Dye compound and photopolymer composition

Abstract

The present invention relates to a compound having a novel structure, a photopolymer composition including the compound as a dye, a hologram recording medium produced from the photopolymer composition, an optical element including the hologram recording medium, and a holographic recording method using the hologram recording medium.

Claims

1. A compound selected from the group consisting of Chemical Formulae 3 to 5: ##STR00012## wherein, in the Chemical Formulae 3 to 5, R.sub.11 and R.sub.12 are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, or a linear or branched alkenyl group having 2 to 20 carbon atoms, X.sub.1 and X.sub.2 are each independently a halogen group; or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, R.sub.30 and R.sub.60 are each independently a halogen group; or a linear or branched alkyl group having 1 to 10 carbon atoms, m and n are each independently 1 to 4 in the Chemical Formulae 3 and 5, and 1 to 3 in the Chemical Formula 4, and Ar.sub.3 is an aromatic ring having 6 to 20 carbon atoms substituted with one or more halogen groups.

2. A photopolymer composition comprising: a polymer matrix or a precursor thereof; a dye containing the compound of claim 1; a photoreactive monomer; and a photoinitiator.

3. The photopolymer composition according to claim 2, wherein the polymer matrix or a precursor thereof includes 1) a reaction product between a compound containing one or more isocyanate groups and a polyol; or 2) a polymer matrix including a (meth)acrylate-based (co)polymer having a silane-based functional group in a branched chain thereof, and a silane crosslinking agent.

4. The photopolymer composition according to claim 3, wherein the silane crosslinking agent includes a linear polyether main chain having a weight average molecular weight of 100 to 2000, and a silane-based functional group bonded at a terminal end or a branched chain of the main chain.

5. The photopolymer composition according to claim 3, wherein the (meth)acrylate-based (co)polymer having a silane-based functional group in a branched chain, includes a (meth)acrylate repeating unit and a (meth)acrylate repeating unit having the silane-based functional group in the branched chain, and has a weight average molecular weight of 100,000 to 1,000,000.

6. The photopolymer composition according to claim 2, wherein the photoreactive monomer includes a polyfunctional (meth)acrylate monomer, or a monofunctional (meth)acrylate monomer.

7. The photopolymer composition according to claim 2, comprising 1% to 80% by weight of the polymer matrix or a precursor thereof; 1% to 80% by weight of the photoreactive monomer; 0.0001% to 10% by weight of the dye; and 0.1% to 20% by weight of the photoinitiator based on the total weight of the photopolymer composition.

8. The photopolymer composition according to claim 2, wherein the photopolymer composition further comprises at least one selected from the group consisting of a catalyst, a phosphate-based compound, and a low refractive index fluorine-based compound.

9. The photopolymer composition according to claim 8, wherein the low refractive index fluorine-based compound includes at least one functional group selected from the group consisting of an ether group, an ester group and an amide group, and at least two difluoromethylene groups.

10. A hologram recording medium produced from the photopolymer composition of claim 2.

11. An optical element comprising the hologram recording medium of claim 10.

12. A holographic recording method comprising selectively polymerizing photoreactive monomers contained in the photopolymer composition of claim 2 by a coherent laser.

13. The optical element of claim 11, wherein the optical element includes a hologram display device.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Hereinafter, the present invention will be described in more detail by way of the following examples. However, these examples are given for illustrative purposes only and are not intended to limit the scope of the present invention thereto.

Preparation Example

Preparation Example 1: Synthesis of Dye Compound

(2) (1) Preparation of methyl 4,5,6,7-tetrahydro-2H-isoindole-1-carboxylate (Product 4)

(3) ##STR00006##

(4) A mixture of sodium hydride (NaH; 60% w/v oil, 4 g, 0.1018 mol), tetrahydrofuran (THF; 500 ml), and ethanol (EtOH, 1 ml) was cooled to 0° C. Ethyl formate (11.3 g, 0.1528 mol) and cyclohexanone (10 g, 0.1018 mol) were added dropwise to the solution, and the reaction mixture was stirred for 6 hours and then kept at room temperature overnight.

(5) Then, 500 ml of water was added and the obtained clear solution was extracted three times with 100 ml of ethyl acetate. The aqueous layer was separated and acidified with concentrated hydrochloric acid (HCl) (pH˜1). The product 2 was extracted with ethyl acetate (100 ml×2), and the organic layer was separated, dried over magnesium sulfate (MgSO.sub.4) and concentrated in vacuo to give 11.6 g of the product 2 in a yield of 90%.

(6) The product 2 (11.6 g, 0.0920 mol) was dissolved in 150 ml of methanol, and then glycine methyl ester hydrochloride (11.5 g, 0.0920 mol) and triethylamine (12.8 g, 0.0920 mol) were added thereto. The reaction mixture was stirred at room temperature overnight and then concentrated in vacuo.

(7) To the concentrated reaction product was added 300 ml of water and the aqueous solution was extracted with chloroform (200 ml×2). The organic layer was separated, washed with 100 ml of brine, then dried over magnesium sulfate and concentrated to give 15.1 g of the product 3 in a yield of 83%.

(8) After the product 3 (15.1 g, 0.0765 mol) was dissolved in 50 ml of methanol, 30% sodium methylate (NaOMe; 14.2 ml, 0.0765 mol) and 50 ml of methanol were added thereto, and the mixture was allowed to react at 90° C. for 3 hours. After cooling the reaction product to room temperature, the solution was diluted with 300 ml of water and extracted with ethyl acetate (100 ml×3). The organic layer was dried over magnesium sulfate and concentrated in vacuo. The residue was purified by column chromatography (hexane/ethyl acetate=9/1) to give 4.5 g of the product 4 in a yield of 33%.

(9) 1H NMR (CDCl.sub.3): 8.8 (1l H, s, NH), 6.65 (1H, s, Ar), 3.83 (3H, s, CH.sub.3), 2.82-2.79 (2H, t, CH.sub.2), 2.56-2.53 (2H, t, CH.sub.2), 1.79-1.70 (4H, m, 2CH.sub.2).

(10) (2) Preparation of 2,4-dibromophenyl 4-formylbenzoate (Produce 6)

(11) ##STR00007##

(12) To terephthalaldehydic acid (5) (1 g, 0.0066 mol) dissolved in 20 ml of dichloromethane, DCC (N,N′-dicyclohexylcarbodiimide (1.9 g, 0.0093 mol) and DMAP (4-dimethylaminopyridine (0.08 g, 0.0006 mol) were added at room temperature, and 2,4-dibromophenol (1.6 g, 0.0066 mol) was additionally added and the mixture was allowed to react with stirring overnight at room temperature.

(13) The precipitate was filtered and the filtrate was concentrated in vacuo, then the residue was stirred with 20 ml of ethanol for 30 minutes, then filtered and dried to give 2.2 g of the product 6 in a yield of 88%.

(14) 1H NMR (CDCl.sub.3): 10.16 (1H, s, CHO), 8.41-8.38 (2H, d, Ar), 8.06-8.03 (2H, d, Ar), 7.83 (1H, s, Ar), 7.55-7.51 (1H, d, Ar), 7.21-7.18 (1H, d, Ar).

(15) (3) Preparation of dimethyl 3,3′-((4-((2,4-dibromophenoxy) carbonyl)phenyl)methylene) bis(4,5,6,7-tetrahydro-2H-isoindole-1-carboxylate) (Produce 7)

(16) ##STR00008##

(17) To the synthesized product 4 (1.7 g, 0.0095 mol) dissolved in 30 ml dichloromethane, toluene sulfonic acid monohydride (0.09 g, 0.00047 mol), tetrabutylammonium iodide (0.03 g, 0.00009 mol) and the synthesized product 6 (2.2 g, 0.0057 mol) were added and the mixture was stirred at room temperature under a nitrogen atmosphere overnight.

(18) The mixture was then washed with saturated sodium hydrogen carbonate (50 ml) and brine (50 ml), and then dried over magnesium sulfate. The solvent was removed in vacuo and the residue was recrystallized from ethanol to give product 7 (yield of about 88%/3 g).

(19) (4) Preparation of dimethyl 14-(4-((2,4-dibromophenoxy)carbonyl)phenyl)-7,7-difluoro -1,3,4,7,10,11,12,13-octahydro-2H-614,714-[1,3,2] diazaborinino[4,3-a:6,1-a′]diisoindole-5,9-dicarboxylate (Dye of Compound 8)

(20) ##STR00009##

(21) DDQ (2,3-dichloro-5,6-dicyano-p-benzoquinone, 1.1 g, 0.0049 mol) was added to a solution of the synthesized product 7 (3 g, 0.0041 mol) dissolved in dichloromethane at 0° C., and the mixture was stirred for 20 minutes under a nitrogen atmosphere.

(22) To this mixture was added dropwise trimethylamine (3.4 ml, 0.0246 mol) and BF.sub.3OEt.sub.2 (5 ml, 0.041 mol) at 0° C., and the reaction mixture was stirred at 0° C. for 20 minutes and then at room temperature overnight. The mixture was then washed with 50 ml saturated sodium bicarbonate and 50 ml of brine and dried over magnesium sulfate. The solvent was removed in vacuo and the residue was purified by column chromatography (hexane/ethyl acetate=2/1) to give the dye of compound 8 (yield of about 70.9%, 2.2 g).

(23) 1) 1H NMR (CDCl.sub.3): 8.41-8.39 (2H, d, Ar), 7.85 (1H, s, Ar), 7.57-7.53 (1H, d, Ar), 7.49-7.47 (2H, d, Ar), 7.28-7.25 (1H, d, Ar), 3.99 (6H, s, 2CH3), 2.61-2.56 (4H, t, 2CH.sub.2), 1.63-1.56 (8H, m, 4CH.sub.2), 1.47-1.41 (4H, m, 2CH.sub.2).

(24) 2) UV-VIS spectrum: λmax=530 nm

(25) The synthesized dye synthesized was diluted to 0.001 wt % in a methyl ethyl ketone (MEK) solvent, and absorbance (%) in a wavelength range from 380 nm to 780 nm was measured by using a UV-Vis spectrophotometer to determine the maximum absorption wavelength.

(26) (5) Preparation of dimethyl 14-(4-((2,4-dibromophenoxy)carbonyl)phenyl)-7,7-difluoro -7H-6λ4,7λ4-[1,3,2]diazaborinino[4,3-a:6,1-a′]diisoindole-5,9-dicarboxylate (Dye of Compound 9)

(27) ##STR00010##

(28) The synthesized product 8 (1.5 g, 0.0019 mol) was dissolved in 100 ml of toluene and the solution was heated to reflux. 100 ml of toluene in which DDQ (2,3-dichloro-5,6-dicyano-p-benzoquinone (3.9 g, 0.0175 mol) was dissolved was added and reflux was continued for 4 hours. The reaction mixture was cooled and the solvent was removed in vacuo. The residue was dissolved in ethyl acetate, and the solution was washed with saturated sodium hydrogencarbonate (100 ml×3) and brine (100 ml) and dried over magnesium sulfate. The solvent was removed in vacuo and the residue was purified by column chromatography (hexane/ethyl acetate=2/1). The product was stirred in 20 ml of methanol for 30 minutes and filtered to give a dye of compound 9 (yield of 65%, 2.1 g).
UV-VIS spectrum: λmax=633 nm

Preparation Example 2: Preparation of Non-Reactive Low Refractive Index Material

(29) 20.51 g of 2,2′-((oxybis(1,1,2,2-tetrafluoroethane-2,1-diyl))bis(oxy))bis(2,2-difluoroethan -1-ol) was placed in a 1000 ml flask, and then dissolved in 500 g of tetrahydrofuran and 4.40 g of sodium hydride (60% dispersion in mineral oil) was carefully added several times while stirring at 0° C. for 20 minutes, 12.50 ml of 2-methoxyethoxymethyl chloride was slowly dropped. When it was confirmed that all of the reactants have been consumed by .sup.1H NMR, the reaction solvent was removed under reduced pressure. After extraction was performed three times with 300 g of dichloromethane, the organic layer was collected, and filtered with magnesium sulfate, applied to reduced pressure to remove all dichloromethane. Thereby, 29 g of a liquid product having a purity of 95% or more was obtained at a yield of 98%.

Preparation Example 3: Preparation of (meth)Acrylate-Based (Co)Polymer in which Silane Functional-Based Group is Located in a Branched Chain

(30) 69.3 g of butyl acrylate and 20.7 g of KBM-503 (3-methacryloxypropyltrimethoxysilane) were placed in a 2 L jacket reactor, and diluted with 700 g of ethyl acetate. The reaction temperature was set at about 70° C. and stirring was performed for about one hour. 0.02 g of n-dodecyl mercaptan was further added and stirring was performed for about 30 minutes. Then, 0.06 g of AIBN, which is a polymerization initiator, was added and polymerization was allowed to proceed for 4 hours or more at the reaction temperature and maintained until the content of the residual acrylate became less than 1%, thereby preparing (meth)acrylate-based (co)polymer (weight average molecular weight: about 900,000, Si—(OR).sub.3 equivalent: 1019 g/piece) in which a silane-based functional group is located on a branched chain.

Preparation Example 4: Preparation of Silane Crosslinking Agent

(31) 19.79 g of KBE-9007 (3-isocyanatopropyltriethoxysilane), 12.80 g of PEG-400 and 0.57 g of DBTDL were placed in a 1000 ml flask, and diluted with 300 g of tetrahydrofuran. Stirring was performed at room temperature until being confirmed by TLC that all the reaction material had been consumed, the reaction solvent was all removed under reduced pressure.

(32) 28 g of a liquid product having a purity of 95% or more was separated at a yield of 91% through column chromatography under a developing solution of dichloromethane: methyl alcohol=methyl alcohol=30:1 to obtain a silane crosslinking agent.

Examples and Comparative Examples: Preparation of Photopolymer Composition

(33) As shown in Table 1 below, the (meth)acrylate-based (co)polymer of Preparation Example 3 in which the silane-based functional group is located in a branched chain, a photoreactive monomer (high refractive index acrylate, refractive index of 1.600, HR6022 [Niwon Specialty Chemical]), the non-reactive low refractive index material of Preparation Example 2, the dipyrromethene boron complex of Chemical Formula 10, tributyl phosphate [TBP], molecular weight 266.31, refractive index 1.424, manufactured by Sigma-Aldrich), Ethyl Violet and Eosin (dyes, products at Sigma-Aldrich), Ebecryl P-115 (SK entis), Borate V (Spectra Group), Irgacure 250 (Onium salt, BASF) and methyl isobutyl ketone (MIBK) were mixed in a state where light was blocked, and stirred for about 10 minutes with a Paste mixer to obtain a clear coating solution.

(34) The silane crosslinking agent of Preparation Example 4 was added to the coating solution and further stirred for 5 to 10 minutes. Then, DBTDL as a catalyst was added to the coating solution, stirred for about 1 minute, then coated to a thickness of 7 μm on a TAC substrate having a thickness of 80 μm using a Meyer bar and dried at 40° C. for 1 hour.

Experimental Example: Holographic Recording

(35) (1) The photopolymer-coated (hologram recoding medium) surfaces prepared in each of Examples and Comparative Examples were laminated on a slide glass, and fixed so that a laser first passed through the glass surface at the time of recording.

(36) (2) Measurement of Diffraction Efficiency (η)

(37) A holographic recording was done via interference of two interference lights (reference light and object light), and the transmission-type recording was done so that the two beams were incident on the same side of the sample. The diffraction efficiencies are changed according to the incident angle of the two beams, and become non-slanted when the incident angles of the two beams are the same. In the non-slanted recording, the diffraction grating is generated vertically to the film because the incident angles of the two beams are the same on the normal basis.

(38) The recording (2θ=45°) was done in a transmission-type non-slanted manner using a laser with a wavelength of 532 nm or a laser with a wavelength of 633 nm, and the diffraction efficiency (η) was calculated according to the following Equation 1.

(39) $\begin{array}{cc}\eta =\frac{P_D}{P_D+P_T}& \left[\mathrm{Equation}1\right]\end{array}$

(40) wherein, in Equation 1, η is a diffraction efficiency, P.sub.D is an output amount (mW/cm.sup.2) of the diffracted beam of a sample after recording, and P.sub.T is an output amount (mW/cm.sup.2) of the transmitted beam of the recorded sample.

(41) (3) Measurement of the refractive index modulation value(n)

(42) The lossless dielectric grating of the transmission-type hologram can calculate the refractive index modulation value (Δn) from the following Equation 2.

(43) $\begin{array}{cc}\eta \left(\mathrm{DE}\right)={\sin }^2\left(\sqrt{v^2}\right)={\sin }^2\left(\frac{\pi \Delta \mathrm{nd}}{\lambda \cos \theta }\right)& \left[\mathrm{Equation}2\right]\end{array}$

(44) wherein, in Equation 2, d is a thickness of the photopolymer layer, (Δn) is a refractive index modulation value, (η)DE) is a diffraction efficiency, and λ is a recording wavelength.

(45) TABLE-US-00001 TABLE 1 Measurement Results of Experimental Examples of Photopolymer Compositions of Examples (unit: g) and Holographic Recording Medium Prepared Therefrom Comparative Comparative Comparative Category Example 1 Example 2 Example 3 Example 4 Example 1 Example 2 Example 3 (Meth)acrylate- Preparation 21.5 21.5 21.5 21.5 21.5 21.5 21.5 based Example 3 copolymer Linear Preparation 6.1 6.1 6.1 6.1 6.1 6.1 6.1 silane Example 4 crosslinking agent Photoreactive HR6022 40.2 40.2 40.2 40.2 40.2 40.2 40.2 monomer Dye Compound 8 0.1 0.1 Compound 9 0.1 0.15 Ethyl Violet 0.1 (Aldrich) Eosin 0.1 (Aldrich) Compound 10 0.1 (Carboxyl group- unintroduced dye) Initiator Amine 1.5 1.5 1.5 (Ebecryl P- 115) Borate salt 0.12 0.15 0.26 0.26 0.26 0.26 0.26 (Borate V) Onium salt 0.1 0.1 0.1 0.1 0.1 0.1 0.1 (Irgacure 250) Non- Preparation 30 30 30 30 30 30 30 reactive low Example2 refractive index material Catalyst DBTDL(dibutyltin 0.02 0.02 0.02 0.02 0.02 0.02 0.02 dilaurate) Additive Tego Rad 0.22 0.22 0.22 0.22 0.22 0.22 0.22 2500 Solvent MIBK 295 295 295 296 300 300 300 Coating thickness (unit: μm) 6.5 6.5 6.5 6.5 6.5 6.5 6.5 Δn 0.023 0.030 0.023 0.027 0.018 0.014 0.010 *[Chemical Formula 10: dipyromethane boron complex compound]

(46) As shown in Table 1 above, it was confirmed that the hologram recording medium of Examples 1 to 4 can realize a refractive index modulation value (Δn) of 0.022 or more at a thickness of 6.5 μm. In contrast, it was confirmed that the hologram recording medium of Comparative Examples 1 and 2 has a relatively low diffraction efficiency as compared with Examples. The diffraction efficiency of the hologram recording medium of Comparative Example 3 using the dipyrromethene boron complex of Chemical Formula 10 in which the carboxyl group was not introduced was found to be extremely low.