Use of 4-bora-3A,4A-diaza-s-indacenes for security purposes

Abstract

The invention relates to the use of one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family for the preparation of a security element for a product, in particular a document, said security element comprising a polymer and said compound(s) being incorporated in said polymer, and to a method for ensuring the security of a product, in particular that of a document.

Claims

1. Securing element of a product, said securing element comprising a polymer and one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family, said compound being incorporated in said polymer and is chosen from those of formula I: ##STR00044## wherein, R.sup.1 is a phenyl substituted by one or several groups chosen from methyl, fluoro, hydroxy, acetyl and methacrylate; R.sup.2 and R.sup.2′ are independently chosen from hydrogen and C1 to C2 alkyl; R.sup.3 and R.sup.3′ are independently chosen from hydrogen, aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, alkynyl, said aryl, heteroaryl, cycloalkyl, alkyl, alkenyl and alkynyl being unsubstituted or substituted by one or several groups chosen from C1 to C4 alkyl, aryl, hydroxy and ferrocene, said aryl group being unsubstituted or substituted by one or several groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being unsubstituted or substituted by a C1 to C2 alkyl group; R.sup.4 and R.sup.4′ are independently chosen from aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, said aryl, heteroaryl, cycloalkyl, alkyl and alkenyl being unsubstituted or substituted by one or several groups chosen from C1 to C3 alkyl, aryl, hydroxy and ferrocene, said aryl group being unsubstituted or substituted by one or several groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being unsubstituted or substituted by a C1 to C2 alkyl group; R.sup.5 is C1 to C4 alkyl or C1 to C4 alkenyl; R.sup.6 and R.sup.6′ are independently chosen from halogens, C1 to C4 alkyl, C2 to C4 alkenyl or aryl, said aryl being unsubstituted or substituted by one or several groups chosen from 01 to C2 alkyl, hydroxy, R5COO— and halogen.

2. The securing element according to claim 1, wherein the compound of the 4-bora-3a,4a-diaza-s-indacene family are chosen from: ##STR00045## ##STR00046## ##STR00047## ##STR00048## ##STR00049## ##STR00050## ##STR00051## ##STR00052## ##STR00053##

3. The securing element according to claim 1, wherein the polymer is chosen from polycarbonate, polyester, polystyrene, polyethylene, polypropylene, polyethylene terephthalate, polyacrylate, polymethacrylate, poly(vinyl chloride), polyamides, polyaramides, ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), cyanoacrilate, rosin resins, pine resins, light-curing resins or mixtures thereof.

4. The securing element according to claim 1, wherein the polymer is chosen from polycarbonate, polyester, polypropylene, thermoplastic polyurethane and light-curing resins.

5. The securing element according to claim 1, wherein the polymer is polycarbonate, polyester, polypropylene or mixtures thereof.

6. The securing element according to claim 1, wherein it has the form of a layer.

7. The securing element according to claim 6, wherein the layer has a thickness ranging from 0.050 mm to 0.800 mm.

8. The securing element according to claim 6, wherein the layer is a film.

9. The securing element according to claim 6, wherein the polymer is polycarbonate and the layer has a thickness ranging from 100 μm to 800 μm.

10. The securing element according to claim 6, wherein the polymer is polypropylene and the layer has a thickness ranging from 15 μm to 100 μm.

11. The securing element according to claim 1, wherein the securing element is an ink or varnish.

12. The securing element according to claim 1, wherein the securing element is an adhesive.

13. Method for securing a product comprising the step of: preparing a securing element comprising a polymer and one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family, said compound being incorporated in said polymer and is chosen from those of formula I: ##STR00054## wherein, R.sup.1 is a phenyl substituted by one or several groups chosen from methyl, fluoro, hydroxy, acetyl and methacrylate; R.sup.2 and R.sup.2′ are independently chosen from hydrogen and C1 to C2 alkyl; R.sup.3 and R.sup.3′ are independently chosen from hydrogen, aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, alkynyl, said aryl, heteroaryl, cycloalkyl, alkyl, alkenyl and alkynyl being unsubstituted or substituted by one or several groups chosen from C1 to C4 alkyl, aryl, hydroxy and ferrocene, said aryl group being unsubstituted or substituted by one or several groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being unsubstituted or substituted by a C1 to C2 alkyl group; R.sup.4 and R.sup.4′ are independently chosen from aryl, heteroaryl, cycloalkyl, alkyl, alkenyl, said aryl, heteroaryl, cycloalkyl, alkyl and alkenyl being unsubstituted or substituted by one or several groups chosen from C1 to C3 alkyl, aryl, hydroxy and ferrocene, said aryl group being unsubstituted or substituted by one or several groups chosen from aryl, C1 to C2 alkyl, halogen, hydroxy, dimethylamino, nitro, said aryl being unsubstituted or substituted by a C1 to C2 alkyl group; R.sup.5 is C1 to C4 alkyl or C1 to C4 alkenyl; R.sup.6 and R.sup.6′ are independently chosen from halogens, C1 to C4 alkyl, C2 to C4 alkenyl or aryl, said aryl being unsubstituted or substituted by one or several groups chosen from C1 to C2 alkyl, hydroxy, R5COO— and halogen; applying said prepared securing element to the product to be secured.

14. The method for securing according to claim 13, wherein the application of said securing element is carried out over at least one portion of said product to be secured.

15. The method for securing according to claim 13, wherein the product to be secured is an identity, fiduciary or administrative document.

16. The method for securing according to claim 13, wherein the polymer is chosen from polycarbonate, polyester, polystyrene, polyethylene, polypropylene, polyethylene terephthalate, polyacrylate, polymethacrylate, poly(vinyl chloride), polyamides, polyaramides, ethylene vinyl acetate (EVA), polyurethane, thermoplastic polyurethane (TPU), cyanoacrilate, rosin resins, pine resins, light-curing resins and mixtures thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the absorption spectrum of the layers of polycarbonate with a thickness of about 0.400 mm incorporating respectively 0.05% and 0.005% by weight of fluorescent dye.

(2) FIG. 2 shows the fluorescence spectrum of a layer of polycarbonate with a thickness of about 0.400 mm incorporating 0.005% by weight of fluorescent dye.

(3) FIG. 3 shows the transmission spectrum of a layer of polycarbonate with a thickness of about 0.400 mm incorporating 0.1% by weight of fluorescent dye.

EXAMPLES

Example 1: Preparation of a Transparent Layer of a Securing Element with a Polycarbonate Polymer Base Incorporating a Fluorescent Dye

(4) For this example of a securing element, the polymer chosen is polycarbonate sold under the reference Makrolon® 2658 by Bayer.

(5) The fluorescent dye chosen is 2,8-diethyl-5,5-difluoro-10-mesityl-3, 7-di(thiophen-2-yl)-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide of formula:

(6) ##STR00042##

(7) This fluorescent dye absorbs at 590 nm and has a fluorescence emission at 641 nm.

(8) In order to determine the quantities of fluorescent dyes to be incorporated so as to obtain a transparent layer, the following four test compositions were prepared:

(9) Composition 1: polycarbonate Makrolon® 2658 mixed with 1% fluorescent dye.

(10) Composition 2: polycarbonate Makrolon® 2658 mixed with 0.05% fluorescent dye.

(11) Composition 3: polycarbonate Makrolon® 2658 mixed with 0.0167% fluorescent dye.

(12) Composition 4: polycarbonate Makrolon® 2658 mixed with 0.005% fluorescent dye.

(13) The percentages are expressed by weight in relation to the total weight of the fluorescent dye.

(14) The four compositions were then extruded using a PLASTI-CORDER® extruder sold by BRADENDER and which has the characteristics hereinafter Diameter of the screw: 25 mm Length of the screw: 40 D Speed range: 0-150 rpm Maximum torque: 2×90 Nm Two filling sections A degassing section Temperature range for extrusion: 260° C.-290° C. Extrusion pressure: ambient pressure

(15) The extruder makes it possible to obtain granules or beads which will undergo a step of thermocompression in order to obtain the layers of securing element. The granules or beads were therefore thermocompressed in moulds.

(16) The equipment used for this step is a LESCUYER press of which the plates of the press were heated to 290° C. and the compression was carried out at 50 bars for 2 to 3 min.

(17) After cooling, layers of securing element of 10 cm×10 cm are obtained and have a thickness of about 0.400 mm.

(18) Pour each composition, a layer was prepared according to the description hereinabove.

(19) For each layer, the absorption and fluorescence spectra were recorded.

(20) FIG. 1 shows the absorption spectra of the layers of polycarbonate incorporating 0.05% and 0.005% by weight of fluorescent dye, respectively. A bathochromic displacement (shift) is observed of λ.sub.max in relation to the absorption spectrum of the fluorescent dye in solution which has a λ.sub.max of 588 nm. For this layer made of polycarbonate, the λ.sub.max of absorption measured are indeed 600 nm (0.05% of fluorescent dye) and 599 nm (0.005% of fluorescent dye). The maximum absorbances (abs.sub.max) and the concentration in fluorescent dye were also determined. The latter was determined by using the value ε in solution (45000 mol.Math.L.sup.−1.Math.cm.sup.−1). The results are summarised in table 2 hereinafter.

(21) TABLE-US-00002 TABLE 2 Sample 0.05% fluorescent dye 0.005% fluorescent dye λ.sub.max (nm) 600 599 abs.sub.max 0.81 0.05 Concentration 4.51E−05 2.84E−06 (mol .Math. L.sup.−1 .Math. cm.sup.−1)

(22) FIG. 2 shows the fluorescence spectra of the layer of polycarbonate containing 0.005% fluorescent dye with an excitation wavelength of 580 nm and 600 nm respectively. A slight hypsochromic displacement (shift) of λ.sub.max is observed in relation to the fluorescence spectrum of the fluorescent dye in solution which has a λ.sub.max of 644 nm. For this layer made of polycarbonate, the λ.sub.max measured are indeed 641 nm for an excitation wavelength of 600 nm and 640 nm for an excitation wavelength of 580 nm.

(23) With regards to the transmission of light, the layer obtained using composition 1, with a concentration in fluorescent dye of 0.1% by weight with respect to the total weight of the polymer does not transmit below 650 nm (cf. FIG. 3).

(24) Composition 3 makes it possible to obtain a layer of transparent fluorescent securing element that allows light to pass which as such makes it possible to change the colour according to the incident light beams.

(25) Other tests were conducted by varying the fluorescent dyes used but while retaining the same concentrations. Films having absorbance wavelengths ranging from 516 nm to 727 nm and fluorescence wavelengths ranging from 527 nm to 742 nm were as such obtained.

Example 2: Preparation of a Transparent Layer of a Securing Element with a Base of Polyurethane Thermoplastic Polymer Incorporating a Fluorescent Dye

(26) For this example, the polymer chosen is the thermoplastic polyurethane sold under the reference Desmopan® DP 9386A by Bayer.

(27) The fluorescent dye chosen is 2,8-diethyl-5,5-difluoro-1,3,7,9-tetramethyl-10-(perfluorophenyl)-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide of the formula hereinbelow (O.V.M 6):

(28) ##STR00043##

(29) The dye chosen absorbs at 544 nm and has a fluorescence emission at 558 nm.

(30) In order to obtain a transparent fluorescent layer, three test compositions were as such prepared:

(31) Composition 1: thermoplastic polyurethane Desmopan® DP 9386A mixed with 0.05% fluorescent dye.

(32) Composition 2: thermoplastic polyurethane Desmopan® DP 9386A mixed with 0.0167% fluorescent dye.

(33) Composition 3: thermoplastic polyurethane Desmopan® DP 9386A mixed with 0.005% fluorescent dye.

(34) The percentages are expressed by weight in relation to the total weight of the fluorescent dye.

(35) For each composition, a layer was prepared according to an operating procedure identical to the one of example 1.

(36) The three compositions prepared with a base of polyurethane thermoplastic polymer make it possible to obtain layers of securing element that have the same appearance and the same transparency as those obtained with the compositions prepared with the polycarbonate polymer base.

(37) The spectrophotometric analyses of the various layers of securing element obtained show that the incorporation of the fluorescent dye into the thermoplastic polyurethane does not alter its performance in terms of absorption and emission of fluorescence.

(38) The possibilities of incorporating fluorescent dyes of this invention are as such demonstrated.