Photopolymer formulation for production of holographic media comprising borates with low TG

Patent metadata

Field	Value
Publication number	US-10001703-B2
Application number	US-201415029080-A
Country	US
Kind code	B2
Filing date	Oct 13, 2014
Priority date	Oct 17, 2013
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

The invention relates to a photopolymer formulation comprising a component reactive toward isocyanates, a polyisocyanate component, a writing monomer and a photoinitiator containing at least one dye and a coinitiator, characterized in that the coinitiator contains at least one substance of the formula (Ia)

The invention further provides a process for preparing the specific coinitiators and the coinitiators obtainable by this process, and additionally a process for producing a holographic medium using the specific coinitiators, and a holographic medium obtainable using the inventive photopolymer formulation. The invention further relates to a laminate structure comprising an inventive holographic medium and likewise specific borates suitable as coinitiators.

First claim

The invention claimed is:

1. A photopolymer formulation comprising a component reactive toward isocyanates, a polyisocyanate component, a writing monomer and a photoinitiator consisting essentially of at least one dye and a coinitiator, wherein the coinitiator consists essentially of at least one substance of the formula (Ia)

in which
R 1 is an optionally branched C 14 - to C 22 -alkyl radical,
R 2 is an optionally branched and/or optionally substituted C 8 - to C 22 -alkyl radical, a cyclohexyl or cycloheptyl radical, a C 7 - to C 10 -aralkyl radical, or a phenyl radical substituted by nonionic radicals, and
R 3 and R 4 are each independently an optionally branched and/or optionally substituted C 1 - to C 5 -alkyl radical or
R 1 is an optionally branched C 14 - to C 22 -alkyl radical,
R 2 is an optionally branched and/or optionally substituted C 8 - to C 22 -alkyl radical or a C 7 - to C 10 -aralkyl radical and
R 3 and R 4 together form a —(CH 2 ) 4 —, —(CH 2 ) 5 — or —(CH 2 ) 2 —O—(CH 2 ) 2 — bridge or
R 1 is an optionally branched C 14 - to C 22 -alkyl radical,
R 2 , R 3 and R 4 together with the N + form an imidazole or pyridine ring substituted at least by one radical selected from C 1 - to C 8 -alkyl, C 1 - to C 8 -alkoxy, C 5 - to C 7 -cycloalkyl, benzyl or phenyl
and in which
R 21 is an optionally substituted C 1 - to C 22 -alkyl, C 3 - to C 22 -alkenyl, C 5 - to C 7 -cycloalkyl or C 7 - to C 13 -aralkyl radical, and
R 22 to R 24 are each independently a C 6 - to C 10 -aryl radical optionally substituted by at least one radical selected from halogen, C 1 - to C 4 -alkyl, trifluoromethyl, C 1 - to C 4 -alkoxy, trifluoromethoxy, phenyl and phenoxy.

2. The photopolymer formulation according to claim 1 , wherein the coinitiator has a glass transition temperature T g of ≤0° C.

3. The photopolymer formulation according to claim 1 , wherein the coinitiator additionally contains at least one substance of the formula (Ib)

in which R 1 to R 4 are each as defined in claim 1 and
R 22 to R 25 are each independently a C 6 - to C 10 -aryl radical optionally substituted by at least one radical selected from halogen, C 1 - to C 4 -alkyl, trifluoromethyl, C 1 - to C 4 -alkoxy, trifluoromethoxy, phenyl and phenoxy.

4. The photopolymer formulation according to claim 3 , wherein the coinitiator contains the substances of the formulae (Ia) and (Ib) in a molar ratio of 80:20 to 99.99:0.01.

5. The photopolymer formulation according to claim 3 , wherein the coinitiator contains the substances (IIIa) and (IIIb) in the same ratio relative to one another as the substances (Ia) and (Ib).

6. The photopolymer formulation according to claim 1 , wherein the coinitiator additionally contains substances of the formulae (IIIa) and optionally (IIIb)

in which
R 11 to R 14 are each independently C 1 - to C 4 -alkyl and
R 21 to R 24 are each as defined in claim 1 and
R 25 is a C 6 - to C 10 -aryl radical optionally substituted by at least one radical selected from halogen, C 1 - to C 4 -alkyl, trifluoromethyl, C 1 - to C 4 -alkoxy, trifluoromethoxy, phenyl and phenoxy.

7. The photopolymer formulation according to claim 5 , wherein the coinitiator contains the substances of the formulae (Ia) and (Ib) in a molar ratio of 80:20 to 99.99:0.01, wherein the coinitiator contains 1 to 5% by weight, based on the total amount of coinitiator, of salts of the formula (II).

8. The photopolymer formulation according to claim 1 , wherein the coinitiator additionally contains at least one salt of the formula (II)

in which
An − is an anion having an AC log P in the range of 3-6 and
R 1 to R 4 are each as defined in claim 1 .

9. The photopolymer formulation according to claim 8 , wherein the coinitiator contains 0.01 to 10% by weight, based on the total amount of coinitiator, of salts of the formula (II).

10. The photopolymer formulation according to claim 6 , wherein the molar ratio of the substances (IIIa) and optionally (IIIb) to the sum total of the substances (Ia) and optionally (Ib) is ≤15:85.

11. A holographic medium comprising the photopolymer formulation according to claim 1 provided on a substrate.

12. A laminate structure comprising a carrier substrate, a holographic medium according to claim 11 applied thereto, and optionally a covering layer applied to the opposite side of the holographic medium from the carrier substrate.

13. A process for producing a holographic medium, comprising
(I) preparing the photopolymer formulation according to claim 1 by mixing all the constituents,
(II) converting the photopolymer formulation to a form desired for the holographic medium at a processing temperature in the range of from 20 to 40° C. and
(III) curing in the desired form with urethane formation at a crosslinking temperature above the processing temperature.

14. A photopolymer formulation comprising a component reactive toward isocyanates, a polyisocyanate component, a writing monomer and a photoinitiator consisting essentially of at least one dye and a coinitiator, wherein the coinitiator consists essentially of at least one substance of the formula (Ia)

in which
R 1 is an optionally branched C 14 - to C 22 -alkyl radical,
R 2 is an optionally branched and/or optionally substituted C 8 - to C 22 -alkyl radical, a cyclohexyl or cycloheptyl radical, a C 7 - to C 10 -aralkyl radical, or a phenyl radical substituted by nonionic radicals, and
R 3 and R 4 are each independently an optionally branched and/or optionally substituted C 1 - to C 5 -alkyl radical or
R 1 is an optionally branched C 14 - to C 22 -alkyl radical,
R 2 is an optionally branched and/or optionally substituted C 8 - to C 22 -alkyl radical or a C 7 - to C 10 -aralkyl radical and
R 3 and R 4 together form a —(CH 2 ) 4 —, —(CH 2 ) 5 — or —(CH 2 ) 2 —O—(CH 2 ) 2 — bridge or
R 1 is an optionally branched C 14 - to C 22 -alkyl radical,
R 2 , R 3 and R 4 together with the N + form an imidazole or pyridine ring substituted at least by one radical selected from C 1 - to C 8 -alkyl, C 1 - to C 8 -alkoxy, C 5 - to C 7 -cycloalkyl, benzyl or phenyl
and in which
R 21 is an optionally substituted C 1 - to C 22 -alkyl, C 3 - to C 22 -alkenyl, C 5 - to C 7 -cycloalkyl or C 7 - to C 13 -aralkyl radical, and
R 22 to R 24 are each independently a C 6 - to C 10 -aryl radical optionally substituted by at least one radical selected from halogen, C 1 - to C 4 -alkyl, trifluoromethyl, C 1 - to C 4 -alkoxy, trifluoromethoxy, phenyl and phenoxy,
wherein the coinitiator additionally contains at least one salt of the formula (II)

in which
An − is an anion having an AC log P in the range of 3-6 and
R 1 to R 4 are each as above,
and wherein the coiniti

Assignees

• Covestro Deutschland Ag

Inventors

• Berneth Horst
• Rölle Thomas
• Bruder Friedrich-Karl
• Hönel Dennis
• Weiser Marc-Stephan
• Fäcke Thomas
• Hagen Rainer
• Walze Günther

Classifications

• C07F5/027

  Organoboranes and organoborohydrides · CPC title

• G03F7/001 Primary

  Phase modulating patterns, e.g. refractive index patterns · CPC title

• C07D295/037

  with quaternary ring nitrogen atoms · CPC title

• G03F7/029

  Inorganic compounds; Onium compounds; Organic compounds having hetero atoms other than oxygen, nitrogen or sulfur · CPC title

• C07D233/58

  with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring nitrogen atoms · CPC title