DE60203541T2 - Rare earth metal compounds and their mixtures - Google Patents

Description

The The invention relates to rare earth metal compounds and mixtures of these, due to their luminescence, when irradiated with UV light is excellent for marking objects, such as disks and documents.

fluorescent Rare earth metal compounds, such as salts or complexes, are made known in the art.

For applications, in which a red fluorescence effect is required, have so far been predominantly Europium-diketonate complexes (see H. G. Brittain and F. S. Richardson, J. Amer. Chem. Soc. 99, 65-70 (1977)) and europium-carboxylic acid compounds (cf. G. Kallistratos, Chemika Chronika, New Series, 11, 249-266 (1982; E.P. Diamandis, Analyst, 117, 1879-1884 (1992)).

The Europium-diketonate complexes can both in solid form and in the form of solutions or mixtures in organic solvents or polymer systems with UV light of a wavelength of 366 nm or 254 nm be excited to emit an intense red fluorescent light (See G.A. Crosby et al., J. Phys. Chem., 66, 2493-2499 (1962)). Also, from US-A-5-118 349 are soluble rare earth-diketonate complexes known. Decisive disadvantages of these complexes are theirs low light stability and their low thermal stability.

Europium-carboxylic acid complexes usually have the desired thermal stability. However, it turns out that in the presence of these complexes in finely divided or amorphous form intense fluorescence only when irradiated with very short-wave UV light, z. With light a wavelength of 254 nm, can be achieved. When grinding these carboxylic acid complexes z. For example the production of offset printing inks therefore causes a shift of the excitation maximum in the short-wave region, d. H. the fluorescence intensity is at Irradiation with short-wave UV light significantly higher than with irradiation with long-wave UV light. Next is the luminescence effect in these complexes back to their crystal structure, as is known with the inorganic luminescent pigments. A destruction of Crystals therefore have a direct influence on the luminescence properties (see DE-A-30 32 611).

• – farblos bei Tageslicht
• – hohe Intensität des emittierten Fluoreszenzlichtes bei Bestrahlung mit UV-Licht einer Wellenlänge von 366 nm
• – hohe thermische Stabilität
• – hohe Lichtechtheit
• – keine Veränderung der Fluoreszenzeigenschaften (Intensität und CIE-Farbkoordinaten) bei Vermahlung.

As a result of the aforementioned disadvantages of the known materials, the object of the invention was to provide fluorescent rare earth metal compounds having the following properties:

• - colorless in daylight
• - High intensity of the emitted fluorescent light when irradiated with UV light of a wavelength of 366 nm
• - high thermal stability
• - high lightfastness
• - no change in fluorescence properties (intensity and CIE color coordinates) when ground.

These Task is surprisingly through the rare earth metal compounds and the mixtures of these compounds according to claims 1 to 7 dissolved. The The invention further relates to a method for the production the rare earth metal compounds and the mixtures of these according to claims 8 to 11, the use according to claims 12 to 17 and the Rare earth metal compounds or mixtures of these containing marked objects according to claim 18th

The Compounds of the invention are rare earth metal compounds of at least one rare earth metal and 2-hydroxyquinoline-4-carboxylic acid of the formula (I)

Wherein L ¹ , L ² , L ³ , L ⁴ and L ⁵ independently represent a substituent or H.

The Compounds of the invention or mixtures of these are colorless under the influence of daylight, however, when excited with ultraviolet light, it fluoresces depending on the metal ion used in different colors. by virtue of of these properties They are used in a variety of applications, and examples for possible applications are z. B. in DE-A-30 32 611 discloses.

The rare-earth metal compounds according to the invention are the result of extensive research in the field of the organic rare earth metal salts to luminescence-capable compounds find, which also have the aforementioned properties.

To In particular, europium chelate complexes with different properties have been used for this purpose substituted quinolinecarboxylic acids examined more closely. For this purpose, see Examples 1 to 11 and the table listed there 1, reference is made. It turned out that the complexes with the majority of the investigated quinolinecarboxylic acids as before, the described disadvantages of the prior art have known materials. In contrast, it is surprising that only those Complexes that are in the 2-position of quinoline carboxylic acid with a hydroxy group, all the desired properties exhibit.

preferred Rare earth metal compounds and mixtures of these have at least two different rare earth metals. Such materials are able to emit different fluorescent light, when the temperature changed becomes. This behavior and the resulting benefits in use the compounds of the invention and mixtures especially for marking and authentication, d. H. the determination of the authenticity of objects will be explained below.

wobei
A und B für unterschiedliche Seltenerdmetalle aus der Gruppe Europium, Terbium, Gadolinium, Samarium, Yttrium, Neodym, Lanthan und Cer stehen,
C ein Erdalkalimetall aus der Gruppe Calcium, Strontium und Barium ist,
L¹, L², L³, L⁴ und L⁵ unabhängig voneinander für einen Substituenten oder H stehen,
x + y eine Zahl ergibt, die größer als 0 und kleiner oder gleich 1 ist, und N = x + y + 2 ist.Particularly preferred rare earth metal compounds and mixtures of these correspond to the general formula (II)

in which
A and B represent different rare earth metals from the group europium, terbium, gadolinium, samarium, yttrium, neodymium, lanthanum and cerium,
C is an alkaline earth metal from the group calcium, strontium and barium,
L ¹ , L ² , L ³ , L ⁴ and L ⁵ independently represent a substituent or H,
x + y gives a number greater than 0 and less than or equal to 1, and N = x + y + 2.

there is taken into account, that the formula (II) only the ratio of the individual components of Indicates connections to each other. The type of bond between the 2-Hydroxy-quinoline-4-carboxylic acid and The metals have not been finally clarified. However, it is believed to be a complex one Binding and the 2-hydroxy-quinoline-4-carboxylic acid as the anion and the metals as Cations present. In such a complex would be one Bonding of metals both over the carboxylate group, the hydroxyl group as well as the lone pair of electrons of the nitrogen atom conceivable.

It It is preferable that the rare earth metals A and B are independently be selected from the group europium, terbium, gadolinium and neodymium. It is particularly preferred that A or B is europium or terbium.

Further investigations have surprisingly shown that in the presence of two different rare earth metals, ie when x is greater than 0 and y is greater than 0, the compounds of the invention emit a fluorescent light when excited with UV light, the color of which depends on the temperature. For example, compounds according to the invention which contain europium with terbium showed an intense orange-red fluorescence upon irradiation with UV light at room temperature, which turns green when cooled to -20 to -30 ° C. This surprising property of the emission of different fluorescent light depending on the temperature is very useful especially when using the compound according to the invention for marking objects. For conventional pigments, one of the Tem emit temperature substantially independent type of fluorescent light, can in marked with objects such. As credit cards, only one type of fluorescent light to be tested by irradiation with UV light. In contrast, labeled with the compounds of the invention objects, for. B. at temperature decrease, z. B. by spraying with conventional cold spray, emit a fluorescent light completely different color, and this behavior then confirms the user that the examined object is actually marked and thus authentic, ie genuine. The imitation of the mark by counterfeiters is made even more difficult.

It is further preferred that the substituents L ¹ , L ² , L ³ , L ⁴ and L ⁵ present in the 2-hydroxy-quinoline-4-carboxylic acid are independently of one another H, halogen, C ₁ -C ₆ -alkoxy, C C ₁ -C ₆ -alkyl, C ₆ -C ₁₂ -aryl, OH, CN, C ₁ -C ₆ -alkylamino, CO-C ₁ -C ₆ -alkyl or CO-NH ₂ .

The rare-earth metal compounds according to the invention and mixtures of these are preferably prepared in the manner that at least one rare earth metal salt with 2-hydroxy-quinoline-4-carboxylic acid of the formula (I) optionally reacted in the presence of an alkaline earth metal salt becomes. The rare earth metal salt is preferred to a rare earth metal halide, such as. B. a chloride.

The Implementation usually takes place in an aqueous Medium and especially in water instead.

Especially Preferably, the 2-hydroxy-quinoline-carboxylic acid is first with alkaline substances under Formation of 2-hydroxy-quinoline-4-carboxylate reacted. As alkaline substances find in particular potassium hydroxide or sodium hydroxide, but also organic amines, such as ethanolamine or Alkylamine application. Also, mixtures of alkaline substances can be used become.

The after the reaction usually as a precipitate resulting product becomes commonplace Way isolated and dried and then in this form for the planned Applications are used.

The rare-earth metal compounds according to the invention and mixtures of these show the already mentioned property when irradiated with UV light fluorescent light visible in the visible range to emit. In the case of using two different ones Rare earth metals in the compounds or in mixtures of Compounds each having a rare earth metal may be the most advantageous property occur that the wavelength of the emitted fluorescent light depends on the temperature. To this Way is z. B. a change the obtained when irradiated with UV light at room temperature color of Fluorescence light to recognize another color, z. For example the material is cooled to lower temperatures.

Also are the compounds of the invention across from solvents much more stable because they show pigment-like character. Further change the fluorescence properties of the compound and in particular the intensity the emitted fluorescent light when grinding the compounds Not. They are above In addition, it is highly thermally stable and usually irradiated colorless with daylight. Because of these properties they can used in a variety of applications for luminescent substances become. Examples of this are given in DE-A-195 12 773.

Prefers become the rare earth metal compounds of the invention and the mixtures of these compounds are used for marking objects, by mixing the object with the compounds or mixtures of this is provided.

at these objects These are mainly data media or documents, with the disk in particular chip cards, check cards or credit cards and as Documents IDs, banknotes and deeds are used.

Since the compounds of the invention are colorless when exposed to sunlight, they produce in this use a not recognizable to the viewer mark, which is just important for such objects that, such. As chip cards, check cards or credit cards and ID cards, banknotes and documents, often counterfeiting attempts are exposed. The irradiation of these objects with UV light, however, produces a characteristic fluorescent light, which in the particular embodiment described in more detail above, even with temperature change, such as cooling, z. B. by spraying the article with a commercially available cryogenic spray, changed color. Each of specific compounds of the invention and mixtures of these generated colors of the fluorescent light at room temperature and modified, z. B. lowered temperature, is then for the verifier of a marked item a sure indication that it has been marked with the connections. Thus, the compounds of the invention are used to prevent counterfeiting or the detection of counterfeiting and the determination of the authenticity of objects.

The Compounds of the invention or mixtures of these as such incorporated into the objects to be marked in the usual way become. However, it is also conceivable that they are in the form of compositions are used, the compounds or mixtures of these included with a binder. Come as a binder in particular acrylic polymers, polyamides, polyurethanes, polyesters and polyethylene terephthalates and the corresponding monomers and Oligomers in question. Also can These compositions usual Additives are added.

Further can the compounds of the invention also in films, such as polymer films, or fibers, such as spin-dyed fibers, be used.

It It is also conceivable that the compounds of the invention together with a liquid carrier, e.g. B. be used in the form of dispersions. Such dispersions can then for example for impregnation the objects to be marked be used. Such an approach is z. For manufacturing of marked security threads possible, then z. B. in ID cards, banknotes, checks and documents incorporated become.

The Invention finally relates also marked objects, the rare earth metal compounds of the invention and mixtures of these.

The The invention is explained in more detail below with reference to examples.

It were a number of compounds of europium and different substituted quinolinecarboxylic acids made to influence the kind of substitution of quinoline carboxylic acid on to check the properties of the compounds obtained.

The Preparation of the compounds was carried out analogously to the below Regulations for Examples 1 and 9.

The quinolinecarboxylic acid europium compounds obtained, which are believed to be chelated complexes visually on the intensity it emitted fluorescent light when irradiated with UV light a wavelength examined by 366 nm. There were each the solid, one solution in toluene and a composition applied to a substrate, containing 5% by weight of the compound in a binder system.

Further became the UV stability tested compounds prepared by the manufactured Spreads in a SOL 2 device the Fa. D. Höhnle exposed to sunlight of daylight D65 for several hours and then visually under UV light the brightness of each emitted fluorescent light observed and comparing the compounds with each other and with literature-known rare earth metal complexes was rated.

The The results obtained are shown in Table 1 below.

• 1. Sowohl die Europium-Verbindungen mit 3-Hydroxy-4-chinolincarbonsäure (Beispiele 2 und 3) als auch diejenigen mit Hydroxy-2-chinolin-carbonsäure (Beispiele 7 und 8) zeigen keine oder nur eine sehr geringe Fluoreszenz.
• 2. Fehlt die Hydroxy-Gruppe völlig in der Chinolincarbonsäure, so erhält man Verbindungen mit nur geringer Intensität des Fluoreszenzlichtes (Beispiele 5, 6 und 10). Eine Ausnahme ist lediglich die Verbindung mit 2-Phenyl-4-Chinolincarbonsäure (Beispiel 9), die sowohl in Lösung als auch im Aufstrich eine sehr intensive Fluoreszenz zeigt. Diese Verbindung hat jedoch als entscheidenden Nachteil, dass sie nur eine sehr geringe UV-Stabilität, d. h. eine sehr geringe Lichtechtheit aufweist.
• 3. Die Verbindung gemäß Beispiel 4 zeigt, dass allein durch die Hydroxy-Gruppe in der 2-Position nur eine geringfügig fluoreszierende Verbindung gebildet wird.
• 4. Nur die erfindungsgemäße Verbindung gemäß Beispiel 1, in der sowohl die Hydroxy- aus auch die Carbonsäuregruppe an der richtigen Position im Chinolingrundkörper vorhanden sind, zeigt die gewünschten Eigenschaften.

From the results given in the table, the following can be read.

• 1. Both the europium compounds with 3-hydroxy-4-quinolinecarboxylic acid (Examples 2 and 3) and those with hydroxy-2-quinoline-carboxylic acid (Examples 7 and 8) show little or no fluorescence.
• 2. If the hydroxy group is completely absent in the quinoline carboxylic acid, compounds with only low intensity fluorescent light are obtained (Examples 5, 6 and 10). An exception is only the compound with 2-phenyl-4-quinolinecarboxylic acid (Example 9), which shows a very intense fluorescence both in solution and in the spread. However, this compound has as a significant disadvantage that it has only a very low UV stability, ie a very low light fastness.
• 3. The compound according to Example 4 shows that only a slightly fluorescent compound is formed solely by the hydroxy group in the 2-position.
• 4. Only the compound according to the invention according to Example 1, in which both the hydroxy and the carboxylic acid group are present at the correct position in Quinolingrundkörper shows the desired properties.

example 1

It became a europium compound according to the invention produced.

For this In a 1 liter 3-neck round bottom flask, 30 g (0.1585 mol) of 2-hydroxyquinoline-4-carboxylic acid in 420 ml of water and by adding 6.34 g of sodium hydroxide dissolved.

To the resulting clear solution was stirring at 20-100 ° C a solution of 9.31 g of europium oxide in 15.64 g of 37% hydrochloric acid and 100 ml of water within dropped by 20 minutes.

Of the Thereupon precipitating europium compound was isolated and dried. It showed when irradiated with long-wave UV light (366 nm) reddish-orange fluorescence.

Example 9

To For comparison, a europium-2-phenylquinoline-4-carboxylic acid compound was prepared.

For this were in a 1 three-necked round bottomed flask 19.75 g (0.0792 mol) of 2-phenylquinoline-4-carboxylic acid in a solution of 5.23 g of potassium hydroxide in 420 ml of water.

To this solution became a solution of 4.65 g of europium oxide in 7.95 g of 37% hydrochloric acid and 150 ml of water.

The Thereupon precipitating compound was isolated and dried. She was in use organic solvents good soluble, so that in general the possibility would exist to use them in printing systems that are still unwanted organic solvents based.

One very big Disadvantage, however, is the strong migration from the binder used, because the compound is soluble is, and the very low light resistance, which is reflected in a very strong drop in the intensity of the Fluorescent light after irradiation with daylight shows.

For outdoor use the connection is therefore not suitable.

Examples 12-15

It were further rare earth metal compounds of the invention or mixtures thereof.

The substances obtained by these examples had a pronounced pigment character, d. H. they are insoluble in common organic solvents. By appropriate fine grinding under normal light colorless, However, under UV light of 366 nm very strongly colored fluorescent light obtained emitting materials.

This makes it possible, with the compounds of the invention, all known printing systems, eg. As water-dilutable, oxidatively dried and UV-reactive printing systems with high light resistance to manufacture.

Example 12

It became a europium-gadolinium compound according to the invention produced.

For this were in a 1 liter three-necked round bottom flask 30 g (0.1585 mol) of 2-hydroxyquinoline-4-carboxylic acid in a solution Dissolved 6.34 g of sodium hydroxide in 420 ml.

To the resulting clear solution was stirring at 20-100 ° C a solution of 8.376 g of europium oxide and 0.959 g of gadolinium oxide in 15.64 g of 37% strength hydrochloric acid and 120 ml of water added dropwise within 15-30 minutes.

The Thereupon precipitating compound was isolated and dried.

Example 13

It became a europium-terbium compound according to the invention produced.

For this were in a 1 liter three-necked round bottom flask 30 g (0.1585 mol) of 2-hydroxyquinoline-4-carboxylic acid in a solution of 6.34 g of sodium hydroxide dissolved in 400 ml of water.

To the solution obtained was stirring at 20-100 ° C a solution of 8.376 g of europium oxide and 0.989 g of terbium oxide in 15.89 37% hydrochloric acid and 100 ml of water added dropwise within 30 minutes.

Of the precipitate was collected and dried. A sample of the obtained compound showed by irradiation with UV light of one wavelength from 366 nm an intense orange-red fluorescence that occurs at Cooling to -20 to -30 ° C in one green fluorescence changed.

Example 14

It became a gadolinium-terbium compound according to the invention generated.

For this were in a 1 liter three-necked round bottom flask 30 g (0.1585 mol) of 2-hydroxyquinoline-4-carboxylic acid in 400 ml of water and by adding 10.46 g of potassium hydroxide dissolved.

To this solution was slowly at 20-100 ° C a solution of 8.63 g of gadolinium oxide and 0.989 g of terbium oxide in 15, 89 g 37% hydrochloric acid and added dropwise 100 g of water.

It Thereupon a fine precipitate formed, which by suction isolated and then dried.

A Sample of the precipitate showed in a spread in commercial, water-dilutable acrylic paint after drying and irradiation with UV light (366 nm) no visible Fluorescence. However, if the spread is cooled to about -20 ° C, it was an intense one green fluorescence visible, noticeable.

Examples 15 and 16

To Comparison purposes were also according to Example 9 nor metal compounds of cinnamic acid and 2-phenylquinoline-4-carboxylic acid with terbium europium, and gadolinium europium and gadolinium terbium.

None However, the obtained compounds showed a color change the fluorescence when irradiated with UV light of 366 or 254 nm, when cooled to -50 ° C.

Claims (18)

Rare earth metal compounds of at least one rare earth metal and 2-hydroxy-quinoline-4-carboxylic acid of the formula (I),

wherein L ¹ , L ² , L ³ , L ⁴ and L ⁵ independently represent a substituent or H, as well as mixtures of these compounds. Rare earth metal compounds and mixtures of these according to claim 1, which comprises at least two different rare earth metals exhibit. Rare earth metal compounds and mixtures of these according to claim 1 or 2 which correspond to the general formula (II)

wherein A and B are different rare earth metals from the group europium, terbium, gadolinium, samarium, yttrium, neodium, lanthanum and cerium, L ¹ , L ² , L ³ , L ⁴ and L ⁵ independently represent a substituent or H, y + y gives a number greater than 0 and less than or equal to 1, and N equals x + y + 2. Rare earth metal compounds and mixtures of these according to claim 3, wherein x is greater than 0 and y greater than 0 are. Rare earth metal compounds and mixtures of these according to claim 3 or 4, wherein A and B independently represent a rare earth metal from the group of europium, terbium, gadolinium and neodymium. Rare earth metal compounds and mixtures of these according to one of the claims 3 to 5, where A or B is for Europium or terbium. Rare earth metal compounds and mixtures of any of claims 3 to 6 wherein L ¹ , L ² , L ³ , L ⁴ and L ^{5 are} independently H, halo, C ₁ -C ₆ alkoxy, C ₁ -C ₆ Alkyl, C ₁ -C ₁₂ -aryl, OH, CN, C ₁ -C ₆ -alkyl, CO-C ₁ -C ₆ -alkyl or CO-NH ₂ . Process for the preparation of the rare earth metal compounds and the mixtures of these according to one the claims 1 to 7, in which at least one rare earth metal salt with 2-hydroxyquinoline-4-carboxylic acid of Formula (I), optionally in the presence of an alkaline earth metal salt reacted becomes. The method of claim 8, wherein the rare earth metal salt is a rare earth metal halide. Process according to Claim 8 or 9, in which the 2-hydroxyquinoline-4-carboxylic acid (I) first converted to 2-hydroxy-quinoline-4-carboxylate by reaction with alkaline substances becomes. The method of claim 10, wherein the potassium hydroxide or sodium hydroxide, an ethanolamine or an alkylamine as alkaline Substance is used. Use of the rare earth metal compounds and Mixtures of these according to claims 1 to 7 for marking objects, by bringing the object with the compounds or mixtures of these is provided. Use according to claim 12, wherein the objects are data carriers or Documents are. Use according to claim 13, wherein as data carrier chip cards, Check cards or credit cards are used. Use according to claim 13, wherein as documents ID cards, banknotes and certificates are used. Use according to any one of claims 12 to 15, wherein the rare earth metal compounds and mixtures of these are used in the form of compositions which they contain together with a binder. Use according to claim 16, wherein as binder Acrylic polymers, polyamides, polyurethanes, polyesters and polyethylene terephthalates be used. Marked items containing the rare earth metal compounds or mixtures of these according to one the claims 1 to 7 included.