JP2007102202A - Method for manufacturing cholesteric liquid crystal medium having volume-phase hologram - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing a cholesteric liquid crystal medium, having a volume-phase hologram without requiring complicated processes, such as alignment. <P>SOLUTION: After a volume-phase hologram layer 2 is formed on a substrate 1, a cholesteric liquid crystal layer 3 is formed on the volume-phase hologram layer 2. The substrate 1 is detached from the volume-phase hologram layer 2, and an adhesive layer 4 is formed on the substrate-detached surface of the volume-phase hologram layer 2, and a substrate 5 is provided on the adhesive layer 4. Finally, the obtained laminate is die-cut to give a cholesteric liquid crystal medium, having a volume-phase hologram in the form of a label. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for processing a medium for authenticity determination that can be distinguished from one obtained by forgery or falsification based on unauthorized intentions into a label form or transfer foil form suitable for application to an article. About.

  For example, credit cards, savings and savings cards, prepaid cards, commuter passes, passbooks, passports, identification cards, etc. may be counterfeited or tampered with and may cause various problems if used illegally. In order to prevent damage due to tampering, it is desirable to have a function that can identify the authenticity of itself. In addition, music software, video software, game software, computer software, printer consumables, and the like recorded on the medium are also subject to counterfeiting, and similarly, it is desirable to have a function for identifying authenticity. . Conventionally, holograms are frequently used for the purpose of enabling authenticity identification of various articles including these articles.

  In Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-230571), an adhesive layer, a light reflection layer, a printing primer layer, and a printing layer are sequentially laminated on one surface of a heat-shrinkable base film, and an adhesive is adhered to the other surface. There is described a hologram label comprising a laminate in which an agent layer and a release sheet are sequentially laminated.

Further, Patent Document 2 (Japanese Patent Laid-Open No. 11-151877) discloses an object identification medium for optically recognizing an object and identifying the authenticity of the object, which includes a reflective layer. An object identification medium comprising a hologram provided with a polymer cholesteric liquid crystal is disclosed.
JP 2004-230571 A Japanese Patent Laid-Open No. 11-151877

  A hologram as disclosed in Patent Document 1 can be reproduced by simple reproduction illumination light or white light, and it is not always difficult to forge it by a technique such as replication. Once the forgery is possible, the hologram is precise and it is difficult to distinguish between a genuine hologram and a forged hologram. For this reason, security such as labels and seals made of such holograms is not always perfect.

  For such simple holograms, the applicant has applied a label that combines the hologram function and the discriminating function based on the circular polarization property exhibited by the cholesteric liquid crystal layer (cholesteric with volume hologram). Liquid crystal media).

  Note that in this specification, the term “liquid crystal layer” is used to mean a layer having optically liquid crystal properties, and the state of the layer has a liquid crystal phase in addition to a fluid liquid crystal phase. It also includes the state of a solid phase that is solidified while maintaining the molecular arrangement.

  An outline of a label combining such a hologram function and a discriminating function based on circular polarization exhibited by the cholesteric liquid crystal layer will be described. Such a label mainly has a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer. The volume hologram layer is formed after, for example, applying a volume hologram recording material on an appropriate support film. Interference fringes corresponding to the wavefront of light from an object are recorded in the layer in the form of transmittance modulation and refractive index modulation, and can be easily copied and exposed by developing with the volume hologram master in close contact. Can be made. Examples of the recording material include known volume hologram recording materials such as silver salt materials, dichromated gelatin emulsions, photopolymerizable resins, and photocrosslinkable resins, and in particular, photosensitive materials for dry volume phase hologram recording applications. And those comprising a matrix polymer, a photopolymerizable compound, a photopolymerization initiator, and a sensitizing dye. The cholesteric liquid crystal layer has a spiral structure in which the direction of the director (molecular long axis) of the liquid crystal molecules is continuously rotated in the thickness direction of the liquid crystal layer as the physical molecular arrangement of the liquid crystal molecules. Based on the physical molecular arrangement of such liquid crystal molecules, it has a polarization separation characteristic that separates a circularly polarized light component in one direction and a circularly polarized light component in the opposite direction. That is, natural light incident on such a cholesteric liquid crystal layer is separated into two circularly polarized components, right-handed and left-handed, one being transmitted and the other being reflected. This phenomenon is known as circular dichroism, and when a spiral direction in the spiral structure of liquid crystal molecules is appropriately selected, a circularly polarized component having the same optical rotation direction as this spiral direction is selectively reflected. As a material of the cholesteric liquid crystal layer, for example, a three-dimensionally crosslinkable polymerizable monomer molecule or polymerizable oligomer molecule can be used. When a polymerizable monomer molecule or polymerizable oligomer molecule is formed into a liquid crystal layer at a predetermined temperature, this becomes a nematic state, but if an arbitrary chiral agent is added here, a chiral nematic liquid crystal (cholesteric liquid crystal) is obtained. . Then, in this state, the polymerization is started by a photoinitiator added in advance and ultraviolet rays irradiated from the outside, or the polymerization is directly started by an electron beam, whereby the liquid crystal phase state cholesteric liquid crystal layer ' These liquid crystal molecules are three-dimensionally cross-linked (polymerized) and cured, and solidified as a solid phase cholesteric liquid crystal layer.

  The label having the two-layer structure of the volume hologram layer and the cholesteric liquid crystal layer configured as described above is the same as a conventional hologram in that the color changes or looks three-dimensional as usual. Authentication can be judged. Further, since the cholesteric liquid crystal layer as described above is also superimposed on the volume hologram layer, for example, a pair of glasses including a polarizing plate that transmits right circularly polarized light and a polarizing plate that transmits left circularly polarized light is prepared. When the label is viewed through, the reflected light from the label can be confirmed with one polarizing plate, and the reflected light from the label cannot be confirmed with the other polarizing plate, so that a further authenticity determination can be made.

  Patent Document 2 describes a hologram that is an identification medium for identifying the authenticity of an object and is provided with a polymer cholesteric liquid crystal in a reflective layer. Is a relay type and has a structure in which a cholesteric liquid crystal layer is pasted as a reflective layer thereof, and the positioning is complicated at the time of pasting at the time of manufacture, and the productivity is inferior.

  The present invention is for solving the above-mentioned problems relating to the productivity of security media. The invention according to claim 1 is a cholesteric with volume hologram having a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer. A method for producing a liquid crystal medium, the step of forming a volume hologram layer on a first substrate, the step of forming a cholesteric liquid crystal layer on the volume hologram layer, and the step of peeling the first substrate And a step of forming an adhesive layer on the surface of the volume hologram layer from which the first substrate has been peeled, and a step of providing a second substrate on the adhesive layer.

  The invention according to claim 2 is a method of manufacturing a cholesteric liquid crystal medium with a volume hologram having a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer, wherein the volume hologram layer is formed on a first substrate. And a step of forming a cholesteric liquid crystal layer on the volume hologram layer, and a step of forming an adhesive layer on the surface of the first base material on which the volume hologram layer is not formed. It is characterized by that.

  The invention according to claim 3 is a method of manufacturing a cholesteric liquid crystal medium with a volume hologram having a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer, wherein the volume hologram layer is formed on a first substrate. A step of forming a cholesteric liquid crystal layer on the volume hologram layer, a step of peeling the first substrate, and heat sealing the surface of the volume hologram layer from which the first substrate has been peeled And a step of forming a layer.

  The invention according to claim 4 is the method for producing a cholesteric liquid crystal medium with a volume hologram according to claim 3, characterized in that it includes a step of providing a second base material on the heat seal layer.

  According to the present invention, a cholesteric liquid crystal medium with a volume hologram having a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer that are highly reliable in terms of security can be efficiently produced without requiring complicated steps such as alignment. can do.

I. Formation of Hologram Layer Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of the process of manufacturing a cholesteric liquid crystal medium with a volume hologram according to the present invention. As shown in FIG. 1, in the method for producing a cholesteric liquid crystal medium with a volume hologram according to the present invention, a substrate 1 is first prepared and a volume hologram layer 2 is formed thereon. It is not particularly limited as long as the layer can be formed and has a certain degree of mechanical strength. For example, a PET film, a polyvinyl chloride (PVC) film, a polyvinylidene chloride film, a polyethylene film, a polypropylene film, Polycarbonate film, cellophane film, acetate film, nylon film, polyvinyl alcohol film, polyamide film, polyamideimide film, ethylene-vinyl alcohol copolymer film, polymethyl methacrylate (PMMA) film, polyethersulfone film A polyether ether ketone (PEEK) film or the like can be used. Further, the thickness of such a substrate can be selected as appropriate, but is usually in the range of 5 μm to 200 μm, preferably 10 μm to 50 μm.

  The volume hologram layer 2 is formed by applying a composition in which each component described later is mixed on the substrate 1 by a general coating means such as a spin coater, gravure coater, comma coater, bar coater, etc. Dry according to.

  A conventionally known volume hologram recording material can be used as the hologram material. Specific examples include silver salt sensitive materials, dichromated gelatin, photocrosslinked polymers, and photopolymers. In particular, a photopolymer can produce a volume hologram only by a dry process as compared with other materials, and is an excellent material for mass production.

  The photopolymer used for the hologram material has at least one photopolymerizable compound and a photopolymerization initiator. Hereinafter, each constituent material of the photopolymer for volume hologram recording will be described.

1. Photopolymerizable compound The photopolymerizable compound used in the present invention will be described. The photopolymerizable compound in the present invention may be a radical photopolymerizable compound or a cationic photopolymerizable compound. Hereinafter, the description will be divided into a photoradical polymerizable compound and a photocationic polymerizable compound.

a. Photoradical Polymerizable Compound The photoradical polymerizable compound used in the present invention is, for example, a photoradical described later by laser irradiation or the like when forming a volume hologram using the volume hologram resin composition of the present invention. The compound is not particularly limited as long as it is a compound that is polymerized by the action of active radicals generated from the polymerization initiator, but a compound having at least one addition-polymerizable ethylenically unsaturated double bond can be used. . For example, an unsaturated carboxylic acid, an unsaturated carboxylate, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, an amide bond between an unsaturated carboxylic acid and an aliphatic polyhydric amine compound, and the like can be given. . Specific examples of the monomer of the ester of the unsaturated carboxylic acid and the aliphatic polyhydric alcohol compound are shown below.

  Acrylic esters include ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylol Methylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate Dipentaerythritol diacrylate, Pentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, 2-phenoxyethyl Acrylate, phenol ethoxylate monoacrylate, 2- (p-chlorophenoxy) ethyl acrylate, p-chlorophenyl acrylate, phenyl acrylate, 2-phenylethyl acrylate, (2-acryloxyethyl) ether of bisphenol A, ethoxylated bisphenol A diacrylate, 2- (1-naphthy Oxy) ethyl acrylate, o-biphenyl acrylate, 9,9-bis (4-acryloxydiethoxyphenyl) fluorene, 9,9-bis (4-acryloxytriethoxyphenyl) fluorene, 9,9-bis (4- Acryloxydipropoxyphenyl) fluorene, 9,9-bis (4-acryloxyethoxy-3-methylphenyl) fluorene, 9,9-bis (4-acryloxyethoxy-3-ethylphenyl) fluorene, 9,9- Examples thereof include bis (4-acryloxyethoxy-3,5-dimethyl) fluorene.

  A sulfur-containing acrylic compound can also be used. For example, 4,4′-bis (β-acryloyloxyethylthio) diphenyl sulfone, 4,4′-bis (β-acryloyloxyethylthio) diphenyl ketone, 4,4′-bis (β-acryloyloxyethylthio) 3,3 ′, 5,5′-tetrabromodiphenyl ketone, 2,4-bis (β-acryloyloxyethylthio) diphenyl ketone and the like.

  Further, as the methacrylic acid ester, among the compound names exemplified in the above-mentioned acrylic acid ester, “acrylate” is converted to “methacrylate”, “acryloxy” is converted to “methacryloxy”, and “acryloyl” is converted to “methacryloyl”. The exemplified compounds are exemplified.

  Moreover, the said radical photopolymerizable compound may be used 1 type or in combination of 2 or more types.

b. Photocationic Polymerizable Compound The photocationic polymerizable compound used in the present invention is a compound that undergoes cation polymerization by Bronsted acid or Lewis acid generated by decomposition of a photocationic polymerization initiator described later upon energy irradiation. For example, cyclic ethers such as epoxy ring and oxetane ring, thioethers, vinyl ethers and the like can be mentioned.

  Examples of the compound containing the epoxy ring include polyalkylene glycol diglycidyl ether, bisphenol A diglycidyl ether, glycerin triglycidyl ether, diglycerol triglycidyl ether, diglycidyl hexahydrophthalate, trimethylolpropane diglycidyl ether, allyl glycidyl ether. , Phenyl glycidyl ether, cyclohexene oxide and the like.

  Moreover, the said photocationic polymerizable compound may be used 1 type or in combination of 2 or more types.

  Furthermore, the photo radical polymerizable compound and the photo cation polymerizable compound may be used alone or in combination of two or more.

  Here, when forming a volume hologram using the resin composition for volume holograms, for example, by irradiating a laser to the shape of the target image to polymerize the photo radical polymerizable compound, the entire surface is energized. Is performed by polymerizing an uncured substance such as a photocationically polymerizable compound. It should be noted that the laser used to form an image and the energy irradiated with energy on the entire surface are usually of different wavelengths, and the photocationically polymerizable compound used in the present invention is, for example, a laser that forms an image. It is preferable that the compound does not polymerize.

  In addition, such a photo-cationic polymerizable compound is preferably in a liquid state at normal temperature because the polymerization of the photoradical polymerizable compound is preferably performed in a composition having a relatively low viscosity.

c. Others The photopolymerizable compound used in the present invention may be used in a proportion of 10 to 1000 parts by weight, preferably 10 to 300 parts by weight, based on 100 parts by weight of the binder resin described below.

  Here, the volume hologram forms an interference fringe by polymerizing a photopolymerizable compound with, for example, laser light or light having excellent coherence, and forms an image. Accordingly, when the photopolymerizable compound and the photocationically polymerizable compound are contained in the volume hologram resin composition, those having different refractive indexes are selected and used, The rate may be large. In the present invention, the average refractive index of the photoradically polymerizable compound is preferably larger than that of the photocationically polymerizable compound from the viewpoint of material selectivity. Specifically, the average refractive index is 0.02. It is preferable that it is larger. This is because when the difference in the average refractive index between the photo radical polymerizable compound and the photo cationic polymerizable compound is lower than the above value, the refractive index modulation becomes insufficient, and it is difficult to form a high-definition image. Because there is a possibility of becoming. The average refractive index here means the average value of the refractive index measured for the polymer after polymerizing the photocationically polymerizable compound or the photoradical polymerizable compound. The refractive index of the present invention is a value measured by an Abbe refractometer.

2. Photopolymerization initiator Next, the photopolymerization initiator used in the present invention will be described. As a photoinitiator in this invention, a kind changes with photopolymerizable compounds mentioned above. That is, when the photopolymerizable compound is a photoradical polymerizable compound, the photopolymerization initiator selects a photoradical polymerization initiator, and when the photopolymerizable compound is a photocationic polymerizable compound, the photopolymerization initiator. It is necessary to select a photocationic polymerization initiator. Hereinafter, the radical photopolymerization initiator and the photocationic polymerization initiator will be described separately.

a. Photoradical polymerization initiator As the photoradical polymerization initiator used in the present invention, an active radical is generated by, for example, a laser irradiated when the volume hologram layer 2 is formed using the resin composition for volume hologram. And it will not specifically limit if it is an initiator which can superpose | polymerize the said photoradically polymerizable compound. For example, imidazole derivatives, bisimidazole derivatives, N-aryl glycine derivatives, organic azide compounds, titanocenes, aluminate complexes, organic peroxides, N-alkoxypyridinium salts, thioxanthone derivatives, and the like can be used. Specifically, 1,3-di (t-butyldioxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetrakis (t-butyldioxycarbonyl) benzophenone, 3-phenyl-5-isoxazolone, 2-mercaptobenzimidazole, bis (2,4,5-triphenyl) imidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name Irgacure 651, manufactured by Ciba Specialty Chemicals) ), 1-hydroxy-cyclohexyl-phenyl-ketone (trade name Irgacure 18)
4, Ciba Specialty Chemicals Co., Ltd.), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name Irgacure 369, Ciba Specialty Chemicals Co., Ltd.) ), Bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium (trade name Irgacure 784, Ciba Specialty)・ Chemicals Co., Ltd.).

b. Photocationic polymerization initiator The photocationic polymerization initiator used in the present invention is not particularly limited as long as it generates Bronsted acid or Lewis acid by energy irradiation and polymerizes the photocationic polymerizable compound. is not. When the volume hologram resin composition contains a radical photopolymerizable compound and a cationic photopolymerizable compound, the cationic photopolymerizable compound is a polymer that specifically polymerizes the radical photopolymerizable compound, for example, light having excellent laser or coherence. It is preferable that the light is exposed to the energy irradiated to the entire surface after the reaction. Thereby, when the photo radical polymerizable compound is polymerized, the photo cation polymerizable compound can be allowed to exist with little reaction, and a large refractive index modulation in the volume hologram can be obtained.

  Specifically, sulfonic acid ester, imide sulfonate, dialkyl-4-hydroxysulfonium salt, arylsulfonic acid-p-nitrobenzyl ester, silanol-aluminum complex, (η6-benzene) (η5-cyclopentadienyl) iron ( II) etc. are exemplified. Furthermore, benzoin tosylate, 2,5-dinitrobenzyl tosylate, N-tosiphthalimide and the like can also be used.

c. Others In the present invention, as a radical photopolymerization initiator and a photocationic polymerization initiator, aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, aromatic phosphonium salts, triazine compounds, iron Examples include arene complexes. Specifically, chlorides of iodonium such as diphenyliodonium, ditolyliodonium, bis (pt-butylphenyl) iodonium, bis (p-chlorophenyl) iodonium, bromide, borofluoride, hexafluorophosphate, hexafluoroantimony Iodonium salts such as nate salts, chlorides of sulfonium such as triphenylsulfonium, 4-t-butyltriphenylsulfonium, tris (4-methylphenyl) sulfonium, bromides, borofluoride salts, hexafluorophosphate salts, hexafluoroantimonate salts Sulfonium salts such as 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2-methyl -4,6- Scan (trichloromethyl) -1,3,5-2,4,6-substituted-1,3,5-triazine compounds such as triazine, and the like.

  Moreover, said photoinitiator may be used 1 type or in combination of 2 or more types.

  Further, the photopolymerization initiator is used in a proportion of 0.1 to 20 parts by weight, preferably 5 to 15 parts by weight, based on 100 parts by weight of the binder resin described later.

3. Additives Next, additives that can be added to the volume hologram resin composition will be described.

a. Sensitizing Dye In the present invention, the volume hologram tree composition preferably contains a sensitizing dye. Many of the above photopolymerizable compounds and photopolymerization initiators are active with respect to ultraviolet rays, but addition of a sensitizing dye makes them also active with visible light and can record interference fringes using visible laser light. This is because it becomes possible.

  Such a sensitizing dye is selected in consideration of the wavelength of the laser beam used when recording interference fringes, but is not particularly limited. For example, thiopyrylium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, coumarin dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, pyrylium System dyes, cyclopentanone dyes, cyclohexanone dyes, and the like can be used.

  Examples of the cyanine dye and merocyanine dye include 3,3′-dicarboxyethyl-2,2′-thiocyanine bromide, 1-carboxymethyl-1′-carboxyethyl-2,2′-quinocyanine bromide, 1 , 3′-diethyl-2,2′-quinothiocyanine iodide, 3-ethyl-5-[(3-ethyl-2 (3H) -benzothiazolidelidene) ethylidene] -2-thioxo-4-oxazolidine, etc. Can be given.

  Examples of the coumarin dyes and ketocoumarin dyes include 3- (2′-benzimidazole) 7-N, N-diethylaminocoumarin, 3,3′-carbonylbis (7-diethylaminocoumarin), and 3,3′-. Examples thereof include carbonyl biscoumarin, 3,3′-carbonyl bis (5,7-dimethoxycoumarin), 3,3′-carbonyl bis (7-acetoxycoumarin) and the like.

  A sensitizing dye having an absorption wavelength in the visible light region is required to have high transparency when, for example, a hologram is used as an optical element. Those which become colorless upon being decomposed by irradiation are preferred. As such a sensitizing dye, the above-mentioned cyanine dye is preferably used.

  The sensitizing dye is used in an amount of 0.01 to 10 parts by weight, preferably 0.01 to 2 parts by weight, based on 100 parts by weight of the binder resin described below.

b. Binder Resin In the present invention, the volume hologram resin composition preferably contains a binder resin. By containing the binder resin, the film formability and the film thickness uniformity can be improved, and the recorded interference fringes can be stably present.

  Examples of such a binder resin include polymethacrylic acid ester or a partially hydrolyzed product thereof, polyvinyl acetate or a hydrolyzed product thereof, polyvinyl alcohol or a partially acetalized product thereof, triacetyl cellulose, polyisoprene, polybutadiene, polychloroprene, and silicone. Rubber, polystyrene, polyvinyl butyral, polyvinyl chloride, polyarylate, chlorinated polyethylene, chlorinated polypropylene, poly-N-vinyl carbazole or derivatives thereof, poly-N-vinyl pyrrolidone or derivatives thereof, co-use of styrene and maleic anhydride Examples thereof include polymers or half esters thereof. And at least one monomer selected from the group consisting of copolymerizable monomers such as acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylamide, acrylonitrile, ethylene, propylene, vinyl chloride, and vinyl acetate. A copolymer obtained by polymerizing can also be used. Moreover, the copolymer formed by polymerizing the monomer which has a functional group which can be thermoset or photocured in a side chain can also be used. Furthermore, 1 type, or 2 or more types of mixtures can also be used.

  As the binder resin, an oligomer type curable resin may be used. Examples thereof include epoxy compounds produced by condensation reaction of various phenolic compounds such as bisphenol A, bisphenol S, novolak, o-cresol novolak, p-alkylphenol novolak and epichlorohydrin.

  Furthermore, as the binder resin, an organic-inorganic hybrid polymer using a sol-gel reaction can also be used. Examples thereof include a copolymer of an organometallic compound having a polymerizable group represented by the following general formula (1) and a vinyl monomer.

Rm M (OR ') n (1)
(Where M is a metal such as Si, Ti, Zr, Zn, In, Sn, Al, Se, R is a vinyl group or (meth) acryloyl group having 1 to 10 carbon atoms, and R 'is 1 to 10 carbon atoms. And m + n is the valence of the metal M).

  Examples of organometallic compounds when Si is used as the metal M include vinyltriethoxysilane, vinyltrimethoxysilane, vinyltributoxysilane, vinyltriallyloxysilane, vinyltetraethoxysilane, vinyltetramethoxysilane, acryloxy Examples thereof include propyltrimethoxysilane and methacryloxypropyltrimethoxysilane.

  Examples of the vinyl monomer include acrylic acid, acrylic acid ester, methacrylic acid, and methacrylic acid ester.

  Here, the volume hologram is formed by recording interference fringes as refractive index modulation or transmittance modulation. Therefore, it is preferable that the refractive index difference between the binder resin and the photopolymerizable compound is large. In the present invention, in order to increase the refractive index difference between the binder resin and the photopolymerizable compound, an organometallic compound represented by the following general formula (2) may be added to the volume hologram resin composition. it can.

M (OR ") k (2)
(Here, M represents a metal such as Ti, Zr, Zn, In, Sn, Al, Se, R ″ represents an alkyl group having 1 to 10 carbon atoms, and k represents the valence of the metal M).

  When the compound represented by the formula (2) is added to the volume hologram resin composition, a network structure is formed with the binder resin by a sol-gel reaction in the presence of water and an acid catalyst. It has the effect of improving the toughness and heat resistance of the film. Therefore, in order to increase the refractive index difference from the photopolymerizable compound, it is preferable to use a metal M having a high refractive index.

  The binder resin is usually used in the volume hologram composition in the range of 15 to 50% by weight, preferably in the range of 20 to 40% by weight.

  Next, formation of the volume hologram layer 2 of the present invention will be described.

  In the present invention, the volume hologram layer 2 is formed by first coating the volume hologram resin composition on the substrate 1 by a general coating means, and drying it as necessary. 2.

  Next, the above-mentioned photopolymerizable compound is polymerized on the volume hologram layer 2 by exposure with light having excellent coherence property (for example, light having a wavelength of 300 nm to 1200 nm), which is a laser beam that is usually used in a holographic exposure apparatus. Record the interference fringes of the target image. Thereby, the volume hologram layer 2 is formed.

  The volume hologram resin composition may be used with a solvent, if necessary, at the time of coating. Examples of such solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl acetate, 1,4- Dioxane, 1,2-dichloroethane, dichloromethane, chloroform, methanol, ethanol, isopropanol and the like can be used. These solvents may be used alone or in combination of two or more.

  Moreover, as a coating method of the volume hologram resin composition, methods such as a spin coater, a gravure coater, a comma coater, and a bar coater can be used.

The coating amount of the volume hologram resin composition is appropriately selected depending on the use and type of the volume hologram layer 2, but is usually in the range of 1 g / m ^{2 to} 100 g / m ² , preferably ² g / m ^2. m ^{2 to} 40 g / m ² , and the film thickness of the volume hologram layer 2 is usually 1 μm to 100 μm, preferably 2 μm to 40 μm. Furthermore, the film thickness of the volume hologram layer 2 formed by curing the volume hologram resin composition is preferably in the range of 1 to 100 μm, more preferably 10 to 40 μm.

  The above-mentioned volume hologram layer 2 is polymerized with the above-described photopolymerizable compound by exposure with light having excellent coherence (for example, light having a wavelength of 300 nm to 1200 nm), and the laser light normally used in a holographic exposure apparatus Record the interference fringes of the image. As the laser beam, a visible laser, for example, an argon ion laser (458 nm, 488 nm, 514.5 nm), a krypton ion laser (647.1 nm), a helium-neon laser (633 nm), a YAG laser (532 nm), or the like is used. Can do.

  As a method for recording the interference fringes of the image, a conventionally known method can be used. For example, an original plate is brought into close contact with the volume hologram layer 2, and interference fringes of an image are recorded by performing interference exposure from the base film side using ionizing radiation such as visible light, ultraviolet light, or an electron beam.

Further, in order to accelerate the refractive index modulation and complete the polymerization reaction of the photopolymerizable compound or the like, after the interference exposure, treatments such as full exposure with ultraviolet rays and heating can be appropriately performed. It should be noted that a protective layer made of PET or the like is provided on the surface of the volume hologram layer 2 in order to protect the volume hologram layer 2 before performing the process such as the entire surface exposure or heating with ultraviolet rays. Also good.
II. Formation of Cholesteric Liquid Crystal Layer A cholesteric liquid crystal layer 3 is then formed on the volume hologram layer 2 formed as described above. FIG. 2 shows a cross-sectional structure at the time of manufacturing a cholesteric liquid crystal medium with a volume hologram after the cholesteric liquid crystal layer 3 is formed.

  In addition, when forming the cholesteric liquid crystal layer 3, the alignment film A may be provided in advance or may be omitted. If the alignment film A is provided, the liquid crystal applied on the alignment film A is in a planar alignment state, and without the alignment film A, the liquid crystal is not in such an alignment state. If the alignment film A is provided, a label (medium) that can be reflected like a mirror surface can be manufactured, and if there is no alignment film A, it depends on the self-orientation by the liquid crystal itself, so it is scattering Thus, a label (medium) having good visibility even when viewed from a slight angle can be produced. In addition, even in the case of a scattering cholesteric liquid crystal layer, an alignment film may be provided. By controlling the degree of scattering arbitrarily depending on the molecular alignment control force of the alignment film, scattering characteristics suitable for arbitrary viewing conditions are given. can do.

Hereinafter, details of each process (application process, alignment process process, and curing process process) for laminating (adhering) the cholesteric liquid crystal layer 3 will be described.
(Coating process)
In the coating step, a cholesteric liquid crystal layer is formed by coating a liquid crystalline composition exhibiting cholesteric regularity. At this time, any existing method can be used as a method of applying the liquid crystalline composition. Specifically, a roll coating method, a gravure coating method, a bar coating method, a slide coating method, a die coating method, a slit coating method, a dipping method, a screen printing method, or the like can be used. In addition, a coating by a so-called roll to roll system can be used.

  In addition, as a liquid crystalline composition to be applied, chiral nematic liquid crystal or cholesteric liquid crystal exhibiting cholesteric regularity can be used. Such a material is not particularly limited as long as it is a liquid crystal material capable of forming a cholesteric liquid crystal structure, and in particular, a polymerizable liquid crystal material having a polymerizable functional group at both ends of the molecule. It is preferable for obtaining an optically stable cholesteric liquid crystal layer 3 after curing.

  Further, in the coating process, by applying the coating to only a part, for example, a cholesteric liquid crystal layer in which a pattern such as letters and figures is formed can be realized.

  Hereinafter, the case where a chiral nematic liquid crystal is used as the liquid crystalline composition will be described as an example. The chiral nematic liquid crystal is a mixture of a polymerizable liquid crystal material exhibiting nematic regularity and a chiral agent. Here, the chiral agent is for controlling the helical pitch length of the polymerizable liquid crystal material exhibiting nematic regularity so that the liquid crystalline composition exhibits cholesteric regularity as a whole. In addition, a photopolymerization initiator and an appropriate additive are added to such a liquid crystalline composition.

  Examples of polymerizable liquid crystal materials exhibiting nematic regularity include, for example, compounds represented by the following general formula (1) and compounds represented by the following formulas (2-i) to (2-xi). Can be mentioned. These compounds can be used alone or in combination.

上記一般式（１）において、Ｒ１及びＲ２はそれぞれ水素又はメチル基を示すが、液晶相を示す温度範囲の広さからＲ１及びＲ２はともに水素であることが好ましい。Ｘは水素、塩素、臭素、ヨウ素、炭素数１〜４のアルキル基、メトキシ基、シアノ基、ニトロ基のいずれであっても差し支えないが、塩素又はメチル基であることが好ましい。また、上記一般式（１）において、分子鎖両端の（メタ）アクリロイロキシ基と芳香環とのスペーサーであるアルキレン基の鎖長を示すａ及びｂは、それぞれ個別に２〜１２の範囲で任意の整数をとり得るが、４〜１０の範囲であることが好ましく、６〜９の範囲であることがさらに好ましい。ａ＝ｂ＝０である一般式（１）の化合物は、安定性に乏しく、加水分解を受けやすい上に、化合物自体の結晶性が高い。また、ａ及びｂがそれぞれ１３以上である一般式（１）の化合物は、アイソトロピック転移温度（ＴＩ）が低い。この理由から、これらの化合物はどちらも液晶相を示す温度範囲が狭く好ましくない。

In the general formula (1), R1 and R2 each represent hydrogen or a methyl group, but it is preferable that both R1 and R2 are hydrogen because of the wide temperature range showing the liquid crystal phase. X may be hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, or a nitro group, but is preferably a chlorine or methyl group. Moreover, in the said General formula (1), a and b which show the chain length of the alkylene group which is a spacer of the (meth) acryloyloxy group and aromatic ring of the molecular chain both ends are arbitrary in the range of 2-12, respectively. Although it can take an integer, it is preferably in the range of 4 to 10, and more preferably in the range of 6 to 9. The compound of the general formula (1) in which a = b = 0 is poor in stability, is susceptible to hydrolysis, and has high crystallinity. In addition, the compound of the general formula (1) in which a and b are each 13 or more has a low isotropic transition temperature (TI). For this reason, both of these compounds are not preferable because the temperature range in which the liquid crystal phase is exhibited is narrow.

  In the above, examples of polymerizable liquid crystal monomers have been described as polymerizable liquid crystal materials exhibiting nematic regularity, but not limited thereto, polymerizable liquid crystal oligomers, polymerizable liquid crystal polymers, liquid crystal polymers, etc. It is also possible to use it. Such a polymerizable liquid crystal oligomer, polymerizable liquid crystal polymer and liquid crystal polymer can be appropriately selected from those conventionally proposed.

  On the other hand, a chiral agent is a low molecular compound having an optically active site, and is mainly a compound having a molecular weight of 1500 or less. The chiral agent is mainly used for the purpose of inducing a helical structure in the positive uniaxial nematic regularity expressed by the polymerizable liquid crystal material exhibiting nematic regularity. As long as this purpose is achieved, it is compatible with a polymerizable liquid crystal material exhibiting nematic regularity in a solution state or a molten state, without impairing the liquid crystal property of the polymerizable liquid crystal material exhibiting nematic regularity, The kind of the low molecular compound as the chiral agent is not particularly limited as long as it can induce a desired helical structure.

  In addition, the chiral agent used for inducing a helical structure in the liquid crystal in this way needs to have at least some chirality in the molecule. Accordingly, the chiral agent used here includes, for example, a compound having one or more asymmetric carbons, a compound having an asymmetric point on a heteroatom such as a chiral amine or chiral sulfoxide, or a cumulene. And compounds having an optically active moiety having axial asymmetry such as binaphthol. More specifically, a commercially available chiral nematic liquid crystal (for example, chiral dopant liquid crystal S-811 (manufactured by Merck)) can be mentioned.

However, depending on the properties of the selected chiral agent, the nematic regularity formed by the polymerizable liquid crystal material exhibiting nematic regularity, the orientation deterioration, or the liquid crystallinity when the chiral agent is non-polymerizable. There exists a possibility of causing the fall of the sclerosis | hardenability of a composition, and the fall of the reliability of the film after hardening. Furthermore, the use of a large amount of a chiral agent having an optically active site leads to an increase in the cost of the liquid crystal composition. Therefore, when a cholesteric liquid crystal layer having a cholesteric regularity with a short helical pitch length is formed, a chiral agent having a large effect of inducing a helical structure is used as a chiral agent having an optically active site to be contained in the liquid crystalline composition. Specifically, it is preferable to use a low molecular compound having axial asymmetry in the molecule as represented by the following general formula (3), (4) or (5).

上記一般式（３）又は（４）において、Ｒ４は水素又はメチル基を示す。Ｙは上記に示す式（ｉ）〜（ｘｘｉｖ）の任意の一つであるが、中でも、式（ｉ）、（ｉｉ）、（ｉｉｉ）、（ｖ）及び（ｖｉｉ）のいずれか一つであることが好ましい。また、アルキレン基の鎖長を示すｃ及びｄは、それぞれ個別に２〜１２の範囲で任意の整数をとり得るが、４〜１０の範囲であることが好ましく、６〜９の範囲であることがさらに好ましい。ｃ又はｄの値が０又は１である上記一般式（３）又は（４）の化合物は、安定性に欠け、加水分解を受けやすく、結晶性も高い。一方、ｃ又はｄの値が１３以上である化合物は融点（Ｔｍ）が低い。これらの化合物では、ネマチック規則性を示す重合性の液晶材料との間の相溶性が低下し、濃度によっては相分離などが起きるおそれがある。

In the above general formula (3) or (4), R4 represents hydrogen or a methyl group. Y is any one of formulas (i) to (xxiv) shown above, and among them, any one of formulas (i), (ii), (iii), (v), and (vii) Preferably there is. Moreover, although c and d which show the chain length of an alkylene group can each take arbitrary integers in the range of 2-12, it is preferable that it is the range of 4-10, and is the range of 6-9. Is more preferable. The compound of the above general formula (3) or (4) in which the value of c or d is 0 or 1 lacks stability, is susceptible to hydrolysis, and has high crystallinity. On the other hand, a compound having a value of c or d of 13 or more has a low melting point (Tm). In these compounds, compatibility with a polymerizable liquid crystal material exhibiting nematic regularity is lowered, and phase separation or the like may occur depending on the concentration.

  In addition, such a chiral agent does not need to have polymerizability in particular. However, when the chiral agent has polymerizability, it is polymerized with a polymerizable liquid crystal material exhibiting nematic regularity, and the cholesteric regularity is stably fixed, so in terms of thermal stability, etc. Highly preferred. In particular, it is preferable to have a polymerizable functional group at both ends of the molecule in order to obtain a cholesteric liquid crystal layer 3 having good heat resistance.

  The amount of the chiral agent contained in the liquid crystal composition is determined in consideration of the ability to induce a helical structure, the cholesteric liquid crystal structure of the finally obtained cholesteric liquid crystal layer, and the like. Specifically, although it varies greatly depending on the material of the liquid crystal composition used, 0.01 to 60 parts by weight, preferably 0.1 to 40 parts by weight, per 100 parts by weight of the total amount of the liquid crystal composition. More preferably, it is selected in the range of 0.5 to 30 parts by weight, most preferably 1 to 20 parts by weight. When the content of the chiral agent is less than the above range, sufficient cholesteric regularity may not be imparted to the liquid crystal composition. When the content exceeds the above range, the alignment of the liquid crystal molecules is inhibited. There is a risk of adverse effects when cured by actinic radiation.

  Although the liquid crystalline composition can be applied as it is, it can be made into an ink by dissolving it in an appropriate solvent such as an organic solvent in order to adjust the viscosity to a coating apparatus or to obtain a good alignment state. Also good.

Such a solvent is not particularly limited as long as it can dissolve the polymerizable liquid crystal material as described above, but preferably does not erode the coating layer. Specific examples include acetone, 3-methoxybutyl acetate, diglyme, cyclohexanone, tetrahydrofuran, toluene, xylene, chlorobenzene, methylene chloride, methyl ethyl ketone, and the like. The degree of dilution of the polymerizable liquid crystal material is not particularly limited, but it is 5 to 50%, more preferably 10 in view of the fact that the liquid crystal itself is a material with low solubility and high viscosity. It is preferable to dilute to about 30%.
(Orientation process)
After the liquid crystal composition is applied and the cholesteric liquid crystal layer is formed in the coating process described above, the liquid crystal in the cholesteric liquid crystal layer is maintained at a predetermined temperature at which the cholesteric liquid crystal structure is expressed in the alignment treatment process. Orient molecules.

  Note that the cholesteric liquid crystal structure of the cholesteric liquid crystal layer 3 to be finally obtained in the present embodiment has an alignment state in which the directions of the helical axes of the plurality of helical structure regions vary within the layer, and planar alignment. In some cases, orientation processing is necessary. That is, in the former, an alignment process that forms a plurality of helical structure regions in the cholesteric liquid crystal structure is necessary, and in the latter, an alignment process that forms a plurality of helical structure regions in the cholesteric liquid crystal structure; An alignment process is required to align the directors of liquid crystal molecules having a cholesteric liquid crystal structure in a certain direction.

  Further, by performing this alignment treatment on only a part of the cholesteric liquid crystal layer, for example, a cholesteric liquid crystal layer in which patterns such as letters and figures are formed can be expressed.

  Here, when the cholesteric liquid crystal layer 3 is maintained at a predetermined temperature at which the cholesteric liquid crystal structure is developed, the cholesteric liquid crystal layer exhibits a liquid crystal phase, and the director of the liquid crystal molecules continuously rotates due to the self-integrating action of the liquid crystal molecules themselves. A spiral structure is formed. If the cholesteric liquid crystal layer 3 is not made diffusive, the directors of liquid crystal molecules having a cholesteric liquid crystal structure are aligned in a certain direction. And the cholesteric liquid crystal structure expressed in such a liquid crystal phase can be fixed by curing the cholesteric liquid crystal layer by a method as described later.

In addition, when the solvent is contained in the liquid crystalline composition apply | coated on the cholesteric liquid crystal layer 3, such an alignment process process is normally performed with the drying process for removing a solvent. In order to remove the solvent, a drying temperature of 40 to 120 ° C., preferably 60 to 100 ° C. is suitable. The drying time (heating time) exhibits a cholesteric liquid crystal structure, and the solvent is substantially removed. For example, it is preferably 15 to 600 seconds, and more preferably 30 to 180 seconds. In addition, when it turns out that an orientation state is inadequate after drying, it is good to extend a heating time suitably. In addition, when using the vacuum drying method in such a drying process, it is preferable to perform a separate heat treatment for the alignment process.
(Curing process)
After aligning the liquid crystal molecules in the cholesteric liquid crystal layer in the alignment treatment step described above, in the curing treatment step, the cholesteric liquid crystal layer is cured to fix the cholesteric liquid crystal structure expressed in the liquid crystal phase.

  Here, as a method used in the curing treatment step, (1) a method of drying a solvent in the liquid crystalline composition, (2) a method of polymerizing liquid crystal molecules in the liquid crystalline composition by heating, (3) radiation A method of polymerizing liquid crystal molecules in the liquid crystalline composition by irradiation of (4) and (4) a method combining these methods can be used.

  Among these, the method (1) is a method suitable when a liquid crystal polymer is used as a polymerizable liquid crystal material exhibiting nematic regularity contained in a liquid crystalline composition that is a material of a cholesteric liquid crystal layer. In this method, the liquid crystal polymer is applied in a state dissolved in a solvent such as an organic solvent. In this case, a solidified cholesteric liquid crystal having cholesteric regularity can be obtained simply by removing the solvent by a drying process. A layer is formed. In addition, about the kind of solvent, drying conditions, etc., what was described in the apply | coating process and orientation process mentioned above can be used.

  The method (2) is a method of curing the cholesteric liquid crystal layer by thermally polymerizing liquid crystal molecules in the liquid crystal composition by heating. In this method, the bonding state of the liquid crystal molecules changes depending on the heating (firing) temperature. Therefore, if there is temperature unevenness in the plane of the cholesteric liquid crystal layer during heating, physical properties such as film hardness and optical characteristics are uneven. Here, in order to keep the film hardness distribution within ± 10%, the heating temperature distribution is also preferably within ± 5%, and more preferably within ± 2%.

  The method for heating the formed cholesteric liquid crystal layer is not particularly limited as long as the uniformity of the heating temperature can be obtained, and it is held in close contact with the heat plate, or a slight air layer between the heat plate and the heat plate. The method of providing and holding | maintaining so that it may become parallel to a heat plate can be used. Further, it may be a method in which the entire specific space such as an oven is heated or passed through the apparatus. In the case of using a film coater or the like, it is preferable to lengthen the drying zone so that a sufficient heating time can be taken.

  The heating temperature generally requires a high temperature of 100 ° C. or higher, but is preferably about 150 ° C. due to the heat resistance of the substrate 1. However, if a film or the like specialized for heat resistance is used as the material of the support substrate 1, heating at a high temperature of 150 ° C. or higher is also possible.

  The method (3) is a method of curing the cholesteric liquid crystal layer by photopolymerizing liquid crystal molecules in the liquid crystalline composition by irradiation with radiation. In this method, an electron beam, ultraviolet rays, or the like can be appropriately used as radiation according to conditions. Usually, ultraviolet rays are preferably used from the viewpoint of easiness of the apparatus, and the wavelength is 250 to 400 nm. Here, when ultraviolet rays are used, it is preferable that a photopolymerization initiator is added to the liquid crystalline composition.

  Examples of the photopolymerization initiator added to the liquid crystal composition include benzyl (also referred to as bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, benzoyl methyl benzoate, 4-benzoyl-4'- Methyl diphenyl sulfide, benzyl methyl ketal, dimethylaminomethyl benzoate, 2-n-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3'-dimethyl-4-methoxybenzophenone, methylobenzoylpho Mate, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1- ON, 1- ( -Dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) 2-hydroxy-2-methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxy Examples include thioxanthone. In addition to the photopolymerization initiator, it is also possible to add a sensitizer as long as the object of the present invention is not impaired.

  In addition, the addition amount of the photopolymerization initiator added to the liquid crystalline composition is 0.01 to 20% by weight, preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight. Preferably there is.

A single cholesteric liquid crystal layer 3 can be laminated (fixed) on the volume hologram layer 2 by performing the above-described series of steps (coating step, alignment step and curing step).
III. Label processing / transfer foil processing The volume hologram layer 2 and the cholesteric liquid crystal layer 3 formed as described above are subjected to label processing or transfer foil processing to facilitate handling. FIG. 3 shows a cross-sectional structure of a cholesteric liquid crystal medium with a volume hologram after label processing or transfer foil processing. As a processing method, when label processing is adopted, 4 is an adhesive layer, and when adopting transfer foil processing, 4 is a heat seal layer. In FIG. 2, first, the substrate 1 is peeled from the volume hologram layer 2 and the cholesteric liquid crystal layer 3, and an adhesive layer (or heat seal layer) 4 and a new substrate 5 are provided instead of the peeled substrate 1. The state shown in FIG.

  Since the base material 5 is peeled off when the cholesteric liquid crystal medium with a volume hologram is applied to an adherend, the peelability from the adhesive layer (or heat seal layer) 4 is moderate, and a certain degree of machine What has sufficient strength may be used, and is not particularly limited. For example, PET film, polyvinyl chloride (PVC) film, polyvinylidene chloride film, polyethylene film, polypropylene film, polycarbonate film, cellophane film, acetate film, nylon film, polyvinyl alcohol film, polyamide film, polyamideimide film, ethylene-vinyl alcohol A transparent resin film such as a copolymer film, a polymethyl methacrylate (PMMA) film, a polyether sulfone film, or a polyether ether ketone (PEEK) film can be used.

Further, the thickness of such a substrate film is appropriately selected according to the use or type of the label or transfer foil, but is usually in the range of 2 μm to 200 μm, preferably 10 μm to 50 μm. The
(Label processing)
The pressure-sensitive adhesive layer 4 when processing a cholesteric liquid crystal medium with a volume hologram into a label form will be described. The pressure-sensitive adhesive layer 4 adheres the cholesteric liquid crystal medium with a volume hologram and an adherend. For example, an acrylic resin, an acrylate resin, or a copolymer thereof, a styrene-butadiene copolymer, a natural rubber, casein, Gelatin, rosin ester, terpene resin, phenolic resin, styrene resin, chromanindene resin, polyvinyl ether, silicone resin, etc., alpha-cyanoacrylate, silicone, maleimide, styrene, polyolefin, resorcinol, It is obtained using a polyvinyl ether adhesive. As thickness of the adhesion layer 4, 4 micrometers-30 micrometers are preferable.
(Transfer foil processing)
Next, the heat seal layer 4 when processing a cholesteric liquid crystal medium with a volume hologram into a transfer foil will be described. The heat seal layer 4 is a layer that adheres the cholesteric liquid crystal medium with a volume hologram and the adherend by bringing the cholesteric liquid crystal medium with a volume hologram into close contact with the adherend when it is transferred onto the adherend by heat transfer and heating. is there.

Examples of such a heat-sensitive adhesive layer include ethylene-vinyl acetate copolymer resin (EVA), polyamide resin, polyester resin, polyethylene resin, ethylene-isobutyl acrylate copolymer resin, butyral resin, polyvinyl acetate, and copolymers thereof. Combined resin, cellulose resin, polymethyl methacrylate resin, polyvinyl ether resin, polyurethane resin, polycarbonate resin, polypropylene resin, epoxy resin, phenol resin, styrene butadiene styrene block copolymer (SBS), styrene isoprene styrene block copolymer Thermoplastic resins such as (SIS), styrene ethylene butylene styrene block copolymer (SEBS), and styrene ethylene propylene styrene block copolymer (SEPS) can be used. Among these, a layer that can be heat sealed at a temperature of 180 ° C. or lower is preferable. Further, the resin may have a heat-sensitive adhesive layer colored as necessary.
IV. Other processing treatments In addition to the above-described label processing / transfer foil processing, various processings as shown below and combinations of these processings can be appropriately employed in the present invention.
(Pre-processing 1 such as adhesive layer)
In the label processing / transfer foil processing described above, the base material 1 is peeled off from the volume hologram layer 2 and the cholesteric liquid crystal layer 3, and an adhesive layer (or heat seal layer) 4 is used instead of the peeled base material 1. In addition, a new base material 5 is sequentially provided, but a film having a three-layer structure of base material / adhesive layer (or heat seal layer) / separator film is prepared in advance, and the base material / adhesive layer ( Alternatively, if the separator film is peeled off from the film having a three-layer structure of the heat seal layer / separator film and the both are bonded together, the productivity of the cholesteric liquid crystal medium with volume hologram can be improved. it can.
(Pre-processing 2 such as adhesive layer)
The film having a three-layer structure of base material / adhesive layer (or heat seal layer) / separator film used in (preliminary processing 1 such as an adhesive layer) may have insufficient film strength and strength. In such a case, a five-layer film of base material / adhesive layer (or heat seal layer) / reinforcing base film / adhesive layer (or heat seal layer) / separator film may be used. As with the previous method, the separator is used while peeling the separator film.
(Protective layer processing)
In the present invention, a protective layer can be appropriately provided between necessary layers. Examples of protective layers include acrylic resins, vinyl chloride-vinyl acetate copolymer resins, polyester resins, polymethacrylate resins, polyvinyl chloride resins, cellulose resins, silicone resins, chlorinated rubber, casein, various surfactants, metal oxides The thing etc. which mixed 1 type (s) or 2 or more types from a thing etc. can be used. Among them, an acrylic resin having a molecular weight of about 20,000 to 100,000 is composed of an acrylic resin alone or an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin having a molecular weight of 8000 to 20000. Further, a polyester resin having a molecular weight of 1000 to 5000 is used as an additive. It is particularly preferable that the composition comprises ˜5% by weight. Further, as the protective layer, an ionizing radiation curable resin, a thermosetting resin, or a thermoplastic resin that reacts with ultraviolet rays or electron beams may be used.
(Peeling layer processing)
In the present invention, a release layer can be appropriately provided between layers that require good peelability. For the release layer, water-soluble resin, hydrophilic resin, wax, silicone wax, silicone resin, fluorine resin, acrylic resin, or the like is used. The thickness of the release layer is usually about 0.5 to 5 μm.
V. As described above, a cholesteric liquid crystal medium with a volume hologram processed into a label form or a transfer foil form is die-cut to be a final product.

(Example 1)
(1) Production of laminate 1 (untreated PET film 1 / volume hologram layer / untreated PET film 2) (see FIG. 4)
On untreated PET film 2 (Lumirror T60 (50 μm); manufactured by Toray Industries, Inc.), the following composition (volume hologram recording solution)
-Polymethyl methacrylate (weight average molecular weight 200,000) 100 parts by weight-9,9-bis (4-acryloxydiethoxyphenyl) fluorene 80 parts by weight-1,6-hexanediol diglycidyl ether 70 parts by weight-diphenyliodonium Hexafluoroantimonate 5 parts by weight 3,9-diethyl-3'-carboxymethyl-2,2'-thiacarbocyanine iodonium salt
1 part by weight / solvent (methyl ethyl ketone / 1-butanol = 1/1 (weight ratio)) After applying a volume hologram recording solution consisting of 200 parts by weight with an applicator to a film thickness of 10 μm after drying, 90 ° C. The volume hologram recording layer / untreated PET film 2 was obtained by drying in an oven. The volume hologram recording layer surface of the obtained laminate is brought into close contact with the hologram master, laser light (532 nm) is incident at 80 mJ / cm ² from the untreated PET film 2 side, and the volume hologram is applied to the volume hologram recording layer. Recorded. After recording, the laminate 1 having a reflection center wavelength of 530 nm is peeled off from the hologram master and laminated with an untreated PET film 1 (Lumirror T60 (50 μm)) on the volume hologram layer surface, followed by heating and ultraviolet fixing exposure. Got.
(2) Production of laminate 2 (cholesteric liquid crystal layer / volume hologram layer / untreated PET film 2) (see FIG. 5)
The untreated PET film 1 of the laminate 1 is peeled off, and the following composition (preparation of cholesteric liquid crystal solution) on the volume hologram layer surface
・ Main agent composed of UV-curable nematic liquid crystal (95.8 parts by weight)
・ Polymerizable chiral agent (4.2 parts by weight)
-Photopolymerization initiator (5 parts by weight; manufactured by Ciba Specialty Chemicals)
A cholesteric liquid crystal solution composed of cyclohexanone was applied by a bar coater so as to have a film thickness of 4 μm after drying, and then heated in an oven at 80 ° C. to perform alignment treatment (drying treatment).
(3) Production of laminate 3 (separator 1 / adhesive layer 1 / black PET film / adhesive layer 2 / separator 2) (see FIG. 6)
Consisting of the following composition on a black PET film (Lumirror X30 (75 μm); manufactured by Toray Industries, Inc.) (adhesive layer solution)
・ Acrylic adhesive (Nissetsu PE-118; manufactured by Nippon Carbide Industries Co., Ltd.) 100 parts by weight ・ Isocyanate-based crosslinking agent (Nissetsu CK-101; manufactured by Nippon Carbide Industries Co., Ltd.) 2 parts by weight ・ Solvent ( (Methyl ethyl ketone / toluene / ethyl acetate = 2/1/1 (weight ratio)) 60 parts by weight of the adhesive layer solution was applied with an applicator to a film thickness of 25 μm after drying and then dried in an oven at 100 ° C. Layer 1 / black PET film was obtained. After drying, separator 1 (SPPET (38 μm); manufactured by Tosero Co., Ltd.) was laminated on one surface of the adhesive layer to obtain separator 1 / adhesive layer 1 / black PET film. Thereafter, an adhesive layer 2 (the same solution as the adhesive layer 1 is used) is formed on the other surface of the black PET film using the same method, and a separator 2 (SPPET (38 μm); manufactured by Tosero Co., Ltd.) Were laminated to obtain a laminate 3.
(4) Cholesteric liquid crystal medium 1 with volume hologram (production of cholesteric liquid crystal layer / volume hologram layer / adhesive layer 1 / black PET film / adhesive layer 2 / separator 2) (see FIG. 7)
The untreated PET film 2 of the laminate 2 (cholesteric liquid crystal layer / volume hologram layer / untreated PET film 2) and the laminate 3 (separator 1 / adhesive layer 1 / black PET film / adhesive layer 2 / separator 2) The separator 1 was peeled off, and the volume hologram layer surface of the laminate 2 and the adhesive layer 1 surface were laminated to face each other to obtain a cholesteric liquid crystal medium 1 with a volume hologram.
(Example 1 ')
(1) Production of laminate 1 ′ (untreated PET film 1 / volume hologram layer / adhesive PET film) (see FIG. 8)
A laminate 1 ′ was obtained in the same manner except that an easy-adhesive PET film (Cosmo Shine A4100 (50 μm); manufactured by Toyobo) was used instead of the untreated PET film 2 in the production of the laminate 1.
(2) Production of laminate 2 ′ (cholesteric liquid crystal layer / volume hologram layer / adhesive PET film) (see FIG. 9)
A laminate 2 ′ was obtained by processing in the same manner except that the laminate 4 was used instead of the laminate 1 in the production of the laminate 2.
(3) Preparation of cholesteric liquid crystal medium 1 ′ with volume hologram (preparation of cholesteric liquid crystal layer / volume hologram layer easy-adhesion PET film / adhesion layer 1 / black PET film / adhesion layer 2 / separator 2) (see FIG. 10)
Volume type hologram by peeling separator 1 of laminate 3 (separator 1 / adhesive layer 1 / black PET film / adhesive layer 2 / separator 2) and laminating the adhesive layer 1 side and the easy-adhesive PET film side of laminate 5 A cholesteric liquid crystal medium 1 ′ was obtained.
(Example 2)
(1) Production of laminate 4 (untreated PET film 3 / peelable protective layer / heat seal layer) (see FIG. 11)
The following composition (peelable protective layer solution) on untreated PET film 3 (Lumirror T60 (25 μm); manufactured by Toray Industries, Inc.)
-Polymethyl methacrylate (weight average molecular weight 100,000) 97 parts by weight-Polyethylene wax (weight average molecular weight 10,000) 3 parts by weight-Solvent (methyl ethyl ketone / toluene = 1/1 (weight ratio)) 400 parts by weight After applying the protective layer solution to a film thickness of 1 μm after drying with a bar coater, it is dried in an oven, and the following composition (heat seal layer solution) is formed thereon.
-Polyester resin (Vylonal MD1985; manufactured by Toyobo Co., Ltd.) 100 parts by weight-Solvent (water / isopropyl alcohol = 1/1 (weight ratio)) After drying a heat seal layer solution consisting of 100 parts by weight with a bar coater After coating to a thickness of 4 μm, the laminate 4 was obtained by drying in an oven.
(2) Production of laminate 5 (untreated PET film 3 / peelable protective layer / heat seal layer / cholesteric liquid crystal layer / volume hologram layer / untreated PET film 2) (see FIG. 12)
The laminated body 5 was obtained by facing the cholesteric liquid crystal surface of the laminated body 2 so as to face the heat seal layer surface of the laminated body 4 and passing through a roller at 130 ° C. to perform thermal lamination.
(3) Cholesteric liquid crystal medium 2 with volume hologram (untreated PET film 3 / peelable protective layer / heat seal layer / cholesteric liquid crystal layer / volume hologram layer / heat seal layer) (see FIG. 13)
The untreated PET film 2 of the laminate 5 is peeled off, and the heat seal layer solution used in the laminate 4 is applied to the surface of the volume hologram layer so as to have a film thickness of 4 μm after drying with a bar coater, and then dried in an oven. A cholesteric liquid crystal medium 2 with a hologram was obtained.

It is a figure which shows the cross section at the time of manufacture of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross section at the time of manufacture of the cholesteric liquid crystal medium with a volume type hologram of this invention. The cross-sectional structure of a cholesteric liquid crystal medium with a volume hologram after label processing or transfer foil processing is shown. It is a figure which shows the cross-section in the manufacturing process of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross-section in the manufacturing process of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross-section in the manufacturing process of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross-section of the cholesteric liquid crystal medium with a volume type hologram manufactured by the method of this invention. It is a figure which shows the cross-section in the manufacturing process of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross-section in the manufacturing process of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross-section of the cholesteric liquid crystal medium with a volume type hologram manufactured by the method of this invention. It is a figure which shows the cross-section in the manufacturing process of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross-section in the manufacturing process of the cholesteric liquid crystal medium with a volume type hologram of this invention. It is a figure which shows the cross-section of the cholesteric liquid crystal medium with a volume type hologram manufactured by the method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Volume type hologram layer, 3 ... Cholesteric liquid crystal layer, 4 ... Adhesive layer (or heat seal layer), 5 ... Base material

Claims (4)

A method for producing a cholesteric liquid crystal medium with a volume hologram having a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer,
Forming a volume hologram layer on the first substrate;
Forming a cholesteric liquid crystal layer on the volume hologram layer;
Peeling the first substrate;
Forming an adhesive layer on the surface of the volume hologram layer from which the first substrate has been peeled;
And a step of providing a second substrate on the adhesive layer. A method for producing a cholesteric liquid crystal medium with a volume hologram. A method for producing a cholesteric liquid crystal medium with a volume hologram having a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer,
Forming a volume hologram layer on the first substrate;
Forming a cholesteric liquid crystal layer on the volume hologram layer;
Forming a pressure-sensitive adhesive layer on the surface of the first base material on which the volume hologram layer is not formed. A method for producing a cholesteric liquid crystal medium with a volume hologram. A method for producing a cholesteric liquid crystal medium with a volume hologram having a two-layer structure of a volume hologram layer and a cholesteric liquid crystal layer,
Forming a volume hologram layer on the first substrate;
Forming a cholesteric liquid crystal layer on the volume hologram layer;
Peeling the first substrate;
And a step of forming a heat seal layer on the surface of the volume hologram layer from which the first base material has been peeled. A method for producing a cholesteric liquid crystal medium with a volume hologram. The method for producing a cholesteric liquid crystal medium with a volume hologram according to claim 3, further comprising the step of providing a second base material on the heat seal layer.

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