Photopolymer formulation for producing holographic media having highly crosslinked matrix polymers

1. A photopolymer formulation comprising a polyol component, a polyisocyanate component, a writing monomer and a photoinitiator containing a coinitiator and a dye of formula

F + An − ,

where

F + represents a cationic phenothiazine dye, and

An − represents an anion,

wherein the dye of formula F + An − has a water imbibition of ≦5%, and wherein the anion An− has an AClogP in the range of 1-6.5.

2. The photopolymer formulation according to claim 1 , wherein the dye has a water imbibition of ≦3%.

3. The photopolymer formulation according to claim 1 , wherein the dye has a water imbibition of ≦2%.

4. The photopolymer formulation according to claim 1 , wherein the anion An− has a molar mass >150 g/mol.

5. The photopolymer formulation according to claim 1 , wherein the anion An− has an AClogP in the range of 1-4 and the anion An− has a molar mass >250 g/mol.

6. The photopolymer formulation according to claim 1 , wherein the anion An− comprises at least a phosphorus, boron or sulphur atom.

7. The photopolymer formulation according to claim 1 , wherein the anion An− has one or more than one linear or branched aliphatic moiety or when it has more than one linear or branched aliphatic moiety, these together have 8 to 36 carbon atoms.

8. The photopolymer formulation according to claim 1 , wherein the anion An− is selected from the group C8- to C25-alkanesulphonate, C3- to C18-perfluoroalkanesulphonate, C9- to C25-alkanoate, C9- to C25-alkenoate, C8- to C25-alkyl sulphate, C8- to C25-alkenyl sulphate, preferably C13- to C25-alkenyl sulphate, C3- to C18-perfluoroalkyl sulphate, polyether sulphates based on 4 or more equivalents of ethylene oxide and/or propylene oxide, bis-C4- to C25-alkyl, C5- to C7-cycloalkyl, C3- to C8-alkenyl or C7- to C11-aralkyl sulphosuccinate, bis-C2- to C10-alkyl sulphosuccinate substituted by 8 or more fluorine atoms, C8- to C25-alkyl sulphoacetates, benzenesulphonate substituted by at least one moiety from the group halogen, C4- to C25-alkyl, perfluoro-C1- to C8-alkyl and/or C1- to C12-alkoxycarbonyl, optionally nitro-, cyano-, hydroxyl-, C1- to C25-alkyl-, C1- to C12-alkoxy-, amino-, C1- to C12-alkoxycarbonyl- or chlorine-substituted naphthalene- or biphenylsulphonate, optionally nitro-, cyano-, hydroxyl-, C1- to C25-alkyl-, C1- to C12-alkoxy-, C1- to C12-alkoxycarbonyl- or chlorine-substituted benzene-, naphthalene- or biphenyldisulphonate, dinitro-, C6- to C25-alkyl-, C4- to C12-alkoxycarbonyl-, benzoyl-, chlorobenzoyl- or toluoyl-substituted benzoate, the anion of naphthalenedicarboxylic acid, diphenyl ether disulphonate, sulphonated or sulphated, optionally mono- or polyunsaturated C8- to C25-fatty acid esters of aliphatic C1- to C8-alcohols or glycerol, bis(sulpho-C2- to C6-alkyl) C3- to C12-alkanedicarboxylic esters, bis(sulpho-C2- to C6-alkyl) itaconic acid esters, (sulpho-C2- to C6-alkyl) C6- to C18-alkanecarboxylic esters, (sulpho-C2- to C6-alkyl) acrylic or methacrylic acid esters, triscatechol phosphate optionally substituted by up to 12 halogen moieties, an anion from the group tetraphenyl borate, cyanotriphenyl borate, tetraphenoxyborate, C4- to C12-alkyltriphenyl borate, the phenyl or phenoxy moieties of which may be halogen, C1- to C4-alkyl and/or C1- to C4-alkoxy substituted, C4- to C12-alkyltrinaphthyl borate, tetra-C1- to C20-alkoxyborate, 7,8- or 7,9-dicarbanidoundecaborate(1-) or (2-), which optionally bear on the B and/or C atoms one or two C1- to C12-alkyl or phenyl substituents, dodecahydrodicarbadodecaborate(2-) or B—C1- to C12-alkyl-C-phenyldodecahydrodicarbadodecaborate(1-), where An− in multivalent anions and represents one equivalent of this anion, and where the alkane and alkyl groups may be branched and/or may be halogen, cyano, methoxy, ethoxy, methoxycarbonyl or ethoxycarbonyl substituted.

9. The photopolymer formulation according to claim 8 , where An− is naphthalenedisulphonate.

10. The photopolymer formulation according to claim 1 , wherein the anion An− is sec-C11- to C18-alkanesulphonate, C13- to C25-alkyl sulphate, branched C8- to C25-alkyl sulphate, optionally branched bis-C6- to C25-alkyl sulphosuccinate, sec- or tert-C4- to C25-alkylbenzenesulphonate, sulphonated or sulphated, optionally mono- or polyunsaturated C8- to C25-fatty acid esters of aliphatic C1- to C8-alcohols or glycerol, bis(sulpho-C2- to C6-alkyl) C3- to C12-alkanedicarboxylic esters, (sulpho-C2- to C6-alkyl) C6- to C18-alkanecarboxylic esters, triscatechol phosphate substituted by up to 12 halogen moieties, cyanotriphenyl borate, or tetraphenoxyborate.

11. The photopolymer formulation according to claim 1 , wherein the polyisocyanate component is an aliphatic polyisocyanate or a prepolymer with primary NCO groups.

12. The photopolymer formulation according to claim 1 , wherein the polyol component is a difunctional polyether, polyester or a polyether-polyester block copolyester with primary OH functions.

13. The photopolymer formulation according to claim 1 , wherein the writing monomer comprises at least a monofunctional and a multifunctional urethane(meth)acrylate.

14. The photopolymer formulation according to claim 1 , wherein it additionally comprises a plasticizer which conforms to general formula (CI)

where s is ≧1 and ≦8 and R 300 , R 301 , R 302 are independently of each other hydrogen, linear, branched, cyclic or heterocyclic unsubstituted or else optionally heteroatom-substituted organic moieties, wherein optionally at least one of R 300 , R 301 , R 302 is substituted with at least a fluorine atom and optionally R 300 is an organic moiety with at least one fluorine atom.

15. A holographic medium containing the photopolymer formulation according to claim 1 coated as a layer.

16. A process for recording of in-line, off-axis, full-aperture transfer, white light transmission, Denisyuk, off-axis reflection or edge-lit holograms or holographic stereograms, which comprises interferometrically exposing the holographic medium according to claim 15 .

17. The photopolymer formulation according to claim 1 , wherein a cured composition prepared from the photopolymer formulation has a plateau modulus G 0 which is greater than a plateau modulus G 0 obtained from the same composition comprising a dye which has a water imbibition of >5%, wherein the plateau modulus G 0 is determined by measuring the curing of the matrix in an oscillation rheometer as follows:

plate spacing 250 μm,

oscillation measuring mode at a constant angular frequency ω 0 of 10 rad/s and a controlled logarithmic deformation amplitude ramp of 1%

temperature 80° C., normal force regulation set at 0 Newton

recording of the storage modulus G′ over the measuring time for at least 2 hours or until a constant value of G′ was reached; this value is referred to as G 0 .