EP4483367A1 - Triarylalkyl borate salts as coinitiators in nir photopolymer compositions - Google Patents

Abstract

The invention relates to photopolymer compositions 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 auxiliary agents and/or admixtures, wherein 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 (A) which is ascertained according to the formula (1) indicated below by means of a quantum mechanical computation of the Gibbs free energy of the base state and the oxidized state of the triarylalkyl borate at 298 K after a successful geometry optimization, consisting of a compliant energy minimization by means of the AMI force field followed by an ab initio compliant energy computation on the basis of the previously ascertained molecular geometry coordinates, in the solvent acetonitrile using a solvent field correction according to the PCM method, ranging from 1.01 V to 1.31 V with respect to the calomel electrode (SCE) saturated in acetonitrile (1).

Description

Triarylalkyl borate salts as coinitiators in NIR photopolymer compositions

The invention relates to photopolymer compositions using selected triarylalkylborate salts as coinitiators, photopolymer compositions with a selected oxidation potential, and holographic media and holograms produced therefrom, and also to a method for producing a holographic medium using the special photopolymer composition including the special coinitiators and a holographic Medium obtainable using the photopolymer composition according to the invention. Furthermore, the invention relates to a layer structure comprising a holographic medium according to the invention and likewise special triarylalkyl borate salts suitable as coinitiators. Furthermore, a method for calculating the oxidation potential against the saturated calomel electrode in acetonitrile of the special coinitiators is presented. Furthermore, a process for preparing the specific coinitiators and the coinitiators obtainable by this process are described.

Photopolymer compositions incorporating general forms of triarylalkyl borate salts are known in the art. For example, WO 2008/125229 describes a photopolymer composition and a photopolymer obtainable therefrom, which comprise polyurethane matrix polymers, an acrylate-based writing monomer and photoinitiators comprising a coinitiator and a dye. When using photopolymers, the refractive index modulation Δn generated by the holographic exposure plays the decisive role. During holographic exposure, the interference field from the signal and reference light beam (in the simplest case, that of two plane waves) is mapped into a refractive index grating by the local photopolymerization of writing monomers such as high-index acrylates at locations of high intensity in the interference field. The refractive index grating in the photopolymer (the hologram) contains all the information of the signal light beam. The signal can be reconstructed by illuminating the hologram only with the reference light beam. The strength of the signal reconstructed in this way in relation to the strength of the incident reference light is called diffraction efficiency, hereinafter DE, for diffraction efficiency.

In the simplest case of a hologram, which is created from the superposition of two plane waves, the DE results from the quotient of the intensity of the light diffracted during the reconstruction and the sum of the intensities from the non-diffracted and diffracted light. The higher the DE, the more efficient a hologram is in terms of the amount of light from the reference light necessary to make the signal visible at a given brightness.

In order to be able to achieve the highest possible Δn and the highest possible DE for holograms, the matrix polymers and the writing monomers of a photopolymer composition should always be selected in such a way that their refractive indices differ as much as possible. One possibility for realization is matrix polymers with the lowest possible and To use writing monomers with the highest possible refractive index. Suitable matrix polymers with a low refractive index are, for example, polyurethanes obtainable by reacting a polyol component with a polyisocyanate component.

In addition to high DE and Δn values, it is also of great importance for holographic media made from photopolymer compositions that the matrix polymers in the finished medium are highly crosslinked. If the degree of crosslinking is too low, the medium does not have sufficient stability. This can result in the quality of holograms written in the media degrading significantly and changing over time, which is undesirable. In the worst case, the holograms can even be destroyed afterwards.

Furthermore, it is of great importance, particularly for the large-scale industrial use of holographic media made from photopolymer compositions, that the photopolymer films which contain the photopolymer composition have a large processing window and can be exposed without loss of index modulation. In this case, the choice of a suitable photoinitiator is particularly important for the properties of the photopolymer.

Very suitable photoinitiators for photopolymer films of the type mentioned can consist of type II photoinitiators. In these type II photoinitiators, triaryl alkyl borate salts as coinitiators can be combined with suitable sensitizers, such as cationic, anionic, or neutral dyes, as a photoinitiating system (PIS) such that visible or near-infrared light can trigger radical photopolymerization of suitable monomers can. The production of such PIS is widely described in the prior art and selected tetraalkylammonium triarylalkyl borates and dyes for the near infrared (NIR) range are commercially available. Furthermore, such PIS have already been used in photopolymers and holographic media and their advantages have been described. For example, in EP 0438123 cationic NIR dyes such as the NIR dye of formula (1) described, which together with the triphenylbutylborate anion a PIS for photocurable materials can be used. This application also shows the tri(p-anisyl)butylborate anion or the tri(l-naphthyl)butylborate anion as suitable coinitiators for PIS with cationic NIR dyes. Furthermore, from US 6022664, wherein the production of thermal describes activatable photopolymers, it is known that recording materials containing a PIS consisting of an NIR dye of the formula (1) and certain triarylalkylborate salts cure almost completely after 5 seconds at a temperature of 120.degree. However, with all of these PISs, such as those dye-coinitiator combinations and photopolymer compositions described in EP 0438123 containing an NIR dye and triarylalkyl borate salts, no attention was paid to the thermal stability of the formulation in the unexposed state. In fact, all the formulations disclosed in EP 0438123 do not have sufficient thermal stability in the unexposed state. This means that under a certain thermal load, such as 10 min storage at 110 °C, which may be necessary to produce holographic optical products, an undesirable side reaction occurs in the photopolymer film, which significantly reduces or reduces the conversion of the photoreaction that starts during exposure completely prevented and the quality of the holograms to be inscribed deteriorates significantly or the creation of holograms is made impossible. Consequently, previous photopolymer films cannot be thermally treated to the necessary extent before exposure. However, this is disadvantageous for certain applications which require handling of the unexposed photopolymer film at elevated temperature.

It was therefore an object of the invention to provide photopolymer compositions which make it possible to handle unexposed photopolymer films under increased thermal stress without their bleachability or sensitivity being adversely affected during the exposure process. Furthermore, it was an object to provide photopolymer compositions which increase the thermal stability of photopolymer films in the unexposed state. In this case, other properties such as bleachability or sensitivity should preferably not be adversely affected during the exposure process. This technical problem has been solved by the subject-matter of claim 1 and its dependent claims.

A first object of the invention is 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 or additives, where the at least one photoinitiator system c) consists of at least one dye and at least one coinitiator, where the dye has a structure of the formula (II). wherein

R ²⁰⁵ is hydrogen, halogen, C ₁ - to C ₄ -alkyl, C ₁ - to C ₄ -alkoxy or NR ²¹⁰ R ²¹¹ ,

R ²⁰⁶ is hydrogen, halogen, C ₁ - to C ₄ -alkyl, C ₁ - to C ₄ -alkoxy or NR ²¹² R ²¹³ ,

R ²⁰¹ to R ²⁰⁴ and R ²¹⁰ to R ²¹³ are each independently hydrogen, C ₁ - to C ₁₆ - alkyl, C ₄ - to C ₇ -cycloalkyl, C ₇ - to C ₁₆ -aralkyl, C ₆ - to C ₁₀ -Aryl or a heterocyclic radical,

NR ²⁰¹ R ²⁰² , NR ²⁰³ R ²⁰⁴ , NR ²¹⁰ R ²¹¹ and NR ²¹² R ²¹³ independently represent a five- or six-membered saturated ring attached via N, which may additionally contain an N or O and/or be substituted by nonionic radicals can be,

R ²⁰⁷ to R ²⁰⁹ independently of one another are hydrogen, C ₁ - to C ₁₆ -alkyl, C ₄ - to C ₇ -cycloalkyl, C ₇ - to C ₁₆ -aralkyl, C ₆ - to C ₁₀ -aryl, halogen or Are cyano, the two optional bridging groups X ¹ and X ² are independently SiR ²¹⁴ R ²¹⁵ , CR ²¹⁶ R ²¹⁷ or O and

R ²¹⁴ to R ²¹⁷ independently represent hydrogen or C ₁ - to C ₄ -alkyl and

An for an anion selected from halide, cyanide, nitrate, azide, perchlorate, hexafluorophosphate, hexafluoroantimonate, any substituted phosphate, any substituted phosphonate, any substituted sulfonimide, such as bis(trifluoromethyl)sulfonimide, any substituted organic borate, such as tetrafluoroborate, tetraarylborate, triarylalkylborate or cyanotriarylborate, optionally substituted alkyl or alkenyl sulfate, optionally substituted mono- or di-sulfonate, such as methylsulfonate, p-toluenesulfonate, trifluoromethylsulfonate, or sulfusuccinate, or an optionally substituted organic mono- or di-carboxylate, and the at least one coinitiator has a calculated oxidation potential ^t , 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 triaryl alkylborate after geometry optimization, consisting of Conformer energy minimization using the AMI force field followed by ab initio conformer energy calculation based on the previously determined molecular geometry coordinates, in the solvent acetonitrile with solvent field correction according to the PCM method, in the range from 1.01 V to 1.31 V versus the saturated calorimetric (1) measuring electrode (SCE) in acetonitrile

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

It is preferred that the matrix polymers a) are polyurethanes, it being possible for the polyurethanes to be obtainable in particular by reacting at least one polyisocyanate component a1) with at least one isocyanate-reactive component all).

The polyisocyanate component a1) preferably comprises at least one organic compound having at least two NCO groups. These organic compounds can in particular be monomeric di- and triisocyanates, polyisocyanates and/or NCO-functional prepolymers. The polyisocyanate component a1) can also contain or consist of mixtures of monomeric di- and triisocyanates, polyisocyanates and/or NCO-functional prepolymers.

All compounds well known per se to the person skilled in the art or mixtures thereof can be used as monomeric di- and triisocyanates. These compounds can have aromatic, araliphatic, aliphatic or cycloaliphatic structures. In minor amounts, the monomeric di- and triisocyanates can also include monoisocyanates, i.e. organic compounds with an NCO group.

Examples of suitable monomeric di- and triisocyanates are 1,4-butane diisocyanate, 1,5-pentane diisocyanate, 1,6-hexane diisocyanate (hexamethylene diisocyanate, HDI), 2,2,4-trimethylhexamethylene diisocyanate and/or 2,4, 4-trimethylhexamethylene diisocyanate (TMDI), isophorone diisocyanate (IPDI), l,8-diisocyanato-4-(isocyanatomethyl)octane, bis-(4,4'-isocyanatocyclohexyl)methane and/or bis-(2',4-isocyanatocyclohexyl) Methane and / or mixtures of any isomer content, 1, 4-cyclohexane diisocyanate, the isomeric bis (isocyanatomethyl) cyclohexane, 2,4- and / or 2,6-diisocyanato-l-methylcyclohexane (hexahydro-2,4- and / or 2,6-tolylene diisocyanate, H ₆ - TDI), 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI), 1,5-naphthylene diisocyanate (ND1), 2,4 '- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1,3-bis(iso- cyanatomethyl)benzene (XDI) and/or the analogous 1,4-isomer or any mixtures of the aforementioned compounds.

Suitable polyisocyanates are compounds with urethane, urea, carbodiimide, acylurea, amide, isocyanurate, allophanate, biuret, oxadiazinetrione, uretdione and/or iminooxadiazine dione structures, which are composed of the aforementioned di- or Triisocyanates are available.

The polyisocyanates are particularly preferably oligomerized aliphatic and/or cycloaliphatic di- or triisocyanates, it being possible in particular to use the above aliphatic and/or cycloaliphatic di- or triisocyanates.

Very particular preference is given to polyisocyanates with isocyanurate, uretdione and/or iminooxadiazinedione structures and biurets based on HD1 or mixtures thereof.

Suitable prepolymers contain urethane and/or urea groups and, if appropriate, other structures resulting from modification of NCO groups, as mentioned above. Prepolymers of this type are obtainable, for example, by reacting the abovementioned monomeric di- and triisocyanates and/or polyisocyanates all) with isocyanate-reactive compounds all1).

Alcohols, amino or mercapto compounds, preferably alcohols, can be used as isocyanate-reactive compounds alll). In particular, these can be polyols. Polyester, polyether, polycarbonate, poly(meth)acrylate and/or polyurethane polyols can very particularly preferably be used as the isocyanate-reactive compound alll).

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 dicarboxylic or polycarboxylic acids or their anhydrides with polyhydric alcohols having an OH functionality of ≧2. Examples of suitable di- or polycarboxylic acids are polybasic carboxylic acids such as succinic, adipic, suberic, sebacic, decanedicarboxylic, phthalic, terephthalic, isophthalic, tetrahydrophthalic or trimellitic acid and acid anhydrides such as phthalic, trimellitic or succinic anhydride or any mixtures thereof with one another. The polyester polyols can also be based on natural raw materials such as castor oil. It is also possible for the polyester polyols to be based on homopolymers or copolymers of lactones, which are preferably formed by addition of lactones or lactone mixtures such as butyrolactone, ε-caprolactone and/or methyl-ε-caprolactone onto hydroxy-functional compounds such as polyhydric alcohols with an OH functionality ≥ 2 can be obtained, for example, of the type mentioned below.

Examples of suitable alcohols are all polyhydric alcohols such as the C ₂ -C ₁₂ diols, the isomeric cyclohexanediols, glycerol or any mixtures thereof with one another.

Suitable polycarbonate polyols can be obtained in a manner known per se by reacting organic carbonates or phosgene with diols or diol mixtures. Suitable organic carbonates are dimethyl, diethyl and diphenyl carbonate.

Suitable diols or mixtures include the polyhydric alcohols mentioned per se in the context of the polyester segments with an OH functionality ≧2, preferably 1,4-butanediol, 1,6-hexanediol and/or 3-methylpentanediol. Polyester polyols can also be converted into polycarbonate polyols.

Suitable polyether polyols are, if appropriate, block-wise polyaddition products of cyclic ethers onto OH- or NH-functional starter molecules.

Examples of suitable cyclic ethers are styrene oxide, ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, epichlorohydrin and any mixtures thereof.

The polyhydric alcohols mentioned per se in the context of the polyester polyols with an OH functionality ≧2 and primary or secondary amines and amino alcohols can be used as starters.

Preferred polyether polyols are those of the aforementioned type based exclusively on propylene oxide or random or block copolymers based on propylene oxide with other 1-alkylene oxides. Propylene oxide homopolymers and random or block copolymers which have oxyethylene, oxypropylene and/or oxybutylene units are particularly preferred, with the proportion of oxypropylene units based on the total amount of all oxyethylene, oxypropylene and oxybutylene units being at least 20% by weight at least 45% by weight. In this context, oxypropylene and oxybutylene include all the respective linear and branched C ₃ and C ₄ isomers.

In addition, low molecular weight, i.e. with molecular weights ≦500 g/mol, short-chain, i.e. containing 2 to 20 carbon atoms, aliphatic, araliphatic or cycloaliphatic di-, tri- or polyfunctional alcohols are also suitable as components of the polyol component alll) as polyfunctional, isocyanate-reactive compounds.

This can, for example, in addition to the above-mentioned compounds neopentyl glycol,

2-ethyl-2-butylpropanediol, trimethylpentanediol, position isomeric diethyloctanediols, cyclohexanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 1,2- and 1,4-cyclohexanediol, hydrogenated bisphenol A, 2,2- Bis(4-hydroxycyclohexyl)propane or 2,2-dimethyl-3-hydroxypropionic acid, 2,2-dimethyl

be 3-hydroxypropyl ester. Examples of suitable triols are trimethylolethane, trimethylolpropane or glycerol. Suitable higher-functional alcohols are di-(trimethylolpropane), pentaerythritol, dipentaerythritol or sorbitol.

It is particularly preferred if the polyol component is a difunctional polyether, polyester or a polyether-polyester-block-copolyester or a polyether-polyester-block copolymer with primary OH functions. It is also possible to use alll) amines as isocyanate-reactive compounds. Examples of suitable amines are ethylenediamine, propylenediamine, diaminocyclohexane, 4,4'-dicyclohexylmethanediamine, isophoronediamine (IPDA), difunctional polyamines such as Jeffamine®, amine-terminated polymers, in particular with number-average molar masses ≦10,000 g/mol. Mixtures of the aforementioned amines can also be used.

It is also possible to use alll) amino alcohols as isocyanate-reactive compounds. Examples of suitable amino alcohols are the isomeric aminoethanols, the isomeric aminopropanols, the isomeric aminobutanols and the isomeric aminohexanoie or any mixtures thereof.

All of the aforementioned isocyanate-reactive compounds alll) can be mixed with one another as desired.

It is also preferred if the isocyanate-reactive compounds alll) 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 from 1.5 to 6.0, particularly preferably from 1.8 to 4.0.

The prepolymers of the polyisocyanate component a1) can in particular have a residual content of free monomeric di- and triisocyanates of <1% by weight, particularly preferably <0.5% by weight and very particularly preferably <0.3% by weight.

It is optionally also possible for the polyisocyanate component a1) to contain all or part of an organic compound whose NCO groups have been reacted in whole or in part with blocking agents known from coating technology. Examples of blocking agents are alcohols, lactams, oximes, malonic esters, pyrazoles and amines, such as butanone oxime, diisopropylamine, diethyl malonate, acetoacetic ester, 3,5-dimethylpyrazole, s-caprolactam or mixtures thereof.

It is particularly preferred if the polyisocyanate component a1) comprises compounds with aliphatically bonded NCO groups, aliphatically bonded NCO groups being understood as meaning groups which are bonded to a primary carbon atom. The isocyanate-reactive component all) 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, hydroxy, amino or mercapto groups are considered to be preferred as isocyanate-reactive groups.

The isocyanate-reactive component can in particular comprise compounds which have on average at least 1.5 and preferably 2 to 3 isocyanate-reactive groups.

Suitable polyfunctional, isocyanate-reactive compounds of component all) are, for example, the compounds all1) described above. In a further preferred embodiment it is provided that the substance catalyzing the polyurethane formation comes from the group of Zmn-based organyls, or 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.

The writing monomer b) can be any writing monomer that one skilled in the art would select for the photopolymer composition according to the invention. The writing monomer b) preferably comprises or consists of at least one monofunctional and/or one multifunctional writing monomer. More preferably, the writing monomer b) can comprise or consist of at least one monofunctional and/or one multifunctional (meth)acrylate writing monomer. Very particularly preferably, the writing monomer can comprise or consist of at least one monofunctional and/or one multifunctional urethane (meth)acrylate.

Suitable acrylate writing monomers are, in particular, compounds of the general formula (IV) where m≥land m≤4 and R ⁵ is a linear, branched, cyclic or heterocyclic unsubstituted or optionally substituted with heteroatoms organic radical and / or R ⁶ is hydrogen, a linear, branched, cyclic or heterocyclic unsubstituted or counter is also an organic radical substituted with heteroatoms. R ⁶ is particularly preferably hydrogen or methyl and/or R ⁵ is a linear, branched, cyclic or heterocyclic organic radical which is unsubstituted or optionally also substituted with heteroatoms.

In the present case, esters of acrylic acid or methacrylic acid are referred to as acrylates or methacrylates. 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 analogues or N-carbazolyl acrylates.

In the present case, urethane acrylates are understood as meaning compounds having at least one acrylic acid 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.

Examples of isocyanate-functional compounds that can be used for this purpose are monoisocyanates and the monomeric diisocyanates, triisocyanates and/or polyisocyanates mentioned under a1). examples suitable monoisocyanates are phenyl isocyanate, the isomeric methylthiophenyl isocyanates. Di-, tri- or polyisocyanates are mentioned above, as well as triphenylmethane-4,4',4"-triisocyanate and tris(p-isocyanatophenyl)thiophosphate or their derivatives with urethane, urea, carbodiimide, acylurea, isocyanurate , allophanate, biuret, oxadiazinetrione, uretdione, iminooxadiazinedione structure and mixtures thereof. Aromatic di-, tri- or polyisocyanates are preferred.

Examples of hydroxy-functional acrylates or methacrylates for the production of urethane acrylates are compounds such as 2-hydroxyethyl (meth)acrylate, polyethylene oxide mono(meth)acrylates, polypropylene oxide mono(meth)acrylates, polyalkylene oxide mono(meth)acrylates, poly(s- 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. 2-Hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate and poly(ε-caprolactone) mono(meth)acrylate are preferred.

The known hydroxyl-containing epoxy (meth)acrylates with OH contents of 20 to 300 mg KOH/g or hydroxyl-containing polyurethane (meth)acrylates with OH contents of 20 to 300 mg KOH/g or acrylated polyacrylates can also be used with OH contents of 20 to 300 mg KOH/g and mixtures thereof with one another and mixtures with hydroxyl-containing unsaturated polyesters and mixtures with polyester (meth)acrylates or mixtures of hydroxyl-containing unsaturated polyesters with polyester (meth)acrylates.

Particularly preferred are urethane acrylates 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 substituted naphthols.

It is also possible for the writing monomer b) to contain other unsaturated compounds such as α,β-unsaturated carboxylic acid derivatives such as maleates, fumarates, maleimides, acrylamides, vinyl ethers, propenyl ethers, allyl ethers and dicyclopentadienyl units, and olefinically unsaturated compounds such as e.g. styrene, α-methyl styrene, vinyl toluene and / or olefins, comprises or consists of.

The at least one photoinitiator system c) can be any photoinitiator system that a person skilled in the art would select for the photopolymer composition according to the invention. Photoinitiators of Component c) are usually compounds which can be activated by actinic radiation and can trigger polymerization of the writing monomers. Photoinitiators can be divided into unimolecular (type 1) and bimolecular (type II) initiators. Furthermore, depending on their chemical nature, they are divided into photoinitiators for free-radical, anionic, cationic or mixed types of polymerization.

Type I photoinitiators (Norrish type 1) for radical photopolymerization generate free radicals by unimolecular bond cleavage upon irradiation. Examples of type 1 photoinitiators are triazines, oximes, benzoin ethers, benzil ketals, bisimidazoles, aroylphosphine oxides, sulfonium and iodonium salts.

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

Type II photoinitiators are preferably used.

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

Examples of suitable NIR chromophores which, together with a compound of the formula (III), form a type II photoinitiator are the cationic dyes described in EP 0438123.

Furthermore, pentamethine cyanine and heptamethine cyanine dyes, hemicyanine dyes, merocyanine dyes, oxonols and neutrocyanine dyes are understood and preferred as cationic NIR dyes. Such dyes are, for example, in H. Bemeth in Ullmann's Encyclopedia of Industrial Chemistry, Azine Dyes, Wiley-VCH Verlag, 2008, H. Bemeth 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, 2,000.

Pentamethine cyanine and heptamethine cyanine dyes are particularly preferred.

A most preferred cationic NIR dye is Karenz IR-T dye available from Showa Denko and having the following structural formula (V):

Preferred anions (an-) of the cationic NIR dyes are in particular C ₈ - to C ₂₅ -alkanesulfonate, preferably C ₁₃ - to C ₂₅ -alkanesulfonate, C ₃ - to C ₁₈ -perfluoroalkanesulfonate, C ₄ - to C ₁₈ - Perfluoroalkanesulfonate which carries at least 3 hydrogen atoms in the alkyl chain, C ₉ - to C ₂₅ -alkanoate, C ₉ - to C ₂₅ -alkenoate, C ₈ - to C ₂₅ -alkyl sulfate, preferably C ₁₃ - to C ₂₅ -alkyl sulfate, C ₈ to C ₂₅ alkenyl sulfate, preferably C ₁₃ to C ₂₅ alkenyl sulfate, C ₃ to C ₁₈ perfluoroalkyl sulfate, C ₄ to C ₁₈ perfluoroalkyl sulfate which carries at least 3 hydrogen atoms in the alkyl chain, polyether sulfates based to at least 4 equivalents of ethylene oxide and/or 4 equivalents of propylene oxide, bis-C ₄ to C ₂₅ alkyl, C ₅ to C ₇ cycloalkyl, C ₃ to C ₈ alkenyl or C ₇ to C ₁₁ Aralkyl sulfosuccinate, bis-C ₂ - to C ₁₀ -alkyl sulfosuccinate substituted by at least 8 fluorine atoms, C ₈ - to C ₂₅ - alkyl sulfoacetates, by at least one radical from the group halogen, C ₄ - to C ₂₅ -Alkyl, perfluoro-C ₁ - to C ₈ -alkyl and / or C ₁ - to C ₁₂ - alkoxycarbonyl substituted benzene sulfonate, optionally by nitro, cyano, hydroxy, C ₁ - to C ₂₅ -alkyl, C ₁ - to C _{C 12} -alkoxy, amino, C ₁ - to C ₁₂ - alkoxycarbonyl or chlorine-substituted naphthalene or biphenyl sulfonate, optionally substituted by nitro, cyano, hydroxy, C ₁ - to C ₂₅ -alkyl, C ₁ - to C ₁₂ -alkoxy, C Benzene, naphthalene or biphenyl disulfonate substituted by C ₁ - to C ₁₂ - alkoxycarbonyl or chlorine, benzoate substituted by dinitro, C ₆ - to C ₂₅ -alkyl, C ₄ - to C ₁₂ - alkoxycarbonyl, benzoyl, chlorobenzoyl or toluoyl, the anion of Naphthalene dicarboxylic acid, diphenyl ether disulfonate, sulfonated or sulfated, optionally at least monounsaturated C ₈ - to C _{25 -fatty} acid esters of aliphatic C ₁ - to C ₈ -alcohols or glycerol, bis (sulfo-C ₂ - to C ₆ -alkyl) -C ₃ - to C ₁₂ -alkanedicarboxylic acid esters, bis-(sulfo-C ₂ - to C ₆ -alkyl)-itaconic acid esters, (sulfo-C ₂ - to C ₆ -alkyl)-C ₆ - to C ₁₈ -alkanecarboxylic acid esters, ( Sulfo-C ₂ - to C ₆ -alkyl)-acrylic or methacrylic acid ester, triscatecho iphosphate optionally substituted by up to 12 halogen radicals, an anion from the group tetraphenyl borate, cyanotriphenyl borate, tetraphenoxy borate, C ₄ - to C ₁₂ -alkyl triphenyl borate whose phenyl or phenoxy radicals can be substituted by halogen, C ₁ - to C ₄ -alkyl and/or C ₁ - to C ₄ -alkoxy, C ₄ - to C ₁₂ -alkyl trinaphthylborate, tetra-C ₁ - to C ₂₀ -alkoxyborate, 7,8- or 7,9- dicarbanidoundecaborate(l-) or (2-), optionally substituted on the B and/or C atoms by one or two C ₁ - to C ₁₂ -Alkyl or phenyl groups are substituted, dodecahydrodicarbadodecaborate(2-) or BC ₁ - to C ₁₂ -alkyl-C-phenyl-dodecahydrodicarbadodecaborate(l-), where in the case of polyvalent anions such as naphthalene disulfonate An- represents an equivalent of this anions stands, and where the alkane and alkyl groups can be branched and/or can be substituted by halogen, cyano, methoxy, ethoxy, methoxycarbonyl or ethoxycarbonyl.

The anions described in WO 2012062655 are preferably used as anions.

It is also preferred if the anion An- of the dye has an AClogP in the range from 1 to 30, particularly preferably in the range from 1 to 12 and particularly preferably in the range from 1 to 6.5. The AClogP is based on J. Comput. help Mol. Des. 2005, 19, 453; Virtual Computational Chemistry Laboratory, http://www.vcclab.org.

Suitable coinitiators for a type II photoinitiator system are anionic borates, particularly anionic triarylalkyl borates, which are described in WO 2015/055576. Other coinitiators can be pentacoordinate silicates or tertiary aromatic amines.

In a preferred embodiment of the photopolymer composition, the at least one dye has the structure of formula (II), wherein

R ²⁰⁵ is hydrogen, C ₁ - to C ₄ -alkyl, or NR ²¹⁰ R ²¹¹ ,

R ²⁰⁶ is hydrogen, C ₁ - to C ₄ -alkyl, or NR ²¹² R ²¹³ ,

R ²⁰¹ to R ²⁰⁴ and R ²¹⁰ to R ²¹³ are each independently hydrogen, methyl, ethyl, propyl, butyl, chloroethyl, cyanomethyl, cyanoethyl, methoxyethyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, benzyl, phenyl, tolyl, anisyl or chlorophenyl or

NR ²⁰¹ R ²⁰² , NR ²⁰³ R ²⁰⁴ , NR ²¹⁰ R ²¹¹ and NR ²¹² R ²¹³ independently represent pyrrolidino, piperidino, morpholino or N-methylpiperazino,

R ²⁰⁷ to R ²⁰⁹ are hydrogen and the two optional bridging groups X ¹ and X ² are independently SiMe ₂ or O.

In a preferred embodiment of the photopolymer composition, the at least one dye has a structure of the formula (XVX): wherein R ²⁰¹ to R ²⁰⁴ and R ²¹⁰ to R ²¹³ are each independently hydrogen or methyl, ethyl, propyl or butyl. In a preferred embodiment of the photopolymer composition, the at least one dye of the formula (1) or formula (XVX) present has an organically substituted sulfonate as anion (An-).

In a preferred embodiment of the photopolymer composition, the at least one coinitiator is a triarylalkyl borate salt.

In a preferred embodiment of the photopolymer composition, the coinitiator contains a triarylalkyl borates according to formula (III) which have a calculated oxidation potential between 1.01 V vs. SCE and 1.31 V vs. SCE in acetonitrile and wherein

A is a methylene group or an arbitrarily substituted methine group which can optionally form a ring with up to 10 members with R ¹⁰ ,

R ¹⁰⁰ is hydrogen or a C ₁ - to C ₂₀ -alkyl, C 3 - to C 20 -alkenyl, C ₃ - to C _{20 -, optionally substituted by hydroxy and/or alkoxy and/or acyloxy and/or halogen, C 3 -} to C ₂₀ - alkynyl, C ₅ - to C ₇ -cycloalkyl or C ₇ - to C ₁₃ -aralkyl radical,

R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ each represent up to five independently selected radicals from C ₁ - to C ₂₀ -alkyl-, C ₃ - to C ₅ -alkenyl-, C ₃ - to C ₅ -alkynyl-, C _{C 5} - to C ₇ -cycloalkyl or C ₇ - to C ₁₃ -aralkyl, halogen, cyano, trifluoromethyl, trichloromethyl, difluoromethyl, dichloromethyl, trifluoromethylthioyl, trichloromethylthioyl, C ₁ - to C ₁₂ -alkoxy, Trifluoromethoxy, trichloromethoxy, C ₁ - to C ₁₂ -alkylthioyl, thioyl, difluoromethoxy, difluoromethylthioyl, carboxyl, carbonyl, 2-, 3-, or 4-pyridyl, or aryl radicals substituted in any way, or are hydrogen, the selection of the radicals being dependent on the fact that the calculated oxidation potential of the triaryl alkyl borate (111), which is dependent on the radicals, is in a range between 1.01 V vs. SCE and 1.31 V vs. SCE in acetonitrile,

K ⁺ is any substituted organocation of valence n based on nitrogen, phosphorus, oxygen, sulfur and/or iodine and n is 1, 2 or 3. In this embodiment of the photopolymer composition, A is preferably a methylene group.

In a preferred embodiment of the photopolymer composition, for the triaryl alkylborate of structure (111), R ¹⁰⁰ is C ₁ - to C ₂₀ -alkyl, C ₅ - to C ₇ -cycloalkyl, or C ₇ - to C 13 - aralkyl and R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ are each one to two independently selected radicals from C ₁ - to C ₄ -alkyl, halogen, cyano, trifluoromethyl, C ₁ - to C ₄ -alkoxy or any substituted aryl radicals or hydrogen. At least one radical selected from the radicals R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ is preferably not hydrogen. In the case of two radicals R ¹⁰¹ , two R ¹⁰² , and two R ¹⁰³ each, the two radicals are preferably in the meta position and para position relative to the B atom on the aromatic compound. In this embodiment, A is preferably a methylene group.

More preferably, for the triarylalkyl borate of structure (11), R ¹⁰⁰ is C ₃ to C ₅ alkyl, preferably A is methylene, and at least one of R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ is one to two , In the meta and / or para position, independently selected radicals from C ₁ - to C ₄ alkyl radicals and halogen substituents, preferably at least R ¹⁰² and / or R ¹⁰³ independently selected halogen substituents, with halogen substituents next to Halogen radicals such as Cl radical or F radical also trihaloalkyl radicals, especially trihalomethyl radicals and trihaloethyl radicals, especially trifluoromethyl radicals and trichloromethyl radicals.

In another preferred embodiment of the photopolymer composition, for the triarylalkyl borate of structure (11), R ¹⁰⁰ is a C ₃ - to C ₁₂ -alkyl radical, R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ are each independently one to two, in meta - or para-position radicals selected from the group consisting of C ₁ - to C ₄ -alkyl radicals and halogen substituents, preferably at least R ¹⁰² and / or R ¹⁰³ for a halogen substituent. In the case of two radicals R ¹⁰¹ , two R ¹⁰² , and two R ¹⁰³ each, the two radicals are preferably in the meta position and para position to the B atom. In this embodiment, A is preferably a methylene group.

Further preferably, for the triarylalkyl borate of structure (11), R ¹⁰⁰ is C ₃ - to C ₅ -alkyl, where A is preferably a methylene group and R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ are each one to two, in meta- and/or para position, independently selected radicals from C ₁ - to C ₄ -alkyl radicals and halogen substituents, preferably at least R ¹⁰² and/or R ¹⁰³ for a halogen substituent. The triarylalkyl borates shown below are very particularly preferred, where K ⁺ is in each case any organocation based on nitrogen, phosphorus, oxygen, sulfur or iodine: In a preferred embodiment of the photopolymer composition, the organocation K ⁺ of the triarylalkyl borate salt is a nitrogen or phosphorus based mono or divalent cation, preferably is a nitrogen based mono or divalent cation, most preferably is a monovalent ammonium cation

In a preferred embodiment of the photopolymer composition, the at least one coinitiator, in particular in combination with one of the cationic dyes described above, has an oxidation potential in acetonitrile calculated according to formula (1) 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 more preferably between 1.01 V vs SCE and 1.15 V vs SCE. Furthermore, K ⁺ can be an organocation of valency n based on nitrogen, such as ammonium ions, pyridinium ions, pyridazinium ions, pyrimidinium ions, pyrazinium ions, imidazolium ions, pyrrolidinium ions, which optionally have other functional groups such as ethers in one or more side chains Wear esters, amides and / or carbamates and can also be present in oligomeric or polymeric or bridging form. K ⁺ is preferably an n-based organocation based on phosphorus, such as an optionally substituted tetraalkyl phosphonium, trialkyl aryl phosphonium, dialkyl diaryl phosphonium, alkyl triaryl phosphonium, or tetraaryl phosphonium cation, which may carry further functional groups such as carbonyls, amides and/or carbamates in one or more side chains and which may also be present in oligomeric or polymeric or bridging form.

More preferably, K ⁺ is an organocation of valency n based on oxygen, such as any substituted pyrylium cation, which can also be present in fused form, such as in benzopyrylium, flavylium, or naphthoxanthenium cation, or a polymeric cation with the substitution patterns mentioned.

More preferably, K ⁺ is an n-valency organocation based on sulfur, such as an onium compound of sulfur, the same or different optionally substituted C ₄ - to C ₁₄ -alkyl, C ₆ - to C _{C 10} -aryl, C ₇ - to C ₁₂ - arylalkyl or C ₅ - to C ₆ -cycloalkyl radicals and / or oligomeric or polymeric recurring connecting units to form sulfonium salts with 1 ≤ n ≤ 3 can build up, or such as thiopyrylium Cations or polymeric cations with the substitution patterns mentioned.

K ⁺ is furthermore preferably an organocation of valency n based on iodine, such as an onium compound of iodine, the same or different optionally substituted C ₁ - to C ₂₂ -alkyl, C ₆ - to C ₁₄ - Carry aryl, C ₇ - to C ₁₅ -arylalkyl or C ₅ - to C ₇ -cycloalkyl radicals and/or oligomeric or polymeric recurring connecting units to form iodonium salts with 1≦n≦3, or other polymeric cations with those mentioned substitution pattern.

The photoinitiator system can also contain a further coinitiator clll), such as, for example, trichloromethyl initiators, iodonium salts, sulfonium salts, aryl oxide initiators, bisimidazole initiators, ferrocene initiators, oxime initiators, thiol initiators or peroxide initiators.

It can be advantageous to use mixtures of these coinitiators and different dyes. Depending on the radiation source used, the type and concentration of the PIS must be adjusted in a manner known to those skilled in the art. More details are described, for example, in PKT Oldring (Ed.), Chemistry & Technology of UV & EB Formulations For Coatings, Inks & Paints, Vol. 3, 1991, SITA Technology, London, pp. 61-328. It is very particularly preferred if the PIS comprises a combination of dyes whose absorption spectra at least partially cover the spectral range from 400 to 1200 nm, with at least one coinitiator tailored to the dyes. It is also preferred if at least one photoinitiator suitable for a laser light color is present in the photopolymer composition. It is also more preferred if the photopolymer composition is selected for at least two laser light colors blue, green and red and NIR each contains a suitable photoinitiator. Finally, it is very particularly preferred if the photopolymer composition contains a suitable photoinitiator for each of the laser light colors.

The at least one non-photopolymerizable component d) can be any component d) that one skilled in the art would select for the photopolymer composition of the present invention. It is preferably provided that the photopolymer composition additionally contains urethanes as additives of component d), it being possible in particular for the urethanes to be substituted with at least one fluorine atom.

The urethanes can preferably have the general formula (XVIII) have, in which o ≥ 1 and o ≤ 8 and R ⁷ , R ⁸ and R ⁹ are linear, branched, cyclic or heterocyclic unsubstituted or optionally substituted with heteroatoms organic radicals and / or R ⁸ , R ⁹ are independently hydrogen, where preferably at least one of the radicals R ⁷ , R ⁸ , R ⁹ is substituted with at least one fluorine atom and particularly preferably R ⁷ is an organic radical with at least one fluorine atom. R ⁹ is particularly preferably a linear, branched, cyclic or heterocyclic organic radical which is unsubstituted or optionally also substituted by heteroatoms such as, for example, fluorine.

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

The statements made above in relation to the photopolymer composition according to the invention with regard to further preferred embodiments also apply analogously to the photopolymer according to the invention.

Another subject of the present invention relates to a layer structure containing at least the layers:

A. a substrate layer A, which may be part of a further layer structure,

B. a photopolymer layer B formed from the photopolymer composition according to the invention, and

C. a cover layer C, which is optionally part of the further layer structure.

Another subject of the present invention relates to a layer structure containing at least the layers: A. a substrate layer A, which is optionally part of a further layer structure, B'. an exposed or cured photopolymer layer B', which was produced from the photopolymer composition according to the invention by curing with light, and

C. a cover layer C, which is optionally part of the further layer structure.

Also disclosed is a method of making a holographic medium using a disclosed photopolymer composition. In particular, the photopolymer compositions can be used to produce holographic media in the form of a film. Here, as carrier A, a layer of a material or material composite that is transparent to light in the visible and NIR spectral range (transmission greater than 85% in the wavelength range from 400 to 1200 nm) is coated in the dark on one or both sides with the photopolymer composition B and, if necessary, A covering layer C is applied to the photopolymer layer or layers B. Preferred materials or composite materials of 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 poly lydicyclopentadiene or mixtures thereof. They are particularly preferably based on PC, PET and CTA. Material composites can be film laminates or coextrudates. Preferred composite materials are duplex and triplex films constructed according to one of the schemes A/B, A/B/A or A/B/C. PC/PET, PET/PC/PET and PC/TPU (TPU=thermoplastic polyurethane) are particularly preferred. The materials or composite materials of the carrier can be made anti-adhesive, antistatic, hydrophobic or hydrophilic on one or both sides. On the side facing the photopolymer layer B, the modifications mentioned serve the purpose that the photopolymer layer B can be detached from the carrier A without being destroyed. A modification of the side of the support facing away from the photopolymer layer B serves to ensure that the media according to the invention meet special mechanical requirements which are required, for example, when processing in roll laminators, in particular in roll-to-roll processes.

In addition, another method of making a holographic media using a photopolymer composition of the present invention is disclosed which also yields holographic media in the form of films. The carrier A is a layer of a material or material composite that is transparent to light in the visible and NIR spectral range (transmission greater than 85% in the wavelength range from 400 to 1200 nm) in the dark with the photopolymer composition B on one side by means of 2D printing and, if necessary, a Cover layer C on the photopolymer layers B or applied. All common inkjet technologies can be used. If necessary, only the areas required for the function can be targeted with the Photopolymer composition B are printed. Preferred materials or material composites 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 particularly preferably based on PC, PET and CTA. Material composites can be film laminates or coextrudates. Preferred composite materials are duplex and triplex films constructed according to one of the schemes A/B, A/B/A or A/B/C. PC/PET, PET/PC/PET and PC/TPU (TPU=thermoplastic polyurethane) are particularly preferred. The materials or composite materials of the carrier can be made anti-adhesive, antistatic, hydrophobic or hydrophilic on one or both sides. On the side facing the photopolymer layer B, the modifications mentioned serve the purpose that the photopolymer layer B can be detached from the carrier A without being destroyed. A modification of the side of the support facing away from the photopolymer layer B serves to ensure that the media according to the invention meet special mechanical requirements which are required, for example, when processing in roll laminators, in particular in roll-to-roll processes.

Also disclosed are material composites of the type described above, containing a photoexposed, preferably light-cured photopolymer layer B', resulting in duplex and triplex films according to a scheme A/B', A/B'/A or A/B7C .

Holographic information can be imprinted in such holographic media.

A further subject matter of the invention relates to a holographic medium containing a photopolymer composition according to the invention. Holographic media can be processed into holograms by appropriate exposure processes for optical applications in the red and NIR range (600-1200 nm). Visual holograms and holograms that work in the NIR range include all holograms that can be recorded using methods known to those 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.

Another subject matter of the invention relates to a holographic medium that 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 one Combination of at least two of these, combinations of these hologram types or several holograms of the same type can also be combined independently of one another in the same volume of the holographic medium (multiplexing).

Possible optical functions of the holograms that 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, diffusers, diffraction elements, diffusers, light guides, light guides (waveguides), projection screens and/or or masks. Combinations of these optical functions can also be combined independently of one another in a hologram (multiplexing). These optical elements often exhibit frequency selectivity, depending on how the holograms were exposed and the dimensions of the hologram.

The functions of the holograms described above, which can be produced with the photopolymer compositions according to the invention, are, for example, but not exclusively, in the areas of eye tracking, sensing, as well as LID AR and augmented reality, head-mounted display and virtual reality applications NIR range used.

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

In addition, holographic images or representations can also be produced using holographic media, such as for personal portraits, biometric representations in security documents, or generally of images or image structures for advertising, security labels, brand protection, branding, labels, design elements, decorations, illustrations , trading cards, images and the like, as well as images that can represent digital data, including in combination with the products presented 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, the (also moving) light source etc. used to illuminate them. Due to these diverse design options, holograms, especially volume holograms, represent an attractive technical solution for the above application.

Another subject of the invention relates to the use of a holographic medium according to the invention for the production of chip cards, ID documents, 3D images, product protection labels, labels, banknotes or holographic optical elements, in particular for optical displays or in media for implementing methods selected from the group consisting of eye tracking, sensing, LID AR, augmented reality, head-mounted display and virtual reality applications, in particular in the near infrared range and a combination of at least two of these. The holographic media can be used to record in-line, off-axis, full-aperture transfer, white-light transmissions, Denisyuk, off-axis reflections or edge-lit holograms and holographic stereograms, in particular for the production of optical elements, images or Image representations are used.

Holograms are accessible from holographic media according to the invention through appropriate exposure.

Examples and character description:

The following examples serve to explain the invention by way of example without restricting it to these.

Measurement of the OH number and the NCO value:

OH number: The OH numbers given were determined in accordance with DIN 53240-2.

NCO value: The specified NCO values (isocyanate content) were in accordance with DIN EN ISO

11909 determined.

Measurement of the holographic properties DE and Δn of the holographic media / photopolymer films using two-beam interference in a reflection arrangement:

The beam of a NIR laser (emission wavelength 850 nm) was converted into a parallel homogeneous beam with the help of the spatial filter (SF) and together with the collimating lens (CL). The final cross-sections of the signal and reference beam are determined by the iris diaphragms (I). The diameter of the iris aperture is 0.4 cm. The polarization dependent beam splitters (PBS) split the laser beam into two coherent beams with the same polarization. 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 λ/2 plates. The power was determined with the semiconductor detectors (D) with the sample removed. The angle of incidence (α ₀ ) of the reference beam is -21.8°, the angle of incidence (β ₀ ) of the signal beam is 41.8°. The angles are measured from the sample normal to the beam direction. According to Scheme 1, therefore, α ₀ has a negative sign and β ₀ has a positive sign. At the location of the sample (medium), the interference field of the two overlapping beams produced a lattice of light and dark fringes perpendicular to the bisector of the two beams incident on the sample (reflection hologram). The stripe spacing Λ, also called the grating period, in the medium is ~ 296 nm (the refractive index of the medium is assumed to be ~1.51).

Figure 1 shows the holographic test setup with which the diffraction efficiency (DE) of the media was measured, Figure 1 showing the geometry of a holographic media tester (HMT) at λ = 850 nm (NIR laser) (M = mirror, S = shutter, SF = spatial filter, CL = collimator lens, λ/2 = λ/2 plate, PBS = polarization-sensitive beamsplitter, D = detector, I = iris, α ₀ = -21.8°, β ₀ = 41.8° are the angles of incidence of the coherent rays measured outside the sample (the medium), RD = reference direction of the turntable) is shown.

Holograms were written into the medium in the following way:

• Both shutters (S) are open for the exposure time t.

• Then, with the shutters (S) closed, the medium was allowed 5 minutes for the diffusion of the writing monomers that had not yet polymerized.

The written holograms were now read out in the following way. The shutter of the signal beam remained closed. The reference beam shutter was open. The iris diaphragm of the reference beam was closed to a diameter < 1 mm. This meant that for all angles of rotation (Ω) of the medium, the beam was always completely within the previously written hologram. Computer-controlled, the rotary table now covered the angular range from Ω _min to Ω _max with an angular increment of 0.05°. Ω is measured from the sample normal to the turntable reference direction. The reference direction of the rotary table results when the angles of incidence of the reference and signal beams are the same when writing the hologram, ie α ₀ =−31.8° and β ₀ =31.8° applies. Then Ω _recording = 0°. For α ₀ = -21.8° and β ₀ = 41.8°, Ω _recording is therefore 10°. In general, the following applies to the interference field when writing (“recording”) the hologram: α ₀ = θ ₀ + Ω _recording . (3) θ ₀ is the semi-angle in the laboratory frame outside the medium and when writing the hologram:

In this case, θ ₀ = -31.8°. At each rotation angle Ω approached, the powers of the beam transmitted in the zeroth order were measured by means of the corresponding detector D and the powers of the beam diffracted to the first order by means of the detector D. The diffraction efficiency resulted at each approached angle Ω as the quotient of:

P _D is the power in the diffracted beam detector and P _T is the power in the transmitted beam detector.

Using the method described above, the Bragg curve, which describes the degree of diffraction η as a function of the angle of rotation Ω, of the written hologram was measured and stored in a computer. In addition, the intensity transmitted to the zeroth order was plotted against the rotation angle Ω. recorded and stored in a computer. The maximum diffraction efficiency (DE = η _max ) of the hologram, i.e. its peak value, was determined at Ω _{reconstruction} . It may have been necessary to change the position of the deflected beam detector in order to determine this maximum value.

The refractive index contrast Δn and the thickness d of the photopolymer layer was now 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 determines the angular progression of the transmitted intensity. It should be noted that because of the shrinkage in thickness that occurs as a result of the photopolymerization, the stripe spacing Λ ' of the hologram and the orientation of the strips (slant) can deviate from the stripe spacing A of the interference pattern and its orientation. Accordingly, the angle α ₀ ' or the corresponding angle of the turntable Ω _{reconstruction} at which maximum diffraction efficiency is achieved will also deviate from α ₀ or from the corresponding Ω _recording . This changes the Bragg condition. This change is taken into account in the evaluation process. The evaluation procedure is described below:

All geometric quantities related to the written hologram and not to the fringe pattern are represented as dashed quantities.

According to Kogelnik, the following applies to the Bragg curve η (Ω) of a reflection hologram:

When reading out the hologram (“reconstruction”), the same applies as shown above:

At the Bragg condition, the “dephasing” is DP = 0. And it follows accordingly: α ' ₀ = θ ₀ + Ω _{rec on structure}

(16) sin(α ' ₀ ) = n • sin(α ') (17)

The angle β', which is still unknown, can be determined by comparing the Bragg condition of the interference field when writing the hologram and the Bragg condition when reading the hologram, assuming that only thickness shrinkage takes place. Then follows: v is the grid strength, ξ, is the detuning parameter and the orientation (slant) of the refractive index grating that was written, α ' and β' correspond to the angles α ₀ and β ₀ of the interference field when writing the hologram, but measured in the medium and valid for the grating of the hologram (after thickness shrinkage), n is the average refractive index of the photopolymer and was set at 1.51. λ is the wavelength of the laser light in a vacuum.

The maximum diffraction efficiency (DE = η _max ) then results for ξ = 0:

As shown in FIG. 2, the measurement data of the diffraction efficiency, the theoretical Bragg curve and the transmitted intensity are plotted against the centered angle of rotation ΔΩ=Ω _{reconstruction} −Ω=α′ ₀ −ϑ′ ₀ , also known as angle tuning. FIG. 2 shows the measured transmitted power P _T (right y-axis) as a solid line (here of example 3a) plotted against the angle tuning ΔΩ, the measured diffraction efficiency η (left y-axis) as filled circles against the angle tuning ΔΩ plotted (as far as the finite size of the detector allowed) and the fitting of the Kogelnik theory as a dashed line (left y-axis).

Since DE is known, the shape of the theoretical Bragg curve according to Kogelnik is only determined by the thickness d' of the photopolymer layer. Δn will be about DE for a given thickness d' like this corrected that measurement and theory of DE always agree. d' is now adjusted until the angular positions of the first secondary minima of the theoretical Bragg curve match the angular positions of the first secondary maxima of the transmitted intensity and the full width at half height (FWHM) for the theoretical Bragg curve and for the transmitted intensity also match.

Since the direction in which a reflection hologram also rotates during reconstruction using an Ω scan, but the detector for the diffracted light can only detect a finite angle range, the Bragg curve of wide holograms (small d') does not appear with an Ω scan completely recorded, but only the central area, with suitable detector positioning. Therefore, the form of the transmitted intensity, which is complementary to the Bragg curve, is also used to adjust the layer thickness d′.

FIG. 2 shows the Bragg curve η according to the coupled wave theory (dashed line), the measured diffraction efficiency (filled circles) and the transmitted power (solid black line) versus the angle tuning ΔΩ.

For a formulation, this procedure may have been repeated several times for different exposure times t on different media in order to determine at which average energy dose of the incident laser beam DE reaches the saturation value when writing the hologram. The mean absorbed dose E is calculated as follows from the power of the two partial beams assigned to the angles α ₀ and β ₀ (reference beam with P _r = 1.75 mW and signal beam with P _s = 2.25 mW), the exposure time t and the diameter the iris diaphragm (0.4 cm):

The powers of the partial beams were adjusted in such a way that the same power density is achieved in the medium at the angles α ₀ and β ₀ used.

Calculation of the oxidation potential of triaryl alkyl borates:

The absolute oxidation potential ), referenced against the saturated calomel electrode, was calculated using the following formula (2):

Here n _e is the number of transferred electrons (here always n _e = 1), F is the Faraday constant the absolute potential value of the standard hydrogen electrode (SHE) the potential of the saturated calomel electrode (SCE) relative to the SHE in Acetonitrile and G ₂₉₈ and G ₂₉₈ (oxidized) each the calculated Gibbs energies at 298 K of the ground state and the oxidized state of the triaryl alkyl borate.

After inserting the constants mentioned above, formula (2) can also be expressed as follows (formula (1)):

The Gibbs energies at 298 K of the ground state and the oxidized state were calculated as follows: First, the three-dimensional molecular geometry of the triaryl alkyl borate was generated with ChemDraw 3D and subjected to a conformer analysis. The conformers found were energetically minimized using the AMI force field and the obtained coordinates of the molecular geometries (usually only one conformer was obtained) were used to calculate the electronic energy. The electronic ground state was geometry-optimized in a suitable solvent (PCM approach for acetonitrile) and the absolute electronic energies of the optimized structures were determined and corrected for the influence of the solvent field (G ₂₉₈ ). The molecule geometry optimized in this way was then reduced by one electron and the absolute electronic energy - also calculated in acetonitrile (PCM method) - of the oxidized molecule was determined again (G ₂₉₈ (oxidized)).

Substances:

The solvents, reagents and all bromine aromatics used were obtained from chemical dealers. The bromo aromatics may have been freshly distilled. Anhydrous solvents contain < 50 ppm water.

Polyol 1 was prepared as described in WO2015091427 with an OH

number of 56.8.

Desmodur® N 3900 Product from Covestro AG, Leverkusen, DE, hexanediisocyanate-based polyisocyanate, proportion of iminooxadiazinedione at least 30%, NCO content: 23.5%.

Ferric trifluoroacetylacetonate [14526-22-8] is available from ABCR GmbH & Co. KG, Karlsruhe, Germany.

Urethane acrylate 1 (phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl)trisacrylate, [1072454-85-3]) was prepared as described in WO2015091427. Urethane acrylate 2 (2-({[3-(methylsulfanyl)phenyl]carbamoyl}oxy)-ethylprop-2-enoate, [1207339-61-4]) was prepared as described in WO2015091427.

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.

Karenz™ 1R-T obtained from Showa Denko EUROPE GmbH, [96233-24-8].

Karenz™ P3B obtained from Showa Denko EUROPE GmbH, [120307-06-4].

cation 2 N ₁ , N ₂₂ -dihexadecyl- N ₁ , N ₁ , N ₂₂ , N ₂₂ , 10,10, 13-heptamethyl-7, 16-di-oxo-3,6, 17,20-tetraoxa-8 , 15-diazadocosan-l, 22-diaminium dibromide was prepared as described in WO 2018087064.

BYK-310 Silicone surface additive, product of BYK-Chemie

GmbH, Wesel, Germany.

Synthesis Rules:

Instructions for the preparation of 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): 4.08 g sodium bis(2-ethylhexyl)sulfosuccinate (1.0 eq.) was dissolved in 80 mL deionized water. 7.44 g of Karenz 1R-T (1.0 eq.) in 100 mL of butyl acetate were added to this solution, and the two-phase mixture was stirred at RT for 3 h. The aqueous phase was then separated off and the organic phase was washed five times with 80 mL deionized water each time. Finally, the solvent was removed in vacuo 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):

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

Preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² =R ¹⁰³ :

In a four-necked flask equipped with a thermometer, reflux condenser, addition funnel, and magnetic stirrer, the appropriate diisopropyl alkyl borate (1.0 eq.) and magnesium turnings (3 eq.) are dissolved in a solvent mixture consisting of dry toluene and dry THF (5.8:1, 1.9 M) submitted. This mixture is stirred at room temperature for 30 min. The corresponding bromoaromatic (3 eq.) is then added dropwise to the mixture, initially undiluted, until the onset of exothermicity signals the start of the reaction, but a maximum of 10% of the undiluted bromoaromatic is used for this purpose. The remainder 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 the total molarity to 0.4 M) in such a way that the reaction temperature does not exceed 45.degree. After the addition is complete, the reaction solution is refluxed until the magnesium has completely dissolved or for 1 hour. The reaction solution is cooled to room temperature and poured onto a mixture consisting of ice water and tetrabutylammonium bromide (1 eq.). The mixture is stirred for 1 hour and then the organic phase is separated off. The organic phase is washed with water until a halide test (HNO ₃ (aq., 10%)+AgNOfl is negative. The solvents are removed in vacuo on a rotary evaporator and the crude product is recrystallized from methanol.

Preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² ≠R ¹⁰³ :

The appropriate diisopropyl alkyl borate (1.0 eq.) and magnesium turnings (3 eq.) in a solvent mixture consisting of dry toluene and dry THF (4:1, 1.9 M) are placed in a four-necked flask equipped with a thermometer, reflux condenser, dropping funnel and magnetic stirrer . This mixture is stirred at room temperature for 30 min. The first bromoaromatic (1 eq.) is then added undiluted to the mixture dropwise until the onset of exothermic signals the start of the reaction, but a maximum of 10% of the undiluted bromoaromatic is used for this. The remainder 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 the total molarity to 0.7 M) in such a way that the reaction temperature does not exceed 45.degree. After the addition is complete, the reaction solution is stirred at RT for 1 h. Then the corresponding second aromatic bromine is first added dropwise undiluted to the mixture until the onset of exothermic signals the start of the reaction, however, a maximum of 10% of the undiluted aromatic bromine is used for this. The remainder of the bromoaromatic is again added dropwise to the reaction solution in the remaining solvent mixture consisting of dry toluene and dry THF (1.1:1, dilution of the total molarity to 0.4 M) in such a way that the reaction temperature does not exceed 45.degree. After the addition is complete the reaction solution is heated under reflux until the magnesium has completely dissolved or for 1 hour. The reaction solution is cooled to room temperature and poured onto a mixture consisting of ice water and tetrabutylammonium bromide (1 eq.). The mixture is stirred for 1 hour and the organic phase is separated off. The organic phase is washed with water until a halide test (HNO ₃ (aq., 10%)+AgNO ₃ ) is negative. The solvents are removed in vacuo on a rotary evaporator and the crude product is recrystallized from methanol.

Preparation instructions for triaryl alkyl borates with cations of valency n=l:

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

Preparation instructions for triaryl alkyl borates with cations with a valence of n=2:

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

Manufacturing instructions for photopolymer film / holographic media:

14.9 g of the polyol component 1 described above are melted and mixed in the dark with 6.6 g of the urethane acylate 1, 6.6 g of the 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 colorant 1, 0.12 g BYK-310, 0.01 g ferric trifluoroacetylacetonate, 10.5 g ethyl acetate, 1.1 g butyl acetate and 7 .7 g of 1-methoxy-2-propyl acetate mixed so that a homogeneous solution is obtained. Then 2.8 g of Desmodur® N 3900 are added and mixed again. This solution is applied to a 60 μm thick TAC film in a roll-to-roll coating system in the dark and applied using a squeegee in such a way that a wet layer thickness of 14-17 μm is achieved. The coated film is dried at a drying temperature of 80° C. and a drying time of approx. 4 minutes and then protected with a 40 μm thick polyethylene film. This film is then packed in a light-tight manner.

Preparation of N-Benzyl-N,N-dimethylhexadecylammoniumdi-(3-chloro-4-methylphenyl)-(4-methylphenylhexylborate: 3-Chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ ═R 102 ≠ ^{R 103} . The tetrabutylammonium triarylhexylborate obtained was then reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate in accordance with the general preparation instructions for triarylhexylborates with cations of valence n=1. A colorless oil (18.92 g, 42% of theory over two stages) with a signal in the ¹¹ B NMR spectrum at δ (ppm) (CDCl ₃ )=−10.6 ppm was obtained. The calculated reduction potential was E _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):

A photopolymer with N-benzyl-N,N-dimethylhexadecylammonium di-(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate as coinitiator was produced in accordance with the general production instructions for photopolymer films.

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

3-Chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² ≠R ¹⁰³ . The general instructions for the preparation of triarylalkyl borates with cations of valence n=1 were then followed using cation 1. A colorless oil (2.5 g, 42% of theory over two stages) with a signal in the ¹¹ B-NMR Spectrum obtained at δ (ppm) (CDCl ₃ ) = -10.6 ppm. The calculated reduction potential was E _ox = 1.02 V vs. SCE in acetonitrile.

Production of a photopolymer with N-(3-phenylpropyl)-N,N-dimethylhexadecyl-ammonium di-(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate (Example 3b in Table 2):

A photopolymer with N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium di-(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate as a coinitiator was prepared in accordance with the general manufacturing instructions for photopolymer films.

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

3-Chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² ≠R ¹⁰³ . Then the general instructions for the preparation of triaryl alkyl borates with cations of valence n=1 were followed using tributyltetradecylphosphonium bromide. It was a colorless oil (1.2 g, 42% d. Theory over two stages) with a Signal obtained in ¹¹ B NMR spectrum at δ (ppm) (CDCl ₃ ) = -10.6 ppm. The calculated reduction potential was E _ox = 1.02 V vs. SCE in acetonitrile.

Production of a photopolymer with tributyltetradecylphosphonium di-(3-chloro-4-methylphenyl)(4-methylphenyl)hexyl borate (example 3c in Table 2):

A photopolymer with tributyltetradecylphosphonium di-(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate as co-initiator was produced in accordance with the general production instructions for photopolymer films.

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

3-Chloro-4-methylbromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² ≠R ¹⁰³ . Subsequently, the general instructions for the preparation of triaryl alkyl borates with cations of valence n=1 were followed using cation 2. A colorless oil (2.7 g, 42% of theory over two stages) with a signal im ¹¹ B NMR spectrum obtained at δ (ppm) (CDCl ₃ ) = -10.6 ppm. The calculated reduction potential was E _ox = 1.02 V vs. SCE in acetonitrile.

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

According to the general manufacturing instructions for photopolymer films, a photopolymer with N ₁ ,N ₂₂ -dihexadecyl-N ₁ ,N ₁ ,N ₂₂ ,N ₂₂ ,10,10,13-heptamethyl-7,16-dioxo-3,6,17, 20-tetraoxa-8,15-diazadocosan-1,22-diaminium-bis-di-(3-chloro-4-methylphenyl)(4-methylphenyl)hexylborate as a co-initiator.

Preparation of N-Benzyl-N,N-dimethylhexylammonium di-(4-chlorophenyl)(4-methyl-phenyl)hexylborate:

4-Chlorobromobenzene (2 eq.) and 4-methylbromobenzene (1 eq.) were reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² ≠R ¹⁰³ . The resulting tetrabutylammonium triarylhexylborate was then reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate in accordance with the general preparation instructions for triarylhexylborates with cations of n=1 valence. A colorless oil (2.4 g, 60% of theory over two stages) with a signal in the ¹¹ B NMR spectrum at δ (ppm) (CDCl ₃ )=−10.7 ppm was obtained. The calculated reduction potential was E _ox = 1.03 V vs. SCE in acetonitrile. Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium di-(4-chlorophenyl)(4-methylphenyl)hexyl borate (Example 8 in Table 2):

A photopolymer with N-benzyl-N,N-dimethylhexadecylammonium di-(4-chlorophenyl)(4-methylphenyl)hexylborate as a coinitiator was prepared in accordance with the general manufacturing instructions for photopolymer films.

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

The preparation instructions published in WO2018/087064 for the preparation of tetrabutylammonium tri-(3-chloro-4-methylphenyl)cyclohexylborate were followed. The general instructions for the preparation of triaryl alkyl borates with cations of valence n=1 were then followed using cation 1. A slightly yellowish oil (5.0 g, 99% of theory) with a signal in the ¹¹ B NMR Spectrum obtained at δ (ppm) (CDCl ₃ ) = -8.7 ppm. The calculated reduction potential was E _ox = 1.03 V vs. SCE in acetonitrile.

Production of a photopolymer with N-(3-phenylpropyl)-N,N-dimethylhexadecylammoniumtri-(3-chloro-4-methylphenyl)cyclohexylborate (Example 11 in Table 2):

A photopolymer containing N-(3-phenylpropyl)-N,N-dimethylhexadecylammonium tri-(3-chloro-4-methylphenylcyclohexylborate) as a coinitiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of N-Benzyl-N,N-dimethylhexadecylammoniumdiphenyl-(3-chloro-4-methyl-phenyl)hexylborate:

Bromobenzene (2 eq.) and 3-chloro-4- ^{methylbromobenzene} (1 eq.) were reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² ≠R 103 . The product of the reaction was obtained after a silica gel column chromatography (dichloromethane/toluene 70:30). The tetrabutylammonium triarylhexylborate obtained was then reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate in accordance with the general preparation instructions for triarylhexylborates with cations of valence n=1. A colorless oil (0.68 g, 76% of theory over two stages) with a signal in the ¹¹ B NMR spectrum at δ (ppm) (CDCl ₃ )=−10.4 ppm was obtained. The calculated reduction potential was E _ox = 1.04 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium-diphenyl(l-(3-chloro-4-methylphenyl)hexylborate (Example 12 in Table 2): A photopolymer with N-benzyl-N,N-dimethylhexadecylammoniumdiphenyl-(3-chloro-4-methylphenyl)hexylborate as co-initiator was produced in accordance with the general production instructions for photopolymer films.

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

Bromobenzene (2 eq.) and 4-fluorobromobenzene (1 eq.) were reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ =R ¹⁰² ≠R ¹⁰³ . The product of the reaction was obtained after a silica gel column chromatography (dichloromethane/toluene 70:30). The tetrabutylammonium triarylhexylborate obtained was then reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate in accordance with the general preparation instructions for triarylalkyl borates with cations of valence n=1. A colorless oil (0.74 g, 34% of theory over two stages) with a signal in the ¹¹ B NMR spectrum at δ (ppm) (CDCl ₃ )=−10.5 ppm was obtained. The calculated reduction potential was E _ox = 1.06 V vs. SCE in acetonitrile.

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

A photopolymer with N-benzyl-N,N-dimethylhexadecylammoniumdiphenyl-(4-fluorophenyl)hexylborate as a coinitiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of N-Benzyl-N,N-dimethylhexadecylammonium tri-(3-chloro-4-methylphenyl)-3-phenylpropyl borate:

The manufacturing instructions published in WO2018/087064 for the manufacture of tetrabutylammonium tri-(3-chloro-4-methylphenyl)-3-phenylpropylborate were followed. The tetrabutylammonium triarylalkyl borate obtained was then reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate in accordance with the general preparation instructions for triarylalkyl borates with cations of valence n=1. A slightly yellowish oil (4.8 g, 99% of theory) with a signal in the ¹¹ B-NMR spectrum at δ (ppm) (CDCl ₃ )=−10.3 ppm was obtained. The calculated reduction potential was E _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):

A photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri-(3-chloro-4-methylphenyl)-3-phenylpropyl borate as a coinitiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of Tetrabutylammonium tri-(4-fluorophenyl)dodecylborate: The manufacturing instructions published in WO2018/087064 for the manufacture of tetrabutylammonium tri-(4-fluorophenyl)dodecylborate were followed. Colorless oil (8.9 g, 12% of theory) with a signal in the ¹¹ B-NMR spectrum at δ (ppm) (CDCl ₃ )=−10.4 ppm was obtained. The calculated reduction potential was E _ox = 1.13 V vs. SCE in acetonitrile.

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

A photopolymer with tetrabutylammonium tri-(4-fluorophenyl)dodecylborate as coinitiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of N-Benzyl-N,N-dimethylhexadecylammonium tri-(3-chloro-4-methyl-phenyl)hexyl borate:

The manufacturing instructions published in WO 2018/099698 were followed. The calculated reduction potential was E _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):

A photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri-(3-chloro-4-methylphenyl)hexylborate as co-initiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of N-Benzyl-N,N-dimethylhexadecylammonium tri-(3-chloro-4-methyl-phenyl)butyl borate:

3-Chloro-4-methylbromobenzene was reacted with diisopropylbutyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ ═R ¹⁰² ═R ¹⁰³ . The tetrabutylammonium triarylbutylborate obtained was then reacted with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate in accordance with the general preparation instructions for triarylalkyl borates with cations of valence n=1. A colorless oil (2.4 g, 24% of theory over two stages) with a signal in the ¹¹ B NMR spectrum at δ (ppm) (CDCl ₃ )=−10.6 ppm was obtained. The calculated reduction potential was E _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):

A photopolymer containing N-benzyl-N,N-dimethylhexadecylammonium tri-(3-chloro-4-methylphenyl)butylborate as co-initiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of Tetrabutylammonium tri-(4-chlorophenyl)hexylborate: 4-Chlorobromobenzene was reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ ═R ¹⁰² ═R ¹⁰³ . Colorless crystals (56 g, 50% of theory) with a signal in the ¹¹ B-NMR spectrum at δ (ppm) (CDCl ₃ )=−9.9 ppm were obtained. The calculated reduction potential was E _ox = 1.17 V vs. SCE in acetonitrile.

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

A photopolymer with tetrabutylammonium tri-(4-chlorophenyl)hexylborate as a coinitiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of N,N-dimethyl-N-(3-phenylpropyl)hexadecyl-ammonium triphenylbutylborate:

Tetrabutylammonium triphenylbutylborate (Karenz P3B) was treated with N-benzyl-N,N-dimethylhexadecylammonium chloride hydrate to form N,N-dimethyl-N-(3-phenylpropyl)-hexadecyl- ammonium triphenylbutyl borate implemented. A colorless amorphous solid was obtained (54 g, >99% of theory) with a signal ¹¹ B-NMR spectrum at δ (ppm) (CDCl ₃ ) = -10.3 ppm. The calculated reduction potential was E _ox = 1.00 V vs. SCE in acetonitrile..

Preparation of a photopolymer with N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium triphenylbutylborate (example NEB1 in Table 2):

A photopolymer with N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium triphenylbutylborate as coinitiator was produced in accordance with the general production instructions for photopolymer films.

Preparation of N-Benzyl-N,N-dimethylhexadecylammonium tri-(3-chlorophenyl)hexyl borate:

3-Chlorobromobenzene was reacted with diisopropylhexyl borate in accordance with the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ ═R ¹⁰² ═R ¹⁰³ . The general instructions for preparing triaryl alkyl borates with cations of valence n=1 were then followed using N-benzyl-N,N-dimethylhexadecyl-ammonium chloride hydrate. A colorless oil (2.5 g, 50% of theory over two stages) with a signal in the ¹¹ B NMR spectrum at δ (ppm) (CDCl ₃ )=−10.1 ppm was obtained. The calculated reduction potential was E _ox = 1.32 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri-(3-chlorophenyl)hexyl borate (example NEB2 in Table 2):

A photopolymer with N-benzyl-N,N-dimethylhexadecylammonium tri-(3-chlorophenyl)hexylborate as coinitiator was produced in accordance with the general production instructions for photopolymer films. Preparation of N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium tri-(4-trifluoromethylphenyl)hexyl borate:

4-Bromobenzene trifluoride was reacted with diisopropylhexyl borate according to the general preparation instructions for tetrabutylammonium triarylalkyl borates with R ¹⁰¹ ═R ¹⁰² ═R ¹⁰³ . The general instructions for the preparation of triarylalkyl borates with cations of valence n=1 were then followed using cation 1. A colorless oil (2.5 g, 22% of theory over two stages) with a signal in the ¹¹ B-NMR Spectrum obtained at δ (ppm) (CDCl ₃ ) = -10.0 ppm. The calculated reduction potential was E _ox = 1.45 V vs. SCE in acetonitrile.

Preparation of a photopolymer with N,N-dimethyl-N-(3-phenylpropyl)-hexadecyl-ammonium tri-(4-trifluoromethylphenyl)hexylborate (example NEB3 in Table 2):

A photopolymer with N,N-dimethyl-N-(3-phenylpropyl)hexadecylammonium tri-(4-trifluoromethylphenyl)hexylborate as a coinitiator was prepared in accordance with the general manufacturing instructions for photopolymer films.

examples

The oxidation potential of various trialkyl aryl borates according to the invention and not according to the invention was calculated using the above-mentioned method for calculating the oxidation potential of triaryl alkyl borates using the GAMESS software package (G. MJ. Barca, C. Bertoni, L. Carrington, D. Datta, N. De Silva, JE Deustua, DG Fedorov, JR Gour, AO Gunina, E Guidez, T Harville, S Irle, J Ivanic, K Kowalski, SS Leang, H Li, WL, JJ Lutz, I Magoulas, Mato J, Mironov V, Nakata H, Pham BQ, Piecuch P, Poole D, Pruitt SR, Rendell AP, Roskop LB, Ruedenberg K, Sattasathuchana T, Schmidt MW, Shen J, L Slipchenko, M. Sosonkina, V. Sundriyal, A. Tiwari, JL Galvez Vallejo, JL Westheimer, B. Wloch, M., P. Xu, F. Zahariev, MS Gordon J Chem Phys 152 154102 (2020) .) calculated. The results of these calculations are listed in the table below. For the calculation of the oxidation potential, the cation of the corresponding trialkylaryl borate is irrelevant, so the values listed below apply to salts of the following general structure: (24), where K ⁺ or K ²⁺ stand for any ammonium or phosphonium cation.

Table 1. Oxidation potentials of various triarylalkylborate anions calculated according to formula (1), where the given radicals refer to the above general structure of formula (24) and the oxidation potential is given in V compared to the saturated calomel electrode in the solvent acetonitrile.

Table la .: According to formula (III) calculated oxidation potentials of various triaryl alkyl borate anions, where the specified radicals relate to formula (III) from claim 6 and the oxidation potential in [V] compared to the saturated calomel electrode in the solvent acetonitrile is given.

Evaluation of the thermal stability of the photopolymer films with co-initiators according to the invention:

The requirement for the photopolymer films created here is a low loss of performance

Photoactivity after a tempering step, ie that both the transmission of the Photopolymers after the tempering step must not increase critically and the diffraction efficiency must not decrease critically after the hologram exposure.

First, two samples were prepared identically for each example. The preparation involves first removing the liner of the photopolymer laminate and consequently laminating the resulting unprotected side of the photopolymer to a sheet of glass such that there is a glass-photopolymer substrate-lamina respectively. A transmission spectrum (T _1,RT ) was recorded directly from one of these samples, later referred to as the room temperature sample (RT), without temperature control. The second sample, later referred to as the tempering sample (Temp), was tempered in a drying cabinet at 110 °C for 10 min. After the tempering step, a transmission spectrum (Tijemp) 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 setup as described above. The quality of this hologram was evaluated using the difference in refractive index between exposed and unexposed areas (Δn) in the sample, which was derived from the diffraction efficiency read out. The thermal stability of a NIR light-sensitive photopolymer was evaluated based on two criteria that must be met. The two fulfillment criteria are therefore described in detail:

1. Thermostability 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 tempering step of the temp sample T _l,Temp,830 to the transmission of the RT sample at the same - chen wavelength T _l,RT,830 must be greater than 50%. The transmission values must be corrected for the background absorption caused by turbidity or similar (here the transmission at 1000 nm is used as a reference value) (T _{2, Temp, 1000} ):

2. Thermostability evaluated according to Δn: TS(Δn): The refractive index difference Δn of the Temp sample must be greater than 0.015:

TS(Δn) = Δn _Temp > 0.0150 (22)

The following transmission and Δn values of some examples according to the invention and not according to the invention were determined:

Table 2. Measured transmission and Δn values of the inventive and non-inventive examples, and the ratings calculated therefrom. Tl _,RT,830 : transmission of the RT sample at 830 nm; T _1,Temp,830 - transmission of the Temp sample at 830 nm, T _{2,Temp, 1000} - background transmission determined at 1000 nm; TS(T): evaluation of thermal stability after transmission loss; TS(Δn): Evaluation of thermal stability according to Δn.

* vs. SCE in acetonitrile; calculated; based on the triaryl alkyl borate used.

The results clearly show that the required thermal stability of a photopolymer can be achieved with the triarylalkyl borate 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

The use of all the borates listed in Table 1 as coinitiators in photopolymers therefore leads to heat-stable photopolymers in accordance with the objectives of this invention. It is also striking that the thermal stability of the photopolymer does not depend on the counter cation of the borate salt used, as a comparison of Examples 3a to 3d shows. A variation of the alkyl radical of the triarylalkyl borate salt is also possible without loss of the thermal stability of the photopolymer, as Examples 11, 38, 48 and 49 illustrate.

The non-inventive examples NEB1, NEB2 and NEB3 fail in at least one required property and are therefore unsuitable for providing a photopolymer composition with the required properties.

Claims

patent 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, free-radical stabilizers, solvents, additives and other auxiliaries and/or additives, the at least a photoinitiator system c) consists of at least one dye and at least one coinitiator, characterized in that at least one of the dyes has a structure according to formula (II). wherein R ²⁰⁵ is hydrogen, halogen, C ₁ - to C ₄ -alkyl, C ₁ - to C ₄ -alkoxy or NR ²¹⁰ R ²¹¹ , R ²⁰⁶ is hydrogen, halogen, C ₁ - to C ₄ -alkyl, C ₁ - to C ₄ -alkoxy or NR ²¹² R ²¹³ , R ²⁰¹ to R ²⁰⁴ and R ²¹⁰ to R ²¹³ are each independently hydrogen, C ₁ - to C ₁₆ - alkyl, C ₄ - to C ₇ -cycloalkyl, C ₇ - to C ₁₆ aralkyl, C ₆ to C ₁₀ aryl or a heterocyclic radical, NR ²⁰¹ R ²⁰² , NR ²⁰³ R ²⁰⁴ , NR ²¹⁰ R ²¹¹ and NR ²¹² R ²¹³ independently represent a five- or six-membered saturated ring attached via N, which may additionally contain an N or O and/or be substituted by nonionic radicals can be, R ²⁰⁷ to R ²⁰⁹ independently of one another are hydrogen, C ₁ - to C ₁₆ -alkyl, C ₄ - to C ₇ -cycloalkyl, C ₇ - to C ₁₆ -aralkyl, C ₆ - to C ₁₀ -aryl, halogen or Are cyano, the two optional bridging groups X ¹ and X ² are independently SiR ²¹⁴ R ²¹⁵ , CR ²¹⁶ R ²¹⁷ or O and R ²¹⁴ to R ²¹⁷ independently represent hydrogen or C ₁ - to C ₄ -alkyl and An for an anion selected from halide, perchlorate, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, tetraaryl borate, triarylalkyl borate, nitrate, cyanide, tosylate, trifluoromethyl sulfonate, bis(trifluoromethyl)sulfonimide, azide, methyl sulfonate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, hydrogen sulfate, an optionally substituted carboxylate, an optionally substituted organic mono- or di-sulfonate, or an optionally substituted organic mono- or di-carboxylate, and the at least one coinitiator has a calculated oxidation potential, 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 triaryl alkylborate after geometry optimization, consisting of conformer energy minimization using the AMI force field followed by an ab initio conformer energy calculation from the previously determined molecular geometry coordinates, in the solvent acetonitrile with solvent field correction according to the PCM method, in the range of 1.01 V to 1.31 V versus the saturated calomel electrode (SCE) in acetonitrile 2. The photopolymer composition according to any one of the preceding claims, wherein the at least one dye has a structure of formula (II), wherein R ²⁰⁵ is hydrogen, C ₁ - to C ₄ -alkyl, or NR ²¹⁰ R ²¹¹ , R ²⁰⁶ is hydrogen, C ₁ - to C ₄ -alkyl, or NR ²¹² R ²¹³ , R ²⁰¹ to R ²⁰⁴ and R ²¹⁰ to R ²¹³ are each independently hydrogen, methyl, ethyl, propyl, butyl, chloroethyl, cyanomethyl, cyanoethyl, methoxyethyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, benzyl, phenyl, tolyl, anisyl or chlorophenyl or NR ²⁰¹ R ²⁰² , NR ²⁰³ R ²⁰⁴ , NR ²¹⁰ R ²¹¹ and NR ²¹² R ²¹³ independently represent pyrrolidino, piperidino, morpholino or N-methylpiperazino, R ²⁰⁷ to R ²⁰⁹ are hydrogen and the two optional bridging groups X ¹ and X ² are independently SiMe ₂ or O. 3. The photopolymer composition according to any one of the preceding claims, wherein the at least one dye has a structure of the formula (XIX), wherein R ²⁰¹ to R ²⁰⁴ and R ²¹⁰ to R ²¹³ are each independently hydrogen or methyl, ethyl, propyl or butyl. 4. The photopolymer composition according to any one of the preceding claims, wherein the at least one present dye according to formula (II) or the formula (XIX) has an organically substituted sulfonate as anion (An-). 5. The photopolymer composition of any preceding claim, wherein the at least one coinitiator is a triaryl alkyl borate salt. 6. The photopolymer composition according to any one of the preceding claims, wherein the at least one coinitiator contains a triarylalkyl borate salt of formula (III), wherein A is a methylene group or any substituted methine group which can optionally form a ring with up to 10 members with R ¹⁰⁰ , R ¹⁰⁰ is hydrogen or a C ₁ - to C ₂₀ -alkyl, C 3 - to C 20 -alkenyl, C ₃ - to C _{20 -, optionally substituted by hydroxy and/or alkoxy and/or acyloxy and/or halogen, C 3 -} to C ₂₀ - alkynyl, C ₅ - to C ₇ -cycloalkyl or C ₇ - to C ₁₃ -aralkyl radical, R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ each represent up to five independently selected radicals from C ₁ - to C ₂₀ -alkyl-, C ₃ - to C ₅ -alkenyl-, C ₃ - to C ₅ -alkynyl-, C _{C 5} - to C ₇ -cycloalkyl or C ₇ - to C ₁₃ -aralkyl, halogen, cyano, trifluoromethyl, trichloromethyl, difluoromethyl, dichloromethyl, trifluoromethylthioyl, trichloromethylthioyl, C ₁ - to C ₁₂ -alkoxy, trifluoromethoxy, trichloromethoxy, C ₁ to C ₁₂ alkylthioyl, thioyl, difluoromethoxy, difluoromethylthioyl, carboxyl, carbonyl, 2-, 3-, or 4-pyridyl, or any substituted aryl residues or hydrogen, the selection of the residues being dependent on the calculated oxidation potential of the triarylalkyl borate (III) depending on the residues being in a range between 1.01 V vs. SCE and 1.31 V vs. SCE is in acetonitrile, K ⁺ is any substituted organocation of valence n based on nitrogen, phosphorus, oxygen, sulfur and/or iodine and n is 1, 2 or 3. 7. The photopolymer composition according to any one of the preceding claims, wherein R ¹⁰⁰ is a C ₁ - to C ₂₀ -alkyl, C ₅ - to C ₇ -cycloalkyl or C ₇ - to Cn-aralkyl radical and R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ are each one to two independently selected radicals from C ₁ - to C ₄ -alkyl, halogen, cyano, trifluoromethyl, C ₁ - to C ₄ -alkoxy or optionally substituted Aryl radicals or hydrogen. 8th . The photopolymer composition of any one of the preceding claims wherein R ¹⁰⁰ is C ₃ to C ₁₂ alkyl and R ¹⁰¹ , R ¹⁰² , and R ¹⁰³ are each one to two independently selected meta or para groups from C ₁ - to C ₄ -alkyl radicals and halogen substituents. 9. The photopolymer composition of any one of the preceding claims wherein the organocation K ⁺ of the triarylalkyl borate salt is a nitrogen- or phosphorus-based mono- or divalent cation, preferably is a nitrogen-based mono- or divalent cation, and most preferably is a monovalent ammonium cation. 10. The photopolymer composition according to any one of the preceding claims, wherein the at least one coinitiator has an oxidation potential between 1.01 V vs. SCE and 1.20 V vs. SCE in acetonitrile, preferably between 1.02 V and 1.17 V and especially preferably between 1.02 V and 1.15 V vs. SCE in acetonitrile. 1 1 . A layer structure containing at least the layers: A. a substrate layer A, which may be part of a further layer structure, B. a photopolymer layer B formed from the polymer composition according to any one of the preceding claims, and C. a cover layer C, which is optionally part of a further layer structure. 2 A layer structure containing at least the layers: 1 . A. a substrate layer A, which may be part of a further layer structure, B'. an exposed photopolymer layer B' produced from the photopolymer composition according to any one of claims 1 to 10 by photocuring, and C. a cover layer C, which is optionally part of a further layer structure. 13. Holographic medium containing a photopolymer composition according to any one of claims 1-10 or obtainable using a photopolymer composition according to any one of claims 1-10. 14. Holographic medium according to claim 13, characterized in that 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, preferably reflection, transmission or edge-lit hologram or a combination of at least two of these, combinations of these hologram types or several holograms of the same type can also be used independently of one another be combined in the same volume of the holographic medium (multiplexing). 15. An optical display comprising a holographic medium according to claim 13 or 14. 16. Use of a holographic medium according to claim 13 or 14 for the production of chip cards, identity documents, 3D images, product protection labels, labels, banknotes or holographically optical elements, in particular for optical displays or in media for the implementation of methods selected from the group consisting of Eye tracking, sensing, LIDAR, augmented reality, head-mounted display and virtual reality applications, particularly in the near infrared range and a combination of at least two of these. 17. Use of a photopolymer composition according to any one of claims 1 to 10 for the production of a holographic medium.