JP2008115225A - Luminescent ink and use of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a red-colored luminescent ink capable of showing a sufficient and stable luminescent intensity under an ultraviolet light radiation and a high solubility with resins and organic solvents. <P>SOLUTION: This luminescent ink contains at least a luminescent compound expressed by formula (1) and a liquid medium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a luminescent ink used for security applications for the purpose of preventing counterfeiting, and a luminescent ink used for manufacturing a luminescent element containing a luminescent material in the EL field and LED field, and the application thereof.

  In recent years, the term functional organic compound has come to be used, and research on the use of functional compounds in electronic and optical devices has become active. As a functional organic compound, for example, a light emitting compound having a photoluminescence (PL) phenomenon is known. Here, photoluminescence means that fluorescence or phosphorescence is generated by stimulation of ultraviolet rays, visible light, or infrared rays. As such a light-emitting compound, a rare earth complex of β-diketone having high light emission luminance has attracted attention.

  When preparing a light emitting layer containing a light emitting compound, it is necessary to securely fix the light emitting compound to a desired portion of a material such as a substrate, paper, film, or element. In general, an ink composition containing a light emitting compound is used to prepare a light emitting layer containing a light emitting compound. A uniform thin layer can be prepared by applying or coating an ink composition containing a light emitting compound. Moreover, the printed matter or printed matter which has a luminescent image can be created by using the ink composition containing a luminescent compound. Attempts have been made to use an ink composition containing a light-emitting compound by a method suitable for various applications.

  For example, in Japanese Unexamined Patent Publication No. 2000-160083 (Patent Document 1), the content of 4,4,4-trifluoro-1- (2-thienyl) -1,3-butanedionate europium chelate compound as a luminescent material Is an ink composition for ink jet printing containing 0.001 to 5% by weight of an alcohol solvent as a solvent. Further, JP-A-2005-112947 (Patent Document 2) proposes a printed matter comprising a printing ink containing an optically active rare earth complex which is a diketone phosphine oxide complex and a printing layer comprising the printing ink. ing. JP-A-2001-354953 (Patent Document 3) proposes an ink composition containing a europium complex of a diketone having triphenylphosphine oxide as a ligand and a red fluorescent material. These inks are security inks (or anti-counterfeit inks). Images and / or characters formed using these inks are not visible under visible light, but when irradiated with ultraviolet light (for example, a black light lamp), these images emit light and are visible. Thus, the recorded image and the recorded information can be read.

  Furthermore, in Japanese Patent Application Laid-Open No. 2003-81989 (Patent Document 4), a rare earth complex for an optical functional material, which is a rare earth complex of a diketone having triphenylphosphine oxide as a ligand, is included in a transparent solid support. Optical functional materials and light emitting devices using combinations of these materials with LEDs or semiconductor lasers have been proposed. JP-A-2005-44930 (Patent Document 5) contains a rare earth complex having a β-diketone as a skeleton and phenanthroline as a ligand, and at least part of hydrogen atoms are substituted with fluorine atoms. Proposed ink and LED element for light emitting layer formation of LED element in which polymer is dissolved or dispersed in fluorine-substituted solvent in which part of hydrogen atom is substituted with fluorine atom and fluorine non-substituted solvent not containing fluorine atom Has been. These inventions relate to an LED element using an organic phosphor as a β-diketone rare earth complex.

  In JP-A-11-199865 (Patent Document 6), in an organic EL device comprising at least an anode, an organic hole transport layer, an organic light emitting layer and a cathode, a europium complex containing methylthiophene as an organic light emitting layer or There has been proposed an organic EL element including a layer doped with the derivative. Japanese Patent Application Laid-Open No. 10-158639 (Patent Document 7) proposes an electroluminescence element using a europium complex of β-diketone. In these, an organic phosphor of a β-diketone rare earth complex is used for a light emitting layer of an EL element.

  Such a light emitting compound or ink composition is not yet sufficient in light emission intensity for the above-mentioned use, and a light emitting compound or ink composition having higher light emission intensity is required. In addition, the light emitting compound has a problem of poor solubility in a solvent and dispersibility in a resin. Ink compositions generally contain a solvent and the ink components need to be stably dissolved or dispersed in this solvent. As this solvent, it is desired to use a highly safe alcohol solvent. Therefore, it is excellent in luminescence intensity, can not be substantially visually recognized under visible light, and can form a recorded image clearly visible under ultraviolet irradiation, and can be dissolved in a solvent, particularly an alcohol solvent. Development of a luminescent ink having good stability is desired.

JP 2000-160083 A JP 2005-112947 A JP 2001-354953 A Japanese Patent Laid-Open No. 2003-81989 JP 2005-44930 A JP-A-11-199865 Japanese Patent Laid-Open No. 10-158639

  The present invention has been made in view of the above-mentioned problems, and its first purpose is that it cannot be substantially visually recognized under visible light, and can be clearly visually recognized under ultraviolet irradiation. To provide a luminescent ink that can form a recorded image that can be detected with high sensitivity under ultraviolet irradiation without being affected by the color of the background, is safe for the human body, and is excellent in storage stability. is there.

  The second object of the present invention is to provide an LED element light emitting layer forming ink having excellent light emitting characteristics, excellent dissolution stability and coating suitability, and high heat resistance. The third object of the present invention is to provide an LED element which is prepared by using the above LED element light emitting layer forming ink and has excellent element characteristics such as luminous efficiency, heat resistance and durability. There is.

  Further, the fourth object of the present invention is a number, character, color, pattern, symbol, code, barcode, etc. that cannot be substantially visually recognized under visible light and can be clearly recognized under ultraviolet irradiation. Can be recorded on paper such as banknotes, securities, insurance cards, ID cards, documents, cards such as wood, plastic, metal, IC, and other articles, and security containing the above luminescent ink It is to provide an ink composition for use.

  The fifth object of the present invention is to provide an anti-counterfeit printed matter printed using the above-described ink composition for security use.

  The present invention provides a luminescent ink containing at least a luminescent compound represented by the following formula (1) and a liquid medium, whereby the above object is achieved.

[Wherein, R ¹ is a perfluoroalkyl group having 2 to 20 carbon atoms, and L ¹ and L ² are a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, and an arylalkyl group, respectively. Group or a perfluoroalkyl group provided that L ¹ and L ² are not the same phosphine oxide. ]

R ¹ in the above formula (1) is more preferably a linear perfluoroalkyl group having 2 to 3 carbon atoms.

In the above formula (1), L ¹ and L ² are phosphine oxides each composed of a branched or straight chain alkyl group or aryl group, provided that L ¹ and L ² are not the same phosphine oxide. More preferably, this is a condition.

  The present invention is also a luminescent ink containing at least a luminescent compound and a liquid medium, wherein the luminescent compound is a diketone compound represented by the following formula (3), a trivalent europium salt, and two phosphine oxide derivatives. Also provided is a luminescent ink, which is a europium complex obtained by a reaction of mixing.

[Wherein, R ¹ is a perfluoroalkyl group having 2 to 20 carbon atoms. ]

  More preferably, the liquid medium is an alcohol solvent, an ester solvent or an aromatic solvent.

  The present invention also provides an ink composition for security use, which contains at least the luminescent ink.

  The present invention also provides an anti-counterfeit printed matter obtained by using the above ink composition for security use.

  The present invention further provides a method for producing an anti-counterfeit printed matter including a step of printing using an ink composition for security use containing at least the luminescent ink.

  This invention also provides the ink composition for LED element light emitting layer formation containing the said luminescent ink at least.

  The ink composition for forming a light emitting layer of the LED element preferably further contains a water repellent polymer.

  The water repellent polymer is preferably a fluorine-based polymer.

  The present invention further provides a method for producing an LED element, comprising a step of forming a light emitting layer of an LED using the above-described ink composition for forming a light emitting layer of an LED.

  The present invention further provides an LED element obtained using the above-described ink composition for forming a light emitting layer of an LED element.

  In the LED element, it is preferable that at least one inorganic phosphor that emits yellow, green, or blue light and the light emitting compound are contained in the fluorescent layer.

  The luminescent ink of the present invention is characterized in that it does not develop color under visible light, but emits red light when irradiated with ultraviolet rays. The luminescent ink of the present invention has higher sensitivity in color development sensitivity by irradiation with ultraviolet rays than the conventional luminescent ink, and has higher luminescence intensity. The luminescent ink of the present invention is further characterized by little decrease in the amount of luminescence even after storage at high temperature, and excellent stability over time and storage stability.

  Furthermore, according to the present invention, an ink composition for security use containing at least the above-mentioned luminescent ink can be provided. A recorded image prepared using this ink composition for security use does not develop color under visible light, but emits red light when irradiated with ultraviolet rays. Due to this characteristic, it is difficult to see the difference from the recorded image with ordinary ink under visible light, and the difference from the recorded image with ordinary ink can be easily recognized visually when detected by ultraviolet irradiation. Yes. The ink composition for security use of the present invention can be used as an ink for printing recorded information that prevents fraud such as forgery and tampering. In addition, it is possible to easily determine visually whether or not the document has been forged by copying or the like by pressing a letter / pattern of a stamp using an ink composition for security purposes on a part of the document. I can do it.

  The luminescent ink of the present invention further has an advantage of excellent light resistance. The ink composition for security use containing at least the luminescent ink of the present invention is useful as an ink for preventing forgery or falsification of documents such as certificates, securities, and checks. By using the luminescent ink of the present invention, it is possible to provide an ink composition for security use having excellent solubility and emission luminance, and excellent temporal stability.

  The present invention can also provide an ink for forming a light emitting layer of an LED element that has good light emission characteristics, is excellent in dissolution stability and coating suitability, and has high heat resistance. Furthermore, the LED element excellent in color purity, color rendering property, and durability can be provided by forming a light emitting layer using this ink composition for LED element light emitting layer formation.

  The luminescent ink of the present invention is characterized by containing at least a luminescent compound represented by the following formula (1) and a liquid medium.

In Formula (1), R ¹ is a C 2-20 perfluoroalkyl group, and L ¹ and L ² are each a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, It is a phosphine oxide composed of an arylalkyl group or a perfluoroalkyl group, and these groups may or may not have a substituent. And in the present invention, L ¹ and L ² in Formula (1) is provided that is not identical phosphine oxide.

  More specifically, the light-emitting compound represented by the formula (1) can be represented by the following formula (2).

In formula (2), ^{R 1} are as defined as ^{R 1} of formula ^(1), R 2 ~R ⁷ are each branched or straight-chain alkyl group, branched or straight-chain alkenyl group, an aryl group, A phosphine oxide having an arylalkyl group or a perfluoroalkyl group, and these groups may have a substituent or may not have a substituent. In the formula (2), the phosphine oxide having R ^{2 to} R ⁴ corresponds to L ¹ in the formula (1), and the phosphine oxide having R ^{5 to} R ⁷ corresponds to L ² in the formula (1). And in the present invention. The condition is that the phosphine oxide having R ^{2 to} R ⁴ and the phosphine oxide having R ^{5 to} R ⁷ are not the same phosphine oxide.

R ¹ in Formula (1) and Formula (2) is a C 2-20 perfluoroalkyl group, and more specifically a C ₂ F ₅ -group, an nC ₃ F ₇ -group, i- C ₃ F ₇ - group, _n-C 4 _{F 9} - group, _i-C 4 _{F 9} - group, _sec-C 4 _{F 9} - _{group, n-C 5 F 11} - group, _{neo-C 5 F 11} - Group, nC ₆ F ₁₃ -group, nC ₇ F ₁₅ -group, nC ₈ F ₁₇ -group, 2-C ₈ F ₁₇ -group, nC ₉ F ₁₉ -group, n-C Examples thereof include ₁₀ F ₂₁ -group, nC ₁₂ F ₂₅ -group, and nC ₁₈ F ₃₇ -group. Among these, R ¹ is preferably a C 2-10 perfluoroalkyl group, more preferably a C 2-3 perfluoroalkyl group.

R ^{2 to} R ⁷ in Formula (2) are more preferably each a branched or straight chain alkyl group having 1 to 12 carbon atoms, a branched or straight chain C 2-12 alkenyl group, or carbon number. It is a phosphine oxide having a 6-12 aryl group, a C7-12 arylalkyl group or a C1-6 perfluoroalkyl group, and these groups may have a substituent. You don't have to.
Examples of alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, n-pentyl, neo-pentyl, n- Examples include hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, lauryl group, stearyl group and the like.
Examples of the alkenyl group include a 1-propenyl group, a 2-propenyl group, a 1-methylethenyl group, a 3-butenyl group, and a 1-methyl-2-propenyl group.
Examples of the aryl group include a phenyl group, a tolyl group, a naphthyl group, and an anthranyl group.
Examples of the arylalkyl group include a benzyl group, α, α-dimethylbenzyl group and the like.
Examples of the substituent that these groups may have include, for example, halogen groups such as F, Cl, Br, and I; nitro groups; cyano groups; lower alkyl groups such as methyl groups, ethyl groups, propyl groups, and butyl groups. Group: lower alkoxy group such as methoxy group, ethoxy group, propoxy group, butoxy group; aryl group such as phenyl group, naphthyl group, phenethyl group; arylalkyl group such as benzyl group, α, α-dimethylbenzyl group; amino group Alkylamino group; dialkylamino group; and the like.

  As shown in the above formula (1), the light-emitting compound used in the present invention comprises three molecules of a specific β-diketone derivative having a 2-naphthyl group bonded to trivalent europium, and two different types of phosphine oxides. Each compound is coordinated by one molecule. This luminescent compound is an ultraviolet-excited europium complex and has a property of emitting red light when irradiated with ultraviolet rays.

In the present invention, by limiting the luminescent compound contained in the luminescent ink to the europium complex represented by the formula (1), the emission intensity is improved and the solubility in a liquid medium and the stability over time are improved. It has been found to have a great effect. The luminescent compound of the present invention is a europium complex in which a β-diketone having a naphthyl group and a perfluoroalkyl group (R ¹ ) having 2 or more carbon atoms is coordinated as shown in Formula (1), By having the system ligand, the above-described excellent effect is obtained. Further, in the present invention, it has been found that when the number of carbon atoms of the perfluoroalkyl group represented by R ¹ is 2 or more, there is a greater improvement effect than when the number of carbon atoms is 1.

As a more preferable light-emitting compound, R ¹ in the above formula (1) is a perfluoroalkyl group having 2 to 3 carbon atoms, and L ¹ and L ² are each composed of a branched or straight chain alkyl group or aryl group. Phosphine oxides, provided that L ¹ and L ² are not the same phosphine oxide. The branched or straight-chain alkyl group or aryl group constituting L ¹ and L ² may have a substituent or may not have a substituent. As a more specific example of such a preferable luminescent compound, R ¹ in the above formula (2) is a perfluoroalkyl group having 2 to 3 carbon atoms, and R ^{2 to} R ⁴ are each branched or linear. The compound which is an alkyl group and R < ⁵ > -R < ⁷ > is an aryl group respectively is mentioned. R ^{2 to} R ⁷ may have a substituent or may not have a substituent. These luminescent compounds have higher luminescence intensity, and are more excellent in solubility in a liquid medium and stability over time.

The europium complex which is a luminescent compound in the present invention is obtained by a reaction of mixing a diketone compound represented by the following formula (3), a trivalent europium salt and two phosphine oxide derivatives. The light-emitting compound in the present invention can be synthesized using a known method. As an example of the synthesis of the luminescent compound, for example, the outline of the production process of the luminescent compound represented by the formula (2) is shown in the reaction formula (4). This reaction formula (4) is obtained by mixing and reacting a diketone compound represented by the following formula (3), a trivalent europium agent, and two phosphine oxide derivatives in one step. The process of obtaining the luminescent compound represented by this is shown. In this reaction formula (4), two types of phosphine oxide derivatives are represented by O = PR ² R ³ R ⁴ and O = PR ⁵ R ⁶ R ⁷ , where R ^{2 to} R ⁷ are as defined above. It is significant. In this specification, the synthesis method represented by the reaction formula (4) is referred to as a one-step reaction.

[In the formula, ^{R 1} is as defined as ^{R 1} of formula (1). ]

（４）

(4)

[In the formula, Eu-A is a trivalent europium agent, and R ¹ , R ^{2 to} R ⁴ , and R ^{5 to} R ⁷ represent R ¹ , R ^{2 to} R ^4, and R ^{5 to} R in the formula (2). ^This is equivalent to ⁷ . ]

  Examples of the trivalent europium agent represented by “Eu-A” in the reaction formula (4) include, for example, europium chloride, europium acetate, europium sulfate, europium hydroxide, europium alkoxide, and europium salts of organic acids. It is done. It is more preferable to use europium chloride as the trivalent europium agent.

  More specifically, the above one-step reaction is exemplified by a diketone compound represented by the formula (3), a trivalent europium agent, two phosphine oxide derivatives, and 1N-aq. For example, NaOH is used in a ratio of 3 mol, 1 mol, 2 mol (each 1 mol) and 3 mol, respectively, and mixed in a solvent such as an organic solvent at room temperature to 70 ° C., preferably 40 to 60 ° C. Thus, the light-emitting compound (europium complex) represented by the formula (2) can be obtained. Examples of organic solvents that can be used in the reaction include ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; alcohol solvents such as methanol, ethanol, and propanol; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, And glycol ether solvents such as diethylene glycol diethyl ether and propylene glycol monomethyl ether; and dimethyl sulfoxide, N-methyl-2-pyrrolidone, and γ-butyl lactone. The product thus obtained may be subjected to purification means such as crystallization or liquid-liquid extraction, if necessary.

As another example of the synthesis | combination of a luminescent compound, the outline of the other manufacturing process of the luminescent compound represented, for example by Formula (2) is shown in Reaction Formula (6). This reaction formula (6) is obtained by reacting a diketone compound represented by the following formula (3) with a trivalent europium agent to produce a europium complex represented by the formula (5); and the obtained formula The step of reacting the europium complex of (5) with two types of phosphine oxide derivatives simultaneously or sequentially to obtain a luminescent compound represented by formula (2) is shown. In this reaction formula (6), two types of phosphine oxide derivatives are represented by O = PR ² R ³ R ⁴ and O = PR ⁵ R ⁶ R ⁷ , where R ^{2 to} R ⁷ are as defined above. It is significant. In this specification, the synthesis method represented by the reaction formula (6) is referred to as a two-step reaction.

[In the formula, ^{R 1} is as defined as ^{R 1} of formula (1). ]

（６）

(6)

[In the formula, Eu-A is a trivalent europium agent, and R ¹ , R ^{2 to} R ⁴ , and R ^{5 to} R ⁷ represent R ¹ , R ^{2 to} R ^4, and R ^{5 to} R in the formula (2). ^This is equivalent to ⁷ . ]

  More specifically exemplifying the above two-step reaction, first, as the first step, a β-diketone derivative represented by the formula (3), a trivalent europium agent and 1N-aq. For example, by using NaOH at a ratio of 3 mol, 1 mol, and 3 mol, respectively, in a solvent such as an organic solvent, the mixture is heated and mixed at room temperature to 70 ° C, preferably 40 to 60 ° C. The europium complex represented can be obtained. As the organic solvent, those described above can be used.

  Next, the europium complex represented by the formula (5) and two types of phosphine oxide derivatives are used, for example, in a ratio of 1 mol and 2 mol (each 1 mol), respectively, in an organic solvent at room temperature to a solvent. The light-emitting compound (2) in the present invention can be produced by heating and mixing in the temperature range of the boiling point of, preferably 20 to 50 ° C. Examples of the solvent that can be used here include hydrocarbon solvents such as n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, and methylcyclohexane; halogenated hydrocarbon solvents such as dichloromethane, dichloroethane, and chloroform; Examples thereof include ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone. The product thus obtained may be subjected to purification means such as crystallization or liquid-liquid extraction, if necessary.

  Here, specific examples of the europium complex represented by the above formula (5) are shown below. The following examples illustrate the compounds specifically, but the present invention is not limited thereto.

  The luminescent compound of the present invention is synthesized by reacting two kinds of phosphine oxide derivatives as shown as the reaction of the above formula (4) or formula (6). Specific examples of two types of phosphine oxide derivatives that can be used in the present invention are shown in the following Table 2-1 and Table 2-2 using the following formula (7). The following examples illustrate the compounds specifically, but the present invention is not limited thereto.

  Specific examples of the light-emitting compound that can be used in the present invention are shown in Tables 3-1 and 3-2 below using Formula (2). The following examples illustrate the compounds specifically, but the present invention is not limited thereto.

The light emitting compound used in the present invention is characterized by high solubility in a liquid medium used for ink and good resin compatibility. This luminescent compound further has high luminescence intensity and is excellent in stability over time. The luminescent compound of the present invention is a europium complex in which a β-diketone having a naphthyl group and a perfluoroalkyl group (R ¹ ) having 2 or more carbon atoms is coordinated as shown in Formula (1), By having a system ligand, the solubility and light absorption intensity are further increased, the emission intensity is improved, the amorphousness is further increased, and the light emitting compound does not precipitate over time in the ink. It has become.

  The light emitting compound used in the present invention also has an advantage of being excellent in light resistance. This is considered to be derived from the fact that the light emitting compound in the present invention has an excellent property that the excitation energy quickly flows from the ligand to the europium.

Luminescent ink and ink for various applications Next, the luminescent ink of the present invention will be described. The luminescent ink of the present invention contains at least a liquid medium and a luminescent compound represented by the formula (1). The amount of the luminescent compound contained in the luminescent ink is preferably 0.001 to 20% by weight, more preferably 0.05 to 5% by weight, based on the total amount of the luminescent ink, More preferably, it is -3% by weight.

As a liquid medium used in the luminescent ink of the present invention,
Ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, 4-methoxy-4-methylpentanone:
Hydrocarbon solvents such as cyclohexane, methylcyclohexane, n-pentane, n-hexane and n-heptane:
Alcohol solvents such as methanol, ethanol, propanol, isopropanol:
Polyols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, dipropylene glycol, 1,2-hexanediol, 2,4,6-hexanetriol, dioxane, methyl cellosolve, ethyl cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, ethylene glycol mono Glycols such as butyl ether and ethylene glycol monoethyl ether and their ether solvents:
Ester solvents such as ethyl acetate, butyl acetate, and n-propyl acetate:
Halogen solvents such as 1,2-dichloroethane, dichloromethane, 1,1,2-trichloroethane, chloroform, etc .:
Examples include aromatic solvents such as toluene and xylene, and dimethyl sulfoxide: N-methyl-2-pyrrolidone, 2-pyrrolidone: γ-butyllactone: THF, and the like.

  Among these, ketone solvents such as acetone and methyl ethyl ketone, alcohol solvents such as methanol, ethanol and isopropanol, aromatic solvents such as toluene and xylene, ester solvents such as ethyl acetate, butyl acetate and n-propyl acetate, N -Methyl-2-pyrrolidone, dimethyl sulfoxide, ethylene glycol, etc. are recommended. Moreover, it is also possible to use a small amount of water in combination with the above solvent as a solvent. These solvents can be used alone or in combination.

  The luminescent compound contained in the luminescent ink of the present invention generally exhibits solubility or good dispersibility in the above various solvents and / or resins. Then, when the luminescent ink of the present invention is irradiated with ultraviolet rays, excitation of the luminescent compound occurs, whereby light emission in the red region (610 to 630 nm) occurs (for details, see Examples). For example, by irradiating the light emitting ink of the present invention with ultraviolet light (about 365 nm) from an ultraviolet lamp such as a black light lamp, the light emitting compound is excited, whereby light can be emitted in the red region. Therefore, the printed matter formed using the luminescent ink of the present invention has a feature that it does not emit light under visible light and emits red light under ultraviolet light.

  The luminescent ink of the present invention can be used for various applications. And by containing the luminescent ink of this invention, the ink composition for security uses, the ink composition for LED element light emitting layer formation, etc. can be prepared, for example. The amount of the luminescent compound contained in these various ink compositions for use is preferably 0.001 to 20% by weight, more preferably 0.05 to 5% by weight, based on the total amount of the luminescent ink. 0.1 to 3% by weight is more preferable.

  The luminescent ink and the ink composition for various uses of the present invention include ink for inkjet printing: printing ink for offset printing ink, gravure printing ink, silk screen, etc .: ink for thermal transfer printing: ink for writing instruments: ink for deposition: solution for vapor deposition: It can be applied to a solution for spin coating, a coating material for coating, and the like.

  By preparing the ink composition for security use containing the luminescent ink of the present invention, confidential information that cannot be visually recognized under visible light but can be visually recognized by using a specific means such as ultraviolet irradiation is printed. can do. Forgery of important printed materials (eg credit cards, cash cards, debit cards, gift certificates, securities, identification cards, banknotes, licenses, etc.) by providing ink compositions for security applications and such confidential information on printed materials , Alteration, tampering, etc. can be prevented. For example, the presence or absence of such confidential information is determined using a specific means such as ultraviolet irradiation, and a printed matter (article) provided with genuine confidential information is regarded as genuine, and a printed matter (article) other than that is regarded as counterfeit. Judgment can be made.

  Moreover, the ink composition for LED element light emitting layer formation using the luminescent ink of this invention has the advantage that formation of the LED element light emitting layer using an inkjet recording system can be performed favorably.

  Ink jet recording is a recording method in which printing is performed by causing droplets of an ink composition to fly and adhere to a recording medium such as paper. This ink jet recording has a feature that high-resolution and high-quality images can be printed at high speed. Further, in recent years, ink jet recording has attracted attention and has been put into practical use not only in paper but also in the formation of electric circuits and semiconductor substrates. The luminescent ink of the present invention is suitable for inkjet recording applications because the luminescent compound has high solubility and is stable.

  In addition, by coating the ink composition for forming the LED element light emitting layer obtained from the light emitting ink on the element using an inkjet recording method, the amount of the light emitting compound can be reduced even if the amount of the light emitting compound is very small. It becomes easy to control evenly. Therefore, color unevenness on the light emitting surface and variations among light emitting elements can be extremely reduced. Further, the ink jet recording method has an advantage that an appropriate amount of a light emitting compound can be selectively applied to a desired place any number of times. Therefore, a desired light-emitting element can be formed with high productivity.

  As a method for forming a thin film of a light emitting layer of a light emitting element, a physical vapor deposition method (PVD method), a chemical vapor deposition method (CVD method) or the like is generally used in addition to an ink jet recording method. Is usually used. The vacuum deposition method is a method of forming a thin film by heating and evaporating a light emitting element forming ink containing a light emitting compound in a vacuum and attaching it to a substrate (for example, between two electrode layers). . The luminescent ink of the present invention can also be used in such a vacuum deposition method. Furthermore, the ink composition for LED element light emitting layer formation of this invention can also be apply | coated by a spin coat method, and it can also be made to adhere to a thin film form.

  The luminescent ink of the present invention may further contain various additives. Examples of additives include binders (resins), penetrants, antifoaming agents, colorants, antioxidants, UV absorbers, lubricants, antiseptics, antifungal agents, rust inhibitors, dispersants, rheology control agents, Various additives such as surfactants, pH adjusters, film modifiers, charge control agents (charge control agents), oils and fats such as animal and vegetable oils, and the like are appropriately selected as necessary. Can be used. One or more additives suitable for various application ink compositions can be used as necessary.

  The binder (resin) component is used for the purpose of satisfactorily fixing the light emitting material, forming a thin film layer of the light emitting layer, stabilizing the ink, and adjusting the viscosity. A known resin can be suitably used as long as it dissolves in the liquid medium.

Specific examples of the binder (resin) component include polyvinyl resins such as polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, and vinyl pyrrolidone-vinyl acetate copolymer:
Polyamine resins such as polyallylamine, polyvinylamine, and polyethyleneimine:
Polyacrylate resins such as polymethyl acrylate, polyethylene acrylate, polymethyl acrylate, polymethyl methacrylate, and polyvinyl methacrylate:
Rosin, rosin modified resins (phenol, maleic acid, fumaric acid resin, etc.):
Cellulosic resins such as ethyl cellulose and nitrocellulose:
Polyolefin resins such as polyethylene resin and polypropylene resin:
Phenol-modified xylene resin: xylene resin: terpene phenol resin: phenol resin: ketone resin: acrylic resin: styrene-acrylic resin: styrene-maleic resin: terpene resin: terpene-maleic resin: polystyrene resin: polyurethane resin: acrylic urethane Resin: Polyester resin: Vinyl chloride resin: Vinylidene chloride resin: Polyvinyl formal and copolymers thereof: Alkyd resin: Epoxy resin: Polyester imide resin: Polyamide resin: Polyamide imide resin: Silicone resin: Fluorine resin (Fluorine resin) Polymer): natural resin type (gum arabic, gelatin, etc.) and the like. One or more of the resins listed above can be used.

  In writing instrument ink, ink jet printing ink, or printing ink application, it is preferable to use polyvinyl resin, polyacrylate resin, polyamine resin, or the like.

  In the case of preparing a cured film or a cured layer using the luminescent ink of the present invention, as a binder (resin) component, ultraviolet curable, visible light curable, infrared curable, electron beam curable, oxidation curing. , Thermosetting or moisture curable resin compositions are preferably used together. Among these, it is more preferable to use an ultraviolet curable resin composition.

  When a binder (resin) component is contained in the luminescent ink, the content of these binder (resin) components is preferably 0.5 to 30% by weight in the ink composition, and is 1 to 10% by weight. Is more preferable. If it is less than 0.5% by weight, the light emitting material may not be sufficiently fixed to the non-permeable recording material. Moreover, when it exceeds 30 weight%, the dissolution stability of an ink composition may be reduced. In addition, the binder layer is thickly covered around the light emitting material, which may cause a decrease in light emission of the light emitting material. The use of a binder (resin) has an advantage that strong water resistance can be obtained in a recorded matter.

  Examples of pH adjusters include amine compounds such as diethylamine, triethanolamine, and triethylenetetramine, as well as amide compounds, hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and carbonates. .

  Examples of the surfactant include anionic, nonionic, cationic and amphoteric surfactants.

  Specific examples of the anionic surfactant include benzene sulfonic acid or a salt thereof which may have 0 to 2 alkyl groups or hydroxyl groups, an alkyl diphenyl ether sulfonic acid or a salt thereof, an α-olefin sulfonic acid or a salt thereof, Polystyrene sulfonic acid or salt thereof, alkyl sulfate ester or salt thereof, polyoxyethylene alkyl ether sulfate ester or salt thereof, or polyoxyethylene alkyl phenyl ether sulfate ester or salt thereof, alkyl ether phosphate ester salt, alkyl phosphate ester, etc. Anionic surfactants can be exemplified.

  Specific nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester Examples thereof include nonionic surfactants such as glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, fluorine-based and silicon-based. Specific examples of cationic surfactants include cationic surfactants such as lauryltrimethylammonium chloride and didecyldimethylammonium chloride.

  Examples of the film modifier include soybean lecithin, microsilica, and wax.

When the luminescent ink is for inkjet printing, a charge control agent can be included. Examples of the charge control agent for charge control type inkjet ink include lithium salts such as LiNO ₃ , potassium salts such as KCN and KSCN, quaternary ammonium salts, and cationic compounds such as tetraphenylphosphonium bromide.

  A colorant selected from known dyes and pigments can be added to the luminescent ink of the present invention within a desired range. Examples of the colorant include azo, azo-containing, azomethine, anthraquinone, anthrapyridone, quinacridone, dioxazine, diketopyrrolopyrrole, isoindolinone, indanthrone, perinone, and perylene. And organic dyes such as various dyes such as azoindigo, thioindigo, quinophthalone, quinoline, and triphenylmethane. By using these colorants, the hue of the luminescent ink may be matched with the hue of the base to be printed.

  The ink composition of the present invention, such as a luminescent ink, is prepared by mixing the above-mentioned luminescent compound, liquid medium, and binders, additives, etc. as necessary, stirring to dissolve, diluting as necessary, and It can be prepared by adding other additives accordingly. The mixing and stirring can be performed by a high-speed disperser, an emulsifier, or the like, in addition to stirring by a normal stirrer using a blade. The obtained luminescent ink can be filtered and purified before or after dilution, if necessary. When filtering, for example, it can be filtered with a filter having a pore size of 3.0 μm or less, preferably a filter having a pore size of 1.0 μm or less.

  The ink composition of the present invention selects various types of printers and various types by selecting the type of solvent, the presence / absence of use of a binder, the type, the amount, etc., and adjusting the viscosity, surface tension, conductivity, drying property, etc. It can be applied to a recording medium. For example, when an absorptive recording material such as paper is targeted, a light emitting compound, a liquid medium, and, if necessary, a binder component, an additive, and the like are dissolved and used.

  Below, the example of the specific aspect of the luminescent ink of this invention is described. The following examples specifically illustrate the ink, but the present invention is not limited to these.

(1) Embodiment 1 of Preferred Applications As a suitable example of an ink using an alcohol liquid medium, a luminescent ink using the above alcohol organic solvent or glycol and its ether organic solvent as a liquid medium can be mentioned. Such a luminescent ink is a highly safe and highly volatile ink. In this luminescent ink, for example, a luminescent compound is dissolved in an alcohol-based liquid medium (referred to as an alcohol-based organic solvent and / or glycol and its ether-based organic solvent), and is usually added to a binder resin, various surfactants, or the like as necessary. It can be prepared by mixing with the contained components. The alcohol-based liquid medium refers to a solvent containing alcohol or glycol ether as a main component. For example, a mixture of alcohol and water is contained in an alcohol-based liquid medium when it contains alcohol as a main component. Here, the main component means a component contained in the solvent in an amount of 60% by weight or more, preferably 80% by weight or more. Such a luminescent ink can be an ink adjusted so as to dissolve stably at a relatively high concentration that maximizes the luminescence intensity of the luminescent compound contained.

  When a mixture of alcohol and water is used as the alcoholic liquid medium, various surfactants (for example, anionic properties such as alkyl sulfates, phosphates, polyoxyethylene alkyl ethers, alkylamine salts, Nonionic, cationic surfactant, amphoteric surfactant, fluorosurfactant or acetylene glycol surfactant), dispersant (for example, rosin acid soap, stearic acid soap, oleic acid soap, Na -Di-β-naphthylmethane disulfate, Na-lauryl sulfate, Na-diethylhexylsulfosuccinate) or cyclodextrin (CD) (eg β-CD, dimethyl-β-CD, methyl-β-CD, hydroxy Ethyl-β-CD, hydroxypropyl-β-CD, etc.), defoaming It can be added and the like. When these additives are used, the content is preferably 0.1 to 5% by weight, more preferably 1 to 3% by weight, based on the ink composition.

  Such luminescent inks can be printed on the surface of various articles by methods such as marking with felt pens and ballpoint pens, inkjet printing using an ink jet printer, and brushing. Using the luminescent ink, it is possible to form a printed layer made of a desired mark such as a barcode, a hidden character of a document, a symbol, or a cardboard marking, and a printed matter can be manufactured. Although this printed matter cannot be visually recognized under visible light, it has a security function because it emits strong light when irradiated with light of a specific wavelength. This luminescent ink also uses an alcohol-based liquid medium that is highly safe for the human body, which reduces the burden on the environment and is safe to use even in offices without any restrictions. it can. Moreover, it is excellent in drying at the time of printing, and is excellent in printing workability.

(2) Embodiment 2 of Preferred Applications As an example of the use of the anti-counterfeit printed luminescent ink, an ink composition for security use (anti-counterfeit ink) using the luminescent ink can be mentioned. The light-emitting compound in the present invention has a property of emitting red light when irradiated with ultraviolet light using black light or the like. A printed matter can be prepared by dissolving or dispersing the luminescent compound in a printing ink and printing using the printing ink. Accordingly, the printed matter emits red fluorescence under ultraviolet light using black light or the like, and can be more clearly distinguished from fluorescence of a fluorescent brightener (blue light emission) contained in recycled paper or the like. This red light emission does not occur under visible light. As a result, it is possible to manufacture a printed material on which a forgery prevention measure that is easier to determine authenticity is applied. The printing method in producing such a forgery-preventing printed material is not particularly limited, and examples include gravure printing, flexographic printing, offset printing, screen printing, and inkjet printing. It is also possible to use printing ink as ink for a marking pen or the like. The ink composition for security use according to the present invention is a printed matter on which a forgery prevention measure has been applied, and can be suitably used particularly for the production of securities having a short life cycle such as gift certificates and admission tickets. In particular, it exhibits excellent practical effects in the preparation of printed matter that has been subjected to anti-counterfeiting measures that contribute to the reduction of environmental burden using recycled paper.

(3) Embodiment 3 of preferred use As an example of the use of the luminescent ink described in the LED element, an ink composition for forming a LED element luminescent layer using the luminescent ink may be mentioned. The ink composition for forming an LED element light emitting layer preferably contains a light emitting compound, a liquid medium and a water repellent polymer. As the water repellent polymer, it is preferable to use a fluorine-based polymer.

  When forming the fluorescent layer of the LED element using the ink composition for forming the LED element light emitting layer, the properties of the polymer that dissolves the europium complex that is the light emitting compound has a great influence on the light emitting characteristics and durability of the obtained LED element. Effect. As this polymer, a fluoropolymer is more desirable in terms of transparency and water repellency.

  The amount of the polymer contained in the LED element light emitting layer forming ink composition is in the range of 0.5 to 40% by weight, and preferably in the range of 1 to 30% by weight. When the concentration of the light emitting compound contained in the ink composition for forming the LED element light emitting layer is in the range of 10 to 80% by weight based on the polymer solid content, sufficient light emission intensity can be obtained. Examples of the fluorine-based polymer used in the present invention include those represented by the following formula. When using a fluorine-based polymer represented by the following formula, it is desirable to use ethyl acetate as the liquid medium.

(Wherein x, y and z are integers of 1 or more)

  The ink composition for LED element light emitting layer formation can be prepared similarly to luminescent ink. At the time of this preparation, it is desirable that the fluoropolymer is previously dissolved in the liquid medium.

  The ink composition for LED element light emitting layer formation of this invention may also contain other light emitting compounds other than the light emitting compound of this invention. Examples of other light-emitting compounds other than the light-emitting compound of the present invention include inorganic phosphors that emit yellow, green, or blue light.

  Examples of inorganic phosphors that emit yellow light include YAG: ε alkaline earth metal silicate phosphors.

Illustrating a specific wavelength range of fluorescence emitted by a phosphor emitting green fluorescence (hereinafter referred to as “green phosphor” as appropriate), the peak wavelength is usually 490 nm or more, preferably 500 nm or more, and usually 570 nm or less. Preferably, it is 550 nm or less. As such a green phosphor, for example, europium activation represented by (Mg, Ca, Sr, Ba) Si ₂ O ₂ N ₂ : Eu that is composed of fractured particles having a fracture surface and emits light in the green region. An alkaline earth silicon oxynitride phosphor, composed of fractured particles having a fractured surface, emits light in the green region (Ba, Ca, Sr, Mg) ₂ SiO ₄ : Europium activated alkaline earth represented by Eu Silicate phosphors and the like.

In addition, examples of the green phosphor include Eu-activated aluminate phosphors such as Sr ₄ Al ₁₄ O ₂₅ : Eu, (Ba, Sr, Ca) Al ₂ O ₄ : Eu, and (Sr, Ba) Al. _{2 Si 2 O 8: Eu,} (Ba, Mg) 2 SiO 4: Eu, (Ba, Sr, Ca, Mg) 2 SiO 4: Eu, (Ba, Sr, Ca) 2 (Mg, Zn) Si 2 O ₇ : Eu activated silicate phosphor such as Eu, Y ₂ SiO ₅ : Ce, Tb activated silicate phosphor such as Ce, Tb, Sr ₂ P ₂ O ₇ —Sr ₂ B ₂ O ₅ : Eu Eu-activated boric acid phosphor such as Sr ₂ Si ₃ O ₈ -2SrCl ₂ : Eu-activated halosilicate phosphor such as Eu, Zn ₂ SiO ₄ : Mn-activated silicate fluorescence such as Mn Body, CeMgAl ₁₁ O ₁₉ : Tb, Y ₃ Al ₅ O ₁₂ : Tb-activated aluminate phosphor such as Tb, Ca ₂ Y ₈ (SiO ₄ ) ₆ O ₂ : Tb, La ₃ Ga ₅ SiO ₁₄ : Tb-activated silicate phosphor such as Tb, (Sr, Ba , Ca) Ga ₂ S ₄ : Eu, Tb, Sm activated thiogallate phosphor such as Eu, Tb, Sm, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Y, Ga, Tb, La, Sm, Pr, Lu) ₃ (Al, Ga) ₅ O ₁₂ : Ce-activated aluminate phosphor such as Ce, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, Ca ₃ (Sc, Mg, Na, Li) ₂ Si ₃ O ₁₂ : Ce-activated silicate phosphor such as Ce, CaSc ₂ O ₄ : Ce-activated oxide phosphor such as Ce, SrSi ₂ O ₂ N ₂ : Eu, (Sr, Ba, Ca) Si ₂ O ₂ N _2: Eu, Eu-activated β-sialon, Eu-activated α Saia Eu Tsukekatsusan nitride phosphor such _{emissions, BaMgAl 10 O 17: Eu,} Eu such as Mn, Mn-activated aluminate phosphor, SrAl ₂ O _4: Eu-activated aluminate phosphor such as Eu, (La, Gd, Y) ₂ O ₂ S: Tb-activated oxysulfide phosphor such as Tb, LaPO ₄ : Ce, Tb-activated phosphate phosphor such as Ce, Tb, ZnS: Cu, Al, ZnS : Sulfide phosphor such as Cu, Au, Al, (Y, Ga, Lu, Sc, La) BO ₃ : Ce, Tb, Na ₂ Gd ₂ B ₂ O ₇ : Ce, Tb, (Ba, Sr) ₂ (Ca, Mg, Zn) B ₂ O ₆ : Ce, Tb activated borate phosphor such as K, Ce, Tb, etc., Ca ₈ Mg (SiO ₄ ) ₄ Cl ₂ : Eu, Mn attached, etc. active halosilicate phosphor, (Sr, Ca, Ba) (Al, Ga, In) 2 S 4 Eu-activated thioaluminate phosphor or thiogallate phosphor such as _{Eu, (Ca, Sr) 8} (Mg, Zn) (SiO 4) 4 Cl 2: Eu, Eu such as Mn, Mn-activated halosilicate phosphor Etc. can also be used.

Examples of the blue phosphor include europium-activated barium magnesium aluminate based on BaMgAl ₁₀ O ₁₇ : Eu, which is composed of growing particles having a substantially hexagonal shape as a regular crystal growth shape and emits light in a blue region. Europium-activated halo represented by (Ca, Sr, Ba) ₅ (PO ₄ ) ₃ Cl: Eu, which is composed of phosphors and growing particles having a substantially spherical shape as a regular crystal growth shape and emits light in the blue region. calcium phosphate phosphor, which is constituted by growing particles having a nearly spherical shape typical of regular crystal growth and emits light in the blue region, _{(Ca, Sr, Ba) 2} B 5 O 9 Cl: europium represented by Eu It is composed of active alkaline earth chloroborate phosphors and fractured particles having fractured surfaces, and emits light in the blue-green region (Sr, C Examples include europium-activated alkaline earth aluminate-based phosphors represented by a, Ba) Al ₂ O ₄ : Eu or (Sr, Ca, Ba) ₄ Al ₁₄ O ₂₅ : Eu.

In addition, as the blue phosphor, for example, Sn-activated phosphate phosphor such as Sr ₂ P ₂ O ₇ : Sn, Sr ₄ Al ₁₄ O ₂₅ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, BaAl ₈ O ₁₃ : Eu-activated aluminate phosphor such as Eu, SrGa ₂ S ₄ : Ce, CaGa ₂ S ₄ : Ce-attached thiogallate phosphor such as Ce, (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₀ O ₁₇ : Eu-activated aluminate phosphor such as Eu, Tb, Sm, (Ba, Sr, Ca) MgAl ₁₀ O ₁₇ : Eu, Mn-activated aluminate phosphor such as Eu, Mn, (Sr , Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, (Ba, Sr, Ca) ₅ (PO ₄ ) ₃ (Cl, F, Br, OH): with Eu such as Eu, Mn, Sb Live halo Phosphate _{phosphor, BaAl 2 Si 2 O 8:} Eu, (Sr, Ba) 3 MgSi 2 O 8: Eu -activated silicate phosphor such as _{Eu, Sr 2 P 2 O 7} : with Eu such Eu Active phosphate phosphor, sulfide phosphor such as ZnS: Ag, ZnS: Ag, Al, Ce activated silicate phosphor such as Y ₂ SiO ₅ : Ce, tungstate phosphor such as CaWO ₄ (Ba, Sr, Ca) BPO ₅ : Eu, Mn, (Sr, Ca) ₁₀ (PO ₄ ) ₆ • nB ₂ O ₃ : Eu, 2SrO • 0.84 P ₂ O ₅ • 0.16 B ₂ O ₃ : Eu Eu, Mn activated borate phosphate phosphors such as Eu, and Eu activated halosilicate phosphors such as Sr ₂ Si ₃ O ₈ .2SrCl ₂ : Eu can also be used.

(4) Embodiment 4 of Preferred Uses EL Element Description An organic electroluminescence element (organic EL element) containing a light emitting compound in a light emitting layer can be produced using the luminescent ink of the present invention. An organic electroluminescence element has a laminated structure, and generally has a configuration of an anode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode on a transparent insulating substrate. The light emitting layer of such an organic EL element can be prepared using the luminescent ink of the present invention. Glass, resin, or the like is used as a material for the insulating substrate. As an anode material, a metal such as Au or a transparent electrode such as indium tin oxide (ITO) is used. As a material for the hole injecting and transporting layer, a hydrazone-based or triarylamine-based compound that can effectively transport charges is used. As a material for the electron injecting and transporting layer, tris (8-hydroxyquinolino) aluminum (Alq), an oxadiazole derivative, a perylene derivative, and the like that can efficiently transport electrons to the light emitting layer are used. Mg / Ag, Mg / Au, Al / Li, or the like is used as the cathode material.

  The light emitting layer of the organic EL element can be formed by forming a thin layer by vapor deposition, spin coating, ink jet printing method or the like using the light emitting ink of the present invention. The light emitting layer is formed by, for example, a method in which a light emitting compound is deposited on the surface of the anode or the hole transport layer, or a method in which a light emitting ink containing an appropriate amount of the light emitting organic compound is applied to the surface of the anode or the hole transport layer and dried. Etc. When forming a light emitting layer by apply | coating luminescent ink, it is preferable to use the luminescent ink which contains 1 to 10 weight% of luminescent compounds and 10 to 80 weight% of binder resins.

  Thus, an organic EL device in which the light emitting compound of the present invention represented by the above formula (1) is contained in the light emitting layer as a light emitting dye can be produced. The light-emitting dye in the light-emitting layer is composed of the above light-emitting compound serving as a light-emitting element, a blue light-emitting distyrylbenzene derivative or a green light-emitting tris (8-hydroxyquinolino) aluminum (Alq), and the like. A matrix may be formed. Luminescent dyes such as luminescent organic compounds have the property of emitting light by recombination of holes from the anode or hole injection layer and electrons from the negative electrode or electron injection layer.

  The organic EL device manufactured as described above may be further doped with another fluorescent organic material in the light emitting layer. By doping with other fluorescent organic materials, the light emission efficiency of organic electroluminescence can be improved, thereby enabling full color display. Examples of other fluorescent organic materials include doped dye materials such as stilbene dyes, coumarin dyes, xanthene dyes, quinacridone dyes, europium complexes, zinc porphyrin derivatives, and the like.

  Furthermore, the light emitting layer of an organic EL element can be formed by the inkjet printing method by making the ink composition of this invention contain the polymer which has carrier transport ability.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

Production Example 1
(1-a) Production Example of Compound Example 1-1 Methylpentafluoropropionate 21.4 g (0.12 mol) (manufactured by Lancaster), 2-acetylnaphthalene 17.0 g (0.10 mol) (manufactured by Tokyo Chemical Industry Co., Ltd.) ) In the presence of 16.2 g (0.30 mol) sodium methylate (manufactured by Wako Pure Chemical Industries, Ltd.) in 50 ml of dry ether, and 4,4,5,5,5-pentafluoro-1- (2 -Naphthyl) -1,3-butanedione 30 g was obtained.

  The obtained 4,4,5,5,5-pentafluoro-1- (2-naphthyl) -1,3-butanedione 9.48 g (0.03 mol), europium chloride hexahydrate 3.66 g (0. 01 mol) (manufactured by Wako Pure Chemical Industries, Ltd.) and 30 ml of 1N sodium hydroxide were mixed in 100 ml of ethanol and heated and stirred for 2 hours while adjusting the temperature to 40 ° C., whereby the compound represented by the following formula (a1) Example 1-1 10 g was obtained.

(1-b) Production Example of Compound Example 3-1 2.0 g (1.73 mmol) of the europium complex of Compound Example 1-1, 0.377 g (1.73 mmol) of tributylphosphine oxide and 0.482 g of triphenylphosphine oxide ( 1.73 mmol) was added to 20 ml of chloroform, and the mixture was heated and stirred at 40 ° C. for 0.5 hours to obtain 2.7 g of the light emitting compound of Compound Example 3-1 having the following structure (yield: 98.8%). .

(1-c) Identification of Compound Example 3-1 The light-emitting compound of Compound Example 3-1 obtained was subjected to atomic absorption analysis and elemental analysis. The results are shown in Table 4. ¹ HNMR and ¹³ CNMR were measured, and the results are shown in FIGS. From these results, it is supported that the obtained light-emitting compound has a structure represented by the above formula (b1).

Production Example 2
(2-a) Production Example of Compound Example 1-2 In (2-a) of Production Example 2, methyl heptafluorobutyrate was used instead of methyl pentafluoropropionate of (1-a) of Production Example 1. 34 g of Compound Example 1-2 represented by the following formula (a2) was obtained in the same manner as in (1-a) of Production Example 1 except that the molar amount was used.

(2-b) Production Example of Compound Example 3-4 2.0 g (1.46 mmol) of the europium complex of Compound Example 1-2, 0.319 g (1.46 mmol) of tributylphosphine oxide and 0.407 g of triphenylphosphine oxide ( 1.46 mmol) was added to 20 ml of chloroform, and the mixture was heated and stirred at 40 ° C. for 0.5 hour to obtain 2.4 g of the light emitting compound of Compound Example 3-4 having the following structure (yield: 93.3%). .

(2-c) Identification of Compound Example 3-4 The light emitting compound of Compound Example 3-4 obtained was subjected to atomic absorption analysis and elemental analysis. The results are shown in Table 5. Further, ¹ HNMR and ¹³ CNMR were measured, and the results are shown in FIGS. From these results, it is supported that the obtained light emitting compound has a structure represented by the above formula (b2).

Production Example 3
(3-a) Production Example of Compound Example 1-1 In the same manner as in (1-a) of Production Example 1, Compound Example 1-1 represented by the formula (a1) was obtained.

(3-b) Production Example of Compound Example 3-3 0.482 g (1.73 mmol) of triphenylphosphine oxide in (1-b) of Production Example 1 was replaced with 0.597 g (1.73 mmol) of trioctylphosphine oxide. Otherwise, in the same manner as in Production Example 1, 2.6 g of the light-emitting compound of Compound Example 3-3 represented by the following formula (b3) was obtained.

Comparative production example 1
According to Production Example 1, Comparative Compound Example 1 of the following formula (b4) was synthesized. About the obtained luminescent compound, atomic absorption analysis and elemental analysis were measured and shown in Table 6 to confirm the structure.

Comparative production example 2
According to Production Example 1, a comparative compound example 2 of the following formula (b5) was synthesized. About the obtained luminescent compound, atomic absorption analysis and elemental analysis were measured and shown in Table 7 to confirm the structure.

Comparative production example 3
According to Production Example 1, Comparative Compound Example 3 of the following formula (b6) was synthesized. About the obtained luminescent compound, atomic absorption analysis and elemental analysis were measured and shown in Table 8 to confirm the structure.

Comparative production example 4
According to Production Example 1, Comparative Compound Example 4 of the following formula (b6) was synthesized. About the obtained luminescent compound, atomic absorption analysis and elemental analysis were measured and shown in Table 9 to confirm the structure.

The physical property of the compound obtained by the said manufacture example was confirmed. Compound Example 3-1 and Compound Example 3-4 which are luminescent compounds of the present invention, and compounds having a naphthyl group and a trifluoromethyl group (position of R ¹ of the luminescent compound of the present invention) in the diketone structure as examples of comparative compounds (Comparative Compound Example 1), a compound further having a homoline ligand (Comparative Compound Examples 2 and 3), and a diketone structure having a naphthyl group and a pentafluoroethyl group (position of R ¹ of the luminescent compound of the present invention) ) And a homoline ligand (Comparative Compound Example 4) were used for measurement of physical properties. The fluorescence intensity of these compounds and the solubility (solubility) in the liquid medium were measured by the following methods.

Fluorescence Intensity of Luminescent Compound The fluorescence intensity of the luminescent compound used in the ink composition of the present invention obtained from the above Production Example and the luminescent compound of Comparative Production Example was evaluated. In the evaluation method, 25 mg of each luminescent compound was dissolved in 100 ml of ethanol to obtain a luminescent ink. The fluorescence intensity (photoluminescence intensity PL) of the ink was measured using a fluorescence spectrophotometer (RF-5300PC, manufactured by Shimadzu Corporation). The fluorescence intensity is shown in the following Table 10 as a relative value of fluorescence intensity when the fluorescence intensity of the light emitting compound of Comparative Compound Example 2 is taken as 100.

The solubility of the luminescent compounds was also compared for the solubility of each luminescent compound. The solubility was measured by dissolving in 100 ml of ethanol, chloroform and toluene (TL), leaving it to stand at room temperature for 24 hours, then removing the insoluble matter by filtration, and calculating the solubility (g / solvent 100 ml). When the solubility was high, the measurement was performed in units of about 5.0 g / 100 ml. The results are shown in Table 10 below.

As shown in Table 10, the described fluorescence intensity (emission intensity) from the above results, the compound having a _C 2 _{F 5} group as ^{R 1} Example 3-1 compounds having _{a C} 3 _{F 7} group as 168, ^{R 1} Example 3-4 shows a value of 159, while Comparative Compound Example 1 having a CF ₃ group at the R ¹ position is 139. From this result, it was confirmed that the fluorescence intensity was improved by 20 or more by changing the substituent of the β-diketone derivative coordinated to the europium complex. Further, the fluorescence intensities of Comparative Compound 2 and Comparative Compound 3 were even lower (Comparative Compound Example 2 100, Comparative Compound Example 3 105). That is, it has been confirmed by experiments that the use of the europium complex represented by the formula (1) of the present invention is very effective for increasing the emission intensity. Moreover, even if it compared with the comparative compound example 4, it has confirmed that the Example compound example of this application showed high fluorescence intensity.

Further, when the described solution stability for a liquid medium, the compound Example 3-4 Compound Example 3-1 having a _C 2 _{F 5} group as ^{R 1,} and where the ^{R 1} a _C 3 _{F 7} group are ethanol, chloroform, It showed a solubility of 50 g or more in toluene. On the other hand, Comparative Compound Example 1 having a CF ₃ group at the position of R ¹ has a solubility of 1 g or less in ethanol, low solubility, and 25 to 30 g in toluene, which is slightly inferior in solubility. As a result. Therefore, it was confirmed that the solubility is improved by changing the substituent. It can be seen that the light-emitting compound of the present invention has remarkably high solubility particularly in an alcohol solvent.
Moreover, the solubility of the comparative compound example 2 and the comparative compound 3 showed the still lower solubility (the comparative compound example 2 and the comparative compound example 3 are 10 g or less in said 3 types of solvent). That is, it is important that the light-emitting compound of the present invention has a heterophosphorous ligand. Selecting the europium complex structure having the ligand of the present invention is very effective in increasing the solubility.

Ink composition A
Example 1
1.0 g of Compound Example 3-1 obtained in Production Example 1 was dissolved in 90 g of ethanol and 5 g of ethylene glycol solution, and 4.0 g of 2-pyrrolidone was added thereto to prepare an ink composition. A barcode having the pattern shown in FIG. 6 was printed on plain paper using an inkjet recording apparatus “HG5130 manufactured by Epson Corporation” to obtain a forgery-preventing printed matter of the present invention. When the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, it emitted bright red light.

  The fluorescence spectrum of the ink obtained above is shown in FIG.

Example 2
In Example 2, an ink composition was prepared in the same manner as in Example 1, except that the light emitting compound of Compound Example 3-1 in Example 1 was replaced with the light emitting compound in Table 11 below. In the same manner as in Example 1, using an ink jet recording apparatus, barcode printing was performed on plain paper to obtain an anti-counterfeit printed matter of the present invention. When the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, it emitted bright red light.

  The fluorescence spectrum of the ink obtained in Example 2 is shown in FIG.

Example 3
In Example 3, an ink composition was prepared in the same manner as in Example 1, except that the light emitting compound of Compound Example 3-1 in Example 1 was replaced with the light emitting compound in Table 11 below. In the same manner as in Example 1, using an ink jet recording apparatus, barcode printing was performed on plain paper to obtain an anti-counterfeit printed matter of the present invention. When the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, it emitted bright red light.

Comparative Examples 1-3
In Comparative Examples 1 to 3, ink compositions were prepared in the same manner as in Example 1 except that the light emitting compound of Compound Example 3-1 in Example 1 was replaced with the light emitting compound in Table 11 below. In the same manner as in Example 1, barcode printing was performed on plain paper using an inkjet recording apparatus, and the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, and emitted light.

  The fluorescence spectrum of the ink obtained in Comparative Example 1 is shown in FIG.

Evaluation of Inks of Examples 1 and 2 and Comparative Examples 1 to 3 (a) Stability test over time 100 g of the ink composition obtained above in a transparent container was placed in an incubator under control at 50 ° C. and stored for 1 month. . Thereafter, the stored ink composition was evaluated by visually observing the presence or absence of precipitates. The evaluation criteria were as follows. The obtained results are shown in Table 11.
Evaluation criteria ( circle): The deposit was not recognized.
Δ: Slight precipitation was observed.
X: Many precipitates were recognized.

(B) Visibility test It was evaluated by visually observing whether the printed barcode obtained above was clearly visible under ultraviolet irradiation. The evaluation criteria were as follows. The obtained results are shown in Table 11.
Evaluation criteria A : Visible at a concentration of 0.001% B: Visible at a concentration of 0.01%.
Δ: Difficult to see at a concentration of 0.01%

(C) Relative fluorescence evaluation (i) Initial relative fluorescence evaluation In order to examine the emission intensity of the ink composition obtained above, the fluorescence intensity was measured using a fluorescence spectrophotometer in the same manner as the fluorescence intensity of the light-emitting compound described above. . The fluorescence intensity of each ink composition is a relative value (%) when the fluorescence intensity at 613 nm of the ink composition including Comparative Compound Example 3 (ink compositions obtained in Comparative Examples 3, 6 and 8) is defined as 100. ). The obtained results are shown in Table 11.

(Ii) Thermal Stability Evaluation of Relative Fluorescence Intensity The ink composition obtained above was stored in the dark at 40 ° C. under normal pressure for 5 days, and then the fluorescence intensity was measured again. The relative fluorescence intensity of each ink composition is shown as a relative value with the initial fluorescence intensity of the ink composition containing Comparative Compound Example 3 (the ink compositions obtained in Comparative Examples 3, 6 and 8) as 100, and is shown below. The extinction rate (%) was determined by calculation from both values using the formula (1). The obtained results are shown in Table 11.

A positive value indicates an increase in fluorescence intensity, and a negative value indicates a decrease (quenching) in fluorescence intensity.
The thermal stability of each ink composition was evaluated using the following evaluation criteria.

Evaluation criteria ○: 3% or less △: 3-5% ×: 5% or more

  The comparison of the ink relative fluorescence intensity (%) is based on the initial fluorescence intensity measured using the ink composition containing Comparative Compound Example 3 (ink compositions obtained in Comparative Examples 3, 6 and 8). The relative intensity is shown.

  From the results shown in Table 11 above, the ink obtained in each example has a relative fluorescence intensity (%), and in the initial ink evaluation, the fluorescence intensity is several times superior to the ink obtained in the comparative example. I understand that. It is clear that the fluorescent ink of the present invention has high fluorescence intensity and excellent visibility. In particular, when the initial relative fluorescence intensity was 130 or more, an evaluation result of visibility “◎” was given. In addition, in the stability evaluation of the initial ink, no precipitation was observed in the ink using the light emitting compound of the present invention, whereas precipitation was observed when the comparative compound was used. That is, it was confirmed that the ink using the luminescent compound of the present invention is very excellent in stability with time and storage stability.

Therefore, by selecting R ^{1 of the} luminescent compound represented by the formula (1) used in the ink of the present invention having 2 or more carbon atoms in the perfluoroalkyl chain, and further introducing a heterophosphorous ligand, light emission It can be seen that not only the brightness and solvent solubility / resin compatibility are improved, but also the ink has excellent characteristics with respect to the stability over time.

Ink composition B
Example 4
In 90 g of ethanol and 5 g of ethylene glycol solution, 1.0 g of Compound Example 3-1 obtained in Production Example 1 was dissolved, and 4.0 g of polyvinyl butyral (trade name: ELEX BL-1 manufactured by Sekisui Chemical Co., Ltd.) was dissolved therein. In addition, an ink composition was prepared. Using an inkjet recording apparatus “HG5130 manufactured by Epson Corporation”, barcode printing was performed on plain paper to obtain an anti-counterfeit printed matter of the present invention. When the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, it emitted bright red light.

Example 5
In Example 5, the light emitting compound of Compound Example 3-1 in Example 4 was replaced with the light emitting compound in Table 12 below, and an ink composition was prepared. Bar code printing was performed to obtain a forgery-preventing printed material of the present invention. When the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, it emitted bright red light.

Comparative Examples 4-6
In Comparative Examples 4 to 6, an ink composition was prepared in the same manner as in Example 4 except that the light emitting compound of Compound Example 3-1 of Example 4 was replaced with the light emitting compound of Table 12 below, and an ink jet recording apparatus was used. When barcode printing was performed on plain paper and the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, light was emitted.

Evaluation of Inks of Examples 4 to 5 and Comparative Examples 4 to 6 The inks of Examples 4 to 5 and Comparative Examples 4 to 6 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 12. However, in the relative fluorescence evaluation, a relative value with the initial fluorescence intensity of the ink composition obtained in Comparative Example 6 as 100 was used.

Ink composition C
Example 6
In a solution obtained by adding 30 g of ethyl acetate to 90 g of ethanol and 5 g of ethylene glycol, 1.0 g of the compound 3-1 obtained in Production Example 1 was dissolved, and 4.0 g of a polyacrylate resin (Avicia) was dissolved therein. An ink composition was prepared by adding product name: NeoCRylB-818). Using an inkjet recording apparatus “HG5130 manufactured by Epson Corporation”, barcode printing was performed on plain paper to obtain an anti-counterfeit printed matter of the present invention. When the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, it emitted bright red light.

Example 7
In Example 7, an ink composition was prepared by replacing the light emitting compound of Compound Example 3-1 of Example 6 with the light emitting compound of Table 13 below. In the same manner as in Example 1, using an ink jet recording apparatus, barcode printing was performed on plain paper to obtain an anti-counterfeit printed matter of the present invention. When the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, it emitted bright red light.

Comparative Examples 7-8
In Comparative Example 7, an ink composition was prepared by replacing the light emitting compound of Compound Example 3-1 of Example 6 with the light emitting compound of Table 13 below. In the same manner as in Example 1, barcode printing was performed on plain paper using an inkjet recording apparatus, and the obtained printed matter was irradiated with ultraviolet light (about 365 nm) using a black light lamp, and emitted light.

  The inks of Examples 6 to 7 and Comparative Examples 7 to 8 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 13. However, in the relative fluorescence evaluation, the initial fluorescence intensity of the ink composition obtained in Comparative Example 8 was set to a relative value of 100.

LED Element Production Examples 8 and 9 and Comparative Examples 9 and 10 show production examples of LED elements using the light emitting compound of the present invention.

Example 8
An ink composition D was prepared by dissolving 5 parts of the light emitting compound of Compound Example 3-4 and 15 parts of the fluorine-based polymer of the following formula in 80 parts of ethyl acetate to obtain an ink composition for forming a light emitting layer. This was applied onto a LED chip having a central emission wavelength of 395 nm and emitted (20 mA, 3.4 V voltage). The measured value of the luminous intensity was as large as 200 mcd.

[Wherein, x, y and z are integers of 1 or more. ]

Example 9
A silicon polymer layer containing an alkaline earth metal silicate phosphor that emits yellow light is provided on an LED chip having a central emission wavelength of 395 nm, and the ink obtained in Example 8 is further used on the layer. A second fluorescent layer was formed (20 mA, 3.4 V voltage). The measured value of the luminous intensity was as large as 500 mcd.

Comparative Example 9
A light emitting layer forming ink composition was obtained in the same manner as in Example 8 except that Comparative Compound Example 1 was used instead of Compound Example 3-4 used in Example 8. This was applied onto a LED chip having a central emission wavelength of 395 nm and emitted (20 mA, 3.4 V voltage). The measured value of luminous intensity was 130 mcd.

Comparative Example 10
A light emitting layer forming ink composition was obtained in the same manner as in Example 8, except that Comparative Compound Example 3 was used instead of Compound Example 3-4 used in Example 8. This was applied onto a LED chip having a central emission wavelength of 395 nm and emitted (20 mA, 3.4 V voltage). The measured value of luminous intensity was 120 mcd.

  The ink composition of the present invention is an ink composition that is used to produce various printing inks used for security purposes provided for the prevention of counterfeiting and light-emitting elements containing light-emitting materials in the EL field and LED field. It can be used for the purpose of things. The luminescent ink of the present invention has high sensitivity in color development due to irradiation of ultraviolet rays compared to conventional luminescent inks and has higher luminescence intensity, and therefore can be suitably used for the above applications. . Moreover, the luminescent ink of the present invention has the advantage in industrial use that the amount of emitted light is little decreased even after storage at high temperature, and the stability over time and storage stability are excellent.

It is a ¹ H-NMR spectrum (1a) of Compound Example 3-1 used in the Examples. It is a ¹³ C-NMR spectrum (1b) of Compound Example 3-1 used in the Examples. It is a ¹ H-NMR spectrum (2a) of Compound Example 3-4 used in the Examples. It is a ¹³ C-NMR spectrum (2b) of Compound Example 3-4 used in Examples. 2 is a fluorescence spectrum of inks obtained from Example 1, Example 2, and Comparative Example 1. FIG. It is a figure which shows the pattern of the barcode printed in the Example.

Claims (14)

A luminescent ink containing at least a luminescent compound represented by the following formula (1) and a liquid medium.

[Wherein, R ¹ is a perfluoroalkyl group having 2 to 20 carbon atoms, and L ¹ and L ² are a branched or straight chain alkyl group, a branched or straight chain alkenyl group, an aryl group, and an arylalkyl group, respectively. Group or a perfluoroalkyl group provided that L ¹ and L ² are not the same phosphine oxide. ] The luminescent ink according to claim 1, wherein R ¹ in the formula (1) is a linear perfluoroalkyl group having 2 to 3 carbon atoms. L ¹ and L ² in the formula (1) are phosphine oxides each composed of a branched or straight chain alkyl group or aryl group, provided that L ¹ and L ² are not the same phosphine oxide. The luminescent ink according to claim 1, which is a condition. A luminescent ink containing at least a luminescent compound and a liquid medium, wherein the luminescent compound is mixed with a diketone compound represented by the following formula (3), a trivalent europium salt, and two phosphine oxide derivatives. Luminescent ink which is the obtained europium complex.

[Wherein, R ¹ is a perfluoroalkyl group having 2 to 20 carbon atoms. ]   The luminescent ink according to claim 1, wherein the liquid medium is an alcohol solvent, an ester solvent or an aromatic solvent.   An ink composition for security use, comprising at least the luminescent ink according to claim 1.   An anti-counterfeit printed matter obtained using the ink composition for security purposes according to claim 6.   The manufacturing method of a forgery prevention printed matter including the process printed using the ink composition for security uses which contains the luminescent ink in any one of Claims 1-5 at least.   The ink composition for LED element light emitting layer formation containing the luminescent ink in any one of Claims 1-5 at least.   Furthermore, the ink composition for LED element light emitting layer formation of Claim 9 containing a water repellent polymer.   The ink composition for LED element light emitting layer formation of Claim 10 whose water repellent polymer is a fluorine-type polymer.   The manufacturing method of an LED element including the process of forming the light emitting layer of LED using the ink composition for LED element light emitting layer formation in any one of Claims 9-11.   The LED element obtained using the ink composition for LED element light emitting layer formation in any one of Claims 9-11.   14. The LED according to claim 13, wherein the phosphor layer contains at least one inorganic phosphor that emits yellow, green, or blue light and the light-emitting compound represented by the formula (1) of claim 1. element.

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