WO1999019409A1

WO1999019409A1 - Means and process for uv-detectable labeling of objects

Info

Publication number: WO1999019409A1
Application number: PCT/HU1997/000063
Authority: WO
Inventors: Ferenc FORGÓ
Original assignee: Forgo Ferenc
Priority date: 1997-10-14
Filing date: 1997-10-14
Publication date: 1999-04-22
Also published as: AU4879397A

Abstract

The present invention relates to a process for labeling objects in a UV-detectable way as well as means which can be used in the said process. According to the invention, a composition is provided which contains 2,5-bis(5-tert-butyl-2-benzoxalyl)-thiophene as UV-active component and at least one solvent selected from esters, ethers, aromatic solvents and ketones. Another object of the invention is a fiber pen filled with the above composition. The invention also relates to the use of the composition and/or the UV-active component for labeling different objects.

Description

Means and process for UV-detectable labeling of objects

FIELD OF THE INVENTION

The present invention relates to a process for labeling objects in a UV-detectable way as well as means which can be used in the said process. DESCRIPTION OF THE PRIOR ART

Identification of different objects becomes more and more necessary in the daily life, to prevent falsification on one hand and unlawful ap- propriation on the other. At identification, it is very important that the label should be characteristic, e.g. in case of credit cards, bonds, cars and the like. It is, however, very important, that the label cannot be falsified and suitably remains invisible under normal circumstances. It is also a very important requirement that the label should not be removed without destruc- tion thus enabling an easy recognition of falsification and unlawful appropriation, resp.

Hungarian Patent No. 212.863 relates to erosion- and water- resistant surface signs of streets, places and parking lots. According to the patent, layers containing transparent glass pearls embedded in an UV- fluorescent binding material are applied.

One form of individual identification signals is that which can be developed by using UV light. Such techniques are used, for example, for labeling paper notes. Hungarian Patent No. 212.215 discloses a process to identify objects, particularly motor vehicles. According to this technology the objects, particularly motor vehicles and parts thereof are labeled with a material which becomes visible when illuminating, among others, with UV light. The labels are applied on the object preferably by painting or printing. SUMMARY OF THE INVENTION

According to the above patent specification, the label may be removed from the surface of the said objects by destruction only. However, as the label is limited to the surface of the said objects only, it has the dis- advantage that after removal by „mild" destruction followed by reconstruction the label cannot be detected any more. According to the only example of this patent specification the label is applied on the motor vehicle by using the paint LUMILUX, there are, however, no data presented relating to the possibility for removing the label. Moreover, there is no reference to the quality or the active substance of the paint. Nevertheless, there is a paint used, which is applied on the paint of the vehicle. Neither the UV-active substance, nor the vehicle of the paint is disclosed, the only information therein is that the LUMILUX is invisible at normal light and cannot be washed off. The disadvantage of the above technology is that - though removable by destruction only - such a removal method is simple to carry out and cannot be detected without the use of more sophisticated apparatus. Therefore, there is a need to a solution which provides a label which cannot be removed at all or, on the other hand, even after removal by a de- struction method, the label remains detectable. An other aim of the invention is that the application of the signal can be carried out in a simple way, if desired, manually as well, and individual labeling could also be applied.

To provide a solution on the above aim, the present invention relates to the use of a combination of a special combination of materials not known in the prior art. The invention also provides special means for the use of the above combinations, which make application of the signal simple and, at the same time, easily readable by UV light. DETAILED DESCRIPTION OF THE INVENTION

One object of the invention is a method which provides the possibility to apply a UV-detectable signal on or in a material the said signal being not removable without substantial destruction. Another object of the invention is a combination of substances which is able to diffuse in the surface of the material to be labeled and which is detectable even if the crystal structure of the material to be labeled does not allow diffusion.

Still another object of the invention is a special labeling means, particularly fiber pen, which enables application of the signal in a very simple way.

The most important feature of the invention is the labeling composition comprising an active material known as optical bleaching compound and at least one solvent. The UV-active material is the 2,5-bis(5-tertiaty butyl-2-benzoxalyl)-thiophene. The compound is a yellow, odorless powder, wherein the commercially available material has a melting point of 196 to 203°C. It is soluble in water in an amount of less than 1 mg/l but soluble in aromatic solvents, ethers, ketones and chlorinated hydrocarbons and moderately soluble in alcohols. The material doesn't decompose, and keeps its excitability for more decades.

The combination according to the invention comprises the above material and at least one solvent. Preferred solvents are esters, preferably butyl acetate, ethers, preferably 1-methoxy-2-propanol and 2-butoxy-ethyl acetate, aromatic solvents, preferably toluene or ketones, preferably cy- clohexanon. In the combination (in the followings: composition) the ratio of the active compound is not critical; the lower limit is determined by the de- tectability of the material, the upper limit is the solubility thereof. Thus the concentration of the active material in the composition is preferably 0,01 to 30 % by weight. In the process according to the invention the above composition is applied on the surface to be labeled. As it is important that the composition diffuses as deep as possible in the structure of the material, the solvent to be used is selected so that its single component, or, in case of using a sol- vent mixture, at least one of the components thereof dissolves or swells the surface of the target material. The advantage of the use of such multi- component solvent mixtures is that one component promotes diffusion while the other components serve as solvent and/or cosolvent.

According to a preferred embodiment of the invention the solvent is a mixture of 1-methoxy-2-propanol, toluene and butyl acetate, or the mixture of butyl acetate, cyclohexanon and 2-butoxy-ethyl acetate.

When investigating numerous structural and functional analogues (optical bleaching agents) it has been found that suitably detectable signal could be produced by the use of the compound of the present invention only while the signal could not be removed only if using the solvents mentioned above.

According to the process of the present invention, application of the composition can be accomplished by any known method, e.g. spraying ( in the first line on painted or smooth, hard surfaces), printing, dipping, or in the form of manuscript, e.g. by using a fiber pen, the fiber pen constituting also an object of the invention.

It is important when applying the signal that the surface should be free of dust and fat residues. Removal of these contaminations may be carried out e.g. by methods known per se, such as washing, with fat- or silicon-solvents. In case of labeling painted surfaces (such as cars) the surface is suitably washed or dabbled with the solvent of the composition to be applied or with at least the solvent component having the swelling effect. The temperature of the surface is not critical; it is, however, advantageous to work at temperatures between room temperature and the de- composition point of the compound, i.e. 350°C, preferred temperature is 20 to 100°C, more preferably 60 to 80°C.

As mentioned, application of the composition may be accomplished by any known method, suitably by painting, spraying, etc. Especially pre- ferred means for application is the fiber pen according to the invention, which can be used most preferably when labeling plastic and paper surfaces. The signals can be applied by computer-controlled ink-jet printer as well.

The fiber pen according to the invention corresponds to any kind of pens used in this area regarding its structure and material with the difference that it contains the composition according to the invention as filling material. The only limiting factor of the fiber pen is that the material thereof, including the outer hull and the inner material being in contact with the filling, may not be damaged by the solvent used in the composition. Due to its properties, the composition according to the invention will not only be retained on the surface, but also incorporates in the structure of the material without damaging the same, and the signal thus prepared cannot be removed in a non-destructive manner.

The fiber pen according to the invention finds a very broad area of use. Its use is especially preferable in case of special documents, e.g. at security insurance, movable of high value, as well as connected with existing security systems, such as for labeling documents, bills of lading, hand tools, complete office apparatus, computers, phones or any other goods. Likewise, the fiber pen according to the invention can also be preferably used for labeling or signing credit cards or other payment forms.

According to a preferred embodiment of the invention the composition can be applied on the surface to be labeled by ink-jet printer connected with computer. This embodiment can preferably be used to label papers or objects made of similar sheets. The signal may be, among others, a number, linear code, script, logo, etc. The signals may be prepared in invisible form, which is developed by UV-light or in visible form which changes color by illuminating with UV. Another area of use of the invention is in the form of matrixes, or other adhesive or self-adhesive labels, such as stickers for insurance companies legalizing payment of insurance fees.

All these embodiments are associated with high property protection value and low costs.

The composition according to the invention, and the use thereof in fiber pen or for labeling vehicles are described in the following examples more in details. However, those skilled in the art will understand that the scope of protection will no way be limited to the special embodiments shown therein. BEST MODE OF CARRYING OUT THE INVENTION Example 1

A composition according to the example was prepared by dissolving 2,5-bis(5-tert. Butyl-2-benzoxalyl)-tiophene in a 2:1 :2 (v/v) mixture of 1- methoxy-2-propanol, toluene and butyl acetate. The final concentration of the UV-active material in the solution was 0,5 %by weight. The composi- tion thus obtained can be used as filling for fiber pens, for printing foils and labeling solid surfaces by spraying as well.

Example 2

A composition according to the example was prepared by dissolv- ing 2,5-bis(5-tert. Butyl-2-benzoxalyl)-tiophene in a 1 ,5:1 :1 (v/v) mixture of cyclohexanon, 2-butoxy-ethyl acetate and butyl acetate. The final concentration of the UV-active material in the solution was 3,5 % by weight. The composition thus obtained can be used as filling for fiber pens, for printing foils and labeling solid surfaces by spraying as well. Example 3

A fiber pen of known structure comprising a fiber filling was filled with the composition according to Example 1. The fiber pen thus prepared was used to write on one side of a plastic-based credit card, dried for one day and illuminated by UV light . The script was readily readable and did not lose its intensity in two years.

Example 4 Dust and fat residues were removed from the polished paint of a car and silicon residues were also removed with suitable anti-silicon composition. The surface was warmed up to 70°C and disposed twice with the solvent mixture used in the composition of Example 1. After 5 minutes, the temperature of the surface was raised to 80°C, the template corresponding to the registration number was placed thereon and, wile keeping the surface temperature, the composition according to Example 1 was sprayed on the paint 6 to 8 times in very this layers. The template was removed 30 seconds after the last spraying, warming was continued for additional 25 minutes, then the surface was allowed to cool to room temperature. The surface thus labeled is preferably to be treated gently in the first week, which, however, does not exclude use of the car.

Example 5

Removability of the compositions according to Examples 1 and 2 was tested on the surface of different materials, at two different times. The fiber pen as described in Example 3 was used for labeling; the said fiber pen containing either composition of Example 1 or Example 2. The surfaces displayed in the Table as herebelow were made fat-free, wiped over with the solvent corresponding to the composition to be applied and la- beled by the fiber pens. Evaluation of removability was accomplished by placing a filtering paper saturated with acetone on the surface, 1 hour and one week after application on separate samples. At 1 hour after application the UV-active compound was detectable in every case on the paper. In cases labeled „-„ only the material adhered on the surface proved to be removable. The active substance diffused in the structure did not change. This is labeled „+" in the column ..diffusion". The surfaces labeled were examined by UV light and the labels were visible on every sample with both composition used.

Table

(+): Diffusion cannot be proved but label clearly detectable.

Claims

1. Composition for producing UV-detectable label comprising 2,5- bis(5-tert-butyl-2-benzoxalyl)-tiophene as UV-active component and at least one solvent selected from esters, ethers, aromatic solvents and ketones.

2. The composition according to claim 1 wherein the ester solvent is butyl acetate, the ether is 1-methoxy-2-propanol or 2-butoxy-ethyl acetate, the aromatic solvent is toluene and the keton is cyclohexanon.

3. The composition according to claim 1 or 2 which comprises the mixture of 1-methoxy-2-propanol, toluene and butyl acetate as solvent.

4. The composition according to claim 1 or 2 which comprises the mixture of cyclohexanon, 2-butoxy-ethyl acetate and butyl acetate as solvent.

5. Fiber pen suitable for UV-detectable labeling which comprises, besides the known parts of such a pen a composition according to claim 1 as filling provided that the solvent of the said filling is inert to any of the parts of the pen.

6. The fiber pen according to claim 5 wherein the filling is the sub- stance as defined in claim 3.

7. The fiber pen according to claim 5 wherein the filling is the substance as defined in claim 4.

8. The use of the compositions according to any of claims 1 to 4 for labeling objects which is detectable by UV-light.

9. The process according to claim 8 wherein the fiber pen of claim 5 is used.

10. The use of 2,5-bis(5-tert-butyl-2-benzoxalyl)-tiophene for UV- detectable labeling of objects.