Summary of the invention
The objective of the invention is to disclose a kind of reflection holography thin film and preparation method thereof, to overcome the above-mentioned defective that prior art exists;
Another object of the present invention provides a kind of photosensitive polymer film that can recording reflection holography;
A further object of the present invention provides a kind of holographic light-sensitive coating, is used to prepare described photosensitive polymer film material.
The said holographic light-sensitive coating of the present invention comprises photopolymer coating and the solvent that matches, and described photopolymer coating comprises following components in weight percentage:
Film forming agent 20%~80%
Nano combined performed polymer 4%~20%
Monomer 10%~50%
Light trigger 0.5%~7%
Chain-transferring agent 0.3%~5%
Photosensitizer 0.05%~2%
The weight solid content of said holographic light-sensitive coating is 5%-50%;
Preferred percentage by weight is as follows:
Film forming agent 30%~70%
Nano combined performed polymer 8%~20%
Monomer 15.0%~40.0%
Light trigger 2.0%~7.0%
Chain-transferring agent 1.0%~~3.0%
Photosensitizer 0.5%~2.0%
Said film forming agent is to provide baseline refractive index to system, links the important component of nano combined performed polymer and monomer, initiator system and relevant auxiliary agent, and to forming required physical property and the index modulation of reflection hologram important contribution is arranged after exposure.Its refractive index, cohesion, cohesive force, pliability, compatibility etc., as the important indicator of selecting material, said film forming agent is selected from polymethylmethacrylate, poly-cellulose acetate butyl ester, the multipolymer of cellulose acetate butyl ester and ethyl vinyl ether, the blend of polyvinyl butyral and cellulose acetate, polyvinyl acetate (PVA)-butyl acrylate-acrylic ternary copolymer or polystyrene vinyl cyanide etc., or the composite material of above-mentioned polymkeric substance and fluoropolymer, said fluoropolymer is selected from the multipolymer of chlorotrifluoroethylene vinyl acetate base ether or the multipolymer of tetrafluoroethene and ethyl vinyl ether;
Said monomer is selected from two or more in the diacrylate of bisphenol-A of esters of acrylic acid, N-vinylcarbazole class, ethoxylation of simple function group or difunctional or the tristane dimethanol diacrylate, and the part by weight between two kinds of monomers is 1: 0.4~0.9;
Preferably, said monomer is the potpourri of N-vinylcarbazole and tristane dimethanol diacrylate, and weight ratio is 1: 0.5~0.8;
Said nano combined performed polymer is to contain the monomer of alkenyl group and the product that nano particle adopts the in-situ polymerization preparation on a kind of terminal position;
The general structure of monomer that contains alkenyl group on the said terminal position is as follows:
Wherein:
R
1Represent H or CH
3R
2Represent COOCH
3, COOC
4H
9Or
The monomer preferable methyl methyl acrylate, butyl methacrylate or the 4-thiopurine methyltransferase styrene that contain alkenyl group on the said terminal position;
Said nano particle is selected from TiO
2, ZnO or ZnS particle, particle diameter is 20~50 nanometers;
Consider the compatibility of material, preferred nano combined performed polymer be contain the ZnS particle methyl methacrylate the in-situ polymerization product or contain the cinnamic in-situ polymerization product of 4-thiopurine methyltransferase of ZnS particle.
The weight content of nano particle in nano combined performed polymer is 0.2%~2%, preferred 0.6~1.0%;
The weight-average molecular weight of preferred nano combined performed polymer is 5000~50000;
Described nano combined performed polymer, nano particle by the performed polymer parcel, be a kind of nano composite material with high index, can come the refractive index of control material according to the content of nano particle, purpose is to improve the material that participates in polymerization after the sensitization and penetrates the rate modulation value;
The preparation method of said nano combined performed polymer can adopt the method for in-situ polymerization, is summarized as follows:
With the unsaturated class monomer of the thiazolinyl that contains unsaturated group on initiating agent, the terminal position and nano particle in inert atmosphere, 70~75 ℃ of reactions 20~30 minutes, cooling, stored refrigerated is stand-by.
Light trigger, chain-transferring agent and photosensitizer constitute light initiation system, initiator system is the key factor of decision luminous sensitivity, initiator system comprises one or more when with the light radiation excitation, can directly produce the compound of free radical, and its free radical can carry out polymerization by trigger monomer;
Preferred light trigger is selected from 2,4,6-triphenyl imidazole radicals doublet or dibenzoyl;
Preferred photosensitizer is selected from the red B of algae, lignocaine-benzal cyclopentanone, michaelis ketone or 1,3,3-trimethyl-2-[5-(1,3,3-trimethyl-2-indoles fork)-1,3-pentadiene] the indoles salt compounded of iodine etc.;
Preferred chain-transferring agent is selected from 2-mercaptobenzoxazole, lauryl mercaptan or mercaptobenzothiazoler;
Said solvent is the mixed solvent of butanone/methylene chloride, and its part by weight is 4~6: 0.5~1.5: 0.5~1.5, preferably: 5: 1: 1;
Preferably, described photopolymer coating also comprises plastifier and/or 0.1~1% the ultraviolet absorber and/or 0.1~1% the non-ionic surfactant of photopolymer coating general assembly (TW) 0.5~3%;
Plastifier is selected from phthalic ester, alkyl acid ester, polyglycol carboxylate or diethyl sebacate, ultraviolet absorber is selected from 2-hydroxyl-4-methoxy benzophenone or 2-(2H-benzotriazole-2)-4,6-two (1-methyl isophthalic acid-phenethyl) phenol, non-ionic surfactant are selected from the plain surfactant Fluorad of fluorine that polyglycol, methoxy poly (ethylene glycol) or 3M company produce
FC-4430 (CAS No.108-88-3) is in order to regulate paintability.
The said photosensitive polymer film that can recording reflection holography of the present invention, comprise basement membrane and coated cushion, the photopolymer coating that the holographic light-sensitive coating of coated on the cushion opposite side forms and the surface protection film that covers photopolymer dope layer surface on basement membrane one side, the thickness of dried photopolymer dope layer is 3~50 μ m;
Said basement membrane is selected from PVC, PET or the BOPP film of 20~100 μ m, and thickness is 20~100 μ m;
Said cushion is the articulamentum of photopolymer dope layer and basement membrane, material therefor can adopt vinyl acetate close with the basement membrane refractive index and light solidifying coatings such as acrylic acid esters co-polymer, vinylidene chloride styrene vinyl acetate co-polymer or employing esters of acrylic acid, and coating thickness is 1~2 μ m.
Said surface protection film, can adopt the base material of existing release coating, preferred thickness is PET film, BOPP film, PE or the PVC film of 16~23 μ m, and this have PET film, BOPP film, PE or the PVC film of release coating all can purchase on market, as the PET film product of toray company;
The said reflection holography thin film of the present invention records the interference fringe of hologram image or two color-changing image-texts on the photopolymer coating of said photosensitive polymer film that can recording reflection holography;
The preparation method of said reflection holography thin film C comprises the steps:
(1) preparation of coating material: at the lucifuge conditioned disjunction under red light, in proportion film forming agent, nano combined pre-polymerization monomer, monomer, initiating agent and photosensitizer are added in the solvent, stirring and dissolving, obtain said photosensitive coating A, preferably, can add components such as plastifier, ultraviolet absorber and/or surfactant simultaneously;
(2) preparation of photosensitive polymer film material B: on the coating basement membrane, be coated with cushion, at the lucifuge conditioned disjunction under red light, photosensitive coating A with step, be coated on the basement membrane of existing cushion, drying is 1~5 minute under 65-75 ℃, dry back covered with protective film promptly obtains said photosensitive polymer film material B;
(3) preparation of reflection holography thin film C: the product of step (2) is opened diaphragm, adopt the reflection holography recording method, record a hologram on the photosensitive polymer film material B, on the ultra-violet curing machine, film is carried out ultraviolet and visible light burn-out then, 120 ℃ were heated 2~50 minutes, promptly obtain reflection holography thin film C,, have certain pliability for a kind of solid transparent film photosensitive material;
The wavelength of said red light should adopt lucifuge conditioned disjunction red light greater than 600nm, its objective is the exposure of avoiding photosensitive coating A;
The wavelength of LASER Light Source is 514.5nm or 532nm, and light intensity is 60~110mw/cm
2, the time shutter, LASER Light Source can adopt Argon ion laser (wavelength is 514nm) or semiconductor solid state laser (wavelength 532nm) at 0.1-1.0s;
Said laser log method is a kind of prior art, and as Lippmann's writing-method and Danisyuk method etc., relevant technologies personnel can be with reference to enforcement.
Photosensitive polymer film B of the present invention, it is a kind of photosensitive material that utilizes two kinds of different refractivity polymkeric substance, reference light and thing light by coherent light beam enter recording medium from two opposite sides (or homonymy) interference, excite monomer to carry out free radical polymerization, monomer also participates in nano combined performed polymer and carries out copolymerization, form the polymer stripes of high index of refraction, form hologram, obtain the high-diffraction efficiency hologram image.
The present invention utilizes above-mentioned hologram light sensitive material of high polymer, utilization principle of optical interference, the bright dark alternate reflection strip of formation specific wavelength in this hologram light sensitive material of high polymer.Photopolymerization is to produce the free radical trigger monomer by photochemical method, nano combined performed polymer carries out polymerization, light initiation system is in the optical radiation that is subjected to certain energy specific wavelength, absorb photon and transit to excited state, generate free radical, trigger monomer and nano combined performed polymer carry out polymerization, polymerization takes place at the bright fringes place, cause the monomer at dark fringe place to move to the bright fringes of monomer rareness, nano combined performed polymer is also with monomer one polymerization of bright fringes migration adding free radical in the same way simultaneously, form the nanometer polymer that is different from the film forming agent refractive index, obtained showing bright hologram.
By above-mentioned disclosed technical scheme as seen, holographic light-sensitive film B of the present invention, sensitivity preferably, very high reflection efficiency and higher index modulation value are arranged, storage life is long, hologram is subjected to the influence of environment little, is different from the wet treatment method of conventional photosensitive material, and the resulting records image only need pass through photocuring and hot enhancement process, just can reach reflection efficiency greater than 95% reflected image or two variable color image, be suitable for mass production.
Embodiment
Referring to Fig. 1; the said photosensitive polymer film of the present invention; comprise photopolymer coating 3 that basement membrane 1 and coated form at the cushion 2 on basement membrane 1 one sides, the coated holographic light-sensitive coating on cushion 2 opposite sides and the surface protection film 4 that covers photopolymer dope layer surface, but the interference fringe of imprinting hologram image or two color-changing image-texts on the photopolymer dope layer 3.
The present invention is described by the following examples, but these embodiment are exemplary, the present invention does not limit to this.
Embodiment 1
With 0.012g azoisobutyronitrile, 30g methyl methacrylate and 0.2g ZnS (particle diameter is at 20nm), put in the ground there-necked flask that 100mL is equipped with electric mixer, condenser pipe and logical nitrogen tube, open chilled water, logical nitrogen, start stirrer, stirring rate be 800 change/min).Be heated to 75 ℃, take a sample behind the 20min, make the methyl methacrylate performed polymer that contains the ZnS nano particle, then stop heating, be cooled to room temperature.Stand-by towards the nitrogen stored refrigerated.The weight content of nano particle is 0.66%, and recording weight-average molecular weight is 5600.
Embodiment 2
With 0.02g dibenzoyl, 36g4-thiopurine methyltransferase styrene and 0.35g ZnS (particle diameter is at 30nm), put in the ground there-necked flask that 100mL is equipped with electric mixer, condenser pipe and logical nitrogen tube, open chilled water, logical nitrogen, start stirrer mixed evenly (stirring rate be 1200 change/min).Be heated to 75 ℃, take a sample behind the 20min.Make the 4-thiopurine methyltransferase styrene performed polymer that contains the ZnS nano particle, then stop heating, be cooled to room temperature.Stand-by towards the nitrogen stored refrigerated.The weight content of nano particle is 0.96%, tests to such an extent that weight-average molecular weight is 12000.
Embodiment 3
Under the red safety lamp of wavelength greater than 600nm, with 9.2 gram (77wt%) film forming agent polyvinyl acetate (PVA)-butyl acrylate-acrylic ternary copolymers, monomer N-vinyl carbazole 1.0 grams (8.3wt%), monomer tristane dimethanol diacrylate 0.6 gram (5wt%), methyl methacrylate performed polymer 0.53 gram (4.4% embodiment 1) that contains the ZnS nano particle,
light trigger 2,4,6-triphenyl imidazole radicals doublet 0.078 gram (0.65wt%), photosensitizer lignocaine-benzal cyclopentanone 0.067 gram (0.056wt%), chain-transferring agent 2-mercaptobenzothiazole 0.04 gram (0.33wt%), ultraviolet absorber 2-hydroxyl-4-methoxy benzophenone 0.02 gram (0.17wt%), non-ionic surfactant Fluorad
FC-44300.11 restrains (0.92wt%), plastifier diethyl sebacate 0.34 gram (2.8wt%) is added to mixed solution (butanone: methylene chloride: methyl alcohol=5: 1: 1, weight ratio) in, the weight solid content is 8%, stirring at room is to dissolving, and recording viscosity is 11cp (25 ℃), filters, obtain photosensitive coating, stand-by;
The PET film of choosing the 50 μ m high grades of transparency is a basement membrane 1, and the preparation weight concentration is 40% vinylidene chloride styrene vinyl acetate co-polymer solution, coats basement membrane 1 with the anilox roll of 120 lines, with 60 ℃ of oven dry, obtains cushion 2, and the thickness of cushion is 1 μ m;
The gap of adjusting scraper and dispense tip is 200 μ m, above-mentioned photopolymer coating coated scribble cushion 2, thickness is on the PET film of 50 μ m, in 75 ℃ convective drying case, dry overlay film, coating thickness is 10 μ m, the existing release coating thickness of covering is 23 microns a PET film 4, obtains to be used for the photosensitive polymer film of holographic recording;
The preparation of reflection holography thin film:
Adopt the recording method of " at axle " reflection holography; specifically referring to shown in Figure 2; the said photosensitive polymer film that is used for holographic recording is cut into the sheet material of 30*30mm; be pasted on catoptron 43 after throwing off surface protection film (4); the light beam 300 of Argon ion laser laser (514nm) forms parallel beam 301 by beam expanding lens 41 and the aspheric surface collimation convex lens 42 that have pinhole filter, and light intensity is 60mw/cm
2Radiation is in photosensitive polymer film, flat pattern light 301 arrives catoptron 43 from basement membrane 1 incident through cushion 2 and photopolymer coating 3, and the time shutter is at 0.1s, thereby record a hologram in the photosensitive polymer film that is used for holographic recording, on the ultra-violet curing machine film is carried out ultraviolet and visible light burn-out then, 120 ℃ were heated 2 minutes, promptly obtain reflection holography thin film, vision is visible as holographic mirror.This film is a kind of solid transparent membraneous material, has certain pliability.
Embodiment 4
Under the red safety lamp of wavelength greater than 600nm, blend with film forming agent polyvinyl butyral and cellulose acetate, 2.86 gram (26.0wt%), monomer N-vinyl carbazole 2.66 grams (24.2wt%), diacrylate 1.77 grams (16.1wt%) of the bisphenol-A of monomer ethoxylated, 4-thiopurine methyltransferase styrene performed polymer 2.11 gram (19.2wt% embodiment 2) light trigger isobutyl benzoin ether 0.73 gram (6.6wt%) that contains the ZnS nano particle, photosensitizer michaelis ketone 0.19 gram (1.7wt%), chain-transferring agent 2-mercaptobenzothiazole 0.51 gram (4.6wt%), ultraviolet absorber 2-hydroxyl-4-methoxy benzophenone 0.96 gram (0.88wt%), non-ionic surfactant methoxy poly (ethylene glycol) 0.018 gram (0.16wt%), plastifier diethyl sebacate 0.0594 gram (0.54wt%) is added to mixed solution (butanone: methylene chloride: methyl alcohol=5: 1: 1, weight ratio) in, the weight solid content is 46.3%, stirring at room is to dissolving, record viscosity 28.3cp (25 ℃), filter, obtain photosensitive coating, stand-by;
The PET film of choosing the 36 μ m high grades of transparency is a basement membrane 1, the preparation weight concentration is the copolymer solution of 30% vinyl acetate and butyl acrylate, coats basement membrane 1 with the anilox roll of 100 lines, 50~70 ℃ oven for drying, obtain having the basement membrane of cushion 2, the thickness of cushion is 2 μ m.
The gap of adjusting scraper and dispense tip is 180 μ m, above-mentioned photosensitive coating coated scribble cushion 2, thickness is on the PET film of 30 μ m, in 75 ℃ convective drying case, dry overlay film, coating thickness is 8 μ m, cladding thickness is 16 microns a aluminum plated PET film, obtains to be used for the photosensitive polymer film of holographic recording;
Adopt the method for reflection holography record; see Fig. 2; the above-mentioned photosensitive polymer film that is used for holographic recording is cut into the sheet material of 30*30mm; after throwing off surface protection film 4; be pasted on catoptron 43; with semiconductor solid state laser 532nm recording light source 300, be 100mw/cm by beam expanding lens 41 and aspheric surface collimation convex lens 42 formation parallel beams 301 its light intensity that have pinhole filter
2Radiation is in the photosensitive polymer film that is used for holographic recording, and flat pattern light 301 arrives catoptron 43 or aluminum plated PET film from basement membrane 1 incident through cushion 2 and photographic layer 3, former road reflected back photographic layer, two-beam is interfered, and records a hologram in the photosensitive polymer film that is used for holographic recording, on the ultra-violet curing machine film is carried out ultraviolet and visible light burn-out then, 120 ℃ were heated 2 minutes, promptly obtain reflection holography thin film, the area of reflective membrane is 50 * 50mm, and its light intensity is 100mw/cm
2, this light reflecting membrane is viewed as green an angle, after changing viewing angle, and just visible blue.
Embodiment 5
The evaluation of reflection holography thin film can be passed through coherent light " at axle " recording technique with reference to the method for Fig. 2, carries out the holographic imaging record on photosensitive polymer film.
With the above-mentioned photosensitive polymer film that is used for holographic recording, cut into the sheet material of 30*30mm, throw off surface protection film 4 after, the smooth catoptron 43 that is pasted on.With wavelength 532nm laser instrument is light source, light beam 300 forms parallel beam 301 radiation in photosensitive polymer film by beam expanding lens 41 and the aspheric surface collimation convex lens 42 that have pinhole filter, flat pattern light 301 is from basement membrane 1 incident, arrive catoptron 43 through cushion 2 and photopolymer coating 3, former road reflected back photopolymer coating 3 forms the record grating.The radiation diameter is 15mm.Be recorded in reflection grating respectively with the different recording time under the isocandela.Material behind the record solidifies through the high-pressure mercury mercury lamp, and with the test of S-53 ultraviolet-visible spectrophotometer, establishing the transmitance that does not have the reflection grating place is I
0, test the minimum transmitance I of reflection grating under each different exposure time, and the wavelength X of this position, obtain behind the holographic recording wavelength X=525nm, by formula η=1-I/I
0, calculate maximum reflection efficiency eta=85%, index modulation=0.031.Material after the test is put into 115 ℃ convective drying baking oven, heats 5 minutes, tests with above-mentioned same method once more, and by the data contrast, the sensitivity that obtains material is 21.2mj/cm
2, wavelength X=525nm, maximum reflection efficiency eta=99.9%, by formula M=(λ tanh-1 √ η)/π d, calculate index modulation=0.0763.Testing result shows material when writing down grating without thermal treatment, and reflection efficiency has reached 78%, and after heat treatment, reflection efficiency raises and causes 99.9%, and this dry process can meet the requirement of material fully.Material after treatment carries out soda acid respectively and adds wet process, and image does not disappear.