Genuine / Fake Determination Member and Method for Determining Its Authenticity

Abstract

The authenticity determination member includes: a base material layer, which is a reflective circular polarizer; a first printed layer provided on the base material layer, comprising a resin pigment that is a fragment from a resin layer A1 having cholesteric regularity; and a second printed layer provided on the base material layer, comprising a metal pigment having no circularly polarized light separation function. The authenticity determination method for the authenticity determination member comprises: the step (1) of injecting a nonpolarized light from one main surface of the authenticity determination member, to perform an observation and obtain a reflected image (1); the step (2) of injecting a nonpolarized light from the other main surface of the authenticity determination member, to perform an observation and obtain a reflected image (2); and the step (3) of determining that the reflected image (1) and the reflected image (2) are different.

Description

Technical Field

[0001] The present invention relates to a authenticity determination member and a method for determining its authenticity.

Background Art

[0002] In order to prevent the forgery of valuable articles, a medium in which different images are visible when observed from the front and when observed from the back is known. Patent Document 1 discloses a medium obtained by forming printed images on the front side of a base material having a function of transmitting one of left and right circularly polarized lights, using a cholesteric liquid crystal material having a property of reflecting circularly polarized light rotating in the opposite direction to one of the circularly polarized lights that can pass through the base material, and a material not having such a property, respectively.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique of Patent Document 1, when a printing layer is formed of a material containing a metal pigment as a material not having a property of reflecting circularly polarized light rotating in the opposite direction to one of the circularly polarized lights that can pass through the base material, the degree of freedom of expression by the printing layer may decrease. This is because when the printing layer is observed from the back side of the medium (that is, the side of the base material opposite to the surface on which the printing layer is provided), instead of observing a reflected image of the metallic color by the printing layer, it is simply observed as a black image. When the degree of freedom of expression decreases, it may become difficult to determine the authenticity of the medium.

[0005] Therefore, there is a need for an authenticity determination member including a printing layer containing a metal pigment, which can obtain different reflected images when observed from the front and when observed from the back; and a method for determining the authenticity of the authenticity determination member.

Means for Solving the Problems

[0006] As a result of intensive studies to solve the above problems, the present inventors have found that the problem can be solved by providing, on a base material layer, a first printing layer containing a resin pigment that is a fragment of a resin layer having a cholesteric regularity and is a reflective circular polarizer, and a second printing layer containing a metal pigment, and have completed the present invention. That is, the present invention provides the following.

[0007] [1] A counterfeit determination member including a base material layer that is a reflective circular polarizer, a first printing layer that contains a resin pigment that is a fragment of a resin layer A1 having a cholesteric regularity and is provided on the base material layer, and a second printing layer that contains a metal pigment having no circular polarization separation function and is provided on the base material layer. A first printing layer that contains a resin pigment that is a fragment of a resin layer A1 having a cholesteric regularity and is provided on the base material layer, and A second printing layer that contains a metal pigment having no circular polarization separation function and is provided on the base material layer. [2] The counterfeit determination member according to [1], wherein a reflection image (1) observed by making non-polarized light incident from one main surface side of the counterfeit determination member and a reflection image (2) observed by making non-polarized light incident from the other main surface side of the counterfeit determination member are different. [3] The counterfeit determination member according to [1] or [2], wherein the resin layer A1 has a reflectance of 40% or more at at least one wavelength in the visible wavelength band, and a half-value width of a reflection band having a reflectance of 35% or more and 50% or less is 350 nm or more. [4] The counterfeit determination member according to any one of [1] to [3], wherein the base material layer is a resin layer A2 having a cholesteric regularity, and the resin layer A1 and the resin layer A2 have a cholesteric regularity in the same twist direction. [5] The counterfeit determination member according to [4], wherein the resin layer A2 has a reflectance of 40% or more at at least one wavelength in the visible wavelength band, and a half-value width of a reflection band having a reflectance of 35% or more and 50% or less is 350 nm or more. [6] The counterfeit determination member according to [1] or [2], wherein the base material layer is a reflective circular polarizer including a reflective linear polarizer, a first λ / 4 plate provided on one main surface of the reflective linear polarizer, and a second λ / 4 plate provided on the other main surface of the reflective linear polarizer. [7] From one main surface side of the authenticity determination member according to any one of [1] to [6], non-polarized light is incident and observed to obtain a reflected image (1) in step (1), From the other main surface side of the authenticity determination member, non-polarized light is incident and observed to obtain a reflected image (2) in step (2), and An authenticity determination method for an authenticity determination member, including step (3) of determining that the reflected image (1) and the reflected image (2) are different.

Effect of the Invention

[0008] According to the present invention, an authenticity determination member including a printed layer containing a metallic pigment, capable of obtaining different reflected images when observed from the front and when observed from the back; and an authenticity determination method for the authenticity determination member; can be provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and the equivalent scope thereof.

[0011] In a plurality of drawings, elements commonly illustrated may be denoted by the same reference numerals, and the description thereof may be omitted.

[0012] In the following description, unless otherwise specified, the slow axis of a film or layer represents the slow axis in the plane of the film or layer.

[0013] In the following description, the term “(meth)acryloyl” includes “acryloyl”, “methacryloyl” and combinations thereof.

[0014] In the following description, unless otherwise specified, the directions of elements such as “parallel”, “perpendicular” and “orthogonal” may include errors within a range that does not impair the effects of the present invention, for example, within a range of ±3°, ±2° or ±1°.

[0015] In the following description, circular polarization includes elliptical polarization.

[0016] In the following description, the visible wavelength band means the wavelength range of visible light, which means a range of 380 nm or more and 830 nm or less.

[0017] In the following description, unless otherwise specified, the “quarter-wave plate” includes not only a rigid member but also a flexible member such as a resin film.

[0018] [1. Genuine / Fake Discriminating Member] The genuine / fake discriminating member according to an embodiment of the present invention includes a base material layer, a first printing layer provided on the base material layer, and a second printing layer provided on the base material layer. The base material layer is a reflective circular polarizer. The first printing layer contains a resin pigment that is a fragment of a resin layer A1 having cholesteric regularity. The second printing layer contains a metal pigment that does not have a circular polarization separation function.

[0019] [1.1. Base Material Layer] The base material layer is a reflective circular polarizer. A reflective circular polarizer means a polarizer having a function of reflecting circularly polarized light having one rotational direction and transmitting circularly polarized light having the other rotational direction among circularly polarized light having a clockwise rotational direction and circularly polarized light having a counterclockwise rotational direction. Such a function is also referred to as a circular polarization separation function. The reflective circular polarizer may be a multilayer body including a base material film or the like. Examples of such a reflective circular polarizer include (1) a resin layer having cholesteric regularity, and (2) a multilayer body including a reflective linear polarizer, a first λ / 4 plate provided on one main surface of the reflective linear polarizer, and a second λ / 4 plate provided on the other main surface of the reflective linear polarizer (a multilayer body in which λ / 4 plates are provided on both surfaces of the reflective linear polarizer). As the base material layer, a layer including a resin layer having cholesteric regularity is preferable, and it is more preferable that the base material layer is a resin layer having cholesteric regularity.

[0020] Here, the cholesteric regularity means that on one plane, the molecular axes are aligned in a certain direction, but in the next plane that overlaps it, the direction of the molecular axes is shifted by a certain angle, and in the next plane, the angle is further shifted. That is, as it progresses through the planes that are arranged in an overlapping manner, the angle of the molecular axes in the plane is shifted (twisted). Namely, when the molecules within the layer have cholesteric regularity, the molecules are aligned in a manner that forms multiple molecular layers within the resin layer. In a certain layer A among such multiple molecular layers, the molecules are aligned such that the axes of the molecules are in a certain direction, and in the adjacent layer B, the molecules are aligned in a direction shifted at an angle with respect to the direction in layer A, and in the layer C that is further adjacent to it, the molecules are aligned in a direction further shifted at an angle with respect to the direction in layer B. Thus, in multiple molecular layers, a structure is formed in which the angle of the molecular axes is continuously shifted and the molecules are twisted. Such a structure in which the direction of the molecular axes is twisted becomes an optically chiral structure.

[0021] Hereinafter, the resin layer having cholesteric regularity that can constitute the base material layer is also referred to as a cholesteric resin layer or resin layer A2. The reflection in the cholesteric resin layer reflects circularly polarized light while maintaining its chirality.

[0022] The cholesteric resin layer preferably has a reflectance of 40% or more at at least one wavelength in the visible wavelength band. Thereby, the reflected image observed by irradiating the authenticity determination member with unpolarized light becomes clear, and it becomes easy to determine the authenticity of the authenticity determination member. The reflectance of the cholesteric resin layer is usually 50% or less. In addition, it is preferable that the cholesteric resin layer has a half-value width of the reflection band with a reflectance of 35% or more and 50% or less of 350 nm or more. By the cholesteric resin layer exhibiting a circular polarization separation function in a wide wavelength range, the authenticity determination of the genuine / fake determination member can be performed at wavelengths in a wide range. Further, the reflected light of the cholesteric resin layer can be made a color close to metallic white (silver color), and the degree of freedom in design can be increased. The upper limit of the half-value width is not particularly limited and can be a width over the entire visible light band. For example, it can be 500 nm or less, or 400 nm or less.

[0023] The wavelength at which the circular polarization separation function is exhibited generally depends on the pitch of the helical structure in the cholesteric resin layer. The pitch of the helical structure is the distance in the direction of the plane normal until the direction of the molecular axis in the helical structure gradually shifts in angle continuously as it progresses in the plane and then returns to the original molecular axis direction again. By changing the magnitude of the pitch of this helical structure, the wavelength at which the circular polarization separation function is exhibited can be changed. Examples of cholesteric resin layers that can exhibit a circular polarization separation function in a wide wavelength range, such as the cholesteric resin layer with a half-value width of the reflection band of 350 nm or more, include (i) a cholesteric resin layer in which the magnitude of the pitch of the helical structure is changed stepwise, (ii) a cholesteric resin layer in which the magnitude of the pitch of the helical structure is changed continuously, and the like.

[0024] The cholesteric resin layer can be obtained, for example, by providing a film of a cholesteric liquid crystal composition on a suitable support for forming a resin layer and curing the film of the cholesteric liquid crystal composition. The obtained layer can be used as the cholesteric resin layer as it is.

[0025] As the cholesteric liquid crystal composition for forming a cholesteric resin layer, for example, a composition containing a liquid crystalline compound and capable of exhibiting a cholesteric liquid crystal phase when forming a film on a support can be used. Here, as the liquid crystalline compound, a liquid crystalline compound which is a polymer compound and a polymerizable liquid crystalline compound can be used. The cholesteric liquid crystal composition may contain one kind of liquid crystalline compound alone, or may contain two or more kinds in any combination.

[0026] In order to obtain high thermal stability, it is preferable to use a polymerizable liquid crystalline compound. By polymerizing such a polymerizable liquid crystalline compound in a state exhibiting cholesteric regularity, the film of the cholesteric liquid crystal composition can be cured to obtain a non-liquid crystalline resin layer cured while exhibiting cholesteric regularity.

[0027] Examples of the polymerizable liquid crystalline compound include rod-like liquid crystalline compounds represented by the following general formula (1). R 1 -C 1 -D 1 -C 3 -M-C 4 -D 2 -C 2 -R 2 (1)

[0028] In general formula (1), R 1 and R 2 each independently represent a polymerizable functional group. Examples of the polymerizable functional group include a carboxyl group, a (meth)acryloyl group, an epoxy group, a thioepoxy group, a mercapto group, an isocyanate group, an isothiocyanate group, an oxetane group, a thietanyl group, an aziridinyl group, a pyrrole group, a vinyl group, an allyl group, a fumarate group, a cinnamoyl group, an oxazoline group, a hydroxyl group, an alkoxysilyl group, and an amino group, etc.

[0029] In general formula (1), D 1 and D 2Each independently represents a group selected from the group consisting of a single bond, a divalent saturated hydrocarbon group such as a linear or branched methylene group and alkylene group having 1 to 20 carbon atoms, and a linear or branched alkylene oxide group having 1 to 20 carbon atoms.

[0030] In General Formula (1), C 1 ~C 4 Each independently represents a group selected from the group consisting of a single bond, -O-, -S-, -S-S-, -CO-, -CS-, -OCO-, -CH2-, -OCH2-, -CH=N-N=CH-, -NHCO-, -OCOO-, -CH2COO-, and -CH2OCO-.

[0031] In General Formula (1), M represents a mesogenic group. Specific examples of M include 2 to 4 skeletons selected from the group consisting of azomethines, azoxy compounds, phenyls, biphenyls, terphenyls, naphthalenes, anthracenes, benzoic acid esters, phenyl cyclohexanecarboxylates, cyanophenyl cyclohexanes, cyanophenyl pyrimidines, alkoxy-substituted phenyl pyrimidines, phenyl dioxanes, trans compounds, alkenyl cyclohexyl benzonitriles, which may be unsubstituted or have substituents, and are formed by being bonded by a bonding group such as -O-, -S-, -S-S-, -CO-, -CS-, -OCO-, -CH2-, -OCH2-, -CH=N-N=CH-, -NHCO-, -OCOO-, -CH2COO-, and -CH2OCO-.

[0032] Examples of the substituents that the mesogenic group M may have include, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms that may have a substituent, a cyano group, a nitro group, -O-R 3 -O-C(=O)-R 3 -C(=O)-O-R 3 -O-C(=O)-O-R 3 -NR 3 -C(=O)-R 3 -C(=O)-NR 3 R 4 or -O-C(=O)-NR 3R 4 [Represents.] Here, R 3 and R 4 represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. When R 3 and R 4 are alkyl groups, the alkyl group may have -O-, -S-, -O-C(=O)-, -C(=O)-O-, -O-C(=O)-O-, -NR 5 -C(=O)-, -C(=O)-NR 5 -, -NR 5 -, or -C(=O)- intervening (except when -O- and -S- intervene adjacently two or more times). Here, R 5 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the substituent in the "alkyl group having 1 to 10 carbon atoms which may have a substituent" include a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkoxy group having 2 to 8 carbon atoms, an alkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylcarbonyloxy group having 2 to 7 carbon atoms, an alkoxycarbonyloxy group having 2 to 7 carbon atoms, etc.

[0033] Preferred specific examples of the rod-like liquid crystalline compound include the following compounds (B1) to (B10). Also, these may be used alone or in combination of two or more in any ratio.

[0034]

Chemical formula

[0035] The concentration of the liquid crystalline compound in the cholesteric liquid crystal composition is not particularly limited, but is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 14% by weight or more, particularly preferably 15% by weight or more, preferably 40% by weight or less, more preferably 35% by weight or less, still more preferably 30% by weight or less. ​

[0036] The cholesteric liquid crystal composition may contain an alignment aid for assisting the alignment of liquid crystalline compounds. The alignment aid may be a substance having no liquid crystallinity.

[0037] Examples of the alignment aid include compounds represented by the following general formula (2). R 6 -A 1 -Z-A 2 -R 7 (2)

[0038] In general formula (2), R 6 and R 7 each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkylene oxide group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a (meth)acryloyl group which may have an arbitrary linking group intervening therebetween, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group.

[0039] The alkyl group and the alkylene oxide group may not be substituted, or may be substituted with one or more halogen atoms. Further, when two or more substituents are present in each of the alkyl group and the alkylene oxide group, they may be the same or different. Further, the halogen atom, the hydroxyl group, the carboxyl group, the (meth)acryloyl group, the epoxy group, the mercapto group, the isocyanate group, the amino group, and the cyano group may be bonded to an alkyl group and / or an alkylene oxide group having 1 to 2 carbon atoms.

[0040] R 6 and R 7 Preferred examples as R

[0041] R 6and R 7 It is preferable that at least one of them is a polymerizable functional group. R 6 and / or R 7 By having a polymerizable functional group as, the compound represented by the general formula (2) can be fixed in the liquid crystal layer during curing, and a liquid crystal cured product layer which is a stronger film can be formed. Here, examples of the polymerizable functional group include the same ones as those of the polymerizable liquid crystal compound, and among them, a carboxyl group, a (meth)acryloyl group, an epoxy group, a mercapto group, an isocyanate group, and an amino group are preferable.

[0042] In the general formula (2), A 1 and A 2 each independently represents a group selected from the group consisting of a 1,4-phenylene group, a 1,4-cyclohexylene group, a cyclohexene-1,4-diyl group, a 4,4'-biphenylene group, a 4,4'-bicyclohexylene group, and a 2,6-naphthylene group. The 1,4-phenylene group, 1,4-cyclohexylene group, cyclohexene-1,4-diyl group, 4,4'-biphenylene group, 4,4'-bicyclohexylene group, and 2,6-naphthylene group may not be substituted, or may be substituted with one or more substituents such as a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkyl group having 1 to 10 carbon atoms, and a halogenated alkyl group. Further, in each of A 1 and A 2 , when two or more substituents are present, they may be the same or different.

[0043] A 1 and A 2 Particularly preferable examples of A include a 1,4-phenylene group, a 4,4'-biphenylene group, and a 2,6-naphthylene group. These aromatic ring skeletons are relatively rigid compared to the alicyclic skeleton, have a high affinity with the mesogen of the polymerizable liquid crystal compound, and have a higher orientation uniformity ability.

[0044] In general formula (2), Z is selected from the group consisting of a single bond, -O-, -S-, -S-S-, -CO-, -CS-, -OCO-, -CH2-, -OCH2-, -CH=N-N=CH-, -NHCO-, -OCOO-, -CH2COO-, and -CH2OCO-. Particularly preferred examples of Z include a single bond, -OCO- and -CH=N-N=CH-.

[0045] Particularly preferred specific examples of the compound represented by general formula (2) include, for example, the following compounds (A1) to (A10). In compound (A3), "*" represents a chiral center.

[0046] [Chemical formula]

[0047] The cholesteric liquid crystal composition may contain a chiral agent, and it is preferably contained. Usually, the twist direction of the cholesteric resin layer can be appropriately selected according to the type and structure of the chiral agent used. When the twist is in the right direction, a chiral agent that imparts dextrorotation is used, and when the twist direction is in the left direction, it can be realized by using a chiral agent that imparts levorotation. Specific examples of the chiral agent can be appropriately used as those described in JP-A-2005-289881, JP-A-2004-115414, JP-A-2003-66214, JP-A-2003-313187, JP-A-2003-342219, JP-A-2000-290315, JP-A-6-072962, US Patent No. 6468444, WO98 / 00428, JP-A-2007-176870, etc., and can be obtained, for example, as LC756 of BASF's Paricolor. Further, the chiral agent may be used alone or in combination of two or more in any ratio.

[0048] The amount of the chiral agent can be arbitrarily set within a range that does not reduce the desired optical performance. The specific amount of the chiral agent is, for example, 1% by weight to 60% by weight in the cholesteric liquid crystal composition.

[0049] The cholesteric liquid crystal composition may contain a polymerization initiator. Examples of the polymerization initiator include a photopolymerization initiator. As the photopolymerization initiator, for example, known compounds that generate radicals or acids by ultraviolet rays or visible light can be used.

[0050] Specific examples of the photoinitiator include benzoin, benzyl dimethyl ketal, benzophenone, biacetyl, acetophenone, Michler's ketone, benzyl, benzyl isobutyl ether, tetramethylthiuram mono(di)sulfide, 2,2-azobisisobutyronitrile, 2,2-azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, di-tert-butyl peroxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, methyl benzoyl formate, 2,2-diethoxyacetophenone, β-ionone, β-bromostyrene, diazoaminobenzene, α-amyl cinnamic aldehyde, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, p,p'-dichlorobenzophenone, p,p'-bisdiethylaminobenzophenone, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-propyl ether, benzoin n-butyl ether, diphenyl sulfide, bis(2,6-methoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, anthracene benzophenone, α-chloroanthraquinone, diphenyl disulfide, hexachlorobutadiene, pentachlorobutadiene, octachlorobutene, 1-chloromethylnaphthalene, 1,2 - Octanedione - 1 - [4 - (phenylthio)phenyl - 2 - (o - benzoyloxime)], carbazole oxime compounds such as 1 - [9 - ethyl - 6 - (2 - methylbenzoyl) - 9H - carbazol - 3 - yl] ethanone 1 - (o - acetyloxime), (4 - methylphenyl)[4 - (2 - methylpropyl)phenyl] iodonium hexafluorophosphate, 3 - methyl - 2 - butynyltetramethylene sulfonium hexafluoroantimonate, diphenyl - (p - phenylthiophenyl) sulfonium hexafluoroantimonate, etc. can be mentioned., As commercially available products, for example, Irgacure OXE02 of BASF can be used., The polymerization initiator may be used alone or in combination of two or more kinds in any ratio.,

[0051] The cholesteric liquid crystal composition may contain a surfactant. As the surfactant, for example, those that do not inhibit alignment can be appropriately selected and used. As such a surfactant, for example, nonionic surfactants containing a siloxane or fluorinated alkyl group in the hydrophobic moiety are preferably mentioned. Among them, oligomers having two or more hydrophobic moiety in one molecule are particularly preferred. Specific examples of these surfactants include PF - 151N, PF - 636, PF - 6320, PF - 656, PF - 6520, PF - 3320, PF - 651, PF - 652 of PolyFox of OMNOVA; FTX - 209F, FTX - 208G, FTX - 204D of Furgent of Neos; KH - 40, S420 of Surfron of Seimi Chemical Co., Ltd.; etc. can be used., The surfactant may be used alone or in combination of two or more kinds in any ratio.,

[0052] The cholesteric liquid crystal composition may optionally contain a crosslinking agent in order to improve the film strength and durability after curing. As the crosslinking agent, those that can increase the crosslinking density of the cholesteric resin layer and do not deteriorate the alignment uniformity can be appropriately selected and used. The increase in such crosslinking density can be achieved by a reaction that occurs simultaneously with curing during the curing of the film of the liquid crystal composition, by promoting the reaction by performing heat treatment after curing, or by a reaction that naturally proceeds due to moisture. Therefore, for example, any crosslinking agent that cures with ultraviolet rays, heat, moisture, etc. can be preferably used.

[0053] Examples of the crosslinking agent include polyfunctional acrylate compounds; aziridine compounds; isocyanate compounds; polyoxazoline compounds having an oxazoline group in the side chain; alkoxysilane compounds. Further, the crosslinking agent may be used alone or in combination of two or more in any ratio.

[0054] The cholesteric liquid crystal composition may further contain other optional components as necessary. Examples of this optional component include solvents, polymerization inhibitors for improving pot life, antioxidants for improving durability, ultraviolet absorbers, and light stabilizers. Further, these optional components may be used alone or in combination of two or more in any ratio. The amounts of these optional components can be arbitrarily set within a range that does not deteriorate the desired optical performance.

[0055] The method for producing the cholesteric liquid crystal composition is not particularly limited and can be produced by mixing the above components.

[0056] After preparing the above-described photocurable cholesteric liquid crystal composition, a film of the liquid crystal composition is provided on a substrate film. Usually, a film of the liquid crystal composition is provided by applying the liquid crystal composition to the surface of the substrate film. Further, when the substrate film has an alignment film, usually, a film of the liquid crystal composition is provided on the alignment film. Furthermore, before applying the liquid crystal composition, the surface of the substrate film may be subjected to treatments such as corona discharge treatment and rubbing treatment as necessary.

[0057] After providing a film of a liquid crystal composition on a substrate film, an alignment treatment may be performed as necessary. The alignment treatment can be performed, for example, by heating the film of the liquid crystal composition at 50°C to 150°C for 0.5 minute to 10 minutes. By performing the alignment treatment, the liquid crystal composition in the film can be favorably aligned.

[0058] Thereafter, in order to cure the film of the liquid crystal composition, a curing treatment is usually performed. The curing treatment can be performed, for example, by a combination of one or more light irradiations and heating treatments. The heating conditions can be, for example, usually at a temperature of 40°C or higher, preferably 50°C or higher, and usually 200°C or lower, preferably 140°C or lower, and usually for a time of 1 second or longer, preferably 5 seconds or longer, and usually 3 minutes or shorter, preferably 120 seconds or shorter. Also, the light used for light irradiation includes not only visible light but also ultraviolet rays and other electromagnetic waves. The light irradiation can be performed, for example, by irradiating light having a wavelength of 200 nm to 500 nm for 0.01 second to 3 minutes. At this time, the energy of the irradiated light can be, for example, 0.01 mJ / cm 2 ~50 mJ / cm 2 and can be.

[0059] 0.01 mJ / cm 2 ~50 mJ / cm 2 By repeatedly alternating a plurality of times a weak ultraviolet irradiation of 0.01 mJ / cm 2 ~50 mJ / cm 2 and heating, a cholesteric resin layer having a circular polarization separation function with a wide reflection band, in which the pitch size of the helical structure is continuously and greatly changed, can be obtained. Further, after expanding the reflection band by the above-described weak ultraviolet irradiation or the like, a relatively strong ultraviolet ray such as 50 mJ / cm 2 ~10,000 mJ / cm 2 is irradiated to completely polymerize the liquid crystalline compound, whereby a cholesteric resin layer having high mechanical strength can be obtained. The above-described expansion of the reflection band and irradiation with strong ultraviolet rays may be performed under air, or a part or all of the process may be performed in an atmosphere in which the oxygen concentration is controlled (for example, under a nitrogen atmosphere).

[0060] The steps of applying and curing the liquid crystal composition as described above are not limited to once, and the application and curing may be repeated a plurality of times. Thereby, a cholesteric resin layer including two or more layers can be formed. However, by using the liquid crystal composition described in the above example, a cholesteric resin layer having a thickness of 5 μm or more and containing a rod-like liquid crystalline compound that is favorably oriented can be easily formed even by applying and curing the liquid crystal composition only once.

[0061] As the reflective circular polarizer, as described above, (2) a multilayer body including a reflective linear polarizer, a first λ / 4 plate, and a second λ / 4 plate can be used. Examples of the reflective linear polarizer included in such a multilayer body include a wire grid type linear polarizer and a multilayer reflective linear polarizer (for example, "DBEF" manufactured by 3M).

[0062] The thickness of the base material layer is not particularly limited, but is preferably 3.0 μm or more, more preferably 4.0 μm or more, particularly preferably 4.5 μm or more, preferably 20 μm or less, more preferably 15 μm or less, and particularly preferably 10 μm or less.

[0063] [1.2. First printing layer] The resin pigment contained in the first printing layer is composed of fragments of a resin layer having cholesteric regularity. The resin pigment can be produced by forming a resin layer having cholesteric regularity (hereinafter also referred to as resin layer A1), and crushing this layer into fragments.

[0064] The resin layer A1 can be obtained, for example, in the same manner as the resin layer A2 having cholesteric regularity as the base material layer, by providing a film of a cholesteric liquid crystal composition on a suitable support for forming a resin layer, and curing the film of the cholesteric liquid crystal composition. Examples of the cholesteric liquid crystal composition for forming a cholesteric resin layer include the same examples and preferred examples as the cholesteric liquid crystal composition for forming the resin layer A2.

[0065] The resin layer A1 preferably has a reflectance of 40% or more at at least one wavelength in the visible wavelength band. As a result, the reflected image observed by irradiating the authenticity determination member with unpolarized light becomes clear, and it becomes easy to determine the authenticity of the authenticity determination member. The reflectance of the resin layer A1 is usually 50% or less. Also, the resin layer A1 preferably has a half-value width of the reflection band with a reflectance of 35% or more and 50% or less of 350 nm or more. By the resin layer A1 exhibiting a circularly polarized light separating function in a wide wavelength range, the authenticity determination of the authenticity determination member can be performed at a wide range of wavelengths. Further, the reflected light from the first printing layer containing the resin pigment composed of fragments of the resin layer A1 can be made a color close to metallic white (silver), and the degree of freedom in design can be increased.

[0066] The thickness of the resin layer A1 is not particularly limited, but is preferably 3.0 μm or more, more preferably 4.0 μm or more, particularly preferably 4.5 μm or more, and is preferably 20 μm or less, more preferably 15 μm or less, particularly preferably 10 μm or less.

[0067] The resin layer A2 and the resin layer A1 may be the same layer formed from the same cholesteric liquid crystal composition by the same method, or may be different layers from each other.

[0068] The resin layer A2 and the resin layer A1 preferably have the same cholesteric regularity in the same twist direction. Making the cholesteric regularity in the resin layer A2 and the resin layer A1 in the same twist direction can be achieved, for example, by appropriately selecting the type and structure of the chiral agent used in the cholesteric liquid crystal composition for forming the resin layer A2 or the resin layer A1.

[0069] Examples of the method for producing the resin pigment from the resin layer A1 include: after forming the resin layer A1 on the base film, peeling the resin layer A1 from the base film to obtain a resin layer piece, and using the obtained resin layer piece as it is or further pulverizing it with a pulverizer or the like to obtain the resin pigment which is fragments of the resin layer A2. As a further specific example, the method described in JP-A-2015-027743 can be mentioned.

[0070] The dimensions of the fragments contained in the resin pigment can be arbitrarily set according to the printing method or the like for forming the first printing layer. However, when forming the first printing layer by the screen printing method, the resin pigment preferably has fragments that have passed through a sieve with an opening of 100 μm or less, and more preferably has fragments that have passed through a sieve with an opening of 60 μm or less. The resin pigment preferably has fragments that do not pass through a sieve with an opening of less than 5 μm.

[0071] The first printing layer is provided on the base material layer by an arbitrary method. The first printing layer is preferably provided on the base material layer by a printing method. In this specification, the "printing method" includes not only a method of transferring ink to the base material layer using a printing plate, but also a method of applying ink to the base material layer without using a printing plate, such as an inkjet printing method. Among them, the first printing layer is preferably provided on the base material layer by the screen printing method.

[0072] The first printing layer containing the resin pigment can be formed, for example, by transferring or applying an ink containing the resin pigment onto the base material layer.

[0073] The content of the resin pigment in the ink is not particularly limited, but can be, for example, 1% by weight or more, for example, 5% by weight or more, for example, 15% by weight or less, for example, 10% by weight or less.

[0074] The ink containing the resin pigment can contain arbitrary components in addition to the resin pigment. Examples of the arbitrary components contained in the ink include solvents (including dispersion media), binder resins, defoaming agents, stabilizers, waxes, surfactants, and the like. Examples of the binder resin include a thermosetting resin and a photocuring resin.

[0075] The thickness of the first printing layer is not particularly limited and can be arbitrarily set according to the printing method for forming the first printing layer or the like. For example, it can be 30 μm to 50 μm.

[0076] The first printing layer is preferably provided so as to be in contact with a part of one main surface of the base material layer and form a pattern when viewed from the thickness direction of the authenticity determination member. Examples of the pattern are not particularly limited, and include figures such as a square and a triangle, and characters.

[0077] [1.3. Second printing layer] The second printing layer contains a metal pigment that does not have a circular polarization separation function. Not having a circular polarization separation function means that both circular polarizations having one rotation direction and circular polarizations having the other rotation direction among circular polarizations are reflected with the same reflectance and transmitted with the same transmittance (the transmittance may be 0%). The metal pigment is usually a material having a metallic luster and includes a material that does not have a circular polarization separation function. Usually, since metal powder does not have a circular polarization separation function, it can be used as the metal pigment contained in the second printing layer. Also, metal oxides such as silica can be used as the material of the metal pigment.

[0078] Examples of the material of the metal pigment include aluminum, copper, silver, and silica. Powders and flakes of these materials can be used as the metal pigment. Also, flakes obtained by forming a film of a metal or a metal oxide such as silica on the surface of flakes made of a material other than metal, such as glass flakes, can be used as the metal pigment.

[0079] The dimensions of the metal pigment can be arbitrarily set according to the printing method for forming the second printing layer or the like. When the second printing layer is formed by the screen printing method, the metal pigment preferably has fragments that have passed through a sieve with an opening of 100 μm or less, and more preferably has fragments that have passed through a sieve with an opening of 60 μm or less. The metal pigment preferably has fragments that do not pass through a sieve with an opening of less than 5 μm.

[0080] The second printing layer is preferably provided on the base material layer by a printing method, and among them, it is preferably provided by a screen printing method.

[0081] The second printing layer containing a metal pigment can be formed, for example, by transferring or applying an ink containing a metal pigment on the base material layer. The ink containing a metal pigment may contain any component in addition to the metal pigment. Examples of any component contained in the ink include the same components as those that can be contained in the ink containing the resin pigment.

[0082] The thickness of the second printing layer is not particularly limited and can be arbitrarily set according to the printing method for forming the second printing layer, etc. For example, it can be 30 μm to 50 μm.

[0083] The second printing layer is preferably provided so as to be in contact with a part of one main surface of the base material layer and forms a pattern when viewed from the thickness direction of the authenticity determination member. Examples of the pattern are not particularly limited, and include figures such as squares and triangles, and characters. The first printing layer and the second printing layer may have the same pattern or different patterns.

[0084] The first printing layer and the second printing layer are preferably provided so as not to overlap when viewed from the thickness direction of the authenticity determination member. The second printing layer may be provided on the same main surface as the main surface of the base material layer on which the first printing layer is provided, or may be provided on a main surface different from the main surface of the base material layer on which the first printing layer is provided. In one embodiment, the second printing layer is provided on the same main surface as the main surface of the base material layer on which the first printing layer is provided.

[0085] [1.4. Function of the authenticity determination member] Hereinafter, the operation of the authenticity determination member according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view of the authenticity determination member according to an embodiment of the present invention as viewed from the thickness direction. FIG. 2 is a view schematically showing a cross-section taken along line II-II of FIG. 1. FIG. 3 is an explanatory view of the authenticity determination member according to an embodiment of the present invention when observed from one main surface side. FIG. 4 is an explanatory view of the authenticity determination member according to an embodiment of the present invention when observed from the other main surface side. FIG. 5 is a schematic view showing an image when the authenticity determination member according to an embodiment of the present invention is irradiated with non-polarized light and observed. FIG. 6 is a schematic view showing an image when the authenticity determination member according to an embodiment of the present invention in FIG. 5 is turned over and irradiated with non-polarized light and observed. FIG. 7 is a schematic plan view of the authenticity determination member according to the comparative example as viewed from the thickness direction. FIG. 8 is a view schematically showing a cross-section taken along line VIII-VIII of FIG. 7. FIG. 9 is an explanatory view of the authenticity determination member according to the comparative example when observed from one main surface side. FIG. 10 is an explanatory view of the authenticity determination member according to the comparative example when observed from the other main surface side.

[0086] As shown in FIG. 1, the authenticity determination member 100 according to an embodiment of the present invention includes a base material layer 10, a first printing layer 20, and a second printing layer 30. The base material layer 10 is a resin layer having a cholesteric regularity and having a function as a reflective circular polarizer that transmits left circularly polarized light and reflects right circularly polarized light. The first printing layer 20 includes fragments of a resin layer having the same twist direction cholesteric regularity as the base material layer 10. The first printing layer 20 has a circular polarization separation function of transmitting left circularly polarized light and reflecting right circularly polarized light, similar to the base material layer 10. The second printing layer 30 includes a metal pigment that does not have a circular polarization separation function. The first printing layer 20 and the second printing layer 30 form a pattern when viewed from the thickness direction (the direction perpendicular to the paper surface) of the authenticity determination member 100. In the present embodiment, the first printing layer 20 and the second printing layer 30 form a pattern of the number "8". As shown in FIG. 2, the first printing layer 20 and the second printing layer 30 are directly provided on one of the main surfaces 10U and 10D, which are the two main surfaces of the base material layer 10. The first printing layer 20 and the second printing layer 30 are arranged on the main surface 10U so as not to overlap each other.

[0087] The appearance of the image when non-polarized light is incident from the main surface 10U side of the genuine / fake determination member 100 and the genuine / fake determination member 100 is observed from the main surface 10U side will be described with reference to FIG. 3. As shown in FIG. 3, when light L1 which is non-polarized light is incident on the first printing layer 20 from the side of the main surface 10U, since the first printing layer 20 has the above-described circular polarization separation function, light L2 which is left circularly polarized light RL is transmitted, and light L4 which is right circularly polarized light L is reflected. As a result, the reflected light by the first printing layer 20 is visually recognized. Light L2 R passes through the base material layer 10 and becomes light L3 L . L

[0088] When light L5 which is non-polarized light is incident on the second printing layer 30 from the main surface 10U side, light L5 RL is reflected by the metal pigment contained in the second printing layer 30. As a result, light L6 which is non-polarized light RL is visually recognized as the reflected light by the second printing layer 30. RL Since the reflected light by the first printing layer 20 and the second printing layer 30 is visually recognized, as shown in FIG. 5, the number "8" is visually recognized as the reflected image (1).

[0089] Next, the appearance of the image when non-polarized light is incident from the main surface 10D side of the genuine / fake determination member 100 and the genuine / fake determination member 100 is observed from the main surface 10D side will be described with reference to FIG. 4. As shown in FIG. 4, when light L26 which is non-polarized light is incident from the main surface 10D side, since the base material layer 10 has the function of transmitting left circularly polarized light and reflecting right circularly polarized light, light L27 which is left circularly polarized light RL is transmitted, but right circularly polarized light is not transmitted and does not reach the first printing layer 20. Since the first printing layer 20 has the above-described circular polarization separation function, the reflected light by the first printing layer 20 is not visually recognized. Light L27 which is left circularly polarized light irradiated on the first printing layer 20 L passes through the first printing layer 20 and becomes light L28 L . L

[0090] ​​​ When non-polarized light L20 is incident on the second printing layer 30 from the main surface 10D side, RL the substrate layer 10 transmits light L21 which is left-circularly polarized light. L The transmitted light L21 L is reflected by the metal pigment contained in the second printing layer 30. At this time, due to metal reflection, the rotation direction of the circular polarization becomes reverse, so the reflected light by the second printing layer 30 is light L22 which is right-circularly polarized light. R Light L22 R is reflected by the substrate layer 10, and light L23 which is right-circularly polarized light is incident on the second printing layer 30. R Light L23 R is reflected by the second printing layer 30, and the rotation direction of the circular polarization becomes reverse, becoming light L24 which is left-circularly polarized light. L The light L24 reflected by the second printing layer 30 L is left-circularly polarized light, so it passes through the substrate layer 10 and becomes light L25 which is left-circularly polarized light. L That is, the reflected light by the second printing layer 30 is visually recognized as light L25. L

[0091] As described above, the reflected light by the first printing layer 20 is not visually recognized, and the reflected light by the second printing layer 30 is visually recognized. FIG. 6 is a diagram for explaining how the image looks when the authenticity determination member 100 in FIG. 5 is turned over with the axis R1 shown in FIG. 5 as the rotation axis and irradiated with non-polarized light for observation. As shown in FIG. 6, since the reflected light by the first printing layer 20 is not visually recognized and the reflected light by the second printing layer 30 is visually recognized, the number "5" is visually recognized as the reflected image (2).

[0092] As described above, the authenticity determination member 100 has different reflected images (1) obtained by observing with non-polarized light incident from one main surface 10U side and reflected images (2) obtained by observing with non-polarized light incident from the other main surface 10D side. Therefore, the fact that the reflected image (1) and the reflected image (2) are different can be set as one of the determination conditions for the authenticity of the authenticity determination member 100.

[0093] ​In this embodiment, the base material layer 10, which is a reflective circular polarizer, is a resin layer having cholesteric regularity. However, in another embodiment, the base material layer may be a reflective circular polarizer including a reflective linear polarizer, a first λ / 4 plate provided on one main surface of the reflective linear polarizer, and a second λ / 4 plate provided on the other main surface of the reflective linear polarizer.

[0094] Next, in order to compare with the operation of the authenticity determination member according to the present invention, the operation of the authenticity determination member when the base material layer is an absorptive circular polarizer instead of a reflective circular polarizer will be described. As shown in FIG. 7, the authenticity determination member 500 includes a base material layer 510, a first printing layer 520, and a second printing layer 530. The base material layer 510 has a function as an absorptive circular polarizer that transmits left circularly polarized light and absorbs right circularly polarized light. The first printing layer 520 has a circular polarization separation function that transmits left circularly polarized light and reflects right circularly polarized light. The second printing layer 530 contains a metal pigment that does not have a circular polarization separation function. The first printing layer 520 and the second printing layer 530 form a pattern when viewed from the thickness direction (direction perpendicular to the paper surface) of the authenticity determination member 500. In this example, similar to the authenticity determination member 100, the first printing layer 520 and the second printing layer 530 form a pattern of the number "8". As shown in FIG. 8, the base material layer 510 is formed by laminating a retardation layer 512 having a function as a λ / 4 plate, a linear polarizer 511, and a retardation layer 513 having a function as a λ / 4 plate in this order. The slow axis of the retardation layer 512, the absorption axis of the linear polarizer 511, and the slow axis of the retardation layer 513 form an angle such that the transmitted light of the base material layer 510 becomes left circularly polarized light. As shown in FIG. 8, the first printing layer 520 and the second printing layer 530 are directly provided on one of the main surfaces 510U and 510D, which are the two main surfaces of the base material layer 10. The first printing layer 520 and the second printing layer 530 are arranged on the main surface 510U so as not to overlap each other.

[0095] From the main surface 510U side of the genuine / fake determination member 500, the appearance of the image when non-polarized light is incident and the genuine / fake determination member 500 is observed from the main surface 510U side will be described with reference to FIG. 9. As shown in FIG. 9, when light L30 which is non-polarized light RL is incident on the first printing layer 520, light L31 which is left-circularly polarized light L is transmitted, and light L35 which is right-circularly polarized light R is reflected. As a result, the reflected light by the first printing layer 520 is visually recognized. Light L31 L passes through the retardation layer 512 and becomes light L32 which is linearly polarized light ST and passes through the linear polarizer 511. The transmitted linearly polarized light L33 ST passes through the retardation layer 513 and becomes light L34 which is left-circularly polarized light L . When non-polarized light L36 RL is incident on the second printing layer 530, light L36 RL is reflected by the metal pigment contained in the second printing layer 530. As a result, non-polarized light L37 RL is visually recognized as the reflected light by the second printing layer 530. Since the reflected light by the first printing layer 520 and the second printing layer 530 is visually recognized, the number "8" is visually recognized as a reflected image.

[0096] Next, the appearance of the image when non-polarized light is incident from the main surface 510D side of the genuine / fake determination member 500 and the genuine / fake determination member 500 is observed from the main surface 510D side will be described with reference to FIG. 10. As shown in FIG. 10, when light L46 which is non-polarized light RL is incident, light L46 RL passes through the retardation layer 513. Among the transmitted non-polarized light L47 RL , the linearly polarized light having the vibration direction parallel to the absorption axis of the linear polarizer 511 is absorbed, and only light L48 ST which is linearly polarized light having the vibration direction perpendicular to the absorption axis is transmitted. The transmitted light L48 ST passes through the retardation layer 512 and becomes light L49 which is left-circularly polarized light L . Light L49 Lenters the first printing layer 520, but since it is left circularly polarized light, it is not reflected by the first printing layer 520. Therefore, the reflected light by the first printing layer 520 is not visually recognized. Light L49 L passes through the first printing layer 520 and becomes light L50 L .

[0097] The non-polarized light L40 incident from the side of the main surface 510D RL passes through the retardation layer 513 and becomes non-polarized light L41 RL . Among the light L41 RL , a part of the light passes through the linear polarizer 511 and becomes linearly polarized light L42 ST . The light L42 ST becomes left circularly polarized light L43 by passing through the retardation layer 512 L . The light L43 L is reflected by the metal pigment contained in the second printing layer 530, and the rotation direction of the circular polarization becomes reverse, becoming right circularly polarized light L44 R . The light L44 R becomes linearly polarized light L45 by passing through the retardation layer 512 ST . Due to the reflection by the second printing layer 530, the rotation direction of the reflected light L44 is reversed with respect to the incident light L43 L . As a result, the light L45 R is linearly polarized light having a vibration direction parallel to the absorption axis of the linear polarizer 511. Therefore, it is absorbed by the linear polarizer 511. Therefore, the reflected light of the second printing layer 530 is not visually recognized. ST Therefore, unlike the forgery determination member 100, when observed from the side of the main surface 510D, not only the reflected light by the first printing layer 520 but also the reflected light by the second printing layer 530 is not visually recognized.

[0098] On the other hand, the forgery determination member 100 which is an embodiment of the present invention can visually recognize the reflected light by the second printing layer 30 as a metallic color whether observed from one main surface 10U or the other main surface 10D. Utilizing this action, the forgery determination member 100 can express various patterns on both the front and back surfaces. ​

[0099] [1.5. Use of the Genuine / Fake Determination Member] The genuine / fake determination member is suitably used to determine the authenticity of an article to be identified by taking advantage of the fact that the reflected images displayed on the front and back are different. Examples of articles to be determined for authenticity include articles such as money vouchers, commodity vouchers, tickets, certificates, security cards, etc. The genuine / fake determination member may be these articles themselves. The genuine / fake determination member can also be used in the form of a label for authenticity determination, etc.

[0100] [2. Method for Determining the Authenticity of the Genuine / Fake Determination Member] The genuine / fake determination member according to an embodiment of the present invention can determine authenticity by utilizing the above action. The determination method of the genuine / fake determination member according to an embodiment of the present invention includes a step (1) of making non-polarized light incident from one main surface side of the genuine / fake determination member and observing to obtain a reflected image (1), a step (2) of making non-polarized light incident from the other main surface side of the genuine / fake determination member and observing to obtain a reflected image (2), and a step (3) of determining that the reflected image (1) and the reflected image (2) are different. Step (1) and step (2) are not usually performed simultaneously. After step (1) and step (2), step (3) is performed.

[0101] "Different" means that when comparing the reflected image (1) and the reflected image (2), a part that does not exist in one image appears in the other image, and usually does not include the case where the reflected image (1) and the reflected image (2) are in a mirror image relationship.

Example

[0102] Hereinafter, the present invention will be specifically described by showing examples. However, the present invention is not limited to the examples shown below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

[0103] In the following description, “%” and “parts” representing amounts are on a weight basis unless otherwise specified. Also, the operations described below were carried out under conditions of normal temperature and normal pressure unless otherwise specified.

[0104] [Example 1] (1-1. Preparation of Cholesteric Liquid Crystal Composition) A cholesteric liquid crystal composition (20 wt% solids) for forming a cholesteric resin layer was prepared by mixing a polymerizable liquid crystal compound “Paliocolor LC242” manufactured by BASF, a chiral agent “Paliocolor LC756” manufactured by BASF, a photoinitiator “Irgacure OXE02” manufactured by BASF, a leveling agent “Surflon S420” manufactured by AGC Seimi Chemical Co., Ltd., and methyl ethyl ketone (MEK) as a solvent in the formulation shown in Table 1. The chemical structures of “Paliocolor LC242”, “Paliocolor LC756”, and “Irgacure OXE02” are shown below.

[0105] [Chemical Formula]

[0106] [Table 1]

[0107] (1-2. Preparation of Cholesteric Resin Layer) The cholesteric liquid crystal composition prepared as described above was applied onto a cycloolefin polymer (COP) film using a #10 wire bar to form a coating film of the liquid crystal composition. The coating film of the liquid crystal composition was held at 140 °C for 2 minutes for alignment treatment, and then a process consisting of irradiation treatment with weak ultraviolet light (wavelength 365 nm) of 25 mJ / cm 2 followed by heating treatment at 90 °C for 1 minute was carried out, and then 2000 mJ / cm 2The film was irradiated with ultraviolet rays to cure the coating film. As a result, a film F having a circular polarization separation function, in which a cholesteric resin layer with a thickness of 5 μm was formed on a PET film, was produced. Regarding the cholesteric resin layer, the light reflectance was measured using "V570" manufactured by JASCO Corporation in the wavelength range of 380 nm to 830 nm. As a result, the reflectance was 40% or more at at least one wavelength in the range of 380 nm or more and 830 nm or less. From the obtained reflectance spectrum, when the wavelength range (half-value width) that is half of the maximum reflectance was read in the reflection band where the reflectance was 35% or more and 50% or less, it was 350 nm. That the cholesteric resin layer reflects right circularly polarized light was confirmed by observing the cholesteric resin layer through a right circular polarizing plate. Here, the right circular polarizing plate has a function of absorbing left circularly polarized light and transmitting right circularly polarized light. Specifically, it was confirmed by observing the reflected light from the cholesteric resin layer through the right circular polarizing plate and seeing the colored reflected light.

[0108] (1-3. Production of fragments (resin pigments) of the cholesteric resin layer) As described below, referring to the method described in the examples of JP-A-2015-027743, the cholesteric resin layer was peeled off from the film F to obtain fragments, which were used as resin pigments.

[0109] A manufacturing apparatus including a film feeding unit, a peeling unit, and a film recovery unit was prepared. The peeling unit included a bar having an angular portion provided at an acute angle and a nozzle capable of injecting air provided immediately downstream of the angular portion. At this time, the angle of the angular portion of the bar was set so that the film F could be folded back at an angle θ = 30° to 60°. The angular portion had a chamfered structure with R = 0.2 mm to 0.3 mm.

[0110] The film F was attached to the film delivery section in a direction in which the film F could be folded back with the cholesteric resin layer facing outside the PET film at the corner of the bar. Then, the film F was sent out from the film delivery section while applying tension to the film F in the conveyance direction by the film recovery section. At this time, the magnitude of the tension applied to the film was set to 80 N / m. Also, air was ejected from the nozzle at a pressure of 0.5 MPa.

[0111] The film F began to stretch in the conveyance direction from the time it was sent out from the film delivery section. Further, thereafter, the film F that had stretched beyond the tensile fracture elongation of the cholesteric resin layer was folded back at the corner of the bar, and more cracks were formed.

[0112] Thereafter, the film F was conveyed to the nozzle and air was blown onto it from the nozzle. Due to this air, the cholesteric resin layer in which cracks had been formed became exfoliation pieces and was blown away.

[0113] Thereafter, the obtained exfoliation pieces of the cholesteric resin layer were recovered by a recovery device. Also, the PET film from which the cholesteric resin layer had been exfoliated was wound up in a roll shape and recovered by the film recovery section.

[0114] The recovered exfoliation pieces were pulverized with a cutter mill to form pieces of the cholesteric resin layer, and then passed through a sieve with a mesh size of 51 μm. The pieces of the cholesteric resin layer that passed through the sieve were recovered to form a resin pigment. Since the pieces of the resin layer that constitute the resin pigment are manufactured using the cholesteric resin layer provided in the film F as a raw material, they have the same cholesteric regularity in the same twist direction as the cholesteric resin layer provided in the film F.

[0115] (1-4. Preparation of Ink Containing Resin Pigment) The obtained resin pigment was added to a thermosetting medium ("LOV(E)-800" manufactured by Seiko Advance Co., Ltd.) so as to be 8% by weight based on the total amount of the ink, and used as Ink 1 for forming the first printing layer.

[0116] (Preparation of Ink Containing Metal Pigment) Aluminum powder (Standard No. 60 manufactured by Horikane Foil Powder Co., Ltd.) was added to a thermosetting medium (LOV(E)-800 manufactured by Seiko Advance Co., Ltd.) so as to be 10% by weight based on the total amount of the ink, and Ink 2 for forming the second printing layer was obtained.

[0117] (Manufacture of Genuine / Fake Judgment Member) On the surface of the cholesteric resin layer of the film F as the base material layer 10, the first printing layer 20 and the second printing layer 30 were formed by the screen printing method using Ink 1 and Ink 2 respectively so as to have the pattern shown in FIG. 1, and the genuine / fake judgment member 100 was manufactured.

[0118] (Step (1)) The genuine / fake judgment member 100 was placed on white paper with the surface (referred to as the main surface 10U) on which the first printing layer 20 and the second printing layer 30 were printed facing up. The genuine / fake judgment member 100 placed on the white paper was irradiated with non-polarized light from the side of the main surface 10U, and the reflected image was observed from the side of the main surface 10U. As a result, as shown in FIG. 5, the number "8" was observed. The observed number "8" as the reflected image (1) was silver.

[0119] (Step (2)) Next, the genuine / fake judgment member 100 was turned over with the axis R1 shown in FIG. 5 as the axis, and placed on white paper with the surface (referred to as the main surface 10D) on which the first printing layer 20 and the second printing layer 30 were not printed facing up. The genuine / fake judgment member 100 was irradiated with non-polarized light from the side of the main surface 10D, and the reflected image was observed from the side of the main surface 10D. As a result, the reflected light from the first printing layer 20 was not observed, the reflected light from the second printing layer 30 was observed, and as shown in FIG. 6, the number "5" was observed. The observed number "5" as the reflected image (2) was silver.

[0120] (Step (3)) The number "8" as the reflected image (1) and the number "5" as the reflected image (2) are clearly different and not in a mirror image relationship.

[0121] [Example 2] (Manufacture of Genuine / Fake Judgment Member) As the base material layer, a reflective circular polarizer containing a reflective linear polarizer was prepared. This reflective circular polarizer has two retardation layers (Zeonor Film ZD series manufactured by Nippon Zeon Co., Ltd.) having the function of a λ / 4 plate laminated on both sides of a reflective linear polarizer ("DBEF" manufactured by 3M). In this circular polarizing plate, two retardation layers are arranged on both sides of the reflective linear polarizer so that the transmitted light becomes left-handed circularly polarized light. On one surface of the base material layer, a triangular pattern was printed by screen printing using Ink 1 as the first printing layer, and a triangular outline pattern was printed by screen printing using Ink 2 as the second printing layer to manufacture a genuine / fake judgment member. The pattern printed with Ink 2 follows the outline of the triangular pattern printed with Ink 1. Ink 1 and Ink 2 were adjusted in the same manner as in Example 1.

[0122] (2-7. Step (1)) Next, the genuine / fake judgment member was placed on white paper with the surface (referred to as the first main surface) on which the first printing layer and the second printing layer were printed facing up. The genuine / fake judgment member placed on the white paper was irradiated with non-polarized light from the first main surface side, and the reflected image was observed from the first main surface side. As a result, the reflected light from the first printing layer and the second printing layer was observed, and a triangle was observed. The triangle as the observed reflected image (1) was silver.

[0123] (2-8. Step (2)) Next, the genuine / fake judgment member was turned over and placed on white paper with the surface (referred to as the second main surface) on which the first printing layer and the second printing layer were not printed facing up. The genuine / fake judgment member was irradiated with non-polarized light from the second main surface side, and the reflected image was observed from the second main surface side. As a result, the reflected light from the first printing layer (triangular pattern) was not observed, the reflected light from the second printing layer (triangular outline pattern) was observed, and only the outline of the triangle was observed. The outline of the triangle as the observed reflected image (2) was silver.

[0124] (2-9. Engineering (3)) The triangle as the reflection image (1) and the outline of the triangle as the reflection image (2) are clearly different and not in a mirror image relationship. Also, the outline of the triangle as the reflection image (2) was silver, not black, and was the same as the color of the outline of the triangle in the reflection image (1).

[0125] [Comparative Example 1] (C1-6. Manufacturing of the authenticity determination member) As the base material layer 510, an absorption type circular polarizing plate was prepared. This circular polarizing plate is formed by laminating a retardation layer 512 and a retardation layer 513 (both "Zeonor Film ZD series" manufactured by Nippon Zeon Co., Ltd.), which have the function of a λ / 4 plate, on both sides of an absorption type linear polarizer 511 ("HLC2-5618S" manufactured by Sunlite Co., Ltd.). In this circular polarizing plate, the retardation layer 512, the retardation layer 513, and the linear polarizer 511 are arranged so that the transmitted light becomes left circularly polarized light. On the surface of the base material layer 510 on the side of the retardation layer 512, the first printing layer 520 and the second printing layer 530 were formed by screen printing using ink 1 and ink 2, respectively, so as to have the pattern shown in FIG. 7, and the authenticity determination member 500 was manufactured. Ink 1 and ink 2 were prepared in the same manner as in Example 1.

[0126] (C1-7. Step (1)) Next, the authenticity determination member 500 was placed on white paper with the surface (referred to as the main surface 510U) on which the first printing layer 520 and the second printing layer 530 were printed facing up. The authenticity determination member 500 placed on the white paper was irradiated with non-polarized light from the side of the main surface 510U, and the reflection image was observed from the side of the main surface 510U. As a result, the number "8" was observed. The observed number "8" as the reflection image (1) was silver.

[0127] (C1-8. Step (2)) Next, the authenticity determination member 500 was turned over with the vertical direction of the paper surface of FIG. 7 as the axis, and placed on white paper with the surface on which the first printing layer 520 and the second printing layer 530 were not printed (referred to as the main surface 510D) facing up. The authenticity determination member 500 was irradiated with non-polarized light from the side of the main surface 510D, and the reflected image was observed from the side of the main surface 510D. As a result, no silver-colored reflected image was observed, and only the black numeral "5" was observed.

[0128] (C1-9. Step (3)) As described above, the reflected image (1) was obtained, but the silver-colored reflected image (2) was not obtained.

Explanation of Signs

[0129] 10 Substrate layer 10U Main surface 10D Main surface 100 Authenticity determination member 20 First printing layer 30 Second printing layer 500 Authenticity determination member 510 Substrate layer 510U Main surface 510D Main surface 511 Linear polarizer 512 Retardation layer 513 Retardation layer 520 First printing layer 530 Second printing layer

Claims

1. a base material layer which is a reflective circular polarizer, a first printed layer provided on the base material layer, including a resin pigment which is a fragment of a resin layer A1 having a cholesteric regularity, a counterfeit determination member including a second printed layer provided on the base material layer, including a metal pigment having no circular polarization separation function.

2. The counterfeit determination member according to claim 1, wherein a reflected image (1) observed by making non-polarized light incident from one main surface side of the counterfeit determination member and a reflected image (2) observed by making non-polarized light incident from the other main surface side of the counterfeit determination member are different.

3. The counterfeit determination member according to claim 1 or 2, wherein the resin layer A1 has a reflectance of 40% or more at at least one wavelength in the visible wavelength band, and a half-value width of a reflection band having a reflectance of 35% or more and 50% or less is 350 nm or more.

4. The counterfeit determination member according to any one of claims 1 to 3, wherein the base material layer is a resin layer A2 having a cholesteric regularity, and the resin layer A1 and the resin layer A2 have a cholesteric regularity in the same twist direction.

5. The counterfeit determination member according to claim 4, wherein the resin layer A2 has a reflectance of 40% or more at at least one wavelength in the visible wavelength band, and a half-value width of a reflection band having a reflectance of 35% or more and 50% or less is 350 nm or more.

6. The counterfeit determination member according to claim 1 or 2, wherein the base material layer is a reflective circular polarizer including a reflective linear polarizer, a first λ / 4 plate provided on one main surface of the reflective linear polarizer, and a second λ / 4 plate provided on the other main surface of the reflective linear polarizer.

7. Step (1) of observing by making non-polarized light incident from one main surface side of the counterfeit determination member according to any one of claims 1 to 6 to obtain a reflected image (1), Step (2) of observing by making non-polarized light incident from the other main surface side of the counterfeit determination member to obtain a reflected image (2), and A method for determining the authenticity of a counterfeit determination member, including step (3) of determining that the reflected image (1) and the reflected image (2) are different.

Images