JP4423920B2 - Identifying mark - Google Patents

Description

  The present invention relates to an identification mark for preventing counterfeiting of cards, gift certificates, securities, identification cards, banknotes, licenses, and the like.

  Cards, gift certificates, securities, identification cards, banknotes, licenses, etc. have direct or indirect economic or other value, so damage such as forgery, alteration, alteration, etc. It is easy to suffer. For the purpose of preventing such forgery, alteration, alteration, etc., an identification mark that is difficult to forge is provided on at least a part of the target article. The presence or absence of these identification marks is determined visually or by using a machine, and the target article provided with the genuine identification mark is determined to be true, and the other articles are determined to be false.

  Conventionally, as an identification mark, an identification mark using a fluorescent material has been widely used. This is because fluorescent light emission is induced by irradiating an identification mark that is invisible under normal light rays with excitation light of a specific wavelength, and an authentic fluorescent material is identified by the presence or absence of the light emission or the color of the light emission. It is determined whether or not the identification mark is used, and the authenticity of the identification mark, and hence the authenticity of the article provided with the identification mark is determined.

  However, identification marks using fluorescent materials have the greatest anti-counterfeiting effect due to the fact that their presence is not clear, and once the presence is known, it is relatively easy to obtain fluorescent materials. Therefore, the effect of preventing forgery is remarkably reduced. In addition, as an excitation light source for fluorescent materials, ultraviolet rays are mostly used, but ultraviolet irradiation devices such as black light are generally used, and the presence of identification marks using fluorescent materials. The danger of knowing is increasing.

  In addition, rare earth complexes are generally used as fluorescent materials because they have high color purity and are stable against repeated excitation. In these rare earth complexes, fluorescent light emission occurs with rare earth elements as the emission center. Therefore, the emission center wavelength largely depends on the kind of rare earth element. Therefore, even if the type of ligand of the complex is changed, it is difficult to give a large change to the central wavelength (that is, the color tone) of the light emission itself, and the types of emission colors of fluorescent light emission are relatively limited. Therefore, there is a limit to the creation of the identification mark by identifying the fluorescence emission color.

  Therefore, as a fluorescent material with improved anti-counterfeiting properties, it has a unidirectional alignment structure so as to emit polarized intrinsic wavelength fluorescence or phosphorescence when illuminated with excitation light corresponding to the absorption band of the fluorescent material. There is disclosed a system for detecting the authenticity of an article using an identification mark characterized by the above and the polarization property of the fluorescence (see Patent Document 1). This is intended to enhance the anti-counterfeiting effect by detecting not only the presence / absence of fluorescence as an identification mark but also the polarization state of fluorescence.

  However, in this system, the direction of linearly polarized light of fluorescence is detected by observation through a polarizing plate, and at the present time when the polarizing plate is relatively easy to obtain, it cannot be an advanced anti-counterfeiting system.

  In addition, it is necessary to provide the identification mark with a unidirectional alignment structure so as to impart polarized light to the fluorescence, and there is a great restriction on the method of manufacturing the identification mark. For example, this patent discloses a film stretching method as a method for providing a unidirectional alignment structure. This is a method in which a film in which a fluorescent material is dispersed is stretched in one direction, and the fluorescent material is aligned in the film to impart polarization to the fluorescence. That is, in the method disclosed in this patent, it is necessary to create a film-like fluorescent light-emitting element once and then process the element into the shape of an identification mark. Therefore, it is very difficult to provide a mark having an alignment structure in an arbitrary direction in an arbitrary shape, and there is a problem that processing becomes complicated.

This patent also discloses a method of detecting the circularly polarized state by using a circularly polarizing plate by converting the linearly polarized light of the emitted fluorescence into circularly polarized light using a quarter-wave plate. ing. However, in this method, the polarized light obtained by the above method is detected by simply converting it into circularly polarized light, and the mechanism of the fluorescent light emitting portion is the same as in the case of polarized light emission. Furthermore, in this method, since it is circularly polarized over the entire wavelength region of the fluorescent light emission, it is easy to reveal that the fluorescent light emission is circularly polarized, and it cannot be an advanced anti-counterfeiting system. In addition, an additional quarter-wave plate needs to be added, and the layer structure of the identification mark itself becomes complicated.
JP 2001-506191 A

  An object of the present invention is to provide an identification mark that is more difficult to counterfeit than a conventional identification mark.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using an identification mark containing an optically active rare earth complex.

  That is, the present invention relates to an identification mark containing at least a rare earth complex, wherein the rare earth complex is represented by the general formula (1)

（式中、Ｘ_１及びＸ_２はそれぞれ独立に、水素原子、ハロゲン原子、炭素数１〜４のアルキル基、及び炭素数１〜４のアルコキシル基からなる群のうちいずれか一つを表し、Ｙ_１、Ｙ_２、Ｙ_３およびＹ_４はそれぞれ独立に水素原子、ハロゲン原子、及び炭素数１〜４のアルキル基からなる群のうちいずれか一つを表す）で表される二座のホスフィンオキシド配位子を１つまたは２つ含有してなる光学活性希土類錯体であることを特徴とする識別マークを提供する。
また、本発明は、希土類錯体が一般式（２）

(Wherein, X ₁ and X ₂ each independently represent any one of a group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxyl group having 1 to 4 carbon atoms, Y ₁ , Y ₂ , Y ₃ and Y ₄ each independently represents a hydrogen atom, a halogen atom, or a C 1-4 alkyl group, and a bidentate phosphine represented by Provided is an identification mark, which is an optically active rare earth complex containing one or two oxide ligands.
In the present invention, the rare earth complex is represented by the general formula (2).

（式中、Ｘ_１、Ｘ_２、Ｙ_１、Ｙ_２、Ｙ_３およびＹ_４は一般式（１）においてと同じ意味を表し、Ｒ_１、Ｒ_２はそれぞれ独立に、炭素数１〜２０のアルキル基、炭素数１〜２０のフッ素置換アルキル基、水酸基、ニトロ基、アミノ基、シアノ基、メルカプト基、炭素数１〜４のアルキルスルホニル基、炭素数１〜４のアルキルチオ基、炭素数１〜４のアルキルシリル基、フェニルスルホニル基、フェニルチオ基、フェニルシリル基、シクロペンタジエニル基（基中に存在する１個のＣＨ_２基はまた、−Ｏ−または−Ｓ−により置き換えられていてもよい）、フェニル基（基中に存在する１個または２個のＣＨ基はまた、Ｎにより置き換えられていてもよい）、又はナフチル基（基中に存在する１個または２個のＣＨ基はまた、Ｎにより置き換えられていてもよい）を表し、該フェニルスルホニル基、フェニルチオ基、フェニルシリル基、シクロペンタジエニル基、フェニル基、及びナフチル基は、非置換であるか又は置換基として１個または２個以上のハロゲン原子、又は炭素数１〜４のアルキル基を有することができ、Ｌｎは希土類金属原子を表す）で表される光学活性希土類錯体であることを特徴とする識別マークを提供する。
本発明の識別マークは、紫外線の照射により誘起される蛍光発光が円偏光性を示すため、その円偏光性を検出することによってセキュリティー性の高い真偽判定を行うことができる。
さらに本発明は前記識別マークを設けるために使用される転写箔であって、仮支持体フィルム上に、光学活性希土類錯体を含有する蛍光発光層、及び接着剤層をこの順に積層したことを特徴とする転写箔を提供する。
さらにまた本発明は前記識別マークを設けるために使用されるラベルであって、支持体フィルム上の一方の側に、光学活性希土類錯体を含有する蛍光発光層を有し、他方の側に接着剤層を有することを特徴とするラベルを提供する。
このような転写箔やラベルを用いることによって、カードや身分証明書、紙幣の他にも種々の対象物品に本発明の識別マークを形成することができる。

(In the formula, X ₁ , X ₂ , Y ₁ , Y ₂ , Y ₃ and Y ₄ represent the same meaning as in general formula (1), and R ₁ and R ₂ each independently has 1 to 20 carbon atoms. Alkyl group, fluorine-substituted alkyl group having 1 to 20 carbon atoms, hydroxyl group, nitro group, amino group, cyano group, mercapto group, alkylsulfonyl group having 1 to 4 carbon atoms, alkylthio group having 1 to 4 carbon atoms, carbon number 1 to 4 alkylsilyl group, phenylsulfonyl group, a phenylthio group, triphenylsilyl group, and the one CH ₂ group existing in the cyclopentadienyl group (group, be replaced by -O- or -S- ), A phenyl group (one or two CH groups present in the group may also be replaced by N), or a naphthyl group (one or two CH groups present in the group). Also by N The phenylsulfonyl group, phenylthio group, phenylsilyl group, cyclopentadienyl group, phenyl group, and naphthyl group may be unsubstituted or substituted as one or two substituents. An identification mark characterized by being an optically active rare earth complex represented by the above-described halogen atom or an alkyl group having 1 to 4 carbon atoms, wherein Ln represents a rare earth metal atom).
In the identification mark of the present invention, since fluorescence emitted by irradiation with ultraviolet rays exhibits circular polarization, true / false determination with high security can be performed by detecting the circular polarization.
Furthermore, the present invention provides a transfer foil used for providing the identification mark, wherein a fluorescent light emitting layer containing an optically active rare earth complex and an adhesive layer are laminated in this order on a temporary support film. A transfer foil is provided.
Furthermore, the present invention is a label used for providing the identification mark, which has a fluorescent light-emitting layer containing an optically active rare earth complex on one side on a support film, and an adhesive on the other side. A label characterized by having a layer is provided.
By using such a transfer foil or label, the identification mark of the present invention can be formed on various target articles in addition to cards, identification cards, and banknotes.

  According to the present invention, an identification mark with higher security can be provided as compared with an identification mark using a conventional fluorescent material.

  The optically active rare earth complex of the present invention refers to a rare earth complex having an optically active site, and is a rare earth complex in which a ligand having an optically active site is coordinated, or a square-rectal prism type of a rare earth complex. This refers to a rare earth complex in which one of the two stereoisomers of a Δ-form and a Λ-form existing with respect to the absolute configuration around the rare earth metal atom in the coordination structure is excessively contained.

  In the present invention, as a ligand having an optically active site, the following general formula (1)

（式中、Ｘ_１及びＸ_２はそれぞれ独立に、水素原子、ハロゲン原子、炭素数１〜４のアルキル基、及び炭素数１〜４のアルコキシル基からなる群のうちいずれか一つを表し、Ｙ_１、Ｙ_２、Ｙ_３およびＹ_４はそれぞれ独立に水素原子、ハロゲン原子、及び炭素数１〜４のアルキル基からなる群のうちいずれか一つを表す）で表される配位子（以下、配位子（１）と言う。）を用いた。配位子（１）はビナフチル基の部分に軸不斉を有するため、２種の光学異性体が存在する。以下、この２種の異性体をＲとＳで区別する。
本発明で用いる配位子（１）を含有する光学活性希土類錯体の好ましい態様としては、下記一般式（３）

(Wherein, X ₁ and X ₂ each independently represent any one of a group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxyl group having 1 to 4 carbon atoms, Y ₁ , Y ₂ , Y _3, and Y ₄ each independently represent a hydrogen atom, a halogen atom, and a ligand represented by a ligand represented by any one of the groups consisting of alkyl groups having 1 to 4 carbon atoms ( Hereinafter, the ligand (1) is used). Since the ligand (1) has axial asymmetry at the binaphthyl group, there are two optical isomers. Hereinafter, these two isomers are distinguished by R and S.
As a preferable aspect of the optically active rare earth complex containing the ligand (1) used in the present invention, the following general formula (3)

（式中、Ｘ_１、Ｘ_２、Ｙ_１、Ｙ_２、Ｙ_３およびＹ_４は一般式（１）においてと同じ意味を表し、Ｌｎは希土類原子を表し、Ｌはアニオン性配位子を表し、ｍは２または３を、ｎは１または２を表す）で示される。アニオン性配位子Ｌとしては、例えば、一般式（４）

(Wherein X ₁ , X ₂ , Y ₁ , Y ₂ , Y ₃ and Y ₄ represent the same meaning as in general formula (1), Ln represents a rare earth atom, and L represents an anionic ligand. , M represents 2 or 3, and n represents 1 or 2. Examples of the anionic ligand L include the general formula (4)

で表されるピラゾロン配位子、一般式（５）

A pyrazolone ligand represented by the general formula (5)

で表されるキノリノール配位子、一般式（６）

A quinolinol ligand represented by the general formula (6)

で表されるビススルホニルアミド配位子、一般式（７）

A bissulfonylamide ligand represented by the general formula (7)

で表されるβ−ジケトン配位子（一般式（４）〜（７）中、Ｒ_３、Ｒ_４およびＲ_５は、それぞれ独立に、炭素数１〜２０のアルキル基、炭素数１〜２０のフッ素置換アルキル基、水酸基、ニトロ基、アミノ基、シアノ基、メルカプト基、炭素数１〜４のアルキルスルホニル基、アルキルチオ基及びアルキルシリル基、置換基を有してもよいフェニルスルホニル基、フェニルチオ基及びフェニルシリル基、アリール基、及びヘテロアリール基からなる群のうちいずれか一つを表す。）等が挙げられるが、好ましくはβ−ジケトン配位子である。また、ｍは３が好ましく、ｎは１が好ましい。
したがって、本発明に用いられる光学活性希土類錯体のより好ましい態様は、一般式（２）

Β-diketone ligand represented by the formula (in the general formulas (4) to (7), R ₃ , R ₄ and R ₅ are each independently an alkyl group having 1 to 20 carbon atoms, or 1 to 20 carbon atoms). Fluorine-substituted alkyl group, hydroxyl group, nitro group, amino group, cyano group, mercapto group, alkylsulfonyl group having 1 to 4 carbon atoms, alkylthio group and alkylsilyl group, phenylsulfonyl group optionally having substituent, phenylthio Group and a phenylsilyl group, an aryl group, and a heteroaryl group, and the like.), And the like are preferable, and a β-diketone ligand is preferable. Further, m is preferably 3, and n is preferably 1.
Therefore, a more preferable embodiment of the optically active rare earth complex used in the present invention is represented by the general formula (2).

（式中、Ｘ_１、Ｘ_２、Ｙ_１、Ｙ_２、Ｙ_３およびＹ_４は一般式（１）においてと同じ意味を表し、Ｒ_１、Ｒ_２はそれぞれ独立に、炭素数１〜２０のアルキル基、炭素数１〜２０のフッ素置換アルキル基、水酸基、ニトロ基、アミノ基、シアノ基、ルカプト基、炭素数１〜４のアルキルスルホニル基、炭素数１〜４のアルキルチオ基、炭素数１〜４のアルキルシリル基、フェニルスルホニル基、フェニルチオ基、フェニルシリル基、シクロペンタジエニル基（基中に存在する１個のＣＨ_２基はまた、−Ｏ−または−Ｓ−により置き換えられていてもよい）、フェニル基（基中に存在する１個または２個のＣＨ基はまた、Ｎにより置き換えられていてもよい）、又はナフチル基（基中に存在する１個または２個のＣＨ基はまた、Ｎにより置き換えられていてもよい）を表し、該フェニルスルホニル基、フェニルチオ基、フェニルシリル基、シクロペンタジエニル基、フェニル基、及びナフチル基は、非置換であるか又は置換基として１個または２個以上のハロゲン原子、又は炭素数１〜４のアルキル基を有することができ、Ｌｎは希土類金属原子を表す）で表される。
一般式（２）においてハロゲン原子はフッ素または塩素であることが好ましい。
さらに好ましくは、一般式（２）において、Ｘ_１およびＸ_２は水素原子が好ましい。Ｙ_１、Ｙ_２、Ｙ_３およびＹ_４は水素原子が好ましい。Ｒ_１は、炭素数１〜８のアルキル基、炭素数１〜８のフッ素置換アルキル基、またはフェニル基が好ましい。Ｒ_２は、
（ａ）シクロペンタジエニル基（基中に存在する１個のＣＨ_２基はまた、−Ｏ−または−Ｓ−により置き換えられていてもよい）、
（ｂ）フェニル基（基中に存在する１個または２個のＣＨ基はまた、Ｎにより置き換えられていてもよい）、
（ｃ）ナフチル基（基中に存在する１個または２個のＣＨ基はまた、Ｎにより置き換えられていてもよい）、
からなる群から選ばれる基、及びこれらの基のアルキル基置換体またはハロゲン原子置換体が好ましい。ＬｎはＥｕが好ましい。
さらには、Ｒ_１はトリフルオロメチル基が最も好ましく、Ｒ_２は、チエニル基が最も好ましい。

(In the formula, X ₁ , X ₂ , Y ₁ , Y ₂ , Y ₃ and Y ₄ represent the same meaning as in general formula (1), and R ₁ and R ₂ each independently has 1 to 20 carbon atoms. Alkyl group, fluorine-substituted alkyl group having 1 to 20 carbon atoms, hydroxyl group, nitro group, amino group, cyano group, lucapto group, alkylsulfonyl group having 1 to 4 carbon atoms, alkylthio group having 1 to 4 carbon atoms, carbon number 1 to 4 alkylsilyl group, phenylsulfonyl group, a phenylthio group, triphenylsilyl group, and the one CH ₂ group existing in the cyclopentadienyl group (group, be replaced by -O- or -S- ), A phenyl group (one or two CH groups present in the group may also be replaced by N), or a naphthyl group (one or two CH groups present in the group). Also by N The phenylsulfonyl group, phenylthio group, phenylsilyl group, cyclopentadienyl group, phenyl group, and naphthyl group may be unsubstituted or substituted as one or two substituents. It can have one or more halogen atoms or an alkyl group having 1 to 4 carbon atoms, and Ln represents a rare earth metal atom).
In general formula (2), the halogen atom is preferably fluorine or chlorine.
More preferably, in the general formula (2), X ₁ and X ₂ are preferably hydrogen atoms. Y ₁ , Y ₂ , Y ₃ and Y ₄ are preferably hydrogen atoms. R ₁ is preferably an alkyl group having 1 to 8 carbon atoms, a fluorine-substituted alkyl group having 1 to 8 carbon atoms, or a phenyl group. R ₂ is
(A) a cyclopentadienyl group (one CH ₂ group present in the group may also be replaced by —O— or —S—),
(B) a phenyl group (one or two CH groups present in the group may also be replaced by N),
(C) a naphthyl group (one or two CH groups present in the group may also be replaced by N),
A group selected from the group consisting of these, and an alkyl group-substituted or halogen atom-substituted group of these groups are preferred. Ln is preferably Eu.
Further, R ₁ is most preferably a trifluoromethyl group, and R ₂ is most preferably a thienyl group.

In the case of the optically active rare earth complex represented by the general formula (2), the diastereoselectivity of the ligand (1) corresponds to the enantiomer (R isomer, S isomer) of the ligand (1), Stereoisomerism (Δ form, Λ form) of rare earth complexes can be selectively generated.
Here, the diastereoselectivity of a ligand is a ligand in which two kinds of enantiomers are present (hereinafter referred to as R and S), and one of the enantiomers (for example, an R-form ligand). ) Is used to form a complex with a rare earth, which means that one stereoisomer of the rare earth complex (for example, a Δ rare earth complex) is selectively formed. That is, for example, when a rare earth complex is formed using an R-form ligand, the rare earth complex is one of the stereoisomers of the R-Δ and R-Λ isomers in a diastereomeric relationship. For example, it refers to the property that only the R-Δ form is generated. Ligands with diastereoselectivity may have more than two stereoisomers.

That is, in the present invention, the characteristics of the optically active rare earth complex (2) are attributed to optically active isomers having the following two structures.
One of them is represented by the general formula (2-1)

（式中、点線の円弧は一般式（２−１ａ）

(In the formula, the dotted arc represents the general formula (2-1a).

（式中Ｒ_１、Ｒ_２は一般式（２）においてと同じ意味を表す。）で示される配位子を、実線の円弧は一般式（２−１ｂ）

(Wherein R ₁ and R ₂ represent the same meaning as in the general formula (2)), the solid arc represents the general formula (2-1b)

（式中Ｘ_１、Ｘ_２、Ｙ_１、Ｙ_２、Ｙ_３、Ｙ_４は一般式（２）においてと同じ意味を表す。）で示される配位子を表す。）で表されるＲ−Δ構造を有する希土類錯体（２）(以下Ｒ−Δ希土類錯体（２）と言う。)である。
さらにもう一方は、一般式（２−２）

(Wherein X ₁ , X ₂ , Y ₁ , Y ₂ , Y ₃ , Y ₄ represent the same meaning as in general formula (2)). ) Represented by a rare earth complex (2) (hereinafter referred to as R-Δ rare earth complex (2)).
Furthermore, the other is the general formula (2-2)

（式中、点線の円弧は一般式（２−１ａ）で示される配位子を、実線の円弧は一般式（２−２ｂ）

(In the formula, the dotted arc represents the ligand represented by the general formula (2-1a), and the solid arc represents the general formula (2-2b).

（式中Ｘ_１、Ｘ_２、Ｙ_１、Ｙ_２、Ｙ_３、Ｙ_４は一般式（２）においてと同じ意味を表す。）で示される配位子を表す。）で表されるＳ−Λ構造を有する希土類錯体（２）（以下、Ｓ−Λ希土類錯体（２）と言う。）である。

(Wherein X ₁ , X ₂ , Y ₁ , Y ₂ , Y ₃ , Y ₄ represent the same meaning as in general formula (2)). ) Represented by a rare earth complex (2) having an S-Λ structure (hereinafter referred to as S-Λ rare earth complex (2)).

  Various methods can be used to determine whether the identification mark of the present invention contains the optically active rare earth complex containing the ligand (1). Most preferably.

Examples of the optically active rare earth complex containing the ligand (1) of the present invention include a point that fluorescence emission induced by ultraviolet irradiation exhibits circularly polarized light emission. Here, the circularly polarized light-emitting property represents a property that, for example, in a compound that emits fluorescence or phosphorescence upon irradiation with ultraviolet rays, the left and right circularly polarized light components included in the fluorescence or phosphorescence emitted from the compound are different. That is, the intensity of the right circularly polarized component of the emitted fluorescence or phosphorescence and I _R, the intensity of left-handed circularly polarized light component and I _L, the following equation

で表されるｇ値を定義したとき、ｇ≠０となる光を放射する性質である。

When the g value represented by is defined, it is a property of emitting light satisfying g ≠ 0.

  Therefore, whether the identification mark of the present invention is obtained by measuring the difference between the intensity of the right circularly polarized light component and the intensity of the left circularly polarized light component in the fluorescence emission of the identification mark provided on the article, or the above g value. It becomes possible to determine whether or not.

  In the circularly polarized light emitted from the printing layer (1), the fluorescence itself has a circularly polarizing property, and the degree of circular polarization has a wavelength dependency. Accordingly, when the entire light in a wide wavelength region is visually observed through a normal circularly polarizing plate, it is difficult to reveal the presence of circularly polarized light in a specific wavelength region, and the anti-counterfeiting property is remarkably improved. For example, if the degree of circularly polarized light at the main peak is small and the degree of circularly polarized light at the sub-peak is large among the light emitted from a plurality of wavelength regions constituting the fluorescent light emission, the main peak is also observed in the observation through the circularly polarizing plate. Is observed through the circularly polarizing plate, it is very difficult to detect the fact even if the degree of shielding of the sub-peak is different between the two circularly polarizing plates. Therefore, by adopting the presence / absence of the circularly polarized light emission of the sub-peak as an identification means, it becomes possible to construct a system with very high security.

  The circularly polarized light emitted from the fluorescent light-emitting layer of the identification mark of the present invention has a structure of an optically active rare earth complex containing the ligand (1), in which the fluorescence itself has circular polarization. In addition, it has wavelength dependency of the degree of circular polarization. Accordingly, when the entire light in a wide wavelength region is visually observed through a normal circularly polarizing plate, it is difficult to reveal the presence of circularly polarized light in a specific wavelength region, and the anti-counterfeiting property is remarkably improved. For example, if the degree of circularly polarized light at the main peak is small and the degree of circularly polarized light at the sub-peak is large among the light emitted from a plurality of wavelength regions constituting the fluorescent light emission, the main peak is also observed in the observation through the circularly polarizing plate. Is observed through the circularly polarizing plate, it is very difficult to detect the fact even if the degree of shielding of the sub-peak is different between the two circularly polarizing plates. Therefore, by adopting the presence / absence of the circularly polarized light emission of the sub-peak as an identification mark identifying means, it is possible to construct a system with very high security.

  In addition, as already mentioned, it is relatively easy to circularly polarize over the entire wavelength region of fluorescent light emission, but it is technically very difficult to circularly polarize only a specific wavelength region. It is impossible to create a highly secure identification mark having the same effect as described above by another method.

Furthermore, the identification mark disclosed in the present invention can realize circularly polarized light emission without performing any special post-processing because the fluorescent light itself is circularly polarized light. Therefore, it is not necessary to give special consideration to the creation of the identification mark, and the productivity is excellent.
As a method for producing an optically active rare earth complex containing the ligand (1), for example, in water, an organic solvent such as alcohol or acetone, or a mixed solvent of water and an organic solvent, the following general formula (8)

（式中、Ｘ_１、Ｘ_２、Ｙ_１、Ｙ_２、Ｙ_３およびＹ_４は一般式（１）においてと同じ意味を表す。）で表される化合物、アニオン性配位子及び希土類金属の無機塩を混合し反応させる。あるいは、一般式（８）の化合物と下記一般式（９）

(Wherein X ₁ , X ₂ , Y ₁ , Y ₂ , Y ₃ and Y ₄ represent the same meaning as in the general formula (1)), an anionic ligand and a rare earth metal Inorganic salts are mixed and reacted. Alternatively, the compound of the general formula (8) and the following general formula (9)

（式中、Ｌｎ、Ｌ、ｍは一般式（３）においてと同じ意味を表す。）で表される希土類錯体またはその水和物を有機溶媒中混合し反応させる。反応は、−５０〜８０℃、好ましくは０〜４０℃で１〜２４時間攪拌して行う。一般式（８）の化合物は、例えば、Ｏｒｇ．Ｓｙｎｔｈ．，Ｃｏｌｌ．Ｖｏｌ．８ ５７（１９９３）に記載の方法で製造することができる。反応終了後、溶媒を留去して目的の光学活性希土類錯体を得ることができる。必要に応じて、例えば再結晶等の精製を行ってもよい。

(In the formula, Ln, L, and m have the same meaning as in general formula (3).) A rare earth complex represented by the general formula (3) or a hydrate thereof is mixed and reacted in an organic solvent. The reaction is carried out with stirring at -50 to 80 ° C, preferably 0 to 40 ° C for 1 to 24 hours. Compounds of general formula (8) are described, for example, in Org. Synth. , Coll. Vol. 8 57 (1993). After completion of the reaction, the solvent can be distilled off to obtain the desired optically active rare earth complex. If necessary, purification such as recrystallization may be performed.

  When the optically active rare earth complex containing the ligand (1) is used as a circularly polarized light emitting material, it is used in a state where any one of the two or more optical isomers is excessively contained. Preferably, the optical purity is preferably 90% or more, more preferably 95% or more.

  On the other hand, it is also possible in principle to separate only the Δ form or only the Λ form from the so-called racemic mixture, which is a mixture of two stereoisomers of the Δ form and the Λ form, and exhibit the same effect. However, it is very difficult to resolve such optical isomers. As a result, the rare earth complexes obtained are very expensive and are not practically used in terms of cost. In addition, it is very difficult to obtain a rare earth complex having high optical purity, and as a result, the complex becomes a circularly polarized light-emitting complex, so that it is difficult to apply as an identification mark.

  The shape of the identification mark of the present invention is not particularly limited. For example, an identification mark provided by transferring the transfer foil, an identification mark provided by attaching a label, and the like can be mentioned, but the invention is not limited thereto.

As an example, FIG. 1 shows a cross-sectional configuration diagram of a transfer foil for forming an identification mark when a protective layer is laminated.

The transfer foil for forming the identification mark has the temporary support film 10, the fluorescent light emitting layer 12, and the adhesive layer 13 as a basic structure, but has a peelability from the temporary support film 10 and is transferred to the article. May be laminated with a protective layer 11 for protecting the surface as the outermost layer of the identification mark. When the fluorescent light emitting layer 12 has peelability from the temporary support film 10, the protective layer 11 can be omitted. However, in this case, the fluorescent light emitting layer 12 is directly exposed on the surface of the identification mark in the identification mark after transfer. Therefore, when considering the abrasion resistance of the identification mark, it is preferable to provide the protective layer 11. The protective layer 11, the fluorescent light emitting layer 12, and the adhesive 13 are preferably colorless and transparent under normal light. In this case, the presence of the transfer foil cannot be visually confirmed under normal light. Further, a colored layer may be provided between the fluorescent light emitting layer 12 and the adhesive layer 13. In this case, the hue of the colored layer is exposed so as to be visible under normal light.

  Any known conventional film can be used as the temporary support film 10. Examples thereof include polyesters such as polyethylene terephthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate, and plastics such as polyamide. Of these, polyethylene terephthalate having both tensile strength and heat resistance is preferred. Although there is no restriction | limiting in particular in the thickness of a temporary support body film, Usually, 3-100 micrometers, Preferably it is 5-50 micrometers.

  The protective layer 11 is mainly composed of a binder resin. Examples of the binder resin include cellulosic resins, butyral resins, acrylic resins, polyurethane resins, polyester resins, copolymers of vinyl chloride and vinyl acetate, or copolymers added with vinyl alcohol, maleic anhydride, acrylic acid, or the like. Examples thereof include vinyl chloride resins such as polymers, epoxy resins, phenol resins, melamine resins, and mixtures of these resins.

  The protective layer 11 can be obtained by, for example, applying a coating solution obtained by dissolving these binder resins in a solvent on a temporary support film.

  Examples of the solvent include ketones such as acetone, methyl ethyl ketone, and cyclohexanone, esters such as methyl acetate, ethyl acetate, and butyl acetate, alcohols such as ethanol, and hydrocarbons such as hexane, toluene, and xylene. These solvents can be used in combination of two or more.

  Furthermore, soy lecithin, microsilica, wax, or the like can be added to the protective layer 11 as a film modifier as required. In addition, it is preferable to add a curing agent such as a polyisocyanate compound to crosslink between the binder resin molecules in order to improve the durability of the protective layer 11.

  The fluorescent light emitting layer 12 contains at least the optically active rare earth complex already described, and usually has a composition in which this optically active rare earth complex is dispersed in a binder resin. The binder resin used for the fluorescent light emitting layer 12 is not particularly limited, but a binder resin having no absorption in the absorption wavelength region of the optically active rare earth complex and the fluorescent light emitting wavelength region is desirable. Etc. can be used.

  The fluorescent light emitting layer 12 can be obtained by coating or printing a coating solution prepared by dissolving and dispersing the binder resin and the fluorescent material in a solvent that dissolves the binder resin. As the solvent, the solvents described above can be used.

  The adhesive layer 13 is provided for bonding the transfer foil and the article, and has a binder resin having heat-sensitive adhesive as a main component. Examples of the resin exhibiting heat-sensitive adhesion include vinyl chloride resins such as copolymers of vinyl chloride and vinyl acetate, or copolymers added with vinyl alcohol, maleic anhydride or acrylic acid, and polyester resins. , Acrylic resin, polyimide resin, polyurethane resin and the like.

The coating solution for forming the protective layer and the fluorescent light emitting layer is applied onto the temporary support by a known method.
A transfer tape or a transfer sheet, which is a tape-like or sheet-like transfer foil, can be obtained by slitting and cutting the original transfer foil composed of these constituent layers to an arbitrary width.

  FIG. 2 shows a cross-sectional configuration diagram of an article provided with an identification mark using a transfer foil. The transfer foil for forming an identification mark shown in FIG. 1 is superposed so that the adhesive layer 13 is in contact with the article 14, and is adhered to the article by applying heat and pressure. Thereafter, the temporary support film 10 is peeled and removed, whereby an identification mark having the protective layer 11 as the outermost layer is provided on the surface of the article 14 as shown in FIG.

  FIG. 3 is a cross-sectional view of the identification mark forming label in which a protective layer and a release layer are laminated. The label for forming the identification mark has a basic configuration in which the fluorescent light emitting layer 16 is formed on one surface of the support film 15 and the adhesive adhesive layer 18 is formed on the other surface. A protective layer 17 may be further laminated on the fluorescent light emitting layer 16. A release paper 19 or the like may be laminated on the adhesive adhesive layer 18.

  Usually, such a label for forming an identification mark is obtained by forming or coating each constituent layer on the support film 15.

  Thereafter, the original fabric is cut into a sheet shape, or a label is produced by a method such as punching from the original fabric or the sheet. Further, the identification mark forming label does not limit the shape of the label, and for example, a label in a tape state can be prepared from a raw material by a method such as slitting.

  When affixing an identification mark to an article using these identification mark forming labels, if there is a release paper 19, the release paper is peeled off, and then the laminated structure including the fluorescent light emitting layer 16 is The product 14 is superposed on the product 14 through the adhesive adhesive layer 18 and is adhered to the product 14 by applying pressure and heat. FIG. 4 shows a cross-sectional configuration diagram of an article in which an identification mark is provided on the surface using an identification mark forming label.

  Any known support film 15 can be used. For example, the support film 15 described in the transfer foil for forming an identification mark can be used.

  Moreover, there is no restriction | limiting in particular in the thickness of a support body film, However, Usually, 10-100 micrometers, Preferably it is 20-80 micrometers.

  The fluorescent light emitting layer 16 contains at least an optically active rare earth complex, and usually has a composition in which this optically active rare earth complex is dissolved and dispersed in a binder resin. The binder resin used in the fluorescent light emitting layer 16 is not particularly limited, but a binder resin that does not absorb in the absorption region of the optically active rare earth complex and the fluorescent light emitting region is desirable. For example, the binder resin described above is used. it can.

  The protective layer 17 is not necessarily provided because it does not participate in the function as an identification mark, but it is desirable to provide the protective layer 17 to ensure the durability of the identification mark. The protective layer 17 is preferably made of a material that does not absorb in the excitation wavelength region and the fluorescence emission wavelength region of the optically active rare earth complex already described. For example, the binder resin already described can be used.

  When providing the identification mark on the article using the identification mark forming label, the adhesive adhesive layer 18 of the identification mark forming label is pressure-bonded to a predetermined portion of the article 14 at room temperature, and preferably about 120 ° C. Heat and pressurize at a temperature of 1 to strengthen the bond. Therefore, the pressure-sensitive adhesive layer 18 is desirably a pressure-sensitive pressure-sensitive adhesive having excellent adhesive strength both at the time of pressure bonding at normal temperature and after heating and pressing.

  Examples of the resin used for the adhesive adhesive layer 18 include a copolymer of alkyl acrylate and (meth) acrylic acid, a copolymer of alkyl acrylate and (meth) acrylic acid and vinyl acetate, and chloride. Vinyl chloride vinyl resins such as copolymers of vinyl and vinyl acetate, or copolymers added with vinyl alcohol, maleic anhydride or acrylic acid, polyester resins, acrylic resins, polyimide resins, polyurethane resins, phenol resins Etc.

  Furthermore, by adding a cross-linking agent to the resin composition, it is possible to control the adhesive strength at the time of room temperature pressure bonding and the adhesive strength after heating. As this crosslinking agent, those conventionally used for pressure-sensitive adhesives can be used, and specific examples include isocyanate-based crosslinking agents, amine-based crosslinking agents, and epoxy-based crosslinking agents.

The pressure-sensitive adhesive layer coating that can be used for the adhesive adhesive layer 18 is prepared by dissolving a resin exhibiting pressure-sensitive adhesiveness in a solvent, mixing and stirring.
For the application of the adhesive adhesive layer 18 and the fluorescent light emitting layer 16, a publicly known and publicly available coating method can be used.

Moreover, it is also possible to make the function of a pressure-sensitive adhesive layer and the function of a fluorescent light-emitting layer compatible in the same layer by containing the optically active rare earth complex in the pressure-sensitive adhesive layer 18.

The authenticity of the identification mark is determined by, for example, the system shown in FIG.
The excitation light source 1 serves as an excitation source for the fluorescent material and irradiates excitation light having a wavelength corresponding to the absorption wavelength of the fluorescent material. The identification mark is invisible under visible light, and emitting visible light upon irradiation with excitation light having a specific wavelength is desired as an identification mark for preventing counterfeiting. From this point of view, excitation emitted from the excitation light source 1 The wavelength of light is preferably in the ultraviolet region. Therefore, as the excitation light source 1, an ultraviolet light emitting object such as an ultraviolet LED, a black light, a xenon lamp, or a short wavelength semiconductor laser is used.

  The identification mark 2 is an identification mark that can emit fluorescence with excitation light having a specific wavelength irradiated from an excitation light source. The identification mark 2 of the present invention is an identification mark that can emit fluorescence having different intensities of the right circularly polarized component and the left circularly polarized component by the excitation light of a specific wavelength irradiated from the excitation light source.

  The lens system 3 effectively collects the light emitted from the identification mark 2 and then guides fluorescence to the wavelength selection unit 4 as parallel light by the collimator lens system.

  The wavelength selection unit 4 is provided for the purpose of extracting only the fluorescence having an arbitrary wavelength from the fluorescence emitted from the identification mark 2. As the wavelength selection unit 4, for example, a wavelength selection filter or the like can be used. Usually, in fluorescence emission, fluorescence of various wavelengths is emitted simultaneously. In order to improve the accuracy of true / false judgment, the wavelength selection filter has the largest difference in fluorescence intensity between the right circular polarization component and the left circular polarization component of the fluorescence compared to the total fluorescence emission intensity in the wavelength selection region. It is desirable to select a wavelength selective filter that extracts radiation of wavelengths.

  The circularly polarized light splitting unit 5 is used for the purpose of extracting only one of the right circularly polarized light component and the left circularly polarized light component included in the fluorescence. For example, by using a circularly polarizing plate, only one of the circularly polarized light components can be extracted. A circularly polarizing plate is usually composed of a quarter-wave plate and a linear polarizing plate. By making the optical axis direction of the quarter-wave plate and the optical axis direction of the linear polarizing plate a specific relationship, A right circularly polarizing plate that transmits only the circularly polarized light component and a left circularly polarizing plate that transmits only the left circularly polarized light component can be created. Therefore, it is possible to extract only the right circularly polarized component or only the left circularly polarized component of the fluorescence by switching the relative optical axis directions of the quarter wavelength plate and the linearly polarizing plate. Alternatively, it is possible to extract only the right circularly polarized light component or only the left circularly polarized light component by creating a right circularly polarizing plate and a left circularly polarizing plate, respectively, and switching them. Further, by using a two-divided left and right circularly polarizing plate, a four-divided left and right circularly polarizing plate, etc., the fluorescence emission can be separated and extracted into left and right circularly polarized components according to the incident surface.

  The light detection unit 7 is used to measure the intensity of each of the right circular polarization component and the left circular polarization component of the fluorescence divided by the circular polarization division unit 5. As the photodetector, a photodiode, a photomultiplier tube, a CCD, or the like can be used.

  The calculation unit 9 is a part that compares the intensity of the right circular polarization component of the fluorescence measured by the light detection unit 7 with the intensity of the left circular polarization component.

  Further, when the fluorescence emission is weak, in order to increase the detection sensitivity, the light modulation unit 6, the lock-in amplifier 8, and the like can be provided in the above system.

  The light modulator 6 includes an optical chopper, a photoelastic modulator, an optical phase modulation element using a nematic liquid crystal, a magneto-optic effect (Faraday cell) light modulation element, an electro-optic effect light modulation element, a pumping light from a semiconductor laser or LED. Although a modulator etc. can be utilized, it is not limited to this.

  The method described above merely describes the concept of the system, and the authenticity determination system is not limited to this.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Moreover, a part represents a mass part below.

(Synthesis of optically active rare earth complex 1)
2.00 parts of (S) -BINAPO represented by the following formula (10), 2.60 parts of europium-thenoyltrifluoroacetonate complex represented by the following formula (11), and 75 parts of methanol were stirred at room temperature for 2 hours. And reacted. After completion of the reaction, the solvent was distilled off with an evaporator to obtain a light yellow powder. This was recrystallized from ethanol to obtain 2.91 parts of a rare earth complex represented by the following formula (12) (S-Λ body; hereinafter referred to as S-Λ rare earth complex (12)).

It was confirmed that the rare earth complex represented by the formula (12) was generated by the following method.
¹ H NMR (d ₆ -acetone) δ 5.12 (s), 6.44 (s), 6.71 (t), 6.89 (t), 7.18 (q), 7.23 (t ), 7.30 (t), 7.63 (t), 7.76 (t), 7.89 (m), 8.05 (m), 8.31 (t)
³¹ P NMR (d ₆ -acetone) δ −67.47 (s)
Elemental analysis Measured value C57.19% H3.71% Eu10.4%
Calculated value C55.55% H3.02% Eu10.3%

(Synthesis of optically active rare earth complex 2)
1.98 parts of (S) -BINAPO, 2.56 parts of europium-benzoyltrifluoroacetonate complex represented by the following formula (13), and 70 parts of methanol were reacted at room temperature for 2 hours with stirring. After completion of the reaction, the solvent was distilled off with an evaporator to obtain a light yellow powder. This was recrystallized from ethanol to obtain 2.12 parts of a rare earth complex represented by the following formula (14) (S-Λ form; hereinafter referred to as S-Λ rare earth complex (14)).

It was confirmed that the rare earth complex represented by the formula (14) was generated by the following method.
¹ H NMR (d ₆ -acetone) δ 5.56 (s), 6.42 (s), 6.91 (t), 7.13 (m), 7.25 (d), 7.36 (t ), 7.64 (s), 7.75 (t), 7.93 (m), 7.99-8.14 (m)
³¹ P NMR (d ₆ -acetone) δ −62.55 (s)
Elemental analysis Measured value C60.92% H3.96% Eu10.3%
Calculated C61.21% H3.47% Eu10.5%

[Example 1]
A polyethylene terephthalate film having a thickness of 24 μm was used as the support film, and a fluorescent light-emitting layer having a dry thickness of 5 μm was provided on one side of the film using the composition a shown below.
a Composition for fluorescent light emitting layer
S-Λ rare earth complex (12) 5
Acrylic resin 5
(Mitsubishi Rayon “BR-85”)
Methyl ethyl ketone 20
Toluene 20
Cyclohexanone 10
Next, a protective layer having a dry thickness of 1 μm was provided on the fluorescent light emitting layer using the composition b shown below.
b Composition for protective layer
Vinyl chloride-vinyl acetate copolymer 8
(Union Carbide “VAGH”)
Polyurethane resin 2
("TS-03" manufactured by Dainippon Ink & Chemicals, Inc.)
Methyl ethyl ketone 45
Toluene 45

Further, on the side of the support film opposite to the side on which the fluorescent light emitting layer is provided, the following adhesive composition c is used to form a pressure-sensitive adhesive layer so as to have a dry thickness of 30 μm, and then this pressure-sensitive adhesive layer The release paper was pasted so that it touched. Then, the obtained film was punched into a predetermined shape to produce an identification mark forming label.
c Composition for adhesive adhesive layer
Alkylphenol resin 6
("TAMANOL 100S" manufactured by Arakawa Chemical Industries)
Acrylic ester / acrylic acid / vinyl acetate copolymer 67
("Cybinol SD-102" manufactured by Seiden Chemical Industry Co., Ltd.)
Toluene 26
Isocyanate curing agent 1
(Nippon Polyurethane “Coronate L”)

[Example 2]
In Example 1, an identification mark forming label was obtained by using the S-Λ rare earth complex (14) instead of the S-Λ rare earth complex (12).

[Comparative Example 1]
In Example 1, an identification mark forming label was obtained by using the following fluorescent material d instead of the S-Λ rare earth complex (12).
d Fluorescent material (Lumicolor manufactured by Seishin Enterprise)

(Test items and results)
Using the identification mark forming labels of Example 1, Example 2, and Comparative Example 1, identification marks were formed on Kent paper. Regarding these fluorescent light emitting layers, circularly polarized light emission characteristics were measured using CPL-200 manufactured by JASCO Corporation.

(Fluorescence emission and CPL)
6 to 8 show fluorescence emission spectra of Example 1, Example 2, and Comparative Example 1. FIG. Example 1, Example 2, and Comparative Example 1 showed very similar fluorescence spectra, and the difference in these luminescences could not be distinguished by visual observation.

  9 to 11 show CPL spectra of Example 1, Example 2, and Comparative Example 1. FIG. The CPL spectrum shows non-equilibrium between the right circular polarization component and the left circular polarization component of fluorescence, and the intensity of the right circular polarization component of fluorescence differs from that of the left circular polarization component as this value departs from 0. It is shown that. In Examples 1 and 2, there is a clear peak corresponding to light emission near 590 nm, whereas in Comparative Example 1, no peak was observed.

(G value)
The g value in the emitted light having a wavelength of 590 nm was −0.04 in Example 1 and −0.05 in Example 2, whereas 0.01 in Comparative Example 1.

(Use as identification mark)
From the above results, the identification mark disclosed in this patent could be determined using the g value in the emitted light of 590 nm. That is, an absolute value 0.03 is set as the threshold value of the g value, an identification mark indicating a g value having a larger absolute value than that is “positive”, and an identification mark indicating a g value having a smaller absolute value is “false”. By doing so, it was possible to discriminate between the identification mark disclosed in this patent and the identification mark using another fluorescent material.

It is a section lineblock diagram of transfer foil for identification mark formation of the present invention. It is a cross-sectional block diagram of the article | item which provided the identification mark using the transfer foil for identification mark formation of this invention. It is a cross-sectional block diagram of the identification mark formation label of this invention. It is a cross-sectional block diagram of the article | item provided with the identification mark using the label for identification mark formation of this invention. It is a conceptual diagram of the discrimination | determination system of the identification mark of this invention. 2 is a fluorescence emission spectrum of Example 1. 2 is a fluorescence emission spectrum of Example 2. 2 is a fluorescence emission spectrum of Comparative Example 1. 2 is a CPL spectrum of Example 1. 2 is a CPL spectrum of Example 2. 2 is a CPL spectrum of Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excitation light source 2 Identification mark 3 Lens system 4 Wavelength selection part 5 Circular polarization split part 6 Light modulation part 7 Photodetection part 8 Lock-in amplifier 9 Calculation part 10 Temporary support film 11 Protective layer 12 Fluorescence emission layer 13 Adhesive layer 14 Article 15 Support film 16 Fluorescent light emitting layer 17 Protective layer 18 Adhesive adhesive layer 19 Release paper

Claims (12)

In an identification mark having a fluorescent light-emitting layer containing a rare earth complex, the rare earth complex has the general formula (1)

(Wherein, X1 and X2 each independently represent any one of a group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxyl group having 1 to 4 carbon atoms; Y2, Y3 and Y4 each independently represent a hydrogen atom, a halogen atom, and represented by any one represents one) of the group consisting of alkyl group having 1 to 4 carbon atoms, a bidentate R or S Contains one phosphine oxide ligand and has the general formula (4)

A pyrazolone ligand represented by the general formula (5)

A quinolinol ligand represented by the general formula (6)

A bissulfonylamide ligand represented by the general formula (7)

Β-diketone ligand represented by the formula (in the general formulas (4) to (7), R3, R4 and R5 are each independently an alkyl group having 1 to 20 carbon atoms, or a fluorine-substituted one having 1 to 20 carbon atoms) Alkyl group, hydroxyl group, nitro group, amino group, cyano group, mercapto group, alkylsulfonyl group having 1 to 4 carbon atoms, alkylthio group and alkylsilyl group, phenylsulfonyl group which may have a substituent, phenylthio group and phenyl Represents any one of the group consisting of a silyl group, an aryl group, and a heteroaryl group.)
An optically active rare earth complex of Δ-form containing one or two or more ligands selected from the group consisting of and coordinated with the R-form of the ligand represented by the general formula (1), or An identification mark, which is a Λ-form optically active rare earth complex in which the S form of the ligand represented by the formula (1) is coordinated . The optically active rare earth complex contains two types of ligands: a ligand represented by the general formula (1) and a ligand having a β-diketone structure represented by the general formula (7). The identification mark according to claim 1, which is an optically active rare earth complex. The optically active rare earth complex is represented by the following general formula (2)

(In the formula, X1, X2, Y1, Y2, Y3 and Y4 represent the same meaning as in the general formula (1), and R1 and R2 are each independently an alkyl group having 1 to 20 carbon atoms and 1 to 20 carbon atoms. Fluorine-substituted alkyl group, hydroxyl group, nitro group, amino group, cyano group, mercapto group, alkylsulfonyl group having 1 to 4 carbon atoms, alkylthio group having 1 to 4 carbon atoms, alkylsilyl group having 1 to 4 carbon atoms, phenyl A sulfonyl group, a phenylthio group, a phenylsilyl group, a cyclopentadienyl group (one CH2 group present in the group may also be replaced by -O- or -S-), a phenyl group (in the group 1 or 2 CH groups present in may also be replaced by N), or a naphthyl group (1 or 2 CH groups present in the group may also be replaced by N The phenylsulfonyl group, phenylthio group, phenylsilyl group, cyclopentadiene group, phenyl group, and naphthyl group may be unsubstituted or substituted with one or more halogen atoms. The identification mark according to claim 2, which is an optically active rare earth complex represented by: an atom or an alkyl group having 1 to 4 carbon atoms, wherein Ln represents a rare earth metal atom. The identification mark according to claim 3, wherein X1 and X2 in the general formula (2) are hydrogen atoms. The identification mark according to claim 3 or 4 , wherein Y1, Y2, Y3 and Y4 in the general formula (2) are hydrogen atoms. The identification mark according to any one of claims 3 to 5, wherein Ln in the general formula (2) is Eu. The identification mark according to any one of claims 3 to 6, wherein R1 in the general formula (2) is a trifluoromethyl group. The identification mark according to any one of claims 3 to 7, wherein R2 in the general formula (2) is a thienyl group. The identification mark according to any one of claims 3 to 8, wherein the optical purity of the compound represented by the general formula (2) is 90% or more. The identification mark according to claim 1, wherein the identification mark comprises a fluorescent light emitting layer containing at least an optically active rare earth complex, and an adhesive layer. A transfer foil used for providing the identification mark according to claim 10, wherein a fluorescent light emitting layer containing an optically active rare earth complex and an adhesive layer are laminated in this order on a temporary support film. Transfer foil. A label used for providing the identification mark according to claim 10, comprising a fluorescent light-emitting layer containing an optically active rare earth complex on one side on a support film, and an adhesive layer on the other side. A label characterized by having.

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