Security strip and security paper

Abstract

The invention relates to a security strip and security paper for obtaining security documents such as legal tender notes, checks or identification documents, comprising a cellulose support web that is completely embedded in a pulp substrate. As both the substrate and the support web are formed by plant fibers, a series of physical and chemical bonds are established between the fibers of both elements, the support web thus being perfectly integrated in the pulp. The cellulose support web will sometimes have a series of security elements, such as pigments, synthetic elements and/or security fibers of the type normally used in this type of application.

Claims

1. A security strip configured to be embedded in a substrate having hygroscopic plant fibers, said security strip comprising: an elongated cellulose support web made of paper comprising plant fibers; said cellulose support web comprising a body and security elements uniformly dispersed throughout the body; and said security strip being completely embeddable in said substrate, wherein the body of said cellulose support web remains in the substrate as an independent element without disappearing into the substrate when said substrate is wet, wherein exterior surfaces of said support web between terminal ends of said security strip are configured to make direct contact with said substrate and are configured to physically and chemically bond with said substrate, and wherein the security elements are not present on the surface of the security strip.

2. A security strip according to the claim 1, wherein the security elements comprise security pigments.

3. A security strip according to claim 1, wherein the security elements comprise synthetic security elements.

4. A security strip according to claim 1, wherein the security elements comprise security fibers.

5. A security strip according to claim 2, wherein the security pigments are selected from pigments used for coloring paper, pigments used in the manufacture of dyes and pigments with an additional security feature.

6. A security strip according to claim 5, wherein the pigments with an additional security feature are selected from fluorescent pigments, phosphorescent pigments, luminescent pigments, heat-sensitive pigments, magnetic pigments and expandable pigments.

7. A security strip according to claim 5, wherein the security pigments are incorporated in the mass of the support web.

8. A security strip according to claim 5, wherein the security pigments are a first pigment, wherein the first pigment is incorporated in characters selected from alphanumerical characters, symbols, figures, points and bar codes printed on the surface of the support web.

9. A security strip according to claim 3, wherein the synthetic security elements have a regular shape.

10. A security strip according to claim 9, wherein the synthetic security elements incorporate security pigments.

11. A security strip according to claim 4, wherein the security fibers are selected from metallic fibers and magnetic fibers.

12. A security strip according to claim 10, wherein the security pigments are selected from pigments used for coloring paper, pigments used in the manufacture of dyes and pigments with an additional security feature.

13. A security strip according to claim 12, wherein the pigments with an additional security feature are selected from fluorescent pigments, phosphorescent pigments, luminescent pigments, heat-sensitive pigments, magnetic pigments, and expandable pigments.

14. A security strip according to claim 1, wherein said paper weighs up to 80 g/m.sup.2.

15. A security strip according to claim 1, wherein said cellulose support web includes security elements in its body.

16. A security strip according to claim 1, wherein said support web consists of plant fibers.

17. Security paper comprising: a substrate comprising a pulp comprising plant fibers; at least one security strip comprising an elongated cellulose support web made of paper comprising plant fibers and including a body and security elements uniformly dispersed throughout the body, wherein the cellulose support web is embedded in said substrate, the plant fibers of said cellulose support web forming physical and chemical bonds with the plant fibers in the substrate, and the body of said cellulose support web being integrated in the pulp while being retained as an independent element without disappearing into the substrate; wherein said security strip is completely embedded in said substrate, wherein exterior surfaces of said cellulose support web between its terminal ends are in direct contact with said substrate and said security elements are inside said substrate and surrounded by said substrate, and wherein said security elements are not present on the surface of the security strip.

18. A security paper according to claim 17, wherein said substrate comprises two layers and said strip is embedded between said two layers.

19. A security paper according to claim 17, wherein said paper of the cellulose support web weighs up to 80 g/m.sup.2.

20. A security paper according to claim 17, wherein said support web consists of plant fibers.

21. A security document wherein it comprises the security paper described in claim 17.

22. A legal tender note wherein it comprises the security paper described in claim 17.

23. A method for manufacturing a security paper according to claim 17, wherein said security strip is embedded in said substrate when said pulp is wet.

24. A method for manufacturing a security paper according to claim 17, comprising the step of joining two layers of paper together in a sheet formation step to produce a single sheet of said security paper, wherein said security strip is introduced between said two layers of paper.

Description

DESCRIPTION OF THE DRAWINGS

(1) To complement the description which is being made and with the aim of aiding to better understand the features of the invention according to a preferred embodiment thereof, a set of drawings is attached as an integral part of said description in which the following is shown with an illustrative and non-limiting character:

(2) FIG. 1 shows a perspective view of a security strip according to the invention.

(3) FIG. 2 shows a perspective view of a sheet of security paper comprising several cellulose support webs.

(4) FIG. 3 shows a detailed view of the cellulose support web containing security elements and comprised in the security paper.

(5) FIG. 4 shows a perspective view of a legal tender note according to the invention.

PREFERRED EMBODIMENT OF THE INVENTION

(6) In view of the drawings, these show an embodiment of the invention consisting of a security strip (1) comprising a cellulose support web (2) formed by plant fibers (4). Said security strip (1) is applicable in the manufacture of paper intended for obtaining security documents such as legal tender notes (9), checks or passports, among others.

(7) FIG. 1 shows a specific embodiment of the security strip (1) object of this invention. In this case, the strip shown comprises security elements such as security pigments (5) printed in the surface thereof, synthetic security elements (6) and security fibers (7) comprised in the cellulose support web (2).

(8) FIG. 2 shows a perspective view of a sheet of security paper (8) as obtained after passing through the rollers conferring the suitable smoothness and thickness to the paper, before passing through the winding machine which will wind the sheet of paper. The paper shown comprises a substrate (3) consisting of a pulp formed from plant fibers (4), water and other components usually added during the process and several cellulose support webs (2) completely embedded in said substrate (3), said webs being perfectly integrated in the pulp, as can be observed in the figure. In this specific embodiment, the support webs (2) have been introduced perpendicular to the main direction of the sheet of paper, considering as main direction that according to which the paper leaves the machine. However, the possibility of arranging said webs in any other direction is not discarded, and the possibility that that they do not affect the total width of the sheet if the subsequent application of the paper obtained so requires is also contemplated.

(9) As observed with more detail in FIG. 3, the plant fibers (4) comprised in the pulp substrate (3) and those comprised in the cellulose support web (2) combine with one another and form physical and chemical bonds between each other reinforced by the effects of sizing agents incorporated in the process for manufacturing the substrate (3), said incorporation being either in the mass or on the surface, the substrate (3) and the support web (2) then being perfectly bound, such that the support web (2) is completely integrated in said pulp but does not disappear as an independent element. This integration of the cellulose support web (2) in the pulp is due to the fact that the fibers comprised in both elements are plant fibers (4) and therefore their structure is similar, favoring the occurrence of bonds in the support web (2)-substrate (3) contact area, furthermore, since the fibers are plant fibers and therefore hygroscopic, i.e., they absorb moisture, the plant fibers (4) of both elements tend to swell, the adjacent fibers (4) belonging to the same element (support web (2) or pulp substrate (3)) being released and binding to the adjacent fibers (4) of the other element, thus giving rise to multiple new bonds between fibers (4).

(10) In this case shown in FIG. 3 the cellulose support web (2) comprises different security elements, such as security pigments (5) printed on the one of the surfaces thereof, synthetic elements (6) or security fibers (7) with special features for this application. These security elements remain in the support web (2) despite the fact that the latter is completely integrated in the substrate (3).

(11) Once the sheet of security paper (8) object of this invention has been obtained, it is normally cut and printed so that said paper serves as the basis for obtaining any type of security documents, both valuable documents and identification documents. FIG. 4 shows a perspective view of a legal tender note (9) comprising the previously described security paper (8). As observed in this figure, the cellulose support web (2) comprising several security elements is completely embedded in the paper, the obtained note (9) being homogenous (the security strip (1) cannot be sensed by touch).

(12) The manufacture of notes (9) and other documents based on this security paper (8) makes the possibility of detaching the security strip (1) for the counterfeiting thereof extremely difficult, likewise reducing the deterioration of said security strip (1) which, in the event that it were adhered to one of the surfaces of the paper, would undergo considerable damage as a result of its direct exposure to the outside.