FLUORINATED COMPOUND, PHOTOPOLYMERIZABLE COMPOSITION, HOLOGRAM RECORDING MEDIUM, PREPARATION METHOD THEREOF AND OPTICAL ELEMENT COMPRISING THE SAME

Abstract

The present invention relates to a fluorinated compound, a photopolymerizable composition, a hologram recording medium, a preparation method thereof, and an optical element comprising the same. The fluorinated compound is included in a photopolymerizable composition, thereby being able to provide a hologram recording medium that not only has excellent optical recording properties but also exhibits transparent optical properties and excellent reliability even in high temperature and high humidity environments, and an optical element including the same.

Claims

1. A fluorinated compound represented by the following Chemical Formula 1: ##STR00028## wherein, in the Chemical Formula 1, Z.sup.1 is O or NH, Z.sup.2 is a single bond, O or NH, L.sup.1 is a single bond or a divalent to hexavalent organic group in which hydroxy groups have been removed from a polyol having 2 to 6 hydroxy groups, n and m are each independently an integer of 1 to 5, wherein the sum of n and m is 2 to 6, R.sup.1 is a methyl group or an ethyl group, and at least one of R.sup.2 to R.sup.4 is a fluorine-containing substituent, which is an alkyl group having 1 to 20 carbon atoms substituted with 2 or more fluorines, a cycloalkyl group having 3 to 30 carbon atoms substituted with 2 or more fluorines, or an aryl group having 6 to 30 carbon atoms substituted with 2 or more fluorines, when R.sup.2 and R.sup.3 are not fluorine-containing substituents, R.sup.2 and R.sup.3 are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heterocycloalkyl group having 4 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms or an arylalkyl group having 7 to 40 carbon atoms, or a substituent in which at least one CH.sub.2 of the above substituents is substituted with O, S or NH, and when R.sup.4 is not a fluorine-containing substituent, R.sup.4 is an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a cycloalkylalkyl group having 7 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms or an arylalkyl group having 7 to 40 carbon atoms, or is a substituent in which at least one CH.sub.2 of the above substituents is substituted with O, S, or NH.

2. The fluorinated compound according to claim 1, wherein L.sup.1 in the Chemical Formula 1 is a single bond; or a trivalent organic group in which hydroxy groups have been removed from glycerol which is a triol.

3. The fluorinated compound according to claim 1, wherein the fluorine-containing substituent is a straight chain alkyl group having 1 to 20 carbon atoms substituted with 2 or more fluorines.

4. The fluorinated compound according to claim 1, wherein the fluorine-containing substituent is (CH.sub.2).sub.a(CF.sub.2).sub.bCHF.sub.2 or (CH.sub.2).sub.a(CF.sub.2).sub.bCF.sub.3, where a is an integer of 0 to 3, and b is an integer of 0 to 19.

5. The fluorinated compound according to claim 1, wherein when R.sup.2 and R.sup.3 in the Chemical Formula 1 are not fluorine-containing substituents, R.sup.2 and R.sup.3 are each independently hydrogen, a straight chain alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a heterocycloalkyl group having 4 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms or (R.sup.5O).sub.pR.sup.6, where R.sup.5 is an alkylene group having 1 to 6 carbon atoms, R.sup.6 is an alkyl group having 1 to 6 carbon atoms, and p is an integer of 1 to 12.

6. The fluorinated compound according to claim 1, wherein when R.sup.4 in the Chemical Formula 1 is not a fluorine-containing substituent, R.sup.4 is a straight chain alkyl group having 2 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms or (R.sup.5O).sub.pR.sup.6, where R.sup.5 is an alkylene group having 1 to 6 carbon atoms, R.sup.6 is an alkyl group having 1 to 6 carbon atoms, and p is an integer of 1 to 12.

7. The fluorinated compound according to claim 1, wherein the fluorinated compound represented by the Chemical Formula 1 comprises at least one fluorinated compound selected from the group consisting of fluorinated compounds represented by the following Chemical Formulas 1-1-1 to 1-1-5 and the following Chemical Formulas 1-2-1 to 1-2-5: ##STR00029## wherein, in the Chemical Formula 1-1-1, R.sup.a1 is a methyl group or an ethyl group, R.sup.b1 and R.sup.b2 are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms, R.sup.c1 is CF.sub.3 or CHF.sub.2, Z.sup.a1 is O or NH, p1 and p2 are each independently an integer of 0 to 3, and q1 is an integer of 0 to 9, ##STR00030## wherein, in the Chemical Formula 1-1-2, R.sup.a2 is a methyl group or an ethyl group, R.sup.b3 and R.sup.b4 are each independently a cyclohexyl group, a tetrahydropyranyl group, or a phenyl group, R.sup.c2 is CF.sub.3 or CHF.sub.2, Z.sup.a2 is O or NH, and q2 is an integer of 0 to 9, ##STR00031## wherein, in the Chemical Formula 1-1-3, R.sup.a3 is a methyl group or an ethyl group, R.sup.b5 and R.sup.b6 are each independently CF.sub.3 or CHF.sub.2, R.sup.c3 is an alkyl group having 1 to 4 carbon atoms, Z.sup.a3 is O or NH, p3 and p4 are each independently an integer of 0 to 9, and q3 is an integer of 0 to 3, ##STR00032## wherein, in the Chemical Formula 1-1-4, R.sup.a4 is a methyl group or an ethyl group, R.sup.b7 is CF.sub.3 or CHF.sub.2, R.sup.c4 and R.sup.c5 are each independently an alkyl group having 1 to 4 carbon atoms, Z.sup.a4 is O or NH, p5 is an integer of 0 to 9, and q4 and q5 are each independently an integer of 0 to 3, ##STR00033## wherein, in the Chemical Formula 1-1-5, R.sup.a5 is a methyl group or an ethyl group, R.sup.b8 is CF.sub.3 or CHF.sub.2, R.sup.b9 is a cyclohexyl group, a tetrahydropyranyl group, or a phenyl group, R.sup.c6 is an alkyl group having 1 to 4 carbon atoms, Z.sup.a5 is O or NH, p6 is an integer of 0 to 9, and q6 is an integer of 0 to 3, ##STR00034## wherein, in the Chemical Formula 1-2-1, R.sup.a6 is a methyl group or an ethyl group, R.sup.b10 and R.sup.b11 are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms, R.sup.c7 and R.sup.c8 are each independently CF.sub.3 or CHF.sub.2, Z.sup.a6 is O or NH, p7 and p8 are each independently an integer of 0 to 3, and q7 and q8 are each independently an integer of 0 to 9, ##STR00035## wherein, in the Chemical Formula 1-2-2, R.sup.a7 is a methyl group or an ethyl group, R.sup.b12 and R.sup.b13 are each independently CF.sub.3 or CHF.sub.2, R.sup.c9 and R.sup.c10 are each independently an alkyl group having 1 to 4 carbon atoms, Z.sup.a7 is O or NH, p9 and p10 are each independently an integer of 0 to 9, and q9 and q10 are each independently an integer of 0 to 3, ##STR00036## wherein, in the Chemical Formula 1-2-3, R.sup.a8 is a methyl group or an ethyl group, R.sup.b14 and R.sup.b15 are each independently a cyclohexyl group, a tetrahydropyranyl group, or a phenyl group, R.sup.c11 and R.sup.c12 are each independently CF.sub.3 or CHF.sub.2, Z.sup.a8 is O or NH, and q11 and q12 are each independently an integer of 0 to 9, ##STR00037## wherein, in the Chemical Formula 1-2-4, R.sup.a9 is a methyl group or an ethyl group, R.sup.b16 is CF.sub.3 or CHF.sub.2, R.sup.b17 is a cyclohexyl group, a tetrahydropyranyl group, or a phenyl group, R.sup.c13 and R.sup.c14 are each independently an alkyl group having 1 to 4 carbon atoms, Z.sup.a9 is O or NH, p11 is an integer of 0 to 9, and q13 and q14 are each independently an integer of 0 to 3, ##STR00038## wherein, in the Chemical Formula 1-2-5, R.sup.a10 is a methyl group or an ethyl group, R.sup.b18 is CF.sub.3 or CHF.sub.2, R.sup.c15 to R.sup.c17 are each independently an alkyl group having 1 to 4 carbon atoms, Z.sup.a10 is O or NH, p12 is an integer of 0 to 9, and q15 to q17 are each independently an integer of 0 to 3.

8. A photopolymerizable composition comprising: the fluorinated compound according to claim 1; a polymer matrix or a precursor thereof; a photoreactive monomer; and a photoinitiator system.

9. A hologram recording medium comprising a photopolymer layer formed from the photopolymerizable composition according to claim 8.

10. A method for preparing a hologram recording medium, comprising the steps of: applying the photopolymerizable composition according to claim 8 to form a photopolymer layer; and irradiating a coherent laser onto a predetermined region of the photopolymer layer and selectively polymerizing a photoreactive monomer contained in the photopolymer layer to record optical information.

11. An optical element comprising the hologram recording medium according to claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0224] FIG. 1 schematically shows the recording equipment setup for hologram recording. Specifically, FIG. 1 schematically shows the process in which a laser of a predetermined wavelength is radiated from the light source 10, and irradiated onto the PP (hologram recording medium) 80 located on one surface of a mirror 70 via mirrors 20 and 20, an iris 30, a spatial filter 40, an iris 30, a collimation lens 50, and PBS (Polarized Beam Splitter) 60.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0225] Hereinafter, the action and effect of the invention will be described in more detail with reference to specific examples of the invention. However, these examples are presented for illustrative purposes only, and the scope of the invention is not limited thereby in any way.

[0226] In the following Preparation Examples, Examples, and Comparative Examples, the content of raw materials, and the like means the content based on solid content, unless otherwise specified.

Preparation Example 1: Preparation of Fluorinated Compound

[0227] 100 g of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 42 g of potassium carbonate, and 14 g of epichlorohydrin were added to a 2L jacketed reactor and allowed to react at 70 C. for 24 hours. After cooling to room temperature, the reaction product was filtered, the resulting filtrate was washed with 700 mL of chloroform and 500 mL of water, and the organic layer was concentrated. 63 g of a first intermediate product was obtained through high vacuum distillation.

[0228] 100 g of 2,2-bis(hydroxymethyl) propionic acid, 520 g of 2-(2-methoxyethoxy)ethyl chloride, 340 g of potassium hydroxide, 1 g of DABCO, and 500 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 200 g of a second intermediate compound was obtained through high vacuum distillation.

[0229] 100 g of the previously obtained first intermediate product, 62 g of the previously obtained second intermediate product, 2 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 100 g of a fluorinated compound represented by the following Chemical Formula a was obtained through high vacuum distillation.

##STR00018##

Preparation Example 2: Preparation of Fluorinated Compound

[0230] 100 g of 2,2,3,3,4,4,5,5,6,6-decafluoro-1-hexanol, 49 g of potassium carbonate and 17 g of epichlorohydrin were added to a 2 L jacketed reactor, and allowed to react at 70 C. for 24 hours. After cooling to room temperature, the reaction product was filtered, the resulting filtrate was washed with 700 mL of chloroform and 500 mL of water, and the organic layer was concentrated. 90 g of a first intermediate product was obtained through high vacuum distillation.

[0231] 100 g of 2,2-bis(hydroxymethyl) propionic acid, 352 g of 2-methoxyethyl chloride, 340 g of potassium hydroxide, 1 g of DABCO, and 500 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 150 g of a second intermediate compound was obtained through high vacuum distillation.

[0232] 100 g of the previously obtained first intermediate product, 40 g of the previously obtained second intermediate product, 2 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, and kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 100 g of a fluorinated compound represented by the following Chemical Formula b was obtained through high vacuum distillation.

##STR00019##

Preparation Example 3: Preparation of Fluorinated Compound

[0233] 100 g of 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1-heptanol, 42 g of potassium carbonate and 14 g of epichlorohydrin were added to a 2 L jacketed reactor, and allowed to react at 70 C. for 24 hours. After cooling to room temperature, the reaction product was filtered, the resulting filtrate was washed with 700 mL of chloroform and 500 mL of water, and the organic layer was concentrated. 80 g of a first intermediate product was obtained through high vacuum distillation.

[0234] 100 g of 2,2-bis(hydroxymethyl) propionic acid, 352 g of 2-methoxyethyl chloride, 340 g of potassium hydroxide, 1 g of DABCO, and 500 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 150 g of a second intermediate compound was obtained through high vacuum distillation.

[0235] 100 g of the previously obtained first intermediate product, 33 g of the previously obtained second intermediate product, 2 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 95 g of a fluorinated compound represented by the following Chemical Formula c was obtained through high vacuum distillation.

##STR00020##

Preparation Example 4: Preparation of Fluorinated Compound

[0236] 100 g of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 42 g of potassium carbonate and 14 g of epichlorohydrin were added to a 2 L jacketed reactor, and allowed to react at 70 C. for 24 hours. After cooling to room temperature, the reaction product was filtered, the resulting filtrate was washed with 700 mL of chloroform and 500 mL of water, and the organic layer was concentrated. 63 g of a first intermediate product was obtained through high vacuum distillation.

[0237] 100 g of the previously obtained first intermediate product, 25 g of 2,2-bis(hydroxymethyl) propionic acid, 2 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 70 g of a fluorinated compound represented by the following Chemical Formula d was obtained through high vacuum distillation.

##STR00021##

Preparation Example 5: Preparation of Fluorinated Compound

[0238] 100 g of 2,2-bis(hydroxymethyl) propionic acid, 352 g of 2-methoxyethyl chloride, 340 g of potassium hydroxide, 1 g of DABCO, and 500 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 150 g of a first intermediate compound was obtained through high vacuum distillation.

[0239] 100 g of 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1-heptanol, 72g of the previously obtained first intermediate product, 2 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 120 g of a fluorinated compound represented by the following Chemical Formula e was obtained through high vacuum distillation.

##STR00022##

Preparation Example 6: Preparation of Fluorinated Compound

[0240] 20 g of 2,2-bis(hydroxymethyl) propionic acid, 295 g of 7-bromo-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoroheptane, 67 g of potassium hydroxide, 1 g of DABCO, and 100 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 90 g of a first intermediate compound was obtained through high vacuum distillation.

[0241] 50 g of 2-(2-methoxyethoxy)-1-ethanol, 302g of the previously obtained first intermediate product, 4 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 120 g of a fluorinated compound represented by the following Chemical Formula f was obtained through high vacuum distillation.

##STR00023##

Preparation Example 7: Preparation of Fluorinated Compound

[0242] 50 g of 2,2-bis(hydroxymethyl) propionic acid, 196 g of 7-bromo-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoroheptane, 84 g of potassium hydroxide, 1 g of DABCO, and 100 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 90 g of a first intermediate compound was obtained through high vacuum distillation.

[0243] 90g of the previously obtained first intermediate product, 42 g of 2-(2-methoxyethoxy)-1-ethanol, 46 g of potassium hydroxide, 1 g of DABCO, and 100 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 90 g of a second intermediate product was obtained through high vacuum distillation.

[0244] 50 g of 2-(2-methoxyethoxy)-1-ethanol, 217 g of the previously obtained second intermediate product, 4 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 200 g of a fluorinated compound represented by the following Chemical Formula g was obtained through high vacuum distillation.

##STR00024##

Preparation Example 8: Preparation of Fluorinated Compound

[0245] 100 g of 2-methoxyethanol, 182 g of potassium carbonate and 61 g of epichlorohydrin were added to a 2 L jacketed reactor, and allowed to react at 70 C. for 24 hours. After cooling to room temperature, the reaction product was filtered, the resulting filtrate was washed with 700 mL of chloroform and 500 mL of water, and the organic layer was concentrated. 65 g of a first intermediate product was obtained through high vacuum distillation.

[0246] 50 g of 2,2-bis(hydroxymethyl) propionic acid, 196 g of 7-bromo-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoroheptane, 84 g of potassium hydroxide, 1 g of DABCO, and 100 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 90 g of a second intermediate product was obtained through high vacuum distillation.

[0247] 90 g of the previously obtained second intermediate product, 42 g of 2-(2-methoxyethoxy)-1-ethanol, 46 g potassium hydroxide, 1 g of DABCO, and 100 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 90 g of a third intermediate product was obtained through high vacuum distillation.

[0248] 50 g of the previously obtained first intermediate product, 126 g of the previously obtained third intermediate product, 4 g of sulfuric acid, and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 120 g of a fluorinated compound represented by the following Chemical Formula h was obtained through high vacuum distillation.

##STR00025##

Preparation Example 9: Preparation of Fluorinated Compound

[0249] 100 g of 2-methoxyethanol, 182 g of potassium carbonate, and 61 g of epichlorohydrin were added to a 2 L jacketed reactor, and allowed to react at 70 C. for 24 hours. After cooling to room temperature, the reaction product was filtered, the resulting filtrate was washed with 700 mL of chloroform and 500 mL of water, and the organic layer was concentrated. 65 g of a first intermediate product was obtained through high vacuum distillation.

[0250] 20 g of 2,2-bis(hydroxymethyl) propionic acid, 295 g of 7-bromo-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluoroheptane, 67 g potassium hydroxide, 1 g of DABCO, and 100 mL of toluene were added to a 2 L jacketed reactor, and allowed to react under reflux for 24 hours. After cooling to room temperature, 500 mL of water was added to separate the aqueous layer, 500 mL of ethyl acetate and 700 mL of hydrochloric acid were added thereto and subjected to neutralization, and the organic layer was concentrated. 90 g of a second intermediate product was obtained through high vacuum distillation.

[0251] 30 g of the previously obtained first intermediate product, 105 g of the previously obtained second intermediate product, 2 g of sulfuric acid and 300 mL of xylene were added to a 2 L jacketed reactor, kept under reflux conditions and the resulting water was removed by use of a Dean-Stark Trap. After cooling to room temperature, it was washed with 300 mL of water, and the organic layer was concentrated. 110 g of a fluorinated compound represented by the following Chemical Formula i was obtained through high vacuum distillation.

##STR00026##

Preparation Example 10: Preparation of (Meth)Acrylic-Based Polyol

[0252] 132 g of butyl acrylate, 420 g of ethyl acrylate, and 48 g of hydroxybutyl acrylate were added to a 2 L jacketed reactor, and diluted with 1200 g of ethyl acetate. The reaction temperature was set to 6070 C., and the mixture was stirred for about 30 minutes to 1 hour. 0.42 g of n-dodecyl mercaptan (n-DDM) was further added, and stirring was further performed for about 30 minutes. Then, 0.24 g of AIBN as a polymerization initiator was added, polymerization was carried out at the reaction temperature for 4 hours or more, and kept until the residual acrylate content became less than 1%. Thereby, a (meth)acrylate-based copolymer (weight average molecular weight of about 300,000, OH equivalent of about 1802 g/equivalent) in which the hydroxy group is located in the branched chain was prepared.

Example 1: Preparation of Photopolymer Composition and Hologram Recording Medium

(1) Preparation of photopolymer composition

[0253] 1.27 g of poly(methylhydrosiloxane) (Sigma-Aldrich, number average molecular weight: about 390, SiH equivalent: about 103 g/equivalent) as a siloxane-based polymer and 11.12 g of (meth)acrylic-based polyol prepared in Preparation Example 10 were first mixed (SiH/OH molar ratio=2.0).

[0254] Then, 20 g of HR6042 (Miwon Specialty Chemical, refractive index of 1.60) as a photoreactive monomer, 0.08 g of photosensitizing dye H-Nu 640 (Spectra Group), 0.3 g of borate V as a coinitiator, 0.05 g of H-Nu 254 (Spectra), 10 g of the fluorinated compound prepared in Preparation Example 1 as a plasticizer and 26 g of methyl isobutyl ketone (MIBK) as a solvent were added, and the mixture was stirred with a paste mixer for about 30 minutes while blocking light. After that, a photopolymer composition was prepared by adding Karstedt (Pt-based) catalyst for matrix crosslinking.

(2) Preparation of Hologram Recording Media

[0255] The photopolymer composition was coated to a predetermined thickness on a 60 m thick TAC substrate using a Mayer bar, and dried at 80 C. for 10 minutes. The thickness of the photopolymer layer after drying was about 15 m.

[0256] The diffraction grating was recorded using the same setup as in FIG. 1. Specifically, when the prepared photopolymer layer was laminated on a mirror and then irradiated with a laser, a notch filter hologram having periodic refractive index modulation in the thickness direction through interference between incident light L and light reflected from a mirror L can be recorded. In this example, a notch filter hologram was recorded with an incident angle of 0 (degree). A notch filter and a Bragg reflector are optical devices that reflect only light of a specific wavelength, and have a structure in which two layers with different refractive indexes are stacked periodically and repeatedly at a certain thickness.

Examples 2 to 11 and Comparative Examples 1 to 4: Preparation of Photopolymer Composition and Hologram Recording Medium

[0257] A photopolymer composition and a hologram recording medium were prepared in the same manner as in Example 1, except that the components and contents of the photopolymer composition were different as shown in Table 1 below.

TABLE-US-00001 TABLE 1 Photosensitizing dye Red Dye Green Dye (H-Nu (Safranin Recording 640) O) Plasticizer wavelength Example 1 0.08 g [Chemical Formula 660 nm a] 10 g Example 2 0.08 g [Chemical Formula 660 nm b] 10 g Example 3 0.05 g [Chemical Formula 532 nm c] 10 g Example 4 0.08 g [Chemical Formula 660 nm c] 10 g Example 5 0.08 g [Chemical Formula 660 nm d] 10 g Example 6 0.05 g [Chemical Formula 532 nm e] 10 g Example 7 0.08 g [Chemical Formula 660 nm e] 10 g Example 8 0.08 g [Chemical Formula 660 nm f] 10 g Example 9 0.08 g [Chemical Formula 660 nm g] 12 g Example 10 0.05 g [Chemical Formula 532 nm h] 12 g Example 11 0.05 g [Chemical Formula 532 nm i] 12 g Comparative 0.08 g [Chemical Formula 660 nm Example 1 j] 10 g Comparative 0.08 g [Chemical Formula 660 nm Example 2 j] 5 g Comparative 0.05 g [Chemical Formula 532 nm Example 3 j] 5 g Comparative 0.05 g [Chemical Formula 532 nm Example 4 k] 10 g

##STR00027##

Test Example: Performance Evaluation of Hologram Recording Media

(1) Diffraction Efficiency

[0258] Diffraction efficiency (n) was determined through the following Equation 1.

[00003]$\begin{array}{cc}\left(\%\right)=\left\{P_D/\left(P_D+P_T\right)\right\}100& \left[\mathrm{Equation}l\right]\end{array}$ [0259] wherein, in Equation 1, n is the diffraction efficiency, PD is the output amount (mW/cm.sup.2) of the diffracted beam of the sample after recording, and PT is the output amount (mW/cm.sup.2) of the transmitted beam of the sample after recording.

(2) Refractive Index Modulation Value (n)

[0260] The refractive index modulation value (n) was determined through the following Equation 2 and Bragg's equation.

[00004]$\begin{array}{cc}={\tanh }^2.Math.\frac{\mathrm{nd}}{{\left({\cos }^2-\frac{}{n}\cos \right)}^{1/2}}.Math.& \left[\mathrm{Equation}2\right]\end{array}$$\begin{array}{cc}\cos \left(0-\right)=-\frac{}{2n}& \left[\mathrm{Bragg}\text{'}s\mathrm{Equation}\right]\end{array}$ [0261] wherein, in Equations, n is the diffraction efficiency (DE), d is the thickness of the photopolymer layer, is the wavelength of incident light for recording (660 nm or 532 nm), is the angle of incidence of the incident light for recording, is the slant angle of the grating, n is the refractive index modulation value, n is the refractive index of the photopolymer, and means the diffraction grating period. In the above Examples and Comparative Examples, since holograms were recorded using the notch filter method, both 0 (incident angle) and (slant angle of the grating) were 0.

(3) Haze

[0262] Haze was measured using a HAZE METER (Murakami Color Research Laboratory, HM-150) in accordance with JIS K 7136. The measurement light was incident on the substrate side surface of the hologram recording medium.

(4) Peak Variation

[0263] In order to evaluate the reliability of a hologram recording medium recorded with a diffraction grating in a high temperature/high humidity environment, the degree of movement of the wavelength that shows the maximum reflectance before and after exposing the sample recorded with the diffraction grating to high temperature/high humidity conditions was confirmed.

[0264] First, the specific wavelength (or wavelength band) (A.sub.0) at which the sample recorded with the diffraction grating had the highest reflectance (i.e., lowest transmittance) was analyzed (analyzed at room temperature and non-high humidity conditions). UV-Vis spectroscopy was used for the analysis, and the analysis wavelength range was 300 to 1,200 nm.

[0265] Subsequently, the same sample was stored at a temperature of 60 C. and a relative humidity of 90% for 72 hours, and the wavelength (or wavelength band) (A.sub.1) with the maximum reflectance (minimum transmittance) was recorded in a similar manner. The peak variation, which is the degree of movement of the wavelength with the lowest transmittance before and after evaluation, was measured according to the following Equation 3. At this time, it was assumed that sample deformation (e.g., shrinkage or expansion) did not affect the surface pitch and occurred only in the direction perpendicular to the sample surface.

[00005]$\begin{array}{cc}\mathrm{Peak}\mathrm{variation}=\left\{.Math.1-A_1/A_0.Math.\right\}100& \left[\mathrm{Equation}3\right]\end{array}$

(5) Refractive Index Variation

[0266] In order to evaluate the stability of the hologram recording medium in a high temperature/high humidity environment before recording the diffraction grating, the degree of refractive index change before and after exposing the sample to high temperature/high humidity conditions before recording the diffraction grating was confirmed.

[0267] Specifically, the hologram recording media before recording prepared as in Examples and Comparative Examples were stored under constant temperature (20 to 25 C.) and constant humidity (relative humidity of 40 to 50%) conditions, and then bleached with white LED before recording. Samples that were not exposed to a high temperature/high humidity environment were prepared. Then, the refractive index no of the sample was measured using a prism coupler (SPA-3DR, SAIRON TECHNOLOGY).

[0268] On the other hand, the hologram recording medium before recording prepared as in Examples and Comparative Examples was stored at a temperature of 60 C. and relative humidity of 90% for 72 hours, bleached with white LED, and samples exposed to a high temperature/high humidity environment before recording were prepared. Then, the refractive index 1 of the sample was measured using a prism coupler.

[0269] The refractive index variation was calculated by substituting no and ni into the following Equation 4.

[00006]$\begin{array}{cc}\mathrm{Refractive}\mathrm{index}\mathrm{variation}\left(\%\right)=\left\{.Math.1-n_1/n_0.Math.\right\}100& \left[\mathrm{Equation}4\right]\end{array}$ [0270] wherein, in Equation 4, no is the refractive index of a sample in which the hologram recording medium before recording is stored at a temperature of 20 to 25 C. and a relative humidity of 40 to 50% and then bleached with a white LED, and ni is the refractive index of a sample in which the hologram recording medium before recording is stored at a temperature of 60 C. and a relative humidity of 90% for 72 hours and then bleached with a white LED.

TABLE-US-00002 TABLE 2 Refractive Refractive Diffraction index Peak index efficiency modulation Haze variation variation (%) value (%) (%) (%) Example 1 85 0.031 0.7 1.06 0.33 Example 2 87 0.034 0.8 1.79 0.59 Example 3 85 0.033 0.7 1.06 0.20 Example 4 91 0.039 1.0 1.82 0.20 Example 5 75 0.027 0.8 1.67 0.46 Example 6 80 0.028 0.8 1.06 0.39 Example 7 80 0.030 0.8 1.06 0.39 Example 8 82 0.035 1.2 1.79 0.46 Example 9 73 0.026 0.8 1.06 0.26 Example 10 71 0.025 0.8 1.06 0.26 Example 11 75 0.030 1.8 1.48 0.43 Comparative 85 0.033 2.1 6.52 1.83 Example 1 Comparative 63 0.024 2.3 4.24 1.64 Example 2 Comparative 57 0.021 3.2 3.87 1.71 Example 3 Comparative 37 0.013 3.6 15.7 2.30 Example 4

[0271] Referring to Table 2, it is confirmed that the hologram recording media prepared in Examples 1 to 11 not only exhibit excellent diffraction efficiency, refractive index modulation value, and low haze, but also exhibit excellent reliability even after exposure to a high temperature/high humidity environment before and after recording. In contrast, the hologram recording media prepared in Comparative Examples 2 to 4 were inferior in optical recording properties, haze, and reliability in high temperature/high humidity environments. And the hologram recording medium prepared in Comparative Example 1 had excellent optical recording properties, but had high haze and exhibited poor reliability in high temperature/high humidity environments before and after recording.

[0272] Therefore, it is confirmed that when the fluorinated compound according to one embodiment of the invention is used, it is possible to provide a holographic recording medium that has excellent optical recording properties, excellent reliability even in high temperature/high humidity environments, and exhibits high transparency.