Film structure containing a photopolymer layer for holographic exposure and a coating layer of high resistance

Abstract

The invention relates to a layer construction comprising a curable protective layer C and a photopolymer layer B, to a method for producing such a layer construction, to a method for producing a hologram using such a layer construction, to a sealed holographic medium and to the use of such a layer construction for producing a hologram.

Claims

1. A Layer construction comprising a curable protective layer C and an areal photopolymer layer B comprising polyurethane matrix polymers, acrylate writing monomers and photoinitiators, which is at least partly joined to the protective layer C, wherein the protective layer C comprises I) at least one thermoplastic resin selected from the group consisting of polyvinylbutyral with M.sub.w≥100 000 g/mol or amorphous polymethyl methacrylate with M.sub.w≥100 000 g/mol; II) at least one reactive diluent selected from the group consisting of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, compound of formula (Ia) ##STR00055##  compound of formula (Ib) ##STR00056##  compound of formula (Ic) ##STR00057##  wherein in formulae (Ia) to (Ic)  R.sup.1 is independently at each occurrence a radiation-curable group and  X is independently at each occurrence a single bond between R.sup.1 and C═O or a linear, branched or cyclic optionally heteroatom-containing and/or optionally functional-group-substituted hydrocarbon radical,  compound of formula (II) ##STR00058##  wherein in formula (II)  R.sup.1 and X are as defined in formula (Ia)-(Ic),  R.sup.11 is a linear or branched, optionally heteroatom-substituted aliphatic, aromatic or araliphatic radical,  R.sup.12 is independently at each occurrence up to four sub stituents selected from methyl, ethyl, propyl, n-butyl, tert-butyl, chlorine, bromine, iodine, methylthio, phenyl and/or phenylthio,  R.sup.13 is independently at each occurrence up to five substituents selected from methyl, ethyl, propyl, n-butyl, tert-butyl, chlorine, bromine, iodine, methylthio, phenyl and/or phenylthio,  compound of formula (III) ##STR00059##  i) which is substituted at at least one of the carbon atoms 1, 2, 3, 4, 5, 6, 7, 8 with an R.sub.acryl radical of formula (IV), ##STR00060##  wherein in formula (IV)  R.sup.1 is as defined in formula (Ia)-(Ic),  R.sup.21 is oxygen or sulfur,  R.sup.22 is a carboxamide (—C(O)N—) or a carboxylic ester (—C(O)O—) or a sulfonamide (—SO.sub.2N—) group,  R.sup.23 is a saturated or unsaturated or linear or branched optionally substituted radical comprising 2-10 carbon atoms or a polyether comprising up to five (—CH.sub.2—CH.sub.2—O—)— or (—C(CH.sub.3)H—CH.sub.2—O—)— groups or a polyamine comprising up to five nitrogen atoms, and ii) the compound of formula (III) is at least one further carbon atom 1, 2, 3, 4, 5, 6, 7, 8 substituted with a radical of formula (V), ##STR00061##  wherein in formula (V)  the carbon atoms of the compound of formula (V) are each independently substituted with hydrogen, halogen, a cyano group, a nitro group or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aryl or heteroaryl group or an optionally substituted alkoxy or alkylthio group or any substituted carbamoyl group, which also may be linked bridgingly to a radical of formula (III), or a trifluoromethyl group or a trifluoromethoxy group or an R.sub.acryl′ radical of formula (VI), ##STR00062##  wherein in formula (VI)  R.sup.1′ has the same definition as R.sup.1 in formula (IV),  R.sup.21 ′ is oxygen or sulfur,  R.sup.22′ is a carboxamide (—C(O)N—) or a carboxylic ester (—C(O)O—) or a sulfonamide (—SO2N—) group,  R.sup.23′ is a saturated or unsaturated or linear or branched optionally substituted radical comprising 2-10 carbon atoms or a polyether comprising up to five (—CH.sub.2—CH.sub.2—O—)— or (—C(CH.sub.3)H—CH.sub.2—O—)— groups or a polyamine comprising up to five nitrogen atoms, iii) the remaining carbon atoms of the compound of formula (III) are each independently substituted with hydrogen, halogen, a cyano group, a nitro group or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aryl or heteroaryl group or an optionally substituted alkoxy or alkylthio group or a trifluoromethyl group or a trifluoromethoxy group, and compound of formula (VII) ##STR00063##  wherein in formula (VII) R.sup.31, R.sup.32, R.sup.33 are each independently of one another OH, halogen or an organic radical, wherein at least one of the radicals is an organic radical comprising a radiation-curable group; and III) comprises at least one photoinitiator.

2. The layer construction according to claim 1, wherein the photopolymer layer B is disposed on a substrate layer A, wherein the photopolymer layer B is on one side at least partly joined to the substrate layer A and the photopolymer layer B is on the other side at least partly joined to the protective layer C.

3. The layer construction according to claim 1, wherein the protective layer C is disposed on a substrate layer D, wherein the protective layer C is on one side at least partly joined to the substrate layer D and the protective layer C is on the other side at least partly joined to the photopolymer layer B.

4. The layer construction according to claim 1, wherein the layer construction consists of at least four layers at least partly joined to one another, wherein the layers are arranged directly atop one another in the sequence substrate layer A, photopolymer layer B, protective layer C and substrate layer D.

5. The layer construction according to claim 1, wherein the reactive diluent is pentaerythritol triacrylate, a compound of formulae (Ia), (Ib), (Ic), (II), (III), (VII) and/or mixtures thereof.

6. The layer construction according to claim 1, wherein the protective layer C has a thickness of 1 to 100 μm.

7. The layer construction according to claim 1, wherein the protective layer C further contains a UV absorber.

8. A process for producing a layer construction according to claim 1, wherein atop a photopolymer layer B a protective layer C is applied wherein the protective layer C comprises I) at least one thermoplastic resin selected from the group consisting of polyvinylbutyral with M.sub.w≥100 000 g/mol or amorphous polymethyl methacrylate with M.sub.w≥100 000 g/mol; II) at least one reactive diluent selected from the group consisting of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, compound of formula (Ia) ##STR00064##  compound of formula (Ib) ##STR00065##  compound of formula (Ic) ##STR00066##  wherein in formulae (Ia) to (Ic)  R.sup.1 is independently at each occurrence a radiation-curable group and  X is independently at each occurrence a single bond between R.sup.1 and C═O or a linear, branched or cyclic optionally heteroatom-containing and/or optionally functional-group-substituted hydrocarbon radical,  compound of formula (II) ##STR00067##  wherein in formula (II)  R.sup.1 and X are as defined in formula (Ia)-(Ic),  R.sup.11 is a linear or branched, optionally heteroatom-substituted aliphatic, aromatic or araliphatic radical,  R.sup.12 is independently at each occurrence up to four sub stituents selected from methyl, ethyl, propyl, n-butyl, tert-butyl, chlorine, bromine, iodine, methylthio, phenyl and/or phenylthio,  R.sup.13 is independently at each occurrence up to five substituents selected from methyl, ethyl, propyl, n-butyl, tert-butyl, chlorine, bromine, iodine, methylthio, phenyl and/or phenylthio,  compound of formula (III) ##STR00068##  i) which is substituted at at least one of the carbon atoms 1, 2, 3, 4, 5, 6, 7, 8 with an R.sub.acryl radical of formula (IV), ##STR00069##  wherein in formula (IV)  R.sup.1 is as defined in formula (Ia)-(Ic),  R.sup.21 is oxygen or sulfur,  R.sup.22 is a carboxamide (—C(O)N—) or a carboxylic ester (—C(O)—) or a sulfonamide (—SO.sub.2N—) group,  R.sup.23 is a saturated or unsaturated or linear or branched optionally substituted radical comprising 2-10 carbon atoms or a polyether comprising up to five (—CH.sub.2—CH.sub.2—O—)— or (—C(CH.sub.3)H—CH.sub.2—O—)— groups or a polyamine comprising up to five nitrogen atoms, and ii) the compound of formula (III) is at least one further carbon atom 1, 2, 3, 4, 5, 6, 7, 8 substituted with a radical of formula (V), ##STR00070##  wherein in formula (V)  the carbon atoms of the compound of formula (V) are each independently substituted with hydrogen, halogen, a cyano group, a nitro group or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aryl or heteroaryl group or an optionally substituted alkoxy or alkylthio group or any substituted carbamoyl group, which also may be linked bridgingly to a radical of formula (III), or a trifluoromethyl group or a trifluoromethoxy group or an R.sub.acryl′ radical of formula (VI), ##STR00071##  wherein in formula (VI)  R.sup.1′ has the same definition as R.sup.1 in formula (IV),  R21′ is oxygen or sulfur,  R22′ is a carboxamide (—C(O)N—) or a carboxylic ester (—C(O)O—) or a sulfonamide (—SO.sub.2N—) group,  R.sup.23′ is a saturated or unsaturated or linear or branched optionally substituted radical comprising 2-10 carbon atoms or a polyether comprising up to five (—CH.sub.2—CH.sub.2—O—)— or (—C(CH.sub.3)H—CH.sub.2—O—)— groups or a polyamine comprising up to five nitrogen atoms, iii) the remaining carbon atoms of the compound of formula (III) are each independently substituted with hydrogen, halogen, a cyano group, a nitro group or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aryl or heteroaryl group or an optionally substituted alkoxy or alkylthio group or a trifluoromethyl group or a trifluoromethoxy group, and compound of formula (VII) ##STR00072##  wherein in formula (VII)  R.sup.31, R.sup.32, R.sup.33 are each independently of one another OH, halogen or an organic radical, wherein at least one of the radicals is an organic radical comprising a radiation-curable group; and III) comprises at least one photoinitiator.

9. The process according to claim 8, wherein in a first step the photopolymer layer B is applied atop a substrate layer A to afford a layer composite A-B, in a second step the protective layer C is applied atop a substrate layer D to afford a layer composite C-D and in a third step the layer composite A-B is areally joined to the layer composite C-D to obtain a layer composite A-B-C-D, wherein the layer composite A-B is joined to the layer composite C-D by lamination.

10. A process for producing a hologram comprising the steps of: a) providing a multilayer recording material containing a layer composite A-B-C-D comprising I) a substrate layer A, II) a photopolymer layer B comprising polyurethane matrix polymers, acrylate writing monomers and photoinitiators; III) a protective layer C, comprising IIIa) at least one thermoplastic resin selected from the group consisting of polyvinylbutyral with Mw≥100 000 g/mol or amorphous polymethyl methacrylate with Mw≥100 000 g/mol; IIIb) at least one reactive diluent selected from the group consisting of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, compound of formula (Ia) ##STR00073##  compound of formula (Ib) ##STR00074##  compound of formula (Ic) ##STR00075##  wherein in formulae (Ia) to (Ic)  R.sup.1 is independently at each occurrence a radiation-curable group and  X is independently at each occurrence a single bond between R.sup.1 and C═O or a linear, branched or cyclic optionally heteroatom-containing and/or optionally functional-group-substituted hydrocarbon radical,  compound of formula (II) ##STR00076##  wherein in formula (II)  R.sup.1 and X are as defined in formula (Ia)-(Ic),  R.sup.11 is a linear or branched, optionally heteroatom-substituted aliphatic, aromatic or araliphatic radical,  R.sup.12 is independently at each occurrence up to four substituents selected from methyl, ethyl, propyl, n-butyl, tert-butyl, chlorine, bromine, iodine, methylthio, phenyl and/or phenylthio,  R.sup.13 is independently at each occurrence up to five substituents selected from methyl, ethyl, propyl, n-butyl, tert-butyl, chlorine, bromine, iodine, methylthio, phenyl and/or phenylthio,  compound of formula (III) ##STR00077##  i) which is substituted at least one of the carbon atoms 1, 2, 3, 4, 5, 6, 7, 8 with an R.sub.acryl radical of formula (IV), ##STR00078##  wherein in formula (IV)  R.sup.1 is as defined in formula (Ia)-(Ic),  R.sup.21 is oxygen or sulfur,  R.sup.22 is a carboxamide (—C(O)N—) or a carboxylic ester (—C(O)O—) or a sulfonamide (—SO.sub.2N—) group,  R.sup.23 is a saturated or unsaturated or linear or branched optionally substituted radical comprising 2-10 carbon atoms or a polyether comprising up to five (—CH.sub.2—CH.sub.2—O—)— or (—C(CH.sub.3)H—CH.sub.2—O—)— groups or a polyamine comprising up to five nitrogen atoms, and  ii) the compound of formula (III) is at least one further carbon atom 1, 2, 3, 4, 5, 6, 7, 8 substituted with a radical of formula (V), ##STR00079##  wherein in formula (V)  the carbon atoms of the compound of formula (V) are each independently substituted with hydrogen, halogen, a cyano group, a nitro group or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aryl or heteroaryl group or an optionally substituted alkoxy or alkylthio group or any substituted carbamoyl group, which also may be linked bridgingly to a radical of formula (III), or a trifluoromethyl group or a trifluoromethoxy group or an R.sub.acryl′ radical of formula (VI), ##STR00080##  wherein in formula (VI)  R.sup.1′ has the same definition as R.sup.1 in formula (IV),  R.sup.21′ is oxygen or sulfur,  R.sup.22′ is a carboxamide (—C(O)N—) or a carboxylic ester (—C(O)O—) or a sulfonamide (—SO.sub.2N—) group,  R.sup.23′ is a saturated or unsaturated or linear or branched optionally substituted radical comprising 2-10 carbon atoms or a polyether comprising up to five (—CH.sub.2—CH.sub.2—O—)— or (—C(CH.sub.3)H—CH.sub.2—O—)— groups or a polyamine comprising up to five nitrogen atoms, iii) the remaining carbon atoms of the compound of formula (III) are each independently substituted with hydrogen, halogen, a cyano group, a nitro group or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aryl or heteroaryl group or an optionally substituted alkoxy or alkylthio group or a trifluoromethyl group or a trifluoromethoxy group, and compound of formula (VII) ##STR00081##  wherein in formula (VII)  R.sup.31, R.sup.32, R.sup.33 are each independently of one another OH, halogen or an organic radical, wherein at least one of the radicals is an organic radical comprising a radiation-curable group; and IIIc) comprises at least one photoinitiator, and IV) a substrate layer D, wherein the layers in the sequence substrate layer A, photopolymer layer B, protective layer C and substrate layer D are arranged directly atop one another; b) photoinscribing a hologram into the photopolymer layer B to form a layer composite A-B*-C-D, wherein B* is a photopolymer layer with an inscribed hologram; c) subjecting the layer composite A-B*-C-D from step (b) to actinic radiation, to form a layer composite A-B′-C′-D, wherein B′ is the bleached, through-polymerized and no-longer-photosensitive photopolymer layer B comprising a fixed hologram and C′ is the cured protective layer C; and d) delaminating the substrate layer D of the layer composite A-B′-C′-D from step (c) to form a layer composite A-B′-C′.

11. A sealed holographic medium comprising a layer construction A-B′-C′ obtained by the process according to claim 10.

12. An optical display comprising the sealed holographic medium according to claim 11, wherein the optical display is selected from the group consisting of autostereoscopic and/or holographic displays, projection screens, displays with switchable restricted emission characteristics for privacy filters and bidirectional multiuser screens, virtual displays, head-up displays, head-mounted displays, illumination symbols, warning lamps, signal lamps, floodlights/headlights and display panels.

13. A security document comprising the sealed holographic medium according to claim 11.

14. A method comprising utilizing the layer construction according to claim 1 comprising exposing the layer and thereby producing holograms selected from the group consisting of in-line holograms, off-axis holograms, full-aperture transfer holograms, white light transmission holograms, Denisyuk holograms, off-axis reflection holograms, edge-lit holograms and holographic stereograms.

Description

EXAMPLES

(1) The present invention shall hereinbelow be described in more detail via the following drawings and examples.

(2) Test Methods:

(3) Solids content: The reported solids contents were determined according to DIN EN ISO 3251.
Chemicals:

(4) In each case, the CAS number, if known, is reported in square brackets.

(5) Raw Materials for Photopolymer Layer B

(6) Fomrez® UL 28 Urethanization catalyst, commercial product of Momentive Performance Chemicals, Wilton, Conn., USA. Borchi® Kat 22 Urethanization catalyst, [85203-81-2] commercial product of OMG Borchers GmbH, Langenfeld, Germany. BYK-310 Silicone-containing surface additive, product of BYK-Chemie GmbH, Wesel, Germany. Desmodur® N 3900 Product of Covestro AG, Leverkusen, DE, hexane diisocyanate-based polyisocyanate, proportion of iminooxadiazinedione of at least 30%, NCO content: 23.5%. CGI-909 Tetrabutylammonium tris(3-chloro-4-methylphenyl)-(hexyl)borate, [1147315-11-4], product of BASF SE.

(7) Dye 1 (3,7-bis(diethylamino)phenoxazin-5-ium bis(2-ethylhexyl)sulfosuccinate) was prepared as described in WO 2012062655.

(8) Polyol 1 was produced as described in WO2015091427.

(9) Urethane acrylate 1 simultaneously also RD 2, (phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisacrylate, [1072454-85-3]) was produced as described in WO2015091427.

(10) Urethane acrylate 2, (2-({[3-(methylsulfanyl)phenyl]carbamoyl}oxy)ethyl prop-2-enoate, [1207339-61-4]) was produced as described in WO2015091427.

(11) 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 produced as described in WO2015091427.

(12) Raw Materials of Protective Layer C

(13) Physically Drying Resins

(14) Mowital B75H—Resin 1 A linear thermoplastic, amorphous polyvinyl butyral having an M.sub.w of 240 000 from Kuraray Europe GmbH, Hattersheim, Germany Degacryl M547—Resin 2 A linear thermoplastic, amorphous polymethyl methacrylate having an M.sub.w of 500000 from Evonik Industries, Marl, Germany Desmocoll 400/3—resin 3 A linear thermoplastic flexible polyurethane from Covestro Deutschland AG, Leverkusen, Germany. Mowital B30HH—resin 4 A linear thermoplastic amorphous polyvinylbutyral having a Mw of 80 000-90 000 from Kuraray Europe GmbH, Hattersheim, Germany, Pioloform BL 16—resin 5 A linear thermoplastic amorphous, low-viscosity mixed polyvinylacetal, produced from polyvinyl alcohol with butyraldehyde and acetaldehyde having a Mw of 50 000-60 000 from Kuraray Europe GmbH, Hattersheim, Germany,
Acryloyl-Functional Reactive Diluents (RD) Sartomer SR444D—RV 1 [3524-68-3] Pentaerythritol triacrylate (PETIA) from SARTOMER Division of CRAY VALLEY, Paris, France (Arkema Group). RD 2 (Phosphorothioyltris(oxybenzene-4,1-diylcarbamoyloxyethane-2,1-diyl) trisacrylate, [1072454-85-3]) produced as described in WO2015091427. Miramer M410—RD 3 [94108-97-1] Ditrimethylolpropane tetraacrylate from Miwon Specialty Chemical Co., Ltd., Gyeonggi-do, Korea. Sartomer SR494—RD 4 Quadruply ethoxylated pentaerythritol tetraacrylate (PPTTA) from SARTOMER division of CRAY VALLEY, Paris, France (Arkema Group). Ebecryl 8465—RD 5 An aliphatic urethane triacrylate oligomer from Allnex, Brussels, Belgium.
Photoinitiators Esacure One—Initiator 1 [163702-01-0] Oligo[2-hydroxy-2-methyl-1-((4-(1-methylvinyl)phenyl)propanone] from Lamberti S.p.A., Albizzate, Italy Irgacure 4265—Initiator 2 A mixture of Irgacure® TPO (50% by weight) and Irgacure® 1173 (50% by weight) from BASF, SE, Ludwigshafen, Germany.
Additives BYK 333 Silicone-containing surface additive from BYK Chemie GmbH, Wesel, Germany
Solvent Butyl acetate (BA) Butyl acetate from Brenntag GmbH, Mülheim an der Ruhr, Germany. Methoxypropanol (MP-ol) 1-Methoxy-2-propanol from Brenntag GmbH, Mülheim an der Ruhr, Germany.
Production of Holographic Media (Photopolymer Film)

(15) 7.90 g of the above-described polyol component were melted and mixed with 7.65 g of the respective urethane acrylate 2, 2.57 g of the above-described urethane acrylate 1, 5.10 g of the above-described fluorinated urethane (additive 1), 0.91 g of CGI 909, 0.232 g of dye 1, 0.230 g of BYK 310, 0.128 g of Fomrez UL 28 and 3.789 g of ethyl acetate to obtain a clear solution. 1.50 g of Desmodur® N 3900 were then added and the mixture was mixed again.

(16) This solution was then applied to a PET film of 36 μm in thickness in a roll-to-roll coating plant where by means of a knife coater the product was applied in a wet film thickness of 19 μm. At a drying temperature of 85° C. and a drying time of 5 minutes the coated film was dried and subsequently protected with a polyethylene film of 40 μm in thickness. This film was then light-tightly packaged.

(17) Production of the Latent Protective Layer C on Substrate D

(18) The formulations reported in table 1 were produced by mixing the physically drying resins, dissolved at 100° C. in the reported organic solvent and cooled to room temperature, with the reactive diluent. The photoinitiators and also flow control agents were then added in darkness.

(19) TABLE-US-00001 TABLE 1 Coating compositions* for production of the latent protective layer C Weight of Solids content Viscosity ratio of resin (% by weight) of lacquer to RD in and solvent of at 23° C. Resin RD lacquer coating solution [mPas] Inventive examples 01 Resin RD 1 50/50 20% in MP-ol 4400 1 02 Resin RD 2 20/80 28% in MP-ol 950 1 03 Resin RD 2 20/80 28% in MP-ol 111 2 Noninventive examples N 01 Resin RD 2 40/60 26% in butyl 1120 3 acetate N 02 Resin RD 3 50/50 25% in butyl 2220 3 acetate N 03 Resin RD 4 50/50 25% in butyl 2100 3 acetate N 04 Resin RD 4 25/75 25% in MP-ol 169 2 N 05 Resin RD 3 20/80 28% in MP-ol 82 2 N 06 Resin RD 5 20/80 28% in MP-ol 278 2 N 07 Resin RD 2 20/80 30% in MP-ol 91 4 N08 Resin RD 2 20/80 35% in MP-al 98 5 *All coating compositions contain initiator 1 (3% by weight based on solids content of lacquer), initiator 2 (1.5% by weight based on solids content of lacquer) and flow control agent (0.2% by weight based on solids content of lacquer)

(20) The lacquers produced as described hereinabove were applied atop a PET film of 36 μm in thickness (RNK 36 from Mitsubishi Polyester Film GmbH, Wiesbaden, Germany) in a roll-to-roll coating plant by means of a knife coater. At a drying temperature of 85° C. and a drying time of 5 minutes the coated film was dried and subsequently protected with a polyethylene film of 40 μm in thickness. The coating thickness was generally 15-16 μm. This film was then light-tightly packaged.

(21) Production of a Light-Sensitive Film Composite Having the Layer Construction A-B-C-D

(22) The production of a light-sensitive film having the layer construction A-B-C-D suitable for the inscribing of holograms includes initially laminating side B of the layer composite A-B onto side C of the layer composite C-D. This is effected in the absence of light by pressing together the two films between the rubber rollers of a laminator. The temperature T.sub.Lam of the rollers was preset to 30° C., 60° C. or 90° C. The thus obtained laminate must be stored under protection from light.

(23) Production of Test Holograms in the Layer Construction A-B-C-D

(24) The test holograms for assessment of the layer construction A-B-C-D were prepared as follows: the photopolymer films with the layer construction A-B-C-D, and also the comparative photopolymer films with the layer construction A-B, were in darkness cut to the desired size and using a rubber roller laminated onto a glass sheet having dimensions of 50 mm×70 mm (3 mm thick). The test holograms were produced using a test apparatus which produces Denisyuk reflection holograms using 532 nm laser radiation. The test apparatus consists of a laser source, an optical beam guide system and a holder for the glass coupons. The holder for the glass coupons is mounted at an angle of 13° relative to the beam axis. The laser source generates the radiation which, widened to about 5 cm by means of a specific optical beam path, is guided to the glass coupon in optical contact with the mirror. The holographed object was a mirror about 2 cm×2 cm in size, and so the wavefront of the mirror was reconstructed on reconstructing the hologram. All examples were irradiated with a green 532 nm laser (Newport Corp., Irvine, Calif., USA, cat. no. EXLSR-532-50-CDRH). A shutter was used to irradiate the recording film in a defined manner for 2 seconds. This affords a film composite A-B*-C-D with a hologram in the layer B (exception—noninventive example N 05 where no hologram was formed).

(25) The samples were subsequently placed onto the conveyor belt of a UV source with the substrate side D facing the lamp and exposed twice at a belt speed of 2.5 m/min. The UV source employed was a Fusion UV “D Bulb” No. 558434 KR 85 iron-doped Hg lamp having a total power density of 80 W/cm.sup.2. The parameters correspond to a dose of 2× about 2.0 J/cm.sup.2 (measured with an ILT 490 Light Bug). After this fixing step the film composite A-B′-C′-D is formed from which the carrier film D was removed.

(26) Table 2 (columns “adhesion of C′-B′ in the process” and “removability of film D”) shows the results of this step for all tested layer constructions. All inventive protective layers (01 to 02) show a good adhesion in the inventive process of producing the film composites A-B-C-D, A-B*-C-D and A-B′-C′-D. The following step, removal of film D for producing the layer construction A-B′-C′, is likewise performable in all inventive examples. Even the noninventive compositions N 01 to N 06 are processable in this way. By contrast, the noninventive compositions N 07 and N 08 produced with the low molecular weight resins 4 and 5 do not exhibit adhesion sufficient for the abovementioned reduction process.

(27) Characterization of Protective Layer C′

(28) Quantitative Analysis of Adhesion of Protective Layer C′ on Layer B′ of the Holographic Film A-B′ According to ISO 2409:2013-02 (E)(Crosscut Test):

(29) Adhesive tape pull-off (adhesive tape employed: 3M Scotch 898) with crosscut (as per ISO 2409:2013-02 (E)) was performed. Performance values vary from full adhesion (ISO performance value: 0) to inadequate (according to ISO 2409:2013-02 (E)) adhesion (ISO performance value: 5).

(30) Assessment of Solvent Resistance

(31) The solvent resistance of the coatings was typically tested with technical quality N-ethyl-2-pyrrolidone (NEP), methyl ethyl ketone (MEK), 1-butanol and ethyl acetate (EA). The solvents were applied to the coating with a cotton bud and protected from evaporation by covering. Unless otherwise stated, a contact time of 60 minutes at about 23° C. was observed. Once the contact time has elapsed, the cotton bud is removed and the test surface is wiped clean with a soft cloth. This is followed by visual inspection immediately and after light scratching with a fingernail.

(32) A distinction is made between the following levels: 0=unchanged; no change visible; not damageable by scratching. 1=slight swelling visible, but not damageable by scratching. 2=change clearly visible, barely damageable by scratching. 3=noticeable change, surface destroyed after firm fingernail pressure. 4=severe change, scratched through to substrate after firm fingernail pressure. 5=destroyed; lacquer already destroyed on wiping off the chemical; the test substance is not removable (eaten into surface).

(33) Within this assessment, the test is typically passed with performance values of 0 and 1. Performance values of >1 represent a “fail”. The results are summarized in table 2. All inventive coatings C′ made of lacquers 01 to 03 have a very high degree of solvent resistance. By contrast, the layers C′ made of the noninventive compositions N 01 to N 03 and N 06 show insufficient solvent resistance. The layers made of compositions N 04 and N 05 do pass the solvent test but in their latent (not UV cured) form have such a strong effect on the photosensitivity of layer B that said layer consequently becomes unusable as an optical recording material (table 3).

(34) Characterization of Test Holograms

(35) The holograms in layer B′ of film composite A-B′-C′ produced by the inventive process for producing holograms were then subjected to quality analysis by spectroscopy.

(36) On account of the high diffraction efficiency of the volume hologram, the diffractive reflection of such holograms may be analysed in transmission with visible light with a spectrometer (USB 2000 instrument, Ocean Optics, Dunedin, Fla., USA, is employed) and appears in the transmission spectrum as a peak with reduced transmission. Evaluating the transmission curve makes it possible to determine the quality of the hologram according to ISO standard 17901-1:2015(E) taking account of the following measured values; all results from the inventive and noninventive examples are summarized in table 3:

(37) TABLE-US-00002 FWHM The width of the transmission peak is determined as “full width at half maximum” (FWHM) in nanometres (nm). T.sub.Red = 100-T.sub.peak (1) Maximum depth of the transmission peak, this corresponds to the (A-B’-C’) highest diffraction efficiency. Thus, 100-T.sub.peak(A-B’-C’) serves as a measure for the reflection power (or visible “strength” or “quality”) of the hologram. ΔT Calculated difference in maximum depth of the transmission peak of the hologram in layer construction A-B’-C’ compared to layer construction A- B’ as: ΔT = (100% − T.sub.peak(A-B’-C’)%) − (100% − T.sub.peak(A-B’)%) (2) λ.sub.peak Spectral position of the transmission minimum of the hologram in nanometres (nm). Δλ Difference in transmission minima in layer construction A-B’-C’ compared to λ.sub.w of the writing laser as: Δλ = λ.sub.peak − λ.sub.w (3)

(38) For the noninventive sample V 1 as a point of reference for the layer construction A-B′ the transmission is 91%, the FWHM is at 25 nm and the transmission minimum is at 527 nm.

(39) It is an essential feature of the invention that the optical performance values FWHM, 100-T.sub.min(A-B′-C′) and λ.sub.peak in the construction A-B′-C′ deviate from these optical performance values in the construction A-B only very slightly, if at all. According to the invention the reduction in transmission (T.sub.Red %) for construction A-B-C-D is therefore 0 to 20%, preferably from 0 to 10%, lower than for construction A-B (sample V 1 in table 3). For the inventive samples from 01-1 to 03-2 the T.sub.Red values are between 76% and 90% and therefore deviate only by −1% to −5% on the transmission scale with respect to sample V 1. The values remain unchanged even after storage at room temperature for 3 days.

(40) The layers C made of the noninventive compositions N 01 to N 06 in their latent (not UV-cured) form have such a strong effect on the photosensitivity of layer B that said layer shows remarkable weakness as an optical recording material. The T.sub.Red values of the holograms recorded therein are substantially lower. In the case of N 05 no hologram whatsoever can be recorded.

(41) A further aspect of the quality of the holograms relates to λ.sub.peak. For application of the holographic materials in demanding optical functions it is enormously important that λ.sub.peak of the inscribed hologram deviates from λ.sub.w of the writing laser to the smallest possible extent. It is preferable when Δλ is +/−10 nm, more preferably +/−5 nm, particularly preferably +/−3 nm.

(42) As is shown in table 3 Δλ of the comparative sample V 1 is −5 nm. In this context the inventive samples are at least no poorer and in most cases are in fact more advantageous. Their deviation from Δλ is 0 to 5 nm. The noninventive samples deviate markedly more severely.

(43) TABLE-US-00003 TABLE 2 Transferability of the protective layer C onto the holographic film A-B and protective quality of coatings C′ Solvent resist- C′-B′ ance (1 h) of adhesion Remov- C′-B′ C′ against Layer T.sub.Lam. in the ability of adhesion NEP/MEK/ C Sample [° C.] process film D (crosscut) butanol/EA none.sup.# V 1 — — — — 5/5/1/5 (after 10 min) Inventive examples 01 01-1 30 + + 2 0/0/0/0 01 01-2 30 + + 3 0/0/0/0 01 01-3 60 + + 2 0/0/0/0 01 01-4 60 + + 4 0/0/0/0 01 01-5 90 + + 2 0/0/0/0 02 02-1 30 + + 0 0/0/0/0 02 02-2 30 + + 0 0/0/0/0 02 02-3 60 + + 1 0/0/0/0 02 02-4 60 + + 0 0/0/0/0 02 02-5 90 + + 0 0/0/0/0 03 03-1 30 + + 5 0/0/0/0 03 03-2 30 + + 5 0/0/0/0 Noninventive examples N 01 N 01-1 60 + + 0 4/4/4/4 N 02 N 02-1 60 + + 0 4/4/4/4 N 03 N 03-1 30 + + 3 5/5/4/5 N 04 N 04-1 30 + + 5 0/1/0/0 N 05 N 05.1 30 + + 5 0/0/0/0 N 06 N 06-1 30 + + 0 5/5/4/5 N 07 N 07-1 30 − Assessment not possible, no adhesion A-B′-C′-D N 07 N 07-2 60 − Assessment not possible, no adhesion A-B′-C′-D N 07 N 07-3 90 − Assessment not possible, no adhesion A-B′-C′-D N 08 N 08-1 30 − Assessment not possible, no adhesion A-B′-C′-D N 08 N 08-2 60 − Assessment not possible, no adhesion A-B′-C′-D N 08 N 08-3 90 − Assessment not possible, no adhesion A-B′-C′-D .sup.#reference sample

(44) TABLE-US-00004 TABLE 3 Characterization of test holograms after a) inscription into the A-B-C-D film composite, b) fixing by UV-VIS of ~4 J/cm.sup.2. Assessment is of the film composite A-B′-C′ obtained from A-B′-C′-D by removal of D Characterization of test holograms 1 h after application of protective layer 3 days after application of protective layer 100-T.sub.peak 100-T.sub.peak Layer T.sub.Lam. (A-B′-C′) ΔT FWHM λ.sub.peak Δλ (A-B′-C′) ΔT FWHM λ.sub.peak Δλ C Sample [° C.] [%] [%] [nm] [nm] [nm] [%] [%] [nm] [nm] [nm] none.sup.# V 1 —   91** — 25 527 −5 Inventive examples 01 01-1 30 76 −15 22 530 −2 76 −15 22 529 −3 01 01-2 30 81 −10 23 530 −2 85 −6 22 529 −3 01 01-3 60 83 −8 18 528 −4 81 −10 18 527 −5 01 01-4 60 84 −7 24 530 −2 84 −7 22 529 −3 01 01-5 90 83 −8 16 529 −3 83 −8 16 528 −4 02 02-1 30 83 −8 17 527 −5 86 −5 17 527 −5 02 02-2 30 88 −3 19 529 −3 87 −4 19 530 −2 02 02-3 60 83 −8 16 530 −2 81 −10 15 530 −2 02 02-4 60 90 −1 19 529 −3 90 −1 19 529 −3 02 02-5 90 83 −8 16 528 −4 83 −8 16 528 −4 03 03-1 30 80 −11 15 532 0 82 −9 15 533 +1 03 03-2 30 85 −6 17 533 +1 84 −7 16 534 +2 Noninventive examples N 01 N01-1 60 70 −21 15 536 +4 78 −13 15 537 +5 N 02 N02-1 60 25 −66 13 529 −3 — — — — — N 03 N03-1 30 67 −24 17 534 +2 56 −35 15 523 −9 N 04 N04-1 30 41 −50 11 545 +13 39 −52 11 544 +12 N 05 N05-1 30 * * N 06 N06-1 30 29 −62 13 560 +28 23 −68 14 559 +27 .sup.#reference sample; *hologram not inscribable; **measured in layer construction A-B′