Fluorinated compound, photopolymerizable composition, hologram recording medium, method for preparing same, and optical element including same

Abstract

The invention relates to a fluorinated compound, a photopolymerizable composition, a hologram recording medium, a method for preparing the same, and an optical element including the same. The fluorinated compound is included in the photopolymerizable composition, thereby being able to provide a hologram recording medium having not only excellent optical recording characteristics but also transparent optical characteristics, and exhibiting excellent reliability even in high-temperature and high-humidity environments, and an optical element including the same.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0146091 filed in the Korean Intellectual Property Office on November 4, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0003] The present invention relates to a fluorinated compound, a photopolymerizable composition, a hologram recording medium, a method for preparing the same, and an optical element comprising the same. Background Art

[0004] The hologram recording medium records information by changing the refractive index of a hologram recording layer in the medium through an exposure process, reads the change in the refractive index in the medium thus recorded, and reproduces the information.

[0005] In this regard, the photopolymer composition can be used to prepare a hologram. The photopolymer can easily store the light interference pattern as a hologram by photopolymerization of the photoreactive monomer. Therefore, the photopolymer can be used in various fields, such as smart devices such as mobile devices, wearable display components, vehicle products (e.g., head-up displays), holographic fingerprint recognition systems, optical lenses, reflectors, deflection mirrors, filters, diffusers, diffraction elements, light guides, waveguides, holographic optical elements with projection screen and / or mask functions, optical storage systems and light diffuser plates, optical wavelength multiplexers, reflective, transmissive color filters, etc.

[0006] Specifically, a photopolymer composition for preparing a hologram comprises a polymer matrix, a photoreactive monomer, and a photoinitiator system, and a photopolymer layer prepared from such a composition is irradiated with laser interference light to cause localized photopolymerization of the monomer.

[0007] The refractive index modulation is generated by the local photopolymerization process, and the diffraction grating is generated by such refractive index modulation. The refractive index modulation value (Δn) is affected by the thickness and diffraction efficiency (DE) of the photopolymer layer, and the angular selectivity increases as the thickness decreases.

[0008] Recently, demands for development of materials capable of maintaining a stable hologram at high diffraction efficiency have increased, and various attempts have been made to prepare a photopolymer layer having high diffraction efficiency and a high refractive index modulation value and a thin thickness.

[0009] As part of such efforts, various plasticizers have been developed that can be added to photopolymer compositions. Non-reactive plasticizers with a low refractive index migrate in a different direction than photoreactive monomers with a high refractive index, while improving the formability of the photopolymer composition, thereby being able to facilitate greater refractive index modulation.

[0010] However, when various components such as plasticizers are added to the photopolymer composition, their compatibility deteriorates, which leads to problems such as degradation of basic physical properties of the hologram recording medium and turbidity of the hologram recording medium. In addition, the durability of the hologram recording medium to heat or moisture decreases, and when the hologram recording medium is applied to mobile devices or vehicle parts (such as head-up displays) that may be placed in a high temperature and high humidity environment, it also leads to a problem that deformation of the diffraction grating occurs, the image becomes distorted, and the originally intended function may not be performed.

[0011] Therefore, there is a need for the development of a new material which has excellent compatibility with the components of a hologram recording medium and which can improve the optical recording characteristics without reducing its durability against heat and moisture. Summary of the invention

[0012] Technical issues

[0013] According to one embodiment of the present invention, a fluorinated compound is provided.

[0014] According to another embodiment of the present invention, a photopolymerizable composition is provided.

[0015] According to still another embodiment of the present invention, provided are a hologram recording medium prepared from the photopolymerizable composition and a method for preparing the same.

[0016] According to another embodiment of the present invention, there is provided an optical element including the hologram recording medium.

[0017] Technical Solution

[0018] Now, a fluorinated compound, a photopolymerizable composition, a hologram recording medium, a method for preparing the same, an optical element including the same, and the like according to specific embodiments of the present invention will be described.

[0019] According to one embodiment of the present invention, there is provided a fluorinated compound represented by the following Chemical Formula 1:

[0020] [Chemical formula 1]

[0021]

[0022] Wherein, in Chemical Formula 1,

[0023] Z1 and Z 2 are each independently -O-, -S-, or -NH-,

[0024] R 1 To R 4 At least one of the fluorine-containing substituents is an alkyl group having 1 to 20 carbon atoms substituted by 2 or more fluorine groups, a cycloalkyl group having 3 to 30 carbon atoms substituted by 2 or more fluorine groups, or an aryl group having 6 to 30 carbon atoms substituted by 2 or more fluorine groups,

[0025] When R 1 To R 4 When not a fluorine-containing substituent, they are each independently 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 -CH2- of the above substituents is replaced by -O-, -S- or -NH-.

[0026] A fluorinated compound according to one embodiment of the present invention, a photopolymerizable composition including the same, a hologram recording medium formed from the photopolymerizable composition, a method for preparing the hologram recording medium, an optical element including the hologram recording medium, and the like will be described below.

[0027] The fluorinated compound according to one embodiment of the present invention has excellent properties, such as the effects produced by fluorine, such as mobility, dispersibility and antifouling properties, because the fluorine is distributed at the end of the compound. Therefore, the fluorinated compound can be used in various fields of various applications (such as plasticizers, surfactants or antifouling agents). Among them, the fluorinated compound of the above embodiment, when applied to a hologram recording medium as a plasticizer, can help improve the refractive index modulation due to its low refractive index and non-reactive properties.

[0028] In particular, the present inventors have experimentally discovered that the fluorinated compound represented by Chemical Formula 1 has excellent compatibility with other components forming a hologram recording medium and has excellent stability to heat and moisture, and thus can provide a hologram recording medium that exhibits transparent optical properties while improving optical recording properties and exhibits high reliability even in a high temperature / high humidity environment, and have completed the present invention.

[0029] In Chemical Formula 1, R 1 To R 4 At least one of is a fluorine-containing substituent. In one example, R 1It may be a fluorine-containing substituent.

[0030] The fluorine-containing substituent may be 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.

[0031] Specifically, the fluorine-containing substituent may be a linear alkyl group having 1 to 20 carbon atoms substituted with 2 or more fluorines, a cycloalkyl group having 3 to 12 carbon atoms substituted with 2 or more fluorines, or an aryl group having 6 to 14 carbon atoms substituted with 2 or more fluorines.

[0032] More specifically, the fluorine-containing substituent may be -(CH2) a (CF2) b CHF2, -(CH2) a (CF2) b CF3 or decafluorocyclohexyl. wherein a is an integer from 0 to 3, an integer from 0 to 2, or an integer from 0 to 1, and b is an integer from 0 to 19, an integer from 0 to 15, an integer from 0 to 14, an integer from 0 to 13, an integer from 0 to 12, or an integer from 0 to 11.

[0033] In one example, the fluorine-containing substituent may be -(CH2) a (CF2) b CHF2, -(CH2) a (CF2) b CF3, or decafluorocyclohexyl.

[0034] When R in Formula 1 1 To R 4 When it is not a fluorine-containing substituent, R 1 To R 4 Each is independently 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 may be a substituent in which at least one -CH2- of the above substituents is replaced by -O-, -S- or -NH-.

[0035] Specifically, when R in Chemical Formula 1 1 To R 4 When it is not a fluorine-containing substituent, R 1 To R 4Each of the above groups may be independently a linear 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, a heteroaryl group having 4 to 12 carbon atoms, an arylalkyl group having 7 to 16 carbon atoms, or -(R 5 -Y 1 ) c -R 6 . In -(R 5 -Y 1 ) c -R 6 In, R 5 is an alkylene group having 1 to 6 carbon atoms, R 6 is an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms, Y 1 is -O- or -S-, and c may be an integer from 1 to 12, provided that when c is 2 or greater, R 5 May be the same as or different from each other.

[0036] More specifically, when R in Chemical Formula 1 1 To R 4 When it is not a fluorine-containing substituent, R 1 To R 4 Each is independently ethyl, propyl, butyl, pentyl, hexyl, phenyl, benzyl, pyridyl, pyrimidyl, methoxymethyl, methoxyethyl, methylmercaptoethyl, methylaminoethyl, -(CH2CH2O) c1 CH3, -CH2O(CH2CH2O) c2 CH3, cyclohexyloxyethyl, cyclohexylmercaptoethyl, or phenyloxyethyl, wherein c1 is an integer from 1 to 5, and c2 is an integer from 1 to 4.

[0037] The fluorinated compound represented by Chemical Formula 1 may include at least one fluorinated compound selected from the group consisting of fluorinated compounds represented by the following Chemical Formulas 1-1 to 1-9.

[0038] [Chemical formula 1-1]

[0039]

[0040] Among them, in chemical formula 1-1,

[0041] Z a1 and Z b1 are each independently -O-, -S-, or -NH-,

[0042] R a1 and R b1 Each independently is CF3 or CHF2,

[0043] R c1 and R c2 are each independently an alkylene group having 1 to 6 carbon atoms,

[0044] Y a1 and Y a2 are each independently -CH2-, -O-, -S-, or -NH-,

[0045] R d1 and R d2 are each independently an alkylene group having 1 to 4 carbon atoms,

[0046] R e1 and R e2 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group,

[0047] p1 and p2 are each independently an integer from 0 to 9, and q1 and q2 are each independently an integer from 0 to 3,

[0048] [Chemical formula 1-2]

[0049]

[0050] Wherein, in Chemical Formula 1-2,

[0051] Z a2 and Z b2 are each independently -O-, -S-, or -NH-,

[0052] R a2 is CF3 or CHF2,

[0053] R c3 To R c5 are each independently an alkylene group having 1 to 6 carbon atoms,

[0054] Y a3 To Y a5 are each independently -CH2-, -O-, -S-, or -NH-,

[0055] R d3 To R d5 are each independently an alkylene group having 1 to 4 carbon atoms,

[0056] R e3 To R e5 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group,

[0057] p3 is an integer from 0 to 9, and q3 to q5 are each independently an integer from 0 to 3,

[0058] [Chemical formula 1-3]

[0059]

[0060] Wherein, in chemical formula 1-3,

[0061] Z a3 and Z b3 are each independently -O-, -S-, or -NH-,

[0062] R a3 , R b2 and R b3 Each independently is CF3 or CHF2,

[0063] R c6 is an alkylene group having 1 to 6 carbon atoms,

[0064] Y a6 is -CH2-, -O-, -S-, or -NH-,

[0065] R d6 is an alkylene group having 1 to 4 carbon atoms,

[0066] R e6 is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group,

[0067] R f1 and R f2 are each independently hydrogen or fluorine, and

[0068] p4 to p6 are each independently an integer from 0 to 9, and q6 is an integer from 0 to 3,

[0069] [Chemical formula 1-4]

[0070]

[0071] Wherein, in chemical formula 1-4,

[0072] Z a4 and Z b4 are each independently -O-, -S-, or -NH-,

[0073] R a4 , R a5 , R b4 and R b5 Each independently is CF3 or CHF2,

[0074] R f3 To R f6 are each independently hydrogen or fluorine, and

[0075] p7 to p10 are each independently an integer from 0 to 9,

[0076] [Chemical formula 1-5]

[0077]

[0078] Wherein, in chemical formula 1-5,

[0079] Z a5 and Z b5 are each independently -O-, -S-, or -NH-,

[0080] R a6 and R a7 Each independently is CF3 or CHF2,

[0081] R c7 and R c8 are each independently an alkylene group having 1 to 6 carbon atoms,

[0082] Y a7 and Y a8 are each independently -CH2-, -O-, -S-, or -NH-,

[0083] R d7 and R d8 are each independently an alkylene group having 1 to 4 carbon atoms,

[0084] R e7 and R e8 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group,

[0085] p11 to p12 are each independently an integer from 0 to 9, and q7 and q8 are each independently an integer from 0 to 3,

[0086] [Chemical formula 1-6]

[0087]

[0088] Wherein, in chemical formula 1-6,

[0089] Z a6 and Z b6 are each independently -O-, -S-, or -NH-,

[0090] R a8 To R a10 Each independently is CF3 or CHF2,

[0091] R c9 is an alkylene group having 1 to 6 carbon atoms,

[0092] Ya9 is -CH2-, -O-, -S-, or -NH-,

[0093] R d9 is an alkylene group having 1 to 4 carbon atoms,

[0094] R e9 is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group,

[0095] p13 to p15 are each independently an integer from 0 to 9, and q9 is an integer from 0 to 3,

[0096] [Chemical formula 1-7]

[0097]

[0098] Wherein, in Chemical Formula 1-7,

[0099] Z a7 and Z b7 are each independently -O-, -S-, or -NH-, and

[0100] R b9 , R c10 and R d10 are each independently decafluorocyclohexyl, phenyl, pyridyl, pyrimidinyl, or methoxyethyl,

[0101] [Chemical formula 1-8]

[0102]

[0103] Wherein, in Chemical Formula 1-8,

[0104] Z a8 and Z b8 are each independently -O-, -S-, or -NH-, and

[0105] R b10 , R c11 and R d11 are each independently 2,2,3,3,4,4,5,5-octafluoro-1-pentyl, decafluorocyclohexyl, phenyl, or methoxyethyl,

[0106] [Chemical formula 1-9]

[0107]

[0108] Wherein, in Chemical Formula 1-9,

[0109] Z a9 and Z b9 are each independently -O-, -S-, or -NH-,

[0110] R a11 and R b11 Each independently is CF3 or CHF2,

[0111] R c12 and R d12 are each independently phenyl or benzyl, and

[0112] p16 and p17 are each independently an integer of 0 to 9.

[0113] On the other hand, according to another embodiment of the present invention, there is provided a photopolymerizable composition comprising: a fluorinated compound; a polymer matrix or a precursor thereof; a photoreactive monomer; and a photoinitiator system.

[0114] The fluorinated compound is a fluorinated compound represented by the above Chemical Formula 1, and a detailed description thereof is omitted here.

[0115] The photopolymerizable composition can be used in various technical fields. In one example, the photopolymerizable composition can be used as a photopolymer composition for forming a hologram recording medium.

[0116] Next, an example in which the photopolymerizable composition is used as a photopolymer composition for forming a hologram recording medium will be described in detail.

[0117] The photopolymer composition comprises a polymer matrix or a precursor thereof, which serves as a support for a photopolymer layer formed from the photopolymer composition.

[0118] The polymer matrix is ​​formed by cross-linking a siloxane-based polymer containing a silane functional group (Si-H) and a (meth) acrylic polyol. Specifically, the polymer matrix is ​​formed by cross-linking a (meth) acrylic polyol with a siloxane-based polymer containing a silane functional group. More specifically, the hydroxyl group of the (meth) acrylic polyol can form a crosslink with the silane functional group of the siloxane-based polymer through a hydrosilylation reaction. The hydrosilylation reaction can proceed rapidly even at room temperature (e.g., a temperature in the range of about 15°C to 30°C, which is a temperature without heating or cooling) under a Pt-based catalyst. Therefore, the photopolymer composition adopts a polymer matrix that can be quickly cross-linked even at room temperature as a support, thereby being able to improve the preparation efficiency and productivity of the hologram recording medium.

[0119] The polymer matrix can enhance the mobility of components (e.g., photoreactive monomers or plasticizers, etc.) contained in the photopolymer layer due to the flexible main chain of the siloxane-based polymer. In addition, the siloxane bond having excellent heat resistance and wet heat resistance characteristics can help ensure the reliability of the photopolymer layer recording optical information and the hologram recording medium including the same.

[0120] The polymer matrix can have a relatively low refractive index, which can be used to enhance the refractive index modulation of the layer formed by the photopolymer composition. For example, the upper limit of the refractive index of the polymer matrix can be 1.53 or less, 1.52 or less, 1.51 or less, 1.50 or less, or 1.49 or less. In addition, the lower limit of the refractive index of the polymer matrix can be, for example, 1.40 or greater, 1.41 or greater, 1.42 or greater, 1.43 or greater, 1.44 or greater, 1.45 or greater, or 1.46 or greater. As used herein, "refractive index" can be a value measured at 25°C using an Abbe refractometer.

[0121] The photopolymer composition may include the polymer matrix in a cross-linked form as described above, or may include a precursor thereof. When the photopolymer composition includes a precursor of the polymer matrix, it may include a siloxane-based polymer, a (meth)acrylic polyol, and a Pt-based catalyst.

[0122] The siloxane-based polymer may include, for example, a repeating unit represented by the following Chemical Formula 2 and a terminal group represented by the following Chemical Formula 3.

[0123] [Chemical formula 2]

[0124]

[0125] Wherein, in Chemical Formula 2,

[0126] Plural R 11 and R 12 are the same as or different from each other and are each independently hydrogen, halogen, or an alkyl group having 1 to 10 carbon atoms, and

[0127] k is an integer from 1 to 10,000,

[0128] [Chemical formula 3]

[0129]

[0130] Among them, in chemical formula 3,

[0131] Plural R 13 To R 15 are the same as or different from each other and are each independently hydrogen, halogen, or an alkyl group having 1 to 10 carbon atoms, and

[0132] R is selected from at least one repeating unit among the repeating units represented by Chemical Formula 2 and any one terminal group among the terminal groups represented by Chemical Formula 3. 11 To R 15 At least one of them is hydrogen.

[0133] In Chemical Formula 3, -(O)- means that when Si of the terminal group represented by Chemical Formula 3 is bonded to the repeating unit represented by Chemical Formula 2, it is bonded through oxygen (O) or directly bonded without oxygen (O).

[0134] As used herein, "alkyl" can be a straight chain alkyl, a branched chain alkyl, or a cyclic alkyl. As non-limiting examples, "alkyl" as used herein can be methyl, ethyl, propyl (e.g., n-propyl, isopropyl, etc.), butyl (e.g., n-butyl, isobutyl, tert-butyl, sec-butyl, cyclobutyl, etc.), pentyl (e.g., n-pentyl, isopentyl, neopentyl, tert-pentyl, 1,1-dimethyl-propyl, 1-ethyl-propyl, 1-methyl-butyl, cyclopentyl, etc.), hexyl (e.g., n-hexyl, 1-methylpentyl, 2-methylpentyl, etc.), cyclopentyl, etc.), cyclopentyl, etc.), methyl butyl, propyl, 1-ethyl-propyl, 1-methyl-butyl, cyclopentyl, etc.), methyl butyl, propyl, 1-methyl-butyl, 1-methyl-pentyl, 1-methyl-butyl ... The invention also includes but is not limited to cyclopentyl, 4-methylpentyl, 3,3-dimethylbutyl, 1-ethyl-butyl, 2-ethylbutyl, cyclopentylmethyl, cyclohexyl, etc.), heptyl (for example, n-heptyl, 1-methylhexyl, 4-methylhexyl, 5-methylhexyl, cyclohexylmethyl, etc.), octyl (for example, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, etc.), nonyl (for example, n-nonyl, 2,2-dimethylheptyl, etc.), and the like.

[0135] In one example, R in Chemical Formula 2 and Chemical Formula 3 11 To R 15 is methyl or hydrogen, and R 11 To R 15 At least two of them may be hydrogen. More specifically, the siloxane-based polymer may be one in which R 11 and R 12 are each independently methyl and hydrogen, and R 13 To R 15 A compound in which each independently is a methyl group or a hydrogen group (for example, a polymethylhydrogensiloxane whose terminal group is a trimethylsilyl group or a dimethylhydrogensilyl group); wherein some R 11 and R 12 are methyl and hydrogen respectively, and the remaining R 11 and R 12 are all methyl groups, and R 13 To R 15 A compound in which each independently is a methyl group or a hydrogen group (for example, a poly(dimethylsiloxane-co-methylhydrogensiloxane) whose terminal group is a trimethylsilyl group or a dimethylhydrogensilyl group); or a compound in which R 11 and R 12 Both are methyl groups. R 13 To R 15A compound in which at least one of the terminal groups is hydrogen and the others are each independently methyl or hydrogen (for example, a polydimethylsiloxane in which either or both of the terminal groups are dimethylhydrogensilyl groups).

[0136] As an example, the number average molecular weight (Mn) of the siloxane-based compound may be in the range of 200 to 4,000. Specifically, the lower limit of the number average molecular weight of the siloxane-based polymer may be, for example, 200 or more, 250 or more, 300 or more, or 350 or more, and the upper limit thereof may be, for example, 3,500 or less, 3,000 or less, 2,500 or less, 2,000 or less, 1,500 or less, or 1,000 or less. When the number average molecular weight of the siloxane-based polymer satisfies the above range, the following problems can be prevented, thereby making the hologram recording medium formed by the photopolymer composition exhibit excellent optical recording characteristics and excellent durability under high temperature / high humidity conditions: during the crosslinking process with (meth) acrylic polyol at room temperature or higher, the siloxane-based polymer volatilizes and the matrix crosslinking degree decreases, or the siloxane-based polymer has poor compatibility with other components of the photopolymer composition, and thus phase separation occurs between the components.

[0137] The number average molecular weight means the number average molecular weight (unit: g / mol) according to polystyrene determined by the GPC method. In the process of determining the number average molecular weight according to polystyrene measured by the GPC method, known analytical devices, detectors such as refractive index detectors and analytical columns can be used, and commonly used temperature, solvent and flow conditions can be used. Specific examples of measurement conditions can include a temperature of 25° C., a tetrahydrofuran solvent, and a flow rate of 1 mL / min.

[0138] (Meth) acrylic polyol may refer to a polymer in which one or more, specifically two or more, hydroxyl groups are bonded to the main chain or side chain of a (meth) acrylate-based polymer. Unless otherwise specifically stated, "(meth) acrylic" as used herein refers to acrylic and / or methacrylic, which is a term covering all acrylics, methacrylics, or mixtures of acrylics and methacrylics.

[0139] The (meth) acrylic polyol is a homopolymer of a (meth) acrylate-based monomer having a hydroxyl group, a copolymer of two or more types of (meth) acrylate-based monomers having a hydroxyl group, or a copolymer of a (meth) acrylate-based monomer having a hydroxyl group and a (meth) acrylate-based monomer not having a hydroxyl group. Unless otherwise specified, "copolymer" as used herein is a term covering all random copolymers, block copolymers, and graft copolymers.

[0140] The (meth)acrylate-based monomer having a hydroxyl group may include, for example, hydroxyalkyl (meth)acrylate, hydroxyaryl (meth)acrylate, etc., the alkyl group is an alkyl group having 1 to 30 carbon atoms, and the aryl group may be an aryl group having 6 to 30 carbon atoms. In addition, the (meth)acrylate-based monomer not having a hydroxyl group may include, for example, a (meth)acrylate-based monomer, a (meth)acrylate-based monomer, etc., the alkyl group may be an alkyl group having 1 to 30 carbon atoms, and the aryl group may be an aryl group having 6 to 30 carbon atoms.

[0141] As an example, the weight average molecular weight (Mw) of (meth) acrylic polyol can be in the range of 150,000 to 1,000,000. The weight average molecular weight means the weight average molecular weight according to polystyrene measured by the GPC method as described above. For example, the lower limit of the weight average molecular weight can be 150,000 or more, 200,000 or more, or 250,000 or more, and its upper limit can be, for example, 900,000 or less, 850,000 or less, 800,000 or less, 750,000 or less, 700,000 or less, 650,000 or less, 600,000 or less, 550,000 or less, 500,000 or less, or 450,000 or less. When the weight average molecular weight of the (meth)acrylic polyol satisfies the above range, the polymer matrix fully exerts its function as a support, and therefore the recording properties of optical information are less reduced even after the use time has passed, and sufficient flexibility is imparted to the polymer matrix, thereby being able to improve the mobility of components contained in the photopolymer composition (for example, photoreactive monomers or plasticizers, etc.) and minimize the reduction in the recording properties of optical information.

[0142] In order to adjust the crosslinking density of the (meth)acrylic polyol through the siloxane-based polymer to a level conducive to ensuring the function of the hologram recording medium, the hydroxyl equivalent of the (meth)acrylic polyol may be adjusted to an appropriate level.

[0143] Specifically, the hydroxyl (-OH) equivalent of the (meth) acrylic polyol may be, for example, in the range of 500 g / equivalent to 3000 g / equivalent. More specifically, the lower limit of the hydroxyl (-OH) equivalent of the (meth) acrylic polyol may be 600 g / equivalent or more, 700 g / equivalent or more, 800 g / equivalent or more, 900 g / equivalent or more, 1000 g / equivalent or more, 1100 g / equivalent or more, 1200 g / equivalent or more, 1300 g / equivalent or more, 1400 g / equivalent or more, 1500 g / equivalent or more, 1600 g / equivalent or more, 1700 g / equivalent or more, or 1750 g / equivalent or more. In addition, the upper limit of the hydroxyl (-OH) equivalent of (meth) acrylic polyol can be 2900g / equivalent or less, 2800g / equivalent or less, 2700g / equivalent or less, 2600g / equivalent or less, 2500g / equivalent or less, 2400g / equivalent or less, 2300g / equivalent or less, 2200g / equivalent or less, 2100g / equivalent or less, 2000g / equivalent or less, or 1900g / equivalent or less. The hydroxyl (-OH) equivalent of (meth) acrylic polyol is the equivalent (g / equivalent) of one hydroxyl functional group, which is the value obtained by dividing the weight average molecular weight of (meth) acrylic polyol by the number of hydroxyl functional groups per molecule. As the equivalent value is smaller, the functional group density is higher, and as the equivalent value is larger, the functional group density is smaller. When the hydroxyl (-OH) equivalent of the (meth) acrylic polyol satisfies the above range, the polymer matrix has an appropriate cross-linking density and thus fully serves as a support, and the mobility of the components contained in the layer formed by the photopolymer composition is improved, which allows the initial refractive index modulation value to be maintained at an excellent level even over time without the problem of boundary surface collapse of the diffraction grating generated after recording, thereby minimizing the reduction in the recording characteristics of the optical information.

[0144] For example, the glass transition temperature (Tg) of the (meth) acrylic polyol may be in the range of -60°C to -10°C. Specifically, the lower limit of the glass transition temperature may be, for example, -55°C or higher, -50°C or higher, -45°C or higher, -40°C or higher, -35°C or higher, -30°C or higher, or -25°C or higher, and the upper limit thereof may be, for example, -15°C or lower, -20°C or lower, -25°C or lower, -30°C or lower, or -35°C or lower. If the above glass transition temperature range is met, the glass transition temperature may be reduced without significantly reducing the modulus of the polymer matrix, thereby increasing the mobility (fluidity) of other components in the photopolymer composition, and also improving the formability of the photopolymer composition. The glass transition temperature may be measured using known methods such as DSC (Differential Scanning Calorimetry) or DMA (dynamic mechanical analysis).

[0145] The refractive index of the (meth) acrylic polyol may be, for example, 1.40 or more and less than 1.50. Specifically, the lower limit of the refractive index of the (meth) acrylic polyol may be, for example, 1.41 or more, 1.42 or more, 1.43 or more, 1.44 or more, 1.45 or more, or 1.46 or more, and the upper limit thereof may be, for example, 1.49 or less, 1.48 or less, 1.47 or less, 1.46 or less, or 1.45 or less. When the (meth) acrylic polyol has a refractive index within the above range, it may contribute to improving the refractive index modulation. The refractive index of the (meth) acrylic polyol is a theoretical refractive index and may be calculated using the refractive index of the monomer used to prepare the (meth) acrylic polyol (value measured at 25° C. using an Abbe refractometer) and the fraction (molar ratio) of each monomer.

[0146] (Meth) acrylic polyol and siloxane-based polymer can be used to make the molar ratio (SiH / OH) of the silane functional group (Si-H) of the siloxane-based polymer and the hydroxyl group (-OH) of the (meth) acrylic polyol be 0.80 to 3.5. That is, the type and content of the siloxane-based polymer and the (meth) acrylic polyol can be selected so that the molar ratio is met when forming the polymer matrix. The lower limit of the molar ratio (SiH / OH) can be, for example, 0.81 or greater, 0.85 or greater, 0.90 or greater, 0.95 or greater, 1.00 or greater, or 1.05 or greater, and its upper limit can be, for example, 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, 3.05 or less, or 3.0 or less. When the above molar ratio (SiH / OH) range is met, the polymer matrix is ​​cross-linked into an appropriate cross-linking density, so that the reliability under high temperature / high humidity conditions is improved, and sufficient refractive index modulation values ​​can be achieved.

[0147] The Pt-based catalyst may be, for example, a Karstedt catalyst, etc. In addition to the Pt-based catalyst, the precursor of the polymer matrix may optionally include a rhodium-based catalyst, an iridium-based catalyst, a rhenium-based catalyst, a molybdenum-based catalyst, an iron-based catalyst, a nickel-based catalyst, an alkali metal or alkaline earth metal-based catalyst, a Lewis acid-based catalyst or a carbene-based non-metal catalyst.

[0148] On the other hand, a hologram recording medium can be prepared by irradiating an object light and a reference light onto a photopolymer layer formed by a photopolymer composition. Due to the interference field between the object light and the reference light, photopolymerization of the photoreactive monomer does not occur in the destructive interference region, but photopolymerization of the photoreactive monomer occurs in the constructive interference region. As the photoreactive monomer is continuously consumed in the constructive interference region, a concentration difference occurs between the photoreactive monomers in the destructive interference region and the constructive interference region, and therefore, the photoreactive monomers in the destructive interference region diffuse into the constructive interference region. A diffraction grating is generated by the refractive index modulation thus generated.

[0149] Therefore, the photoreactive monomer may include a compound having a higher refractive index than the polymer matrix to achieve the above-mentioned refractive index modulation. However, all photoreactive monomers included in the photopolymer composition are not limited to those having a higher refractive index than the polymer matrix, and at least a portion of the photoreactive monomers may have a higher refractive index than the polymer matrix to achieve a high refractive index modulation value. In one example, the photoreactive monomer may include a monomer having a refractive index of 1.50 or greater, 1.51 or greater, 1.52 or greater, 1.53 or greater, 1.54 or greater, 1.55 or greater, 1.56 or greater, 1.57 or greater, 1.58 or greater, 1.59 or greater, or 1.60 or greater and 1.70 or less.

[0150] The photoreactive monomer may include at least one monomer selected from a monofunctional monomer having one photoreactive functional group and a multifunctional monomer having two or more photoreactive functional groups. The photoreactive functional group may be, for example, a (meth)acryloyl group, a vinyl group, a thiol group, etc. More specifically, the photoreactive functional group may be a (meth)acryloyl group.

[0151] The monofunctional monomer may include, for example, at least one selected from the group consisting of benzyl (meth)acrylate (M1182 with a refractive index of 1.5140, Miwon Specialty Chemical), benzyl 2-phenylacrylate, phenoxybenzyl (meth)acrylate (M1122 with a refractive index of 1.565, Miwon Specialty Chemical), phenol (ethylene oxide) (meth)acrylate (phenol (EO) (meth)acrylate; M140 with a refractive index of 1.516, Miwon Specialty Chemical), phenol (ethylene oxide) 2 (meth)acrylate (phenol (EO) 2 (meth)acrylate; M142 with a refractive index of 1.510, Miwon Specialty Chemical), o-phenylphenol (ethylene oxide) (meth)acrylate (o-phenylphenol (EO) (meth)acrylate; M1142 with a refractive index of 1.577, Miwon Specialty Chemical), phenylthioethyl (meth)acrylate (M1162 with a refractive index of 1.560, Miwon Specialty Chemical), Specialty Chemical), and biphenyl methyl (meth)acrylate.

[0152] The multifunctional monomer may include, for example, at least one selected from the following: bisphenol A (ethylene oxide) 2～10 Di(meth)acrylate (bisphenol A (EO) 2～10(Meth)acrylates; M240 with a refractive index of 1.537, M241 with a refractive index of 1.529, M244 with a refractive index of 1.545, M245 with a refractive index of 1.537, M249 with a refractive index of 1.542, M2100 with a refractive index of 1.516, M2101 with a refractive index of 1.512, Miwon Specialty Chemical), bisphenol A epoxy di(meth)acrylate (PE210 with a refractive index of 1.557, PE2120A with a refractive index of 1.533, PE2120B with a refractive index of 1.534, PE2020C with a refractive index of 1.539, PE2120S with a refractive index of 1.556, Miwon Specialty Chemical), Chemical), bisphenol fluorene di(meth)acrylate (HR6022 with a refractive index of 1.600, HR6040 with a refractive index of 1.600, HR6042 with a refractive index of 1.600, Miwon Specialty Chemical), modified bisphenol fluorene di(meth)acrylate (HR6060 with a refractive index of 1.584, HR6100 with a refractive index of 1.562, HR6200 with a refractive index of 1.530, Miwon Specialty Chemical), tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate (M370 with a refractive index of 1.508, Miwon Specialty Chemical), phenol novolac epoxy (meth)acrylate (SC6300 with a refractive index of 1.525, Miwon Specialty Chemical), Chemical), and cresol novolac epoxy (meth)acrylate (SC6400 with a refractive index of 1.522, SC6400C with a refractive index of 1.522, Miwon Specialty Chemical).

[0153] Based on the polymer matrix of 100 weight parts, the photopolymer composition can include the photoreactive monomer with the amount of 50 weight parts to 300 weight parts. For example, the lower limit of the content of the photoreactive monomer can be 50 weight parts or more, 60 weight parts or more, 70 weight parts or more, 80 weight parts or more or 90 weight parts or more, and its upper limit can be 300 weight parts or less, 280 weight parts or less, 250 weight parts or less, 220 weight parts or less, 200 weight parts or less, 190 weight parts or less or 180 weight parts or less. When meeting the above scope, it is conducive to ensure excellent optical recording characteristics and durability in high temperature / high humidity environment.

[0154] The content of the polymer matrix herein means the total content (weight) of the (meth) acrylic polyol and the siloxane-based polymer forming the matrix. In other words, the content of the polymer matrix means both the content of the polymer matrix formed by crosslinking the (meth) acrylic polyol and the siloxane-based polymer and the content of the partially uncrosslinked polymer matrix precursor.

[0155] The photopolymer composition comprises a photoinitiator system. The photoinitiator system may mean a photoinitiator, or a combination of a photosensitizer and a co-initiator that enables polymerization initiated by light.

[0156] The photopolymer composition may comprise a photosensitizer and a co-initiator as a photoinitiator system.

[0157] As the photosensitizer, for example, a photosensitizing dye can be used. Specifically, the photosensitizing dye may include, for example, at least one selected from the following: a silicon rhodamine compound, anthraquinone (9,1-bc) naphthane (3,2,1-kl)

[0158] Sulfonium derivatives of ceramidonine, new methylene blue, thioerythrosine triethylammonium, 6-acetylamino-2-methylceramidonin, eosin, erythrosine, rose bengal, thionine, basic yellow, chlorinated pinacol cyanol, rhodamine 6G, calocyanine, ethyl violet, Victoria Blue R, azure blue, quinaldine red, crystal violet, brilliant green, Astrazon Orange G, darrow red, pyronin Y, basic red 29, pyranose I (pyran Iodide), Safranin O, Cyanine, Methylene Blue, Azure A, and BODIPY.

[0159] In one example, as the photosensitizing dye, cyanine dyes Cy3 and Cy5 (H-Nu640, SpectraGroup Limited) may be used, or Safranin O may be used.

[0160] Based on 100 parts by weight of the polymer matrix, the photopolymer composition can include photosensitizer dyes in the range of 0.01 parts by weight to 10 parts by weight. Specifically, the lower limit of the content of photosensitizer dyes can be, for example, 0.05 parts by weight or more, 0.07 parts by weight or more, or 0.10 parts by weight or more, and its upper limit can be, for example, 5 parts by weight or less. When the above range is met, it is conducive to showing a suitable polymerization reaction rate and ensuring the desired optical recording characteristics.

[0161] The coinitiator may be an electron donor, an electron acceptor, or a mixture thereof.

[0162] In one example, the photopolymer composition according to one embodiment of the present invention may include an electron donor as a coinitiator. The electron donor may include, for example, a borate anion represented by the following Chemical Formula 4.

[0163] [Chemical formula 4]

[0164] BX 1 X 2 X 3 X 4

[0165] Wherein, in chemical formula 4, X 1 To X 4 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, an alkylaryl group having 7 to 30 carbon atoms, or an allyl group, provided that X 1 To X 4 At least one of the groups is not an aryl group.

[0166] When an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, an alkylaryl group having 7 to 30 carbon atoms, or an allyl group is substituted, it may be substituted with at least one selected from halogen and an alkoxy group having 1 to 5 carbon atoms.

[0167] Specifically, X 1 To X 3 may be each independently halogen-substituted or unsubstituted methyl, ethyl, propyl, n-butyl, n-pentyl, n-hexyl, cyclobutyl, cyclopentyl, cyclohexyl, vinyl, propenyl, phenyl, methylphenyl, methoxyphenyl, naphthyl, methylnaphthyl, or methoxynaphthyl, and X 4 It may be an n-butyl group, an n-pentyl group, or an n-hexyl group. More specifically, the borate anion represented by Chemical Formula 4 may be, for example, a triphenylbutylborate anion.

[0168] The cation bonded to the borate anion is a cation that does not absorb light, and may be an alkali metal cation or a quaternary ammonium cation. A quaternary ammonium cation means an ammonium cation in which nitrogen (N) is substituted with four substituents, wherein the four substituents are each independently an alkyl group having 1 to 40 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 6 to 40 carbon atoms, or an alkyl group having 2 to 40 carbon atoms connected by an ester bond (e.g., -CH2CH2-O-CO-CH2CH2CH3, etc.).

[0169] As the electron donor, for example, commercially available butyrylcholine triphenylbutylborate (Borate V, manufactured by Spectra Group) can be used.

[0170] In one example, the photopolymer composition may include an electron acceptor as a co-initiator. The electron acceptor may include, for example, Salts, such as sulfonium salts, iodine salt, or a mixture thereof.

[0171] In one example, the electron acceptor may include iodine As the electron acceptor, for example, commercially available H-Nu 254 (Spectra Group) can be used.

[0172] Based on 100 parts by weight of the polymer matrix, the photopolymer composition may contain the co-initiator in a range of 0.05 to 10 parts by weight. Specifically, the lower limit of the content of the co-initiator may be, for example, 0.1 parts by weight or more, 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more, and the upper limit thereof may be, for example, 5 parts by weight or less. When the above range is met, it is beneficial to exhibit an appropriate polymerization reaction rate and ensure desired optical recording properties.

[0173] The photoinitiator system may contain an additional photoinitiator to remove the color of the photosensitive dye and react all unreacted photoreactive monomers after the light irradiation for recording. The photoinitiator may include, for example, imidazole derivatives, bisimidazole derivatives, N-arylglycine derivatives, organic azide compounds, titanocene, aluminate complexes, organic peroxides, N-alkoxypyridines, Onium salts, thioxanthone derivatives, amine derivatives, diazonium salts, sulfonium salts, iodine Salts, sulfonates, imide sulfonates, dialkyl-4-hydroxysulfonium salts, arylsulfonic acid p-nitrobenzyl esters, silanol-aluminum complexes, (η6-phenyl)(η5-cyclopentadienyl) iron (II), benzoin toluenesulfonate / salt, 2,5-dinitrobenzyl toluenesulfonate / salt, N-toluenesulfonylphthalic acid imide, or mixtures thereof, etc. More specifically, the photoinitiator may include 1,3-di(tert-butyldioxycarbonyl)benzophenone, 3,3',4,4"-tetra(tert-butyldioxycarbonyl)benzophenone, 3-phenyl-5-isobutylenesulfonate, 1,3-di(tert-butyldioxycarbonyl)benzophenone, 1,3',4,4"-tetra ... oxazolidinone, 2-mercaptobenzimidazole, bis(2,4,5-triphenyl)imidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one (product name: Irgacure 651 / manufacturer: BASF), 1-hydroxy-cyclohexyl-phenyl-ketone (product name: Irgacure 184 / manufacturer: BASF), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (product name: Irgacure 369 / manufacturer: BASF), bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium (product name: Irgacure 784 / manufacturer: BASF), Ebecryl P-115 (manufacturer: SK Entis), Cyracure UVI-6970, Cyracure UVI-6974, Cyracure UVI-6990 (manufacturer: Dow Chemical Co., USA), Irgacure 264, Irgacure 250 (manufacturer: BASF), CIT-1682 (manufacturer: Nippon Soda), or a mixture thereof, but not limited thereto.

[0174] The photopolymer composition includes a fluorinated compound as a plasticizer. The fluorinated compound is a fluorinated compound represented by Chemical Formula 1, and a detailed description thereof is omitted herein.

[0175] Plasticizers make it easier to achieve refractive index modulation during the preparation of hologram recording media. More specifically, plasticizers reduce the glass transition temperature of the polymer matrix, improve the mobility of photoreactive monomers, and have low refractive index and non-reactive properties. Therefore, when the photoreactive monomers uniformly distributed in the polymer matrix but not photopolymerized move, they can move in the opposite direction of the plasticizer and contribute to refractive index modulation. In addition, plasticizers can also help improve the formability of the photopolymer composition.

[0176] The fluorinated compound may have a low refractive index of 1.45 or less to perform the above-mentioned plasticizer function. Specifically, the upper limit of the refractive index may be, for example, 1.44 or less, 1.43 or less, 1.42 or less, 1.41 or less, 1.40 or less, 1.40 or less, 1.39 or less, 1.38 or less, or 1.37 or less, and the lower limit of the refractive index may be, for example, 1.30 or more, 1.31 or more, 1.32 or more, 1.33 or more, 1.34 or more, or 1.35 or more. Due to the use of a fluorinated compound having a lower refractive index than the above-mentioned photoreactive monomer, the refractive index of the polymer matrix can be further reduced, and the refractive index modulation of the photoreactive monomer can be made greater.

[0177] When the photopolymer composition includes the fluorinated compound represented by Chemical Formula 1, a hologram recording medium having excellent optical recording characteristics and having excellent reliability and high transparency even in a high temperature / high humidity environment may be provided.

[0178] More specifically, the fluorinated compound represented by Chemical Formula 1 exhibits a sufficiently low refractive index, and thus can fully function as a basic plasticizer to increase the refractive index modulation of the photoreactive monomer and improve the dispersibility of the components in the photopolymer composition. In addition, the fluorinated compound represented by Chemical Formula 1 is less likely to migrate to the surface of the photopolymer layer even in a high temperature and high humidity environment, is heat-resistant and moisture-resistant, and is not easily decomposed even under high temperature / high humidity conditions, thereby being able to improve reliability in a high temperature / high humidity environment. In addition, the fluorinated compound represented by Chemical Formula 1 exhibits excellent compatibility with a component having a high refractive index, and can ensure highly transparent optical properties due to excellent moisture and heat resistance.

[0179] In Chemical Formula 1, when the fluorine-containing substituent is, for example, -(CH2) a (CF2) b CHF2, -(CH2) a (CF2) b When CF3 or decafluorocyclohexyl is used, a hologram recording medium having low haze can be provided while contributing to improving refractive index modulation.

[0180] Based on 100 parts by weight of the polymer matrix, the photopolymer composition can include the fluorinated compound in an amount of 20 to 200 parts by weight. Specifically, the lower limit of the content of the fluorinated compound can be, for example, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, 40 parts by weight or more, 45 parts by weight or more, 50 parts by weight or more, or 55 parts by weight or more, and its upper limit can be, for example, 200 parts by weight or less, 180 parts by weight or less, 150 parts by weight or less, 120 parts by weight or less, or 100 parts by weight or less. When the above range is met, it can show a large refractive index modulation value after recording due to the fluorinated compound having a sufficiently low refractive index, without deteriorating the compatibility with the components contained in the photopolymer composition, some fluorinated compounds flowing out to the surface of the photopolymer layer or deteriorating the haze, which is conducive to ensuring excellent optical recording characteristics.

[0181] The photopolymer composition may also contain additives such as defoamers.

[0182] The photopolymer composition may contain a silicone-based reactive additive as a defoamer. As a silicone-based reactive additive, for example, a commercial product such as Tego Rad 2500 may be used.

[0183] The content of the additive (eg, defoaming agent) may be appropriately adjusted to a level that does not interfere with the function of the hologram recording medium.

[0184] The photopolymer composition may further comprise a solvent.

[0185] The solvent may be an organic solvent, and examples thereof may be at least one organic solvent selected from ketones, alcohols, acetates, and ethers, but are not limited thereto. Specific examples of such organic solvents include at least one selected from the following: ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, or isobutyl ketone; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, or tert-butanol; acetates such as ethyl acetate, isopropyl acetate, or polyethylene glycol monomethyl ether acetate; and ethers such as tetrahydrofuran or propylene glycol monomethyl ether.

[0186] The organic solvent may be added at a point in time when the respective components contained in the photopolymer composition are mixed, or it may be added after the respective components are added in a state of being dispersed or mixed in the organic solvent and then contained in the photopolymer composition.

[0187] Photopolymer composition can include solvent so that solid content concentration is 1 wt % to 90 wt %. Specifically, photopolymer composition can include solvent so that solid concentration is 20 wt % or more, 30 wt % or more, 50 wt % or more, or 60 wt % or more and 85 wt % or less, 80 wt % or less, 75 wt % or less, or 70 wt % or less. Within the scope, photopolymer composition shows suitable fluidity and can form a coating film without defects (such as stripes). Defects will not occur during drying and curing process, and a photopolymer layer showing desired physical properties and surface properties can be formed.

[0188] On the other hand, according to another embodiment of the present invention, there is provided a hologram recording medium including a photopolymer layer formed of the photopolymerizable composition.

[0189] Unless otherwise specifically stated, the term "hologram recording medium" as used herein means a medium on which optical information can be recorded in the entire visible light range and ultraviolet range (e.g., 300 nm to 1200 nm) via an exposure process. For example, the hologram herein may include all visual holograms, such as on-axis (Gabor) holograms, off-axis holograms, full aperture transfer holograms, white light transmission holograms ("rainbow holograms"), Denisyuk holograms, off-axis reflection holograms, edge-illuminated holograms, or holographic stereograms.

[0190] Since the photopolymer layer is formed of the photopolymerizable composition (photopolymer composition), it exhibits a large refractive index modulation value and high diffraction efficiency despite its thin thickness, thereby ensuring excellent optical recording characteristics and achieving excellent reliability even in a high temperature / high humidity environment.

[0191] The thickness of the photopolymer layer may be, for example, in the range of 5.0 μm to 40.0 μm. Specifically, the lower limit of the thickness of the photopolymer layer may be, for example, 6 μm or more, 7 μm or more, 8 μm or more, or 9 μm or more. In addition, the upper limit of the thickness may be, for example, 35 μm or less, 30 μm or less, 29 μm or less, 28 μm or less, 27 μm or less, 26 μm or less, 25 μm or less, 24 μm or less, 23 μm or less, 22 μm or less, 21 μm or less, 20 μm or less, 19 μm or less, or 18 μm or less.

[0192] The hologram recording medium may further include a substrate on at least one surface of the photopolymer layer. The type of substrate is not particularly limited, and those known in the relevant technical field may be used. For example, a substrate such as glass, PET (polyethylene terephthalate), TAC (triacetyl cellulose), PC (polycarbonate) or COP (cycloolefin polymer) may be used.

[0193] The hologram recording medium can have a high diffraction efficiency. In one example, when a notch filter hologram is recorded, the hologram recording medium can have a diffraction efficiency of 70% or more. Wherein, the thickness of the photopolymer layer can be, for example, 5μm to 30μm. Specifically, when a notch filter hologram is recorded, the diffraction efficiency can be 75% or more, 80% or more, 85% or more, 86% or more, 87% or more, or 88% or more. In this way, the hologram recording medium can achieve excellent diffraction efficiency even if it includes a thin thickness of the photopolymer layer. The diffraction efficiency can be measured by the method described in the test example described below.

[0194] Even if the thickness of the photopolymer layer is as thin as 5 μm to 30 μm, the hologram recording medium can achieve a refractive index modulation value (Δn) of 0.020 or more, 0.025 or more, 0.026 or more, 0.027 or more, 0.028 or more, 0.029 or more, 0.030 or more, 0.031 or more, 0.032 or more, 0.033 or more, 0.034 or more, or 0.035 or more. The upper limit of the refractive index modulation value is not particularly limited, but may be, for example, 0.060 or less. The refractive index modulation value can be measured by the method described in the test example described below.

[0195] The hologram recording medium may exhibit excellent durability in a high temperature / high humidity environment. In one example, the peak change rate of the hologram recording medium calculated by the following Equation 3 may be 3% or less.

[0196] [Equation 3]

[0197] Peak change rate = {|1-A1 / A0|}×100

[0198] Wherein, in Equation 3, A0 is the wavelength of the lowest transmittance of the hologram recording medium for the wavelength range of 300 nm to 1,200 nm, and A1 is the wavelength of the lowest transmittance measured after exposing the hologram recording medium to a temperature of 60° C. and a relative humidity of 90% for 72 hours.

[0199] The peak change rate calculated by Equation 3 is 3% or less, which means that even when exposed to severe conditions such as high temperature / high humidity, the deformation (contraction or expansion) of the diffraction grating can be suppressed as if its peak change rate is 3% or less. Such a hologram recording medium can provide good color reproducibility and image clarity even when exposed to severe conditions.

[0200] The peak change rate of the hologram recording medium may be, for example, 2.5% or less, 2.0% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, or 1.1% or less. The lower limit of the peak change rate is not particularly limited and may be 0% or more.

[0201] A hologram recording medium according to another embodiment of the present invention has high durability against heat and moisture, and thus can exhibit high adhesive force even after aging in a high temperature / high humidity environment.

[0202] In one example, the hologram recording medium of another embodiment of the present invention can have an adhesion of 500 gf / 2.5 cm or more, measured at a peeling angle of 180° and a peeling speed of 5 mm / sec after storage for 72 hours at a temperature of 60°C and a relative humidity of 90% in a laminated state in which the photopolymer layer is in contact with the optically transparent adhesive layer.

[0203] The type of optically transparent adhesive layer is not particularly limited, and may be, for example, a rubber-based adhesive layer, an acrylic adhesive layer, or a silicone-based adhesive layer. The hologram recording medium of other embodiments is not limited to those that exhibit excellent adhesion to all types of adhesive layers. However, the hologram recording medium of other embodiments may exhibit excellent adhesion to multiple types of adhesive layers.

[0204] The lower limit of adhesive force can be, for example, 530gf / 2.5cm or more, 550gf / 2.5cm or more, 600gf / 2.5cm or more, 700gf / 2.5cm or more, 800gf / 2.5cm or more, 850gf / 2.5cm or more, 900gf / 2.5cm or more, 950gf / 2.5cm or more, 1000gf / 2.5cm or more, 1020gf / 2.5cm or more, 1050gf / 2.5cm or more, or 1100gf / 2.5cm or more. About the method for measuring adhesive force, refer to the method described in the test example described below. The upper limit of adhesive force is not particularly limited, and can be 2500gf / 2.5cm or less.

[0205] On the other hand, since the hologram recording medium uses a mixture of a component having a low refractive index and a component having a high refractive index to record optical characteristics, it tends to have opaque characteristics due to their compatibility. However, by using a fluorinated compound having a specific structure with which they have excellent compatibility, the hologram recording medium can exhibit highly transparent optical characteristics.

[0206] In one example, the haze of the hologram recording medium can be 2% or less. The upper limit of the haze can be, for example, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, or 0.7% or less. The lower limit of the haze is not particularly limited and can be 0% or more. The haze can be measured by the method described in the test example described below.

[0207] Hologram recording media not only exhibit excellent optical recording characteristics and excellent durability in high temperature / high humidity environments, but also exhibit highly transparent optical characteristics, which is expected to provide various optical elements that can be used even in environments that generate a lot of heat or have high humidity.

[0208] The hologram recording medium is not limited thereto but may be a hologram recording medium on which a reflection hologram or a transmission hologram is recorded.

[0209] In one example, the diffraction grating of the photopolymer layer may be a reflection hologram grating. In the case of a transmission hologram grating, since the diffraction grating is formed in a direction perpendicular to the substrate plane, the linear expansion coefficient of the substrate and the linear expansion coefficient of the photopolymer have a greater influence on the deformation of the grating. In contrast, since the reflection hologram grating is formed in a direction parallel to the substrate plane, the expansion or contraction of the volume holographic grating formed in the photopolymer rather than the linear expansion coefficient mismatch between the substrate and the diffraction grating has a greater influence on the image clarity. Therefore, the hologram recording medium having the above-mentioned peak variation characteristics is more suitable for reflection holograms.

[0210] In one example, the diffraction grating of the photopolymer layer may be parallel to the bottom surface on which the substrate is disposed or formed in the horizontal direction of the bottom surface on which the substrate is disposed. Here, parallel or horizontal means substantially parallel or horizontal, and may mean that the diffraction grating is parallel or horizontal within an error range of ±5°, ±4°, ±3°, ±2°, or ±1° relative to the edge angle of the bottom surface on which the substrate is disposed.

[0211] Regarding the diffraction grating structure, the hologram recording medium may have a notch filter structure. A hologram recording medium of an embodiment having a notch filter structure may mean that the diffraction grating is non-tilted (substantially 0°) relative to the substrate surface, for example, as if the diffraction grating is parallel to the substrate surface. Such a hologram recording medium may have a structure in which two layers (e.g., a high refractive index layer and a low refractive index layer) with different refractive indices are repeated alternately. In addition, the two repeated layers may have predetermined thicknesses that are the same or different from each other, respectively. Such a non-tilted diffraction grating recording may be prepared in a manner that the incident angle of the incident object light and the incident angle of the reference light are equal based on the normal. In the non-tilted structure, the degree of deformation (e.g., contraction or expansion) under high temperature / high humidity conditions is more clearly confirmed compared to the tilted structure, and it is less affected by the contraction and expansion of the substrate.

[0212] The use of the hologram recording medium of one embodiment is not particularly limited. As a non-limiting example, the hologram recording medium can be used in applications that are likely to be exposed to high temperature / high humidity environments, specifically smart devices, such as mobile devices, parts of wearable displays, or automotive parts (such as head-up displays).

[0213] On the other hand, according to another embodiment of the present invention, a method for preparing a hologram recording medium is provided, which includes the following steps: applying a photopolymerizable composition to form a photopolymer layer; and irradiating a coherent laser onto a predetermined area of ​​the photopolymer layer and selectively polymerizing photoreactive monomers contained in the photopolymer layer to record optical information.

[0214] The photopolymerizable composition may be a photopolymer composition of one embodiment of the present invention, and the photopolymer composition has been described above in detail, so a detailed description thereof is omitted here.

[0215] In the step of forming the photopolymer layer, a photopolymer composition including the above structure may be first prepared. When preparing the photopolymer composition, in order to mix the components, a known mixer, a stirrer, a mixer, etc. may be used without particular limitation. In addition, such a mixing process may be performed at a temperature ranging from 0°C to 100°C, a temperature ranging from 10°C to 80°C, or a temperature ranging from 20°C to 60°C.

[0216] In the step of forming the photopolymer layer, the prepared photopolymer composition may be applied to form a coating film formed of the photopolymer composition. The coating film may be dried naturally at room temperature or at a temperature in the range of 30° C. to 80° C. This process may cause a hydrosilylation reaction between the hydroxyl group of the (meth) acrylic polyol remaining unreacted and the silane functional group of the siloxane-based polymer.

[0217] In the photopolymer layer prepared by the step of forming the photopolymer layer, the fluorinated compound, the photoreactive monomer and the photoinitiator system, and additives added as needed may be uniformly dispersed in a cross-linked polymer matrix.

[0218] Subsequently, in the step of recording optical information, if coherent laser light is irradiated onto the photopolymer layer, polymerization of the photoreactive monomer occurs in the region where constructive interference occurs to form a photopolymer, and polymerization of the photoreactive monomer does not occur or is suppressed in the region where destructive interference occurs, so that the photoreactive monomer exists. In addition, when the unreacted photoreactive monomer causes refractive index modulation while diffusing toward the photopolymer side where the concentration of the photoreactive monomer is lower, a diffraction grating is generated by the refractive index modulation. Thus, a hologram (i.e., optical information) is recorded on the photopolymer layer having the diffraction grating.

[0219] The method for preparing a hologram recording medium may further include, after the step of recording the optical information, a step of performing photobleaching by irradiating light onto the entire photopolymer layer on which the optical information is recorded.

[0220] In the photobleaching step, ultraviolet rays are irradiated onto the photopolymer layer on which the optical information is recorded to terminate the reaction of the photoreactive monomers remaining in the photopolymer layer, thereby removing the color of the photosensitizing dye. In one example, in the photobleaching step, ultraviolet rays (UVA) in the range of 320 nm to 400 nm are irradiated to terminate the reaction of the photoreactive monomers and remove the color of the photosensitizing dye.

[0221] On the other hand, according to another embodiment of the present invention, there is provided an optical element including a hologram recording medium.

[0222] Specific examples of optical elements may include smart devices such as mobile devices, components of wearable displays, vehicle products (such as head-up displays), holographic fingerprint recognition systems, optical lenses, reflectors, deflection mirrors, filters, diffuser screens, diffraction elements, light guides, waveguides, holographic optical elements with projection screen and / or mask functions, media for optical storage systems and light diffuser plates, optical wavelength multiplexers, reflective and transmissive color filters, etc.

[0223] An example of an optical element including a hologram recording medium may include a hologram display device. The hologram display device includes a light source unit, an input unit, an optical system, and a display unit.

[0224] Specifically, the light source unit is a portion that irradiates a laser beam for providing, recording, and reproducing three-dimensional image information of an object in the input unit and the display unit.

[0225] The input unit is a part that pre-inputs three-dimensional image information of the object to be recorded on the display unit, specifically, the three-dimensional information of the object such as the intensity and phase of light in each space can be input into the electrically addressed liquid crystal SLM, where the input light beam can be used.

[0226] The optical system may include a reflector, a polarizer, a beam splitter, a beam gate, a lens, etc. The optical system may be allocated into an input beam for sending a laser beam emitted from a light source unit to an input unit, a recording beam for sending a laser beam to a display unit, a reference beam, an erasing beam, a reading beam, etc.

[0227] The display unit can receive the three-dimensional image information of the object from the input unit, record it on the hologram plate including the optically addressed SLM, and reproduce the three-dimensional image of the object. At this time, the three-dimensional image information of the object can be recorded by the interference of the input light beam and the reference light beam. The three-dimensional image information of the object recorded on the hologram plate can be reproduced as a three-dimensional image through the diffraction pattern generated by the read light beam. The erase light beam can be used to quickly remove the formed diffraction pattern. On the other hand, the hologram plate can be moved between the position of the input three-dimensional image and the position of the reproduced three-dimensional image.

[0228] Beneficial Effects

[0229] The fluorinated compound according to one embodiment of the present invention is contained in the photopolymerizable composition, thereby being able to provide a hologram recording medium and an optical element including the same which not only have excellent optical recording characteristics but also exhibit transparent optical characteristics and excellent reliability even in a high temperature and high humidity environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0230] Figure 1 The recording device setup for hologram recording is schematically shown. Specifically, Figure 1 The following process is schematically shown: laser light of a predetermined wavelength is radiated from a light source 10 and is irradiated onto a PP (hologram recording medium) 80 located on one surface of a reflector 70 via reflectors 20 and 20', an aperture 30, a spatial filter 40, an aperture 30', a collimating lens 50 and a PBS (Polarized Beam Splitter) 60. DETAILED DESCRIPTION

[0231] Hereinafter, the action and effect of the present invention will be described in more detail with reference to specific embodiments of the present invention. However, these embodiments are presented for illustrative purposes only, and the scope of the present invention is not limited thereby in any way.

[0232] In the following Preparation Examples, Examples, and Comparative Examples, unless otherwise specified, the content of raw materials and the like means the content based on the solid content.

[0233] Preparation Example 1: Preparation of fluorinated compounds

[0234] 200g malonic acid, 900g 2,2,3,3,4,4,5,5-octafluoro-1-amyl alcohol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 19mL sulfuric acid (H2SO4) is added dropwise.The reactor equipped with Dean-Stark separator is used to remove the water produced, and keeps 24 hours.After reaction is completed, reaction mixture is cooled to room temperature, further adds water and washing, then organic layer is concentrated.800g intermediate product is obtained by high vacuum distillation.

[0235] 800g of the obtained intermediate product, 437g of potassium carbonate, 28g of tetra-n-butylammonium iodide, 525g of 2-bromoethyl methyl ether and 800mL of dimethylformamide were added to a 2L jacket reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 800mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 1600mL of 3% hydrochloric acid, and the organic layer was concentrated. 800g of the fluorinated compound represented by the following chemical formula a was obtained by high vacuum distillation.

[0236] [Chemical formula a]

[0237]

[0238] Preparation Example 2: Preparation of fluorinated compounds

[0239] 200g malonic acid, 820g 2,2,3,3,4,4,5,5,6,6-ten fluoro-1-hexanol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is added dropwise.The water produced is removed using the reactor equipped with Dean-Stark separator, and kept for 24 hours.After the reaction is completed, the reaction mixture is cooled to room temperature, further water is added and washed, and then the organic layer is concentrated.The 600g intermediate product is obtained by high vacuum distillation.

[0240] 600g of the obtained intermediate product, 276g of potassium carbonate, 18g of tetra-n-butylammonium iodide, 330g of 2-bromoethyl methyl ether and 600mL of dimethylformamide were added to a 2L jacket reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 800mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 1600mL of 3% hydrochloric acid, and the organic layer was concentrated. 500g of the fluorinated compound represented by the following chemical formula b was obtained by high vacuum distillation.

[0241] [Chemical formula b]

[0242]

[0243] Preparation Example 3: Preparation of fluorinated compounds

[0244] 200g malonic acid, 820g 2,2,3,3,4,4,5,5,6,6-ten fluoro-1-hexanol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is added dropwise.The water produced is removed using the reactor equipped with Dean-Stark separator, and kept for 24 hours.After the reaction is completed, the reaction mixture is cooled to room temperature, further water is added and washed, and then the organic layer is concentrated.The 600g intermediate product is obtained by high vacuum distillation.

[0245] 600g of the intermediate product obtained, 276g of potassium carbonate, 18g of tetra-n-butylammonium iodide, 435g of 1-bromo-2-(2-methoxyethoxy)ethane and 600mL of dimethylformamide were added to a 2L jacketed reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 800mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 1600mL of 3% hydrochloric acid, and the organic layer was concentrated. 490g of the fluorinated compound represented by the following chemical formula c was obtained by high vacuum distillation.

[0246] [Chemical formula c]

[0247]

[0248] Preparation Example 4: Preparation of fluorinated compounds

[0249] 200g malonic acid, 815g 2,2,3,3,4,4,5,5,6,6-decafluorohex-1-amine and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is added dropwise.The water produced is removed using the reactor equipped with Dean-Stark separator, and kept for 24 hours.After the reaction is completed, the reaction mixture is cooled to room temperature, further water is added and washed, and then the organic layer is concentrated.600g intermediate product is obtained by high vacuum distillation.

[0250] 600g of the intermediate product obtained, 277g of potassium carbonate, 18g of tetra-n-butylammonium iodide, 436g of 1-bromo-2-(2-methoxyethoxy)ethane and 600mL of dimethylformamide are added to a 2L jacketed reactor, and the temperature is maintained at 90°C. After reacting for 24 hours, the reaction mixture is cooled to room temperature, 800mL of chloroform is added, stirred, and then filtered. The filtrate filtered is washed with 1600mL of 3% hydrochloric acid, and the organic layer is concentrated. 500g of the fluorinated compound represented by the following chemical formula d is obtained by high vacuum distillation.

[0251] [Chemical formula d]

[0252]

[0253] Preparation Example 5: Preparation of fluorinated compounds

[0254] 200g malonic acid, 410g 2,2,3,3,4,4,5,5,6,6-ten fluoro-1-hexanol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is dripped.The reactor equipped with Dean-Stark separator is used to remove the water produced, and keeps 24 hours.After reaction is completed, reaction mixture is cooled to room temperature, 2-(2-methoxyethoxy)-1-ethanol is added thereto, then it is reacted under reflux.After reaction is completed, reaction mixture is cooled to room temperature, further water is added and washed, then organic layer is concentrated.450g intermediate product is obtained by high vacuum distillation.

[0255] 450g of the intermediate product obtained, 278g of potassium carbonate, 18g of tetra-n-butylammonium iodide, 438g of 1-bromo-2-(2-methoxyethoxy)ethane and 600mL of dimethylformamide were added to a 2L jacketed reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 800mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 1600mL of 3% hydrochloric acid, and the organic layer was concentrated. 420g of the fluorinated compound represented by the following chemical formula e was obtained by high vacuum distillation.

[0256] [Chemical formula e]

[0257]

[0258] Preparation Example 6: Preparation of fluorinated compounds

[0259] 200g malonic acid, 820g 2,2,3,3,4,4,5,5,6,6-ten fluoro-1-hexanol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is added dropwise.The water produced is removed using the reactor equipped with Dean-Stark separator, and kept for 24 hours.After the reaction is completed, the reaction mixture is cooled to room temperature, further water is added and washed, and then the organic layer is concentrated.The 600g intermediate product is obtained by high vacuum distillation.

[0260] 600g of the obtained intermediate product, 276g of potassium carbonate, 18g of tetra-n-butylammonium iodide, 174g of 1-bromo-2-(2-methoxyethoxy)ethane and 600mL of dimethylformamide were added to a 2L jacket reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 284g of 1-bromo-1,1,2,2,3,3,4,4,4-nonafluorobutane was added, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 800mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 1600mL of 3% hydrochloric acid, and the organic layer was concentrated. 300g of the fluorinated compound represented by the following chemical formula f was obtained by high vacuum distillation.

[0261] [Chemical formula f]

[0262]

[0263] Preparation Example 7: Preparation of fluorinated compounds

[0264] 200g malonic acid, 820g 2,2,3,3,4,4,5,5,6,6-ten fluoro-1-hexanol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is added dropwise.The water produced is removed using the reactor equipped with Dean-Stark separator, and kept for 24 hours.After the reaction is completed, the reaction mixture is cooled to room temperature, further water is added and washed, and then the organic layer is concentrated.The 600g intermediate product is obtained by high vacuum distillation.

[0265] 400g of the obtained intermediate product, 184g of potassium carbonate, 12g of tetra-n-butylammonium iodide, 473g of 1-bromo-1,1,2,2,3,3,4,4,4-nonafluorobutane and 600mL of dimethylformamide were added to a 2L jacket reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 400mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 800mL of 3% hydrochloric acid, and the organic layer was concentrated. 450g of the fluorinated compound represented by the following chemical formula g was obtained by high vacuum distillation.

[0266] [Chemical formula g]

[0267]

[0268] Preparation Example 8: Preparation of fluorinated compounds

[0269] 200g malonic acid, 410g 2,2,3,3,4,4,5,5,6,6-ten fluoro-1-hexanol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is dripped.The water produced is removed using the reactor equipped with Dean-Stark separator, and keeps 24 hours.After reaction is completed, reaction mixture is cooled to room temperature, 2-methoxyethanol is added thereto, and it is reacted under reflux.After reaction is completed, reaction mixture is cooled to room temperature, further water is added and washed, and then organic layer is concentrated.450g intermediate product is obtained by high vacuum distillation.

[0270] 400g of the intermediate product obtained, 273g of potassium carbonate, 18g of tetra-n-butylammonium iodide, 172g of 1-bromo-2-(2-methoxyethoxy)ethane and 600mL of dimethylformamide were added to a 2L jacketed reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, 281g of 1-bromo-1,1,2,2,3,3,4,4,4-nonafluorobutane was added, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, and 800mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 1600mL of 3% hydrochloric acid, and the organic layer was concentrated. 320g of the fluorinated compound represented by the following chemical formula h was obtained by high vacuum distillation.

[0271] [Chemical formula h]

[0272]

[0273] Preparation Example 9: Preparation of fluorinated compounds

[0274] 200g malonic acid, 410g 2,2,3,3,4,4,5,5,6,6-ten fluoro-1-hexanol and 800mL toluene are added in 2L jacket reactor, and it is reacted under reflux.After about 1 hour, 14mL sulfuric acid (H2SO4) is dripped.The reactor equipped with Dean-Stark separator is used to remove the water produced, and keeps 24 hours.After reaction is completed, reaction mixture is cooled to room temperature, and 2-(2-methoxyethoxy)-1-ethanol is added thereto, and it is reacted under reflux.After reaction is completed, reaction mixture is cooled to room temperature, further water is added and washed, and then organic layer is concentrated.450g intermediate product is obtained by high vacuum distillation.

[0275] 400g of the obtained intermediate product, 273g of potassium carbonate, 18g of tetra-n-butylammonium iodide, 700g of 1-bromo-1,1,2,2,3,3,4,4,4-nonafluorobutane and 600mL of dimethylformamide were added to a 2L jacket reactor, and the temperature was maintained at 90°C. After reacting for 24 hours, the reaction mixture was cooled to room temperature, and 400mL of chloroform was added, stirred, and then filtered. The filtered filtrate was washed with 800mL of 3% hydrochloric acid, and the organic layer was concentrated. 520g of the fluorinated compound represented by the following chemical formula i was obtained by high vacuum distillation.

[0276] [Chemical formula i]

[0277]

[0278] Preparation Example 10: Preparation of (meth)acrylic polyol

[0279] 132g butyl acrylate, 420g ethyl acrylate and 48g hydroxybutyl acrylate are added to a 2L jacket reactor and diluted with 1200g ethyl acetate. The reaction temperature is set to 60°C to 70°C, and the mixture is stirred for about 30 minutes to 1 hour. 0.42g n-dodecyl mercaptan (n-DDM) is further added and stirred for about 30 minutes. Then, 0.24g AIBN is added as a polymerization initiator, and polymerization is carried out at the reaction temperature for 4 hours or more, and maintained until the residual acrylate content becomes less than 1%. Thus, a copolymer based on (meth) acrylate in which hydroxyl groups are located in the side chains (weight average molecular weight of about 300,000, OH equivalent of about 1802g / equivalent) is prepared.

[0280] Example 1: Preparation of photopolymer composition and hologram recording medium

[0281] (1) Preparation of photopolymer composition

[0282] First, 1.27 g of poly(methylhydrogensiloxane) (Sigma-Aldrich, number average molecular weight: about 390, Si—H equivalent: about 103 g / equivalent) as a siloxane-based polymer and 11.12 g of the (meth)acrylic polyol prepared in Preparation Example 10 were mixed (SiH / OH molar ratio = 2.0).

[0283] Then, 20 g of HR 6042 (Miwon Specialty Chemical, refractive index 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 co-initiator, 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 shielding from light. Thereafter, a photopolymer composition was prepared by adding a Karstedt (Pt-based) catalyst for matrix crosslinking.

[0284] (2) Preparation of hologram recording media

[0285] The photopolymer composition was coated on a 60 μm thick TAC substrate to a predetermined thickness using a Mayer rod, and dried at 80° C. for 10 minutes. The thickness of the photopolymer layer after drying was about 15 μm.

[0286] Use with Figure 1The diffraction grating is recorded with the same settings as in the embodiment. Specifically, when the prepared photopolymer layer is laminated on a reflector and then irradiated with a laser, a notch filter hologram having a periodic refractive index modulation in the thickness direction by interference between the incident light L and the light L' reflected from the reflector can be recorded. In this embodiment, the notch filter hologram is recorded at an incident angle of 0° (degrees). Notch filters and Bragg reflectors are optical devices that reflect only light of a specific wavelength, and have a structure in which two layers with different refractive indices are periodically and repeatedly stacked at a certain thickness.

[0287] Examples 2 to 9 and Comparative Examples 1 to 3: Preparation of Photopolymer Compositions and Hologram Recording Media

[0288] 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.

[0289] [Table 1]

[0290]

[0291] [Chemical formula j]

[0292]

[0293] [Chemical formula k]

[0294]

[0295] [Chemical formula 1]

[0296]

[0297] Test example: Performance evaluation of hologram recording media

[0298] (1) Diffraction efficiency

[0299] The diffraction efficiency (η) is determined by the following Equation 1.

[0300] [Equation 1]

[0301] η(%)={P D / (P D +P T )}×100

[0302] Where, in equation 1, η is the diffraction efficiency, P D is the output of the diffracted beam of the sample after recording (mW / cm 2 ), and P T is the output of the transmitted light beam of the sample after recording (mW / cm 2 ).

[0303] (2) Refractive index modulation value (Δn)

[0304] The refractive index modulation value (Δn) is determined by the following Equation 2 and the Bragg equation.

[0305] [Equation 2]

[0306]

[0307] [Bragg equation]

[0308]

[0309] Wherein, in the equation, η is the reflection diffraction efficiency (DE), d is the thickness of the photopolymer layer, λ is the wavelength of the incident light for recording (660nm or 532nm), θ is the incident angle of the incident light for recording, φ is the tilt angle of the grating, Δn is the refractive index modulation value, n is the refractive index of the photopolymer, and Λ means the diffraction grating period. In the above embodiments and comparative examples, since the notch filter method is used to record the hologram, both θ (incident angle) and φ (tilt angle of the grating) are 0°.

[0310] (3) Haze

[0311] The haze was measured using a haze meter (Murakami Color Research Laboratory, HM-150) in accordance with JIS K 7136. The measurement light was made incident on the substrate-side surface of the hologram recording medium.

[0312] (4) Peak change rate

[0313] First, the specific wavelength (or wavelength band) (A0) at which the sample with the highest reflectivity (i.e., lowest transmittance) of the diffraction grating is recorded is analyzed (analyzed at room temperature and not under high humidity conditions). The analysis is performed using a UV-Vis spectrometer, and the analysis wavelength range is 300nm to 1,200nm.

[0314] 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) (A1) at which the reflectance was the largest (transmittance was the smallest) was recorded in a similar manner. The peak change rate was measured according to the following equation 3, which is the degree of movement of the wavelength with the lowest transmittance before and after the evaluation. At this time, it is assumed that sample deformation (such as contraction or expansion) does not affect the surface pitch and occurs only in the direction perpendicular to the sample surface.

[0315] [Equation 3]

[0316] Peak change rate = {|1-A1 / A0|}×100

[0317] (5) Adhesion after aging

[0318] As a rubber-based OCA (optically clear adhesive) 61563 (thickness: 50 μm, TESA) was laminated on a glass substrate to form an adhesive layer, and then the adhesive layer was laminated so that the photopolymer layer of the sample on which the diffraction grating was recorded was in contact with the adhesive layer. Then, the obtained sample was cut to have a width of 2.5 cm, and a sample laminated in the order of a glass substrate, an adhesive layer, a photopolymer layer, and a TAC substrate was prepared.

[0319] The prepared sample was stored at a temperature of 60°C and a relative humidity of 90% for 72 hours, and then the adhesion between the photopolymer layer and the adhesive layer was measured using a texture analyzer. The peeling angle when measuring the adhesion was 180° and the peeling speed was 5 mm / sec.

[0320] [Table 2]

[0321]

[0322] Referring to Table 2, it is determined that the hologram recording media prepared in Examples 1 to 9 not only exhibit excellent diffraction efficiency, refractive index modulation value, and low haze, but also exhibit high adhesion even after exposure to a high temperature / high humidity environment, have little change in the wavelength at which the maximum reflectivity occurs, and are excellent in reliability in a high temperature / high humidity environment. In contrast, the hologram recording medium prepared in Comparative Example 2 is poor in optical recording characteristics, haze, and reliability in a high temperature / high humidity environment. In addition, the hologram recording media prepared in Comparative Examples 1 and 3 are excellent in optical recording characteristics, but exhibit poor reliability in a high temperature / high humidity environment.

[0323] Therefore, it was confirmed that when the fluorinated compound according to one embodiment of the present invention is used, a hologram recording medium having excellent optical recording characteristics, having excellent reliability even in a high temperature / high humidity environment, and exhibiting high transparency can be provided.

Claims

1. A fluorinated compound represented by the following chemical formula 1: [Chemical formula 1] in, In Chemical Formula 1, Z 1 and Z 2 are each independently -O-, -S-, or -NH-, R 1 To R 4 At least one of the fluorine-containing substituents is an alkyl group having 1 to 20 carbon atoms substituted by 2 or more fluorine groups, a cycloalkyl group having 3 to 30 carbon atoms substituted by 2 or more fluorine groups, or an aryl group having 6 to 30 carbon atoms substituted by 2 or more fluorine groups, When R 1 To R 4 When not a fluorine-containing substituent, they are each independently 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 -CH2- of the above substituents is replaced by -O-, -S- or -NH-.

2. The fluorinated compound according to claim 1, wherein R in Chemical Formula 1 1 A fluorine-containing substituent.

3. The fluorinated compound according to claim 1, wherein the fluorine-containing substituent is a linear alkyl group having 1 to 20 carbon atoms substituted with 2 or more fluorines, a cycloalkyl group having 3 to 12 carbon atoms substituted with 2 or more fluorines, or an aryl group having 6 to 14 carbon atoms substituted with 2 or more fluorines.

4. The fluorinated compound according to claim 1, wherein the fluorinated substituent is -(CH2) a (CF2) b CHF2, -(CH2) a (CF2) b CF3, or decafluorocyclohexyl, a is an integer from 0 to 3, and b is an integer from 0 to 19.

5. The fluorinated compound according to claim 1, wherein when R in Chemical Formula 1 1 To R 4 When it is not a fluorine-containing substituent, R 1 To R 4 Each is independently 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, a heteroaryl group having 4 to 12 carbon atoms, an arylalkyl group having 7 to 16 carbon atoms, or -(R 5 -Y 1 ) c -R 6 , R 5 is an alkylene group having 1 to 6 carbon atoms, R 6 is an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms, Y 1 is -O- or -S-, and c is an integer from 1 to 12, provided that when c is 2 or greater, R 5 The same as or different from each other.

6. The fluorinated compound according to claim 1, wherein the fluorinated compound represented by 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 to 1-9: [Chemical formula 1-1] in, In Chemical Formula 1-1, Z a1 and Z b1 are each independently -O-, -S-, or -NH-, R a1 and R b1 Each independently is CF3 or CHF2, R c1 and R c2 are each independently an alkylene group having 1 to 6 carbon atoms, Y a1 and Y a2 are each independently -CH2-, -O-, -S-, or -NH-, R d1 and R d2 are each independently an alkylene group having 1 to 4 carbon atoms, R e1 and R e2 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group, p1 and p2 are each independently an integer from 0 to 9, and q1 and q2 are each independently an integer from 0 to 3, [Chemical formula 1-2] Wherein, in Chemical Formula 1-2, Z a2 and Z b2 are each independently -O-, -S-, or -NH-, R a2 is CF3 or CHF2, R c3 To R c5 are each independently an alkylene group having 1 to 6 carbon atoms, Y a3 To Y a5 are each independently -CH2-, -O-, -S-, or -NH-, R d3 To R d5 are each independently an alkylene group having 1 to 4 carbon atoms, R e3 To R e5 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group, p3 is an integer from 0 to 9, and q3 to q5 are each independently an integer from 0 to 3, [Chemical formula 1-3] Wherein, in chemical formula 1-3, Z a3 and Z b3 are each independently -O-, -S-, or -NH-, R a3 , R b2 and R b3 Each independently is CF3 or CHF2, R c6 is an alkylene group having 1 to 6 carbon atoms, Y a6 is -CH2-, -O-, -S-, or -NH-, R d6 is an alkylene group having 1 to 4 carbon atoms, R e6 is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group, R f1 and R f2 are each independently hydrogen or fluorine, p4 to p6 are each independently an integer from 0 to 9, and q6 is an integer from 0 to 3, [Chemical formula 1-4] Wherein, in chemical formula 1-4, Z a4 and Z b4 are each independently -O-, -S-, or -NH-, R a4 , R a5 , R b4 and R b5 Each independently is CF3 or CHF2, R f3 To R f6 are each independently hydrogen or fluorine, and p7 to p10 are each independently an integer from 0 to 9, [Chemical formula 1-5] Wherein, in chemical formula 1-5, Z a5 and Z b5 are each independently -O-, -S-, or -NH-, R a6 and R a7 Each independently is CF3 or CHF2, R c7 and R c8 are each independently an alkylene group having 1 to 6 carbon atoms, Y a7 and Y a8 are each independently -CH2-, -O-, -S-, or -NH-, R d7 and R d8 are each independently an alkylene group having 1 to 4 carbon atoms, R e7 and R e8 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group, p11 to p12 are each independently an integer from 0 to 9, and q7 and q8 are each independently an integer from 0 to 3, [Chemical formula 1-6] Wherein, in chemical formula 1-6, Z a6 and Z b6 are each independently -O-, -S-, or -NH-, R a8 To R a10 Each independently is CF3 or CHF2, R c9 is an alkylene group having 1 to 6 carbon atoms, Y a9 is -CH2-, -O-, -S-, or -NH-, R d9 is an alkylene group having 1 to 4 carbon atoms, R e9 is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cyclohexyl group, or a phenyl group, p13 to p15 are each independently an integer from 0 to 9, and q9 is an integer from 0 to 3, [Chemical formula 1-7] Wherein, in Chemical Formula 1-7, Z a7 and Z b7 are each independently -O-, -S-, or -NH-, and R b9 , R c10 and R d10 are each independently decafluorocyclohexyl, phenyl, pyridyl, pyrimidinyl, or methoxyethyl, [Chemical formula 1-8] Wherein, in Chemical Formula 1-8, Z a8 and Z b8 are each independently -O-, -S-, or -NH-, and R b10 , R c11 and R d11 are each independently 2,2,3,3,4,4,5,5-octafluoro-1-pentyl, decafluorocyclohexyl, phenyl, or methoxyethyl, [Chemical formula 1-9] Wherein, in Chemical Formula 1-9, Z a9 and Z b9 are each independently -O-, -S-, or -NH-, R a11 and R b11 Each independently is CF3 or CHF2, R c12 and R d12 are each independently phenyl or benzyl, and p16 and p17 are each independently an integer of 0 to 9.

7. A photopolymerizable composition comprising: The fluorinated compound according to claim 1; A polymer matrix or a precursor thereof; a photoreactive monomer; and Photoinitiator system.

8. A hologram recording medium comprising a photopolymer layer formed from the photopolymerizable composition according to claim 7.

9. A method for preparing a hologram recording medium, comprising the steps of: applying the photopolymerizable composition according to claim 7 to form a photopolymer layer; and irradiating coherent laser light onto a predetermined area of ​​the photopolymer layer and selectively polymerizing photoreactive monomers contained in the photopolymer layer to record optical information.

10. An optical element comprising the hologram recording medium according to claim 8.

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