Specific benzopyranium salts as dyes for photopolymer compositions

Abstract

The present invention relates to a benzopyranium dye # imgabs0 # wherein R200, R201, R202, R203, R204, R205, R206, R207 and R208 are each independently of one another hydrogen, a C1 to C16 alkyl group, a C4 to C7 cycloalkyl group, a C7 to C16 aralkyl group, a C6 to C10 (hetero) aryl group, a hydroxyl group, a C1 to C6 alkoxy group or a dialkylamino group, wherein the dialkylamino group is selected from the group consisting of diethylamino, dimethylamino, diisopropylamino, a six-membered saturated ring (which may additionally contain N or O and may be substituted by any non-ionic group) linked by the N of the amino group, or a combination of at least two thereof, and / or R200 and R201 or R201 and R202 or R202 and R203 and / or R205 and R206 and / or R206 and R207 each form together independently of one another-CH = CH-CH = CH-bridge, a is-CH2-or-CH2-CH2-bridge, wherein the anion Ann-has a molecular weight of > = 200 g / mol and is free of halogen atoms.

Description

[0001] The present invention relates to benzopyrylium dyes in the form of benzopyrylium salts, which can be used in particular as dyes in photopolymer compositions for holographic media. Furthermore, the synthesis of specific benzopyrylium salts is disclosed, as well as photopolymer compositions comprising at least a matrix polymer, a writing monomer and a photoinitiator system (PIS), wherein the PIS comprises at least one benzopyrylium salt according to the invention as a dye, holographic media comprising a matrix polymer, a writing monomer and a PIS, wherein the PIS comprises at least one benzopyrylium salt according to the invention as a dye, and layer structures and displays comprising the holographic media according to the invention, which are respectively the subject matter of the present invention.

[0002] A variety of different photopolymer compositions are known in the prior art. For example, WO 2008 / 125229 describes a photopolymer composition and a photopolymer obtainable therefrom, which comprises a polyurethane matrix polymer, one or more acrylate-based writing monomers and a PIS containing a co-initiator and at least one dye. In the use of photopolymers, the refractive index modulation Δn produced by holographic exposure plays a decisive role. In holographic exposure, the interference field consisting of a signal beam and a reference beam (in the simplest case, the interference field of two plane waves) is mapped into a refractive index grating by local photopolymerization of a writing monomer (e.g. a high-refractive-index acrylate) at high-intensity positions in the interference field. The refractive index grating in the photopolymer (hologram) contains all the information of the signal beam. By irradiating the hologram only with a reference beam, the signal can then be reconstructed again. The intensity of the signal reconstructed in this way relative to the intensity of the irradiated reference light is called the diffraction efficiency, hereinafter also simply referred to as DE, the English term "Diffraction Efficiency".

[0003] In the simplest case of a hologram generated by the superposition of two plane waves, the DE is the ratio of the intensity of the diffracted light to the sum of the intensities of the undiffracted and diffracted light at the time of reconstruction. The higher the DE, the more efficient the hologram is in terms of the amount of reference light required to visualize the signal at a defined brightness. However, for many holographic applications of photopolymer compositions and the holographic media produced therefrom, it is not only the holographic properties that play an important role; it is also crucial that the media have excellent bleaching properties, i.e. high transmittance over the entire visible spectrum from 400 nm to 800 nm. This is largely dependent on the dyes used in the photoinitiator system of the photopolymer composition.

[0004] Dyes suitable for photopolymers have been widely described; for example, EP 2638544 describes various types of cationic dyes which can be used in photopolymer compositions as suitable sensitizers in interaction with co-initiators such as triarylalkylborates. In addition to the above-mentioned good bleaching properties, the main requirements for such dyes are rapid initiation of free radical polymerization by electron or energy transfer using suitable co-initiators and good compatibility with the other components of the photopolymer composition to avoid the formation of inhomogeneities or turbidity in the photopolymer. According to EP 2638544, the following dye classes are very suitable for photopolymers: acridine dyes, xanthene dyes, thioxanthene dyes, phenazine dyes, phenoxazine dyes, phenothiazine dyes, tri(hetero)arylmethane dyes, in particular diamino- and triamino(hetero)arylmethane dyes, mono-, di- and tri-methylcyanine dyes, semi-cyanine dyes, external cationic part-cyanine dyes, external cationic neutral cyanine dyes, zero methine dyes, in particular naphtholactam dyes, streptocyanin dyes. Such dyes are also described, for example, in H. Berneth, Ullmann's Encyclopedia of Industrial Chemistry, Azine Dyes, Wiley-VCH Verlag, 2008, H. Berneth, Ullmann's Encyclopedia of Industrial Chemistry, Methine Dyes and Pigments, Wiley-VCH Verlag, 2008, T. Gessner, U. Mayer, Ullmann's Encyclopedia of Industrial Chemistry, Triarylmethane and Diarylmethane Dyes, Wiley-VCH Verlag, 2000.

[0005] However, it has been found that, although these known dyes can achieve very good holographic properties, the bleachability criteria are not yet satisfactorily met.

[0006] Therefore, it is an object of the present invention to provide dyes which at least partially overcome at least one of the disadvantages described above.In addition, it is an object of the present invention to provide photopolymer compositions of the above type which, after bleaching with the aid of a suitable radiation source, provide particularly high transmittance over the entire visible spectrum.

[0007] Surprisingly, it has been found that the use of specific benzopyrylium salts as dyes in photopolymer compositions of the abovementioned type makes it possible to achieve higher transmittances in the entire visible spectral range from 400 nm to 800 nm than with dyes known hitherto (eg from EP 2638544).

[0008] The first subject of the present invention relates to benzopyrylium dyes of formula (I)

[0009]

[0010] in

[0011] R 200 , R 201 , R 202 , R 203 , R 204 , R 205 , R 206 , R 207 and R 208 Each independently of one another is hydrogen, alkyl, preferably C1 to C 16 Alkyl, particularly preferably C1 to C 10 Alkyl, more preferably C1 to C6 alkyl, especially preferably C1 to C4 alkyl, most preferably methyl; cycloalkyl, preferably C4 to C7 cycloalkyl, especially preferably C5 to C6 cycloalkyl, aralkyl, preferably C7 to C 16 Arylalkyl, particularly preferably C8 to C 12 Aralkyl, aryl, preferably phenyl, (hetero)aryl, preferably C6 to C 10 (hetero)aryl, hydroxy, alkoxy, preferably C1 to C6 alkoxy, particularly preferably methoxy, or dialkylamino,

[0012] A is -CH2- or -CH2-CH2- bridge,

[0013] And the anion An n- The molecular weight of the anion An is ≥ 200 g / mol and does not contain halogen atoms, wherein n is 1 to 3. Further preferably, the anion An n- The molecular weight is ≥250 g / mol, more preferably ≥300 g / mol, and particularly preferably ≥350 g / mol. – The molecular weight is ≧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 especially preferably ≧350 g / mol to 700 g / mol.

[0014] Preferably, R 200 With R 201 or R 201 With R202 or R 202 With R 203 or R 205 With R 206 or R 206 With R 207 Independently of one another, they together form a -CH=CH-CH=CH- bridge.

[0015] Preferably, the (hetero)aryl group is an aryl group substituted at least one position by a heteroatom (eg, O, N, P, S or a combination thereof).

[0016] Preferably, the dialkylamino group is preferably a five-membered or six-membered saturated ring connected via the N of the amino group, which may additionally contain N or O and / or may be substituted by a nonionic group. The nonionic group is preferably selected from an alkyl group, an alkoxy group, a hydroxyl group, a thiol group, an aryl group, a (hetero)aryl group, an amine group, an amide group or a combination of at least two thereof.

[0017] Surprisingly, it has been shown that when photopolymer compositions contain at least one dye of the formula (I), the photopolymers have, in addition to high DE and Δn values, rapid initiation of free-radical polymerization and high compatibility with the other components of the photopolymer composition, particularly good bleaching properties.

[0018] In a 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 -CH2-CH2- bridge. Preferably, R 201 , R 202 , R 203 and R 206 are independently selected from hydrogen, C1 to C 16 Alkyl, C4 to C7 cycloalkyl, C7 to C 16 Aralkyl, C6 to C 10 (hetero)aryl, hydroxy, C1 to C6 alkoxy or dialkylamino group, R 204 is a group selected from hydrogen, C1 to C4 alkyl or an optionally substituted (hetero)aryl group, or R 201 With R 202 or R 202 With R 203 Together they form a -CH=CH-CH=CH- bridge. The dialkylamino group is preferably selected from diethylamino, dimethylamino, diisopropylamino, a six-membered saturated ring connected via the N of the amino group (which may contain additional N or O and may be substituted by nonionic arbitrary groups), or a combination of at least two thereof.

[0019] In a particularly preferred embodiment of the benzopyrylium dye of formula (I), R 200, R 205 , R 207 and R 208 is hydrogen, A is a -CH2-CH2- bridge, and R 201 is selected from hydrogen, C1 to C4 alkyl, hydroxy, C1 to C4 alkoxy and dialkylamino, wherein the dialkylamino is selected from diethylamino, dimethylamino, diisopropylamino, a six-membered saturated ring connected through the N of the amino group (which may additionally contain N or O and may be substituted by any nonionic group) or a combination of at least two thereof, R 202 is hydrogen, C1 to C4 alkyl, hydroxyl or C1 to C4 alkoxy, R 203 is hydrogen or with R 202 Together they form a -CH=CH-CH=CH- bridge, R 204 is hydrogen, C1 to C4 alkyl, or optionally substituted (hetero)aryl, and R 206 is hydrogen, hydroxy or C1 to C4 alkoxy.

[0020] Further preferably, in a preferred embodiment of the benzopyrylium dye of formula (I), R 201 is a group selected from hydrogen, methyl, ethyl, methoxy, ethoxy, dimethylamino and diethylamino.

[0021] The following benzopyrylium dyes (III) to (VIII) are particularly preferred:

[0022]

[0023] Preferably, the anion An of the benzopyrylium cation n- (where n=1) is an anion with a molecular weight ≥200 g / mol, selected from an optionally substituted phosphate, an optionally substituted phosphonate, an optionally substituted sulfonimide, an optionally substituted organic borate (e.g., a tetraaryl borate, a triarylalkyl borate or a cyanotriaryl borate), an optionally substituted alkyl or alkenyl sulfate, an optionally substituted monosulfonate or disulfonate (e.g., a sulfosuccinate) or an optionally substituted organic monocarboxylate or dicarboxylate.

[0024] In a preferred embodiment of the benzopyrylium dye, the anion An n- Selected from C8 to C 25 Alkyl sulfonate, preferably C 13 To C 25 Alkyl sulfonate, C9 to C 25 Alkanoate, C9 to C 25 Olenate, C8 to C 25 Alkyl sulfate, preferably C 13 To C 25 Alkyl sulfate, C8 to C 25 Alkenyl sulfate, preferably C13 To C 25 Alkenyl sulfate, based on at least 5 equivalents of ethylene oxide or 5 equivalents of propylene oxide, polyether sulfate, di-C4 to C 25 Alkyl-, C5 to C7 cycloalkyl-, C3 to C8 alkenyl- or C7 to C 11 Arylalkyl sulfosuccinate, C8 to C 25 Alkyl sulfoacetate, replaced by at least one selected from C4 to C 25 Alkyl and / or C1 to C 12 Benzenesulfonate substituted with an alkoxycarbonyl group, optionally with nitro, cyano, hydroxyl, C1 to C 25 Alkyl, C1 to C 12 Alkoxy, amino or C1 to C 12 Alkoxycarbonyl-substituted naphthalenesulfonate or biphenylsulfonate, optionally substituted with nitro, cyano, hydroxyl, C1 to C 25 Alkyl, C1 to C 12 Alkoxy or C1 to C 12 Alkoxycarbonyl-substituted benzene disulfonate, naphthalene disulfonate or biphenyl disulfonate, replaced by dinitro, C6 to C 25 Alkyl, C4 to C 12 Alkoxycarbonyl, benzoyl or methylbenzoyl substituted benzoate.

[0025] Furthermore, the anion is preferably selected from the group consisting of naphthalene dicarboxylic acid anions, diphenyl ether disulfonate anions, sulfonated or sulfated, optionally at least monounsaturated, C8 to C8 aliphatic alcohols or glycerol. 25 Anions of fatty acid esters, C3 to C 12 Bis(sulfo-C2 to C6 alkyl) ester anion of alkanedicarboxylic acid, bis(sulfo-C2 to C6 alkyl) ester anion of itaconate, 18 Alkanecarboxylic acid (sulfo-C2 to C6 alkyl) ester anion, acrylic acid or methacrylic acid (sulfo-C2 to C6 alkyl) ester anion, tricatechol phosphate anion, tetraphenylborate anion, cyanotriphenylborate anion, tetraphenoxyborate anion, C4 to C 12 Alkyltriphenylborate anions (whose phenyl or phenoxy group may be substituted by C1 to C4 alkyl and / or C1 to C4 alkoxy), C4 to C 12 Alkyl trinaphthyl borate anion, tetra-C1 to C 20 Alkoxy borate anions, singly or doubly negatively charged 7,8- or 7,9-dicarbonundecaborate anions (whose B and / or C atoms are optionally substituted by one or two C1 to C 12 alkyl or phenyl substituted), a dodecahydrodicarbonate dodecaborate anion with a doubly negative charge or a B-C1 to C 12Alkyl-C-phenyl dodecahydrodicarbonadecaborate anion, or a mixture of at least two thereof.

[0026] In a preferred embodiment of the benzopyrylium dye, the anion An n- Selected from C8 to C 25 Alkyl sulfonate, preferably C 13 To C 25 Alkyl sulfonate, C8 to C 25 Alkyl sulfate, preferably C 13 To C 25 Alkyl sulfate, di-C4 to C 25 Alkyl-, C5 to C7 cycloalkyl-, C3 to C8 alkenyl- or C7 to C 11 Arylalkyl sulfosuccinate, C8 to C 25 Alkyl sulfoacetate, replaced by at least one selected from C4 to C 25 Alkyl and / or C1 to C 12 The alkoxycarbonyl group is substituted with benzenesulfonate and tetraphenylborate, or a combination of at least two thereof.

[0027] Anion n- Preferably selected from di-C4 to C 25 Alkyl sulfosuccinate, C4 to C 25 Alkyl substituted benzenesulfonates and tetraphenylborates.

[0028] Anion n- Particularly preferred is selected from (2-ethylhexyl)sulfosuccinate, dodecylbenzenesulfonate and tetraphenylborate.

[0029] In a particularly preferred embodiment of the benzopyrylium dye, R200, R205, R207 and R208 are hydrogen, A is a -CH2-CH2-bridge, and wherein

[0030] R201 is selected from hydrogen, C1 to C4 alkyl, hydroxy, C1 to C4 alkoxy or dialkylamino, wherein the dialkylamino is selected from diethylamino, dimethylamino and diisopropylamino or a combination of at least two thereof, particularly preferably hydrogen,

[0031] R202 is hydrogen, C1 to C4 alkyl, hydroxy or C1 to C4 alkoxy, particularly preferably hydrogen,

[0032] R203 is hydrogen or forms a -CH=CH-CH=CH- bridge with R202, particularly preferably hydrogen, R204 is hydrogen or phenyl, particularly preferably hydrogen,

[0033] R206 is hydrogen, hydroxy or C1 to C4 alkoxy, particularly preferably hydrogen, and

[0034] Anionn- Selected from C8 to C 25 Alkyl sulfonate, preferably C 13 To C 25 Alkyl sulfonate, C8 to C 25 Alkyl sulfate, preferably C 13 To C 25 Alkyl sulfate, di-C4 to C 25 Alkyl-, C5 to C7 cycloalkyl-, C3 to C8 alkenyl- or C7 to C 11 Arylalkyl sulfosuccinate, C8 to C 25 Alkyl sulfoacetate, di-C4 to C 25 Alkyl sulfosuccinate, especially (2-ethylhexyl) sulfosuccinate, C4 to C 25 Alkyl-substituted benzenesulfonates, in particular dodecylbenzenesulfonate and tetraphenylborate, in particular tetraphenylborate, are particularly preferably selected from (2-ethylhexyl)sulfosuccinate, dodecylbenzenesulfonate and tetraphenylborate.

[0035] Another subject of the present invention relates to a process for preparing benzopyrylium dyes, in particular benzopyrylium dyes according to the invention, which process comprises a multi-stage reaction sequence, in which at least the following reaction stages are carried out:

[0036] A. In the first reaction stage P1.:

[0037] P1.i. dissolving the corresponding selected 2-hydroxyarylcarbonyl derivative together with the corresponding indanone derivative or tetralone derivative in a weak acid, preferably acetic acid,

[0038] P1.ii. heating the mixture from P1.i with addition of a strong acid, wherein the mixture is preferably refluxed until complete conversion,

[0039] P1.iii. cooling and washing the mixture from P1.ii. with a nonpolar aprotic solvent,

[0040] P1.iv. separating the phase insoluble in the nonpolar aprotic solvent and placing the phase in water;

[0041] B. In the second reaction stage P2:

[0042] P2.i. Dye anion A n- An alkali metal salt and a nonpolar aprotic solvent are added to the aqueous solution from P1.iv.,

[0043] P2.ii. stirring and optionally heating the mixture from P2.i., separating off the aqueous phase and discarding it including the salts contained therein,

[0044] P2.iii. washing the mixture from P2.ii. with water, preferably to the end point, and

[0045] P2.iv. Optionally removing the solvent under vacuum and optionally drying the benzopyrylium dye of the present invention under vacuum.

[0046] If the dye precipitates after the first reaction stage P1., it is filtered off, washed with a nonpolar aprotic solvent and used as a purified product together with water in the second reaction stage P2. If the crude product is insoluble in water, the oil phase containing the crude product is washed with a nonpolar aprotic solvent in step P1.iv. and processed further in the second reaction stage P2. together with water.

[0047] The benzopyrylium dyes herein are preferably prepared by a one-pot reaction according to the following reaction formula:

[0048]

[0049] In the one-pot reaction scheme, in the first reaction stage P1., the corresponding 2-hydroxyarylcarbonyl derivative and the corresponding indanone or tetralone derivative are first dissolved in glacial acetic acid in a 1:1 equivalent ratio in step P1.i. In step P1.ii., a strong acid, preferably a strong acid with a pKa value of ≤4, particularly preferably ≤3, especially preferably ≤2, most preferably ≤1, such as sulfuric acid, is added slowly, preferably within 1 to 5 hours, and the mixture is heated under reflux until the conversion is complete. After cooling to preferably 10 to 40° C., more preferably 20 to 30° C., particularly preferably 23 to 25° C. in step P1.iii., the reaction solution is diluted with a nonpolar aprotic solvent, such as methyl tert-butyl ether (MTBE), and mixed vigorously. In step P1.iv., the phase insoluble in the solvent is separated off and dissolved in water. In the second reaction stage P2., an alkali metal salt of the dye anion and an ester solvent (e.g. butyl acetate) are added to the aqueous solution in step P2.i. to form an ester solvent / water mixture, which is stirred in step P2.ii. with gentle heating, preferably to a maximum of 50° C., more preferably to a maximum of 40° C. The phases are separated in step P2.iii. 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 vacuum, preferably 10 to 50 mbar), a high-viscosity oily product is obtained.

[0050] If, according to the above process, the crude product precipitates out in solid form after the first stage P1., it is filtered off, washed with a nonpolar aprotic solvent (eg MTBE) and used as purified product in the second stage together with water.

[0051] If, according to the above process, the crude product is not soluble in water, the oil phase containing the crude product is washed with a nonpolar aprotic solvent, such as MTBE. The product purified in this way is further processed in a second stage P2. together with water.

[0052] Another subject of the present invention relates to the use of the benzopyrylium dye of the present invention, preferably as part of a two-component photoinitiator system, in a photocurable formulation in combination with a suitable electron donor for improving the bleaching property of the photocurable material. The benzopyrylium dye of the present invention is preferably used to initiate free radical polymerization after irradiation with actinic radiation. Preferably, an electron donor selected from triarylalkylborates, trifluoroalkylborates, tertiary amines, pentacoordinated silicates and dihydropyridines is used here. Preferably, the benzopyrylium dye of the present invention is used together with an electron donor in a three-component photoinitiator system with an electron acceptor selected from iodonium salts, sulfonium salts, trichlorotriazines, electron-deficient trihalomethyl aromatic compounds and Katritzky salts or a mixture of at least two thereof. The electron-deficient trihalomethyl aromatic compound is preferably a trichloromethyl aromatic compound having a strongly electronegative substituent, such as at least one fluorine atom, as described in Examples 1-9 of WO 2015 / 091427, pages 19-22. Particular preference is given to using triarylalkylborates as electron donors and the benzopyrylium dyes of the invention as photoinitiator systems. Corresponding triarylalkylborates are known from US Pat. No. 11098066, in particular as described in Example 26 on page 47.

[0053] Very particularly preferably, these trialkylborates are selected from the following structures, in which n is selected between 1 and 2, and K + For any monovalent cation:

[0054]

[0055] Preferably, the benzopyrylium dyes of the present invention are used as part of a three-component photoinitiator system, wherein an electron acceptor is added in addition to the above-mentioned type II photoinitiator system. The electron acceptor is preferably selected from iodonium salts, sulfonium salts, trichlorotriazines, trichloroaromatic compounds described in WO2015 / 091427 or Katritzky salts.

[0056] Another subject of the present invention relates to a photopolymer composition comprising at least a) a matrix polymer, b) a writing monomer, c) a non-photopolymerizable component, d) a photoinitiator system (PIS), which comprises 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 e) a catalyst, a free radical stabilizer, a solvent, additives and other auxiliaries and / or additives.

[0057] As matrix polymer a), writing monomer b) and non-photopolymerizable component c) and PIS d), all components known to the person skilled in the art for this purpose can be used. Matrix polymer a) is known, for example, from the prior art US8921012, writing monomer b) is known, for example, from the prior art US2010086860, US8222314 and US10241402, non-photopolymerizable component c) and PIS d) are known, for example, from the prior art US10001703 and US9146456, and optional non-photopolymerizable component c) is known, for example, from the prior art US8999608. As optional component e), all catalysts, free radical stabilizers, solvents, additives and other auxiliaries and / or additives known to the person skilled in the art for this purpose can be used.

[0058] Preferred low-refractive-index matrix polymers a) are polyurethanes obtainable, for example, by reaction of a polyol component with a polyisocyanate component.

[0059] Preferably, the writing monomer b) comprises at least one monofunctional and / or polyfunctional writing monomer or a composition thereof. Further preferably, the writing monomer b) may comprise at least one monofunctional and / or polyfunctional (meth)acrylate writing monomer or consist thereof. Particularly preferably, the writing monomer may comprise at least one monofunctional and / or polyfunctional urethane (meth)acrylate or consist thereof.

[0060] The at least one non-photopolymerizable component c) may be any of the components c) that a person skilled in the art would select for the photopolymer composition of the present invention.

[0061] The at least one photoinitiator system d) can be any of the various photoinitiator systems that a person skilled in the art would select for the photopolymer composition of the invention. The photoinitiator of component d) is generally a compound that can be activated by actinic radiation and that is capable of initiating the polymerization of the writing monomers. Photoinitiators can be divided into unimolecular (type I) and bimolecular (type II) initiators. Furthermore, they can be divided, according to their chemical nature, into photoinitiators that polymerize in free radical, anionic, cationic or mixed modes.

[0062] Type I photoinitiators for free radical photopolymerization (Norrish Type I) form free radicals by unimolecular bond cleavage under irradiation. Examples of Type I photoinitiators are triazines, oximes, benzoin ethers, benzil ketals, bisimidazoles, aroylphosphine oxides, sulfonium salts and iodonium salts.

[0063] Type II photoinitiators (Norrish II type) for free radical polymerization consist of a dye as a sensitizer and a co-initiator, which undergo a bimolecular reaction when irradiated with light that is compatible with the dye. First, the dye absorbs photons and can react bimolecularly from its excited state with the compatible co-initiator. The latter releases polymerization-initiating free radicals by electron or proton transfer or direct hydrogen abstraction.

[0064] Preference is given to using type II photoinitiators. Further preferred photoinitiator systems d) are described in principle in EP 0 223 587 A and preferably consist of a mixture of one or more dyes.

[0065] It is preferably provided that the photopolymer composition further comprises a urethane as an additive to component c), wherein the urethane may in particular be substituted by at least one fluorine atom.

[0066] Likewise, the benzopyrylium dyes of the present invention may also be used in cured photopolymers having characteristics similar to those of the photopolymer compositions described above.

[0067] All statements concerning the benzopyrylium dyes of the present invention (in the form of benzopyrylium salts of formula (I)) and the associated anions An n- The selection can be made analogously to what has been stated for the benzopyrylium salts of the formula (I) according to the invention for use.

[0068] Another subject matter of the invention relates to a layer structure comprising at least the following layers:

[0069] A. Base layer A., ​​which is optionally part of another layer structure,

[0070] B. A photopolymer layer B. comprising a photopolymer composition according to the invention, and

[0071] C. Optional covering layer C., which is optionally part of another layer structure.

[0072] The photopolymer composition has the same components, component ratios and properties as the above-mentioned photopolymer composition of the present invention. The layer structure may contain other layers. Preferably, the substrate layer A. and the cover layer C. have an adhesive layer on at least one of the two surfaces so that the substrate layer A. or the cover layer C. can be joined to the polymer layer B. or another outer layer.

[0073] Another subject matter of the invention relates to a layer structure comprising at least the following layers:

[0074] A. Base layer A., ​​which is optionally part of another layer structure,

[0075] B. a cured photopolymer layer B', which is produced by curing the photopolymer composition of the invention with light, and

[0076] C. Optional covering layer C., which is optionally part of another layer structure.

[0077] The photopolymer composition has the same components, component ratios and properties as the above-mentioned photopolymer composition of the present invention. The layer structure may contain other layers. Preferably, the base layer A. and the cover layer C. have an adhesive layer on at least one of the two surfaces so that the base layer A. or the cover layer C. can be bonded to the cured polymer layer B'. or another outer layer.

[0078] Another subject matter of the present invention relates to a holographic medium comprising a benzopyrylium dye according to the invention or a benzopyrylium dye prepared by the process according to the invention, or a photopolymer composition according to the invention. In addition, a method for producing a holographic medium using a benzopyrylium dye according to the invention (for example in the form of a photopolymer composition comprising a benzopyrylium dye according to the invention as described above) is disclosed. The dye according to the invention or the photopolymer composition according to the invention can be used in particular for producing holographic media in the form of a film. In this case, a layer of a material or a material composite which is transparent to light in the visible and near-infrared spectral range (transmittance in the wavelength range of 400 to 1200 nm is greater than 85%) as a carrier (in the form of a substrate layer A.) is coated on one or both sides in the dark with a photopolymer composition B., and optionally a covering layer C. is applied to the one or more photopolymer layers B. Preferred materials or material composites for the carrier (in the form of the 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. They are more preferably based on PC, PET and CTA. The material composites can be film laminates or coextrudates. Preferred material composites are double-layer and triple-layer films constructed according to one of the schemes A. / B., A. / B. / A. or A. / B. / C. PC / PET, PET / PC / PET and PC / TPU (TPU=thermoplastic polyurethane) are particularly preferred. The materials or material composites for the carrier (in the form of the substrate layer A.) can be given a non-stick, antistatic, hydrophobic or hydrophilic treatment on one or both sides. Likewise, the material or material composite can be activated primarily by plasma pretreatment or UV irradiation. The modification is applied to the side facing the photopolymer layer B, with the aim of making the photopolymer layer B. adhere more firmly to the substrate layer A. or, conversely, be able to detach from the substrate layer A. without being destroyed. The modification of the side of the carrier (in the form of the substrate layer A.) facing away from the photopolymer layer B. serves to make the medium of the invention meet specific mechanical requirements, which are necessary, for example, for processing in a roll laminator, in particular for processing in a roll-to-roll process. The cover layer C. preferably has the same materials, properties and composition as the substrate layer A. and is preferably produced in the same way as the substrate layer A.

[0079] Furthermore, another method for producing holographic media using the benzopyrylium dyes of the invention (in particular in the form of the above-mentioned photopolymer compositions containing at least the benzopyrylium dyes) is disclosed, which also provides holographic media in the form of thin films or layer structures. In this case, a layer of a material or material composite that is transparent to light in the visible and near-infrared spectral range (transmittance greater than 85% in the wavelength range from 400 to 1200 nm) as a substrate layer A. is applied on one side by 2D printing with a photopolymer composition B. in the dark, and a cover layer C. is optionally applied to the one or more photopolymer layers B. All common inkjet technologies can be used here. Optionally, only the areas required for the function can be printed in a targeted manner with the photopolymer composition B. Preferred materials or material composites for the carrier are based on glass, silicon (in the form of high-polished wafers known in semiconductor technology), polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene, polypropylene, cellulose acetate, cellulose hydrate, nitrocellulose, cycloolefin polymers, polystyrene, polyepoxides, polysulfones, cellulose triacetate (CTA), polyamide, polymethyl methacrylate, polyvinyl chloride, polyvinyl butyral or polydicyclopentadiene or mixtures thereof. They are more preferably based on PC, PET and CTA. The material composites can be film laminates or coextrudates. Preferred material composites are double-layer and triple-layer films constructed according to one of the schemes A. / B., A. / B. / A. or A. / B. / C. PC / PET, PET / PC / PET and PC / TPU (TPU=thermoplastic polyurethane) are particularly preferred. The materials or material composites for the carrier can be given a non-stick, antistatic, hydrophobic or hydrophilic treatment on one or both sides. The modification is applied to the side facing the photopolymer layer B. in order to allow the photopolymer layer B. to be detachable from the support in the form of the substrate layer A. without being destroyed. The modification of the side of the support facing away from the photopolymer layer B. serves to enable the medium according to the invention to meet specific mechanical requirements, which are necessary, for example, for processing in a roll laminator, in particular in a roll-to-roll process.

[0080] Further preferred are material composites of the type described above which contain a photocured photopolymer layer B', thereby forming double-layer and triple-layer films according to the schemes A. / B'., A. / B'. / A. or A. / B'. / C.

[0081] In addition, another method for producing a holographic medium using the benzopyrylium dye of the present invention (especially in the form of a photopolymer composition containing at least a benzopyrylium dye as described above) is disclosed, which also provides a holographic medium in the form of a glass (D.) or acrylic (E.) composite. In the dark, the photopolymer composition here is directly embedded between two glass or acrylic layers. This is preferably done by a method selected from the following group: injecting the photopolymer composition into the cavity of two glass or acrylic surfaces, applying to the glass or acrylic surface by spraying, scraping or dipping, nozzle coating, roller coating or spin coating, or laminating a free photopolymer film and covering it with a second glass or acrylic surface. Preferred are D. / B. / D., D. / B. / E., E. / B. / D., E. / B. / E., D. / B. / A. or E. / B. / A. layer structures, wherein D. represents a glass layer and E. represents an acrylic layer. Layers D. and E. are preferably given a non-stick, hydrophobic or hydrophilic treatment. The modification is applied to the side facing the photopolymer layer B., with the aim of making the photopolymer layer B. adhere more firmly to the surface facing D. or E., or, on the contrary, detachable from the surface without damage. Further preferred are glass or acrylic composites according to the above type, which contain a photocured photopolymer layer B'., thereby forming a composite according to the scheme D. / B'. / D., D. / B'. / E., E. / B'. / D., E. / B'. / E., D. / B'. / A. or E. / B'. / A.

[0082] Holographic information in the form of a hologram can be exposed into such a holographic medium.

[0083] The holographic medium of the present invention can be processed into holograms by corresponding exposure procedures for optical applications in the near infrared and the entire visible and near ultraviolet range (350-1500nm).Holograms include all holograms that can be recorded by methods known to those skilled in the art.

[0084] Another subject of the invention relates to a hologram obtainable from the holographic medium according to the invention. As described above, this hologram is obtained by correspondingly exposing the holographic medium.

[0085] A preferred embodiment of the hologram is selected from the group consisting of off-axis holograms, full-aperture transmission holograms, white light transmission holograms ("rainbow holograms"), Denisyuk holograms, off-axis reflection holograms, side-lit holograms and holographic stereograms. Reflection holograms, Denisyuk holograms, transmission holograms or a combination of at least two of these are preferred. Preferably, a combination of these hologram types or a plurality of holograms of the same type are combined independently of one another in the same volume of the holographic medium, also called multiplexing.

[0086] Possible optical functions of holograms which can be prepared with a photopolymer composition comprising at least one benzopyrylium dye according to the invention correspond to the optical functions of optical elements, such as lenses, reflectors, deflection mirrors, filters, diffuser lenses, diffractive elements, diffusers, light conductors (waveguides), light deflectors, projection lenses and / or masks. Combinations of these optical functions can also be combined in the hologram independently of one another. These optical elements generally exhibit frequency selectivity, which depends on how the hologram is exposed and what size the hologram has.

[0087] Furthermore, holographic images or displays in the form of holograms can also be produced by means of holographic media, for example for personal portraits, biometric features in security documents or, in general, for images or image structures used in advertising, security labels, brand protection, brand marketing, labels, design elements, decorations, illustrations, collection cards, images, etc., as well as images that can represent digital data, in particular including in combination with the above-mentioned products. Holographic images can have the impression of a three-dimensional image, but they can also represent image sequences, short films or a number of different objects, depending on the angle at which they are illuminated, with what (also moving) light source, etc.

[0088] A further subject matter of the present invention relates to an optical display comprising the inventive holographic medium or the inventive hologram.

[0089] A further subject matter of the present invention is the use of the photopolymer compositions according to the invention for producing holographic media or holograms.

[0090] The above-mentioned functionalities of holograms which can be produced with the benzopyrylium dyes of the invention or the photopolymer compositions of the invention can be used, for example (but not only) for eye tracking, sensing, as well as lidar and augmented reality, head-mounted displays and virtual reality applications in the near infrared range.

[0091] A further subject matter of the present invention relates to the use of the holographic medium according to the invention for producing chip cards, identification documents, 3D images, product protection labels, tags, banknotes or holographic optical elements, in particular holographic optical elements for optical displays, or in a medium for realizing a method for realizing an application selected from eye tracking, sensing, lidar, augmented reality, head-mounted displays, head-up displays and virtual reality applications, in particular virtual reality applications in the near infrared range and a combination of at least two thereof.

[0092] The holographic medium can be used to record on-axis, off-axis, full-aperture transmission, white light transmission, Denisyuk, off-axis reflection or side-light holograms and holographic stereograms, and is particularly suitable for manufacturing optical elements, images or image displays.

[0093] The hologram is preferably obtained from the holographic medium according to the invention by exposure. Example:

[0094] The following examples are provided to illustrate the present invention, but the present invention is not limited thereto.

[0095] Measurement method:

[0096] OH value: The indicated OH values ​​were determined in accordance with DIN 53240-2-2007-11.

[0097] NCO value: The indicated NCO values ​​(isocyanate content) were determined in accordance with DIN EN ISO 11909-2007-05.

[0098] The holographic properties DE and Δn of the holographic medium are measured using double-beam interferometry in a reflection setup:

[0099] like Figure 1 As shown, a spatial filter (SF) and a collimating lens (CL) are used to convert the beam of a blue DPSS laser emitting at a wavelength λ of 457 nm in vacuum into a parallel uniform beam. The final cross-sections of the signal and reference beams are fixed by a variable aperture (I). The diameter of the variable aperture opening is 0.4 cm. A polarization-dependent beam splitter (PBS) splits the laser beam into two coherent, equally polarized beams. The power of the reference beam is set to 0.5 mW and the power of the signal beam is set to 0.65 mW by a λ / 2 plate. The power is measured using a semiconductor detector (D) with the sample removed. The incident angle (α0) of the reference beam is -22.0° and the incident angle (β0) of the signal beam is 42.0°. The angle is measured relative to the beam direction starting from the sample normal direction. Therefore, according to Figure 1 , α0 has a negative sign and β0 has a positive sign. At the location of the sample (holographic medium), the interference field of the two overlapping beams produces a grating of light and dark stripes (reflection hologram) perpendicular to the angular bisector of the two beams incident on the sample. The strip spacing Λ (also called grating period) in the holographic medium is about 225nm (the refractive index of the holographic medium is assumed to be about 1.504).

[0100] Figure 1 The holographic experimental setup for measuring the diffraction efficiency (DE) of holographic media is shown. Figure 1 The geometric parameters of the holographic medium tester (HMT) at λ = 457nm (DPSS laser) are shown (M = mirror, S = shutter, SF = spatial filter, CL = collimating lens, λ / 2 = λ / 2 plate, PBS = polarization sensitive beam splitter, D = detector, I = variable aperture, α0 = -22°, β0 = 42° is the incident angle of the coherent light beam measured outside the sample (holographic medium), RD = reference direction of the turntable).

[0101] Holograms are written to holographic media in the following manner:

[0102] Both shutters (S) are open for exposure time t.

[0103] • Subsequently, with the shutter (S) closed, the holographic medium was allowed to diffuse the unpolymerized writing monomers for a period of 5 minutes.

[0104] The written hologram is now read out in the following manner. The shutter of the signal beam remains closed. The shutter of the reference beam is opened. The variable aperture of the reference beam is closed to a diameter of <1 mm. This ensures that the beam is always completely within the previously written hologram at all rotation angles (Ω) of the holographic medium. Now, under computer control, the turntable scans Ω in angular steps of 0.05°. 最小 To Ω 最大 Ω is measured from the sample normal with respect to the reference direction of the rotating disk. The reference direction of the rotating disk is obtained when the angles of incidence of the reference beam and the signal beam during writing the hologram have the same absolute value, i.e. α0 = -32° and β0 = 32°. In this case, Ω 记录 =0°. For α0 = -22° and β0 = 42°, therefore Ω 记录 is 10°. In general, for the interference field during writing ("recording") of a hologram, it applies that:

[0105] α0=θ0+Ω 记录 (2).

[0106] θ0 is the half angle in the laboratory system outside the holographic medium and what applies during hologram writing is:

[0107]

[0108] In this case, θ0 = -32°. At each rotation angle Ω passed, the power of the zero-order transmitted beam is measured by the corresponding detector D, and the power of the first-order diffracted beam is measured by the detector D. At each angle Ω passed, the diffraction efficiency η is calculated as the following quotient:

[0109]

[0110] P D is the power of the diffracted beam in the detector, P T is the power of the transmitted beam in the detector.

[0111] The Bragg curve is measured by the above method and stored in the computer, which describes the relationship between the diffraction efficiency η of the written hologram and the rotation angle Ω. In addition, the relationship between the intensity of the zero-order transmission and the rotation angle Ω is also recorded and stored in the computer.

[0112] The maximum diffraction efficiency of the hologram (DE = η 最大 ), that is, its peak value, is in Ω重建 To this end, it is possible to change the position of the detector of the diffracted light beam in order to determine this maximum.

[0113] The refractive index contrast Δn and the thickness d of the photopolymer layer (i.e., the sample or holographic medium) are now determined from the measured Bragg curve and the angular variation of the transmitted intensity using coupled wave theory (see: H. Kogelnik, The Bell System Technical Journal, Vol. 48, No. 9, November 1969, pp. 2909-2947). It should be noted that due to the thickness contraction caused by photopolymerization, the stripe spacing Λ' and the stripe direction (inclination) of the hologram may deviate from the stripe spacing Λ and its direction of the interference pattern. Therefore, the angle α0' at which the maximum diffraction efficiency is achieved and the corresponding angle Ω of the rotating disk are 重建 Deviation from α0 or corresponding Ω 记录 This will change the Prague conditions. This change in the evaluation method will be taken into account. The evaluation method is as follows:

[0114] All geometrical parameters related to the written hologram and not to the interference pattern are expressed as parameters of the stroke.

[0115] For the Bragg curve η(Ω) of the reflection hologram, according to Kogelnik it applies:

[0116]

[0117] in:

[0118]

[0119] When reading out the hologram ("reconstructing"), analogously to the above applies:

[0120]

[0121] Under the Bragg condition, the "de-phasing" is DP = 0. Accordingly, it can be obtained that:

[0122] α′0=θ0+Ω 重建 (15)

[0123] sin(α′0)=n·sin(α′) (16)

[0124] The still unknown angle β' can be determined by comparing the Bragg conditions of the interference field when writing the hologram with the Bragg conditions when reading the hologram, assuming that only thickness contraction occurs. Then it follows that:

[0125]

[0126] ν is the grating strength, ξ is the detuning parameter, ψ' is the orientation (tilt) of the written refractive index grating. α' and β' correspond to the angles α0 and β0 of the interference field when the hologram is written, but measured in the holographic medium and valid for the holographic grating (after thickness shrinkage). n is the average refractive index of the photopolymer, set to 1.504. λ is the wavelength of the laser in vacuum.

[0127] When ξ=0, the maximum diffraction efficiency (DE=η 最大 )for:

[0128]

[0129] like Figure 2 Measured data of diffraction efficiency, theoretical Bragg curve and transmitted intensity relative to the central rotation angle are shown in Figure 2. (also called angular detuning (x-axis)). Figure 2 The measured transmitted power P is shown T (right y-axis) (as a solid line) (here Example 5) as a function of the angular detuning ΔΩ, the measured diffraction efficiency η (left y-axis) (as a solid circle) as a function of the angular detuning ΔΩ (as long as the finite size of the detector allows), and the fit to the Kogelnik theory (as a dotted line) (left y-axis).

[0130] Since DE is known, the shape of the theoretical Bragg curve according to Kogelnik is only determined by the thickness d' of the photopolymer layer. For a given thickness d', DE is subsequently corrected by Δn so that the measured and theoretical values ​​of DE always agree. d" is now adjusted until the angular position of the first secondary minimum of the theoretical Bragg curve coincides with the angular position of the first secondary maximum of the transmitted intensity, and furthermore the full width at half maximum (FWHM) of the theoretical Bragg curve and the transmitted intensity agree.

[0131] Since the orientation of the reflected hologram is also rotated when reconstructed by the Ω scan, but the detector of the diffracted light can only capture a limited angular range, the Bragg curve of a wide hologram (small d') cannot be fully captured in the Ω scan, but only covers the central area if the detector is positioned appropriately. Therefore, the transmission intensity shape complementary to the Bragg curve is also used to adjust the layer thickness d'.

[0132] Figure 2 The Bragg curve η (dashed line) according to coupled wave theory, the measured diffraction efficiency (solid circles) and the transmitted power (black solid line) are shown as a function of the angular detuning ΔΩ.

[0133] In order to formulate, the method may be repeated several times on different holographic media with different exposure times t to determine at which average energy dose of the incident laser beam DE reaches the saturation value when writing the hologram. The average energy dose E is given by the power (reference beam P) allocated to the two partial beams at angles α0 and β0 as follows: r =1.31mW, signal beam P s =1.69mW), exposure time t and variable aperture diameter (0.4cm) yield:

[0134]

[0135] The powers of the partial beams are adjusted in such a way that the same power density is achieved in the holographic medium at the angles α0 and β0 used.

[0136] substance:

[0137] Solvents, reagents and all bromoaryles used were purchased from chemical suppliers. Bromoaryles were optionally freshly distilled. Anhydrous solvents contained <50 ppm of water.

[0138] Polyol 1 was prepared in the same manner as Polyol 1 described in WO2015091427, and its OH value was 56.8.

[0139] N 3900 is a product of Covestro AG, Leverkusen, Germany. It is a polyisocyanate based on hexane diisocyanate with an iminooxadiazinedione content of at least 30%. NCO content: 23.5%.

[0140] UL-28 urethanation catalyst, a commercial product of Momentive Performance Chemicals, Wilton, Connecticut, USA. Urethane acrylate 1 (phosphorothioate tris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) triacrylate, [CAS No. 1072454-85-3]), prepared according to the method in WO2015091427. Urethane acrylate 2 Prop-2-enoic acid (2-({[3-(methylsulfanyl)phenyl]carbamoyl}oxy)-ethyl ester, [CAS No. 1207339-61-4]), prepared according to the description in WO2015091427.

[0141] 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 No. 1799437-41-4]), prepared according to the method in WO2015091427.

[0142] Co-initiator 1 (N-benzyl-N,N-dimethylhexadecyl ammonium tris-(3-chloro-4-methylphenyl)hexyl borate, [CAS No. 1702465-82-4]) was prepared from 1-bromo-3-chlorobenzene, diisopropylhexyl borate and N-benzyl-N,N-dimethylhexadecyl ammonium chloride as described in WO2018087064.

[0143] BYK-310 silicone-containing surface additive, BYK-

[0144] Products of Chemie GmbH.

[0145] Dye 1 Benzopyrylium dye 5,6-dihydro-3,10-dimethoxy-7-phenylbenzo[C]xanthenium perchlorate [CAS No. 126634-30-8], sourced from Synthon Chemicals GmbH & Co. KG, Bitterfeld-Wolfen, Germany.

[0146] Dye 2(1,3,3-trimethyl-2-[2-(1-methyl-2-phenyl-1H-indole-3-

[0147] [(2-ethylhexyl)vinyl]-3H-indolium bis(2-ethylhexyl)sulfosuccinate [CAS No. 1374689-54-9]), prepared according to the method in WO2012062655.

[0148] Dye 3 2-[2-[4-[(2-chloroethyl)methylamino]phenyl]vinyl]-1,3,3-trimethyl-3H-indolium bis(2-ethylhexyl)sulfosuccinate [CAS No. 153952-28-4], prepared according to the method in WO2012062655.

[0149] Synthesis Procedure:

[0150] Preparation Procedure A (for 200 , R 204 , R 205 , R 207 and R 208 =H and any R other than NR2 201 Benzopyranium salt of

[0151]

[0152] The corresponding 2-hydroxyaromatic aldehyde derivative (1.0 equivalent) was dissolved in glacial acetic acid (0.4 M) together with the corresponding tetralone derivative (1.0 equivalent). Sulfuric acid (2.0 equivalent) was slowly added and the mixture was heated under 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, the reaction product was washed with MTBE (2 times), and vacuum dried. The reaction product was then dissolved in a butyl acetate / water mixture (1:1) at 50°C together 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 water, 6 times). After vacuum removal of the solvent and vacuum drying of the residue, a highly viscous oily product was obtained.

[0153] Preparation Procedure B (for R 200 , R 203 , R 205 , R 207 and R 208 =H and R 204 =Ph benzopyrylium bis(2-ethylhexyl)sulfosuccinate):

[0154]

[0155] The corresponding 2-hydroxybenzophenone derivative (1.0 equivalent) is dissolved in glacial acetic acid (0.4 M) together with the corresponding tetralone derivative (1.0 equivalent). Sulfuric acid (2.0 equivalent) is slowly added and the mixture is heated under reflux for at least 8 hours. After cooling to room temperature, the reaction solution is added to methyl tert-butyl ether (MTBE) and the product precipitates out as an insoluble oil. The ether phase is separated and the oil phase is washed several times with MTBE. The product is dissolved in a butyl acetate / water mixture (1:1) at 50°C together with sodium bis(2-ethylhexyl) sulfosuccinate and stirred vigorously overnight. The phases are separated and the organic phase is washed with water (deionized water, 6 times). After vacuum removal of the solvent and vacuum drying of the residue, a highly viscous oily product is obtained.

[0156] Preparation Procedure C (for 200 , R 202 , R 203 , R 204 , R 205 , R 207 and R 208 =H and R 201 = NEt2 benzopyranium bis (2-ethylhexyl) sulfosuccinate):

[0157]

[0158] 4-Diethylamino salicylaldehyde (1.0 equivalent) was dissolved in glacial acetic acid (0.4 M) together with the corresponding tetralone derivative (1.0 equivalent). Sulfuric acid (2.0 equivalent) 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) and the product was precipitated as an insoluble oil. The ether phase was separated and the product was placed in water (deionized water). The aqueous phase was washed with MTBE (3 times) and finally a solution of ethyl butyrate of sodium bis(2-ethylhexyl) sulfosuccinate (0.9 equivalent) was vigorously stirred overnight as a two-phase mixture. The phases were separated and the organic phase was washed with water (deionized water, 6 times). The product was obtained after vacuum removal of the solvent and vacuum drying of the residue.

[0159] Preparation Procedure D (for photopolymer films / holographic media):

[0160] 5.85 g of the above polyol component 1 was melted and mixed with 2.16 g of urethane acrylate 1, 6.48 g of urethane acrylate 2, 5.4 g of 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 UL-28 was mixed with 8.4 g of ethyl acetate to obtain a clear solution. Then 1.08 g of N 3900 and mixed again. The solution was placed on a TAC film with a thickness of 60 μm on a roll-to-roll coating device in the dark and applied with a doctor blade to a wet layer thickness range of 12-14 μm. The coated film was dried at a drying temperature of 120°C and a drying time of 4 minutes and then protected with a polyethylene film with a thickness of 40 μm. Subsequently, the film was light-proof packaged.

[0161] Example

[0162] Example 1: Preparation of 12,13-dihydro-10-methoxydibenzo[a,h]xanthene bis(2-ethylhexyl)sulfosuccinate Amber ester and preparation of 12,13-dihydro-10-methoxydibenzo[a,h]xanthene bis(2-ethylhexyl)sulfosuccinate Holographic media:

[0163] According to general preparation procedure A, 2-hydroxynaphthaldehyde was reacted with 6-methoxy-1-tetralone and ion exchanged using sodium bis(2-ethylhexyl)sulfosuccinate. A high-viscosity red oil was obtained (1.81 g, 72% of theory in two stages). According to preparation procedure D, a holographic medium containing this benzopyranium dye was prepared.

[0164] 1H NMR (600MHz, CDCl3): δ10.39(s,1H),9.18(d,J=8.4Hz,1H),8.44(d,J=9.2Hz,1H),8.36(d,J=8.8Hz,1 H),8.06(ddd,J=11.0,7.5,2.0Hz,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).

[0165] Absorption maximum (in acetone): 479–490 nm.

[0166] Example 2: Preparation of 5,6-dihydro-3,9,10-trimethoxybenzo[C]xanthene bis(2-ethylhexyl)sulfosuccinate Amber ester and preparation of 5,6-dihydro-3,9,10-trimethoxybenzo[C]xanthene bis(2-ethylhexyl)sulfosuccinate Holographic media:

[0167] According to the general preparation procedure A, 2-hydroxy-4,5-dimethoxybenzaldehyde was reacted with 6-methoxy-1-tetralone and ion exchanged using sodium bis(2-ethylhexyl)sulfosuccinate. A high-viscosity orange oil was obtained (2.3 g, 90% of theory in two stages). According to the preparation procedure D, a holographic medium containing the benzopyranium dye was prepared.

[0168] 1 H NMR (600MHz, CDCl3): δ9.17(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).

[0169] Absorption maximum (in acetone): 480–492 nm.

[0170] Example 3: Preparation of 10-(diethylamino)-5,6-dihydro-3-methoxybenzo[C]xanthene bis(2-ethylhexyl) 10-(diethylamino)-5,6-dihydro-3-methoxybenzo[C]xanthene bis(2-ethyl)sulfosuccinate Holographic media of hexyl) sulfosuccinate:

[0171] 6-Methoxy-1-tetralone was reacted according to general preparation procedure C. A high-viscosity purple oil was obtained (1.2 g, 76% of theory in two stages). According to preparation procedure D, a holographic medium containing the benzopyrylium dye was prepared.

[0172] 1 H NMR (600MHz, CDCl3): δ8.98 (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(d d,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).

[0173] Absorption maximum (in acetone): 543–572 nm.

[0174] Example 4: Preparation of 10-(diethylamino)-5,6-dihydrobenzo[C]xanthene bis-(2-ethylhexyl)sulfosuccinimide Amber ester and preparation of 10-(diethylamino)-5,6-dihydrobenzo[C]xanthene bis-(2-ethylhexyl)sulfosuccinate Holographic media:

[0175] 1-Tetralone was reacted according to general preparation procedure C. A high-viscosity purple oil was obtained (1.4 g, 64% of theory in two stages). According to preparation procedure D, a holographic medium containing the benzopyrylium dye was prepared.

[0176] 1H NMR (600MHz, CDCl3): δ8.93 (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(td,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).

[0177] Absorption maximum (in acetone): 527–554 nm.

[0178] Example 5: Preparation of 5,6-dihydro-3,10-dimethoxy-7-phenylbenzo[C]xanthene bis(2-ethylhexyl) Sulfosuccinates and preparation thereof containing 5,6-dihydro-3,10-dimethoxy-7-phenylbenzo[C]xantheneium bis(2-ethylhexyl) Holographic media of sulfosuccinates:

[0179] According to the 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 was obtained (1.8 g, 76% of theory in two stages). According to the preparation procedure D, a holographic medium containing the benzopyranium dye was prepared.

[0180] 1 H NMR (600MHz, CDCl3): δ8.74(d,J=8.9Hz,1H),8.00(d,J=2.4Hz,1H),7.65–7.61(m,3H ),7.42(d,J=9.2Hz,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).

[0181] Absorption maximum (in acetone): 471–481 nm.

[0182] Example 6: Preparation of 5,6-dihydro-3,10-dimethoxybenzo[C]xanthene bis(2-ethylhexyl)sulfosuccinate Acid esters and preparation of 5,6-dihydro-3,10-dimethoxybenzo[C]xanthene bis(2-ethylhexyl)sulfosuccinate Information medium:

[0183] According to general preparation procedure A, 4-methoxysalicylaldehyde was reacted with 6-methoxy-1-tetralone and ion exchanged using sodium bis-(2-ethylhexyl)sulfosuccinate. A red solid was obtained (2.0 g, 74% of theory in two stages). According to preparation procedure D, a holographic medium containing the benzopyranium dye was prepared.

[0184] 1 H NMR (600MHz, CDCl3): δ9.21(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=2.4Hz,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).

[0185] Absorption maximum (in acetone): 466–479 nm.

[0186] Example 7: Preparation of 5,6-dihydro-3-methoxy-9-methyl-7-phenylbenzo[C]xanthene bis(2-ethylhexyl) 5,6-dihydro-3-methoxy-9-methyl-7-phenylbenzo[C]xanthene bis(2-ethyl)sulfosuccinate Holographic media of hexyl) sulfosuccinate:

[0187] According to the general preparation procedure B, 2-hydroxy-5-methylbenzophenone was reacted with 6-methoxy-1-tetralone for 12 hours. A brown solid was obtained (0.98 g, 35% of theory in two stages). According to the preparation procedure D, a holographic medium containing the benzopyrylium dye was prepared.

[0188] 1H NMR (600MHz, CDCl3): δ8.60(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,3H),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).

[0189] Absorption maximum (in acetone): 455–464 nm.

[0190] Example 8: Preparation of 5,6-dihydro-3-methoxy-10-methylbenzo[C]xanthene bis(2-ethylhexyl)sulfonyl Succinate esters and preparation of 5,6-dihydro-3-methoxy-10-methylbenzo[C]xanthene bis(2-ethylhexyl)sulfosuccinate Holographic media of acid esters:

[0191] According to the general preparation procedure A, 2-hydroxy-4-methylbenzaldehyde was reacted with 6-methoxy-1-tetralone and ion exchanged using sodium bis(2-ethylhexyl)sulfosuccinate. A high-viscosity brown oil was obtained (1.7 g, 66% of theory in two stages). According to the preparation procedure D, a holographic medium containing this benzopyranium dye was prepared.

[0192] 1 H NMR (600MHz, CDCl3): δ9.56 (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).

[0193] Absorption maximum (in acetone): 458–463 nm.

[0194] Example 9: Preparation of 12,13-dihydrodibenzo[a,h]xanthenium bis(2-ethylhexyl)sulfosuccinate and Preparation of holographic medium containing 12,13-dihydrodibenzo[a,h]xanthene bis(2-ethylhexyl)sulfosuccinate:

[0195] According to the general preparation procedure A, 2-hydroxynaphthaldehyde was reacted with 1-tetralone and ion exchanged with sodium bis(2-ethylhexyl)sulfosuccinate. An orange solid was obtained (0.84 g, 49% of the theoretical yield in two stages). According to the preparation procedure D, a holographic medium containing the benzopyranium dye was prepared.

[0196] 1 H NMR (600MHz, CDCl3): δ10.71(s,1H),9.28(d,J=8.3Hz,1H),8.54(d,J=9.2Hz,1H),8.37(dd,J=7.9,1.2 Hz,1H),8.12–8.03(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).

[0197] Absorption maximum (in acetone): 460–462 nm.

[0198] Example 10: Preparation of 5,6-dihydro-3-methoxy-7-phenylbenzo[C]xanthene bis(2-ethylhexyl)sulfonyl Succinate ester and preparation thereof containing 5,6-dihydro-3-methoxy-7-phenylbenzo[C]xantheneium bis(2-ethylhexyl)sulfosuccinate Ester holographic medium:

[0199] According to the general preparation procedure B, 2-hydroxybenzophenone was reacted with 6-methoxy-1-tetralone for 8 hours. A high-viscosity dark orange oil was obtained (0.84 g, 27% of theory in two stages). According to the preparation procedure D, a holographic medium containing the benzopyranium dye was prepared.

[0200] 1H NMR (600MHz, CDCl3): δ8.65(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),3.1 8–3.06(m,5H),2.98–2.92(m,1H),1.54–1.47(m,2H),1.36(s,16H),0.91–0.80(m,12H).

[0201] Absorption maximum (in acetone): 455–463 nm.

[0202] Example 11: Preparation of 5,6-dihydro-3-methoxy-9-methylbenzo[C]xanthene bis(2-ethylhexyl)sulfonyl Succinate ester and preparation thereof containing 5,6-dihydro-3-methoxy-9-methylbenzo[C]xantheneium bis(2-ethylhexyl)sulfosuccinate Ester holographic media:

[0203] According to the general preparation procedure A, 2-hydroxy-5-methylbenzaldehyde was reacted with 6-methoxy-1-tetralone and ion exchanged using sodium bis(2-ethylhexyl)sulfosuccinate. A brown solid was obtained (2.2 g, 86% of theory in two stages). According to the preparation procedure D, a holographic medium containing the benzopyranium dye was prepared.

[0204] 1 H NMR (600MHz, CDCl3): δ9.51(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).

[0205] Absorption maximum (in acetone): 455–462 nm.

[0206] Example 12: Preparation of 5,6-dihydro-3,10-dimethoxybenzo[C]xanthene dodecylbenzenesulfonate and Preparation of holographic medium containing 5,6-dihydro-3,10-dimethoxybenzo[C]xantheneium dodecylbenzenesulfonate:

[0207] According to the general preparation procedure A, 4-methoxy salicylaldehyde was reacted with 6-methoxy-1-tetralone and ion exchanged using sodium dodecylbenzenesulfonate. A high-viscosity reddish-brown oil was obtained (0.41 g, 33% of theory in two stages). According to the preparation procedure D, a holographic medium containing the benzopyranium dye was prepared.

[0208] 1 H NMR (600MHz, CDCl3): δ9.62(s,1H),8.48(d,J=8.9Hz,1H),8.38(d,J=9.0Hz,1H ),7.86(d,J=7.7Hz,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).

[0209] Absorption maximum (in acetone): 472–481 nm.

[0210] Example 13: Preparation of 5,6-dihydro-3,10-dimethoxybenzo[C]xanthene tetraphenylborate and preparation of Holographic media of 5,6-dihydro-3,10-dimethoxybenzo[C]xantheneium tetraphenylborate:

[0211] According to the general preparation procedure A, 4-methoxy salicylaldehyde was reacted with 6-methoxy-1-tetralone and ion exchanged using sodium tetraphenylborate. An orange solid was obtained (0.41 g, 33% of theory in two stages). According to the preparation procedure D, a holographic medium containing the benzopyrylium dye was prepared.

[0212] 1 H NMR (600MHz, CDCl3): δ8.10(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).

[0213] Absorption maximum (in acetone): 471–482 nm.

[0214] Non-Inventive Example 1 (NEB-1): Preparation of 5,6-dihydro-3,10-dimethoxy-7-phenylbenzo[c]xanthene Holographic media of onium perchlorates:

[0215] According to preparation procedure D, a holographic medium containing Dye 1 described above was prepared.

[0216] Non-inventive Example 2 (NEB-2): Preparation of 1,3,3-trimethyl-2-[2-(1-methyl-2-phenyl-1H-indole Holographic media of [(2-(2-indol-3-yl)vinyl]-3H-indolium bis(2-ethylhexyl)sulfosuccinate]

[0217] According to preparation procedure D, a holographic medium containing dye 2 described above was prepared.

[0218] Non-inventive Example 3 (NEB-3): Preparation of a 2-[2-[4-[(2-chloroethyl)methylamino]phenyl]vinyl]- Holographic media of 1,3,3-trimethyl-3H-indolium bis(2-ethylhexyl)sulfosuccinate:

[0219] According to preparation procedure D, a holographic medium containing dye 3 described above was prepared.

[0220] Evaluation of dyes according to the invention and dyes not according to the invention:

[0221] The requirements for the photopolymer films produced here are, on the one hand, the highest possible transmittance over the entire visible spectral range from 400 nm to 800 nm. The higher the transmittance, the better the bleaching properties. On the other hand, the requirements for the photopolymer films produced here are also optical and chemical homogeneity, i.e. no turbidity, etc. can occur. If turbidity or optical inhomogeneities in the photopolymer films cannot be detected by optical inspection of these films, then these are dyes that can potentially be used for holographic media.

[0222] In order to be able to evaluate and compare the bleaching properties of the photopolymer compositions, the holographic media were tested in exactly the same way: for each example, the sample was bleached in a fully covered form under light irradiation from a metal halide lamp for 180 seconds and in a next step the transmission spectrum was recorded from 400 nm to 800 nm. The bleaching properties of the photopolymer films containing the different benzopyrylium dyes were calculated using the following formula (1) and the experimentally recorded transmission spectrum data:

[0223]

[0224] The following bleachability values ​​and optical evaluations were determined for the inventive and non-inventive examples:

[0225] Table 1 Bleachability values ​​calculated from experimentally measured transmission curves of UV-bleached photopolymer films and observations on whether crystals are formed in the photopolymer films.

[0226]

[0227]

[0228] The results obtained demonstrate that the desired bleachability and optical clarity / uniformity properties are achieved for photopolymers containing benzopyrylium dyes of the present invention. The bleachability values ​​for the novel inventive benzopyrylium dyes (Examples 1 to 14) are all lower than the two cyanine / semi-cyanine dyes of non-inventive Examples NEB-2 and NEB-3. Furthermore, no haze or optical inhomogeneity was observed in any of the inventive Examples, but was observed in Example NEB-1, which, although containing a benzopyrylium cation, was combined with a perchlorate anion and is therefore non-inventive.

[0229] Non-inventive examples NEB1, NEB2 and NEB3 are deficient in at least one desired property and are therefore not suitable for providing the desired properties.

[0230] Furthermore, the holographic performance Δn of some films was exemplarily tested by means of the above-described measurement of photopolymer films by two-beam interferometry in a reflection setup. The measurement results are summarized in Table 2 below.

[0231] Table 2 shows the results of holographic performance measurements by double-beam interference in a reflection device based on the above experimental configuration and calculations for several embodiments.

[0232]

[0233]

[0234] According to Δn in Table 2 最大 From the results of the measurements, it is clear that the novel benzopyrylium dyes can be used very well in combination with trialkylarylborates in two-component photoinitiator systems, photopolymers and holographic media. The holographic performance is at least as good as that achieved by known cyanine dyes, such as the Δn of Examples 2, 5, 7 and 10 compared to NEB-2. 最大 Comparison of the assays is shown.

Claims

1. Benzopyrylium dye of formula (I) in 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, (hetero)aryl, hydroxy, alkoxy or dialkylamino, A is -CH2- or a -CH2-CH2- bridge, and Anion n- The molecular weight of the compound is ≥200 g / mol and does not contain halogen atoms, and n is 1 to 3.

2. The benzopyrylium dye according to claim 1, wherein R 200 , R 205 , R 207 and R 208 is hydrogen, A is a -CH2-CH2- bridge, and R 204 is a group selected from hydrogen, C1 to C4 alkyl or an optionally substituted (hetero)aryl group.

3. The benzopyrylium dye according to claim 1 or 2, wherein R 200 , R 205 , R 207 and R 208 is a hydrogen atom, A is a -CH2-CH2- bridge, R 201 is selected from hydrogen, C1 to C4 alkyl, hydroxyl, C1 to C4 alkoxy or dialkylamino, wherein the dialkylamino is selected from diethylamino, dimethylamino, diisopropylamino, a six-membered saturated ring connected through the N of the amino group, which ring may additionally contain N or O and may be substituted by nonionic arbitrary groups, or a combination of at least two thereof, R 202 is hydrogen, C1 to C4 alkyl, hydroxy or C1 to C4 alkoxy, R 203 is hydrogen or with R 202 Together they form a -CH=CH-CH=CH- bridge, R 204 is hydrogen, C1 to C4 alkyl or optionally substituted (hetero)aryl, and R 206 is hydrogen, hydroxy or C1 to C4 alkoxy.

4. The benzopyrylium dye according to any one of the preceding claims, characterized in that Anion n- Selected from C8 to C 25 Alkyl sulfonate, preferably C 13 To C 25 Alkyl sulfonate, C9 to C 25 Alkanoate, C9 to C 25 Olenate, C8 to C 25 Alkyl sulfate, preferably C 13 To C 25 Alkyl sulfate, C8 to C 25 Alkenyl sulfate, preferably C 13 To C 25 Alkenyl sulfate, based on at least 5 equivalents of ethylene oxide or 5 equivalents of propylene oxide, polyether sulfate, di-C4 to C 25 Alkyl-, C5 to C7 cycloalkyl-, C3 to C8 alkenyl- or C7 to C 11 Arylalkyl sulfosuccinate, C8 to C 25 Alkyl sulfoacetate, at least one selected from C4 to C 25 Alkyl and / or C1 to C 12 Benzenesulfonate substituted with an alkoxycarbonyl group, optionally with nitro, cyano, hydroxyl, C1 to C 25 Alkyl, C1 to C 12 Alkoxy, amino, C1 to C 12 Alkoxycarbonyl-substituted naphthalenesulfonate or biphenylsulfonate, optionally substituted with nitro, cyano, hydroxyl, C1 to C 25 Alkyl, C1 to C 12 Alkoxy, C1 to C 12 Alkoxycarbonyl-substituted benzene disulfonate, naphthalene disulfonate or biphenyl disulfonate, dinitro, C6 to C 25 Alkyl, C4 to C 12 Benzoate substituted with an alkoxycarbonyl, benzoyl or methylbenzoyl group, or a mixture of at least two thereof.

5. The benzopyrylium dye according to the preceding claim, characterized in that Anion n- Selected from C8 to C 25 Alkyl sulfonate, preferably C 13 To C 25 Alkyl sulfonate, C8 to C 25 Alkyl sulfate, preferably C 13 To C 25 Alkyl sulfate, di-C4 to C 25 Alkyl-, C5 to C7 cycloalkyl-, C3 to C8 alkenyl- or C7 to C 11 Arylalkyl sulfosuccinate, C8 to C 25 Alkyl sulfoacetate, replaced by at least one selected from C4 to C 25 Alkyl and / or C1 to C 12 The alkoxycarbonyl group is substituted with benzenesulfonate and tetraphenylborate, or a combination of at least two thereof.

6. A process for preparing a benzopyrylium dye, in particular a benzopyrylium dye according to any one of the preceding claims, comprising a multi-stage reaction sequence, wherein A. In the first reaction stage P1., at least the following steps are performed: P1.i. dissolving the corresponding selected 2-hydroxyarylcarbonyl derivative together with the corresponding indanone derivative or tetralone derivative in a weak acid, P1.ii. heating the mixture from P1.i. with the addition of a strong acid, P1.iii. cooling and washing the mixture from P1.ii. with a nonpolar aprotic solvent, P1.iv. separating the phase insoluble in the nonpolar aprotic solvent and placing the phase in water; B. In the second reaction stage P2., at least the following steps are performed: P2.i. Dye anion A n- An alkali metal salt and a nonpolar aprotic solvent are added to the aqueous solution from P1.iv., P2.ii. stirring and optionally heating the mixture from P2.i., separating off the aqueous phase and discarding it including the salts contained therein, P2.iii. washing the mixture from P2.ii. with water, preferably to the end point, and P2.iv. optionally removing the solvent under vacuum and optionally drying the benzopyrylium dye under vacuum.

7. Use of a benzopyrylium dye according to any one of claims 1 to 5 or prepared according to claim 6 in a photocurable formulation in combination with an electron donor for improving the bleaching properties of a photocurable material.

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

9. A layer structure comprising at least the following layers: A. Base layer A., ​​which is optionally part of another layer structure, B. A photopolymer layer B. comprising the photopolymer composition according to claim 8, and C. Optional covering layer C., which is optionally part of another layer structure.

10. A layer structure comprising at least the following layers: A. Base layer A., ​​which is optionally part of another layer structure, B. an exposed photopolymer layer B' produced by exposure of the photopolymer composition according to claim 8 to light, and C. Optional covering layer C., which is optionally part of another layer structure.

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

12. Hologram obtainable from a holographic medium according to any one of claims 10 or 11.

13. The hologram according to claim 12, characterized in that The hologram is selected from the group consisting of reflection, transmission, on-axis, off-axis, full aperture transmission, white light transmission, Denisyuk, off-axis reflection or side-lit holograms and holographic stereograms, preferably reflection, transmission or side-lit holograms, or a combination of at least two thereof.

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

15. Use of the photopolymer composition according to claim 8 for producing holographic media or holograms.

16. Use of the holographic medium according to claim 11 or 12 for producing chip cards, identification documents, 3D images, product protection labels, labels, banknotes or holographic optical elements, in particular holographic optical elements for optical displays, or in a medium for realizing a method selected from eye tracking, sensing, lidar, augmented reality, head-mounted displays, head-up displays and virtual reality applications, in particular virtual reality applications in the near infrared range and a combination of at least two thereof.

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