WO2019066313A1 - Photopolymer composition - Google Patents

Abstract

The purpose of the present invention is to provide: a photopolymer composition capable of more readily providing a photopolymer layer having improved durability against temperature and humidity while having a large refractive index modulation value; a holographic recording medium using the same; an optical device; and a holographic recording method.

Description

 Title of the Invention

 Photopolymer composition

 TECHNICAL FIELD

Cross-reference with related application (s)

 This application claims the benefit of priority based on Korean Patent Application No. 10-2017-0125446, dated September 27, 2017, and Korean Patent Application No. 10-2018-0107996, dated September 10, 2018, The entire contents of which are incorporated herein by reference.

 The present invention relates to a photopolymer composition, a hologram recording medium, an optical element and a holographic recording method.

 TECHNICAL BACKGROUND OF THE INVENTION

 The hologram recording medium records information by changing the refractive index in the holographic recording layer in the medium through an exposure process, and reads the change of refraction in the thus recorded medium to reproduce the information.

 When a photopolymer is used, the light interference pattern can be easily stored in the hologram by photopolymerization of the low molecular weight monomers. Therefore, it is possible to use an optical lens, a mirror, a deflection mirror, a filter, a diffusing screen, A holographic optical element having a function of a waveguide, a projection screen and / or a mask, a medium of an optical memory system and a light diffusing plate, an optical wavelength splitter, a reflection type, and a transmission type color filter.

 Typically, the photopolymer composition for hologram production comprises a polymeric binder, a monomer, and a photoinitiator, and irradiates laser light to a photosensitive film produced from such a composition to induce photopolymerization of a local monomer. In such a photopolymerization process, the refractive index is high at a portion where a relatively large number of monomers exist, and at a portion where a polymer binder is relatively present, a refractive index is relatively low, thereby causing a refractive index modulation. Such a refractive index modulation generates a diffraction grating . The refractive index modulation value n is affected by the thickness of the photopolymer layer and the diffraction efficiency DE, and the angle selectivity becomes wider as the thickness becomes thinner.

In recent years, a high diffraction efficiency and a stable hologram With the demand for the development of materials, various attempts have been made to manufacture a photopolymer layer having a small thickness and a large refractive index modulation value.

 DISCLOSURE OF THE INVENTION

 [Problem to be solved]

 The present invention is to provide a photopolymer composition which can more easily provide a photopolymer layer having a high refractive index modulation value and improved durability against temperature and humidity.

 It is still another object of the present invention to provide a hologram recording medium including a photopolymer layer having a high refractive index modulation value and improved internal structure against temperature and humidity.

 Further, the present invention is to provide an optical element including a hologram recording medium.

 The present invention also provides a holographic recording method comprising selectively polymerizing a photo-polymeric monomer contained in the photopolymer composition by a coherent laser.

 MEANS FOR SOLVING THE PROBLEMS

 (Meth) acrylate-based (co) polymer wherein the silane-based functional group is located in the branch chain and the equivalence of the silane-based functional group is 300 g / eq to 2000 g / eq, and (ii) A polymer matrix comprising a repellent agent or a precursor thereof; Optically active monomer; And a photoinitiator.

 Also, in this specification, a holographic recording medium manufactured from the photopolymer composition is provided.

 Also, in this specification, an optical element including the hologram recording medium is provided.

 Also disclosed herein is a holographic recording method comprising selectively polymerizing a photo-polymeric monomer contained in the photopolymer composition by a coherent laser.

The details of the photopolymer composition, the hologram recording medium, the optical element, and the holographic recording method according to the specific embodiment of the present invention will be described in detail I will explain. In the present specification, (meth) acrylate means methacrylate or acrylate.

 As used herein, the (co) polymer refers to a homopolymer or copolymer (including random copolymers, block copolymers, and graft copolymers).

 In this specification, hologram means a recording medium in which optical information is recorded in the entire visible range and near-ultraviolet range (300-800 nm) through an exposure process, and for example, in- ("Gabor") hologram, of-axi s hologram, full-lap prior hologram, white light transmission hologram ("rainbow hologram"), denisyuk hologram, biaxial hologram , And a visual hologram such as an edge-lterature hologram or a holographic stereogram.

In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 40. According to one embodiment, the alkyl group has 1 to 20 carbon atoms. According to another embodiment, the alkyl group has 1 to 10 carbon atoms. According to another embodiment, the alkyl group has 1 to 6 carbon atoms. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a tert-butyl group, N-propyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, N-heptyl, n-heptyl, 1-methylnyl, cyclopentylmethyl, cyclohectylmethyl, octyl, n-octyl, , 2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylnucyl, 5-methylnucyl and the like. In the present specification, the alkylene group is a divalent functional group derived from an alkene, for example, a straight chain, branched or cyclic group such as a methylene group, an ethylene group, a propylene group, an isobutylene group, a sec -Butylene group, tert-butylene group, pentylene group, nuclear siliconylene group and the like. (Meth) acrylate-based (co) polymer wherein the silane-based functional group is located in the branch chain and the equivalent of the silane-based functional group is 300 g / eq to 2000 g / eq, and (ii) a polymeric matrix or precursor thereof comprising a repellent of a linear silane crosslinker; Optically active monomer; And a photoinitiator, may be provided.

 The present inventors have found that a photopolymer containing a polymer matrix using the (meth) acrylate-based (co) polymer wherein the silane-based functional group is located in the branch chain and the equivalence of the silane-based functional group is 300 g / eq to 2000 g / The inventors have confirmed through experimentation that the hologram formed from the composition can realize the modulation value and the durability against the excellent temperature and humidity even when the thickness of the thinner layer is much higher than that of the hologram previously known.

 More specifically, the (meth) acrylate-based (co) polymer has a silane-based functional group located on the branch chain, and the equivalent of the silane-based functional group is regulated to 300 g / eq to 2000 g / The cross-linking density with the cross-linking agent can be optimized to ensure excellent durability against temperature and humidity compared with the conventional matrix. In addition, by optimizing the cross-linking density described above, a photo- By increasing the mobility between the components, the recording characteristics can be improved by maximizing the refractive index modulation.

 Particularly, a cross-linking structure mediated by a siloxane bond is easily formed between a modified (meth) acrylate-based (co) polymer containing a silane functional group and a linear silane cross-linking agent containing a silane- , And this siloxane bond can provide excellent durability against temperature and humidity.

 The fluorine-based compound or the phosphate-based compound may have a lower refractive index than that of the optically active monomer, so that the polymer matrix or the fluorine-based compound or the phosphate- The refractive index of the photopolymer composition can be minimized and the refractive index modulation of the photopolymer composition can be maximized.

Furthermore, the phosphate-based compound acts as a plasticizer, The glass transition temperature of the polymer matrix is lowered to increase the mobility of the photo-polymerizable monomer and the low refractive index, thereby contributing to the improvement of moldability of the photopolymer composition. Hereinafter, the respective components of the photopolymer composition of one embodiment will be described in more detail.

(1) Polymer matrix or its precursor

 The polymer matrix may serve as a support for the final product such as the photopolymer composition and the film produced therefrom. In the hologram formed from the photopolymer composition, the refractive index may be improved by modifying the refractive index.

 (I) a (meth) acrylate-based (co) polymer in which the silane-based functional group is located in the branch chain and the equivalent of the silane-based functional group is 300 g / eq to 2000 g / ii) a linear silane crosslinking agent. Accordingly, the precursor of the polymer matrix includes a monomer or an oligomer that forms the polymer matrix. Specifically, the silane-based functional group is located in the branch chain, and the equivalent of the silane-based functional group is 300 g / eq to 2000 g / (meth) acrylate-based (co) polymer, or a monomers or an oligomer of the monomers, and a linear silane crosslinking agent, or monomers thereof, or oligomers of the monomers.

 In the (meth) acrylate-based (co) polymer, the silane-based functional group may be located in the branch chain. The silane-based functional group may include a silane functional group or an alkoxysilane functional group, and preferably a trimoxylsilane group may be used as an alkoxysilane functional group.

 The silane-based functional group may form a siloxane bond through a sol-gel reaction with the silane-based container contained in the linear silane crosslinking agent to crosslink the (meth) acrylate-based (co) polymer and the linear silane crosslinking agent.

The (meth) acrylate-based (co) polymer may have a silane-based functional group equivalent of 300 g / eq to 2000 g / eq, or 500 g / eq to 2000 g / From 550 g / eq to 1800 g / eq, or from 580 g / eq to 1600 g / eq, or from 586 g / eq to 1562 g / eq. The silane-based functional group equivalent is an equivalent (g / eq) to one silane-based functional group and is a value obtained by dividing the weight average molecular weight of the (meth) acrylate-based (co) polymer by the number of silane-based functional groups per molecule . The smaller the silane-based functional equivalent value, the higher the functional group density, and the larger the equivalent value, the smaller the functional group density.

Accordingly, the (meth) acrylate-based (co) polymer of a linear and a silane cross-linking density is optimized between a relationship, it is possible to ^"ensure excellent durability compared to conventional matrix for temperature and humidity. In addition, through the above-mentioned cross-link density optimization, the recording property can be improved by maximizing the modulation of refraction by increasing the mobility between the photoreactive monomer having a high refraction and the component having a low refraction index.

 If the equivalence of the silane-based functional group contained in the (meth) acrylate-based (co) polymer is excessively reduced to less than 300 g / eq, the crosslinking density of the matrix becomes too high to inhibit the flowability of the components, May occur. Further, if the equivalent of the silane-based functional group contained in the (meth) acrylate-based (co) polymer is excessively increased to more than 2000 g / eq, the crosslinking density becomes too low to serve as a support, The refractive index modulation value may decrease over time as the interface of the diffraction gratings collapses.

 More specifically, the (meth) acrylate-based (co) polymer may include a (meth) acrylate repeating unit and a (meth) acrylate repeating unit in which the silane-based functional group is located in the branch chain.

 Examples of the (meth) acrylate repeating unit in which the silane functional group is located in the branch chain include repeating units represented by the following formula (1).

[Chemical Formula 1] O

 /

Si - OR ₃

 / \

RtO OR _{2 In the} above formula (1), R 1 to R ₃ are each independently an alkyl group having 1 to 10 carbon atoms, ¾ is hydrogen or an alkyl group having 1 to 10 carbon atoms, and R ₅ is an alkylene group having 1 to 10 carbon atoms.

Preferably, in the above formula (1), R ₃ to R ₃ are each independently a methyl group having 1 carbon atom, R ₄ is a methyl group having 1 carbon atom and R ₅ is a 3-methacryloxypropyl tr imethoxysilane (KBM-503 ) Or a repeating unit derived from R 3 to R 4 is independently a methyl group having 1 carbon atom, R 4 is hydrogen and ¾ is a propylene group having 3 carbon atoms, or a repeating unit derived from 3-Acryloxypropyl tr imethoxysilane (KBM-5103).

 Examples of the (meth) acrylate repeating unit include repeating units represented by the following formula (2).

 2]

In Formula 2, ¾ is an alkyl group having 1 to 20 carbon atoms, and R ₇ is hydrogen or an alkyl group having 1 to 10 carbon atoms. Preferably, R ₆ is a butyl group having 4 carbon atoms, and R ₇ is hydrogen Based repeating unit derived from butyl acrylate.

The molar ratio of the repeating unit of Formula 2 to the repeating unit of Formula 1 may be 0.5: 1 to 14: 1. When the molar ratio of repeating units of the above formula (1) The cross-linking density of the matrix becomes excessively low and can not serve as a support, resulting in a decrease in recording characteristics after recording,

If the molar ratio of the repeating units of 1 is excessively increased, the crosslinking density of the matrix becomes too high and the fluidity of the respective components may be lowered, resulting in a decrease in the refractive index modulation value.

The weight average molecular weight (GPC measurement) of the (meth) acrylate-based (co) polymer may be 100000 g / mol to 5000000 g / mol or 300000 g / mol to 900000 g / ii). In the present specification, the weight average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by the GPC method. In the process of measuring the weight average molecular weight in terms of polystyrene measured by the GPC method, a detector such as a known analyzer and a refractive index detector, and an analyzing column can be used. Temperature conditions, solvents, flow rates can be applied. As a specific example of the above measurement conditions, an evaluation temperature is 160 ^° C using a Waters PL-GPC220 instrument using a Polymer Laboratories PLgel MIX-B 300 sleep length column, 1,2,4-trichlorobenzene is dissolved in a solvent , The flow rate was adjusted at a flow rate of 1 mL / min, the sample was adjusted to a concentration of 10 mg / 10 mL, and then supplied in an amount of 200, and the value of Mw was determined using a calibration curve formed using polystyrene standards. The molecular weight of the polystyrene standards was 2,000 I 10,000 I 30,000 / 70,000 / 200,000 I 700,000 / 2,000,000 / 4,000,000 / 10, 000, 000.

 On the other hand, the linear silane crosslinking agent may be a compound having an average of at least one silane-based container per molecule or a mixture thereof, and may be a compound containing at least one silane-based functional group. The silane-based functional group may include a silane functional group or an alkoxysilane functional group, and preferably a trioxysilane group may be used as an alkoxysilane functional group. The silane-based functional group forms a siloxane bond with a silane-based functional group contained in the (meth) acrylate-based (co) polymer to form a siloxane bond with the sol-gel to form a linear silane crosslinking agent Can be crosslinked.

At this time, the linear silane crosslinking agent has a silane-based functional group equivalent of 200 g / eq to 750 g / eq, or 447 g / eq to 747 g / eq, or from 300 g / eq to 900 g / eq, or from 400 g / / eq. Accordingly, the cross-linking density between the (meth) acrylate-based (co) polymer and the linear silane cross-linking agent is optimized, thereby ensuring excellent durability against temperature and humidity compared to the existing matrix. In addition, through the above-mentioned optimization of the cross-linking density, the mobility between the optically protonic monomer having a high refractive index and the component having a low refractive index is increased, thereby maximizing the refractive index modulation and improving the recording characteristics.

 If the equivalent amount of the silane-based functional group contained in the linear silane crosslinking agent is excessively increased to 1000 g / eq or more, the diffraction grating interface after recording may be broken due to the reduction of the crosslinking density of the matrix, and the loose crosslink density and the low glass Transition silver may cause monomer and plasticizer components to leach to the surface and cause haze. If the equivalence of the silane-based functional groups contained in the linear silane crosslinking agent is excessively reduced to less than 200 g / eq, the crosslinking density becomes too high, which hinders the flowability of the monomer and the plasticizer components, May occur.

 On the other hand, the equivalent ratio of the silane-based functional group located in the branch chain of the (meth) acrylate-based (co) polymer: the ratio of the equivalent amount of the silane-based functional group contained in the linear silane crosslinking agent is from 22: 1 to 0.5: 1 or 0.5: 1, alternatively 15: 1 to 0.5: 1, alternatively 10: 1 to 0.5: 1, alternatively 5: 1 to 0.6: 1, alternatively 4: 1 to 0.7: Lt; / RTI > Accordingly, the cross-linking density between the (meth) acrylate-based (co) polymer and the linear silane cross-linking agent is optimized, thereby ensuring excellent durability against temperature and humidity compared to the conventional matrix. In addition, through the above-mentioned crosslinking density optimization, the recording property can be improved by maximizing the refractive index modulation by increasing the mobility between the photoreactive monomer having a high refractive index and the component having a low refractive index.

More specifically, the linear silane crosslinking agent is a linear polyether having a weight average molecular weight of 100 g / mol to 2000 g / mol, or 300 g / mol to 1000 g / mol, or 300 g / mol to 700 g / mol And may include a main chain and a silane-based functional group bound to the main chain by terminal or branch chains. The linear polyether main chain having a weight average molecular weight of 100 g / mol to 2000 g / nl may include a repeating unit represented by the following formula (3).

 (3)

- (R ₈₀ ) _n- ¾- wherein R 3 is an alkylene group having 1 to 10 carbon atoms and n is an integer of 1 or more, or 1 to 50, or 5 to 20, or 8 to 10 in the general formula (3).

 By introducing the linear silane crosslinking agent into the main chain of the flexible polyether polyol, the fluidity of the components can be improved by controlling the glass transition temperature and the crosslinking density of the matrix.

 On the other hand, the bond between the silane functional group and the polyether backbone may be mediated by a urethane bond. Specifically, the silane-based functional group and the polyether main chain may form a mutual bond through a urethane bond. More specifically, the silicon atom contained in the silane-based functional group may be bonded directly to the nitrogen atom of the urethane bond, , And the R8 functional group contained in the polyether backbone may be directly bonded to the oxygen atom of the urethane bond. The reason why the silane-based functional group and the polyether main chain are bonded through the urethane bond is that the linear silane crosslinking agent is a mixture of the isocyanate compound containing a silane functional group and the isocyanate compound having a weight average molecular weight of 100 g / mol to 2000 g / Type polyether polyol compound, which is produced through the reaction between the polyether polyol compound.

 More specifically, the isocyanate compound is an aliphatic, cycloaliphatic, aromatic or aromatic aliphatic mono-isocyanate di-isocyanate, tri-isocyanate or poly-isocyanate; Or di- isocyanates having urea, urea, urea, carbodiimide, acyl urea, isocyanurate, allophanate, biuret, oxadiazinetrione, uretdione or iminooxyadinedione structures, or di An isocyanate or a polyisocyanate of a polyisocyanate.

 Specific examples of the isocyanate compound containing the silane functional group include 3-isocyanatopropyltriethoxysilane.

The polyether polyol includes, for example, styrene oxide, ethylene Obtained by the condensation of multiple adducts of ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, epichlorohydrin with their adduct addition products and graft products, and polyhydric alcohols or their condensates, Ether polyols and polyhydric alcohols, amines and amino alcohols.

 Specific examples of the polyether poly include OH functionalities of 1.5 to 6 and number-average molecular weights of 200 g / mole to 18000 g / mole, OH functionalities of preferably 4.0 to 1.8 and 600 g / mole to 8000 g Poly (propylene oxide) in the random or block copolymer form, poly (propylene oxide) in the form of random or block copolymers having a number average molecular weight of from 0.5 to 10, preferably from 1.9 to 3.1, and a number average molecular weight from 650 g / mole to 4500 g / (Ethylene oxide) and combinations thereof, or poly (tetrahydrofuran) and mixtures thereof.

As described above, when the silane-based functional group and the polyether backbone each have a urethane bond, a linear silane crosslinking agent can be more easily synthesized. The linear silane crosslinking agent has a weight average molecular weight (GPC measurement) of 500 g / mol to 5000000 g / mol, or 600 g / mol to 10000 g / mol, or 700 g / / mol to 2000 g / mol, or from 900 g / mol to 1500 g / eta &ohgr;. In the present specification, the weight average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by the GPC method. In the process of measuring the weight average molecular weight in terms of polystyrene measured by the GPC method, a detector such as a known analytical device and a Refractive Index Detector and an analytical column may be used. And the solvent flow rate can be applied. For example, Polymer Laboratories PLgel MIX-B 300, manufactured by Waters PL-GPC220 instrument, using an osmolality column, the evaluation temperature is 160 ^° C, 1,2,4-trichlorobenzene is dissolved in a solvent , The flow rate was adjusted at a flow rate of lmL / min, the sample was adjusted to a concentration of 10 mg / 10 mL, and then supplied in an amount of 200 iiL, and the value of Mw was determined using a calibration curve formed using polystyrene standards. The molecular weight of the polystyrene standards is 2,000 I 10,000 I 30,000 I 70,000 I 200,000 I 700,000 / 2,000,000 / 4,000,000 / 10, 000, 000 Respectively.

 (Meth) acrylate-based (co) polymer (i) wherein the silane-based functional group is located in the branch chain and the equivalence of the silane-based container is 300 g / eq to 2000 g / Silane crosslinking agent, 10 to 90 parts by weight, or 20 to 70 parts by weight, or 22 to 70 parts by weight of the linear silane crosslinking agent, based on 100 parts by weight of the (meth) acrylate based (co) polymer, Weight to 65 parts by weight.

 If the content of the linear silane crosslinker is excessively decreased with respect to 100 parts by weight of the (meth) acrylate-based (co) polymer in the antistatic product, the curing rate of the matrix is remarkably slowed to lose its function as a support, (100) parts by weight of the (meth) acrylate-based (co) polymer is excessively increased, the curing rate of the matrix is increased or the curing speed of the Excessive increase of male silane content causes compatibility problems with other components and causes haze.

In addition, the modulus (storage elastic modulus) of the repellent product may be 0.01 MPa to 5 MPa. As a specific example of the above modulus measurement method, a storage modulus (G ') value can be measured at a frequency of 1 Hz ^at room temperature (20 ^° C to 25 ^° C) using a TA Instruments di scrospective hybridometer (DHR) have.

Further, the glass transition temperature of the reaction product may be -40 ^° C to 10 ^° C. Examples of the glass transition temperature measuring method specific, EMA (dynami c mechani cal analysi s) using the equipment jeukjeong strain 0. 1%, frequency 1Hz, a setting condition of a temperature rising rate ^{5 ° C / min -80 ° C} ~ 30 ^And the phase angle (loss modulus) of the film coated with the photopolymerizable composition in the " C " region is measured.

(2) The photoreactive monomer

On the other hand, the photo-polymeric monomer may include a polyfunctional (meth) acrylate monomer or a monofunctional (meth) acrylate monomer. As described above, in the photopolymerization of the photopolymer composition, the monomers are polymerized to increase the refractive index at the portion where the polymer is relatively present, and at the portion where the polymer binder is relatively present, the refractive index is relatively low, And the diffraction grating is generated by such refractive index modulation.

 (Meth) acrylate, (meth) acrylonitrile, or (meth) acrylate, for example, a (meth) acrylate, ) Acrylic acid, or a compound containing a vinyl group or a thiol group.

 Examples of the optically active monomer include polyfunctional (meth) acrylate monomers having a refractive index of 1.5 or more, 1.53 or more, or 1.5 to 1.7, and the refractive index is 1.5 or more, or 1.53 or more, or 1.5 to 1.7. The functional (meth) acrylate monomers may include halogen atoms (bromine, iodine, etc.), sulfur (S), phosphorus (P), or aromatic rings.

 More specific examples of the polyfunctional (meth) acrylate monomers having a refractive index of 1.5 or more include bi sphenol A modi fi ed diery late series, f luorene acrylate series (HR 6022, etc.), bi sphenol fuorene epoxy acrylate series (HR6100, HR6060, HR6042, etc. - Miwon), Halogenated epoxy acrylate series (HR1139, HR3362, etc. - Miwon).

 Another example of the optically active monomer is a monofunctional (meth) acrylate monomer. The monofunctional (meth) acrylate monomer may include an ether bond and a fluorene functional group in the molecule. Specific examples of the monofunctional (meth) acrylate monomer include phenoxybenzyl (meth) acrylate, 0-phenyl (Meth) acrylate, benzyl (meth) acrylate, 2- (phenylcyano) ethyl (meth) acrylate, or biphenylmethyl (meth) acrylate.

The optically active monomer may have a weight average molecular weight of 50 g / mol to 1000 g / mol, or 200 g / mol to 600 g / irol. The weight average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by the GPC method. (3) Photo initiators

 On the other hand, the photopolymer composition of this embodiment includes a photoinitiator. The photoinitiator is a compound that is activated by light or actinic radiation and initiates polymerization of a compound containing a photoactive functional group, such as a photo-reactive monomer. As the photoinitiator, conventionally known photoinitiators can be used without any limitation, and specific examples thereof include photo radical polymerization initiators, photoinitiator polymerization initiators, and photoanion polymerization initiators.

Specific examples of the photoradical polymerization initiator include imidazole derivatives, bisimidazole derivatives, N-arylglycine derivatives, organic azide compounds, titanocene, aluminate complexes, organic peroxides, N-alkoxypyridinium salts, Derivatives, and amine derivatives. More specifically, examples of the photocatalytic polymerization initiator include 1,3-di (t-butyldioxycarbonyl) benzophenone, 3,3 ', 4,4'-tetrakis (t-butyldi oxycarbonyl) benzophenone, 2-mercapto benzimidazole, bis (2,4,5-trphenyl) imidazole, 2,2-dimethoxy-1,2-dihey lethane-1-one (product name: Irgacure 651 I, 1-hydr oxy-cyc 1 ohexy 1 -pheny 1 -ke t one (product name: Irgacure 184 I manufactured by BASF), 2-benzy 1 -2-di met hy 1 amino-1- bis (2,6-difluoro-3- (1H-pyrrolo 1 -yl) -benzonitrile (product name: Irgacure 369 I, 1-y 1) -pheny 1) titanim (trade name: Irgacure 784 manufactured by BASF) and Ebecryl P-115 (manufactured by SK entis). Examples of the cationic ion polymerization initiator include diazonium salt, sulfofiium salt, and iodonium salt, and examples thereof include sulfonic acid ester, imidosulfonate, dialkyl-4 (6-benzene) (ιχ5-cyclopentadienyl) iron (II), and the like can be given as examples of the arylsulfonic acid salt. Further, benzoin tosylate, 2,5-dinitrobenzyltosylate, N-tosylphthalic acid imide and the like are also exemplified. More specific examples of the cationic polymerization initiator include Cyracure UVI-6970, Cyracure UVI-6974 and Cyracure UVI-6990 (manufactured by Dow Chemical Co. in USA), Irgacure 264 and Irgacure 250 -1682 (Manufacturer: Nippon Soda) and the like.

 Examples of the photoanion polymerization initiator include a borate salt, such as butyrylchlorine butyl triphenyl borate (BUTYRYL CHOLINE BUTYL TRIPHENYLBORATE). More specific examples of the polymerization initiator in the above-mentioned sound signal include commercially available products such as Borate V (manufacturer: Spectra group).

 The photopolymer composition of this embodiment may also employ one molecule (Type I) or this molecule (Type II) initiator. (Type I) systems for the free radical photopolymerization can be carried out, for example, by reacting aromatic ketone compounds in combination with tertiary amines, such as benzophenone, alkylbenzophenone, 4,4'-bis (dimethylamino) benzophenone Michler's) ketone), anthrone and halogenated benzophenone or a mixture of this type. The bis (type II) initiators include benzoin and derivatives thereof, benzylketal, acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bisacylphosphine oxide, phenyl Alpha-aminoalkylacetophenone, 1- [4- (phenylthio) phenyl] octane-1,2-dione 2- (0-benzoyloxime) And alpha-hydroxyalkylphenones.

(4) Photopolymer composition

 Wherein the photopolymer composition comprises 20 to 40% by weight of the polymer matrix or precursor thereof and 10 to 70% by weight of the photoactive monomer; And 0.1% by weight to 15% by weight of a photoinitiator. When the photopolymer composition further contains an organic solvent as described later, the content of the above-mentioned components is not more than the sum of these components (excluding the organic solvent) The sum of the components).

 The photopolymer composition may further include a fluorine-based compound. Since the fluorine-based compound has little stability and is low in refractive index, the refractive index of the polymer matrix can be lowered when added to the photopolymer composition, thereby maximizing the refractive index modulation with the monomer.

The fluorine-based compound includes at least one functional group selected from the group consisting of an ether group, an ester group and an amide group, and at least two difluoromethylene groups can do. More specifically, the fluorine-based compound may have a structure represented by the following formula (4) in which a functional group including an ether group is bonded to both terminals of a central functional group including a direct bond or an ether bond in two difluoromethylene periods.

[Chemical Formula 4]

In the formula (4), R _u and R ₁₂ are each independently a difluoromethylene group, 3 and R ₆ are each independently a methylene group, R ₁₄ and R ₁₅ are each independently a difluoromethylene group, R ₁₇ and R ₁₈ are each independently a polyalkylene oxide group, and m is an integer of 1 or more, or 1 to 10, or an integer of 1 to 3. Preferably in Formula 4, Rn and R ₁₂ are each independently difluoro methylene group, R ₁₃ and R ₁₆ are each independently a methylene group, R ₁₄ and R ₁₅ is a group methylene-difluoro each independently , R ₁₇ and R ₁₈ each independently represent a 2-methoxyethoxy methoxy group, and m is an integer of 2.

 The fluorine-based compound may have a refractive index of less than 1.45, or more than 1.3 and less than 1.45. As described above, since the optically maleic monomer has a refractive index of 1.5 or more, the fluorine-based compound can lower the refractive index of the polymer matrix through the refractive index lower than that of the photo-polymeric monomer, have.

 Specifically, the content of the fluorine-based compound may be 30 parts by weight to 150 parts by weight, or 50 parts by weight to 110 parts by weight, and the refractive index of the polymer matrix may be 1.46 to 1.53 with respect to 100 parts by weight of the photoactive monomer. When the amount of the fluorine-based compound is greatly decreased with respect to 100 parts by weight of the photo-polymerizable monomer, the refractive index after recording decreases due to the lack of low refractive index, and the content of the fluorine- There may arise haze due to compatibility with other components or a problem that some fluorine-based compounds are eluted to the surface of the coating layer.

The blended compound has a weight average molecular weight (GPC measurement) of 300 g / mol or more, Or from 300 g / mol to 1000 g / nl. A specific method of measuring the weight average molecular weight is as described above.

 On the other hand, the photopolymer composition may further include a photo-sensitizing dye. The photoengraving dye acts as a sensitizing dye for increasing or decreasing the photoinitiator. More specifically, the photoengraving dye is stimulated by the light irradiated to the photopolymer composition to function as an initiator for initiating polymerization of the monomer and the crosslinking monomer. You can do it together. The photopolymer composition may contain 0.01 wt.% To 30 wt.%, Or 0.05 wt.% To 20 wt.

 The examples of the photo-initiator dye are not limited to a wide variety, and various known compounds can be used. Specific examples of the light-sensitive dye include sulfonium derivatives of ceramidonine, new methylene blue, thioerythrosine triethylammonium, 6-acetylamino-2-methylserine But are not limited to, 6-acetylamino_2-methylceramidonin, eosin, erythrosine, rose bengal, thionine, baseic yellow, pinacanol chloride, Rhodamine 6G, gallocyanine, ethyl violet, Victoria blue R, Celestine blue, QuinaldineRed, crystal violet, violet, Brilliant Green, Astrazon orange G, darrow red, pyronin Y, basic red 29, Kpyrylium iodide, , Saprinin O CSafranin 0), cyanine, methylene blue, Azure A, or a combination of two or more thereof.

 The photopolymer composition may further include an organic solvent. Examples of the organic solvent include, but are not limited to, ketones, alcohols, acetates and ethers, and mixtures of two or more thereof.

Specific examples of such an organic solvent include ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetyl acetone or isobutyl ketone; Alcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol or t-butanol; Ethylacetate, i-propyl acetate, or polyethylene glycol monomethyl ether Acetates and the like; Ethers such as tetrahydrofuran or propylene glycol monomethyl ether; Or a mixture of two or more of these.

 The organic solvent may be added to the photopolymer composition at the time when the components contained in the photopolymer composition are mixed, or may be added to the photopolymer composition while the components are added or dispersed in an organic solvent. If the content of the organic solvent in the photopolymer composition is too small, the flowability of the photopolymer composition may be deteriorated, resulting in defects such as streaks in the finally produced film. In addition, when the organic solvent is added in an excess amount, the solid content is lowered and the coating and film formation are not sufficiently performed, so that the physical properties and surface characteristics of the film may be deteriorated, and defects may occur during the drying and curing process. Accordingly, the photopolymer composition may include an organic solvent such that the concentration of the total solids of the components contained therein is 1 wt% to 70 wt%, or 2 wt% to 50 wt%. The photopolymer composition may further include other additives, a catalyst, and the like. For example, the photopolymer composition may comprise a catalyst commonly known to promote polymerization of the polymer matrix or the photo-labile monomer. Examples of the catalyst include tin octanoate, zinc octanoate, dibutyltin dilaurate, dimethylbis [(1-oxoneodecyl) oxy] stannane, dimethyltin dicarboxylate, zirconium bis Zirconium acetylacetonate, p-toluenesulphonic acid or a tertiary amine such as 1,4-diazabicyclo [2.2.2] octane, diazabicyclo-nonane, di 1-methyl-2H-pyrimido (1, 2-a) pyrimidine, etc. . Examples of the other additives include a defoaming agent or a phosphate-based plasticizer. As the defoaming agent, a silicone-based anti-maleic additive may be used. Examples thereof include Tego Rad 2500. An example of the plasticizer is a phosphate compound such as tributyl phosphate. The plasticizer may be added at a weight ratio of 1: 5 to 5: 1 together with the above-described blend-based compound. The plasticizer may have a refractive index of less than 1.5 and a molecular weight of 700 or less.

The photopolymer composition can be used for hologram recording applications. Meanwhile, according to another embodiment of the present invention, a hologram recording medium manufactured from a photopolymer composition can be provided.

 As described above, by using the photopolymer composition of this embodiment, it is possible to provide a hologram capable of achieving a significantly improved refractive index modulation value and a high diffraction efficiency compared to holograms previously known while having a thinner thickness.

 The hologram recording medium can realize a refractive index modulation value of 0.015 or more, or 0.020 or more, or 0.015 to 0.050, or 0.015 to 0.040, or 0.020 to 0.030, even in the thickness of / m to 30 am.

 The hologram recording medium may have a diffraction efficiency change value of 18% or less, or 17% or less, or 16% or less, or 0.01% to 18%, or 0.01% or less, % To 17%, or 0.01% to 16%.

 [Formula 4]

Diffraction efficiency change value (Δ) = [Diffraction efficiency (-) of sample stored in a dark room under constant temperature and humidity conditions of 20 to 25 ^° C and 40 to 50% before recording - Constant temperature humidity of 40 ^° C and 90 RH% (R * 100) of samples stored in a dark room under constant temperature and humidity conditions of 20 to 25 ^° C and 40 to 50 H¾ before recording.

 Further, the hologram recording medium may have a diffraction efficiency of 50% or more, or 85% or more at a thickness of 5 to 30 mm.

The photopolymer composition of this embodiment is prepared by uniformly mixing each component contained therein and drying and curing at a temperature of 20 ^° C or higher, followed by a predetermined exposure process to expose the entire visible and near ultraviolet regions 300 to 800 lt; RTI ID = 0.0 > nm) < / RTI >

 In the photopolymer composition of the embodiment, the polymer matrix or its precursor-forming component may first be homogeneously mixed, and the linear silane crosslinking agent may be added to the catalyst together with the catalyst to prepare a process for forming a hologram.

The photopolymer composition of this embodiment may comprise one or more of the components The stirring may be carried out using a conventional stirrer, a stirrer, a mixer or the like without limitation, and the temperature in the stirring process is 0 ^° C to 100 ° C, preferably 10 ^° C to 80 ^° C, It may be 20 ^° C to 60 ^° C.

On the other hand, after the polymer matrix or the precursor-forming components thereof in the photopolymer composition of this embodiment are homogenized and homogeneously mixed, the photopolymer composition at the time when the linear silane crosslinking agent is added is cured at a temperature of 20 ^° C or higher ≪ / RTI >

The temperature of the curing may vary depending on the composition of the photopolymer and is promoted, for example, by heating to a temperature of 30 ^° C to 180 ^° C.

 During the curing, the photopolymer may be injected into a predetermined substrate or mold or coated.

 Meanwhile, a method of recording a visual hologram on a hologram recording medium manufactured from the photopolymer composition can be carried out without any limitations, and a method described in the holographic recording method of the embodiment to be described later is referred to as one It can be adopted as an example. On the other hand, according to another embodiment of the invention, a holographic recording method can be provided, which comprises selectively enhancing a photo-polymeric monomer contained in the photopolymer composition by a coherent laser.

As described above, it is possible to produce a medium in which the visual hologram is not recorded through the process of shaking and curing the photopolymer composition, and the visual hologram can be recorded on the medium through a predetermined exposure process. ^'

The visual hologram can be recorded on a medium provided through the process of shaking and curing the photopolymer composition using a known apparatus and method under a conventionally known condition. On the other hand, according to another embodiment of the invention, an optical element including a hologram recording medium can be provided. Specific examples of the optical element include a holographic optical element having a function of an optical lens, a mirror, a deflecting mirror, a filter, a diffusion screen, a diffraction member, a light guide, a waveguide, a projection screen and / A light diffusion plate, a light wavelength splitter, a reflection type, and a transmission type color filter.

 An example of an optical element including the hologram recording medium is a hologram display device.

 The hologram display device includes a light source unit, an input unit, an optical system, and a display unit. The light source unit irradiates a laser beam used for providing, recording, and reproducing three-dimensional image information of an object in an input unit and a display unit. In addition, the input unit is a part for inputting three-dimensional image information of an object to be recorded in the display unit in advance. For example, in an electrical ly addressed lid crystal SLM (SLM) Three-dimensional information of the same object can be input, and the input beam can be used at this time. The optical system may include a mirror, a polarizer, a universal splitter, a beam shutter, and a lens. The optical system includes an input unit for transmitting a laser beam emitted from a light source unit to an input unit, a recording beam transmitted to a display unit, Reading beams and so on.

 The image display unit receives the three-dimensional image information of the object from the input unit, records the three-dimensional image information on the hologram plate composed of the optically driven SLM opU cal ly addressed SLM, and reproduces the three-dimensional image of the object. At this time, the three-dimensional image information of the object can be recorded through the interference of the input beam and the reference beam. The three-dimensional image information of the object recorded on the holographic plate is converted into a three- , And the canceller can be used to quickly remove the formed diffraction grating. On the other hand, the hologram plate can be moved between a position at which the 3D image is input and a position at which the 3D image is reproduced.

 【Effects of the Invention】

 According to the present invention, there is provided a photopolymer composition capable of more easily providing a photopolymer layer having a high refractive index modulation value and improved durability against temperature and humidity, a hologram recording medium using the same, an optical element, and a holographic recording method .

DETAILED DESCRIPTION OF THE INVENTION The invention will be described in more detail in the following examples. It should be noted, however, that the following examples are illustrative of the present invention and are not intended to limit the scope of the present invention. [Preparation Example 1: Preparation of silane polymer]

154 g of butyl acrylate and 46 g of KBM-503 (3-methacryloxypropyltrimethylcisilane) were added to a 2 L jacket and diluted with 800 g of ethyl acetate. The reaction temperature was set at 60-70 ^° C and stirring was continued for 30 minutes to 1 hour. 0.02 g of n-dodecylmercaptan was further added, and stirring was further continued for about 30 minutes. Thereafter, 0.06 g of AIBN, which is a polymerization initiator, was added, and the polymerization was carried out for 4 hours or more at the reaction temperature, and the polymerization was continued until the residual acrylate content became less than that of the silane polymer (weight average molecular weight Mw = 500,000 to 600,000 g / mol , _Si (0R) ₃ equivalent = 1019 g / eq). [Preparation Example 2: Preparation of silane polymer]

180 g of butyl acrylate and 120 g of KBM-503 (3-methacryloxypropyltrimeroxysilane) were added to a 2 L jacket and the mixture was pale-kneaded with 700 g of ethyl acetate. The reaction temperature was set at 60-70 ^° C and stirring was continued for 30 minutes to 1 hour. 0.03 g of n-dodecyl mercaptan was further added, and stirring was further continued for about 30 minutes. Thereafter, 0.09 g of AIBN, which is a polymerization initiator, was added and the polymerization was continued for 4 hours or more in the degree of polymerization. The polymerization was continued until the residual acrylate content became less than 1% to obtain a silane polymer (weight average molecular weight: (G / mol), -Si (0R) ₃ equivalent = 586 g / eq). [Preparation Example 3: Preparation of silane polymer]

255 g of butyl acrylate and 45 g of KBM-503 (3-methacryloxypropyltrimeroxysilane) were added to a 2 L jacket and the mixture was pale-kneaded with 700 g of ethyl acetate. The reaction temperature was set at 60-70 ^° C and stirring was continued for 30 minutes to 1 hour. 0.03 g of n-dodecyl mercaptan was further added, and stirring was further continued for about 30 minutes. Thereafter, 0.09 g of AIBN as a polymerization initiator was added, and polymerization was carried out at a reaction temperature for 4 hours or more (Weight average molecular weight Mw = 500,000 to 600,000 g / mol, _Si (0R) ₃ equivalent = 1562 g / eq) was maintained until the residual acrylate content became less than that of the silane polymer. [Preparation Example 4: Preparation of linear silane crosslinking agent]

In a 1000 ml flask, 19.79 g of KBE-9007 (3-isocyanatopropyltriethoxysilane), 12.80 g of PEG-400 and 0.57 g of DBTDL were added and the mixture was paleogeographed with 300 g of tetrahydrofuran. The mixture was stirred at room temperature until it was confirmed that all of the water was consumed by TLC, and then the reaction solution was decompressed to remove all the unreacted solvent. 28 g of a liquid product with a purity of 95% or more was obtained in a yield of 91% by column chromatography under a developing solution of dichloromethane: methyl alcohol = methyl alcohol = 30: 1. (Weight average molecular weight Mw = 900 g / mol, -Si (OR) ₃ equivalent = 447 g / eq)

[Preparation Example 5: Preparation method of linear silane crosslinking agent]

 In a 1000 ml flask, KBE-9007 (3-isocyanatopropyltriethoxysilane)

20 g of PEG-1000 and 0.38 g of DBTDL were added, and the mixture was diluted with 200 g of tetrahydrofuran. After stirring at room temperature until all of the reactants were confirmed to be consumed by TLC, the reaction mixture was reduced in pressure to remove all of the unreacted solvent. 26 g of a liquid product with a purity of 90% or more was obtained through column chromatography under a developing solution of dichloromethane: methyl alcohol = 30: 1 in a yield of 84%. (Weight average molecular weight Mw = 1500 g / mol, -Si (0R) ₃ equivalent = 747 g / eq)

[Preparation Example 6: Preparation of bipartite low refractive material]

Add 20.51 g of 2,2 '- ((oxybis (1,1,2,2-tetrafluoroethane-2,1-diyl) bis (oxy)) bis (2,2-difluoroethan-1-ol) After dissolving in 500 g of tetrahydrofuran, 4.40 g of sodium hydride (60% dispersion in mineral oil) was carefully added several times while stirring at 0 ^° C. After stirring at 0 ^° C for 20 minutes, 12.50 ml of 2-methoxyethoxymethyl chloride was slowly dropped. When it was confirmed that all of the water was consumed by ¾ NMR, all of the unreactive solvents were removed by decompression. Three times with 300 g of dichloromethane The organic layer was collected, filtered with magnesium sulphate, and then decompressed to remove all dichloromethane to obtain 29 g of a liquid product having a purity of 95% or more at a yield of 98%. [Comparative Preparation Example 1: Production of silane polymer]

180 g of butyl acrylate and 20 g of KBM-503 (3-methacryloxypropyltrimethoxysilane) were added to a 2 L jacket reactor and diluted with 800 g of ethyl acetate. The reaction temperature was set at 60-70 ^° C and stirring was continued for 30 minutes to 1 hour. 0.02 g of n-dodecyl mercaptan was further added, and stirring was further continued for about 30 minutes. Thereafter, 0.06 g of AIBN, which is a polymerization initiator, was added and the polymerization was carried out at the reaction temperature for 4 hours or longer to maintain the residual acrylate content until the residual acrylate content became less than 1% to obtain a silane polymer (weight average molecular weight = 500,000 to 600,000, Si - (0R) ₃ equivalent = 2343 g / eq).

[Comparative Preparation Example 2: Method for producing silane polymer]

20 g of butyl acrylate and 180 g of KBM-503 (3-methacryloxypropyltrimeroxysilane) were added to a 2 L jacket, and diluted with 800 g of ethyl acetate. The reaction temperature was set at 60-70 ^° C and stirring was continued for 30 minutes to 1 hour. 0.02 g of n-dodecyl mercaptan was further added, and stirring was further continued for about 30 minutes. Thereafter, 0.06 g of AIBN, which is a polymerization initiator, was added and the polymerization was carried out at the reaction temperature for 4 hours or longer to maintain the residual acrylate content until the residual acrylate content became less than 1% to obtain a silane polymer (weight average molecular weight = Si- (OH) ₃ equivalent = 260 g / eq).

[Examples and Comparative Examples: Production of photopolymer composition]

(High refractive index acrylate, refractive index: 1.600, HR6022 [trade name], manufactured by Production Examples 1 to 3 or Comparative Production Examples 1 to 2), Production Example 6 (Dibutylglycine), Ebecryl P-115 (SK is isocyanate), tributyl phosphate (TBI), molecular weight 266.31, refractive index 1.424, manufactured by Sigma Aldrich) ), Borate V (Spectra group), Irgacure 250 (BASF), silicone-based antirust additives (Tego Rad 2500) and methyl isobutyl ketone (MIBK) were mixed in a state of blocking light, and stirred with a Paste mixer for about 3 to 10 minutes to obtain a transparent coating liquid.

The linear silane crosslinking agent obtained in Production Examples 4 to 5 was added to the above coating solution and further stirred for 5 to 10 minutes. Then, 0.02 g of DBTDL as a catalyst was added to the coating solution, stirred for about 1 minute, coated on a TAC substrate with a thickness of 6 / dish using a meyer bar, and dried at 40 ^° C for 1 hour. The sample was allowed to stand for 24 hours or more in a dark room under constant temperature and humidity conditions of relative humidity of about 25 ^° C and 50 RH%. [Experimental Example: Holographic Recording]

 (1) The photopolymer coated surface prepared in each of the above-described embodiment and comparative example was laminated to a glass, and the laser was fixed so as to pass through the glass surface in advance during recording.

 (2) Diffraction efficiency () measurement

 A holographic recording was made through the interference of two interfering beams (reference beam and object beam), and the transmissive recording caused the two beams to be incident on the same side of the sample. The diffraction efficiency varies with the incidence angle of the two beams, and becomes non-uniform if the incidence angles of the two beams are the same. The diffraction grating is generated perpendicular to the film, since the incidence angle of the two beams is equal to the normal line.

 Recording in transmission type non-linear method using laser of 532nm wavelength

(2 Θ = 45 ^° ;), and the diffraction efficiency (r) was calculated by the following general formula (1).

[Formula 1]

In the formula 1, II is the diffraction efficiency, PD is the output quantity (mW / cuf) of the diffracted beam in the sample after the recording, Ρ _Τ is the output quantity (mW / cuO of the transmitted beam of the recorded sample.

(3) Measurement of refractive index modulation value The lossless dielectric grating of the transmission type hologram can calculate the refractive index modulation value (DELTA eta) from the following general formula (2).

[Formula 2]

In the general formula (2), d is the thickness of the photopolymer layer, DELTA eta is the refractive index modulation value, n (DE) is the diffraction efficiency, and?

(4) Measurement of laser loss (I _loss )

The laser loss amount (1 ₁₀ ) can be calculated from the following general formula (3).

 [Formula 3]

 Iioss = [1 - KPD + Pτ) I Io>] * 100

Wherein in formula 3, P _D is output amount (mW / cin ²⁾ of the diffracted beam in the sample after the recording, Ρ _τ is the output quantity of the transmitted beam (mW / oif) of the recorded sample, ₁₀ is a recording light intensity to be.

(5) Measurement of moisture heat resistance

The photopolymer coated side prepared in each of the above-mentioned Examples and Comparative Examples was allowed to stand in a dark room under constant temperature and humidity conditions of 40 ^° C and 90 RH% for 24 hours or more and then diffraction efficiency ( ') Were measured. (The sample was stored in a state in which the protective film was removed). Then, the moisture resistance characteristic (A) was determined through the diffraction efficiency change value according to the following general formula (4).

 [Formula 4]

Diffraction efficiency change value (Δ) = [Diffraction efficiency of the sample stored in the dark room under constant temperature and humidity conditions of 20 to 25 ^° C, 40 to 50% before recording - 40 ° C before recording] (Ri ') of the sample stored in the dark room for more than 24 hours] I Shape efficiency (H) of the sample stored in the dark room at 20 to 25 ^° C and 40 to 50 H% [Table 1]

Experimental Example Measurement Results of Photopolymer Composition of Example and Holographic Recording Medium Prepared Therefrom

 [Table 2]

 Experimental Example Measurement Results of Photopolymer Composition of Comparative Example and Holographic Recording Medium Prepared Therefrom

 As shown in Tables 1 and 2, the photopolymer composition of the Example using the polymer matrix prepared in Preparative Examples 1 to 3 and the polymer matrix having the increased degree of crosslinking using the linear silane crosslinking agent prepared in Preparative Examples 4 to 5, It is possible to provide a hologram in which the loss loss is equal to that of the comparative example and the refractive index modulation value Δη of 0.020 to 0.030, which is larger than that of the comparative example, and the diffraction efficiency change rate is as low as 15% .

In particular, the polymers prepared in Preparations 1 to 3 were prepared in the same manner as in Examples 1 to 5 using the polymers prepared in Preparation Examples 1 to 3, as the equivalents of silane functional groups satisfied the range of 300 g / eq to 2000 g / Holographic recording media using a photopolymer composition were prepared by using Comparative Examples 1 and 2, in which the silane functional equivalent was outside the range of 300 g / eq to 2000 g / eq, It is confirmed that the optical modulator has a remarkably improved refractive index modulation value and anti-wet heat characteristics as compared with Examples 1 and 2.

Claims

Claims:

 [Claim 1]

 (i) a (meth) acrylate-based (co) polymer wherein the silane-based functional group is located in the branch chain and the equivalent of the silane-based functional group is 300 g / eq to 2000 g / A polymer matrix or a precursor thereof;

 Optically active monomer; And

 A photopolymer composition comprising a photoinitiator.

[Claim 2]

 The method according to claim 1,

 Wherein the linear silane crosslinking agent content is 10 parts by weight to 90 parts by weight based on 100 parts by weight of the (meth) acrylate based (co) polymer,

[Claim 3]

 The method according to claim 1,

 Wherein the modulus (storage modulus, G ') of the repellent product is from 0.01 MPa to 5 MPa as measured by a TA Instrument at a frequency of 1 Hz at room temperature.

Claim 4

 The method according to claim 1,

 Wherein the linear silane crosslinking agent comprises a linear polyether backbone having a weight average molecular weight of 100 to 2000 and a silane-based container bound to the main chain by a terminal or branch chain.

[Claim 5]

 5. The method of claim 4,

The bond between the silane-based functional group and the polyether backbone is preferably a urethane bond- . ≪ / RTI >

[Claim 6]

 The method according to claim 1,

 And the equivalent of the silane-based functional group contained in the linear silane crosslinking agent is 200 g / eq to 1000 g / eq.

7.

 In the above,

 Wherein the equivalent ratio of the silane-based container located on the branch chain of the (meth) acrylate-based (co) polymer: the ratio of the equivalents of the silane-based functional groups contained in the linear silane crosslinking agent is from 22: 1 to 0.5: .

[8]

 In Item 1,

 Wherein the photo-polymeric monomer comprises a polyfunctional (meth) acrylate monomer or a monofunctional (meth) acrylate monomer.

[Claim 9]

 In Item 1,

 Wherein the refractive index of the photo-polymerizable monomer is 1.5 or more.

[Claim 10]

 In addition,

 20 to 80% by weight of the polymer matrix or precursor thereof; 10 to 70% by weight of the photoreactive monomer; And

 0.1 to 15% by weight of a photoinitiator.

[Claim 11]

In the first aspect, Wherein the photopolymer composition further comprises a fluorine-based compound.

[12]

 12. The method of claim 11,

 Wherein the fluorine-based compound comprises at least one functional group selected from the group consisting of an ether group, an ester group and an amide group, and at least two difluoromethylene groups.

Claim 13

 12. The method of claim 11,

 Wherein the fluorine-based compound has a refractive index of less than 1.45.

14.

 12. The method of claim 11,

 Wherein the content of the fluorine-based compound is 30 parts by weight to 150 parts by weight based on 100 parts by weight of the photo-amplifying monomer.

[15]

 In Item 1,

 Wherein the polymer matrix has a refractive index of 1.46 to 1.53.

16. The method of claim 16,

 In Item 1,

 Wherein the photopolymer composition further comprises a photoprotective dye, or other additives.

17.

A hologram recording medium produced from the photopolymer composition of claim 1. Claim 18

 An optical element including the hologram recording medium of claim 17. [191]

 Selectively polymerizing the photochromic monomer contained in the photopolymer composition of claim 1 by a coherent laser.