfunctional (meth)acrylate writing monomer. Particularly preferably, the writing monomer comprises or consists of at least one monofunctional urethane (meth)acrylate and / or polyfunctional urethane (meth)acrylate.

[0040] The at least one non-photopolymerizable component c) can be any component c) that one skilled in the art would select for a photopolymer composition according to the present invention.

[0041] The at least one photoinitiator system d) can be any photoinitiator system that a person skilled in the art would select for a photopolymer composition according to the present invention. The photoinitiator of component d) is typically a compound that can be activated by actinic radiation to cause polymerization of the writing monomer. Photoinitiators can be distinguished as unimolecular (type I) and bimolecular (type II) initiators. Furthermore, they are distinguished according to their chemical nature as photoinitiators for radical, anionic, cationic, or mixed-mode polymerization.

[0042] Type I photoinitiators (Norrish Type I) for radical photopolymerization upon irradiation generate free radicals by unimolecular bond cleavage. Examples of Type I photoinitiators are triazines, oximes, benzoin ethers, benzil ketals, bis-imidazoles, aroylphosphine oxides, sulfonium salts, and iodonium salts.

[0043] Type II photoinitiators for radical polymerization (Norrish Type II) consist of a dye as a sensitizer and a coinitiator, which undergo a bimolecular reaction when irradiated with light compatible with the dye. First, the dye absorbs a photon and, from its excited state, can undergo a bimolecular reaction with a suitable coinitiator. The latter releases the initiating radical by electron or proton transfer or direct hydrogen abstraction.

[0044] The use of type II photoinitiators is preferred.Further preferred photoinitiator systems d) are in principle described in EP-A-0 223 587 and preferably consist of a mixture of one or more dyes.

[0045] The photopolymer composition preferably further comprises a urethane as an additive of component c), which may in particular be substituted by at least one fluorine atom.

[0046] Similarly, the benzopyrylium dyes according to the present invention can be used in cured photopolymers that are characterized similarly to the photopolymer compositions described above.

[0047] The benzopyrylium dyes according to the invention in the form of benzopyrylium salts of formula (I) and also the associated anions An n- All information regarding the selection of should be used in the same manner as measured values ​​for the benzopyrylium salts of formula (I) according to the invention for use.

[0048] Another subject of the invention is a composition comprising at least the following layers: A. A substrate layer A., ​​which may be part of a further layer structure; B. a photopolymer layer B. comprising a photopolymer composition according to the present invention; and C. an outer layer C., which may optionally be part of a further layer structure; The present invention relates to a layer structure including:

[0049] This photopolymer composition has the same components, component ratios, and properties as the previously described photopolymer composition of the present invention. The layer structure may include additional layers. Preferably, the substrate layer A and the outer layer C have an adhesive layer on at least one of their two surfaces so that the substrate layer A or the outer layer C can be bonded to the polymer layer B or the additional outer layer.

[0050] Another subject of the invention is a composition comprising at least the following layers: A. A substrate layer A., ​​which may be part of a further layer structure; B. A cured photopolymer layer B' produced from the photopolymer composition according to the present invention by curing with light; C. an outer layer C., which may optionally be part of a further layer structure; The present invention relates to a layer structure including:

[0051] This photopolymer composition has the same components, component ratios, and properties as the previously described photopolymer composition according to the present invention. The layer structure may include additional layers. Preferably, the substrate layer A and the outer layer C have an adhesive layer on at least one of their two surfaces, allowing the substrate layer A or the outer layer C to be bonded to the cured polymer layer B' or the additional outer layer.

[0052] Another subject of the present invention relates to a holographic medium comprising a benzopyrylium dye according to the present invention, or a benzopyrylium dye prepared by the method according to the present invention, or a holographic medium comprising a photopolymer composition according to the present invention. Furthermore, a method for producing a holographic medium using the benzopyrylium dye according to the present invention, for example in the form of the above-mentioned photopolymer composition containing the benzopyrylium dye according to the present invention, is also disclosed. The dye according to the present invention or the photopolymer composition according to the present invention can be used to produce a holographic medium, in particular in the form of a film. In this case, a layer of a material or a material assembly transparent to light in the visible and NIR spectral range (transmittance greater than 85% in the wavelength range from 400 to 1200 nm) in the form of a substrate layer A as a support is coated on one or both sides in the dark with a photopolymer composition B, and a covering layer C may be used on one or more photopolymer layers B. Preferred materials or material assemblies for the support in the form of substrate layer A are based on polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene, polypropylene, cellulose acetate, cellulose hydrate, cellulose nitrate, cycloolefin polymers, polystyrene, polyepoxides, polysulfones, cellulose triacetate (CTA), polyamides, polyimides, polymethyl methacrylate, polyvinyl chloride, polyvinyl butyral, or polydicyclopentadiene, or mixtures thereof. More preferably, they are based on PC, PET, and CTA. The material assemblies may be film laminates or coextrusions. Preferred material assemblies are bilayer and trilayer films configured according to one of the following structures: A. / B., A. / B. / A., or A. / B. / C. PC / PET, PET / PC / PET, and PC / TPU (TPU = thermoplastic polyurethane) are particularly preferred. The support material or mass of materials in the form of substrate layer A may be provided with an anti-adhesive, anti-static, hydrophobic or hydrophilic finish on one or both sides, and the material or mass of materials may also be activated, primarily by plasma pretreatment or UV light irradiation.The described modifications are applied to the side facing the photopolymer layer B. so that the photopolymer layer B adheres more strongly to the substrate layer A. or, conversely, can be removed from the substrate layer A. without damage. The modification of the surface of the support in the form of the substrate layer A. facing away from the photopolymer layer B. serves to ensure that the media according to the invention meets the specific mechanical requirements required for processing, for example, in a roll laminator, especially a roll-to-roll process. The outer layer C. preferably has the same material, properties, and composition as the substrate layer A. and is preferably produced by the same method as the substrate layer A.

[0053] Furthermore, a further method for producing a holographic medium using the benzopyrylium dye according to the present invention, particularly in the form of the aforementioned photopolymer composition containing at least a benzopyrylium dye, is disclosed. The method also provides a holographic medium in the form of a film or layer structure. In this case, a substrate layer A, a material or layer of a material assembly transparent to light in the visible and NIR spectral range (transmittance of more than 85% in the wavelength range of 400 to 1200 nm), may be coated on one side by two-dimensional printing in the dark with photopolymer composition B, and one or more photopolymer layers B may be coated with a covering layer C. Any common inkjet technology can be used here. It may also be possible to print photopolymer composition B in a targeted manner only in areas where functionality is required. Preferred materials or material assemblies for the support are based on glass, silicon (in the form of highly polished wafers known from semiconductor technology), polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene, polypropylene, cellulose acetate, cellulose hydrate, cellulose nitrate, cycloolefin polymers, polystyrene, polyepoxides, polysulfones, cellulose triacetate (CTA), polyamides, polymethyl methacrylate, polyvinyl chloride, polyvinyl butyral, or polydicyclopentadiene, or mixtures thereof. More preferably, they are based on PC, PET, and CTA. The material assemblies may be film laminates or coextrusions. Preferred material assemblies are bilayer and trilayer films configured according to one of the following structures: A. / B., A. / B. / A., or A. / B. / C. PC / PET, PET / PC / PET, and PC / TPU (TPU = thermoplastic polyurethane) are particularly preferred. The support material or material assembly may be provided with an anti-adhesive, anti-static, hydrophobic or hydrophilic finish on one or both sides. The described modifications are applied to the side facing the photopolymer layer B so that the photopolymer layer B can be removed from the support in the form of the substrate layer A without damage.The modification of the surface of the support facing away from the photopolymer layer B. serves to ensure that the media according to the present invention meets the specific mechanical requirements required for processing, for example, in a roll laminator, particularly a roll-to-roll process.

[0054] Further preferred are material assemblies of the above type which comprise a light-cured photopolymer layer B', thus forming double and triple films according to the configurations A. / B'., A. / B'. / A. or A. / B'. / C.

[0055] Further disclosed is a method for producing a holographic medium using the benzopyrylium dye according to the present invention, particularly in the form of the aforementioned photopolymer composition containing at least a benzopyrylium dye. The method also provides a holographic medium in the form of a glass (D.) or acrylic (E.) composite. The photopolymer composition is directly embedded between two layers of glass or acrylic in the dark. This is preferably achieved by a method selected from the group consisting of injecting the photopolymer composition into a cavity between two glass or acrylic exteriors, applying it to the glass or acrylic surface by spraying, knife coating, dipping, nozzle, roll, or spin coating, or laminating a free photopolymer film and covering it with a second glass or acrylic exterior. D. / B. / D., D. / B. / E., E. / B. / D., E. / B. / E., D. / B. / A., or E. / B. / A. layer structures are preferred, where D. represents the glass layer and E. represents the acrylic layer. Layers D and E are preferably non-sticky, hydrophobic, or hydrophilic. The described modifications are applied to the side facing photopolymer layer B so that photopolymer layer B adheres more strongly to the surface facing D or E, or conversely, can be removed from the surface without damage. Further preferred are glass or acrylic assemblies of the above type that include a light-cured photopolymer layer B', so that the assembly is formed according to the structure D / B' / D, D / B' / E, E / B' / D, E / B' / E, D / B' / A, or E / B' / A.

[0056] Holographic information in the form of a hologram can be incorporated into such a holographic medium by exposure to light.

[0057] The holographic media according to the invention can be processed by corresponding exposure procedures for optical applications in the NIR and the entire visible and near UV range (350-1500 nm) to obtain holograms, which encompass all holograms that can be recorded by methods known to those skilled in the art.

[0058] Another subject of the invention relates to the holograms that can be obtained from the holographic medium according to the invention.As mentioned above, the holograms can be obtained by suitable exposure of the holographic medium.

[0059] Preferred embodiments of the hologram are selected from the group consisting of off-axis holograms, full-aperture transfer holograms, white-light transmission holograms ("rainbow holograms"), Denisyuk holograms, off-axis reflection holograms, edge-lit holograms, and holographic stereograms. Reflection holograms, Denisyuk holograms, transmission holograms, or combinations of at least two thereof are preferred. Preferably, combinations of these hologram types or multiple holograms of the same type are independently integrated into the same volume of the holographic medium, also known as multiplexing.

[0060] Possible optical functions of holograms that can be produced using photopolymer compositions containing at least one benzopyrylium dye according to the present invention correspond to the optical functions of optical elements such as lenses, mirrors, deflection mirrors, filters, diffusing lenses, diffractive elements, diffusers, waveguides, light guides, projection lenses, and / or masks. Similarly, combinations of these optical functions can be combined independently in a single hologram. Often, these optical elements exhibit frequency selectivity depending on how the hologram is exposed and the dimensions of the hologram.

[0061] Furthermore, the holographic medium may also produce holographic images or representations in the form of holograms, for example as images or image structures for personal portraits, biometric indication in classified documents, or generally for video that can represent digital data including advertising, security labels, brand protection, branding, labels, design elements, decorations, illustrations, collectible cards, photographs, etc., as well as those in combination with the products detailed above. Holographic images may have the impression of a three-dimensional image, but may also represent a continuous image, a short film, or several different objects, depending on the angle of the illuminating (possibly moving) light source, etc.

[0062] Another subject of the invention relates to an optical display comprising a holographic medium according to the invention or a hologram according to the invention.

[0063] Another subject of the invention relates to the use of a photopolymer composition according to the invention for producing a holographic medium or a hologram.

[0064] The above-mentioned features of the holograms that can be produced with the benzopyrylium dyes according to the invention or the photopolymer compositions according to the invention find use, for example but not exclusively, in the fields of eye tracking, sensing, and also LIDAR, as well as augmented reality, head-mounted display, and virtual reality applications in the NIR range.

[0065] Another subject of the invention relates to the use of the holographic medium according to the invention in a medium for producing chip cards, identity cards, 3D images, product protection tags, labels, banknotes or holographic optical elements, in particular for optical displays or for realizing a method selected from the group consisting of eye tracking, sensing, LIDAR, augmented reality, head mounted display, head up display and virtual reality applications, in particular in the near infrared range, and a combination of at least two thereof.

[0066] The holographic medium can be used for recording in-line, off-axis, full aperture transfer, white light transmission, Denisyuk, off-axis reflection, or edge-lit holograms, as well as holographic stereograms, particularly for the generation of optical elements, images, or image representations.

[0067] Holograms are preferably obtainable from the holographic medium according to the invention by exposure to light.

[0068] Working Example: The following examples are used to illustrate the invention without limiting it thereto.

[0069] Measurement method: OH number: The specific OH number was determined in accordance with DIN 53240-2-2007-11.

[0070] NCO values: The specific NCO values ​​(isocyanate content) were determined in accordance with DIN EN ISO 11909-2007-05.

[0071] Measurement of holographic properties DE and Δn of holographic media by two-beam interference in a reflection configuration:

[0072] As shown in Figure 1, a blue DPSS laser beam with an emission wavelength λ of 457 nm in vacuum was converted into a parallel, uniform beam using a spatial filter (SF) and a collimating lens (CL). The final cross sections of the signal and reference beams were fixed by an iris diaphragm (I). The diameter of the iris aperture was 0.4 cm. A polarization-dependent beam splitter (PBS) split the laser beam into two coherent beams with the same polarization. Using a λ / 2 plate, the power of the reference beam was set to 0.5 mW and the power of the signal beam was set to 0.65 mW. The power was determined using a semiconductor detector (D) with the sample removed. The angle of incidence (α0) of the reference beam was -22.0°, and the angle of incidence (β0) of the signal beam was 42.0°. The angles were measured from the normal to the sample toward the beam direction. Therefore, according to Figure 1, α0 has a negative sign and β0 has a positive sign. At the sample (holographic medium), the interference field of the two overlapping beams produced a grating of light and dark fringes perpendicular to the angle bisector of the two beams incident on the sample (a reflection hologram). The fringe spacing Λ in the holographic medium, also called the grating period, was approximately 225 nm (assuming a refractive index of the holographic medium of approximately 1.504).

[0073] Figure 1 shows the holographic test setup used to measure the diffraction efficiency (DE) of the holographic medium. Figure 1 depicts the geometry of the holographic medium tester (HMT) at λ = 457 nm (DPSS laser). M = mirror, S = shutter, SF = spatial filter, CL = collimator lens, λ / 2 = λ / 2 plate, PBS = polarization-sensitive beam splitter, D = detector, I = iris diaphragm, α0 = -22°, β0 = 42° are the angles of incidence of the coherent beam measured outside the sample (outside the holographic medium), and RD = reference direction of the turntable.

[0074] The hologram was written into the holographic medium in the following manner. · Both shutters (S) are open for exposure time t. The holographic medium was then left for 5 minutes with the shutter (S) closed to allow for diffusion of the unpolymerized writing monomer.

[0075] The written hologram was then read out as follows: The shutter for the signal beam remained closed; the shutter for the reference beam was opened; and the iris diaphragm for the reference beam was closed to a diameter of less than 1 mm. This ensured that for all rotation angles (Ω) of the holographic medium, the beam was always completely within the previously written hologram. The turntable was then rotated under computer control through Ω in angular steps of 0.05°. min From Omega max The angle was swept over a range of angles from α0 = -32° to β0 = 32°. Ω was measured from the normal to the sample to the reference direction of the turntable. The reference direction of the turntable was obtained when the angles of incidence of the reference and signal beams during the writing of the hologram had the same absolute value, i.e., α0 = -32° and β0 = 32°. Then, Ω 記録 was = 0°. Therefore, when α0 = -22.0° and β0 = 42.0°, Ω 記録 was 10°. In general, for the interference field during writing ("recording") of a hologram, the following holds:

number

number

number

[0076] Using the method described above, the Bragg curve describing the diffraction efficiency η as a function of the rotation angle Ω of the written hologram was measured and stored in a computer. The transmitted intensity of the zeroth order was also recorded as a function of the rotation angle Ω and stored in a computer.

[0077] The maximum diffraction efficiency of the hologram (DE=η max ), i.e., its peak value is Ω 再生 In some cases, for this purpose it was necessary to change the position of the detector relative to the diffracted beam in order to determine this maximum.

[0078] The refractive index contrast Δn and thickness d of the photopolymer layer (i.e., of the sample or holographic medium) were then determined from the measured Bragg curves and angle graphs of the transmitted intensity using coupled-wave theory (see H. Kogelnik, The Bell System Technical Journal, volume 48, November 1969, number 9, pp. 2909-2947). In this connection, it should be noted that due to the thickness shrinkage that occurs as a result of photopolymerization, the fringe spacing Λ' and fringe orientation (tilt) of the hologram may differ from the fringe spacing Λ and its orientation of the interference pattern. Therefore, the angle α' at which maximum diffraction efficiency is achieved and the corresponding turntable angle Ω are 再生 also, α0 and the corresponding Ω 記録 This changes the Bragg condition, and this change is taken into account in the evaluation process, which is described below.

[0079] All geometric parameters related to the recorded hologram and not related to the interference pattern are shown as primed parameters.

[0080] Regarding the Bragg curve η(Ω) of a reflection hologram by Kogelnik,

number

number

number

number

number

[0081] The still unknown angle β' can be determined from a comparison of the Bragg conditions for the interference field during the hologram writing process and the Bragg conditions during the hologram reconstruction process, assuming that only thickness contraction occurs.

number

[0082] The maximum diffraction efficiency (DE=η max ) is obtained as follows:

number

number

[0083] Since the DE is known, the shape of the theoretical Bragg curve according to Kogelnik is determined only by the thickness d' of the photopolymer layer. Δn is modified via the DE for a given thickness d' so that the measured and theoretical DE always coincide. Here, d' is adjusted until the angular position of the first minimum of the theoretical Bragg curve coincides with the angular position of the first maximum of the transmitted intensity, and until the full width at half maximum (FWHM) of the theoretical Bragg curve and the transmitted intensity coincide.

[0084] When reconstructed by scanning Ω, the orientation of the reflection hologram also rotates, but because the detector for the diffracted light can only cover a finite angular range, the Bragg curve of a wide hologram (small d') is not completely covered by scanning Ω, but rather only the central region, given the appropriate detector placement. Therefore, the shape of the transmission intensity, which is complementary to the Bragg curve, is further used to adjust the layer thickness d'.

[0085] Figure 2 shows plots of the coupled-wave theory Bragg curve η (dashed line), the measured diffraction efficiency (black circles), and the transmitted power (black solid line) versus the angular detuning ΔΩ.

[0086] To determine the mean energy dose of the incident laser beam at which DE reaches a saturation value when writing a hologram, this procedure may be repeated multiple times for different exposure times t on different holographic media for clarity. The mean energy dose E is calculated by the power (P) of the two components of the beam assigned to angles α and β.r = 1.31 mW reference beam and P s = 1.69 mW signal beam), exposure time t, and diameter of the iris diaphragm (0.4 cm) are calculated as follows:

number

[0087] material:

[0088] Solvents, reagents, and all bromoaromatic compounds used were purchased from chemical suppliers. Bromoaromatic compounds were freshly distilled where appropriate. Anhydrous solvents contain less than 50 ppm water.

[0089] Polyol 1 was prepared similarly to Polyol 1 described in WO2015091427 and had an OH number of 56.8.

[0090] Desmodur® N 3900, product of Covestro AG, Leverkusen, Germany, hexanediisocyanate-based polyisocyanate with a proportion of at least 30% iminooxadiazinedione and an NCO content of 23.5%.

[0091] Fomrez® UL-28 urethanization catalyst, commercially available from Momentive Performance Chemicals, Wilton, Connecticut, USA.

[0092] Urethane acrylate 1 (phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl)trisacrylate, [CAS number 1072454-85-3]) was prepared as described in WO2015091427.

[0093] Urethane acrylate 2 (2-({[3-(methylsulfanyl)phenyl]carbamoyl}oxy)-ethylprop-2-enoate, [CAS number 1207339-61-4]) was prepared as described in WO2015091427.

[0094] Additive 1 (bis(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl)-(2,2,4-trimethylhexane-1,6-diyl)biscarbamate [CAS number 1799437-41-4]) was prepared as described in WO2015091427.

[0095] Co-initiator 1 (N-benzyl-N,N-dimethylhexadecylammonium tris-(3-chloro-4-methylphenyl)hexylborate, [CAS number 1702465-82-4]) was prepared from 1-bromo-3-chlorobenzene, diisopropyl-hexylboronic acid ester, and N-benzyl-N,N-dimethylhexadecylammonium chloride as described in WO 2018087064.

[0096] BYK-310 silicone-containing surface additive, product of BYK-Chemie GmbH (Wesel, Germany).

[0097] Dye 1 Benzopyrylium dye 5,6-dihydro-3,10-dimethoxy-7-phenylbenzo[c]xanthylium perchlorate [CAS number 126634-30-8], available from Synthon Chemicals GmbH & Co. KG (Bitterfeld-Wolfen, Germany).

[0098] Dye 2 (1,3,3-trimethyl-2-[2-(1-methyl-2-phenyl-1H-indol-3-yl)ethenyl]-3H-indolium bis(2-ethylhexyl) sulfosuccinate [CAS number 1374689-54-9]) was prepared as described in WO 2012062655.

[0099] Dye 3 2-[2-[4-[(2-chloroethyl)methylamino]phenyl]ethenyl]-1,3,3-trimethyl-3H-indolium bis(2-ethylhexyl) sulfosuccinate [CAS number 153952-28-4] was prepared as described in WO2012062655.

[0100] Synthesis Procedure:

[0101] Preparation Procedure A(R 200 , R 204 , R 205 , R 207 and R 208 =H and any R other than NR2 201 For benzopyrylium salts with: [ka] The corresponding 2-hydroxyarylaldehyde derivative (1.0 equivalent) was dissolved in glacial acetic acid (0.4 M) along with the corresponding tetralone derivative (1.0 equivalent). Sulfuric acid (2.0 equivalents) was slowly added, and the mixture was heated at reflux for 1 hour. After cooling to room temperature, the reaction solution was added to methyl tert-butyl ether (MTBE). The resulting solid was filtered off, and the reaction product was washed with MTBE (twice) and dried under reduced pressure. The reaction product was then dissolved in a butyl acetate / water mixture (1:1) at 50 °C along with the corresponding sodium salt of the dye anion (1.0 equivalent) and stirred vigorously overnight. The phases were separated, and the organic phase was washed with water (deionized, six times). The solvent was removed under reduced pressure, and the residue was dried under reduced pressure to give the product as a thick oil.

[0102] Preparation Procedure B(R 200 , R 203 , R 205 , R 207 and R 208 =H and R 204 For benzopyrylium bis(2-ethylhexyl) sulfosuccinate with Ph: [ka] The corresponding 2-hydroxybenzophenone derivative (1.0 equivalent) is dissolved in glacial acetic acid (0.4 M) along with the corresponding tetralone derivative (1.0 equivalent). Sulfuric acid (2.0 equivalents) is slowly added, and the mixture is heated at reflux for at least 8 hours. After cooling to room temperature, the reaction solution is added to methyl tert-butyl ether (MTBE), precipitating the product as an insoluble oil. The ether phase is separated, and the oily phase is washed several times with MTBE. The product is dissolved in a butyl acetate / water mixture (1:1) with sodium bis(2-ethylhexyl) sulfosuccinate at 50 °C and stirred vigorously overnight. The phases are separated, and the organic phase is washed with water (deionized, 6 times). The solvent is removed under reduced pressure, and the residue is dried under reduced pressure to give the product as a highly viscous oil.

[0103] Preparation procedure C(R 200 , R 202 , R 203 , R 204 , R 205 , R 207 and R 208 =H and R 201 = In the case of benzopyrylium bis(2-ethylhexyl) sulfosuccinate with NEt2: [ka] 4-Diethylaminosalicylaldehyde (1.0 equiv.) was dissolved in glacial acetic acid (0.4 M) along with the corresponding tetralone derivative (1.0 equiv.). Sulfuric acid (2.0 equiv.) was slowly added, and the mixture was heated at reflux for 1 hour. After cooling to room temperature, the reaction solution was added to methyl tert-butyl ether (MTBE), precipitating the product as an insoluble oil. The ether phase was separated, and the product was dissolved in water (deionized). The aqueous phase was washed with MTBE (3 times), and finally, the biphasic mixture was vigorously stirred overnight with a solution of sodium bis(2-ethylhexyl) sulfosuccinate in butyl acetate (0.9 equiv.). The phases were separated, and the organic phase was washed with water (deionized, 6 times). The solvent was removed under reduced pressure, and the residue was dried under reduced pressure to give the product.

[0104] Preparation Procedure D (for photopolymer film / holographic media): 5.85 g of the polyol component 1 was melt-mixed in the dark with 2.16 g of urethane acrylate 1, 6.48 g of urethane acrylate 2, 5.4 g of the fluorinated urethane (additive 1), 0.43 g of coinitiator 1, 0.11 g of each dye, 0.07 g of BYK 310, 0.02 g of Fomrez® UL-28, and 8.4 g of ethyl acetate to obtain a clear solution. Following this, 1.08 g of Desmodur® N 3900 was added and mixing resumed. This solution was placed on a 60 μm thick TAC film on a dark roll-to-roll coating line and coated with a doctor blade to achieve a fresh film thickness of 12-14 μm. The coated film was dried at 120°C for 4 minutes and then protected with a 40 μm thick polyethylene film. The film was then packaged in a light-tight manner.

[0105] [Example]

[0106] Example 1: Preparation of 12,13 dihydro-10-methoxydibenzo[a,h]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 12,13 dihydro-10-methoxydibenzo[a,h]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure A, 2-hydroxynaphthaldehyde was reacted with 6-methoxy-1-tetralone, and sodium bis(2-ethylhexyl) sulfosuccinate was used for ion exchange. A highly viscous red oil (1.81 g, 72% of theoretical yield over two steps) was obtained. Holographic media containing this benzopyrylium dye were prepared according to preparation procedure D.

[0107] 1H NMR(600MHz,CDCl3):δ 10.39(s,1H),9.18(d,J=8.4Hz,1H),8.44(d,J=9.2Hz,1H),8.36(d,J=8.8Hz,1H),8.06(ddd,J=1 1.0,7.5,2.0Hz,2H),7.99(d,J=9.2Hz,1H),7.83(ddd,J=8.1,7.0,1.0Hz,1H),7.12-7.07(m,1H) ,6.96(d,J=2.4Hz,1H),4.25-4.20(m,1H),4.03-3.87(m,7H),3.71(t,J=7.5Hz,2H),3.34-3.25( m,3H),3.14(dd,J=17.6,3.3Hz,1H),1.54-1.48(m,2H),1.34-1.17(m,16H),0.91-0.79(m,12H). Absorption maximum (in acetone): 479-490 nm.

[0108] Example 2: Preparation of 5,6-dihydro-3,9,10-trimethoxybenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 5,6-dihydro-3,9,10-trimethoxybenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure A, 2-hydroxy-4,5-dimethoxybenzaldehyde was reacted with 6-methoxy-1-tetralone, and sodium bis(2-ethylhexyl) sulfosuccinate was used for ion exchange. A highly viscous orange oil (2.3 g, 90% of theoretical yield over two steps) was obtained. Holographic media containing this benzopyrylium dye were prepared according to preparation procedure D.

[0109] 1H NMR(600MHz,CDCl3):δ 9.17(s,1H),8.45(d,J=8.8Hz,1H),7.70(d,J=9.8Hz,2H),7.10(dd,J=8.8,2.5Hz,1H),6.86(d,J=2.4Hz,1H),4.23(dd,J=11.7,3.4Hz,1H), 4.14(s,3H),4.01-3.91(m,10H),3.34-3.24(m,3H),3.17-3.08(m,3H) ,1.53(pd,J=6.0,1.9Hz,2H),1.36-1.19(m,16H),0.90-0.80(m,12H). Absorption maximum (in acetone): 480-492 nm.

[0110] Example 3: Preparation of 10-(diethylamino)-5,6-dihydro-3-methoxybenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 10-(diethylamino)-5,6-dihydro-3-methoxybenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: 6-Methoxy-1-tetralone was reacted according to general preparation procedure C. A viscous purple oil (1.2 g, 76% of theoretical yield over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0111] 1 H NMR(600MHz,CDCl3):δ 8.98(s,1H),8.24(d,J=9.4Hz,1H),8.17(d,J=8.8Hz,1H),7.22(dd,J=9.4,2.5Hz,1H),7.00 (dd,J=8.8,2.5Hz,1H),6.91(dd,J=2.4,0.8Hz,1H),6.86(d,J=2.4Hz,1H),4.22(dd,J=11.9, 3.1Hz,1H),4.06(s,7H),3.64(q,J=7.2Hz,4H),3.38(dd,J=17.6,12.0Hz,1H),3.24-3.16(m, 3H),3.07(dd,J=8.8,6.5Hz,2H),1.57-1.48(m,2H),1.38-1.18(m,22H),0.89-0.83(m,12H). Absorption maximum (in acetone): 543-572 nm.

[0112] Example 4: Preparation of 10-(diethylamino)-5,6-dihydrobenzo[c]xanthylium bis-(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 10-(diethylamino)-5,6-dihydrobenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: 1-Tetralone was reacted according to general preparation procedure C. A viscous purple oil (1.4 g, 64% of theoretical over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0113] 1 H NMR(600MHz,CDCl3):δ 8.93(s,1H),8.22(d,J=9.5Hz,1H),8.16(dd,J=7.8,1.3Hz,1H),7.52(td,J=7.5,1.4Hz,1H),7.46(t d,J=7.6,1.2Hz,1H),7.32(dd,J=7.6,1.2Hz,1H),7.28(dd,J=9.4,2.4Hz,1H),6.96-6.91(m,1H),4. 19(dd,J=11.9,3.2Hz,1H),4.04(s,4H),3.66(q,J=7.2Hz,4H),3.31(dd,J=17.6,11.9Hz,1H),3.20- 3.11(m,3H),3.06(dd,J=8.9,6.6Hz,2H),1.55-1.46(m,2H),1.36-1.16(m,22H),0.89-0.76(m,12H). Absorption maximum (in acetone): 527-554 nm.

[0114] Example 5: Preparation of 5,6-dihydro-3,10-dimethoxy-7-phenylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 5,6-dihydro-3,10-dimethoxy-7-phenylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure B, 2-hydroxy-4-methoxybenzophenone was reacted with 6-methoxy-1-tetralone at 140 °C for 22 hours. A dark red solid (1.8 g, 76% of theoretical over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0115] 1 H NMR(600MHz,CDCl3):δ 8.74(d,J=8.9Hz,1H),8.00(d,J=2.4Hz,1H),7.65-7.61(m,3H),7.42(d,J=9.2 Hz,1H),7.41-7.38(m,2H),7.18(ddd,J=9.2,4.5,2.5Hz,2H),6.85(d,J=2.4Hz, 1H),4.19-4.10(m,4H),4.03-3.88(m,7H),3.24-3.16(m,1H),3.06-3.00(m,4H) ,2.95-2.90(m,1H),1.54-1.48(m,2H),1.38-1.18(m,16H),0.91-0.80(m,12H). Absorption maximum (in acetone): 471-481 nm.

[0116] Example 6: Preparation of 5,6-dihydro-3,10-dimethoxybenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 5,6-dihydro-3,10-dimethoxybenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure A, 4-methoxysalicylaldehyde was reacted with 6-methoxy-1-tetralone, and sodium bis(2-ethylhexyl) sulfosuccinate was used for ion exchange. A red solid (2.0 g, 74% of theoretical yield over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0117] 1H NMR (600 MHz, CDCl): δ 9.21(s,1H),8.48(d,J=8.9Hz,1H),8.16(d,J=9.0Hz,1H),7.69(d,J=2.3Hz, 1H),7.19(dd,J=9.0,2.3Hz,1H),7.09(dd,J=8.9,2.5Hz,1H),6.85(d,J=2.4H z,1H),4.21(dd,J=11.8,3.3Hz,1H),4.09-3.89(m,10H),3.35-3.24(m,3H),3 .17-3.07(m,3H),1.57-1.48(m,2H),1.34-1.17(m,16H),0.89-0.79(m,12H). Absorption maximum (in acetone): 466-479 nm.

[0118] Example 7: Preparation of 5,6-dihydro-3-methoxy-9-methyl-7-phenylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 5,6-dihydro-3-methoxy-9-methyl-7-phenylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure B, 2-hydroxy-5-methylbenzophenone was reacted with 6-methoxy-1-tetralone for 12 hours. A brown solid (0.98 g, 35% of theoretical yield over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0119] 1H NMR(600MHz,CDCl3):δ 8.60(d,J=8.9Hz,1H),8.21(d,J=8.7Hz,1H),7.87(dd,J=8.7,2.0Hz,1H),7.68-7.61(m,3 H),7.48-7.43(m,2H),7.29(dd,J=2.1,1.0Hz,1H),7.14(dd,J=9.0,2.4Hz,1H),6.96(d,J= 2.4Hz,1H),4.02-3.83(m,8H),3.20-3.12(m,3H),3.04(dd,J=8.2,6.0Hz,2H),2.95(dd,J= 17.5,2.9Hz,1H),2.45(s,3H),1.52-1.45(m,2H),1.32-1.17(m,16H),0.87-0.79(m,12H). Absorption maximum (in acetone): 455-464 nm.

[0120] Example 8: Preparation of 5,6-dihydro-3-methoxy-10-methylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 5,6-dihydro-3-methoxy-10-methylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure A, 2-hydroxy-4-methylbenzaldehyde was reacted with 6-methoxy-1-tetralone, and sodium bis(2-ethylhexyl) sulfosuccinate was used for ion exchange. A viscous brown oil (1.7 g, 66% of theoretical yield over two steps) was obtained. Holographic media containing this benzopyrylium dye were prepared according to preparation procedure D.

[0121] 1H NMR(600MHz,CDCl3):δ 9.56(d,J=1.0Hz,1H),8.33(dd,J=8.6,6.0Hz,2H),7.82(d,J=1.5Hz,1H),7.63-7.59( m,1H),7.08(dd,J=8.9,2.5Hz,1H),6.95(dd,J=2.4,1.1Hz,1H),4.17(ddd,J=11.8,3.3 ,0.7Hz,1H),4.05-3.88(m,7H),3.50-3.46(m,2H),3.30-3.20(m,3H),3.10(dd,J=17. 5,3.3Hz,1H),2.68(s,3H),1.58-1.49(m,2H),1.35-1.20(m,16H),0.90-0.82(m,12H). Absorption maximum (in acetone): 458-463 nm.

[0122] Example 9: Preparation of 12,13-dihydrodibenzo[a,h]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 12,13-dihydrodibenzo[a,h]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure A, 2-hydroxynaphthaldehyde was reacted with 1-tetralone, and sodium bis(2-ethylhexyl) sulfosuccinate was used for ion exchange. An orange solid (0.84 g, 49% of theoretical value over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0123] 1H NMR(600MHz,CDCl3):δ 10.71(s,1H),9.28(d,J=8.3Hz,1H),8.54(d,J=9.2Hz,1H),8.37(dd,J=7.9,1.2Hz,1H),8.12-8.0 3(m,3H),7.85(ddd,J=8.1,7.1,1.0Hz,1H),7.73(td,J=7.5,1.3Hz,1H),7.62-7.56(m,1H),7.49( d,J=7.6Hz,1H),4.23-4.19(m,1H),4.04-3.88(m,4H),3.77(dd,J=8.3,6.9Hz,2H),3.34-3.25(m, 3H),3.13(dd,J=17.5,3.3Hz,1H),1.52(p,J=5.7Hz,2H),1.34-1.16(m,16H),0.91-0.78(m,12H). Absorption maximum (in acetone): 460-462 nm.

[0124] Example 10: Preparation of 5,6-dihydro-3-methoxy-7-phenylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 5,6-dihydro-3-methoxy-7-phenylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure B, 2-hydroxybenzophenone was reacted with 6-methoxy-1-tetralone for 8 hours. A highly viscous, dark orange oil (0.84 g, 27% of theoretical yield over two steps) was obtained. Holographic media containing this benzopyrylium dye were prepared according to preparation procedure D.

[0125] 1H NMR(600MHz,CDCl3):δ 8.65(d,J=8.9Hz,1H),8.31(d,J=8.5Hz,1H),8.07(ddd,J=8.6,7.0,1.5Hz,1H),7 .69-7.61(m,4H),7.59(dd,J=8.3,1.4Hz,1H),7.50-7.46(m,2H),7.19(dd,J=8.9, 2.4Hz,1H),6.97(d,J=2.3Hz,1H),4.12-4.05(m,1H),4.05-3.85(m,7H),3.18-3.0 6(m,5H),2.98-2.92(m,1H),1.54-1.47(m,2H),1.36(s,16H),0.91-0.80(m,12H). Absorption maximum (in acetone): 455-463 nm.

[0126] Example 11: Preparation of 5,6-dihydro-3-methoxy-9-methylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate and preparation of holographic media containing 5,6-dihydro-3-methoxy-9-methylbenzo[c]xanthylium bis(2-ethylhexyl)sulfosuccinate: According to general preparation procedure A, 2-hydroxy-5-methylbenzaldehyde was reacted with 6-methoxy-1-tetralone, and sodium bis(2-ethylhexyl) sulfosuccinate was used for ion exchange. A brown solid (2.2 g, 86% of theoretical yield over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0127] 1H NMR(600MHz,CDCl3):δ 9.51(d,J=1.1Hz,1H),8.36(d,J=8.9Hz,1H),8.16(t,J=1.5Hz,1H),7.92(d,J=8.7Hz,1H) ,7.84(dd,J=8.8,2.1Hz,1H),7.08(dd,J=8.9,2.5Hz,1H),6.96(d,J=2.4Hz,1H),4.18(dd, J=11.8,3.3Hz,1H),4.10-3.88(m,7H),3.53-3.48(m,2H),3.30-3.21(m,3H),3.10(dd,J= 17.5,3.3Hz,1H),2.60(s,3H),1.56-1.49(m,2H),1.36-1.20(m,16H),0.91-0.81(m,12H). Absorption maximum (in acetone): 455-462 nm.

[0128] Example 12: Preparation of 5,6-dihydro-3,10-dimethoxybenzo[c]xanthylium dodecylbenzenesulfonate and preparation of holographic medium containing 5,6-dihydro-3,10-dimethoxybenzo[c]xanthylium dodecylbenzenesulfonate: According to general preparation procedure A, 4-methoxysalicylaldehyde was reacted with 6-methoxy-1-tetralone, and sodium dodecylbenzenesulfonate was used for ion exchange. A highly viscous reddish-brown oil (0.41 g, 33% of theoretical value over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0129] 1H NMR(600MHz,CDCl3):δ 9.62(s,1H),8.48(d,J=8.9Hz,1H),8.38(d,J=9.0Hz,1H),7.86(d,J=7.7 Hz,2H),7.65-7.62(m,1H),7.34(dd,J=9.0,2.4Hz,1H),7.08(s,3H),6.90 (d,J=2.5Hz,1H),4.10(s,3H),3.98(s,3H),3.42(t,J=7.6Hz,2H),3.16(t ,J=7.6Hz,2H),1.52-1.44(m,1H),1.32-1.01(m,18H),0.88-0.79(m,6H). Absorption maximum (in acetone): 472-481 nm.

[0130] Example 13: Preparation of 5,6-dihydro-3,10-dimethoxybenzo[c]xanthylium tetraphenylborate and preparation of holographic media containing 5,6-dihydro-3,10-dimethoxybenzo[c]xanthylium tetraphenylborate: According to general preparation procedure A, 4-methoxysalicylaldehyde was reacted with 6-methoxy-1-tetralone, and sodium tetraphenylborate was used for ion exchange. An orange solid (0.41 g, 33% of theoretical value over two steps) was obtained. A holographic medium containing this benzopyrylium dye was prepared according to preparation procedure D.

[0131] 1 H NMR(600MHz,CDCl3):δ 8.10(d,J=8.9Hz,1H),7.50-7.43(m,9H),7.19(dd,J=8.9,2.4Hz,1H),7.16(d,J=2.4Hz,1H),6.99-6.92(m,10H), 6.85(d,J=2.5Hz,1H),6.78-6.74(m,4H),3.98(s,3H),3.98(s,3H),2.91(t,J=7.6Hz,2H),2.70(t,J=7.6Hz,2H). Absorption maximum (in acetone): 471-482 nm.

[0132] Non-Inventive Example 1 (NIE-1): Preparation of Holographic Media Containing 5,6-Dihydro-3,10-dimethoxy-7-phenylbenzo[c]xanthylium Perchlorate: According to preparation procedure D, a holographic medium containing dye 1 described above was prepared.

[0133] Non-Inventive Example 2 (NIE-2): Preparation of Holographic Media Containing 1,3,3-Trimethyl-2-[2-(1-methyl-2-phenyl-1H-indol-3-yl)ethenyl]-3H-indolium Bis(2-ethylhexyl) Sulfosuccinate: According to preparation protocol D, a holographic medium containing dye 2 described above was prepared.

[0134] Non-Inventive Example 3 (NIE-3): Preparation of Holographic Media Containing 2-[2-[4-[(2-chloroethyl)methylamino]phenyl]ethenyl]-1,3,3-trimethyl-3H-indolium bis(2-ethylhexyl)sulfosuccinate: According to preparation procedure D, a holographic medium containing dye 3 described above was prepared.

[0135] Evaluation of dyes of the present invention and dyes not of the present invention: One requirement for the photopolymer films produced herein is the highest possible transmittance across the entire visible spectrum, from 400 nm to 800 nm. The higher the transmittance, the better the bleachability. Another requirement for the photopolymer films produced herein is optical and chemical homogeneity, i.e., the absence of haze. If no haze or optical inhomogeneity can be detected by optical inspection of the photopolymer film, the dye being tested has potential for use in holographic media.

[0136] To evaluate and compare the bleachability of photopolymer compositions, holographic media were tested in exactly the same way. For each example, the sample was bleached by blanket exposure to a metal halide lamp for 180 seconds, and the transmission spectra were subsequently recorded from 400 nm to 800 nm. The bleachability of photopolymer films containing various benzopyrylium dyes was calculated using the experimentally recorded transmission spectra using the following equation:

number

[0137] The results show that the required properties of bleachability and optical clarity / uniformity of the photopolymer are achieved using the benzopyrylium dyes according to the present invention. The bleachability values ​​of both the novel and inventive benzopyrylium dyes (Examples 1 to 14) are lower than the bleachability values ​​of the two non-inventive cyanine / hemicyanine dyes, Examples NIE-2 and NIE-3. Furthermore, no turbidity or optical inhomogeneity was observed in any of the inventive examples, except for Example NIE-1, which contains a benzopyrylium cation but is combined with a perchlorate anion and is therefore not in accordance with the present invention.

[0138] Non-inventive examples NIE1, NIE2 and NIE3 fail in at least one required property and are therefore not suitable to provide the required properties.

[0139] Furthermore, as an example, the holographic performance Δn of some films was exemplarily tested by the above-mentioned measurement of photopolymer films by two-beam interference in a reflection configuration, and the measurement results are summarized in Table 2 below. [Table 2]

[0140] Δn from Table 2 max Based on the results of the measurements, it is clear that the new benzopyrylium dyes can be used very well in photopolymers and holographic media in combination with trialkylarylborate salts in two-component photoinitiator systems. The holographic performance was measured using the Δn max Measurements and comparison with NIE-2 show that the results are at least as good as those achievable with known cyanine dyes.

Claims

1. A benzopyrylium dye of formula (I) 【Chemical 1】 During the ceremony, R ２００ , R ２０１ , R ２０２ , R ２０３ , R ２０４ , R ２０５ , R ２０６ , R ２０７ and R ２０８ are each independently hydrogen, alkyl, cycloalkyl, aralkyl, aryl, (het)aryl, hydroxyl, alkoxy or dialkylamino, A is -CH ２ - or -CH ２ -CH ２ - is cross-linked, Anion An ｎ－ has a molecular weight of 200 g / mol or more, does not contain halogen atoms, and n is 1 to 3; Benzopyrylium dyes.

2. R ２００ , R ２０５ , R ２０７ and R ２０８ is hydrogen and A is a-CH ２ -CH ２ - is cross-linked, R ２０４ is hydrogen, C １ ~C ４ 2. The benzopyrylium dye of claim 1, wherein the radical is selected from the group consisting of alkyl, or optionally substituted (het)aryl radicals.

3. R ２００ , R ２０５ , R ２０７ and R ２０８ is a hydrogen atom, and A is -CH ２ -CH ２ - is cross-linked, R ２０１ is hydrogen, C １ ~C ４ Alkyl, hydroxyl, C １ ~C ４ alkoxy or dialkylamino, wherein the dialkylamino is selected from the group consisting of diethylamino, dimethylamino, diisopropylamino, a 6-membered saturated ring bonded through the N of the amino group, which may further contain N or O and may be substituted with any non-ionic radical, or a combination of at least two thereof; R ２０２ is hydrogen, C １ ~C ４ Alkyl, hydroxyl or C １ ~C ４ is an alkoxy; R ２０３ is hydrogen, or R ２０２ together with forming a —CH═CH—CH═CH— bridge, R ２０４ is hydrogen, C １ ~C ４ is an alkyl or optionally substituted (het)aryl radical, R ２０６ is hydrogen, hydroxyl or C １ ~C ４ 3. The benzopyrylium dye of claim 1, which is an alkoxy.

4. The anion An ｎ－ But C ８ ~C ２５ Alkanesulfonates, preferably C １３ ~C ２５ Alkanesulfonates, C ９ ~C ２５ Alkanoate, C ９ ~C ２５ Alkenoate, C ８ ~C ２５ Alkyl sulfates, preferably C １３ ~C ２５ Alkyl sulfate, C ８ ~C ２５ Alkenyl sulfates, preferably C １３ ~C ２５ Alkenyl sulfates, polyether sulfates based on at least 5 equivalents of ethylene oxide or 5 equivalents of propylene oxide, bis-(C ４ ~C ２５ Alkyl-, C ５ ~C ７ Cycloalkyl-, C ３ ~C ８ alkenyl- or C ７ ~C １１ Aralkyl-) sulfosuccinate, C ８ ~C ２５ Alkyl sulfoacetate, C ４ ~C ２５ Alkyl and / or C １ ~C １２ benzenesulfonate substituted with at least one radical of an alkoxycarbonyl group, nitro, cyano, hydroxyl, C １ ~C ２５ Alkyl, C １ ~C １２ Alkoxy, amino or C １ ~C １２ Naphthalene or biphenyl sulfonate optionally substituted with alkoxycarbonyl, nitro, cyano, hydroxyl, C １ ~C ２５ Alkyl, C １ ~C １２ Alkoxy or C １ ~C １２ Benzene-, naphthalene- or biphenyl disulfonate optionally substituted with alkoxycarbonyl, dinitro, C ６ ~C ２５ Alkyl, C ４ ~C １２ 4. Benzopyrylium dye according to any one of claims 1 to 3, characterized in that it is selected from the group consisting of alkoxycarbonyl-, benzoyl- or toluoyl-substituted benzoates, or mixtures of at least two thereof.

5. The anion An ｎ－ But C ８ ~C ２５ Alkanesulfonates, preferably C １３ ~C ２５ Alkanesulfonates, C ８ ~C ２５ Alkyl sulfates, preferably C １３ ~C ２５ Alkyl sulfate, bis-(C ４ ~C ２５ Alkyl-, C ５ ~C ７ Cycloalkyl-, C ３ ~C ８ alkenyl- or C ７ ~C １１ Aralkyl-) sulfosuccinate, C ８ ~C ２５ Alkyl sulfoacetate, C ４ ~C ２５ Alkyl and / or C １ ~C １２ 5. Benzopyrylium dye according to claim 1, characterized in that it is selected from the group consisting of benzenesulfonates substituted with at least one radical of an alkoxycarbonyl group, and tetraphenylborate, or a combination of at least two of them.

6. 10. A method for preparing a benzopyrylium dye, in particular a benzopyrylium dye according to any one of claims 1 to 5, comprising a multi-step reaction sequence, in which A. In the first reaction stage P1., at least the following steps are carried out: P1. i. Dissolving a correspondingly selected 2-hydroxyarylcarbonyl derivative together with a corresponding indanone derivative or tetralone derivative in a weak acid; P1.ii. adding a strong acid and heating the mixture of P1.i.; cooling the mixture of P1.iii. and P1.ii. and washing with a non-polar aprotic solvent; P1.iv. Separating the phase insoluble in the non-polar aprotic solvent and dissolving this phase in water; Run B. In a second reaction stage P2, at least the following steps are carried out: P2. i. The dye anion An ｎ－ and a non-polar aprotic solvent to an aqueous solution of P1.iv., P2.ii. Stirring the mixture of P2.i. (optionally heating) and removing and discharging the aqueous phase containing said salts; Washing the mixture of P2.iii.P2.ii. with water, preferably to an end point; and P2. iv. removing the solvent (optionally under reduced pressure) and drying the benzopyrylium dye (optionally under reduced pressure); To execute method.

7. Use of a benzopyrylium dye according to any one of claims 1 to 5 or prepared as claimed in claim 6 in a photohardenable formulation in combination with an electron donor to improve the bleachability of the photohardenable material.

8. 1. A photopolymer composition comprising: a) a matrix polymer; b) a write monomer; c) a non-photopolymerizable component; d) a photoinitiator system comprising at least a suitable coinitiator and a benzopyrylium dye according to any one of claims 1 to 5 or prepared as claimed in claim 6.

9. At least the following layers: A. A substrate layer A., ​​which may be part of a further layer structure; B. a photopolymer layer comprising the photopolymer composition of claim 8; and C. Optionally, an outer layer C., which may be part of a further layer structure; A layer structure comprising:

10. At least the following layers: A. A substrate layer A., ​​which may be part of a further layer structure; B'. an exposed photopolymer layer B'. prepared from the photopolymer composition of claim 8 by exposure to light; and C. Optionally, an outer layer C., which may be part of a further layer structure; A layer structure comprising:

11. 11. A holographic medium comprising a benzopyrylium dye according to any one of claims 1 to 5 or prepared as claimed in claim 6, or a photopolymer composition according to any one of claims 8 to 10, or obtainable using a photopolymer composition according to any one of claims 8 to 10.

12. A hologram obtained from a holographic medium according to claim 10 or 11.

13. 13. The hologram of claim 12, wherein the hologram is selected from the group consisting of reflection, transmission, in-line, off-axis, full aperture transfer, white light transmission, Denisyuk, off-axis reflection or edge-lit holograms, and holographic stereograms, preferably reflection, transmission or edge-lit holograms, or a combination of at least two thereof.

14. 14. An optical display comprising a holographic medium according to claim 11 or a hologram according to claim 12 or 13.

15. 10. Use of the photopolymer composition of claim 8 for making a holographic medium or hologram.

16. 13. Use of the holographic medium according to claim 11 or 12 in a medium for producing a chip card, an identity card, a 3D image, a product protection tag, a label, a banknote or a holographic optical element, in particular an optical display, or for realizing a method selected from the group consisting of eye tracking, sensing, LIDAR, augmented reality, head mounted display, head up display and virtual reality applications, in particular in the near infrared range, and a combination of at least two thereof.

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