Triarylalkyl Borate Salts as Coinitiators in NIR Photopolymer Compositions

Abstract

The disclosure relates to photopolymer compositions including a) matrix polymers, b) writing monomers, c) at least one photoinitiator system, d) optionally at least one non-photopolymerizable component, e) optionally catalysts, radical stabilizers, solvents, additives, and other auxiliary agents and/or admixtures, where the at least one photoinitiator system c) consists of at least one dye and at least one coinitiator, at least one of the dyes has a structure according to formula (II), and the at least one coinitiator has a calculated oxidation potential which is ascertained according to the formula (1).

Claims

1. A photopolymer composition comprising a) matrix polymers, b) writing monomers, c) at least one photoinitiator system, d) optionally, at least one non-photopolymerizable component, e) optionally, catalysts, radical stabilizers, solvents, additives and other auxiliaries and/or adjuvants, wherein the at least one photoinitiator system c) consists of at least one dye and at least one coinitiator, wherein at least one of the dyes has a structure according to formula (II) ##STR00238## in which R.sup.205 stands for hydrogen, halogen, C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 alkoxy or NR.sup.210R.sup.211, R.sup.206 stands for hydrogen, halogen, C.sub.1 to C.sub.4 alkyl, C.sub.1 to C.sub.4 alkoxy or NR.sup.212R.sup.213, R.sup.201 to R.sup.204 and R.sup.210 to R.sup.213 each stand independently of each other for hydrogen, C.sub.1 to C.sub.16 alkyl, C.sub.4 to C.sub.7 cycloalkyl, C.sub.7 to C.sub.16 aralkyl, C.sub.6 to C.sub.10 aryl or a heterocyclic radical, NR.sup.201R.sup.202, NR.sup.203R.sup.204, NR.sup.210R.sup.211 and NR.sup.212R.sup.213 stand independently of each other for a five- or six-membered saturated ring attached via N, which may additionally contain an N or O and/or may be substituted by nonionic radicals, R.sup.207 to R.sup.209 stand independently of each other for hydrogen, C.sub.1 to C.sub.16 alkyl, C.sub.4 to C.sub.7 cycloalkyl, C.sub.7 to C.sub.16 aralkyl, C.sub.6 to C.sub.10 aryl, halogen or cyano, the two optional bridge groups X.sup.1 and X.sup.2 stand independently of each other for SiR.sup.214R.sup.215, CR.sup.216R.sup.217 or O, and R.sup.214 to R.sup.217 stand independently of each other for hydrogen or C.sub.1 to C.sub.4 alkyl and An.sup. stands for an anion selected from halide, perchlorate, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, tetraarylborate, triarylalkylborate, nitrate, cyanide, tosylate, trifluoromethylsulfonate, bis(trifluoromethyl)sulfonimide, azide, methylsulfonate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, hydrogensulfate, an arbitrarily substituted carboxylate, an arbitrarily substituted organic mono- or di-sulfonate, or an arbitrarily substituted organic mono- or di-carboxylate, and the at least one coinitiator has a calculated oxidation potential E.sub.ox.sup.calculated, determined according to the formula (1) below by the quantum mechanical calculation of the Gibbs energies at 298 K of the ground state and the oxidized state of the triarylalkylborate after geometry optimization, consisting of conformer energy minimization by means of the AM1 force field followed by ab initio conformer energy calculation based on the previously determined molecular geometry coordinates, in the solvent acetonitrile under solvent field correction according to the PCM method, in the range from 1.01 V to 1.31 V against the saturated calomel electrode (SCE) in acetonitrile $\begin{array}{cc}{E}_{ox}^{calculated}=-\frac{\left(G_{298}-G_{298}\left(\mathrm{oxidized}\right)\right)}{23.061\frac{\mathrm{kcal}}{\mathrm{mol}.Math.V}}+4.14V.& \left(1\right)\end{array}$

2. The photopolymer composition as claimed in claim 1, wherein the at least one dye has a structure of formula (II), in which R.sup.205 stands for hydrogen, C.sub.1 to C.sub.4 alkyl, or NR.sup.210R.sup.211, R.sup.206 stands for hydrogen, C.sub.1 to C.sub.4 alkyl, or NR.sup.212R.sup.213, R.sup.201 to R.sup.204 and R.sup.210 to R.sup.213 each stand independently of each other for hydrogen, methyl, ethyl, propyl, butyl, chloroethyl, cyanomethyl, cyanoethyl, methoxyethyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, benzyl, phenyl, tolyl, anisyl or chlorophenyl or NR.sup.201R.sup.202, NR.sup.203R.sup.204, NR.sup.210R.sup.211 and NR.sup.212R.sup.213 stand independently of each other for pyrrolidino, piperidino, morpholino or N-methylpiperazino, R.sup.207 to R.sup.209 stand for hydrogen and the two optional bridge groups X.sup.1 and X.sup.2 stand independently of each other for SiMe.sub.2 or O.

3. The photopolymer composition as claimed in claim 1, wherein the at least one dye has a structure of formula (XIX), ##STR00239## in which R.sup.201 to R.sup.204 and R.sup.210 to R.sup.213 each stand independently of each other for hydrogen or methyl, ethyl, propyl or butyl.

4. The photopolymer composition as claimed in claim 3, wherein the at least one dye according to formula (II) or formula (XIX) present has an organically substituted sulfonate as anion (An.sup.).

5. The photopolymer composition as claimed in claim 1, wherein the at least one coinitiator is a triarylalkylborate salt.

6. The photopolymer composition as claimed in claim 1, wherein the at least one coinitiator contains a triarylalkylborate salt of formula (III), wherein ##STR00240## A stands for a methylene group or for an arbitrarily substituted methine group, which can optionally form an up to 10-membered ring with R.sup.100, R.sup.100 is hydrogen or a C.sub.1 to C.sub.20 alkyl, C.sub.3 to C.sub.20 alkenyl, C.sub.3 to C.sub.20 alkynyl, C.sub.5 to C.sub.7 cycloalkyl or C.sub.7 to C.sub.13 aralkyl radical, optionally substituted by hydroxyl and/or alkoxy and/or acyloxy and/or halogen, R.sup.101, R.sup.102 and R.sup.103 each stand for up to five independently selected radicals from C.sub.1 to C.sub.20 alkyl, C.sub.3 to C.sub.5 alkenyl, C.sub.3 to C.sub.5 alkynyl, C.sub.5 to C.sub.7 cycloalkyl or C.sub.7 to C.sub.13 aralkyl radical, halogen, cyano, trifluoromethyl, trichloromethyl, difluoromethyl, dichloromethyl, trifluoromethylthioyl, trichloromethylthioyl, C.sub.1 to C.sub.12 alkoxy, trifluoromethoxy, trichloromethoxy, C.sub.1 to C.sub.12 alkylthioyl, thioyl, difluoromethoxy, difluoromethylthioyl, carboxyl, carbonyl, 2-, 3- or 4-pyridyl, or any substituted aryl radicals or hydrogen, the radicals being selected such that the radical-dependent calculated oxidation potential of the triarylalkylborate (III) is in a range between 1.01 V vs. SCE and 1.31 V vs. SCE in acetonitrile, K.sup.+ stands for an arbitrarily substituted organocation of valence n based on nitrogen, phosphorus, oxygen, sulfur, and/or iodine and n stands for 1, 2, or 3.

7. The photopolymer composition as claimed in claim 1, wherein R.sup.100 stands for a C.sub.1 to C.sub.20 alkyl, C.sub.5 to C.sub.7 cycloalkyl or C.sub.7 to C.sub.13 aralkyl radical and R.sup.101, R.sup.102 and R.sup.103 each stand for one or two independently selected radicals from C.sub.1 to C.sub.4 alkyl, halogen, cyano, trifluoromethyl, C.sub.1 to C.sub.4 alkoxy or arbitrarily substituted aryl radicals or hydrogen.

8. The photopolymer composition as claimed in claim 1, wherein R.sup.100 stands for a C.sub.3 to C.sub.12 alkyl radical and R.sup.101, R.sup.102 and R.sup.103 each stand for one to two, in meta- or para-position, independently selected radicals from C.sub.1 to C.sub.4 alkyl radicals and halogen substituents.

9. The photopolymer composition as claimed in claim 1, wherein the organocation K.sup.+ of the triarylalkylborate salt is a nitrogen- or phosphorus-based, mono- or divalent cation.

10. The photopolymer composition as claimed in claim 1, wherein the at least one coinitiator has an oxidation potential of between 1.01 V vs. SCE and 1.20 V vs. SCE in acetonitrile.

11. A layer structure containing at least the following layers: A. a substrate layer A, B. a photopolymer layer B formed from the polymer composition as claimed in claim 1, and C. a top layer C.

12. A layer structure containing at least the following layers: A. a substrate layer A, B. an exposed photopolymer layer B, produced from the photopolymer composition as claimed in claim 1 by curing by means of light, and C. a top layer C.

13. A holographic medium containing or obtainable using a photopolymer composition as claimed in claim 1.

14. The holographic medium as claimed in claim 13, wherein the hologram is selected from the group consisting of a reflection, transmission, in-line, off-axis, full-aperture transfer, white-light transmission, Denisyuk, off-axis reflection or edge-lit hologram and a holographic stereogram, it being likewise possible for combinations of these hologram types or plurality of holograms of the same type independently of each other to be united in the same volume of the holographic medium (multiplexing).

15. An optical display comprising a holographic medium as claimed in claim 13.

16. A method for producing chip cards, identity documents, 3D images, product protection tags, labels, banknotes or holographically optical elements comprising providing the holographic medium as claimed in claim 13.

17. A method for producing a holographic medium comprising providing the photopolymer composition as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows the holographic experimental setup with which the diffraction efficiency (DE) of the media was measured.

[0029] FIG. 2 shows the measured transmitted power P.sub.T (right y-axis) plotted as a solid line (here of Example 3a) against the angle detuning , the measured diffraction efficiency (left y-axis) plotted as filled circles against the angle detuning (as far as the finite size of the detector allowed), and the fitting to the Kogelnik theory as a dashed line (left y-axis).

DETAILED DESCRIPTION

[0030] The matrix polymer a) can be any matrix polymer a) which the person skilled in the art would select for the photopolymer composition according to the invention. Suitable matrix polymers a) of the photopolymer composition can be in particular crosslinked and, particularly preferably, three-dimensionally crosslinked.

[0031] It is preferred that the matrix polymers a) are polyurethanes, where the polyurethanes may be obtainable in particular by reacting at least one polyisocyanate component aI) with at least one isocyanate-reactive component aII).

[0032] The polyisocyanate component aI) preferably comprises at least one organic compound having at least two NCO groups. These organic compounds may in particular be monomeric di- and triisocyanates, polyisocyanates and/or NCO-functional prepolymers. The polyisocyanate component aI) may also contain or consist of mixtures of monomeric di- and triisocyanates, polyisocyanates and/or NCO-functional prepolymers.

[0033] Employable monomeric di- and triisocyanates include all of the compounds or mixtures thereof that are well known per se to the person skilled in the art. These compounds may have aromatic, araliphatic, aliphatic or cycloaliphatic structures. In minor amounts the monomeric di- and triisocyanates may also comprise monoisocyanates, i.e. organic compounds having one NCO group.

[0034] Examples of suitable monomeric di- and triisocyanates are butane 1,4-diisocyanate, pentane 1,5-diisocyanate, hexane 1,6-diisocyanate (hexamethylene diisocyanate, HDI), 2,2,4-trimethylhexamethylene diisocyanate and/or 2,4,4-trimethylhexamethylene diisocyanate (TMDI), isophorone diisocyanate (IPDI), 1,8-diisocyanato-4-(isocyanatomethyl)octane, bis(4,4-isocyanatocyclohexyl)methane and/or bis(2,4-isocyanatocyclohexyl)methane and/or mixtures thereof having any isomer content, cyclohexane 1,4-diisocyanate, the isomeric bis(isocyanatomethyl)cyclohexanes, 2,4- and/or 2,6-diisocyanato-1-methylcyclohexane (hexahydrotolylene 2,4- and/or 2,6-diisocyanate, H.sub.6-TDI), phenylene 1,4-diisocyanate, tolylene 2,4- and/or 2,6-diisocyanate (TDI), naphthylene 1,5-diisocyanate (NDI), diphenylmethane 2,4- and/or 4,4-diisocyanate (MDI), 1,3-bis(isocyanatomethyl)benzene (XDI) and/or the analogous 1,4 isomers or any desired mixtures of the aforementioned compounds.

[0035] Suitable polyisocyanates are compounds which have urethane, urea, carbodiimide, acylurea, amide, isocyanurate, allophanate, biuret, oxadiazinetrione, uretdione and/or iminooxadiazinedione structures and are obtainable from the aforementioned di- or triisocyanates.

[0036] More preferably, the polyisocyanates are oligomerized aliphatic and/or cycloaliphatic di- or triisocyanates, and it is especially possible to use the above aliphatic and/or cycloaliphatic di- or triisocyanates.

[0037] Very particular preference is given to polyisocyanates having isocyanurate, uretdione and/or iminooxadiazinedione structures and to biurets based on HDI or mixtures thereof.

[0038] Suitable prepolymers contain urethane and/or urea groups, and optionally further structures formed through modification of NCO groups as recited above. Prepolymers of this kind are obtainable, for example, by reaction of the abovementioned monomeric di- and triisocyanates and/or polyisocyanates all) with isocyanate-reactive compounds aII1).

[0039] Alcohols, amino or mercapto compounds, preferably alcohols, can be used as isocyanate-reactive compounds aII1). These may in particular be polyols. Very preferably, the isocyanate-reactive compound aII1) used may be polyester polyols, polyether polyols, polycarbonate polyols, poly(meth)acrylate polyols and/or polyurethane polyols.

[0040] Suitable polyester polyols are, for example, linear polyester diols or branched polyester polyols which can be obtained in a known manner by reacting aliphatic, cycloaliphatic or aromatic di- or polycarboxylic acids or the anhydrides thereof with polyhydric alcohols of OH functionality 2. Examples of suitable di- or polycarboxylic acids are polybasic carboxylic acids such as succinic acid, adipic acid, suberic acid, sebacic acid, decanedicarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, tetrahydrophthalic acid or trimellitic acid, and acid anhydrides such as phthalic anhydride, trimellitic anhydride or succinic anhydride, or any desired mixtures thereof. The polyester polyols may also be based on natural raw materials such as castor oil. It is likewise possible for the polyester polyols to be based on homo- or copolymers of lactones which are preferably obtainable by addition of lactones or lactone mixtures such as butyrolactone, -caprolactone and/or methyl--caprolactone onto hydroxy-functional compounds such as polyhydric alcohols of OH functionality 2, for example of the kind recited below.

[0041] Examples of suitable alcohols are all polyhydric alcohols such as, for example, the C.sub.2-C.sub.2 diols, the isomeric cyclohexanediols, glycerol or their arbitrary mixtures with each other.

[0042] Suitable polycarbonate polyols are accessible in a manner known per se by reaction of organic carbonates or phosgene with diols or diol mixtures.

[0043] Suitable organic carbonates are dimethyl, diethyl and diphenyl carbonates.

[0044] Suitable diols or mixtures comprise the polyhydric alcohols of OH functionality 2 mentioned per se in the context of the polyester segments, preferably butane-1,4-diol, hexane-1,6-diol and/or 3-methylpentanediol. Polyester polyols can also be converted into polycarbonate polyols.

[0045] Suitable polyether polyols are polyaddition products, optionally of blockwise construction, of cyclic ethers onto OH- or NH-functional starter molecules.

[0046] Suitable cyclic ethers are, for example, styrene oxides, ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, epichlorohydrin and arbitrary mixtures thereof.

[0047] Starters used may be the polyhydric alcohols of OH functionality 2 mentioned per se in the context of the polyester polyols, and also primary or secondary amines and amino alcohols.

[0048] Preferred polyether polyols are those of the aforementioned type based exclusively on propylene oxide, or random or block copolymers based on propylene oxide with further 1-alkylene oxides. Particularly preferred are propylene oxide homopolymers and also statistical or block copolymers which have oxyethylene, oxypropylene and/or oxybutylene units, where the proportion of the oxypropylene units based on the total amount of all oxyethylene, oxypropylene and oxybutylene units is at least 20 wt %, preferably at least 45 wt %. Oxypropylene and oxybutylene here comprise all respective linear and branched C.sub.3 and C.sub.4 isomers.

[0049] In addition, suitable constituents of the polyol component aII1), as polyfunctional isocyanate-reactive compounds, are also aliphatic, araliphatic or cycloaliphatic di-, tri- or polyfunctional alcohols of low molecular weight, i.e. having molecular weights 500 g/mol, and having short chains, i.e. containing 2 to 20 carbon atoms.

[0050] These may be, for example, in addition to the abovementioned compounds, neopentyl glycol, 2-ethyl-2-butylpropanediol, trimethylpentanediol, positionally isomeric diethyloctanediols, cyclohexanediol, cyclohexane-1,4-dimethanol, hexane-1,6-diol, cyclohexane-1,2- and -1,4-diol, hydrogenated bisphenol A, 2,2-bis(4-hydroxycyclohexyl)propane or 2,2-dimethyl-3-hydroxypropionic acid, 2,2-dimethyl-3-hydroxypropyl ester. Examples of suitable triols are trimethylolethane, trimethylolpropane or glycerol. Suitable higher-functionality alcohols are di(trimethylolpropane), pentaerythritol, dipentaerythritol or sorbitol.

[0051] It is particularly preferred for the polyol component to be a difunctional polyether, polyester or a polyether-polyester block copolyester or a polyether-polyester block copolymer with primary OH functions.

[0052] It is likewise possible to use amines as isocyanate-reactive compounds aIIl). Examples of suitable amines are ethylenediamine, propylenediamine, diaminocyclohexane, 4,4-dicyclohexylmethanediamine, isophoronediamine (IPDA), difunctional polyamines, for example the Jeffamines, amine-terminated polymers, in particular having number-average molar masses 10 000 g/mol. Mixtures of the aforementioned amines may also be used.

[0053] It is likewise possible to use amino alcohols as isocyanate-reactive compounds aII1). Examples of suitable amino alcohols are the isomeric aminoethanols, the isomeric aminopropanols, the isomeric aminobutanols and the isomeric aminohexanols or arbitrary mixtures thereof.

[0054] All the aforementioned isocyanate-reactive compounds aII1) can be mixed with one another as desired.

[0055] It is also preferable if the isocyanate-reactive compounds aII1) have a number-average molar mass of 200 and 10 000 g/mol, more preferably 500 and 8000 g/mol and very particularly preferably 800 and 5000 g/mol. The OH functionality of the polyols is preferably 1.5 to 6.0, particularly preferably 1.8 to 4.0.

[0056] The prepolymers of the polyisocyanate component aI) may in particular have a residual content of free monomeric di- and triisocyanates 1 wt %, particularly preferably 0.5 wt % and very preferably 0.3 wt %.

[0057] It may also be possible for the polyisocyanate component aI) to contain, in full or in part, an organic compound wherein the NCO groups have been fully or partly reacted with blocking agents known from coating technology. Examples of blocking agents are alcohols, lactams, oximes, malonic esters, pyrazoles and amines, for example butanone oxime, diisopropylamine, diethyl malonate, ethyl acetoacetate, 3,5-dimethylpyrazole, -caprolactam or mixtures thereof.

[0058] It is particularly preferred if the polyisocyanate component aI) comprises compounds with aliphatically bonded NCO groups, where aliphatically bonded NCO groups are understood to mean those groups that are bonded to a primary C atom. The isocyanate-reactive component aII) preferably comprises at least one organic compound which has on average at least 1.5 and preferably 2 to 3 isocyanate-reactive groups. In the context of the present invention, isocyanate-reactive groups are preferably considered to be hydroxyl, amino or mercapto groups.

[0059] The isocyanate-reactive component may in particular comprise compounds having a numerical average of at least 1.5 and preferably 2 to 3 isocyanate-reactive groups.

[0060] Suitable polyfunctional, isocyanate-reactive compounds of component aII) are, for example, the compounds aII1) described above.

[0061] In another preferred embodiment, it is provided that the substance catalyzing the polyurethane formation comes from the group of tin-based organyls, or is one based on iron(II), iron(III), gallium(III), bismuth(III), vanadium(III), vanadium(IV), terbium(III), tin(II), zinc(II), zirconium(IV) complex with suitable mono- or bidentate ligands.

[0062] The writing monomer b) can be any writing monomer that the person skilled in the art would select for the photopolymer composition according to the invention. Preferably, the writing monomer b) comprises or consists of at least one mono- and/or one multifunctional writing monomer. Further preferably, the writing monomer b) may comprise or consist of at least one mono- and/or one multifunctional (meth)acrylate writing monomer. Very preferably, the writing monomer may comprise or consist of at least one mono- and/or one multifunctional urethane (meth)acrylate.

[0063] Suitable acrylate writing monomers are especially compounds of the general formula (IV)

##STR00003##

in which m1 and m4 and R.sup.5 is a linear, branched, cyclic or heterocyclic organic moiety which is unsubstituted or else optionally substituted by heteroatoms and/or R.sup.6 is hydrogen or a linear, branched, cyclic or heterocyclic organic moiety which is unsubstituted or else optionally substituted by heteroatoms. More preferably, R.sup.6 is hydrogen or methyl and/or R.sup.5 is a linear, branched, cyclic or heterocyclic organic moiety which is unsubstituted or else optionally substituted by heteroatoms.

[0064] Acrylates and methacrylates refer in the present context, respectively, to esters of acrylic acid and methacrylic acid. Examples of preferably usable acrylates and methacrylates are phenyl acrylate, phenyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxyethoxyethyl acrylate, phenoxyethoxyethyl methacrylate, phenylthioethyl acrylate, phenylthioethyl methacrylate, 2-naphthyl acrylate, 2-naphthyl methacrylate, 1,4-bis(2-thionaphthyl)-2-butyl acrylate, 1,4-bis(2-thionaphthyl)-2-butyl methacrylate, bisphenol A diacrylate, bisphenol A dimethacrylate, and their ethoxylated analog compounds or N-carbazolyl acrylates.

[0065] Urethane acrylates are understood in the present context to mean compounds having at least one acrylic ester group and at least one urethane bond. Such compounds can be obtained, for example, by reacting a hydroxy-functional acrylate or methacrylate with an isocyanate-functional compound.

[0066] Examples of isocyanate-functional compounds which can be used for this purpose are monoisocyanates and also the monomeric diisocyanates, triisocyanates and/or polyisocyanates stated under al). Examples of suitable monoisocyanates are phenyl isocyanate, the isomeric methylthiophenyl isocyanates. Di-, tri- or polyisocyanates are mentioned above, as are triphenylmethane 4,4,4-triisocyanate and tris(p-isocyanatophenyl) thiophosphate or derivatives thereof having a urethane, urea, carbodiimide, acylurea, isocyanurate, allophanate, biuret, oxadiazinetrione, uretdione or iminooxadiazinedione structure and mixtures thereof. Aromatic di-, tri- or polyisocyanates are preferred here.

[0067] Hydroxy-functional acrylates or methacrylates for the preparation of urethane acrylates are, for example, compounds such as 2-hydroxyethyl (meth)acrylate, polyethylene oxide mono(meth)acrylates, polypropylene oxide mono(meth)acrylates, polyalkylene oxide mono(meth)acrylates, poly(-caprolactone) mono(meth)acrylates, such as Tone M100 (Dow, Schwalbach, DE), 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxy-2,2-dimethylpropyl (meth)acrylate, hydroxypropyl (meth)acrylate, acrylic acid 2-hydroxy-3-phenoxypropyl ester, the hydroxy-functional mono-, di- or tetraacrylates of polyhydric alcohols such as trimethylolpropane, glycerol, pentaerythritol, dipentaerythritol, ethoxylated, propoxylated or alkoxylated trimethylolpropane, glycerol, pentaerythritol, dipentaerythritol or technical mixtures thereof. Preference is given to 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate and poly(-caprolactone) mono(meth)acrylate.

[0068] Likewise possible for use are the conventional hydroxyl group-containing epoxy (meth)acrylates with OH contents from 20 to 300 mg KOH/g or hydroxyl group-containing polyurethane (meth)acrylates with OH contents from 20 to 300 mg KOH/g or acrylated polyacrylates with OH contents from 20 to 300 mg KOH/g and also their mixtures with each other and mixtures with hydroxyl group-containing unsaturated polyesters and also mixtures with polyester (meth)acrylates or mixtures of hydroxyl group-containing unsaturated polyesters with polyester (meth)acrylates.

[0069] Preferably, urethane acrylates in particular are obtainable from the reaction of tris(p-isocyanatophenyl) thiophosphate and/or m-methylthiophenyl isocyanate with alcohol-functional acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate and/or hydroxybutyl (meth)acrylate or reaction products of 2-isocyanatoethyl acrylate and/or 2-isocyanatoethyl methacrylate and/or 1,1-(bisacryloyloxymethyl)ethyl isocyanate with optionally arbitrarily substituted naphthols.

[0070] It is also possible that the writing monomer b) comprises or consists of further unsaturated compounds such as ,-unsaturated carboxylic acid derivatives such as, for example, maleates, fumarates, maleimides, acrylamides, additionally vinyl ether, propenyl ether, allyl ether and compounds containing dicyclopentadienyl units, and also olefinically unsaturated compounds such as styrene, -methylstyrene, vinyltoluene and/or olefins, for example.

[0071] The at least one photoinitiator system c) can be any photoinitiator system which the person skilled in the art would select for the photopolymer composition according to the invention. Photoinitiators of component c) are usually compounds activatable by actinic radiation, which can trigger polymerization of the writing monomers. The photoinitiators can be differentiated as unimolecular (type I) and bimolecular (type II) initiators. In addition, they are distinguished in terms of their chemical nature into photoinitiators for radical, anionic, cationic or mixed modes of polymerization.

[0072] Type I photoinitiators (Norrish type I) for radical photopolymerization on irradiation form free radicals through unimolecular bond scission. Examples of type I photoinitiators are triazines, oximes, benzoin ethers, benzil ketals, bis-imidazoles, aroylphosphine oxides, sulfonium salts and iodonium salts.

[0073] Type II photoinitiators (Norrish type II) for radical polymerization consist of a dye as sensitizer and a coinitiator and undergo a bimolecular reaction when irradiated with light adapted to the dye. First, the dye absorbs a photon and transfers energy from an excited state to the coinitiator. The latter releases the polymerization-initiating radicals through electron or proton transfer or direct hydrogen abstraction.

[0074] The type II photoinitiators are preferably used.

[0075] Such photoinitiator systems are described in principle in EP 0 223 587 A and preferably consist of a mixture of one or more dyes.

[0076] Suitable NIR chromophores, which together with a compound of formula (III) form a type II photoinitiator, are, for example, the cationic dyes described in EP 0438123.

[0077] Furthermore, pentamethine cyanine and heptamethine cyanine dyes, hemicyanine dyes, merocyanine dyes, oxonols and neutrocyanine dyes are understood and preferred as cationic NIR dyes. Dyes of this kind are 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, T. Gessner, U. Mayer in Ullmann's Encyclopedia of Industrial Chemistry, Triarylmethane and Diarylmethane Dyes, Wiley-VCH Verlag, 2000.

[0078] Pentamethine cyanine and heptamethine cyanine dyes are particularly preferred.

[0079] Especially preferred for a cationic NIR dye is the dye Karenz IR-T, available from Showa Denko, with the following structural formula (V):

##STR00004##

[0080] Preferred anions (An.sup.) of the cationic NIR dyes are, in particular, C.sub.8- to C.sub.25-alkanesulfonate, preferably C.sub.13- to C.sub.25-alkanesulfonate, C.sub.3- to C.sub.18-perfluoroalkanesulfonate, C.sub.4- to C.sub.18-perfluoroalkanesulfonate which in the alkyl chain carries at least 3 hydrogen atoms, C.sub.9- to C.sub.25-alkanoate, C.sub.9- to C.sub.25-alkenoate, C.sub.8- to C.sub.25-alkylsulfate, preferably C.sub.13- to C.sub.25-alkylsulfate, C.sub.8- to C.sub.25-alkenylsulfate, preferably C.sub.13- to C.sub.25-alkenylsulfate, C.sub.3- to C.sub.18-perfluoroalkylsulfate, C.sub.4- to C.sub.18-perfluoroalkylsulfate which in the alkyl chain carries at least 3 hydrogen atoms, polyethersulfates based on at least 4 equivalents of ethylene oxide and/or 4 equivalents of propylene oxide, bis-C.sub.4- to C.sub.25-alkyl-, C.sub.5- to C.sub.7-cycloalkyl-, C.sub.3- to C.sub.8-alkenyl- or C.sub.7- to C.sub.11-aralkyl-sulfosuccinate, bis-C.sub.2- to C.sub.10-alkyl-sulfosuccinate substituted by at least 8 fluorine atoms, C.sub.8- to C.sub.25-alkyl-sulfoacetates, benzenesulfonate substituted by at least one radical from the group of halogen, C.sub.4- to C.sub.25-alkyl, perfluoro-C.sub.1- to C.sub.8-alkyl and/or C.sub.1- to C.sub.12-alkoxycarbonyl, naphthalene- or biphenylsulfonate optionally substituted by nitro, cyano, hydroxy, C.sub.1- to C.sub.25-alkyl, C.sub.1- to C.sub.12-alkoxy, amino, C.sub.1- to C.sub.12-alkoxycarbonyl or chlorine, benzene-, naphthalene- or biphenyldisulfonate optionally substituted by nitro, cyano, hydroxy, C.sub.1- to C.sub.25-alkyl, C.sub.1- to C.sub.12-alkoxy, C.sub.1- to C.sub.12-alkoxycarbonyl or chlorine, benzoate substituted by dinitro, C.sub.6- to C.sub.25-alkyl, C.sub.4- to C.sub.12-alkoxycarbonyl, benzoyl, chlorobenzoyl or toluoyl, the anion of naphthalenedicarboxylic acid, diphenyl ether disulfonate, sulfonated or sulfated, optionally at least monounsaturated C.sub.8- to C.sub.25-fatty acid esters of aliphatic C.sub.1- to C.sub.8-alcohols or glycerol, bis-(sulfo-C.sub.2- to C.sub.6-alkyl)-C.sub.3- to C.sub.12-alkanedicarboxylic esters, bis-(sulfo-C.sub.2- to C.sub.6-alkyl)-itaconic esters, (sulfo-C.sub.2- to C.sub.6-alkyl)-C.sub.6- to C.sub.18-alkanecarboxylic esters, (sulfo-C.sub.2- to C.sub.6-alkyl)-acrylic or -methacrylic esters, triscatecholphosphate optionally substituted by up to 12 halogen radicals, an anion from the group of tetraphenylborate, cyanotriphenylborate, tetraphenoxyborate, C.sub.4- to C.sub.12-alkyl-triphenylborate, in which the phenyl- or phenoxy radicals may be substituted by halogen, C.sub.1- to C.sub.4-alkyl and/or C.sub.1- to C.sub.4-alkoxy, C.sub.4- to C.sub.12-alkyl-trinaphthylborate, tetra-C.sub.1- to C.sub.20-alkoxyborate, 7,8- or 7,9-dicarbanidoundecaborate(1-) or (2-), which are optionally substituted on the B and/or C atoms by one or two C.sub.1- to C.sub.12-alkyl or phenyl groups, dodecahydrodicarbadodecaborate(2-) or BC.sub.1- to C.sub.12-alkyl-C-phenyl-dodecahydrodicarbadodecaborate(1-), where in the case of polyvalent anions such as naphthalenedisulfonate, An.sup. stands for one equivalent of this anion, and where the alkane and alkyl groups may be branched and/or may be substituted by halogen, cyano, methoxy, ethoxy, methoxycarbonyl or ethoxycarbonyl.

[0081] Preferably, the anions described in WO 2012062655 are used as An.sup..

[0082] It is also preferable if the anion An.sup. of the dye has an AC log P in the range from 1 to 30, more preferably in the range from 1 to 12 and especially preferably in the range from 1 to 6.5. The AC log P is calculated according to J. Comput. Aid. Mol. Des. 2005, 19, 453; Virtual Computational Chemistry Laboratory, http://www.vcclab.org.

[0083] Suitable coinitiators for a type II photoinitiator system are anionic borates, especially anionic triarylalkylborates, which are described in WO 2015/055576. Other coinitiators may be pentacoordinated silicates or tertiary aromatic amines.

[0084] In a preferred embodiment of the photopolymer composition, the at least one dye has the structure of the formula (II), in which

[0085] R.sup.205 stands for hydrogen, C.sub.1 to C.sub.4 alkyl, or NR.sup.210R.sup.211,

[0086] R.sup.206 stands for hydrogen, C.sub.1 to C.sub.4 alkyl, or NR.sup.212R.sup.213,

[0087] R.sup.201 to R.sup.204 and R.sup.210 to R.sup.213 each stand independently of each other for hydrogen, methyl, ethyl, propyl, butyl, chloroethyl, cyanomethyl, cyanoethyl, methoxyethyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, benzyl, phenyl, tolyl, anisyl or chlorophenyl or

[0088] NR.sup.201R.sup.202, NR.sup.203R.sup.204, NR.sup.210R.sup.211 and NR.sup.212R.sup.213 stand independently of each other for pyrrolidino, piperidino, morpholino or N-methylpiperazino,

[0089] R.sup.207 to R.sup.209 stand for hydrogen and

[0090] the two optional bridge groups X.sup.1 and X.sup.2 stand independently of each other for SiMe.sub.2 or O.

[0091] In a preferred embodiment of the photopolymer composition, the at least one dye has a structure of the formula (XVX):

##STR00005## [0092] in which R.sup.201 to R.sup.20 and R.sup.210 to R.sup.213 stand independently of each other for hydrogen or methyl, ethyl, propyl or butyl.

[0093] In a preferred embodiment of the photopolymer composition, the at least one dye according to formula (I) or formula (XVX) present has an organically substituted sulfonate as anion (An.sup.).

[0094] In a preferred embodiment of the photopolymer composition, the at least one coinitiator is a triarylalkylborate salt.

[0095] In a preferred embodiment of the photopolymer composition, the coinitiator contains a triarylalkylborate according to the formula (III), which has a calculated oxidation potential of between 1.01 V vs. SCE and 1.31 V vs. SCE in acetonitrile and

##STR00006## [0096] in which [0097] A stands for a methylene group or for an arbitrarily substituted methine group, which can optionally form an up to 10-membered ring with R.sup.10, [0098] R.sup.100 is hydrogen or a C.sub.1 to C.sub.20 alkyl, C.sub.3 to C.sub.20 alkenyl, C.sub.3 to C.sub.20 alkynyl, C.sub.5 to C.sub.7 cycloalkyl or C.sub.7 to C.sub.13 aralkyl radical, optionally substituted by hydroxyl and/or alkoxy and/or acyloxy and/or halogen, [0099] R.sup.101, R.sup.102 and R.sup.103 each stand for up to five independently selected radicals from C.sub.1 to C.sub.20 alkyl, C.sub.3 to C.sub.5 alkenyl, C.sub.3 to C.sub.5 alkynyl, C.sub.5 to C.sub.7 cycloalkyl or C.sub.7 to C.sub.13 aralkyl radical, halogen, cyano, trifluoromethyl, trichloromethyl, difluoromethyl, dichloromethyl, trifluoromethylthioyl, trichloromethylthioyl, C.sub.1 to C.sub.12 alkoxy, trifluoromethoxy, trichloromethoxy, C.sub.1 to C.sub.12 alkylthioyl, thioyl, difluoromethoxy, difluoromethylthioyl, carboxyl, carbonyl, 2-, 3- or 4-pyridyl, or any substituted aryl radicals or hydrogen, the radicals being selected such that the radical-dependent calculated oxidation potential of the triarylalkylborate (III) is in a range between 1.01 V vs. SCE and 1.31 V vs. SCE in acetonitrile, [0100] K.sup.+ stands for an arbitrarily substituted organocation of valence n based on nitrogen, phosphorus, oxygen, sulfur, and/or iodine and [0101] n stands for 1, 2, or 3.

[0102] In this embodiment of the photopolymer composition, A is preferably a methylene group.

[0103] In a preferred embodiment of the photopolymer composition, for the triarylalkylborate of structure (III), R.sup.100 stands for a C.sub.1 to C.sub.20 alkyl, C.sub.5 to C.sub.7 cycloalkyl or C.sub.7 to C.sub.13 aralkyl radical and R.sup.101, R.sup.102 and R.sup.103 stand for respectively one or two radicals selected independently of one another from C.sub.1 to C.sub.4 alkyl, halogen, cyano, trifluoromethyl, C.sub.1 to C.sub.4 alkoxy or arbitrarily substituted aryl radicals or hydrogen. Preferably, at least one radical selected from the radicals R.sup.101, R.sup.102 and R.sup.103 is not hydrogen. Preferably, in the case of two R.sup.101, two R.sup.102 and two R.sup.103 radicals, the two radicals are each arranged in meta position and para position to the B atom on the aromatic moiety. Preferably, in this embodiment, A stands for a methylene group.

[0104] Furthermore, for the triarylalkylborate of structure (II), R.sup.100 stands preferably for C.sub.3 to C.sub.5 alkyl radical, where A is preferably a methylene group and at least one of the radicals R.sup.101, R.sup.102 and R.sup.103 stands for in each case one to two, in meta and/or para position, radicals selected independently of one another from C.sub.1 to C.sub.4 alkyl radicals and halogen substituents, preferably at least R.sup.102 and/or R.sup.103 independently of one another stand for selected halogen substituents, where halogen substituents include not only halogen radicals such as Cl radical or F radical but also trihaloalkyl radicals, in particular trihalomethyl radicals and trihaloethyl radicals, in particular trifluoromethyl radicals and trichloromethyl radicals.

[0105] In another preferred embodiment of the photopolymer composition, for the triarylalkylborate of structure (II), R.sup.100 stands for a C.sub.3 to C.sub.12 alkyl radical, R.sup.101, R.sup.102, and R.sup.103 independently of each other stand for one to two, meta- or para-positioned radicals selected from the group consisting of C.sub.1- to C.sub.4 alkyl radicals and halogen substituents, preferably at least R.sup.102 and/or R.sup.103 stand for a halogen substituent. In the case of two R.sup.101, two R.sup.102 and two R.sup.103 radicals, the two radicals are preferably in each case in meta position and para position to the B atom. Preferably, in this embodiment, A stands for a methylene group.

[0106] Furthermore, preferably, for the triarylalkylborate of structure (II), R.sup.100 stands for C.sub.3 to C.sub.5 alkyl radical, where A is preferably a methylene group and R.sup.101, R.sup.102 and R.sup.103 each stand for one to two, in meta and/or para position, radicals selected independently of one another from C.sub.1 to C.sub.4 alkyl radicals and halogen substituents, preferably at least R.sup.102 and/or R.sup.103 stand for a halogen substituent.

[0107] The following triarylalkylborates are very particularly preferred, where each K.sup.+ is any organocation based on nitrogen, phosphorus, oxygen, sulfur or iodine:

##STR00007## ##STR00008## ##STR00009##

[0108] In a preferred embodiment of the photopolymer composition, the organocation K.sup.+ of the triarylalkylborate salt is a nitrogen- or phosphorus-based, mono- or divalent cation, preferably a nitrogen-based mono- or divalent cation, particularly preferably a monovalent ammonium cation.

[0109] In a preferred embodiment of the photopolymer composition, the at least one coinitiator, in particular in interaction with one of the previously described cationic dyes, has an oxidation potential calculated according to formula (1) in acetonitrile against the saturated calomel electrode in a range between 1.01 V vs. SCE and 1.20 V vs. SCE in acetonitrile, preferably between 1.01 V vs. SCE and 1.17 V vs. SCE and particularly preferably between 1.01 V vs. SCE and 1.15 V vs. SCE.

[0110] In addition, K.sup.+ can be an organocation of valence n based on nitrogen, such as ammonium ions, pyridinium ions, pyridazinium ions, pyrimidinium ions, pyrazinium ions, imidazolium ions, pyrrolidinium ions, which optionally carry in one or more side chains further functional groups such as ethers, esters, amides and/or carbamates and which may also be present in oligomeric or polymeric or bridging form.

[0111] Preferably, K.sup.+ is an organocation of valence n based on phosphorus, such as an arbitrarily substituted tetraalkyl-phosphonium, trialkyl-aryl-phosphonium, dialkyl-diaryl-phosphonium, alkyl-triaryl-phosphonium, or tetraaryl-phosphonium cation, which optionally carries in one or more side chains further functional groups such as carbonyls, amides and/or carbamates and which may also be present in oligomeric or polymeric or bridging form.

[0112] Further preferably, K.sup.+ is an organocation of valence n based on oxygen, such as an arbitrarily substituted pyrylium cation, which may also be present in annelated form such as in the benzopyrylium, flavylium, naphthoxanthenium cation, or a polymeric cation having the stated substitution patterns.

[0113] More preferably, K.sup.+ is an organocation of valence n based on sulfur, such as an onium compound of sulfur which may carry identical or different optionally substituted C.sub.4 to C.sub.14 alkyl, C.sub.6 to C.sub.10 aryl, C.sub.7 to C.sub.12 arylalkyl or C.sub.5 to C.sub.6 cycloalkyl radicals and/or establish oligomeric or polymeric repeating connecting units to construct sulfonium salts where 1n3, or such as thiopyrylium cations or polymeric cations having the stated substitution patterns.

[0114] Further preferably, K.sup.+ is an organocation of valence n based on iodine, such as an onium compound of iodine which may carry identical or different optionally substituted C.sub.1 to C.sub.22 alkyl, C.sub.6 to C.sub.14 aryl, C.sub.7 to C.sub.15 arylalkyl or C.sub.5 to C.sub.7 cycloalkyl radicals and/or establish oligomeric or polymeric repeating connecting units to construct iodonium salts where 1n3, or such as further polymeric cations having the stated substitution patterns.

[0115] The photoinitiator system may also contain a further coinitiator cIII) such as trichloromethyl initiators, iodonium salts, sulfonium salts, aryl oxide initiators, bisimidazole initiators, ferrocene initiators, oxime initiators, thiol initiators or peroxide initiators.

[0116] It may be advantageous to use mixtures of these coinitiators and various dyes. Depending on the radiation source used, the type and concentration of the PIS must be adapted in a manner known to the person skilled in the art. For more information, see for example P. K. T. Oldring (Ed.), Chemistry & Technology of UV & EB Formulations For Coatings, Inks & Paints, Vol. 3, 1991, SITA Technology, London, pp. 61-328. It is particularly preferred if the PIS comprises a combination of dyes with absorption spectra which at least partially cover the spectral range from 400 to 1200 nm, with at least one coinitiator tuned to the dyes. It is also preferred if at least one photoinitiator suitable for a laser light color is contained in the photopolymer composition. It is further preferred also if the photopolymer composition contains a suitable photoinitiator for each of at least two laser light colors selected from blue, green and red and NIR. Finally, it is especially preferred if the photopolymer composition contains a suitable photoinitiator for each of the laser light colors.

[0117] The at least one non-photopolymerizable component d) may be any component d) which the person skilled in the art would select for the photopolymer composition according to the invention. It is preferably provided that the photopolymer composition additionally contains urethanes as additives of component d), where the urethanes can be substituted in particular by at least one fluorine atom.

[0118] Preferably, the urethanes may have the general formula (XVIII)

##STR00010##

in which o1 and o8 and R.sup.7, R.sup.8 and R.sup.9 are linear, branched, cyclic or heterocyclic unsubstituted or else optionally heteroatom-substituted organic radicals and/or R.sup.8, R.sup.9 independently of one another are hydrogen, with preferably at least one of the radicals R.sup.7, R.sup.8, R.sup.9 being substituted by at least one fluorine atom and particularly preferably R.sup.7 being an organic radical having at least one fluorine atom. Particularly preferably, R.sup.9 is a linear, branched, cyclic or heterocyclic organic radical which is unsubstituted or else optionally substituted by heteroatoms such as fluorine.

[0119] Preferred is a photopolymer containing a photopolymer composition, in particular comprising matrix polymers, a writing monomer and a photoinitiator system which additionally contains a compound of the formula (XVIII).

[0120] The statements made above with regard to the photopolymer composition according to the invention with regard to further preferred embodiments also apply analogously to the photopolymer according to the invention.

[0121] Another subject of the present invention relates to a layer structure comprising at least the following layers: [0122] A. a substrate layer A, which may be part of a further layer structure, [0123] B. a photopolymer layer B, formed from the photopolymer composition according to the invention, and [0124] C. a top layer C, which may be part of the further layer structure.

[0125] Another subject of the present invention relates to a layer structure comprising at least the following layers: [0126] A. a substrate layer A, which may be part of a further layer structure, [0127] B. an exposed or cured photopolymer layer B, produced from the photopolymer composition according to the invention by curing by means of light, and [0128] C. a top layer C, which may be part of the further layer structure.

[0129] A method for producing a holographic medium using a disclosed photopolymer composition is further disclosed. The photopolymer compositions can be used in particular for the production of holographic media in the form of a film. In this case, as carrier A, a stratum of a material transparent for light in the visible and NIR spectral range (transmission greater than 85% in the wavelength range from 400 to 1200 nm) or of such an assembly of materials is coated in the dark with the photopolymer composition B on one or both sides and, optionally, with a covering layer C applied on the one or more photopolymer strata B. Preferred materials or material assemblies for the carrier are based on polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene, polypropylene, cellulose acetate, cellulose hydrate, cellulose nitrate, cycloolefin polymers, polystyrene, polyepoxides, polysulfone, 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. Material assemblies may be film laminates or coextrudates. Preferred material assemblies are duplex and triplex films constructed according to one of the schemes A/B, A/B/A or A/B/C. Particular preference is given to PC/PET, PET/PC/PET and PC/TPU (TPU=thermoplastic polyurethane). The materials or material assemblies of the carrier may have been given a non-stick, antistatic, hydrophobized or hydrophilized finish on one or both sides. The stated modifications are used on the side facing the photopolymer layer B for the purpose that the photopolymer stratum B can be detached from the carrier A non-destructively. A modification of the side of the carrier facing away from the photopolymer stratum B serves to ensure that the media according to the invention meet specific mechanical requirements, which are required, for example, for processing in roller laminators, in particular in roll-to-roll processes.

[0130] In addition, a further method for producing a holographic medium using a photopolymer composition according to the invention is disclosed, which also provides holographic media in the form of films. In this case, as carrier A, a stratum of a material transparent for light in the visible and NIR spectral range (transmission greater than 85% in the wavelength range from 400 to 1200 nm) or of such an assembly of materials is applied in the dark with the photopolymer composition B on one side via 2D printing and, optionally, with a covering layer C on the one or more photopolymer strata B. All common inkjet technologies can be used here. If desired, in a targeted way, only the areas required for the function can be printed with the photopolymer composition B. Preferred materials or material assemblies of the carrier are based on glass, silicon (in the form of the 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, polysulfone, 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. Material assemblies may be film laminates or coextrudates. Preferred material assemblies are duplex and triplex films constructed according to one of the schemes A/B, A/B/A or A/B/C. Particular preference is given to PC/PET, PET/PC/PET and PC/TPU (TPU=thermoplastic polyurethane). The materials or material assemblies of the carrier may have been given a non-stick, antistatic, hydrophobized or hydrophilized finish on one or both sides. The stated modifications are used on the side facing the photopolymer layer B for the purpose that the photopolymer stratum B can be detached from the carrier A non-destructively. A modification of the side of the carrier facing away from the photopolymer stratum B serves to ensure that the media according to the invention meet specific mechanical requirements, which are required, for example, for processing in roller laminators, in particular in roll-to-roll processes.

[0131] Further disclosed are material assemblies according to the type described above, comprising a photoexposed, preferably light-cured photopolymer layer B, so forming duplex and triplex films according to a scheme A/B, A/B/A or A/B/C.

[0132] It is possible to expose holographic information into such holographic media.

[0133] Another subject of the invention relates to a holographic medium containing a photopolymer composition according to the invention. Holographic media can be processed to holograms by appropriate exposure processes for optical applications in the red and NIR range (600-1200 nm). Visual holograms and holograms operating in the NIR range include all holograms that can be recorded by methods known to the person skilled in the art. These include in-line (Gabor) holograms, 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 or transmission holograms are preferred.

[0134] Another subject of the invention relates to a holographic medium which has been converted into a hologram, the hologram being selected from the group consisting of a reflection, transmission, in-line, off-axis, full-aperture transfer, white-light transmission, Denisyuk, off-axis reflection or edge-lit hologram and a holographic stereogram, preferably reflection, transmission or edge-lit hologram or a combination of at least two thereof, it being likewise possible for combinations of these hologram types or plurality of holograms of the same type independently of each other to be united in the same volume of the holographic medium (multiplexing).

[0135] Possible optical functions of the holograms which can be produced with the photopolymer compositions according to the invention correspond to the optical functions of light elements such as lenses, mirrors, deflecting mirrors, filters, diffuser lenses, diffraction elements, diffusers, light guides, waveguides, projection lenses and/or masks. Combinations of these optical functions can also be combined independently of one another in a hologram (multiplexing). Often these optical elements show a frequency selectivity, depending on how the holograms were exposed and what dimensions the hologram has.

[0136] Above-described functions of the holograms producible with the photopolymer compositions according to the invention are used for example, but not exclusively, in the areas of eye tracking, sensing, and also LIDAR and augmented reality, head-mounted display and virtual reality applications in the NIR range.

[0137] Another subject of the invention relates to an optical display comprising a holographic medium according to the invention.

[0138] In addition, it is also possible by means of the holographic media to produce holographic images or diagrams, for example for personal portraits, biometric representations in security documents, or generally images or image structures for advertising, security labels, brand protection, branding, labels, design elements, decorations, illustrations, collectible cards, pictures and the like, and pictures that can represent digital data, including in combination with the products detailed above. 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, on the (also moving) light source with which, etc., it is illuminated. Because of this variety of possible designs, holograms, especially volume holograms, constitute an attractive technical solution for the abovementioned application.

[0139] Another subject of the invention relates to the use of a holographic medium according to the invention for producing chip cards, identity documents, 3D images, product protection tags, labels, banknotes or holographically optical elements, in particular for optical displays or in media for the realization of methods selected from the group consisting of eye tracking, sensing, LIDAR, augmented reality, head-mounted display and virtual reality applications, in particular in the near infrared range, and a combination of at least two thereof.

[0140] The holographic media can be used for recording of in-line, off-axis, full-aperture transfer, white light transmission, Denisyuk, off-axis reflection or edge-lit holograms and also of holographic stereograms, especially for production of optical elements, images or image representations.

[0141] Holograms are accessible from holographic media according to the invention by means of appropriate exposure.

EXAMPLES AND DESCRIPTION OF FIGURES

[0142] The following examples are used to explain the invention by way of illustration without limiting it to them.

Measurement of the OH Number and the NCO Value:

[0143] OH number: The specified OH numbers were determined in accordance with DIN 53240-2. [0144] NCO value: The specified NCO values (isocyanate contents) were determined in accordance with DIN EN ISO 11909.

Measurement of the Holographic Properties DE and an of the Holographic Media/Photopolymer Films by Means of Two-Beam Interference in a Reflection Arrangement:

[0145] The beam of an NIR laser (emission wavelength 850 nm) was converted into a parallel homogeneous beam using the space filter (SF) and together with the collimating lens (CL). The final cross sections of the signal and reference beam are fixed by the iris diaphragms (I). The diameter of the iris aperture is 0.4 cm. The polarization-dependent beam splitters (PBS) divide the laser beam into two coherent, equally polarized beams. The power of the reference beam was set to 1.75 mW and the power of the signal beam to 2.25 mW via the /2 plates. The powers were determined using the semiconductor detectors (D) with the sample removed. The angle of incidence (.sub.0) of the reference beam is 21.8, and the angle of incidence (.sub.0) of the signal beam is 41.8. The angles are measured proceeding from the sample normal to the beam direction. According to Scheme 1, therefore, .sub.0 has a negative sign and .sub.0 has a positive sign. At the location of the sample (medium), the interference field of the two overlapping beams produced a pattern of light and dark strips perpendicular to the angle bisectors of the two beams incident on the sample (reflection hologram). The strip spacing , also called grating period, in the medium is 296 nm (the refractive index of the medium assumed to be 1.51).

[0146] FIG. 1 shows the holographic experimental setup with which the diffraction efficiency (DE) of the media was measured, with FIG. 1 representing the geometry of a holographic media tester (HMT) at =850 nm (NIR laser) (M=mirror, S=shutter, SF=space filter, CL=collimator lens, /2=/2 plate, PBS=polarization-sensitive beam splitter, D=detector, I=iris, .sub.0=21.8, .sub.0=41.8 are the incidence angles of the coherent beams measured outside the sample (of the medium), RD=reference direction of the turntable).

[0147] Holograms were written into the medium in the following manner: [0148] Both shutters (S) are open for exposure time t. [0149] Thereafter, the medium was allowed 5 minutes' time for the diffusion of the as yet unpolymerized writing monomers, with closed shutters (S).

[0150] The written holograms were then read out in the following manner. The shutter of the signal beam remained closed. The shutter of the reference beam was open. The iris diaphragm of the reference beam was closed to a diameter of <1 mm. This ensured that the beam was always completely within the previously written hologram for all angles of rotation () of the medium. The turntable, under computer control, then swept over the angle range from .sub.min to .sub.max with an angle step width of 0.05. is measured from the sample normal to the reference direction of the turntable. The reference direction of the turntable is obtained when the angles of incidence of the reference beam and of the signal beam have the same absolute value during writing of the hologram, i.e. .sub.0=31.8 and .sub.0=31.8. In that case, .sub.recording=0. For .sub.0=21.8 and .sub.0=41.8, Q.sub.recording is therefore 10. In general, for the interference field during writing (recording) of the hologram:

[00002]$\begin{array}{cc}{}_0={}_0+{}_{recording}.& \left(3\right)\end{array}$

[0151] .sub.0 is the half-angle in the laboratory system outside the medium and during writing of the hologram:

[00003]$\begin{array}{cc}{}_0=\frac{{}_0-{}_0}{2}& \left(4\right)\end{array}$

[0152] In this case, therefore, .sub.0=31.8. At each setting for the angle of rotation , the powers of the beam transmitted into the zeroth order were measured by means of the corresponding detector D, and the powers of the beam diffracted in the first order by means of the detector D. The diffraction efficiency was calculated at each setting of angle as the quotient of:

[00004]$\begin{array}{cc}=\frac{P_D}{P_D+P_T}& \left(5\right)\end{array}$

[0153] P.sub.D is the power in the detector of the diffracted beam and P.sub.T is the power in the detector of the transmitted beam.

[0154] By means of the method described above, the Bragg curve, which describes the diffraction efficiency as a function of the rotation angle , of the written hologram, was measured and stored in a computer. In addition, the intensity transmitted into the zeroth order was also recorded against the rotation angle and stored in a computer.

[0155] The maximum diffraction efficiency (DE=.sub.max) of the hologram, i.e., its peak value, was determined at .sub.reconstruction. In some cases, it was necessary for this purpose to change the position of the detector for the diffracted beam in order to determine this maximum value.

[0156] The refractive index contrast n and the thickness d of the photopolymer layer were then determined using the Coupled Wave Theory (see: H. Kogelnik, The Bell System Technical Journal, volume 48, November 1969, number 9, page 2909-page 2947) to the measured Bragg curve and the angular course of the transmitted intensity. It should be noted that due to the shrinkage of thickness caused by photopolymerization, the strip spacing of the hologram and the orientation of the strips (slant) may deviate from the strip spacing of the interference pattern and its orientation. Accordingly, the angle .sub.0 or the corresponding angle of the turntable .sub.reconstruction at which maximum diffraction efficiency is achieved will also deviate from .sub.0 or from the corresponding Q.sub.recording. This alters the Bragg condition. This alteration is taken into account in the evaluation process. The evaluation process is described hereinafter:

[0157] All geometric quantities that refer to the written hologram and not to the interference pattern are represented as quantities with primes.

[0158] For the Bragg curve () of a reflection hologram, according to Kogelnik:

[00005]$\begin{array}{cc}=\{\begin{array}{c}\frac{1}{1-\frac{1-{\left(/\right)}^2}{{\sin }^2(\sqrt{{}^2-{}^2)}}},\mathrm{for}{}^2-{}^2<0\\ \frac{1}{1+\frac{1-{\left(/\right)}^2}{{\sinh }^2(\sqrt{{}^2-{}^2)}}},\mathrm{for}{}^2-{}^{2}0\end{array}& \left(6\right)\end{array}$$\mathrm{with}:$$\begin{array}{cc}=\frac{.Math.n.Math.d^{}}{.Math.\sqrt{.Math.c_s.Math.c_r.Math.}}& \left(7\right)\end{array}$$\begin{array}{cc}=-\frac{d}{2.Math.c_s}.Math.\mathrm{DP}& \left(8\right)\end{array}$$\begin{array}{cc}{c}_s=\cos \left({}^{}\right)-\cos \left({}^{}\right).Math.\frac{}{n.Math.{}^{}}& \left(9\right)\end{array}$$\begin{array}{cc}{c}_r=\cos \left({}^{}\right)& \left(10\right)\end{array}$$\begin{array}{cc}\mathrm{DP}=\frac{}{{}^{}}.Math.\left(2.Math.\cos \left({}^{}-{}^{}\right)-\frac{}{n.Math.{}^{}}\right)& \left(11\right)\end{array}$$\begin{array}{cc}{}^{}=\frac{{}^{}+{}^{}}{2}& \left(12\right)\end{array}$$\begin{array}{cc}{}^{}=\frac{}{2.Math.n.Math.\cos \left({}^{}-{}^{}\right)}& \left(13\right)\end{array}$

[0159] When the hologram is read out (reconstruction), the following applies, in analogy to above:

[00006]$\begin{array}{cc}{}_0^{}={}_0+& \left(14\right)\end{array}$$\begin{array}{cc}\sin \left({}_0^{}\right)=n.Math.\sin \left({}^{}\right)& \left(15\right)\end{array}$

[0160] At the Bragg condition, the dephasing is DP=0. And it follows correspondingly that:

[00007]$\begin{array}{cc}{}_0^{}={}_0+{}_{reco\mathrm{nstruction}}& \left(16\right)\end{array}$$\begin{array}{cc}\sin \left({}_0^{}\right)=n.Math.\sin \left({}^{}\right)& \left(17\right)\end{array}$

[0161] The still unknown angle can be determined by comparing the Bragg condition of the interference field when writing the hologram and the Bragg condition when reading out the hologram, assuming that only thickness shrinkage occurs. It then follows that:

[00008]$\begin{array}{cc}\sin \left({}^{}\right)=\frac{1}{n}.Math.\left[\sin \left({}_0\right)+\sin \left({}_0\right)-\sin \left({}_0+{}_{reco\mathrm{nstruction}}\right)\right]& \left(18\right)\end{array}$

[0162] is the grating intensity, is the detuning parameter, and is the orientation (slant) of the refractive index grating that was written. and correspond to the angles .sub.0 and .sub.0 of the interference field on writing of the hologram, but measured in the medium and valid for the grating of the hologram (after shrinkage of thickness). n is the mean refractive index of the photopolymer and was set to 1.51. is the wavelength of the laser light in a vacuum.

[0163] The maximum diffraction efficiency (DE=.sub.max) for =0 is then:

[00009]$\begin{array}{cc}\mathrm{DE}={\tanh }^2\left(\right)={\tanh }^2\left(\frac{.Math.n.Math.d^{}}{.Math.\sqrt{\cos \left({}^{}\right).Math.\cos \left({}^{}-2{}^{}\right)}}\right)& \left(19\right)\end{array}$

[0164] The measured data for the diffraction efficiency, the theoretical Bragg curve and the transmitted intensity are, as shown in FIG. 2, plotted against the centered angle of rotation .sub.reconstruction=.sub.0.sub.0, also called angle detuning. FIG. 2 shows the measured transmitted power P.sub.T (right y-axis) plotted as a solid line (here of Example 3a) against the angle detuning , the measured diffraction efficiency (left y-axis) plotted as filled circles against the angle detuning Q (as far as the finite size of the detector allowed), and the fitting to the Kogelnik theory as a dashed line (left y-axis).

[0165] As DE is known, the shape of the theoretical Bragg curve according to Kogelnik is only determined by the thickness d of the photopolymer layer. n is corrected via DE for given thickness d in such a way that measurement and theory of DE always match. d is now adjusted until the angular positions of the first minor minima of the theoretical Bragg curve correspond to the angular positions of the first minor maxima of the transmitted intensity and also until the full width at half maximum (FWHM) for the theoretical Bragg curve and for the transmitted intensity match.

[0166] Since the direction in which a reflection hologram also rotates when reconstructed by means of an scan, but the detector for the diffracted light can cover only a finite angle range, the Bragg curve of broad holograms (small d) is not fully covered in an scan, but rather only the central region, given suitable detector positioning. Therefore, the shape of the transmitted intensity, which is complementary to the Bragg curve, is additionally employed for adjustment of the layer thickness d.

[0167] FIG. 2 shows the plot of the Bragg curve i according to the Coupled Wave Theory (broken line), the measured diffraction efficiency (filled circles) and the transmitted power (black solid line) against the angle detuning .

[0168] For a formulation, this procedure may have been repeated several times for different exposure times t on different media in order to determine that mean energy dose of the incident laser beam at which DE passes into the saturation value on writing of the hologram. The mean energy dose E is obtained as follows from the powers of the two partial beams assigned to the angles .sub.0 and .sub.0 (reference beam with P.sub.r=1.75 mW and signal beam with P.sub.s=2.25 mW), the exposure time t and the diameter of the iris diaphragm (0.4 cm):

[00010]$\begin{array}{cc}E\left(\mathrm{mJ}/{\mathrm{cm}}^2\right)=\frac{2.Math.\left[P_r+P_s\right].Math.t\left(s\right)}{.Math.0.4^2{\mathrm{cm}}^2}& \left(20\right)\end{array}$

[0169] The powers of the component beams were adjusted such that the same power density is attained in the medium at the angles .sub.0 and .sub.0 used.

Calculation of the Oxidation Potential of Triarylalkylborates:

[0170] The absolute oxidation potential (E.sub.ox.sup.calculated), referenced against the saturated calomel electrode, was calculated using the following formula (2):

[00011]$\begin{array}{cc}{E}_{ox}^{calculated}=-\frac{(G_{298}-G_{298}\left(\mathrm{oxidized}\right)}{n_{e}F}-E_{1/2}^{0,\mathrm{SHE}}+E_{1/2}^{0,\mathrm{SCE}}& \left(2\right)\end{array}$

[0171] Here, n.sub.e is the number of transferred electrons (here always n.sub.e=1), F is the Faraday constant (F=23.061 kcal mol.sup.1 V.sup.1), E.sub.1/2.sup.0,SCE the absolute potential of the standard hydrogen electrode (SHE) (E.sub.1/2.sup.0,SHE=4281 V), E.sub.1/2.sup.0,SHE the potential of the saturated calomel electrode (SCE) relative to the SHE in acetonitrile (E.sub.1/2.sup.0,SCE=0.141 V) and G.sub.298 and G.sub.298(oxidized) each the calculated Gibbs energies at 298 K of the ground state and of the oxidized state of the triarylalkylborate.

[0172] The formula (2) can also be expressed as follows after the above-stated constants have been inserted (formula (1)):

[00012]$\begin{array}{cc}{E}_{ox}^{calculated}=-\frac{\left(G_{298}-G_{298}\left(\mathrm{oxidized}\right)\right)}{23.061\frac{\mathrm{kcal}}{\mathrm{mol}.Math.V}}+4.14V.& \left(1\right)\end{array}$

[0173] The calculation of the Gibbs energies at 298 K of the ground state and of the oxidized state was carried out according to the following procedure: First, using ChemDraw 3D, the three-dimensional molecular geometry of the triarylalkylborate was generated and this geometry was subjected to a conformer analysis. The conformers found were energetically minimized by means of the AM1 force field and the coordinates of the molecular geometries obtained (usually only one conformer was obtained) were used for the calculation of the electronic energy. The electronic ground state was geometry-optimized in a suitable solvent (PCM approach for acetronitrile) and the absolute electronic energies of the optimized structures were determined and corrected for the influence of the solvent field (G.sub.298). Subsequently, the thus-optimized molecular geometry was reduced by one electron and the absolute electronic energy of the oxidized moleculealso calculated in acetonitrile (PCM method)was determined again (G.sub.298(oxidized)).

Substances:

[0174] The solvents, reagents and all bromoaromatics used were purchased from chemical suppliers. The bromoaromatics were freshly distilled where appropriate. Anhydrous solvents contain 50 ppm of water. [0175] Polyol 1 was prepared with an OH number of 56.8, as described in WO2015091427. [0176] Desmodur N 3900 product of Covestro AG, Leverkusen, DE, hexanediisocyanate-based polyisocyanate, iminooxadiazinedione content at least 30%, NCO content: 23.5%. [0177] Iron(III) trifluoroacetylacetonate [14526-22-8] is available from ABCR GmbH & Co. KG, Karlsruhe, Germany. [0178] Urethane acrylate 1 (phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisacrylate, [1072454-85-3]) was prepared as described in WO2015091427. [0179] Urethane acrylate 2 (2-({[3-(methylsulfanyl)phenyl]carbamoyl}oxy)-ethyl prop-2-enoate, [1207339-61-4]) was prepared as described in WO2015091427. [0180] Additive 1 bis(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl)-(2,2,4-trimethylhexane-1,6-diyl)biscarbamate [1799437-41-4] was prepared as described in WO2015091427. [0181] Karenz IR-T purchased from Showa Denko EUROPE GmbH, [96233-24-8]. [0182] Karenz P3B purchased from Showa Denko EUROPE GmbH, [120307-06-4]. [0183] Cation 2 N.sub.1,N.sub.22-dihexadecyl-N.sub.1,N.sub.1,N.sub.22,N.sub.22,10,10,13-heptamethyl-7,16-dioxo-3,6,17,20-tetraoxa-8,15-diazadocosane-1,22-diaminium dibromide was prepared as described in WO 2018087064. [0184] BYK-310 silicone-containing surface additive, product of BYK-Chemie GmbH, Wesel, Germany.

Synthesis Protocols:

Preparation protocol for N-ethyl-N-[4-[1,5,5-tris[4-(diethylamino)phenyl]-2,4-pentadienylidene]-2,5-cyclohexadien-1-ylidene]ethanaminium bis(2-ethylhexyl)sulfosuccinate (dye 1)

[0185] 4.08 g of sodium bis(2-ethylhexyl)sulfosuccinate (1.0 eq.) were dissolved in 80 mL of deionized water. 7.44 g of Karenz IR-T (1.0 eq.) in 100 mL of butyl acetate were added to this solution and the two-phase mixture was stirred for 3 h at RT. The aqueous phase was then separated off and the organic phase was washed with five times 80 mL of deionized water. Finally, the solvent was removed under vacuum on a rotary evaporator and the product was obtained as a dark blue resin (9.50 g, 98% of theory).

Preparation of N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium chloride (cation 1)

[0186] 1.28 mol of dimethylcetylamine were dissolved in 2.4 L of tert-butyl methyl ether (MTBE) in a 5 L flange vessel at 30 C. 1.28 mol of 3-chlorophenylpropane were added dropwise to this solution at a rate such that the reaction temperature does not exceed 40 C. After the end of metered addition, the reaction solution was stirred for 5 h at 90 C., then cooled to 40 C. over the period of 1 h and transferred to suitable vessels for crystallization. The crystals that formed overnight were isolated, washed with 500 mL of cold MTBE and dried. A colorless solid was obtained (450 g, 83% of theory) with a melting point at 59 C.

Preparation protocol for tetrabutylammonium triarylalkylborates with R.SUP.101.=R.SUP.102.=R.SUP.103

##STR00011##

[0187] In a four-neck flask with thermometer, reflux condenser, dropping funnel and magnetic stirrer, the corresponding diisopropylalkylborate (1.0 eq.) and magnesium turnings (3 eq.) were introduced in a solvent mixture consisting of dry toluene and dry THF (5.8:1, 1.9 M). This mixture is stirred for 30 min at room temperature. The corresponding bromoaromatic (3 eq.) is then initially added dropwise, undiluted, to the mixture until ensuing exothermy signals the start of reaction, but a maximum of 10% of the undiluted bromoaromatic is used for this purpose. The rest of the bromoaromatic is added dropwise to the reaction solution in a solvent mixture consisting of dry toluene and dry THF (1:1, dilution of total molarity to 0.4 M) at a rate such that the reaction temperature does not exceed 45 C. After the end of addition, the reaction solution is heated under reflux to full dissolution of the magnesium or 1 h. The reaction solution is cooled to room temperature and discharged onto a mixture of ice water and tetrabutylammonium bromide (1 eq.). The mixture is stirred for 1 h and then the organic phase is separated off. The organic phase is washed with water until a halide test (HNO.sub.3 (aq., 10%)+AgNO.sub.3) is negative. The solvents are removed in vacuo on a rotary evaporator and the crude product is recrystallized from methanol.

Preparation protocol for tetrabutylammonium triarylalkylborates with R.SUP.101.=R.SUP.102.R.SUP.103

[0188] In a four-neck flask with thermometer, reflux condenser, dropping funnel and magnetic stirrer, the corresponding diisopropylalkylborate (1.0 eq.) and magnesium turnings (3 eq.) were introduced in a solvent mixture consisting of dry toluene and dry THF (4:1, 1.9 M). This mixture is stirred for 30 min at room temperature. The first bromoaromatic (1 eq.) is then initially added dropwise, undiluted, to the mixture until ensuing exothermy signals the start of reaction, but a maximum of 10% of the undiluted bromoaromatic is used for this purpose. The rest of the bromoaromatic is added dropwise to the reaction solution in a solvent mixture consisting of dry toluene and dry THF (1.1:1, dilution of total molarity to 0.7 M) at a rate such that the reaction temperature does not exceed 45 C. After complete addition, the reaction solution is stirred for 1 h at RT. The corresponding second bromoaromatic is then initially added dropwise, undiluted, to the mixture until ensuing exothermy signals the start of reaction, but a maximum of 10% of the undiluted bromoaromatic is used for this purpose. The rest of the bromaromatic in the residual solvent mixture consisting of dry toluene and dry THF (1.1:1, dilution of total molarity to 0.4 M) is again added dropwise to the reaction solution at a rate such that the reaction temperature does not exceed 45 C. After the end of addition, the reaction solution is heated under reflux to full dissolution of the magnesium or 1 h. The reaction solution is cooled to room temperature and discharged onto a mixture of ice water and tetrabutylammonium bromide (1 eq.). The mixture is stirred for 1 h and the organic phase is separated off. The organic phase is washed with water until a halide test (HNO.sub.3 (aq., 10%)+AgNO.sub.3) is negative. The solvents are removed in vacuo on a rotary evaporator and the crude product is recrystallized from methanol.

Preparation Protocol for Triarylalkylborates with Cations of Valence n=1

[0189] The corresponding tetrabutylammonium triarylalkylborate (1 eq.) is dissolved in butyl acetate (0.04 M) and admixed with an aqueous solution of the corresponding cation (halide salt, 1.05 eq., 0.05 M) and sodium bis(2-ethylhexyl)sulfosuccinate (0.05 eq.) and the mixture is stirred for 1 h at RT. After phase separation, the organic phase is washed repeatedly with water until a halide test (HNO.sub.3 (aq., 10%)+AgNO.sub.3) is negative. The solvent is removed in vacuo on a rotary evaporator and the product is dried under reduced pressure.

Preparation Protocol for Triarylalkylborates with Cations of Valence n=2

[0190] The corresponding tetrabutylammonium triarylalkylborate (1 eq.) is dissolved in butyl acetate (0.04 M) and admixed with an aqueous solution of the corresponding cation (halide salt, 0.525 eq., 0.05 M) and sodium bis(2-ethylhexyl)sulfosuccinate (0.05 eq.) and the mixture is stirred for 1 h at RT. After phase separation, the organic phase is washed repeatedly with water until a halide test (HNO.sub.3 (aq., 10%)+AgNO.sub.3) is negative. The solvent is removed in vacuo on a rotary evaporator and the product is dried under reduced pressure.

Production Protocol for Photopolymer Film/Holographic Media

[0191] 14.9 g of the polyol component 1 described above are melted and mixed in the dark with 6.6 g of urethane acrylate 1, 6.6 g of urethane acrylate 2 described above, 9.2 g of the fluorinated urethane described above (additive 1), 0.45 g of the respective borate salt described above, 0.10 g of dye 1, 0.12 g of BYK-310, 0.01 g of iron(III) trifluoroacetylacetonate, 10.5 g of ethyl acetate, 1.1 g of butyl acetate and 7.7 g of 1-methoxy-2-propyl acetate to give a homogeneous solution. Then 2.8 g of Desmodur N 3900 are added and mixing is repeated. This solution is placed in the dark on a roll-to-roll coating line onto a 60 m thick TAC film and applied by means of a doctor blade in such a way that a wet film thickness range of 14-17 m is achieved. At a drying temperature of 80 C. and in a drying time of around 4 minutes, the coated film is dried and then protected with a 40 m thick polyethylene film. This film is then packaged in a light-protected manner.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate

[0192] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102R.sup.103, 3-chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate. Subsequently, in accordance with the general preparation protocol for triarylhexylborates with cations of valence n=1, the resulting tetrabutylammonium triarylhexylborate was reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate. A colorless oil (18.92 g, 42% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.6 ppm. The calculated reduction potential was E.sub.ox=1.02 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate (Example 3a in Table 2)

[0193] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate as coinitiator.

Preparation of N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate

[0194] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102R.sup.103, 3-chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate. Subsequently, the general preparation protocol for triarylalkylborates with cations of valence n=1 was followed using cation 1. A colorless oil (2.5 g, 42% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.6 ppm. The calculated reduction potential was E.sub.ox=1.02 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate (Example 3b in Table 2)

[0195] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium di(3-chloro-4-methyl-phenyl)(4-methylphenyl)hexylborate as a coinitiator.

Preparation of tributyltetradecylphosphonium di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate

[0196] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102R.sup.103, 3-chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate. Subsequently, the general preparation protocol for triarylalkylborates with cations of valence n=1 was followed using tributyltetradecylphosphonium bromide. A colorless oil (1.2 g, 42% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.6 ppm. The calculated reduction potential was E.sub.ox=1.02 V vs. SCE in acetonitrile.

Preparation of a photopolymer with tributyltetradecylphosphonium di(3-chloro-4-methyl-phenyl)(4-methylphenyl)hexylborate (Example 3c in Table 2)

[0197] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with tributyltetradecylphosphonium di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate as a coinitiator.

Preparation of N.SUB.1.,N.SUB.22.-dihexadecyl-N.SUB.1.,N.SUB.1.,N.SUB.22.,N.SUB.22.,10,10,13-heptamethyl-7,16-dioxo-3,6,17,20-tetraoxa-8,15-diazadocosane-1,22-diaminium bis-di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate

[0198] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102R.sup.103, 3-chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate. Subsequently, the general preparation protocol for triarylalkylborates with cations of valence n=1 were followed using cation 2. A colorless oil (2.7 g, 42% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.6 ppm. The calculated reduction potential was E.sub.ox=1.02 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N.SUB.1.,N.SUB.22.-dihexadecyl-N.SUB.1.,N.SUB.1.,N.SUB.22.,N.SUB.22.,10,10,13-heptamethyl-7,16-dioxo-3,6,17,20-tetraoxa-8,15-diazadocosane-1,22-diaminium bis-di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate (Example 3d in Table 2)

[0199] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N.sub.1,N.sub.22-dihexadecyl-N.sub.1,N.sub.1,N.sub.22,N.sub.22,10,10,13-heptamethyl-7,16-dioxo-3,6,17,20-tetraoxa-8,15-diazadocosane-1,22-diaminium bis-di(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate as a coinitiator.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium di(4-chlorophenyl)(4-methyl-phenyl)hexylborate

[0200] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102R.sup.103, 4-chlorobromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate. Subsequently, in accordance with the general preparation protocol for triarylhexylborates with cations of valence n=1, the resulting tetrabutylammonium triarylhexylborate was reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate. A colorless oil (2.4 g, 60% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.7 ppm. The calculated reduction potential was E.sub.ox=1.03 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium di(4-chlorophenyl)(4-methylphenyl)hexylborate (Example 8 in Table 2)

[0201] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium di(4-chlorophenyl)(4-methyl-phenyl)hexylborate as a coinitiator.

Preparation of N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)cyclohexylborate

[0202] The preparation protocol for the preparation of tetrabutylammonium tri(3-chloro-4-methylphenyl)cyclohexylborate, published in WO2018/087064, was followed. Subsequently, the general preparation protocol for triarylalkylborates with cations of valence n=1 was followed using cation 1. A slightly yellowish oil (5.0 g, 99% of theory) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=8.7 ppm. The calculated reduction potential was E.sub.ox=1.03 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)cyclohexylborate (Example 11 in Table 2)

[0203] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenylcyclohexylborate as a coinitiator.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium diphenyl(3-chloro-4-methylphenyl)hexylborate

[0204] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102R.sup.103, bromobenzene (2 eq.) and 3-chloro-4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate. The product of the reaction was obtained after a silica gel column chromatography (dichloromethane/toluene 70:30). Subsequently, in accordance with the general preparation protocol for triarylhexylborates with cations of valence n=1, the resulting tetrabutylammonium triarylhexylborate was reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate. A colorless oil (0.68 g, 76% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.4 ppm. The calculated reduction potential was E.sub.ox=1.04 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium diphenyl(3-chloro-4-methylphenyl)hexylborate (Example 12 in Table 2)

[0205] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium diphenyl(3-chloro-4-methylphenyl)hexylborate as a coinitiator.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium diphenyl(4-fluorophenyl)hexylborate

[0206] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102R.sup.103, bromobenzene (2 eq.) and 4-fluorobromobenzene (1 eq.) were reacted with diisopropylhexyl borate. The product of the reaction was obtained after a silica gel column chromatography (dichloromethane/toluene 70:30). Subsequently, in accordance with the general preparation protocol for triarylalkylborates with cations of valence n=1, the resulting tetrabutylammonium triarylhexylborate was reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate. A colorless oil (0.74 g, 34% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.5 ppm. The calculated reduction potential was E.sub.ox=1.06 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium diphenyl(4-fluorophenyl)hexylborate (Example 15 in Table 2)

[0207] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium diphenyl(4-fluorophenyl)hexylborate as a coinitiator.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)-3-phenylpropylborate

[0208] The preparation protocol for the preparation of tetrabutylammonium tri(3-chloro-4-methylphenyl)-3-phenylpropylborate, published in WO2018/087064, was followed. Subsequently, in accordance with the general preparation protocol for triarylalkylborates with cations of valence n=1, the resulting tetrabutylammonium triarylalkylborate was reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate. A slightly yellowish oil (4.8 g, 99% of theory) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.3 ppm. The calculated reduction potential was E.sub.ox=1.11 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)-3-phenylpropylborate (Example 38 in Table 2)

[0209] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)-3-phenylpropyl borate as a coinitiator.

Preparation of tetrabutylammonium tri(4-fluorophenyl)dodecylborate

[0210] The preparation protocol for the preparation of tetrabutylammonium tri(4-fluorophenyl)dodecylborate, published in WO2018/087064, was followed. Colourless oil (8.9 g, 12% of theory) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.4 ppm. The calculated reduction potential was E.sub.ox=1.13 V vs. SCE in acetonitrile.

Preparation of a photopolymer with tetrabutylammonium tri(4-fluorophenyl)dodecylborate (Example 41 in Table 2)

[0211] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with tetrabutylammonium tri-(4-fluorophenyl)dodecylborate as a coinitiator.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)hexylborate

[0212] The preparation protocol published in WO 2018/099698 was followed. The calculated reduction potential was E.sub.ox=1.15 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)hexylborate (Example 48 in Table 2)

[0213] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)hexylborate as a coinitiator.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)butylborate

[0214] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102=R.sup.103, 3-chloro-4-methylbromobenzene was reacted with diisopropylbutyl borate. Subsequently, in accordance with the general preparation protocol for triarylalkylborates with cations of valence n=1, the resulting tetrabutylammonium triarylbutylborate was reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate. A colorless oil (2.4 g, 24% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.6 ppm. The calculated reduction potential was E.sub.ox=1.15 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)butylborate (Example 49 in Table 2)

[0215] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chloro-4-methylphenyl)butylborate as a coinitiator.

Preparation of tetrabutylammonium tri(4-chlorophenyl)hexylborate

[0216] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102=R.sup.103, 4-chlorobromobenzene was reacted with diisopropylhexyl borate. Colorless crystals (56 g, 50% of theory) were obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=9.9 ppm. The calculated reduction potential was E.sub.ox=1.17 V vs. SCE in acetonitrile.

Preparation of a photopolymer with tetrabutylammonium tri(4-chlorophenyl)hexylborate (Example 56 in Table 2)

[0217] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with tetrabutylammonium tri(4-chlorophenyl)hexylborate as a coinitiator.

Preparation of N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium triphenylbutylborate

[0218] In accordance with the general production protocol for triarylalkylborates with cations of valence n=1, tetrabutylammonium triphenylbutylborate (Karenz P3B) was reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate to give N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium triphenylbutylborate. A colorless amorphous solid (54 g, >99% of theory) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.3 ppm. The calculated reduction potential was E.sub.ox=1.00 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N,N-dimethyl-N-(3-phenylpropyl)hexadecyl ammonium triphenylbutylborate (Example NEB1 in Table 2)

[0219] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium triphenylbutylborate as a coinitiator.

Preparation of N-benzyl-N,N-dimethylhexadecylammonium tri(3-chlorophenyl)hexylborate

[0220] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102=R.sup.103, 3-chlorobromobenzene was reacted with diisopropylhexyl borate. Subsequently, the general preparation protocol for triarylalkylborates with cations of valence n=1 was followed using N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate. A colorless oil (2.5 g, 50% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.1 ppm. The calculated reduction potential was E.sub.ox=1.32 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chlorophenyl)hexylborate (Example NEB2 in Table 2)

[0221] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N-benzyl-N,N-dimethylhexadecylammonium tri(3-chlorophenyl)hexylborate as a coinitiator.

Preparation of N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium tri(4-trifluoromethylphenyl)hexylborate

[0222] In accordance with the general preparation protocol for tetrabutylammonium triarylalkylborates with R.sup.101=R.sup.102=R.sup.103, 4-bromobenzene trifluoride was reacted with diisopropylhexyl borate. Subsequently, the general production protocol for triarylalkylborates with cations of valence n=1 was followed using cation 1. A colorless oil (2.5 g, 22% of theory over two stages) was obtained with a signal in the .sup.11B NMR spectrum at (ppm) (CDCl.sub.3)=10.0 ppm. The calculated reduction potential was E.sub.ox=1.45 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium tri(4-trifluoromethylphenyl)hexylborate (Example NEB3 in Table 2)

[0223] In accordance with the general production protocol for photopolymer films, a photopolymer was prepared with N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium tri(4-trifluoromethylphenyl)hexylborate as a coinitiator.

EXAMPLES

[0224] The oxidation potential of different trialkylaryl borates according to the invention and not according to the invention was calculated by means of the above-stated method for calculating the oxidation potential of triarylalkylborates with the software package GAMESS (G. MJ. Barca, C. Bertoni, L. Carrington, D. Datta, N. De Silva, J. E. Deustua, D. G. Fedorov, J. R. Gour, A. O. Gunina, E. Guidez, T. Harville, S. Irle, J. Ivanic, K. Kowalski, S. S. Leang, H. Li, W. L., J. J. Lutz, I. Magoulas, J. Mato, V. Mironov, H. Nakata, B. Q. Pham, P. Piecuch, D. Poole, S. R. Pruitt, A. P. Rendell, L. B. Roskop, K. Ruedenberg, T. Sattasathuchana, M. W. Schmidt, J. Shen, L. Slipchenko, M. Sosonkina, V. Sundriyal, A. Tiwari, J. L. Galvez Vallejo, B. Westheimer, M. Wloch, P. Xu, F. Zahariev, M. S. Gordon; J. Chem. Phys. 152; 154102 (2020)). The results of these calculations are listed in the following table. For the calculation of the oxidation potential, the cation of the corresponding trialkylarylborate is irrelevant, and so the values listed below apply to salts of the following general structure:

##STR00012##

where K.sup.+ or K.sup.2+ represents any ammonium or phosphonium cation.

TABLE-US-00001 TABLE 1 Oxidation potentials of various triarylalkylborate anions calculated according to formula (1), where the specified radicals refer to the above general structure of formula (24) and the oxidation potential in V is reported in comparison to the saturated calomel electrode in the solvent acetonitrile. Ex- E.sub.ox am- (calc- ple R.sup.100 R.sup.101 R.sup.102 R.sup.103 ulated) 1 n-hexyl [00013] [00014] [00015] 1.01 2 n-hexyl [00016] [00017] [00018] 1.01 3 n-hexyl [00019] [00020] [00021] 1.02 4 n-hexyl [00022] [00023] [00024] 1.02 5 n-hexyl [00025] [00026] [00027] 1.02 6 n-hexyl [00028] [00029] [00030] 1.02 7 n-hexyl [00031] [00032] [00033] 1.02 8 n-hexyl [00034] [00035] [00036] 1.03 9 n-hexyl [00037] [00038] [00039] 1.03 10 n-hexyl [00040] [00041] [00042] 1.03 11 cyclohexyl [00043] [00044] [00045] 1.03 12 n-hexyl [00046] [00047] [00048] 1.04 13 n-hexyl [00049] [00050] [00051] 1.04 14 n-hexyl [00052] [00053] [00054] 1.05 15 n-hexyl [00055] [00056] [00057] 1.06 16 n-hexyl [00058] [00059] [00060] 1.06 17 n-hexyl [00061] [00062] [00063] 1.06 18 n-hexyl [00064] [00065] [00066] 1.07 19 n-hexyl [00067] [00068] [00069] 1.07 20 n-hexyl [00070] [00071] [00072] 1.07 21 n-hexyl [00073] [00074] [00075] 1.07 22 n-hexyl [00076] [00077] [00078] 1.07 23 n-hexyl [00079] [00080] [00081] 1.08 24 n-hexyl [00082] [00083] [00084] 1.08 25 n-hexyl [00085] [00086] [00087] 1.08 26 n-hexyl [00088] [00089] [00090] 1.08 27 n-hexyl [00091] [00092] [00093] 1.08 28 n-hexyl [00094] [00095] [00096] 1.09 29 n-hexyl [00097] [00098] [00099] 1.09 30 n-hexyl [00100] [00101] [00102] 1.09 31 n-hexyl [00103] [00104] [00105] 1.09 32 n-hexyl [00106] [00107] [00108] 1.09 34 n-hexyl [00109] [00110] [00111] 1.10 35 n-hexyl [00112] [00113] [00114] 1.10 33 n-hexyl [00115] [00116] [00117] 1.11 36 n-hexyl [00118] [00119] [00120] 1.11 37 n-hexyl [00121] [00122] [00123] 1.11 38 phenylpropyl [00124] [00125] [00126] 1.11 39 n-hexyl [00127] [00128] [00129] 1.12 40 n-hexyl [00130] [00131] [00132] 1.13 41 n-dodecyl [00133] [00134] [00135] 1.13 42 n-hexyl [00136] [00137] [00138] 1.13 43 n-hexyl [00139] [00140] [00141] 1.14 44 n-hexyl [00142] [00143] [00144] 1.14 45 n-hexyl [00145] [00146] [00147] 1.14 46 n-hexyl [00148] [00149] [00150] 1.14 47 n-hexyl [00151] [00152] [00153] 1.14 48 n-hexyl [00154] [00155] [00156] 1.15 49 n-butyl [00157] [00158] [00159] 1.15 50 n-hexyl [00160] [00161] [00162] 1.15 51 hexanol [00163] [00164] [00165] 1.15 52 n-hexyl [00166] [00167] [00168] 1.15 53 n-hexyl [00169] [00170] [00171] 1.16 54 n-hexyl [00172] [00173] [00174] 1.16 55 n-hexyl [00175] [00176] [00177] 1.16 56 n-hexyl [00178] [00179] [00180] 1.17 57 n-hexyl [00181] [00182] [00183] 1.17 58 n-hexyl [00184] [00185] [00186] 1.18 59 n-hexyl [00187] [00188] [00189] 1.18 60 n-hexyl [00190] [00191] [00192] 1.20 61 n-hexyl [00193] [00194] [00195] 1.20 62 n-hexyl [00196] [00197] [00198] 1.21 63 n-hexyl [00199] [00200] [00201] 1.24 64 cyclohexyl [00202] [00203] [00204] 1.24 65 n-hexyl [00205] [00206] [00207] 1.25 66 n-hexyl [00208] [00209] [00210] 1.26 67 n-hexyl [00211] [00212] [00213] 1.26 68 isopropyl [00214] [00215] [00216] 1.27 69 n-hexyl [00217] [00218] [00219] 1.28 70 n-hexyl [00220] [00221] [00222] 1.28 71 n-hexyl [00223] [00224] [00225] 1.28 72 n-hexyl [00226] [00227] [00228] 1.29 73 n-hexyl [00229] [00230] [00231] 1.29 74 n-hexyl [00232] [00233] [00234] 1.29 75 n-hexyl [00235] [00236] [00237] 1.31

TABLE-US-00002 TABLE 1a Oxidation potentials of various triarylalkylborate anions calculated according to formula (III), where the specified radicals refer to formula (III) as described herein and the oxidation potential is specified in [V] in comparison to the saturated calomel electrode in the solvent acetonitrile. E.sub.ox Example A-R.sup.100 R.sup.101 R.sup.102 R.sup.103 (calculated) 1 A: methylene, Para position: 4- Para position: 4- Para position: 4- 1.01 R.sup.100: n-pentyl = trifluoromethylphenyl trifluoromethylphenyl trifluoromethylphenyl A-R.sup.100: n-hexyl 2 A: methylene, Meta position: 2- Meta position: 2- Meta position: 2- 1.01 R.sup.100: n-pentyl = trifluoromethylphenyl trifluoromethylphenyl trifluoromethylphenyl A-R.sup.100: n-hexyl 3 A: methylene, Para position: methyl Para position: methyl, Para position: methyl, 1.02 R.sup.100: n-pentyl = meta position: meta position: A-R.sup.100: n-hexyl chlorine chlorine 4 A: methylene, hydrogen hydrogen Para position: ethynyl 1.02 R.sup.100: n-pentyl = A-R.sup.100: n-hexyl 5 A: methylene, hydrogen hydrogen Para position: iodine 1.02 R.sup.100: n-pentyl = A-R.sup.100: n-hexyl 6 A: methylene, Para position: 2- Para position: 2- Para position: 2- 1.02 R.sup.100: n-pentyl = trifluoromethylphenyl trifluoromethylphenyl trifluoromethylphenyl A-R.sup.100: n-hexyl 7 A: methylene, Para position: 3- Para position: 3- Para position: 3- 1.02 R.sup.100: n-pentyl = cyanophenyl cyanophenyl cyanophenyl A-R.sup.100: n-hexyl 8 A: methylene, Para position: methyl Para position: Para position: 1.03 R.sup.100: n-pentyl = chlorine chlorine A-R.sup.100: n-hexyl 9 A: methylene, hydrogen hydrogen Para position: 1.03 R.sup.100: n-pentyl = methylthiyl A-R.sup.100: n-hexyl 10 A: methylene, Meta position: methyl Meta position: methyl Meta position: 1.03 R.sup.100: n-pentyl = chlorine A-R.sup.100: n-hexyl 11 A: methylene, Para position: methyl, Para position: methyl, Para position: methyl, 1.03 R.sup.100: pentyl meta position: meta position: meta position: closed to form chlorine chlorine chlorine ring = A-R.sup.100: cyclohexyl 12 A: methylene, hydrogen hydrogen Para position: methyl, 1.04 R.sup.100: n-pentyl = meta position: A-R.sup.100: n-hexyl chlorine 13 A: methylene, hydrogen hydrogen Para position: 1.04 R.sup.100: n-pentyl = difluoromethyl A-R.sup.100: n-hexyl 14 A: methylene, Para position: 4- Para position: 4- Para position: 4- 1.05 R.sup.100: n-pentyl = cyanophenyl cyanophenyl cyanophenyl A-R.sup.100: n-hexyl 15 A: methylene, hydrogen hydrogen Para position: 1.06 R.sup.100: n-pentyl = fluorine A-R.sup.100: n-hexyl 16 A: methylene, hydrogen hydrogen Meta position: 1.06 R.sup.100: n-pentyl = chlorine A-R.sup.100: n-hexyl 17 A: methylene, hydrogen hydrogen Para position: 1.06 R.sup.100: n-pentyl = bromine A-R.sup.100: n-hexyl 18 A: methylene, hydrogen hydrogen Para position: 1.07 R.sup.100: n-pentyl = acetoxyphenyl A-R.sup.100: n-hexyl 19 A: methylene, Para position: methyl Meta position: Meta position: 1.07 R.sup.100: n-pentyl = fluorine fluorine A-R.sup.100: n-hexyl 20 A: methylene, hydrogen hydrogen Para position: 1.07 R.sup.100: n-pentyl = dichloromethyl A-R.sup.100: n-hexyl 21 A: methylene, hydrogen Para position: Para position: 1.07 R.sup.100: n-pentyl = fluorine fluorine A-R.sup.100: n-hexyl 22 A: methylene, Para position: thiyl Para position: thiyl Para position: thiyl 1.07 R.sup.100: n-pentyl = A-R.sup.100: n-hexyl 23 A: methylene, hydrogen hydrogen Para position: 1.08 R.sup.100: n-pentyl = chlorine A-R.sup.100: n-hexyl 24 A: methylene, hydrogen hydrogen Ortho position: 1.08 R.sup.100: n-pentyl = chlorine A-R.sup.100: n-hexyl 25 A: methylene, hydrogen hydrogen Para position: 1.08 R.sup.100: n-pentyl = trifluoromethoxy A-R.sup.100: n-hexyl 26 A: methylene, hydrogen hydrogen Para position: 1.08 R.sup.100: n-pentyl = trifluoromethyl A-R.sup.100: n-hexyl 27 A: methylene, Meta position: 3- Meta position: 3- Meta position: 3- 1.08 R.sup.100: n-pentyl = trifluoromethylphenyl trifluoromethylphenyl trifluoromethylphenyl A-R.sup.100: n-hexyl 28 A: methylene, hydrogen hydrogen Para position: 1.09 R.sup.100: n-pentyl = A-R.sup.100: n-hexyl 29 A: methylene, Para position: methyl Meta position: Meta position: 1.09 R.sup.100: n-pentyl = chlorine chlorine A-R.sup.100: n-hexyl 30 A: methylene, hydrogen hydrogen Ortho position: 1.09 R.sup.100: n-pentyl = fluorine A-R.sup.100: n-hexyl 31 A: methylene, hydrogen Para position: Para position: 1.09 R.sup.100: n-pentyl = methylthiyl methylthiyl A-R.sup.100: n-hexyl 32 A: methylene, Para position: Para position: Para position: 1.09 R.sup.100: n-pentyl = chlorine fluorine fluorine A-R.sup.100: n-hexyl 34 A: methylene, Para position: methyl Para position: Para position: 1.10 R.sup.100: n-pentyl = trifluoromethyl trifluoromethyl A-R.sup.100: n-hexyl 35 A: methylene, Para position: iodine Para position: iodine Para position: iodine 1.10 R.sup.100: n-pentyl = A-R.sup.100: n-hexyl 33 A: methylene, Para position: methyl, Para position: Para position: 1.11 R.sup.100: n-pentyl = meta position: chlorine chlorine A-R.sup.100: n-hexyl chlorine 36 A: methylene, hydrogen hydrogen Para position: 1.11 R.sup.100: n-pentyl = trifluoromethylthiyl A-R.sup.100: n-hexyl 37 A: methylene, hydrogen hydrogen Meta position: 1.11 R.sup.100: n-pentyl = trifluoromethyl A-R.sup.100: n-hexyl 38 A: methylene, Para position: methyl, Para position: methyl, Para position: methyl, 1.11 R.sup.100: 2- meta position: meta position: meta position: phenylethyl chlorine chlorine chlorine 39 A: methylene, hydrogen hydrogen Para position: 1.12 R.sup.100: n-pentyl = trichloromethyl A-R.sup.100: n-hexyl 40 A: methylene, Para position: Para position: Para position: 1.13 R.sup.100: n-pentyl = fluorine fluorine fluorine A-R.sup.100: n-hexyl 41 A: methylene, Para position: Para position: Para position: 1.13 R.sup.100: n-undecyl = fluorine fluorine fluorine A-R.sup.100: n-dodecyl 42 A: methylene, Meta position: 2- Meta position: 2- Meta position: 2- 1.13 R.sup.100: n-pentyl = cyanophenyl cyanophenyl cyanophenyl A-R.sup.100: n-hexyl 43 A: methylene, hydrogen hydrogen Meta position: 1.14 R.sup.100: n-pentyl = fluorine A-R.sup.100: n-hexyl 44 A: methylene, hydrogen Meta position: acetyl Meta position: acetyl 1.14 R.sup.100: n-pentyl = A-R.sup.100: n-hexyl 45 A: methylene, Meta position: 4- Meta position: 4- Meta position: 4- 1.14 R.sup.100: n-pentyl = trifluoromethylphenyl trifluoromethylphenyl trifluoromethylphenyl A-R.sup.100: n-hexyl 46 A: methylene, Meta position: 4- Meta position: 4- Meta position: 4- 1.14 R.sup.100: n-pentyl = cyanophenyl cyanophenyl cyanophenyl A-R.sup.100: n-hexyl 47 A: methylene, hydrogen hydrogen Meta position: 1.14 R.sup.100: n-pentyl = trifluoromethoxy A-R.sup.100: n-hexyl 48 A: methylene, Para position: methyl, Para position: methyl, Para position: methyl, 1.15 R.sup.100: n-pentyl = meta position: meta position: meta position: A-R.sup.100: n-hexyl chlorine chlorine chlorine 49 A: methylene, Para position: methyl, Para position: methyl, Para position: methyl, 1.15 R.sup.100: n-propyl = meta position: meta position: meta position: A-R.sup.100: n-butyl chlorine chlorine chlorine 50 A: methylene, hydrogen hydrogen Meta position: 1.15 R.sup.100: n-pentyl = trifluoromethylthiyl A-R.sup.100: n-hexyl 51 A: methylene, Para position: methyl, Para position: methyl, Para position: methyl, 1.15 R.sup.100: n-pentanol = meta position: meta position: meta position: A-R.sup.100: n-hexanol chlorine chlorine chlorine 52 A: methylene, Para position: Para position: Para position: methyl, 1.15 R.sup.100: n-pentyl = fluorine fluorine meta position: A-R.sup.100: n-hexyl chlorine 53 A: methylene, Para position: methyl, Para position: Para position: 1.16 R.sup.100: n-pentyl = meta position: fluorine fluorine A-R.sup.100: n-hexyl chlorine 54 A: methylene, hydrogen hydrogen Meta position: 1.16 R.sup.100: n-pentyl = trichloromethyl A-R.sup.100: n-hexyl 55 A: methylene, Meta position: 3- Meta position: 3- Meta position: 3- 1.16 R.sup.100: n-pentyl = cyanophenyl cyanophenyl cyanophenyl A-R.sup.100: n-hexyl 56 A: methylene, Para position: Para position: Para position: 1.17 R.sup.100: n-pentyl = chlorine chlorine chlorine A-R.sup.100: n-hexyl 57 A: methylene, Para position: methyl Para position: methyl Meta position: 1.17 R.sup.100: n-pentyl = trifluoromethyl A-R.sup.100: n-hexyl 58 A: methylene, Para position: Para position: Para position: 1.18 R.sup.100: n-pentyl = chlorine chlorine fluorine A-R.sup.100: n-hexyl 59 A: methylene, Ortho position: Ortho position: Ortho position: 1.18 R.sup.100: n-pentyl = chlorine chlorine chlorine A-R.sup.100: n-hexyl 60 A: methylene, Para position: methyl, Para position: methyl, Para position: 1.20 R.sup.100: n-pentyl = meta position: meta position: trifluoromethyl A-R.sup.100: n-hexyl chlorine chlorine 61 A: methylene, Meta position: Meta position: Para position: methyl, 1.20 R.sup.100: n-pentyl = chlorine chlorine meta position: A-R.sup.100: n-hexyl chlorine 62 A: methylene, Meta position: Meta position: Para position: methyl, 1.21 R.sup.100: n-pentyl = fluorine fluorine meta position: A-R.sup.100: n-hexyl chlorine 63 A: methylene, Para position: Para position: hydrogen 1.24 R.sup.100: n-pentyl = trichloromethyl trichloromethyl A-R.sup.100: n-hexyl 64 A: methylene, Meta position: Meta position: Meta position: 1.24 R.sup.100: pentyl chlorine chlorine chlorine closed to form ring = A-R.sup.100: cyclohexyl 65 A: methylene, Para position: Para position: hydrogen 1.25 R.sup.100: n-pentyl = trifluoromethyl trifluoromethyl A-R.sup.100: n-hexyl 66 A: methylene, Meta position: Meta position: hydrogen 1.26 R.sup.100: n-pentyl = trifluoromethoxy trifluoromethoxy A-R.sup.100: n-hexyl 67 A: methylene, Ortho position: Ortho position: Ortho position: 1.26 R.sup.100: n-pentyl = fluorine fluorine fluorine A-R.sup.100: n-hexyl 68 A: methine, Meta position: Meta position: Meta position: 1.27 R.sup.100; dimethyl chlorine chlorine chlorine 69 A: methylene, Meta position: Meta position: Meta position: 1.28 R.sup.100: n-pentyl = fluorine fluorine fluorine A-R.sup.100: n-hexyl 70 A: methylene, Para position: Para position: Para position: methyl, 1.28 R.sup.100: n-pentyl = trifluoromethyl trifluoromethyl meta position: A-R.sup.100: n-hexyl chlorine 71 A: methylene, Meta position: Meta position: hydrogen 1.28 R.sup.100: n-pentyl = trifluoromethyl trifluoromethyl A-R.sup.100: n-hexyl 72 A: methylene, Meta position: Meta position: Para position: 1.29 R.sup.100: n-pentyl = trifluoromethyl trifluoromethyl fluorine A-R.sup.100: n-hexyl 73 A: methylene, Meta position: Meta position: hydrogen 1.29 R.sup.100: n-pentyl = trichloromethyl trichloromethyl A-R.sup.100: n-hexyl 74 A: methylene, Meta position: Meta position: Meta position: 1.29 R.sup.100: n-pentyl = fluorine fluorine chlorine A-R.sup.100: n-hexyl 75 A: methylene, Meta position: hydrogen hydrogen 1.31 R.sup.100: n-pentyl = trifluoromethyl A-R.sup.100: n-hexyl
Evaluation of the Thermal Stability of the Photopolymer Films with Coinitiators According to the Invention:

[0225] The requirements for the photopolymer films produced here are a low performance loss of the photoactivity after a temperature conditioning step, i.e. that both the transmission of the photopolymer after the temperature conditioning step must not increase critically and the diffraction efficiency after the hologram exposure must not decrease critically.

[0226] First, two samples were prepared in the same way for each example. The preparation comprises first the removal of the laminating film of the photopolymer layer structure and subsequently the lamination of the resulting unprotected side of the photopolymer onto a glass sheet, so that each time a glass-photopolymer-substrate film layer structure is present. From one of these samples, later referred to as room temperature sample (RT), a transmission spectrum (T.sub.1,RT) was recorded directly without temperature conditioning. The second sample, later referred to as temperature conditioning sample (Temp), was temperature-conditioned in a drying oven for 10 min at 110 C. After the temperature conditioning step, a transmission spectrum (T.sub.1,Temp) was also recorded from the sample. Consequently, a test hologram was written into the photopolymer layer of both samples with an 850 nm laser using a laser set-up as described above. The quality of this hologram was assessed by the refractive index difference between exposed and unexposed surfaces (n) in the sample, derived from the diffraction efficiency read out. The thermal stability of an NIR-light-sensitive photopolymer was assessed on the basis of two criteria that absolutely must be fulfilled. The two fulfillment criteria are described in detail subsequently: [0227] 1. Thermal stability evaluated according to transmission loss TS(T): The ratio of the transmission at the absorption maximum of the dye used (here 830 nm) after the temperature conditioning step of the Temp sample, T.sub.1,Temp,830, to the transmission of the RT sample at the same wavelength, T.sub.1,RT,830, must be greater than 50%. The transmission values here must be corrected for the background absorption caused by turbidity or the like (the transmission at 1000 nm is used here as reference value) (T.sub.2,Temp,1000):

[00013]$\begin{array}{cc}TS\left(T\right)=\frac{T_{1,\mathrm{Temp},830}-T_{2,\mathrm{Temp},1000}}{T_{1,\mathrm{RT},830}-T_{2,\mathrm{Temp},1000}}>50\%& \left(21\right)\end{array}$ [0228] 2. Thermal stability evaluated according to n: TS(n): The refractive index difference n of the Temp sample must be greater than 0.015:

[00014]$\begin{array}{cc}TS\left(n\right)=n_{\mathrm{Temp}}>0.015& \left(22\right)\end{array}$

[0229] The following transmission and n values of some examples according to the invention and not according to the invention were determined:

TABLE-US-00003 TABLE 2 Measured transmission and n values of the examples according to the invention and not according to the invention, and the evaluations calculated therefrom. T.sub.1, RT, 830: Transmission of RT sample at 830 nm; T.sub.1, Temp, 830: Transmission of Temp sample at 830 nm; T.sub.2, Temp, 1000: Background transmission determined at 1000 nm; TS(T): Evaluation of thermal stability according to transmission loss; TS(n): Evaluation of thermal stability according to n. T.sub.1, RT, 830 T.sub.1, Temp, 830 T.sub.2, Temp, 830 T.sub.2, Temp, 1000 TS(T) Ex. E.sub.ox (V)* (%) (%) (%) (%) (%) TS(n) NEB1 1 48 80 92 93 28% 0 3a 1.02 35 39 92 92 94 0.0316 3b 1.02 41 47 92 92 90 0.0308 3c 1.02 41 47 92 93 88 0.0305 3d 1.02 46 51 92 92 89 0.0255 8 1.03 42 48 91 92 87 0.0266 11 1.03 38 39 91 92 99 0.0326 12 1.04 48 62 92 92 69 0.0235 15 1.06 13 31 91 92 78 0.0183 38 1.11 39 41 92 92 96 0.0224 41 1.13 48 54 92 93 87 0.0272 48 1.15 42 42 92 92 99 0.0312 49 1.15 40 41 92 92 98 0.0363 56 1.17 41 40 92 92 100 0.0311 NEB2 1.32 37 38 92 92 99 0.0147 NEB3 1.45 36 36 92 92 100 0 *vs. SCE in acetonitrile; calculated; based on the triarylalkylborate used.

[0230] The results clearly show that the required thermal stability of a photopolymer is achieved with the triarylalkylborate salts according to the invention. A photopolymer can therefore only be assumed to be sufficiently thermally stable if the calculated oxidation potential of the borate salt used is greater than 1.00 V and less than 1.32 V vs. SCE in acetonitrile. The use of all borates listed in table 1 as coinitiators in photopolymers therefore leads to thermally stable photopolymers in accordance with the objective of this invention. It is also remarkable that the thermal stability of the photopolymer does not depend on the countercation of the borate salt used, as a comparison of examples 3a to 3d shows. A variation of the alkyl radical of the triarylalkylborate salt is also possible without loss of the thermal stability of the photopolymer, as emphasized by examples 11, 38, 48 and 49.

[0231] The examples NEB1, NEB2 and NEB3 not according to the invention fail in at least one required property and are thus unsuitable for providing a photopolymer composition having the required properties.